powerpc: Add CONFIG_PPC64_ELF_ABI_V1 and CONFIG_PPC64_ELF_ABI_V2

At the time being, we use CONFIG_CPU_LITTLE_ENDIAN and
CONFIG_CPU_BIG_ENDIAN to pass -mabi=elfv1 or elfv2 to
compiler, then define a PPC64_ELF_ABI_v1 or PPC64_ELF_ABI_v2
macro in asm/types.h based on _CALL_ELF define set by the compiler.

Make it more straight forward with a CONFIG option that
is directly usable.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1eca1addbc550167da9841c7340a010d0c4b2200.1652074503.git.christophe.leroy@csgroup.eu

arch/powerpc/Makefile

@@ -89,10 +89,10 @@ endif
 
 ifdef CONFIG_PPC64
 ifndef CONFIG_CC_IS_CLANG
-cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mabi=elfv1)
-cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mcall-aixdesc)
-aflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mabi=elfv1)
-aflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mabi=elfv2
+cflags-$(CONFIG_PPC64_ELF_ABI_V1)	+= $(call cc-option,-mabi=elfv1)
+cflags-$(CONFIG_PPC64_ELF_ABI_V1)	+= $(call cc-option,-mcall-aixdesc)
+aflags-$(CONFIG_PPC64_ELF_ABI_V1)	+= $(call cc-option,-mabi=elfv1)
+aflags-$(CONFIG_PPC64_ELF_ABI_V2)	+= -mabi=elfv2
 endif
 endif
 
@@ -141,7 +141,7 @@ endif
 
 CFLAGS-$(CONFIG_PPC64)	:= $(call cc-option,-mtraceback=no)
 ifndef CONFIG_CC_IS_CLANG
-ifdef CONFIG_CPU_LITTLE_ENDIAN
+ifdef CONFIG_PPC64_ELF_ABI_V2
 CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mabi=elfv2,$(call cc-option,-mcall-aixdesc))
 AFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mabi=elfv2)
 else

arch/powerpc/boot/Makefile

@@ -53,6 +53,8 @@ ifdef CONFIG_CPU_BIG_ENDIAN
 BOOTCFLAGS	+= -mbig-endian
 else
 BOOTCFLAGS	+= -mlittle-endian
+endif
+ifdef CONFIG_PPC64_ELF_ABI_V2
 BOOTCFLAGS	+= $(call cc-option,-mabi=elfv2)
 endif
 

arch/powerpc/platforms/Kconfig.cputype

@@ -552,6 +552,12 @@ config CPU_LITTLE_ENDIAN
 
 endchoice
 
+config PPC64_ELF_ABI_V1
+	def_bool PPC64 && CPU_BIG_ENDIAN
+
+config PPC64_ELF_ABI_V2
+	def_bool PPC64 && CPU_LITTLE_ENDIAN
+
 config PPC64_BOOT_WRAPPER
 	def_bool n
 	depends on CPU_LITTLE_ENDIAN