From patchwork Fri Dec 6 00:11:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13896107 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 D8200819; Fri, 6 Dec 2024 00:11:21 +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=1733443882; cv=none; b=Bs1bm8ZMSjtzngt7tF5NJF1JXPN+J/L1/o9Wacb3uiAXBTilo/MwaRyFt9VCeVmV3sxvZbchItnUfbYQ7y0hNcQ6jTmoMsKjKWKvUyQMsMhKV9IfjAHXrG/BUoPRtte/eCU+fIK/RRze1WiGrqLYzvh5CPeK4JW68gmjkjs0xEw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733443882; c=relaxed/simple; bh=IcLMaFOjbxnAA4ujm/xxsUJzK9YIQFWOH3mZCpPMaP8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jUzgU8STiJ83RGx/TJwzq+3FzkpUPusdACDrypxpXsw/5RvjDa93MyPlFtpznQ22G8yX5gihNFsDGBZ4po8MIsf9bOpOmkkEQNwOt4Dc91l00rhbkJcd7IHMl/iMi35Lb7y1aG5mASNbhAGUmfXas0Kz3xEhB4KnUbpgk5o9OeY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QqE6aClu; 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="QqE6aClu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 683F5C4CED1; Fri, 6 Dec 2024 00:11:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733443881; bh=IcLMaFOjbxnAA4ujm/xxsUJzK9YIQFWOH3mZCpPMaP8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QqE6aCluQMeAbUatVTxx8Z8Xj8lLinyTI+ifvjbbWkzICdkdYu/cJj4iExBaMzoqu SL1gwPVEKUTQ/HAr39Q6PhnfvXqTJv6iC2oeteKe/tETqh9eiF6d4Akgf4gJ4itzf0 hVE7MSGF82lx3FZD0Igc3RXglRiiF3A0bW0MGQBoH10NoNbuWV+GVxey8Fj3RJBgEn sdKHmUuLegqqlfaL5wwQlUzY26Czr7Wb9KI1DUGIZfod37/iiXEPMIuKnnk7CoQWk3 vr9uFaiCscK4i226hlPU+PThhIBBIoAeRVpmuO8XehWiVxw24sGedpeMB1/O6J7v3Y +iRDr2judxDNw== From: "Masami Hiramatsu (Google)" To: Alexei Starovoitov , Steven Rostedt , Florent Revest Cc: linux-trace-kernel@vger.kernel.org, LKML , Martin KaFai Lau , bpf , Alexei Starovoitov , Jiri Olsa , Alan Maguire , Mark Rutland , linux-arch@vger.kernel.org, Sven Schnelle Subject: [PATCH v20 11/19] s390/tracing: Enable HAVE_FTRACE_GRAPH_FUNC Date: Fri, 6 Dec 2024 09:11:16 +0900 Message-ID: <173344387598.50709.7225604567319784292.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <173344373580.50709.5332611753907139634.stgit@devnote2> References: <173344373580.50709.5332611753907139634.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Sven Schnelle Add ftrace_graph_func() which is required for fprobe to access registers. This also eliminates the need for calling prepare_ftrace_return() from ftrace_caller(). Signed-off-by: Sven Schnelle --- Changes in v19: - Newly added. --- arch/s390/Kconfig | 1 + arch/s390/include/asm/ftrace.h | 5 ++++ arch/s390/kernel/entry.h | 1 - arch/s390/kernel/ftrace.c | 48 ++++++++++++---------------------------- arch/s390/kernel/mcount.S | 11 --------- 5 files changed, 20 insertions(+), 46 deletions(-) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index d8eee56c10b6..622ea2e9a87e 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -190,6 +190,7 @@ config S390 select HAVE_EFFICIENT_UNALIGNED_ACCESS select HAVE_GUP_FAST select HAVE_FENTRY + select HAVE_FTRACE_GRAPH_FUNC select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_FUNCTION_ERROR_INJECTION diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index 5b7cb49c41ee..fd3f0fe9f7b3 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -39,6 +39,7 @@ struct dyn_arch_ftrace { }; struct module; struct dyn_ftrace; +struct ftrace_ops; bool ftrace_need_init_nop(void); #define ftrace_need_init_nop ftrace_need_init_nop @@ -122,6 +123,10 @@ static inline bool arch_syscall_match_sym_name(const char *sym, return !strcmp(sym + 7, name) || !strcmp(sym + 8, name); } +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs); +#define ftrace_graph_func ftrace_graph_func + #endif /* __ASSEMBLY__ */ #ifdef CONFIG_FUNCTION_TRACER diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h index 21969520f947..a1f28879c87e 100644 --- a/arch/s390/kernel/entry.h +++ b/arch/s390/kernel/entry.h @@ -41,7 +41,6 @@ void do_restart(void *arg); void __init startup_init(void); void die(struct pt_regs *regs, const char *str); int setup_profiling_timer(unsigned int multiplier); -unsigned long prepare_ftrace_return(unsigned long parent, unsigned long sp, unsigned long ip); struct s390_mmap_arg_struct; struct fadvise64_64_args; diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 51439a71e392..c0b2c97efefb 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -261,43 +261,23 @@ void ftrace_arch_code_modify_post_process(void) } #ifdef CONFIG_FUNCTION_GRAPH_TRACER -/* - * Hook the return address and push it in the stack of return addresses - * in current thread info. - */ -unsigned long prepare_ftrace_return(unsigned long ra, unsigned long sp, - unsigned long ip) -{ - if (unlikely(ftrace_graph_is_dead())) - goto out; - if (unlikely(atomic_read(¤t->tracing_graph_pause))) - goto out; - ip -= MCOUNT_INSN_SIZE; - if (!function_graph_enter(ra, ip, 0, (void *) sp)) - ra = (unsigned long) return_to_handler; -out: - return ra; -} -NOKPROBE_SYMBOL(prepare_ftrace_return); -/* - * Patch the kernel code at ftrace_graph_caller location. The instruction - * there is branch relative on condition. To enable the ftrace graph code - * block, we simply patch the mask field of the instruction to zero and - * turn the instruction into a nop. - * To disable the ftrace graph code the mask field will be patched to - * all ones, which turns the instruction into an unconditional branch. - */ -int ftrace_enable_ftrace_graph_caller(void) +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs) { - /* Expect brc 0xf,... */ - return ftrace_patch_branch_mask(ftrace_graph_caller, 0xa7f4, false); -} + unsigned long *parent = &arch_ftrace_regs(fregs)->regs.gprs[14]; + int bit; -int ftrace_disable_ftrace_graph_caller(void) -{ - /* Expect brc 0x0,... */ - return ftrace_patch_branch_mask(ftrace_graph_caller, 0xa704, true); + if (unlikely(ftrace_graph_is_dead())) + return; + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + bit = ftrace_test_recursion_trylock(ip, *parent); + if (bit < 0) + return; + if (!function_graph_enter_regs(*parent, ip, 0, parent, fregs)) + *parent = (unsigned long)&return_to_handler; + ftrace_test_recursion_unlock(bit); } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S index 2b628aa3d809..1fec370fecf4 100644 --- a/arch/s390/kernel/mcount.S +++ b/arch/s390/kernel/mcount.S @@ -104,17 +104,6 @@ SYM_CODE_START(ftrace_common) lgr %r3,%r14 la %r5,STACK_FREGS(%r15) BASR_EX %r14,%r1 -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -# The j instruction gets runtime patched to a nop instruction. -# See ftrace_enable_ftrace_graph_caller. -SYM_INNER_LABEL(ftrace_graph_caller, SYM_L_GLOBAL) - j .Lftrace_graph_caller_end - lmg %r2,%r3,(STACK_FREGS_PTREGS_GPRS+14*8)(%r15) - lg %r4,(STACK_FREGS_PTREGS_PSW+8)(%r15) - brasl %r14,prepare_ftrace_return - stg %r2,(STACK_FREGS_PTREGS_GPRS+14*8)(%r15) -.Lftrace_graph_caller_end: -#endif lg %r0,(STACK_FREGS_PTREGS_PSW+8)(%r15) #ifdef MARCH_HAS_Z196_FEATURES ltg %r1,STACK_FREGS_PTREGS_ORIG_GPR2(%r15)