From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227IdXWUrguwfGSQ6rbT22ZauG1rHNEBDV1yig3OM2U1/VT4XXkIvLq7tRZTL0t3NUVZRg7D ARC-Seal: i=1; a=rsa-sha256; t=1519788412; cv=none; d=google.com; s=arc-20160816; b=Mg/mBqnAhsEbp66AHEOzUp36ad95RD6RPkeHMBuLOglIIZ9LVpTkN8/kwyXtAVueHG Hn2Jxm4RiZ4N+5uG8xuknH7/VMep/pWI0ua9VeZU5UyQfcJp8O0ksM4940tzTsD0Swqp NKlhJpMwIsBxHIgzVN77ZrG/EHV1dyjepo9qSPPJRRR4mog91AJITCBAtFZ3BbToP5nI r4IZWzf2iItuSwYrNgaK8JNqIxzUSf5qSKQJIPQ183AHdjBv6l+IcSu6Sd6qt8Nt9vxf Q0geVl0Ukk950uNoF3l0ezHPRjFMvBeHcftJdlXOUIdIctuITpZqsGMlmAhxF9/nQYD3 b8WA== 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=Bu6z+M/A4lXmHbl2uamOuXuBzOFhDP+hcf81yuJgx9Y=; b=0YnSyU/Jy/B3jiBMOMDwEAvRNAfATvM/l/Wk01V3MaOvMKppfYZCIMEwZbzAL/TH5C Q/ETn43Z/KbkPt3PnDxLgVCKoTosTRMCRQm+oFSGImkLK7vUb+Smz6qr4lW7EvIJ9neJ aInxgAH7qYnBx6xpHP4QxZYsTWbpWUOK75Zl1NjSHGmAphx9+rUizbpI7d9rT9h5PmPd LbS8I/WH3HioyhP1H1oW74WD5dmun8AFqfaFll98mAXkYsRPrVddfVxNfi6byhwxCqf7 0NJyhbBF2LUGF6KG4hFtZWL4FgkQKQOcVOQm/IJyfTr06JNkBCgUbrMTbYWzyrXuUw6/ bLjg== 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 S1751682AbeB1D0k (ORCPT ); Tue, 27 Feb 2018 22:26:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:56616 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453AbeB1D0j (ORCPT ); Tue, 27 Feb 2018 22:26:39 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B7552133D 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 v4 14/19] x86: ptrace: Add function argument access API Date: Wed, 28 Feb 2018 12:26:15 +0900 Message-Id: <151978837500.2577.1096284635519642144.stgit@devbox> X-Mailer: git-send-email 2.13.6 In-Reply-To: <151978796240.2577.6531711990653677529.stgit@devbox> References: <151978796240.2577.6531711990653677529.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?1593613654431307008?= X-GMAIL-MSGID: =?utf-8?q?1593613654431307008?= 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 bdfd503065d3..d7e6d93968ea 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)