[ARM] Fix kernel mode preemption
Luc Van Oostenryck reported:
The code removed by this patch tested the irq_cpustat_t members
__local_irq_count and __local_bh_count but these fields have
been removed some time ago:
http://git.kernel.org/?p=linux/kernel/git/tglx/history.git;a=commitdiff;h=3ab146c93e039dec99fec8d441a8dd046fe510cc
Fix this oversight.
Acked-by: Bill Gatliff <bgat@billgatliff.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index a46d5b4..65cef87 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -209,14 +209,12 @@
irq_handler
#ifdef CONFIG_PREEMPT
+ str r8, [tsk, #TI_PREEMPT] @ restore preempt count
ldr r0, [tsk, #TI_FLAGS] @ get flags
+ teq r8, #0 @ if preempt count != 0
+ movne r0, #0 @ force flags to 0
tst r0, #_TIF_NEED_RESCHED
blne svc_preempt
-preempt_return:
- ldr r0, [tsk, #TI_PREEMPT] @ read preempt value
- str r8, [tsk, #TI_PREEMPT] @ restore preempt count
- teq r0, r7
- strne r0, [r0, -r0] @ bug()
#endif
ldr r0, [sp, #S_PSR] @ irqs are already disabled
msr spsr_cxsf, r0
@@ -230,19 +228,11 @@
#ifdef CONFIG_PREEMPT
svc_preempt:
- teq r8, #0 @ was preempt count = 0
- ldreq r6, .LCirq_stat
- movne pc, lr @ no
- ldr r0, [r6, #4] @ local_irq_count
- ldr r1, [r6, #8] @ local_bh_count
- adds r0, r0, r1
- movne pc, lr
- mov r7, #0 @ preempt_schedule_irq
- str r7, [tsk, #TI_PREEMPT] @ expects preempt_count == 0
+ mov r8, lr
1: bl preempt_schedule_irq @ irq en/disable is done inside
ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS
tst r0, #_TIF_NEED_RESCHED
- beq preempt_return @ go again
+ moveq pc, r8 @ go again
b 1b
#endif
@@ -326,10 +316,6 @@
#endif
.LCfp:
.word fp_enter
-#ifdef CONFIG_PREEMPT
-.LCirq_stat:
- .word irq_stat
-#endif
/*
* User mode handlers