• Dave Hansen's avatar
    x86, mpx: Explicitly disable 32-bit MPX support on 64-bit kernels · 814564a0
    Dave Hansen authored
    We had originally planned on submitting MPX support in one patch
    set.  We eventually broke it up in to two pieces for easier
    review.  One of the features that didn't make the first round
    was supporting 32-bit binaries on 64-bit kernels.
    
    Once we split the set up, we never added code to restrict 32-bit
    binaries from _using_ MPX on 64-bit kernels.
    
    The 32-bit bounds tables are a different format than the 64-bit
    ones.  Without this patch, the kernel will try to read a 32-bit
    binary's tables as if they were the 64-bit version.  They will
    likely be noticed as being invalid rather quickly and the app
    will get killed, but that's kinda mean.
    
    This patch adds an explicit check, and will make a 64-bit kernel
    essentially behave as if it has no MPX support when called from
    a 32-bit binary.
    Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Dave Hansen <dave@sr71.net>
    Link: http://lkml.kernel.org/r/20150108223020.9E9AA511@viggo.jf.intel.comSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    814564a0
mpx.c 24.3 KB