# SPDX-License-Identifier: GPL-2.0
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menu "Memory management options"
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config MMU
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bool "Support for memory management hardware"
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depends on !CPU_SH2
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default y
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help
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Some SH processors (such as SH-2/SH-2A) lack an MMU. In order to
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boot on these systems, this option must not be set.
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On other systems (such as the SH-3 and 4) where an MMU exists,
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turning this off will boot the kernel on these machines with the
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MMU implicitly switched off.
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config PAGE_OFFSET
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hex
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default "0x80000000" if MMU
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default "0x00000000"
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config FORCE_MAX_ZONEORDER
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int "Maximum zone order"
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range 9 64 if PAGE_SIZE_16KB
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default "9" if PAGE_SIZE_16KB
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range 7 64 if PAGE_SIZE_64KB
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default "7" if PAGE_SIZE_64KB
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range 11 64
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default "14" if !MMU
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default "11"
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help
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The kernel memory allocator divides physically contiguous memory
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blocks into "zones", where each zone is a power of two number of
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pages. This option selects the largest power of two that the kernel
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keeps in the memory allocator. If you need to allocate very large
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blocks of physically contiguous memory, then you may need to
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increase this value.
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This config option is actually maximum order plus one. For example,
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a value of 11 means that the largest free memory block is 2^10 pages.
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The page size is not necessarily 4KB. Keep this in mind when
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choosing a value for this option.
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config MEMORY_START
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hex "Physical memory start address"
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default "0x08000000"
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help
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Computers built with Hitachi SuperH processors always
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map the ROM starting at address zero. But the processor
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does not specify the range that RAM takes.
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The physical memory (RAM) start address will be automatically
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set to 08000000. Other platforms, such as the Solution Engine
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boards typically map RAM at 0C000000.
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Tweak this only when porting to a new machine which does not
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already have a defconfig. Changing it from the known correct
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value on any of the known systems will only lead to disaster.
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config MEMORY_SIZE
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hex "Physical memory size"
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default "0x04000000"
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help
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This sets the default memory size assumed by your SH kernel. It can
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be overridden as normal by the 'mem=' argument on the kernel command
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line. If unsure, consult your board specifications or just leave it
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as 0x04000000 which was the default value before this became
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configurable.
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# Physical addressing modes
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config 29BIT
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def_bool !32BIT
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select UNCACHED_MAPPING
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config 32BIT
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bool
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default !MMU
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config PMB
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bool "Support 32-bit physical addressing through PMB"
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depends on MMU && CPU_SH4A && !CPU_SH4AL_DSP
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select 32BIT
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select UNCACHED_MAPPING
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help
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If you say Y here, physical addressing will be extended to
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32-bits through the SH-4A PMB. If this is not set, legacy
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29-bit physical addressing will be used.
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config X2TLB
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def_bool y
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depends on (CPU_SHX2 || CPU_SHX3) && MMU
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config VSYSCALL
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bool "Support vsyscall page"
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depends on MMU && (CPU_SH3 || CPU_SH4)
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default y
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help
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This will enable support for the kernel mapping a vDSO page
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in process space, and subsequently handing down the entry point
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to the libc through the ELF auxiliary vector.
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From the kernel side this is used for the signal trampoline.
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For systems with an MMU that can afford to give up a page,
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(the default value) say Y.
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config NUMA
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bool "Non Uniform Memory Access (NUMA) Support"
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depends on MMU && SYS_SUPPORTS_NUMA
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select ARCH_WANT_NUMA_VARIABLE_LOCALITY
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default n
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help
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Some SH systems have many various memories scattered around
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the address space, each with varying latencies. This enables
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support for these blocks by binding them to nodes and allowing
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memory policies to be used for prioritizing and controlling
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allocation behaviour.
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config NODES_SHIFT
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int
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default "3" if CPU_SUBTYPE_SHX3
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default "1"
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depends on NEED_MULTIPLE_NODES
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config ARCH_FLATMEM_ENABLE
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def_bool y
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depends on !NUMA
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config ARCH_SPARSEMEM_ENABLE
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def_bool y
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select SPARSEMEM_STATIC
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config ARCH_SPARSEMEM_DEFAULT
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def_bool y
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config ARCH_SELECT_MEMORY_MODEL
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def_bool y
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config ARCH_ENABLE_MEMORY_HOTPLUG
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def_bool y
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depends on SPARSEMEM && MMU
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config ARCH_ENABLE_MEMORY_HOTREMOVE
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def_bool y
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depends on SPARSEMEM && MMU
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config ARCH_MEMORY_PROBE
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def_bool y
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depends on MEMORY_HOTPLUG
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config IOREMAP_FIXED
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def_bool y
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depends on X2TLB
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config UNCACHED_MAPPING
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bool
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config HAVE_SRAM_POOL
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bool
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select GENERIC_ALLOCATOR
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choice
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prompt "Kernel page size"
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default PAGE_SIZE_4KB
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config PAGE_SIZE_4KB
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bool "4kB"
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help
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This is the default page size used by all SuperH CPUs.
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config PAGE_SIZE_8KB
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bool "8kB"
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depends on !MMU || X2TLB
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help
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This enables 8kB pages as supported by SH-X2 and later MMUs.
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config PAGE_SIZE_16KB
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bool "16kB"
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depends on !MMU
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help
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This enables 16kB pages on MMU-less SH systems.
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config PAGE_SIZE_64KB
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bool "64kB"
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depends on !MMU || CPU_SH4
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help
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This enables support for 64kB pages, possible on all SH-4
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CPUs and later.
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endchoice
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choice
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prompt "HugeTLB page size"
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depends on HUGETLB_PAGE
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default HUGETLB_PAGE_SIZE_1MB if PAGE_SIZE_64KB
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default HUGETLB_PAGE_SIZE_64K
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config HUGETLB_PAGE_SIZE_64K
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bool "64kB"
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depends on !PAGE_SIZE_64KB
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config HUGETLB_PAGE_SIZE_256K
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bool "256kB"
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depends on X2TLB
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config HUGETLB_PAGE_SIZE_1MB
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bool "1MB"
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config HUGETLB_PAGE_SIZE_4MB
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bool "4MB"
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depends on X2TLB
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config HUGETLB_PAGE_SIZE_64MB
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bool "64MB"
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depends on X2TLB
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endchoice
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config SCHED_MC
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bool "Multi-core scheduler support"
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depends on SMP
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default y
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help
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Multi-core scheduler support improves the CPU scheduler's decision
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making when dealing with multi-core CPU chips at a cost of slightly
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increased overhead in some places. If unsure say N here.
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endmenu
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menu "Cache configuration"
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config SH7705_CACHE_32KB
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bool "Enable 32KB cache size for SH7705"
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depends on CPU_SUBTYPE_SH7705
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default y
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choice
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prompt "Cache mode"
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default CACHE_WRITEBACK if CPU_SH2A || CPU_SH3 || CPU_SH4
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default CACHE_WRITETHROUGH if (CPU_SH2 && !CPU_SH2A)
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config CACHE_WRITEBACK
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bool "Write-back"
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config CACHE_WRITETHROUGH
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bool "Write-through"
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help
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Selecting this option will configure the caches in write-through
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mode, as opposed to the default write-back configuration.
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Since there's sill some aliasing issues on SH-4, this option will
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unfortunately still require the majority of flushing functions to
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be implemented to deal with aliasing.
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If unsure, say N.
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config CACHE_OFF
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bool "Off"
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endchoice
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endmenu
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