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

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:

97d935faacde ("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

authored by

Mark Rutland and committed by
Thomas Gleixner 22f66e7e 1f0d117c

+3 -34
+1 -1
include/linux/entry-common.h
··· 321 321 { 322 322 instrumentation_begin(); 323 323 syscall_exit_to_user_mode_work(regs); 324 - local_irq_disable_exit_to_user(); 324 + local_irq_disable(); 325 325 syscall_exit_to_user_mode_prepare(regs); 326 326 instrumentation_end(); 327 327 exit_to_user_mode();
-31
include/linux/irq-entry-common.h
··· 101 101 } 102 102 103 103 /** 104 - * local_irq_enable_exit_to_user - Exit to user variant of local_irq_enable() 105 - * @ti_work: Cached TIF flags gathered with interrupts disabled 106 - * 107 - * Defaults to local_irq_enable(). Can be supplied by architecture specific 108 - * code. 109 - */ 110 - static inline void local_irq_enable_exit_to_user(unsigned long ti_work); 111 - 112 - #ifndef local_irq_enable_exit_to_user 113 - static __always_inline void local_irq_enable_exit_to_user(unsigned long ti_work) 114 - { 115 - local_irq_enable(); 116 - } 117 - #endif 118 - 119 - /** 120 - * local_irq_disable_exit_to_user - Exit to user variant of local_irq_disable() 121 - * 122 - * Defaults to local_irq_disable(). Can be supplied by architecture specific 123 - * code. 124 - */ 125 - static inline void local_irq_disable_exit_to_user(void); 126 - 127 - #ifndef local_irq_disable_exit_to_user 128 - static __always_inline void local_irq_disable_exit_to_user(void) 129 - { 130 - local_irq_disable(); 131 - } 132 - #endif 133 - 134 - /** 135 104 * arch_exit_to_user_mode_work - Architecture specific TIF work for exit 136 105 * to user mode. 137 106 * @regs: Pointer to currents pt_regs
+2 -2
kernel/entry/common.c
··· 47 47 */ 48 48 while (ti_work & EXIT_TO_USER_MODE_WORK_LOOP) { 49 49 50 - local_irq_enable_exit_to_user(ti_work); 50 + local_irq_enable(); 51 51 52 52 if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) { 53 53 if (!rseq_grant_slice_extension(ti_work & TIF_SLICE_EXT_DENY)) ··· 74 74 * might have changed while interrupts and preemption was 75 75 * enabled above. 76 76 */ 77 - local_irq_disable_exit_to_user(); 77 + local_irq_disable(); 78 78 79 79 /* Check if any of the above work has queued a deferred wakeup */ 80 80 tick_nohz_user_enter_prepare();