1 files changed, 69 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/p5.c b/arch/x86/kernel/cpu/mcheck/p5.c
new file mode 100644
index 000000000..5cddf8317
--- /dev/null
+++ b/arch/x86/kernel/cpu/mcheck/p5.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * P5 specific Machine Check Exception Reporting
+ * (C) Copyright 2002 Alan Cox <alan@lxorguk.ukuu.org.uk>
+ */
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/smp.h>
+
+#include <asm/processor.h>
+#include <asm/traps.h>
+#include <asm/tlbflush.h>
+#include <asm/mce.h>
+#include <asm/msr.h>
+
+/* By default disabled */
+int mce_p5_enabled __read_mostly;
+
+/* Machine check handler for Pentium class Intel CPUs: */
+static void pentium_machine_check(struct pt_regs *regs, long error_code)
+{
+	u32 loaddr, hi, lotype;
+
+	ist_enter(regs);
+
+	rdmsr(MSR_IA32_P5_MC_ADDR, loaddr, hi);
+	rdmsr(MSR_IA32_P5_MC_TYPE, lotype, hi);
+
+	pr_emerg("CPU#%d: Machine Check Exception:  0x%8X (type 0x%8X).\n",
+		 smp_processor_id(), loaddr, lotype);
+
+	if (lotype & (1<<5)) {
+		pr_emerg("CPU#%d: Possible thermal failure (CPU on fire ?).\n",
+			 smp_processor_id());
+	}
+
+	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
+
+	ist_exit(regs);
+}
+
+/* Set up machine check reporting for processors with Intel style MCE: */
+void intel_p5_mcheck_init(struct cpuinfo_x86 *c)
+{
+	u32 l, h;
+
+	/* Default P5 to off as its often misconnected: */
+	if (!mce_p5_enabled)
+		return;
+
+	/* Check for MCE support: */
+	if (!cpu_has(c, X86_FEATURE_MCE))
+		return;
+
+	machine_check_vector = pentium_machine_check;
+	/* Make sure the vector pointer is visible before we enable MCEs: */
+	wmb();
+
+	/* Read registers before enabling: */
+	rdmsr(MSR_IA32_P5_MC_ADDR, l, h);
+	rdmsr(MSR_IA32_P5_MC_TYPE, l, h);
+	pr_info("Intel old style machine check architecture supported.\n");
+
+	/* Enable MCE: */
+	cr4_set_bits(X86_CR4_MCE);
+	pr_info("Intel old style machine check reporting enabled on CPU#%d.\n",
+		smp_processor_id());
+}