cvs commit: src/sys/i386/include specialreg.h src/sys/i386/i386 identcpu.c

David Xu davidxu at
Mon Jun 19 08:11:24 UTC 2006

davidxu     2006-06-19 07:51:47 UTC

  FreeBSD src repository

  Modified files:
    sys/i386/include     specialreg.h 
    sys/i386/i386        identcpu.c 
  Clear bit 22 in MSR IA32_MISC_ENABLE, according to Intel document,
  when the bit 22 is set to 1, CPUID with EAX=0 returns a maximum
  value in EAX[7..0] of 3, when set to 0(default), CPUID with EAX=0
  returns the number corresponding to the maximum standard function
  supported. On my machine, BIOS sets the bit to 1 to make it to be
  compatible with old OS, this causes dual-core Pentium-D (two
  physical cores) to be identified as hyperthreading (two logical
  cores) by function mp_topology().
  Revision  Changes    Path
  1.163     +11 -0     src/sys/i386/i386/identcpu.c
  1.30      +1 -0      src/sys/i386/include/specialreg.h

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