Merge branch 'topic/misc' into for-linus

[safe/jmp/linux-2.6] / kernel / hw_breakpoint.c

diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 50dbd59..03808ed 100644 (file)
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -243,38 +243,70 @@ static void toggle_bp_slot(struct perf_event *bp, bool enable)
  *       ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *))
  *            + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM
  */
-int reserve_bp_slot(struct perf_event *bp)
+static int __reserve_bp_slot(struct perf_event *bp)
 {
        struct bp_busy_slots slots = {0};
-       int ret = 0;
-
-       mutex_lock(&nr_bp_mutex);
 
        fetch_bp_busy_slots(&slots, bp);
 
        /* Flexible counters need to keep at least one slot */
-       if (slots.pinned + (!!slots.flexible) == HBP_NUM) {
-               ret = -ENOSPC;
-               goto end;
-       }
+       if (slots.pinned + (!!slots.flexible) == HBP_NUM)
+               return -ENOSPC;
 
        toggle_bp_slot(bp, true);
 
-end:
+       return 0;
+}
+
+int reserve_bp_slot(struct perf_event *bp)
+{
+       int ret;
+
+       mutex_lock(&nr_bp_mutex);
+
+       ret = __reserve_bp_slot(bp);
+
        mutex_unlock(&nr_bp_mutex);
 
        return ret;
 }
 
+static void __release_bp_slot(struct perf_event *bp)
+{
+       toggle_bp_slot(bp, false);
+}
+
 void release_bp_slot(struct perf_event *bp)
 {
        mutex_lock(&nr_bp_mutex);
 
-       toggle_bp_slot(bp, false);
+       __release_bp_slot(bp);
 
        mutex_unlock(&nr_bp_mutex);
 }
 
+/*
+ * Allow the kernel debugger to reserve breakpoint slots without
+ * taking a lock using the dbg_* variant of for the reserve and
+ * release breakpoint slots.
+ */
+int dbg_reserve_bp_slot(struct perf_event *bp)
+{
+       if (mutex_is_locked(&nr_bp_mutex))
+               return -1;
+
+       return __reserve_bp_slot(bp);
+}
+
+int dbg_release_bp_slot(struct perf_event *bp)
+{
+       if (mutex_is_locked(&nr_bp_mutex))
+               return -1;
+
+       __release_bp_slot(bp);
+
+       return 0;
+}
 
 int register_perf_hw_breakpoint(struct perf_event *bp)
 {
@@ -296,6 +328,10 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
        if (!bp->attr.disabled || !bp->overflow_handler)
                ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
 
+       /* if arch_validate_hwbkpt_settings() fails then release bp slot */
+       if (ret)
+               release_bp_slot(bp);
+
        return ret;
 }
 
@@ -324,8 +360,8 @@ EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
 int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
 {
        u64 old_addr = bp->attr.bp_addr;
+       u64 old_len = bp->attr.bp_len;
        int old_type = bp->attr.bp_type;
-       int old_len = bp->attr.bp_len;
        int err = 0;
 
        perf_event_disable(bp);
@@ -377,17 +413,17 @@ EXPORT_SYMBOL_GPL(unregister_hw_breakpoint);
  *
  * @return a set of per_cpu pointers to perf events
  */
-struct perf_event **
+struct perf_event * __percpu *
 register_wide_hw_breakpoint(struct perf_event_attr *attr,
                            perf_overflow_handler_t triggered)
 {
-       struct perf_event **cpu_events, **pevent, *bp;
+       struct perf_event * __percpu *cpu_events, **pevent, *bp;
        long err;
        int cpu;
 
        cpu_events = alloc_percpu(typeof(*cpu_events));
        if (!cpu_events)
-               return ERR_PTR(-ENOMEM);
+               return (void __percpu __force *)ERR_PTR(-ENOMEM);
 
        get_online_cpus();
        for_each_online_cpu(cpu) {
@@ -415,7 +451,7 @@ fail:
        put_online_cpus();
 
        free_percpu(cpu_events);
-       return ERR_PTR(err);
+       return (void __percpu __force *)ERR_PTR(err);
 }
 EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint);
 
@@ -423,7 +459,7 @@ EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint);
  * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel
  * @cpu_events: the per cpu set of events to unregister
  */
-void unregister_wide_hw_breakpoint(struct perf_event **cpu_events)
+void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events)
 {
        int cpu;
        struct perf_event **pevent;
@@ -453,5 +489,4 @@ struct pmu perf_ops_bp = {
        .enable         = arch_install_hw_breakpoint,
        .disable        = arch_uninstall_hw_breakpoint,
        .read           = hw_breakpoint_pmu_read,
-       .unthrottle     = hw_breakpoint_pmu_unthrottle
 };