• Zachary Amsden's avatar
    [PATCH] i386: inline asm cleanup · 4bb0d3ec
    Zachary Amsden authored
    i386 Inline asm cleanup.  Use cr/dr accessor functions.
    Also, a potential bugfix.  Also, some CR accessors really should be volatile.
    Reads from CR0 (numeric state may change in an exception handler), writes to
    CR4 (flipping CR4.TSD) and reads from CR2 (page fault) prevent instruction
    re-ordering.  I did not add memory clobber to CR3 / CR4 / CR0 updates, as it
    was not there to begin with, and in no case should kernel memory be clobbered,
    except when doing a TLB flush, which already has memory clobber.
    I noticed that page invalidation does not have a memory clobber.  I can't find
    a bug as a result, but there is definitely a potential for a bug here:
    #define __flush_tlb_single(addr) \
    	__asm__ __volatile__("invlpg %0": :"m" (*(char *) addr))
    Signed-off-by: default avatarZachary Amsden <zach@vmware.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>