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Commit 706fdd9f authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[PATCH] ARM SMP: reallocate main IRQ handler code registers 



By changing r9 -> r8 and r8 to 'tsk' (r9) we are able to remove
one instruction from the preempt path.

Signed-off-by: default avatarRussell King <rmk@arm.linux.org.uk>
parent 187a51ad

arch/arm/kernel/entry-armv.S

+16 −19
Original line number Diff line number Diff line
@@ -144,20 +144,20 @@ __dabt_svc: 
__irq_svc:

	svc_entry irq

#ifdef CONFIG_PREEMPT

	get_thread_info r8

	ldr	r9, [r8, #TI_PREEMPT]		@ get preempt count

	add	r7, r9, #1			@ increment it

	str	r7, [r8, #TI_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

	ldr	r0, [r8, #TI_FLAGS]		@ get flags

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

	tst	r0, #_TIF_NEED_RESCHED

	blne	svc_preempt

preempt_return:

	ldr	r0, [r8, #TI_PREEMPT]		@ read preempt value

	ldr	r0, [tsk, #TI_PREEMPT]		@ read preempt value

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

	teq	r0, r7

	str	r9, [r8, #TI_PREEMPT]		@ restore preempt count

	strne	r0, [r0, -r0]			@ bug()

#endif

	ldr	r0, [sp, #S_PSR]		@ irqs are already disabled
@@ -168,7 +168,7 @@ preempt_return: 


#ifdef CONFIG_PREEMPT

svc_preempt:

	teq	r9, #0				@ was preempt count = 0

	teq	r8, #0				@ was preempt count = 0

	ldreq	r6, .LCirq_stat

	movne	pc, lr				@ no

	ldr	r0, [r6, #4]			@ local_irq_count
@@ -176,9 +176,9 @@ svc_preempt: 
	adds	r0, r0, r1

	movne	pc, lr

	mov	r7, #0				@ preempt_schedule_irq

	str	r7, [r8, #TI_PREEMPT]		@ expects preempt_count == 0

	str	r7, [tsk, #TI_PREEMPT]		@ expects preempt_count == 0

1:	bl	preempt_schedule_irq		@ irq en/disable is done inside

	ldr	r0, [r8, #TI_FLAGS]		@ get new tasks TI_FLAGS

	ldr	r0, [tsk, #TI_FLAGS]		@ get new tasks TI_FLAGS

	tst	r0, #_TIF_NEED_RESCHED

	beq	preempt_return			@ go again

	b	1b
@@ -338,21 +338,18 @@ __dabt_usr: 
__irq_usr:

	usr_entry irq



	get_thread_info tsk

#ifdef CONFIG_PREEMPT

	get_thread_info r8

	ldr	r9, [r8, #TI_PREEMPT]		@ get preempt count

	add	r7, r9, #1			@ increment it

	str	r7, [r8, #TI_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, [r8, #TI_PREEMPT]

	ldr	r0, [tsk, #TI_PREEMPT]

	str	r8, [tsk, #TI_PREEMPT]

	teq	r0, r7

	str	r9, [r8, #TI_PREEMPT]

	strne	r0, [r0, -r0]

	mov	tsk, r8

#else

	get_thread_info tsk

#endif

	mov	why, #0

	b	ret_to_user