[tip: core/entry] entry: Use syscall number instead of rereading it

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the core/entry branch of tip:

Commit-ID:     8af25d0a2e465f3cb73c47c605fddd1664ee79b2
Gitweb:        https://git.kernel.org/tip/8af25d0a2e465f3cb73c47c605fddd1664ee79b2
Author:        Thomas Gleixner <tglx@xxxxxxxxxx>
AuthorDate:    Tue, 07 Jul 2026 21:06:36 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxx>
CommitterDate: Sun, 12 Jul 2026 12:38:01 +02:00

entry: Use syscall number instead of rereading it

rseq_syscall_enter_work() is invoked before the syscall number can be
modified. So there is no point in rereading it from pt_regs.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxx>
Tested-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@xxxxxxxxx>
Reviewed-by: Radu Rendec <radu@xxxxxxxxxx>
Reviewed-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@xxxxxxxxx>
Reviewed-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxxxxxxxx>
Link: https://patch.msgid.link/20260707190254.181086755@xxxxxxxxxx
---
 include/linux/entry-common.h |  9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index c0f6464..c837352 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -70,9 +70,10 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
 	}
 }
 
-static __always_inline long syscall_trace_enter(struct pt_regs *regs, unsigned long work)
+static __always_inline long syscall_trace_enter(struct pt_regs *regs, unsigned long work,
+						long syscall)
 {
-	long syscall, ret = 0;
+	long ret = 0;
 
 	/*
 	 * Handle Syscall User Dispatch.  This must comes first, since
@@ -90,7 +91,7 @@ static __always_inline long syscall_trace_enter(struct pt_regs *regs, unsigned l
 	 * through hrtimer_interrupt().
 	 */
 	if (work & SYSCALL_WORK_SYSCALL_RSEQ_SLICE)
-		rseq_syscall_enter_work(syscall_get_nr(current, regs));
+		rseq_syscall_enter_work(syscall);
 
 	/* Handle ptrace */
 	if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
@@ -145,7 +146,7 @@ static __always_inline long syscall_enter_from_user_mode_work(struct pt_regs *re
 	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
 
 	if (work & SYSCALL_WORK_ENTER)
-		syscall = syscall_trace_enter(regs, work);
+		syscall = syscall_trace_enter(regs, work, syscall);
 
 	return syscall;
 }