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