[PATCH V5 4/9] perf/core: Adding PMU driver specific configuration
Mathieu Poirier
mathieu.poirier at linaro.org
Thu Aug 11 09:20:59 PDT 2016
This patch somewhat mimics the work done on address filters to
add the infrastructure needed to pass PMU specific HW
configuration to the driver before a session starts.
Signed-off-by: Mathieu Poirier <mathieu.poirier at linaro.org>
---
include/linux/perf_event.h | 31 ++++++
include/uapi/linux/perf_event.h | 1 +
kernel/events/core.c | 179 +++++++++++++++++++++++++++++++++-
tools/include/uapi/linux/perf_event.h | 1 +
4 files changed, 211 insertions(+), 1 deletion(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8ed4326164cc..1ea2028d9848 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -181,6 +181,10 @@ struct hw_perf_event {
/* Last sync'ed generation of filters */
unsigned long addr_filters_gen;
+ /* HW specific configuration */
+ void *drv_configs;
+ raw_spinlock_t drv_configs_lock;
+
/*
* hw_perf_event::state flags; used to track the PERF_EF_* state.
*/
@@ -455,6 +459,13 @@ struct pmu {
* Filter events for PMU-specific reasons.
*/
int (*filter_match) (struct perf_event *event); /* optional */
+
+ /*
+ * PMU driver specific configuration.
+ */
+ int (*set_drv_configs) (struct perf_event *event,
+ struct list_head *drv_configs);
+ /* optional */
};
/**
@@ -492,6 +503,18 @@ struct perf_addr_filters_head {
};
/**
+ * struct perf_drv_config - PMU specific configuration as specified by users
+ * @entry: link to the list.
+ * @config: name of the configuration option.
+ * @option: value associated to @config as set by users(optional).
+ */
+struct perf_drv_config {
+ struct list_head entry;
+ char *config;
+ char *option;
+};
+
+/**
* enum perf_event_active_state - the states of a event
*/
enum perf_event_active_state {
@@ -1194,6 +1217,11 @@ static inline bool has_addr_filter(struct perf_event *event)
return event->pmu->nr_addr_filters;
}
+static inline bool has_drv_config(struct perf_event *event)
+{
+ return event->pmu->set_drv_configs;
+}
+
/*
* An inherited event uses parent's filters
*/
@@ -1209,6 +1237,9 @@ perf_event_addr_filters(struct perf_event *event)
}
extern void perf_event_addr_filters_sync(struct perf_event *event);
+extern void *perf_event_drv_configs_set(struct perf_event *event,
+ void *drv_configs);
+extern void *perf_event_drv_configs_get(struct perf_event *event);
extern int perf_output_begin(struct perf_output_handle *handle,
struct perf_event *event, unsigned int size);
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index c66a485a24ac..90fbc5fd3925 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -407,6 +407,7 @@ struct perf_event_attr {
#define PERF_EVENT_IOC_ID _IOR('$', 7, __u64 *)
#define PERF_EVENT_IOC_SET_BPF _IOW('$', 8, __u32)
#define PERF_EVENT_IOC_PAUSE_OUTPUT _IOW('$', 9, __u32)
+#define PERF_EVENT_IOC_SET_DRV_CONFIGS _IOW('$', 10, char *)
enum perf_event_ioc_flags {
PERF_IOC_FLAG_GROUP = 1U << 0,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b5022836649a..c5c66cc7cd8c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4457,6 +4457,8 @@ static int perf_event_set_output(struct perf_event *event,
struct perf_event *output_event);
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
+static int perf_event_set_drv_configs(struct perf_event *event,
+ void __user *arg);
static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
{
@@ -4526,6 +4528,10 @@ static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned lon
rcu_read_unlock();
return 0;
}
+
+ case PERF_EVENT_IOC_SET_DRV_CONFIGS:
+ return perf_event_set_drv_configs(event, (void __user *)arg);
+
default:
return -ENOTTY;
}
@@ -4558,6 +4564,7 @@ static long perf_compat_ioctl(struct file *file, unsigned int cmd,
switch (_IOC_NR(cmd)) {
case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
case _IOC_NR(PERF_EVENT_IOC_ID):
+ case _IOC_NR(PERF_EVENT_IOC_SET_DRV_CONFIGS):
/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
cmd &= ~IOCSIZE_MASK;
@@ -8044,10 +8051,180 @@ static int perf_event_set_filter(struct perf_event *event, void __user *arg)
return ret;
}
+static struct perf_drv_config *
+perf_drv_config_new(int cpu, struct list_head *drv_config_list)
+{
+ int node = cpu_to_node(cpu == -1 ? 0 : cpu);
+ struct perf_drv_config *drv_config;
+
+ drv_config = kzalloc_node(sizeof(*drv_config), GFP_KERNEL, node);
+ if (!drv_config)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_LIST_HEAD(&drv_config->entry);
+ list_add_tail(&drv_config->entry, drv_config_list);
+
+ return drv_config;
+}
+
+static void free_drv_config_list(struct list_head *drv_config_list)
+{
+ struct perf_drv_config *drv_config, *itr;
+
+ list_for_each_entry_safe(drv_config, itr, drv_config_list, entry) {
+ list_del(&drv_config->entry);
+ kfree(drv_config->config);
+ kfree(drv_config->option);
+ kfree(drv_config);
+ }
+}
+
+/* How long does a configuration option really need to be? */
+#define PERF_DRV_CONFIG_MAX 128
+
/*
- * hrtimer based swevent callback
+ * PMU specific driver configuration as specified from user space.
+ * The data come in the form of an ascii string pushed down to the kernel
+ * using an ioctl() call.
+ *
+ * Two format are accepted: a singleton and in pairs. All of the following
+ * are valid: cfg1, cfg2=config2, cfg3=anything_is_possible.
+ *
+ * It is up to each PMU driver to make sure they can work with the
+ * submitted configurables.
*/
+static int
+perf_event_parse_drv_config(struct perf_event *event, char *options,
+ struct list_head *drv_config_list)
+{
+ char *token;
+ int ret;
+ struct perf_drv_config *drv_config;
+
+ /*
+ * First split the @options string in nibbles. Using the above
+ * example "cfg1", "cfg2=option2" and "cfg3=anything_is_possible"
+ * will be processed.
+ */
+ while ((token = strsep(&options, ",")) != NULL) {
+ char *nibble, *config, *option;
+
+ if (!*token)
+ continue;
+
+ /* Allocate a new driver config structure and queue it. */
+ drv_config = perf_drv_config_new(event->cpu, drv_config_list);
+ if (IS_ERR(drv_config)) {
+ ret = PTR_ERR(drv_config);
+ goto fail;
+ }
+
+ /*
+ * The nibbles are either a "config" or a "config=option"
+ * pair. First get the config part. Since strsep() sets
+ * @nibble to the next valid token, nibble will be equal to
+ * the option part or NULL after the first call.
+ */
+ nibble = token;
+ config = strsep(&nibble, "=");
+ option = nibble;
+
+ /* This shouldn't be happening */
+ if (!config) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ drv_config->config = kstrndup(config,
+ PERF_DRV_CONFIG_MAX, GFP_KERNEL);
+ if (!drv_config->config) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ if (option) {
+ drv_config->option = kstrndup(option,
+ PERF_DRV_CONFIG_MAX,
+ GFP_KERNEL);
+ if (!drv_config->option) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+ }
+ }
+ return 0;
+
+fail:
+ free_drv_config_list(drv_config_list);
+ return ret;
+}
+
+static int
+perf_event_set_drv_configs(struct perf_event *event, void __user *arg)
+{
+ char *drv_config_str;
+ int ret = 0;
+ LIST_HEAD(drv_config_list);
+
+ /*
+ * No point in going further if the PMU driver doesn't support
+ * cmd line configuration.
+ */
+ if (!has_drv_config(event))
+ return -EINVAL;
+
+ /* Get a handle on user specified configuration */
+ drv_config_str = strndup_user(arg, PAGE_SIZE);
+ if (IS_ERR(drv_config_str))
+ return PTR_ERR(drv_config_str);
+
+ /* Make sure we have the right format */
+ ret = perf_event_parse_drv_config(event,
+ drv_config_str, &drv_config_list);
+ if (ret)
+ goto out;
+
+ ret = event->pmu->set_drv_configs(event, &drv_config_list);
+ if (ret)
+ goto out;
+
+out:
+ kfree(drv_config_str);
+ free_drv_config_list(&drv_config_list);
+ return ret;
+}
+
+void *perf_event_drv_configs_set(struct perf_event *event, void *drv_configs)
+{
+ unsigned long flags;
+ void *old_drv_configs;
+
+ if (!event)
+ return ERR_PTR(-EINVAL);
+
+ raw_spin_lock_irqsave(&event->hw.drv_configs_lock, flags);
+ old_drv_configs = event->hw.drv_configs;
+ event->hw.drv_configs = drv_configs;
+ raw_spin_unlock_irqrestore(&event->hw.drv_configs_lock, flags);
+
+ return old_drv_configs;
+}
+EXPORT_SYMBOL_GPL(perf_event_drv_configs_set);
+
+void *perf_event_drv_configs_get(struct perf_event *event)
+{
+ if (!event)
+ return ERR_PTR(-EINVAL);
+
+ return perf_event_drv_configs_set(event, event->hw.drv_configs);
+
+}
+EXPORT_SYMBOL_GPL(perf_event_drv_configs_get);
+
+/*
+ * hrtimer based swevent callback
+ */
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
{
enum hrtimer_restart ret = HRTIMER_RESTART;
diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index c66a485a24ac..90fbc5fd3925 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -407,6 +407,7 @@ struct perf_event_attr {
#define PERF_EVENT_IOC_ID _IOR('$', 7, __u64 *)
#define PERF_EVENT_IOC_SET_BPF _IOW('$', 8, __u32)
#define PERF_EVENT_IOC_PAUSE_OUTPUT _IOW('$', 9, __u32)
+#define PERF_EVENT_IOC_SET_DRV_CONFIGS _IOW('$', 10, char *)
enum perf_event_ioc_flags {
PERF_IOC_FLAG_GROUP = 1U << 0,
--
2.7.4
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