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.txt.
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_WANT_FRAME_POINTERS
21 select CLONE_BACKWARDS
23 select GENERIC_CLOCKEVENTS
24 select GENERIC_CPU_DEVICES
25 select GENERIC_IRQ_SHOW
26 select GENERIC_PCI_IOMAP
27 select GENERIC_SCHED_CLOCK
28 select GENERIC_STRNCPY_FROM_USER
29 select GENERIC_STRNLEN_USER
30 select GENERIC_SMP_IDLE_THREAD
31 select GENERIC_ATOMIC64 if !64BIT
32 select HAVE_ARCH_AUDITSYSCALL
33 select HAVE_MEMBLOCK_NODE_MAP
34 select HAVE_DMA_CONTIGUOUS
35 select HAVE_FUTEX_CMPXCHG if FUTEX
36 select HAVE_PERF_EVENTS
37 select HAVE_SYSCALL_TRACEPOINTS
40 select SYSCTL_EXCEPTION_TRACE
41 select HAVE_ARCH_TRACEHOOK
43 select MODULES_USE_ELF_RELA if MODULES
44 select MODULE_SECTIONS if MODULES
45 select THREAD_INFO_IN_TASK
46 select PCI_DOMAINS_GENERIC if PCI
49 select GENERIC_IRQ_MULTI_HANDLER
50 select ARCH_HAS_PTE_SPECIAL
51 select ARCH_HAS_MMIOWB
52 select HAVE_EBPF_JIT if 64BIT
64 default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
65 default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
66 default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
68 config STACKTRACE_SUPPORT
71 config TRACE_IRQFLAGS_SUPPORT
77 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
79 config GENERIC_BUG_RELATIVE_POINTERS
82 config GENERIC_CALIBRATE_DELAY
88 config GENERIC_HWEIGHT
91 config FIX_EARLYCON_MEM
105 This selects the base ISA that this kernel will target and must match
111 select GENERIC_LIB_ASHLDI3
112 select GENERIC_LIB_ASHRDI3
113 select GENERIC_LIB_LSHRDI3
114 select GENERIC_LIB_UCMPDI2
119 select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000
120 select HAVE_FUNCTION_TRACER
121 select HAVE_FUNCTION_GRAPH_TRACER
122 select HAVE_FTRACE_MCOUNT_RECORD
123 select HAVE_DYNAMIC_FTRACE
124 select HAVE_DYNAMIC_FTRACE_WITH_REGS
129 # We must be able to map all physical memory into the kernel, but the compiler
130 # is still a bit more efficient when generating code if it's setup in a manner
131 # such that it can only map 2GiB of memory.
133 prompt "Kernel Code Model"
134 default CMODEL_MEDLOW if 32BIT
135 default CMODEL_MEDANY if 64BIT
138 bool "medium low code model"
140 bool "medium any code model"
143 config MODULE_SECTIONS
145 select HAVE_MOD_ARCH_SPECIFIC
148 prompt "Maximum Physical Memory"
149 default MAXPHYSMEM_2GB if 32BIT
150 default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
151 default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY
153 config MAXPHYSMEM_2GB
155 config MAXPHYSMEM_128GB
156 depends on 64BIT && CMODEL_MEDANY
162 bool "Symmetric Multi-Processing"
164 This enables support for systems with more than one CPU. If
165 you say N here, the kernel will run on single and
166 multiprocessor machines, but will use only one CPU of a
167 multiprocessor machine. If you say Y here, the kernel will run
168 on many, but not all, single processor machines. On a single
169 processor machine, the kernel will run faster if you say N
172 If you don't know what to do here, say N.
175 int "Maximum number of CPUs (2-32)"
190 bool "Emit compressed instructions when building Linux"
193 Adds "C" to the ISA subsets that the toolchain is allowed to emit
194 when building Linux, which results in compressed instructions in the
197 If you don't know what to do here, say Y.
199 menu "supported PMU type"
200 depends on PERF_EVENTS
202 config RISCV_BASE_PMU
203 bool "Base Performance Monitoring Unit"
206 A base PMU that serves as a reference implementation and has limited
207 feature of perf. It can run on any RISC-V machines so serves as the
208 fallback, but this option can also be disable to reduce kernel size.
216 Say N here if you want to disable all floating-point related procedure
219 If you don't know what to do here, say Y.
223 menu "Kernel features"
225 source "kernel/Kconfig.hz"
232 string "Built-in kernel command line"
234 For most platforms, the arguments for the kernel's command line
235 are provided at run-time, during boot. However, there are cases
236 where either no arguments are being provided or the provided
237 arguments are insufficient or even invalid.
239 When that occurs, it is possible to define a built-in command
240 line here and choose how the kernel should use it later on.
243 prompt "Built-in command line usage" if CMDLINE != ""
244 default CMDLINE_FALLBACK
246 Choose how the kernel will handle the provided built-in command
249 config CMDLINE_FALLBACK
250 bool "Use bootloader kernel arguments if available"
252 Use the built-in command line as fallback in case we get nothing
253 during boot. This is the default behaviour.
255 config CMDLINE_EXTEND
256 bool "Extend bootloader kernel arguments"
258 The command-line arguments provided during boot will be
259 appended to the built-in command line. This is useful in
260 cases where the provided arguments are insufficient and
261 you don't want to or cannot modify them.
265 bool "Always use the default kernel command string"
267 Always use the built-in command line, even if we get one during
268 boot. This is useful in case you need to override the provided
269 command line on systems where you don't have or want control
276 menu "Power management options"
278 source "kernel/power/Kconfig"