From mboxrd@z Thu Jan 1 00:00:00 1970 From: sboyd@codeaurora.org (Stephen Boyd) Date: Fri, 08 Nov 2013 10:51:21 -0800 Subject: [PATCH] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions In-Reply-To: <20131108165437.GM16735@n2100.arm.linux.org.uk> References: <1383852042-10780-1-git-send-email-sboyd@codeaurora.org> <20131108115004.GH28304@ns203013.ovh.net> <20131108165437.GM16735@n2100.arm.linux.org.uk> Message-ID: <527D32A9.2060603@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 11/08/13 08:54, Russell King - ARM Linux wrote: > On Fri, Nov 08, 2013 at 12:50:04PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote: >> On 19:34 Thu 07 Nov , Rob Herring wrote: >>> On Thu, Nov 7, 2013 at 1:20 PM, Stephen Boyd wrote: >>>> If we're running on a v7 ARM CPU, detect if the CPU supports the >>>> sdiv/udiv instructions and replace the signed and unsigned >>>> division library functions with an sdiv/udiv instruction. >>> [snip] >>> >>>> diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile >>>> index bd454b0..6ed6496 100644 >>>> --- a/arch/arm/lib/Makefile >>>> +++ b/arch/arm/lib/Makefile >>>> @@ -15,6 +15,9 @@ lib-y := backtrace.o changebit.o csumipv6.o csumpartial.o \ >>>> io-readsb.o io-writesb.o io-readsl.o io-writesl.o \ >>>> call_with_stack.o >>>> >>>> +lib-$(CONFIG_CPU_V7) += div-v7.o >>>> +CFLAGS_div-v7.o := -march=armv7-a >>> Won't this fail to build if the compiler doesn't have armv7-a support. >>> Perhaps we don't care about compilers that old. >> use the propoer compiler to compile a armv7 kernel > It's probably about time to get rid of the conditionals for this in > the main arch/arm/Makefile actually - some of those date back some > 10 or so years. That's something for the v3.14 merge window. I'll take that as an endorsement for not falling back to -march=armv5t -Wa,-march=armv7-a like is done in arch/arm/Makefile. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation