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From: Peter Zijlstra <peterz@infradead.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	hpa@zytor.com, linux-kernel@vger.kernel.org, x86@kernel.org,
	linux-kbuild@vger.kernel.org, yamada.masahiro@socionext.com,
	michal.lkml@markovi.net
Subject: Re: [PATCH 2/5] x86_64, -march=native: POPCNT support
Date: Mon, 22 Jul 2019 23:12:10 +0200	[thread overview]
Message-ID: <20190722211210.GN6698@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20190722202723.13408-2-adobriyan@gmail.com>

On Mon, Jul 22, 2019 at 11:27:20PM +0300, Alexey Dobriyan wrote:
> Detect POPCNT instruction support and inline hweigth*() functions
> if it is supported by CPU.
> 
> Detect POPCNT at boot time and conditionally refuse to boot.
> 
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> ---
>  arch/x86/include/asm/arch_hweight.h           | 24 +++++++++++++++++++
>  arch/x86/include/asm/segment.h                |  1 +
>  arch/x86/kernel/verify_cpu.S                  |  8 +++++++
>  arch/x86/lib/Makefile                         |  5 +++-
>  .../drm/i915/display/intel_display_power.c    |  2 +-
>  drivers/misc/sgi-gru/grumain.c                |  2 +-
>  fs/btrfs/tree-checker.c                       |  4 ++--
>  include/linux/bitops.h                        |  2 ++
>  lib/Makefile                                  |  2 ++
>  scripts/kconfig/cpuid.c                       |  7 ++++++
>  scripts/march-native.sh                       |  2 ++
>  11 files changed, 54 insertions(+), 5 deletions(-)

*WHY* ?

AFAICT this just adds lines and complexity and wins aboslutely nothing.

  reply	other threads:[~2019-07-22 21:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-22 20:27 [PATCH 1/5] x86_64: -march=native support Alexey Dobriyan
2019-07-22 20:27 ` [PATCH 2/5] x86_64, -march=native: POPCNT support Alexey Dobriyan
2019-07-22 21:12   ` Peter Zijlstra [this message]
2019-07-22 21:15     ` Alexey Dobriyan
2019-07-22 21:27       ` Alexey Dobriyan
2019-07-23  7:20       ` Peter Zijlstra
2019-07-23 20:04         ` Alexey Dobriyan
2019-07-22 20:27 ` [PATCH 3/5] x86_64, -march=native: REP MOVSB support Alexey Dobriyan
2019-07-22 20:27 ` [PATCH 4/5] x86_64, -march=native: REP STOSB support Alexey Dobriyan
2019-07-22 20:27 ` [PATCH 5/5] x86_64, -march=native: MOVBE support Alexey Dobriyan
  -- strict thread matches above, loose matches on Subject: below --
2019-07-04 20:47 [PATCH 1/5] x86_64: -march=native support Alexey Dobriyan
2019-07-04 20:47 ` [PATCH 2/5] x86_64, -march=native: POPCNT support Alexey Dobriyan

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