xref: /openbmc/linux/arch/sh/mm/Kconfig (revision b608dd67) 
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 ARCH_FORCE_MAX_ORDER
22	int "Order of maximal physically contiguous allocations"
23	default "8" if PAGE_SIZE_16KB
24	default "6" if PAGE_SIZE_64KB
25	default "13" if !MMU
26	default "10"
27	help
28	  The kernel page allocator limits the size of maximal physically
29	  contiguous allocations. The limit is called MAX_ORDER and it
30	  defines the maximal power of two of number of pages that can be
31	  allocated as a single contiguous block. This option allows
32	  overriding the default setting when ability to allocate very
33	  large blocks of physically contiguous memory is required.
34
35	  The page size is not necessarily 4KB. Keep this in mind when
36	  choosing a value for this option.
37
38	  Don't change if unsure.
39
40config MEMORY_START
41	hex "Physical memory start address"
42	default "0x08000000"
43	help
44	  Computers built with Hitachi SuperH processors always
45	  map the ROM starting at address zero.  But the processor
46	  does not specify the range that RAM takes.
47
48	  The physical memory (RAM) start address will be automatically
49	  set to 08000000. Other platforms, such as the Solution Engine
50	  boards typically map RAM at 0C000000.
51
52	  Tweak this only when porting to a new machine which does not
53	  already have a defconfig. Changing it from the known correct
54	  value on any of the known systems will only lead to disaster.
55
56config MEMORY_SIZE
57	hex "Physical memory size"
58	default "0x04000000"
59	help
60	  This sets the default memory size assumed by your SH kernel. It can
61	  be overridden as normal by the 'mem=' argument on the kernel command
62	  line. If unsure, consult your board specifications or just leave it
63	  as 0x04000000 which was the default value before this became
64	  configurable.
65
66# Physical addressing modes
67
68config 29BIT
69	def_bool !32BIT
70	select UNCACHED_MAPPING
71
72config 32BIT
73	bool
74	default !MMU
75
76config PMB
77	bool "Support 32-bit physical addressing through PMB"
78	depends on MMU && CPU_SH4A && !CPU_SH4AL_DSP
79	select 32BIT
80	select UNCACHED_MAPPING
81	help
82	  If you say Y here, physical addressing will be extended to
83	  32-bits through the SH-4A PMB. If this is not set, legacy
84	  29-bit physical addressing will be used.
85
86config X2TLB
87	def_bool y
88	depends on (CPU_SHX2 || CPU_SHX3) && MMU
89
90config VSYSCALL
91	bool "Support vsyscall page"
92	depends on MMU && (CPU_SH3 || CPU_SH4)
93	default y
94	help
95	  This will enable support for the kernel mapping a vDSO page
96	  in process space, and subsequently handing down the entry point
97	  to the libc through the ELF auxiliary vector.
98
99	  From the kernel side this is used for the signal trampoline.
100	  For systems with an MMU that can afford to give up a page,
101	  (the default value) say Y.
102
103config NUMA
104	bool "Non-Uniform Memory Access (NUMA) Support"
105	depends on MMU && SYS_SUPPORTS_NUMA
106	select ARCH_WANT_NUMA_VARIABLE_LOCALITY
107	default n
108	help
109	  Some SH systems have many various memories scattered around
110	  the address space, each with varying latencies. This enables
111	  support for these blocks by binding them to nodes and allowing
112	  memory policies to be used for prioritizing and controlling
113	  allocation behaviour.
114
115config NODES_SHIFT
116	int
117	default "3" if CPU_SUBTYPE_SHX3
118	default "1"
119	depends on NUMA
120
121config ARCH_FLATMEM_ENABLE
122	def_bool y
123	depends on !NUMA
124
125config ARCH_SPARSEMEM_ENABLE
126	def_bool y
127	select SPARSEMEM_STATIC
128
129config ARCH_SPARSEMEM_DEFAULT
130	def_bool y
131
132config ARCH_SELECT_MEMORY_MODEL
133	def_bool y
134
135config ARCH_MEMORY_PROBE
136	def_bool y
137	depends on MEMORY_HOTPLUG
138
139config IOREMAP_FIXED
140       def_bool y
141       depends on X2TLB
142
143config UNCACHED_MAPPING
144	bool
145
146config HAVE_SRAM_POOL
147	bool
148	select GENERIC_ALLOCATOR
149
150choice
151	prompt "Kernel page size"
152	default PAGE_SIZE_4KB
153
154config PAGE_SIZE_4KB
155	bool "4kB"
156	help
157	  This is the default page size used by all SuperH CPUs.
158
159config PAGE_SIZE_8KB
160	bool "8kB"
161	depends on !MMU || X2TLB
162	help
163	  This enables 8kB pages as supported by SH-X2 and later MMUs.
164
165config PAGE_SIZE_16KB
166	bool "16kB"
167	depends on !MMU
168	help
169	  This enables 16kB pages on MMU-less SH systems.
170
171config PAGE_SIZE_64KB
172	bool "64kB"
173	depends on !MMU || CPU_SH4
174	help
175	  This enables support for 64kB pages, possible on all SH-4
176	  CPUs and later.
177
178endchoice
179
180choice
181	prompt "HugeTLB page size"
182	depends on HUGETLB_PAGE
183	default HUGETLB_PAGE_SIZE_1MB if PAGE_SIZE_64KB
184	default HUGETLB_PAGE_SIZE_64K
185
186config HUGETLB_PAGE_SIZE_64K
187	bool "64kB"
188	depends on !PAGE_SIZE_64KB
189
190config HUGETLB_PAGE_SIZE_256K
191	bool "256kB"
192	depends on X2TLB
193
194config HUGETLB_PAGE_SIZE_1MB
195	bool "1MB"
196
197config HUGETLB_PAGE_SIZE_4MB
198	bool "4MB"
199	depends on X2TLB
200
201config HUGETLB_PAGE_SIZE_64MB
202	bool "64MB"
203	depends on X2TLB
204
205endchoice
206
207config SCHED_MC
208	bool "Multi-core scheduler support"
209	depends on SMP
210	default y
211	help
212	  Multi-core scheduler support improves the CPU scheduler's decision
213	  making when dealing with multi-core CPU chips at a cost of slightly
214	  increased overhead in some places. If unsure say N here.
215
216endmenu
217
218menu "Cache configuration"
219
220config SH7705_CACHE_32KB
221	bool "Enable 32KB cache size for SH7705"
222	depends on CPU_SUBTYPE_SH7705
223	default y
224
225choice
226	prompt "Cache mode"
227	default CACHE_WRITEBACK if CPU_SH2A || CPU_SH3 || CPU_SH4
228	default CACHE_WRITETHROUGH if (CPU_SH2 && !CPU_SH2A)
229
230config CACHE_WRITEBACK
231	bool "Write-back"
232
233config CACHE_WRITETHROUGH
234	bool "Write-through"
235	help
236	  Selecting this option will configure the caches in write-through
237	  mode, as opposed to the default write-back configuration.
238
239	  Since there's sill some aliasing issues on SH-4, this option will
240	  unfortunately still require the majority of flushing functions to
241	  be implemented to deal with aliasing.
242
243	  If unsure, say N.
244
245config CACHE_OFF
246	bool "Off"
247
248endchoice
249
250endmenu
251