[ARM] 3115/1: small optimizations to exception vector entry code
Patch from Nicolas Pitre
Since we know the value of cpsr on entry, we can replace the bic+orr with
a single eor. Also remove a possible result delay (at least on XScale).
Signed-off-by: Nicolas Pitre <nico@cam.org>
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 be439ca..a511ec5 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -785,7 +785,7 @@
* SP points to a minimal amount of processor-private memory, the address
* of which is copied into r0 for the mode specific abort handler.
*/
- .macro vector_stub, name, correction=0
+ .macro vector_stub, name, mode, correction=0
.align 5
vector_\name:
@@ -805,15 +805,14 @@
@ Prepare for SVC32 mode. IRQs remain disabled.
@
mrs r0, cpsr
- bic r0, r0, #MODE_MASK
- orr r0, r0, #SVC_MODE
+ eor r0, r0, #(\mode ^ SVC_MODE)
msr spsr_cxsf, r0
@
@ the branch table must immediately follow this code
@
- mov r0, sp
and lr, lr, #0x0f
+ mov r0, sp
ldr lr, [pc, lr, lsl #2]
movs pc, lr @ branch to handler in SVC mode
.endm
@@ -823,7 +822,7 @@
/*
* Interrupt dispatcher
*/
- vector_stub irq, 4
+ vector_stub irq, IRQ_MODE, 4
.long __irq_usr @ 0 (USR_26 / USR_32)
.long __irq_invalid @ 1 (FIQ_26 / FIQ_32)
@@ -846,7 +845,7 @@
* Data abort dispatcher
* Enter in ABT mode, spsr = USR CPSR, lr = USR PC
*/
- vector_stub dabt, 8
+ vector_stub dabt, ABT_MODE, 8
.long __dabt_usr @ 0 (USR_26 / USR_32)
.long __dabt_invalid @ 1 (FIQ_26 / FIQ_32)
@@ -869,7 +868,7 @@
* Prefetch abort dispatcher
* Enter in ABT mode, spsr = USR CPSR, lr = USR PC
*/
- vector_stub pabt, 4
+ vector_stub pabt, ABT_MODE, 4
.long __pabt_usr @ 0 (USR_26 / USR_32)
.long __pabt_invalid @ 1 (FIQ_26 / FIQ_32)
@@ -892,7 +891,7 @@
* Undef instr entry dispatcher
* Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
*/
- vector_stub und
+ vector_stub und, UND_MODE
.long __und_usr @ 0 (USR_26 / USR_32)
.long __und_invalid @ 1 (FIQ_26 / FIQ_32)