Use -march and -mabi instead of -m32/-mno-float

arch/riscv/Makefile

@@ -32,31 +32,32 @@ ifeq ($(CONFIG_64BIT),y)
 	BITS := 64
 	UTS_MACHINE := riscv64
 
-	KBUILD_CFLAGS += -m64
-	KBUILD_AFLAGS += -m64
+	KBUILD_CFLAGS += -mabi=lp64
+	KBUILD_AFLAGS += -mabi=lp64
+	KBUILD_MARCH = rv64im
 	LDFLAGS += -melf64lriscv
 else
 	BITS := 32
 	UTS_MACHINE := riscv32
 
-	KBUILD_CFLAGS += -m32
-	KBUILD_AFLAGS += -m32
+	KBUILD_CFLAGS += -mabi=ilp32
+	KBUILD_AFLAGS += -mabi=ilp32
+	KBUILD_MARCH = rv32im
 	LDFLAGS += -melf32lriscv
 endif
 
-ifeq ($(CONFIG_RV_ATOMIC),)
-KBUILD_CFLAGS += -mno-atomic
+ifeq ($(CONFIG_RV_ATOMIC),y)
+	KBUILD_RV_ATOMIC = a
 endif
 
 KBUILD_CFLAGS += -Wall
-KBUILD_CFLAGS += -mno-float
-KBUILD_AFLAGS += -mno-float
 
 ifeq ($(CONFIG_RVC),y)
-	KBUILD_CFLAGS += -mrvc
-	KBUILD_AFLAGS += -Wa,-mrvc
+	KBUILD_RVC = c
 endif
 
+KBUILD_AFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_RV_ATOMIC)fd$(KBUILD_RVC)
+
 KBUILD_CFLAGS += -mno-save-restore
 
 head-y := arch/riscv/kernel/head.o