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Date: Tue, 3 Nov 2020 08:12:19 -0700
From: Jens Axboe <axboe@...nel.dk>
To: Sven Schnelle <svens@...ux.ibm.com>
Cc: linux-s390@...r.kernel.org, Heiko Carstens <hca@...ux.ibm.com>,
linux-kernel@...r.kernel.org, peterz@...radead.org,
oleg@...hat.com, tglx@...utronix.de,
Stephen Rothwell <sfr@...b.auug.org.au>,
Linux-Next Mailing List <linux-next@...r.kernel.org>
Subject: Re: [PATCH] s390: add support for TIF_NOTIFY_SIGNAL
On 11/3/20 8:03 AM, Sven Schnelle wrote:
> Hi Jens,
>
> Jens Axboe <axboe@...nel.dk> 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@...r.kernel.org
>>>>> Signed-off-by: Jens Axboe <axboe@...nel.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/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@...ux.ibm.com>
>>>>
>>>> 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@...nel.dk>
>> 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@...r.kernel.org
>> Acked-by: Heiko Carstens <hca@...ux.ibm.com>
>> Signed-off-by: Jens Axboe <axboe@...nel.dk>
>>
>> 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 for your help! Added.
--
Jens Axboe
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