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authorRalf Baechle <ralf@linux-mips.org>2015-02-19 13:47:20 +0100
committerRalf Baechle <ralf@linux-mips.org>2015-02-19 13:47:20 +0100
commita8140f36af2a8b63fd507bd8c1fa00df7819e0de (patch)
tree4fb445ab51030bae2fefb4529538e2899fa03146 /arch/mips/Makefile
parented4cbc81addbc076b016c5b979fd1a02f0897f0a (diff)
MIPS: Makefile: Pass -march option on Loongson3A cores
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>
Diffstat (limited to 'arch/mips/Makefile')
-rw-r--r--arch/mips/Makefile10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 2563a088d3b8..4547719e4e61 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -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,)