Re: [PATCH] s390: add support for TIF_NOTIFY_SIGNAL
From: Jens Axboe
Date: Tue Nov 03 2020 - 09:10:36 EST
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;
--
Jens Axboe