From patchwork Wed Jan 12 14:03:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 12711440 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32B36C433EF for ; Wed, 12 Jan 2022 14:03:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353892AbiALODw (ORCPT ); Wed, 12 Jan 2022 09:03:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353897AbiALODp (ORCPT ); Wed, 12 Jan 2022 09:03:45 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C224FC061759; Wed, 12 Jan 2022 06:03:41 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8BC1FB81EF6; Wed, 12 Jan 2022 14:03:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E06E2C36AEA; Wed, 12 Jan 2022 14:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641996219; bh=tzqau06Ug3zjELYtX9vo3t11Cd6xCmSb0rhMW9gNyRk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NSol9FqSp90Pt70uE+RZ4DXjYgV+L26W0oXWk7RZU0YlCrTkyeoxLQ1cLRIM/3WsQ bT5AcQSr72by6bM09S4eiJt9sWstug8p0C9R9w02GUE4zaOGr3+Kz9OjVmw2a/DhIk 9uV4ozdPpD93DcD7aai2loI59JM5uRO4o5EddLOMni0nsImUN/ZcJ0TgcRuLWwOaYa rGx5GABmIxJbuKoYt5Iy5VQflgLPV7m9wr8q44O9Kw7WkI8l4NBTkHVrEUMJEzkQ/K so9l7OCQ+NQU6p2ckMxEhwG5ckE6PweAVzJHB7IWYMn86SRayJJ9OfyAtwcAvmNqOX nkPrnP6ZhiMMQ== From: Masami Hiramatsu To: Jiri Olsa , Alexei Starovoitov Cc: Daniel Borkmann , Andrii Nakryiko , Masami Hiramatsu , netdev@vger.kernel.org, bpf@vger.kernel.org, lkml , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Steven Rostedt , "Naveen N . Rao" , Anil S Keshavamurthy , "David S . Miller" Subject: [RFC PATCH v2 4/8] rethook: x86: Add rethook x86 implementation Date: Wed, 12 Jan 2022 23:03:33 +0900 Message-Id: <164199621352.1247129.832357773512186691.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <164199616622.1247129.783024987490980883.stgit@devnote2> References: <164199616622.1247129.783024987490980883.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-State: RFC Add rethook for x86 implementation. Most of the code has been copied from kretprobes on x86. Signed-off-by: Masami Hiramatsu --- arch/x86/Kconfig | 1 arch/x86/kernel/Makefile | 1 arch/x86/kernel/rethook.c | 115 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 117 insertions(+) create mode 100644 arch/x86/kernel/rethook.c diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 7399327d1eff..939c4c897e63 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -219,6 +219,7 @@ config X86 select HAVE_KPROBES_ON_FTRACE select HAVE_FUNCTION_ERROR_INJECTION select HAVE_KRETPROBES + select HAVE_RETHOOK select HAVE_KVM select HAVE_LIVEPATCH if X86_64 select HAVE_MIXED_BREAKPOINTS_REGS diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 2ff3e600f426..66593d8c4d74 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -106,6 +106,7 @@ obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o obj-$(CONFIG_X86_TSC) += trace_clock.o obj-$(CONFIG_TRACING) += trace.o +obj-$(CONFIG_RETHOOK) += rethook.o obj-$(CONFIG_CRASH_CORE) += crash_core_$(BITS).o obj-$(CONFIG_KEXEC_CORE) += machine_kexec_$(BITS).o obj-$(CONFIG_KEXEC_CORE) += relocate_kernel_$(BITS).o crash.o diff --git a/arch/x86/kernel/rethook.c b/arch/x86/kernel/rethook.c new file mode 100644 index 000000000000..f2f3b9526e43 --- /dev/null +++ b/arch/x86/kernel/rethook.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * x86 implementation of rethook. Mostly copied from arch/x86/kernel/kprobes/core.c. + */ +#include +#include +#include + +#include "kprobes/common.h" + +/* + * Called from arch_rethook_trampoline + */ +__used __visible void arch_rethook_trampoline_callback(struct pt_regs *regs) +{ + unsigned long *frame_pointer; + + /* fixup registers */ + regs->cs = __KERNEL_CS; +#ifdef CONFIG_X86_32 + regs->gs = 0; +#endif + regs->ip = (unsigned long)&arch_rethook_trampoline; + regs->orig_ax = ~0UL; + regs->sp += sizeof(long); + frame_pointer = ®s->sp + 1; + + /* + * The return address at 'frame_pointer' is recovered by the + * arch_rethook_fixup_return() which called from this + * rethook_trampoline_handler(). + */ + rethook_trampoline_handler(regs, (unsigned long)frame_pointer); + + /* + * Copy FLAGS to 'pt_regs::sp' so that arch_rethook_trapmoline() + * can do RET right after POPF. + */ + regs->sp = regs->flags; +} +NOKPROBE_SYMBOL(arch_rethook_trampoline_callback); + +/* + * When a target function returns, this code saves registers and calls + * arch_rethook_trampoline_callback(), which calls the rethook handler. + */ +asm( + ".text\n" + ".global arch_rethook_trampoline\n" + ".type arch_rethook_trampoline, @function\n" + "arch_rethook_trampoline:\n" +#ifdef CONFIG_X86_64 + /* Push a fake return address to tell the unwinder it's a kretprobe. */ + " pushq $arch_rethook_trampoline\n" + UNWIND_HINT_FUNC + /* Save the 'sp - 8', this will be fixed later. */ + " pushq %rsp\n" + " pushfq\n" + SAVE_REGS_STRING + " movq %rsp, %rdi\n" + " call arch_rethook_trampoline_callback\n" + RESTORE_REGS_STRING + /* In the callback function, 'regs->flags' is copied to 'regs->sp'. */ + " addq $8, %rsp\n" + " popfq\n" +#else + /* Push a fake return address to tell the unwinder it's a kretprobe. */ + " pushl $arch_rethook_trampoline\n" + UNWIND_HINT_FUNC + /* Save the 'sp - 4', this will be fixed later. */ + " pushl %esp\n" + " pushfl\n" + SAVE_REGS_STRING + " movl %esp, %eax\n" + " call arch_rethook_trampoline_callback\n" + RESTORE_REGS_STRING + /* In the callback function, 'regs->flags' is copied to 'regs->sp'. */ + " addl $4, %esp\n" + " popfl\n" +#endif + " ret\n" + ".size arch_rethook_trampoline, .-arch_rethook_trampoline\n" +); +NOKPROBE_SYMBOL(arch_rethook_trampoline); +/* + * arch_rethook_trampoline() skips updating frame pointer. The frame pointer + * saved in arch_rethook_trampoline_callback() points to the real caller + * function's frame pointer. Thus the arch_rethook_trampoline() doesn't have + * a standard stack frame with CONFIG_FRAME_POINTER=y. + * Let's mark it non-standard function. Anyway, FP unwinder can correctly + * unwind without the hint. + */ +STACK_FRAME_NON_STANDARD_FP(arch_rethook_trampoline); + +/* This is called from rethook_trampoline_handler(). */ +void arch_rethook_fixup_return(struct pt_regs *regs, + unsigned long correct_ret_addr) +{ + unsigned long *frame_pointer = ®s->sp + 1; + + /* Replace fake return address with real one. */ + *frame_pointer = correct_ret_addr; +} + +void arch_rethook_prepare(struct rethook_node *rh, struct pt_regs *regs) +{ + unsigned long *stack = (unsigned long *)regs->sp; + + rh->ret_addr = stack[0]; + rh->frame = regs->sp; + + /* Replace the return addr with trampoline addr */ + stack[0] = (unsigned long) arch_rethook_trampoline; +} +NOKPROBE_SYMBOL(arch_rethook_prepare);