From: Pedro Alves <palves@redhat.com>
To: "Maciej W. Rozycki" <macro@codesourcery.com>
Cc: Yao Qi <yao@codesourcery.com>, gdb-patches@sourceware.org
Subject: Re: [PATCH] MIPS: Handle the DSP registers for bare metal
Date: Tue, 30 Dec 2014 10:12:00 -0000 [thread overview]
Message-ID: <54A27A7E.4070200@redhat.com> (raw)
In-Reply-To: <alpine.DEB.1.10.1412300034430.19155@tp.orcam.me.uk>
On 12/30/2014 01:15 AM, Maciej W. Rozycki wrote:
> On Fri, 19 Dec 2014, Pedro Alves wrote:
>
>>>> > >> Took me a bit to grok this, but this is adding slack for ACXn, right?
>>> > >
>>> > > Sorry, what do you mean by "slack" here? Is it "gap" or something else?
>> >
>> > Yes, "gap".
>> >
>>> > > The offsets of DSP registers are different on linux and bare metal, so
>>> > > this patch gives the correct offset or layout to them.
>> >
>> > The proper solution for this issue is to decouple GDB's internal
>> > register numbers from the target's g/G packet layout, which is exactly
>> > what happens when you have a description -- GDB uses the offsets found
>> > in the target description. And you're touching code that is parsing a
>> > description, so the real issue should be in the target description.
> I'm not sure offhand whether the piece of patch proposed you refer to
> here is correct or not, but the overall scope of this and the other patch
> Yao has mentioned yet outstanding is support for legacy bare-metal RSP
> stubs that have no notion of target descriptions and may even predate
> GDB's support for these descriptions, and yet they want to make all
> processor registers available for inspection and modification by GDB.
> This code comes from MIPS UK and dates back to early 2000s and I think it
> would be good having it upstream so that standard GDB can talk to these
> stubs. The fixed layout of the g/G packet and corresponding p/P packet
> offsets have been set by the bare-metal SDE toolchain years ago.
The way to handle that is still through target descriptions -- if a
target doesn't send a target description, GDB maps known layouts to built-in
target descriptions. See mips_register_g_packet_guesses.
[snip interesting background info]
Thanks for all that.
--
Pedro Alves
next prev parent reply other threads:[~2014-12-30 10:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-18 13:26 Yao Qi
2014-12-18 17:28 ` Pedro Alves
2014-12-19 3:55 ` Yao Qi
2014-12-19 11:18 ` Pedro Alves
2014-12-19 13:22 ` Yao Qi
2014-12-19 15:07 ` Pedro Alves
2014-12-30 1:15 ` Maciej W. Rozycki
2014-12-30 10:12 ` Pedro Alves [this message]
2014-12-30 12:11 ` Maciej W. Rozycki
2015-01-05 11:40 ` Pedro Alves
2015-01-07 15:11 ` Maciej W. Rozycki
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