From ea317b267e9d03a8241893aa176fba7661d07579 Mon Sep 17 00:00:00 2001 From: Kaixu Xia Date: Thu, 6 Aug 2015 07:02:34 +0000 Subject: [PATCH] bpf: Add new bpf map type to store the pointer to struct perf_event Introduce a new bpf map type 'BPF_MAP_TYPE_PERF_EVENT_ARRAY'. This map only stores the pointer to struct perf_event. The user space event FDs from perf_event_open() syscall are converted to the pointer to struct perf_event and stored in map. Signed-off-by: Kaixu Xia Signed-off-by: David S. Miller --- include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 1 + kernel/bpf/arraymap.c | 57 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 59 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index d495211d63d1..4fc1f4070789 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -10,6 +10,7 @@ #include #include #include +#include struct bpf_map; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 2ce13c109b00..a1814e8e53a7 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -114,6 +114,7 @@ enum bpf_map_type { BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PROG_ARRAY, + BPF_MAP_TYPE_PERF_EVENT_ARRAY, }; enum bpf_prog_type { diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 45df6572ecfd..29ace107f236 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -273,3 +273,60 @@ static int __init register_prog_array_map(void) return 0; } late_initcall(register_prog_array_map); + +static void perf_event_array_map_free(struct bpf_map *map) +{ + bpf_fd_array_map_clear(map); + fd_array_map_free(map); +} + +static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd) +{ + struct perf_event *event; + const struct perf_event_attr *attr; + + event = perf_event_get(fd); + if (IS_ERR(event)) + return event; + + attr = perf_event_attrs(event); + if (IS_ERR(attr)) + return (void *)attr; + + if (attr->type != PERF_TYPE_RAW && + attr->type != PERF_TYPE_HARDWARE) { + perf_event_release_kernel(event); + return ERR_PTR(-EINVAL); + } + return event; +} + +static void perf_event_fd_array_put_ptr(void *ptr) +{ + struct perf_event *event = ptr; + + perf_event_release_kernel(event); +} + +static const struct bpf_map_ops perf_event_array_ops = { + .map_alloc = fd_array_map_alloc, + .map_free = perf_event_array_map_free, + .map_get_next_key = array_map_get_next_key, + .map_lookup_elem = fd_array_map_lookup_elem, + .map_update_elem = fd_array_map_update_elem, + .map_delete_elem = fd_array_map_delete_elem, + .map_fd_get_ptr = perf_event_fd_array_get_ptr, + .map_fd_put_ptr = perf_event_fd_array_put_ptr, +}; + +static struct bpf_map_type_list perf_event_array_type __read_mostly = { + .ops = &perf_event_array_ops, + .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, +}; + +static int __init register_perf_event_array_map(void) +{ + bpf_register_map_type(&perf_event_array_type); + return 0; +} +late_initcall(register_perf_event_array_map); -- 2.20.1