Re: [PATCH] s390: add support for TIF_NOTIFY_SIGNAL
From: Sven Schnelle
Date: Tue Nov 03 2020 - 10:11:27 EST
Hi Jens,
Jens Axboe <axboe@xxxxxxxxx> writes:
> On 11/3/20 4:00 AM, Sven Schnelle wrote:
>> Hi Jens,
>>
>> Heiko Carstens <hca () linux ! ibm ! com> writes:
>>
>>> On Thu, Oct 29, 2020 at 10:21:11AM -0600, Jens Axboe wrote:
>>>> Wire up TIF_NOTIFY_SIGNAL handling for s390.
>>>>
>>>> Cc: linux-s390@xxxxxxxxxxxxxxx
>>>> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
>>>> ---
>>>>
>>>> 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@xxxxxxxxx/
>>>>
>>>> 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/s390/include/asm/thread_info.h | 2 ++
>>>> arch/s390/kernel/entry.S | 7 ++++++-
>>>> 2 files changed, 8 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
>>>> index 13a04fcf7762..0045341ade48 100644
>>>> --- a/arch/s390/include/asm/thread_info.h
>>>> +++ b/arch/s390/include/asm/thread_info.h
>>>> @@ -65,6 +65,7 @@ void arch_setup_new_exec(void);
>>>> #define TIF_GUARDED_STORAGE 4 /* load guarded storage control block */
>>>> #define TIF_PATCH_PENDING 5 /* pending live patching update */
>>>> #define TIF_PGSTE 6 /* New mm's will use 4K page tables */
>>>> +#define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */
>>>> #define TIF_ISOLATE_BP 8 /* Run process with isolated BP */
>>>> #define TIF_ISOLATE_BP_GUEST 9 /* Run KVM guests with isolated BP */
>>>>
>>>> @@ -82,6 +83,7 @@ void arch_setup_new_exec(void);
>>>> #define TIF_SYSCALL_TRACEPOINT 27 /* syscall tracepoint instrumentation */
>>>>
>>>> #define _TIF_NOTIFY_RESUME BIT(TIF_NOTIFY_RESUME)
>>>> +#define _TIF_NOTIFY_SIGNAL BIT(TIF_NOTIFY_SIGNAL)
>>>> #define _TIF_SIGPENDING BIT(TIF_SIGPENDING)
>>>> #define _TIF_NEED_RESCHED BIT(TIF_NEED_RESCHED)
>>>> #define _TIF_UPROBE BIT(TIF_UPROBE)
>>>> diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
>>>> index 86235919c2d1..a30d891e8045 100644
>>>> --- a/arch/s390/kernel/entry.S
>>>> +++ b/arch/s390/kernel/entry.S
>>>> @@ -52,7 +52,8 @@ STACK_SIZE = 1 << STACK_SHIFT
>>>> STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
>>>>
>>>> _TIF_WORK = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
>>>> - _TIF_UPROBE | _TIF_GUARDED_STORAGE | _TIF_PATCH_PENDING)
>>>> + _TIF_UPROBE | _TIF_GUARDED_STORAGE | _TIF_PATCH_PENDING | \
>>>> + _TIF_NOTIFY_SIGNAL)
>>>> _TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
>>>> _TIF_SYSCALL_TRACEPOINT)
>>>> _CIF_WORK = (_CIF_ASCE_PRIMARY | _CIF_ASCE_SECONDARY | _CIF_FPU)
>>>> @@ -463,6 +464,8 @@ ENTRY(system_call)
>>>> #endif
>>>> TSTMSK __PT_FLAGS(%r11),_PIF_SYSCALL_RESTART
>>>> jo .Lsysc_syscall_restart
>>>> + TSTMSK __TI_flags(%r12),_TIF_NOTIFY_SIGNAL
>>>> + jo .Lsysc_sigpending
>>>> TSTMSK __TI_flags(%r12),_TIF_SIGPENDING
>>>> jo .Lsysc_sigpending
>>>> TSTMSK __TI_flags(%r12),_TIF_NOTIFY_RESUME
>>>> @@ -857,6 +860,8 @@ ENTRY(io_int_handler)
>>>> #endif
>>>> TSTMSK __TI_flags(%r12),_TIF_SIGPENDING
>>>> jo .Lio_sigpending
>>>> + TSTMSK __TI_flags(%r12),_TIF_NOTIFY_SIGNAL
>>>> + jo .Lio_sigpending
>>>> TSTMSK __TI_flags(%r12),_TIF_NOTIFY_RESUME
>>>> jo .Lio_notify_resume
>>>> TSTMSK __TI_flags(%r12),_TIF_GUARDED_STORAGE
>>>
>>> (full quote so you can make sense of the patch below).
>>>
>>> Please merge the patch below into this one. With that:
>>>
>>> Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
>>>
>>> diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
>>> index a30d891e8045..31f16d903ef3 100644
>>> --- a/arch/s390/kernel/entry.S
>>> +++ b/arch/s390/kernel/entry.S
>>> @@ -464,9 +464,7 @@ ENTRY(system_call)
>>> #endif
>>> TSTMSK __PT_FLAGS(%r11),_PIF_SYSCALL_RESTART
>>> jo .Lsysc_syscall_restart
>>> - TSTMSK __TI_flags(%r12),_TIF_NOTIFY_SIGNAL
>>> - jo .Lsysc_sigpending
>>> - TSTMSK __TI_flags(%r12),_TIF_SIGPENDING
>>> + TSTMSK __TI_flags(%r12),(_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)
>>> jo .Lsysc_sigpending
>>
>> We need to also change the jo to jnz - in combination with tm, jo means
>> 'jump if all tested bits are set' while jnz means 'jump if at least one
>> bit is set'
>
> Ah thanks, good catch. And you also caught the braino in signal.c, here's
> the end result:
>
>
> commit 0eb7d372d5319970bd15f2dbc18264ea576214d4
> Author: Jens Axboe <axboe@xxxxxxxxx>
> Date: Fri Oct 9 15:34:12 2020 -0600
>
> s390: add support for TIF_NOTIFY_SIGNAL
>
> Wire up TIF_NOTIFY_SIGNAL handling for s390.
>
> Cc: linux-s390@xxxxxxxxxxxxxxx
> Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
>
> diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
> index 13a04fcf7762..0045341ade48 100644
> --- a/arch/s390/include/asm/thread_info.h
> +++ b/arch/s390/include/asm/thread_info.h
> @@ -65,6 +65,7 @@ void arch_setup_new_exec(void);
> #define TIF_GUARDED_STORAGE 4 /* load guarded storage control block */
> #define TIF_PATCH_PENDING 5 /* pending live patching update */
> #define TIF_PGSTE 6 /* New mm's will use 4K page tables */
> +#define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */
> #define TIF_ISOLATE_BP 8 /* Run process with isolated BP */
> #define TIF_ISOLATE_BP_GUEST 9 /* Run KVM guests with isolated BP */
>
> @@ -82,6 +83,7 @@ void arch_setup_new_exec(void);
> #define TIF_SYSCALL_TRACEPOINT 27 /* syscall tracepoint instrumentation */
>
> #define _TIF_NOTIFY_RESUME BIT(TIF_NOTIFY_RESUME)
> +#define _TIF_NOTIFY_SIGNAL BIT(TIF_NOTIFY_SIGNAL)
> #define _TIF_SIGPENDING BIT(TIF_SIGPENDING)
> #define _TIF_NEED_RESCHED BIT(TIF_NEED_RESCHED)
> #define _TIF_UPROBE BIT(TIF_UPROBE)
> diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
> index 86235919c2d1..19a89f292290 100644
> --- a/arch/s390/kernel/entry.S
> +++ b/arch/s390/kernel/entry.S
> @@ -52,7 +52,8 @@ STACK_SIZE = 1 << STACK_SHIFT
> STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
>
> _TIF_WORK = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
> - _TIF_UPROBE | _TIF_GUARDED_STORAGE | _TIF_PATCH_PENDING)
> + _TIF_UPROBE | _TIF_GUARDED_STORAGE | _TIF_PATCH_PENDING | \
> + _TIF_NOTIFY_SIGNAL)
> _TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
> _TIF_SYSCALL_TRACEPOINT)
> _CIF_WORK = (_CIF_ASCE_PRIMARY | _CIF_ASCE_SECONDARY | _CIF_FPU)
> @@ -463,8 +464,8 @@ ENTRY(system_call)
> #endif
> TSTMSK __PT_FLAGS(%r11),_PIF_SYSCALL_RESTART
> jo .Lsysc_syscall_restart
> - TSTMSK __TI_flags(%r12),_TIF_SIGPENDING
> - jo .Lsysc_sigpending
> + TSTMSK __TI_flags(%r12),(_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)
> + jnz .Lsysc_sigpending
> TSTMSK __TI_flags(%r12),_TIF_NOTIFY_RESUME
> jo .Lsysc_notify_resume
> TSTMSK __LC_CPU_FLAGS,(_CIF_ASCE_PRIMARY|_CIF_ASCE_SECONDARY)
> @@ -855,8 +856,8 @@ ENTRY(io_int_handler)
> TSTMSK __TI_flags(%r12),_TIF_PATCH_PENDING
> jo .Lio_patch_pending
> #endif
> - TSTMSK __TI_flags(%r12),_TIF_SIGPENDING
> - jo .Lio_sigpending
> + TSTMSK __TI_flags(%r12),(_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)
> + jnz .Lio_sigpending
> TSTMSK __TI_flags(%r12),_TIF_NOTIFY_RESUME
> jo .Lio_notify_resume
> TSTMSK __TI_flags(%r12),_TIF_GUARDED_STORAGE
> diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
> index 9e900a8977bd..b27b6c1f058d 100644
> --- a/arch/s390/kernel/signal.c
> +++ b/arch/s390/kernel/signal.c
> @@ -472,7 +472,7 @@ void do_signal(struct pt_regs *regs)
> current->thread.system_call =
> test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
>
> - if (get_signal(&ksig)) {
> + if (test_thread_flag(TIF_SIGPENDING) && get_signal(&ksig)) {
> /* Whee! Actually deliver the signal. */
> if (current->thread.system_call) {
> regs->int_code = current->thread.system_call;
Looks good, feel free to add my Acked-by.
Thanks
Sven