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[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>
This commit is contained in:
Nicolas Pitre 2005-11-06 14:42:37 +00:00 committed by Russell King
parent 7240f1f183
commit b7ec479553
1 changed files with 7 additions and 8 deletions
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15
arch/arm/kernel/entry-armv.S
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@ -785,7 +785,7 @@ __kuser_helper_end:
* 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 @@ vector_\name:
@ 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 @@ __stubs_start:
/*
* 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 @@ __stubs_start:
* 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 @@ __stubs_start:
* 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 @@ __stubs_start:
* 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)