[PATCH v3] powerpc/boot: Don't always pass -mcpu=powerpc when building 32-bit uImage

["Pali Rohár" <pali@kernel.org>]

When CONFIG_TARGET_CPU is specified then pass its value to the compiler
-mcpu option. This fixes following build error when building kernel with
powerpc e500 SPE capable cross compilers:

    BOOTAS  arch/powerpc/boot/crt0.o
  powerpc-linux-gnuspe-gcc: error: unrecognized argument in option ‘-mcpu=powerpc’
  powerpc-linux-gnuspe-gcc: note: valid arguments to ‘-mcpu=’ are: 8540 8548 native
  make[1]: *** [arch/powerpc/boot/Makefile:231: arch/powerpc/boot/crt0.o] Error 1

Similar change was already introduced for the main powerpc Makefile in
commit 446cda1b21d9 ("powerpc/32: Don't always pass -mcpu=powerpc to the
compiler").

Fixes: 40a75584e526 ("powerpc/boot: Build wrapper for an appropriate CPU")
Cc: stable@vger.kernel.org # 446cda1b21d9 ("powerpc/32: Don't always pass -mcpu=powerpc to the compiler")
Signed-off-by: Pali Rohár <pali@kernel.org>
---
 arch/powerpc/boot/Makefile | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index a9cd2ea4a861..1957a3de7a1c 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -38,13 +38,19 @@ BOOTCFLAGS    := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
 		 $(LINUXINCLUDE)
 
 ifdef CONFIG_PPC64_BOOT_WRAPPER
-ifdef CONFIG_CPU_LITTLE_ENDIAN
-BOOTCFLAGS	+= -m64 -mcpu=powerpc64le
+BOOTCFLAGS	+= -m64
 else
-BOOTCFLAGS	+= -m64 -mcpu=powerpc64
+BOOTCFLAGS	+= -m32
 endif
+
+ifdef CONFIG_TARGET_CPU_BOOL
+BOOTCFLAGS	+= -mcpu=$(CONFIG_TARGET_CPU)
+else ifdef CONFIG_PPC64_BOOT_WRAPPER
+ifdef CONFIG_CPU_LITTLE_ENDIAN
+BOOTCFLAGS	+= -mcpu=powerpc64le
 else
-BOOTCFLAGS	+= -m32 -mcpu=powerpc
+BOOTCFLAGS	+= -mcpu=powerpc64
+endif
 endif
 
 BOOTCFLAGS	+= -isystem $(shell $(BOOTCC) -print-file-name=include)
-- 
2.20.1