From: Anton Blanchard <anton@samba.org>
Date: Sat, 10 Jun 2006 15:15:55 +0000 (+1000)
Subject: [POWERPC] system call micro optimisation
X-Git-Tag: v2.6.18-rc1~1081^2~225^2~46
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bd19c8994a828e70b5472f0ce9df5831c6c3db84;p=linux-2.6

[POWERPC] system call micro optimisation

In the syscall path we currently have:

       crclr   so
       mfcr    r9

If we shift the crclr up we can avoid a stall on some CPUs.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
---

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 19ad5c6b18..221062c960 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -57,6 +57,7 @@ system_call_common:
 	beq-	1f
 	ld	r1,PACAKSAVE(r13)
 1:	std	r10,0(r1)
+	crclr	so
 	std	r11,_NIP(r1)
 	std	r12,_MSR(r1)
 	std	r0,GPR0(r1)
@@ -75,7 +76,6 @@ system_call_common:
 	std	r11,GPR11(r1)
 	std	r11,GPR12(r1)
 	std	r9,GPR13(r1)
-	crclr	so
 	mfcr	r9
 	mflr	r10
 	li	r11,0xc01