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Commit f92bac3b authored by Sergey Senozhatsky's avatar Sergey Senozhatsky Committed by Petr Mladek
Browse files

printk: rename nmi.c and exported api 

A preparation patch for printk_safe work. No functional change.
- rename nmi.c to print_safe.c
- add `printk_safe' prefix to some (which used both by printk-safe
  and printk-nmi) of the exported functions.

Link: http://lkml.kernel.org/r/20161227141611.940-3-sergey.senozhatsky@gmail.com


Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Calvin Owens <calvinowens@fb.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
parent bd66a892

include/linux/printk.h

+6 −6
Original line number Diff line number Diff line
@@ -147,17 +147,17 @@ void early_printk(const char *s, ...) { } 
#endif



#ifdef CONFIG_PRINTK_NMI

extern void printk_nmi_init(void);

extern void printk_safe_init(void);

extern void printk_nmi_enter(void);

extern void printk_nmi_exit(void);

extern void printk_nmi_flush(void);

extern void printk_nmi_flush_on_panic(void);

extern void printk_safe_flush(void);

extern void printk_safe_flush_on_panic(void);

#else

static inline void printk_nmi_init(void) { }

static inline void printk_safe_init(void) { }

static inline void printk_nmi_enter(void) { }

static inline void printk_nmi_exit(void) { }

static inline void printk_nmi_flush(void) { }

static inline void printk_nmi_flush_on_panic(void) { }

static inline void printk_safe_flush(void) { }

static inline void printk_safe_flush_on_panic(void) { }

#endif /* PRINTK_NMI */



#ifdef CONFIG_PRINTK

init/Kconfig

+9 −7
Original line number Diff line number Diff line
@@ -875,17 +875,19 @@ config LOG_CPU_MAX_BUF_SHIFT 
		     13 =>   8 KB for each CPU

		     12 =>   4 KB for each CPU



config NMI_LOG_BUF_SHIFT

	int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)"

config PRINTK_SAFE_LOG_BUF_SHIFT

	int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"

	range 10 21

	default 13

	depends on PRINTK_NMI

	depends on PRINTK

	help

	  Select the size of a per-CPU buffer where NMI messages are temporary

	  stored. They are copied to the main log buffer in a safe context

	  to avoid a deadlock. The value defines the size as a power of 2.

	  Select the size of an alternate printk per-CPU buffer where messages

	  printed from usafe contexts are temporary stored. One example would

	  be NMI messages, another one - printk recursion. The messages are

	  copied to the main log buffer in a safe context to avoid a deadlock.

	  The value defines the size as a power of 2.



	  NMI messages are rare and limited. The largest one is when

	  Those messages are rare and limited. The largest one is when

	  a backtrace is printed. It usually fits into 4KB. Select

	  8KB if you want to be on the safe side.

init/main.c

+1 −1
Original line number Diff line number Diff line
@@ -580,7 +580,7 @@ asmlinkage __visible void __init start_kernel(void) 
	timekeeping_init();

	time_init();

	sched_clock_postinit();

	printk_nmi_init();

	printk_safe_init();

	perf_event_init();

	profile_init();

	call_function_init();

kernel/kexec_core.c

+1 −1
Original line number Diff line number Diff line
@@ -916,7 +916,7 @@ void crash_kexec(struct pt_regs *regs) 
	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);

	if (old_cpu == PANIC_CPU_INVALID) {

		/* This is the 1st CPU which comes here, so go ahead. */

		printk_nmi_flush_on_panic();

		printk_safe_flush_on_panic();

		__crash_kexec(regs);



		/*

kernel/panic.c

+2 −2
Original line number Diff line number Diff line
@@ -188,7 +188,7 @@ void panic(const char *fmt, ...) 
	 * Bypass the panic_cpu check and call __crash_kexec directly.

	 */

	if (!_crash_kexec_post_notifiers) {

		printk_nmi_flush_on_panic();

		printk_safe_flush_on_panic();

		__crash_kexec(NULL);



		/*
@@ -213,7 +213,7 @@ void panic(const char *fmt, ...) 
	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);



	/* Call flush even twice. It tries harder with a single online CPU */

	printk_nmi_flush_on_panic();

	printk_safe_flush_on_panic();

	kmsg_dump(KMSG_DUMP_PANIC);



	/*