Kernel builds set their own default -mcpu for a given ISA build.
But that gets in the way of "custom" -mcpu flags from propagating
into kernel build.
This will also be used in next patches for HSDK-4xD board support which
uses a different -mcpu to effect dual issue scheduling.
Signed-off-by: Eugeniy Paltsev <eugeniy.palt...@synopsys.com>
---
arch/arc/Kconfig | 9 +++++++++
arch/arc/Makefile | 21 +++++++++++++++++++--
2 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index ff306246d0f8..7034c217708f 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -377,6 +377,15 @@ config ARC_HAS_SWAPE
bool "Insn: SWAPE (endian-swap)"
default y
+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.
+
if ISA_ARCV2
config ARC_USE_UNALIGNED_MEM_ACCESS
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
--
2.21.3
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