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Fix ARM64-specific rseq regressions, by Mark Rutland.

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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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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
This commit is contained in:
Linus Torvalds 2026-05-17 10:59:32 -07:00
commit c97481ab79
3 changed files with 24 additions and 34 deletions
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31
arch/arm64/kernel/entry-common.c
View File

@ -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)

8
include/linux/irq-entry-common.h
View File

@ -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

19
include/linux/rseq_entry.h
View File

@ -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 */