From: Sonny Rao Date: Fri, 11 Jul 2008 23:00:26 +0000 (+1000) Subject: powerpc: Don't spin on sync instruction at boot time X-Git-Tag: firefly_0821_release~19653^2~5 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b6f6b98a4e91fcf31db7de54c3aa86252fc6fb5f;p=firefly-linux-kernel-4.4.55.git 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 Signed-off-by: Milton Miller Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index ecced1eb03ae..cc8fb474d520 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)