From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> To: Michael Ellerman <mpe@ellerman.id.au>, Boqun Feng <boqun.feng@gmail.com> Cc: Will Deacon <will.deacon@arm.com>, Peter Zijlstra <peterz@infradead.org>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, 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>, linuxppc-dev <linuxppc-dev@lists.ozlabs.org> Subject: Re: [PATCH 07/14] powerpc: Add support for restartable sequences Date: Mon, 28 May 2018 03:00:19 -0400 (EDT) [thread overview] Message-ID: <284936908.600.1527490819532.JavaMail.zimbra@efficios.com> (raw) In-Reply-To: <87o9h5sw4e.fsf@concordia.ellerman.id.au> ----- On May 24, 2018, at 3:03 AM, Michael Ellerman mpe@ellerman.id.au wrote: > Mathieu Desnoyers <mathieu.desnoyers@efficios.com> 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 :) Yes, this was needed. I had this in my tree already, but there is still a kernel OOPS when running the rseq selftests on ppc64 with CONFIG_DEBUG_RSEQ=y. My current dev tree is at: https://github.com/compudj/linux-percpu-dev/tree/rseq/dev-local So considering we are at rc7 now, should I plan to removing the powerpc bits for merge window submission, or is there someone planning to spend time on fixing and testing ppc integration before the merge window opens ? Thanks, Mathieu > > cheers -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
WARNING: multiple messages have this Message-ID (diff)
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> To: Michael Ellerman <mpe@ellerman.id.au>, Boqun Feng <boqun.feng@gmail.com> Cc: Will Deacon <will.deacon@arm.com>, Peter Zijlstra <peterz@infradead.org>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, 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 <cata> Subject: Re: [PATCH 07/14] powerpc: Add support for restartable sequences Date: Mon, 28 May 2018 03:00:19 -0400 (EDT) [thread overview] Message-ID: <284936908.600.1527490819532.JavaMail.zimbra@efficios.com> (raw) In-Reply-To: <87o9h5sw4e.fsf@concordia.ellerman.id.au> ----- On May 24, 2018, at 3:03 AM, Michael Ellerman mpe@ellerman.id.au wrote: > Mathieu Desnoyers <mathieu.desnoyers@efficios.com> 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 :) Yes, this was needed. I had this in my tree already, but there is still a kernel OOPS when running the rseq selftests on ppc64 with CONFIG_DEBUG_RSEQ=y. My current dev tree is at: https://github.com/compudj/linux-percpu-dev/tree/rseq/dev-local So considering we are at rc7 now, should I plan to removing the powerpc bits for merge window submission, or is there someone planning to spend time on fixing and testing ppc integration before the merge window opens ? Thanks, Mathieu > > cheers -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
next prev parent reply other threads:[~2018-05-28 7:00 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 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 [this message] 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
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