MIPS: Disable Loongson MMI instructions for kernel build

GCC 9.x automatically enables support for Loongson MMI instructions when using some -march= flags, and then errors out when -msoft-float is specified with: cc1: error: ‘-mloongson-mmi’ must be used with ‘-mhard-float’ The kernel shouldn't be using these MMI instructions anyway, just as it doesn't use floating point instructions. Explicitly disable them in order to fix the build with GCC 9.x. Signed-off-by: Paul Burton <[email protected]> Fixes: 3702bba ("MIPS: Loongson: Add GCC 4.4 support for Loongson2E") Fixes: 6f7a251 ("MIPS: Loongson: Add basic Loongson 2F support") Fixes: 5188129 ("MIPS: Loongson-3: Improve -march option and move it to Platform") Cc: Huacai Chen <[email protected]> Cc: Jiaxun Yang <[email protected]> Cc: [email protected] # v2.6.32+ Cc: [email protected]
kmaincent · Oct 10, 2019 · 2f2b4fd · 2f2b4fd
1 parent 38dffe1
commit 2f2b4fd
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diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform
@@ -66,6 +66,10 @@ else
       $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64)
 endif
 
+# Some -march= flags enable MMI instructions, and GCC complains about that
+# support being enabled alongside -msoft-float. Thus explicitly disable MMI.
+cflags-y += $(call cc-option,-mno-loongson-mmi)
+
 #
 # Loongson Machines' Support
 #

diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
@@ -15,6 +15,7 @@ ccflags-vdso := \
 	$(filter -mmicromips,$(KBUILD_CFLAGS)) \
 	$(filter -march=%,$(KBUILD_CFLAGS)) \
 	$(filter -m%-float,$(KBUILD_CFLAGS)) \
+	$(filter -mno-loongson-%,$(KBUILD_CFLAGS)) \
 	-D__VDSO__
 
 ifdef CONFIG_CC_IS_CLANG