On Fri, Jul 17, 2015 at 02:01:33PM -0700, Andy Lutomirski wrote: > On Fri, Jul 17, 2015 at 1:59 PM, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > On Fri, Jul 17, 2015 at 01:46:39PM -0700, Andy Lutomirski wrote: > >> On Fri, Jul 17, 2015 at 1:44 PM, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > >> > On Fri, Jul 17, 2015 at 01:39:09PM -0700, Andy Lutomirski wrote: > >> >> On Fri, Jul 17, 2015 at 1:37 PM, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > >> >> > On Fri, Jul 17, 2015 at 12:44:42PM -0700, Andy Lutomirski wrote: > >> >> >> On Fri, Jul 17, 2015 at 12:43 PM, Ingo Molnar <mingo@xxxxxxxxxx> wrote: > >> >> >> > > >> >> >> > * Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > >> >> >> > > >> >> >> >> ENTRY(aesni_set_key) > >> >> >> >> + FRAME > >> >> >> >> #ifndef __x86_64__ > >> >> >> >> pushl KEYP > >> >> >> >> movl 8(%esp), KEYP # ctx > >> >> >> >> @@ -1905,6 +1907,7 @@ ENTRY(aesni_set_key) > >> >> >> >> #ifndef __x86_64__ > >> >> >> >> popl KEYP > >> >> >> >> #endif > >> >> >> >> + ENDFRAME > >> >> >> >> ret > >> >> >> >> ENDPROC(aesni_set_key) > >> >> >> > > >> >> >> > So cannot we make this a bit more compact and less fragile? > >> >> >> > > >> >> >> > Instead of: > >> >> >> > > >> >> >> > ENTRY(aesni_set_key) > >> >> >> > FRAME > >> >> >> > ... > >> >> >> > ENDFRAME > >> >> >> > ret > >> >> >> > ENDPROC(aesni_set_key) > >> >> >> > > >> >> >> > > >> >> >> > How about writing this as: > >> >> >> > > >> >> >> > FUNCTION_ENTRY(aesni_set_key) > >> >> >> > ... > >> >> >> > FUNCTION_RETURN(aesni_set_key) > >> >> >> > > >> >> >> > which does the same thing in a short, symmetric construct? > >> >> >> > > >> >> >> > One potential problem with this approach would be that what 'looks' like an entry > >> >> >> > declaration, but it will now generate real code. > >> >> >> > > >> >> >> > OTOH if people find this intuitive enough then it's a lot harder to mess it up, > >> >> >> > and I think 'RETURN' makes it clear enough that there's a real instruction > >> >> >> > generated there. > >> >> >> > > >> >> >> > >> >> >> How about FUNCTION_PROLOGUE and FUNCTION_EPILOGUE? > >> >> > > >> >> > Perhaps the macro name should describe what the epilogue does, since > >> >> > frame pointers aren't required for _all_ functions, only those which > >> >> > don't have call instructions. > >> >> > > >> >> > What do you think about ENTRY_FRAME and ENDPROC_FRAME_RETURN? The > >> >> > ending macro is kind of long, but at least it a) matches the existing > >> >> > ENTRY/ENDPROC convention for asm functions; b) gives a clue that frame > >> >> > pointers are involved; and c) lets you know that the return is there. > >> >> > > >> >> > >> >> This really is about frame pointers, right? How about > >> >> ENTRY_FRAMEPTR_xyz where xyz can be prologue, epilogue, return, > >> >> whatever? > >> > > >> > Wouldn't the "ENTRY" in ENTRY_FRAMEPTR_RETURN be confusing at the end of > >> > a function? > >> > >> I meant ENTRY_FRAMEPTR_xyz and the beginning and ENDPROC_FRAMEPTR_xyz > >> (ENTRY is debatable, but that's what we currently have). ENDPROC > >> could easily be replaced with anything else. > > > > So do you mean ENTRY_FRAMEPTR_PROLOGUE and ENDPROC_FRAMEPTR_EPILOGUE? > > Or something else? > > > > I like it. I think this bikeshed might be well painted now! Actually I'm not done painting. Personally it seems a little too verbose. I still like ENTRY_FRAME and ENDPROC_FRAME_RETURN :p -- 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
