Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751734AbbGaMAB (ORCPT ); Fri, 31 Jul 2015 08:00:01 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:49508 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751473AbbGaL75 (ORCPT ); Fri, 31 Jul 2015 07:59:57 -0400 From: Kaixu Xia To: , , , , , , , CC: , , , , , Subject: [PATCH v5 2/4] bpf: Add new bpf map type to store the pointer to struct perf_event Date: Fri, 31 Jul 2015 11:59:28 +0000 Message-ID: <1438343970-11974-3-git-send-email-xiakaixu@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1438343970-11974-1-git-send-email-xiakaixu@huawei.com> References: <1438343970-11974-1-git-send-email-xiakaixu@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.193.250] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.55BB6339.002A,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 345b03d898e19e8165eef389201db2fe Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4992 Lines: 157 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 --- include/linux/bpf.h | 1 + include/linux/perf_event.h | 2 ++ include/uapi/linux/bpf.h | 1 + kernel/bpf/arraymap.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++ kernel/events/core.c | 17 ++++++++++++++ 5 files changed, 76 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a8ce262..d0b394a 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/linux/perf_event.h b/include/linux/perf_event.h index 2027809..27e05c1 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -641,6 +641,7 @@ extern int perf_event_init_task(struct task_struct *child); extern void perf_event_exit_task(struct task_struct *child); extern void perf_event_free_task(struct task_struct *task); extern void perf_event_delayed_put(struct task_struct *task); +extern struct perf_event *perf_event_get(unsigned int fd); extern void perf_event_print_debug(void); extern void perf_pmu_disable(struct pmu *pmu); extern void perf_pmu_enable(struct pmu *pmu); @@ -979,6 +980,7 @@ static inline int perf_event_init_task(struct task_struct *child) { return 0; } static inline void perf_event_exit_task(struct task_struct *child) { } static inline void perf_event_free_task(struct task_struct *task) { } static inline void perf_event_delayed_put(struct task_struct *task) { } +static struct perf_event *perf_event_get(unsigned int fd) { return ERR_PTR(-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/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 29ef6f9..69a1f6b 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 45df657..b7e0b5d 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -273,3 +273,58 @@ 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; + + event = perf_event_get(fd); + if (IS_ERR(event)) + return event; + + /* + * prevent some crazy events so we can make our life easier + */ + if (event->attr.type != PERF_TYPE_RAW && + event->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); diff --git a/kernel/events/core.c b/kernel/events/core.c index d3dae34..58f0d47 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8574,6 +8574,23 @@ void perf_event_delayed_put(struct task_struct *task) WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); } +struct perf_event *perf_event_get(unsigned int fd) +{ + int err; + struct fd f; + struct perf_event *event; + + err = perf_fget_light(fd, &f); + if (err) + return ERR_PTR(err); + + event = f.file->private_data; + atomic_long_inc(&event->refcount); + fdput(f); + + return event; +} + /* * inherit a event from parent task to child task: */ -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/