On 6/5/20 3:47 AM, Alexey Brodkin wrote: > Hi Eugeniy, > > A couple of minor notes below. > >> -----Original Message----- >> From: Eugeniy Paltsev <eugeniy.palt...@synopsys.com> >> Sent: Thursday, June 4, 2020 8:39 PM >> To: linux-snps-...@lists.infradead.org; Vineet Gupta <vgu...@synopsys.com> >> Cc: linux-kernel@vger.kernel.org; Alexey Brodkin <abrod...@synopsys.com>; >> Eugeniy Paltsev >> <palt...@synopsys.com> >> Subject: [PATCH v2 1/4] ARC: allow to override default mcpu compiler flag >> >> Kernel builds set their own default -mcpu for a given ISA build. > > We used to use a default "-mcpu" per ARC ISA version (one for ARCompact > and one for ARCv2). > >> But that gets in the way of "custom" -mcpu flags from propagating >> into kernel build. > > But with more versions of CPUs & SoCs becoming available we want to > be able to fine-tune generated code more precise. > >> This will also be used in next patches for HSDK-4xD board support which >> uses a different -mcpu to effect dual issue scheduling. > > "...for utilization of the new CPU's dual-issue capabilities"? > >> +++ b/arch/arc/Makefile >> @@ -10,8 +10,25 @@ CROSS_COMPILE := $(call cc-cross-prefix, arc-linux- >> arceb-linux-) >> endif >> >> cflags-y += -fno-common -pipe -fno-builtin -mmedium-calls -D__linux__ >> -cflags-$(CONFIG_ISA_ARCOMPACT) += -mA7 >> -cflags-$(CONFIG_ISA_ARCV2) += -mcpu=hs38 >> + >> +tune-mcpu-def-$(CONFIG_ISA_ARCOMPACT) := -mA7 > > I'd suggest to either swap "-mA7" which is being obsoleted with "-mcpu=arc700" > right here or as a separate change, otherwise we may soon get ATC700 builds > broken with newer compilers.
FWIW I've added a modified variant of this patch to for-curr as we need it for ongoing ARC64 port as well. -Vineet
