[PATCH 5/7] ARM: cache-v7: optimise test for Cortex A9 r0pX devices
Russell King
rmk+kernel at arm.linux.org.uk
Fri Apr 3 03:54:37 PDT 2015
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 at arm.linux.org.uk>
---
arch/arm/mm/cache-v7.S | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
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
--
1.8.3.1
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