From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-639720-1527106486-2-15545397104358143434 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no ("Email failed DMARC policy for domain") X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.248, MAILING_LIST_MULTI -1, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org', XOriginatingCountry='CA' X-Spam-charsets: plain='utf-8' X-IgnoreVacation: yes ("Email failed DMARC policy for domain") X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1527106485; b=C475rhKkkWqOf6aHkazk7+6wzHoeUrt2KWan/ixAWZNx3cQSdA AyEsmoNh5Ee0IS4xv3V28N79Hm81jcC1YXeOe85T6bsyxtKaRkB+1PUhzRyFz5c/ GLJwuoYG4bnKBz/VwBUDIFfitbLp8XPR5731X1yUmpEagcPmK2EIMGo9lFwN37ws olji3zS2PJQtRImNfRybq0ujwj8ydWmsgp5enixhQhJK5EZi/LoCdEHT8bAuBTe5 Kjx/frLnxSHdfMqY41/Pb4hH0p6NRO65Zo4fz2aW0/aKMGcpepDeyw5JO5jNxfoZ pwrIkkOkIPhpaZYyPh9lUV21vNe8mZH7UKFA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-type :content-transfer-encoding:sender:list-id; s=fm2; t=1527106485; bh=ZaJEh28WrjkJkMdIYdK5WRX/o5LxyNaG1+tsuEsiIsE=; b=OC/5Wo9fC6jM itBhR5YwMYX3CauOwBXmNBfll1T/pPnBNkMqQfmPZ+Otoi+bNtM9xxQnjadQ78NG IhH+jVCTy9v1rQ2SaVa6RzDxIa3ff+5Tk+vx9SGF+zy6v0CAgJYlZvJZ4i3opyB/ Tgg218m3/NIaY+ZctiY5xlfJCfU8eYZIB5+fzYtJSEmWzNQd3I2ZZaiaPahyIGLz xCs8jHxYuPI33GsHUuiORdSB/VtwlrJz2doE/DqfS8yGIHT6J4AdzAX8h4skEWGc 3luK2GlioPaEqbcIvhMcU2H1/3FY57ULt6bGmlU9r73UtBJVG0Qm5bSU+nVmz95+ SV04GAq6oA== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=fail (body has been altered, 2048-bit rsa key sha256) header.d=efficios.com header.i=@efficios.com header.b=sqbxYvBZ x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=fail (p=none,has-list-id=yes,d=none) header.from=efficios.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=efficios.com header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=fail (body has been altered, 2048-bit rsa key sha256) header.d=efficios.com header.i=@efficios.com header.b=sqbxYvBZ x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=fail (p=none,has-list-id=yes,d=none) header.from=efficios.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=efficios.com header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfEBrDIUwWS32KUbnSgnH8lH7jhfetX8HZ2IcPQmA/K6wPn4DwLYDucgoOK+1IAHkFclLTSbdM/+NKvAUS0xSDk9qPxRs8C/9WKNhoabbSTyT5d/WlWkG 3emuwXLxRdDgDe6r7S+GdcipI0Os4s31ngSY0LyQiVe2ESnjVhmF7nffyfV1VJwa8cnyDXaSadfeHjczEvyvDGrrPIzKKIiXHTXXHTnijf9erRAf87aAdyMI X-CM-Analysis: v=2.3 cv=JLoVTfCb c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=FKkrIqjQGGEA:10 a=alcw4SYXYecA:10 a=IkcTkHD0fZMA:10 a=xqWC_Br6kY4A:10 a=VUJBJC2UJ8kA:10 a=FqpbrowB-PMA:10 a=pGLkceISAAAA:8 a=7d_E57ReAAAA:8 a=VwQbUJbxAAAA:8 a=fOFtUMjIH-rXi4gATtEA:9 a=QEXdDO2ut3YA:10 a=x8gzFH9gYPwA:10 a=jhqOcbufqs7Y1TYCrUUU:22 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934319AbeEWUOm (ORCPT ); Wed, 23 May 2018 16:14:42 -0400 Received: from mail.efficios.com ([167.114.142.138]:40436 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934262AbeEWUOl (ORCPT ); Wed, 23 May 2018 16:14:41 -0400 DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 1FBF9222ED7 Date: Wed, 23 May 2018 16:14:39 -0400 (EDT) From: Mathieu Desnoyers To: Boqun Feng Cc: Will Deacon , Peter Zijlstra , "Paul E. McKenney" , Andy Lutomirski , Dave Watson , linux-kernel , linux-api , Paul Turner , Andrew Morton , Russell King , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Hunter , Andi Kleen , Chris Lameter , Ben Maurer , rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas , Michael Kerrisk , Joel Fernandes , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev Message-ID: <1928158599.1541.1527106479862.JavaMail.zimbra@efficios.com> In-Reply-To: <20180520140811.GB1121@tardis> References: <20180430224433.17407-1-mathieu.desnoyers@efficios.com> <20180516161837.GI12198@hirez.programming.kicks-ass.net> <112970629.1913.1526501596485.JavaMail.zimbra@efficios.com> <20180517011949.GA1121@tardis> <277374719.2144.1526570889798.JavaMail.zimbra@efficios.com> <1526601043.1338308.1376191416.0444B8C5@webmail.messagingengine.com> <418003803.516.1526667437396.JavaMail.zimbra@efficios.com> <20180520140811.GB1121@tardis> Subject: Re: [PATCH 07/14] powerpc: Add support for restartable sequences MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.142.138] X-Mailer: Zimbra 8.8.8_GA_2075 (ZimbraWebClient - FF52 (Linux)/8.8.8_GA_2031) Thread-Topic: powerpc: Add support for restartable sequences Thread-Index: qqWL7CAG0anHYmSjRuZc1e0kK3FL8w== Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: ----- On May 20, 2018, at 10:08 AM, Boqun Feng boqun.feng@gmail.com wrote: > On Fri, May 18, 2018 at 02:17:17PM -0400, Mathieu Desnoyers wrote: >> ----- On May 17, 2018, at 7:50 PM, Boqun Feng boqun.feng@gmail.com wrote: >> [...] >> >> > I think you're right. So we have to introduce callsite to rseq_syscall() >> >> > in syscall path, something like: >> >> > >> >> > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S >> >> > index 51695608c68b..a25734a96640 100644 >> >> > --- a/arch/powerpc/kernel/entry_64.S >> >> > +++ b/arch/powerpc/kernel/entry_64.S >> >> > @@ -222,6 +222,9 @@ system_call_exit: >> >> > mtmsrd r11,1 >> >> > #endif /* CONFIG_PPC_BOOK3E */ >> >> > >> >> > + addi r3,r1,STACK_FRAME_OVERHEAD >> >> > + bl rseq_syscall >> >> > + >> >> > ld r9,TI_FLAGS(r12) >> >> > li r11,-MAX_ERRNO >> >> > andi. >> >> > r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK) >> >> > >> >> By the way, I think this is not the right spot to call rseq_syscall, because >> interrupts are disabled. I think we should move this hunk right after >> system_call_exit. >> > > Good point. > >> Would you like to implement and test an updated patch adding those calls for ppc >> 32 and 64 ? >> > > I'd like to help, but I don't have a handy ppc environment for test... > So I made the below patch which has only been build-tested, hope it > could be somewhat helpful. Hi Boqun, I tried your patch in a ppc64 le environment, and it does not survive boot with CONFIG_DEBUG_RSEQ=y. init gets killed right away. Moreover, I'm not sure that the r3 register don't contain something worth saving before the call on ppc32. Just after there is a "mr" instruction which AFAIU takes r3 as input register. Can you look into it ? Thanks, Mathieu > > Regards, > Boqun > > --------------------------------->8 > Subject: [PATCH] powerpc: Add syscall detection for restartable sequences > > Syscalls are not allowed inside restartable sequences, so add a call to > rseq_syscall() at the very beginning of system call exiting path for > CONFIG_DEBUG_RSEQ=y kernel. This could help us to detect whether there > is a syscall issued inside restartable sequences. > > Signed-off-by: Boqun Feng > --- > arch/powerpc/kernel/entry_32.S | 5 +++++ > arch/powerpc/kernel/entry_64.S | 5 +++++ > 2 files changed, 10 insertions(+) > > diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S > index eb8d01bae8c6..2f134eebe7ed 100644 > --- a/arch/powerpc/kernel/entry_32.S > +++ b/arch/powerpc/kernel/entry_32.S > @@ -365,6 +365,11 @@ syscall_dotrace_cont: > blrl /* Call handler */ > .globl ret_from_syscall > ret_from_syscall: > +#ifdef CONFIG_DEBUG_RSEQ > + /* Check whether the syscall is issued inside a restartable sequence */ > + addi r3,r1,STACK_FRAME_OVERHEAD > + bl rseq_syscall > +#endif > mr r6,r3 > CURRENT_THREAD_INFO(r12, r1) > /* disable interrupts so current_thread_info()->flags can't change */ > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S > index 2cb5109a7ea3..2e2d59bb45d0 100644 > --- a/arch/powerpc/kernel/entry_64.S > +++ b/arch/powerpc/kernel/entry_64.S > @@ -204,6 +204,11 @@ system_call: /* label this so stack traces look sane */ > * This is blacklisted from kprobes further below with _ASM_NOKPROBE_SYMBOL(). > */ > system_call_exit: > +#ifdef CONFIG_DEBUG_RSEQ > + /* Check whether the syscall is issued inside a restartable sequence */ > + addi r3,r1,STACK_FRAME_OVERHEAD > + bl rseq_syscall > +#endif > /* > * Disable interrupts so current_thread_info()->flags can't change, > * and so that we don't get interrupted after loading SRR0/1. > -- > 2.16.2 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: Re: [PATCH 07/14] powerpc: Add support for restartable sequences Date: Wed, 23 May 2018 16:14:39 -0400 (EDT) Message-ID: <1928158599.1541.1527106479862.JavaMail.zimbra@efficios.com> References: <20180430224433.17407-1-mathieu.desnoyers@efficios.com> <20180516161837.GI12198@hirez.programming.kicks-ass.net> <112970629.1913.1526501596485.JavaMail.zimbra@efficios.com> <20180517011949.GA1121@tardis> <277374719.2144.1526570889798.JavaMail.zimbra@efficios.com> <1526601043.1338308.1376191416.0444B8C5@webmail.messagingengine.com> <418003803.516.1526667437396.JavaMail.zimbra@efficios.com> <20180520140811.GB1121@tardis> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180520140811.GB1121@tardis> Sender: linux-kernel-owner@vger.kernel.org To: Boqun Feng Cc: Will Deacon , Peter Zijlstra , "Paul E. McKenney" , Andy Lutomirski , Dave Watson , linux-kernel , linux-api , Paul Turner , Andrew Morton , Russell King , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Hunter , Andi Kleen , Chris Lameter , Ben Maurer , rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas List-Id: linux-api@vger.kernel.org ----- On May 20, 2018, at 10:08 AM, Boqun Feng boqun.feng@gmail.com wrote: > On Fri, May 18, 2018 at 02:17:17PM -0400, Mathieu Desnoyers wrote: >> ----- On May 17, 2018, at 7:50 PM, Boqun Feng boqun.feng@gmail.com wrote: >> [...] >> >> > I think you're right. So we have to introduce callsite to rseq_syscall() >> >> > in syscall path, something like: >> >> > >> >> > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S >> >> > index 51695608c68b..a25734a96640 100644 >> >> > --- a/arch/powerpc/kernel/entry_64.S >> >> > +++ b/arch/powerpc/kernel/entry_64.S >> >> > @@ -222,6 +222,9 @@ system_call_exit: >> >> > mtmsrd r11,1 >> >> > #endif /* CONFIG_PPC_BOOK3E */ >> >> > >> >> > + addi r3,r1,STACK_FRAME_OVERHEAD >> >> > + bl rseq_syscall >> >> > + >> >> > ld r9,TI_FLAGS(r12) >> >> > li r11,-MAX_ERRNO >> >> > andi. >> >> > r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK) >> >> > >> >> By the way, I think this is not the right spot to call rseq_syscall, because >> interrupts are disabled. I think we should move this hunk right after >> system_call_exit. >> > > Good point. > >> Would you like to implement and test an updated patch adding those calls for ppc >> 32 and 64 ? >> > > I'd like to help, but I don't have a handy ppc environment for test... > So I made the below patch which has only been build-tested, hope it > could be somewhat helpful. Hi Boqun, I tried your patch in a ppc64 le environment, and it does not survive boot with CONFIG_DEBUG_RSEQ=y. init gets killed right away. Moreover, I'm not sure that the r3 register don't contain something worth saving before the call on ppc32. Just after there is a "mr" instruction which AFAIU takes r3 as input register. Can you look into it ? Thanks, Mathieu > > Regards, > Boqun > > --------------------------------->8 > Subject: [PATCH] powerpc: Add syscall detection for restartable sequences > > Syscalls are not allowed inside restartable sequences, so add a call to > rseq_syscall() at the very beginning of system call exiting path for > CONFIG_DEBUG_RSEQ=y kernel. This could help us to detect whether there > is a syscall issued inside restartable sequences. > > Signed-off-by: Boqun Feng > --- > arch/powerpc/kernel/entry_32.S | 5 +++++ > arch/powerpc/kernel/entry_64.S | 5 +++++ > 2 files changed, 10 insertions(+) > > diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S > index eb8d01bae8c6..2f134eebe7ed 100644 > --- a/arch/powerpc/kernel/entry_32.S > +++ b/arch/powerpc/kernel/entry_32.S > @@ -365,6 +365,11 @@ syscall_dotrace_cont: > blrl /* Call handler */ > .globl ret_from_syscall > ret_from_syscall: > +#ifdef CONFIG_DEBUG_RSEQ > + /* Check whether the syscall is issued inside a restartable sequence */ > + addi r3,r1,STACK_FRAME_OVERHEAD > + bl rseq_syscall > +#endif > mr r6,r3 > CURRENT_THREAD_INFO(r12, r1) > /* disable interrupts so current_thread_info()->flags can't change */ > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S > index 2cb5109a7ea3..2e2d59bb45d0 100644 > --- a/arch/powerpc/kernel/entry_64.S > +++ b/arch/powerpc/kernel/entry_64.S > @@ -204,6 +204,11 @@ system_call: /* label this so stack traces look sane */ > * This is blacklisted from kprobes further below with _ASM_NOKPROBE_SYMBOL(). > */ > system_call_exit: > +#ifdef CONFIG_DEBUG_RSEQ > + /* Check whether the syscall is issued inside a restartable sequence */ > + addi r3,r1,STACK_FRAME_OVERHEAD > + bl rseq_syscall > +#endif > /* > * Disable interrupts so current_thread_info()->flags can't change, > * and so that we don't get interrupted after loading SRR0/1. > -- > 2.16.2 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com