[src/trunk]: src/sys/arch/powerpc/oea first step to address PR54331:

[macallan <macallan%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/161bda9aced1
branches:  trunk
changeset: 462966:161bda9aced1
user:      macallan <macallan%NetBSD.org@localhost>
date:      Fri Aug 02 05:08:07 2019 +0000

description:
first step to address PR54331:
poll h->hatch_running for a bit instead of blindly relying on a fixed timeout
for secondary CPUs to wake up and get ready

needs more testing, possibly pullup

diffstat:

 sys/arch/powerpc/oea/cpu_subr.c |  15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diffs (36 lines):

diff -r 83f66ee519c1 -r 161bda9aced1 sys/arch/powerpc/oea/cpu_subr.c
--- a/sys/arch/powerpc/oea/cpu_subr.c   Fri Aug 02 05:04:02 2019 +0000
+++ b/sys/arch/powerpc/oea/cpu_subr.c   Fri Aug 02 05:08:07 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu_subr.c,v 1.99 2019/02/06 07:32:50 mrg Exp $        */
+/*     $NetBSD: cpu_subr.c,v 1.100 2019/08/02 05:08:07 macallan Exp $  */
 
 /*-
  * Copyright (c) 2001 Matt Thomas.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu_subr.c,v 1.99 2019/02/06 07:32:50 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu_subr.c,v 1.100 2019/08/02 05:08:07 macallan Exp $");
 
 #include "opt_ppcparam.h"
 #include "opt_ppccache.h"
@@ -1381,6 +1381,17 @@
        __asm volatile ("dcbst 0,%0"::"r"(&h->hatch_running):"memory");
        __asm volatile ("sync; isync");
 #endif
+       int hatch_bail = 0;
+       while ((h->hatch_running < 1) && (hatch_bail < 100000)) {
+               delay(1);
+               hatch_bail++;
+#ifdef CACHE_PROTO_MEI
+               __asm volatile ("dcbi 0,%0"::"r"(&h->hatch_running):"memory");
+               __asm volatile ("sync; isync");
+               __asm volatile ("dcbst 0,%0"::"r"(&h->hatch_running):"memory");
+               __asm volatile ("sync; isync");
+#endif
+       }
        if (h->hatch_running < 1) {
 #ifdef CACHE_PROTO_MEI
                __asm volatile ("dcbi 0,%0"::"r"(&cpu_spinstart_ack):"memory");