8f4e956b31
When a machine check or NMI occurs while multiple byte code is patched the CPU could theoretically see an inconsistent instruction and crash. Prevent this by temporarily disabling MCEs and returning early in the NMI handler. Based on discussion with Mathieu Desnoyers. Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
91 lines
1.8 KiB
C
91 lines
1.8 KiB
C
/*
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* mce.c - x86 Machine Check Exception Reporting
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* (c) 2002 Alan Cox <alan@redhat.com>, Dave Jones <davej@codemonkey.org.uk>
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*/
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/smp.h>
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#include <linux/thread_info.h>
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#include <asm/processor.h>
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#include <asm/system.h>
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#include <asm/mce.h>
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#include "mce.h"
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int mce_disabled = 0;
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int nr_mce_banks;
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EXPORT_SYMBOL_GPL(nr_mce_banks); /* non-fatal.o */
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/* Handle unconfigured int18 (should never happen) */
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static fastcall void unexpected_machine_check(struct pt_regs * regs, long error_code)
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{
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printk(KERN_ERR "CPU#%d: Unexpected int18 (Machine Check).\n", smp_processor_id());
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}
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/* Call the installed machine check handler for this CPU setup. */
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void fastcall (*machine_check_vector)(struct pt_regs *, long error_code) = unexpected_machine_check;
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/* This has to be run for each processor */
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void mcheck_init(struct cpuinfo_x86 *c)
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{
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if (mce_disabled==1)
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return;
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switch (c->x86_vendor) {
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case X86_VENDOR_AMD:
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amd_mcheck_init(c);
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break;
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case X86_VENDOR_INTEL:
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if (c->x86==5)
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intel_p5_mcheck_init(c);
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if (c->x86==6)
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intel_p6_mcheck_init(c);
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if (c->x86==15)
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intel_p4_mcheck_init(c);
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break;
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case X86_VENDOR_CENTAUR:
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if (c->x86==5)
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winchip_mcheck_init(c);
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break;
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default:
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break;
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}
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}
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static unsigned long old_cr4 __initdata;
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void __init stop_mce(void)
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{
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old_cr4 = read_cr4();
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clear_in_cr4(X86_CR4_MCE);
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}
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void __init restart_mce(void)
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{
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if (old_cr4 & X86_CR4_MCE)
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set_in_cr4(X86_CR4_MCE);
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}
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static int __init mcheck_disable(char *str)
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{
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mce_disabled = 1;
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return 1;
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}
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static int __init mcheck_enable(char *str)
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{
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mce_disabled = -1;
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return 1;
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}
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__setup("nomce", mcheck_disable);
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__setup("mce", mcheck_enable);
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