RE: [PATCH v3 00/13] Handle variable XSAVE layouts

["Willgerodt, Felix" <felix.willgerodt@intel.com>]

Hi John,

I saw them but I only skimmed over them a bit so far, sorry.
I didn't have any direct comments apart from what I already
stated for earlier versions, so I didn't answer.

I couldn't apply the patches unfortunately. For some reason git
tells me formatting is off. Not sure if the fault is on my end or on
yours. But I tried a bit on my side to no avail.
So I couldn't test them on some of our internal targets.

Yes you can remove the Intel changelogs.

Regards,
Felix

> -----Original Message-----
> From: John Baldwin <jhb@FreeBSD.org>
> Sent: Mittwoch, 18. Mai 2022 23:53
> To: gdb-patches@sourceware.org
> Cc: Willgerodt, Felix <felix.willgerodt@intel.com>
> Subject: Re: [PATCH v3 00/13] Handle variable XSAVE layouts
> 
> Felix,
> 
> Did you have any thoughts on this series?  I had tried to cc you on it,
> but that didn't succeed it seems.  This does have some conflicts with
> your AMX series, but those should be minor to resolve.
> 
> On 5/3/22 2:05 PM, John Baldwin wrote:
> > Changes since V2:
> >
> > - Pulled in some of the changes from Intel's branch Felix pointed me
> >    at, in particular gdbserver support.  However, relative to that
> >    branch these patches make the following changes:
> >
> >    - The i387_* structs and class remain in gdbserver/i387-fp.cc
> >      rather than moving to gdbsupport/.
> >
> >    - Rather than invoking cpuid each time an XSAVE area is parsed,
> >      the x86_xsave_layout structure is used to hold offsets and
> >      CPUID is only invoked the first time NT_X86_XSTATE is probed
> >      with the offsets cached for later use.
> >
> >    - I did not update the ChangeLog bits of these log messages, but
> >      probably they can be dropped for the Intel commits as GDB
> >      commits generally do not include these now?
> >
> > - Added Linux support both for gdbarches and the x86 native targets.
> >    I wasn't sure if PT_GETREGSET on Linux provides a way to query the
> >    size of the XSAVE register set (on FreeBSD PT_GETREGSET returns
> >    the register set's size in iov_len of the passed-in iovec if the
> >    original iovec has a NULL pointer and zero length), so I used
> >    cpuid leaf 0xd subleaf 0x0 to query the size of the register set
> >    for the native targets as well as for the Linux gdbserver support.
> >
> > Note that this still depends on the size and xcr0 mask heuristic for
> > Linux and FreeBSD core dumps to determine the layout (and I have not
> > added any additional layouts as I wasn't sure if Jini was intending to
> > add additional AMD-specific layouts).  I'd kind of like to land this
> > series before doing a followup to flesh out a new core dump note.
> >
> > I think for the new core dump note what I would propose is a simple
> > array of CPUID results for sub-leaves of the 0xd leaf (as a
> > NT_X86_XSTATE_CPUID or the like) where each entry in the array
> > contained the subleaf as well as eax, ebx, ecx, and edx results.  This
> > note might even eventually permit handling "compact" XSTATE in future
> > core dumps rather than only "standard".
> >
> > I have tested this on both an AMD Ryzen 9 5900X and Intel Core
> > i7-8650U on FreeBSD/amd64 as well as on a Linux/x86-64 VM on the Intel
> > system.  I also tested FreeBSD/i386 in a VM on the AMD system.
> >
> > Aleksandar Paunovic (2):
> >    gdbserver: Refactor the legacy region within the xsave struct
> >    gdbserver: Read offsets of the XSAVE extended region via CPUID
> >
> > John Baldwin (11):
> >    x86: Add an x86_xsave_layout structure to handle variable XSAVE
> >      layouts.
> >    core: Support fetching TARGET_OBJECT_X86_XSAVE_LAYOUT from
> >      architectures.
> >    nat/x86-cpuid.h: Add x86_cpuid_count wrapper around __get_cpuid_count.
> >    x86 nat: Add helper functions to save the XSAVE layout for the host.
> >    gdb: Update x86 FreeBSD architectures to support XSAVE layouts.
> >    gdb: Support XSAVE layouts for the current host in the FreeBSD x86
> >      targets.
> >    gdb: Update x86 Linux architectures to support XSAVE layouts.
> >    gdb: Support XSAVE layouts for the current host in the Linux x86
> >      targets.
> >    gdb: Use x86_xstate_layout to parse the XSAVE extended state area.
> >    gdbserver: Add a function to set the XSAVE mask and size.
> >    x86: Remove X86_XSTATE_SIZE and related constants.
> >
> >   gdb/amd64-fbsd-nat.c       |  40 +--
> >   gdb/amd64-fbsd-tdep.c      |   8 +-
> >   gdb/amd64-linux-nat.c      |   6 +-
> >   gdb/amd64-linux-tdep.c     |   8 +-
> >   gdb/configure.nat          |   8 +-
> >   gdb/corelow.c              |  22 ++
> >   gdb/gdbarch-components.py  |  13 +
> >   gdb/gdbarch-gen.h          |  10 +
> >   gdb/gdbarch.c              |  32 +++
> >   gdb/i386-fbsd-nat.c        |  39 +--
> >   gdb/i386-fbsd-tdep.c       |  37 ++-
> >   gdb/i386-fbsd-tdep.h       |   6 +
> >   gdb/i386-linux-nat.c       |   8 +-
> >   gdb/i386-linux-tdep.c      |  34 ++-
> >   gdb/i386-linux-tdep.h      |   6 +
> >   gdb/i386-tdep.c            |  36 ++-
> >   gdb/i386-tdep.h            |   3 +
> >   gdb/i387-tdep.c            | 493 ++++++++++++++++++++++++-------------
> >   gdb/i387-tdep.h            |   8 +
> >   gdb/nat/x86-cpuid.h        |  27 ++
> >   gdb/nat/x86-xstate.c       |  65 +++++
> >   gdb/nat/x86-xstate.h       |  35 +++
> >   gdb/target.h               |   2 +
> >   gdb/x86-fbsd-nat.c         |  51 ++++
> >   gdb/x86-fbsd-nat.h         |  29 ++-
> >   gdb/x86-linux-nat.c        |  33 +++
> >   gdb/x86-linux-nat.h        |  11 +
> >   gdbserver/configure.srv    |  12 +-
> >   gdbserver/i387-fp.cc       | 312 ++++++++++++++---------
> >   gdbserver/i387-fp.h        |   2 +-
> >   gdbserver/linux-x86-low.cc |  10 +-
> >   gdbsupport/x86-xstate.h    |  69 ++++--
> >   32 files changed, 1067 insertions(+), 408 deletions(-)
> >   create mode 100644 gdb/nat/x86-xstate.c
> >   create mode 100644 gdb/nat/x86-xstate.h
> >
> 
> 
> --
> John Baldwin
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