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Commit 1613cc11 authored by Russell King's avatar Russell King
Browse files

ARM: entry: no need to increase preempt count for IRQ handlers 



irq_enter() and irq_exit() already take care of the preempt_count
handling for interrupts, which increment and decrement the hardirq
bits of the preempt count.  So we can remove the preempt count handing
in our IRQ entry/exit assembly, like x86 did some 9 years ago.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 198a0a92

arch/arm/kernel/entry-armv.S

+4 −23
Original line number Diff line number Diff line
@@ -220,16 +220,12 @@ __irq_svc: 
#ifdef CONFIG_TRACE_IRQFLAGS

	bl	trace_hardirqs_off

#endif

#ifdef CONFIG_PREEMPT

	get_thread_info tsk

	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count

	add	r7, r8, #1			@ increment it

	str	r7, [tsk, #TI_PREEMPT]

#endif



	irq_handler



#ifdef CONFIG_PREEMPT

	str	r8, [tsk, #TI_PREEMPT]		@ restore preempt count

	get_thread_info tsk

	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count

	ldr	r0, [tsk, #TI_FLAGS]		@ get flags

	teq	r8, #0				@ if preempt count != 0

	movne	r0, #0				@ force flags to 0
@@ -432,23 +428,8 @@ __irq_usr: 
	bl	trace_hardirqs_off

#endif



	get_thread_info tsk

#ifdef CONFIG_PREEMPT

	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count

	add	r7, r8, #1			@ increment it

	str	r7, [tsk, #TI_PREEMPT]

#endif



	irq_handler

#ifdef CONFIG_PREEMPT

	ldr	r0, [tsk, #TI_PREEMPT]

	str	r8, [tsk, #TI_PREEMPT]

	teq	r0, r7

 ARM(	strne	r0, [r0, -r0]	)

 THUMB(	movne	r0, #0		)

 THUMB(	strne	r0, [r0]	)

#endif



	get_thread_info tsk

	mov	why, #0

	b	ret_to_user_from_irq

 UNWIND(.fnend		)