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ARM: 7777/1: Avoid extra calls to the C compiler 

Starting up the C compiler can be a slow operation on some systems.
Though these calls don't individually take a lot of time, they add up.
Rearrange the ARM Makefile a bit to avoid extra calls to the compiler
when they can be easily avoided.

When running with the Chrome OS ARM cross compiler
"armv7a-cros-linux-gnueabi-", this shaved .55 seconds (from 5.31
seconds to 4.76 seconds) off an incremental build of the kernel:
  time make -j32 ARCH=arm CROSS_COMPILE=armv7a-cros-linux-gnueabi-

Thanks to Mike Frysinger for the clean trick to make this work.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
hifive-unleashed-5.1
Douglas Anderson 2013-06-27 04:32:06 +01:00 committed by Russell King
parent 81793bab5d
commit 1b21376a73
1 changed files with 31 additions and 25 deletions
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56
arch/arm/Makefile
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@ -59,37 +59,43 @@ comma = ,
# Note that GCC does not numerically define an architecture version
# macro, but instead defines a whole series of macros which makes
# testing for a specific architecture or later rather impossible.
arch-$(CONFIG_CPU_32v7) :=-D__LINUX_ARM_ARCH__=7 $(call cc-option,-march=armv7-a,-march=armv5t -Wa$(comma)-march=armv7-a)
arch-$(CONFIG_CPU_32v6) :=-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6,-march=armv5t -Wa$(comma)-march=armv6)
arch-$(CONFIG_CPU_32v7) =-D__LINUX_ARM_ARCH__=7 $(call cc-option,-march=armv7-a,-march=armv5t -Wa$(comma)-march=armv7-a)
arch-$(CONFIG_CPU_32v6) =-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6,-march=armv5t -Wa$(comma)-march=armv6)
# Only override the compiler option if ARMv6. The ARMv6K extensions are
# always available in ARMv7
ifeq ($(CONFIG_CPU_32v6),y)
arch-$(CONFIG_CPU_32v6K) :=-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6k,-march=armv5t -Wa$(comma)-march=armv6k)
arch-$(CONFIG_CPU_32v6K) =-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6k,-march=armv5t -Wa$(comma)-march=armv6k)
endif
arch-$(CONFIG_CPU_32v5) :=-D__LINUX_ARM_ARCH__=5 $(call cc-option,-march=armv5te,-march=armv4t)
arch-$(CONFIG_CPU_32v4T) :=-D__LINUX_ARM_ARCH__=4 -march=armv4t
arch-$(CONFIG_CPU_32v4) :=-D__LINUX_ARM_ARCH__=4 -march=armv4
arch-$(CONFIG_CPU_32v3) :=-D__LINUX_ARM_ARCH__=3 -march=armv3
arch-$(CONFIG_CPU_32v5) =-D__LINUX_ARM_ARCH__=5 $(call cc-option,-march=armv5te,-march=armv4t)
arch-$(CONFIG_CPU_32v4T) =-D__LINUX_ARM_ARCH__=4 -march=armv4t
arch-$(CONFIG_CPU_32v4) =-D__LINUX_ARM_ARCH__=4 -march=armv4
arch-$(CONFIG_CPU_32v3) =-D__LINUX_ARM_ARCH__=3 -march=armv3
# Evaluate arch cc-option calls now
arch-y := $(arch-y)
# This selects how we optimise for the processor.
tune-$(CONFIG_CPU_ARM7TDMI) :=-mtune=arm7tdmi
tune-$(CONFIG_CPU_ARM720T) :=-mtune=arm7tdmi
tune-$(CONFIG_CPU_ARM740T) :=-mtune=arm7tdmi
tune-$(CONFIG_CPU_ARM9TDMI) :=-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM940T) :=-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM946E) :=$(call cc-option,-mtune=arm9e,-mtune=arm9tdmi)
tune-$(CONFIG_CPU_ARM920T) :=-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM922T) :=-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM925T) :=-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM926T) :=-mtune=arm9tdmi
tune-$(CONFIG_CPU_FA526) :=-mtune=arm9tdmi
tune-$(CONFIG_CPU_SA110) :=-mtune=strongarm110
tune-$(CONFIG_CPU_SA1100) :=-mtune=strongarm1100
tune-$(CONFIG_CPU_XSCALE) :=$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
tune-$(CONFIG_CPU_XSC3) :=$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
tune-$(CONFIG_CPU_FEROCEON) :=$(call cc-option,-mtune=marvell-f,-mtune=xscale)
tune-$(CONFIG_CPU_V6) :=$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
tune-$(CONFIG_CPU_V6K) :=$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
tune-$(CONFIG_CPU_ARM7TDMI) =-mtune=arm7tdmi
tune-$(CONFIG_CPU_ARM720T) =-mtune=arm7tdmi
tune-$(CONFIG_CPU_ARM740T) =-mtune=arm7tdmi
tune-$(CONFIG_CPU_ARM9TDMI) =-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM940T) =-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM946E) =$(call cc-option,-mtune=arm9e,-mtune=arm9tdmi)
tune-$(CONFIG_CPU_ARM920T) =-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM922T) =-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM925T) =-mtune=arm9tdmi
tune-$(CONFIG_CPU_ARM926T) =-mtune=arm9tdmi
tune-$(CONFIG_CPU_FA526) =-mtune=arm9tdmi
tune-$(CONFIG_CPU_SA110) =-mtune=strongarm110
tune-$(CONFIG_CPU_SA1100) =-mtune=strongarm1100
tune-$(CONFIG_CPU_XSCALE) =$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
tune-$(CONFIG_CPU_XSC3) =$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
tune-$(CONFIG_CPU_FEROCEON) =$(call cc-option,-mtune=marvell-f,-mtune=xscale)
tune-$(CONFIG_CPU_V6) =$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
tune-$(CONFIG_CPU_V6K) =$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
# Evaluate tune cc-option calls now
tune-y := $(tune-y)
ifeq ($(CONFIG_AEABI),y)
CFLAGS_ABI :=-mabi=aapcs-linux -mno-thumb-interwork