Re: [PATCH] ptrace PTRACE_READDATA/WRITEDATA, kernel 2.5.62

[Daniel Jacobowitz <dan@debian.org>]

On Mon, Feb 24, 2003 at 03:05:14PM +0100, fcorneli@elis.rug.ac.be wrote:
> Hi,
> 
> I ported some generic SunOS ptrace requests from my 2.4 exptrace kernel 
> patch to the 2.5 tree. The PTRACE_READDATA/WRITEDATA requests have been 
> available for a long time for the sparc architecture but I think they're 
> also very useful on the i386 arch since PTRACE_PEEKDATA/POKEDATA are way 
> too slow when handling large data blocks.

FYI Frank, three things.  First of all, I really don't like the
interface of adding a second address to ptrace; I believe it interferes
with PIC on x86, since IIRC the extra argument would go in %ebx.  The
BSDs have a nice interface involving passing a request structure. 
Secondly, the implementation should be in kernel/ptrace.c not under
i386, we're trying to stop doing that.

Thirdly, I was going to do this, but I ended up making GDB use pread64
on /dev/mem instead.  It works with no kernel modifications, and is
just as fast.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer