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