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 <paul.burton@xxxxxxxx>
Fixes: 3702bba5eb4f ("MIPS: Loongson: Add GCC 4.4 support for Loongson2E")
Fixes: 6f7a251a259e ("MIPS: Loongson: Add basic Loongson 2F support")
Fixes: 5188129b8c9f ("MIPS: Loongson-3: Improve -march option and move it to Platform")
Cc: Huacai Chen <chenhc@xxxxxxxxxx>
Cc: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v2.6.32+
---
arch/mips/loongson64/Platform | 4 ++++
arch/mips/vdso/Makefile | 1 +
2 files changed, 5 insertions(+)
diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform
index 28172500f95a..2855daf92fe8 100644
--- 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
index 807f0f782f75..996a934ece7d 100644
--- 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
--
2.23.0
