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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 4B546C10F00 for ; Mon, 18 Mar 2019 14:57:27 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C9F6F20872 for ; Mon, 18 Mar 2019 14:57:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C9F6F20872 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44NK6D3gsPzDqJB for ; Tue, 19 Mar 2019 01:57:24 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=arm.com (client-ip=217.140.101.70; helo=foss.arm.com; envelope-from=sudeep.holla@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by lists.ozlabs.org (Postfix) with ESMTP id 44NK474dj3zDqHl for ; Tue, 19 Mar 2019 01:55:34 +1100 (AEDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2E6301650; Mon, 18 Mar 2019 07:55:32 -0700 (PDT) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3873D3F59C; Mon, 18 Mar 2019 07:55:29 -0700 (PDT) Date: Mon, 18 Mar 2019 14:55:23 +0000 From: Sudeep Holla To: "Dmitry V. Levin" Subject: Re: [PATCH v2 2/6] ptrace: introduce ptrace_syscall_enter to consolidate PTRACE_SYSEMU handling Message-ID: <20190318145523.GA18196@e107155-lin> References: <20190318104925.16600-1-sudeep.holla@arm.com> <20190318104925.16600-3-sudeep.holla@arm.com> <20190318143147.GB27941@altlinux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190318143147.GB27941@altlinux.org> User-Agent: Mutt/1.9.4 (2018-02-28) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Haibo Xu , Steve Capper , Catalin Marinas , jdike@addtoit.com, x86@kernel.org, Will Deacon , linux-kernel@vger.kernel.org, Oleg Nesterov , Richard Weinberger , Ingo Molnar , Paul Mackerras , Andy Lutomirski , Thomas Gleixner , Bin Lu , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Mar 18, 2019 at 05:31:47PM +0300, Dmitry V. Levin wrote: > On Mon, Mar 18, 2019 at 10:49:21AM +0000, Sudeep Holla wrote: > > Currently each architecture handles PTRACE_SYSEMU in very similar way. > > It's completely arch independent and can be handled in the code helping > > to consolidate PTRACE_SYSEMU handling. > > > > Let's introduce a hook 'ptrace_syscall_enter' that arch specific syscall > > entry code can call. > > > > Cc: Oleg Nesterov > > Signed-off-by: Sudeep Holla > > --- > > include/linux/ptrace.h | 1 + > > kernel/ptrace.c | 22 ++++++++++++++++++++++ > > 2 files changed, 23 insertions(+) > > > > diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h > > index edb9b040c94c..e30f51e3363e 100644 > > --- a/include/linux/ptrace.h > > +++ b/include/linux/ptrace.h > > @@ -407,6 +407,7 @@ static inline void user_single_step_report(struct pt_regs *regs) > > #define current_user_stack_pointer() user_stack_pointer(current_pt_regs()) > > #endif > > > > +extern long ptrace_syscall_enter(struct pt_regs *regs); > > extern int task_current_syscall(struct task_struct *target, long *callno, > > unsigned long args[6], unsigned int maxargs, > > unsigned long *sp, unsigned long *pc); > > diff --git a/kernel/ptrace.c b/kernel/ptrace.c > > index 4fa3b7f4c3c7..c9c505c483df 100644 > > --- a/kernel/ptrace.c > > +++ b/kernel/ptrace.c > > @@ -29,6 +29,7 @@ > > #include > > #include > > #include > > +#include > > > > /* > > * Access another process' address space via ptrace. > > @@ -557,6 +558,27 @@ static int ptrace_detach(struct task_struct *child, unsigned int data) > > return 0; > > } > > > > +/* > > + * Hook to check and report for PTRACE_SYSEMU, can be called from arch > > + * arch syscall entry code > > + */ > > +long ptrace_syscall_enter(struct pt_regs *regs) > > +{ > > +#ifdef TIF_SYSCALL_EMU > > + if (test_thread_flag(TIF_SYSCALL_EMU)) { > > + if (tracehook_report_syscall_entry(regs)) > > + /* > > + * We can ignore the return code here as we need > > + * return -1 always for syscall emulation irrespective > > + * of whether the tracehook report fails or succeed. > > + */ > > + ; > > This is problematic as it causes build errors with -Werror=empty-body, > see https://lore.kernel.org/lkml/20181218205305.26647-1-malat@debian.org/ > Thanks for the pointer, will update. -- Regards, Sudeep