tracing, perf: Implement BPF programs attached to kprobes

[deliverable/linux.git] / kernel / events / core.c

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c40c2cac2d8e3eaf8106d8746aa83bb72e5899e5..5c13862d3e855512d40b9234d78b04ce0a7ec35e 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -42,6 +42,8 @@
 #include <linux/module.h>
 #include <linux/mman.h>
 #include <linux/compat.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
 
 #include "internal.h"
 
@@ -3407,6 +3409,7 @@ errout:
 }
 
 static void perf_event_free_filter(struct perf_event *event);
+static void perf_event_free_bpf_prog(struct perf_event *event);
 
 static void free_event_rcu(struct rcu_head *head)
 {
@@ -3416,6 +3419,7 @@ static void free_event_rcu(struct rcu_head *head)
        if (event->ns)
                put_pid_ns(event->ns);
        perf_event_free_filter(event);
+       perf_event_free_bpf_prog(event);
        kfree(event);
 }
 
@@ -3928,6 +3932,7 @@ static inline int perf_fget_light(int fd, struct fd *p)
 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 long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
 {
@@ -3981,6 +3986,9 @@ static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned lon
        case PERF_EVENT_IOC_SET_FILTER:
                return perf_event_set_filter(event, (void __user *)arg);
 
+       case PERF_EVENT_IOC_SET_BPF:
+               return perf_event_set_bpf_prog(event, arg);
+
        default:
                return -ENOTTY;
        }
@@ -6455,6 +6463,49 @@ static void perf_event_free_filter(struct perf_event *event)
        ftrace_profile_free_filter(event);
 }
 
+static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
+{
+       struct bpf_prog *prog;
+
+       if (event->attr.type != PERF_TYPE_TRACEPOINT)
+               return -EINVAL;
+
+       if (event->tp_event->prog)
+               return -EEXIST;
+
+       if (!(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
+               /* bpf programs can only be attached to kprobes */
+               return -EINVAL;
+
+       prog = bpf_prog_get(prog_fd);
+       if (IS_ERR(prog))
+               return PTR_ERR(prog);
+
+       if (prog->aux->prog_type != BPF_PROG_TYPE_KPROBE) {
+               /* valid fd, but invalid bpf program type */
+               bpf_prog_put(prog);
+               return -EINVAL;
+       }
+
+       event->tp_event->prog = prog;
+
+       return 0;
+}
+
+static void perf_event_free_bpf_prog(struct perf_event *event)
+{
+       struct bpf_prog *prog;
+
+       if (!event->tp_event)
+               return;
+
+       prog = event->tp_event->prog;
+       if (prog) {
+               event->tp_event->prog = NULL;
+               bpf_prog_put(prog);
+       }
+}
+
 #else
 
 static inline void perf_tp_register(void)
@@ -6470,6 +6521,14 @@ static void perf_event_free_filter(struct perf_event *event)
 {
 }
 
+static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
+{
+       return -ENOENT;
+}
+
+static void perf_event_free_bpf_prog(struct perf_event *event)
+{
+}
 #endif /* CONFIG_EVENT_TRACING */
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT