Re: Formal description of system call interface

[Szabolcs Nagy <nsz@port70.net>]

* Dmitry Vyukov <dvyukov@google.com> [2016-11-21 16:03:04 +0100]:
> On Mon, Nov 7, 2016 at 1:28 AM, Szabolcs Nagy <nsz@port70.net> wrote:
> > * Dmitry Vyukov <dvyukov@google.com> [2016-11-06 14:39:28 -0800]:
> >> For the reference, current syzkaller descriptions are in txt files here:
> >> https://github.com/google/syzkaller/tree/master/sys
> > ...
> >> Taking the opportunity, if you see that something is missing/wrong
> >> in the descriptions of the subsystem you care about, or if it is not
> >> described at all, fixes are welcome.
> >
> > abi variants are missing (abi variation makes a lot of
> > syscall interface related work painful).
> 
> 
> What exactly do you mean by "abi variants"? Is it architecture?
> What exactly needs to be added to the descriptions support "abi variants?
> 

abi variant is a supported syscall abi
(linux supports several abis on the same arch:
e.g. x86 has i386,x86_64,x32 one might also
call different endianness a different abi, but
i'd expect le/be to be handled together.)

available syscalls, argument types and ordering
can be different across abis

i may be wrong, but i did not see those handled
in sys.txt, looking at it now i see missing
paddings in ipc structs (*_ds) so it may not
work the way i assumed (these are types which
have some abi variation).