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authorSonny Rao <sonnyrao@us.ibm.com>2008-07-12 09:00:26 +1000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-07-15 12:29:28 +1000
commitb6f6b98a4e91fcf31db7de54c3aa86252fc6fb5f (patch)
treecf28721da06565509e05b7a9b1fa24f69b93f3e6 /arch/powerpc/kernel/head_64.S
parentcd6f37be7fdc9fea407379745350f6630b9d3cdd (diff)
powerpc: Don't spin on sync instruction at boot time
Push the sync below the secondary smp init hold loop and comment its purpose. This should speed up boot by reducing global traffic during the single-threaded portion of boot. Signed-off-by: Sonny Rao <sonnyrao@us.ibm.com> Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/head_64.S')
-rw-r--r--arch/powerpc/kernel/head_64.S3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index ecced1eb03a..cc8fb474d52 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -1198,7 +1198,6 @@ _GLOBAL(generic_secondary_smp_init)
3: HMT_LOW
lbz r23,PACAPROCSTART(r13) /* Test if this processor should */
/* start. */
- sync
#ifndef CONFIG_SMP
b 3b /* Never go on non-SMP */
@@ -1206,6 +1205,8 @@ _GLOBAL(generic_secondary_smp_init)
cmpwi 0,r23,0
beq 3b /* Loop until told to go */
+ sync /* order paca.run and cur_cpu_spec */
+
/* See if we need to call a cpu state restore handler */
LOAD_REG_IMMEDIATE(r23, cur_cpu_spec)
ld r23,0(r23)