Commit 0bdd6e74 authored by Eugeniy Paltsev's avatar Eugeniy Paltsev Committed by Vineet Gupta
Browse files

ARC: build: allow users to specify -mcpu 



kernel build system used to add -mcpu for each ARC ISA as default.
These days there are versions and varaints of ARC HS cores some of which
have specific -mcpu options to fine tune / optimize generated code.

So allow users/external build systems to specify their own -mcpu

This will be used in future patches for HSDK-4xD board support which
uses specific -mcpu to utilize dual issue scheduling of the core.

Signed-off-by: default avatarEugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
[abrodkin/vgupta: rewrote changelog]
parent 97d0b5d0

arch/arc/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -170,6 +170,15 @@ config ARC_CPU_HS 


endchoice



config ARC_TUNE_MCPU

	string "Override default -mcpu compiler flag"

	default ""

	help

	  Override default -mcpu=xxx compiler flag (which is set depending on

	  the ISA version) with the specified value.

	  NOTE: If specified flag isn't supported by current compiler the

	  ISA default value will be used as a fallback.



config CPU_BIG_ENDIAN

	bool "Enable Big Endian Mode"

	help

arch/arc/Makefile

+19 −2
Original line number Diff line number Diff line
@@ -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

tune-mcpu-def-$(CONFIG_ISA_ARCV2)	:= -mcpu=hs38



ifeq ($(CONFIG_ARC_TUNE_MCPU),"")

cflags-y				+= $(tune-mcpu-def-y)

else

tune-mcpu				:= $(shell echo $(CONFIG_ARC_TUNE_MCPU))

tune-mcpu-ok 				:= $(call cc-option-yn, $(tune-mcpu))

ifeq ($(tune-mcpu-ok),y)

cflags-y				+= $(tune-mcpu)

else

# The flag provided by 'CONFIG_ARC_TUNE_MCPU' option isn't known by this compiler

# (probably the compiler is too old). Use ISA default mcpu flag instead as a safe option.

$(warning ** WARNING ** CONFIG_ARC_TUNE_MCPU flag '$(tune-mcpu)' is unknown, fallback to '$(tune-mcpu-def-y)')

cflags-y				+= $(tune-mcpu-def-y)

endif

endif





ifdef CONFIG_ARC_CURR_IN_REG

# For a global register defintion, make sure it gets passed to every file

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