[src/trunk]: src/sys/arch/hppa/hppa Add some special NOPs to help qemu.

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

details:   https://anonhg.NetBSD.org/src/rev/9a5dead2c84f
branches:  trunk
changeset: 366085:9a5dead2c84f
user:      skrll <skrll%NetBSD.org@localhost>
date:      Sat May 14 06:07:53 2022 +0000

description:
Add some special NOPs to help qemu.

thanks to Helge Deller for the heads-up.

diffstat:

 sys/arch/hppa/hppa/idle_machdep.c |   9 ++++++---
 sys/arch/hppa/hppa/machdep.c      |  13 +++++++++----
 2 files changed, 15 insertions(+), 7 deletions(-)

diffs (62 lines):

diff -r 968f6dbdf4e3 -r 9a5dead2c84f sys/arch/hppa/hppa/idle_machdep.c
--- a/sys/arch/hppa/hppa/idle_machdep.c Sat May 14 05:35:55 2022 +0000
+++ b/sys/arch/hppa/hppa/idle_machdep.c Sat May 14 06:07:53 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: idle_machdep.c,v 1.3 2019/04/15 20:45:08 skrll Exp $   */
+/*     $NetBSD: idle_machdep.c,v 1.4 2022/05/14 06:07:53 skrll Exp $   */
 
 /*
  * Copyright (c) 2002, 2006, 2007 YAMAMOTO Takashi,
@@ -28,7 +28,7 @@
 
 #include <sys/cdefs.h>
 
-__KERNEL_RCSID(0, "$NetBSD: idle_machdep.c,v 1.3 2019/04/15 20:45:08 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: idle_machdep.c,v 1.4 2022/05/14 06:07:53 skrll Exp $");
 
 #include <sys/param.h>
 #include <sys/cpu.h>
@@ -36,5 +36,8 @@
 void
 cpu_idle(void)
 {
-       /* do nothing */
+        /*
+        * This NOP instruction is used by qemu to detect the idle loop.
+        */
+       __asm volatile("or      %%r10,%%r10,%%r10" ::: "memory");
 }
diff -r 968f6dbdf4e3 -r 9a5dead2c84f sys/arch/hppa/hppa/machdep.c
--- a/sys/arch/hppa/hppa/machdep.c      Sat May 14 05:35:55 2022 +0000
+++ b/sys/arch/hppa/hppa/machdep.c      Sat May 14 06:07:53 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: machdep.c,v 1.16 2020/09/14 16:11:32 skrll Exp $       */
+/*     $NetBSD: machdep.c,v 1.17 2022/05/14 06:07:53 skrll Exp $       */
 
 /*-
  * Copyright (c) 2001, 2002 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.16 2020/09/14 16:11:32 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.17 2022/05/14 06:07:53 skrll Exp $");
 
 #include "opt_cputype.h"
 #include "opt_ddb.h"
@@ -1447,8 +1447,13 @@
                    :: "r" (CMD_RESET), "r" (HPPA_LBCAST + iomod_command));
        }
 
-       for (;;)
-               /* loop while bus reset is coming up */ ;
+       for (;;) {
+               /*
+                * loop while bus reset is coming up.  This NOP instruction
+                * is used by qemu to detect the 'death loop'.
+                */
+               __asm volatile("or %%r31, %%r31, %%r31" ::: "memory");
+       }
        /* NOTREACHED */
 }