^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * NMI backtrace support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Gratuitously copied from arch/x86/kernel/apic/hw_nmi.c by Russell King,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * with the following header:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * HW NMI watchdog support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * Arch specific calls to support NMI watchdog
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) * Bits copied from original nmi.c file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/cpumask.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <linux/delay.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <linux/kprobes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include <linux/nmi.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #include <linux/cpu.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #include <linux/sched/debug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #ifdef arch_trigger_cpumask_backtrace
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) /* For reliability, we're prepared to waste bits here. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) /* "in progress" flag of arch_trigger_cpumask_backtrace */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) static unsigned long backtrace_flag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * When raise() is called it will be passed a pointer to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) * backtrace_mask. Architectures that call nmi_cpu_backtrace()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * directly from their raise() functions may rely on the mask
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * they are passed being updated as a side effect of this call.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) void nmi_trigger_cpumask_backtrace(const cpumask_t *mask,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) bool exclude_self,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) void (*raise)(cpumask_t *mask))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) int i, this_cpu = get_cpu();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) if (test_and_set_bit(0, &backtrace_flag)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * If there is already a trigger_all_cpu_backtrace() in progress
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) * (backtrace_flag == 1), don't output double cpu dump infos.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) put_cpu();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) cpumask_copy(to_cpumask(backtrace_mask), mask);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) if (exclude_self)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) cpumask_clear_cpu(this_cpu, to_cpumask(backtrace_mask));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) * Don't try to send an NMI to this cpu; it may work on some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) * architectures, but on others it may not, and we'll get
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * information at least as useful just by doing a dump_stack() here.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) * Note that nmi_cpu_backtrace(NULL) will clear the cpu bit.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) if (cpumask_test_cpu(this_cpu, to_cpumask(backtrace_mask)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) nmi_cpu_backtrace(NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) if (!cpumask_empty(to_cpumask(backtrace_mask))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) pr_info("Sending NMI from CPU %d to CPUs %*pbl:\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) this_cpu, nr_cpumask_bits, to_cpumask(backtrace_mask));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) raise(to_cpumask(backtrace_mask));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) /* Wait for up to 10 seconds for all CPUs to do the backtrace */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) for (i = 0; i < 10 * 1000; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) if (cpumask_empty(to_cpumask(backtrace_mask)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) mdelay(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) touch_softlockup_watchdog();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) * Force flush any remote buffers that might be stuck in IRQ context
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) * and therefore could not run their irq_work.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) printk_safe_flush();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) clear_bit_unlock(0, &backtrace_flag);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) put_cpu();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) // Dump stacks even for idle CPUs.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) static bool backtrace_idle;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) module_param(backtrace_idle, bool, 0644);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) bool nmi_cpu_backtrace(struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) int cpu = smp_processor_id();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) if (!READ_ONCE(backtrace_idle) && regs && cpu_in_idle(instruction_pointer(regs))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) pr_warn("NMI backtrace for cpu %d skipped: idling at %pS\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) cpu, (void *)instruction_pointer(regs));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) pr_warn("NMI backtrace for cpu %d\n", cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) if (regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) show_regs(regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) dump_stack();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) NOKPROBE_SYMBOL(nmi_cpu_backtrace);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) #endif
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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