[PATCH] ARM: Do not print exception stacktrace in panic

[Sascha Hauer]

panic() prints a stacktrace by default. When being called in a an
exception this will print the stacktrace of the exception stack
which is not useful, so drop it. We are printing the desired
stacktrace anyway before calling panic().

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/cpu/interrupts.c    |  2 +-
 arch/arm/cpu/interrupts_64.c |  2 +-
 common/misc.c                | 29 +++++++++++++++++++++++------
 include/printk.h             |  1 +
 4 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/arch/arm/cpu/interrupts.c b/arch/arm/cpu/interrupts.c
index a1728eb353..5bc790a796 100644
--- a/arch/arm/cpu/interrupts.c
+++ b/arch/arm/cpu/interrupts.c
@@ -68,7 +68,7 @@ static void __noreturn do_exception(struct pt_regs *pt_regs)
 {
 	show_regs(pt_regs);
 
-	panic("");
+	panic_no_stacktrace("");
 }
 
 /**
diff --git a/arch/arm/cpu/interrupts_64.c b/arch/arm/cpu/interrupts_64.c
index f54fdcd3dd..d844915fee 100644
--- a/arch/arm/cpu/interrupts_64.c
+++ b/arch/arm/cpu/interrupts_64.c
@@ -88,7 +88,7 @@ static void __noreturn do_exception(struct pt_regs *pt_regs)
 
 	unwind_backtrace(pt_regs);
 
-	panic("panic: unhandled exception");
+	panic_no_stacktrace("panic: unhandled exception");
 }
 
 /**
diff --git a/common/misc.c b/common/misc.c
index 400c1fb48f..e266f0951e 100644
--- a/common/misc.c
+++ b/common/misc.c
@@ -216,15 +216,13 @@ device_initcall(of_kernel_init);
 
 BAREBOX_MAGICVAR(global.of.kernel.add_machine_compatible, "Additional machine/board compatible");
 
-void __noreturn panic(const char *fmt, ...)
+static void __noreturn do_panic(bool stacktrace, const char *fmt, va_list ap)
 {
-	va_list args;
-	va_start(args, fmt);
-	vprintf(fmt, args);
+	vprintf(fmt, ap);
 	putchar('\n');
-	va_end(args);
 
-	dump_stack();
+	if (stacktrace)
+		dump_stack();
 
 	led_trigger(LED_TRIGGER_PANIC, TRIGGER_ENABLE);
 
@@ -235,4 +233,23 @@ void __noreturn panic(const char *fmt, ...)
 		restart_machine();
 	}
 }
+
+void __noreturn panic(const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	do_panic(true, fmt, args);
+	va_end(args);
+}
 EXPORT_SYMBOL(panic);
+
+void __noreturn panic_no_stacktrace(const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	do_panic(false, fmt, args);
+	va_end(args);
+}
+EXPORT_SYMBOL(panic_no_stacktrace);
diff --git a/include/printk.h b/include/printk.h
index 6f8635fae2..bf9645249d 100644
--- a/include/printk.h
+++ b/include/printk.h
@@ -28,6 +28,7 @@ static inline int printf(const char *fmt, ...)
 #endif
 
 void __attribute__((noreturn)) panic(const char *fmt, ...);
+void __attribute__((noreturn)) panic_no_stacktrace(const char *fmt, ...);
 
 #define printk			printf
 
-- 
2.30.2