1 files changed, 53 insertions, 76 deletions

diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 7aa2bda93cbb..00483d1c27e4 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -301,90 +301,68 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs)
 	}
 }
 
-static int mce_severity_amd_smca(struct mce *m, enum context err_ctx)
+/* See AMD PPR(s) section Machine Check Error Handling. */
+static noinstr int mce_severity_amd(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
 {
-	u64 mcx_cfg;
+	char *panic_msg = NULL;
+	int ret;
 
 	/*
-	 * We need to look at the following bits:
-	 * - "succor" bit (data poisoning support), and
-	 * - TCC bit (Task Context Corrupt)
-	 * in MCi_STATUS to determine error severity.
+	 * Default return value: Action required, the error must be handled
+	 * immediately.
 	 */
-	if (!mce_flags.succor)
-		return MCE_PANIC_SEVERITY;
-
-	mcx_cfg = mce_rdmsrl(MSR_AMD64_SMCA_MCx_CONFIG(m->bank));
-
-	/* TCC (Task context corrupt). If set and if IN_KERNEL, panic. */
-	if ((mcx_cfg & MCI_CONFIG_MCAX) &&
-	    (m->status & MCI_STATUS_TCC) &&
-	    (err_ctx == IN_KERNEL))
-		return MCE_PANIC_SEVERITY;
-
-	 /* ...otherwise invoke hwpoison handler. */
-	return MCE_AR_SEVERITY;
-}
-
-/*
- * See AMD Error Scope Hierarchy table in a newer BKDG. For example
- * 49125_15h_Models_30h-3Fh_BKDG.pdf, section "RAS Features"
- */
-static noinstr int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant,
-				    char **msg, bool is_excp)
-{
-	enum context ctx = error_context(m, regs);
+	ret = MCE_AR_SEVERITY;
 
 	/* Processor Context Corrupt, no need to fumble too much, die! */
-	if (m->status & MCI_STATUS_PCC)
-		return MCE_PANIC_SEVERITY;
-
-	if (m->status & MCI_STATUS_UC) {
-
-		if (ctx == IN_KERNEL)
-			return MCE_PANIC_SEVERITY;
+	if (m->status & MCI_STATUS_PCC) {
+		panic_msg = "Processor Context Corrupt";
+		ret = MCE_PANIC_SEVERITY;
+		goto out;
+	}
 
-		/*
-		 * On older systems where overflow_recov flag is not present, we
-		 * should simply panic if an error overflow occurs. If
-		 * overflow_recov flag is present and set, then software can try
-		 * to at least kill process to prolong system operation.
-		 */
-		if (mce_flags.overflow_recov) {
-			if (mce_flags.smca)
-				return mce_severity_amd_smca(m, ctx);
-
-			/* kill current process */
-			return MCE_AR_SEVERITY;
-		} else {
-			/* at least one error was not logged */
-			if (m->status & MCI_STATUS_OVER)
-				return MCE_PANIC_SEVERITY;
-		}
-
-		/*
-		 * For any other case, return MCE_UC_SEVERITY so that we log the
-		 * error and exit #MC handler.
-		 */
-		return MCE_UC_SEVERITY;
+	if (m->status & MCI_STATUS_DEFERRED) {
+		ret = MCE_DEFERRED_SEVERITY;
+		goto out;
 	}
 
 	/*
-	 * deferred error: poll handler catches these and adds to mce_ring so
-	 * memory-failure can take recovery actions.
+	 * If the UC bit is not set, the system either corrected or deferred
+	 * the error. No action will be required after logging the error.
 	 */
-	if (m->status & MCI_STATUS_DEFERRED)
-		return MCE_DEFERRED_SEVERITY;
+	if (!(m->status & MCI_STATUS_UC)) {
+		ret = MCE_KEEP_SEVERITY;
+		goto out;
+	}
 
 	/*
-	 * corrected error: poll handler catches these and passes responsibility
-	 * of decoding the error to EDAC
+	 * On MCA overflow, without the MCA overflow recovery feature the
+	 * system will not be able to recover, panic.
 	 */
-	return MCE_KEEP_SEVERITY;
+	if ((m->status & MCI_STATUS_OVER) && !mce_flags.overflow_recov) {
+		panic_msg = "Overflowed uncorrected error without MCA Overflow Recovery";
+		ret = MCE_PANIC_SEVERITY;
+		goto out;
+	}
+
+	if (!mce_flags.succor) {
+		panic_msg = "Uncorrected error without MCA Recovery";
+		ret = MCE_PANIC_SEVERITY;
+		goto out;
+	}
+
+	if (error_context(m, regs) == IN_KERNEL) {
+		panic_msg = "Uncorrected unrecoverable error in kernel context";
+		ret = MCE_PANIC_SEVERITY;
+	}
+
+out:
+	if (msg && panic_msg)
+		*msg = panic_msg;
+
+	return ret;
 }
 
-static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs,
-				      int tolerant, char **msg, bool is_excp)
+static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
 {
 	enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP);
 	enum context ctx = error_context(m, regs);
@@ -412,22 +390,21 @@ static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs,
 		if (msg)
 			*msg = s->msg;
 		s->covered = 1;
-		if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) {
-			if (tolerant < 1)
-				return MCE_PANIC_SEVERITY;
-		}
+
+		if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL)
+			return MCE_PANIC_SEVERITY;
+
 		return s->sev;
 	}
 }
 
-int noinstr mce_severity(struct mce *m, struct pt_regs *regs, int tolerant, char **msg,
-			 bool is_excp)
+int noinstr mce_severity(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
 {
 	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
 	    boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
-		return mce_severity_amd(m, regs, tolerant, msg, is_excp);
+		return mce_severity_amd(m, regs, msg, is_excp);
 	else
-		return mce_severity_intel(m, regs, tolerant, msg, is_excp);
+		return mce_severity_intel(m, regs, msg, is_excp);
 }
 
 #ifdef CONFIG_DEBUG_FS