[PATCH] arm: add support for TIF_NOTIFY_SIGNAL
Jens Axboe
axboe at kernel.dk
Thu Oct 29 13:50:34 EDT 2020
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.
Thanks! I sent out 23 of these today, I'll do some followup next week
if need be :-)
--
Jens Axboe
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