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 <[email protected]> --- 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
