On Mon, Apr 11, 2022 at 10:26 AM Sören Tempel <soe...@soeren-tempel.net> wrote:
>
> Any updates no this?
>
> Sorry I keep bothering you with this but we are quite literally only a
> few lines away from having the go-signal.c code compile on PPC64 musl :)
>
> Let me know if you need more information to get this fixed.
What I was hoping from my earlier question was that you could tell me
the exact lines to write in the current sources that will compile on
MUSL. Don't include <asm/ptrace.h>, don't refer to earlier patches as
that is what I tried to do earlier but failed, don't add new #define
macros, just add #ifdef and appropriate lines. Thanks. If the new
lines also work on glibc using register indexes rather than names,
that would be a bonus.
Ian
> Sören Tempel <soe...@soeren-tempel.net> wrote:
> > Ian Lance Taylor <i...@golang.org> wrote:
> > > Sorry, I guess I misread your patch.
> >
> > No problem, I think this stuff is hard to get right and understand in
> > general since it is so poorly documented.
> >
> > > What is the right standalone code for the PPC64 musl case? Thanks.
> >
> > In order to have the current code (i.e. current gofrontend HEAD with
> > your patch) compile and work with PPC64 musl it would be sufficient to
> > just include asm/ptrace.h, as proposed in the v1 of my patch [1]:
> >
> > // On PowerPC, ucontext.h uses a pt_regs struct as an incomplete
> > // type. This type must be completed by including asm/ptrace.h.
> > #ifdef __PPC__
> > #include <asm/ptrace.h>
> > #endif
> >
> > Technically, this should also be needed for using .regs on glibc since
> > it also declares pt_regs as in incomplete type [5]. As such, adding the
> > include may be the easiest way to resolve this issue.
> >
> > However, based on your feedback [2] and feedback by Rich Felker [3]. I
> > rewrote the go-signal.c PowerPC register handling code to not use .regs
> > ("Having pt_regs appear at all in code not using ptrace is a serious
> > code smell"). See the v4 of my patch for details [4]. If you don't want
> > to use .regs on PPC64 musl the right standalone code should be:
> >
> > ((ucontext_t*)(context))->uc_mcontext.gp_regs;
> >
> > Unfortunately, this code only works on PPC64 musl and PPC64 glibc not on
> > PPC32 glibc and PPC32 musl, thus I added a case distinction in the v4 of
> > my patch [4]. For my personal needs it would be very much sufficient to
> > just add an include of asm/ptrace.h to go-signal.c to make the current
> > code (i.e. your patch) also work with PPC64 musl.
> >
> > Greetings,
> > Sören
> >
> > [1]: https://gcc.gnu.org/pipermail/gcc-patches/2022-January/587520.html
> > [2]: https://gcc.gnu.org/pipermail/gcc-patches/2022-February/590668.html
> > [3]: https://gcc.gnu.org/pipermail/gcc-patches/2022-March/591257.html
> > [4]: https://gcc.gnu.org/pipermail/gcc-patches/2022-March/591593.html
> > [5]:
> > https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h;hb=6ff3c7714900529b8f5ca64b58d5da9cd5d5b345#l33
