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b2c0b2cb RK |
1 | /* |
2 | * NMI backtrace support | |
3 | * | |
4 | * Gratuitously copied from arch/x86/kernel/apic/hw_nmi.c by Russell King, | |
5 | * with the following header: | |
6 | * | |
7 | * HW NMI watchdog support | |
8 | * | |
9 | * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc. | |
10 | * | |
11 | * Arch specific calls to support NMI watchdog | |
12 | * | |
13 | * Bits copied from original nmi.c file | |
14 | */ | |
15 | #include <linux/cpumask.h> | |
16 | #include <linux/delay.h> | |
17 | #include <linux/kprobes.h> | |
18 | #include <linux/nmi.h> | |
b2c0b2cb RK |
19 | |
20 | #ifdef arch_trigger_all_cpu_backtrace | |
21 | /* For reliability, we're prepared to waste bits here. */ | |
22 | static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly; | |
b2c0b2cb RK |
23 | |
24 | /* "in progress" flag of arch_trigger_all_cpu_backtrace */ | |
25 | static unsigned long backtrace_flag; | |
26 | ||
0768330d DT |
27 | /* |
28 | * When raise() is called it will be is passed a pointer to the | |
29 | * backtrace_mask. Architectures that call nmi_cpu_backtrace() | |
30 | * directly from their raise() functions may rely on the mask | |
31 | * they are passed being updated as a side effect of this call. | |
32 | */ | |
b2c0b2cb RK |
33 | void nmi_trigger_all_cpu_backtrace(bool include_self, |
34 | void (*raise)(cpumask_t *mask)) | |
35 | { | |
42a0bb3f | 36 | int i, this_cpu = get_cpu(); |
b2c0b2cb RK |
37 | |
38 | if (test_and_set_bit(0, &backtrace_flag)) { | |
39 | /* | |
40 | * If there is already a trigger_all_cpu_backtrace() in progress | |
41 | * (backtrace_flag == 1), don't output double cpu dump infos. | |
42 | */ | |
43 | put_cpu(); | |
44 | return; | |
45 | } | |
46 | ||
47 | cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask); | |
48 | if (!include_self) | |
49 | cpumask_clear_cpu(this_cpu, to_cpumask(backtrace_mask)); | |
50 | ||
b2c0b2cb RK |
51 | if (!cpumask_empty(to_cpumask(backtrace_mask))) { |
52 | pr_info("Sending NMI to %s CPUs:\n", | |
53 | (include_self ? "all" : "other")); | |
54 | raise(to_cpumask(backtrace_mask)); | |
55 | } | |
56 | ||
57 | /* Wait for up to 10 seconds for all CPUs to do the backtrace */ | |
58 | for (i = 0; i < 10 * 1000; i++) { | |
59 | if (cpumask_empty(to_cpumask(backtrace_mask))) | |
60 | break; | |
61 | mdelay(1); | |
62 | touch_softlockup_watchdog(); | |
63 | } | |
64 | ||
65 | /* | |
42a0bb3f PM |
66 | * Force flush any remote buffers that might be stuck in IRQ context |
67 | * and therefore could not run their irq_work. | |
b2c0b2cb | 68 | */ |
42a0bb3f | 69 | printk_nmi_flush(); |
b2c0b2cb | 70 | |
42a0bb3f | 71 | clear_bit_unlock(0, &backtrace_flag); |
b2c0b2cb RK |
72 | put_cpu(); |
73 | } | |
74 | ||
b2c0b2cb RK |
75 | bool nmi_cpu_backtrace(struct pt_regs *regs) |
76 | { | |
77 | int cpu = smp_processor_id(); | |
78 | ||
79 | if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { | |
b2c0b2cb | 80 | pr_warn("NMI backtrace for cpu %d\n", cpu); |
0768330d DT |
81 | if (regs) |
82 | show_regs(regs); | |
83 | else | |
84 | dump_stack(); | |
b2c0b2cb RK |
85 | cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); |
86 | return true; | |
87 | } | |
88 | ||
89 | return false; | |
90 | } | |
91 | NOKPROBE_SYMBOL(nmi_cpu_backtrace); | |
92 | #endif |