xref: /linux/arch/x86/kernel/cpu/mce/p5.c (revision 37744feebc086908fd89760650f458ab19071750)
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 #include "internal.h"
18 
19 /* By default disabled */
20 int mce_p5_enabled __read_mostly;
21 
22 /* Machine check handler for Pentium class Intel CPUs: */
23 static void pentium_machine_check(struct pt_regs *regs, long error_code)
24 {
25 	u32 loaddr, hi, lotype;
26 
27 	ist_enter(regs);
28 
29 	rdmsr(MSR_IA32_P5_MC_ADDR, loaddr, hi);
30 	rdmsr(MSR_IA32_P5_MC_TYPE, lotype, hi);
31 
32 	pr_emerg("CPU#%d: Machine Check Exception:  0x%8X (type 0x%8X).\n",
33 		 smp_processor_id(), loaddr, lotype);
34 
35 	if (lotype & (1<<5)) {
36 		pr_emerg("CPU#%d: Possible thermal failure (CPU on fire ?).\n",
37 			 smp_processor_id());
38 	}
39 
40 	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
41 
42 	ist_exit(regs);
43 }
44 
45 /* Set up machine check reporting for processors with Intel style MCE: */
46 void intel_p5_mcheck_init(struct cpuinfo_x86 *c)
47 {
48 	u32 l, h;
49 
50 	/* Default P5 to off as its often misconnected: */
51 	if (!mce_p5_enabled)
52 		return;
53 
54 	/* Check for MCE support: */
55 	if (!cpu_has(c, X86_FEATURE_MCE))
56 		return;
57 
58 	machine_check_vector = pentium_machine_check;
59 	/* Make sure the vector pointer is visible before we enable MCEs: */
60 	wmb();
61 
62 	/* Read registers before enabling: */
63 	rdmsr(MSR_IA32_P5_MC_ADDR, l, h);
64 	rdmsr(MSR_IA32_P5_MC_TYPE, l, h);
65 	pr_info("Intel old style machine check architecture supported.\n");
66 
67 	/* Enable MCE: */
68 	cr4_set_bits(X86_CR4_MCE);
69 	pr_info("Intel old style machine check reporting enabled on CPU#%d.\n",
70 		smp_processor_id());
71 }
72