From: Antoine Tremblay <antoine.tremblay@ericsson.com>
To: Pedro Alves <palves@redhat.com>
Cc: "Marcin Kościelnicki" <koriakin@0x04.net>,
"Antoine Tremblay" <antoine.tremblay@ericsson.com>,
gdb-patches@sourceware.org, qiyaoltc@gmail.com
Subject: Re: [PATCH v3] Enable tracing of pseudo-registers on ARM
Date: Wed, 24 Feb 2016 18:55:00 -0000 [thread overview]
Message-ID: <wwokfuwi7xal.fsf@ericsson.com> (raw)
In-Reply-To: <56CDF792.3040604@redhat.com>
Pedro Alves writes:
> On 02/24/2016 06:20 PM, Marcin KoÅcielnicki wrote:
>> On 24/02/16 19:11, Pedro Alves wrote:
>>> On 02/22/2016 04:51 PM, Antoine Tremblay wrote:
>>>>
>
>>>> While looking at fixing this for all the archs involved it would be
>>>> much simpler to test if gdbserver would make use of it.
>>>>
>>>> As it is now, I'm concerned that calling gdbarch_remote_register_number
>>>> in ax_reg, ax_mask_reg could break things if the arch already considers
>>>> the gdb raw -> target raw mapping like s390 and x86 do already (I'm not
>>>> 100% sure the mapping is already ok)?
>>>
>>> WDTM? Where do they do this already?
>>
>> FWIW, I failed to look at the numbering used when I wrote the x86 and
>> s390 ax functions, so they're most likely wrong (I just copied the
>> regnum computation logic from pseudo_read/write, which uses gdb
>> numbers). s390 hasn't landed yet, so it's only x86 that you'd have to
>> fix now (and mips, I think, but that doesn't support tracepoints yet...).
>
> I don't think there's anything that needs fixing in the i386 implementation.
>
> The x86 implementation maps gdb pseudo register numbers to whatever
> raw gdb registers back the former up, like:
>
> ax_reg_mask (ax, I387_FSTAT_REGNUM (tdep));
>
> That OK.
>
> The trouble is that in the end we send gdb numbers to the target in the
> ax, instead of tdesc/remote numbers.
>
> We never noticed because gdbserver always collects all raw registers
> anyway.
>
> Seems to me that the fix is to make ax_reg / ax_reg_mask take gdb raw
> numbers as input (as it does today), and then make it map those to
> tdesc/remote number just before it puts the reg number in the agent
> expression bytecode / reg mask. And that covers all archs.
>
>>
>> Testing this is possible if you write some conditions that involve
>> reading pseudo-registers (since ax_pseudo_register_push_stack will be
>> called), the problem is that I only implemented
>> ax_pseudo_register_collect for x86...
>>
>> Are you going to make some higher-level patch that will magically fix it
>> for my s390 patch, or do I have to fix that on my own?
>
> I haven't memorized your s390 patch :-) but there's probably nothing to
> do on the s390-specific bits.
>
The only requirement for this to work properly is that the arch uses
tdesc_use_registers, otherwise the default mapping function to tdesc is
identity to GDB numbers.
s390 uses that so it should be fine.
Thanks,
Antoine
next prev parent reply other threads:[~2016-02-24 18:55 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-07 17:45 [PATCH 0/4] Support tracepoints for ARM linux in GDBServer Antoine Tremblay
2016-01-07 17:45 ` [PATCH 1/4] Teach arm unwinders to terminate gracefully Antoine Tremblay
2016-02-12 14:46 ` Yao Qi
2016-02-24 17:57 ` Antoine Tremblay
2016-02-25 11:44 ` Pedro Alves
2016-02-25 13:15 ` Antoine Tremblay
2016-02-26 9:12 ` Yao Qi
2016-02-26 12:26 ` Antoine Tremblay
2016-02-26 14:25 ` Yao Qi
2016-02-26 20:10 ` Antoine Tremblay
2016-04-06 15:54 ` Yao Qi
2016-04-06 16:30 ` Pedro Alves
2016-04-07 16:33 ` Yao Qi
2016-05-04 16:24 ` Yao Qi
2016-01-07 17:45 ` [PATCH 2/4] Use the target architecture when encoding tracepoint actions Antoine Tremblay
2016-02-06 20:58 ` Marcin Kościelnicki
2016-02-11 13:02 ` Pedro Alves
2016-02-11 13:21 ` Antoine Tremblay
2016-01-07 17:45 ` [PATCH 4/4] Support tracepoints for ARM linux in GDBServer Antoine Tremblay
2016-02-08 14:45 ` Antoine Tremblay
2016-01-07 17:45 ` [PATCH 3/4] Enable tracing of pseudo-registers on ARM Antoine Tremblay
2016-02-12 15:14 ` Yao Qi
2016-02-12 15:54 ` Marcin Kościelnicki
2016-02-15 10:27 ` Yao Qi
2016-02-15 10:57 ` Pedro Alves
2016-02-15 14:46 ` [PATCH v2] " Antoine Tremblay
2016-02-19 16:33 ` Antoine Tremblay
2016-02-19 19:29 ` [PATCH v3] " Antoine Tremblay
2016-02-19 20:06 ` [PATCH v4] " Antoine Tremblay
2016-02-19 20:22 ` [PATCH v3] " Pedro Alves
2016-02-19 20:32 ` Antoine Tremblay
2016-02-22 11:51 ` Yao Qi
2016-02-22 16:51 ` Antoine Tremblay
2016-02-24 18:11 ` Pedro Alves
2016-02-24 18:21 ` Marcin Kościelnicki
2016-02-24 18:33 ` Pedro Alves
2016-02-24 18:55 ` Antoine Tremblay [this message]
2016-02-24 19:02 ` Pedro Alves
2016-02-24 19:02 ` Antoine Tremblay
2016-02-23 19:34 ` Antoine Tremblay
2016-02-24 18:20 ` Pedro Alves
2016-02-24 18:47 ` Antoine Tremblay
2016-02-23 19:41 ` [PATCH v5] " Antoine Tremblay
2016-02-24 19:12 ` Pedro Alves
2016-02-24 19:25 ` Antoine Tremblay
2016-02-25 10:35 ` Yao Qi
2016-02-25 15:33 ` [PATCH v6] " Antoine Tremblay
2016-02-25 17:59 ` Pedro Alves
2016-02-25 18:19 ` Antoine Tremblay
2016-02-26 8:34 ` Yao Qi
2016-02-26 13:00 ` Antoine Tremblay
2016-02-26 13:03 ` [PATCH v7] " Antoine Tremblay
2016-02-26 14:14 ` Yao Qi
2016-02-26 14:57 ` Antoine Tremblay
2016-02-26 14:59 ` [PATCH v8] " Antoine Tremblay
2016-02-26 15:57 ` Yao Qi
2016-02-26 17:45 ` Antoine Tremblay
2016-01-11 12:17 ` [PATCH 0/4] Support tracepoints for ARM linux in GDBServer Yao Qi
2016-01-11 12:56 ` Antoine Tremblay
2016-01-11 13:41 ` Yao Qi
2016-04-26 19:11 ` Antoine Tremblay
2016-04-27 8:00 ` Yao Qi
2016-04-27 12:07 ` Antoine Tremblay
2016-04-27 13:57 ` Yao Qi
2016-04-27 14:41 ` Antoine Tremblay
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=wwokfuwi7xal.fsf@ericsson.com \
--to=antoine.tremblay@ericsson.com \
--cc=gdb-patches@sourceware.org \
--cc=koriakin@0x04.net \
--cc=palves@redhat.com \
--cc=qiyaoltc@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).