From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/FupgsuLgnwAmFTKKIX+F/10bE81FeKnXkJdakRKDc3BeIDQ88TAJaU3DTX+ve+3Dds1dk ARC-Seal: i=1; a=rsa-sha256; t=1524658883; cv=none; d=google.com; s=arc-20160816; b=WQqbsWX0URaf3OP8MNYI+RtPaittdKYXmfHFjXBcZlTOm5J8Bh3P2U3+doIByqVUNI +7Bred14pacaeOYYbHqO+ONX73OJuW0tmCVGYqMW5bIl9FC/IXmogKfm3caA5ICBWgOs yamS5PzeuPofsDwj020ZYHP2bWxZ5bRNfGhvmcePP7N8tom32mZTGCX7NjuI1YAp10NK sjyddWJ/bydwvVoY1mRwYfnjY8qw7WZnEI7Ysu7AEwmolsLBd/e20VV8EYy9wqIpsHK8 NzQWluBx0lStXcKmS3UgvqoK+LBzwfCH7m1Eomyn8vj2iG+3aFDzUw3m2FIK41ZCFczR Ngeg== 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=7sUkfpGDBkCU4cP8WaXddLL5R0gSM+6nDRd+CcTf6Sc=; b=oHeC321kqZDWXLflOVVTT04AKyMjhY1p3Ky+9scKZihpmU57Xvs00OQgJcF+fuAhzz ennK4Wu5NtciO1Co6BCS6AFUJN8/Y5J7Qu38xQP55fVh3Cteg+quhJUiL/IxrZS04zVs EV9ltYbFn8ZGtQ+R/7gW6DxeEMYbMscYImMXkCqmbp9nrTuRQY36S/3KvVT0Gx1pJ5BX l7mRbcz/3Y90aoinojQqXrgrV6cwir4Y0FS1DspMtUS+M8NIKJD61MADuGTJj8mMKsKm 3RQU3Eh3tgU9bB0JGQvQl8CHmp1kPCn6vn55PTfoG3gai8QVNQ1PnXfBQCpuiJdHsbIn Umhw== 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 S1753241AbeDYMVW (ORCPT ); Wed, 25 Apr 2018 08:21:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:38370 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752873AbeDYMVV (ORCPT ); Wed, 25 Apr 2018 08:21:21 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58C6321748 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, Ravi Bangoria Subject: [PATCH v7 10/16] x86: ptrace: Add function argument access API Date: Wed, 25 Apr 2018 21:20:57 +0900 Message-Id: <152465885737.26224.2822487520472783854.stgit@devbox> X-Mailer: git-send-email 2.13.6 In-Reply-To: <152465856498.26224.16969986455942749517.stgit@devbox> References: <152465856498.26224.16969986455942749517.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?1598720712556653350?= X-GMAIL-MSGID: =?utf-8?q?1598720712556653350?= 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 8e0d665c8d53..e20c3781b3ca 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 00fcf81f2c56..2d8aaee91694 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -177,6 +177,7 @@ 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)