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/bootmem.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
crash_shutdown_secondary(void * passed_regs)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, false);
41
42 local_irq_disable();
43 if (!cpumask_test_cpu(cpu, &cpus_in_crash))
44 crash_save_cpu(regs, cpu);
45 cpumask_set_cpu(cpu, &cpus_in_crash);
46
47 while (!atomic_read(&kexec_ready_to_reboot))
48 cpu_relax();
49 relocated_kexec_smp_wait(NULL);
50 /* NOTREACHED */
51 }
52
crash_kexec_prepare_cpus(void)53 static void crash_kexec_prepare_cpus(void)
54 {
55 static int cpus_stopped;
56 unsigned int msecs;
57 unsigned int ncpus;
58
59 if (cpus_stopped)
60 return;
61
62 ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
63
64 smp_call_function(crash_shutdown_secondary, NULL, 0);
65 smp_wmb();
66
67 /*
68 * The crash CPU sends an IPI and wait for other CPUs to
69 * respond. Delay of at least 10 seconds.
70 */
71 pr_emerg("Sending IPI to other cpus...\n");
72 msecs = 10000;
73 while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
74 cpu_relax();
75 mdelay(1);
76 }
77
78 cpus_stopped = 1;
79 }
80
81 /* Override the weak function in kernel/panic.c */
crash_smp_send_stop(void)82 void crash_smp_send_stop(void)
83 {
84 if (_crash_smp_send_stop)
85 _crash_smp_send_stop();
86
87 crash_kexec_prepare_cpus();
88 }
89
90 #else /* !defined(CONFIG_SMP) */
crash_kexec_prepare_cpus(void)91 static void crash_kexec_prepare_cpus(void) {}
92 #endif /* !defined(CONFIG_SMP) */
93
default_machine_crash_shutdown(struct pt_regs * regs)94 void default_machine_crash_shutdown(struct pt_regs *regs)
95 {
96 local_irq_disable();
97 crashing_cpu = smp_processor_id();
98 crash_save_cpu(regs, crashing_cpu);
99 crash_kexec_prepare_cpus();
100 cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
101 }
102