[PATCH v11 09/14] entry: Rework syscall_exit_to_user_mode_work() for arch reuse

[Kevin Brodsky]

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 <kevin.brodsky at arm.com>
> Reviewed-by: Thomas Gleixner <tglx at linutronix.de>
> Signed-off-by: Jinjie Ruan <ruanjinjie at huawei.com>
> ---
>  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).

- 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();
>  }