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 select ACPI_GENERIC_GSI if ACPI
16 select ACPI_REDUCED_HARDWARE_ONLY if ACPI
17 select ARCH_DMA_DEFAULT_COHERENT
18 select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
19 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
20 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
21 select ARCH_HAS_BINFMT_FLAT
22 select ARCH_HAS_CURRENT_STACK_POINTER
23 select ARCH_HAS_DEBUG_VIRTUAL if MMU
24 select ARCH_HAS_DEBUG_VM_PGTABLE
25 select ARCH_HAS_DEBUG_WX
26 select ARCH_HAS_FORTIFY_SOURCE
27 select ARCH_HAS_GCOV_PROFILE_ALL
28 select ARCH_HAS_GIGANTIC_PAGE
30 select ARCH_HAS_MEMBARRIER_CALLBACKS
31 select ARCH_HAS_MEMBARRIER_SYNC_CORE
32 select ARCH_HAS_MMIOWB
33 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
34 select ARCH_HAS_PMEM_API
35 select ARCH_HAS_PREPARE_SYNC_CORE_CMD
36 select ARCH_HAS_PTE_SPECIAL
37 select ARCH_HAS_SET_DIRECT_MAP if MMU
38 select ARCH_HAS_SET_MEMORY if MMU
39 select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
40 select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
41 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
42 select ARCH_HAS_SYSCALL_WRAPPER
43 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
44 select ARCH_HAS_UBSAN_SANITIZE_ALL
45 select ARCH_HAS_VDSO_DATA
46 select ARCH_KEEP_MEMBLOCK if ACPI
47 select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
48 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
50 select ARCH_SUPPORTS_ATOMIC_RMW
51 select ARCH_SUPPORTS_CFI_CLANG
52 select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
53 select ARCH_SUPPORTS_HUGETLBFS if MMU
54 # LLD >= 14: https://github.com/llvm/llvm-project/issues/50505
55 select ARCH_SUPPORTS_LTO_CLANG if LLD_VERSION >= 140000
56 select ARCH_SUPPORTS_LTO_CLANG_THIN if LLD_VERSION >= 140000
57 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
58 select ARCH_SUPPORTS_PER_VMA_LOCK if MMU
59 select ARCH_SUPPORTS_SHADOW_CALL_STACK if HAVE_SHADOW_CALL_STACK
60 select ARCH_USE_MEMTEST
61 select ARCH_USE_QUEUED_RWLOCKS
62 select ARCH_USES_CFI_TRAPS if CFI_CLANG
63 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP && MMU
64 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
65 select ARCH_WANT_FRAME_POINTERS
66 select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
67 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
68 select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
69 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
70 select ARCH_WANTS_NO_INSTR
71 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
72 select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
73 select BUILDTIME_TABLE_SORT if MMU
74 select CLINT_TIMER if !MMU
75 select CLONE_BACKWARDS
77 select CPU_PM if CPU_IDLE || HIBERNATION || SUSPEND
79 select FRAME_POINTER if PERF_EVENTS || (FUNCTION_TRACER && !DYNAMIC_FTRACE)
80 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if DYNAMIC_FTRACE
81 select GENERIC_ARCH_TOPOLOGY
82 select GENERIC_ATOMIC64 if !64BIT
83 select GENERIC_CLOCKEVENTS_BROADCAST if SMP
84 select GENERIC_CPU_DEVICES
85 select GENERIC_EARLY_IOREMAP
87 select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
88 select GENERIC_IDLE_POLL_SETUP
89 select GENERIC_IOREMAP if MMU
90 select GENERIC_IRQ_IPI if SMP
91 select GENERIC_IRQ_IPI_MUX if SMP
92 select GENERIC_IRQ_MULTI_HANDLER
93 select GENERIC_IRQ_SHOW
94 select GENERIC_IRQ_SHOW_LEVEL
95 select GENERIC_LIB_DEVMEM_IS_ALLOWED
96 select GENERIC_PCI_IOMAP
97 select GENERIC_PTDUMP if MMU
98 select GENERIC_SCHED_CLOCK
99 select GENERIC_SMP_IDLE_THREAD
100 select GENERIC_TIME_VSYSCALL if MMU && 64BIT
101 select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
102 select HARDIRQS_SW_RESEND
103 select HAS_IOPORT if MMU
104 select HAVE_ARCH_AUDITSYSCALL
105 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
106 select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT && !XIP_KERNEL
107 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
108 select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
109 select HAVE_ARCH_KASAN if MMU && 64BIT
110 select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
111 select HAVE_ARCH_KFENCE if MMU && 64BIT
112 select HAVE_ARCH_KGDB if !XIP_KERNEL
113 select HAVE_ARCH_KGDB_QXFER_PKT
114 select HAVE_ARCH_MMAP_RND_BITS if MMU
115 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
116 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
117 select HAVE_ARCH_SECCOMP_FILTER
118 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
119 select HAVE_ARCH_TRACEHOOK
120 select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
121 select HAVE_ARCH_USERFAULTFD_MINOR if 64BIT && USERFAULTFD
122 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT
123 select HAVE_ASM_MODVERSIONS
124 select HAVE_CONTEXT_TRACKING_USER
125 select HAVE_DEBUG_KMEMLEAK
126 select HAVE_DMA_CONTIGUOUS if MMU
127 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
128 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
129 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
130 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
131 select HAVE_FUNCTION_GRAPH_TRACER
132 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
133 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
134 select HAVE_EBPF_JIT if MMU
135 select HAVE_FAST_GUP if MMU
136 select HAVE_FUNCTION_ARG_ACCESS_API
137 select HAVE_FUNCTION_ERROR_INJECTION
138 select HAVE_GCC_PLUGINS
139 select HAVE_GENERIC_VDSO if MMU && 64BIT
140 select HAVE_IRQ_TIME_ACCOUNTING
141 select HAVE_KPROBES if !XIP_KERNEL
142 select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
143 select HAVE_KRETPROBES if !XIP_KERNEL
144 # https://github.com/ClangBuiltLinux/linux/issues/1881
145 select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD
149 select HAVE_PERF_EVENTS
150 select HAVE_PERF_REGS
151 select HAVE_PERF_USER_STACK_DUMP
152 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
153 select HAVE_PREEMPT_DYNAMIC_KEY if !XIP_KERNEL
154 select HAVE_REGS_AND_STACK_ACCESS_API
155 select HAVE_RETHOOK if !XIP_KERNEL
157 select HAVE_SAMPLE_FTRACE_DIRECT
158 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
159 select HAVE_STACKPROTECTOR
160 select HAVE_SYSCALL_TRACEPOINTS
161 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
163 select IRQ_FORCED_THREADING
164 select KASAN_VMALLOC if KASAN
165 select LOCK_MM_AND_FIND_VMA
166 select MMU_GATHER_RCU_TABLE_FREE if SMP && MMU
167 select MODULES_USE_ELF_RELA if MODULES
168 select MODULE_SECTIONS if MODULES
170 select OF_EARLY_FLATTREE
172 select PCI_DOMAINS_GENERIC if PCI
173 select PCI_MSI if PCI
174 select RISCV_ALTERNATIVE if !XIP_KERNEL
176 select RISCV_TIMER if RISCV_SBI
179 select SYSCTL_EXCEPTION_TRACE
180 select THREAD_INFO_IN_TASK
181 select TRACE_IRQFLAGS_SUPPORT
182 select UACCESS_MEMCPY if !MMU
183 select ZONE_DMA32 if 64BIT
185 config CLANG_SUPPORTS_DYNAMIC_FTRACE
187 # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e
188 depends on CLANG_VERSION >= 130000
189 # https://github.com/ClangBuiltLinux/linux/issues/1817
190 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
192 config GCC_SUPPORTS_DYNAMIC_FTRACE
194 depends on $(cc-option,-fpatchable-function-entry=8)
196 config HAVE_SHADOW_CALL_STACK
197 def_bool $(cc-option,-fsanitize=shadow-call-stack)
198 # https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/a484e843e6eeb51f0cb7b8819e50da6d2444d769
199 depends on $(ld-option,--no-relax-gp)
201 config RISCV_USE_LINKER_RELAXATION
203 # https://github.com/llvm/llvm-project/commit/6611d58f5bbcbec77262d392e2923e1d680f6985
204 depends on !LD_IS_LLD || LLD_VERSION >= 150000
206 # https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6
207 config ARCH_HAS_BROKEN_DWARF5
209 depends on RISCV_USE_LINKER_RELAXATION
210 # https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a
211 depends on AS_IS_LLVM && AS_VERSION < 180000
212 # https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77
213 depends on LD_IS_LLD && LLD_VERSION < 180000
215 config ARCH_MMAP_RND_BITS_MIN
219 config ARCH_MMAP_RND_COMPAT_BITS_MIN
222 # max bits determined by the following formula:
223 # VA_BITS - PAGE_SHIFT - 3
224 config ARCH_MMAP_RND_BITS_MAX
225 default 24 if 64BIT # SV39 based
228 config ARCH_MMAP_RND_COMPAT_BITS_MAX
231 # set if we run in machine mode, cleared if we run in supervisor mode
236 # set if we are running in S-mode and can use SBI calls
239 depends on !RISCV_M_MODE
243 bool "MMU-based Paged Memory Management Support"
246 Select if you want MMU-based virtualised addressing space
247 support by paged memory management. If unsure, say 'Y'.
251 default 0xC0000000 if 32BIT && MMU
252 default 0x80000000 if !MMU
253 default 0xff60000000000000 if 64BIT
255 config KASAN_SHADOW_OFFSET
257 depends on KASAN_GENERIC
258 default 0xdfffffff00000000 if 64BIT
259 default 0xffffffff if 32BIT
261 config ARCH_FLATMEM_ENABLE
264 config ARCH_SPARSEMEM_ENABLE
267 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
268 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
270 config ARCH_SELECT_MEMORY_MODEL
271 def_bool ARCH_SPARSEMEM_ENABLE
273 config ARCH_SUPPORTS_UPROBES
276 config STACKTRACE_SUPPORT
282 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
284 config GENERIC_BUG_RELATIVE_POINTERS
287 config GENERIC_CALIBRATE_DELAY
293 config GENERIC_HWEIGHT
296 config FIX_EARLYCON_MEM
299 config PGTABLE_LEVELS
304 config LOCKDEP_SUPPORT
307 config RISCV_DMA_NONCOHERENT
309 select ARCH_HAS_DMA_PREP_COHERENT
310 select ARCH_HAS_SETUP_DMA_OPS
311 select ARCH_HAS_SYNC_DMA_FOR_CPU
312 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
313 select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB
315 config RISCV_NONSTANDARD_CACHE_OPS
318 This enables function pointer support for non-standard noncoherent
319 systems to handle cache management.
322 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
324 config AS_HAS_OPTION_ARCH
325 # https://reviews.llvm.org/D123515
327 depends on $(as-instr, .option arch$(comma) +m)
329 source "arch/riscv/Kconfig.socs"
330 source "arch/riscv/Kconfig.errata"
335 bool "Allow configurations that result in non-portable kernels"
337 RISC-V kernel binaries are compatible between all known systems
338 whenever possible, but there are some use cases that can only be
339 satisfied by configurations that result in kernel binaries that are
340 not portable between systems.
342 Selecting N does not guarantee kernels will be portable to all known
343 systems. Selecting any of the options guarded by NONPORTABLE will
344 result in kernel binaries that are unlikely to be portable between
353 This selects the base ISA that this kernel will target and must match
358 depends on NONPORTABLE
360 select GENERIC_LIB_ASHLDI3
361 select GENERIC_LIB_ASHRDI3
362 select GENERIC_LIB_LSHRDI3
363 select GENERIC_LIB_UCMPDI2
368 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
369 select SWIOTLB if MMU
373 # We must be able to map all physical memory into the kernel, but the compiler
374 # is still a bit more efficient when generating code if it's setup in a manner
375 # such that it can only map 2GiB of memory.
377 prompt "Kernel Code Model"
378 default CMODEL_MEDLOW if 32BIT
379 default CMODEL_MEDANY if 64BIT
382 bool "medium low code model"
384 bool "medium any code model"
387 config MODULE_SECTIONS
389 select HAVE_MOD_ARCH_SPECIFIC
392 bool "Symmetric Multi-Processing"
394 This enables support for systems with more than one CPU. If
395 you say N here, the kernel will run on single and
396 multiprocessor machines, but will use only one CPU of a
397 multiprocessor machine. If you say Y here, the kernel will run
398 on many, but not all, single processor machines. On a single
399 processor machine, the kernel will run faster if you say N
402 If you don't know what to do here, say N.
405 bool "Multi-core scheduler support"
408 Multi-core scheduler support improves the CPU scheduler's decision
409 making when dealing with multi-core CPU chips at a cost of slightly
410 increased overhead in some places. If unsure say N here.
413 int "Maximum number of CPUs (2-512)"
415 range 2 512 if !RISCV_SBI_V01
416 range 2 32 if RISCV_SBI_V01 && 32BIT
417 range 2 64 if RISCV_SBI_V01 && 64BIT
418 default "32" if 32BIT
419 default "64" if 64BIT
422 bool "Support for hot-pluggable CPUs"
424 select GENERIC_IRQ_MIGRATION
427 Say Y here to experiment with turning CPUs off and on. CPUs
428 can be controlled through /sys/devices/system/cpu.
430 Say N if you want to disable CPU hotplug.
441 # Common NUMA Features
443 bool "NUMA Memory Allocation and Scheduler Support"
444 depends on SMP && MMU
445 select ARCH_SUPPORTS_NUMA_BALANCING
446 select GENERIC_ARCH_NUMA
447 select HAVE_SETUP_PER_CPU_AREA
448 select NEED_PER_CPU_EMBED_FIRST_CHUNK
449 select NEED_PER_CPU_PAGE_FIRST_CHUNK
451 select USE_PERCPU_NUMA_NODE_ID
453 Enable NUMA (Non-Uniform Memory Access) support.
455 The kernel will try to allocate memory used by a CPU on the
456 local memory of the CPU and add some more NUMA awareness to the kernel.
459 int "Maximum NUMA Nodes (as a power of 2)"
464 Specify the maximum number of NUMA Nodes available on the target
465 system. Increases memory reserved to accommodate various tables.
467 config RISCV_ALTERNATIVE
469 depends on !XIP_KERNEL
471 This Kconfig allows the kernel to automatically patch the
472 erratum or cpufeature required by the execution platform at run
473 time. The code patching overhead is minimal, as it's only done
474 once at boot and once on each module load.
476 config RISCV_ALTERNATIVE_EARLY
478 depends on RISCV_ALTERNATIVE
480 Allows early patching of the kernel for special errata
483 bool "Emit compressed instructions when building Linux"
486 Adds "C" to the ISA subsets that the toolchain is allowed to emit
487 when building Linux, which results in compressed instructions in the
490 If you don't know what to do here, say Y.
492 config RISCV_ISA_SVNAPOT
493 bool "Svnapot extension support for supervisor mode NAPOT pages"
494 depends on 64BIT && MMU
495 depends on RISCV_ALTERNATIVE
498 Allow kernel to detect the Svnapot ISA-extension dynamically at boot
499 time and enable its usage.
501 The Svnapot extension is used to mark contiguous PTEs as a range
502 of contiguous virtual-to-physical translations for a naturally
503 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
504 size. When HUGETLBFS is also selected this option unconditionally
505 allocates some memory for each NAPOT page size supported by the kernel.
506 When optimizing for low memory consumption and for platforms without
507 the Svnapot extension, it may be better to say N here.
509 If you don't know what to do here, say Y.
511 config RISCV_ISA_SVPBMT
512 bool "Svpbmt extension support for supervisor mode page-based memory types"
513 depends on 64BIT && MMU
514 depends on RISCV_ALTERNATIVE
517 Adds support to dynamically detect the presence of the Svpbmt
518 ISA-extension (Supervisor-mode: page-based memory types) and
521 The memory type for a page contains a combination of attributes
522 that indicate the cacheability, idempotency, and ordering
523 properties for access to that page.
525 The Svpbmt extension is only available on 64-bit cpus.
527 If you don't know what to do here, say Y.
529 config TOOLCHAIN_HAS_V
532 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
533 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
534 depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
535 depends on AS_HAS_OPTION_ARCH
538 bool "VECTOR extension support"
539 depends on TOOLCHAIN_HAS_V
541 select DYNAMIC_SIGFRAME
544 Say N here if you want to disable all vector related procedure
547 If you don't know what to do here, say Y.
549 config RISCV_ISA_V_DEFAULT_ENABLE
550 bool "Enable userspace Vector by default"
551 depends on RISCV_ISA_V
554 Say Y here if you want to enable Vector in userspace by default.
555 Otherwise, userspace has to make explicit prctl() call to enable
556 Vector, or enable it via the sysctl interface.
558 If you don't know what to do here, say Y.
560 config RISCV_ISA_V_UCOPY_THRESHOLD
561 int "Threshold size for vectorized user copies"
562 depends on RISCV_ISA_V
565 Prefer using vectorized copy_to_user()/copy_from_user() when the
566 workload size exceeds this value.
568 config RISCV_ISA_V_PREEMPTIVE
569 bool "Run kernel-mode Vector with kernel preemption"
570 depends on PREEMPTION
571 depends on RISCV_ISA_V
574 Usually, in-kernel SIMD routines are run with preemption disabled.
575 Functions which envoke long running SIMD thus must yield core's
576 vector unit to prevent blocking other tasks for too long.
578 This config allows kernel to run SIMD without explicitly disable
579 preemption. Enabling this config will result in higher memory
580 consumption due to the allocation of per-task's kernel Vector context.
582 config TOOLCHAIN_HAS_ZBB
585 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
586 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
587 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
588 depends on AS_HAS_OPTION_ARCH
590 # This symbol indicates that the toolchain supports all v1.0 vector crypto
591 # extensions, including Zvk*, Zvbb, and Zvbc. LLVM added all of these at once.
592 # binutils added all except Zvkb, then added Zvkb. So we just check for Zvkb.
593 config TOOLCHAIN_HAS_VECTOR_CRYPTO
594 def_bool $(as-instr, .option arch$(comma) +v$(comma) +zvkb)
595 depends on AS_HAS_OPTION_ARCH
598 bool "Zbb extension support for bit manipulation instructions"
599 depends on TOOLCHAIN_HAS_ZBB
601 depends on RISCV_ALTERNATIVE
604 Adds support to dynamically detect the presence of the ZBB
605 extension (basic bit manipulation) and enable its usage.
607 The Zbb extension provides instructions to accelerate a number
608 of bit-specific operations (count bit population, sign extending,
611 If you don't know what to do here, say Y.
613 config RISCV_ISA_ZICBOM
614 bool "Zicbom extension support for non-coherent DMA operation"
616 depends on RISCV_ALTERNATIVE
618 select RISCV_DMA_NONCOHERENT
619 select DMA_DIRECT_REMAP
621 Adds support to dynamically detect the presence of the ZICBOM
622 extension (Cache Block Management Operations) and enable its
625 The Zicbom extension can be used to handle for example
626 non-coherent DMA support on devices that need it.
628 If you don't know what to do here, say Y.
630 config RISCV_ISA_ZICBOZ
631 bool "Zicboz extension support for faster zeroing of memory"
633 depends on RISCV_ALTERNATIVE
636 Enable the use of the Zicboz extension (cbo.zero instruction)
639 The Zicboz extension is used for faster zeroing of memory.
641 If you don't know what to do here, say Y.
643 config TOOLCHAIN_HAS_ZIHINTPAUSE
646 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
647 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
648 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
650 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
652 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
653 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd
654 depends on AS_IS_GNU && AS_VERSION >= 23600
656 Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer
657 20191213 version, which moves some instructions from the I extension to
658 the Zicsr and Zifencei extensions. This requires explicitly specifying
659 Zicsr and Zifencei when binutils >= 2.38 or GCC >= 12.1.0. Zicsr
660 and Zifencei are supported in binutils from version 2.36 onwards.
661 To make life easier, and avoid forcing toolchains that default to a
662 newer ISA spec to version 2.2, relax the check to binutils >= 2.36.
663 For clang < 17 or GCC < 11.3.0, for which this is not possible or need
664 special treatment, this is dealt with in TOOLCHAIN_NEEDS_OLD_ISA_SPEC.
666 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
668 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
669 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
670 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d29f5d6ab513c52fd872f532c492e35ae9fd6671
671 depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC && GCC_VERSION < 110300)
673 Certain versions of clang and GCC do not support zicsr and zifencei via
674 -march. This option causes an older ISA spec compatible with these older
675 versions of clang and GCC to be passed to GAS, which has the same result
676 as passing zicsr and zifencei to -march.
682 Say N here if you want to disable all floating-point related procedure
685 If you don't know what to do here, say Y.
688 bool "Independent irq & softirq stacks" if EXPERT
690 select HAVE_IRQ_EXIT_ON_IRQ_STACK
691 select HAVE_SOFTIRQ_ON_OWN_STACK
693 Add independent irq & softirq stacks for percpu to prevent kernel stack
694 overflows. We may save some memory footprint by disabling IRQ_STACKS.
696 config THREAD_SIZE_ORDER
697 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
699 default 1 if 32BIT && !KASAN
700 default 3 if 64BIT && KASAN
703 Specify the Pages of thread stack size (from 4KB to 64KB), which also
704 affects irq stack size, which is equal to thread stack size.
706 config RISCV_MISALIGNED
708 select SYSCTL_ARCH_UNALIGN_ALLOW
710 Embed support for emulating misaligned loads and stores.
713 prompt "Unaligned Accesses Support"
714 default RISCV_PROBE_UNALIGNED_ACCESS
716 This determines the level of support for unaligned accesses. This
717 information is used by the kernel to perform optimizations. It is also
718 exposed to user space via the hwprobe syscall. The hardware will be
719 probed at boot by default.
721 config RISCV_PROBE_UNALIGNED_ACCESS
722 bool "Probe for hardware unaligned access support"
723 select RISCV_MISALIGNED
725 During boot, the kernel will run a series of tests to determine the
726 speed of unaligned accesses. This probing will dynamically determine
727 the speed of unaligned accesses on the underlying system. If unaligned
728 memory accesses trap into the kernel as they are not supported by the
729 system, the kernel will emulate the unaligned accesses to preserve the
732 config RISCV_EMULATED_UNALIGNED_ACCESS
733 bool "Emulate unaligned access where system support is missing"
734 select RISCV_MISALIGNED
736 If unaligned memory accesses trap into the kernel as they are not
737 supported by the system, the kernel will emulate the unaligned
738 accesses to preserve the UABI. When the underlying system does support
739 unaligned accesses, the unaligned accesses are assumed to be slow.
741 config RISCV_SLOW_UNALIGNED_ACCESS
742 bool "Assume the system supports slow unaligned memory accesses"
743 depends on NONPORTABLE
745 Assume that the system supports slow unaligned memory accesses. The
746 kernel and userspace programs may not be able to run at all on systems
747 that do not support unaligned memory accesses.
749 config RISCV_EFFICIENT_UNALIGNED_ACCESS
750 bool "Assume the system supports fast unaligned memory accesses"
751 depends on NONPORTABLE
752 select DCACHE_WORD_ACCESS if MMU
753 select HAVE_EFFICIENT_UNALIGNED_ACCESS
755 Assume that the system supports fast unaligned memory accesses. When
756 enabled, this option improves the performance of the kernel on such
757 systems. However, the kernel and userspace programs will run much more
758 slowly, or will not be able to run at all, on systems that do not
759 support efficient unaligned memory accesses.
763 endmenu # "Platform type"
765 menu "Kernel features"
767 source "kernel/Kconfig.hz"
770 bool "SBI v0.1 support"
773 This config allows kernel to use SBI v0.1 APIs. This will be
774 deprecated in future once legacy M-mode software are no longer in use.
776 config RISCV_BOOT_SPINWAIT
777 bool "Spinwait booting method"
779 default y if RISCV_SBI_V01 || RISCV_M_MODE
781 This enables support for booting Linux via spinwait method. In the
782 spinwait method, all cores randomly jump to Linux. One of the cores
783 gets chosen via lottery and all other keep spinning on a percpu
784 variable. This method cannot support CPU hotplug and sparse hartid
785 scheme. It should be only enabled for M-mode Linux or platforms relying
786 on older firmware without SBI HSM extension. All other platforms should
787 rely on ordered booting via SBI HSM extension which gets chosen
788 dynamically at runtime if the firmware supports it.
790 Since spinwait is incompatible with sparse hart IDs, it requires
791 NR_CPUS be large enough to contain the physical hart ID of the first
794 If unsure what to do here, say N.
796 config ARCH_SUPPORTS_KEXEC
799 config ARCH_SELECTS_KEXEC
802 select HOTPLUG_CPU if SMP
804 config ARCH_SUPPORTS_KEXEC_FILE
807 config ARCH_SELECTS_KEXEC_FILE
809 depends on KEXEC_FILE
810 select HAVE_IMA_KEXEC if IMA
813 config ARCH_SUPPORTS_KEXEC_PURGATORY
814 def_bool ARCH_SUPPORTS_KEXEC_FILE
816 config ARCH_SUPPORTS_CRASH_DUMP
819 config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
823 bool "Kernel support for 32-bit U-mode"
825 depends on 64BIT && MMU
827 This option enables support for a 32-bit U-mode running under a 64-bit
828 kernel at S-mode. riscv32-specific components such as system calls,
829 the user helper functions (vdso), signal rt_frame functions and the
830 ptrace interface are handled appropriately by the kernel.
832 If you want to execute 32-bit userspace applications, say Y.
835 bool "Enable paravirtualization code"
838 This changes the kernel so it can modify itself when it is run
839 under a hypervisor, potentially improving performance significantly
840 over full virtualization.
842 config PARAVIRT_TIME_ACCOUNTING
843 bool "Paravirtual steal time accounting"
846 Select this option to enable fine granularity task steal time
847 accounting. Time spent executing other tasks in parallel with
848 the current vCPU is discounted from the vCPU power. To account for
849 that, there can be a small performance impact.
851 If in doubt, say N here.
854 bool "Build a relocatable kernel"
855 depends on MMU && 64BIT && !XIP_KERNEL
857 This builds a kernel as a Position Independent Executable (PIE),
858 which retains all relocation metadata required to relocate the
859 kernel binary at runtime to a different virtual address than the
860 address it was linked at.
861 Since RISCV uses the RELA relocation format, this requires a
862 relocation pass at runtime even if the kernel is loaded at the
863 same address it was linked at.
867 config RANDOMIZE_BASE
868 bool "Randomize the address of the kernel image"
870 depends on MMU && 64BIT && !XIP_KERNEL
872 Randomizes the virtual address at which the kernel image is
873 loaded, as a security feature that deters exploit attempts
874 relying on knowledge of the location of kernel internals.
876 It is the bootloader's job to provide entropy, by passing a
877 random u64 value in /chosen/kaslr-seed at kernel entry.
879 When booting via the UEFI stub, it will invoke the firmware's
880 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
881 to the kernel proper. In addition, it will randomise the physical
882 location of the kernel Image as well.
886 endmenu # "Kernel features"
891 string "Built-in kernel command line"
893 For most platforms, the arguments for the kernel's command line
894 are provided at run-time, during boot. However, there are cases
895 where either no arguments are being provided or the provided
896 arguments are insufficient or even invalid.
898 When that occurs, it is possible to define a built-in command
899 line here and choose how the kernel should use it later on.
902 prompt "Built-in command line usage" if CMDLINE != ""
903 default CMDLINE_FALLBACK
905 Choose how the kernel will handle the provided built-in command
908 config CMDLINE_FALLBACK
909 bool "Use bootloader kernel arguments if available"
911 Use the built-in command line as fallback in case we get nothing
912 during boot. This is the default behaviour.
914 config CMDLINE_EXTEND
915 bool "Extend bootloader kernel arguments"
917 The command-line arguments provided during boot will be
918 appended to the built-in command line. This is useful in
919 cases where the provided arguments are insufficient and
920 you don't want to or cannot modify them.
923 bool "Always use the default kernel command string"
925 Always use the built-in command line, even if we get one during
926 boot. This is useful in case you need to override the provided
927 command line on systems where you don't have or want control
936 bool "UEFI runtime support"
937 depends on OF && !XIP_KERNEL
940 select ARCH_SUPPORTS_ACPI if 64BIT
941 select EFI_GENERIC_STUB
942 select EFI_PARAMS_FROM_FDT
943 select EFI_RUNTIME_WRAPPERS
949 This option provides support for runtime services provided
950 by UEFI firmware (such as non-volatile variables, realtime
951 clock, and platform reset). A UEFI stub is also provided to
952 allow the kernel to be booted as an EFI application. This
953 is only useful on systems that have UEFI firmware.
955 config CC_HAVE_STACKPROTECTOR_TLS
956 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
958 config STACKPROTECTOR_PER_TASK
960 depends on !RANDSTRUCT
961 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
963 config PHYS_RAM_BASE_FIXED
964 bool "Explicitly specified physical RAM address"
965 depends on NONPORTABLE
969 hex "Platform Physical RAM address"
970 depends on PHYS_RAM_BASE_FIXED
973 This is the physical address of RAM in the system. It has to be
974 explicitly specified to run early relocations of read-write data
978 bool "Kernel Execute-In-Place from ROM"
979 depends on MMU && SPARSEMEM && NONPORTABLE
980 # This prevents XIP from being enabled by all{yes,mod}config, which
981 # fail to build since XIP doesn't support large kernels.
982 depends on !COMPILE_TEST
983 select PHYS_RAM_BASE_FIXED
985 Execute-In-Place allows the kernel to run from non-volatile storage
986 directly addressable by the CPU, such as NOR flash. This saves RAM
987 space since the text section of the kernel is not loaded from flash
988 to RAM. Read-write sections, such as the data section and stack,
989 are still copied to RAM. The XIP kernel is not compressed since
990 it has to run directly from flash, so it will take more space to
991 store it. The flash address used to link the kernel object files,
992 and for storing it, is configuration dependent. Therefore, if you
993 say Y here, you must know the proper physical address where to
994 store the kernel image depending on your own flash memory usage.
996 Also note that the make target becomes "make xipImage" rather than
997 "make zImage" or "make Image". The final kernel binary to put in
998 ROM memory will be arch/riscv/boot/xipImage.
1000 SPARSEMEM is required because the kernel text and rodata that are
1001 flash resident are not backed by memmap, then any attempt to get
1002 a struct page on those regions will trigger a fault.
1006 config XIP_PHYS_ADDR
1007 hex "XIP Kernel Physical Location"
1008 depends on XIP_KERNEL
1009 default "0x21000000"
1011 This is the physical address in your flash memory the kernel will
1012 be linked for and stored to. This address is dependent on your
1015 config RISCV_ISA_FALLBACK
1016 bool "Permit falling back to parsing riscv,isa for extension support by default"
1019 Parsing the "riscv,isa" devicetree property has been deprecated and
1020 replaced by a list of explicitly defined strings. For compatibility
1021 with existing platforms, the kernel will fall back to parsing the
1022 "riscv,isa" property if the replacements are not found.
1024 Selecting N here will result in a kernel that does not use the
1025 fallback, unless the commandline "riscv_isa_fallback" parameter is
1028 Please see the dt-binding, located at
1029 Documentation/devicetree/bindings/riscv/extensions.yaml for details
1030 on the replacement properties, "riscv,isa-base" and
1031 "riscv,isa-extensions".
1034 bool "Built-in device tree"
1035 depends on OF && NONPORTABLE
1036 default y if XIP_KERNEL
1038 endmenu # "Boot options"
1042 default !NONPORTABLE
1047 config ARCH_PROC_KCORE_TEXT
1050 menu "Power management options"
1052 source "kernel/power/Kconfig"
1054 config ARCH_HIBERNATION_POSSIBLE
1057 config ARCH_HIBERNATION_HEADER
1058 def_bool HIBERNATION
1060 config ARCH_SUSPEND_POSSIBLE
1063 endmenu # "Power management options"
1065 menu "CPU Power Management"
1067 source "drivers/cpuidle/Kconfig"
1069 source "drivers/cpufreq/Kconfig"
1071 endmenu # "CPU Power Management"
1073 source "arch/riscv/kvm/Kconfig"
1075 source "drivers/acpi/Kconfig"