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
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_MEMBLOCK_NODE_MAP
35 select HAVE_DMA_CONTIGUOUS
36 select HAVE_FUTEX_CMPXCHG if FUTEX
37 select HAVE_PERF_EVENTS
38 select HAVE_SYSCALL_TRACEPOINTS
41 select SYSCTL_EXCEPTION_TRACE
42 select HAVE_ARCH_TRACEHOOK
44 select MODULES_USE_ELF_RELA if MODULES
45 select MODULE_SECTIONS if MODULES
46 select THREAD_INFO_IN_TASK
47 select PCI_DOMAINS_GENERIC if PCI
50 select GENERIC_IRQ_MULTI_HANDLER
51 select ARCH_HAS_PTE_SPECIAL
52 select ARCH_HAS_MMIOWB
53 select HAVE_EBPF_JIT if 64BIT
65 default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
66 default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
67 default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
69 config STACKTRACE_SUPPORT
72 config TRACE_IRQFLAGS_SUPPORT
78 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
80 config GENERIC_BUG_RELATIVE_POINTERS
83 config GENERIC_CALIBRATE_DELAY
89 config GENERIC_HWEIGHT
92 config FIX_EARLYCON_MEM
106 This selects the base ISA that this kernel will target and must match
112 select GENERIC_LIB_ASHLDI3
113 select GENERIC_LIB_ASHRDI3
114 select GENERIC_LIB_LSHRDI3
115 select GENERIC_LIB_UCMPDI2
120 select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000
121 select HAVE_FUNCTION_TRACER
122 select HAVE_FUNCTION_GRAPH_TRACER
123 select HAVE_FTRACE_MCOUNT_RECORD
124 select HAVE_DYNAMIC_FTRACE
125 select HAVE_DYNAMIC_FTRACE_WITH_REGS
130 # We must be able to map all physical memory into the kernel, but the compiler
131 # is still a bit more efficient when generating code if it's setup in a manner
132 # such that it can only map 2GiB of memory.
134 prompt "Kernel Code Model"
135 default CMODEL_MEDLOW if 32BIT
136 default CMODEL_MEDANY if 64BIT
139 bool "medium low code model"
141 bool "medium any code model"
144 config MODULE_SECTIONS
146 select HAVE_MOD_ARCH_SPECIFIC
149 prompt "Maximum Physical Memory"
150 default MAXPHYSMEM_2GB if 32BIT
151 default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
152 default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY
154 config MAXPHYSMEM_2GB
156 config MAXPHYSMEM_128GB
157 depends on 64BIT && CMODEL_MEDANY
163 bool "Symmetric Multi-Processing"
165 This enables support for systems with more than one CPU. If
166 you say N here, the kernel will run on single and
167 multiprocessor machines, but will use only one CPU of a
168 multiprocessor machine. If you say Y here, the kernel will run
169 on many, but not all, single processor machines. On a single
170 processor machine, the kernel will run faster if you say N
173 If you don't know what to do here, say N.
176 int "Maximum number of CPUs (2-32)"
191 bool "Emit compressed instructions when building Linux"
194 Adds "C" to the ISA subsets that the toolchain is allowed to emit
195 when building Linux, which results in compressed instructions in the
198 If you don't know what to do here, say Y.
200 menu "supported PMU type"
201 depends on PERF_EVENTS
203 config RISCV_BASE_PMU
204 bool "Base Performance Monitoring Unit"
207 A base PMU that serves as a reference implementation and has limited
208 feature of perf. It can run on any RISC-V machines so serves as the
209 fallback, but this option can also be disable to reduce kernel size.
217 Say N here if you want to disable all floating-point related procedure
220 If you don't know what to do here, say Y.
224 menu "Kernel features"
226 source "kernel/Kconfig.hz"
233 string "Built-in kernel command line"
235 For most platforms, the arguments for the kernel's command line
236 are provided at run-time, during boot. However, there are cases
237 where either no arguments are being provided or the provided
238 arguments are insufficient or even invalid.
240 When that occurs, it is possible to define a built-in command
241 line here and choose how the kernel should use it later on.
244 prompt "Built-in command line usage" if CMDLINE != ""
245 default CMDLINE_FALLBACK
247 Choose how the kernel will handle the provided built-in command
250 config CMDLINE_FALLBACK
251 bool "Use bootloader kernel arguments if available"
253 Use the built-in command line as fallback in case we get nothing
254 during boot. This is the default behaviour.
256 config CMDLINE_EXTEND
257 bool "Extend bootloader kernel arguments"
259 The command-line arguments provided during boot will be
260 appended to the built-in command line. This is useful in
261 cases where the provided arguments are insufficient and
262 you don't want to or cannot modify them.
266 bool "Always use the default kernel command string"
268 Always use the built-in command line, even if we get one during
269 boot. This is useful in case you need to override the provided
270 command line on systems where you don't have or want control
277 menu "Power management options"
279 source "kernel/power/Kconfig"