From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x224Dt3GAVFuiFQ+TJUtjK6oMpA/zi1GxXieaAhU0l0SVqqNvqR/uvWMBjj7yLJIZF9kBMtZl ARC-Seal: i=1; a=rsa-sha256; t=1519225242; cv=none; d=google.com; s=arc-20160816; b=YgcJYTt1OdWAgb9n5txjkc/8tDrTuE+w8PSzPwJBosyfjfqxjCsPiKmez+i9zDhDvK DmzI1lefgKSGjul0+IgYkCoez6bxR3fShSLfUSim/RgnHm1bjJuwL9x5QAUUtSNSGMs1 X1RKuVCL9vWU+ZCqKjeQXKOn4+4QwLQxG/pufFw+L6jirbN9OExl08EIDWKoPxy1Owjv 10ucCHNRbLWvLdgkOSMk0bz1baQRRW56qoKKceg6V50VMXwva/tXYwvtxvbNBclNP7wH d6N7aKuhrokTw9H1Fz9+EHpVOjbQpTh61VRshSGAvvz4hvMN0H5TudgJjorQEwlZl7Sp TAIg== 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=TT3M3V61F2B4szGjzqImwNykioOQsGsTWre6tb6jlHE7riyyJJuGRzV1yhYym5fSpX ofkt24Bey8+YdqA+9PvkI+AK+u3QIwOL3CMDA5rZGr6xC2Tr0uPZ8RL0DWTVyLWoMqMk 8BxU4qm8HK04YxSsDOFR9qi76+UxhXkBERtmD/58YMVRk2lstuMMibv3rAyM1ryU/PqC lOzUcjTRybdeTIJI6Sqthzqk8OV22k/wvW9sNevCm+ES3PXvtiuTuhfUAWTBDTnOoZzR Q82b9Wjtwau0PBlyCsIwWCpnuZddZ5jsHGwcwxYUd9gsS69FZDZGLKc4mUh69DzaCysW YTvQ== 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 S938140AbeBUPAa (ORCPT ); Wed, 21 Feb 2018 10:00:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:43262 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933065AbeBUPA0 (ORCPT ); Wed, 21 Feb 2018 10:00:26 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B0EC2178E 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 v2 12/17] x86: ptrace: Add function argument access API Date: Thu, 22 Feb 2018 00:00:02 +0900 Message-Id: <151922520224.6217.12135908633209617079.stgit@devbox> X-Mailer: git-send-email 2.13.6 In-Reply-To: <151922484560.6217.1143686155616343906.stgit@devbox> References: <151922484560.6217.1143686155616343906.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?1593023127489404063?= X-GMAIL-MSGID: =?utf-8?q?1593023127489404063?= 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)