From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELsT3WMT3S6nI32zJqoalGhuDIXbATTRNYi4dPthGVt3mgcJCob5EagFo2nw8CdCyrIMouZU ARC-Seal: i=1; a=rsa-sha256; t=1520499018; cv=none; d=google.com; s=arc-20160816; b=mQAWaeKPC1pVlvjSfQS8BFQFPC7hLUFB+98W1p+M+WcyHik7Dh+/ITPb71VMD+XC9Y QBZArecOv5Dmkw051NqnoqnJ7VC7P+PaTfyVN80+/AAj2Fc+W5MUiAdsfRQFbBAIZhHr 3ug5oP+ymqp73z7tWjcSwON23dI+rYsHjkSg+uItV0/SYMoHoORTHqtJGy5ljCyQg0Zs vyaUVvlxwhuqVvTEnhVI5QzZ6YCf+HxHNM1R3oMQw5n0gPvEa9pPaxVZjyHq/LyPg15x 2hjdxZJVTBfrFfvkYMW/ZjyKv3k0xD5C7CzWhDAILvWSBfnoWIP/31gMXn6M9Ht2XLVA DhsQ== 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=i0NcR3XUP6TrIGIIFSX/n6/5mqHuB1u8sZ51Dlk/c50=; b=SICVlaHiXSAbRX62fX7pYDxIHf9wT6scYNVqaeodSoKs7rHNm4FIlq5HZBSBRro99A mi5CCtKoNfD65mIIBGSlbGYieWSSQLNSRCZCMDdwbnE1W4oXsRuEWqN/9dW3DcuFgn94 fmBmFIhrGpilzVFB3DIQZs2pLMgOomJByM5Ol84SgSFpwaQgTB1knWEoRzve7BOtmqcw aA7P0em42WM9BTJV+Cb6/bhgdJtGkFTH1DChFUs9bp95TTx6wr6MZ2pGv2k8T998byyz ABKusOXZgVBUO/QdAkcAxTlc+Fw96hPh2JLGpVcyWGIn7O4QcDW4Njr+CWBJr9Xin8/I N6xQ== 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 S934581AbeCHIuS (ORCPT ); Thu, 8 Mar 2018 03:50:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:50872 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755300AbeCHIuR (ORCPT ); Thu, 8 Mar 2018 03:50:17 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2DADE2133D 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 v5 14/19] x86: ptrace: Add function argument access API Date: Thu, 8 Mar 2018 17:49:53 +0900 Message-Id: <152049899313.7289.13604299638167618228.stgit@devbox> X-Mailer: git-send-email 2.13.6 In-Reply-To: <152049860385.7289.14079393589900496424.stgit@devbox> References: <152049860385.7289.14079393589900496424.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?1594358778642696007?= X-GMAIL-MSGID: =?utf-8?q?1594358778642696007?= 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 18233e459bff..5dde520da3b5 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)