From: Boqun Feng <boqun.feng@gmail.com> To: Mathieu Desnoyers <mathieu.desnoyers@efficios.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>, 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: Sun, 20 May 2018 22:08:11 +0800 [thread overview] Message-ID: <20180520140811.GB1121@tardis> (raw) In-Reply-To: <418003803.516.1526667437396.JavaMail.zimbra@efficios.com> 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. 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
WARNING: multiple messages have this Message-ID (diff)
From: Boqun Feng <boqun.feng@gmail.com> To: Mathieu Desnoyers <mathieu.desnoyers@efficios.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: Sun, 20 May 2018 22:08:11 +0800 [thread overview] Message-ID: <20180520140811.GB1121@tardis> (raw) In-Reply-To: <418003803.516.1526667437396.JavaMail.zimbra@efficios.com> 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. 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
next prev parent reply other threads:[~2018-05-20 14:03 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 [this message] 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 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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