Module Name:    src
Committed By:   skrll
Date:           Sat May 14 06:07:53 UTC 2022

Modified Files:
        src/sys/arch/hppa/hppa: idle_machdep.c machdep.c

Log Message:
Add some special NOPs to help qemu.

thanks to Helge Deller for the heads-up.


To generate a diff of this commit:
cvs rdiff -u -r1.3 -r1.4 src/sys/arch/hppa/hppa/idle_machdep.c
cvs rdiff -u -r1.16 -r1.17 src/sys/arch/hppa/hppa/machdep.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/arch/hppa/hppa/idle_machdep.c
diff -u src/sys/arch/hppa/hppa/idle_machdep.c:1.3 src/sys/arch/hppa/hppa/idle_machdep.c:1.4
--- src/sys/arch/hppa/hppa/idle_machdep.c:1.3	Mon Apr 15 20:45:08 2019
+++ src/sys/arch/hppa/hppa/idle_machdep.c	Sat May 14 06:07:53 2022
@@ -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 @@ __KERNEL_RCSID(0, "$NetBSD: idle_machdep
 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");
 }

Index: src/sys/arch/hppa/hppa/machdep.c
diff -u src/sys/arch/hppa/hppa/machdep.c:1.16 src/sys/arch/hppa/hppa/machdep.c:1.17
--- src/sys/arch/hppa/hppa/machdep.c:1.16	Mon Sep 14 16:11:32 2020
+++ src/sys/arch/hppa/hppa/machdep.c	Sat May 14 06:07:53 2022
@@ -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 @@ cpu_reboot(int howto, char *user_boot_st
 		    :: "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 */
 }
 

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