xref: /openbmc/linux/arch/riscv/Kconfig (revision b9df3997)
1# SPDX-License-Identifier: GPL-2.0-only
2#
3# For a description of the syntax of this configuration file,
4# see Documentation/kbuild/kconfig-language.rst.
5#
6
7config 64BIT
8	bool
9
10config 32BIT
11	bool
12
13config RISCV
14	def_bool y
15	# even on 32-bit, physical (and DMA) addresses are > 32-bits
16	select PHYS_ADDR_T_64BIT
17	select OF
18	select OF_EARLY_FLATTREE
19	select OF_IRQ
20	select ARCH_HAS_BINFMT_FLAT
21	select ARCH_WANT_FRAME_POINTERS
22	select CLONE_BACKWARDS
23	select COMMON_CLK
24	select GENERIC_CLOCKEVENTS
25	select GENERIC_CPU_DEVICES
26	select GENERIC_IRQ_SHOW
27	select GENERIC_PCI_IOMAP
28	select GENERIC_SCHED_CLOCK
29	select GENERIC_STRNCPY_FROM_USER
30	select GENERIC_STRNLEN_USER
31	select GENERIC_SMP_IDLE_THREAD
32	select GENERIC_ATOMIC64 if !64BIT
33	select HAVE_ARCH_AUDITSYSCALL
34	select HAVE_ASM_MODVERSIONS
35	select HAVE_MEMBLOCK_NODE_MAP
36	select HAVE_DMA_CONTIGUOUS
37	select HAVE_FUTEX_CMPXCHG if FUTEX
38	select HAVE_PERF_EVENTS
39	select HAVE_PERF_REGS
40	select HAVE_PERF_USER_STACK_DUMP
41	select HAVE_SYSCALL_TRACEPOINTS
42	select IRQ_DOMAIN
43	select SPARSE_IRQ
44	select SYSCTL_EXCEPTION_TRACE
45	select HAVE_ARCH_TRACEHOOK
46	select HAVE_PCI
47	select MODULES_USE_ELF_RELA if MODULES
48	select MODULE_SECTIONS if MODULES
49	select THREAD_INFO_IN_TASK
50	select PCI_DOMAINS_GENERIC if PCI
51	select PCI_MSI if PCI
52	select RISCV_TIMER
53	select GENERIC_IRQ_MULTI_HANDLER
54	select GENERIC_ARCH_TOPOLOGY if SMP
55	select ARCH_HAS_PTE_SPECIAL
56	select ARCH_HAS_MMIOWB
57	select HAVE_EBPF_JIT if 64BIT
58	select EDAC_SUPPORT
59	select ARCH_HAS_GIGANTIC_PAGE
60	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
61	select SPARSEMEM_STATIC if 32BIT
62	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
63	select HAVE_ARCH_MMAP_RND_BITS
64
65config ARCH_MMAP_RND_BITS_MIN
66	default 18 if 64BIT
67	default 8
68
69# max bits determined by the following formula:
70#  VA_BITS - PAGE_SHIFT - 3
71config ARCH_MMAP_RND_BITS_MAX
72	default 24 if 64BIT # SV39 based
73	default 17
74
75config MMU
76	def_bool y
77
78config ZONE_DMA32
79	bool
80	default y if 64BIT
81
82config VA_BITS
83	int
84	default 32 if 32BIT
85	default 39 if 64BIT
86
87config PA_BITS
88	int
89	default 34 if 32BIT
90	default 56 if 64BIT
91
92config PAGE_OFFSET
93	hex
94	default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
95	default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
96	default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
97
98config ARCH_FLATMEM_ENABLE
99	def_bool y
100
101config ARCH_SPARSEMEM_ENABLE
102	def_bool y
103	select SPARSEMEM_VMEMMAP_ENABLE
104
105config ARCH_SELECT_MEMORY_MODEL
106	def_bool ARCH_SPARSEMEM_ENABLE
107
108config ARCH_WANT_GENERAL_HUGETLB
109	def_bool y
110
111config SYS_SUPPORTS_HUGETLBFS
112	def_bool y
113
114config STACKTRACE_SUPPORT
115	def_bool y
116
117config TRACE_IRQFLAGS_SUPPORT
118	def_bool y
119
120config GENERIC_BUG
121	def_bool y
122	depends on BUG
123	select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
124
125config GENERIC_BUG_RELATIVE_POINTERS
126	bool
127
128config GENERIC_CALIBRATE_DELAY
129	def_bool y
130
131config GENERIC_CSUM
132	def_bool y
133
134config GENERIC_HWEIGHT
135	def_bool y
136
137config FIX_EARLYCON_MEM
138	def_bool y
139
140config PGTABLE_LEVELS
141	int
142	default 3 if 64BIT
143	default 2
144
145source "arch/riscv/Kconfig.socs"
146
147menu "Platform type"
148
149choice
150	prompt "Base ISA"
151	default ARCH_RV64I
152	help
153	  This selects the base ISA that this kernel will target and must match
154	  the target platform.
155
156config ARCH_RV32I
157	bool "RV32I"
158	select 32BIT
159	select GENERIC_LIB_ASHLDI3
160	select GENERIC_LIB_ASHRDI3
161	select GENERIC_LIB_LSHRDI3
162	select GENERIC_LIB_UCMPDI2
163
164config ARCH_RV64I
165	bool "RV64I"
166	select 64BIT
167	select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000
168	select HAVE_FUNCTION_TRACER
169	select HAVE_FUNCTION_GRAPH_TRACER
170	select HAVE_FTRACE_MCOUNT_RECORD
171	select HAVE_DYNAMIC_FTRACE
172	select HAVE_DYNAMIC_FTRACE_WITH_REGS
173	select SWIOTLB
174
175endchoice
176
177# We must be able to map all physical memory into the kernel, but the compiler
178# is still a bit more efficient when generating code if it's setup in a manner
179# such that it can only map 2GiB of memory.
180choice
181	prompt "Kernel Code Model"
182	default CMODEL_MEDLOW if 32BIT
183	default CMODEL_MEDANY if 64BIT
184
185	config CMODEL_MEDLOW
186		bool "medium low code model"
187	config CMODEL_MEDANY
188		bool "medium any code model"
189endchoice
190
191config MODULE_SECTIONS
192	bool
193	select HAVE_MOD_ARCH_SPECIFIC
194
195choice
196	prompt "Maximum Physical Memory"
197	default MAXPHYSMEM_2GB if 32BIT
198	default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
199	default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY
200
201	config MAXPHYSMEM_2GB
202		bool "2GiB"
203	config MAXPHYSMEM_128GB
204		depends on 64BIT && CMODEL_MEDANY
205		bool "128GiB"
206endchoice
207
208
209config SMP
210	bool "Symmetric Multi-Processing"
211	help
212	  This enables support for systems with more than one CPU.  If
213	  you say N here, the kernel will run on single and
214	  multiprocessor machines, but will use only one CPU of a
215	  multiprocessor machine. If you say Y here, the kernel will run
216	  on many, but not all, single processor machines. On a single
217	  processor machine, the kernel will run faster if you say N
218	  here.
219
220	  If you don't know what to do here, say N.
221
222config NR_CPUS
223	int "Maximum number of CPUs (2-32)"
224	range 2 32
225	depends on SMP
226	default "8"
227
228choice
229	prompt "CPU Tuning"
230	default TUNE_GENERIC
231
232config TUNE_GENERIC
233	bool "generic"
234
235endchoice
236
237config RISCV_ISA_C
238	bool "Emit compressed instructions when building Linux"
239	default y
240	help
241	   Adds "C" to the ISA subsets that the toolchain is allowed to emit
242	   when building Linux, which results in compressed instructions in the
243	   Linux binary.
244
245	   If you don't know what to do here, say Y.
246
247menu "supported PMU type"
248	depends on PERF_EVENTS
249
250config RISCV_BASE_PMU
251	bool "Base Performance Monitoring Unit"
252	def_bool y
253	help
254	  A base PMU that serves as a reference implementation and has limited
255	  feature of perf.  It can run on any RISC-V machines so serves as the
256	  fallback, but this option can also be disable to reduce kernel size.
257
258endmenu
259
260config FPU
261	bool "FPU support"
262	default y
263	help
264	  Say N here if you want to disable all floating-point related procedure
265	  in the kernel.
266
267	  If you don't know what to do here, say Y.
268
269endmenu
270
271menu "Kernel features"
272
273source "kernel/Kconfig.hz"
274
275endmenu
276
277menu "Boot options"
278
279config CMDLINE
280	string "Built-in kernel command line"
281	help
282	  For most platforms, the arguments for the kernel's command line
283	  are provided at run-time, during boot. However, there are cases
284	  where either no arguments are being provided or the provided
285	  arguments are insufficient or even invalid.
286
287	  When that occurs, it is possible to define a built-in command
288	  line here and choose how the kernel should use it later on.
289
290choice
291	prompt "Built-in command line usage" if CMDLINE != ""
292	default CMDLINE_FALLBACK
293	help
294	  Choose how the kernel will handle the provided built-in command
295	  line.
296
297config CMDLINE_FALLBACK
298	bool "Use bootloader kernel arguments if available"
299	help
300	  Use the built-in command line as fallback in case we get nothing
301	  during boot. This is the default behaviour.
302
303config CMDLINE_EXTEND
304	bool "Extend bootloader kernel arguments"
305	help
306	  The command-line arguments provided during boot will be
307	  appended to the built-in command line. This is useful in
308	  cases where the provided arguments are insufficient and
309	  you don't want to or cannot modify them.
310
311
312config CMDLINE_FORCE
313	bool "Always use the default kernel command string"
314	help
315	  Always use the built-in command line, even if we get one during
316	  boot. This is useful in case you need to override the provided
317	  command line on systems where you don't have or want control
318	  over it.
319
320endchoice
321
322endmenu
323
324menu "Power management options"
325
326source "kernel/power/Kconfig"
327
328endmenu
329