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[5/7] ARM: cache-v7: optimise test for Cortex A9 r0pX devices

Message ID E1YdzFF-0008Cv-OH@rmk-PC.arm.linux.org.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Russell King April 3, 2015, 10:54 a.m. UTC 
Eliminate one unnecessary instruction from this test by pre-shifting
the Cortex A9 ID - we can shift the actual ID in the teq instruction
thereby losing the pX bit of the ID at no cost.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/mm/cache-v7.S | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

Comments

Catalin Marinas April 9, 2015, 5:20 p.m. UTC | #1 
On Fri, Apr 03, 2015 at 11:54:37AM +0100, Russell King wrote:
> Eliminate one unnecessary instruction from this test by pre-shifting
> the Cortex A9 ID - we can shift the actual ID in the teq instruction
> thereby losing the pX bit of the ID at no cost.
> 
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
diff mbox

Patch

diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
index 793d061b4dce..a134d8a13d00 100644
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@@ -97,10 +97,9 @@  ALT_UP(	mov	r3, r0, lsr #26)		@ move LoUU into position
 #ifdef CONFIG_ARM_ERRATA_643719
 ALT_SMP(mrc	p15, 0, r2, c0, c0, 0)		@ read main ID register
 ALT_UP(	ret	lr)				@ LoUU is zero, so nothing to do
-	movw	r1, #:lower16:0x410fc090	@ ID of ARM Cortex A9 r0p?
-	movt	r1, #:upper16:0x410fc090
-	bic	r2, r2, #0x0000000f             @ clear minor revision number
-	teq	r2, r1                          @ test for errata affected core and if so...
+	movw	r1, #:lower16:(0x410fc090 >> 4)	@ ID of ARM Cortex A9 r0p?
+	movt	r1, #:upper16:(0x410fc090 >> 4)
+	teq	r1, r2, lsr #4			@ test for errata affected core and if so...
 	moveq	r3, #1 << 1			@   fix LoUIS value
 	beq	start_flush_levels		@   start flushing cache levels
 #endif