From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B20F4C3A59F for ; Mon, 19 Aug 2019 09:18:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 86A382184E for ; Mon, 19 Aug 2019 09:18:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="Av/fd6Du" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727334AbfHSJST (ORCPT ); Mon, 19 Aug 2019 05:18:19 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:43106 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727218AbfHSJST (ORCPT ); Mon, 19 Aug 2019 05:18:19 -0400 Received: by mail-pl1-f196.google.com with SMTP id 4so676349pld.10 for ; Mon, 19 Aug 2019 02:18:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=EWeFe61NjVZsw0MX6UC+IPTXiHZgyCfddwQtPOe4yOY=; b=Av/fd6DuCqD3aQRAuu8B6WDBiSNYnjii1FPfts2kGCg0+Twyjs8z1xa3zu6MSXgiem tAo6QbpvxAg2KVJEMqHi6UYQACJJ3s9UhZ5MACP9eBB2Al1xVVCEkQMjCrxHvZ8hhJvN yc/7GCDU+oFUp1rTrD9gnsdm8VHs5MN3pgPJJN5sRAlC3T1UbxW2kfXHBelS3eNkg6dT YZB4Giq1av/PaLZxx7E1TDh/FG61CZi35GpdySl8enyYAo1aklP5oo5St3A657Swuujf mjk7ATqw50OHlQ0LOo3AEaQLD32NVM8+dgiayh1JL8tH1CiK55wn/4UV9u9cZAiVi6sM BGgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=EWeFe61NjVZsw0MX6UC+IPTXiHZgyCfddwQtPOe4yOY=; b=LjJnATyvrrDdxPM+5Sc38e2itwBmiMiL1FE0dMgmggKyaMbcbOCaPaPGn0dEIgGdiQ Ign/227ZrAb1nRbT5y7WtpxnzWUVg3vzXawB1s7vxrNsUHKzo+toIc78wrgE1m44SF7Z rXyl/ZsURCnVC9d7fLAGwtLKIybOiKPvXei9+eXdETyQjTcBUixgv3aJPudvFan2rRcX j33S1nIO9Eh4HP0X85wQlSuRb39I0XpsuRWnW+imbPvfCimpN4vfH2DqSc2YWhCJrPsm 5s1smPR5fLh5bnAnnLg79pl+3QW9oNCNvQP1j0RjhRt18XWVcD+PwWarzK4xUQYH0vKy pbxg== X-Gm-Message-State: APjAAAXFncf3of9TqVfbZYoKa9ADGWulcGbVsKlOupy8ch8Mlir0NaqT 8UZubB4lHd7vD0dx5qIURr1jFw== X-Google-Smtp-Source: APXvYqxHZbQ6AKILK5r1gXP12qaqsKkN+4COxNlst8U8XzfUTS8V/tZT8lHFRS6rP/NugHkoh1oHyw== X-Received: by 2002:a17:902:2bc5:: with SMTP id l63mr19077218plb.239.1566206298095; Mon, 19 Aug 2019 02:18:18 -0700 (PDT) Received: from leoy-ThinkPad-X240s (li456-16.members.linode.com. [50.116.10.16]) by smtp.gmail.com with ESMTPSA id d2sm11867796pjs.21.2019.08.19.02.18.11 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 19 Aug 2019 02:18:17 -0700 (PDT) Date: Mon, 19 Aug 2019 17:18:08 +0800 From: Leo Yan To: Russell King , Oleg Nesterov , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , "Naveen N. Rao" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, clang-built-linux@googlegroups.com, Masami Hiramatsu Subject: Re: [PATCH v2 3/3] arm: Add support for function error injection Message-ID: <20190819091808.GB5599@leoy-ThinkPad-X240s> References: <20190806100015.11256-1-leo.yan@linaro.org> <20190806100015.11256-4-leo.yan@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190806100015.11256-4-leo.yan@linaro.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Russell, On Tue, Aug 06, 2019 at 06:00:15PM +0800, Leo Yan wrote: > This patch implements arm specific functions regs_set_return_value() and > override_function_with_return() to support function error injection. > > In the exception flow, it updates pt_regs::ARM_pc with pt_regs::ARM_lr > so can override the probed function return. Gentle ping ... Could you review this patch? Thanks, Leo. > Signed-off-by: Leo Yan > --- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/ptrace.h | 5 +++++ > arch/arm/lib/Makefile | 2 ++ > arch/arm/lib/error-inject.c | 19 +++++++++++++++++++ > 4 files changed, 27 insertions(+) > create mode 100644 arch/arm/lib/error-inject.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 33b00579beff..2d3d44a037f6 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -77,6 +77,7 @@ config ARM > select HAVE_EXIT_THREAD > select HAVE_FAST_GUP if ARM_LPAE > select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL > + select HAVE_FUNCTION_ERROR_INJECTION if !THUMB2_KERNEL > select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG > select HAVE_FUNCTION_TRACER if !XIP_KERNEL > select HAVE_GCC_PLUGINS > diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h > index 91d6b7856be4..3b41f37b361a 100644 > --- a/arch/arm/include/asm/ptrace.h > +++ b/arch/arm/include/asm/ptrace.h > @@ -89,6 +89,11 @@ static inline long regs_return_value(struct pt_regs *regs) > return regs->ARM_r0; > } > > +static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) > +{ > + regs->ARM_r0 = rc; > +} > + > #define instruction_pointer(regs) (regs)->ARM_pc > > #ifdef CONFIG_THUMB2_KERNEL > diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile > index b25c54585048..8f56484a7156 100644 > --- a/arch/arm/lib/Makefile > +++ b/arch/arm/lib/Makefile > @@ -42,3 +42,5 @@ ifeq ($(CONFIG_KERNEL_MODE_NEON),y) > CFLAGS_xor-neon.o += $(NEON_FLAGS) > obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o > endif > + > +obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o > diff --git a/arch/arm/lib/error-inject.c b/arch/arm/lib/error-inject.c > new file mode 100644 > index 000000000000..2d696dc94893 > --- /dev/null > +++ b/arch/arm/lib/error-inject.c > @@ -0,0 +1,19 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include > +#include > + > +void override_function_with_return(struct pt_regs *regs) > +{ > + /* > + * 'regs' represents the state on entry of a predefined function in > + * the kernel/module and which is captured on a kprobe. > + * > + * 'regs->ARM_lr' contains the the link register for the probed > + * function, when kprobe returns back from exception it will override > + * the end of probed function and directly return to the predefined > + * function's caller. > + */ > + instruction_pointer_set(regs, regs->ARM_lr); > +} > +NOKPROBE_SYMBOL(override_function_with_return); > -- > 2.17.1 >