mips/kernel/crash.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <linux/kernel.h>
0003 #include <linux/smp.h>
0004 #include <linux/reboot.h>
0005 #include <linux/kexec.h>
0006 #include <linux/memblock.h>
0007 #include <linux/crash_dump.h>
0008 #include <linux/delay.h>
0009 #include <linux/irq.h>
0010 #include <linux/types.h>
0011 #include <linux/sched.h>
0012 #include <linux/sched/task_stack.h>
0013
0014 /* This keeps a track of which one is crashing cpu. */
0015 static int crashing_cpu = -1;
0016 static cpumask_t cpus_in_crash = CPU_MASK_NONE;
0017
0018 #ifdef CONFIG_SMP
0019 static void crash_shutdown_secondary(void *passed_regs)
0020 {
0021     struct pt_regs *regs = passed_regs;
0022     int cpu = smp_processor_id();
0023
0024     /*
0025      * If we are passed registers, use those.  Otherwise get the
0026      * regs from the last interrupt, which should be correct, as
0027      * we are in an interrupt.  But if the regs are not there,
0028      * pull them from the top of the stack.  They are probably
0029      * wrong, but we need something to keep from crashing again.
0030      */
0031     if (!regs)
0032         regs = get_irq_regs();
0033     if (!regs)
0034         regs = task_pt_regs(current);
0035
0036     if (!cpu_online(cpu))
0037         return;
0038
0039     /* We won't be sent IPIs any more. */
0040     set_cpu_online(cpu, false);
0041
0042     local_irq_disable();
0043     if (!cpumask_test_cpu(cpu, &cpus_in_crash))
0044         crash_save_cpu(regs, cpu);
0045     cpumask_set_cpu(cpu, &cpus_in_crash);
0046
0047     while (!atomic_read(&kexec_ready_to_reboot))
0048         cpu_relax();
0049
0050     kexec_reboot();
0051
0052     /* NOTREACHED */
0053 }
0054
0055 static void crash_kexec_prepare_cpus(void)
0056 {
0057     static int cpus_stopped;
0058     unsigned int msecs;
0059     unsigned int ncpus;
0060
0061     if (cpus_stopped)
0062         return;
0063
0064     ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
0065
0066     smp_call_function(crash_shutdown_secondary, NULL, 0);
0067     smp_wmb();
0068
0069     /*
0070      * The crash CPU sends an IPI and wait for other CPUs to
0071      * respond. Delay of at least 10 seconds.
0072      */
0073     pr_emerg("Sending IPI to other cpus...\n");
0074     msecs = 10000;
0075     while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
0076         cpu_relax();
0077         mdelay(1);
0078     }
0079
0080     cpus_stopped = 1;
0081 }
0082
0083 /* Override the weak function in kernel/panic.c */
0084 void crash_smp_send_stop(void)
0085 {
0086     if (_crash_smp_send_stop)
0087         _crash_smp_send_stop();
0088
0089     crash_kexec_prepare_cpus();
0090 }
0091
0092 #else /* !defined(CONFIG_SMP)  */
0093 static void crash_kexec_prepare_cpus(void) {}
0094 #endif /* !defined(CONFIG_SMP)  */
0095
0096 void default_machine_crash_shutdown(struct pt_regs *regs)
0097 {
0098     local_irq_disable();
0099     crashing_cpu = smp_processor_id();
0100     crash_save_cpu(regs, crashing_cpu);
0101     crash_kexec_prepare_cpus();
0102     cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
0103 }