From: John Baldwin <jhb@FreeBSD.org>
To: Simon Marchi <simark@simark.ca>, gdb-patches@sourceware.org
Subject: Re: [PATCH v4 02/13] core: Support fetching TARGET_OBJECT_X86_XSAVE_LAYOUT from architectures.
Date: Tue, 11 Apr 2023 09:06:15 -0700 [thread overview]
Message-ID: <a729ad80-ec25-66ab-634f-21f81a249cc8@FreeBSD.org> (raw)
In-Reply-To: <0a1d7dee-3d2f-787a-133b-64fc3e7e2032@simark.ca>
On 4/10/23 6:49 PM, Simon Marchi wrote:
> On 4/10/23 16:42, John Baldwin wrote:
>> On 4/6/23 12:28 PM, Simon Marchi wrote:
>>> On 3/17/23 21:08, John Baldwin wrote:
>>> I have yet to see how this is going to be implemented (in subsequent
>>> patches), but I wonder if we really need to pass use readbuf / offset /
>>> len in this API. Wouldn't it be possible to pass a pointer or reference
>>> to an x86_xsave_layout object, and have the arch fill it? I understand
>>> that this matches the taret_read interface (we have to shoehorn the
>>> x86_xsave_layout through that interface), but I don't think it needs to
>>> propagate to the gdbarch method.
>>
>> Hmm, passing down the readbuf, offset, len fields is consistent with other
>> gdbarch methods called from core_target::xfer_partial such as
>> gdbarch_core_xfer_shared_libraries and gdbarch_core_xfer_siginfo.
>>
>> That said, it would simplify the implementation in the architectures if
>> core_target::xfer_partial handled the partial reads and always read the
>> full thing from the gdbarch. In particular unlike the other above methods,
>> the thing being read is a fixed size. I'll make that change as I think
>> it will be nicer, thanks.
>
> I looked at these other methods and came to the same conclusion as you.
> For gdbarch_core_xfer_siginfo it doesn't really introduce any extra
> complexity, because we just pass down the offset/len parameters to
> bfd_get_section_contents. For gdbarch_core_xfer_shared_libraries,
> seeing that the sole implementation (windows_core_xfer_shared_libraries)
> just re-generates the whole XML string every time, I think we could
> simplify its interface as well, making it return just an std::string,
> and handle the partial read case in the target. Not important for what
> you're doing, I'm just thinking out loud.
>
> But now it makes me wonder what really belongs as an object in the
> xfer_partial interface, versus what belongs as just a regular target
> method. Clearly, the xfer partial interface is good to transfer some
> raw data where the transferred size can be smaller than expected. Like
> when you make a read/write syscall. But if the goal is to transfer a
> structure from one side of GDB to the other (like we do with
> x86_xsave_layout), wouldn't it be simpler to have a normal target
> method that returns that struct?
Yes. I guess I had been thinking of trying to work within existing
target methods vs adding a new one (especially a new one that is
architecture-specific). However, a new vtable entry in the target
class is probably cheap, so I'm happy to add a new target method instead
if you think that is better.
--
John Baldwin
next prev parent reply other threads:[~2023-04-11 16:06 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-18 1:08 [PATCH v4 00/13] Handle variable XSAVE layouts John Baldwin
2023-03-18 1:08 ` [PATCH v4 01/13] x86: Add an x86_xsave_layout structure to handle " John Baldwin
2023-03-28 11:35 ` George, Jini Susan
2023-04-10 19:28 ` John Baldwin
2023-04-06 19:09 ` Simon Marchi
2023-04-10 20:03 ` John Baldwin
2023-04-11 1:19 ` Simon Marchi
2023-04-11 14:23 ` Pedro Alves
2023-04-11 16:02 ` John Baldwin
2023-03-18 1:08 ` [PATCH v4 02/13] core: Support fetching TARGET_OBJECT_X86_XSAVE_LAYOUT from architectures John Baldwin
2023-04-06 19:28 ` Simon Marchi
2023-04-10 20:42 ` John Baldwin
2023-04-11 1:49 ` Simon Marchi
2023-04-11 16:06 ` John Baldwin [this message]
2023-04-11 16:21 ` Simon Marchi
2023-04-11 23:59 ` John Baldwin
2023-03-18 1:08 ` [PATCH v4 03/13] nat/x86-cpuid.h: Add x86_cpuid_count wrapper around __get_cpuid_count John Baldwin
2023-04-06 19:33 ` Simon Marchi
2023-04-10 20:49 ` John Baldwin
2023-04-11 1:49 ` Simon Marchi
2023-03-18 1:08 ` [PATCH v4 04/13] x86 nat: Add helper functions to save the XSAVE layout for the host John Baldwin
2023-04-06 19:40 ` Simon Marchi
2023-04-10 21:00 ` John Baldwin
2023-04-11 1:51 ` Simon Marchi
2023-03-18 1:08 ` [PATCH v4 05/13] gdb: Update x86 FreeBSD architectures to support XSAVE layouts John Baldwin
2023-04-06 19:54 ` Simon Marchi
2023-04-10 21:02 ` John Baldwin
2023-04-11 1:55 ` Simon Marchi
2023-03-18 1:08 ` [PATCH v4 06/13] gdb: Support XSAVE layouts for the current host in the FreeBSD x86 targets John Baldwin
2023-04-06 20:18 ` Simon Marchi
2023-04-10 21:27 ` John Baldwin
2023-04-11 2:23 ` Simon Marchi
2023-04-11 16:19 ` John Baldwin
2023-04-11 16:46 ` Simon Marchi
2023-04-11 21:37 ` John Baldwin
2023-04-11 22:35 ` John Baldwin
2023-04-12 14:35 ` Simon Marchi
2023-03-18 1:08 ` [PATCH v4 07/13] gdb: Update x86 Linux architectures to support XSAVE layouts John Baldwin
2023-04-07 1:43 ` Simon Marchi
2023-04-10 21:29 ` John Baldwin
2023-03-18 1:09 ` [PATCH v4 08/13] gdb: Support XSAVE layouts for the current host in the Linux x86 targets John Baldwin
2023-04-07 1:54 ` Simon Marchi
2023-03-18 1:09 ` [PATCH v4 09/13] gdb: Use x86_xstate_layout to parse the XSAVE extended state area John Baldwin
2023-04-07 2:13 ` Simon Marchi
2023-04-10 21:40 ` John Baldwin
2023-03-18 1:09 ` [PATCH v4 10/13] gdbserver: Add a function to set the XSAVE mask and size John Baldwin
2023-04-12 15:08 ` Simon Marchi
2023-04-27 17:24 ` John Baldwin
2023-03-18 1:09 ` [PATCH v4 11/13] gdbserver: Refactor the legacy region within the xsave struct John Baldwin
2023-04-12 18:34 ` Simon Marchi
2023-04-27 19:51 ` John Baldwin
2023-03-18 1:09 ` [PATCH v4 12/13] gdbserver: Read offsets of the XSAVE extended region via CPUID John Baldwin
2023-04-11 14:46 ` Pedro Alves
2023-04-11 16:25 ` John Baldwin
2023-04-12 19:11 ` Simon Marchi
2023-04-12 21:07 ` John Baldwin
2023-04-13 15:07 ` Simon Marchi
2023-03-18 1:09 ` [PATCH v4 13/13] x86: Remove X86_XSTATE_SIZE and related constants John Baldwin
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=a729ad80-ec25-66ab-634f-21f81a249cc8@FreeBSD.org \
--to=jhb@freebsd.org \
--cc=gdb-patches@sourceware.org \
--cc=simark@simark.ca \
/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).