MIPS: Makefile: Pass -march option on Loongson3A cores (a8140f36) · Commits · 戴 / test

The loongson 3A cores do not select a suitable -march option so the build system uses the default one from the toolchain. This may or may not be suitable for a loongson 3A build. In order to avoid that, we explicitly set a suitable -march option for that core. Furthermore, some very old compilers don't support -march= at all and there is the possibility of toolchain combinations such as GCC 4.9 and binutils 2.24 for which -march=loongson3a will result in MIPS64 R2 code being generated but then rejected by GAS. So treat the Longsoon 3A as an R2 CPU. Signed-off-by:

Ralf Baechle <ralf@linux-mips.org>

arch/mips/Makefile

+10 −0

Original line number	Diff line number	Diff line
		@@ -182,6 +182,16 @@ 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,)

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