From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-936554-1527123822-2-16016494980735649452 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, 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='au', MailFrom='org' X-Spam-charsets: 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= 1527123821; b=GcKZn2nYR8IBWKyWflTpzqu5a6FaAvUOujTHLqES4gN6f1VVLf JCpJf/6JGZYWFDzp0LFo5E/JKwe5EF23sLb4SW2/V6auvNMJ9M/MVMyM/RDXvxJ0 QCdSWIf2j6+CXB4XB2WSIt+uIsi08i458rWm9TZku4n7UF2WPfmQVw38qf1GX4dF rRsS5wwrqVVMLGNB7fCYA56JKWcZd+dFTVqZb4iYHCyim7E4Y68QDa0QsNkoXyYb hc/GDLg4radxOLGrIAdkx2+Qa9L2cUhWgfSV87mSZBtyOTLQ6arf5mCAO5Rw6bQm wLjrc8+g3h4ul1SdzeGlVAIVeHsU8H3Yab7A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:in-reply-to:references :date:message-id:mime-version:content-type:sender:list-id; s= fm2; t=1527123821; bh=97pcmgHz19I/PTa9GUBZk8/fQeT4eiH5BsWlxRBy7e o=; b=hOTAot4RjAxJr+dkO9SdXVa0HQWORY6OAIUaTOv7wt550XyqTXnd0nXfFf QuTiFsSkRLb6F2STHAQWyo2U1DCFROvSmxUjb4R/zF2HGEJSwpAAz1Pjod0apmST RfbiT8yVcvEluThMx9i8Yj1A4NLlD7x1qS9R3q334DSjSD31sSdgjZoREX/0h7zU zpjjtYbnQYeInRlqmZtBSAIHdgVkgCVKlbBWZDL5iZezzV+rJlwesXrrRY8XvgdF JP2lWWhn3VC0SsuOG85xANr3vMpYtx1epNzCz0P9Vlq4MW3NQP3/7n+NRoECUo+7 FOvSbBkYL9QhvnGvC//Wl5knCzrg== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=ellerman.id.au; 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=ellerman.id.au 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=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=ellerman.id.au; 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=ellerman.id.au header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfJ4rAHmiYgljFANRi7kK+Uf55C02oLc+u7zVfZCme7iFz2UuB+pxbcYETyfWQV6lvWfcUkhz3dSenpSfiBRi80UVVsFq7AEujGVzIeWVES9YMZtFzq69 kbVLzJwmy3sgSkp30qoEQPiaiHxtCrm1dEzu2HYKupG3Ew/UWtaDxLu0R2eYe2fm8NRgRCyhx1aqwJeQSZjAORhnXMzpZyEMT2WgOD6xGopPsR6RAsw77UX9 X-CM-Analysis: v=2.3 cv=JLoVTfCb c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=VUJBJC2UJ8kA:10 a=7d_E57ReAAAA:8 a=Ixqt2FsUAAAA:8 a=VwQbUJbxAAAA:8 a=VDRPkFbQ9hqd-elkI78A:9 a=xtgkuJUu8JAA:10 a=x8gzFH9gYPwA:10 a=9eWGACQJV1QA:10 a=jhqOcbufqs7Y1TYCrUUU:22 a=wbNHd7AAyUN6gYWAVcba: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 S935263AbeEXBDj (ORCPT ); Wed, 23 May 2018 21:03:39 -0400 Received: from ozlabs.org ([203.11.71.1]:40887 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935260AbeEXBDi (ORCPT ); Wed, 23 May 2018 21:03:38 -0400 Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au From: Michael Ellerman To: Mathieu Desnoyers , 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 , linuxppc-dev Subject: Re: [PATCH 07/14] powerpc: Add support for restartable sequences In-Reply-To: <37442352.1577.1527110985175.JavaMail.zimbra@efficios.com> References: <20180430224433.17407-1-mathieu.desnoyers@efficios.com> <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> <1928158599.1541.1527106479862.JavaMail.zimbra@efficios.com> <37442352.1577.1527110985175.JavaMail.zimbra@efficios.com> Date: Thu, 24 May 2018 11:03:29 +1000 Message-ID: <87o9h5sw4e.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain 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: Mathieu Desnoyers writes: > ----- On May 23, 2018, at 4:14 PM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: ... >> >> 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. Sorry this code is super gross and hard to deal with. > The following fixup gets ppc64 to work: > > --- a/arch/powerpc/kernel/entry_64.S > +++ b/arch/powerpc/kernel/entry_64.S > @@ -208,6 +208,7 @@ system_call_exit: > /* Check whether the syscall is issued inside a restartable sequence */ > addi r3,r1,STACK_FRAME_OVERHEAD > bl rseq_syscall > + ld r3,RESULT(r1) > #endif > /* > * Disable interrupts so current_thread_info()->flags can't change, I don't think that's safe. If you look above that, we have r3, r8 and r12 all live: .Lsyscall_exit: std r3,RESULT(r1) CURRENT_THREAD_INFO(r12, r1) ld r8,_MSR(r1) #ifdef CONFIG_PPC_BOOK3S /* No MSR:RI on BookE */ andi. r10,r8,MSR_RI beq- .Lunrecov_restore #endif They're all volatile across function calls: http://openpowerfoundation.org/wp-content/uploads/resources/leabi/content/dbdoclet.50655240_68174.html The system_call_exit symbol is actually there for kprobes and cosmetic purposes. The actual syscall return flow starts at .Lsyscall_exit. So I think this would work: diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index db4df061c33a..e19f377a25e0 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -184,6 +184,14 @@ system_call: /* label this so stack traces look sane */ .Lsyscall_exit: std r3,RESULT(r1) + +#ifdef CONFIG_DEBUG_RSEQ + /* Check whether the syscall is issued inside a restartable sequence */ + addi r3,r1,STACK_FRAME_OVERHEAD + bl rseq_syscall + ld r3,RESULT(r1) +#endif + CURRENT_THREAD_INFO(r12, r1) ld r8,_MSR(r1) I'll try and get this series into my test setup at some point, been a bit busy lately :) cheers From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Ellerman Subject: Re: [PATCH 07/14] powerpc: Add support for restartable sequences Date: Thu, 24 May 2018 11:03:29 +1000 Message-ID: <87o9h5sw4e.fsf@concordia.ellerman.id.au> References: <20180430224433.17407-1-mathieu.desnoyers@efficios.com> <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> <1928158599.1541.1527106479862.JavaMail.zimbra@efficios.com> <37442352.1577.1527110985175.JavaMail.zimbra@efficios.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <37442352.1577.1527110985175.JavaMail.zimbra@efficios.com> Sender: linux-kernel-owner@vger.kernel.org To: Mathieu Desnoyers , 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 Mathieu Desnoyers writes: > ----- On May 23, 2018, at 4:14 PM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: ... >> >> 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. Sorry this code is super gross and hard to deal with. > The following fixup gets ppc64 to work: > > --- a/arch/powerpc/kernel/entry_64.S > +++ b/arch/powerpc/kernel/entry_64.S > @@ -208,6 +208,7 @@ system_call_exit: > /* Check whether the syscall is issued inside a restartable sequence */ > addi r3,r1,STACK_FRAME_OVERHEAD > bl rseq_syscall > + ld r3,RESULT(r1) > #endif > /* > * Disable interrupts so current_thread_info()->flags can't change, I don't think that's safe. If you look above that, we have r3, r8 and r12 all live: .Lsyscall_exit: std r3,RESULT(r1) CURRENT_THREAD_INFO(r12, r1) ld r8,_MSR(r1) #ifdef CONFIG_PPC_BOOK3S /* No MSR:RI on BookE */ andi. r10,r8,MSR_RI beq- .Lunrecov_restore #endif They're all volatile across function calls: http://openpowerfoundation.org/wp-content/uploads/resources/leabi/content/dbdoclet.50655240_68174.html The system_call_exit symbol is actually there for kprobes and cosmetic purposes. The actual syscall return flow starts at .Lsyscall_exit. So I think this would work: diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index db4df061c33a..e19f377a25e0 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -184,6 +184,14 @@ system_call: /* label this so stack traces look sane */ .Lsyscall_exit: std r3,RESULT(r1) + +#ifdef CONFIG_DEBUG_RSEQ + /* Check whether the syscall is issued inside a restartable sequence */ + addi r3,r1,STACK_FRAME_OVERHEAD + bl rseq_syscall + ld r3,RESULT(r1) +#endif + CURRENT_THREAD_INFO(r12, r1) ld r8,_MSR(r1) I'll try and get this series into my test setup at some point, been a bit busy lately :) cheers