On Sunday 28 August 2022 17:39:25 Christophe Leroy wrote:

Le 28/08/2022 à 19:33, Christophe Leroy a écrit :

quoted

Le 28/08/2022 à 11:56, Pali Rohár a écrit :

quoted

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

corenet64_smp_defconfig :

   BOOTAS  arch/powerpc/boot/crt0.o
powerpc64-linux-gcc: error: missing argument to '-mcpu='
make[1]: *** [arch/powerpc/boot/Makefile:237 : arch/powerpc/boot/crt0.o] 
Erreur 1
make: *** [arch/powerpc/Makefile:253 : uImage] Erreur 2

Seems like in fact, E5500_CPU and E6500_CPU are not taken into account 
in CONFIG_TARGET_CPU, and get special treatment directly in 
arch/powerpc/Makefile.

This goes unnoticed because of CFLAGS-$(CONFIG_TARGET_CPU_BOOL) += 
$(call cc-option,-mcpu=$(CONFIG_TARGET_CPU))

I think we need to fix that prior to your patch.

It looks like that CONFIG_TARGET_CPU is broken.

  $ make ARCH=powerpc corenet64_smp_defconfig CROSS_COMPILE=powerpc64-linux-gnu-
  ...
  # configuration written to .config

  $ grep CONFIG_TARGET_CPU .config
  CONFIG_TARGET_CPU_BOOL=y

CONFIG_TARGET_CPU_BOOL is set but CONFIG_TARGET_CPU not!

quoted

Christophe

quoted

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)