blob: 0fc9803d923bad3f6a2e2b4e39c0332f4ef5440c
| 1 | /* |
| 2 | * NMI backtrace support |
| 3 | * |
| 4 | * Gratuitously copied from arch/x86/kernel/apic/hw_nmi.c by Russell King, |
| 5 | * with the following header: |
| 6 | * |
| 7 | * HW NMI watchdog support |
| 8 | * |
| 9 | * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc. |
| 10 | * |
| 11 | * Arch specific calls to support NMI watchdog |
| 12 | * |
| 13 | * Bits copied from original nmi.c file |
| 14 | */ |
| 15 | #include <linux/cpumask.h> |
| 16 | #include <linux/delay.h> |
| 17 | #include <linux/kprobes.h> |
| 18 | #include <linux/nmi.h> |
| 19 | #include <linux/cpu.h> |
| 20 | |
| 21 | #ifdef arch_trigger_cpumask_backtrace |
| 22 | /* For reliability, we're prepared to waste bits here. */ |
| 23 | static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly; |
| 24 | |
| 25 | /* "in progress" flag of arch_trigger_cpumask_backtrace */ |
| 26 | static unsigned long backtrace_flag; |
| 27 | |
| 28 | /* |
| 29 | * When raise() is called it will be passed a pointer to the |
| 30 | * backtrace_mask. Architectures that call nmi_cpu_backtrace() |
| 31 | * directly from their raise() functions may rely on the mask |
| 32 | * they are passed being updated as a side effect of this call. |
| 33 | */ |
| 34 | void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, |
| 35 | bool exclude_self, |
| 36 | void (*raise)(cpumask_t *mask)) |
| 37 | { |
| 38 | int i, this_cpu = get_cpu(); |
| 39 | |
| 40 | if (test_and_set_bit(0, &backtrace_flag)) { |
| 41 | /* |
| 42 | * If there is already a trigger_all_cpu_backtrace() in progress |
| 43 | * (backtrace_flag == 1), don't output double cpu dump infos. |
| 44 | */ |
| 45 | put_cpu(); |
| 46 | return; |
| 47 | } |
| 48 | |
| 49 | cpumask_copy(to_cpumask(backtrace_mask), mask); |
| 50 | if (exclude_self) |
| 51 | cpumask_clear_cpu(this_cpu, to_cpumask(backtrace_mask)); |
| 52 | |
| 53 | /* |
| 54 | * Don't try to send an NMI to this cpu; it may work on some |
| 55 | * architectures, but on others it may not, and we'll get |
| 56 | * information at least as useful just by doing a dump_stack() here. |
| 57 | * Note that nmi_cpu_backtrace(NULL) will clear the cpu bit. |
| 58 | */ |
| 59 | if (cpumask_test_cpu(this_cpu, to_cpumask(backtrace_mask))) |
| 60 | nmi_cpu_backtrace(NULL); |
| 61 | |
| 62 | if (!cpumask_empty(to_cpumask(backtrace_mask))) { |
| 63 | pr_info("Sending NMI from CPU %d to CPUs %*pbl:\n", |
| 64 | this_cpu, nr_cpumask_bits, to_cpumask(backtrace_mask)); |
| 65 | raise(to_cpumask(backtrace_mask)); |
| 66 | } |
| 67 | |
| 68 | /* Wait for up to 10 seconds for all CPUs to do the backtrace */ |
| 69 | for (i = 0; i < 10 * 1000; i++) { |
| 70 | if (cpumask_empty(to_cpumask(backtrace_mask))) |
| 71 | break; |
| 72 | mdelay(1); |
| 73 | touch_softlockup_watchdog(); |
| 74 | } |
| 75 | |
| 76 | /* |
| 77 | * Force flush any remote buffers that might be stuck in IRQ context |
| 78 | * and therefore could not run their irq_work. |
| 79 | */ |
| 80 | printk_nmi_flush(); |
| 81 | |
| 82 | clear_bit_unlock(0, &backtrace_flag); |
| 83 | put_cpu(); |
| 84 | } |
| 85 | |
| 86 | bool nmi_cpu_backtrace(struct pt_regs *regs) |
| 87 | { |
| 88 | int cpu = smp_processor_id(); |
| 89 | |
| 90 | if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { |
| 91 | if (regs && cpu_in_idle(instruction_pointer(regs))) { |
| 92 | pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n", |
| 93 | cpu, instruction_pointer(regs)); |
| 94 | } else { |
| 95 | pr_warn("NMI backtrace for cpu %d\n", cpu); |
| 96 | /* |
| 97 | * two reasons for not calling show_regs here |
| 98 | * 1. two many logs(100 lines per second) are |
| 99 | * introduced, which makes the wanted stack |
| 100 | * infos missed |
| 101 | * 2. leads to potential external abort on |
| 102 | * non-linefetch issue |
| 103 | */ |
| 104 | #ifndef CONFIG_AMLOGIC_MODIFY |
| 105 | if (regs) |
| 106 | show_regs(regs); |
| 107 | else |
| 108 | #endif |
| 109 | dump_stack(); |
| 110 | } |
| 111 | cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); |
| 112 | return true; |
| 113 | } |
| 114 | |
| 115 | return false; |
| 116 | } |
| 117 | NOKPROBE_SYMBOL(nmi_cpu_backtrace); |
| 118 | #endif |
| 119 |