linux-kernel - [patch V3 00/66] x86/fpu: Spring cleaning and PKRU sanitizing

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Message-Id: <20210618141823.161158090@linutronix.de>
Date:   Fri, 18 Jun 2021 16:18:23 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Yu-cheng Yu <yu-cheng.yu@...el.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Borislav Petkov <bp@...e.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: [patch V3 00/66] x86/fpu: Spring cleaning and PKRU sanitizing

The main parts of this series are:

  - Yet more bug fixes

  - Simplification and removal/replacement of redundant and/or
    overengineered code.

  - Name space cleanup as the existing names were just a permanent source
    of confusion.

  - Clear seperation of user ABI and kernel internal state handling.

  - Removal of PKRU from being XSTATE managed in the kernel because PKRU
    has to be eagerly restored on context switch and keeping it in sync
    in the xstate buffer is just pointless overhead and fragile.

    The kernel still XSAVEs PKRU on context switch but the value in the
    buffer is not longer used and never restored from the buffer.

    This still needs to be cleaned up, but the series is already 40+
    patches large and the cleanup of this is not a functional problem.

    The functional issues of PKRU management are fully addressed with the
    series as is.

  - Cleanup of fpu signal restore

    - Make the fast path self contained. Handle #PF directly and skip
      the slow path on any other exception as that will just end up
      with the same result that the frame is invalid. This allows
      the compiler to optimize the slow path out for 64bit kernels
      w/o ia32 emulation.

    - Reduce code duplication and unnecessary operations
      

It applies on top of

  git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git master

and is also available via git:

  git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git x86/fpu

This is a follow up to V2 which can be found here:

     https://lore.kernel.org/r/20210614154408.673478623@linutronix.de

Changes vs. V2:

  - Fixed the testing fallout (Dave, Kan)

  - Fixed a few issues found by myself when going through the lot
    with a fine comb, especially MXCSR handling

  - Drop the FNSAVE optimizations

  - Cleanup of signal restore

  - Addressed review comments, mostly comments and a hopefully better
    naming scheme which now just uses the instruction names and
    consolidates everything else on save/restore so it's close to the way
    how the hardware works.

  - A few cleanups and simplifications on the way (mostly regset related).

  - Picked up tags

With the above I'm not intending to do any further surgery on that
code at the moment, though there is still room for improvement which
can and has to be worked on when new bits are added.

Thanks,

	tglx
---
 arch/x86/events/intel/lbr.c          |    6 
 arch/x86/include/asm/fpu/internal.h  |  211 +++-------
 arch/x86/include/asm/fpu/xstate.h    |   70 ++-
 arch/x86/include/asm/pgtable.h       |   57 --
 arch/x86/include/asm/pkeys.h         |    9 
 arch/x86/include/asm/pkru.h          |   62 +++
 arch/x86/include/asm/processor.h     |    9 
 arch/x86/include/asm/special_insns.h |   14 
 arch/x86/kernel/cpu/common.c         |   34 -
 arch/x86/kernel/fpu/core.c           |  276 +++++++------
 arch/x86/kernel/fpu/init.c           |   15 
 arch/x86/kernel/fpu/regset.c         |  220 ++++++-----
 arch/x86/kernel/fpu/signal.c         |  423 +++++++++------------
 arch/x86/kernel/fpu/xstate.c         |  693 ++++++++++++++---------------------
 arch/x86/kernel/process.c            |   22 -
 arch/x86/kernel/process_64.c         |   28 +
 arch/x86/kernel/traps.c              |    5 
 arch/x86/kvm/svm/sev.c               |    1 
 arch/x86/kvm/x86.c                   |   56 +-
 arch/x86/mm/extable.c                |    2 
 arch/x86/mm/fault.c                  |    2 
 arch/x86/mm/pkeys.c                  |   22 -
 include/linux/pkeys.h                |    4 
 23 files changed, 1060 insertions(+), 1181 deletions(-)