[PATCH] arm: add support for TIF_NOTIFY_SIGNAL
Jens Axboe
axboe at kernel.dk
Thu Oct 29 12:11:07 EDT 2020
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>
---
5.11 has support queued up for TIF_NOTIFY_SIGNAL, see this posting
for details:
https://lore.kernel.org/io-uring/20201026203230.386348-1-axboe@kernel.dk/
As part of that work, I'm adding TIF_NOTIFY_SIGNAL support to all archs,
as that will enable a set of cleanups once all of them support it.
This needs a bit of asm help, immediate doesn't like anything outside
of 1 byte, it seems. Any clues?
arch/arm/include/asm/thread_info.h | 5 ++++-
arch/arm/kernel/entry-common.S | 9 ++++++---
arch/arm/kernel/signal.c | 2 +-
3 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 536b6b979f63..fec16d770180 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -135,6 +135,7 @@ 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 +149,7 @@ 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 +160,8 @@ 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..7485b58673b4 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -53,7 +53,8 @@ __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
+ ldr r2, =#_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+ tst r1, r2
bne fast_work_pending
@@ -90,7 +91,8 @@ __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
+ ldr r2, =#_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+ tst r1, r2
beq no_work_pending
UNWIND(.fnend )
ENDPROC(ret_fast_syscall)
@@ -131,7 +133,8 @@ 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
+ ldr r2, =#_TIF_WORK_MASK
+ tst r1, r2
bne slow_work_pending
no_work_pending:
asm_trace_hardirqs_on save = 0
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)) {
/*
--
2.29.0
--
Jens Axboe
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