Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 815581c1 authored by Sandipan Das's avatar Sandipan Das Committed by Daniel Borkmann
Browse files

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: default avatarSandipan Das <sandipan@linux.vnet.ibm.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 4d56a76e

include/uapi/linux/bpf.h

+2 −0
Original line number Diff line number Diff line
@@ -2206,7 +2206,9 @@ struct bpf_prog_info { 
	__u64 netns_dev;

	__u64 netns_ino;

	__u32 nr_jited_ksyms;

	__u32 nr_jited_func_lens;

	__aligned_u64 jited_ksyms;

	__aligned_u64 jited_func_lens;

} __attribute__((aligned(8)));



struct bpf_map_info {

kernel/bpf/syscall.c

+20 −0
Original line number Diff line number Diff line
@@ -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))