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- // SPDX-License-Identifier: GPL-2.0
- #include <linux/kernel.h>
- #include <linux/smp.h>
- #include <linux/reboot.h>
- #include <linux/kexec.h>
- #include <linux/memblock.h>
- #include <linux/crash_dump.h>
- #include <linux/delay.h>
- #include <linux/irq.h>
- #include <linux/types.h>
- #include <linux/sched.h>
- #include <linux/sched/task_stack.h>
- /* This keeps a track of which one is crashing cpu. */
- static int crashing_cpu = -1;
- static cpumask_t cpus_in_crash = CPU_MASK_NONE;
- #ifdef CONFIG_SMP
- static void crash_shutdown_secondary(void *passed_regs)
- {
- struct pt_regs *regs = passed_regs;
- int cpu = smp_processor_id();
- /*
- * If we are passed registers, use those. Otherwise get the
- * regs from the last interrupt, which should be correct, as
- * we are in an interrupt. But if the regs are not there,
- * pull them from the top of the stack. They are probably
- * wrong, but we need something to keep from crashing again.
- */
- if (!regs)
- regs = get_irq_regs();
- if (!regs)
- regs = task_pt_regs(current);
- if (!cpu_online(cpu))
- return;
- /* We won't be sent IPIs any more. */
- set_cpu_online(cpu, false);
- local_irq_disable();
- if (!cpumask_test_cpu(cpu, &cpus_in_crash))
- crash_save_cpu(regs, cpu);
- cpumask_set_cpu(cpu, &cpus_in_crash);
- while (!atomic_read(&kexec_ready_to_reboot))
- cpu_relax();
- kexec_reboot();
- /* NOTREACHED */
- }
- static void crash_kexec_prepare_cpus(void)
- {
- static int cpus_stopped;
- unsigned int msecs;
- unsigned int ncpus;
- if (cpus_stopped)
- return;
- ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
- smp_call_function(crash_shutdown_secondary, NULL, 0);
- smp_wmb();
- /*
- * The crash CPU sends an IPI and wait for other CPUs to
- * respond. Delay of at least 10 seconds.
- */
- pr_emerg("Sending IPI to other cpus...\n");
- msecs = 10000;
- while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
- cpu_relax();
- mdelay(1);
- }
- cpus_stopped = 1;
- }
- /* Override the weak function in kernel/panic.c */
- void crash_smp_send_stop(void)
- {
- if (_crash_smp_send_stop)
- _crash_smp_send_stop();
- crash_kexec_prepare_cpus();
- }
- #else /* !defined(CONFIG_SMP) */
- static void crash_kexec_prepare_cpus(void) {}
- #endif /* !defined(CONFIG_SMP) */
- void default_machine_crash_shutdown(struct pt_regs *regs)
- {
- local_irq_disable();
- crashing_cpu = smp_processor_id();
- crash_save_cpu(regs, crashing_cpu);
- crash_kexec_prepare_cpus();
- cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
- }
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