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-rw-r--r--arch/powerpc/kernel/entry_64.S8
-rw-r--r--arch/powerpc/mm/slb.c6
2 files changed, 6 insertions, 8 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 952eba6701f4..fbbd3f6f0064 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -385,15 +385,15 @@ BEGIN_FTR_SECTION
oris r0,r6,(SLB_ESID_V)@h
ori r0,r0,(SLB_NUM_BOLTED-1)@l
- /* Update the last bolted SLB */
+ /* Update the last bolted SLB. No write barriers are needed
+ * here, provided we only update the current CPU's SLB shadow
+ * buffer.
+ */
ld r9,PACA_SLBSHADOWPTR(r13)
li r12,0
std r12,SLBSHADOW_STACKESID(r9) /* Clear ESID */
- eieio
std r7,SLBSHADOW_STACKVSID(r9) /* Save VSID */
- eieio
std r0,SLBSHADOW_STACKESID(r9) /* Save ESID */
- eieio
slbie r6
slbie r6 /* Workaround POWER5 < DD2.1 issue */
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index ff1811ac6c81..4bee1cfa9dea 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -59,14 +59,12 @@ static inline void slb_shadow_update(unsigned long ea,
{
/*
* Clear the ESID first so the entry is not valid while we are
- * updating it.
+ * updating it. No write barriers are needed here, provided
+ * we only update the current CPU's SLB shadow buffer.
*/
get_slb_shadow()->save_area[entry].esid = 0;
- smp_wmb();
get_slb_shadow()->save_area[entry].vsid = mk_vsid_data(ea, flags);
- smp_wmb();
get_slb_shadow()->save_area[entry].esid = mk_esid_data(ea, entry);
- smp_wmb();
}
static inline void slb_shadow_clear(unsigned long entry)