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/memblock.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 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 50 kexec_reboot(); 51 52 /* NOTREACHED */ 53 } 54 55 static void crash_kexec_prepare_cpus(void) 56 { 57 static int cpus_stopped; 58 unsigned int msecs; 59 unsigned int ncpus; 60 61 if (cpus_stopped) 62 return; 63 64 ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ 65 66 smp_call_function(crash_shutdown_secondary, NULL, 0); 67 smp_wmb(); 68 69 /* 70 * The crash CPU sends an IPI and wait for other CPUs to 71 * respond. Delay of at least 10 seconds. 72 */ 73 pr_emerg("Sending IPI to other cpus...\n"); 74 msecs = 10000; 75 while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) { 76 cpu_relax(); 77 mdelay(1); 78 } 79 80 cpus_stopped = 1; 81 } 82 83 /* Override the weak function in kernel/panic.c */ 84 void crash_smp_send_stop(void) 85 { 86 if (_crash_smp_send_stop) 87 _crash_smp_send_stop(); 88 89 crash_kexec_prepare_cpus(); 90 } 91 92 #else /* !defined(CONFIG_SMP) */ 93 static void crash_kexec_prepare_cpus(void) {} 94 #endif /* !defined(CONFIG_SMP) */ 95 96 void default_machine_crash_shutdown(struct pt_regs *regs) 97 { 98 local_irq_disable(); 99 crashing_cpu = smp_processor_id(); 100 crash_save_cpu(regs, crashing_cpu); 101 crash_kexec_prepare_cpus(); 102 cpumask_set_cpu(crashing_cpu, &cpus_in_crash); 103 } 104