From fcfb126defda3cee3f1d9460dbe9a2ccac4fbd21 Mon Sep 17 00:00:00 2001 From: Jiong Wang Date: Tue, 16 Jan 2018 16:05:19 -0800 Subject: [PATCH] bpf: add new jited info fields in bpf_dev_offload and bpf_prog_info For host JIT, there are "jited_len"/"bpf_func" fields in struct bpf_prog used by all host JIT targets to get jited image and it's length. While for offload, targets are likely to have different offload mechanisms that these info are kept in device private data fields. Therefore, BPF_OBJ_GET_INFO_BY_FD syscall needs an unified way to get JIT length and contents info for offload targets. One way is to introduce new callback to parse device private data then fill those fields in bpf_prog_info. This might be a little heavy, the other way is to add generic fields which will be initialized by all offload targets. This patch follow the second approach to introduce two new fields in struct bpf_dev_offload and teach bpf_prog_get_info_by_fd about them to fill correct jited_prog_len and jited_prog_insns in bpf_prog_info. Reviewed-by: Jakub Kicinski Signed-off-by: Jiong Wang Acked-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- include/linux/bpf.h | 2 ++ kernel/bpf/offload.c | 23 +++++++++++++++++++++++ kernel/bpf/syscall.c | 31 ++++++++++++++++++------------- 3 files changed, 43 insertions(+), 13 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 5c2c104dc2c5..025b1c2f8053 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -234,6 +234,8 @@ struct bpf_prog_offload { struct list_head offloads; bool dev_state; const struct bpf_prog_offload_ops *dev_ops; + void *jited_image; + u32 jited_len; }; struct bpf_prog_aux { diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c index a88cebf368bf..6c0baa1cf8f8 100644 --- a/kernel/bpf/offload.c +++ b/kernel/bpf/offload.c @@ -230,9 +230,12 @@ int bpf_prog_offload_info_fill(struct bpf_prog_info *info, .prog = prog, .info = info, }; + struct bpf_prog_aux *aux = prog->aux; struct inode *ns_inode; struct path ns_path; + char __user *uinsns; void *res; + u32 ulen; res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args); if (IS_ERR(res)) { @@ -241,6 +244,26 @@ int bpf_prog_offload_info_fill(struct bpf_prog_info *info, return PTR_ERR(res); } + down_read(&bpf_devs_lock); + + if (!aux->offload) { + up_read(&bpf_devs_lock); + return -ENODEV; + } + + ulen = info->jited_prog_len; + info->jited_prog_len = aux->offload->jited_len; + if (info->jited_prog_len & ulen) { + uinsns = u64_to_user_ptr(info->jited_prog_insns); + ulen = min_t(u32, info->jited_prog_len, ulen); + if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) { + up_read(&bpf_devs_lock); + return -EFAULT; + } + } + + up_read(&bpf_devs_lock); + ns_inode = ns_path.dentry->d_inode; info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); info->netns_ino = ns_inode->i_ino; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c691b9e972e3..c28524483bf4 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1724,19 +1724,6 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, goto done; } - ulen = info.jited_prog_len; - info.jited_prog_len = prog->jited_len; - if (info.jited_prog_len && ulen) { - if (bpf_dump_raw_ok()) { - uinsns = u64_to_user_ptr(info.jited_prog_insns); - ulen = min_t(u32, info.jited_prog_len, ulen); - if (copy_to_user(uinsns, prog->bpf_func, ulen)) - return -EFAULT; - } else { - info.jited_prog_insns = 0; - } - } - ulen = info.xlated_prog_len; info.xlated_prog_len = bpf_prog_insn_size(prog); if (info.xlated_prog_len && ulen) { @@ -1762,6 +1749,24 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, err = bpf_prog_offload_info_fill(&info, prog); if (err) return err; + goto done; + } + + /* NOTE: the following code is supposed to be skipped for offload. + * bpf_prog_offload_info_fill() is the place to fill similar fields + * for offload. + */ + ulen = info.jited_prog_len; + info.jited_prog_len = prog->jited_len; + if (info.jited_prog_len && ulen) { + if (bpf_dump_raw_ok()) { + uinsns = u64_to_user_ptr(info.jited_prog_insns); + ulen = min_t(u32, info.jited_prog_len, ulen); + if (copy_to_user(uinsns, prog->bpf_func, ulen)) + return -EFAULT; + } else { + info.jited_prog_insns = 0; + } } done: