[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>
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index d7b2aed..5ad149b 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -88,6 +88,8 @@
very early during boot. 'xmon=on' will just enable the xmon
debugger hooks. 'xmon=off' will disable the debugger hooks
if CONFIG_XMON_DEFAULT is set.
+ xmon will print a backtrace on the very first invocation.
+ 'xmon=nobt' will disable this autobacktrace.
config XMON_DEFAULT
bool "Enable xmon by default"
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index d57930d..465e743 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -441,6 +441,8 @@
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 @@
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;
}
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 179b10c..8adad14 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -137,10 +137,14 @@
static void proccall(void);
void dump_segments(void);
static void symbol_lookup(void);
+static void xmon_show_stack(unsigned long sp, unsigned long lr,
+ unsigned long pc);
static void xmon_print_symbol(unsigned long address, const char *mid,
const char *after);
static const char *getvecname(unsigned long vec);
+int xmon_no_auto_backtrace;
+
extern int print_insn_powerpc(unsigned long, unsigned long, int);
extern void xmon_enter(void);
@@ -736,6 +740,12 @@
last_cmd = NULL;
xmon_regs = excp;
+
+ if (!xmon_no_auto_backtrace) {
+ xmon_no_auto_backtrace = 1;
+ xmon_show_stack(excp->gpr[1], excp->link, excp->nip);
+ }
+
for(;;) {
#ifdef CONFIG_SMP
printf("%x:", smp_processor_id());