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