#include <linux/sched.h>
#include <linux/init.h>
#include <linux/slab.h>
+#include <linux/list.h>
#include <linux/cpu.h>
#include <linux/smp.h>
static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned[TYPE_MAX]);
/* Number of pinned task breakpoints in a cpu */
-static DEFINE_PER_CPU(unsigned int, *nr_task_bp_pinned[TYPE_MAX]);
+static DEFINE_PER_CPU(unsigned int *, nr_task_bp_pinned[TYPE_MAX]);
/* Number of non-pinned cpu/task breakpoints in a cpu */
static DEFINE_PER_CPU(unsigned int, nr_bp_flexible[TYPE_MAX]);
static int nr_slots[TYPE_MAX];
+/* Keep track of the breakpoints attached to tasks */
+static LIST_HEAD(bp_task_head);
+
static int constraints_initialized;
/* Gather the number of total pinned and un-pinned bp in a cpuset */
return 0;
}
-static int task_bp_pinned(struct task_struct *tsk, enum bp_type_idx type)
+/*
+ * Count the number of breakpoints of the same type and same task.
+ * The given event must be not on the list.
+ */
+static int task_bp_pinned(struct perf_event *bp, enum bp_type_idx type)
{
- struct perf_event_context *ctx = tsk->perf_event_ctxp;
- struct list_head *list;
- struct perf_event *bp;
- unsigned long flags;
+ struct task_struct *tsk = bp->hw.bp_target;
+ struct perf_event *iter;
int count = 0;
- if (WARN_ONCE(!ctx, "No perf context for this task"))
- return 0;
-
- list = &ctx->event_list;
-
- raw_spin_lock_irqsave(&ctx->lock, flags);
-
- /*
- * The current breakpoint counter is not included in the list
- * at the open() callback time
- */
- list_for_each_entry(bp, list, event_entry) {
- if (bp->attr.type == PERF_TYPE_BREAKPOINT)
- if (find_slot_idx(bp) == type)
- count += hw_breakpoint_weight(bp);
+ list_for_each_entry(iter, &bp_task_head, hw.bp_list) {
+ if (iter->hw.bp_target == tsk && find_slot_idx(iter) == type)
+ count += hw_breakpoint_weight(iter);
}
- raw_spin_unlock_irqrestore(&ctx->lock, flags);
-
return count;
}
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);
if (!tsk)
slots->pinned += max_task_bp_pinned(cpu, type);
else
- slots->pinned += task_bp_pinned(tsk, type);
+ slots->pinned += task_bp_pinned(bp, type);
slots->flexible = per_cpu(nr_bp_flexible[type], cpu);
return;
if (!tsk)
nr += max_task_bp_pinned(cpu, type);
else
- nr += task_bp_pinned(tsk, type);
+ nr += task_bp_pinned(bp, type);
if (nr > slots->pinned)
slots->pinned = nr;
/*
* Add a pinned breakpoint for the given task in our constraint table
*/
-static void toggle_bp_task_slot(struct task_struct *tsk, int cpu, bool enable,
+static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable,
enum bp_type_idx type, int weight)
{
unsigned int *tsk_pinned;
int old_idx = 0;
int idx = 0;
- old_count = task_bp_pinned(tsk, type);
+ old_count = task_bp_pinned(bp, type);
old_idx = old_count - 1;
idx = old_idx + weight;
+ /* tsk_pinned[n] is the number of tasks having n breakpoints */
tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu);
if (enable) {
tsk_pinned[idx]++;
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) {
+
+ if (enable)
+ per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight;
+ else
+ per_cpu(nr_cpu_bp_pinned[type], bp->cpu) -= weight;
+ return;
+ }
/* Pinned counter task profiling */
- if (tsk) {
- if (cpu >= 0) {
- toggle_bp_task_slot(tsk, cpu, enable, type, weight);
- return;
- }
+ if (!enable)
+ list_del(&bp->hw.bp_list);
+
+ if (cpu >= 0) {
+ toggle_bp_task_slot(bp, cpu, enable, type, weight);
+ } else {
for_each_online_cpu(cpu)
- toggle_bp_task_slot(tsk, cpu, enable, type, weight);
- return;
+ toggle_bp_task_slot(bp, cpu, enable, type, weight);
}
- /* Pinned counter cpu profiling */
if (enable)
- per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight;
- else
- per_cpu(nr_cpu_bp_pinned[type], bp->cpu) -= weight;
+ list_add_tail(&bp->hw.bp_list, &bp_task_head);
+}
+
+/*
+ * Function to perform processor-specific cleanup during unregistration
+ */
+__weak void arch_unregister_hw_breakpoint(struct perf_event *bp)
+{
+ /*
+ * A weak stub function here for those archs that don't define
+ * it inside arch/.../kernel/hw_breakpoint.c
+ */
}
/*
weight = hw_breakpoint_weight(bp);
fetch_bp_busy_slots(&slots, bp, type);
+ /*
+ * Simulate the addition of this breakpoint to the constraints
+ * and see the result.
+ */
fetch_this_slot(&slots, weight);
/* Flexible counters need to keep at least one slot */
{
mutex_lock(&nr_bp_mutex);
+ arch_unregister_hw_breakpoint(bp);
__release_bp_slot(bp);
mutex_unlock(&nr_bp_mutex);
perf_overflow_handler_t triggered,
struct task_struct *tsk)
{
- return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered);
+ return perf_event_create_kernel_counter(attr, -1, tsk, triggered);
}
EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
get_online_cpus();
for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(cpu_events, cpu);
- bp = perf_event_create_kernel_counter(attr, cpu, -1, triggered);
+ bp = perf_event_create_kernel_counter(attr, cpu, NULL, triggered);
*pevent = bp;
.priority = 0x7fffffff
};
-static int __init init_hw_breakpoint(void)
+static void bp_perf_event_destroy(struct perf_event *event)
+{
+ release_bp_slot(event);
+}
+
+static int hw_breakpoint_event_init(struct perf_event *bp)
+{
+ int err;
+
+ if (bp->attr.type != PERF_TYPE_BREAKPOINT)
+ return -ENOENT;
+
+ err = register_perf_hw_breakpoint(bp);
+ if (err)
+ return err;
+
+ bp->destroy = bp_perf_event_destroy;
+
+ return 0;
+}
+
+static int hw_breakpoint_add(struct perf_event *bp, int flags)
+{
+ if (!(flags & PERF_EF_START))
+ bp->hw.state = PERF_HES_STOPPED;
+
+ return arch_install_hw_breakpoint(bp);
+}
+
+static void hw_breakpoint_del(struct perf_event *bp, int flags)
+{
+ arch_uninstall_hw_breakpoint(bp);
+}
+
+static void hw_breakpoint_start(struct perf_event *bp, int flags)
+{
+ bp->hw.state = 0;
+}
+
+static void hw_breakpoint_stop(struct perf_event *bp, int flags)
+{
+ bp->hw.state = PERF_HES_STOPPED;
+}
+
+static struct pmu perf_breakpoint = {
+ .task_ctx_nr = perf_sw_context, /* could eventually get its own */
+
+ .event_init = hw_breakpoint_event_init,
+ .add = hw_breakpoint_add,
+ .del = hw_breakpoint_del,
+ .start = hw_breakpoint_start,
+ .stop = hw_breakpoint_stop,
+ .read = hw_breakpoint_pmu_read,
+};
+
+int __init init_hw_breakpoint(void)
{
unsigned int **task_bp_pinned;
int cpu, err_cpu;
constraints_initialized = 1;
+ perf_pmu_register(&perf_breakpoint, "breakpoint", PERF_TYPE_BREAKPOINT);
+
return register_die_notifier(&hw_breakpoint_exceptions_nb);
err_alloc:
return -ENOMEM;
}
-core_initcall(init_hw_breakpoint);
-struct pmu perf_ops_bp = {
- .enable = arch_install_hw_breakpoint,
- .disable = arch_uninstall_hw_breakpoint,
- .read = hw_breakpoint_pmu_read,
-};
projects / linux-flexiantxendom0-natty.git / blobdiff