tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1# SPDX-License-Identifier: GPL-2.0
2menu "Memory management options"
3
4config MMU
5 bool "Support for memory management hardware"
6 depends on !CPU_SH2
7 default y
8 help
9 Some SH processors (such as SH-2/SH-2A) lack an MMU. In order to
10 boot on these systems, this option must not be set.
11
12 On other systems (such as the SH-3 and 4) where an MMU exists,
13 turning this off will boot the kernel on these machines with the
14 MMU implicitly switched off.
15
16config PAGE_OFFSET
17 hex
18 default "0x80000000" if MMU
19 default "0x00000000"
20
21config FORCE_MAX_ZONEORDER
22 int "Maximum zone order"
23 range 9 64 if PAGE_SIZE_16KB
24 default "9" if PAGE_SIZE_16KB
25 range 7 64 if PAGE_SIZE_64KB
26 default "7" if PAGE_SIZE_64KB
27 range 11 64
28 default "14" if !MMU
29 default "11"
30 help
31 The kernel memory allocator divides physically contiguous memory
32 blocks into "zones", where each zone is a power of two number of
33 pages. This option selects the largest power of two that the kernel
34 keeps in the memory allocator. If you need to allocate very large
35 blocks of physically contiguous memory, then you may need to
36 increase this value.
37
38 This config option is actually maximum order plus one. For example,
39 a value of 11 means that the largest free memory block is 2^10 pages.
40
41 The page size is not necessarily 4KB. Keep this in mind when
42 choosing a value for this option.
43
44config MEMORY_START
45 hex "Physical memory start address"
46 default "0x08000000"
47 help
48 Computers built with Hitachi SuperH processors always
49 map the ROM starting at address zero. But the processor
50 does not specify the range that RAM takes.
51
52 The physical memory (RAM) start address will be automatically
53 set to 08000000. Other platforms, such as the Solution Engine
54 boards typically map RAM at 0C000000.
55
56 Tweak this only when porting to a new machine which does not
57 already have a defconfig. Changing it from the known correct
58 value on any of the known systems will only lead to disaster.
59
60config MEMORY_SIZE
61 hex "Physical memory size"
62 default "0x04000000"
63 help
64 This sets the default memory size assumed by your SH kernel. It can
65 be overridden as normal by the 'mem=' argument on the kernel command
66 line. If unsure, consult your board specifications or just leave it
67 as 0x04000000 which was the default value before this became
68 configurable.
69
70# Physical addressing modes
71
72config 29BIT
73 def_bool !32BIT
74 select UNCACHED_MAPPING
75
76config 32BIT
77 bool
78 default !MMU
79
80config PMB
81 bool "Support 32-bit physical addressing through PMB"
82 depends on MMU && CPU_SH4A && !CPU_SH4AL_DSP
83 select 32BIT
84 select UNCACHED_MAPPING
85 help
86 If you say Y here, physical addressing will be extended to
87 32-bits through the SH-4A PMB. If this is not set, legacy
88 29-bit physical addressing will be used.
89
90config X2TLB
91 def_bool y
92 depends on (CPU_SHX2 || CPU_SHX3) && MMU
93
94config VSYSCALL
95 bool "Support vsyscall page"
96 depends on MMU && (CPU_SH3 || CPU_SH4)
97 default y
98 help
99 This will enable support for the kernel mapping a vDSO page
100 in process space, and subsequently handing down the entry point
101 to the libc through the ELF auxiliary vector.
102
103 From the kernel side this is used for the signal trampoline.
104 For systems with an MMU that can afford to give up a page,
105 (the default value) say Y.
106
107config NUMA
108 bool "Non Uniform Memory Access (NUMA) Support"
109 depends on MMU && SYS_SUPPORTS_NUMA
110 select ARCH_WANT_NUMA_VARIABLE_LOCALITY
111 default n
112 help
113 Some SH systems have many various memories scattered around
114 the address space, each with varying latencies. This enables
115 support for these blocks by binding them to nodes and allowing
116 memory policies to be used for prioritizing and controlling
117 allocation behaviour.
118
119config NODES_SHIFT
120 int
121 default "3" if CPU_SUBTYPE_SHX3
122 default "1"
123 depends on NEED_MULTIPLE_NODES
124
125config ARCH_FLATMEM_ENABLE
126 def_bool y
127 depends on !NUMA
128
129config ARCH_SPARSEMEM_ENABLE
130 def_bool y
131 select SPARSEMEM_STATIC
132
133config ARCH_SPARSEMEM_DEFAULT
134 def_bool y
135
136config ARCH_SELECT_MEMORY_MODEL
137 def_bool y
138
139config ARCH_ENABLE_MEMORY_HOTPLUG
140 def_bool y
141 depends on SPARSEMEM && MMU
142
143config ARCH_ENABLE_MEMORY_HOTREMOVE
144 def_bool y
145 depends on SPARSEMEM && MMU
146
147config ARCH_MEMORY_PROBE
148 def_bool y
149 depends on MEMORY_HOTPLUG
150
151config IOREMAP_FIXED
152 def_bool y
153 depends on X2TLB
154
155config UNCACHED_MAPPING
156 bool
157
158config HAVE_SRAM_POOL
159 bool
160 select GENERIC_ALLOCATOR
161
162choice
163 prompt "Kernel page size"
164 default PAGE_SIZE_4KB
165
166config PAGE_SIZE_4KB
167 bool "4kB"
168 help
169 This is the default page size used by all SuperH CPUs.
170
171config PAGE_SIZE_8KB
172 bool "8kB"
173 depends on !MMU || X2TLB
174 help
175 This enables 8kB pages as supported by SH-X2 and later MMUs.
176
177config PAGE_SIZE_16KB
178 bool "16kB"
179 depends on !MMU
180 help
181 This enables 16kB pages on MMU-less SH systems.
182
183config PAGE_SIZE_64KB
184 bool "64kB"
185 depends on !MMU || CPU_SH4
186 help
187 This enables support for 64kB pages, possible on all SH-4
188 CPUs and later.
189
190endchoice
191
192choice
193 prompt "HugeTLB page size"
194 depends on HUGETLB_PAGE
195 default HUGETLB_PAGE_SIZE_1MB if PAGE_SIZE_64KB
196 default HUGETLB_PAGE_SIZE_64K
197
198config HUGETLB_PAGE_SIZE_64K
199 bool "64kB"
200 depends on !PAGE_SIZE_64KB
201
202config HUGETLB_PAGE_SIZE_256K
203 bool "256kB"
204 depends on X2TLB
205
206config HUGETLB_PAGE_SIZE_1MB
207 bool "1MB"
208
209config HUGETLB_PAGE_SIZE_4MB
210 bool "4MB"
211 depends on X2TLB
212
213config HUGETLB_PAGE_SIZE_64MB
214 bool "64MB"
215 depends on X2TLB
216
217endchoice
218
219config SCHED_MC
220 bool "Multi-core scheduler support"
221 depends on SMP
222 default y
223 help
224 Multi-core scheduler support improves the CPU scheduler's decision
225 making when dealing with multi-core CPU chips at a cost of slightly
226 increased overhead in some places. If unsure say N here.
227
228endmenu
229
230menu "Cache configuration"
231
232config SH7705_CACHE_32KB
233 bool "Enable 32KB cache size for SH7705"
234 depends on CPU_SUBTYPE_SH7705
235 default y
236
237choice
238 prompt "Cache mode"
239 default CACHE_WRITEBACK if CPU_SH2A || CPU_SH3 || CPU_SH4
240 default CACHE_WRITETHROUGH if (CPU_SH2 && !CPU_SH2A)
241
242config CACHE_WRITEBACK
243 bool "Write-back"
244
245config CACHE_WRITETHROUGH
246 bool "Write-through"
247 help
248 Selecting this option will configure the caches in write-through
249 mode, as opposed to the default write-back configuration.
250
251 Since there's sill some aliasing issues on SH-4, this option will
252 unfortunately still require the majority of flushing functions to
253 be implemented to deal with aliasing.
254
255 If unsure, say N.
256
257config CACHE_OFF
258 bool "Off"
259
260endchoice
261
262endmenu