linux-kernel - [PATCH v2 2/5] x86/mce/inject: Warn the user on a not set valid bit in MCA

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Date:   Tue, 19 Oct 2021 18:36:38 -0500
From:   Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
To:     <x86@...nel.org>, <linux-edac@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC:     Tony Luck <tony.luck@...el.com>, "H . Peter Anvin" <hpa@...or.com>,
        <yazen.ghannam@....com>, <Smita.KoralahalliChannabasappa@....com>
Subject: [PATCH v2 2/5] x86/mce/inject: Warn the user on a not set valid bit in MCA_STATUS

MCA handlers check the valid bit in each status register (MCA_STATUS[Val])
and will likely ignore signatures if the valid bit is not set.

Warn the user if the valid bit is not set before doing error injection.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
---
v2:
	Added a warning statement instead of setting the valid bit.
---
 arch/x86/kernel/cpu/mce/inject.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
index 601efd104bb4..a993dc3d0333 100644
--- a/arch/x86/kernel/cpu/mce/inject.c
+++ b/arch/x86/kernel/cpu/mce/inject.c
@@ -487,6 +487,9 @@ static void do_inject(void)
 
 	i_mce.tsc = rdtsc_ordered();
 
+	if (!(i_mce.status & MCI_STATUS_VAL))
+		pr_warn("Handlers might ignore signatures with Val=0 in MCA_STATUS\n");
+
 	if (i_mce.misc)
 		i_mce.status |= MCI_STATUS_MISCV;
 
-- 
2.17.1