On 02/22/2012 03:51 PM, Andrew Lutomirski wrote: > On Wed, Feb 22, 2012 at 3:46 PM, Indan Zupancic <indan@xxxxxx> wrote: >> On Wed, February 22, 2012 20:47, Will Drewry wrote: >>> On Wed, Feb 22, 2012 at 8:23 AM, Ben Hutchings >>>> I would have thought the way to make sure the architecture is always >>>> checked is to pack it together with the syscall number. >> >> I missed that suggestion, putting the syscall number and arch in one >> data field would indeed make it harder to not check the arch. > > Is there enough room? On x86-64 at least, rax could conceivably be > extended to 64 bits some day. Bit 30 is already spoken for by x32. > No it couldn't, because we mask off the high 32 bits and thus it could (theoretically) break user space. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
