diff options
Diffstat (limited to 'kernel/bpf/syscall.c')
-rw-r--r-- | kernel/bpf/syscall.c | 223 |
1 files changed, 181 insertions, 42 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c536c65256ad..13de65363ba2 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2173,24 +2173,154 @@ static int bpf_obj_get(const union bpf_attr *attr) attr->file_flags); } -static int bpf_tracing_prog_release(struct inode *inode, struct file *filp) +struct bpf_link { + atomic64_t refcnt; + const struct bpf_link_ops *ops; + struct bpf_prog *prog; + struct work_struct work; +}; + +void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops, + struct bpf_prog *prog) { - struct bpf_prog *prog = filp->private_data; + atomic64_set(&link->refcnt, 1); + link->ops = ops; + link->prog = prog; +} + +void bpf_link_inc(struct bpf_link *link) +{ + atomic64_inc(&link->refcnt); +} + +/* bpf_link_free is guaranteed to be called from process context */ +static void bpf_link_free(struct bpf_link *link) +{ + struct bpf_prog *prog; - WARN_ON_ONCE(bpf_trampoline_unlink_prog(prog)); + /* remember prog locally, because release below will free link memory */ + prog = link->prog; + /* extra clean up and kfree of container link struct */ + link->ops->release(link); + /* no more accesing of link members after this point */ bpf_prog_put(prog); +} + +static void bpf_link_put_deferred(struct work_struct *work) +{ + struct bpf_link *link = container_of(work, struct bpf_link, work); + + bpf_link_free(link); +} + +/* bpf_link_put can be called from atomic context, but ensures that resources + * are freed from process context + */ +void bpf_link_put(struct bpf_link *link) +{ + if (!atomic64_dec_and_test(&link->refcnt)) + return; + + if (in_atomic()) { + INIT_WORK(&link->work, bpf_link_put_deferred); + schedule_work(&link->work); + } else { + bpf_link_free(link); + } +} + +static int bpf_link_release(struct inode *inode, struct file *filp) +{ + struct bpf_link *link = filp->private_data; + + bpf_link_put(link); return 0; } -static const struct file_operations bpf_tracing_prog_fops = { - .release = bpf_tracing_prog_release, +#ifdef CONFIG_PROC_FS +static const struct bpf_link_ops bpf_raw_tp_lops; +static const struct bpf_link_ops bpf_tracing_link_lops; +static const struct bpf_link_ops bpf_xdp_link_lops; + +static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp) +{ + const struct bpf_link *link = filp->private_data; + const struct bpf_prog *prog = link->prog; + char prog_tag[sizeof(prog->tag) * 2 + 1] = { }; + const char *link_type; + + if (link->ops == &bpf_raw_tp_lops) + link_type = "raw_tracepoint"; + else if (link->ops == &bpf_tracing_link_lops) + link_type = "tracing"; + else + link_type = "unknown"; + + bin2hex(prog_tag, prog->tag, sizeof(prog->tag)); + seq_printf(m, + "link_type:\t%s\n" + "prog_tag:\t%s\n" + "prog_id:\t%u\n", + link_type, + prog_tag, + prog->aux->id); +} +#endif + +const struct file_operations bpf_link_fops = { +#ifdef CONFIG_PROC_FS + .show_fdinfo = bpf_link_show_fdinfo, +#endif + .release = bpf_link_release, .read = bpf_dummy_read, .write = bpf_dummy_write, }; +int bpf_link_new_fd(struct bpf_link *link) +{ + return anon_inode_getfd("bpf-link", &bpf_link_fops, link, O_CLOEXEC); +} + +struct bpf_link *bpf_link_get_from_fd(u32 ufd) +{ + struct fd f = fdget(ufd); + struct bpf_link *link; + + if (!f.file) + return ERR_PTR(-EBADF); + if (f.file->f_op != &bpf_link_fops) { + fdput(f); + return ERR_PTR(-EINVAL); + } + + link = f.file->private_data; + bpf_link_inc(link); + fdput(f); + + return link; +} + +struct bpf_tracing_link { + struct bpf_link link; +}; + +static void bpf_tracing_link_release(struct bpf_link *link) +{ + struct bpf_tracing_link *tr_link = + container_of(link, struct bpf_tracing_link, link); + + WARN_ON_ONCE(bpf_trampoline_unlink_prog(link->prog)); + kfree(tr_link); +} + +static const struct bpf_link_ops bpf_tracing_link_lops = { + .release = bpf_tracing_link_release, +}; + static int bpf_tracing_prog_attach(struct bpf_prog *prog) { - int tr_fd, err; + struct bpf_tracing_link *link; + int link_fd, err; if (prog->expected_attach_type != BPF_TRACE_FENTRY && prog->expected_attach_type != BPF_TRACE_FEXIT && @@ -2199,58 +2329,61 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog) goto out_put_prog; } + link = kzalloc(sizeof(*link), GFP_USER); + if (!link) { + err = -ENOMEM; + goto out_put_prog; + } + bpf_link_init(&link->link, &bpf_tracing_link_lops, prog); + err = bpf_trampoline_link_prog(prog); if (err) - goto out_put_prog; + goto out_free_link; - tr_fd = anon_inode_getfd("bpf-tracing-prog", &bpf_tracing_prog_fops, - prog, O_CLOEXEC); - if (tr_fd < 0) { + link_fd = bpf_link_new_fd(&link->link); + if (link_fd < 0) { WARN_ON_ONCE(bpf_trampoline_unlink_prog(prog)); - err = tr_fd; - goto out_put_prog; + err = link_fd; + goto out_free_link; } - return tr_fd; + return link_fd; +out_free_link: + kfree(link); out_put_prog: bpf_prog_put(prog); return err; } -struct bpf_raw_tracepoint { +struct bpf_raw_tp_link { + struct bpf_link link; struct bpf_raw_event_map *btp; - struct bpf_prog *prog; }; -static int bpf_raw_tracepoint_release(struct inode *inode, struct file *filp) +static void bpf_raw_tp_link_release(struct bpf_link *link) { - struct bpf_raw_tracepoint *raw_tp = filp->private_data; + struct bpf_raw_tp_link *raw_tp = + container_of(link, struct bpf_raw_tp_link, link); - if (raw_tp->prog) { - bpf_probe_unregister(raw_tp->btp, raw_tp->prog); - bpf_prog_put(raw_tp->prog); - } + bpf_probe_unregister(raw_tp->btp, raw_tp->link.prog); bpf_put_raw_tracepoint(raw_tp->btp); 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, +static const struct bpf_link_ops bpf_raw_tp_lops = { + .release = bpf_raw_tp_link_release, }; #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_tp_link *raw_tp; struct bpf_raw_event_map *btp; struct bpf_prog *prog; const char *tp_name; char buf[128]; - int tp_fd, err; + int link_fd, err; if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN)) return -EINVAL; @@ -2302,21 +2435,20 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr) err = -ENOMEM; goto out_put_btp; } + bpf_link_init(&raw_tp->link, &bpf_raw_tp_lops, prog); raw_tp->btp = btp; - raw_tp->prog = prog; err = bpf_probe_register(raw_tp->btp, prog); if (err) goto out_free_tp; - tp_fd = anon_inode_getfd("bpf-raw-tracepoint", &bpf_raw_tp_fops, raw_tp, - O_CLOEXEC); - if (tp_fd < 0) { + link_fd = bpf_link_new_fd(&raw_tp->link); + if (link_fd < 0) { bpf_probe_unregister(raw_tp->btp, prog); - err = tp_fd; + err = link_fd; goto out_free_tp; } - return tp_fd; + return link_fd; out_free_tp: kfree(raw_tp); @@ -3266,15 +3398,21 @@ static int bpf_task_fd_query(const union bpf_attr *attr, if (err) goto out; - if (file->f_op == &bpf_raw_tp_fops) { - struct bpf_raw_tracepoint *raw_tp = file->private_data; - struct bpf_raw_event_map *btp = raw_tp->btp; + if (file->f_op == &bpf_link_fops) { + struct bpf_link *link = file->private_data; - err = bpf_task_fd_query_copy(attr, uattr, - raw_tp->prog->aux->id, - BPF_FD_TYPE_RAW_TRACEPOINT, - btp->tp->name, 0, 0); - goto put_file; + if (link->ops == &bpf_raw_tp_lops) { + struct bpf_raw_tp_link *raw_tp = + container_of(link, struct bpf_raw_tp_link, link); + struct bpf_raw_event_map *btp = raw_tp->btp; + + err = bpf_task_fd_query_copy(attr, uattr, + raw_tp->link.prog->aux->id, + BPF_FD_TYPE_RAW_TRACEPOINT, + btp->tp->name, 0, 0); + goto put_file; + } + goto out_not_supp; } event = perf_get_event(file); @@ -3294,6 +3432,7 @@ static int bpf_task_fd_query(const union bpf_attr *attr, goto put_file; } +out_not_supp: err = -ENOTSUPP; put_file: fput(file); |