linux-kernel - [PATCH v3 0/4] x86/fpu: Reduce unnecessary FNINIT and MXCSR usage

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Message-Id: <cover.1611205691.git.luto@kernel.org>
Date:   Wed, 20 Jan 2021 21:09:47 -0800
From:   Andy Lutomirski <luto@...nel.org>
To:     x86@...nel.org
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Krzysztof Mazur <krzysiek@...lesie.net>,
        Krzysztof Olędzki <ole@....pl>,
        Arnd Bergmann <arnd@...db.de>,
        Andy Lutomirski <luto@...nel.org>
Subject: [PATCH v3 0/4] x86/fpu: Reduce unnecessary FNINIT and MXCSR usage

This series fixes two regressions: a boot failure on AMD K7 and a
performance regression on everything.

I did a double-take here -- the regressions were reported by different
people, both named Krzysztof :)

Changes from v2:
 - Tidy up the if statements (Sean)
 - Changelog and comment improvements (Boris)

Changes from v1:
 - Fix MMX better -- MMX really does need FNINIT.
 - Improve the EFI code.
 - Rename the KFPU constants.
 - Changelog improvements.

Andy Lutomirski (4):
  x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state
  x86/mmx: Use KFPU_387 for MMX string operations
  x86/fpu: Make the EFI FPU calling convention explicit
  x86/fpu/64: Don't FNINIT in kernel_fpu_begin()

 arch/x86/include/asm/efi.h     | 24 ++++++++++++++++++++----
 arch/x86/include/asm/fpu/api.h | 27 +++++++++++++++++++++++++--
 arch/x86/kernel/fpu/core.c     |  9 +++++----
 arch/x86/lib/mmx_32.c          | 20 +++++++++++++++-----
 arch/x86/platform/efi/efi_64.c |  4 ++--
 5 files changed, 67 insertions(+), 17 deletions(-)

-- 
2.29.2