Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[platform/adaptation/renesas_rcar/renesas_kernel.git] / lib / dump_stack.c
1 /*
2  * Provide a default dump_stack() function for architectures
3  * which don't implement their own.
4  */
5
6 #include <linux/kernel.h>
7 #include <linux/export.h>
8 #include <linux/sched.h>
9 #include <linux/smp.h>
10 #include <linux/atomic.h>
11
12 static void __dump_stack(void)
13 {
14         dump_stack_print_info(KERN_DEFAULT);
15         show_stack(NULL, NULL);
16 }
17
18 /**
19  * dump_stack - dump the current task information and its stack trace
20  *
21  * Architectures can override this implementation by implementing its own.
22  */
23 #ifdef CONFIG_SMP
24 static atomic_t dump_lock = ATOMIC_INIT(-1);
25
26 asmlinkage void dump_stack(void)
27 {
28         int was_locked;
29         int old;
30         int cpu;
31
32         /*
33          * Permit this cpu to perform nested stack dumps while serialising
34          * against other CPUs
35          */
36         preempt_disable();
37
38 retry:
39         cpu = smp_processor_id();
40         old = atomic_cmpxchg(&dump_lock, -1, cpu);
41         if (old == -1) {
42                 was_locked = 0;
43         } else if (old == cpu) {
44                 was_locked = 1;
45         } else {
46                 cpu_relax();
47                 goto retry;
48         }
49
50         __dump_stack();
51
52         if (!was_locked)
53                 atomic_set(&dump_lock, -1);
54
55         preempt_enable();
56 }
57 #else
58 asmlinkage void dump_stack(void)
59 {
60         __dump_stack();
61 }
62 #endif
63 EXPORT_SYMBOL(dump_stack);