1 # SPDX-License-Identifier: GPL-2.0-only
3 # For a description of the syntax of this configuration file,
4 # see Documentation/kbuild/kconfig-language.rst.
15 # even on 32-bit, physical (and DMA) addresses are > 32-bits
16 select PHYS_ADDR_T_64BIT
18 select OF_EARLY_FLATTREE
20 select ARCH_HAS_BINFMT_FLAT
21 select ARCH_WANT_FRAME_POINTERS
22 select CLONE_BACKWARDS
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 if MMU
30 select GENERIC_STRNLEN_USER if MMU
31 select GENERIC_SMP_IDLE_THREAD
32 select GENERIC_ATOMIC64 if !64BIT
33 select GENERIC_IOREMAP
34 select HAVE_ARCH_AUDITSYSCALL
35 select HAVE_ARCH_SECCOMP_FILTER
36 select HAVE_ASM_MODVERSIONS
37 select HAVE_MEMBLOCK_NODE_MAP
38 select HAVE_DMA_CONTIGUOUS if MMU
39 select HAVE_FUTEX_CMPXCHG if FUTEX
40 select HAVE_PERF_EVENTS
42 select HAVE_PERF_USER_STACK_DUMP
43 select HAVE_SYSCALL_TRACEPOINTS
46 select SYSCTL_EXCEPTION_TRACE
47 select HAVE_ARCH_TRACEHOOK
49 select MODULES_USE_ELF_RELA if MODULES
50 select MODULE_SECTIONS if MODULES
51 select THREAD_INFO_IN_TASK
52 select PCI_DOMAINS_GENERIC if PCI
55 select UACCESS_MEMCPY if !MMU
56 select GENERIC_IRQ_MULTI_HANDLER
57 select GENERIC_ARCH_TOPOLOGY if SMP
58 select ARCH_HAS_PTE_SPECIAL
59 select ARCH_HAS_MMIOWB
60 select HAVE_EBPF_JIT if 64BIT
62 select ARCH_HAS_GIGANTIC_PAGE
63 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
64 select SPARSEMEM_STATIC if 32BIT
65 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
66 select HAVE_ARCH_MMAP_RND_BITS if MMU
67 select ARCH_HAS_GCOV_PROFILE_ALL
68 select HAVE_COPY_THREAD_TLS
69 select HAVE_ARCH_KASAN if MMU && 64BIT
71 config ARCH_MMAP_RND_BITS_MIN
75 # max bits determined by the following formula:
76 # VA_BITS - PAGE_SHIFT - 3
77 config ARCH_MMAP_RND_BITS_MAX
78 default 24 if 64BIT # SV39 based
81 # set if we run in machine mode, cleared if we run in supervisor mode
86 # set if we are running in S-mode and can use SBI calls
89 depends on !RISCV_M_MODE
93 bool "MMU-based Paged Memory Management Support"
96 Select if you want MMU-based virtualised addressing space
97 support by paged memory management. If unsure, say 'Y'.
115 default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
116 default 0x80000000 if 64BIT && !MMU
117 default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
118 default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
120 config ARCH_FLATMEM_ENABLE
123 config ARCH_SPARSEMEM_ENABLE
125 select SPARSEMEM_VMEMMAP_ENABLE
127 config ARCH_SELECT_MEMORY_MODEL
128 def_bool ARCH_SPARSEMEM_ENABLE
130 config ARCH_WANT_GENERAL_HUGETLB
133 config SYS_SUPPORTS_HUGETLBFS
136 config STACKTRACE_SUPPORT
139 config TRACE_IRQFLAGS_SUPPORT
145 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
147 config GENERIC_BUG_RELATIVE_POINTERS
150 config GENERIC_CALIBRATE_DELAY
156 config GENERIC_HWEIGHT
159 config FIX_EARLYCON_MEM
162 config PGTABLE_LEVELS
167 source "arch/riscv/Kconfig.socs"
175 This selects the base ISA that this kernel will target and must match
181 select GENERIC_LIB_ASHLDI3
182 select GENERIC_LIB_ASHRDI3
183 select GENERIC_LIB_LSHRDI3
184 select GENERIC_LIB_UCMPDI2
190 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && GCC_VERSION >= 50000
191 select HAVE_FUNCTION_TRACER
192 select HAVE_FUNCTION_GRAPH_TRACER
193 select HAVE_FTRACE_MCOUNT_RECORD
194 select HAVE_DYNAMIC_FTRACE if MMU
195 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
196 select SWIOTLB if MMU
200 # We must be able to map all physical memory into the kernel, but the compiler
201 # is still a bit more efficient when generating code if it's setup in a manner
202 # such that it can only map 2GiB of memory.
204 prompt "Kernel Code Model"
205 default CMODEL_MEDLOW if 32BIT
206 default CMODEL_MEDANY if 64BIT
209 bool "medium low code model"
211 bool "medium any code model"
214 config MODULE_SECTIONS
216 select HAVE_MOD_ARCH_SPECIFIC
219 prompt "Maximum Physical Memory"
220 default MAXPHYSMEM_2GB if 32BIT
221 default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
222 default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY
224 config MAXPHYSMEM_2GB
226 config MAXPHYSMEM_128GB
227 depends on 64BIT && CMODEL_MEDANY
233 bool "Symmetric Multi-Processing"
235 This enables support for systems with more than one CPU. If
236 you say N here, the kernel will run on single and
237 multiprocessor machines, but will use only one CPU of a
238 multiprocessor machine. If you say Y here, the kernel will run
239 on many, but not all, single processor machines. On a single
240 processor machine, the kernel will run faster if you say N
243 If you don't know what to do here, say N.
246 int "Maximum number of CPUs (2-32)"
261 bool "Emit compressed instructions when building Linux"
264 Adds "C" to the ISA subsets that the toolchain is allowed to emit
265 when building Linux, which results in compressed instructions in the
268 If you don't know what to do here, say Y.
270 menu "supported PMU type"
271 depends on PERF_EVENTS
273 config RISCV_BASE_PMU
274 bool "Base Performance Monitoring Unit"
277 A base PMU that serves as a reference implementation and has limited
278 feature of perf. It can run on any RISC-V machines so serves as the
279 fallback, but this option can also be disable to reduce kernel size.
287 Say N here if you want to disable all floating-point related procedure
290 If you don't know what to do here, say Y.
294 menu "Kernel features"
296 source "kernel/Kconfig.hz"
299 bool "Enable seccomp to safely compute untrusted bytecode"
301 This kernel feature is useful for number crunching applications
302 that may need to compute untrusted bytecode during their
303 execution. By using pipes or other transports made available to
304 the process as file descriptors supporting the read/write
305 syscalls, it's possible to isolate those applications in
306 their own address space using seccomp. Once seccomp is
307 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
308 and the task is only allowed to execute a few safe syscalls
309 defined by each seccomp mode.
316 string "Built-in kernel command line"
318 For most platforms, the arguments for the kernel's command line
319 are provided at run-time, during boot. However, there are cases
320 where either no arguments are being provided or the provided
321 arguments are insufficient or even invalid.
323 When that occurs, it is possible to define a built-in command
324 line here and choose how the kernel should use it later on.
327 prompt "Built-in command line usage" if CMDLINE != ""
328 default CMDLINE_FALLBACK
330 Choose how the kernel will handle the provided built-in command
333 config CMDLINE_FALLBACK
334 bool "Use bootloader kernel arguments if available"
336 Use the built-in command line as fallback in case we get nothing
337 during boot. This is the default behaviour.
339 config CMDLINE_EXTEND
340 bool "Extend bootloader kernel arguments"
342 The command-line arguments provided during boot will be
343 appended to the built-in command line. This is useful in
344 cases where the provided arguments are insufficient and
345 you don't want to or cannot modify them.
349 bool "Always use the default kernel command string"
351 Always use the built-in command line, even if we get one during
352 boot. This is useful in case you need to override the provided
353 command line on systems where you don't have or want control
360 menu "Power management options"
362 source "kernel/power/Kconfig"