bpf: introduce BPF_RAW_TRACEPOINT

[linux-2.6-block.git] / kernel / bpf / syscall.c

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 77d45bd9f5072403b471e136e28e4c8e65b0417c..95ca2523fa6e8f17d281a8eae01d59d3b16c5cac 100644 (file)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1315,6 +1315,81 @@ static int bpf_obj_get(const union bpf_attr *attr)
                                attr->file_flags);
 }
 
+struct bpf_raw_tracepoint {
+       struct bpf_raw_event_map *btp;
+       struct bpf_prog *prog;
+};
+
+static int bpf_raw_tracepoint_release(struct inode *inode, struct file *filp)
+{
+       struct bpf_raw_tracepoint *raw_tp = filp->private_data;
+
+       if (raw_tp->prog) {
+               bpf_probe_unregister(raw_tp->btp, raw_tp->prog);
+               bpf_prog_put(raw_tp->prog);
+       }
+       kfree(raw_tp);
+       return 0;
+}
+
+static const struct file_operations bpf_raw_tp_fops = {
+       .release        = bpf_raw_tracepoint_release,
+       .read           = bpf_dummy_read,
+       .write          = bpf_dummy_write,
+};
+
+#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
+
+static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
+{
+       struct bpf_raw_tracepoint *raw_tp;
+       struct bpf_raw_event_map *btp;
+       struct bpf_prog *prog;
+       char tp_name[128];
+       int tp_fd, err;
+
+       if (strncpy_from_user(tp_name, u64_to_user_ptr(attr->raw_tracepoint.name),
+                             sizeof(tp_name) - 1) < 0)
+               return -EFAULT;
+       tp_name[sizeof(tp_name) - 1] = 0;
+
+       btp = bpf_find_raw_tracepoint(tp_name);
+       if (!btp)
+               return -ENOENT;
+
+       raw_tp = kzalloc(sizeof(*raw_tp), GFP_USER);
+       if (!raw_tp)
+               return -ENOMEM;
+       raw_tp->btp = btp;
+
+       prog = bpf_prog_get_type(attr->raw_tracepoint.prog_fd,
+                                BPF_PROG_TYPE_RAW_TRACEPOINT);
+       if (IS_ERR(prog)) {
+               err = PTR_ERR(prog);
+               goto out_free_tp;
+       }
+
+       err = bpf_probe_register(raw_tp->btp, prog);
+       if (err)
+               goto out_put_prog;
+
+       raw_tp->prog = prog;
+       tp_fd = anon_inode_getfd("bpf-raw-tracepoint", &bpf_raw_tp_fops, raw_tp,
+                                O_CLOEXEC);
+       if (tp_fd < 0) {
+               bpf_probe_unregister(raw_tp->btp, prog);
+               err = tp_fd;
+               goto out_put_prog;
+       }
+       return tp_fd;
+
+out_put_prog:
+       bpf_prog_put(prog);
+out_free_tp:
+       kfree(raw_tp);
+       return err;
+}
+
 #ifdef CONFIG_CGROUP_BPF
 
 #define BPF_PROG_ATTACH_LAST_FIELD attach_flags
@@ -1925,6 +2000,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
        case BPF_OBJ_GET_INFO_BY_FD:
                err = bpf_obj_get_info_by_fd(&attr, uattr);
                break;
+       case BPF_RAW_TRACEPOINT_OPEN:
+               err = bpf_raw_tracepoint_open(&attr);
+               break;
        default:
                err = -EINVAL;
                break;