On 22/12/2025 12:47, 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 split it.
In preparation for moving arm64 over to the generic entry code, split out syscall_exit_to_user_mode_work_prepare() helper from syscall_exit_to_user_mode_work().
No functional changes.
Reviewed-by: Kevin Brodsky kevin.brodsky@arm.com Reviewed-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Jinjie Ruan ruanjinjie@huawei.com
include/linux/entry-common.h | 35 ++++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 13 deletions(-)
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 87efb38b7081..0de0e60630e1 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -121,20 +121,11 @@ static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, l */ 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
- 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().
+/*
- Syscall specific exit to user mode preparation. Runs with interrupts
*/
- enabled.
-static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs) +static __always_inline void syscall_exit_to_user_mode_work_prepare(struct pt_regs *regs) { unsigned long work = READ_ONCE(current_thread_info()->syscall_work); unsigned long nr = syscall_get_nr(current, regs); @@ -155,6 +146,24 @@ 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); +}
+/**
- 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
- 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().
- */
+static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs) +{
- syscall_exit_to_user_mode_work_prepare(regs);
The naming is getting awfully confusing, with the separate introduction of syscall_exit_to_user_mode_prepare().
Having had a closer look, do we really need syscall_exit_to_user_mode_work() as it currently stands? Nothing calls it except the generic syscall_exit_to_user_mode(). Which makes me think: how about moving the two lines below into syscall_exit_to_user_mode() instead of creating a new helper? IOW:
@@ -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(); }
- Kevin
local_irq_disable_exit_to_user(); syscall_exit_to_user_mode_prepare(regs); }