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>
This commit is contained in:
Sonny Rao 2008-07-12 09:00:26 +10:00 committed by Benjamin Herrenschmidt
parent cd6f37be7f
commit b6f6b98a4e

View file

@ -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)