[PATCH v2] powerpc/boot: Don't always pass -mcpu=powerpc when building 32-bit uImage

[Pali Rohár]

For 32-bit uImage try to use CONFIG_TARGET_CPU option for -mcpu. This fixes
following compiler 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

For 64-bit uImage and 64-bit kernels with 32-bit uImage wrapper there is no
change.

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 at vger.kernel.org
Signed-off-by: Pali Rohár <pali at kernel.org>
---
 arch/powerpc/boot/Makefile | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index a9cd2ea4a861..f56a5f90a5d8 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -44,8 +44,16 @@ else
 BOOTCFLAGS	+= -m64 -mcpu=powerpc64
 endif
 else
+ifdef CONFIG_PPC32
+ifdef CONFIG_TARGET_CPU_BOOL
+BOOTCFLAGS	+= -m32 -mcpu=$(CONFIG_TARGET_CPU)
+else
+BOOTCFLAGS	+= -m32 -mcpu=powerpc
+endif
+else
 BOOTCFLAGS	+= -m32 -mcpu=powerpc
 endif
+endif
 
 BOOTCFLAGS	+= -isystem $(shell $(BOOTCC) -print-file-name=include)
 
-- 
2.20.1