Merge branch 'bpf-dump-and-disasm-nfp-jit'

Jakub Kicinski says:

====================
Jiong says:

Currently bpftool could disassemble host jited image, for example x86_64,
using libbfd. However it couldn't disassemble offload jited image.

There are two reasons:

  1. bpf_obj_get_info_by_fd/struct bpf_prog_info couldn't get the address
     of jited image and image's length.

  2. Even after issue 1 resolved, bpftool couldn't figure out what is the
     offload arch from bpf_prog_info, therefore can't drive libbfd
     disassembler correctly.

  This patch set resolve issue 1 by introducing two new fields "jited_len"
and "jited_image" in bpf_dev_offload. These two fields serve as the generic
interface to communicate the jited image address and length for all offload
targets to higher level caller. For example, bpf_obj_get_info_by_fd could
use them to fill the userspace visible fields jited_prog_len and
jited_prog_insns.

  This patch set resolve issue 2 by getting bfd backend name through
"ifindex", i.e network interface index.

v1:
 - Deduct bfd arch name through ifindex, i.e network interface index.
   First, map ifindex to devname through ifindex_to_name_ns, then get
   pci id through /sys/class/dev/DEVNAME/device/vendor. (Daniel, Alexei)
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 18 insertions, 13 deletions

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: