path: root/include/linux/perf_event.h
diff options
authorMarco Elver <elver@google.com>2021-04-08 12:36:01 +0200
committerPeter Zijlstra <peterz@infradead.org>2021-04-16 16:32:41 +0200
commit97ba62b278674293762c3d91f724f1bb922f04e0 (patch)
treedc0f53789ab2b9329f5dde2092fa549ce6341412 /include/linux/perf_event.h
parentsignal: Introduce TRAP_PERF si_code and si_perf to siginfo (diff)
perf: Add support for SIGTRAP on perf events
Adds bit perf_event_attr::sigtrap, which can be set to cause events to send SIGTRAP (with si_code TRAP_PERF) to the task where the event occurred. The primary motivation is to support synchronous signals on perf events in the task where an event (such as breakpoints) triggered. To distinguish perf events based on the event type, the type is set in si_errno. For events that are associated with an address, si_addr is copied from perf_sample_data. The new field perf_event_attr::sig_data is copied to si_perf, which allows user space to disambiguate which event (of the same type) triggered the signal. For example, user space could encode the relevant information it cares about in sig_data. We note that the choice of an opaque u64 provides the simplest and most flexible option. Alternatives where a reference to some user space data is passed back suffer from the problem that modification of referenced data (be it the event fd, or the perf_event_attr) can race with the signal being delivered (of course, the same caveat applies if user space decides to store a pointer in sig_data, but the ABI explicitly avoids prescribing such a design). Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Dmitry Vyukov <dvyukov@google.com> Link: https://lore.kernel.org/lkml/YBv3rAT566k+6zjg@hirez.programming.kicks-ass.net/
Diffstat (limited to 'include/linux/perf_event.h')
1 files changed, 1 insertions, 0 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;