[PATCH v0 07/12] x86/mce: Mark mce_panic() noinstr

Borislav Petkov
2021-11-04T14:41:05Z

And allow instrumentation inside it because it does calls to other
facilities which will not be tagged noinstr.

Fixes

vmlinux.o: warning: objtool: do_machine_check()+0xc73: call to mce_panic() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/cpu/mce/core.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 65a8be420aff..4783b009f5aa 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -267,11 +267,13 @@ static void wait_for_panic(void)
panic("Panicing machine check CPU died");
}

-static void mce_panic(const char *msg, struct mce *final, char *exp)
+static noinstr void mce_panic(const char *msg, struct mce *final, char *exp)
{
- int apei_err = 0;
struct llist_node *pending;
struct mce_evt_llist *l;
+ int apei_err = 0;
+
+ instrumentation_begin();

if (!fake_panic) {
/*
@@ -286,7 +288,7 @@ static void mce_panic(const char *msg, struct mce *final, char *exp)
} else {
/* Don't log too much for fake panic */
if (atomic_inc_return(&mce_fake_panicked) > 1)
- return;
+ goto out;
}
pending = mce_gen_pool_prepare_records();
/* First print corrected ones that are still unlogged */
@@ -324,6 +326,9 @@ static void mce_panic(const char *msg, struct mce *final, char *exp)
panic(msg);
} else
pr_emerg(HW_ERR "Fake kernel panic: %s\n", msg);
+
+out:
+ instrumentation_end();
}

/* Support code for software error injection */
--
2.29.2