Sorry if this is a dup, I seem to be having mailer problems...

On Tue, 2006-04-25 at 21:38 +0200, Mark Kettenis wrote:
> > From: PAUL GILLIAM <pgilliam@us.ibm.com>
> > Date: Mon, 24 Apr 2006 17:23:13 -0700
> > 
> > Darn!  I forgot to 'trim' the patch'.
> > 
> > I have attached the 'trimmed' version.
> 
> Get rid of the PTRACE_XFER_TYPE and PTRACE_ARG3_TYPE.  Replace them
> with PTRACE_TYPE_RET and PTRACE_TYPE_ARG3.  Or better yet, if the
> prototype for ptrace(2) is consistent for all powerpc Linux variants,
> simply replace them with the proper type (which is probably "long").
> 
> Oh and while you're there, get rid of PT_READ_U/PT_WRITE_U in favour
> of PTRACE_PEEKUSR/PTRACE_POKEUSR.
> 
> Mark
> 
Changeing the PTRACE_... stuff had kind of a wrinkle (see below) 
but the big problem is with this line in ppc_linux_nat.c:

  last_stopped_data_address = (CORE_ADDR) siginfo.si_addr;

in subroutine ppc_linux_stopped_by_watchpoint()

A 'CORE_ADDR' is a 'bfd_vma' and on ppc64 systems, a 'bfd_vma' is an
'unsigned long long'.  If gdb is built on such a system with CC='gcc
-m64', an 'unsigned long long' is 64 bits as are an 'unsigned long' and
a 'void *'.  No problem.

But if CC is just 'gcc', then an 'unsigned long long' is still 64 bits,
but an 'unsigned long' and a 'void *' are 32 bits.

Changing the line to:
  last_stopped_data_address = (CORE_ADDR) (unsigned long)
siginfo.si_addr;

Fixes the problem because the extra cast does nothing when CC='gcc -m64'
but when CC='gcc', siginfo.si_addr is cast from a 'void *' to an integer
of the same size, which is then cast to an integer of a larger size,
avoiding the warning.

I have attached the new patch, OK to commit?

-=# Paul #=-

PS:

Here is the wrinkle

On a ppc64 system:

This is from /usr/include/sys/ptrace.h:
extern long int ptrace (enum __ptrace_request __request, ...) __THROW;

So I think PTRACE_TYPE_RET should default to 'long' in ppc_linux_nat.c

Also from /usr/include/sys/ptrace.h:
enum __ptrace_request
{
...
  /* Return the word in the process's user area at offset ADDR.  */
  PTRACE_PEEKUSER = 3,
#define PT_READ_U PTRACE_PEEKUSER
...
  /* Write the word DATA into the process's user area at offset ADDR.
*/
  PTRACE_POKEUSER = 6,
#define PT_WRITE_U PTRACE_POKEUSER
...

Even though the man pages says PTRACE_PEEKUSR and PTRACE_POKEUSR