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-rw-r--r--include/linux/perf_event.h7
-rw-r--r--kernel/hw_breakpoint.c8
-rw-r--r--kernel/perf_event.c23
3 files changed, 29 insertions, 9 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2ebfc9a..97965fa 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -536,6 +536,12 @@ struct hw_perf_event {
struct { /* breakpoint */
struct arch_hw_breakpoint info;
struct list_head bp_list;
+ /*
+ * Crufty hack to avoid the chicken and egg
+ * problem hw_breakpoint has with context
+ * creation and event initalization.
+ */
+ struct task_struct *bp_target;
};
#endif
};
@@ -693,6 +699,7 @@ struct swevent_hlist {
#define PERF_ATTACH_CONTEXT 0x01
#define PERF_ATTACH_GROUP 0x02
+#define PERF_ATTACH_TASK 0x04
/**
* struct perf_event - performance event kernel representation:
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 3b714e8..2c9120f 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -113,12 +113,12 @@ static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type)
*/
static int task_bp_pinned(struct perf_event *bp, enum bp_type_idx type)
{
- struct perf_event_context *ctx = bp->ctx;
+ struct task_struct *tsk = bp->hw.bp_target;
struct perf_event *iter;
int count = 0;
list_for_each_entry(iter, &bp_task_head, hw.bp_list) {
- if (iter->ctx == ctx && find_slot_idx(iter) == type)
+ if (iter->hw.bp_target == tsk && find_slot_idx(iter) == type)
count += hw_breakpoint_weight(iter);
}
@@ -134,7 +134,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
enum bp_type_idx type)
{
int cpu = bp->cpu;
- struct task_struct *tsk = bp->ctx->task;
+ struct task_struct *tsk = bp->hw.bp_target;
if (cpu >= 0) {
slots->pinned = per_cpu(nr_cpu_bp_pinned[type], cpu);
@@ -213,7 +213,7 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
int weight)
{
int cpu = bp->cpu;
- struct task_struct *tsk = bp->ctx->task;
+ struct task_struct *tsk = bp->hw.bp_target;
/* Pinned counter cpu profiling */
if (!tsk) {
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index b21d06a..856e20b 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -5255,9 +5255,10 @@ unlock:
*/
static struct perf_event *
perf_event_alloc(struct perf_event_attr *attr, int cpu,
- struct perf_event *group_leader,
- struct perf_event *parent_event,
- perf_overflow_handler_t overflow_handler)
+ struct task_struct *task,
+ struct perf_event *group_leader,
+ struct perf_event *parent_event,
+ perf_overflow_handler_t overflow_handler)
{
struct pmu *pmu;
struct perf_event *event;
@@ -5299,6 +5300,17 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
event->state = PERF_EVENT_STATE_INACTIVE;
+ if (task) {
+ event->attach_state = PERF_ATTACH_TASK;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+ /*
+ * hw_breakpoint is a bit difficult here..
+ */
+ if (attr->type == PERF_TYPE_BREAKPOINT)
+ event->hw.bp_target = task;
+#endif
+ }
+
if (!overflow_handler && parent_event)
overflow_handler = parent_event->overflow_handler;
@@ -5559,7 +5571,7 @@ SYSCALL_DEFINE5(perf_event_open,
}
}
- event = perf_event_alloc(&attr, cpu, group_leader, NULL, NULL);
+ event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err_task;
@@ -5728,7 +5740,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
* Get the target context (task or percpu):
*/
- event = perf_event_alloc(attr, cpu, NULL, NULL, overflow_handler);
+ event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err;
@@ -5996,6 +6008,7 @@ inherit_event(struct perf_event *parent_event,
child_event = perf_event_alloc(&parent_event->attr,
parent_event->cpu,
+ child,
group_leader, parent_event,
NULL);
if (IS_ERR(child_event))