1 #include <linux/kernel.h> 2 #include <linux/smp.h> 3 #include <linux/reboot.h> 4 #include <linux/kexec.h> 5 #include <linux/bootmem.h> 6 #include <linux/crash_dump.h> 7 #include <linux/delay.h> 8 #include <linux/irq.h> 9 #include <linux/types.h> 10 #include <linux/sched.h> 11 #include <linux/sched/task_stack.h> 12 13 /* This keeps a track of which one is crashing cpu. */ 14 static int crashing_cpu = -1; 15 static cpumask_t cpus_in_crash = CPU_MASK_NONE; 16 17 #ifdef CONFIG_SMP 18 static void crash_shutdown_secondary(void *passed_regs) 19 { 20 struct pt_regs *regs = passed_regs; 21 int cpu = smp_processor_id(); 22 23 /* 24 * If we are passed registers, use those. Otherwise get the 25 * regs from the last interrupt, which should be correct, as 26 * we are in an interrupt. But if the regs are not there, 27 * pull them from the top of the stack. They are probably 28 * wrong, but we need something to keep from crashing again. 29 */ 30 if (!regs) 31 regs = get_irq_regs(); 32 if (!regs) 33 regs = task_pt_regs(current); 34 35 if (!cpu_online(cpu)) 36 return; 37 38 local_irq_disable(); 39 if (!cpumask_test_cpu(cpu, &cpus_in_crash)) 40 crash_save_cpu(regs, cpu); 41 cpumask_set_cpu(cpu, &cpus_in_crash); 42 43 while (!atomic_read(&kexec_ready_to_reboot)) 44 cpu_relax(); 45 relocated_kexec_smp_wait(NULL); 46 /* NOTREACHED */ 47 } 48 49 static void crash_kexec_prepare_cpus(void) 50 { 51 static int cpus_stopped; 52 unsigned int msecs; 53 unsigned int ncpus; 54 55 if (cpus_stopped) 56 return; 57 58 ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ 59 60 smp_call_function(crash_shutdown_secondary, NULL, 0); 61 smp_wmb(); 62 63 /* 64 * The crash CPU sends an IPI and wait for other CPUs to 65 * respond. Delay of at least 10 seconds. 66 */ 67 pr_emerg("Sending IPI to other cpus...\n"); 68 msecs = 10000; 69 while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) { 70 cpu_relax(); 71 mdelay(1); 72 } 73 74 cpus_stopped = 1; 75 } 76 77 /* Override the weak function in kernel/panic.c */ 78 void crash_smp_send_stop(void) 79 { 80 if (_crash_smp_send_stop) 81 _crash_smp_send_stop(); 82 83 crash_kexec_prepare_cpus(); 84 } 85 86 #else /* !defined(CONFIG_SMP) */ 87 static void crash_kexec_prepare_cpus(void) {} 88 #endif /* !defined(CONFIG_SMP) */ 89 90 void default_machine_crash_shutdown(struct pt_regs *regs) 91 { 92 local_irq_disable(); 93 crashing_cpu = smp_processor_id(); 94 crash_save_cpu(regs, crashing_cpu); 95 crash_kexec_prepare_cpus(); 96 cpumask_set_cpu(crashing_cpu, &cpus_in_crash); 97 } 98