• Andi Kleen's avatar
    x86, mce: use 64bit machine check code on 32bit · 4efc0670
    Andi Kleen authored
    The 64bit machine check code is in many ways much better than
    the 32bit machine check code: it is more specification compliant,
    is cleaner, only has a single code base versus one per CPU,
    has better infrastructure for recovery, has a cleaner way to communicate
    with user space etc. etc.
    
    Use the 64bit code for 32bit too.
    
    This is the second attempt to do this. There was one a couple of years
    ago to unify this code for 32bit and 64bit.  Back then this ran into some
    trouble with K7s and was reverted.
    
    I believe this time the K7 problems (and some others) are addressed.
    I went over the old handlers and was very careful to retain
    all quirks.
    
    But of course this needs a lot of testing on old systems. On newer
    64bit capable systems I don't expect much problems because they have been
    already tested with the 64bit kernel.
    
    I made this a CONFIG for now that still allows to select the old
    machine check code. This is mostly to make testing easier,
    if someone runs into a problem we can ask them to try
    with the CONFIG switched.
    
    The new code is default y for more coverage.
    
    Once there is confidence the 64bit code works well on older hardware
    too the CONFIG_X86_OLD_MCE and the associated code can be easily
    removed.
    
    This causes a behaviour change for 32bit installations. They now
    have to install the mcelog package to be able to log
    corrected machine checks.
    
    The 64bit machine check code only handles CPUs which support the
    standard Intel machine check architecture described in the IA32 SDM.
    The 32bit code has special support for some older CPUs which
    have non standard machine check architectures, in particular
    WinChip C3 and Intel P5.  I made those a separate CONFIG option
    and kept them for now. The WinChip variant could be probably
    removed without too much pain, it doesn't really do anything
    interesting. P5 is also disabled by default (like it
    was before) because many motherboards have it miswired, but
    according to Alan Cox a few embedded setups use that one.
    
    Forward ported/heavily changed version of old patch, original patch
    included review/fixes from Thomas Gleixner, Bert Wesarg.
    Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
    Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
    Signed-off-by: default avatarHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
    Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
    4efc0670
traps.c 24.1 KB