linux-kernel - [PATCH v1 08/12] x86/mce: Mark mce

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Message-Id: <20211208111343.8130-9-bp@alien8.de>
Date:   Wed,  8 Dec 2021 12:13:39 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Tony Luck <tony.luck@...el.com>
Cc:     X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH v1 08/12] x86/mce: Mark mce_end() noinstr

From: Borislav Petkov <bp@...e.de>

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@...e.de>
---
 arch/x86/kernel/cpu/mce/core.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index d81266885de3..e86334925797 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1064,10 +1064,13 @@ 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;
@@ -1108,7 +1111,8 @@ static int mce_end(int order)
 		/*
 		 * Don't reset anything. That's done by the Monarch.
 		 */
-		return 0;
+		ret = 0;
+		goto out;
 	}
 
 	/*
@@ -1124,6 +1128,10 @@ static int mce_end(int order)
 	 * Let others run again.
 	 */
 	atomic_set(&mce_executing, 0);
+
+out:
+	instrumentation_end();
+
 	return ret;
 }
 
-- 
2.29.2