linux-kernel - [tip: ras/core] x86/mce: Move machine_check_poll() status checks to helper functions

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Message-ID: <175758653917.709179.7141514378637292570.tip-bot2@tip-bot2>
Date: Thu, 11 Sep 2025 10:28:59 -0000
From: "tip-bot2 for Yazen Ghannam" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Yazen Ghannam <yazen.ghannam@....com>,
 "Borislav Petkov (AMD)" <bp@...en8.de>, Qiuxu Zhuo <qiuxu.zhuo@...el.com>,
 Tony Luck <tony.luck@...el.com>, Nikolay Borisov <nik.borisov@...e.com>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: ras/core] x86/mce: Move machine_check_poll() status checks to
 helper functions

The following commit has been merged into the ras/core branch of tip:

Commit-ID:     91af6842e9945d064401ed2d6e91539a619760d1
Gitweb:        https://git.kernel.org/tip/91af6842e9945d064401ed2d6e91539a619760d1
Author:        Yazen Ghannam <yazen.ghannam@....com>
AuthorDate:    Mon, 08 Sep 2025 15:40:35 
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Thu, 11 Sep 2025 12:23:22 +02:00

x86/mce: Move machine_check_poll() status checks to helper functions

There are a number of generic and vendor-specific status checks in
machine_check_poll(). These are used to determine if an error should be
skipped.

Move these into helper functions. Future vendor-specific checks will be
added to the helpers.

Signed-off-by: Yazen Ghannam <yazen.ghannam@....com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
Reviewed-by: Tony Luck <tony.luck@...el.com>
Reviewed-by: Nikolay Borisov <nik.borisov@...e.com>
Tested-by: Tony Luck <tony.luck@...el.com>
Link: https://lore.kernel.org/20250908-wip-mca-updates-v6-0-eef5d6c74b9c@amd.com
---
 arch/x86/kernel/cpu/mce/core.c | 88 ++++++++++++++++++---------------
 1 file changed, 48 insertions(+), 40 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 7fd86c8..5dec0da 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -715,6 +715,52 @@ static noinstr void mce_read_aux(struct mce_hw_err *err, int i)
 DEFINE_PER_CPU(unsigned, mce_poll_count);
 
 /*
+ * Newer Intel systems that support software error
+ * recovery need to make additional checks. Other
+ * CPUs should skip over uncorrected errors, but log
+ * everything else.
+ */
+static bool ser_should_log_poll_error(struct mce *m)
+{
+	/* Log "not enabled" (speculative) errors */
+	if (!(m->status & MCI_STATUS_EN))
+		return true;
+
+	/*
+	 * Log UCNA (SDM: 15.6.3 "UCR Error Classification")
+	 * UC == 1 && PCC == 0 && S == 0
+	 */
+	if (!(m->status & MCI_STATUS_PCC) && !(m->status & MCI_STATUS_S))
+		return true;
+
+	return false;
+}
+
+static bool should_log_poll_error(enum mcp_flags flags, struct mce_hw_err *err)
+{
+	struct mce *m = &err->m;
+
+	/* If this entry is not valid, ignore it. */
+	if (!(m->status & MCI_STATUS_VAL))
+		return false;
+
+	/*
+	 * If we are logging everything (at CPU online) or this
+	 * is a corrected error, then we must log it.
+	 */
+	if ((flags & MCP_UC) || !(m->status & MCI_STATUS_UC))
+		return true;
+
+	if (mca_cfg.ser)
+		return ser_should_log_poll_error(m);
+
+	if (m->status & MCI_STATUS_UC)
+		return false;
+
+	return true;
+}
+
+/*
  * Poll for corrected events or events that happened before reset.
  * Those are just logged through /dev/mcelog.
  *
@@ -765,48 +811,10 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 		if (!mca_cfg.cmci_disabled)
 			mce_track_storm(m);
 
-		/* If this entry is not valid, ignore it */
-		if (!(m->status & MCI_STATUS_VAL))
+		/* Verify that the error should be logged based on hardware conditions. */
+		if (!should_log_poll_error(flags, &err))
 			continue;
 
-		/*
-		 * If we are logging everything (at CPU online) or this
-		 * is a corrected error, then we must log it.
-		 */
-		if ((flags & MCP_UC) || !(m->status & MCI_STATUS_UC))
-			goto log_it;
-
-		/*
-		 * Newer Intel systems that support software error
-		 * recovery need to make additional checks. Other
-		 * CPUs should skip over uncorrected errors, but log
-		 * everything else.
-		 */
-		if (!mca_cfg.ser) {
-			if (m->status & MCI_STATUS_UC)
-				continue;
-			goto log_it;
-		}
-
-		/* Log "not enabled" (speculative) errors */
-		if (!(m->status & MCI_STATUS_EN))
-			goto log_it;
-
-		/*
-		 * Log UCNA (SDM: 15.6.3 "UCR Error Classification")
-		 * UC == 1 && PCC == 0 && S == 0
-		 */
-		if (!(m->status & MCI_STATUS_PCC) && !(m->status & MCI_STATUS_S))
-			goto log_it;
-
-		/*
-		 * Skip anything else. Presumption is that our read of this
-		 * bank is racing with a machine check. Leave the log alone
-		 * for do_machine_check() to deal with it.
-		 */
-		continue;
-
-log_it:
 		mce_read_aux(&err, i);
 		m->severity = mce_severity(m, NULL, NULL, false);
 		/*