[PATCH] um: add support for TIF_NOTIFY_SIGNAL

[Jens Axboe]

Gentle nudge on this one.

On 10/29/20 10:23 AM, Jens Axboe wrote:
> Wire up TIF_NOTIFY_SIGNAL handling for um.
> 
> Cc: linux-um 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. I'm
> happy carrying this patch if need be, or it can be funelled through the
> arch tree. Let me know.
> 
>  arch/um/include/asm/thread_info.h | 2 ++
>  arch/um/kernel/process.c          | 3 ++-
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/um/include/asm/thread_info.h b/arch/um/include/asm/thread_info.h
> index 4c19ce4c49f1..3b1cb8b3b186 100644
> --- a/arch/um/include/asm/thread_info.h
> +++ b/arch/um/include/asm/thread_info.h
> @@ -57,6 +57,7 @@ static inline struct thread_info *current_thread_info(void)
>  #define TIF_SYSCALL_TRACE	0	/* syscall trace active */
>  #define TIF_SIGPENDING		1	/* signal pending */
>  #define TIF_NEED_RESCHED	2	/* rescheduling necessary */
> +#define TIF_NOTIFY_SIGNAL	3	/* signal notifications exist */
>  #define TIF_RESTART_BLOCK	4
>  #define TIF_MEMDIE		5	/* is terminating due to OOM killer */
>  #define TIF_SYSCALL_AUDIT	6
> @@ -67,6 +68,7 @@ static inline struct thread_info *current_thread_info(void)
>  #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
>  #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
>  #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
> +#define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
>  #define _TIF_MEMDIE		(1 << TIF_MEMDIE)
>  #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
>  #define _TIF_SECCOMP		(1 << TIF_SECCOMP)
> diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
> index 3bed09538dd9..9e19da9e6198 100644
> --- a/arch/um/kernel/process.c
> +++ b/arch/um/kernel/process.c
> @@ -99,7 +99,8 @@ void interrupt_end(void)
>  
>  	if (need_resched())
>  		schedule();
> -	if (test_thread_flag(TIF_SIGPENDING))
> +	if (test_thread_flag(TIF_SIGPENDING) ||
> +	    test_thread_flag(TIF_NOTIFY_SIGNAL))
>  		do_signal(regs);
>  	if (test_thread_flag(TIF_NOTIFY_RESUME))
>  		tracehook_notify_resume(regs);
> 


-- 
Jens Axboe