[PATCH v3 1/2] objtool: Add --Werror

Brendan Jackman
2025-01-13T14:05:21Z

At present objtool only prints to the terminal when observing "fatal
warnings". This option lets you have it produce an error instead.

The use case for this is noinstr validation; so far I've never seen any
false warnings here, but it quite often detects real bugs. It would
be useful for the build to fail when I have those bugs.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
tools/objtool/builtin-check.c | 6 ++++++
tools/objtool/check.c | 7 ++-----
tools/objtool/include/objtool/builtin.h | 1 +
3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 387d56a7f5fb8da8435d0a3f5c05eeee66932c9b..0b28082df90710ff7127327deb857c0548f378c7 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -94,6 +94,12 @@ static const struct option check_options[] = {
OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
+ /*
+ * For now, don't fail the kernel build on fatal warnings by default.
+ * These errors are still fairly common due to the growing matrix of
+ * supported toolchains and their recent pace of change.
+ */
+ OPT_BOOLEAN(0, "Werror", &opts.werror, "fail on fatal warnings"),

OPT_END(),
};
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 76060da755b5c51cda3a669d8245d7d004e25f22..e44135293eb45f908e00359d84d954cfeddd266f 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -4944,10 +4944,7 @@ int check(struct objtool_file *file)
}

out:
- /*
- * For now, don't fail the kernel build on fatal warnings. These
- * errors are still fairly common due to the growing matrix of
- * supported toolchains and their recent pace of change.
- */
+ if (opts.werror && warnings)
+ return 1;
return 0;
}
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index fcca6662c8b4b5e0048e54fada8694cc2e6ebc34..97d668010efadfa05bb6e25e1967a7d72bf77815 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -38,6 +38,7 @@ struct opts {
bool sec_address;
bool stats;
bool verbose;
+ bool werror;
};

extern struct opts opts;

--
2.47.1.613.gc27f4b7a9f-goog