Re: [RFC PATCH gnumach 03/34] Make exception subcode a long

[Samuel Thibault]

Hello,

Flávio Cruz, le mer. 05 avril 2023 22:11:38 -0400, a ecrit:
> On Mon, Apr 3, 2023 at 5:32 AM Sergey Bugaev via Libc-alpha <[1]
> libc-alpha@sourceware.org> wrote:
> 
>     On Mon, Apr 3, 2023 at 1:45 AM Samuel Thibault 
> <[2]samuel.thibault@gnu.org>
>     wrote:
>     > Sergey Bugaev, le dim. 19 mars 2023 18:09:46 +0300, a ecrit:
>     > > On EXC_BAD_ACCESS, exception subcode is used to pass the faulting
>     memory
>     > > address, so it needs to be (at least) pointer-sized. Thus, make it 
> into
>     > > a long.
>     > >
>     > > This requires matching changes in glibc and the Hurd.
>     >
>     > But the change doesn't affect 32bit glibc and hurd since
>     > rpc_long_integer_t is really like integer_t there, right?
> 
>     It's supposed to be ABI-compatible on 32-bit, since all these types
>     are 32-bit integers there, yes. (But maybe I messed up, do check!)
> 
>     But it may break source-level compatibility (if you only apply the
>     Mach change but not glibc, or vice versa); as in maybe GCC will
>     complain about int vs long in function prototype vs definition. I
>     haven't actually checked, since I have both changes applied locally.
> 
> 
> It breaks compatibility for Hurd code:
> 
> hurd/mach-defpager/default_pager.c:3789:1: error: conflicting types for
> 'catch_exception_raise'; have 'kern_return_t(mach_port_t, mach_port_t,
> mach_port_t, int, int, int)' {aka 'int(unsigned int, unsigned int, unsigned
> int, int, int, int)'}
> 3789 | catch_exception_raise(mach_port_t exception_port,
> | ^~~~~~~~~~~~~~~~~~~~~
> In file included from /home/runner/_work/cross-hurd/cross-hurd/src/hurd/
> mach-defpager/default_pager.c:67:
> ./exc_S.h:19:15: note: previous declaration of 'catch_exception_raise' with
> type 'kern_return_t(mach_port_t, mach_port_t, mach_port_t, integer_t,
> integer_t, rpc_long_integer_t)' {aka 'int(unsigned int, unsigned int, unsigned
> int, int, int, long int)'}
> 19 | kern_return_t catch_exception_raise

I have uploaded the fixes as debian packages, in addition to the commits
upstream.

Samuel