[PATCH] arm: add support for TIF_NOTIFY_SIGNAL
Jens Axboe
axboe at kernel.dk
Thu Nov 12 10:51:58 EST 2020
On 11/12/20 8:44 AM, Russell King - ARM Linux admin wrote:
> On Thu, Nov 12, 2020 at 08:42:55AM -0700, Jens Axboe wrote:
>> On 11/12/20 8:32 AM, Russell King - ARM Linux admin wrote:
>>> On Tue, Nov 03, 2020 at 08:11:49AM -0700, Jens Axboe wrote:
>>>> On 10/29/20 11:42 AM, Russell King - ARM Linux admin wrote:
>>>>> On Thu, Oct 29, 2020 at 11:20:07AM -0600, Jens Axboe wrote:
>>>>>> On 10/29/20 11:17 AM, Russell King - ARM Linux admin wrote:
>>>>>>> On Thu, Oct 29, 2020 at 11:15:37AM -0600, Jens Axboe wrote:
>>>>>>>> How about this?
>>>>>>>>
>>>>>>>> commit c03932936d8f99ff7c1c6c7d984e7a457284396c
>>>>>>>> Author: Jens Axboe <axboe at kernel.dk>
>>>>>>>> Date: Fri Oct 9 16:00:49 2020 -0600
>>>>>>>>
>>>>>>>> arm: add support for TIF_NOTIFY_SIGNAL
>>>>>>>>
>>>>>>>> Wire up TIF_NOTIFY_SIGNAL handling for arm.
>>>>>>>>
>>>>>>>> Cc: linux-arm-kernel at lists.infradead.org
>>>>>>>> Signed-off-by: Jens Axboe <axboe at kernel.dk>
>>>>>>>>
>>>>>>>> diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
>>>>>>>> index 536b6b979f63..eb7ce2747eb0 100644
>>>>>>>> --- a/arch/arm/include/asm/thread_info.h
>>>>>>>> +++ b/arch/arm/include/asm/thread_info.h
>>>>>>>> @@ -126,6 +126,8 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
>>>>>>>> * thread information flags:
>>>>>>>> * TIF_USEDFPU - FPU was used by this task this quantum (SMP)
>>>>>>>> * TIF_POLLING_NRFLAG - true if poll_idle() is polling TIF_NEED_RESCHED
>>>>>>>> + *
>>>>>>>> + * Any bit in the range of 0..15 will cause do_work_pending() to be invoked.
>>>>>>>> */
>>>>>>>> #define TIF_SIGPENDING 0 /* signal pending */
>>>>>>>> #define TIF_NEED_RESCHED 1 /* rescheduling necessary */
>>>>>>>> @@ -135,6 +137,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
>>>>>>>> #define TIF_SYSCALL_AUDIT 5 /* syscall auditing active */
>>>>>>>> #define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */
>>>>>>>> #define TIF_SECCOMP 7 /* seccomp syscall filtering active */
>>>>>>>> +#define TIF_NOTIFY_SIGNAL 8 /* signal notifications exist */
>>>>>>>>
>>>>>>>> #define TIF_USING_IWMMXT 17
>>>>>>>> #define TIF_MEMDIE 18 /* is terminating due to OOM killer */
>>>>>>>> @@ -148,6 +151,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
>>>>>>>> #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
>>>>>>>> #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
>>>>>>>> #define _TIF_SECCOMP (1 << TIF_SECCOMP)
>>>>>>>> +#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
>>>>>>>> #define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT)
>>>>>>>>
>>>>>>>> /* Checks for any syscall work in entry-common.S */
>>>>>>>> @@ -158,7 +162,8 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
>>>>>>>> * Change these and you break ASM code in entry-common.S
>>>>>>>> */
>>>>>>>> #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
>>>>>>>> - _TIF_NOTIFY_RESUME | _TIF_UPROBE)
>>>>>>>> + _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
>>>>>>>> + _TIF_NOTIFY_SIGNAL)
>>>>>>>>
>>>>>>>> #endif /* __KERNEL__ */
>>>>>>>> #endif /* __ASM_ARM_THREAD_INFO_H */
>>>>>>>> diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
>>>>>>>> index 271cb8a1eba1..77d16390a524 100644
>>>>>>>> --- a/arch/arm/kernel/entry-common.S
>>>>>>>> +++ b/arch/arm/kernel/entry-common.S
>>>>>>>> @@ -53,7 +53,7 @@ __ret_fast_syscall:
>>>>>>>> cmp r2, #TASK_SIZE
>>>>>>>> blne addr_limit_check_failed
>>>>>>>> ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
>>>>>>>> - tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
>>>>>>>> + movs r1, r1, lsl #16
>>>>>>>> bne fast_work_pending
>>>>>>>>
>>>>>>>>
>>>>>>>> @@ -90,7 +90,7 @@ __ret_fast_syscall:
>>>>>>>> cmp r2, #TASK_SIZE
>>>>>>>> blne addr_limit_check_failed
>>>>>>>> ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
>>>>>>>> - tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
>>>>>>>> + movs r1, r1, lsl #16
>>>>>>>> beq no_work_pending
>>>>>>>> UNWIND(.fnend )
>>>>>>>> ENDPROC(ret_fast_syscall)
>>>>>>>> @@ -131,7 +131,7 @@ ENTRY(ret_to_user_from_irq)
>>>>>>>> cmp r2, #TASK_SIZE
>>>>>>>> blne addr_limit_check_failed
>>>>>>>> ldr r1, [tsk, #TI_FLAGS]
>>>>>>>> - tst r1, #_TIF_WORK_MASK
>>>>>>>> + movs r1, r1, lsl #16
>>>>>>>> bne slow_work_pending
>>>>>>>> no_work_pending:
>>>>>>>> asm_trace_hardirqs_on save = 0
>>>>>>>> diff --git a/arch/arm/kernel/entry-v7m.S b/arch/arm/kernel/entry-v7m.S
>>>>>>>> index de1f20624be1..d0e898608d30 100644
>>>>>>>> --- a/arch/arm/kernel/entry-v7m.S
>>>>>>>> +++ b/arch/arm/kernel/entry-v7m.S
>>>>>>>> @@ -59,7 +59,7 @@ __irq_entry:
>>>>>>>>
>>>>>>>> get_thread_info tsk
>>>>>>>> ldr r2, [tsk, #TI_FLAGS]
>>>>>>>> - tst r2, #_TIF_WORK_MASK
>>>>>>>> + movs r2, r2, lsl #16
>>>>>>>> beq 2f @ no work pending
>>>>>>>> mov r0, #V7M_SCB_ICSR_PENDSVSET
>>>>>>>> str r0, [r1, V7M_SCB_ICSR] @ raise PendSV
>>>>>>>> diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
>>>>>>>> index 585edbfccf6d..9d2e916121be 100644
>>>>>>>> --- a/arch/arm/kernel/signal.c
>>>>>>>> +++ b/arch/arm/kernel/signal.c
>>>>>>>> @@ -655,7 +655,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
>>>>>>>> if (unlikely(!user_mode(regs)))
>>>>>>>> return 0;
>>>>>>>> local_irq_enable();
>>>>>>>> - if (thread_flags & _TIF_SIGPENDING) {
>>>>>>>> + if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
>>>>>>>> int restart = do_signal(regs, syscall);
>>>>>>>> if (unlikely(restart)) {
>>>>>>>> /*
>>>>>>>>
>>>>>>>
>>>>>>> Looks perfect to me, thanks! I assume the pre-requisits for this are
>>>>>>> already in mainline or linux-next?
>>>>>>
>>>>>> Great! Thanks for your expedient attention and help.
>>>>>>
>>>>>> The bits using this are queued in tip for 5.11, so not in mainline yet,
>>>>>> but should be in linux-next tomorrow I guess. But it was done such that
>>>>>> arch patches could be queued up independently, so we didn't have weird
>>>>>> cross dependencies.
>>>>>
>>>>> Okay, I'll wait a few days and see about temporarily dumping it in
>>>>> my for-next branch so it gets a spin through kernelci next week.
>>>>> I'm not anticipating any breakage, so (if I remember) I'll give you
>>>>> a reviewed-by next week once it seems good. As I say, if I remember.
>>>>
>>>> Russell, did you have a chance to run it through the machinery?
>>>
>>> I threw the patch on top of my for-next branch, and let the various
>>> autobuilders chew on it for a few days. I haven't had any reports
>>> back, not even of any breakage through me adding it to my tree.
>>>
>>> I guess that's a positive indication.
>>
>> Good enough to add your acked-by?
>
> I guess.
>
> Acked-by: Russell King <rmk+kernel at armlinux.org.uk>
Thanks Russell, added.
--
Jens Axboe
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