linux-kernel - [patch V4 00/65] x86/fpu: Spring cleaning and PKRU sanitizing

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Message-Id: <20210623120127.327154589@linutronix.de>
Date:   Wed, 23 Jun 2021 14:01:27 +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>,
        "Chang Seok Bae" <chang.seok.bae@...el.com>,
        Megha Dey <megha.dey@...ux.intel.com>,
        Oliver Sang <oliver.sang@...el.com>
Subject: [patch V4 00/65] x86/fpu: Spring cleaning and PKRU sanitizing

The main parts of this series are:

  - 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 V3 which can be found here:

     https://lore.kernel.org/r/20210618141823.161158090@linutronix.de

Changes vs. V3:

  - Dropped the two bugfixes which are applied already and rebased on top

  - Addressed review comments (Andy, Boris)

    Patches: 13, 35, 36, 37, 46, 58, 62, 63

  - Fixed the math-emu fallout which I had stashed safely on the 32bit
    testbox (Boris)

    Patch: 28

  - Picked up tags

Thanks to everyone for review, feedback and testing (various teams
@Intel).

Note: I've not picked up any tested-by tags. It would be nice to have
them on this hopefully final version.

Thanks,

	tglx
---
 arch/x86/events/intel/lbr.c          |    6 
 arch/x86/include/asm/fpu/internal.h  |  202 ++++------
 arch/x86/include/asm/fpu/xstate.h    |   78 +++-
 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           |  282 +++++++--------
 arch/x86/kernel/fpu/init.c           |   15 
 arch/x86/kernel/fpu/regset.c         |  223 ++++++------
 arch/x86/kernel/fpu/signal.c         |  419 ++++++++++------------
 arch/x86/kernel/fpu/xstate.c         |  645 +++++++++++++----------------------
 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/math-emu/fpu_proto.h        |    2 
 arch/x86/math-emu/load_store.c       |    2 
 arch/x86/math-emu/reg_ld_str.c       |    2 
 arch/x86/mm/extable.c                |    2 
 arch/x86/mm/fault.c                  |    2 
 arch/x86/mm/pkeys.c                  |   22 -
 include/linux/pkeys.h                |    4 
 26 files changed, 1037 insertions(+), 1166 deletions(-)