Re: [PATCH v3] Remove stale pre-AIX-7.2 compatibility guards

[Simon Marchi <simon.marchi@polymtl.ca>]

On 9/22/26 12:52 AM, Aditya Vidyadhar Kamath wrote:
> From: Aditya Kamath <Aditya.Kamath1@ibm.com>
> 
> GDB now requires AIX 7.2 as the minimum supported version and will
> support AIX 7.2 TL5, AIX 7.3 and upcoming AIX releases.  Remove
> dead compatibility code that existed only for older releases.
> 
> Remove the HAVE_DECL_GETTHRDS configure check since aix-thread.c was the last
> user of that macro.  Merge ptrace64aix and ptrace32 into a single
> ptrace_aix function since they became identical after this
> cleanup, and collapse all call sites that branched on arch64 just to
> pick between the two.  Also clean up rs6000-aix-nat.c by removing the
> ARCH3264 and HAVE_PTRACE64 guards along with the ptracex fallback in
> rs6000_ptrace32 and rs6000_ptrace64, which are now simple wrappers
> around ptrace64.
> 
> Also as per https://www.ibm.com/docs/en/aix/7.2.0?topic=p-ptrace-ptracex-ptrace64-subroutine
> ptrace64 will also support 32-bit debugees.

On this page I see:

    For ptracex or ptrace64: If the debuggee is a 32-bit process, the
    options that refer to GPRs or SPRs fail with errno = EIO

And I see that in the patch, you call ptrace64 to read registers
(PTT_READ_GPRS) for 32 bit processes.  How does that work?

> @@ -315,40 +306,13 @@ ptrace_check (int req, int id, int ret)
>    return 0;  /* Not reached.  */
>  }
>  
> -/* Call ptracex (REQ, ID, ADDR, DATA, BUF) or
> -   ptrace64 (REQ, ID, ADDR, DATA, BUF) if HAVE_PTRACE64.
> -   Return success.  */
> -
> -#ifdef HAVE_PTRACE64
> -# define ptracex(request, pid, addr, data, buf) \
> -	 ptrace64 (request, pid, addr, data, buf)
> -#endif
> +/* Call ptrace64 (REQ, ID, ADDR, DATA, BUF).  Return success.  */

I think that all these "Call ptrace64" comments are not very useful.  We
can see that by reading the code.  Change the comment to explain why
this wrapper function needs to exist (if it really does).

I think you could simplify this one further by moving the actual
ptrace64 call into ptrace_check (so that it does the ptrace call and the
check), and get rid of ptraceaix.  There is one level of abstraction
that is not needed anymore here.

If you only rely on ptrace64 now, I'd suggest changing the "id"
parameters to "long long", to match the type of ptrace64.

Otherwise, that looks fine to me.  I'll let Ulrich check the more
specific AIX details.

Simon