Merge tag 'sched-urgent-2026-05-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Ingo Molnar:

 - Fix ARM64-specific rseq regressions (Mark Rutland)

* tag 'sched-urgent-2026-05-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64/entry: Fix arm64-specific rseq brokenness

Author: torvalds

arch/arm64/kernel/entry-common.c

@@ -62,6 +62,13 @@ static void noinstr arm64_exit_to_kernel_mode(struct pt_regs *regs,
 	irqentry_exit_to_kernel_mode_after_preempt(regs, state);
 }
 
+static __always_inline void arm64_syscall_enter_from_user_mode(struct pt_regs *regs)
+{
+	enter_from_user_mode(regs);
+	mte_disable_tco_entry(current);
+	sme_enter_from_user_mode();
+}
+
 /*
  * Handle IRQ/context state management when entering from user mode.
  * Before this function is called it is not safe to call regular kernel code,
@@ -70,20 +77,30 @@ static void noinstr arm64_exit_to_kernel_mode(struct pt_regs *regs,
 static __always_inline void arm64_enter_from_user_mode(struct pt_regs *regs)
 {
 	enter_from_user_mode(regs);
+	rseq_note_user_irq_entry();
 	mte_disable_tco_entry(current);
 	sme_enter_from_user_mode();
 }
 
+static __always_inline void arm64_syscall_exit_to_user_mode(struct pt_regs *regs)
+{
+	local_irq_disable();
+	syscall_exit_to_user_mode_prepare(regs);
+	local_daif_mask();
+	sme_exit_to_user_mode();
+	mte_check_tfsr_exit();
+	exit_to_user_mode();
+}
+
 /*
  * Handle IRQ/context state management when exiting to user mode.
  * After this function returns it is not safe to call regular kernel code,
  * instrumentable code, or any code which may trigger an exception.
  */
-
 static __always_inline void arm64_exit_to_user_mode(struct pt_regs *regs)
 {
 	local_irq_disable();
-	exit_to_user_mode_prepare_legacy(regs);
+	irqentry_exit_to_user_mode_prepare(regs);
 	local_daif_mask();
 	sme_exit_to_user_mode();
 	mte_check_tfsr_exit();
@@ -92,7 +109,7 @@ static __always_inline void arm64_exit_to_user_mode(struct pt_regs *regs)
 
 asmlinkage void noinstr asm_exit_to_user_mode(struct pt_regs *regs)
 {
-	arm64_exit_to_user_mode(regs);
+	arm64_syscall_exit_to_user_mode(regs);
 }
 
 /*
@@ -716,12 +733,12 @@ static void noinstr el0_brk64(struct pt_regs *regs, unsigned long esr)
 
 static void noinstr el0_svc(struct pt_regs *regs)
 {
-	arm64_enter_from_user_mode(regs);
+	arm64_syscall_enter_from_user_mode(regs);
 	cortex_a76_erratum_1463225_svc_handler();
 	fpsimd_syscall_enter();
 	local_daif_restore(DAIF_PROCCTX);
 	do_el0_svc(regs);
-	arm64_exit_to_user_mode(regs);
+	arm64_syscall_exit_to_user_mode(regs);
 	fpsimd_syscall_exit();
 }
 
@@ -868,11 +885,11 @@ static void noinstr el0_cp15(struct pt_regs *regs, unsigned long esr)
 
 static void noinstr el0_svc_compat(struct pt_regs *regs)
 {
-	arm64_enter_from_user_mode(regs);
+	arm64_syscall_enter_from_user_mode(regs);
 	cortex_a76_erratum_1463225_svc_handler();
 	local_daif_restore(DAIF_PROCCTX);
 	do_el0_svc_compat(regs);
-	arm64_exit_to_user_mode(regs);
+	arm64_syscall_exit_to_user_mode(regs);
 }
 
 static void noinstr el0_bkpt32(struct pt_regs *regs, unsigned long esr)

include/linux/irq-entry-common.h

@@ -218,14 +218,6 @@ static __always_inline void __exit_to_user_mode_validate(void)
 	lockdep_sys_exit();
 }
 
-/* Temporary workaround to keep ARM64 alive */
-static __always_inline void exit_to_user_mode_prepare_legacy(struct pt_regs *regs)
-{
-	__exit_to_user_mode_prepare(regs, EXIT_TO_USER_MODE_WORK);
-	rseq_exit_to_user_mode_legacy();
-	__exit_to_user_mode_validate();
-}
-
 /**
  * syscall_exit_to_user_mode_prepare - call exit_to_user_mode_loop() if required
  * @regs:	Pointer to pt_regs on entry stack

include/linux/rseq_entry.h

@@ -749,24 +749,6 @@ static __always_inline void rseq_irqentry_exit_to_user_mode(void)
 	ev->events = 0;
 }
 
-/* Required to keep ARM64 working */
-static __always_inline void rseq_exit_to_user_mode_legacy(void)
-{
-	struct rseq_event *ev = &current->rseq.event;
-
-	rseq_stat_inc(rseq_stats.exit);
-
-	if (static_branch_unlikely(&rseq_debug_enabled))
-		WARN_ON_ONCE(ev->sched_switch);
-
-	/*
-	 * Ensure that event (especially user_irq) is cleared when the
-	 * interrupt did not result in a schedule and therefore the
-	 * rseq processing did not clear it.
-	 */
-	ev->events = 0;
-}
-
 void __rseq_debug_syscall_return(struct pt_regs *regs);
 
 static __always_inline void rseq_debug_syscall_return(struct pt_regs *regs)
@@ -782,7 +764,6 @@ static inline bool rseq_exit_to_user_mode_restart(struct pt_regs *regs, unsigned
 }
 static inline void rseq_syscall_exit_to_user_mode(void) { }
 static inline void rseq_irqentry_exit_to_user_mode(void) { }
-static inline void rseq_exit_to_user_mode_legacy(void) { }
 static inline void rseq_debug_syscall_return(struct pt_regs *regs) { }
 static inline bool rseq_grant_slice_extension(unsigned long ti_work, unsigned long mask) { return false; }
 #endif /* !CONFIG_RSEQ */