From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226OEsX9Hb9FZzXoX3K7eEJNIiUog2+qvgxrBsSV5nFyIuI8bX8KyzbAH0SZnDzDAazKvNXJ ARC-Seal: i=1; a=rsa-sha256; t=1519450507; cv=none; d=google.com; s=arc-20160816; b=EGcyVssGvDq7fgnxrN9pL1KmdjN55CodMI6uwG8HaposIqGPnXijNHM0uUMFjXa4Uu jlbGDIV6sDEVZl252WYTSsFw5FazgpXTAD6P7uzmRN3H1FKnJ5ddoyp4HO5X1kBOYxO2 5W5qv1m8JKTFEl0n7YwPuCvVi6yyISZmUlP0MF41s8bPbM+qFilvZEH5rqrdePEPfmDy QSnE5lGQItElGd+o0AsMOE7VTAC+/ywQThz3WG9m5/sximZjD0IE9tR6UU9AAVvuYxdL jjd2AAHAQl1fHSe/HJoCC9VaU/CTtNMwDnq1bZjtpCsRizJtoeTJU1hCNxZBSJYX24M1 hctA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dmarc-filter:arc-authentication-results; bh=UYgdscLlWO/NRE22OSrBcF2hK7ny87xrwSo8tz8mH/0=; b=vTWvGa1obZugduVRzTLykNpXPAZv8D0ERDTNOQN6sxWWs2d3xPp6GdLWFeMxPFlRtU vU/bnztJ059ILIA4pIz+tlUtqDQdlVFvPLV0vi21FE9uFK+vPtDEnx/GCUxZocvZFOW7 ac1Aq7/5bXAgTp4GjbCiKHgWd3nSU51amXpdsBm3votc3/5wDkVMrHWC2pyJhFw4Pw6d sbn8Sbce9yZtsjphoKPCusa+PdFg2lUZjYCH7ePlVwhCIAbrEREn1AA73Y5HZzM/xe2e OhtjcfkEWVZbjPbNdORWE4UmSJIuPX+phRhR5620bSq3JNPjpM1hZR1kuc3jy90fGkSP C2XA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kselftest-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kselftest-owner@vger.kernel.org Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kselftest-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kselftest-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751454AbeBXFfH (ORCPT ); Sat, 24 Feb 2018 00:35:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:45210 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751308AbeBXFfG (ORCPT ); Sat, 24 Feb 2018 00:35:06 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2085E21741 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=mhiramat@kernel.org From: Masami Hiramatsu To: Steven Rostedt , linux-kernel@vger.kernel.org Cc: mhiramat@kernel.org, Ingo Molnar , Namhyung Kim , Tom Zanussi , Arnaldo Carvalho de Melo , linux-trace-users@vger.kernel.org, linux-kselftest@vger.kernel.org, shuah@kernel.org Subject: [PATCH v3 13/18] x86: ptrace: Add function argument access API Date: Sat, 24 Feb 2018 14:34:42 +0900 Message-Id: <151945048211.27508.108330725907416663.stgit@devbox> X-Mailer: git-send-email 2.13.6 In-Reply-To: <151945010287.27508.6226184958678620828.stgit@devbox> References: <151945010287.27508.6226184958678620828.stgit@devbox> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kselftest-owner@vger.kernel.org X-Mailing-List: linux-kselftest@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1593259335581230602?= X-GMAIL-MSGID: =?utf-8?q?1593259335581230602?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Add regs_get_argument() which returns N th argument of the function call. Note that this chooses most probably assignment, in some case it can be incorrect (e.g. passing data structure or floating point etc.) This is expected to be called from kprobes or ftrace with regs where the top of stack is the return address. Signed-off-by: Masami Hiramatsu --- arch/Kconfig | 7 +++++++ arch/x86/Kconfig | 1 + arch/x86/include/asm/ptrace.h | 38 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 46 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 76c0b54443b1..4126ad4b122c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -272,6 +272,13 @@ config HAVE_REGS_AND_STACK_ACCESS_API declared in asm/ptrace.h For example the kprobes-based event tracer needs this API. +config HAVE_FUNCTION_ARG_ACCESS_API + bool + help + This symbol should be selected by an architecure if it supports + the API needed to access function arguments from pt_regs, + declared in asm/ptrace.h + config HAVE_CLK bool help diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 552b3d0eae36..eb0cad381ace 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -176,6 +176,7 @@ config X86 select HAVE_PERF_USER_STACK_DUMP select HAVE_RCU_TABLE_FREE select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION select HAVE_STACK_VALIDATION if X86_64 select HAVE_SYSCALL_TRACEPOINTS diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 6de1fd3d0097..c2304b25e2fd 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -256,6 +256,44 @@ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, return 0; } +/** + * regs_get_kernel_argument() - get Nth function argument in kernel + * @regs: pt_regs of that context + * @n: function argument number (start from 0) + * + * regs_get_argument() returns @n th argument of the function call. + * Note that this chooses most probably assignment, in some case + * it can be incorrect. + * This is expected to be called from kprobes or ftrace with regs + * where the top of stack is the return address. + */ +static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, + unsigned int n) +{ + static const unsigned int argument_offs[] = { +#ifdef __i386__ + offsetof(struct pt_regs, ax), + offsetof(struct pt_regs, cx), + offsetof(struct pt_regs, dx), +#define NR_REG_ARGUMENTS 3 +#else + offsetof(struct pt_regs, di), + offsetof(struct pt_regs, si), + offsetof(struct pt_regs, dx), + offsetof(struct pt_regs, cx), + offsetof(struct pt_regs, r8), + offsetof(struct pt_regs, r9), +#define NR_REG_ARGUMENTS 6 +#endif + }; + + if (n >= NR_REG_ARGUMENTS) { + n -= NR_REG_ARGUMENTS - 1; + return regs_get_kernel_stack_nth(regs, n); + } else + return regs_get_register(regs, argument_offs[n]); +} + #define arch_has_single_step() (1) #ifdef CONFIG_X86_DEBUGCTLMSR #define arch_has_block_step() (1)