Commit c97481ab authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents daa3de23 411c1cf4

arch/arm64/kernel/entry-common.c

+24 −7
Original line number Diff line number Diff line
@@ -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

+0 −8
Original line number Diff line number Diff line
@@ -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

+0 −19
Original line number Diff line number Diff line
@@ -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 */