[PATCH] arm: add support for TIF_NOTIFY_SIGNAL
Russell King - ARM Linux admin
linux at armlinux.org.uk
Thu Oct 29 13:42:36 EDT 2020
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.
--
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