diff options
| -rw-r--r-- | include/linux/perf_event.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/perf_event.h | 10 | ||||
| -rw-r--r-- | kernel/events/core.c | 49 |
3 files changed, 58 insertions, 2 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 1660039199b2..7d7280aa4e22 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -735,6 +735,7 @@ struct perf_event { int pending_wakeup; int pending_kill; int pending_disable; + unsigned long pending_addr; /* SIGTRAP */ struct irq_work pending; atomic_t event_limit; diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 8c5b9f5ad63f..31b00e3b69c9 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -311,6 +311,7 @@ enum perf_event_read_format { #define PERF_ATTR_SIZE_VER4 104 /* add: sample_regs_intr */ #define PERF_ATTR_SIZE_VER5 112 /* add: aux_watermark */ #define PERF_ATTR_SIZE_VER6 120 /* add: aux_sample_size */ +#define PERF_ATTR_SIZE_VER7 128 /* add: sig_data */ /* * Hardware event_id to monitor via a performance monitoring event: @@ -391,7 +392,8 @@ struct perf_event_attr { build_id : 1, /* use build id in mmap2 events */ inherit_thread : 1, /* children only inherit if cloned with CLONE_THREAD */ remove_on_exec : 1, /* event is removed from task on exec */ - __reserved_1 : 27; + sigtrap : 1, /* send synchronous SIGTRAP on event */ + __reserved_1 : 26; union { __u32 wakeup_events; /* wakeup every n events */ @@ -443,6 +445,12 @@ struct perf_event_attr { __u16 __reserved_2; __u32 aux_sample_size; __u32 __reserved_3; + + /* + * User provided data if sigtrap=1, passed back to user via + * siginfo_t::si_perf, e.g. to permit user to identify the event. + */ + __u64 sig_data; }; /* diff --git a/kernel/events/core.c b/kernel/events/core.c index e4a584bceb7a..6f0723c711a9 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6392,6 +6392,33 @@ void perf_event_wakeup(struct perf_event *event) } } +static void perf_sigtrap(struct perf_event *event) +{ + struct kernel_siginfo info; + + /* + * We'd expect this to only occur if the irq_work is delayed and either + * ctx->task or current has changed in the meantime. This can be the + * case on architectures that do not implement arch_irq_work_raise(). + */ + if (WARN_ON_ONCE(event->ctx->task != current)) + return; + + /* + * perf_pending_event() can race with the task exiting. + */ + if (current->flags & PF_EXITING) + return; + + clear_siginfo(&info); + info.si_signo = SIGTRAP; + info.si_code = TRAP_PERF; + info.si_errno = event->attr.type; + info.si_perf = event->attr.sig_data; + info.si_addr = (void __user *)event->pending_addr; + force_sig_info(&info); +} + static void perf_pending_event_disable(struct perf_event *event) { int cpu = READ_ONCE(event->pending_disable); @@ -6401,6 +6428,13 @@ static void perf_pending_event_disable(struct perf_event *event) if (cpu == smp_processor_id()) { WRITE_ONCE(event->pending_disable, -1); + + if (event->attr.sigtrap) { + perf_sigtrap(event); + atomic_set_release(&event->event_limit, 1); /* rearm event */ + return; + } + perf_event_disable_local(event); return; } @@ -9103,6 +9137,7 @@ static int __perf_event_overflow(struct perf_event *event, if (events && atomic_dec_and_test(&event->event_limit)) { ret = 1; event->pending_kill = POLL_HUP; + event->pending_addr = data->addr; perf_event_disable_inatomic(event); } @@ -11384,6 +11419,10 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, if (!task || cpu != -1) return ERR_PTR(-EINVAL); } + if (attr->sigtrap && !task) { + /* Requires a task: avoid signalling random tasks. */ + return ERR_PTR(-EINVAL); + } node = (cpu >= 0) ? cpu_to_node(cpu) : -1; event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, @@ -11432,6 +11471,9 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, event->state = PERF_EVENT_STATE_INACTIVE; + if (event->attr.sigtrap) + atomic_set(&event->event_limit, 1); + if (task) { event->attach_state = PERF_ATTACH_TASK; /* @@ -11710,6 +11752,9 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr, if (attr->remove_on_exec && attr->enable_on_exec) return -EINVAL; + if (attr->sigtrap && !attr->remove_on_exec) + return -EINVAL; + out: return ret; @@ -12936,7 +12981,9 @@ inherit_task_group(struct perf_event *event, struct task_struct *parent, struct perf_event_context *child_ctx; if (!event->attr.inherit || - (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD))) { + (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) || + /* Do not inherit if sigtrap and signal handlers were cleared. */ + (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) { *inherited_all = 0; return 0; } |