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authorEugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>2020-06-04 20:39:24 +0300
committerVineet Gupta <vgupta@synopsys.com>2020-06-16 15:07:23 -0700
commit0bdd6e7428a2e8971d7c9b8e212056dd0e0001c9 (patch)
treeadee442762555c9ed478424427ca489a553f2507 /arch/arc
parent97d0b5d0b5a99871a983ca9b5c02bfde8bf73cbf (diff)
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: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> [abrodkin/vgupta: rewrote changelog]
Diffstat (limited to 'arch/arc')
-rw-r--r--arch/arc/Kconfig9
-rw-r--r--arch/arc/Makefile21
2 files changed, 28 insertions, 2 deletions
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index fddc70029727..323014149e48 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -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
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 20e9ab6cc521..2b66e8264174 100644
--- a/arch/arc/Makefile
+++ 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
+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