Re: [PATCH v2 1/6] ARM: remove support for highmem on VIVT

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Low] ARM: configs: mv78xx0_defconfig retains unreachable
  CONFIG_HIGHMEM=y
--

commit a6e3d614ee0118d4a0f2639acca9b5620bed4dd2
Author: Arnd Bergmann <arnd@arndb.de>

ARM: remove support for highmem on VIVT

This commit makes CONFIG_HIGHMEM depend on !CPU_CACHE_VIVT, drops the
now-unreachable CONFIG_HIGHMEM=y entries from VIVT defconfigs, and
removes VIVT highmem handling from ARM cache and DMA code.

Link: https://lore.kernel.org/all/20251219171412.GG254720@nvidia.com/

> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index ffbc7f3861315..77614080f317c 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1210,6 +1210,7 @@ config ARCH_SPARSEMEM_ENABLE
>  config HIGHMEM
>  	bool "High Memory Support"
>  	depends on MMU
> +	depends on !CPU_CACHE_VIVT
>  	select KMAP_LOCAL
>  	select KMAP_LOCAL_NON_LINEAR_PTE_ARRAY
>  	help
> diff --git a/arch/arm/configs/gemini_defconfig b/arch/arm/configs/gemini_defconfig
> index 5860b2fe7d1fb..95debf46581be 100644
> --- a/arch/arm/configs/gemini_defconfig
> +++ b/arch/arm/configs/gemini_defconfig
> @@ -11,7 +11,6 @@ CONFIG_KEXEC=y
>  CONFIG_ARCH_MULTI_V4=y
>  # CONFIG_ARCH_MULTI_V7 is not set
>  CONFIG_ARCH_GEMINI=y
> -CONFIG_HIGHMEM=y
>  CONFIG_CMDLINE="console=ttyS0,115200n8"
>  CONFIG_PM=y
>  CONFIG_PARTITION_ADVANCED=y
> diff --git a/arch/arm/configs/multi_v5_defconfig b/arch/arm/configs/multi_v5_defconfig
> index a0d2fb2fcf9a8..bc34b6026e377 100644
> --- a/arch/arm/configs/multi_v5_defconfig
> +++ b/arch/arm/configs/multi_v5_defconfig
> @@ -27,7 +27,6 @@ CONFIG_MACH_D2NET_DT=y
>  CONFIG_MACH_MSS2_DT=y
>  CONFIG_ARCH_SUNXI=y
>  CONFIG_ARCH_VERSATILE=y
> -CONFIG_HIGHMEM=y
>  CONFIG_ARM_APPENDED_DTB=y
>  CONFIG_ARM_ATAG_DTB_COMPAT=y
>  CONFIG_CPU_FREQ=y
> diff --git a/arch/arm/configs/mvebu_v5_defconfig b/arch/arm/configs/mvebu_v5_defconfig
> index dbc6c511e70bc..5adf6c75304eb 100644
> --- a/arch/arm/configs/mvebu_v5_defconfig
> +++ b/arch/arm/configs/mvebu_v5_defconfig
> @@ -13,7 +13,6 @@ CONFIG_MACH_RD88F5182_DT=y
>  CONFIG_MACH_LINKSTATION_MINI=y
>  CONFIG_MACH_D2NET_DT=y
>  CONFIG_MACH_MSS2_DT=y
> -CONFIG_HIGHMEM=y
>  CONFIG_ARM_APPENDED_DTB=y
>  CONFIG_ARM_ATAG_DTB_COMPAT=y
>  CONFIG_CPU_FREQ=y

[Severity: Low]
Should arch/arm/configs/mv78xx0_defconfig also drop CONFIG_HIGHMEM=y?
ARCH_MV78XX0 selects CPU_FEROCEON, which selects CPU_CACHE_VIVT, leaving
CONFIG_HIGHMEM=y unreachable there as well.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261112112528.1116405-1-arnd@kernel.org?part=1