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entry: Remove local_irq_{enable,disable}_exit_to_user()

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local_irq_enable_exit_to_user() and local_irq_disable_exit_to_user() are
never overridden by architecture code, and are always equivalent to
local_irq_enable() and local_irq_disable().

These functions were added on the assumption that arm64 would override
them to manage 'DAIF' exception masking, as described by Thomas Gleixner
in these threads:

  https://lore.kernel.org/all/20190919150809.340471236@linutronix.de/
  https://lore.kernel.org/all/alpine.DEB.2.21.1910240119090.1852@nanos.tec.linutronix.de/

In practice arm64 did not need to override either. Prior to moving to
the generic irqentry code, arm64's management of DAIF was reworked in
commit:

  97d935faac ("arm64: Unmask Debug + SError in do_notify_resume()")

Since that commit, arm64 only masks interrupts during the 'prepare' step
when returning to user mode, and masks other DAIF exceptions later.
Within arm64_exit_to_user_mode(), the arm64 entry code is as follows:

	local_irq_disable();
	exit_to_user_mode_prepare_legacy(regs);
	local_daif_mask();
	mte_check_tfsr_exit();
	exit_to_user_mode();

Remove the unnecessary local_irq_enable_exit_to_user() and
local_irq_disable_exit_to_user() functions.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260407131650.3813777-3-mark.rutland@arm.com
This commit is contained in:
Mark Rutland
2026-04-07 14:16:42 +01:00
committed by Thomas Gleixner
parent 1f0d117cd6
commit 22f66e7ef4
3 changed files with 3 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/entry-common.h
View File

@@ -321,7 +321,7 @@ static __always_inline void syscall_exit_to_user_mode(struct pt_regs *regs)
{
instrumentation_begin();
syscall_exit_to_user_mode_work(regs);
local_irq_disable_exit_to_user();
local_irq_disable();
syscall_exit_to_user_mode_prepare(regs);
instrumentation_end();
exit_to_user_mode();

31
include/linux/irq-entry-common.h
View File

@@ -100,37 +100,6 @@ static __always_inline void enter_from_user_mode(struct pt_regs *regs)
instrumentation_end();
}
/**
* local_irq_enable_exit_to_user - Exit to user variant of local_irq_enable()
* @ti_work: Cached TIF flags gathered with interrupts disabled
*
* Defaults to local_irq_enable(). Can be supplied by architecture specific
* code.
*/
static inline void local_irq_enable_exit_to_user(unsigned long ti_work);
#ifndef local_irq_enable_exit_to_user
static __always_inline void local_irq_enable_exit_to_user(unsigned long ti_work)
{
local_irq_enable();
}
#endif
/**
* local_irq_disable_exit_to_user - Exit to user variant of local_irq_disable()
*
* Defaults to local_irq_disable(). Can be supplied by architecture specific
* code.
*/
static inline void local_irq_disable_exit_to_user(void);
#ifndef local_irq_disable_exit_to_user
static __always_inline void local_irq_disable_exit_to_user(void)
{
local_irq_disable();
}
#endif
/**
* arch_exit_to_user_mode_work - Architecture specific TIF work for exit
* to user mode.

4
kernel/entry/common.c
View File

@@ -47,7 +47,7 @@ static __always_inline unsigned long __exit_to_user_mode_loop(struct pt_regs *re
*/
while (ti_work & EXIT_TO_USER_MODE_WORK_LOOP) {
local_irq_enable_exit_to_user(ti_work);
local_irq_enable();
if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) {
if (!rseq_grant_slice_extension(ti_work & TIF_SLICE_EXT_DENY))
@@ -74,7 +74,7 @@ static __always_inline unsigned long __exit_to_user_mode_loop(struct pt_regs *re
* might have changed while interrupts and preemption was
* enabled above.
*/
local_irq_disable_exit_to_user();
local_irq_disable();
/* Check if any of the above work has queued a deferred wakeup */
tick_nohz_user_enter_prepare();