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

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

Signed-off-by: Russell King <rmk@arm.linux.org.uk>
This commit is contained in:
Russell King
2005-05-21 18:15:45 +01:00
committed by Russell King
parent 187a51ad11
commit 706fdd9faa
1 changed files with 16 additions and 19 deletions
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35
arch/arm/kernel/entry-armv.S
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@@ -144,20 +144,20 @@ __dabt_svc:
__irq_svc: __irq_svc:
svc_entry irq svc_entry irq
#ifdef CONFIG_PREEMPT #ifdef CONFIG_PREEMPT
get_thread_info r8 get_thread_info tsk
ldr r9, [r8, #TI_PREEMPT] @ get preempt count ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
add r7, r9, #1 @ increment it add r7, r8, #1 @ increment it
str r7, [r8, #TI_PREEMPT] str r7, [tsk, #TI_PREEMPT]
#endif #endif
irq_handler irq_handler
#ifdef CONFIG_PREEMPT #ifdef CONFIG_PREEMPT
ldr r0, [r8, #TI_FLAGS] @ get flags ldr r0, [tsk, #TI_FLAGS] @ get flags
tst r0, #_TIF_NEED_RESCHED tst r0, #_TIF_NEED_RESCHED
blne svc_preempt blne svc_preempt
preempt_return: 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 teq r0, r7
str r9, [r8, #TI_PREEMPT] @ restore preempt count
strne r0, [r0, -r0] @ bug() strne r0, [r0, -r0] @ bug()
#endif #endif
ldr r0, [sp, #S_PSR] @ irqs are already disabled ldr r0, [sp, #S_PSR] @ irqs are already disabled
@@ -168,7 +168,7 @@ preempt_return:
#ifdef CONFIG_PREEMPT #ifdef CONFIG_PREEMPT
svc_preempt: svc_preempt:
teq r9, #0 @ was preempt count = 0 teq r8, #0 @ was preempt count = 0
ldreq r6, .LCirq_stat ldreq r6, .LCirq_stat
movne pc, lr @ no movne pc, lr @ no
ldr r0, [r6, #4] @ local_irq_count ldr r0, [r6, #4] @ local_irq_count
@@ -176,9 +176,9 @@ svc_preempt:
adds r0, r0, r1 adds r0, r0, r1
movne pc, lr movne pc, lr
mov r7, #0 @ preempt_schedule_irq 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 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 tst r0, #_TIF_NEED_RESCHED
beq preempt_return @ go again beq preempt_return @ go again
b 1b b 1b
@@ -338,21 +338,18 @@ __dabt_usr:
__irq_usr: __irq_usr:
usr_entry irq usr_entry irq
get_thread_info tsk
#ifdef CONFIG_PREEMPT #ifdef CONFIG_PREEMPT
get_thread_info r8 ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
ldr r9, [r8, #TI_PREEMPT] @ get preempt count add r7, r8, #1 @ increment it
add r7, r9, #1 @ increment it str r7, [tsk, #TI_PREEMPT]
str r7, [r8, #TI_PREEMPT]
#endif #endif
irq_handler irq_handler
#ifdef CONFIG_PREEMPT #ifdef CONFIG_PREEMPT
ldr r0, [r8, #TI_PREEMPT] ldr r0, [tsk, #TI_PREEMPT]
str r8, [tsk, #TI_PREEMPT]
teq r0, r7 teq r0, r7
str r9, [r8, #TI_PREEMPT]
strne r0, [r0, -r0] strne r0, [r0, -r0]
mov tsk, r8
#else
get_thread_info tsk
#endif #endif
mov why, #0 mov why, #0
b ret_to_user b ret_to_user