[POWERPC] print backtrace when entering xmon

xmon does not print a backtrace per default. This is bad on systems with
USB keyboard, the most needed info about the crash is lost.
print a backtrace during the very first xmon entry.

Booting with xmon=nobt disables the autobacktrace functionality.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index d57930d86fa..465e7435efb 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -441,6 +441,8 @@ void __init smp_setup_cpu_maps(void)
 
 int __initdata do_early_xmon;
 #ifdef CONFIG_XMON
+extern int xmon_no_auto_backtrace;
+
 static int __init early_xmon(char *p)
 {
         /* ensure xmon is enabled */
@@ -449,6 +451,8 @@ static int __init early_xmon(char *p)
                         xmon_init(1);
                 if (strncmp(p, "off", 3) == 0)
                         xmon_init(0);
+                if (strncmp(p, "nobt", 4) == 0)
+                        xmon_no_auto_backtrace = 1;
                 if (strncmp(p, "early", 5) != 0)
                         return 0;
         }