* [PATCH v4 09/21] powerpc/8xx: Optimize verification in FixupDAR
@ 2014-09-19 8:36 Christophe Leroy
0 siblings, 0 replies; only message in thread
From: Christophe Leroy @ 2014-09-19 8:36 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras
Cc: linux-kernel, linuxppc-dev, Joakim Tjernlund, scottwood
By XORing the upper part of the instruction code, we get a value that can
directly be verified with the second test and we can remove the first test.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
Changes in v2:
- None
Changes in v3:
- None
Changes in v4:
- None
arch/powerpc/kernel/head_8xx.S | 6 ++----
1 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index e5a250c..5037420 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -542,10 +542,8 @@ FixupDAR:/* Entry point for dcbx workaround. */
/* Check if it really is a dcbx instruction. */
/* dcbt and dcbtst does not generate DTLB Misses/Errors,
* no need to include them here */
- srwi r10, r11, 26 /* check if major OP code is 31 */
- cmpwi cr0, r10, 31
- bne- 141f
- rlwinm r10, r11, 0, 21, 30
+ xoris r10, r11, 0x7c00 /* check if major OP code is 31 */
+ rlwinm r10, r10, 0, 21, 5
cmpwi cr0, r10, 2028 /* Is dcbz? */
beq+ 142f
cmpwi cr0, r10, 940 /* Is dcbi? */
--
1.7.1
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