[PATCH v9 03/22] panic: Add vpanic()

[Nam Cao]

vpanic() is useful for implementing runtime verification reactors. Add it.

Signed-off-by: Nam Cao <nam...@linutronix.de>
Reviewed-by: Petr Mladek <pmla...@suse.com>
---
Cc: John Ogness <john.ogn...@linutronix.de>
Cc: Sergey Senozhatsky <senozhat...@chromium.org>
---
 include/linux/panic.h |  3 +++
 kernel/panic.c        | 18 +++++++++++++-----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/include/linux/panic.h b/include/linux/panic.h
index 2494d51707ef..bcca63a02aef 100644
--- a/include/linux/panic.h
+++ b/include/linux/panic.h
@@ -3,6 +3,7 @@
 #define _LINUX_PANIC_H
 
 #include <linux/compiler_attributes.h>
+#include <linux/stdarg.h>
 #include <linux/types.h>
 
 struct pt_regs;
@@ -10,6 +11,8 @@ struct pt_regs;
 extern long (*panic_blink)(int state);
 __printf(1, 2)
 void panic(const char *fmt, ...) __noreturn __cold;
+__printf(1, 0)
+void vpanic(const char *fmt, va_list args) __noreturn __cold;
 void nmi_panic(struct pt_regs *regs, const char *msg);
 void check_panic_on_warn(const char *origin);
 extern void oops_enter(void);
diff --git a/kernel/panic.c b/kernel/panic.c
index a3889f38153d..278eae74bf17 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -277,17 +277,17 @@ static void panic_other_cpus_shutdown(bool crash_kexec)
 }
 
 /**
- *     panic - halt the system
+ *     vpanic - halt the system
  *     @fmt: The text string to print
+ *     @args: Arguments for the format string
  *
  *     Display a message, then perform cleanups.
  *
  *     This function never returns.
  */
-void panic(const char *fmt, ...)
+void vpanic(const char *fmt, va_list args)
 {
        static char buf[1024];
-       va_list args;
        long i, i_next = 0, len;
        int state = 0;
        int old_cpu, this_cpu;
@@ -338,9 +338,7 @@ void panic(const char *fmt, ...)
 
        console_verbose();
        bust_spinlocks(1);
-       va_start(args, fmt);
        len = vscnprintf(buf, sizeof(buf), fmt, args);
-       va_end(args);
 
        if (len && buf[len - 1] == '\n')
                buf[len - 1] = '\0';
@@ -477,7 +475,17 @@ void panic(const char *fmt, ...)
                mdelay(PANIC_TIMER_STEP);
        }
 }
+EXPORT_SYMBOL(vpanic);
 
+/* Identical to vpanic(), except it takes variadic arguments instead of 
va_list */
+void panic(const char *fmt, ...)
+{
+       va_list args;
+
+       va_start(args, fmt);
+       vpanic(fmt, args);
+       va_end(args);
+}
 EXPORT_SYMBOL(panic);
 
 #define TAINT_FLAG(taint, _c_true, _c_false, _module)                  \
-- 
2.39.5