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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Borislav Petkov <bp@suse.de>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0643/1039] x86/mce: Mark mce_end() noinstr
Date:   Mon, 24 Jan 2022 19:40:32 +0100
Message-Id: <20220124184146.973490807@linuxfoundation.org>
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From: Borislav Petkov <bp@suse.de>

[ Upstream commit b4813539d37fa31fed62cdfab7bd2dd8929c5b2e ]

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: Sasha Levin <sashal@kernel.org>
---
 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 9a52ec55e0555..75095986e5eff 100644
--- 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;
 }
 
-- 
2.34.1