From 815581c11cc29f74af252b6306ea1ec94160231a Mon Sep 17 00:00:00 2001 From: Sandipan Das Date: Thu, 24 May 2018 12:26:52 +0530 Subject: bpf: get JITed image lengths of functions via syscall This adds new two new fields to struct bpf_prog_info. For multi-function programs, these fields can be used to pass a list of the JITed image lengths of each function for a given program to userspace using the bpf system call with the BPF_OBJ_GET_INFO_BY_FD command. This can be used by userspace applications like bpftool to split up the contiguous JITed dump, also obtained via the system call, into more relatable chunks corresponding to each function. Signed-off-by: Sandipan Das Signed-off-by: Daniel Borkmann --- kernel/bpf/syscall.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c8e987a612b5..788456c18617 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2037,6 +2037,26 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, } } + ulen = info.nr_jited_func_lens; + info.nr_jited_func_lens = prog->aux->func_cnt; + if (info.nr_jited_func_lens && ulen) { + if (bpf_dump_raw_ok()) { + u32 __user *user_lens; + u32 func_len, i; + + /* copy the JITed image lengths for each function */ + ulen = min_t(u32, info.nr_jited_func_lens, ulen); + user_lens = u64_to_user_ptr(info.jited_func_lens); + for (i = 0; i < ulen; i++) { + func_len = prog->aux->func[i]->jited_len; + if (put_user(func_len, &user_lens[i])) + return -EFAULT; + } + } else { + info.jited_func_lens = 0; + } + } + done: if (copy_to_user(uinfo, &info, info_len) || put_user(info_len, &uattr->info.info_len)) -- cgit v1.2.3-59-g8ed1b