From: Christophe Leroy christophe.leroy@csgroup.eu
[ Upstream commit 446cda1b21d9a6b3697fe399c6a3a00ff4a285f5 ]
Since commit 4bf4f42a2feb ("powerpc/kbuild: Set default generic machine type for 32-bit compile"), when building a 32 bits kernel with a bi-arch version of GCC, or when building a book3s/32 kernel, the option -mcpu=powerpc is passed to GCC at all time, relying on it being eventually overriden by a subsequent -mcpu=xxxx.
But when building the same kernel with a 32 bits only version of GCC, that is not done, relying on gcc being built with the expected default CPU.
This logic has two problems. First, it is a bit fragile to rely on whether the GCC version is bi-arch or not, because today we can have bi-arch versions of GCC configured with a 32 bits default. Second, there are some versions of GCC which don't support -mcpu=powerpc, for instance for e500 SPE-only versions.
So, stop relying on this approximative logic and allow the user to decide whether he/she wants to use the toolchain's default CPU or if he/she wants to set one, and allow only possible CPUs based on the selected target.
Reported-by: Pali Rohár pali@kernel.org Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu Tested-by: Pali Rohár pali@kernel.org Reviewed-by: Arnd Bergmann arnd@arndb.de Reviewed-by: Segher Boessenkool segher@kernel.crashing.org Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/d4df724691351531bf46d685d654689e5dfa0d74.165754915... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/Makefile | 26 +------------------------- arch/powerpc/platforms/Kconfig.cputype | 21 ++++++++++++++++++--- 2 files changed, 19 insertions(+), 28 deletions(-)
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index b9d2fcf030d0..eedd114a017c 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -17,23 +17,6 @@ HAS_BIARCH := $(call cc-option-yn, -m32) # Set default 32 bits cross compilers for vdso and boot wrapper CROSS32_COMPILE ?=
-ifeq ($(HAS_BIARCH),y) -ifeq ($(CROSS32_COMPILE),) -ifdef CONFIG_PPC32 -# These options will be overridden by any -mcpu option that the CPU -# or platform code sets later on the command line, but they are needed -# to set a sane 32-bit cpu target for the 64-bit cross compiler which -# may default to the wrong ISA. -KBUILD_CFLAGS += -mcpu=powerpc -KBUILD_AFLAGS += -mcpu=powerpc -endif -endif -endif - -ifdef CONFIG_PPC_BOOK3S_32 -KBUILD_CFLAGS += -mcpu=powerpc -endif - # If we're on a ppc/ppc64/ppc64le machine use that defconfig, otherwise just use # ppc64_defconfig because we have nothing better to go on. uname := $(shell uname -m) @@ -192,6 +175,7 @@ endif endif
CFLAGS-$(CONFIG_TARGET_CPU_BOOL) += $(call cc-option,-mcpu=$(CONFIG_TARGET_CPU)) +AFLAGS-$(CONFIG_TARGET_CPU_BOOL) += $(call cc-option,-mcpu=$(CONFIG_TARGET_CPU))
# Altivec option not allowed with e500mc64 in GCC. ifdef CONFIG_ALTIVEC @@ -202,14 +186,6 @@ endif CFLAGS-$(CONFIG_E5500_CPU) += $(E5500_CPU) CFLAGS-$(CONFIG_E6500_CPU) += $(call cc-option,-mcpu=e6500,$(E5500_CPU))
-ifdef CONFIG_PPC32 -ifdef CONFIG_PPC_E500MC -CFLAGS-y += $(call cc-option,-mcpu=e500mc,-mcpu=powerpc) -else -CFLAGS-$(CONFIG_E500) += $(call cc-option,-mcpu=8540 -msoft-float,-mcpu=powerpc) -endif -endif - asinstr := $(call as-instr,lis 9$(comma)foo@high,-DHAVE_AS_ATHIGH=1)
KBUILD_CPPFLAGS += -I $(srctree)/arch/$(ARCH) $(asinstr) diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index f0330ce498d1..cfac99a63505 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -118,9 +118,9 @@ config GENERIC_CPU depends on PPC64 && CPU_LITTLE_ENDIAN select ARCH_HAS_FAST_MULTIPLIER
-config GENERIC_CPU +config POWERPC_CPU bool "Generic 32 bits powerpc" - depends on PPC32 && !PPC_8xx + depends on PPC32 && !PPC_8xx && !PPC_85xx
config CELL_CPU bool "Cell Broadband Engine" @@ -174,11 +174,23 @@ config G4_CPU depends on PPC_BOOK3S_32 select ALTIVEC
+config E500_CPU + bool "e500 (8540)" + depends on PPC_85xx && !PPC_E500MC + +config E500MC_CPU + bool "e500mc" + depends on PPC_85xx && PPC_E500MC + +config TOOLCHAIN_DEFAULT_CPU + bool "Rely on the toolchain's implicit default CPU" + depends on PPC32 + endchoice
config TARGET_CPU_BOOL bool - default !GENERIC_CPU + default !GENERIC_CPU && !TOOLCHAIN_DEFAULT_CPU
config TARGET_CPU string @@ -193,6 +205,9 @@ config TARGET_CPU default "e300c2" if E300C2_CPU default "e300c3" if E300C3_CPU default "G4" if G4_CPU + default "8540" if E500_CPU + default "e500mc" if E500MC_CPU + default "powerpc" if POWERPC_CPU
config PPC_BOOK3S def_bool y