xref: /kernel/linux/linux-6.6/arch/sh/mm/Kconfig

# SPDX-License-Identifier: GPL-2.0
menu "Memory management options"

config MMU
        bool "Support for memory management hardware"
	depends on !CPU_SH2
	default y
	help
	  Some SH processors (such as SH-2/SH-2A) lack an MMU. In order to
	  boot on these systems, this option must not be set.

	  On other systems (such as the SH-3 and 4) where an MMU exists,
	  turning this off will boot the kernel on these machines with the
	  MMU implicitly switched off.

config PAGE_OFFSET
	hex
	default "0x80000000" if MMU
	default "0x00000000"

config ARCH_FORCE_MAX_ORDER
	int "Order of maximal physically contiguous allocations"
	default "8" if PAGE_SIZE_16KB
	default "6" if PAGE_SIZE_64KB
	default "13" if !MMU
	default "10"
	help
	  The kernel page allocator limits the size of maximal physically
	  contiguous allocations. The limit is called MAX_ORDER and it
	  defines the maximal power of two of number of pages that can be
	  allocated as a single contiguous block. This option allows
	  overriding the default setting when ability to allocate very
	  large blocks of physically contiguous memory is required.

	  The page size is not necessarily 4KB. Keep this in mind when
	  choosing a value for this option.

	  Don't change if unsure.

config MEMORY_START
	hex "Physical memory start address"
	default "0x08000000"
	help
	  Computers built with Hitachi SuperH processors always
	  map the ROM starting at address zero.  But the processor
	  does not specify the range that RAM takes.

	  The physical memory (RAM) start address will be automatically
	  set to 08000000. Other platforms, such as the Solution Engine
	  boards typically map RAM at 0C000000.

	  Tweak this only when porting to a new machine which does not
	  already have a defconfig. Changing it from the known correct
	  value on any of the known systems will only lead to disaster.

config MEMORY_SIZE
	hex "Physical memory size"
	default "0x04000000"
	help
	  This sets the default memory size assumed by your SH kernel. It can
	  be overridden as normal by the 'mem=' argument on the kernel command
	  line. If unsure, consult your board specifications or just leave it
	  as 0x04000000 which was the default value before this became
	  configurable.

# Physical addressing modes

config 29BIT
	def_bool !32BIT
	select UNCACHED_MAPPING

config 32BIT
	bool
	default !MMU

config PMB
	bool "Support 32-bit physical addressing through PMB"
	depends on MMU && CPU_SH4A && !CPU_SH4AL_DSP
	select 32BIT
	select UNCACHED_MAPPING
	help
	  If you say Y here, physical addressing will be extended to
	  32-bits through the SH-4A PMB. If this is not set, legacy
	  29-bit physical addressing will be used.

config X2TLB
	def_bool y
	depends on (CPU_SHX2 || CPU_SHX3) && MMU

config VSYSCALL
	bool "Support vsyscall page"
	depends on MMU && (CPU_SH3 || CPU_SH4)
	default y
	help
	  This will enable support for the kernel mapping a vDSO page
	  in process space, and subsequently handing down the entry point
	  to the libc through the ELF auxiliary vector.

	  From the kernel side this is used for the signal trampoline.
	  For systems with an MMU that can afford to give up a page,
	  (the default value) say Y.

config NUMA
	bool "Non-Uniform Memory Access (NUMA) Support"
	depends on MMU && SYS_SUPPORTS_NUMA
	select ARCH_WANT_NUMA_VARIABLE_LOCALITY
	default n
	help
	  Some SH systems have many various memories scattered around
	  the address space, each with varying latencies. This enables
	  support for these blocks by binding them to nodes and allowing
	  memory policies to be used for prioritizing and controlling
	  allocation behaviour.

config NODES_SHIFT
	int
	default "3" if CPU_SUBTYPE_SHX3
	default "1"
	depends on NUMA

config ARCH_FLATMEM_ENABLE
	def_bool y
	depends on !NUMA

config ARCH_SPARSEMEM_ENABLE
	def_bool y
	select SPARSEMEM_STATIC

config ARCH_SPARSEMEM_DEFAULT
	def_bool y

config ARCH_SELECT_MEMORY_MODEL
	def_bool y

config ARCH_MEMORY_PROBE
	def_bool y
	depends on MEMORY_HOTPLUG

config IOREMAP_FIXED
       def_bool y
       depends on X2TLB

config UNCACHED_MAPPING
	bool

config HAVE_SRAM_POOL
	bool
	select GENERIC_ALLOCATOR

choice
	prompt "Kernel page size"
	default PAGE_SIZE_4KB

config PAGE_SIZE_4KB
	bool "4kB"
	help
	  This is the default page size used by all SuperH CPUs.

config PAGE_SIZE_8KB
	bool "8kB"
	depends on !MMU || X2TLB
	help
	  This enables 8kB pages as supported by SH-X2 and later MMUs.

config PAGE_SIZE_16KB
	bool "16kB"
	depends on !MMU
	help
	  This enables 16kB pages on MMU-less SH systems.

config PAGE_SIZE_64KB
	bool "64kB"
	depends on !MMU || CPU_SH4
	help
	  This enables support for 64kB pages, possible on all SH-4
	  CPUs and later.

endchoice

choice
	prompt "HugeTLB page size"
	depends on HUGETLB_PAGE
	default HUGETLB_PAGE_SIZE_1MB if PAGE_SIZE_64KB
	default HUGETLB_PAGE_SIZE_64K

config HUGETLB_PAGE_SIZE_64K
	bool "64kB"
	depends on !PAGE_SIZE_64KB

config HUGETLB_PAGE_SIZE_256K
	bool "256kB"
	depends on X2TLB

config HUGETLB_PAGE_SIZE_1MB
	bool "1MB"

config HUGETLB_PAGE_SIZE_4MB
	bool "4MB"
	depends on X2TLB

config HUGETLB_PAGE_SIZE_64MB
	bool "64MB"
	depends on X2TLB

endchoice

config SCHED_MC
	bool "Multi-core scheduler support"
	depends on SMP
	default y
	help
	  Multi-core scheduler support improves the CPU scheduler's decision
	  making when dealing with multi-core CPU chips at a cost of slightly
	  increased overhead in some places. If unsure say N here.

endmenu

menu "Cache configuration"

config SH7705_CACHE_32KB
	bool "Enable 32KB cache size for SH7705"
	depends on CPU_SUBTYPE_SH7705
	default y

choice
	prompt "Cache mode"
	default CACHE_WRITEBACK if CPU_SH2A || CPU_SH3 || CPU_SH4
	default CACHE_WRITETHROUGH if (CPU_SH2 && !CPU_SH2A)

config CACHE_WRITEBACK
	bool "Write-back"

config CACHE_WRITETHROUGH
	bool "Write-through"
	help
	  Selecting this option will configure the caches in write-through
	  mode, as opposed to the default write-back configuration.

	  Since there's sill some aliasing issues on SH-4, this option will
	  unfortunately still require the majority of flushing functions to
	  be implemented to deal with aliasing.

	  If unsure, say N.

config CACHE_OFF
	bool "Off"

endchoice

endmenu