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 AB2AFC76191 for ; Thu, 25 Jul 2019 01:49:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84F372190F for ; Thu, 25 Jul 2019 01:49:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="NEk+K/M4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388547AbfGYBtF (ORCPT ); Wed, 24 Jul 2019 21:49:05 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:39797 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388445AbfGYBtF (ORCPT ); Wed, 24 Jul 2019 21:49:05 -0400 Received: by mail-pg1-f194.google.com with SMTP id u17so22125841pgi.6 for ; Wed, 24 Jul 2019 18:49:04 -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=jiFDcwQiGaN6vJB6KlbsTelIXNEPU4EhhSM8eaDwe28=; b=NEk+K/M4XoXRNkaimXAp55fFnW3FG5JYc3y4ElmVcnygNevbCkm7g12T2gZIawjH2m ervX0znf3v+LokRvX8HvRYRZl/+E9WIpAoEOw7CYj2MriWSfdJygVGODxCuUvmiXdEXX RxDDWIzRbhS1RMdFp9h7dgJ5HPvZOYNZiOC0FrRLge9QjYDB9mZb32tTG9bnJ4J1Cwlf 9zFbjngKQdACK2PH8tc2nnDIp0V5gB6EXixQ18pjnff+elGrh5duFnjWXbo2SlVAz9e/ jSE3gdzud8A+T/nJBAC8R4eyxE9JDvqa7P4h1FWmp3l493GQEiQ/xOG7MRT1m9wLsv3d Rb0Q== 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=jiFDcwQiGaN6vJB6KlbsTelIXNEPU4EhhSM8eaDwe28=; b=Yj/NLWGa2so5bBRtMKZuuN18yiObVJcac96sxIrognmBAexJngjaUpon1BbHqkE4CB 7nBE1wrnUSJjGV4ndZO04accPPFTA329MuTZDwjxTby1ePeH/+OaYzHQo1cVBCTLQMU1 0r6vjnh+gYBROtEAX9G3Ef207IHPlT6jgwyutRMRxS9XynGM6wo53S1d03QtBFE0dvzR qFR9xkMI0wJVwXJYZOnyvaYfZwKqLdP9dKKYzAEV0qGonzgDtodJXZ5Bnx23ARm+qhsu cFcQEAski41D591v/Vgv4K4BKYzgrl7kFN7X/SHmPypd48QMkPxi6Fi2iTq0+tXAPcmj NJOw== X-Gm-Message-State: APjAAAUFlg7AOZsHllJywx9AsqAPrK8RL/xMae0eww3KxHrOrw7XJNJ2 0W6y/zyBP9cz/p5BXxCsnALMsA== X-Google-Smtp-Source: APXvYqw8jGLemfwZZMgQ9iTqUNH6yOhQwK3TZ3iENKJ2ax2lB0hZ9iGxiJLocXHtOSry7RDr1MmsXw== X-Received: by 2002:a65:5144:: with SMTP id g4mr31637451pgq.202.1564019344033; Wed, 24 Jul 2019 18:49:04 -0700 (PDT) Received: from leoy-ThinkPad-X240s ([240e:e0:f090:3aa1:9c84:f7b8:9214:6096]) by smtp.gmail.com with ESMTPSA id e124sm75939006pfh.181.2019.07.24.18.48.45 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 24 Jul 2019 18:49:03 -0700 (PDT) Date: Thu, 25 Jul 2019 09:48:32 +0800 From: Leo Yan To: Russell King , Oleg Nesterov , Catalin Marinas , Will Deacon , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Masami Hiramatsu , Justin He Subject: Re: [PATCH 2/2] arm: Add support for function error injection Message-ID: <20190725014416.GC6764@leoy-ThinkPad-X240s> References: <20190716111301.1855-1-leo.yan@linaro.org> <20190716111301.1855-3-leo.yan@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190716111301.1855-3-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, Jul 16, 2019 at 07:13:01PM +0800, Leo Yan wrote: > This patch implement regs_set_return_value() and > override_function_with_return() to support function error injection > for arm. > > In the exception flow, we can update pt_regs::ARM_pc with > pt_regs::ARM_lr so that can override the probed function return. Gentle ping. > Signed-off-by: Leo Yan > --- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/error-injection.h | 13 +++++++++++++ > arch/arm/include/asm/ptrace.h | 5 +++++ > arch/arm/lib/Makefile | 2 ++ > arch/arm/lib/error-inject.c | 19 +++++++++++++++++++ > 5 files changed, 40 insertions(+) > create mode 100644 arch/arm/include/asm/error-injection.h > create mode 100644 arch/arm/lib/error-inject.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 8869742a85df..f7932a5e29ea 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -74,6 +74,7 @@ config ARM > select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU > select HAVE_EXIT_THREAD > 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/error-injection.h b/arch/arm/include/asm/error-injection.h > new file mode 100644 > index 000000000000..da057e8ed224 > --- /dev/null > +++ b/arch/arm/include/asm/error-injection.h > @@ -0,0 +1,13 @@ > +/* SPDX-License-Identifier: GPL-2.0+ */ > + > +#ifndef __ASM_ERROR_INJECTION_H_ > +#define __ASM_ERROR_INJECTION_H_ > + > +#include > +#include > +#include > +#include > + > +void override_function_with_return(struct pt_regs *regs); > + > +#endif /* __ASM_ERROR_INJECTION_H_ */ > 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 0bff0176db2c..d3d7430ecd76 100644 > --- a/arch/arm/lib/Makefile > +++ b/arch/arm/lib/Makefile > @@ -43,3 +43,5 @@ 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..96319d017114 > --- /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 and assign it to 'regs->ARM_pc', so when kprobe returns > + * back from exception it will override the end of probed function > + * and drirectly return to the predefined function's caller. > + */ > + regs->ARM_pc = regs->ARM_lr; > +} > +NOKPROBE_SYMBOL(override_function_with_return); > -- > 2.17.1 >