1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * P5 specific Machine Check Exception Reporting
 4 * (C) Copyright 2002 Alan Cox <alan@lxorguk.ukuu.org.uk>
 5 */
 6#include <linux/interrupt.h>
 7#include <linux/kernel.h>
 8#include <linux/types.h>
 9#include <linux/smp.h>
10
11#include <asm/processor.h>
12#include <asm/traps.h>
13#include <asm/tlbflush.h>
14#include <asm/mce.h>
15#include <asm/msr.h>
16
17/* By default disabled */
18int mce_p5_enabled __read_mostly;
19
20/* Machine check handler for Pentium class Intel CPUs: */
21static void pentium_machine_check(struct pt_regs *regs, long error_code)
22{
23	u32 loaddr, hi, lotype;
24
25	ist_enter(regs);
26
27	rdmsr(MSR_IA32_P5_MC_ADDR, loaddr, hi);
28	rdmsr(MSR_IA32_P5_MC_TYPE, lotype, hi);
29
30	pr_emerg("CPU#%d: Machine Check Exception:  0x%8X (type 0x%8X).\n",
31		 smp_processor_id(), loaddr, lotype);
32
33	if (lotype & (1<<5)) {
34		pr_emerg("CPU#%d: Possible thermal failure (CPU on fire ?).\n",
35			 smp_processor_id());
36	}
37
38	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
39
40	ist_exit(regs);
41}
42
43/* Set up machine check reporting for processors with Intel style MCE: */
44void intel_p5_mcheck_init(struct cpuinfo_x86 *c)
45{
46	u32 l, h;
47
48	/* Default P5 to off as its often misconnected: */
49	if (!mce_p5_enabled)
50		return;
51
52	/* Check for MCE support: */
53	if (!cpu_has(c, X86_FEATURE_MCE))
54		return;
55
56	machine_check_vector = pentium_machine_check;
57	/* Make sure the vector pointer is visible before we enable MCEs: */
58	wmb();
59
60	/* Read registers before enabling: */
61	rdmsr(MSR_IA32_P5_MC_ADDR, l, h);
62	rdmsr(MSR_IA32_P5_MC_TYPE, l, h);
63	pr_info("Intel old style machine check architecture supported.\n");
64
65	/* Enable MCE: */
66	cr4_set_bits(X86_CR4_MCE);
67	pr_info("Intel old style machine check reporting enabled on CPU#%d.\n",
68		smp_processor_id());
69}