linux - tools/objtool/tests/generic/test-post-link.sh

42 lines · 1.6 KiB

1	#!/bin/bash
2	# SPDX-License-Identifier: GPL-2.0
3	#
4	# klp post-link converts the intermediate __klp_relocs.* sections into the
5	# .klp.rela.* form the kernel applies at patch load. Getting this wrong is
6	# invisible at build time: the module links and loads, and the relocations are
7	# simply never applied.
8
9	. "$(dirname "$0")/../lib.sh"
10
11	setup
12	build_pair static_local.c
13
14	# An unexported symbol is what produces a klp relocation in the first place.
15	# The static local is renamed by the compiler -- counter.0 with gcc -- so the
16	# fixture's premise is that some local of that shape exists, not that a symbol
17	# called "counter" does. Find it first; everything below names it.
18	local_sym="$(in_symbols orig.o \|
19	awk '$4 == "OBJECT" && $5 == "LOCAL" && $8 ~ /counter/ { print $8; exit }')"
20	[ -n "$local_sym" ] \|\| fail "fixture produced no local 'counter' symbol"
21
22	run_diff
23	assert_section __klp_relocs.vmlinux
24
25	# Nothing has converted them yet.
26	assert_no_section ".klp.rela.vmlinux..text.target"
27
28	# The original relocation is neutralised by pointing it at a tombstone, which
29	# is what stops the module loader resolving it behind livepatch's back.
30	#
31	# Compilers mangle a static local differently -- gcc says counter.0, clang
32	# target.counter -- so find what this one produced rather than assuming.
33	assert_tombstone "$local_sym"
34
35	run_post_link
36
37	# One .klp.rela section per base section, carrying SHF_RELA_LIVEPATCH, against
38	# a symbol in SHN_LIVEPATCH for the kernel to resolve.
39	assert_klp_rela vmlinux .text.target
40	assert_livepatch_sym "$local_sym"
41
42	pass "klp relocations converted to .klp.rela with SHN_LIVEPATCH symbols"