[RFC PATCH 2/3] ARM: entry: Remove unneeded need_resched() loop

From: Valentin Schneider
Date: Thu Jan 31 2019 - 13:24:08 EST


Since the enabling and disabling of IRQs within preempt_schedule_irq()
is contained in a need_resched() loop, we don't need the outer arch
code loop.

Signed-off-by: Valentin Schneider <valentin.schneider@xxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Julien Thierry <julien.thierry@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
---
arch/arm/kernel/entry-armv.S | 12 +-----------
1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index e85a3af9ddeb..a7ac22e09bb2 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -220,7 +220,7 @@ __irq_svc:
teq r8, #0 @ if preempt count != 0
movne r0, #0 @ force flags to 0
tst r0, #_TIF_NEED_RESCHED
- blne svc_preempt
+ blne preempt_schedule_irq @ irq en/disable is done inside
#endif

svc_exit r5, irq = 1 @ return from exception
@@ -229,16 +229,6 @@ ENDPROC(__irq_svc)

.ltorg

-#ifdef CONFIG_PREEMPT
-svc_preempt:
- 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
- reteq r8 @ go again
- b 1b
-#endif
-
__und_fault:
@ Correct the PC such that it is pointing at the instruction
@ which caused the fault. If the faulting instruction was ARM
--
2.20.1