From f91840a32deef5cb1bf73338bc5010f843b01426 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Fri, 2 Jun 2017 21:03:52 -0700 Subject: [PATCH] perf, bpf: Add BPF support to all perf_event types Allow BPF_PROG_TYPE_PERF_EVENT program types to attach to all perf_event types, including HW_CACHE, RAW, and dynamic pmu events. Only tracepoint/kprobe events are treated differently which require BPF_PROG_TYPE_TRACEPOINT/BPF_PROG_TYPE_KPROBE program types accordingly. Also add support for reading all event counters using bpf_perf_event_read() helper. Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/perf_event.h | 7 ++++-- kernel/bpf/arraymap.c | 28 ++++++----------------- kernel/events/core.c | 47 +++++++++++++++++++++++--------------- kernel/trace/bpf_trace.c | 22 +++++++----------- 4 files changed, 48 insertions(+), 56 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 24a635887f28..8fc5f0fada5e 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -896,7 +896,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, void *context); extern void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu); -extern u64 perf_event_read_local(struct perf_event *event); +int perf_event_read_local(struct perf_event *event, u64 *value); extern u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running); @@ -1301,7 +1301,10 @@ static inline const struct perf_event_attr *perf_event_attrs(struct perf_event * { return ERR_PTR(-EINVAL); } -static inline u64 perf_event_read_local(struct perf_event *event) { return -EINVAL; } +static inline int perf_event_read_local(struct perf_event *event, u64 *value) +{ + return -EINVAL; +} static inline void perf_event_print_debug(void) { } static inline int perf_event_task_disable(void) { return -EINVAL; } static inline int perf_event_task_enable(void) { return -EINVAL; } diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 172dc8ee0e3b..ecb43542246e 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -452,38 +452,24 @@ static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee) static void *perf_event_fd_array_get_ptr(struct bpf_map *map, struct file *map_file, int fd) { - const struct perf_event_attr *attr; struct bpf_event_entry *ee; struct perf_event *event; struct file *perf_file; + u64 value; perf_file = perf_event_get(fd); if (IS_ERR(perf_file)) return perf_file; + ee = ERR_PTR(-EOPNOTSUPP); event = perf_file->private_data; - ee = ERR_PTR(-EINVAL); - - attr = perf_event_attrs(event); - if (IS_ERR(attr) || attr->inherit) + if (perf_event_read_local(event, &value) == -EOPNOTSUPP) goto err_out; - switch (attr->type) { - case PERF_TYPE_SOFTWARE: - if (attr->config != PERF_COUNT_SW_BPF_OUTPUT) - goto err_out; - /* fall-through */ - case PERF_TYPE_RAW: - case PERF_TYPE_HARDWARE: - ee = bpf_event_entry_gen(perf_file, map_file); - if (ee) - return ee; - ee = ERR_PTR(-ENOMEM); - /* fall-through */ - default: - break; - } - + ee = bpf_event_entry_gen(perf_file, map_file); + if (ee) + return ee; + ee = ERR_PTR(-ENOMEM); err_out: fput(perf_file); return ee; diff --git a/kernel/events/core.c b/kernel/events/core.c index 6e75a5c9412d..51e40e4876c0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3636,10 +3636,10 @@ static inline u64 perf_event_count(struct perf_event *event) * will not be local and we cannot read them atomically * - must not have a pmu::count method */ -u64 perf_event_read_local(struct perf_event *event) +int perf_event_read_local(struct perf_event *event, u64 *value) { unsigned long flags; - u64 val; + int ret = 0; /* * Disabling interrupts avoids all counter scheduling (context @@ -3647,25 +3647,37 @@ u64 perf_event_read_local(struct perf_event *event) */ local_irq_save(flags); - /* If this is a per-task event, it must be for current */ - WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) && - event->hw.target != current); - - /* If this is a per-CPU event, it must be for this CPU */ - WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) && - event->cpu != smp_processor_id()); - /* * It must not be an event with inherit set, we cannot read * all child counters from atomic context. */ - WARN_ON_ONCE(event->attr.inherit); + if (event->attr.inherit) { + ret = -EOPNOTSUPP; + goto out; + } /* * It must not have a pmu::count method, those are not * NMI safe. */ - WARN_ON_ONCE(event->pmu->count); + if (event->pmu->count) { + ret = -EOPNOTSUPP; + goto out; + } + + /* If this is a per-task event, it must be for current */ + if ((event->attach_state & PERF_ATTACH_TASK) && + event->hw.target != current) { + ret = -EINVAL; + goto out; + } + + /* If this is a per-CPU event, it must be for this CPU */ + if (!(event->attach_state & PERF_ATTACH_TASK) && + event->cpu != smp_processor_id()) { + ret = -EINVAL; + goto out; + } /* * If the event is currently on this CPU, its either a per-task event, @@ -3675,10 +3687,11 @@ u64 perf_event_read_local(struct perf_event *event) if (event->oncpu == smp_processor_id()) event->pmu->read(event); - val = local64_read(&event->count); + *value = local64_read(&event->count); +out: local_irq_restore(flags); - return val; + return ret; } static int perf_event_read(struct perf_event *event, bool group) @@ -8037,12 +8050,8 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) bool is_kprobe, is_tracepoint; struct bpf_prog *prog; - if (event->attr.type == PERF_TYPE_HARDWARE || - event->attr.type == PERF_TYPE_SOFTWARE) - return perf_event_set_bpf_handler(event, prog_fd); - if (event->attr.type != PERF_TYPE_TRACEPOINT) - return -EINVAL; + return perf_event_set_bpf_handler(event, prog_fd); if (event->tp_event->prog) return -EEXIST; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 460a031c77e5..08eb072430b9 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -234,7 +234,8 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) unsigned int cpu = smp_processor_id(); u64 index = flags & BPF_F_INDEX_MASK; struct bpf_event_entry *ee; - struct perf_event *event; + u64 value = 0; + int err; if (unlikely(flags & ~(BPF_F_INDEX_MASK))) return -EINVAL; @@ -247,21 +248,14 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) if (!ee) return -ENOENT; - event = ee->event; - if (unlikely(event->attr.type != PERF_TYPE_HARDWARE && - event->attr.type != PERF_TYPE_RAW)) - return -EINVAL; - - /* make sure event is local and doesn't have pmu::count */ - if (unlikely(event->oncpu != cpu || event->pmu->count)) - return -EINVAL; - + err = perf_event_read_local(ee->event, &value); /* - * we don't know if the function is run successfully by the - * return value. It can be judged in other places, such as - * eBPF programs. + * this api is ugly since we miss [-22..-2] range of valid + * counter values, but that's uapi */ - return perf_event_read_local(event); + if (err) + return err; + return value; } static const struct bpf_func_proto bpf_perf_event_read_proto = { -- 2.39.5