From: Borislav Petkov <bp@suse.de>
Date: Mon, 1 Nov 2021 16:43:33 +0100
Subject: x86/mce: Mark mce_end() noinstr
Git-commit: b4813539d37fa31fed62cdfab7bd2dd8929c5b2e
Patch-mainline: 5.17-rc1
References: git-fixes

It is called by the #MC handler which is noinstr.

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xbd6: call to memset() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-9-bp@alien8.de
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 arch/x86/kernel/cpu/mce/core.c |   14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1063,10 +1063,13 @@ static int mce_start(int *no_way_out)
  * Synchronize between CPUs after main scanning loop.
  * This invokes the bulk of the Monarch processing.
  */
-static int mce_end(int order)
+static noinstr int mce_end(int order)
 {
-	int ret = -1;
 	u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC;
+	int ret = -1;
+
+	/* Allow instrumentation around external facilities. */
+	instrumentation_begin();
 
 	if (!timeout)
 		goto reset;
@@ -1110,7 +1113,8 @@ static int mce_end(int order)
 		/*
 		 * Don't reset anything. That's done by the Monarch.
 		 */
-		return 0;
+		ret = 0;
+		goto out;
 	}
 
 	/*
@@ -1126,6 +1130,10 @@ reset:
 	 * Let others run again.
 	 */
 	atomic_set(&mce_executing, 0);
+
+out:
+	instrumentation_end();
+
 	return ret;
 }