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MIPS: Loongson-3: Improve -march option and move it to Platform

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If GCC >= 4.9 and Binutils >=2.25, we use -march=loongson3a, otherwise
we use -march=mips64r2, this can slightly improve performance. Besides,
arch/mips/loongson64/Platform is a better location rather than arch/
mips/Makefile.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12161/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Huacai Chen 2016-01-21 21:09:48 +08:00 committed by Ralf Baechle
parent 6e52684467
commit 5188129b8c
2 changed files with 21 additions and 10 deletions
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10
arch/mips/Makefile
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@ -166,16 +166,6 @@ cflags-$(CONFIG_CPU_CAVIUM_OCTEON) += -Wa,-march=octeon
endif
cflags-$(CONFIG_CAVIUM_CN63XXP1) += -Wa,-mfix-cn63xxp1
cflags-$(CONFIG_CPU_BMIPS) += -march=mips32 -Wa,-mips32 -Wa,--trap
#
# binutils from v2.25 on and gcc starting from v4.9.0 treat -march=loongson3a
# as MIPS64 R1; older versions as just R1. This leaves the possibility open
# that GCC might generate R2 code for -march=loongson3a which then is rejected
# by GAS. The cc-option can't probe for this behaviour so -march=loongson3a
# can't easily be used safely within the kbuild framework.
#
cflags-$(CONFIG_CPU_LOONGSON3) += \
$(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) \
-Wa,-mips64r2 -Wa,--trap
cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,)
cflags-$(CONFIG_CPU_R4400_WORKAROUNDS) += $(call cc-option,-mfix-r4400,)

21
arch/mips/loongson64/Platform
View File

@ -22,6 +22,27 @@ ifdef CONFIG_CPU_LOONGSON2F_WORKAROUNDS
endif
endif
cflags-$(CONFIG_CPU_LOONGSON3) += -Wa,--trap
#
# binutils from v2.25 on and gcc starting from v4.9.0 treat -march=loongson3a
# as MIPS64 R2; older versions as just R1. This leaves the possibility open
# that GCC might generate R2 code for -march=loongson3a which then is rejected
# by GAS. The cc-option can't probe for this behaviour so -march=loongson3a
# can't easily be used safely within the kbuild framework.
#
ifeq ($(call cc-ifversion, -ge, 0409, y), y)
ifeq ($(call ld-ifversion, -ge, 22500000, y), y)
cflags-$(CONFIG_CPU_LOONGSON3) += \
$(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64)
else
cflags-$(CONFIG_CPU_LOONGSON3) += \
$(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64)
endif
else
cflags-$(CONFIG_CPU_LOONGSON3) += \
$(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64)
endif
#
# Loongson Machines' Support
#