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

Hi,

> 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. 

I don't see the problem since we can pass up to 6 parameters on the i386 
architecture. The extra argument will be passed on using the stack as the 
other arguments do because of the asmlinkage directive. Using a structure 
slows everything down too much; if you can use the stack I think it's 
better to do so. What about that PIC?

> Secondly, the implementation should be in kernel/ptrace.c not under
> i386, we're trying to stop doing that.

The implementation is already in kernel/ptrace.c, only the usage lives 
under the arch-dependent directories since there the sys_ptrace entries 
are located.

> 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.

mmm... I thought it would be convenient to use ptrace for all the trace 
work.

Frank.