1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/kernel.h> |
3 | #include <linux/smp.h> |
4 | #include <linux/reboot.h> |
5 | #include <linux/kexec.h> |
6 | #include <linux/memblock.h> |
7 | #include <linux/crash_dump.h> |
8 | #include <linux/delay.h> |
9 | #include <linux/irq.h> |
10 | #include <linux/types.h> |
11 | #include <linux/sched.h> |
12 | #include <linux/sched/task_stack.h> |
13 | |
14 | /* This keeps a track of which one is crashing cpu. */ |
15 | static int crashing_cpu = -1; |
16 | static cpumask_t cpus_in_crash = CPU_MASK_NONE; |
17 | |
18 | #ifdef CONFIG_SMP |
19 | static void crash_shutdown_secondary(void *passed_regs) |
20 | { |
21 | struct pt_regs *regs = passed_regs; |
22 | int cpu = smp_processor_id(); |
23 | |
24 | /* |
25 | * If we are passed registers, use those. Otherwise get the |
26 | * regs from the last interrupt, which should be correct, as |
27 | * we are in an interrupt. But if the regs are not there, |
28 | * pull them from the top of the stack. They are probably |
29 | * wrong, but we need something to keep from crashing again. |
30 | */ |
31 | if (!regs) |
32 | regs = get_irq_regs(); |
33 | if (!regs) |
34 | regs = task_pt_regs(current); |
35 | |
36 | if (!cpu_online(cpu)) |
37 | return; |
38 | |
39 | /* We won't be sent IPIs any more. */ |
40 | set_cpu_online(cpu, online: false); |
41 | |
42 | local_irq_disable(); |
43 | if (!cpumask_test_cpu(cpu, cpumask: &cpus_in_crash)) |
44 | crash_save_cpu(regs, cpu); |
45 | cpumask_set_cpu(cpu, dstp: &cpus_in_crash); |
46 | |
47 | while (!atomic_read(v: &kexec_ready_to_reboot)) |
48 | cpu_relax(); |
49 | |
50 | kexec_reboot(); |
51 | |
52 | /* NOTREACHED */ |
53 | } |
54 | |
55 | static void crash_kexec_prepare_cpus(void) |
56 | { |
57 | static int cpus_stopped; |
58 | unsigned int msecs; |
59 | unsigned int ncpus; |
60 | |
61 | if (cpus_stopped) |
62 | return; |
63 | |
64 | ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ |
65 | |
66 | smp_call_function(func: crash_shutdown_secondary, NULL, wait: 0); |
67 | smp_wmb(); |
68 | |
69 | /* |
70 | * The crash CPU sends an IPI and wait for other CPUs to |
71 | * respond. Delay of at least 10 seconds. |
72 | */ |
73 | pr_emerg("Sending IPI to other cpus...\n" ); |
74 | msecs = 10000; |
75 | while ((cpumask_weight(srcp: &cpus_in_crash) < ncpus) && (--msecs > 0)) { |
76 | cpu_relax(); |
77 | mdelay(1); |
78 | } |
79 | |
80 | cpus_stopped = 1; |
81 | } |
82 | |
83 | /* Override the weak function in kernel/panic.c */ |
84 | void crash_smp_send_stop(void) |
85 | { |
86 | if (_crash_smp_send_stop) |
87 | _crash_smp_send_stop(); |
88 | |
89 | crash_kexec_prepare_cpus(); |
90 | } |
91 | |
92 | #else /* !defined(CONFIG_SMP) */ |
93 | static void crash_kexec_prepare_cpus(void) {} |
94 | #endif /* !defined(CONFIG_SMP) */ |
95 | |
96 | void default_machine_crash_shutdown(struct pt_regs *regs) |
97 | { |
98 | local_irq_disable(); |
99 | crashing_cpu = smp_processor_id(); |
100 | crash_save_cpu(regs, cpu: crashing_cpu); |
101 | crash_kexec_prepare_cpus(); |
102 | cpumask_set_cpu(cpu: crashing_cpu, dstp: &cpus_in_crash); |
103 | } |
104 | |