From patchwork Sun Jul 14 08:27:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732627 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B01B2282FD; Sun, 14 Jul 2024 08:30:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945807; cv=none; b=mgElkWqMAazC/aJzECL/CMHk18mcM3IRYUfEP+rvdJtoNNJDMM/QiLKoaVZq6kZ8SX++L5qyfelP4Nl17/lqp1BNH0aKVaR3n7QXmWgwcdUlCJZMo/3ERr9Oi3h4K+xfT53PwqYigWTbULv9htP3r4bg0iJJRPWj5g3gwuES7W8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945807; c=relaxed/simple; bh=LpYS83WLCwfoYEIrkASmAZU4pJqGiVpUR3z2uaU37Ro=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TMEnKFvP4v8gkWN70nhAw9H2/pzec/E4dsFcUs/InyBM6jhtapMyv6Bb519Dsm5pgRD0X+OQJ+HoYoED+VBpT7DHTAV6lwvQhWrEiYdnLsPZHEifjww7Dcesdq4mPUbIXXBBXrz6mPsedlqK2IxfeFf7GJ2PUyEN16tV4F1qPUw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XJqJsGGi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XJqJsGGi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DA1EC116B1; Sun, 14 Jul 2024 08:30:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945807; bh=LpYS83WLCwfoYEIrkASmAZU4pJqGiVpUR3z2uaU37Ro=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XJqJsGGit09XBqOHB5LEw6ZRLHjyamWhzZwHwa7PgA8oYEFGYK2DUyoetxnyZpgOr EvFtbYl/fTNqBnpu7kb3xvD2KQ7l41z97Wkixno4IFocFyufkxyulnYEBjTWLyQ8Lu 2iFj4qhy7hsFZtZYg4Mt0TI5eNwPG8NfEdxz4LMoUup9f9QiJHaGIdQSvZKKordgI6 rgJ1fjgHkaz0brF9NSj8Z8el0w1iU+gvPDiaTgjUcxzjfPE+r6xscrBjER1EegqwMo OPTzQ+qXjavbeVMYXZvMl8xBUqNgRCl9YmXRIFXfqbCaS+gMRAaL0472Q6SC4jWAEa rU1TmANJEvDZA== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 01/17] powerpc/trace: Account for -fpatchable-function-entry support by toolchain Date: Sun, 14 Jul 2024 13:57:37 +0530 Message-ID: <12d7c105aea999faa4bcdac8587b3a2899da3461.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 So far, we have relied on the fact that gcc supports both -mprofile-kernel, as well as -fpatchable-function-entry, and clang supports neither. Our Makefile only checks for CONFIG_MPROFILE_KERNEL to decide which files to build. Clang has a feature request out [*] to implement -fpatchable-function-entry, and is unlikely to support -mprofile-kernel. Update our Makefile checks so that we pick up the correct files to build once clang picks up support for -fpatchable-function-entry. [*] https://github.com/llvm/llvm-project/issues/57031 Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/Makefile | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile index 125f4ca588b9..d6c3885453bd 100644 --- a/arch/powerpc/kernel/trace/Makefile +++ b/arch/powerpc/kernel/trace/Makefile @@ -9,12 +9,15 @@ CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_ftrace_64_pg.o = $(CC_FLAGS_FTRACE) endif -obj32-$(CONFIG_FUNCTION_TRACER) += ftrace.o ftrace_entry.o -ifdef CONFIG_MPROFILE_KERNEL -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace.o ftrace_entry.o +ifdef CONFIG_FUNCTION_TRACER +obj32-y += ftrace.o ftrace_entry.o +ifeq ($(CONFIG_MPROFILE_KERNEL)$(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY),) +obj64-y += ftrace_64_pg.o ftrace_64_pg_entry.o else -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o ftrace_64_pg_entry.o +obj64-y += ftrace.o ftrace_entry.o endif +endif + obj-$(CONFIG_TRACING) += trace_clock.o obj-$(CONFIG_PPC64) += $(obj64-y) From patchwork Sun Jul 14 08:27:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732618 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7B9214595B; Sun, 14 Jul 2024 08:29:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945769; cv=none; b=ggZ5/RCE16HJFHuvT66wRaAODz0L0zSjC9nahQLEAAxqa1Ycsv8KvJICk+Src1FkgYKftrtToCnc9smbvPSXc4Zesyf0zQy1CVxPXmtTIKY3d8J1jvWsvkDPJ160f+GSuqN3ELCi+iUWIShH/FZHx0hY40QhjOh5e8ZkOEWAoag= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945769; c=relaxed/simple; bh=Yw7BK5ZSzIqUwdH+xzRKsshvO4agK2xzXRxs7K0POPk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rCk54CLbnntJb9rAvaeWvo35/GK9CL/hnL/Y+tu6Dxr0mJOkvwhGEMl93EDJVFQKxEiq2LjPa5OZIRGPwLqB5nTa3DJOp53TxfDS8S5/405PMZrEU3eNX9ll32QeeT+ihpUwPcCo8AhsvirnTUe6E4+JGfL542pQq0EuLu3BtCg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iu+S2/CO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iu+S2/CO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F9C0C4AF0A; Sun, 14 Jul 2024 08:29:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945769; bh=Yw7BK5ZSzIqUwdH+xzRKsshvO4agK2xzXRxs7K0POPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iu+S2/COmExD2t5/fDyfq7l4ZVCYt9JRCq2RzN28BeGCP0NBLWxXIADnph3qHr7++ I5YmI/fYuJrPObs+vDblAtzHtWjk5PfERvuquk4AGn1wYo6u6O2rRRNjCfNf2FiodN T1JjYiM3b7+z2wgBy83gtr8Je2ojhXe+ppbathOWCyvlKT5FmP0QtZ6ckhnvSQKqyW e1JprOL03fEhjRNxXiby58fOoWl6spkopXuA5gKtgpz3YpJYdFsXWskVdin143+Ak8 TuuHmshZ2OA4nq3Lx/g6Why2YfMiFMWnqBeSUEUKuFXPkh2MRYVBTf1n80ZxvxkTSN FDhfLN4ImhX0Q== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 02/17] powerpc/kprobes: Use ftrace to determine if a probe is at function entry Date: Sun, 14 Jul 2024 13:57:38 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Rather than hard-coding the offset into a function to be used to determine if a kprobe is at function entry, use ftrace_location() to determine the ftrace location within the function and categorize all instructions till that offset to be function entry. For functions that cannot be traced, we fall back to using a fixed offset of 8 (two instructions) to categorize a probe as being at function entry for 64-bit elfv2, unless we are using pcrel. Acked-by: Masami Hiramatsu (Google) Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/kprobes.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 14c5ddec3056..ca204f4f21c1 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -105,24 +105,22 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset) return addr; } -static bool arch_kprobe_on_func_entry(unsigned long offset) +static bool arch_kprobe_on_func_entry(unsigned long addr, unsigned long offset) { -#ifdef CONFIG_PPC64_ELF_ABI_V2 -#ifdef CONFIG_KPROBES_ON_FTRACE - return offset <= 16; -#else - return offset <= 8; -#endif -#else + unsigned long ip = ftrace_location(addr); + + if (ip) + return offset <= (ip - addr); + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + return offset <= 8; return !offset; -#endif } /* XXX try and fold the magic of kprobe_lookup_name() in this */ kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool *on_func_entry) { - *on_func_entry = arch_kprobe_on_func_entry(offset); + *on_func_entry = arch_kprobe_on_func_entry(addr, offset); return (kprobe_opcode_t *)(addr + offset); } From patchwork Sun Jul 14 08:27:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732619 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 924151CA81; Sun, 14 Jul 2024 08:29:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945773; cv=none; b=ktHZoUHQ44JqC/b1JbYDsKD0bO+NW1l0WlBxzAgjDt56r1nFjfP5QFYQX4K/DgOYU9gqc9GrrHmkyALP19XSj8c7q8ZlnSSwZHxu9XGjRJghRY5Do0F6v6KVxC4DmNJhQBpQ7RJ7DuWorwX+wTlirhCkRS/l4kEKoMt80a6dQ0w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945773; c=relaxed/simple; bh=47kbk80bp7tXVEEQCet5lJPGJOYNcBOP1uYRsf338lo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=N9gln89uKsAm0f2s/Hu8KZbn3t/ImCLdaQQXoiQSDI5rfMV5IpNqCdSILoeDiklPBebfQO90By7Qn12npBvN7V4lS89ZaOCAxo9tylnmZc6bATLHP3+Hgz3Ehd9/iqDK+CPF5gCieEHQe7LBw7RBReS1zFmYA5x0sHNBPGyYLHM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WLEI08GH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WLEI08GH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 821D9C116B1; Sun, 14 Jul 2024 08:29:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945773; bh=47kbk80bp7tXVEEQCet5lJPGJOYNcBOP1uYRsf338lo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WLEI08GHjvSjYoDfNMhXk7LjgkS2AY5hdtYIJbTep3tzlvGho2fIxhi/UziKHrJPz H1SRL6HyO/CETYQ2biAhcBtBrnHZ8KylbqpxgTzv+H+s1diMxqhHJ2av8xHOAF/0KI b4KEYYWTPouAgI+dhvn64hl3W/wp+3goKe6eeGltft4XoX/dVR0et2cbbITz435J7D 8Q36P/o5w7apuTfdp3vlO7gCb+HxRTHKG460QfZjtG8l5lLgOkVrWhrghLJDx+odQ0 p/1jfEAjhcNvHd2DJ12INIm2b3KKfKsx6rzCe+LrMeHqzuLvJ8Au+HTiaabomqAq+f RMNOzjMpGHvmQ== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 03/17] powerpc64/ftrace: Nop out additional 'std' instruction emitted by gcc v5.x Date: Sun, 14 Jul 2024 13:57:39 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Gcc v5.x emits a 3-instruction sequence for -mprofile-kernel: mflr r0 std r0, 16(r1) bl _mcount Gcc v6.x moved to a simpler 2-instruction sequence by removing the 'std' instruction. The store saved the return address in the LR save area in the caller stack frame for stack unwinding. However, with dynamic ftrace, we no longer have a call to _mcount on kernel boot when ftrace is not enabled. When ftrace is enabled, that store is performed within ftrace_caller(). As such, the additional 'std' instruction is redundant. Nop it out on kernel boot. With this change, we now use the same 2-instruction profiling sequence with both -mprofile-kernel, as well as -fpatchable-function-entry on 64-bit powerpc. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index d8d6b4fd9a14..2ef504700e8d 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -246,8 +246,12 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) /* Expected sequence: 'mflr r0', ['std r0,16(r1)'], 'bl _mcount' */ ret = ftrace_read_inst(ip - 4, &old); if (!ret && !ppc_inst_equal(old, ppc_inst(PPC_RAW_MFLR(_R0)))) { + /* Gcc v5.x emit the additional 'std' instruction, gcc v6.x don't */ ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0))); - ret |= ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_STD(_R0, _R1, 16))); + if (ret) + return ret; + ret = ftrace_modify_code(ip - 4, ppc_inst(PPC_RAW_STD(_R0, _R1, 16)), + ppc_inst(PPC_RAW_NOP())); } } else { return -EINVAL; From patchwork Sun Jul 14 08:27:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732620 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB4631D559; Sun, 14 Jul 2024 08:29:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945778; cv=none; b=ggSlnGc5CD8Qnt060TNgyuN0AtPwx+TgPiOdl1i2xwzgzEFOyeBmor9iHUD4989yKb4aHWdJYIATjuHt5Bnz1cMQkdbQYnP53OvQRPWo/uH4qLTIoj0zMdmUjMM8no94Uc7sidvzs2t8l+diuEaHkqe3IypXUD8DXrpSgFFbZC8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945778; c=relaxed/simple; bh=AHR4/JGyg5TPmVP3bzTkFu+vZK+lkm0Waf1/cjS2xT0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RFFil8bpIk9rS+iw7lfkDU9d5gAPR7Q2rneFblHEO7+fvl54VUqd/nXoFMdGrwsmgv0D4VmWUoTjL+ejuNH9if6i/QhborUzyMEkfKKTECe1TE7DOV4M4U1OZu0ujN4BeS0yF4e7cMnQSiQRLFuBMr0ZrcwuO8rCpoywmbr4/9I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=toD/dL/e; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="toD/dL/e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBA87C4AF09; Sun, 14 Jul 2024 08:29:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945777; bh=AHR4/JGyg5TPmVP3bzTkFu+vZK+lkm0Waf1/cjS2xT0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=toD/dL/eQEsUiyfYDoEK6XuBkkK+oUQPq1we50+G+jrKS87rWXlJJVpGpSEWphKHN 1aHX3ZqQWmtHtgyxNbiwMmGob2SLrPBuzZ6vM1SkGlb1J+MICOqyAOKWQwxMXCvEt9 9STw8D+S9mHx+r9P+Tp3g4AhUiZouQFylUcWI0FquSvBVCtS45KWG+/gAH1KqLe9Vh or5UfGvDYhikdq6eDzq2H1EgdcAD+3p8crSFl3P4oFIUESKw9VsvHMNPgdW6GMPg2i +hP2DxgIxikLfCA4bMVxF7e6SLg9jQijPQTlc3pMVZepPbbycLnwOJ8yzfL1ifDwHP 2d6UIrcgky2/A== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 04/17] powerpc32/ftrace: Unify 32-bit and 64-bit ftrace entry code Date: Sun, 14 Jul 2024 13:57:40 +0530 Message-ID: <4bad5f42d5035f7262b0b770b5e61dc7bbafd25e.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On 32-bit powerpc, gcc generates a three instruction sequence for function profiling: mflr r0 stw r0, 4(r1) bl _mcount On kernel boot, the call to _mcount() is nop-ed out, to be patched back in when ftrace is actually enabled. The 'stw' instruction therefore is not necessary unless ftrace is enabled. Nop it out during ftrace init. When ftrace is enabled, we want the 'stw' so that stack unwinding works properly. Perform the same within the ftrace handler, similar to 64-bit powerpc. Reviewed-by: Nicholas Piggin Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 6 ++++-- arch/powerpc/kernel/trace/ftrace_entry.S | 4 ++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 2ef504700e8d..8c3e523e4f96 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -240,8 +240,10 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) } else if (IS_ENABLED(CONFIG_PPC32)) { /* Expected sequence: 'mflr r0', 'stw r0,4(r1)', 'bl _mcount' */ ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0))); - if (!ret) - ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_STW(_R0, _R1, 4))); + if (ret) + return ret; + ret = ftrace_modify_code(ip - 4, ppc_inst(PPC_RAW_STW(_R0, _R1, 4)), + ppc_inst(PPC_RAW_NOP())); } else if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { /* Expected sequence: 'mflr r0', ['std r0,16(r1)'], 'bl _mcount' */ ret = ftrace_read_inst(ip - 4, &old); diff --git a/arch/powerpc/kernel/trace/ftrace_entry.S b/arch/powerpc/kernel/trace/ftrace_entry.S index 76dbe9fd2c0f..244a1c7bb1e8 100644 --- a/arch/powerpc/kernel/trace/ftrace_entry.S +++ b/arch/powerpc/kernel/trace/ftrace_entry.S @@ -33,6 +33,8 @@ * and then arrange for the ftrace function to be called. */ .macro ftrace_regs_entry allregs + /* Save the original return address in A's stack frame */ + PPC_STL r0, LRSAVE(r1) /* Create a minimal stack frame for representing B */ PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) @@ -44,8 +46,6 @@ SAVE_GPRS(3, 10, r1) #ifdef CONFIG_PPC64 - /* Save the original return address in A's stack frame */ - std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1) /* Ok to continue? */ lbz r3, PACA_FTRACE_ENABLED(r13) cmpdi r3, 0 From patchwork Sun Jul 14 08:27:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732621 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 169971D559; Sun, 14 Jul 2024 08:29:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945782; cv=none; b=XSdqqGnlAw8tYSmERvl8lJuGy8w8yYoPAzcZRUmYce6ZK0YKeKD//rTb+f9JwVRNm55Va49JONib4SHaYijkIpj1y8bNj70/pIX7OHXQFOq4T9M8MhnoW7Hepdp1eXKu0wRAnFqiisXXw5y14rYPIikUmVfY6HuJ9HLyrG8Cy40= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945782; c=relaxed/simple; bh=hcwZI/Cz4N2FGpqi2ddwK6JV0n+9v2tr6M/Imbpdp7o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kJvm8Fu5OsvfcV8souxaNMA7OhPoFPOM2FVB8mXKrqTh7ICPiP6UVHBjiFr6gcUNw/fsH6VIvv0NT1qQeSHxNciOIFzMRaLMcH36F5fouYs7xg2JakkiDiKo2h853CVOfC+rkJLUbpFtZfEoCKLrAKsiHY6ObMJQ2brA39mfa/0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P2nELLwT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P2nELLwT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3398C116B1; Sun, 14 Jul 2024 08:29:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945781; bh=hcwZI/Cz4N2FGpqi2ddwK6JV0n+9v2tr6M/Imbpdp7o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P2nELLwTExThswaNc3gvJbTEHCVHQG8q3TDv+8qWn0dUsPg3NgQTBhueuZqPUYB0R uKsn+It1hk3tYrV3TFNALoZDe9E1h/hCUf4fjike7RaycGcA0dfxOrjqnf64k+ly1z MgIT1m0Tq/Re+eiK9SGoVe4yO0vUp5vmYMhpIBPB68NU8tE5Kt2xsB/REoZSWraFti qTlL0+VJI3s84x508yJ14T5V3yanX43PLvaDTRJmczicKACS/ox2egOCQWFa/XrOBz bzhi3BQfRhlyZv9Khpw/vIVK3a6g2Si3ki95bt5Hfv+GDZUyaPh3rJS9KGTrUmu/TR Oxer6ihxFwK3w== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 05/17] powerpc/module_64: Convert #ifdef to IS_ENABLED() Date: Sun, 14 Jul 2024 13:57:41 +0530 Message-ID: <212c6945c642a8805c73e48d63e63ab5edcaa5dd.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Minor refactor for converting #ifdef to IS_ENABLED(). Reviewed-by: Nicholas Piggin Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/module_64.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index e9bab599d0c2..1db88409bd95 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c @@ -241,14 +241,8 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, } } -#ifdef CONFIG_DYNAMIC_FTRACE - /* make the trampoline to the ftrace_caller */ - relocs++; -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS - /* an additional one for ftrace_regs_caller */ - relocs++; -#endif -#endif + /* stubs for ftrace_caller and ftrace_regs_caller */ + relocs += IS_ENABLED(CONFIG_DYNAMIC_FTRACE) + IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS); pr_debug("Looks like a total of %lu stubs, max\n", relocs); return relocs * sizeof(struct ppc64_stub_entry); From patchwork Sun Jul 14 08:27:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732622 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 170E34AECB; Sun, 14 Jul 2024 08:29:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945786; cv=none; b=WNLpKqL8W5EF+ZAzUEJ6DpNHnAmIJ3HsZQeMl2d0WWKTzEX9koWTzX+kxr8JUppsKGkwoEZ9HQiYOysEQcBLHArrRgt0l74XDuTWX4rzXY985s8UHArSn0dg4D/CNpvZ4Lyns0FIei0Gl1fzvBXuU50jER0uDlPGRk/GKdedmsQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945786; c=relaxed/simple; bh=Obemq1PkXgUxv63tDsRVkWT5+WyPEPtD6ghMCi268o4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BdPxRLLlPzrRUJfrioam3i+79zrlEccGp0yZ3ycaQSTWi53zEuoWqNoAO3mD7B/dF0OCaVUWtarCY3vrZVzXbtoD0sG3wxsDAvkyaeppXeemMMSWFI/I08MbrKnJy8moJ6BUjVSxCrCdUImfxBTnA43MXg4J/8lPqTIZFnfAkCg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=vPl393gE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="vPl393gE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A87AC116B1; Sun, 14 Jul 2024 08:29:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945786; bh=Obemq1PkXgUxv63tDsRVkWT5+WyPEPtD6ghMCi268o4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vPl393gE7nH9lr1pGHwFK83POdL//kREe62eDET3A+j8Y6PHR0CM7Iu12updQuxWu HdRUdtD9WVmZznfr4zEIjCOh+21F/GQyrXBHtkdB1Xt9DspdfZpfOPC1O9gYa5OaDI PfLwjX9T9e9/TfB9nUL8o7rNsC4ZbQ8PKtz/w4jVtQZOWltgNgMI96QZkRvVwBdA6w kSivV/qFaHVcWAO0UyCYY40oDG3FzIMy6JD+V0aAHpdu3o7Agbx7IDBBYwXEzDkRZN rkvbGJ1QSVZwzne9Mb78wMqkhp/1mgH01w4F75iZbykWPr1UplrBbweWK6t8lWsR0p MkuQ3+pITchjA== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 06/17] powerpc/ftrace: Remove pointer to struct module from dyn_arch_ftrace Date: Sun, 14 Jul 2024 13:57:42 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Pointer to struct module is only relevant for ftrace records belonging to kernel modules. Having this field in dyn_arch_ftrace wastes memory for all ftrace records belonging to the kernel. Remove the same in favour of looking up the module from the ftrace record address, similar to other architectures. Reviewed-by: Nicholas Piggin Signed-off-by: Naveen N Rao --- arch/powerpc/include/asm/ftrace.h | 1 - arch/powerpc/kernel/trace/ftrace.c | 49 +++++++++-------- arch/powerpc/kernel/trace/ftrace_64_pg.c | 69 ++++++++++-------------- 3 files changed, 56 insertions(+), 63 deletions(-) diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 107fc5a48456..201f9d15430a 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -26,7 +26,6 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, struct module; struct dyn_ftrace; struct dyn_arch_ftrace { - struct module *mod; }; #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 8c3e523e4f96..fe0546fbac8e 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -106,28 +106,43 @@ static unsigned long find_ftrace_tramp(unsigned long ip) return 0; } +#ifdef CONFIG_MODULES +static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long addr) +{ + struct module *mod = NULL; + + preempt_disable(); + mod = __module_text_address(ip); + preempt_enable(); + + if (!mod) + pr_err("No module loaded at addr=%lx\n", ip); + + return (addr == (unsigned long)ftrace_caller ? mod->arch.tramp : mod->arch.tramp_regs); +} +#else +static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long addr) +{ + return 0; +} +#endif + static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_inst_t *call_inst) { unsigned long ip = rec->ip; unsigned long stub; - if (is_offset_in_branch_range(addr - ip)) { + if (is_offset_in_branch_range(addr - ip)) /* Within range */ stub = addr; -#ifdef CONFIG_MODULES - } else if (rec->arch.mod) { - /* Module code would be going to one of the module stubs */ - stub = (addr == (unsigned long)ftrace_caller ? rec->arch.mod->arch.tramp : - rec->arch.mod->arch.tramp_regs); -#endif - } else if (core_kernel_text(ip)) { + else if (core_kernel_text(ip)) /* We would be branching to one of our ftrace stubs */ stub = find_ftrace_tramp(ip); - if (!stub) { - pr_err("0x%lx: No ftrace stubs reachable\n", ip); - return -EINVAL; - } - } else { + else + stub = ftrace_lookup_module_stub(ip, addr); + + if (!stub) { + pr_err("0x%lx: No ftrace stubs reachable\n", ip); return -EINVAL; } @@ -262,14 +277,6 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) if (ret) return ret; - if (!core_kernel_text(ip)) { - if (!mod) { - pr_err("0x%lx: No module provided for non-kernel address\n", ip); - return -EFAULT; - } - rec->arch.mod = mod; - } - /* Nop-out the ftrace location */ new = ppc_inst(PPC_RAW_NOP()); addr = MCOUNT_ADDR; diff --git a/arch/powerpc/kernel/trace/ftrace_64_pg.c b/arch/powerpc/kernel/trace/ftrace_64_pg.c index 12fab1803bcf..8a551dfca3d0 100644 --- a/arch/powerpc/kernel/trace/ftrace_64_pg.c +++ b/arch/powerpc/kernel/trace/ftrace_64_pg.c @@ -116,6 +116,20 @@ static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) } #ifdef CONFIG_MODULES +static struct module *ftrace_lookup_module(struct dyn_ftrace *rec) +{ + struct module *mod; + + preempt_disable(); + mod = __module_text_address(rec->ip); + preempt_enable(); + + if (!mod) + pr_err("No module loaded at addr=%lx\n", rec->ip); + + return mod; +} + static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) @@ -124,6 +138,12 @@ __ftrace_make_nop(struct module *mod, unsigned long ip = rec->ip; ppc_inst_t op, pop; + if (!mod) { + mod = ftrace_lookup_module(rec); + if (!mod) + return -EINVAL; + } + /* read where this goes */ if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { pr_err("Fetching opcode failed.\n"); @@ -366,27 +386,6 @@ int ftrace_make_nop(struct module *mod, return -EINVAL; } - /* - * Out of range jumps are called from modules. - * We should either already have a pointer to the module - * or it has been passed in. - */ - if (!rec->arch.mod) { - if (!mod) { - pr_err("No module loaded addr=%lx\n", addr); - return -EFAULT; - } - rec->arch.mod = mod; - } else if (mod) { - if (mod != rec->arch.mod) { - pr_err("Record mod %p not equal to passed in mod %p\n", - rec->arch.mod, mod); - return -EINVAL; - } - /* nothing to do if mod == rec->arch.mod */ - } else - mod = rec->arch.mod; - return __ftrace_make_nop(mod, rec, addr); } @@ -411,7 +410,10 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) ppc_inst_t op[2]; void *ip = (void *)rec->ip; unsigned long entry, ptr, tramp; - struct module *mod = rec->arch.mod; + struct module *mod = ftrace_lookup_module(rec); + + if (!mod) + return -EINVAL; /* read where this goes */ if (copy_inst_from_kernel_nofault(op, ip)) @@ -533,16 +535,6 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) return -EINVAL; } - /* - * Out of range jumps are called from modules. - * Being that we are converting from nop, it had better - * already have a module defined. - */ - if (!rec->arch.mod) { - pr_err("No module loaded\n"); - return -EINVAL; - } - return __ftrace_make_call(rec, addr); } @@ -555,7 +547,10 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, ppc_inst_t op; unsigned long ip = rec->ip; unsigned long entry, ptr, tramp; - struct module *mod = rec->arch.mod; + struct module *mod = ftrace_lookup_module(rec); + + if (!mod) + return -EINVAL; /* If we never set up ftrace trampolines, then bail */ if (!mod->arch.tramp || !mod->arch.tramp_regs) { @@ -668,14 +663,6 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, return -EINVAL; } - /* - * Out of range jumps are called from modules. - */ - if (!rec->arch.mod) { - pr_err("No module loaded\n"); - return -EINVAL; - } - return __ftrace_modify_call(rec, old_addr, addr); } #endif From patchwork Sun Jul 14 08:27:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732623 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96F944AECB; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ug3WLnQh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76AA3C116B1; Sun, 14 Jul 2024 08:29:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945790; bh=LJPviOMmRIjz0uro4r36QiA8kKEiN0rClRqnRvEe5pc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ug3WLnQhtxYBuJ3k5NkmRlo7cmPPGONQDtikam7v0eKto6gU2mk16oxGh+1+HxGR4 /JjEiD3VTDoYyrHzuBVgAlt7TlAVddyYeGuVmytB5zYxN1A4/PCUsr0WFJbyQi2bYM FASrcPigNL4lAUGQU5GhSslZCWjqUoLKXlWAgMYjhrU0an5dpQhUAU/290RkI4FsAD oYShdgBIqm3Fea0HO+v3Ag4jNNwRrD6IHZWKJ436F5mGy/+jojZ0bPS22hsrJ02Iz2 PXu1Pyy2IVUxvJCzw4LAAabMwxkAuEEmIdMf3lX24ZCCU/496TWOxWFZM9Z6Yo3N0o KH9kYrZSWOxvw== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 07/17] powerpc/ftrace: Skip instruction patching if the instructions are the same Date: Sun, 14 Jul 2024 13:57:43 +0530 Message-ID: <2aba0401f39fee0726e3342b21160d2b05bfa53b.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To simplify upcoming changes to ftrace, add a check to skip actual instruction patching if the old and new instructions are the same. We still validate that the instruction is what we expect, but don't actually patch the same instruction again. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index fe0546fbac8e..719517265d39 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -82,7 +82,7 @@ static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_ { int ret = ftrace_validate_inst(ip, old); - if (!ret) + if (!ret && !ppc_inst_equal(old, new)) ret = patch_instruction((u32 *)ip, new); return ret; From patchwork Sun Jul 14 08:27:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732624 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8D00722313; Sun, 14 Jul 2024 08:29:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945794; cv=none; b=g0awvAXZeudxIBAxT9e0E3RJuQFvSHAB+tZRaigMQgIGARasOsz4liMYZP0bNyPktlA0M8IcOfiAiSDRYq/oLB4vvb4pveWj4URqdtXj9cZ14DHQfmwjvd0/XgVI+6oNmLop2+Zq/l0H8mewoU5LlKTj3ppvaoCxeGVQNU9WUmo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945794; c=relaxed/simple; bh=Mm/vplktDeK53IWrh3itHTbGXRGKBBYh38qELYFlNEQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qESUBcixE3brF53/h2pevlyUDU8xl7cKIdySnpKOOrtYMhwNfbyX6XoS29FwP/O8O5+3mlGLY8kBFWk1hJzzjeO68mrbzE80wsTvv696bJ6MQBwPhROX967Nmk07A87FxOdya+iexrKooiPtPIYKuGOrCFOQf/RjRQPvqA53TWQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=stapOdy5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="stapOdy5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1705C116B1; Sun, 14 Jul 2024 08:29:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945794; bh=Mm/vplktDeK53IWrh3itHTbGXRGKBBYh38qELYFlNEQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=stapOdy5N4c8llhRcXvRrV2vbGUQLT6Hj3ExUX7QaGkrpIjrCwe6YH514stkMyCBF AsGWkJpmXodE2OTVhBmDwTR9ElgKPuwagg2+0jVfefLnP1EVqqQ0/4E4qeDNiA9aAW ZPisF5J1ctW2+D7aOzCl8gmhBXXwaenz2B/hu41Px/xuB4bCDbwsQ51y4y+glnIEmH /4POmB+DapyXuPhUxi9IP1TtCNCfo9bC3thQ8sOIqlwqpPddTkU1Lyc4TOGm0nZGeN gg9xSx7sHSNCZlWhqf93j2mjYXCQDnejOu7drshSpl/SMU2Cnm6mM91PfMyO+yU1M9 y6EOBnNTWF12g== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 08/17] powerpc/ftrace: Move ftrace stub used for init text before _einittext Date: Sun, 14 Jul 2024 13:57:44 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Move the ftrace stub used to cover inittext before _einittext so that it is within kernel text, as seen through core_kernel_text(). This is required for a subsequent change to ftrace. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/vmlinux.lds.S | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index f420df7888a7..0aef9959f2cd 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -267,14 +267,13 @@ SECTIONS .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) { _sinittext = .; INIT_TEXT - + *(.tramp.ftrace.init); /* *.init.text might be RO so we must ensure this section ends on * a page boundary. */ . = ALIGN(PAGE_SIZE); _einittext = .; - *(.tramp.ftrace.init); } :text /* .exit.text is discarded at runtime, not link time, From patchwork Sun Jul 14 08:27:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732625 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2E0935EE97; Sun, 14 Jul 2024 08:29:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945799; cv=none; b=WBypIajbkTVUvtODBwdz8bvSlcS07YzxNtdUjSOxFZXgT/P4iV5e9RR4xmAAM1BiViFyTky0ItF0jGIcCy/ngqjc9it+8sQSxLew+EPECtRRxjh5BnZ+q1bbrFDedMyLW/55t5ZpgJ+aBj9u17tu7b0Qfn9p8Xu8ymnFm1kbjKI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945799; c=relaxed/simple; bh=IskF71GDKHjgxuqQkVkMv1lu202Is52qU3cvSr5TzWg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HDGD/ZVumKTrOU94k0zyF8sxEm8vg7KINKUJO177pH3rB7fpk/Zs2SLaEPkS6yOzHnBmRn4dsRioGBFB4l+eMMUYFZ7TDQxdASpNRFPAKfsMkh4h9RJmkc5sMLflorlASBRlF5YnG1KlDONqVM/KrJOLBBXuw0mgHLmtqYM0keA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ez2dMaHK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ez2dMaHK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 003A3C116B1; Sun, 14 Jul 2024 08:29:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945798; bh=IskF71GDKHjgxuqQkVkMv1lu202Is52qU3cvSr5TzWg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ez2dMaHKVcxvJb5HVREOY3vyA8FdKoFQ2VCsgb9kbKy+Se7X83ieG3zMzk7beBRVs hz/u5AWz7B8yPyYWMGCBXauJ8IwLW7fynI9ORXtAzRqGgJG+Qbi0Wz6jxIvBbPa8Jm rZ5IpQyP2vGpnc1DEvVFoNJwgMFgphkrpcgQQHBuinoHiRgxKBiGnY+87gh7IiiAvr Owog/3UBfZ6KE/OgKxjYghrMC74PjcLcLk3AUGX/RawP7axcr+ilvlK88/eYq1CewD vxSJB07wQq+dc3Uq11gwPPwZQQYsepHTiSxelPOH19JEtCJtPNOxx3Ruteqi53j4GK +MQYRzJq5rESw== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 09/17] powerpc64/bpf: Fold bpf_jit_emit_func_call_hlp() into bpf_jit_emit_func_call_rel() Date: Sun, 14 Jul 2024 13:57:45 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Commit 61688a82e047 ("powerpc/bpf: enable kfunc call") enhanced bpf_jit_emit_func_call_hlp() to handle calls out to module region, where bpf progs are generated. The only difference now between bpf_jit_emit_func_call_hlp() and bpf_jit_emit_func_call_rel() is in handling of the initial pass where target function address is not known. Fold that logic into bpf_jit_emit_func_call_hlp() and rename it to bpf_jit_emit_func_call_rel() to simplify bpf function call JIT code. We don't actually need to load/restore TOC across a call out to a different kernel helper or to a different bpf program since they all work with the kernel TOC. We only need to do it if we have to call out to a module function. So, guard TOC load/restore with appropriate conditions. Signed-off-by: Naveen N Rao --- arch/powerpc/net/bpf_jit_comp64.c | 61 +++++++++---------------------- 1 file changed, 17 insertions(+), 44 deletions(-) diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 2cbcdf93cc19..f3be024fc685 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -202,14 +202,22 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) EMIT(PPC_RAW_BLR()); } -static int -bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func) +int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func) { unsigned long func_addr = func ? ppc_function_entry((void *)func) : 0; long reladdr; - if (WARN_ON_ONCE(!kernel_text_address(func_addr))) - return -EINVAL; + /* bpf to bpf call, func is not known in the initial pass. Emit 5 nops as a placeholder */ + if (!func) { + for (int i = 0; i < 5; i++) + EMIT(PPC_RAW_NOP()); + /* elfv1 needs an additional instruction to load addr from descriptor */ + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1)) + EMIT(PPC_RAW_NOP()); + EMIT(PPC_RAW_MTCTR(_R12)); + EMIT(PPC_RAW_BCTRL()); + return 0; + } #ifdef CONFIG_PPC_KERNEL_PCREL reladdr = func_addr - local_paca->kernelbase; @@ -266,7 +274,8 @@ bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, * We can clobber r2 since we get called through a * function pointer (so caller will save/restore r2). */ - EMIT(PPC_RAW_LD(_R2, bpf_to_ppc(TMP_REG_2), 8)); + if (is_module_text_address(func_addr)) + EMIT(PPC_RAW_LD(_R2, bpf_to_ppc(TMP_REG_2), 8)); } else { PPC_LI64(_R12, func); EMIT(PPC_RAW_MTCTR(_R12)); @@ -276,46 +285,14 @@ bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, * Load r2 with kernel TOC as kernel TOC is used if function address falls * within core kernel text. */ - EMIT(PPC_RAW_LD(_R2, _R13, offsetof(struct paca_struct, kernel_toc))); + if (is_module_text_address(func_addr)) + EMIT(PPC_RAW_LD(_R2, _R13, offsetof(struct paca_struct, kernel_toc))); } #endif return 0; } -int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func) -{ - unsigned int i, ctx_idx = ctx->idx; - - if (WARN_ON_ONCE(func && is_module_text_address(func))) - return -EINVAL; - - /* skip past descriptor if elf v1 */ - func += FUNCTION_DESCR_SIZE; - - /* Load function address into r12 */ - PPC_LI64(_R12, func); - - /* For bpf-to-bpf function calls, the callee's address is unknown - * until the last extra pass. As seen above, we use PPC_LI64() to - * load the callee's address, but this may optimize the number of - * instructions required based on the nature of the address. - * - * Since we don't want the number of instructions emitted to increase, - * we pad the optimized PPC_LI64() call with NOPs to guarantee that - * we always have a five-instruction sequence, which is the maximum - * that PPC_LI64() can emit. - */ - if (!image) - for (i = ctx->idx - ctx_idx; i < 5; i++) - EMIT(PPC_RAW_NOP()); - - EMIT(PPC_RAW_MTCTR(_R12)); - EMIT(PPC_RAW_BCTRL()); - - return 0; -} - static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out) { /* @@ -1102,11 +1079,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct code if (ret < 0) return ret; - if (func_addr_fixed) - ret = bpf_jit_emit_func_call_hlp(image, fimage, ctx, func_addr); - else - ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr); - + ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr); if (ret) return ret; From patchwork Sun Jul 14 08:27:46 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732626 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6493513E04C; Sun, 14 Jul 2024 08:30:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945803; cv=none; b=t4NW/PUByf74nADVq++mUpT4cK+KCEIrR9fR0dBQhLTmPqY+Dj2Pq4RwsOU/1ypRfrMSvlMIDaeVW3lB3GxCtld5PUsFqVNclh952PD31T0MQSixWIQZlM/ZMt+7NCYuOaM1kXKoInbPsF6TonfQD/IMH0pEHDZ23UCrkxPpvsQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945803; c=relaxed/simple; bh=Ioka5XsUMFumHCOKG404RsMEfa4dS57u3guGUJVji54=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WJnQ2RPbDebaIDDgDNNVDJFmTMOGV0cbUFsZue/nalGiB2RX9FPjjxr8Q1R30zVOfOtZTtY6z2ckFMfcFpTtmxi0n5tibNIw1xTVs6HRg56w+/1Jzt0IdJyRQ3bwep7+3KTuqnbAiZMY3Lh7rP83Hk0fpT2oheuHnDHAVcKqASc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Zt2BoB7W; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Zt2BoB7W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41CD9C116B1; Sun, 14 Jul 2024 08:30:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945803; bh=Ioka5XsUMFumHCOKG404RsMEfa4dS57u3guGUJVji54=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zt2BoB7WmSNdxKHJLar2STWNDmvm7TCUzM6Uhx0zZWtC2oKyLQZj4RLu/7TjiNKCH 8TsXwBXRyIE5jymoJIYqlhPkNeNvqB+Fuvr4VVWKSBMsuYYd7w9SRW0Mtl3UiS9+8W i8jEHMIRr0/9kMS9CFJJ1iizH7R+gjGSRLvKueKA/5KJhgjNf3grHiHrwaqPo12H0g 5qeVB6cDApxSZkxmDWLq0iRzJpwKqVX0nvrqtlawp9P1yhZXXWlJ3lfQ/Mh5yLJ0KE jt4pHTN0gjcVmYI58HwrS0IIpkYY9BI0FHVxjVl+qPWO4Euswyvecc6RMG99ocVh0+ Rh9I6z+6YoUhA== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 10/17] powerpc/ftrace: Add a postlink script to validate function tracer Date: Sun, 14 Jul 2024 13:57:46 +0530 Message-ID: <6eac5cc2848a08778dc8ebe6477f3b8ad98f7947.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Function tracer on powerpc can only work with vmlinux having a .text size of up to ~64MB due to powerpc branch instruction having a limited relative branch range of 32MB. Today, this is only detected on kernel boot when ftrace is init'ed. Add a post-link script to check the size of .text so that we can detect this at build time, and break the build if necessary. We add a dependency on !COMPILE_TEST for CONFIG_HAVE_FUNCTION_TRACER so that allyesconfig and other test builds can continue to work without enabling ftrace. Signed-off-by: Naveen N Rao --- arch/powerpc/Kconfig | 2 +- arch/powerpc/Makefile.postlink | 8 ++++++ arch/powerpc/tools/ftrace_check.sh | 45 ++++++++++++++++++++++++++++++ 3 files changed, 54 insertions(+), 1 deletion(-) create mode 100755 arch/powerpc/tools/ftrace_check.sh diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index f8891fbe7c16..68f0e7a5576f 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -244,7 +244,7 @@ config PPC select HAVE_FUNCTION_DESCRIPTORS if PPC64_ELF_ABI_V1 select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FUNCTION_GRAPH_TRACER - select HAVE_FUNCTION_TRACER if PPC64 || (PPC32 && CC_IS_GCC) + select HAVE_FUNCTION_TRACER if !COMPILE_TEST && (PPC64 || (PPC32 && CC_IS_GCC)) select HAVE_GCC_PLUGINS if GCC_VERSION >= 50200 # plugin support on gcc <= 5.1 is buggy on PPC select HAVE_GENERIC_VDSO select HAVE_HARDLOCKUP_DETECTOR_ARCH if PPC_BOOK3S_64 && SMP diff --git a/arch/powerpc/Makefile.postlink b/arch/powerpc/Makefile.postlink index ae5a4256b03d..bb601be36173 100644 --- a/arch/powerpc/Makefile.postlink +++ b/arch/powerpc/Makefile.postlink @@ -24,6 +24,9 @@ else $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/relocs_check.sh "$(OBJDUMP)" "$(NM)" "$@" endif +quiet_cmd_ftrace_check = CHKFTRC $@ + cmd_ftrace_check = $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/ftrace_check.sh "$(NM)" "$@" + # `@true` prevents complaint when there is nothing to be done vmlinux: FORCE @@ -34,6 +37,11 @@ endif ifdef CONFIG_RELOCATABLE $(call if_changed,relocs_check) endif +ifdef CONFIG_FUNCTION_TRACER +ifndef CONFIG_PPC64_ELF_ABI_V1 + $(call cmd,ftrace_check) +endif +endif clean: rm -f .tmp_symbols.txt diff --git a/arch/powerpc/tools/ftrace_check.sh b/arch/powerpc/tools/ftrace_check.sh new file mode 100755 index 000000000000..33f2fd45e54d --- /dev/null +++ b/arch/powerpc/tools/ftrace_check.sh @@ -0,0 +1,45 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-or-later +# +# This script checks vmlinux to ensure that all functions can call ftrace_caller() either directly, +# or through the stub, ftrace_tramp_text, at the end of kernel text. + +# Error out if any command fails +set -e + +# Allow for verbose output +if [ "$V" = "1" ]; then + set -x +fi + +if [ $# -lt 2 ]; then + echo "$0 [path to nm] [path to vmlinux]" 1>&2 + exit 1 +fi + +# Have Kbuild supply the path to nm so we handle cross compilation. +nm="$1" +vmlinux="$2" + +stext_addr=$($nm "$vmlinux" | grep -e " [TA] _stext$" | cut -d' ' -f1 | tr '[[:lower:]]' '[[:upper:]]') +ftrace_caller_addr=$($nm "$vmlinux" | grep -e " T ftrace_caller$" | cut -d' ' -f1 | tr '[[:lower:]]' '[[:upper:]]') +ftrace_tramp_addr=$($nm "$vmlinux" | grep -e " T ftrace_tramp_text$" | cut -d' ' -f1 | tr '[[:lower:]]' '[[:upper:]]') + +ftrace_caller_offset=$(echo "ibase=16;$ftrace_caller_addr - $stext_addr" | bc) +ftrace_tramp_offset=$(echo "ibase=16;$ftrace_tramp_addr - $ftrace_caller_addr" | bc) +sz_32m=$(printf "%d" 0x2000000) +sz_64m=$(printf "%d" 0x4000000) + +# ftrace_caller - _stext < 32M +if [ $ftrace_caller_offset -ge $sz_32m ]; then + echo "ERROR: ftrace_caller (0x$ftrace_caller_addr) is beyond 32MiB of _stext" 1>&2 + echo "ERROR: consider disabling CONFIG_FUNCTION_TRACER, or reducing the size of kernel text" 1>&2 + exit 1 +fi + +# ftrace_tramp_text - ftrace_caller < 64M +if [ $ftrace_tramp_offset -ge $sz_64m ]; then + echo "ERROR: kernel text extends beyond 64MiB from ftrace_caller" 1>&2 + echo "ERROR: consider disabling CONFIG_FUNCTION_TRACER, or reducing the size of kernel text" 1>&2 + exit 1 +fi From patchwork Sun Jul 14 08:27:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732590 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 00E3A14AB2; Sun, 14 Jul 2024 08:28:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945739; cv=none; b=FF0gDIFbJl4zwNaIP4IIMWewt9YMITVN60F9Rmh0cS0mFXBTVXTp21wM+rENHlf80k7rG44obRgQ0a2h6cqkP+G5cfJOpeqcbHKb6hb71MrY4XN94AnCmVNy0L0KB1Ep58GF/bdFLX9cMmljlB5TNSrogUgTvDZ6GtScbyH2wbc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945739; c=relaxed/simple; bh=OqYXQllYDdxc5CmUvaNfhz68rWXiRNRgAQYB5EiR7Zw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BfVZ2T4wvktvngOXbIVv3rkYmQSJb9eoQcttCmkA7SvIpukeHizI0j6j1jDt9yj62anMtd7W8/pW1geRDsrAr2aRBR0bnnJLHLsArrwgU0lYcPcdR2Gl6jjv4N4HgvYVcNK/NMNqJ+AFGCwgsjAhPGs2DQffl2Z0aLg9ubLQPSU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GUE1SjR6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GUE1SjR6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CADE4C116B1; Sun, 14 Jul 2024 08:28:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945738; bh=OqYXQllYDdxc5CmUvaNfhz68rWXiRNRgAQYB5EiR7Zw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GUE1SjR6gGuw/Pmgslop0RoSjIpXNSvrLprVB3VTyh/3fBt1R8dK29bwvalj40aZS HDXWO2ADhm+RrWBPOJfqVLMsAXZVqqGzaiw3x/R3J/lLOL3VgP4tkhvy6kbdFjuoTq wzl+RGl/4ozFzzLB3FBmKAVemWyAm9xRiLUMhyv+ITRuQBqC/Gi0UQ4czuDZtUqcC9 zuL1gGZkMYofie0tY1QsgP5+SCzcVWWC3U+Wf36kQdh1WtsQRi8BtrifOj848mNFFT GFVnuUpREpAGnnpCWhMcE06z7TV1wqGJiir5XxDgzViCXQEO5ywBrM+9s4Pb2/+WYR Sxo0zhhqbK6eQ== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 11/17] kbuild: Add generic hook for architectures to use before the final vmlinux link Date: Sun, 14 Jul 2024 13:57:47 +0530 Message-ID: <87b71debd931011f8b9204c700b3084a6c3cdab8.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On powerpc, we would like to be able to make a pass on vmlinux.o and generate a new object file to be linked into vmlinux. Add a generic pass in Makefile.vmlinux that architectures can use for this purpose. Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must provide arch//tools/Makefile with .arch.vmlinux.o target, which will be invoked prior to the final vmlinux link step. Signed-off-by: Naveen N Rao --- arch/Kconfig | 6 ++++++ scripts/Makefile.vmlinux | 8 ++++++++ scripts/link-vmlinux.sh | 11 ++++++++--- 3 files changed, 22 insertions(+), 3 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 975dd22a2dbd..ef868ff8156a 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1643,4 +1643,10 @@ config CC_HAS_SANE_FUNCTION_ALIGNMENT config ARCH_NEED_CMPXCHG_1_EMU bool +config ARCH_WANTS_PRE_LINK_VMLINUX + def_bool n + help + An architecture can select this if it provides arch//tools/Makefile + with .arch.vmlinux.o target to be linked into vmlinux. + endmenu diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux index 49946cb96844..6410e0be7f52 100644 --- a/scripts/Makefile.vmlinux +++ b/scripts/Makefile.vmlinux @@ -22,6 +22,14 @@ targets += .vmlinux.export.o vmlinux: .vmlinux.export.o endif +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX +targets += .arch.vmlinux.o +.arch.vmlinux.o: vmlinux.o FORCE + $(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools .arch.vmlinux.o + +vmlinux: .arch.vmlinux.o +endif + ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink) # Final link of vmlinux with optional arch pass after final link diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 518c70b8db50..aafaed1412ea 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -122,7 +122,7 @@ gen_btf() return 1 fi - vmlinux_link ${1} + vmlinux_link ${1} ${arch_vmlinux_o} info "BTF" ${2} LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1} @@ -178,7 +178,7 @@ kallsyms_step() kallsymso=${kallsyms_vmlinux}.o kallsyms_S=${kallsyms_vmlinux}.S - vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o} + vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o} ${arch_vmlinux_o} mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms kallsyms ${kallsyms_vmlinux}.syms ${kallsyms_S} @@ -223,6 +223,11 @@ fi ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o +arch_vmlinux_o="" +if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then + arch_vmlinux_o=.arch.vmlinux.o +fi + btf_vmlinux_bin_o="" if is_enabled CONFIG_DEBUG_INFO_BTF; then btf_vmlinux_bin_o=.btf.vmlinux.bin.o @@ -273,7 +278,7 @@ if is_enabled CONFIG_KALLSYMS; then fi fi -vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} +vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} ${arch_vmlinux_o} # fill in BTF IDs if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then From patchwork Sun Jul 14 08:27:48 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732591 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3418A45978; Sun, 14 Jul 2024 08:29:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; 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Sun, 14 Jul 2024 08:29:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945743; bh=KBLljzJL81QppAo9x5KZ+GFQsO9P2fs5ywA9W+g/wm8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZXrTndfBng6nMj6KZ6cMOM9K0nhZ70rffIv6l2Uro/IPrupp2hJaWgWQI+lG1azD4 jWyNr5AvpNomzF4NCoBEUeP/wt9h53MNKh9DIWa9IRu1Swha9+mydK1iskEx7UbJAj klZjlpjak5HM/BLGbL7zHdhcZt6hyCSq16aRgkU1RqKOg8doq4RSKOcU4rpQvCgWnQ LUx13I/IOhd55bOajPCwPslA2osN8R+L0/a8nEv6giaJ5jYhkGPHluTUNgk2GpFPGC LoPUDcXzjxRR9Yk/1SCwbjTrtm0rMFCgQUklli3CFUaBCg7VkCsSIOUm2Q/lzpwGkk yyMIQksPEppXQ== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 12/17] powerpc64/ftrace: Move ftrace sequence out of line Date: Sun, 14 Jul 2024 13:57:48 +0530 Message-ID: <9cf2cdddba74ec167ae1af5ec189bba8f704fb51.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Function profile sequence on powerpc includes two instructions at the beginning of each function: mflr r0 bl ftrace_caller The call to ftrace_caller() gets nop'ed out during kernel boot and is patched in when ftrace is enabled. Given the sequence, we cannot return from ftrace_caller with 'blr' as we need to keep LR and r0 intact. This results in link stack (return address predictor) imbalance when ftrace is enabled. To address that, we would like to use a three instruction sequence: mflr r0 bl ftrace_caller mtlr r0 Further more, to support DYNAMIC_FTRACE_WITH_CALL_OPS, we need to reserve two instruction slots before the function. This results in a total of five instruction slots to be reserved for ftrace use on each function that is traced. Move the function profile sequence out-of-line to minimize its impact. To do this, we reserve a single nop at function entry using -fpatchable-function-entry=1 and add a pass on vmlinux.o to determine the total number of functions that can be traced. This is then used to generate a .S file reserving the appropriate amount of space for use as ftrace stubs, which is built and linked into vmlinux. On bootup, the stub space is split into separate stubs per function and populated with the proper instruction sequence. A pointer to the associated stub is maintained in dyn_arch_ftrace. For modules, space for ftrace stubs is reserved from the generic module stub space. This is restricted to and enabled by default only on 64-bit powerpc, though there are some changes to accommodate 32-bit powerpc. This is done so that 32-bit powerpc could choose to opt into this based on further tests and benchmarks. As an example, after this patch, kernel functions will have a single nop at function entry: : addis r2,r12,467 addi r2,r2,-16028 nop mfocrf r11,8 ... When ftrace is enabled, the nop is converted to an unconditional branch to the stub associated with that function: : addis r2,r12,467 addi r2,r2,-16028 b ftrace_ool_stub_text_end+0x11b28 mfocrf r11,8 ... The associated stub: : mflr r0 bl ftrace_caller mtlr r0 b kernel_clone+0xc ... Signed-off-by: Naveen N Rao --- arch/powerpc/Kconfig | 5 + arch/powerpc/Makefile | 4 + arch/powerpc/include/asm/ftrace.h | 11 ++ arch/powerpc/include/asm/module.h | 5 + arch/powerpc/kernel/asm-offsets.c | 4 + arch/powerpc/kernel/module_64.c | 58 +++++++- arch/powerpc/kernel/trace/ftrace.c | 157 +++++++++++++++++++-- arch/powerpc/kernel/trace/ftrace_entry.S | 116 +++++++++++---- arch/powerpc/tools/Makefile | 10 ++ arch/powerpc/tools/ftrace-gen-ool-stubs.sh | 48 +++++++ 10 files changed, 381 insertions(+), 37 deletions(-) create mode 100644 arch/powerpc/tools/Makefile create mode 100755 arch/powerpc/tools/ftrace-gen-ool-stubs.sh diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 68f0e7a5576f..f50cfd15bb73 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -568,6 +568,11 @@ config ARCH_USING_PATCHABLE_FUNCTION_ENTRY def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh $(CC) -mlittle-endian) if PPC64 && CPU_LITTLE_ENDIAN def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh $(CC) -mbig-endian) if PPC64 && CPU_BIG_ENDIAN +config PPC_FTRACE_OUT_OF_LINE + def_bool PPC64 && ARCH_USING_PATCHABLE_FUNCTION_ENTRY + depends on PPC64 + select ARCH_WANTS_PRE_LINK_VMLINUX + config HOTPLUG_CPU bool "Support for enabling/disabling CPUs" depends on SMP && (PPC_PSERIES || \ diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index bbfe4a1f06ef..c973e6cd1ae8 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -155,7 +155,11 @@ CC_FLAGS_NO_FPU := $(call cc-option,-msoft-float) ifdef CONFIG_FUNCTION_TRACER ifdef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY +ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +CC_FLAGS_FTRACE := -fpatchable-function-entry=1 +else CC_FLAGS_FTRACE := -fpatchable-function-entry=2 +endif else CC_FLAGS_FTRACE := -pg ifdef CONFIG_MPROFILE_KERNEL diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 201f9d15430a..0589bb252de7 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -26,6 +26,10 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, struct module; struct dyn_ftrace; struct dyn_arch_ftrace { +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + /* pointer to the associated out-of-line stub */ + unsigned long ool_stub; +#endif }; #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS @@ -132,6 +136,13 @@ static inline u8 this_cpu_get_ftrace_enabled(void) { return 1; } #ifdef CONFIG_FUNCTION_TRACER extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +struct ftrace_ool_stub { + u32 insn[4]; +}; +extern struct ftrace_ool_stub ftrace_ool_stub_text_end[], ftrace_ool_stub_inittext[]; +extern unsigned int ftrace_ool_stub_text_end_count, ftrace_ool_stub_inittext_count; +#endif void ftrace_free_init_tramp(void); unsigned long ftrace_call_adjust(unsigned long addr); #else diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h index 300c777cc307..9ee70a4a0fde 100644 --- a/arch/powerpc/include/asm/module.h +++ b/arch/powerpc/include/asm/module.h @@ -47,6 +47,11 @@ struct mod_arch_specific { #ifdef CONFIG_DYNAMIC_FTRACE unsigned long tramp; unsigned long tramp_regs; +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + struct ftrace_ool_stub *ool_stubs; + unsigned int ool_stub_count; + unsigned int ool_stub_index; +#endif #endif }; diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 23733282de4d..6854547d3164 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -674,5 +674,9 @@ int main(void) DEFINE(BPT_SIZE, BPT_SIZE); #endif +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + DEFINE(FTRACE_OOL_STUB_SIZE, sizeof(struct ftrace_ool_stub)); +#endif + return 0; } diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index 1db88409bd95..6816e9967cab 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c @@ -205,7 +205,9 @@ static int relacmp(const void *_x, const void *_y) /* Get size of potential trampolines required. */ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, - const Elf64_Shdr *sechdrs) + const Elf64_Shdr *sechdrs, + char *secstrings, + struct module *me) { /* One extra reloc so it's always 0-addr terminated */ unsigned long relocs = 1; @@ -244,6 +246,24 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, /* stubs for ftrace_caller and ftrace_regs_caller */ relocs += IS_ENABLED(CONFIG_DYNAMIC_FTRACE) + IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS); +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + /* stubs for the function tracer */ + for (i = 1; i < hdr->e_shnum; i++) { + if (!strcmp(secstrings + sechdrs[i].sh_name, "__patchable_function_entries")) { + me->arch.ool_stub_count = sechdrs[i].sh_size / sizeof(unsigned long); + me->arch.ool_stub_index = 0; + relocs += roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub), + sizeof(struct ppc64_stub_entry)) / + sizeof(struct ppc64_stub_entry); + break; + } + } + if (i == hdr->e_shnum) { + pr_err("%s: doesn't contain __patchable_function_entries.\n", me->name); + return -ENOEXEC; + } +#endif + pr_debug("Looks like a total of %lu stubs, max\n", relocs); return relocs * sizeof(struct ppc64_stub_entry); } @@ -454,7 +474,7 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr, #endif /* Override the stubs size */ - sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs); + sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs, secstrings, me); return 0; } @@ -1079,6 +1099,37 @@ int module_trampoline_target(struct module *mod, unsigned long addr, return 0; } +static int setup_ftrace_ool_stubs(const Elf64_Shdr *sechdrs, unsigned long addr, struct module *me) +{ +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + unsigned int i, total_stubs, num_stubs; + struct ppc64_stub_entry *stub; + + total_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stub); + num_stubs = roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub), + sizeof(struct ppc64_stub_entry)) / sizeof(struct ppc64_stub_entry); + + /* Find the next available entry */ + stub = (void *)sechdrs[me->arch.stubs_section].sh_addr; + for (i = 0; stub_func_addr(stub[i].funcdata); i++) + if (WARN_ON(i >= total_stubs)) + return -1; + + if (WARN_ON(i + num_stubs > total_stubs)) + return -1; + + stub += i; + me->arch.ool_stubs = (struct ftrace_ool_stub *)stub; + + /* reserve stubs */ + for (i = 0; i < num_stubs; i++) + if (patch_u32((void *)&stub->funcdata, PPC_RAW_NOP())) + return -1; +#endif + + return 0; +} + int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs) { mod->arch.tramp = stub_for_addr(sechdrs, @@ -1097,6 +1148,9 @@ int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs) if (!mod->arch.tramp) return -ENOENT; + if (setup_ftrace_ool_stubs(sechdrs, mod->arch.tramp, mod)) + return -ENOENT; + return 0; } #endif diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 719517265d39..c03336301bad 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -37,7 +37,8 @@ unsigned long ftrace_call_adjust(unsigned long addr) if (addr >= (unsigned long)__exittext_begin && addr < (unsigned long)__exittext_end) return 0; - if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) + if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) && + !IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) addr += MCOUNT_INSN_SIZE; return addr; @@ -127,11 +128,25 @@ static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long a } #endif +static unsigned long ftrace_get_ool_stub(struct dyn_ftrace *rec) +{ +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + return rec->arch.ool_stub; +#else + BUILD_BUG(); +#endif +} + static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_inst_t *call_inst) { - unsigned long ip = rec->ip; + unsigned long ip; unsigned long stub; + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; /* second instruction in stub */ + else + ip = rec->ip; + if (is_offset_in_branch_range(addr - ip)) /* Within range */ stub = addr; @@ -142,7 +157,7 @@ static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_ stub = ftrace_lookup_module_stub(ip, addr); if (!stub) { - pr_err("0x%lx: No ftrace stubs reachable\n", ip); + pr_err("0x%lx (0x%lx): No ftrace stubs reachable\n", ip, rec->ip); return -EINVAL; } @@ -150,6 +165,87 @@ static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_ return 0; } +static int ftrace_init_ool_stub(struct module *mod, struct dyn_ftrace *rec) +{ +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + static int ool_stub_text_end_index, ool_stub_inittext_index; + int ret = 0, ool_stub_count, *ool_stub_index; + ppc_inst_t inst; + /* + * See ftrace_entry.S if changing the below instruction sequence, as we rely on + * decoding the last branch instruction here to recover the correct function ip. + */ + struct ftrace_ool_stub *ool_stub, ool_stub_template = { + .insn = { + PPC_RAW_MFLR(_R0), + PPC_RAW_NOP(), /* bl ftrace_caller */ + PPC_RAW_MTLR(_R0), + PPC_RAW_NOP() /* b rec->ip + 4 */ + } + }; + + WARN_ON(rec->arch.ool_stub); + + if (is_kernel_inittext(rec->ip)) { + ool_stub = ftrace_ool_stub_inittext; + ool_stub_index = &ool_stub_inittext_index; + ool_stub_count = ftrace_ool_stub_inittext_count; + } else if (is_kernel_text(rec->ip)) { + ool_stub = ftrace_ool_stub_text_end; + ool_stub_index = &ool_stub_text_end_index; + ool_stub_count = ftrace_ool_stub_text_end_count; +#ifdef CONFIG_MODULES + } else if (mod) { + ool_stub = mod->arch.ool_stubs; + ool_stub_index = &mod->arch.ool_stub_index; + ool_stub_count = mod->arch.ool_stub_count; +#endif + } else { + return -EINVAL; + } + + ool_stub += (*ool_stub_index)++; + + if (WARN_ON(*ool_stub_index > ool_stub_count)) + return -EINVAL; + + if (!is_offset_in_branch_range((long)rec->ip - (long)&ool_stub->insn[0]) || + !is_offset_in_branch_range((long)(rec->ip + MCOUNT_INSN_SIZE) - (long)&ool_stub->insn[3])) { + pr_err("%s: ftrace ool stub out of range (%p -> %p).\n", + __func__, (void *)rec->ip, (void *)&ool_stub->insn[0]); + return -EINVAL; + } + + rec->arch.ool_stub = (unsigned long)&ool_stub->insn[0]; + + /* bl ftrace_caller */ + if (mod) + /* + * We can't use ftrace_get_call_inst() since that uses __module_text_address(rec->ip) + * to look up the module. But, since the module is not fully formed at this stage, + * the lookup fails. We know the target though, so generate the branch inst directly. + */ + inst = ftrace_create_branch_inst(ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE, + mod->arch.tramp, 1); + else + ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &inst); + ool_stub_template.insn[1] = ppc_inst_val(inst); + + /* b rec->ip + 4 */ + if (!ret && create_branch(&inst, &ool_stub->insn[3], rec->ip + MCOUNT_INSN_SIZE, 0)) + return -EINVAL; + ool_stub_template.insn[3] = ppc_inst_val(inst); + + if (!ret) + ret = patch_instructions((u32 *)ool_stub, (u32 *)&ool_stub_template, + sizeof(ool_stub_template), false); + + return ret; +#else /* !CONFIG_PPC_FTRACE_OUT_OF_LINE */ + BUILD_BUG(); +#endif +} + #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) { @@ -162,18 +258,29 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { ppc_inst_t old, new; - int ret; + unsigned long ip = rec->ip; + int ret = 0; /* This can only ever be called during module load */ - if (WARN_ON(!IS_ENABLED(CONFIG_MODULES) || core_kernel_text(rec->ip))) + if (WARN_ON(!IS_ENABLED(CONFIG_MODULES) || core_kernel_text(ip))) return -EINVAL; old = ppc_inst(PPC_RAW_NOP()); - ret = ftrace_get_call_inst(rec, addr, &new); - if (ret) - return ret; + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) { + ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; /* second instruction in stub */ + ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &old); + } - return ftrace_modify_code(rec->ip, old, new); + ret |= ftrace_get_call_inst(rec, addr, &new); + + if (!ret) + ret = ftrace_modify_code(ip, old, new); + + if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + ret = ftrace_modify_code(rec->ip, ppc_inst(PPC_RAW_NOP()), + ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) - (long)rec->ip))); + + return ret; } int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) @@ -206,6 +313,13 @@ void ftrace_replace_code(int enable) new_addr = ftrace_get_addr_new(rec); update = ftrace_update_record(rec, enable); + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) && update != FTRACE_UPDATE_IGNORE) { + ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; + ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &nop_inst); + if (ret) + goto out; + } + switch (update) { case FTRACE_UPDATE_IGNORE: default: @@ -230,6 +344,24 @@ void ftrace_replace_code(int enable) if (!ret) ret = ftrace_modify_code(ip, old, new); + + if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) && + (update == FTRACE_UPDATE_MAKE_NOP || update == FTRACE_UPDATE_MAKE_CALL)) { + /* Update the actual ftrace location */ + call_inst = ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) - + (long)rec->ip)); + nop_inst = ppc_inst(PPC_RAW_NOP()); + ip = rec->ip; + + if (update == FTRACE_UPDATE_MAKE_NOP) + ret = ftrace_modify_code(ip, call_inst, nop_inst); + else + ret = ftrace_modify_code(ip, nop_inst, call_inst); + + if (ret) + goto out; + } + if (ret) goto out; } @@ -249,7 +381,8 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) /* Verify instructions surrounding the ftrace location */ if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) { /* Expect nops */ - ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_NOP())); + if (!IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_NOP())); if (!ret) ret = ftrace_validate_inst(ip, ppc_inst(PPC_RAW_NOP())); } else if (IS_ENABLED(CONFIG_PPC32)) { @@ -277,6 +410,10 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) if (ret) return ret; + /* Set up out-of-line stub */ + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + return ftrace_init_ool_stub(mod, rec); + /* Nop-out the ftrace location */ new = ppc_inst(PPC_RAW_NOP()); addr = MCOUNT_ADDR; diff --git a/arch/powerpc/kernel/trace/ftrace_entry.S b/arch/powerpc/kernel/trace/ftrace_entry.S index 244a1c7bb1e8..71f6a63cd861 100644 --- a/arch/powerpc/kernel/trace/ftrace_entry.S +++ b/arch/powerpc/kernel/trace/ftrace_entry.S @@ -56,7 +56,7 @@ SAVE_GPR(2, r1) SAVE_GPRS(11, 31, r1) .else -#ifdef CONFIG_LIVEPATCH_64 +#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE) SAVE_GPR(14, r1) #endif .endif @@ -78,10 +78,6 @@ /* Get the _mcount() call site out of LR */ mflr r7 - /* Save it as pt_regs->nip */ - PPC_STL r7, _NIP(r1) - /* Also save it in B's stackframe header for proper unwind */ - PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) /* Save the read LR in pt_regs->link */ PPC_STL r0, _LINK(r1) @@ -96,16 +92,6 @@ lwz r5,function_trace_op@l(r3) #endif -#ifdef CONFIG_LIVEPATCH_64 - mr r14, r7 /* remember old NIP */ -#endif - - /* Calculate ip from nip-4 into r3 for call below */ - subi r3, r7, MCOUNT_INSN_SIZE - - /* Put the original return address in r4 as parent_ip */ - mr r4, r0 - /* Save special regs */ PPC_STL r8, _MSR(r1) .if \allregs == 1 @@ -114,17 +100,69 @@ PPC_STL r11, _CCR(r1) .endif +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + /* Save our real return address in nvr for return */ + .if \allregs == 0 + SAVE_GPR(15, r1) + .endif + mr r15, r7 + /* + * We want the ftrace location in the function, but our lr (in r7) + * points at the 'mtlr r0' instruction in the out of line stub. To + * recover the ftrace location, we read the branch instruction in the + * stub, and adjust our lr by the branch offset. + * + * See ftrace_init_ool_stub() for the profile sequence. + */ + lwz r8, MCOUNT_INSN_SIZE(r7) + slwi r8, r8, 6 + srawi r8, r8, 6 + add r3, r7, r8 + /* + * Override our nip to point past the branch in the original function. + * This allows reliable stack trace and the ftrace stack tracer to work as-is. + */ + add r7, r3, MCOUNT_INSN_SIZE +#else + /* Calculate ip from nip-4 into r3 for call below */ + subi r3, r7, MCOUNT_INSN_SIZE +#endif + + /* Save NIP as pt_regs->nip */ + PPC_STL r7, _NIP(r1) + /* Also save it in B's stackframe header for proper unwind */ + PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) +#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE) + mr r14, r7 /* remember old NIP */ +#endif + + /* Put the original return address in r4 as parent_ip */ + mr r4, r0 + /* Load &pt_regs in r6 for call below */ addi r6, r1, STACK_INT_FRAME_REGS .endm .macro ftrace_regs_exit allregs +#ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE /* Load ctr with the possibly modified NIP */ PPC_LL r3, _NIP(r1) mtctr r3 #ifdef CONFIG_LIVEPATCH_64 cmpd r14, r3 /* has NIP been altered? */ +#endif +#else /* !CONFIG_PPC_FTRACE_OUT_OF_LINE */ + /* Load LR with the possibly modified NIP */ + PPC_LL r3, _NIP(r1) + cmpd r14, r3 /* has NIP been altered? */ + bne- 1f + + mr r3, r15 + .if \allregs == 0 + REST_GPR(15, r1) + .endif +1: mtlr r3 #endif /* Restore gprs */ @@ -132,14 +170,16 @@ REST_GPRS(2, 31, r1) .else REST_GPRS(3, 10, r1) -#ifdef CONFIG_LIVEPATCH_64 +#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE) REST_GPR(14, r1) #endif .endif /* Restore possibly modified LR */ PPC_LL r0, _LINK(r1) +#ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE mtlr r0 +#endif #ifdef CONFIG_PPC64 /* Restore callee's TOC */ @@ -153,7 +193,16 @@ /* Based on the cmpd above, if the NIP was altered handle livepatch */ bne- livepatch_handler #endif - bctr /* jump after _mcount site */ + /* jump after _mcount site */ +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + /* + * Return with blr to keep the link stack balanced. The function profiling sequence + * uses 'mtlr r0' to restore LR. + */ + blr +#else + bctr +#endif .endm _GLOBAL(ftrace_regs_caller) @@ -177,6 +226,11 @@ _GLOBAL(ftrace_stub) #ifdef CONFIG_PPC64 ftrace_no_trace: +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE + REST_GPR(3, r1) + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE + blr +#else mflr r3 mtctr r3 REST_GPR(3, r1) @@ -184,6 +238,7 @@ ftrace_no_trace: mtlr r0 bctr #endif +#endif #ifdef CONFIG_LIVEPATCH_64 /* @@ -194,11 +249,17 @@ ftrace_no_trace: * We get here when a function A, calls another function B, but B has * been live patched with a new function C. * - * On entry: - * - we have no stack frame and can not allocate one + * On entry, we have no stack frame and can not allocate one. + * + * With PPC_FTRACE_OUT_OF_LINE=n, on entry: * - LR points back to the original caller (in A) * - CTR holds the new NIP in C * - r0, r11 & r12 are free + * + * With PPC_FTRACE_OUT_OF_LINE=y, on entry: + * - r0 points back to the original caller (in A) + * - LR holds the new NIP in C + * - r11 & r12 are free */ livepatch_handler: ld r12, PACA_THREAD_INFO(r13) @@ -208,18 +269,23 @@ livepatch_handler: addi r11, r11, 24 std r11, TI_livepatch_sp(r12) - /* Save toc & real LR on livepatch stack */ - std r2, -24(r11) - mflr r12 - std r12, -16(r11) - /* Store stack end marker */ lis r12, STACK_END_MAGIC@h ori r12, r12, STACK_END_MAGIC@l std r12, -8(r11) - /* Put ctr in r12 for global entry and branch there */ + /* Save toc & real LR on livepatch stack */ + std r2, -24(r11) +#ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE + mflr r12 + std r12, -16(r11) mfctr r12 +#else + std r0, -16(r11) + mflr r12 + /* Put ctr in r12 for global entry and branch there */ + mtctr r12 +#endif bctrl /* diff --git a/arch/powerpc/tools/Makefile b/arch/powerpc/tools/Makefile new file mode 100644 index 000000000000..31dd3151c272 --- /dev/null +++ b/arch/powerpc/tools/Makefile @@ -0,0 +1,10 @@ +# SPDX-License-Identifier: GPL-2.0-or-later + +quiet_cmd_gen_ftrace_ool_stubs = FTRACE $@ + cmd_gen_ftrace_ool_stubs = $< $(objtree)/vmlinux.o $@ + +targets += .arch.vmlinux.o +.arch.vmlinux.o: $(srctree)/arch/powerpc/tools/ftrace-gen-ool-stubs.sh $(objtree)/vmlinux.o FORCE + $(call if_changed,gen_ftrace_ool_stubs) + +clean-files += $(objtree)/.arch.vmlinux.S $(objtree)/.arch.vmlinux.o diff --git a/arch/powerpc/tools/ftrace-gen-ool-stubs.sh b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh new file mode 100755 index 000000000000..0b85cd5262ff --- /dev/null +++ b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh @@ -0,0 +1,48 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later + +# Error out on error +set -e + +is_enabled() { + grep -q "^$1=y" include/config/auto.conf +} + +vmlinux_o=${1} +arch_vmlinux_o=${2} +arch_vmlinux_S=$(dirname ${arch_vmlinux_o})/$(basename ${arch_vmlinux_o} .o).S + +RELOCATION=R_PPC64_ADDR64 +if is_enabled CONFIG_PPC32; then + RELOCATION=R_PPC_ADDR32 +fi + +num_ool_stubs_text=$(${CROSS_COMPILE}objdump -r -j __patchable_function_entries ${vmlinux_o} | + grep -v ".init.text" | grep "${RELOCATION}" | wc -l) +num_ool_stubs_inittext=$(${CROSS_COMPILE}objdump -r -j __patchable_function_entries ${vmlinux_o} | + grep ".init.text" | grep "${RELOCATION}" | wc -l) + +cat > ${arch_vmlinux_S} < +#include + +.pushsection .tramp.ftrace.text,"aw" +SYM_DATA(ftrace_ool_stub_text_end_count, .long ${num_ool_stubs_text}) + +SYM_CODE_START(ftrace_ool_stub_text_end) + .space ${num_ool_stubs_text} * FTRACE_OOL_STUB_SIZE +SYM_CODE_END(ftrace_ool_stub_text_end) +.popsection + +.pushsection .tramp.ftrace.init,"aw" +SYM_DATA(ftrace_ool_stub_inittext_count, .long ${num_ool_stubs_inittext}) + +SYM_CODE_START(ftrace_ool_stub_inittext) + .space ${num_ool_stubs_inittext} * FTRACE_OOL_STUB_SIZE +SYM_CODE_END(ftrace_ool_stub_inittext) +.popsection +EOF + +${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \ + ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ + -c -o ${arch_vmlinux_o} ${arch_vmlinux_S} From patchwork Sun Jul 14 08:27:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732592 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B88471F94C; Sun, 14 Jul 2024 08:29:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945747; cv=none; b=jN9+gvlMNxAiPWxBo0/51MTQfeCVWKTLNDePobyt6pEFh5XrUVllSKMGYHY5B2wwyRQ6BLYSvARON9NG1dtiG1J0RH4mv2cXKo+tEVg/5qCQRd0frepp/hMVBgnMw9sot8bqaOACPPnPFs2HBBiz2cqnWOCWueh65FckZNwiqFY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945747; c=relaxed/simple; bh=xWhgEBXMpuHzX4bP2wz6NbJAdg0K/TnaR2I0FkU8uYU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iB/lsQBfwpgj5Oiu+RrRdHdRQZNNItMHXL4UI2WOaSpHhnrKZCIe6UD5SROhhAaoK4k0pP+vsotS+b3fYrML6KCQDx9jQjycnOL6QTSCgQAh/Mt/uA9sl7tq8uhUWsc9yWBNjN3JNHOf0tVsJVbvTemHx4j3Ne0cJ6gZFDL3Iks= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H3FJrbjL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="H3FJrbjL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87BBAC116B1; Sun, 14 Jul 2024 08:29:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945747; bh=xWhgEBXMpuHzX4bP2wz6NbJAdg0K/TnaR2I0FkU8uYU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H3FJrbjLJ8QL2Bi96EsUfVgQL/UxK78P+a2e08yZOj77S+XIa2ilGGUtm37+u55t/ z1/XeNTC/UlRP7EyLMXhqSkquLwNosbqMn+Oi7Y66wa4HG0WrMyzgygnMnQyXmzu4V OjBuB3Y/EgAga51wEiAFMHX7A4dn7IldDnq+dqUjGyxWNW+0kwV5sp6YvirsAUQz0A PZQD6pClmxoI4U7bC+HdHKyiHQ6iwLEFd5MQr7wcGNWezI99UcQRyv/VviiXDyNB8D F4tgIf+Jw2y06TR2BIseCxJXAwu94IPvZJyUF37izOT+asa6cyr6VtqLop+1hekeAn 2t8aAH97U5JzQ== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 13/17] powerpc64/ftrace: Support .text larger than 32MB with out-of-line stubs Date: Sun, 14 Jul 2024 13:57:49 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 We are restricted to a .text size of ~32MB when using out-of-line function profile sequence. Allow this to be extended up to the previous limit of ~64MB by reserving space in the middle of .text. A new config option CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE is introduced to specify the number of function stubs that are reserved in .text. On boot, ftrace utilizes stubs from this area first before using the stub area at the end of .text. A ppc64le defconfig has ~44k functions that can be traced. A more conservative value of 32k functions is chosen as the default value of PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE so that we do not allot more space than necessary by default. If building a kernel that only has 32k trace-able functions, we won't allot any more space at the end of .text during the pass on vmlinux.o. Otherwise, only the remaining functions get space for stubs at the end of .text. This default value should help cover a .text size of ~48MB in total (including space reserved at the end of .text which can cover up to 32MB), which should be sufficient for most common builds. For a very small kernel build, this can be set to 0. Or, this can be bumped up to a larger value to support vmlinux .text size up to ~64MB. Signed-off-by: Naveen N Rao --- arch/powerpc/Kconfig | 12 ++++++++++++ arch/powerpc/include/asm/ftrace.h | 6 ++++-- arch/powerpc/kernel/trace/ftrace.c | 21 +++++++++++++++++---- arch/powerpc/kernel/trace/ftrace_entry.S | 8 ++++++++ arch/powerpc/tools/Makefile | 2 +- arch/powerpc/tools/ftrace-gen-ool-stubs.sh | 11 +++++++---- 6 files changed, 49 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index f50cfd15bb73..a4dff8624510 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -573,6 +573,18 @@ config PPC_FTRACE_OUT_OF_LINE depends on PPC64 select ARCH_WANTS_PRE_LINK_VMLINUX +config PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE + int "Number of ftrace out-of-line stubs to reserve within .text" + default 32768 if PPC_FTRACE_OUT_OF_LINE + default 0 + help + Number of stubs to reserve for use by ftrace. This space is + reserved within .text, and is distinct from any additional space + added at the end of .text before the final vmlinux link. Set to + zero to have stubs only be generated at the end of vmlinux (only + if the size of vmlinux is less than 32MB). Set to a higher value + if building vmlinux larger than 48MB. + config HOTPLUG_CPU bool "Support for enabling/disabling CPUs" depends on SMP && (PPC_PSERIES || \ diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 0589bb252de7..dc870824359c 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -140,8 +140,10 @@ extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; struct ftrace_ool_stub { u32 insn[4]; }; -extern struct ftrace_ool_stub ftrace_ool_stub_text_end[], ftrace_ool_stub_inittext[]; -extern unsigned int ftrace_ool_stub_text_end_count, ftrace_ool_stub_inittext_count; +extern struct ftrace_ool_stub ftrace_ool_stub_text_end[], ftrace_ool_stub_text[], + ftrace_ool_stub_inittext[]; +extern unsigned int ftrace_ool_stub_text_end_count, ftrace_ool_stub_text_count, + ftrace_ool_stub_inittext_count; #endif void ftrace_free_init_tramp(void); unsigned long ftrace_call_adjust(unsigned long addr); diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index c03336301bad..b4de8b8cbe3a 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -168,7 +168,7 @@ static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_ static int ftrace_init_ool_stub(struct module *mod, struct dyn_ftrace *rec) { #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE - static int ool_stub_text_end_index, ool_stub_inittext_index; + static int ool_stub_text_index, ool_stub_text_end_index, ool_stub_inittext_index; int ret = 0, ool_stub_count, *ool_stub_index; ppc_inst_t inst; /* @@ -191,9 +191,22 @@ static int ftrace_init_ool_stub(struct module *mod, struct dyn_ftrace *rec) ool_stub_index = &ool_stub_inittext_index; ool_stub_count = ftrace_ool_stub_inittext_count; } else if (is_kernel_text(rec->ip)) { - ool_stub = ftrace_ool_stub_text_end; - ool_stub_index = &ool_stub_text_end_index; - ool_stub_count = ftrace_ool_stub_text_end_count; + /* + * ftrace records are sorted, so we first use up the stub area within .text + * (ftrace_ool_stub_text) before using the area at the end of .text + * (ftrace_ool_stub_text_end), unless the stub is out of range of the record. + */ + if (ool_stub_text_index >= ftrace_ool_stub_text_count || + !is_offset_in_branch_range((long)rec->ip - + (long)&ftrace_ool_stub_text[ool_stub_text_index])) { + ool_stub = ftrace_ool_stub_text_end; + ool_stub_index = &ool_stub_text_end_index; + ool_stub_count = ftrace_ool_stub_text_end_count; + } else { + ool_stub = ftrace_ool_stub_text; + ool_stub_index = &ool_stub_text_index; + ool_stub_count = ftrace_ool_stub_text_count; + } #ifdef CONFIG_MODULES } else if (mod) { ool_stub = mod->arch.ool_stubs; diff --git a/arch/powerpc/kernel/trace/ftrace_entry.S b/arch/powerpc/kernel/trace/ftrace_entry.S index 71f6a63cd861..86dbaa87532a 100644 --- a/arch/powerpc/kernel/trace/ftrace_entry.S +++ b/arch/powerpc/kernel/trace/ftrace_entry.S @@ -374,6 +374,14 @@ _GLOBAL(return_to_handler) blr #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +SYM_DATA(ftrace_ool_stub_text_count, .long CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE) + +SYM_CODE_START(ftrace_ool_stub_text) + .space CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE * FTRACE_OOL_STUB_SIZE +SYM_CODE_END(ftrace_ool_stub_text) +#endif + .pushsection ".tramp.ftrace.text","aw",@progbits; .globl ftrace_tramp_text ftrace_tramp_text: diff --git a/arch/powerpc/tools/Makefile b/arch/powerpc/tools/Makefile index 31dd3151c272..0ade63981aea 100644 --- a/arch/powerpc/tools/Makefile +++ b/arch/powerpc/tools/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-or-later quiet_cmd_gen_ftrace_ool_stubs = FTRACE $@ - cmd_gen_ftrace_ool_stubs = $< $(objtree)/vmlinux.o $@ + cmd_gen_ftrace_ool_stubs = $< $(CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE) $(objtree)/vmlinux.o $@ targets += .arch.vmlinux.o .arch.vmlinux.o: $(srctree)/arch/powerpc/tools/ftrace-gen-ool-stubs.sh $(objtree)/vmlinux.o FORCE diff --git a/arch/powerpc/tools/ftrace-gen-ool-stubs.sh b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh index 0b85cd5262ff..0d83adce4f23 100755 --- a/arch/powerpc/tools/ftrace-gen-ool-stubs.sh +++ b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh @@ -8,8 +8,8 @@ is_enabled() { grep -q "^$1=y" include/config/auto.conf } -vmlinux_o=${1} -arch_vmlinux_o=${2} +vmlinux_o=${2} +arch_vmlinux_o=${3} arch_vmlinux_S=$(dirname ${arch_vmlinux_o})/$(basename ${arch_vmlinux_o} .o).S RELOCATION=R_PPC64_ADDR64 @@ -22,15 +22,18 @@ num_ool_stubs_text=$(${CROSS_COMPILE}objdump -r -j __patchable_function_entries num_ool_stubs_inittext=$(${CROSS_COMPILE}objdump -r -j __patchable_function_entries ${vmlinux_o} | grep ".init.text" | grep "${RELOCATION}" | wc -l) +num_ool_stubs_text_builtin=${1} +num_ool_stubs_text_end=$(expr ${num_ool_stubs_text} - ${num_ool_stubs_text_builtin}) + cat > ${arch_vmlinux_S} < #include .pushsection .tramp.ftrace.text,"aw" -SYM_DATA(ftrace_ool_stub_text_end_count, .long ${num_ool_stubs_text}) +SYM_DATA(ftrace_ool_stub_text_end_count, .long ${num_ool_stubs_text_end}) SYM_CODE_START(ftrace_ool_stub_text_end) - .space ${num_ool_stubs_text} * FTRACE_OOL_STUB_SIZE + .space ${num_ool_stubs_text_end} * FTRACE_OOL_STUB_SIZE SYM_CODE_END(ftrace_ool_stub_text_end) .popsection From patchwork Sun Jul 14 08:27:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732593 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 26ADC61FE8; Sun, 14 Jul 2024 08:29:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945752; cv=none; b=V3iRMZU6pUNdokK9YC6EE8YH9UHFtg+BvIiuvxW3e29mMni+OQYkVeFYcN1ycfyyRCEJKuGtJA9atPukwClXP0/wgimIX2HPCigse9UNCFadqcluR/sqkvMVZU/3WdpDVy+zRFyPuL+rfpd4jIBggj4QRjP+WXfuUVhUH6AIyBk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945752; c=relaxed/simple; bh=E2no4Zp3K6euemkcPehXBmy3MKfeXPUlbvsZrHMrbEo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X1pU3edgLec4ZSsRi2JPQwpLy2Uv+9L1+n+OISoA59s94esb3VehVYQilZ1mZlfy3BsfzVY9OrDJJyPcg6FzfJzv0H5m8VPwnRTXqbOTCsCIZsctX87CRYDV5BrkmFn00IiDKE851coBJ8plNY/jz7pU12MRR3GerdR2UklYH34= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MZ/tNqhg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MZ/tNqhg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA9B4C116B1; Sun, 14 Jul 2024 08:29:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945751; bh=E2no4Zp3K6euemkcPehXBmy3MKfeXPUlbvsZrHMrbEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MZ/tNqhgIAUbzH8cztA+WspM7qA/F3XcrXWCSmI9iWvztkn7jrFBzBddQ8ztluMP3 kcvA8UgIzMwWOYCP8Kav3y/XtOQ24PK3HTKBkJKwM4YLjLdawdS1tb2wGeyVhJkuI0 4USz0tX0Pr+DowadroB4cS/+b8baeWSvXsU5HkEF/OHKWNNHC9KpyrVkVdY9ZYaiLF UrUQ6ORpGTK3S5LeX5hlVjIHHDE38bfLDwNTE8jtQaEBOPXAbpN9MCbMn+xeg/eCJk MiHM1fysB8tNcLGTJX8YZLqD4nUN5Occ9rKZo5lgX32Tb8hS98DEgc0rzLLgQ49yRS 7jNoVu5jSSEcQ== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 14/17] powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_CALL_OPS Date: Sun, 14 Jul 2024 13:57:50 +0530 Message-ID: <0e7a1344724c90c03834db1a246c78a1ea29c28b.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement support for DYNAMIC_FTRACE_WITH_CALL_OPS similar to the arm64 implementation. This works by patching-in a pointer to an associated ftrace_ops structure before each traceable function. If multiple ftrace_ops are associated with a call site, then a special ftrace_list_ops is used to enable iterating over all the registered ftrace_ops. If no ftrace_ops are associated with a call site, then a special ftrace_nop_ops structure is used to render the ftrace call as a no-op. ftrace trampoline can then read the associated ftrace_ops for a call site by loading from an offset from the LR, and branch directly to the associated function. The primary advantage with this approach is that we don't have to iterate over all the registered ftrace_ops for call sites that have a single ftrace_ops registered. This is the equivalent of implementing support for dynamic ftrace trampolines, which set up a special ftrace trampoline for each registered ftrace_ops and have individual call sites branch into those directly. A secondary advantage is that this gives us a way to add support for direct ftrace callers without having to resort to using stubs. The address of the direct call trampoline can be loaded from the ftrace_ops structure. To support this, we reserve a nop before each function on 32-bit powerpc. For 64-bit powerpc, two nops are reserved before each out-of-line stub. During ftrace activation, we update this location with the associated ftrace_ops pointer. Then, on ftrace entry, we load from this location and call into ftrace_ops->func(). For 64-bit powerpc, we ensure that the out-of-line stub area is doubleword aligned so that ftrace_ops address can be updated atomically. Signed-off-by: Naveen N Rao --- arch/powerpc/Kconfig | 1 + arch/powerpc/Makefile | 4 ++ arch/powerpc/include/asm/ftrace.h | 5 +- arch/powerpc/kernel/asm-offsets.c | 4 ++ arch/powerpc/kernel/trace/ftrace.c | 59 +++++++++++++++++++++- arch/powerpc/kernel/trace/ftrace_entry.S | 36 ++++++++++--- arch/powerpc/tools/ftrace-gen-ool-stubs.sh | 5 +- 7 files changed, 102 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index a4dff8624510..cb6031d86dc9 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -235,6 +235,7 @@ config PPC select HAVE_DEBUG_STACKOVERFLOW select HAVE_DYNAMIC_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_ARGS if ARCH_USING_PATCHABLE_FUNCTION_ENTRY || MPROFILE_KERNEL || PPC32 + select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS if PPC_FTRACE_OUT_OF_LINE || (PPC32 && ARCH_USING_PATCHABLE_FUNCTION_ENTRY) select HAVE_DYNAMIC_FTRACE_WITH_REGS if ARCH_USING_PATCHABLE_FUNCTION_ENTRY || MPROFILE_KERNEL || PPC32 select HAVE_EBPF_JIT select HAVE_EFFICIENT_UNALIGNED_ACCESS diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index c973e6cd1ae8..7dede0ec0163 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -158,8 +158,12 @@ KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE CC_FLAGS_FTRACE := -fpatchable-function-entry=1 else +ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS # PPC32 only +CC_FLAGS_FTRACE := -fpatchable-function-entry=3,1 +else CC_FLAGS_FTRACE := -fpatchable-function-entry=2 endif +endif else CC_FLAGS_FTRACE := -pg ifdef CONFIG_MPROFILE_KERNEL diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index dc870824359c..267bd52fef21 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -138,8 +138,11 @@ static inline u8 this_cpu_get_ftrace_enabled(void) { return 1; } extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE struct ftrace_ool_stub { +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS + struct ftrace_ops *ftrace_op; +#endif u32 insn[4]; -}; +} __aligned(sizeof(unsigned long)); extern struct ftrace_ool_stub ftrace_ool_stub_text_end[], ftrace_ool_stub_text[], ftrace_ool_stub_inittext[]; extern unsigned int ftrace_ool_stub_text_end_count, ftrace_ool_stub_text_count, diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 6854547d3164..60d1e388c2ba 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -678,5 +678,9 @@ int main(void) DEFINE(FTRACE_OOL_STUB_SIZE, sizeof(struct ftrace_ool_stub)); #endif +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS + OFFSET(FTRACE_OPS_FUNC, ftrace_ops, func); +#endif + return 0; } diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index b4de8b8cbe3a..291c6c3d3a78 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -38,8 +38,11 @@ unsigned long ftrace_call_adjust(unsigned long addr) return 0; if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) && - !IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + !IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) { addr += MCOUNT_INSN_SIZE; + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS)) + addr += MCOUNT_INSN_SIZE; + } return addr; } @@ -259,6 +262,46 @@ static int ftrace_init_ool_stub(struct module *mod, struct dyn_ftrace *rec) #endif } +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS +static const struct ftrace_ops *powerpc_rec_get_ops(struct dyn_ftrace *rec) +{ + const struct ftrace_ops *ops = NULL; + + if (rec->flags & FTRACE_FL_CALL_OPS_EN) { + ops = ftrace_find_unique_ops(rec); + WARN_ON_ONCE(!ops); + } + + if (!ops) + ops = &ftrace_list_ops; + + return ops; +} + +static int ftrace_rec_set_ops(struct dyn_ftrace *rec, const struct ftrace_ops *ops) +{ + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + return patch_ulong((void *)(ftrace_get_ool_stub(rec) - sizeof(unsigned long)), + (unsigned long)ops); + else + return patch_ulong((void *)(rec->ip - MCOUNT_INSN_SIZE - sizeof(unsigned long)), + (unsigned long)ops); +} + +static int ftrace_rec_set_nop_ops(struct dyn_ftrace *rec) +{ + return ftrace_rec_set_ops(rec, &ftrace_nop_ops); +} + +static int ftrace_rec_update_ops(struct dyn_ftrace *rec) +{ + return ftrace_rec_set_ops(rec, powerpc_rec_get_ops(rec)); +} +#else +static int ftrace_rec_set_nop_ops(struct dyn_ftrace *rec) { return 0; } +static int ftrace_rec_update_ops(struct dyn_ftrace *rec) { return 0; } +#endif + #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) { @@ -289,6 +332,10 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) if (!ret) ret = ftrace_modify_code(ip, old, new); + ret = ftrace_rec_update_ops(rec); + if (ret) + return ret; + if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) ret = ftrace_modify_code(rec->ip, ppc_inst(PPC_RAW_NOP()), ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) - (long)rec->ip))); @@ -340,16 +387,19 @@ void ftrace_replace_code(int enable) case FTRACE_UPDATE_MODIFY_CALL: ret = ftrace_get_call_inst(rec, new_addr, &new_call_inst); ret |= ftrace_get_call_inst(rec, addr, &call_inst); + ret |= ftrace_rec_update_ops(rec); old = call_inst; new = new_call_inst; break; case FTRACE_UPDATE_MAKE_NOP: ret = ftrace_get_call_inst(rec, addr, &call_inst); + ret |= ftrace_rec_set_nop_ops(rec); old = call_inst; new = nop_inst; break; case FTRACE_UPDATE_MAKE_CALL: ret = ftrace_get_call_inst(rec, new_addr, &call_inst); + ret |= ftrace_rec_update_ops(rec); old = nop_inst; new = call_inst; break; @@ -465,6 +515,13 @@ int ftrace_update_ftrace_func(ftrace_func_t func) ppc_inst_t old, new; int ret; + /* + * When using CALL_OPS, the function to call is associated with the + * call site, and we don't have a global function pointer to update. + */ + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS)) + return 0; + old = ppc_inst_read((u32 *)&ftrace_call); new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1); ret = ftrace_modify_code(ip, old, new); diff --git a/arch/powerpc/kernel/trace/ftrace_entry.S b/arch/powerpc/kernel/trace/ftrace_entry.S index 86dbaa87532a..c019380bdd6a 100644 --- a/arch/powerpc/kernel/trace/ftrace_entry.S +++ b/arch/powerpc/kernel/trace/ftrace_entry.S @@ -85,11 +85,21 @@ /* Save callee's TOC in the ABI compliant location */ std r2, STK_GOT(r1) LOAD_PACA_TOC() /* get kernel TOC in r2 */ +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS + /* r7 points to the instruction following the call to ftrace */ + PPC_LL r5, -(MCOUNT_INSN_SIZE*2 + SZL)(r7) + PPC_LL r12, FTRACE_OPS_FUNC(r5) + mtctr r12 +#else /* !CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS */ +#ifdef CONFIG_PPC64 LOAD_REG_ADDR(r3, function_trace_op) ld r5,0(r3) #else lis r3,function_trace_op@ha lwz r5,function_trace_op@l(r3) +#endif #endif /* Save special regs */ @@ -205,20 +215,30 @@ #endif .endm -_GLOBAL(ftrace_regs_caller) - ftrace_regs_entry 1 - /* ftrace_call(r3, r4, r5, r6) */ +.macro ftrace_regs_func allregs +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS + bctrl +#else + .if \allregs == 1 .globl ftrace_regs_call ftrace_regs_call: + .else +.globl ftrace_call +ftrace_call: + .endif + /* ftrace_call(r3, r4, r5, r6) */ bl ftrace_stub +#endif +.endm + +_GLOBAL(ftrace_regs_caller) + ftrace_regs_entry 1 + ftrace_regs_func 1 ftrace_regs_exit 1 _GLOBAL(ftrace_caller) ftrace_regs_entry 0 - /* ftrace_call(r3, r4, r5, r6) */ -.globl ftrace_call -ftrace_call: - bl ftrace_stub + ftrace_regs_func 0 ftrace_regs_exit 0 _GLOBAL(ftrace_stub) @@ -377,7 +397,7 @@ _GLOBAL(return_to_handler) #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE SYM_DATA(ftrace_ool_stub_text_count, .long CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE) -SYM_CODE_START(ftrace_ool_stub_text) +SYM_START(ftrace_ool_stub_text, SYM_L_GLOBAL, .balign SZL) .space CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE * FTRACE_OOL_STUB_SIZE SYM_CODE_END(ftrace_ool_stub_text) #endif diff --git a/arch/powerpc/tools/ftrace-gen-ool-stubs.sh b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh index 0d83adce4f23..a8dc26e10e66 100755 --- a/arch/powerpc/tools/ftrace-gen-ool-stubs.sh +++ b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh @@ -27,12 +27,13 @@ num_ool_stubs_text_end=$(expr ${num_ool_stubs_text} - ${num_ool_stubs_text_built cat > ${arch_vmlinux_S} < +#include #include .pushsection .tramp.ftrace.text,"aw" SYM_DATA(ftrace_ool_stub_text_end_count, .long ${num_ool_stubs_text_end}) -SYM_CODE_START(ftrace_ool_stub_text_end) +SYM_START(ftrace_ool_stub_text_end, SYM_L_GLOBAL, .balign SZL) .space ${num_ool_stubs_text_end} * FTRACE_OOL_STUB_SIZE SYM_CODE_END(ftrace_ool_stub_text_end) .popsection @@ -40,7 +41,7 @@ SYM_CODE_END(ftrace_ool_stub_text_end) .pushsection .tramp.ftrace.init,"aw" SYM_DATA(ftrace_ool_stub_inittext_count, .long ${num_ool_stubs_inittext}) -SYM_CODE_START(ftrace_ool_stub_inittext) +SYM_START(ftrace_ool_stub_inittext, SYM_L_GLOBAL, .balign SZL) .space ${num_ool_stubs_inittext} * FTRACE_OOL_STUB_SIZE SYM_CODE_END(ftrace_ool_stub_inittext) .popsection From patchwork Sun Jul 14 08:27:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732594 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4251B7173C; Sun, 14 Jul 2024 08:29:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945756; cv=none; b=c5xmoT2FogTdK5X4GTCNM1Uq0KskbvKryz+FANGZGKopCgIa/i1UBxAW1qzbUEnuiuou86rkudHn7qK8EmQJZBGeRhRUICr2WmAMab+pAfarb998m5AfP3Qx16J1om0gDmriAXRAokGLcPrqs/c3QFGcaMKN8tHcp3+GSj2wKgc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945756; c=relaxed/simple; bh=lm+IQu0UYKXj8LIs7koonBvkrQUealW2J/yiZC306Mc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DiLH1cOOXofc1xzbPWOGf09sFrMGHGtkmZl720RRiW2xaykwJ5/5SicbPCCmAVO7n8gpcYV70NAa9QzkyAbgyRl4L0w5ndH+XbvJ8I1V2aUS9Y2CvtSj18eOBBkK/gPRWVQ5w5eFlWAJpj321kie653dgIs2nFvBvpfKCb4WMVg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IXlYsV0s; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IXlYsV0s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A5B7C4AF0A; Sun, 14 Jul 2024 08:29:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945755; bh=lm+IQu0UYKXj8LIs7koonBvkrQUealW2J/yiZC306Mc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IXlYsV0soTpAS/FwG1H1OqUtVhbgFuomGKDzMym8Nwu/E4YSjJ6QT1MKQVhoB48jU NjSyvZzxuoGQC96+ec8vTWlSWSihOPdVhqQgw3MYcnzsiRfRRs99H8gfUXHhpzvEFc Z18+vWUhywojUDykp8yMsOeb3YV4s6t64TATaVimRPC+KcLgMm6tvTJUc4JGQXXVMh llL04Ks496IXu5OWCbiacCW5Wzaz83g7wbT9SwNppsX5VKflI8ufMMZR4ZA+ezEATd D0uDY4RraWWilRhawy7nwNdujfBQx/JIfZiT0bx2G2+WxAxh0S9yV4S4AR0v0XLRy/ x5Yltjh9DugpA== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 15/17] powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_DIRECT_CALLS Date: Sun, 14 Jul 2024 13:57:51 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add support for DYNAMIC_FTRACE_WITH_DIRECT_CALLS similar to the arm64 implementation. ftrace direct calls allow custom trampolines to be called into directly from function ftrace call sites, bypassing the ftrace trampoline completely. This functionality is currently utilized by BPF trampolines to hook into kernel function entries. Since we have limited relative branch range, we support ftrace direct calls through support for DYNAMIC_FTRACE_WITH_CALL_OPS. In this approach, ftrace trampoline is not entirely bypassed. Rather, it is re-purposed into a stub that reads direct_call field from the associated ftrace_ops structure and branches into that, if it is not NULL. For this, it is sufficient if we can ensure that the ftrace trampoline is reachable from all traceable functions. When multiple ftrace_ops are associated with a call site, we utilize a call back to set pt_regs->orig_gpr3 that can then be tested on the return path from the ftrace trampoline to branch into the direct caller. Signed-off-by: Naveen N Rao --- arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/ftrace.h | 15 +++ arch/powerpc/kernel/asm-offsets.c | 3 + arch/powerpc/kernel/trace/ftrace.c | 9 ++ arch/powerpc/kernel/trace/ftrace_entry.S | 114 +++++++++++++++++------ 5 files changed, 113 insertions(+), 29 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index cb6031d86dc9..29aab3770415 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -236,6 +236,7 @@ config PPC select HAVE_DYNAMIC_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_ARGS if ARCH_USING_PATCHABLE_FUNCTION_ENTRY || MPROFILE_KERNEL || PPC32 select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS if PPC_FTRACE_OUT_OF_LINE || (PPC32 && ARCH_USING_PATCHABLE_FUNCTION_ENTRY) + select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS if HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS select HAVE_DYNAMIC_FTRACE_WITH_REGS if ARCH_USING_PATCHABLE_FUNCTION_ENTRY || MPROFILE_KERNEL || PPC32 select HAVE_EBPF_JIT select HAVE_EFFICIENT_UNALIGNED_ACCESS diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 267bd52fef21..2f1a6d25838d 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -150,6 +150,21 @@ extern unsigned int ftrace_ool_stub_text_end_count, ftrace_ool_stub_text_count, #endif void ftrace_free_init_tramp(void); unsigned long ftrace_call_adjust(unsigned long addr); + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +/* + * When an ftrace registered caller is tracing a function that is also set by a + * register_ftrace_direct() call, it needs to be differentiated in the + * ftrace_caller trampoline so that the direct call can be invoked after the + * other ftrace ops. To do this, place the direct caller in the orig_gpr3 field + * of pt_regs. This tells ftrace_caller that there's a direct caller. + */ +static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr) +{ + struct pt_regs *regs = &fregs->regs; + regs->orig_gpr3 = addr; +} +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ #else static inline void ftrace_free_init_tramp(void) { } static inline unsigned long ftrace_call_adjust(unsigned long addr) { return addr; } diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 60d1e388c2ba..dbd56264a8bc 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -680,6 +680,9 @@ int main(void) #ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS OFFSET(FTRACE_OPS_FUNC, ftrace_ops, func); +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + OFFSET(FTRACE_OPS_DIRECT_CALL, ftrace_ops, direct_call); +#endif #endif return 0; diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 291c6c3d3a78..4316a7cfbdb8 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -150,6 +150,15 @@ static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_ else ip = rec->ip; + if (!is_offset_in_branch_range(addr - ip) && addr != FTRACE_ADDR && addr != FTRACE_REGS_ADDR) { + /* This can only happen with ftrace direct */ + if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS)) { + pr_err("0x%lx (0x%lx): Unexpected target address 0x%lx\n", ip, rec->ip, addr); + return -EINVAL; + } + addr = FTRACE_ADDR; + } + if (is_offset_in_branch_range(addr - ip)) /* Within range */ stub = addr; diff --git a/arch/powerpc/kernel/trace/ftrace_entry.S b/arch/powerpc/kernel/trace/ftrace_entry.S index c019380bdd6a..eea4cb3737a8 100644 --- a/arch/powerpc/kernel/trace/ftrace_entry.S +++ b/arch/powerpc/kernel/trace/ftrace_entry.S @@ -33,14 +33,38 @@ * and then arrange for the ftrace function to be called. */ .macro ftrace_regs_entry allregs - /* Save the original return address in A's stack frame */ - PPC_STL r0, LRSAVE(r1) /* Create a minimal stack frame for representing B */ PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) /* Create our stack frame + pt_regs */ PPC_STLU r1,-SWITCH_FRAME_SIZE(r1) + .if \allregs == 1 + SAVE_GPRS(11, 12, r1) + .endif + + /* Get the _mcount() call site out of LR */ + mflr r11 + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + /* Load the ftrace_op */ + PPC_LL r12, -(MCOUNT_INSN_SIZE*2 + SZL)(r11) + + /* Load direct_call from the ftrace_op */ + PPC_LL r12, FTRACE_OPS_DIRECT_CALL(r12) + PPC_LCMPI r12, 0 + .if \allregs == 1 + bne .Lftrace_direct_call_regs + .else + bne .Lftrace_direct_call + .endif +#endif + + /* Save the previous LR in pt_regs->link */ + PPC_STL r0, _LINK(r1) + /* Also save it in A's stack frame */ + PPC_STL r0, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE+LRSAVE(r1) + /* Save all gprs to pt_regs */ SAVE_GPR(0, r1) SAVE_GPRS(3, 10, r1) @@ -54,7 +78,7 @@ .if \allregs == 1 SAVE_GPR(2, r1) - SAVE_GPRS(11, 31, r1) + SAVE_GPRS(13, 31, r1) .else #if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE) SAVE_GPR(14, r1) @@ -67,20 +91,15 @@ .if \allregs == 1 /* Load special regs for save below */ + mfcr r7 mfmsr r8 mfctr r9 mfxer r10 - mfcr r11 .else /* Clear MSR to flag as ftrace_caller versus frace_regs_caller */ li r8, 0 .endif - /* Get the _mcount() call site out of LR */ - mflr r7 - /* Save the read LR in pt_regs->link */ - PPC_STL r0, _LINK(r1) - #ifdef CONFIG_PPC64 /* Save callee's TOC in the ABI compliant location */ std r2, STK_GOT(r1) @@ -88,8 +107,8 @@ #endif #ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS - /* r7 points to the instruction following the call to ftrace */ - PPC_LL r5, -(MCOUNT_INSN_SIZE*2 + SZL)(r7) + /* r11 points to the instruction following the call to ftrace */ + PPC_LL r5, -(MCOUNT_INSN_SIZE*2 + SZL)(r11) PPC_LL r12, FTRACE_OPS_FUNC(r5) mtctr r12 #else /* !CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS */ @@ -105,45 +124,51 @@ /* Save special regs */ PPC_STL r8, _MSR(r1) .if \allregs == 1 + PPC_STL r7, _CCR(r1) PPC_STL r9, _CTR(r1) PPC_STL r10, _XER(r1) - PPC_STL r11, _CCR(r1) .endif +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + /* Clear orig_gpr3 to later detect ftrace_direct call */ + li r7, 0 + PPC_STL r7, ORIG_GPR3(r1) +#endif + #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE /* Save our real return address in nvr for return */ .if \allregs == 0 SAVE_GPR(15, r1) .endif - mr r15, r7 + mr r15, r11 /* - * We want the ftrace location in the function, but our lr (in r7) + * We want the ftrace location in the function, but our lr (in r11) * points at the 'mtlr r0' instruction in the out of line stub. To * recover the ftrace location, we read the branch instruction in the * stub, and adjust our lr by the branch offset. * * See ftrace_init_ool_stub() for the profile sequence. */ - lwz r8, MCOUNT_INSN_SIZE(r7) + lwz r8, MCOUNT_INSN_SIZE(r11) slwi r8, r8, 6 srawi r8, r8, 6 - add r3, r7, r8 + add r3, r11, r8 /* * Override our nip to point past the branch in the original function. * This allows reliable stack trace and the ftrace stack tracer to work as-is. */ - add r7, r3, MCOUNT_INSN_SIZE + add r11, r3, MCOUNT_INSN_SIZE #else /* Calculate ip from nip-4 into r3 for call below */ - subi r3, r7, MCOUNT_INSN_SIZE + subi r3, r11, MCOUNT_INSN_SIZE #endif /* Save NIP as pt_regs->nip */ - PPC_STL r7, _NIP(r1) + PPC_STL r11, _NIP(r1) /* Also save it in B's stackframe header for proper unwind */ - PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) + PPC_STL r11, LRSAVE+SWITCH_FRAME_SIZE(r1) #if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE) - mr r14, r7 /* remember old NIP */ + mr r14, r11 /* remember old NIP */ #endif /* Put the original return address in r4 as parent_ip */ @@ -154,14 +179,32 @@ .endm .macro ftrace_regs_exit allregs +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + /* Check orig_gpr3 to detect ftrace_direct call */ + PPC_LL r3, ORIG_GPR3(r1) + PPC_LCMPI cr1, r3, 0 + mtctr r3 +#endif + + /* Restore possibly modified LR */ + PPC_LL r0, _LINK(r1) + #ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE /* Load ctr with the possibly modified NIP */ PPC_LL r3, _NIP(r1) - mtctr r3 - #ifdef CONFIG_LIVEPATCH_64 cmpd r14, r3 /* has NIP been altered? */ #endif + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + beq cr1,2f + mtlr r3 + b 3f +#endif +2: mtctr r3 + mtlr r0 +3: + #else /* !CONFIG_PPC_FTRACE_OUT_OF_LINE */ /* Load LR with the possibly modified NIP */ PPC_LL r3, _NIP(r1) @@ -185,12 +228,6 @@ #endif .endif - /* Restore possibly modified LR */ - PPC_LL r0, _LINK(r1) -#ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE - mtlr r0 -#endif - #ifdef CONFIG_PPC64 /* Restore callee's TOC */ ld r2, STK_GOT(r1) @@ -203,8 +240,12 @@ /* Based on the cmpd above, if the NIP was altered handle livepatch */ bne- livepatch_handler #endif + /* jump after _mcount site */ #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + bnectr cr1 +#endif /* * Return with blr to keep the link stack balanced. The function profiling sequence * uses 'mtlr r0' to restore LR. @@ -260,6 +301,21 @@ ftrace_no_trace: #endif #endif +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +.Lftrace_direct_call_regs: + mtctr r12 + REST_GPRS(11, 12, r1) + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE + bctr +.Lftrace_direct_call: + mtctr r12 + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE + bctr +SYM_FUNC_START(ftrace_stub_direct_tramp) + blr +SYM_FUNC_END(ftrace_stub_direct_tramp) +#endif + #ifdef CONFIG_LIVEPATCH_64 /* * This function runs in the mcount context, between two functions. As From patchwork Sun Jul 14 08:27:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732616 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5D09F76033; Sun, 14 Jul 2024 08:29:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945760; cv=none; b=gefy4jA/bEQd0YiKuNoR/j1/FgvyaxwrR3WrHxx1Yc8tD2OZXkHdnbXVUmrP0S7cNdMZt+0dFACMq58NQ7/VHupNOH3Ruee71hChygIYFJ+14R7+NeF+bpgYMgQlZKSyNDFIhtkV3EWlnkqPt/Pz5laSrZmCBCLU8QmpOxeshg8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945760; c=relaxed/simple; bh=u9jgla6YbJDeyFGkMjt0JK9jjbDJbcx+QV5+4gHm0hc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ugNrrG5BjtDbTY3jBz/6vdmXqkS1TfxHyXzSD/JpOIv+IXTfEzlkQzAPiZY22WhJ/ti/dXp0F9fG2Q82ALQlqgYer5PzH3GU4d7YS+890hTxZWtMJrZOaJEjW9c7NJ6g7y9LUDy1VNt1PMVTO3hxy/F/8397KgSh1Xctf/JzEc8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PcI1piYa; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PcI1piYa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76279C4AF09; Sun, 14 Jul 2024 08:29:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945760; bh=u9jgla6YbJDeyFGkMjt0JK9jjbDJbcx+QV5+4gHm0hc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PcI1piYakO5jIXRHsyUWUmAt0rINQfbMsa2lH8SuH3XdNYLhPpwg8KMtrL89RHVdA ZVjtQFqmXQECfrEBbbSwmi3YuvDNKQGVrpEdvj+JE6Y4coSo18Ac/exrhAMepSGOwW 1VmN3wPcSNpN0xLLGxL2zXPvC2VHjlDKJBds5L8AkUXkG/0abGZC/ZHWU7VHrb86lI w7RW4hlpGBj9Xy6D+IzJWsPW5U51KX4ec96PryNONYGulLkeXp+NmvArXlEMCy06nB bMPDCDoRmh7Xb+D9mypH7fUj9/ShZTtctVUYLqwv0/nmMy34COJv0ZAYdIHDvYI97U hA2kXSEvg/8zA== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 16/17] samples/ftrace: Add support for ftrace direct samples on powerpc Date: Sun, 14 Jul 2024 13:57:52 +0530 Message-ID: <1ecbd80f9d91dcf1f3a283a14fce7d3c3a0a0f71.1720942106.git.naveen@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add powerpc 32-bit and 64-bit samples for ftrace direct. This serves to show the sample instruction sequence to be used by ftrace direct calls to adhere to the ftrace ABI. On 64-bit powerpc, TOC setup requires some additional work. Signed-off-by: Naveen N Rao --- arch/powerpc/Kconfig | 2 + samples/ftrace/ftrace-direct-modify.c | 85 +++++++++++++++- samples/ftrace/ftrace-direct-multi-modify.c | 101 +++++++++++++++++++- samples/ftrace/ftrace-direct-multi.c | 79 ++++++++++++++- samples/ftrace/ftrace-direct-too.c | 83 +++++++++++++++- samples/ftrace/ftrace-direct.c | 69 ++++++++++++- 6 files changed, 414 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 29aab3770415..f6ff44acf112 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -275,6 +275,8 @@ config PPC select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RELIABLE_STACKTRACE select HAVE_RSEQ + select HAVE_SAMPLE_FTRACE_DIRECT if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS select HAVE_SETUP_PER_CPU_AREA if PPC64 select HAVE_SOFTIRQ_ON_OWN_STACK select HAVE_STACKPROTECTOR if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2) diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c index 81220390851a..cfea7a38befb 100644 --- a/samples/ftrace/ftrace-direct-modify.c +++ b/samples/ftrace/ftrace-direct-modify.c @@ -2,7 +2,7 @@ #include #include #include -#ifndef CONFIG_ARM64 +#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32) #include #endif @@ -199,6 +199,89 @@ asm ( #endif /* CONFIG_LOONGARCH */ +#ifdef CONFIG_PPC +#include + +#ifdef CONFIG_PPC64 +#define STACK_FRAME_SIZE 48 +#else +#define STACK_FRAME_SIZE 24 +#endif + +#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL) +#define PPC64_TOC_SAVE_AND_UPDATE \ +" std 2, 24(1)\n" \ +" bcl 20, 31, 1f\n" \ +" 1: mflr 12\n" \ +" ld 2, (99f - 1b)(12)\n" +#define PPC64_TOC_RESTORE \ +" ld 2, 24(1)\n" +#define PPC64_TOC \ +" 99: .quad .TOC.@tocbase\n" +#else +#define PPC64_TOC_SAVE_AND_UPDATE "" +#define PPC64_TOC_RESTORE "" +#define PPC64_TOC "" +#endif + +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtlr 0\n" +#define PPC_FTRACE_RET \ +" blr\n" +#else +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtctr 0\n" +#define PPC_FTRACE_RET \ +" mtlr 0\n" \ +" bctr\n" +#endif + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp1, @function\n" +" .globl my_tramp1\n" +" my_tramp1:\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mflr 0\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" + PPC64_TOC_SAVE_AND_UPDATE +" bl my_direct_func1\n" + PPC64_TOC_RESTORE +" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" + PPC_FTRACE_RESTORE_LR +" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_FTRACE_RET +" .size my_tramp1, .-my_tramp1\n" + +" .type my_tramp2, @function\n" +" .globl my_tramp2\n" +" my_tramp2:\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mflr 0\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" + PPC64_TOC_SAVE_AND_UPDATE +" bl my_direct_func2\n" + PPC64_TOC_RESTORE +" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" + PPC_FTRACE_RESTORE_LR +" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_FTRACE_RET + PPC64_TOC +" .size my_tramp2, .-my_tramp2\n" +" .popsection\n" +); + +#endif /* CONFIG_PPC */ + static struct ftrace_ops direct; static unsigned long my_tramp = (unsigned long)my_tramp1; diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c index f943e40d57fd..8f7986d698d8 100644 --- a/samples/ftrace/ftrace-direct-multi-modify.c +++ b/samples/ftrace/ftrace-direct-multi-modify.c @@ -2,7 +2,7 @@ #include #include #include -#ifndef CONFIG_ARM64 +#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32) #include #endif @@ -225,6 +225,105 @@ asm ( #endif /* CONFIG_LOONGARCH */ +#ifdef CONFIG_PPC +#include + +#ifdef CONFIG_PPC64 +#define STACK_FRAME_SIZE 48 +#else +#define STACK_FRAME_SIZE 24 +#endif + +#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL) +#define PPC64_TOC_SAVE_AND_UPDATE \ +" std 2, 24(1)\n" \ +" bcl 20, 31, 1f\n" \ +" 1: mflr 12\n" \ +" ld 2, (99f - 1b)(12)\n" +#define PPC64_TOC_RESTORE \ +" ld 2, 24(1)\n" +#define PPC64_TOC \ +" 99: .quad .TOC.@tocbase\n" +#else +#define PPC64_TOC_SAVE_AND_UPDATE "" +#define PPC64_TOC_RESTORE "" +#define PPC64_TOC "" +#endif + +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtlr 0\n" +#define PPC_FTRACE_RET \ +" blr\n" +#define PPC_FTRACE_RECOVER_IP \ +" lwz 8, 4(3)\n" \ +" li 9, 6\n" \ +" slw 8, 8, 9\n" \ +" sraw 8, 8, 9\n" \ +" add 3, 3, 8\n" \ +" addi 3, 3, 4\n" +#else +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtctr 0\n" +#define PPC_FTRACE_RET \ +" mtlr 0\n" \ +" bctr\n" +#define PPC_FTRACE_RECOVER_IP "" +#endif + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp1, @function\n" +" .globl my_tramp1\n" +" my_tramp1:\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mflr 0\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" + PPC64_TOC_SAVE_AND_UPDATE + PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mr 3, 0\n" + PPC_FTRACE_RECOVER_IP +" bl my_direct_func1\n" + PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" + PPC64_TOC_RESTORE +" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" + PPC_FTRACE_RESTORE_LR +" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_FTRACE_RET +" .size my_tramp1, .-my_tramp1\n" + +" .type my_tramp2, @function\n" +" .globl my_tramp2\n" +" my_tramp2:\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mflr 0\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" + PPC64_TOC_SAVE_AND_UPDATE + PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mr 3, 0\n" + PPC_FTRACE_RECOVER_IP +" bl my_direct_func2\n" + PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" + PPC64_TOC_RESTORE +" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" + PPC_FTRACE_RESTORE_LR +" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_FTRACE_RET + PPC64_TOC + " .size my_tramp2, .-my_tramp2\n" +" .popsection\n" +); + +#endif /* CONFIG_PPC */ + static unsigned long my_tramp = (unsigned long)my_tramp1; static unsigned long tramps[2] = { (unsigned long)my_tramp1, diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c index aed6df2927ce..db326c81a27d 100644 --- a/samples/ftrace/ftrace-direct-multi.c +++ b/samples/ftrace/ftrace-direct-multi.c @@ -4,7 +4,7 @@ #include /* for handle_mm_fault() */ #include #include -#ifndef CONFIG_ARM64 +#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32) #include #endif @@ -141,6 +141,83 @@ asm ( #endif /* CONFIG_LOONGARCH */ +#ifdef CONFIG_PPC +#include + +#ifdef CONFIG_PPC64 +#define STACK_FRAME_SIZE 48 +#else +#define STACK_FRAME_SIZE 24 +#endif + +#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL) +#define PPC64_TOC_SAVE_AND_UPDATE \ +" std 2, 24(1)\n" \ +" bcl 20, 31, 1f\n" \ +" 1: mflr 12\n" \ +" ld 2, (99f - 1b)(12)\n" +#define PPC64_TOC_RESTORE \ +" ld 2, 24(1)\n" +#define PPC64_TOC \ +" 99: .quad .TOC.@tocbase\n" +#else +#define PPC64_TOC_SAVE_AND_UPDATE "" +#define PPC64_TOC_RESTORE "" +#define PPC64_TOC "" +#endif + +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtlr 0\n" +#define PPC_FTRACE_RET \ +" blr\n" +#define PPC_FTRACE_RECOVER_IP \ +" lwz 8, 4(3)\n" \ +" li 9, 6\n" \ +" slw 8, 8, 9\n" \ +" sraw 8, 8, 9\n" \ +" add 3, 3, 8\n" \ +" addi 3, 3, 4\n" +#else +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtctr 0\n" +#define PPC_FTRACE_RET \ +" mtlr 0\n" \ +" bctr\n" +#define PPC_FTRACE_RECOVER_IP "" +#endif + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp, @function\n" +" .globl my_tramp\n" +" my_tramp:\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mflr 0\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" + PPC64_TOC_SAVE_AND_UPDATE + PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mr 3, 0\n" + PPC_FTRACE_RECOVER_IP +" bl my_direct_func\n" + PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" + PPC64_TOC_RESTORE +" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" + PPC_FTRACE_RESTORE_LR +" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_FTRACE_RET + PPC64_TOC +" .size my_tramp, .-my_tramp\n" +" .popsection\n" +); + +#endif /* CONFIG_PPC */ + static struct ftrace_ops direct; static int __init ftrace_direct_multi_init(void) diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c index 6ff546a5d7eb..3d0fa260332d 100644 --- a/samples/ftrace/ftrace-direct-too.c +++ b/samples/ftrace/ftrace-direct-too.c @@ -3,7 +3,7 @@ #include /* for handle_mm_fault() */ #include -#ifndef CONFIG_ARM64 +#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32) #include #endif @@ -153,6 +153,87 @@ asm ( #endif /* CONFIG_LOONGARCH */ +#ifdef CONFIG_PPC +#include + +#ifdef CONFIG_PPC64 +#define STACK_FRAME_SIZE 64 +#define STACK_FRAME_ARG1 32 +#define STACK_FRAME_ARG2 40 +#define STACK_FRAME_ARG3 48 +#define STACK_FRAME_ARG4 56 +#else +#define STACK_FRAME_SIZE 32 +#define STACK_FRAME_ARG1 16 +#define STACK_FRAME_ARG2 20 +#define STACK_FRAME_ARG3 24 +#define STACK_FRAME_ARG4 28 +#endif + +#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL) +#define PPC64_TOC_SAVE_AND_UPDATE \ +" std 2, 24(1)\n" \ +" bcl 20, 31, 1f\n" \ +" 1: mflr 12\n" \ +" ld 2, (99f - 1b)(12)\n" +#define PPC64_TOC_RESTORE \ +" ld 2, 24(1)\n" +#define PPC64_TOC \ +" 99: .quad .TOC.@tocbase\n" +#else +#define PPC64_TOC_SAVE_AND_UPDATE "" +#define PPC64_TOC_RESTORE "" +#define PPC64_TOC "" +#endif + +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtlr 0\n" +#define PPC_FTRACE_RET \ +" blr\n" +#else +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtctr 0\n" +#define PPC_FTRACE_RET \ +" mtlr 0\n" \ +" bctr\n" +#endif + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp, @function\n" +" .globl my_tramp\n" +" my_tramp:\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mflr 0\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" + PPC64_TOC_SAVE_AND_UPDATE + PPC_STL" 3, "__stringify(STACK_FRAME_ARG1)"(1)\n" + PPC_STL" 4, "__stringify(STACK_FRAME_ARG2)"(1)\n" + PPC_STL" 5, "__stringify(STACK_FRAME_ARG3)"(1)\n" + PPC_STL" 6, "__stringify(STACK_FRAME_ARG4)"(1)\n" +" bl my_direct_func\n" + PPC_LL" 6, "__stringify(STACK_FRAME_ARG4)"(1)\n" + PPC_LL" 5, "__stringify(STACK_FRAME_ARG3)"(1)\n" + PPC_LL" 4, "__stringify(STACK_FRAME_ARG2)"(1)\n" + PPC_LL" 3, "__stringify(STACK_FRAME_ARG1)"(1)\n" + PPC64_TOC_RESTORE +" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" + PPC_FTRACE_RESTORE_LR +" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_FTRACE_RET + PPC64_TOC +" .size my_tramp, .-my_tramp\n" +" .popsection\n" +); + +#endif /* CONFIG_PPC */ + static struct ftrace_ops direct; static int __init ftrace_direct_init(void) diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c index ef0945670e1e..956834b0d19a 100644 --- a/samples/ftrace/ftrace-direct.c +++ b/samples/ftrace/ftrace-direct.c @@ -3,7 +3,7 @@ #include /* for wake_up_process() */ #include -#ifndef CONFIG_ARM64 +#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32) #include #endif @@ -134,6 +134,73 @@ asm ( #endif /* CONFIG_LOONGARCH */ +#ifdef CONFIG_PPC +#include + +#ifdef CONFIG_PPC64 +#define STACK_FRAME_SIZE 48 +#else +#define STACK_FRAME_SIZE 24 +#endif + +#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL) +#define PPC64_TOC_SAVE_AND_UPDATE \ +" std 2, 24(1)\n" \ +" bcl 20, 31, 1f\n" \ +" 1: mflr 12\n" \ +" ld 2, (99f - 1b)(12)\n" +#define PPC64_TOC_RESTORE \ +" ld 2, 24(1)\n" +#define PPC64_TOC \ +" 99: .quad .TOC.@tocbase\n" +#else +#define PPC64_TOC_SAVE_AND_UPDATE "" +#define PPC64_TOC_RESTORE "" +#define PPC64_TOC "" +#endif + +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtlr 0\n" +#define PPC_FTRACE_RET \ +" blr\n" +#else +#define PPC_FTRACE_RESTORE_LR \ + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ +" mtctr 0\n" +#define PPC_FTRACE_RET \ +" mtlr 0\n" \ +" bctr\n" +#endif + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp, @function\n" +" .globl my_tramp\n" +" my_tramp:\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" mflr 0\n" + PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" + PPC64_TOC_SAVE_AND_UPDATE + PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" +" bl my_direct_func\n" + PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" + PPC64_TOC_RESTORE +" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" + PPC_FTRACE_RESTORE_LR +" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" + PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" + PPC_FTRACE_RET + PPC64_TOC +" .size my_tramp, .-my_tramp\n" +" .popsection\n" +); + +#endif /* CONFIG_PPC */ + static struct ftrace_ops direct; static int __init ftrace_direct_init(void) From patchwork Sun Jul 14 08:27:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732617 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5564E130AD7; Sun, 14 Jul 2024 08:29:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945765; cv=none; b=TO0d5vao4XWR0sqgX+m/mhej3pgJ0oIzoE8zJgzbVvcf5VXN27Fgi1D9PV9GwnP2CNJsx2z9QjxeYOeOYmnULAEGsE47WTyNGmvKoRtgFW+xBY1foT2W4ngVobiyBsxmjFr1UYj1C94NTHK5sV2dGIOxQsevZYPnYmRoAfkMmdg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945765; c=relaxed/simple; bh=ag4h4RKIQDz06qNnakpNHWL17BcW53wig3KlOSt0BX0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=o7dIGhk+cDAvTlqySbN55eDh9SNuimNr9EZFyfQ8ImHQ2An09UqLUfGyK/o412xkTCn2XgD86ikZJy5UIgRsVhP3jhHNA1qZsxoZ+ei04iPpYapZUjswYJDTgwEcMenN6ua9gbtxY8QcQKumtDPZpZlqst/KI8CK0zOUiA4aLZo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pjprLsBC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pjprLsBC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D857DC4AF09; Sun, 14 Jul 2024 08:29:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945764; bh=ag4h4RKIQDz06qNnakpNHWL17BcW53wig3KlOSt0BX0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pjprLsBCVBCan6HHonOUquyfItpECpYEuYMowY7ZHLSY51HuD2kwn7McERuvKXQKt yWuZ3RxMA3xr+PwfDX7DYcYYx+a/LTM/u2+A3JGpCi/uc+fw9/ry5AKp8nrPGvi4a2 F9wiTQuCdvaDqI0Q223CjldM4BpjVPXuBOGsBZRDaR7OZDXF8RyOW+Mq7vWRddBkJ6 xvjEPeFsfH0hJT6JiZFOHoq9gw95A0SN3wKJbDdD/8MA3xlBiunyxjfEpQTTFazybA lW+loYUnkuyU7xlMrV0ZuVPRSsesrpDLJtCPdyPIdEVqlHF6WYxnrIBBvg1U6KA9wV 6k4W0g3Qfn6+A== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 17/17] powerpc64/bpf: Add support for bpf trampolines Date: Sun, 14 Jul 2024 13:57:53 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add support for bpf_arch_text_poke() and arch_prepare_bpf_trampoline() for 64-bit powerpc. While the code is generic, BPF trampolines are only enabled on 64-bit powerpc. 32-bit powerpc will need testing and some updates. BPF Trampolines adhere to the existing ftrace ABI utilizing a two-instruction profiling sequence, as well as the newer ABI utilizing a three-instruction profiling sequence enabling return with a 'blr'. The trampoline code itself closely follows x86 implementation. BPF prog JIT is extended to mimic 64-bit powerpc approach for ftrace having a single nop at function entry, followed by the function profiling sequence out-of-line and a separate long branch stub for calls to trampolines that are out of range. A dummy_tramp is provided to simplify synchronization similar to arm64. When attaching a bpf trampoline to a bpf prog, we can patch up to three things: - the nop at bpf prog entry to go to the out-of-line stub - the instruction in the out-of-line stub to either call the bpf trampoline directly, or to branch to the long_branch stub. - the trampoline address before the long_branch stub. We do not need any synchronization here since we always have a valid branch target regardless of the order in which the above stores are seen. dummy_tramp ensures that the long_branch stub goes to a valid destination on other cpus, even when the branch to the long_branch stub is seen before the updated trampoline address. However, when detaching a bpf trampoline from a bpf prog, or if changing the bpf trampoline address, we need synchronization to ensure that other cpus can no longer branch into the older trampoline so that it can be safely freed. bpf_tramp_image_put() uses rcu_tasks to ensure all cpus make forward progress, but we still need to ensure that other cpus execute isync (or some CSI) so that they don't go back into the trampoline again. Signed-off-by: Naveen N Rao --- arch/powerpc/include/asm/ppc-opcode.h | 14 + arch/powerpc/net/bpf_jit.h | 12 + arch/powerpc/net/bpf_jit_comp.c | 842 +++++++++++++++++++++++++- arch/powerpc/net/bpf_jit_comp32.c | 7 +- arch/powerpc/net/bpf_jit_comp64.c | 7 +- 5 files changed, 879 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h index b98a9e982c03..4312bcb913a4 100644 --- a/arch/powerpc/include/asm/ppc-opcode.h +++ b/arch/powerpc/include/asm/ppc-opcode.h @@ -587,12 +587,26 @@ #define PPC_RAW_MTSPR(spr, d) (0x7c0003a6 | ___PPC_RS(d) | __PPC_SPR(spr)) #define PPC_RAW_EIEIO() (0x7c0006ac) +/* bcl 20,31,$+4 */ +#define PPC_RAW_BCL4() (0x429f0005) #define PPC_RAW_BRANCH(offset) (0x48000000 | PPC_LI(offset)) #define PPC_RAW_BL(offset) (0x48000001 | PPC_LI(offset)) #define PPC_RAW_TW(t0, a, b) (0x7c000008 | ___PPC_RS(t0) | ___PPC_RA(a) | ___PPC_RB(b)) #define PPC_RAW_TRAP() PPC_RAW_TW(31, 0, 0) #define PPC_RAW_SETB(t, bfa) (0x7c000100 | ___PPC_RT(t) | ___PPC_RA((bfa) << 2)) +#ifdef CONFIG_PPC32 +#define PPC_RAW_STL PPC_RAW_STW +#define PPC_RAW_STLU PPC_RAW_STWU +#define PPC_RAW_LL PPC_RAW_LWZ +#define PPC_RAW_CMPLI PPC_RAW_CMPWI +#else +#define PPC_RAW_STL PPC_RAW_STD +#define PPC_RAW_STLU PPC_RAW_STDU +#define PPC_RAW_LL PPC_RAW_LD +#define PPC_RAW_CMPLI PPC_RAW_CMPDI +#endif + /* Deal with instructions that older assemblers aren't aware of */ #define PPC_BCCTR_FLUSH stringify_in_c(.long PPC_INST_BCCTR_FLUSH) #define PPC_CP_ABORT stringify_in_c(.long PPC_RAW_CP_ABORT) diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h index cdea5dccaefe..2d04ce5a23da 100644 --- a/arch/powerpc/net/bpf_jit.h +++ b/arch/powerpc/net/bpf_jit.h @@ -12,6 +12,7 @@ #include #include +#include #ifdef CONFIG_PPC64_ELF_ABI_V1 #define FUNCTION_DESCR_SIZE 24 @@ -21,6 +22,9 @@ #define CTX_NIA(ctx) ((unsigned long)ctx->idx * 4) +#define SZL sizeof(unsigned long) +#define BPF_INSN_SAFETY 64 + #define PLANT_INSTR(d, idx, instr) \ do { if (d) { (d)[idx] = instr; } idx++; } while (0) #define EMIT(instr) PLANT_INSTR(image, ctx->idx, instr) @@ -81,6 +85,13 @@ EMIT(PPC_RAW_ORI(d, d, (uintptr_t)(i) & \ 0xffff)); \ } } while (0) +#define PPC_LI_ADDR PPC_LI64 +#define PPC64_LOAD_PACA() \ + EMIT(PPC_RAW_LD(_R2, _R13, offsetof(struct paca_struct, kernel_toc))) +#else +#define PPC_LI64(d, i) BUILD_BUG() +#define PPC_LI_ADDR PPC_LI32 +#define PPC64_LOAD_PACA() BUILD_BUG() #endif /* @@ -165,6 +176,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct code u32 *addrs, int pass, bool extra_pass); void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx); void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx); +void bpf_jit_build_fentry_stubs(u32 *image, struct codegen_context *ctx); void bpf_jit_realloc_regs(struct codegen_context *ctx); int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr); diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 984655419da5..bed1d26e7069 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -22,11 +22,81 @@ #include "bpf_jit.h" +/* These offsets are from bpf prog end and stay the same across progs */ +static int bpf_jit_ool_stub, bpf_jit_long_branch_stub; + static void bpf_jit_fill_ill_insns(void *area, unsigned int size) { memset32(area, BREAKPOINT_INSTRUCTION, size / 4); } +void dummy_tramp(void); + +asm ( +" .pushsection .text, \"ax\", @progbits ;" +" .global dummy_tramp ;" +" .type dummy_tramp, @function ;" +"dummy_tramp: ;" +#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE +" blr ;" +#else +/* LR is always in r11, so we don't need a 'mflr r11' here */ +" mtctr 11 ;" +" mtlr 0 ;" +" bctr ;" +#endif +" .size dummy_tramp, .-dummy_tramp ;" +" .popsection ;" +); + +void bpf_jit_build_fentry_stubs(u32 *image, struct codegen_context *ctx) +{ + int ool_stub_idx, long_branch_stub_idx; + + /* + * Out-of-line stub: + * mflr r0 + * [b|bl] tramp + * mtlr r0 // only with CONFIG_PPC_FTRACE_OUT_OF_LINE + * b bpf_func + 4 + */ + ool_stub_idx = ctx->idx; + EMIT(PPC_RAW_MFLR(_R0)); + EMIT(PPC_RAW_NOP()); + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + EMIT(PPC_RAW_MTLR(_R0)); + WARN_ON_ONCE(!is_offset_in_branch_range(4 - (long)ctx->idx * 4)); + EMIT(PPC_RAW_BRANCH(4 - (long)ctx->idx * 4)); + + /* + * Long branch stub: + * .long + * mflr r11 + * bcl 20,31,$+4 + * mflr r12 + * ld r12, -8-SZL(r12) + * mtctr r12 + * mtlr r11 // needed to retain ftrace ABI + * bctr + */ + if (image) + *((unsigned long *)&image[ctx->idx]) = (unsigned long)dummy_tramp; + ctx->idx += SZL / 4; + long_branch_stub_idx = ctx->idx; + EMIT(PPC_RAW_MFLR(_R11)); + EMIT(PPC_RAW_BCL4()); + EMIT(PPC_RAW_MFLR(_R12)); + EMIT(PPC_RAW_LL(_R12, _R12, -8-SZL)); + EMIT(PPC_RAW_MTCTR(_R12)); + EMIT(PPC_RAW_MTLR(_R11)); + EMIT(PPC_RAW_BCTR()); + + if (!bpf_jit_ool_stub) { + bpf_jit_ool_stub = (ctx->idx - ool_stub_idx) * 4; + bpf_jit_long_branch_stub = (ctx->idx - long_branch_stub_idx) * 4; + } +} + int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr) { if (!exit_addr || is_offset_in_branch_range(exit_addr - (ctx->idx * 4))) { @@ -222,7 +292,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) fp->bpf_func = (void *)fimage; fp->jited = 1; - fp->jited_len = proglen + FUNCTION_DESCR_SIZE; + fp->jited_len = cgctx.idx * 4 + FUNCTION_DESCR_SIZE; if (!fp->is_func || extra_pass) { if (bpf_jit_binary_pack_finalize(fp, fhdr, hdr)) { @@ -369,3 +439,773 @@ bool bpf_jit_supports_far_kfunc_call(void) { return IS_ENABLED(CONFIG_PPC64); } + +void *arch_alloc_bpf_trampoline(unsigned int size) +{ + return bpf_prog_pack_alloc(size, bpf_jit_fill_ill_insns); +} + +void arch_free_bpf_trampoline(void *image, unsigned int size) +{ + bpf_prog_pack_free(image, size); +} + +int arch_protect_bpf_trampoline(void *image, unsigned int size) +{ + return 0; +} + +static int invoke_bpf_prog(u32 *image, u32 *ro_image, struct codegen_context *ctx, + struct bpf_tramp_link *l, int regs_off, int retval_off, + int run_ctx_off, bool save_ret) +{ + struct bpf_prog *p = l->link.prog; + ppc_inst_t branch_insn; + u32 jmp_idx; + int ret = 0; + + /* Save cookie */ + if (IS_ENABLED(CONFIG_PPC64)) { + PPC_LI64(_R3, l->cookie); + EMIT(PPC_RAW_STD(_R3, _R1, run_ctx_off + offsetof(struct bpf_tramp_run_ctx, + bpf_cookie))); + } else { + PPC_LI32(_R3, l->cookie >> 32); + PPC_LI32(_R4, l->cookie); + EMIT(PPC_RAW_STW(_R3, _R1, + run_ctx_off + offsetof(struct bpf_tramp_run_ctx, bpf_cookie))); + EMIT(PPC_RAW_STW(_R4, _R1, + run_ctx_off + offsetof(struct bpf_tramp_run_ctx, bpf_cookie) + 4)); + } + + /* __bpf_prog_enter(p, &bpf_tramp_run_ctx) */ + PPC_LI_ADDR(_R3, p); + EMIT(PPC_RAW_MR(_R25, _R3)); + EMIT(PPC_RAW_ADDI(_R4, _R1, run_ctx_off)); + ret = bpf_jit_emit_func_call_rel(image, ro_image, ctx, (unsigned long)bpf_trampoline_enter(p)); + if (ret) + return ret; + + /* Remember prog start time returned by __bpf_prog_enter */ + EMIT(PPC_RAW_MR(_R26, _R3)); + + /* + * if (__bpf_prog_enter(p) == 0) + * goto skip_exec_of_prog; + * + * Emit a nop to be later patched with conditional branch, once offset is known + */ + EMIT(PPC_RAW_CMPLI(_R3, 0)); + jmp_idx = ctx->idx; + EMIT(PPC_RAW_NOP()); + + /* p->bpf_func(ctx) */ + EMIT(PPC_RAW_ADDI(_R3, _R1, regs_off)); + if (!p->jited) + PPC_LI_ADDR(_R4, (unsigned long)p->insnsi); + if (!create_branch(&branch_insn, (u32 *)&ro_image[ctx->idx], (unsigned long)p->bpf_func, + BRANCH_SET_LINK)) { + if (image) + image[ctx->idx] = ppc_inst_val(branch_insn); + ctx->idx++; + } else { + EMIT(PPC_RAW_LL(_R12, _R25, offsetof(struct bpf_prog, bpf_func))); + EMIT(PPC_RAW_MTCTR(_R12)); + EMIT(PPC_RAW_BCTRL()); + } + + if (save_ret) + EMIT(PPC_RAW_STL(_R3, _R1, retval_off)); + + /* Fix up branch */ + if (image) { + if (create_cond_branch(&branch_insn, &image[jmp_idx], + (unsigned long)&image[ctx->idx], COND_EQ << 16)) + return -EINVAL; + image[jmp_idx] = ppc_inst_val(branch_insn); + } + + /* __bpf_prog_exit(p, start_time, &bpf_tramp_run_ctx) */ + EMIT(PPC_RAW_MR(_R3, _R25)); + EMIT(PPC_RAW_MR(_R4, _R26)); + EMIT(PPC_RAW_ADDI(_R5, _R1, run_ctx_off)); + ret = bpf_jit_emit_func_call_rel(image, ro_image, ctx, (unsigned long)bpf_trampoline_exit(p)); + + return ret; +} + +static int invoke_bpf_mod_ret(u32 *image, u32 *ro_image, struct codegen_context *ctx, + struct bpf_tramp_links *tl, int regs_off, int retval_off, + int run_ctx_off, u32 *branches) +{ + int i; + + /* + * The first fmod_ret program will receive a garbage return value. + * Set this to 0 to avoid confusing the program. + */ + EMIT(PPC_RAW_LI(_R3, 0)); + EMIT(PPC_RAW_STL(_R3, _R1, retval_off)); + for (i = 0; i < tl->nr_links; i++) { + if (invoke_bpf_prog(image, ro_image, ctx, tl->links[i], regs_off, retval_off, + run_ctx_off, true)) + return -EINVAL; + + /* + * mod_ret prog stored return value after prog ctx. Emit: + * if (*(u64 *)(ret_val) != 0) + * goto do_fexit; + */ + EMIT(PPC_RAW_LL(_R3, _R1, retval_off)); + EMIT(PPC_RAW_CMPLI(_R3, 0)); + + /* + * Save the location of the branch and generate a nop, which is + * replaced with a conditional jump once do_fexit (i.e. the + * start of the fexit invocation) is finalized. + */ + branches[i] = ctx->idx; + EMIT(PPC_RAW_NOP()); + } + + return 0; +} + +static void bpf_trampoline_setup_tail_call_cnt(u32 *image, struct codegen_context *ctx, + int func_frame_offset, int r4_off) +{ + if (IS_ENABLED(CONFIG_PPC64)) { + /* See bpf_jit_stack_tailcallcnt() */ + int tailcallcnt_offset = 6 * 8; + + EMIT(PPC_RAW_LL(_R3, _R1, func_frame_offset - tailcallcnt_offset)); + EMIT(PPC_RAW_STL(_R3, _R1, -tailcallcnt_offset)); + } else { + /* See bpf_jit_stack_offsetof() and BPF_PPC_TC */ + EMIT(PPC_RAW_LL(_R4, _R1, r4_off)); + } +} + +static void bpf_trampoline_restore_tail_call_cnt(u32 *image, struct codegen_context *ctx, + int func_frame_offset, int r4_off) +{ + if (IS_ENABLED(CONFIG_PPC64)) { + /* See bpf_jit_stack_tailcallcnt() */ + int tailcallcnt_offset = 6 * 8; + + EMIT(PPC_RAW_LL(_R3, _R1, -tailcallcnt_offset)); + EMIT(PPC_RAW_STL(_R3, _R1, func_frame_offset - tailcallcnt_offset)); + } else { + /* See bpf_jit_stack_offsetof() and BPF_PPC_TC */ + EMIT(PPC_RAW_STL(_R4, _R1, r4_off)); + } +} + +static void bpf_trampoline_save_args(u32 *image, struct codegen_context *ctx, int func_frame_offset, + int nr_regs, int regs_off) +{ + int param_save_area_offset; + + param_save_area_offset = func_frame_offset; /* the two frames we alloted */ + param_save_area_offset += STACK_FRAME_MIN_SIZE; /* param save area is past the frame header */ + + for (int i = 0; i < nr_regs; i++) { + if (i < 8) { + EMIT(PPC_RAW_STL(_R3 + i, _R1, regs_off + i * SZL)); + } else { + EMIT(PPC_RAW_LL(_R3, _R1, param_save_area_offset + i * SZL)); + EMIT(PPC_RAW_STL(_R3, _R1, regs_off + i * SZL)); + } + } +} + +/* Used when restoring just the register parameters when returning back */ +static void bpf_trampoline_restore_args_regs(u32 *image, struct codegen_context *ctx, + int nr_regs, int regs_off) +{ + for (int i = 0; i < nr_regs && i < 8; i++) + EMIT(PPC_RAW_LL(_R3 + i, _R1, regs_off + i * SZL)); +} + +/* Used when we call into the traced function. Replicate parameter save area */ +static void bpf_trampoline_restore_args_stack(u32 *image, struct codegen_context *ctx, + int func_frame_offset, int nr_regs, int regs_off) +{ + int param_save_area_offset; + + param_save_area_offset = func_frame_offset; /* the two frames we alloted */ + param_save_area_offset += STACK_FRAME_MIN_SIZE; /* param save area is past the frame header */ + + for (int i = 8; i < nr_regs; i++) { + EMIT(PPC_RAW_LL(_R3, _R1, param_save_area_offset + i * SZL)); + EMIT(PPC_RAW_STL(_R3, _R1, STACK_FRAME_MIN_SIZE + i * SZL)); + } + bpf_trampoline_restore_args_regs(image, ctx, nr_regs, regs_off); +} + +static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_image, + void *rw_image_end, void *ro_image, + const struct btf_func_model *m, u32 flags, + struct bpf_tramp_links *tlinks, + void *func_addr) +{ + int regs_off, nregs_off, ip_off, run_ctx_off, retval_off, nvr_off, alt_lr_off, r4_off; + int i, ret, nr_regs, bpf_frame_size = 0, bpf_dummy_frame_size = 0, func_frame_offset; + struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN]; + struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY]; + struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT]; + struct codegen_context codegen_ctx, *ctx; + u32 *image = (u32 *)rw_image; + ppc_inst_t branch_insn; + u32 *branches = NULL; + bool save_ret; + + if (IS_ENABLED(CONFIG_PPC32)) + return -ENOTSUPP; + + nr_regs = m->nr_args; + /* Extra registers for struct arguments */ + for (i = 0; i < m->nr_args; i++) + if (m->arg_size[i] > SZL) + nr_regs += round_up(m->arg_size[i], SZL) / SZL - 1; + + if (nr_regs > MAX_BPF_FUNC_ARGS) + return -ENOTSUPP; + + ctx = &codegen_ctx; + memset(ctx, 0, sizeof(*ctx)); + + /* + * Generated stack layout: + * + * func prev back chain [ back chain ] + * [ ] + * bpf prog redzone/tailcallcnt [ ... ] 64 bytes (64-bit powerpc) + * [ ] -- + * LR save area [ r0 save (64-bit) ] | header + * [ r0 save (32-bit) ] | + * dummy frame for unwind [ back chain 1 ] -- + * [ padding ] align stack frame + * r4_off [ r4 (tailcallcnt) ] optional - 32-bit powerpc + * alt_lr_off [ real lr (ool stub)] optional - actual lr + * [ r26 ] + * nvr_off [ r25 ] nvr save area + * retval_off [ return value ] + * [ reg argN ] + * [ ... ] + * regs_off [ reg_arg1 ] prog ctx context + * nregs_off [ args count ] + * ip_off [ traced function ] + * [ ... ] + * run_ctx_off [ bpf_tramp_run_ctx ] + * [ reg argN ] + * [ ... ] + * param_save_area [ reg_arg1 ] min 8 doublewords, per ABI + * [ TOC save (64-bit) ] -- + * [ LR save (64-bit) ] | header + * [ LR save (32-bit) ] | + * bpf trampoline frame [ back chain 2 ] -- + * + */ + + /* Minimum stack frame header */ + bpf_frame_size = STACK_FRAME_MIN_SIZE; + + /* + * Room for parameter save area. + * + * Per the ABI, this is required if we call into the traced function (BPF_TRAMP_F_CALL_ORIG): + * - if the function takes more than 8 arguments for the rest to spill onto the stack + * - or, if the function has variadic arguments + * - or, if this functions's prototype was not available to the caller + * + * Reserve space for at least 8 registers for now. This can be optimized later. + */ + bpf_frame_size += (nr_regs > 8 ? nr_regs : 8) * SZL; + + /* Room for struct bpf_tramp_run_ctx */ + run_ctx_off = bpf_frame_size; + bpf_frame_size += round_up(sizeof(struct bpf_tramp_run_ctx), SZL); + + /* Room for IP address argument */ + ip_off = bpf_frame_size; + if (flags & BPF_TRAMP_F_IP_ARG) + bpf_frame_size += SZL; + + /* Room for args count */ + nregs_off = bpf_frame_size; + bpf_frame_size += SZL; + + /* Room for args */ + regs_off = bpf_frame_size; + bpf_frame_size += nr_regs * SZL; + + /* Room for return value of func_addr or fentry prog */ + retval_off = bpf_frame_size; + save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET); + if (save_ret) + bpf_frame_size += SZL; + + /* Room for nvr save area */ + nvr_off = bpf_frame_size; + bpf_frame_size += 2 * SZL; + + /* Optional save area for actual LR in case of ool ftrace */ + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) { + alt_lr_off = bpf_frame_size; + bpf_frame_size += SZL; + } + + if (IS_ENABLED(CONFIG_PPC32)) { + if (nr_regs < 2) { + r4_off = bpf_frame_size; + bpf_frame_size += SZL; + } else { + r4_off = regs_off + SZL; + } + } + + /* Padding to align stack frame, if any */ + bpf_frame_size = round_up(bpf_frame_size, SZL * 2); + + /* Dummy frame size for proper unwind - includes 64-bytes red zone for 64-bit powerpc */ + bpf_dummy_frame_size = STACK_FRAME_MIN_SIZE + 64; + + /* Offset to the traced function's stack frame */ + func_frame_offset = bpf_dummy_frame_size + bpf_frame_size; + + /* Create dummy frame for unwind, store original return value */ + EMIT(PPC_RAW_STL(_R0, _R1, PPC_LR_STKOFF)); + /* Protect red zone where tail call count goes */ + EMIT(PPC_RAW_STLU(_R1, _R1, -bpf_dummy_frame_size)); + + /* Create our stack frame */ + EMIT(PPC_RAW_STLU(_R1, _R1, -bpf_frame_size)); + + /* 64-bit: Save TOC and load kernel TOC */ + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { + EMIT(PPC_RAW_STD(_R2, _R1, 24)); + PPC64_LOAD_PACA(); + } + + /* 32-bit: save tail call count in r4 */ + if (IS_ENABLED(CONFIG_PPC32) && nr_regs < 2) + EMIT(PPC_RAW_STL(_R4, _R1, r4_off)); + + bpf_trampoline_save_args(image, ctx, func_frame_offset, nr_regs, regs_off); + + /* Save our return address */ + EMIT(PPC_RAW_MFLR(_R3)); + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + EMIT(PPC_RAW_STL(_R3, _R1, alt_lr_off)); + else + EMIT(PPC_RAW_STL(_R3, _R1, bpf_frame_size + PPC_LR_STKOFF)); + + /* + * Save ip address of the traced function. + * We could recover this from LR, but we will need to address for OOL trampoline, + * and optional GEP area. + */ + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) || flags & BPF_TRAMP_F_IP_ARG) { + EMIT(PPC_RAW_LWZ(_R4, _R3, 4)); + EMIT(PPC_RAW_SLWI(_R4, _R4, 6)); + EMIT(PPC_RAW_SRAWI(_R4, _R4, 6)); + EMIT(PPC_RAW_ADD(_R3, _R3, _R4)); + EMIT(PPC_RAW_ADDI(_R3, _R3, 4)); + } + + if (flags & BPF_TRAMP_F_IP_ARG) + EMIT(PPC_RAW_STL(_R3, _R1, ip_off)); + + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + /* Fake our LR for unwind */ + EMIT(PPC_RAW_STL(_R3, _R1, bpf_frame_size + PPC_LR_STKOFF)); + + /* Save function arg count -- see bpf_get_func_arg_cnt() */ + EMIT(PPC_RAW_LI(_R3, nr_regs)); + EMIT(PPC_RAW_STL(_R3, _R1, nregs_off)); + + /* Save nv regs */ + EMIT(PPC_RAW_STL(_R25, _R1, nvr_off)); + EMIT(PPC_RAW_STL(_R26, _R1, nvr_off + SZL)); + + if (flags & BPF_TRAMP_F_CALL_ORIG) { + PPC_LI_ADDR(_R3, (unsigned long)im); + ret = bpf_jit_emit_func_call_rel(image, ro_image, ctx, (unsigned long)__bpf_tramp_enter); + if (ret) + return ret; + } + + for (i = 0; i < fentry->nr_links; i++) + if (invoke_bpf_prog(image, ro_image, ctx, fentry->links[i], regs_off, retval_off, + run_ctx_off, flags & BPF_TRAMP_F_RET_FENTRY_RET)) + return -EINVAL; + + if (fmod_ret->nr_links) { + branches = kcalloc(fmod_ret->nr_links, sizeof(u32), GFP_KERNEL); + if (!branches) + return -ENOMEM; + + if (invoke_bpf_mod_ret(image, ro_image, ctx, fmod_ret, regs_off, retval_off, + run_ctx_off, branches)) { + ret = -EINVAL; + goto cleanup; + } + } + + /* Call the traced function */ + if (flags & BPF_TRAMP_F_CALL_ORIG) { + /* + * The address in LR save area points to the correct point in the original function + * with both PPC_FTRACE_OUT_OF_LINE as well as with traditional ftrace instruction + * sequence + */ + EMIT(PPC_RAW_LL(_R3, _R1, bpf_frame_size + PPC_LR_STKOFF)); + EMIT(PPC_RAW_MTCTR(_R3)); + + /* Replicate tail_call_cnt before calling the original BPF prog */ + if (flags & BPF_TRAMP_F_TAIL_CALL_CTX) + bpf_trampoline_setup_tail_call_cnt(image, ctx, func_frame_offset, r4_off); + + /* Restore args */ + bpf_trampoline_restore_args_stack(image, ctx, func_frame_offset, nr_regs, regs_off); + + /* Restore TOC for 64-bit */ + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + EMIT(PPC_RAW_LD(_R2, _R1, 24)); + EMIT(PPC_RAW_BCTRL()); + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + PPC64_LOAD_PACA(); + + /* Store return value for bpf prog to access */ + EMIT(PPC_RAW_STL(_R3, _R1, retval_off)); + + /* Restore updated tail_call_cnt */ + if (flags & BPF_TRAMP_F_TAIL_CALL_CTX) + bpf_trampoline_restore_tail_call_cnt(image, ctx, func_frame_offset, r4_off); + + /* Reserve space to patch branch instruction to skip fexit progs */ + im->ip_after_call = &((u32 *)ro_image)[ctx->idx]; + EMIT(PPC_RAW_NOP()); + } + + /* Update branches saved in invoke_bpf_mod_ret with address of do_fexit */ + for (i = 0; i < fmod_ret->nr_links && image; i++) { + if (create_cond_branch(&branch_insn, &image[branches[i]], + (unsigned long)&image[ctx->idx], COND_NE << 16)) { + ret = -EINVAL; + goto cleanup; + } + + image[branches[i]] = ppc_inst_val(branch_insn); + } + + for (i = 0; i < fexit->nr_links; i++) + if (invoke_bpf_prog(image, ro_image, ctx, fexit->links[i], regs_off, retval_off, + run_ctx_off, false)) { + ret = -EINVAL; + goto cleanup; + } + + if (flags & BPF_TRAMP_F_CALL_ORIG) { + im->ip_epilogue = &((u32 *)ro_image)[ctx->idx]; + PPC_LI_ADDR(_R3, im); + ret = bpf_jit_emit_func_call_rel(image, ro_image, ctx, (unsigned long)__bpf_tramp_exit); + if (ret) + goto cleanup; + } + + if (flags & BPF_TRAMP_F_RESTORE_REGS) + bpf_trampoline_restore_args_regs(image, ctx, nr_regs, regs_off); + + /* Restore return value of func_addr or fentry prog */ + if (save_ret) + EMIT(PPC_RAW_LL(_R3, _R1, retval_off)); + + /* Restore nv regs */ + EMIT(PPC_RAW_LL(_R26, _R1, nvr_off + SZL)); + EMIT(PPC_RAW_LL(_R25, _R1, nvr_off)); + + /* Epilogue */ + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + EMIT(PPC_RAW_LD(_R2, _R1, 24)); + if (flags & BPF_TRAMP_F_SKIP_FRAME) { + /* Skip the traced function and return to parent */ + EMIT(PPC_RAW_ADDI(_R1, _R1, func_frame_offset)); + EMIT(PPC_RAW_LL(_R0, _R1, PPC_LR_STKOFF)); + EMIT(PPC_RAW_MTLR(_R0)); + EMIT(PPC_RAW_BLR()); + } else { + if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) { + EMIT(PPC_RAW_LL(_R0, _R1, alt_lr_off)); + EMIT(PPC_RAW_MTLR(_R0)); + EMIT(PPC_RAW_ADDI(_R1, _R1, func_frame_offset)); + EMIT(PPC_RAW_LL(_R0, _R1, PPC_LR_STKOFF)); + EMIT(PPC_RAW_BLR()); + } else { + EMIT(PPC_RAW_LL(_R0, _R1, bpf_frame_size + PPC_LR_STKOFF)); + EMIT(PPC_RAW_MTCTR(_R0)); + EMIT(PPC_RAW_ADDI(_R1, _R1, func_frame_offset)); + EMIT(PPC_RAW_LL(_R0, _R1, PPC_LR_STKOFF)); + EMIT(PPC_RAW_MTLR(_R0)); + EMIT(PPC_RAW_BCTR()); + } + } + + /* Make sure the trampoline generation logic doesn't overflow */ + if (image && WARN_ON_ONCE(&image[ctx->idx] > (u32 *)rw_image_end - BPF_INSN_SAFETY)) { + ret = -EFAULT; + goto cleanup; + } + ret = ctx->idx * 4 + BPF_INSN_SAFETY * 4; + +cleanup: + kfree(branches); + return ret; +} + +int arch_bpf_trampoline_size(const struct btf_func_model *m, u32 flags, + struct bpf_tramp_links *tlinks, void *func_addr) +{ + struct bpf_tramp_image im; + void *image; + int ret; + + /* + * Allocate a temporary buffer for __arch_prepare_bpf_trampoline(). + * This will NOT cause fragmentation in direct map, as we do not + * call set_memory_*() on this buffer. + * + * We cannot use kvmalloc here, because we need image to be in + * module memory range. + */ + image = bpf_jit_alloc_exec(PAGE_SIZE); + if (!image) + return -ENOMEM; + + ret = __arch_prepare_bpf_trampoline(&im, image, image + PAGE_SIZE, image, + m, flags, tlinks, func_addr); + bpf_jit_free_exec(image); + + return ret; +} + +int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end, + const struct btf_func_model *m, u32 flags, + struct bpf_tramp_links *tlinks, + void *func_addr) +{ + u32 size = image_end - image; + void *rw_image, *tmp; + int ret; + + /* + * rw_image doesn't need to be in module memory range, so we can + * use kvmalloc. + */ + rw_image = kvmalloc(size, GFP_KERNEL); + if (!rw_image) + return -ENOMEM; + + ret = __arch_prepare_bpf_trampoline(im, rw_image, rw_image + size, image, m, + flags, tlinks, func_addr); + if (ret < 0) + goto out; + + if (bpf_jit_enable > 1) + bpf_jit_dump(1, ret - BPF_INSN_SAFETY * 4, 1, rw_image); + + tmp = bpf_arch_text_copy(image, rw_image, size); + if (IS_ERR(tmp)) + ret = PTR_ERR(tmp); + +out: + kvfree(rw_image); + return ret; +} + +static int bpf_modify_inst(void *ip, ppc_inst_t old_inst, ppc_inst_t new_inst) +{ + ppc_inst_t org_inst; + + if (copy_inst_from_kernel_nofault(&org_inst, ip)) { + pr_err("0x%lx: fetching instruction failed\n", (unsigned long)ip); + return -EFAULT; + } + + if (!ppc_inst_equal(org_inst, old_inst)) { + pr_err("0x%lx: expected (%08lx) != found (%08lx)\n", + (unsigned long)ip, ppc_inst_as_ulong(old_inst), ppc_inst_as_ulong(org_inst)); + return -EINVAL; + } + + if (ppc_inst_equal(old_inst, new_inst)) + return 0; + + return patch_instruction(ip, new_inst); +} + +static void do_isync(void *info __maybe_unused) +{ + isync(); +} + +/* + * A 3-step process for bpf prog entry: + * 1. At bpf prog entry, a single nop/b: + * bpf_func: + * [nop|b] ool_stub + * 2. Out-of-line stub: + * ool_stub: + * mflr r0 + * [b|bl] / + * mtlr r0 // CONFIG_PPC_FTRACE_OUT_OF_LINE only + * b bpf_func + 4 + * 3. Long branch stub: + * long_branch_stub: + * .long / + * mflr r11 + * bcl 20,31,$+4 + * mflr r12 + * ld r12, -16(r12) + * mtctr r12 + * mtlr r11 // needed to retain ftrace ABI + * bctr + * + * dummy_tramp is used to reduce synchronization requirements. + * + * When attaching a bpf trampoline to a bpf prog, we do not need any + * synchronization here since we always have a valid branch target regardless + * of the order in which the above stores are seen. dummy_tramp ensures that + * the long_branch stub goes to a valid destination on other cpus, even when + * the branch to the long_branch stub is seen before the updated trampoline + * address. + * + * However, when detaching a bpf trampoline from a bpf prog, or if changing + * the bpf trampoline address, we need synchronization to ensure that other + * cpus can no longer branch into the older trampoline so that it can be + * safely freed. bpf_tramp_image_put() uses rcu_tasks to ensure all cpus + * make forward progress, but we still need to ensure that other cpus + * execute isync (or some CSI) so that they don't go back into the + * trampoline again. + */ +int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type, + void *old_addr, void *new_addr) +{ + unsigned long bpf_func, bpf_func_end, size, offset; + ppc_inst_t old_inst, new_inst; + int ret = 0, branch_flags; + char name[KSYM_NAME_LEN]; + + if (IS_ENABLED(CONFIG_PPC32)) + return -ENOTSUPP; + + bpf_func = (unsigned long)ip; + branch_flags = poke_type == BPF_MOD_CALL ? BRANCH_SET_LINK : 0; + + /* We currently only support poking bpf programs */ + if (!__bpf_address_lookup(bpf_func, &size, &offset, name)) { + pr_err("%s (0x%lx): kernel/modules are not supported\n", __func__, bpf_func); + return -ENOTSUPP; + } + + /* + * If we are not poking at bpf prog entry, then we are simply patching in/out + * an unconditional branch instruction at im->ip_after_call + */ + if (offset) { + if (poke_type != BPF_MOD_JUMP) { + pr_err("%s (0x%lx): calls are not supported in bpf prog body\n", __func__, + bpf_func); + return -ENOTSUPP; + } + old_inst = ppc_inst(PPC_RAW_NOP()); + if (old_addr) + if (create_branch(&old_inst, ip, (unsigned long)old_addr, 0)) + return -ERANGE; + new_inst = ppc_inst(PPC_RAW_NOP()); + if (new_addr) + if (create_branch(&new_inst, ip, (unsigned long)new_addr, 0)) + return -ERANGE; + mutex_lock(&text_mutex); + ret = bpf_modify_inst(ip, old_inst, new_inst); + mutex_unlock(&text_mutex); + + /* Make sure all cpus see the new instruction */ + smp_call_function(do_isync, NULL, 1); + return ret; + } + + bpf_func_end = bpf_func + size; + + /* Address of the jmp/call instruction in the out-of-line stub */ + ip = (void *)(bpf_func_end - bpf_jit_ool_stub + 4); + + if (!is_offset_in_branch_range((long)ip - 4 - bpf_func)) { + pr_err("%s (0x%lx): bpf prog too large, ool stub out of branch range\n", __func__, + bpf_func); + return -ERANGE; + } + + old_inst = ppc_inst(PPC_RAW_NOP()); + if (old_addr) { + if (is_offset_in_branch_range(ip - old_addr)) + create_branch(&old_inst, ip, (unsigned long)old_addr, branch_flags); + else + create_branch(&old_inst, ip, bpf_func_end - bpf_jit_long_branch_stub, + branch_flags); + } + new_inst = ppc_inst(PPC_RAW_NOP()); + if (new_addr) { + if (is_offset_in_branch_range(ip - new_addr)) + create_branch(&new_inst, ip, (unsigned long)new_addr, branch_flags); + else + create_branch(&new_inst, ip, bpf_func_end - bpf_jit_long_branch_stub, + branch_flags); + } + + mutex_lock(&text_mutex); + + /* + * 1. Update the address in the long branch stub: + * If new_addr is out of range, we will have to use the long branch stub, so patch new_addr + * here. Otherwise, revert to dummy_tramp, but only if we had patched old_addr here. + */ + if ((new_addr && !is_offset_in_branch_range(new_addr - ip)) || + (old_addr && !is_offset_in_branch_range(old_addr - ip))) + ret = patch_ulong((void *)(bpf_func_end - bpf_jit_long_branch_stub - SZL), + (new_addr && !is_offset_in_branch_range(new_addr - ip)) ? + (unsigned long)new_addr : (unsigned long)dummy_tramp); + if (ret) + goto out; + + /* 2. Update the branch/call in the out-of-line stub */ + ret = bpf_modify_inst(ip, old_inst, new_inst); + if (ret) + goto out; + + /* 3. Update instruction at bpf prog entry */ + ip = (void *)bpf_func; + if (!old_addr || !new_addr) { + if (!old_addr) { + old_inst = ppc_inst(PPC_RAW_NOP()); + create_branch(&new_inst, ip, bpf_func_end - bpf_jit_ool_stub, 0); + } else { + new_inst = ppc_inst(PPC_RAW_NOP()); + create_branch(&old_inst, ip, bpf_func_end - bpf_jit_ool_stub, 0); + } + ret = bpf_modify_inst(ip, old_inst, new_inst); + } + +out: + mutex_unlock(&text_mutex); + + /* + * Sync only if we are not attaching a trampoline to a bpf prog so the older + * trampoline can be freed safely. + */ + if (old_addr) + smp_call_function(do_isync, NULL, 1); + + return ret; +} diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c index a0c4f1bde83e..c4db278dae36 100644 --- a/arch/powerpc/net/bpf_jit_comp32.c +++ b/arch/powerpc/net/bpf_jit_comp32.c @@ -127,13 +127,16 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx) { int i; + /* Instruction for trampoline attach */ + EMIT(PPC_RAW_NOP()); + /* Initialize tail_call_cnt, to be skipped if we do tail calls. */ if (ctx->seen & SEEN_TAILCALL) EMIT(PPC_RAW_LI(_R4, 0)); else EMIT(PPC_RAW_NOP()); -#define BPF_TAILCALL_PROLOGUE_SIZE 4 +#define BPF_TAILCALL_PROLOGUE_SIZE 8 if (bpf_has_stack_frame(ctx)) EMIT(PPC_RAW_STWU(_R1, _R1, -BPF_PPC_STACKFRAME(ctx))); @@ -198,6 +201,8 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) bpf_jit_emit_common_epilogue(image, ctx); EMIT(PPC_RAW_BLR()); + + bpf_jit_build_fentry_stubs(image, ctx); } /* Relative offset needs to be calculated based on final image location */ diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index f3be024fc685..dcf339788e58 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -126,6 +126,9 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx) { int i; + /* Instruction for trampoline attach */ + EMIT(PPC_RAW_NOP()); + #ifndef CONFIG_PPC_KERNEL_PCREL if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) EMIT(PPC_RAW_LD(_R2, _R13, offsetof(struct paca_struct, kernel_toc))); @@ -200,6 +203,8 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) EMIT(PPC_RAW_MR(_R3, bpf_to_ppc(BPF_REG_0))); EMIT(PPC_RAW_BLR()); + + bpf_jit_build_fentry_stubs(image, ctx); } int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func) @@ -303,7 +308,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o */ int b2p_bpf_array = bpf_to_ppc(BPF_REG_2); int b2p_index = bpf_to_ppc(BPF_REG_3); - int bpf_tailcall_prologue_size = 8; + int bpf_tailcall_prologue_size = 12; if (!IS_ENABLED(CONFIG_PPC_KERNEL_PCREL) && IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) bpf_tailcall_prologue_size += 4; /* skip past the toc load */