From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from merlin.infradead.org ([205.233.59.134]:38014 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727845AbfGVVMY (ORCPT ); Mon, 22 Jul 2019 17:12:24 -0400 Date: Mon, 22 Jul 2019 23:12:10 +0200 From: Peter Zijlstra Subject: Re: [PATCH 2/5] x86_64, -march=native: POPCNT support Message-ID: <20190722211210.GN6698@worktop.programming.kicks-ass.net> References: <20190722202723.13408-1-adobriyan@gmail.com> <20190722202723.13408-2-adobriyan@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190722202723.13408-2-adobriyan@gmail.com> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Alexey Dobriyan 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 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 > --- > 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.