[PATCH 5.8 89/99] MIPS: Loongson2ef: Disable Loongson MMI instructions

[Greg Kroah-Hartman]

From: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>

commit b13812ddea615b6507beef24f76540c0c1143c5c upstream.

It was missed when I was forking Loongson2ef from Loongson64 but
should be applied to Loongson2ef as march=loongson2f
will also enable Loongson MMI in GCC-9+.

Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Fixes: 71e2f4dd5a65 ("MIPS: Fork loongson2ef from loongson64")
Reported-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v5.8+
Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/mips/loongson2ef/Platform |    4 ++++
 1 file changed, 4 insertions(+)

--- a/arch/mips/loongson2ef/Platform
+++ b/arch/mips/loongson2ef/Platform
@@ -22,6 +22,10 @@ ifdef CONFIG_CPU_LOONGSON2F_WORKAROUNDS
   endif
 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
 #