Merge commit 'v2.6.28-rc7' into tracing/core

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index b00982e0d1ee..383ed6eb0085 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -57,12 +57,18 @@ 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)
         std     r10,GPR1(r1)
         ACCOUNT_CPU_USER_ENTRY(r10, r11)
+        /*
+         * This "crclr so" clears CR0.SO, which is the error indication on
+         * return from this system call.  There must be no cmp instruction
+         * between it and the "mfcr r9" below, otherwise if XER.SO is set,
+         * CR0.SO will get set, causing all system calls to appear to fail.
+         */
+        crclr   so
         std     r2,GPR2(r1)
         std     r3,GPR3(r1)
         std     r4,GPR4(r1)