[src/trunk]: src/sys/arch/ia64/ia64 hopefully fix deadlock issue in cpu_switc...

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

details:   https://anonhg.NetBSD.org/src/rev/d443d7e38910
branches:  trunk
changeset: 447606:d443d7e38910
user:      scole <scole%NetBSD.org@localhost>
date:      Fri Jan 18 18:03:06 2019 +0000

description:
hopefully fix deadlock issue in cpu_switchto.  pointed out by <mrg> (Thanks!)

diffstat:

 sys/arch/ia64/ia64/vm_machdep.c |  16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diffs (40 lines):

diff -r ccdd206fc118 -r d443d7e38910 sys/arch/ia64/ia64/vm_machdep.c
--- a/sys/arch/ia64/ia64/vm_machdep.c   Fri Jan 18 17:49:55 2019 +0000
+++ b/sys/arch/ia64/ia64/vm_machdep.c   Fri Jan 18 18:03:06 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vm_machdep.c,v 1.15 2018/11/14 21:10:59 scole Exp $    */
+/*     $NetBSD: vm_machdep.c,v 1.16 2019/01/18 18:03:06 scole Exp $    */
 
 /*
  * Copyright (c) 2006 The NetBSD Foundation, Inc.
@@ -91,8 +91,9 @@
                KASSERT(oldlwp == l);
                swapctx(oldpcb, newpcb);
        }
-       
-       return (oldlwp);
+
+       /* return oldlwp for the original thread that called cpu_switchto */
+       return ((lwp_t *)reg9);
 }
 
 /*
@@ -189,14 +190,13 @@
                tf->tf_scratch.gr10 = 0;
        }
 
+       pcb2->pcb_special.bspstore = ua2 + UAREA_BSPSTORE_OFFSET + ndirty;
+       pcb2->pcb_special.pfs = 0;
+       pcb2->pcb_special.sp = ua2 + UAREA_SP_OFFSET;
+       pcb2->pcb_special.rp = (unsigned long)FDESC_FUNC(lwp_trampoline);
        tf->tf_scratch.gr2 = (unsigned long)FDESC_FUNC(func);
        tf->tf_scratch.gr3 = (unsigned long)arg;
 
-       pcb2->pcb_special.sp = ua2 + UAREA_SP_OFFSET;
-       pcb2->pcb_special.rp = (unsigned long)FDESC_FUNC(lwp_trampoline);
-       pcb2->pcb_special.bspstore = ua2 + UAREA_BSPSTORE_OFFSET + ndirty;
-       pcb2->pcb_special.pfs = 0;
-
        return;
 }