diff options
Diffstat (limited to 'arch/tile/kernel/process.c')
| -rw-r--r-- | arch/tile/kernel/process.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c index b403c2e3e263..0dddcf7e5bfa 100644 --- a/arch/tile/kernel/process.c +++ b/arch/tile/kernel/process.c @@ -27,6 +27,7 @@ #include <linux/kernel.h> #include <linux/tracehook.h> #include <linux/signal.h> +#include <linux/delay.h> #include <linux/context_tracking.h> #include <asm/stack.h> #include <asm/switch_to.h> @@ -574,3 +575,103 @@ void show_regs(struct pt_regs *regs) dump_stack_regs(regs); } + +/* To ensure stack dump on tiles occurs one by one. */ +static DEFINE_SPINLOCK(backtrace_lock); +/* To ensure no backtrace occurs before all of the stack dump are done. */ +static atomic_t backtrace_cpus; +/* The cpu mask to avoid reentrance. */ +static struct cpumask backtrace_mask; + +void do_nmi_dump_stack(struct pt_regs *regs) +{ + int is_idle = is_idle_task(current) && !in_interrupt(); + int cpu; + + nmi_enter(); + cpu = smp_processor_id(); + if (WARN_ON_ONCE(!cpumask_test_and_clear_cpu(cpu, &backtrace_mask))) + goto done; + + spin_lock(&backtrace_lock); + if (is_idle) + pr_info("CPU: %d idle\n", cpu); + else + show_regs(regs); + spin_unlock(&backtrace_lock); + atomic_dec(&backtrace_cpus); +done: + nmi_exit(); +} + +#ifdef __tilegx__ +void arch_trigger_all_cpu_backtrace(bool self) +{ + struct cpumask mask; + HV_Coord tile; + unsigned int timeout; + int cpu; + int ongoing; + HV_NMI_Info info[NR_CPUS]; + + ongoing = atomic_cmpxchg(&backtrace_cpus, 0, num_online_cpus() - 1); + if (ongoing != 0) { + pr_err("Trying to do all-cpu backtrace.\n"); + pr_err("But another all-cpu backtrace is ongoing (%d cpus left)\n", + ongoing); + if (self) { + pr_err("Reporting the stack on this cpu only.\n"); + dump_stack(); + } + return; + } + + cpumask_copy(&mask, cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), &mask); + cpumask_copy(&backtrace_mask, &mask); + + /* Backtrace for myself first. */ + if (self) + dump_stack(); + + /* Tentatively dump stack on remote tiles via NMI. */ + timeout = 100; + while (!cpumask_empty(&mask) && timeout) { + for_each_cpu(cpu, &mask) { + tile.x = cpu_x(cpu); + tile.y = cpu_y(cpu); + info[cpu] = hv_send_nmi(tile, TILE_NMI_DUMP_STACK, 0); + if (info[cpu].result == HV_NMI_RESULT_OK) + cpumask_clear_cpu(cpu, &mask); + } + + mdelay(10); + timeout--; + } + + /* Warn about cpus stuck in ICS and decrement their counts here. */ + if (!cpumask_empty(&mask)) { + for_each_cpu(cpu, &mask) { + switch (info[cpu].result) { + case HV_NMI_RESULT_FAIL_ICS: + pr_warn("Skipping stack dump of cpu %d in ICS at pc %#llx\n", + cpu, info[cpu].pc); + break; + case HV_NMI_RESULT_FAIL_HV: + pr_warn("Skipping stack dump of cpu %d in hypervisor\n", + cpu); + break; + case HV_ENOSYS: + pr_warn("Hypervisor too old to allow remote stack dumps.\n"); + goto skip_for_each; + default: /* should not happen */ + pr_warn("Skipping stack dump of cpu %d [%d,%#llx]\n", + cpu, info[cpu].result, info[cpu].pc); + break; + } + } +skip_for_each: + atomic_sub(cpumask_weight(&mask), &backtrace_cpus); + } +} +#endif /* __tilegx_ */ |