[PATCH v16 10/18] arm64: ptrace: Extract syscall_exit_to_user_mode_work() helper

In preparation for moving arm64 over to the generic entry code, extract
the core syscall exit tracing logic into a new inline helper,
syscall_exit_to_user_mode_work().

This new helper encapsulates the thread flags retrieval and syscall exit
processing, unifying the exit invocation paths across both the fast-path
bailout block and the slow-path trace_exit fallback in el0_svc_common().
This restructuring significantly streamlines the architecture for
the upcoming transition to the generic entry framework.

No functional changes.

Cc: Mark Rutland <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Ada Couprie Diaz <[email protected]>
Signed-off-by: Jinjie Ruan <[email protected]>
---
 arch/arm64/include/asm/syscall.h | 7 +++++++
 arch/arm64/kernel/syscall.c      | 9 +++------
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index 8205af0be612..72461c22bb5e 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -123,4 +123,11 @@ static inline int syscall_get_arch(struct task_struct *task)
 int syscall_trace_enter(struct pt_regs *regs, unsigned long flags);
 void syscall_exit_work(struct pt_regs *regs, unsigned long flags);
 
+static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs)
+{
+	unsigned long flags = read_thread_flags();
+
+	syscall_exit_work(regs, flags);
+}
+
 #endif	/* __ASM_SYSCALL_H */
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index f6e9aa132b09..6de1fe281d61 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -127,16 +127,13 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
 	 */
 	if (!has_syscall_work(flags) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) {
 		flags = read_thread_flags();
-		if (has_syscall_work(flags) || flags & _TIF_SINGLESTEP) {
-			flags = read_thread_flags();
-			syscall_exit_work(regs, flags);
-		}
+		if (has_syscall_work(flags) || flags & _TIF_SINGLESTEP)
+			syscall_exit_to_user_mode_work(regs);
 		return;
 	}
 
 trace_exit:
-	flags = read_thread_flags();
-	syscall_exit_work(regs, flags);
+	syscall_exit_to_user_mode_work(regs);
 }
 
 void do_el0_svc(struct pt_regs *regs)
-- 
2.34.1