Re: [rfc] Query Red Boot's i386 CPU id

[Daniel Jacobowitz <drow at mvista dot com>]

On Wed, Aug 28, 2002 at 05:31:46PM -0400, Andrew Cagney wrote:
> Comments on how this was implemented, and what, if anything, could be 
> integrated into GDB, welcome.


> +/* NOTE: cagney/2001-11-17:
> +
> +   This module uses the [remote protocol] target_query ("qCPUID")
> +   method to extract the i386 CPU information.  It then takes that
> +   information and uses it to do a lookup on a local file
> +   ``cpuid-i386''.
> +
> +   Thanks to a botched initial thread query mechanism, using anything
> +   starting with ``qC'' is dangerous.  Since qCPUID does this, it
> +   won't interact well with targets that recognize the exiting ``qC''
> +   query.  Sigh.
> +
> +   One possible alternative to this qCPUID mechanis would be to plant
> +   a CPUID instruction in the target memory, execute it, and then
> +   examine the result.  This probably isn't pratical since it depends
> +   in being able to execute code in the target.
> +
> +   This file adds the command ``info cpu''.  Beware of the existing
> +   commands ``{set,show} {processor,architecture}''.
> +
> +   This file uses a target_post_open_hook() mechanism to hook into the
> +   target open (and report the CPUID on an initial connect).  Per the
> +   comment in the file "target.h", what really should be happening is
> +   a core_gdb_open() function should be calling the hook.  */

That comment is pretty thorough about my concerns :)  Gdbserver doesn't
support qC yet (just realized a moment ago that it probably should). 
But qCPUID really doesn't work with that.  I bet there's deployed
RedBoot stubs that have this problem?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer