• Jan Beulich's avatar
    x86-64: Don't apply destructive erratum workaround on unaffected CPUs · e05139f2
    Jan Beulich authored
    
    
    Erratum 93 applies to AMD K8 CPUs only, and its workaround
    (forcing the upper 32 bits of %rip to all get set under certain
    conditions) is actually getting in the way of analyzing page
    faults occurring during EFI physical mode runtime calls (in
    particular the page table walk shown is completely unrelated to
    the actual fault). This is because typically EFI runtime code
    lives in the space between 2G and 4G, which - modulo the above
    manipulation - is likely to overlap with the kernel or modules
    area.
    
    While even for the other errata workarounds their taking effect
    could be limited to just the affected CPUs, none of them appears
    to be destructive, and they're generally getting called only
    outside of performance critical paths, so they're being left
    untouched.
    Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
    Link: http://lkml.kernel.org/r/4E835FE30200007800058464@nat28.tlf.novell.com
    
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    e05139f2
fault.c 28.4 KB