[v2 PATCH 1/3] panic: Change nmi_panic from macro to function

From: Hidehiro Kawai
Date: Wed Mar 02 2016 - 05:42:38 EST


Change nmi_panic() macro to a normal function for the portability.
Also, export it for modules.

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@xxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Nicolas Iooss <nicolas.iooss_linux@xxxxxxx>
Cc: Javi Merino <javi.merino@xxxxxxx>
Cc: Gobinda Charan Maji <gobinda.cemk07@xxxxxxxxx>
Cc: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Cc: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
---
include/linux/kernel.h | 22 ++--------------------
kernel/panic.c | 26 ++++++++++++++++++++++++++
2 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index f31638c..daf233f 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -255,7 +255,8 @@ extern long (*panic_blink)(int state);
__printf(1, 2)
void panic(const char *fmt, ...)
__noreturn __cold;
-void nmi_panic_self_stop(struct pt_regs *);
+__printf(2, 3)
+void nmi_panic(struct pt_regs *regs, const char *fmt, ...);
extern void oops_enter(void);
extern void oops_exit(void);
void print_oops_end_marker(void);
@@ -455,25 +456,6 @@ extern atomic_t panic_cpu;
#define PANIC_CPU_INVALID -1

/*
- * A variant of panic() called from NMI context. We return if we've already
- * panicked on this CPU. If another CPU already panicked, loop in
- * nmi_panic_self_stop() which can provide architecture dependent code such
- * as saving register state for crash dump.
- */
-#define nmi_panic(regs, fmt, ...) \
-do { \
- int old_cpu, cpu; \
- \
- cpu = raw_smp_processor_id(); \
- old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); \
- \
- if (old_cpu == PANIC_CPU_INVALID) \
- panic(fmt, ##__VA_ARGS__); \
- else if (old_cpu != cpu) \
- nmi_panic_self_stop(regs); \
-} while (0)
-
-/*
* Only to be used by arch init code. If the user over-wrote the default
* CONFIG_PANIC_TIMEOUT, honor it.
*/
diff --git a/kernel/panic.c b/kernel/panic.c
index d96469d..fb61e54 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -72,6 +72,32 @@ void __weak nmi_panic_self_stop(struct pt_regs *regs)

atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);

+/*
+ * A variant of panic() called from NMI context. We return if we've already
+ * panicked on this CPU. If another CPU already panicked, loop in
+ * nmi_panic_self_stop() which can provide architecture dependent code such
+ * as saving register state for crash dump.
+ */
+void nmi_panic(struct pt_regs *regs, const char *fmt, ...)
+{
+ static char buf[1024]; /* protected by panic_cpu */
+ va_list args;
+ int old_cpu, cpu;
+
+ cpu = raw_smp_processor_id();
+ old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
+
+ if (old_cpu == PANIC_CPU_INVALID) {
+ va_start(args, fmt);
+ vsnprintf(buf, sizeof(buf), fmt, args);
+ va_end(args);
+
+ panic("%s", buf);
+ } else if (old_cpu != cpu)
+ nmi_panic_self_stop(regs);
+}
+EXPORT_SYMBOL(nmi_panic);
+
/**
* panic - halt the system
* @fmt: The text string to print