diff options
| -rw-r--r-- | include/linux/perf_counter.h | 9 | ||||
| -rw-r--r-- | kernel/perf_counter.c | 41 |
2 files changed, 46 insertions, 4 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index c046f7d97cf..45bdd3b95d3 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -164,10 +164,11 @@ struct perf_counter_hw_event { /* * Ioctls that can be done on a perf counter fd: */ -#define PERF_COUNTER_IOC_ENABLE _IOW('$', 0, u32) -#define PERF_COUNTER_IOC_DISABLE _IOW('$', 1, u32) -#define PERF_COUNTER_IOC_REFRESH _IOW('$', 2, u32) -#define PERF_COUNTER_IOC_RESET _IOW('$', 3, u32) +#define PERF_COUNTER_IOC_ENABLE _IO ('$', 0) +#define PERF_COUNTER_IOC_DISABLE _IO ('$', 1) +#define PERF_COUNTER_IOC_REFRESH _IO ('$', 2) +#define PERF_COUNTER_IOC_RESET _IO ('$', 3) +#define PERF_COUNTER_IOC_PERIOD _IOW('$', 4, u64) enum perf_counter_ioc_flags { PERF_IOC_FLAG_GROUP = 1U << 0, diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 3f11a2bc6c7..abe2f3b6c42 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1604,6 +1604,43 @@ static void perf_counter_for_each(struct perf_counter *counter, mutex_unlock(&counter->child_mutex); } +static int perf_counter_period(struct perf_counter *counter, u64 __user *arg) +{ + struct perf_counter_context *ctx = counter->ctx; + unsigned long size; + int ret = 0; + u64 value; + + if (!counter->hw_event.sample_period) + return -EINVAL; + + size = copy_from_user(&value, arg, sizeof(value)); + if (size != sizeof(value)) + return -EFAULT; + + if (!value) + return -EINVAL; + + spin_lock_irq(&ctx->lock); + if (counter->hw_event.freq) { + if (value > sysctl_perf_counter_limit) { + ret = -EINVAL; + goto unlock; + } + + counter->hw_event.sample_freq = value; + } else { + counter->hw_event.sample_period = value; + counter->hw.sample_period = value; + + perf_log_period(counter, value); + } +unlock: + spin_unlock_irq(&ctx->lock); + + return ret; +} + static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct perf_counter *counter = file->private_data; @@ -1623,6 +1660,10 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case PERF_COUNTER_IOC_REFRESH: return perf_counter_refresh(counter, arg); + + case PERF_COUNTER_IOC_PERIOD: + return perf_counter_period(counter, (u64 __user *)arg); + default: return -ENOTTY; } |