diff options
Diffstat (limited to 'kernel/perf_counter.c')
-rw-r--r-- | kernel/perf_counter.c | 193 |
1 files changed, 155 insertions, 38 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 534e20d14d6..e0d91fdf0c3 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -46,11 +46,17 @@ static atomic_t nr_task_counters __read_mostly; /* * perf counter paranoia level: - * 0 - not paranoid - * 1 - disallow cpu counters to unpriv - * 2 - disallow kernel profiling to unpriv + * -1 - not paranoid at all + * 0 - disallow raw tracepoint access for unpriv + * 1 - disallow cpu counters for unpriv + * 2 - disallow kernel profiling for unpriv */ -int sysctl_perf_counter_paranoid __read_mostly; +int sysctl_perf_counter_paranoid __read_mostly = 1; + +static inline bool perf_paranoid_tracepoint_raw(void) +{ + return sysctl_perf_counter_paranoid > -1; +} static inline bool perf_paranoid_cpu(void) { @@ -469,7 +475,8 @@ static void update_counter_times(struct perf_counter *counter) struct perf_counter_context *ctx = counter->ctx; u64 run_end; - if (counter->state < PERF_COUNTER_STATE_INACTIVE) + if (counter->state < PERF_COUNTER_STATE_INACTIVE || + counter->group_leader->state < PERF_COUNTER_STATE_INACTIVE) return; counter->total_time_enabled = ctx->time - counter->tstamp_enabled; @@ -518,7 +525,7 @@ static void __perf_counter_disable(void *info) */ if (counter->state >= PERF_COUNTER_STATE_INACTIVE) { update_context_time(ctx); - update_counter_times(counter); + update_group_times(counter); if (counter == counter->group_leader) group_sched_out(counter, cpuctx, ctx); else @@ -573,7 +580,7 @@ static void perf_counter_disable(struct perf_counter *counter) * in, so we can change the state safely. */ if (counter->state == PERF_COUNTER_STATE_INACTIVE) { - update_counter_times(counter); + update_group_times(counter); counter->state = PERF_COUNTER_STATE_OFF; } @@ -851,6 +858,27 @@ retry: } /* + * Put a counter into inactive state and update time fields. + * Enabling the leader of a group effectively enables all + * the group members that aren't explicitly disabled, so we + * have to update their ->tstamp_enabled also. + * Note: this works for group members as well as group leaders + * since the non-leader members' sibling_lists will be empty. + */ +static void __perf_counter_mark_enabled(struct perf_counter *counter, + struct perf_counter_context *ctx) +{ + struct perf_counter *sub; + + counter->state = PERF_COUNTER_STATE_INACTIVE; + counter->tstamp_enabled = ctx->time - counter->total_time_enabled; + list_for_each_entry(sub, &counter->sibling_list, list_entry) + if (sub->state >= PERF_COUNTER_STATE_INACTIVE) + sub->tstamp_enabled = + ctx->time - sub->total_time_enabled; +} + +/* * Cross CPU call to enable a performance counter */ static void __perf_counter_enable(void *info) @@ -877,8 +905,7 @@ static void __perf_counter_enable(void *info) if (counter->state >= PERF_COUNTER_STATE_INACTIVE) goto unlock; - counter->state = PERF_COUNTER_STATE_INACTIVE; - counter->tstamp_enabled = ctx->time - counter->total_time_enabled; + __perf_counter_mark_enabled(counter, ctx); /* * If the counter is in a group and isn't the group leader, @@ -971,11 +998,9 @@ static void perf_counter_enable(struct perf_counter *counter) * Since we have the lock this context can't be scheduled * in, so we can change the state safely. */ - if (counter->state == PERF_COUNTER_STATE_OFF) { - counter->state = PERF_COUNTER_STATE_INACTIVE; - counter->tstamp_enabled = - ctx->time - counter->total_time_enabled; - } + if (counter->state == PERF_COUNTER_STATE_OFF) + __perf_counter_mark_enabled(counter, ctx); + out: spin_unlock_irq(&ctx->lock); } @@ -1479,9 +1504,7 @@ static void perf_counter_enable_on_exec(struct task_struct *task) counter->attr.enable_on_exec = 0; if (counter->state >= PERF_COUNTER_STATE_INACTIVE) continue; - counter->state = PERF_COUNTER_STATE_INACTIVE; - counter->tstamp_enabled = - ctx->time - counter->total_time_enabled; + __perf_counter_mark_enabled(counter, ctx); enabled = 1; } @@ -1503,10 +1526,21 @@ static void perf_counter_enable_on_exec(struct task_struct *task) */ static void __perf_counter_read(void *info) { + struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_counter *counter = info; struct perf_counter_context *ctx = counter->ctx; unsigned long flags; + /* + * If this is a task context, we need to check whether it is + * the current task context of this cpu. If not it has been + * scheduled out before the smp call arrived. In that case + * counter->count would have been updated to a recent sample + * when the counter was scheduled out. + */ + if (ctx->task && cpuctx->task_ctx != ctx) + return; + local_irq_save(flags); if (ctx->is_active) update_context_time(ctx); @@ -1664,6 +1698,11 @@ static void free_counter(struct perf_counter *counter) atomic_dec(&nr_task_counters); } + if (counter->output) { + fput(counter->output->filp); + counter->output = NULL; + } + if (counter->destroy) counter->destroy(counter); @@ -1780,7 +1819,7 @@ static int perf_counter_read_group(struct perf_counter *counter, size += err; list_for_each_entry(sub, &leader->sibling_list, list_entry) { - err = perf_counter_read_entry(counter, read_format, + err = perf_counter_read_entry(sub, read_format, buf + size); if (err < 0) return err; @@ -1949,6 +1988,8 @@ unlock: return ret; } +int perf_counter_set_output(struct perf_counter *counter, int output_fd); + static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct perf_counter *counter = file->private_data; @@ -1972,6 +2013,9 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case PERF_COUNTER_IOC_PERIOD: return perf_counter_period(counter, (u64 __user *)arg); + case PERF_COUNTER_IOC_SET_OUTPUT: + return perf_counter_set_output(counter, arg); + default: return -ENOTTY; } @@ -2008,6 +2052,10 @@ int perf_counter_task_disable(void) return 0; } +#ifndef PERF_COUNTER_INDEX_OFFSET +# define PERF_COUNTER_INDEX_OFFSET 0 +#endif + static int perf_counter_index(struct perf_counter *counter) { if (counter->state != PERF_COUNTER_STATE_ACTIVE) @@ -2238,6 +2286,11 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) WARN_ON_ONCE(counter->ctx->parent_ctx); mutex_lock(&counter->mmap_mutex); + if (counter->output) { + ret = -EINVAL; + goto unlock; + } + if (atomic_inc_not_zero(&counter->mmap_count)) { if (nr_pages != counter->data->nr_pages) ret = -EINVAL; @@ -2623,6 +2676,7 @@ static int perf_output_begin(struct perf_output_handle *handle, struct perf_counter *counter, unsigned int size, int nmi, int sample) { + struct perf_counter *output_counter; struct perf_mmap_data *data; unsigned int offset, head; int have_lost; @@ -2632,13 +2686,17 @@ static int perf_output_begin(struct perf_output_handle *handle, u64 lost; } lost_event; + rcu_read_lock(); /* * For inherited counters we send all the output towards the parent. */ if (counter->parent) counter = counter->parent; - rcu_read_lock(); + output_counter = rcu_dereference(counter->output); + if (output_counter) + counter = output_counter; + data = rcu_dereference(counter->data); if (!data) goto out; @@ -3919,6 +3977,7 @@ static const struct pmu *tp_perf_counter_init(struct perf_counter *counter) * have these. */ if ((counter->attr.sample_type & PERF_SAMPLE_RAW) && + perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); @@ -4051,6 +4110,7 @@ perf_counter_alloc(struct perf_counter_attr *attr, hwc->sample_period = attr->sample_period; if (attr->freq && attr->sample_freq) hwc->sample_period = 1; + hwc->last_period = hwc->sample_period; atomic64_set(&hwc->period_left, hwc->sample_period); @@ -4186,6 +4246,57 @@ err_size: goto out; } +int perf_counter_set_output(struct perf_counter *counter, int output_fd) +{ + struct perf_counter *output_counter = NULL; + struct file *output_file = NULL; + struct perf_counter *old_output; + int fput_needed = 0; + int ret = -EINVAL; + + if (!output_fd) + goto set; + + output_file = fget_light(output_fd, &fput_needed); + if (!output_file) + return -EBADF; + + if (output_file->f_op != &perf_fops) + goto out; + + output_counter = output_file->private_data; + + /* Don't chain output fds */ + if (output_counter->output) + goto out; + + /* Don't set an output fd when we already have an output channel */ + if (counter->data) + goto out; + + atomic_long_inc(&output_file->f_count); + +set: + mutex_lock(&counter->mmap_mutex); + old_output = counter->output; + rcu_assign_pointer(counter->output, output_counter); + mutex_unlock(&counter->mmap_mutex); + + if (old_output) { + /* + * we need to make sure no existing perf_output_*() + * is still referencing this counter. + */ + synchronize_rcu(); + fput(old_output->filp); + } + + ret = 0; +out: + fput_light(output_file, fput_needed); + return ret; +} + /** * sys_perf_counter_open - open a performance counter, associate it to a task/cpu * @@ -4205,15 +4316,15 @@ SYSCALL_DEFINE5(perf_counter_open, struct file *group_file = NULL; int fput_needed = 0; int fput_needed2 = 0; - int ret; + int err; /* for future expandability... */ - if (flags) + if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT)) return -EINVAL; - ret = perf_copy_attr(attr_uptr, &attr); - if (ret) - return ret; + err = perf_copy_attr(attr_uptr, &attr); + if (err) + return err; if (!attr.exclude_kernel) { if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) @@ -4236,8 +4347,8 @@ SYSCALL_DEFINE5(perf_counter_open, * Look up the group leader (we will attach this counter to it): */ group_leader = NULL; - if (group_fd != -1) { - ret = -EINVAL; + if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) { + err = -EINVAL; group_file = fget_light(group_fd, &fput_needed); if (!group_file) goto err_put_context; @@ -4266,18 +4377,24 @@ SYSCALL_DEFINE5(perf_counter_open, counter = perf_counter_alloc(&attr, cpu, ctx, group_leader, NULL, GFP_KERNEL); - ret = PTR_ERR(counter); + err = PTR_ERR(counter); if (IS_ERR(counter)) goto err_put_context; - ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0); - if (ret < 0) + err = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0); + if (err < 0) goto err_free_put_context; - counter_file = fget_light(ret, &fput_needed2); + counter_file = fget_light(err, &fput_needed2); if (!counter_file) goto err_free_put_context; + if (flags & PERF_FLAG_FD_OUTPUT) { + err = perf_counter_set_output(counter, group_fd); + if (err) + goto err_fput_free_put_context; + } + counter->filp = counter_file; WARN_ON_ONCE(ctx->parent_ctx); mutex_lock(&ctx->mutex); @@ -4291,20 +4408,20 @@ SYSCALL_DEFINE5(perf_counter_open, list_add_tail(&counter->owner_entry, ¤t->perf_counter_list); mutex_unlock(¤t->perf_counter_mutex); +err_fput_free_put_context: fput_light(counter_file, fput_needed2); -out_fput: - fput_light(group_file, fput_needed); - - return ret; - err_free_put_context: - kfree(counter); + if (err < 0) + kfree(counter); err_put_context: - put_ctx(ctx); + if (err < 0) + put_ctx(ctx); + + fput_light(group_file, fput_needed); - goto out_fput; + return err; } /* |