* [RFC PATCH for 4.18 08/16] powerpc: Add support for restartable sequences
[not found] <20180602124408.8430-1-mathieu.desnoyers@efficios.com>
@ 2018-06-02 12:44 ` Mathieu Desnoyers
2018-06-02 12:44 ` [RFC PATCH for 4.18 09/16] powerpc: Add syscall detection " Mathieu Desnoyers
2018-06-02 12:44 ` [RFC PATCH for 4.18 10/16] powerpc: Wire up restartable sequences system call Mathieu Desnoyers
2 siblings, 0 replies; 7+ messages in thread
From: Mathieu Desnoyers @ 2018-06-02 12:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: 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, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers,
Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
linuxppc-dev
From: Boqun Feng <boqun.feng@gmail.com>
Call the rseq_handle_notify_resume() function on return to userspace if
TIF_NOTIFY_RESUME thread flag is set.
Perform fixup on the pre-signal when a signal is delivered on top of a
restartable sequence critical section.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Peter Zijlstra <peterz@infradead.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/kernel/signal.c | 3 +++
2 files changed, 4 insertions(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c32a181a7cbb..ed21a777e8c6 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -223,6 +223,7 @@ config PPC
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_VIRT_CPU_ACCOUNTING
select HAVE_IRQ_TIME_ACCOUNTING
+ select HAVE_RSEQ
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
select MODULES_USE_ELF_RELA
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index 61db86ecd318..d3bb3aaaf5ac 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -133,6 +133,8 @@ static void do_signal(struct task_struct *tsk)
/* Re-enable the breakpoints for the signal stack */
thread_change_pc(tsk, tsk->thread.regs);
+ rseq_signal_deliver(tsk->thread.regs);
+
if (is32) {
if (ksig.ka.sa.sa_flags & SA_SIGINFO)
ret = handle_rt_signal32(&ksig, oldset, tsk);
@@ -164,6 +166,7 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
+ rseq_handle_notify_resume(regs);
}
user_enter();
--
2.11.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* [RFC PATCH for 4.18 09/16] powerpc: Add syscall detection for restartable sequences
[not found] <20180602124408.8430-1-mathieu.desnoyers@efficios.com>
2018-06-02 12:44 ` [RFC PATCH for 4.18 08/16] powerpc: Add support for restartable sequences Mathieu Desnoyers
@ 2018-06-02 12:44 ` Mathieu Desnoyers
2018-06-05 5:21 ` Michael Ellerman
2018-06-02 12:44 ` [RFC PATCH for 4.18 10/16] powerpc: Wire up restartable sequences system call Mathieu Desnoyers
2 siblings, 1 reply; 7+ messages in thread
From: Mathieu Desnoyers @ 2018-06-02 12:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: 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, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers,
Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
linuxppc-dev
From: Boqun Feng <boqun.feng@gmail.com>
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.
[ Tested on 64-bit powerpc kernel by Mathieu Desnoyers. Still needs to
be tested on 32-bit powerpc kernel. ]
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Peter Zijlstra <peterz@infradead.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/kernel/entry_32.S | 7 +++++++
arch/powerpc/kernel/entry_64.S | 8 ++++++++
2 files changed, 15 insertions(+)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index eb8d01bae8c6..973577f2141c 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -365,6 +365,13 @@ 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 */
+ stw r3,GPR3(r1)
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ bl rseq_syscall
+ lwz r3,GPR3(r1)
+#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 51695608c68b..1c374387656a 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)
--
2.11.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [RFC PATCH for 4.18 09/16] powerpc: Add syscall detection for restartable sequences
2018-06-02 12:44 ` [RFC PATCH for 4.18 09/16] powerpc: Add syscall detection " Mathieu Desnoyers
@ 2018-06-05 5:21 ` Michael Ellerman
2018-06-05 12:50 ` Mathieu Desnoyers
0 siblings, 1 reply; 7+ messages in thread
From: Michael Ellerman @ 2018-06-05 5:21 UTC (permalink / raw)
To: Mathieu Desnoyers, Peter Zijlstra, Paul E . McKenney, Boqun Feng,
Andy Lutomirski, Dave Watson
Cc: 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, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers,
Benjamin Herrenschmidt, Paul Mackerras, linuxppc-dev
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> writes:
> From: Boqun Feng <boqun.feng@gmail.com>
>
> 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.
>
> [ Tested on 64-bit powerpc kernel by Mathieu Desnoyers. Still needs to
> be tested on 32-bit powerpc kernel. ]
>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: Paul Mackerras <paulus@samba.org>
> CC: Michael Ellerman <mpe@ellerman.id.au>
> CC: Peter Zijlstra <peterz@infradead.org>
> CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> CC: linuxppc-dev@lists.ozlabs.org
> ---
> arch/powerpc/kernel/entry_32.S | 7 +++++++
> arch/powerpc/kernel/entry_64.S | 8 ++++++++
> 2 files changed, 15 insertions(+)
I don't _love_ the #ifdefs in here, but they look correct and there's
not really a better option until we rewrite the syscall handler in C.
The rseq selftests passed for me with this applied and enabled. So if
you like here's some tags:
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
cheers
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [RFC PATCH for 4.18 09/16] powerpc: Add syscall detection for restartable sequences
2018-06-05 5:21 ` Michael Ellerman
@ 2018-06-05 12:50 ` Mathieu Desnoyers
0 siblings, 0 replies; 7+ messages in thread
From: Mathieu Desnoyers @ 2018-06-05 12:50 UTC (permalink / raw)
To: Michael Ellerman
Cc: Peter Zijlstra, Paul E. McKenney, Boqun Feng, 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, Will Deacon,
Michael Kerrisk, Joel Fernandes, Benjamin Herrenschmidt,
Paul Mackerras, linuxppc-dev
----- On Jun 5, 2018, at 1:21 AM, Michael Ellerman mpe@ellerman.id.au wrote:
> Mathieu Desnoyers <mathieu.desnoyers@efficios.com> writes:
>> From: Boqun Feng <boqun.feng@gmail.com>
>>
>> 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.
>>
>> [ Tested on 64-bit powerpc kernel by Mathieu Desnoyers. Still needs to
>> be tested on 32-bit powerpc kernel. ]
>>
>> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
>> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
>> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> CC: Paul Mackerras <paulus@samba.org>
>> CC: Michael Ellerman <mpe@ellerman.id.au>
>> CC: Peter Zijlstra <peterz@infradead.org>
>> CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
>> CC: linuxppc-dev@lists.ozlabs.org
>> ---
>> arch/powerpc/kernel/entry_32.S | 7 +++++++
>> arch/powerpc/kernel/entry_64.S | 8 ++++++++
>> 2 files changed, 15 insertions(+)
>
> I don't _love_ the #ifdefs in here, but they look correct and there's
> not really a better option until we rewrite the syscall handler in C.
>
> The rseq selftests passed for me with this applied and enabled. So if
> you like here's some tags:
>
> Tested-by: Michael Ellerman <mpe@ellerman.id.au>
> Acked-by: Michael Ellerman <mpe@ellerman.id.au>
>
Adding you ack to the series.
Thanks!
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* [RFC PATCH for 4.18 10/16] powerpc: Wire up restartable sequences system call
[not found] <20180602124408.8430-1-mathieu.desnoyers@efficios.com>
2018-06-02 12:44 ` [RFC PATCH for 4.18 08/16] powerpc: Add support for restartable sequences Mathieu Desnoyers
2018-06-02 12:44 ` [RFC PATCH for 4.18 09/16] powerpc: Add syscall detection " Mathieu Desnoyers
@ 2018-06-02 12:44 ` Mathieu Desnoyers
2018-06-05 5:18 ` Michael Ellerman
2 siblings, 1 reply; 7+ messages in thread
From: Mathieu Desnoyers @ 2018-06-02 12:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: 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, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers,
Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
linuxppc-dev
From: Boqun Feng <boqun.feng@gmail.com>
Wire up the rseq system call on powerpc.
This provides an ABI improving the speed of a user-space getcpu
operation on powerpc by skipping the getcpu system call on the fast
path, as well as improving the speed of user-space operations on per-cpu
data compared to using load-reservation/store-conditional atomics.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Peter Zijlstra <peterz@infradead.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/include/asm/systbl.h | 1 +
arch/powerpc/include/asm/unistd.h | 2 +-
arch/powerpc/include/uapi/asm/unistd.h | 1 +
3 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h
index d61f9c96d916..45d4d37495fd 100644
--- a/arch/powerpc/include/asm/systbl.h
+++ b/arch/powerpc/include/asm/systbl.h
@@ -392,3 +392,4 @@ SYSCALL(statx)
SYSCALL(pkey_alloc)
SYSCALL(pkey_free)
SYSCALL(pkey_mprotect)
+SYSCALL(rseq)
diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index daf1ba97a00c..1e9708632dce 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -12,7 +12,7 @@
#include <uapi/asm/unistd.h>
-#define NR_syscalls 387
+#define NR_syscalls 388
#define __NR__exit __NR_exit
diff --git a/arch/powerpc/include/uapi/asm/unistd.h b/arch/powerpc/include/uapi/asm/unistd.h
index 389c36fd8299..ac5ba55066dd 100644
--- a/arch/powerpc/include/uapi/asm/unistd.h
+++ b/arch/powerpc/include/uapi/asm/unistd.h
@@ -398,5 +398,6 @@
#define __NR_pkey_alloc 384
#define __NR_pkey_free 385
#define __NR_pkey_mprotect 386
+#define __NR_rseq 387
#endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */
--
2.11.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [RFC PATCH for 4.18 10/16] powerpc: Wire up restartable sequences system call
2018-06-02 12:44 ` [RFC PATCH for 4.18 10/16] powerpc: Wire up restartable sequences system call Mathieu Desnoyers
@ 2018-06-05 5:18 ` Michael Ellerman
2018-06-05 12:51 ` Mathieu Desnoyers
0 siblings, 1 reply; 7+ messages in thread
From: Michael Ellerman @ 2018-06-05 5:18 UTC (permalink / raw)
To: Mathieu Desnoyers, Peter Zijlstra, Paul E . McKenney, Boqun Feng,
Andy Lutomirski, Dave Watson
Cc: 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, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers,
Benjamin Herrenschmidt, Paul Mackerras, linuxppc-dev
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> writes:
> From: Boqun Feng <boqun.feng@gmail.com>
>
> Wire up the rseq system call on powerpc.
>
> This provides an ABI improving the speed of a user-space getcpu
> operation on powerpc by skipping the getcpu system call on the fast
> path, as well as improving the speed of user-space operations on per-cpu
> data compared to using load-reservation/store-conditional atomics.
>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: Paul Mackerras <paulus@samba.org>
> CC: Michael Ellerman <mpe@ellerman.id.au>
> CC: Peter Zijlstra <peterz@infradead.org>
> CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> CC: linuxppc-dev@lists.ozlabs.org
> ---
> arch/powerpc/include/asm/systbl.h | 1 +
> arch/powerpc/include/asm/unistd.h | 2 +-
> arch/powerpc/include/uapi/asm/unistd.h | 1 +
> 3 files changed, 3 insertions(+), 1 deletion(-)
Looks fine to me.
I don't have any other new syscalls in my next, so this should not
conflict with anything for 4.18.
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
cheers
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [RFC PATCH for 4.18 10/16] powerpc: Wire up restartable sequences system call
2018-06-05 5:18 ` Michael Ellerman
@ 2018-06-05 12:51 ` Mathieu Desnoyers
0 siblings, 0 replies; 7+ messages in thread
From: Mathieu Desnoyers @ 2018-06-05 12:51 UTC (permalink / raw)
To: Michael Ellerman
Cc: Peter Zijlstra, Paul E. McKenney, Boqun Feng, 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, Will Deacon,
Michael Kerrisk, Joel Fernandes, Benjamin Herrenschmidt,
Paul Mackerras, linuxppc-dev
----- On Jun 5, 2018, at 1:18 AM, Michael Ellerman mpe@ellerman.id.au wrote:
> Mathieu Desnoyers <mathieu.desnoyers@efficios.com> writes:
>
>> From: Boqun Feng <boqun.feng@gmail.com>
>>
>> Wire up the rseq system call on powerpc.
>>
>> This provides an ABI improving the speed of a user-space getcpu
>> operation on powerpc by skipping the getcpu system call on the fast
>> path, as well as improving the speed of user-space operations on per-cpu
>> data compared to using load-reservation/store-conditional atomics.
>>
>> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
>> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
>> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> CC: Paul Mackerras <paulus@samba.org>
>> CC: Michael Ellerman <mpe@ellerman.id.au>
>> CC: Peter Zijlstra <peterz@infradead.org>
>> CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
>> CC: linuxppc-dev@lists.ozlabs.org
>> ---
>> arch/powerpc/include/asm/systbl.h | 1 +
>> arch/powerpc/include/asm/unistd.h | 2 +-
>> arch/powerpc/include/uapi/asm/unistd.h | 1 +
>> 3 files changed, 3 insertions(+), 1 deletion(-)
>
> Looks fine to me.
>
> I don't have any other new syscalls in my next, so this should not
> conflict with anything for 4.18.
>
> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Added your ack to the series, thanks!
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 7+ messages in thread