From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Boqun Feng <boqun.feng@gmail.com>, Will Deacon <will.deacon@arm.com>, Peter Zijlstra <peterz@infradead.org>, Andy Lutomirski <luto@amacapital.net>, Dave Watson <davejwatson@fb.com>, linux-kernel <linux-kernel@vger.kernel.org>, linux-api <linux-api@vger.kernel.org>, Paul Turner <pjt@google.com>, Andrew Morton <akpm@linux-foundation.org>, Russell King <linux@arm.linux.org.uk>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>, Andrew Hunter <ahh@google.com>, Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>, Ben Maurer <bmaurer@fb.com>, rostedt <rostedt@goodmis.org>, Josh Triplett <josh@joshtriplett.org>, Linus Torvalds <torvalds@linux-foundation.org>, Catalin Marinas <catalin.marinas@arm.com>, Michael Kerrisk <mtk.manpages@gmail.com>, Joel Fernandes <joelaf@google.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Paul Mackerras <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev <linuxppc-dev@lists.ozlabs.org> Subject: Re: [PATCH 07/14] powerpc: Add support for restartable sequences Date: Wed, 23 May 2018 13:46:35 -0700 [thread overview] Message-ID: <20180523204635.GF3803@linux.vnet.ibm.com> (raw) In-Reply-To: <1928158599.1541.1527106479862.JavaMail.zimbra@efficios.com> On Wed, May 23, 2018 at 04:14:39PM -0400, Mathieu Desnoyers wrote: > ----- 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 ? Hello, Boqun, You can also request access to a ppc64 environment here: http://osuosl.org/services/powerdev/request_hosting/ Thanx, Paul > 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 <boqun.feng@gmail.com> > > --- > > 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 >
WARNING: multiple messages have this Message-ID (diff)
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Boqun Feng <boqun.feng@gmail.com>, Will Deacon <will.deacon@arm.com>, Peter Zijlstra <peterz@infradead.org>, Andy Lutomirski <luto@amacapital.net>, Dave Watson <davejwatson@fb.com>, linux-kernel <linux-kernel@vger.kernel.org>, linux-api <linux-api@vger.kernel.org>, Paul Turner <pjt@google.com>, Andrew Morton <akpm@linux-foundation.org>, Russell King <linux@arm.linux.org.uk>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>, Andrew Hunter <ahh@google.com>, Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>, Ben Maurer <bmaurer@fb.com>, rostedt <rostedt@goodmis.org>, Josh Triplett <josh@joshtriplett.org>, Linus Torvalds <torvalds@linux-foundation.org>, Catalin Marinas <catalin.marinas@ar> Subject: Re: [PATCH 07/14] powerpc: Add support for restartable sequences Date: Wed, 23 May 2018 13:46:35 -0700 [thread overview] Message-ID: <20180523204635.GF3803@linux.vnet.ibm.com> (raw) In-Reply-To: <1928158599.1541.1527106479862.JavaMail.zimbra@efficios.com> On Wed, May 23, 2018 at 04:14:39PM -0400, Mathieu Desnoyers wrote: > ----- 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 ? Hello, Boqun, You can also request access to a ppc64 environment here: http://osuosl.org/services/powerdev/request_hosting/ Thanx, Paul > 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 <boqun.feng@gmail.com> > > --- > > 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 >
next prev parent reply other threads:[~2018-05-23 20:57 UTC|newest] Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-04-30 22:44 [RFC PATCH for 4.18 00/14] Restartable Sequences Mathieu Desnoyers 2018-04-30 22:44 ` [PATCH 01/14] uapi headers: Provide types_32_64.h (v2) Mathieu Desnoyers 2018-04-30 22:44 ` [PATCH 02/14] rseq: Introduce restartable sequences system call (v13) Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-05-16 16:24 ` Peter Zijlstra 2018-05-16 16:24 ` Peter Zijlstra 2018-05-16 20:18 ` Mathieu Desnoyers 2018-05-16 20:18 ` Mathieu Desnoyers 2018-04-30 22:44 ` [PATCH 03/14] arm: Add restartable sequences support Mathieu Desnoyers 2018-05-16 16:18 ` Peter Zijlstra 2018-05-16 16:18 ` Peter Zijlstra 2018-05-16 20:13 ` Mathieu Desnoyers 2018-05-16 20:13 ` Mathieu Desnoyers 2018-05-17 13:32 ` Will Deacon 2018-05-17 13:32 ` Will Deacon 2018-05-17 15:30 ` Mathieu Desnoyers 2018-05-17 15:30 ` Mathieu Desnoyers 2018-05-22 18:19 ` Mathieu Desnoyers 2018-05-22 18:19 ` Mathieu Desnoyers 2018-04-30 22:44 ` [PATCH 04/14] arm: Wire up restartable sequences system call Mathieu Desnoyers 2018-04-30 22:44 ` [PATCH 05/14] x86: Add support for restartable sequences (v2) Mathieu Desnoyers 2018-04-30 22:44 ` [PATCH 06/14] x86: Wire up restartable sequence system call Mathieu Desnoyers 2018-04-30 22:44 ` [PATCH 07/14] powerpc: Add support for restartable sequences Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-05-16 16:18 ` Peter Zijlstra 2018-05-16 16:18 ` Peter Zijlstra 2018-05-16 20:13 ` Mathieu Desnoyers 2018-05-16 20:13 ` Mathieu Desnoyers 2018-05-17 1:19 ` Boqun Feng 2018-05-17 1:19 ` Boqun Feng 2018-05-17 1:19 ` Boqun Feng 2018-05-17 7:43 ` Peter Zijlstra 2018-05-17 7:43 ` Peter Zijlstra 2018-05-17 15:28 ` Mathieu Desnoyers 2018-05-17 15:28 ` Mathieu Desnoyers 2018-05-17 23:50 ` Boqun Feng 2018-05-17 23:50 ` Boqun Feng 2018-05-18 18:17 ` Mathieu Desnoyers 2018-05-18 18:17 ` Mathieu Desnoyers 2018-05-20 14:08 ` Boqun Feng 2018-05-20 14:08 ` Boqun Feng 2018-05-20 14:08 ` Boqun Feng 2018-05-23 20:14 ` Mathieu Desnoyers 2018-05-23 20:14 ` Mathieu Desnoyers 2018-05-23 20:46 ` Paul E. McKenney [this message] 2018-05-23 20:46 ` Paul E. McKenney 2018-05-23 21:29 ` Mathieu Desnoyers 2018-05-23 21:29 ` Mathieu Desnoyers 2018-05-24 1:03 ` Michael Ellerman 2018-05-24 1:03 ` Michael Ellerman 2018-05-28 7:00 ` Mathieu Desnoyers 2018-05-28 7:00 ` Mathieu Desnoyers 2018-05-18 12:38 ` Michael Ellerman 2018-05-18 12:38 ` Michael Ellerman 2018-04-30 22:44 ` [PATCH 08/14] powerpc: Wire up restartable sequences system call Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` [PATCH 09/14] selftests: lib.mk: Introduce OVERRIDE_TARGETS Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` mathieu.desnoyers 2018-04-30 22:44 ` [PATCH 10/14] rseq: selftests: Provide rseq library (v5) Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` mathieu.desnoyers 2018-04-30 22:44 ` [PATCH 11/14] rseq: selftests: Provide basic test Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` mathieu.desnoyers 2018-04-30 22:44 ` [PATCH 12/14] rseq: selftests: Provide basic percpu ops test (v2) Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` mathieu.desnoyers 2018-04-30 22:44 ` [PATCH 13/14] rseq: selftests: Provide parametrized tests (v2) Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` mathieu.desnoyers 2018-04-30 22:44 ` [PATCH 14/14] rseq: selftests: Provide Makefile, scripts, gitignore (v2) Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` Mathieu Desnoyers 2018-04-30 22:44 ` mathieu.desnoyers 2018-05-02 3:53 ` [RFC PATCH for 4.18 00/14] Restartable Sequences Daniel Colascione 2018-05-02 8:43 ` Peter Zijlstra 2018-05-02 16:03 ` Mathieu Desnoyers 2018-05-02 16:03 ` Mathieu Desnoyers 2018-05-02 16:07 ` Daniel Colascione 2018-05-02 16:42 ` Steven Rostedt 2018-05-02 16:55 ` Daniel Colascione 2018-05-03 16:12 ` Mathieu Desnoyers 2018-05-03 16:12 ` Mathieu Desnoyers 2018-05-03 16:22 ` Daniel Colascione 2018-05-03 18:04 ` Mathieu Desnoyers 2018-05-03 18:04 ` Mathieu Desnoyers 2018-05-03 16:48 ` Joel Fernandes 2018-05-03 17:18 ` Daniel Colascione 2018-05-03 17:46 ` Joel Fernandes 2018-05-03 17:46 ` Joel Fernandes 2018-05-04 22:17 ` Ben Maurer 2018-05-04 22:17 ` Ben Maurer 2018-05-02 17:22 ` Peter Zijlstra 2018-05-02 18:27 ` Daniel Colascione 2018-05-02 20:22 ` Peter Zijlstra 2018-05-02 20:37 ` Daniel Colascione 2018-05-03 1:15 ` Steven Rostedt 2018-05-03 8:49 ` Peter Zijlstra 2018-05-06 10:03 ` Thomas Gleixner
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20180523204635.GF3803@linux.vnet.ibm.com \ --to=paulmck@linux.vnet.ibm.com \ --cc=ahh@google.com \ --cc=akpm@linux-foundation.org \ --cc=andi@firstfloor.org \ --cc=benh@kernel.crashing.org \ --cc=bmaurer@fb.com \ --cc=boqun.feng@gmail.com \ --cc=catalin.marinas@arm.com \ --cc=cl@linux.com \ --cc=davejwatson@fb.com \ --cc=hpa@zytor.com \ --cc=joelaf@google.com \ --cc=josh@joshtriplett.org \ --cc=linux-api@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux@arm.linux.org.uk \ --cc=linuxppc-dev@lists.ozlabs.org \ --cc=luto@amacapital.net \ --cc=mathieu.desnoyers@efficios.com \ --cc=mingo@redhat.com \ --cc=mpe@ellerman.id.au \ --cc=mtk.manpages@gmail.com \ --cc=paulus@samba.org \ --cc=peterz@infradead.org \ --cc=pjt@google.com \ --cc=rostedt@goodmis.org \ --cc=tglx@linutronix.de \ --cc=torvalds@linux-foundation.org \ --cc=will.deacon@arm.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.