Re: No PTRACE_READDATA for archs other than SPARC?

["David S. Miller" <davem@redhat.com>]

   From: Pradeep Padala <ppadala@cise.ufl.edu>
   Date: Sun, 19 May 2002 23:08:36 -0400 (EDT)

      I was trying to understand ptrace code in kernel. It seems there's
   no PTRACE_READDATA for architectures other than sparc and sparc64.
   There's a function named ptrace_readdata() in kernel/ptrace.c but I
   couldn't find a way to invoke it from user space. Is the feature
   missing? or Is it intended?

Only Sparc implements this, that is correct.

If other platforms added PTRACE_READDATA support, they would
also need to add some way to do a feature test for it's presence
so that GDB and other debugging code could actually make use
of it portably.

      Another thing I noticed, the prototype for do_ptrace() in
      arch/sparc/kernel/ptrace.c is
   
      asmlinkage void do_ptrace(struct pt_regs *regs)
   
      I thought it should be some thing like
      asmlinkage int sys_ptrace(long request, long pid, long addr, long
   data)

The return values are set directly in the user's pt_regs.