On 2026/1/29 20:06, Kevin Brodsky wrote:
> On 28/01/2026 04:19, Jinjie Ruan wrote:
>> In the generic entry code, the beginning of
>> syscall_exit_to_user_mode_work() can be reused on arm64 so it makes
>> sense to rework it.
>>
>> In preparation for moving arm64 over to the generic entry
>> code, as nothing calls syscall_exit_to_user_mode_work() except for
>> syscall_exit_to_user_mode(), move local_irq_disable_exit_to_user() and
>> syscall_exit_to_user_mode_prepare() out from
>> syscall_exit_to_user_mode_work() to the only one caller.
>>
>> Also update the comment and no functional changes.
>>
>> Reviewed-by: Kevin Brodsky <[email protected]>
>> Reviewed-by: Thomas Gleixner <[email protected]>
>> Signed-off-by: Jinjie Ruan <[email protected]>
>> ---
>> include/linux/entry-common.h | 16 ++++++++--------
>> 1 file changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
>> index e4a8287af822..c4fea642d931 100644
>> --- a/include/linux/entry-common.h
>> +++ b/include/linux/entry-common.h
>> @@ -125,14 +125,14 @@ void syscall_exit_work(struct pt_regs *regs, unsigned
>> long work);
>> * syscall_exit_to_user_mode_work - Handle work before returning to user
>> mode
>> * @regs: Pointer to currents pt_regs
>> *
>> - * Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling
>> + * Same as step 1 of syscall_exit_to_user_mode() but without calling
>> + * local_irq_disable(), syscall_exit_to_user_mode_prepare() and
>> * exit_to_user_mode() to perform the final transition to user mode.
>> *
>> - * Calling convention is the same as for syscall_exit_to_user_mode() and it
>> - * returns with all work handled and interrupts disabled. The caller must
>> - * invoke exit_to_user_mode() before actually switching to user mode to
>> - * make the final state transitions. Interrupts must stay disabled between
>> - * return from this function and the invocation of exit_to_user_mode().
>> + * Calling convention is the same as for syscall_exit_to_user_mode(). The
>> + * caller must invoke local_irq_disable(), __exit_to_user_mode_prepare() and
>
> Shouldn't it be syscall_exit_to_user_mode_prepare() rather than
> __exit_to_user_mode_prepare()? The former has extra calls (e.g. rseq).
Perhaps we can just delete these comments — at present only generic
entry and arm64 use it, and nowhere else needs it; after the refactoring
the comments now seem rather unclear.
>
> - Kevin
>
>> + * exit_to_user_mode() before actually switching to user mode to
>> + * make the final state transitions.
>> */
>> static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs
>> *regs)
>> {
>> @@ -155,8 +155,6 @@ static __always_inline void
>> syscall_exit_to_user_mode_work(struct pt_regs *regs)
>> */
>> if (unlikely(work & SYSCALL_WORK_EXIT))
>> syscall_exit_work(regs, work);
>> - local_irq_disable_exit_to_user();
>> - syscall_exit_to_user_mode_prepare(regs);
>> }
>>
>> /**
>> @@ -192,6 +190,8 @@ static __always_inline void
>> syscall_exit_to_user_mode(struct pt_regs *regs)
>> {
>> instrumentation_begin();
>> syscall_exit_to_user_mode_work(regs);
>> + local_irq_disable_exit_to_user();
>> + syscall_exit_to_user_mode_prepare(regs);
>> instrumentation_end();
>> exit_to_user_mode();
>> }
>
