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 local_irq_disable(); 40 if (!cpumask_test_cpu(cpu, &cpus_in_crash)) 41 crash_save_cpu(regs, cpu); 42 cpumask_set_cpu(cpu, &cpus_in_crash); 43 44 while (!atomic_read(&kexec_ready_to_reboot)) 45 cpu_relax(); 46 relocated_kexec_smp_wait(NULL); 47 /* NOTREACHED */ 48 } 49 50 static void crash_kexec_prepare_cpus(void) 51 { 52 static int cpus_stopped; 53 unsigned int msecs; 54 unsigned int ncpus; 55 56 if (cpus_stopped) 57 return; 58 59 ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ 60 61 smp_call_function(crash_shutdown_secondary, NULL, 0); 62 smp_wmb(); 63 64 /* 65 * The crash CPU sends an IPI and wait for other CPUs to 66 * respond. Delay of at least 10 seconds. 67 */ 68 pr_emerg("Sending IPI to other cpus...\n"); 69 msecs = 10000; 70 while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) { 71 cpu_relax(); 72 mdelay(1); 73 } 74 75 cpus_stopped = 1; 76 } 77 78 /* Override the weak function in kernel/panic.c */ 79 void crash_smp_send_stop(void) 80 { 81 if (_crash_smp_send_stop) 82 _crash_smp_send_stop(); 83 84 crash_kexec_prepare_cpus(); 85 } 86 87 #else /* !defined(CONFIG_SMP) */ 88 static void crash_kexec_prepare_cpus(void) {} 89 #endif /* !defined(CONFIG_SMP) */ 90 91 void default_machine_crash_shutdown(struct pt_regs *regs) 92 { 93 local_irq_disable(); 94 crashing_cpu = smp_processor_id(); 95 crash_save_cpu(regs, crashing_cpu); 96 crash_kexec_prepare_cpus(); 97 cpumask_set_cpu(crashing_cpu, &cpus_in_crash); 98 } 99