On Thu, Oct 01, 2015 at 07:36:54PM +0200, Mathias Krause wrote: > On Do, Okt 01, 2015 at 08:29:50 -0500, Josh Poimboeuf wrote: > > On Thu, Oct 01, 2015 at 08:10:26AM +0200, minipli@xxxxxxxxxxx wrote: > > > On Tue, Sep 22, 2015 at 10:47:04AM -0500, Josh Poimboeuf wrote: > > > > ENTRY(aesni_set_key) > > > > + FRAME_BEGIN > > > > #ifndef __x86_64__ > > > > pushl KEYP > > > > movl 8(%esp), KEYP # ctx > > > > > > This will break 32 bit builds using the aesni-intel.ko module. You need > > > to adjust the esp-based offsets for the non-x86_64 case, as FRAME_BEGIN > > > may do another push. > > > > > > How about adding a FRAME_OFFSET() macro to <asm/frame.h> to wrap the > > > offsets?: > > > > > > #ifdef CONFIG_FRAME_POINTER > > > # define FRAME_OFFSET(x) ((x) + (BITS_PER_LONG / 8)) > > > #else > > > # define FRAME_OFFSET(x) (x) > > > #endif > > > > > > And using them like this: > > > > > > movl FRAME_OFFSET(8)(%esp), KEYP # ctx > > > > Ah, right. The 32-bit ABI passes arguments on the stack instead of via > > registers. > > > > For now, I'm inclined to just make FRAME_BEGIN and FRAME_END do nothing > > on 32-bit. We're only doing stack validation on x86_64 and I don't know > > if anybody cares about frame pointers on 32-bit at this point. > > Well, we had issues in the past, especially in that very module, but > only on 32 bit systems. So it would be nice to get frame pointers right > for 32 bit, too. Ok, I'll make your suggested changes for this file with FRAME_OFFSET. (But note that stacktool doesn't currently support 32 bit so it won't detect any frame pointer issues in 32 bit code.) -- Josh -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
