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