projects/linux·blob master · refs

40 lines · 1.5 KiB

1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0
3#
4# Patching a module, where the patched code references a vmlinux symbol which
5# needs a klp relocation.
6#
7# The kernel does not allow a module-targeted klp relocation to reference a
8# vmlinux symbol, and a symbol exported with EXPORT_SYMBOL_FOR_MODULES gets a
9# klp relocation. Put together, filing that relocation under the patched
10# module produces a patch the kernel refuses to apply to its target.
11#
12# So it goes under vmlinux instead, and is applied when the patch module loads
13# rather than when the patched module does. That is the opposite of the rule
14# for a reference to a module's symbol, which test-module-object covers; this
15# is the other branch of the same decision.
16
17. "$(dirname "$0")/../lib.sh"
18
19setup
20# The object being patched is a module ...
21build_module_pair cross_module.c klp_testmod
22
23# ... and the symbol it references belongs to vmlinux, exported in a way that
24# still requires a klp relocation.
25export_syms
26add_exports_ns vmlinux module:kvm other_mod_func
27run_diff
28
29# Filed against vmlinux, applied when the patch loads.
30assert_section __klp_relocs.vmlinux
31assert_klp_sym other_mod_func vmlinux
32
33# Not against the patched module: that is the relocation the kernel rejects.
34assert_no_section __klp_relocs.klp_testmod
35
36run_post_link
37assert_klp_rela vmlinux .text.target
38assert_no_section ".klp.rela.klp_testmod..text.target"
39
40pass "klp relocation to a vmlinux symbol filed under vmlinux, not the patched module"