Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (27 commits)
  perf_counter: Zero dead bytes from ftrace raw samples size alignment
  perf_counter: Subtract the buffer size field from the event record size
  perf_counter: Require CAP_SYS_ADMIN for raw tracepoint data
  perf_counter: Correct PERF_SAMPLE_RAW output
  perf tools: callchain: Fix bad rounding of minimum rate
  perf_counter tools: Fix libbfd detection for systems with libz dependency
  perf: "Longum est iter per praecepta, breve et efficax per exempla"
  perf_counter: Fix a race on perf_counter_ctx
  perf_counter: Fix tracepoint sampling to be part of generic sampling
  perf_counter: Work around gcc warning by initializing tracepoint record unconditionally
  perf tools: callchain: Fix sum of percentages to be 100% by displaying amount of ignored chains in fractal mode
  perf tools: callchain: Fix 'perf report' display to be callchain by default
  perf tools: callchain: Fix spurious 'perf report' warnings: ignore empty callchains
  perf record: Fix the -A UI for empty or non-existent perf.data
  perf util: Fix do_read() to fail on EOF instead of busy-looping
  perf list: Fix the output to not include tracepoints without an id
  perf_counter/powerpc: Fix oops on cpus without perf_counter hardware support
  perf stat: Fix tool option consistency: rename -S/--scale to -c/--scale
  perf report: Add debug help for the finding of symbol bugs - show the symtab origin (DSO, build-id, kernel, etc)
  perf report: Fix per task mult-counter stat reporting
  ...

1 files changed, 145 insertions, 94 deletions

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 868102172aa4..b0b20a07f394 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2646,7 +2646,6 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
                 u64 counter;
         } group_entry;
         struct perf_callchain_entry *callchain = NULL;
-        struct perf_tracepoint_record *tp;
         int callchain_size = 0;
         u64 time;
         struct {
@@ -2715,9 +2714,16 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
                         header.size += sizeof(u64);
         }
 
-        if (sample_type & PERF_SAMPLE_TP_RECORD) {
-                tp = data->private;
-                header.size += tp->size;
+        if (sample_type & PERF_SAMPLE_RAW) {
+                int size = sizeof(u32);
+
+                if (data->raw)
+                        size += data->raw->size;
+                else
+                        size += sizeof(u32);
+
+                WARN_ON_ONCE(size & (sizeof(u64)-1));
+                header.size += size;
         }
 
         ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
@@ -2783,8 +2789,21 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
                 }
         }
 
-        if (sample_type & PERF_SAMPLE_TP_RECORD)
-                perf_output_copy(&handle, tp->record, tp->size);
+        if (sample_type & PERF_SAMPLE_RAW) {
+                if (data->raw) {
+                        perf_output_put(&handle, data->raw->size);
+                        perf_output_copy(&handle, data->raw->data, data->raw->size);
+                } else {
+                        struct {
+                                u32     size;
+                                u32     data;
+                        } raw = {
+                                .size = sizeof(u32),
+                                .data = 0,
+                        };
+                        perf_output_put(&handle, raw);
+                }
+        }
 
         perf_output_end(&handle);
 }
@@ -2849,7 +2868,8 @@ perf_counter_read_event(struct perf_counter *counter,
  */
 
 struct perf_task_event {
-        struct task_struct      *task;
+        struct task_struct              *task;
+        struct perf_counter_context     *task_ctx;
 
         struct {
                 struct perf_event_header        header;
@@ -2909,24 +2929,23 @@ static void perf_counter_task_ctx(struct perf_counter_context *ctx,
 static void perf_counter_task_event(struct perf_task_event *task_event)
 {
         struct perf_cpu_context *cpuctx;
-        struct perf_counter_context *ctx;
+        struct perf_counter_context *ctx = task_event->task_ctx;
 
         cpuctx = &get_cpu_var(perf_cpu_context);
         perf_counter_task_ctx(&cpuctx->ctx, task_event);
         put_cpu_var(perf_cpu_context);
 
         rcu_read_lock();
-        /*
-         * doesn't really matter which of the child contexts the
-         * events ends up in.
-         */
-        ctx = rcu_dereference(current->perf_counter_ctxp);
+        if (!ctx)
+                ctx = rcu_dereference(task_event->task->perf_counter_ctxp);
         if (ctx)
                 perf_counter_task_ctx(ctx, task_event);
         rcu_read_unlock();
 }
 
-static void perf_counter_task(struct task_struct *task, int new)
+static void perf_counter_task(struct task_struct *task,
+                              struct perf_counter_context *task_ctx,
+                              int new)
 {
         struct perf_task_event task_event;
 
@@ -2936,8 +2955,9 @@ static void perf_counter_task(struct task_struct *task, int new)
                 return;
 
         task_event = (struct perf_task_event){
-                .task   = task,
-                .event  = {
+                .task     = task,
+                .task_ctx = task_ctx,
+                .event    = {
                         .header = {
                                 .type = new ? PERF_EVENT_FORK : PERF_EVENT_EXIT,
                                 .misc = 0,
@@ -2955,7 +2975,7 @@ static void perf_counter_task(struct task_struct *task, int new)
 
 void perf_counter_fork(struct task_struct *task)
 {
-        perf_counter_task(task, 1);
+        perf_counter_task(task, NULL, 1);
 }
 
 /*
@@ -3344,87 +3364,81 @@ int perf_counter_overflow(struct perf_counter *counter, int nmi,
  * Generic software counter infrastructure
  */
 
-static void perf_swcounter_update(struct perf_counter *counter)
+/*
+ * We directly increment counter->count and keep a second value in
+ * counter->hw.period_left to count intervals. This period counter
+ * is kept in the range [-sample_period, 0] so that we can use the
+ * sign as trigger.
+ */
+
+static u64 perf_swcounter_set_period(struct perf_counter *counter)
 {
         struct hw_perf_counter *hwc = &counter->hw;
-        u64 prev, now;
-        s64 delta;
+        u64 period = hwc->last_period;
+        u64 nr, offset;
+        s64 old, val;
+
+        hwc->last_period = hwc->sample_period;
 
 again:
-        prev = atomic64_read(&hwc->prev_count);
-        now = atomic64_read(&hwc->count);
-        if (atomic64_cmpxchg(&hwc->prev_count, prev, now) != prev)
-                goto again;
+        old = val = atomic64_read(&hwc->period_left);
+        if (val < 0)
+                return 0;
 
-        delta = now - prev;
+        nr = div64_u64(period + val, period);
+        offset = nr * period;
+        val -= offset;
+        if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
+                goto again;
 
-        atomic64_add(delta, &counter->count);
-        atomic64_sub(delta, &hwc->period_left);
+        return nr;
 }
 
-static void perf_swcounter_set_period(struct perf_counter *counter)
+static void perf_swcounter_overflow(struct perf_counter *counter,
+                                    int nmi, struct perf_sample_data *data)
 {
         struct hw_perf_counter *hwc = &counter->hw;
-        s64 left = atomic64_read(&hwc->period_left);
-        s64 period = hwc->sample_period;
+        u64 overflow;
 
-        if (unlikely(left <= -period)) {
-                left = period;
-                atomic64_set(&hwc->period_left, left);
-                hwc->last_period = period;
-        }
+        data->period = counter->hw.last_period;
+        overflow = perf_swcounter_set_period(counter);
 
-        if (unlikely(left <= 0)) {
-                left += period;
-                atomic64_add(period, &hwc->period_left);
-                hwc->last_period = period;
-        }
+        if (hwc->interrupts == MAX_INTERRUPTS)
+                return;
 
-        atomic64_set(&hwc->prev_count, -left);
-        atomic64_set(&hwc->count, -left);
+        for (; overflow; overflow--) {
+                if (perf_counter_overflow(counter, nmi, data)) {
+                        /*
+                         * We inhibit the overflow from happening when
+                         * hwc->interrupts == MAX_INTERRUPTS.
+                         */
+                        break;
+                }
+        }
 }
 
-static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
+static void perf_swcounter_unthrottle(struct perf_counter *counter)
 {
-        enum hrtimer_restart ret = HRTIMER_RESTART;
-        struct perf_sample_data data;
-        struct perf_counter *counter;
-        u64 period;
-
-        counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
-        counter->pmu->read(counter);
-
-        data.addr = 0;
-        data.regs = get_irq_regs();
         /*
-         * In case we exclude kernel IPs or are somehow not in interrupt
-         * context, provide the next best thing, the user IP.
+         * Nothing to do, we already reset hwc->interrupts.
          */
-        if ((counter->attr.exclude_kernel || !data.regs) &&
-                        !counter->attr.exclude_user)
-                data.regs = task_pt_regs(current);
+}
 
-        if (data.regs) {
-                if (perf_counter_overflow(counter, 0, &data))
-                        ret = HRTIMER_NORESTART;
-        }
+static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
+                               int nmi, struct perf_sample_data *data)
+{
+        struct hw_perf_counter *hwc = &counter->hw;
 
-        period = max_t(u64, 10000, counter->hw.sample_period);
-        hrtimer_forward_now(hrtimer, ns_to_ktime(period));
+        atomic64_add(nr, &counter->count);
 
-        return ret;
-}
+        if (!hwc->sample_period)
+                return;
 
-static void perf_swcounter_overflow(struct perf_counter *counter,
-                                    int nmi, struct perf_sample_data *data)
-{
-        data->period = counter->hw.last_period;
+        if (!data->regs)
+                return;
 
-        perf_swcounter_update(counter);
-        perf_swcounter_set_period(counter);
-        if (perf_counter_overflow(counter, nmi, data))
-                /* soft-disable the counter */
-                ;
+        if (!atomic64_add_negative(nr, &hwc->period_left))
+                perf_swcounter_overflow(counter, nmi, data);
 }
 
 static int perf_swcounter_is_counting(struct perf_counter *counter)
@@ -3488,15 +3502,6 @@ static int perf_swcounter_match(struct perf_counter *counter,
         return 1;
 }
 
-static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
-                               int nmi, struct perf_sample_data *data)
-{
-        int neg = atomic64_add_negative(nr, &counter->hw.count);
-
-        if (counter->hw.sample_period && !neg && data->regs)
-                perf_swcounter_overflow(counter, nmi, data);
-}
-
 static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
                                      enum perf_type_id type,
                                      u32 event, u64 nr, int nmi,
@@ -3575,27 +3580,66 @@ void __perf_swcounter_event(u32 event, u64 nr, int nmi,
 
 static void perf_swcounter_read(struct perf_counter *counter)
 {
-        perf_swcounter_update(counter);
 }
 
 static int perf_swcounter_enable(struct perf_counter *counter)
 {
-        perf_swcounter_set_period(counter);
+        struct hw_perf_counter *hwc = &counter->hw;
+
+        if (hwc->sample_period) {
+                hwc->last_period = hwc->sample_period;
+                perf_swcounter_set_period(counter);
+        }
         return 0;
 }
 
 static void perf_swcounter_disable(struct perf_counter *counter)
 {
-        perf_swcounter_update(counter);
 }
 
 static const struct pmu perf_ops_generic = {
         .enable         = perf_swcounter_enable,
         .disable        = perf_swcounter_disable,
         .read           = perf_swcounter_read,
+        .unthrottle     = perf_swcounter_unthrottle,
 };
 
 /*
+ * hrtimer based swcounter callback
+ */
+
+static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
+{
+        enum hrtimer_restart ret = HRTIMER_RESTART;
+        struct perf_sample_data data;
+        struct perf_counter *counter;
+        u64 period;
+
+        counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
+        counter->pmu->read(counter);
+
+        data.addr = 0;
+        data.regs = get_irq_regs();
+        /*
+         * In case we exclude kernel IPs or are somehow not in interrupt
+         * context, provide the next best thing, the user IP.
+         */
+        if ((counter->attr.exclude_kernel || !data.regs) &&
+                        !counter->attr.exclude_user)
+                data.regs = task_pt_regs(current);
+
+        if (data.regs) {
+                if (perf_counter_overflow(counter, 0, &data))
+                        ret = HRTIMER_NORESTART;
+        }
+
+        period = max_t(u64, 10000, counter->hw.sample_period);
+        hrtimer_forward_now(hrtimer, ns_to_ktime(period));
+
+        return ret;
+}
+
+/*
  * Software counter: cpu wall time clock
  */
 
@@ -3715,15 +3759,15 @@ static const struct pmu perf_ops_task_clock = {
 void perf_tpcounter_event(int event_id, u64 addr, u64 count, void *record,
                           int entry_size)
 {
-        struct perf_tracepoint_record tp = {
+        struct perf_raw_record raw = {
                 .size = entry_size,
-                .record = record,
+                .data = record,
         };
 
         struct perf_sample_data data = {
                 .regs = get_irq_regs(),
                 .addr = addr,
-                .private = &tp,
+                .raw = &raw,
         };
 
         if (!data.regs)
@@ -3743,6 +3787,14 @@ static void tp_perf_counter_destroy(struct perf_counter *counter)
 
 static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
 {
+        /*
+         * Raw tracepoint data is a severe data leak, only allow root to
+         * have these.
+         */
+        if ((counter->attr.sample_type & PERF_SAMPLE_RAW) &&
+                        !capable(CAP_SYS_ADMIN))
+                return ERR_PTR(-EPERM);
+
         if (ftrace_profile_enable(counter->attr.config))
                 return NULL;
 
@@ -4285,7 +4337,7 @@ void perf_counter_exit_task(struct task_struct *child)
         unsigned long flags;
 
         if (likely(!child->perf_counter_ctxp)) {
-                perf_counter_task(child, 0);
+                perf_counter_task(child, NULL, 0);
                 return;
         }
 
@@ -4305,6 +4357,7 @@ void perf_counter_exit_task(struct task_struct *child)
          * incremented the context's refcount before we do put_ctx below.
          */
         spin_lock(&child_ctx->lock);
+        child->perf_counter_ctxp = NULL;
         /*
          * If this context is a clone; unclone it so it can't get
          * swapped to another process while we're removing all
@@ -4318,9 +4371,7 @@ void perf_counter_exit_task(struct task_struct *child)
          * won't get any samples after PERF_EVENT_EXIT. We can however still
          * get a few PERF_EVENT_READ events.
          */
-        perf_counter_task(child, 0);
-
-        child->perf_counter_ctxp = NULL;
+        perf_counter_task(child, child_ctx, 0);
 
         /*
          * We can recurse on the same lock type through: