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p6.c

/*
 * P6 specific Machine Check Exception Reporting
 * (C) Copyright 2002 Alan Cox <alan@redhat.com>
 */

#include <linux/init.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/smp.h>

#include <asm/processor.h> 
#include <asm/system.h>
#include <asm/msr.h>

#include "mce.h"

/* Machine Check Handler For PII/PIII */
static fastcall void intel_machine_check(struct pt_regs * regs, long error_code)
{
      int recover=1;
      u32 alow, ahigh, high, low;
      u32 mcgstl, mcgsth;
      int i;

      rdmsr (MSR_IA32_MCG_STATUS, mcgstl, mcgsth);
      if (mcgstl & (1<<0))    /* Recoverable ? */
            recover=0;

      printk (KERN_EMERG "CPU %d: Machine Check Exception: %08x%08x\n",
            smp_processor_id(), mcgsth, mcgstl);

      for (i=0; i<nr_mce_banks; i++) {
            rdmsr (MSR_IA32_MC0_STATUS+i*4,low, high);
            if (high & (1<<31)) {
                  if (high & (1<<29))
                        recover |= 1;
                  if (high & (1<<25))
                        recover |= 2;
                  printk (KERN_EMERG "Bank %d: %08x%08x", i, high, low);
                  high &= ~(1<<31);
                  if (high & (1<<27)) {
                        rdmsr (MSR_IA32_MC0_MISC+i*4, alow, ahigh);
                        printk ("[%08x%08x]", ahigh, alow);
                  }
                  if (high & (1<<26)) {
                        rdmsr (MSR_IA32_MC0_ADDR+i*4, alow, ahigh);
                        printk (" at %08x%08x", ahigh, alow);
                  }
                  printk ("\n");
            }
      }

      if (recover & 2)
            panic ("CPU context corrupt");
      if (recover & 1)
            panic ("Unable to continue");

      printk (KERN_EMERG "Attempting to continue.\n");
      /* 
       * Do not clear the MSR_IA32_MCi_STATUS if the error is not 
       * recoverable/continuable.This will allow BIOS to look at the MSRs
       * for errors if the OS could not log the error.
       */
      for (i=0; i<nr_mce_banks; i++) {
            unsigned int msr;
            msr = MSR_IA32_MC0_STATUS+i*4;
            rdmsr (msr,low, high);
            if (high & (1<<31)) {
                  /* Clear it */
                  wrmsr (msr, 0UL, 0UL);
                  /* Serialize */
                  wmb();
                  add_taint(TAINT_MACHINE_CHECK);
            }
      }
      mcgstl &= ~(1<<2);
      wrmsr (MSR_IA32_MCG_STATUS,mcgstl, mcgsth);
}

/* Set up machine check reporting for processors with Intel style MCE */
void intel_p6_mcheck_init(struct cpuinfo_x86 *c)
{
      u32 l, h;
      int i;
      
      /* Check for MCE support */
      if (!cpu_has(c, X86_FEATURE_MCE))
            return;

      /* Check for PPro style MCA */
      if (!cpu_has(c, X86_FEATURE_MCA))
            return;

      /* Ok machine check is available */
      machine_check_vector = intel_machine_check;
      wmb();

      printk (KERN_INFO "Intel machine check architecture supported.\n");
      rdmsr (MSR_IA32_MCG_CAP, l, h);
      if (l & (1<<8))   /* Control register present ? */
            wrmsr(MSR_IA32_MCG_CTL, 0xffffffff, 0xffffffff);
      nr_mce_banks = l & 0xff;

      /*
       * Following the example in IA-32 SDM Vol 3:
       * - MC0_CTL should not be written
       * - Status registers on all banks should be cleared on reset
       */
      for (i=1; i<nr_mce_banks; i++)
            wrmsr (MSR_IA32_MC0_CTL+4*i, 0xffffffff, 0xffffffff);

      for (i=0; i<nr_mce_banks; i++)
            wrmsr (MSR_IA32_MC0_STATUS+4*i, 0x0, 0x0);

      set_in_cr4 (X86_CR4_MCE);
      printk (KERN_INFO "Intel machine check reporting enabled on CPU#%d.\n",
            smp_processor_id());
}

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