From: John Baldwin <jhb@FreeBSD.org>
To: Simon Marchi <simark@simark.ca>, gdb-patches@sourceware.org
Subject: Re: [PATCH v5 09/19] gdb: Update x86 FreeBSD architectures to support XSAVE layouts.
Date: Mon, 8 May 2023 10:33:02 -0700 [thread overview]
Message-ID: <a3f1516c-4312-2208-9443-3a6348ed58a9@FreeBSD.org> (raw)
In-Reply-To: <5ec7bbaa-6615-f1e0-8846-164789a1ccca@simark.ca>
On 5/4/23 10:20 AM, Simon Marchi wrote:
> On 5/3/23 19:45, John Baldwin wrote:
>> On 5/3/23 10:14 AM, Simon Marchi wrote:
>>>> diff --git a/gdb/i386-fbsd-tdep.h b/gdb/i386-fbsd-tdep.h
>>>> index cb991af9e49..f96c00d45eb 100644
>>>> --- a/gdb/i386-fbsd-tdep.h
>>>> +++ b/gdb/i386-fbsd-tdep.h
>>>> @@ -20,10 +20,16 @@
>>>> #ifndef I386_FBSD_TDEP_H
>>>> #define I386_FBSD_TDEP_H
>>>> +#include "gdbsupport/x86-xstate.h"
>>>> #include "regset.h"
>>>> -/* Get XSAVE extended state xcr0 from core dump. */
>>>> -extern uint64_t i386fbsd_core_read_xcr0 (bfd *abfd);
>>>> +/* Validate and fetch XSAVE extended state xcr0 and extended area
>>>> + layout from core dump. */
>>>> +uint64_t i386_fbsd_core_read_xsave_info (bfd *abfd, x86_xsave_layout &layout);
>>>
>>> I was a bit confused when I read the comment above for the first time.
>>> Can you rephrase it to make it clear that the function returns the XSAVE
>>> extended state, and fills LAYOUT?
>>>
>>> Also, what does "validate" mean, what happens if the thing we validate
>>> is not valid?
>>
>> Hmm, the intent is "Validate and fetch xcr0 and the XSAVE layout". In
>> particular, this does not return the extended state (which would be the
>> value of all the AVX registers, etc.) but instead returns only the mask of
>> enabled state (xcr0) and the layout of the extended area.
>>
>> If xcr0 does not appear valid or the section doesn't seem to have a valid
>> size (i386_set_xsave_layout returns false) then the function claims that
>> only SSE is reported by returning X86_XSTATE_SSE_MASK. That is the
>> validation that "validate" is referring to.
>
> Maybe it's the two "and" in the sentence that make it ambiguous. So,
> perhaps:
>
> Read the xcr0 value from the ABFD core file. If it appears to be valid,
> return it and fill LAYOUT with values inferred from that value.
>
> Otherwise, return X86_XSTATE_SSE_MASK as a fallback and leave LAYOUT
> untouched.
Yes, that is clearer. I've fixed it here and in the similar commit to
i386-linux-tdep.h.
--
John Baldwin
next prev parent reply other threads:[~2023-05-08 17:33 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-27 21:00 [PATCH v5 00/19] Handle variable " John Baldwin
2023-04-27 21:00 ` [PATCH v5 01/19] x86: Add an x86_xsave_layout structure to handle " John Baldwin
2023-04-27 21:00 ` [PATCH v5 02/19] gdb: Store an x86_xsave_layout in i386_gdbarch_tdep John Baldwin
2023-05-03 16:22 ` Simon Marchi
2023-05-08 16:51 ` John Baldwin
2023-04-27 21:00 ` [PATCH v5 03/19] core: Support fetching x86 XSAVE layout from architectures John Baldwin
2023-04-27 21:00 ` [PATCH v5 04/19] nat/x86-cpuid.h: Add x86_cpuid_count wrapper around __get_cpuid_count John Baldwin
2023-04-27 21:00 ` [PATCH v5 05/19] x86 nat: Add helper functions to save the XSAVE layout for the host John Baldwin
2023-04-27 21:01 ` [PATCH v5 06/19] x86-fbsd-nat: Add missing public label John Baldwin
2023-04-27 21:01 ` [PATCH v5 07/19] *-fbsd-nat: Handle null inferior in read_description John Baldwin
2023-04-27 21:01 ` [PATCH v5 08/19] *-linux-nat: " John Baldwin
2023-05-03 16:38 ` Simon Marchi
2023-05-08 17:24 ` John Baldwin
2023-04-27 21:01 ` [PATCH v5 09/19] gdb: Update x86 FreeBSD architectures to support XSAVE layouts John Baldwin
2023-05-03 17:14 ` Simon Marchi
2023-05-03 17:20 ` Simon Marchi
2023-05-03 23:45 ` John Baldwin
2023-05-04 17:20 ` Simon Marchi
2023-05-08 17:33 ` John Baldwin [this message]
2023-04-27 21:01 ` [PATCH v5 10/19] gdb: Support XSAVE layouts for the current host in the FreeBSD x86 targets John Baldwin
2023-04-27 21:01 ` [PATCH v5 11/19] gdb: Update x86 Linux architectures to support XSAVE layouts John Baldwin
2023-04-27 21:01 ` [PATCH v5 12/19] gdb: Support XSAVE layouts for the current host in the Linux x86 targets John Baldwin
2023-04-27 21:01 ` [PATCH v5 13/19] gdb: Use x86_xstate_layout to parse the XSAVE extended state area John Baldwin
2023-04-27 21:01 ` [PATCH v5 14/19] gdbserver: Add a function to set the XSAVE mask and size John Baldwin
2023-04-27 21:01 ` [PATCH v5 15/19] gdbserver: Refactor the legacy region within the xsave struct John Baldwin
2023-04-27 21:01 ` [PATCH v5 16/19] gdbserver: Clear upper ZMM registers in the right location John Baldwin
2023-05-03 17:49 ` Simon Marchi
2023-05-03 23:47 ` John Baldwin
2023-04-27 21:01 ` [PATCH v5 17/19] gdbserver: Use x86_xstate_layout to parse the XSAVE extended state area John Baldwin
2023-04-27 21:01 ` [PATCH v5 18/19] x86: Remove X86_XSTATE_SIZE and related constants John Baldwin
2023-04-27 21:01 ` [PATCH v5 19/19] gdbserver: Simplify handling of ZMM registers John Baldwin
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