livepatch: handle ancient compilers with more grace
We are aborting a build in case when gcc doesn't support fentry on x86_64
(regs->ip modification can't really reliably work with mcount).
This however breaks allmodconfig for people with older gccs that don't
support -mfentry.
Turn the build-time failure into runtime failure, resulting in the whole
infrastructure not being initialized if CC_USING_FENTRY is unset.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 6f63879..ce42d3b 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -911,6 +911,12 @@
{
int ret;
+ ret = klp_check_compiler_support();
+ if (ret) {
+ pr_info("Your compiler is too old; turning off.\n");
+ return -EINVAL;
+ }
+
ret = register_module_notifier(&klp_module_nb);
if (ret)
return ret;