Re: [PATCH v1 1/5] powerpc/64: Set default CPU in Kconfig

Pali Rohár
2022-12-20T20:14:27Z

On Monday 19 December 2022 19:45:56 Christophe Leroy wrote:
> Since 0069f3d14e7a ("powerpc/64e: Tie PPC_BOOK3E_64 to PPC_E500MC"), the
> only possible BOOK3E/64 are E500, so no need of a default CPU over the
> E5500.
>
> When the user selects book3e, they must have an e500 compatible
> compiler, and it won't work anymore with the default -mcpu=power64, see
> commit d6b551b8f90c ("powerpc/64e: Fix build failure with GCC 12
> (unrecognized opcode: `wrteei')").
>
> For book3s/64, replace GENERIC_CPU by POWERPC64_CPU to match the PPC32
> POWERPC_CPU, and set a default mpcu value in Kconfig directly.
>
> When a user selects a particular CPU, they must ensure the compiler has
> the requested capability. Therefore, remove hidden fallback, instead
> offer user the possibility to say they want to use the toolchain
> default.
>
> It also fixes the non existing E5500_CPU which is a leftover of
> commit d6b551b8f90c ("powerpc/64e: Fix build failure with GCC 12
> (unrecognized opcode: `wrteei')")
>
> Fixes: d6b551b8f90c ("powerpc/64e: Fix build failure with GCC 12 (unrecognized opcode: `wrteei')")
> Reported-by: Pali Rohár <pali@kernel.org>
> Tested-by: Pali Rohár <pali@kernel.org>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

Acked-by: Pali Rohár <pali@kernel.org>

> ---
> arch/powerpc/Makefile | 22 +++++-----------------
> arch/powerpc/platforms/Kconfig.cputype | 12 +++++++-----
> 2 files changed, 12 insertions(+), 22 deletions(-)
>
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index dc4cbf0a5ca9..bf5f0a998273 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -146,19 +146,6 @@ CFLAGS-$(CONFIG_PPC32) += $(call cc-option, $(MULTIPLEWORD))
>
> CFLAGS-$(CONFIG_PPC32) += $(call cc-option,-mno-readonly-in-sdata)
>
> -ifdef CONFIG_PPC_BOOK3S_64
> -ifdef CONFIG_CPU_LITTLE_ENDIAN
> -CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=power8
> -else
> -CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=power4
> -endif
> -CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power10, \
> - $(call cc-option,-mtune=power9, \
> - $(call cc-option,-mtune=power8)))
> -else ifdef CONFIG_PPC_BOOK3E_64
> -CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
> -endif
> -
> ifdef CONFIG_FUNCTION_TRACER
> CC_FLAGS_FTRACE := -pg
> ifdef CONFIG_MPROFILE_KERNEL
> @@ -166,11 +153,12 @@ CC_FLAGS_FTRACE += -mprofile-kernel
> 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))
> +CFLAGS-$(CONFIG_TARGET_CPU_BOOL) += -mcpu=$(CONFIG_TARGET_CPU)
> +AFLAGS-$(CONFIG_TARGET_CPU_BOOL) += -mcpu=$(CONFIG_TARGET_CPU)
>
> -CFLAGS-$(CONFIG_E5500_CPU) += $(call cc-option,-mcpu=e500mc64,-mcpu=powerpc64)
> -CFLAGS-$(CONFIG_E6500_CPU) += $(call cc-option,-mcpu=e6500,$(E5500_CPU))
> +CFLAGS-$(CONFIG_POWERPC64_CPU) += $(call cc-option,-mtune=power10, \
> + $(call cc-option,-mtune=power9, \
> + $(call cc-option,-mtune=power8)))
>
> asinstr := $(call as-instr,lis 9$(comma)foo@high,-DHAVE_AS_ATHIGH=1)
>
> diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
> index 9563336e3348..31cea2eeb59e 100644
> --- a/arch/powerpc/platforms/Kconfig.cputype
> +++ b/arch/powerpc/platforms/Kconfig.cputype
> @@ -118,19 +118,18 @@ endchoice
>
> choice
> prompt "CPU selection"
> - default GENERIC_CPU
> help
> This will create a kernel which is optimised for a particular CPU.
> The resulting kernel may not run on other CPUs, so use this with care.
>
> If unsure, select Generic.
>
> -config GENERIC_CPU
> +config POWERPC64_CPU
> bool "Generic (POWER5 and PowerPC 970 and above)"
> depends on PPC_BOOK3S_64 && !CPU_LITTLE_ENDIAN
> select PPC_64S_HASH_MMU
>
> -config GENERIC_CPU
> +config POWERPC64_CPU
> bool "Generic (POWER8 and above)"
> depends on PPC_BOOK3S_64 && CPU_LITTLE_ENDIAN
> select ARCH_HAS_FAST_MULTIPLIER
> @@ -233,13 +232,12 @@ config E500MC_CPU
>
> 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 && !TOOLCHAIN_DEFAULT_CPU
> + default !TOOLCHAIN_DEFAULT_CPU
>
> config TARGET_CPU
> string
> @@ -251,6 +249,10 @@ config TARGET_CPU
> default "power8" if POWER8_CPU
> default "power9" if POWER9_CPU
> default "power10" if POWER10_CPU
> + default "e500mc64" if E5500_CPU
> + default "e6500" if E6500_CPU
> + default "power4" if POWERPC64_CPU && !CPU_LITTLE_ENDIAN
> + default "power8" if POWERPC64_CPU && CPU_LITTLE_ENDIAN
> default "405" if 405_CPU
> default "440" if 440_CPU
> default "464" if 464_CPU
> --
> 2.38.1
>