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
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 RISCV_M_MODE
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
148 select HAVE_PAGE_SIZE_4KB
150 select HAVE_PERF_EVENTS
151 select HAVE_PERF_REGS
152 select HAVE_PERF_USER_STACK_DUMP
153 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
154 select HAVE_PREEMPT_DYNAMIC_KEY if !XIP_KERNEL
155 select HAVE_REGS_AND_STACK_ACCESS_API
156 select HAVE_RETHOOK if !XIP_KERNEL
158 select HAVE_RUST if 64BIT
159 select HAVE_SAMPLE_FTRACE_DIRECT
160 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
161 select HAVE_STACKPROTECTOR
162 select HAVE_SYSCALL_TRACEPOINTS
163 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
165 select IRQ_FORCED_THREADING
166 select KASAN_VMALLOC if KASAN
167 select LOCK_MM_AND_FIND_VMA
168 select MMU_GATHER_RCU_TABLE_FREE if SMP && MMU
169 select MODULES_USE_ELF_RELA if MODULES
170 select MODULE_SECTIONS if MODULES
172 select OF_EARLY_FLATTREE
174 select PCI_DOMAINS_GENERIC if PCI
175 select PCI_MSI if PCI
176 select RISCV_ALTERNATIVE if !XIP_KERNEL
178 select RISCV_TIMER if RISCV_SBI
181 select SYSCTL_EXCEPTION_TRACE
182 select THREAD_INFO_IN_TASK
183 select TRACE_IRQFLAGS_SUPPORT
184 select UACCESS_MEMCPY if !MMU
185 select ZONE_DMA32 if 64BIT
187 config CLANG_SUPPORTS_DYNAMIC_FTRACE
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
233 bool "Build a kernel that runs in machine mode"
237 Select this option if you want to run the kernel in M-mode,
238 without the assistance of any other firmware.
240 # set if we are running in S-mode and can use SBI calls
243 depends on !RISCV_M_MODE
247 bool "MMU-based Paged Memory Management Support"
250 Select if you want MMU-based virtualised addressing space
251 support by paged memory management. If unsure, say 'Y'.
255 default 0x80000000 if !MMU && RISCV_M_MODE
256 default 0x80200000 if !MMU
257 default 0xc0000000 if 32BIT
258 default 0xff60000000000000 if 64BIT
260 config KASAN_SHADOW_OFFSET
262 depends on KASAN_GENERIC
263 default 0xdfffffff00000000 if 64BIT
264 default 0xffffffff if 32BIT
266 config ARCH_FLATMEM_ENABLE
269 config ARCH_SPARSEMEM_ENABLE
272 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
273 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
275 config ARCH_SELECT_MEMORY_MODEL
276 def_bool ARCH_SPARSEMEM_ENABLE
278 config ARCH_SUPPORTS_UPROBES
281 config STACKTRACE_SUPPORT
287 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
289 config GENERIC_BUG_RELATIVE_POINTERS
292 config GENERIC_CALIBRATE_DELAY
298 config GENERIC_HWEIGHT
301 config FIX_EARLYCON_MEM
304 config PGTABLE_LEVELS
309 config LOCKDEP_SUPPORT
312 config RISCV_DMA_NONCOHERENT
314 select ARCH_HAS_DMA_PREP_COHERENT
315 select ARCH_HAS_SETUP_DMA_OPS
316 select ARCH_HAS_SYNC_DMA_FOR_CPU
317 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
318 select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB
320 config RISCV_NONSTANDARD_CACHE_OPS
323 This enables function pointer support for non-standard noncoherent
324 systems to handle cache management.
327 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
329 config AS_HAS_OPTION_ARCH
330 # https://github.com/llvm/llvm-project/commit/9e8ed3403c191ab9c4903e8eeb8f732ff8a43cb4
332 depends on $(as-instr, .option arch$(comma) +m)
334 source "arch/riscv/Kconfig.socs"
335 source "arch/riscv/Kconfig.errata"
340 bool "Allow configurations that result in non-portable kernels"
342 RISC-V kernel binaries are compatible between all known systems
343 whenever possible, but there are some use cases that can only be
344 satisfied by configurations that result in kernel binaries that are
345 not portable between systems.
347 Selecting N does not guarantee kernels will be portable to all known
348 systems. Selecting any of the options guarded by NONPORTABLE will
349 result in kernel binaries that are unlikely to be portable between
358 This selects the base ISA that this kernel will target and must match
363 depends on NONPORTABLE
365 select GENERIC_LIB_ASHLDI3
366 select GENERIC_LIB_ASHRDI3
367 select GENERIC_LIB_LSHRDI3
368 select GENERIC_LIB_UCMPDI2
373 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
374 select SWIOTLB if MMU
378 # We must be able to map all physical memory into the kernel, but the compiler
379 # is still a bit more efficient when generating code if it's setup in a manner
380 # such that it can only map 2GiB of memory.
382 prompt "Kernel Code Model"
383 default CMODEL_MEDLOW if 32BIT
384 default CMODEL_MEDANY if 64BIT
387 bool "medium low code model"
389 bool "medium any code model"
392 config MODULE_SECTIONS
394 select HAVE_MOD_ARCH_SPECIFIC
397 bool "Symmetric Multi-Processing"
399 This enables support for systems with more than one CPU. If
400 you say N here, the kernel will run on single and
401 multiprocessor machines, but will use only one CPU of a
402 multiprocessor machine. If you say Y here, the kernel will run
403 on many, but not all, single processor machines. On a single
404 processor machine, the kernel will run faster if you say N
407 If you don't know what to do here, say N.
410 bool "Multi-core scheduler support"
413 Multi-core scheduler support improves the CPU scheduler's decision
414 making when dealing with multi-core CPU chips at a cost of slightly
415 increased overhead in some places. If unsure say N here.
418 int "Maximum number of CPUs (2-512)"
420 range 2 512 if !RISCV_SBI_V01
421 range 2 32 if RISCV_SBI_V01 && 32BIT
422 range 2 64 if RISCV_SBI_V01 && 64BIT
423 default "32" if 32BIT
424 default "64" if 64BIT
427 bool "Support for hot-pluggable CPUs"
429 select GENERIC_IRQ_MIGRATION
432 Say Y here to experiment with turning CPUs off and on. CPUs
433 can be controlled through /sys/devices/system/cpu.
435 Say N if you want to disable CPU hotplug.
446 # Common NUMA Features
448 bool "NUMA Memory Allocation and Scheduler Support"
449 depends on SMP && MMU
450 select ARCH_SUPPORTS_NUMA_BALANCING
451 select GENERIC_ARCH_NUMA
452 select HAVE_SETUP_PER_CPU_AREA
453 select NEED_PER_CPU_EMBED_FIRST_CHUNK
454 select NEED_PER_CPU_PAGE_FIRST_CHUNK
456 select USE_PERCPU_NUMA_NODE_ID
458 Enable NUMA (Non-Uniform Memory Access) support.
460 The kernel will try to allocate memory used by a CPU on the
461 local memory of the CPU and add some more NUMA awareness to the kernel.
464 int "Maximum NUMA Nodes (as a power of 2)"
469 Specify the maximum number of NUMA Nodes available on the target
470 system. Increases memory reserved to accommodate various tables.
472 config RISCV_ALTERNATIVE
474 depends on !XIP_KERNEL
476 This Kconfig allows the kernel to automatically patch the
477 erratum or cpufeature required by the execution platform at run
478 time. The code patching overhead is minimal, as it's only done
479 once at boot and once on each module load.
481 config RISCV_ALTERNATIVE_EARLY
483 depends on RISCV_ALTERNATIVE
485 Allows early patching of the kernel for special errata
488 bool "Emit compressed instructions when building Linux"
491 Adds "C" to the ISA subsets that the toolchain is allowed to emit
492 when building Linux, which results in compressed instructions in the
495 If you don't know what to do here, say Y.
497 config RISCV_ISA_SVNAPOT
498 bool "Svnapot extension support for supervisor mode NAPOT pages"
499 depends on 64BIT && MMU
500 depends on RISCV_ALTERNATIVE
503 Allow kernel to detect the Svnapot ISA-extension dynamically at boot
504 time and enable its usage.
506 The Svnapot extension is used to mark contiguous PTEs as a range
507 of contiguous virtual-to-physical translations for a naturally
508 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
509 size. When HUGETLBFS is also selected this option unconditionally
510 allocates some memory for each NAPOT page size supported by the kernel.
511 When optimizing for low memory consumption and for platforms without
512 the Svnapot extension, it may be better to say N here.
514 If you don't know what to do here, say Y.
516 config RISCV_ISA_SVPBMT
517 bool "Svpbmt extension support for supervisor mode page-based memory types"
518 depends on 64BIT && MMU
519 depends on RISCV_ALTERNATIVE
522 Adds support to dynamically detect the presence of the Svpbmt
523 ISA-extension (Supervisor-mode: page-based memory types) and
526 The memory type for a page contains a combination of attributes
527 that indicate the cacheability, idempotency, and ordering
528 properties for access to that page.
530 The Svpbmt extension is only available on 64-bit cpus.
532 If you don't know what to do here, say Y.
534 config TOOLCHAIN_HAS_V
537 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
538 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
539 depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
540 depends on AS_HAS_OPTION_ARCH
543 bool "VECTOR extension support"
544 depends on TOOLCHAIN_HAS_V
546 select DYNAMIC_SIGFRAME
549 Say N here if you want to disable all vector related procedure
552 If you don't know what to do here, say Y.
554 config RISCV_ISA_V_DEFAULT_ENABLE
555 bool "Enable userspace Vector by default"
556 depends on RISCV_ISA_V
559 Say Y here if you want to enable Vector in userspace by default.
560 Otherwise, userspace has to make explicit prctl() call to enable
561 Vector, or enable it via the sysctl interface.
563 If you don't know what to do here, say Y.
565 config RISCV_ISA_V_UCOPY_THRESHOLD
566 int "Threshold size for vectorized user copies"
567 depends on RISCV_ISA_V
570 Prefer using vectorized copy_to_user()/copy_from_user() when the
571 workload size exceeds this value.
573 config RISCV_ISA_V_PREEMPTIVE
574 bool "Run kernel-mode Vector with kernel preemption"
575 depends on PREEMPTION
576 depends on RISCV_ISA_V
579 Usually, in-kernel SIMD routines are run with preemption disabled.
580 Functions which envoke long running SIMD thus must yield core's
581 vector unit to prevent blocking other tasks for too long.
583 This config allows kernel to run SIMD without explicitly disable
584 preemption. Enabling this config will result in higher memory
585 consumption due to the allocation of per-task's kernel Vector context.
587 config TOOLCHAIN_HAS_ZBB
590 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
591 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
592 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
593 depends on AS_HAS_OPTION_ARCH
595 # This symbol indicates that the toolchain supports all v1.0 vector crypto
596 # extensions, including Zvk*, Zvbb, and Zvbc. LLVM added all of these at once.
597 # binutils added all except Zvkb, then added Zvkb. So we just check for Zvkb.
598 config TOOLCHAIN_HAS_VECTOR_CRYPTO
599 def_bool $(as-instr, .option arch$(comma) +v$(comma) +zvkb)
600 depends on AS_HAS_OPTION_ARCH
603 bool "Zbb extension support for bit manipulation instructions"
604 depends on TOOLCHAIN_HAS_ZBB
605 depends on RISCV_ALTERNATIVE
608 Adds support to dynamically detect the presence of the ZBB
609 extension (basic bit manipulation) and enable its usage.
611 The Zbb extension provides instructions to accelerate a number
612 of bit-specific operations (count bit population, sign extending,
615 If you don't know what to do here, say Y.
617 config RISCV_ISA_ZICBOM
618 bool "Zicbom extension support for non-coherent DMA operation"
620 depends on RISCV_ALTERNATIVE
622 select RISCV_DMA_NONCOHERENT
623 select DMA_DIRECT_REMAP
625 Adds support to dynamically detect the presence of the ZICBOM
626 extension (Cache Block Management Operations) and enable its
629 The Zicbom extension can be used to handle for example
630 non-coherent DMA support on devices that need it.
632 If you don't know what to do here, say Y.
634 config RISCV_ISA_ZICBOZ
635 bool "Zicboz extension support for faster zeroing of memory"
636 depends on RISCV_ALTERNATIVE
639 Enable the use of the Zicboz extension (cbo.zero instruction)
642 The Zicboz extension is used for faster zeroing of memory.
644 If you don't know what to do here, say Y.
646 config TOOLCHAIN_HAS_ZIHINTPAUSE
649 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
650 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
651 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
653 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
655 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
656 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd
657 depends on AS_IS_GNU && AS_VERSION >= 23600
659 Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer
660 20191213 version, which moves some instructions from the I extension to
661 the Zicsr and Zifencei extensions. This requires explicitly specifying
662 Zicsr and Zifencei when binutils >= 2.38 or GCC >= 12.1.0. Zicsr
663 and Zifencei are supported in binutils from version 2.36 onwards.
664 To make life easier, and avoid forcing toolchains that default to a
665 newer ISA spec to version 2.2, relax the check to binutils >= 2.36.
666 For clang < 17 or GCC < 11.3.0, for which this is not possible or need
667 special treatment, this is dealt with in TOOLCHAIN_NEEDS_OLD_ISA_SPEC.
669 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
671 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
672 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
673 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d29f5d6ab513c52fd872f532c492e35ae9fd6671
674 depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC && GCC_VERSION < 110300)
676 Certain versions of clang and GCC do not support zicsr and zifencei via
677 -march. This option causes an older ISA spec compatible with these older
678 versions of clang and GCC to be passed to GAS, which has the same result
679 as passing zicsr and zifencei to -march.
685 Say N here if you want to disable all floating-point related procedure
688 If you don't know what to do here, say Y.
691 bool "Independent irq & softirq stacks" if EXPERT
693 select HAVE_IRQ_EXIT_ON_IRQ_STACK
694 select HAVE_SOFTIRQ_ON_OWN_STACK
696 Add independent irq & softirq stacks for percpu to prevent kernel stack
697 overflows. We may save some memory footprint by disabling IRQ_STACKS.
699 config THREAD_SIZE_ORDER
700 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
702 default 1 if 32BIT && !KASAN
703 default 3 if 64BIT && KASAN
706 Specify the Pages of thread stack size (from 4KB to 64KB), which also
707 affects irq stack size, which is equal to thread stack size.
709 config RISCV_MISALIGNED
711 select SYSCTL_ARCH_UNALIGN_ALLOW
713 Embed support for emulating misaligned loads and stores.
716 prompt "Unaligned Accesses Support"
717 default RISCV_PROBE_UNALIGNED_ACCESS
719 This determines the level of support for unaligned accesses. This
720 information is used by the kernel to perform optimizations. It is also
721 exposed to user space via the hwprobe syscall. The hardware will be
722 probed at boot by default.
724 config RISCV_PROBE_UNALIGNED_ACCESS
725 bool "Probe for hardware unaligned access support"
726 select RISCV_MISALIGNED
728 During boot, the kernel will run a series of tests to determine the
729 speed of unaligned accesses. This probing will dynamically determine
730 the speed of unaligned accesses on the underlying system. If unaligned
731 memory accesses trap into the kernel as they are not supported by the
732 system, the kernel will emulate the unaligned accesses to preserve the
735 config RISCV_EMULATED_UNALIGNED_ACCESS
736 bool "Emulate unaligned access where system support is missing"
737 select RISCV_MISALIGNED
739 If unaligned memory accesses trap into the kernel as they are not
740 supported by the system, the kernel will emulate the unaligned
741 accesses to preserve the UABI. When the underlying system does support
742 unaligned accesses, the unaligned accesses are assumed to be slow.
744 config RISCV_SLOW_UNALIGNED_ACCESS
745 bool "Assume the system supports slow unaligned memory accesses"
746 depends on NONPORTABLE
748 Assume that the system supports slow unaligned memory accesses. The
749 kernel and userspace programs may not be able to run at all on systems
750 that do not support unaligned memory accesses.
752 config RISCV_EFFICIENT_UNALIGNED_ACCESS
753 bool "Assume the system supports fast unaligned memory accesses"
754 depends on NONPORTABLE
755 select DCACHE_WORD_ACCESS if MMU
756 select HAVE_EFFICIENT_UNALIGNED_ACCESS
758 Assume that the system supports fast unaligned memory accesses. When
759 enabled, this option improves the performance of the kernel on such
760 systems. However, the kernel and userspace programs will run much more
761 slowly, or will not be able to run at all, on systems that do not
762 support efficient unaligned memory accesses.
766 endmenu # "Platform type"
768 menu "Kernel features"
770 source "kernel/Kconfig.hz"
773 bool "SBI v0.1 support"
776 This config allows kernel to use SBI v0.1 APIs. This will be
777 deprecated in future once legacy M-mode software are no longer in use.
779 config RISCV_BOOT_SPINWAIT
780 bool "Spinwait booting method"
782 default y if RISCV_SBI_V01 || RISCV_M_MODE
784 This enables support for booting Linux via spinwait method. In the
785 spinwait method, all cores randomly jump to Linux. One of the cores
786 gets chosen via lottery and all other keep spinning on a percpu
787 variable. This method cannot support CPU hotplug and sparse hartid
788 scheme. It should be only enabled for M-mode Linux or platforms relying
789 on older firmware without SBI HSM extension. All other platforms should
790 rely on ordered booting via SBI HSM extension which gets chosen
791 dynamically at runtime if the firmware supports it.
793 Since spinwait is incompatible with sparse hart IDs, it requires
794 NR_CPUS be large enough to contain the physical hart ID of the first
797 If unsure what to do here, say N.
799 config ARCH_SUPPORTS_KEXEC
802 config ARCH_SELECTS_KEXEC
805 select HOTPLUG_CPU if SMP
807 config ARCH_SUPPORTS_KEXEC_FILE
810 config ARCH_SELECTS_KEXEC_FILE
812 depends on KEXEC_FILE
813 select HAVE_IMA_KEXEC if IMA
816 config ARCH_SUPPORTS_KEXEC_PURGATORY
817 def_bool ARCH_SUPPORTS_KEXEC_FILE
819 config ARCH_SUPPORTS_CRASH_DUMP
822 config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
823 def_bool CRASH_RESERVE
826 bool "Kernel support for 32-bit U-mode"
828 depends on 64BIT && MMU
830 This option enables support for a 32-bit U-mode running under a 64-bit
831 kernel at S-mode. riscv32-specific components such as system calls,
832 the user helper functions (vdso), signal rt_frame functions and the
833 ptrace interface are handled appropriately by the kernel.
835 If you want to execute 32-bit userspace applications, say Y.
838 bool "Enable paravirtualization code"
841 This changes the kernel so it can modify itself when it is run
842 under a hypervisor, potentially improving performance significantly
843 over full virtualization.
845 config PARAVIRT_TIME_ACCOUNTING
846 bool "Paravirtual steal time accounting"
849 Select this option to enable fine granularity task steal time
850 accounting. Time spent executing other tasks in parallel with
851 the current vCPU is discounted from the vCPU power. To account for
852 that, there can be a small performance impact.
854 If in doubt, say N here.
857 bool "Build a relocatable kernel"
858 depends on MMU && 64BIT && !XIP_KERNEL
860 This builds a kernel as a Position Independent Executable (PIE),
861 which retains all relocation metadata required to relocate the
862 kernel binary at runtime to a different virtual address than the
863 address it was linked at.
864 Since RISCV uses the RELA relocation format, this requires a
865 relocation pass at runtime even if the kernel is loaded at the
866 same address it was linked at.
870 config RANDOMIZE_BASE
871 bool "Randomize the address of the kernel image"
873 depends on MMU && 64BIT && !XIP_KERNEL
875 Randomizes the virtual address at which the kernel image is
876 loaded, as a security feature that deters exploit attempts
877 relying on knowledge of the location of kernel internals.
879 It is the bootloader's job to provide entropy, by passing a
880 random u64 value in /chosen/kaslr-seed at kernel entry.
882 When booting via the UEFI stub, it will invoke the firmware's
883 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
884 to the kernel proper. In addition, it will randomise the physical
885 location of the kernel Image as well.
889 endmenu # "Kernel features"
894 string "Built-in kernel command line"
896 For most platforms, the arguments for the kernel's command line
897 are provided at run-time, during boot. However, there are cases
898 where either no arguments are being provided or the provided
899 arguments are insufficient or even invalid.
901 When that occurs, it is possible to define a built-in command
902 line here and choose how the kernel should use it later on.
905 prompt "Built-in command line usage" if CMDLINE != ""
906 default CMDLINE_FALLBACK
908 Choose how the kernel will handle the provided built-in command
911 config CMDLINE_FALLBACK
912 bool "Use bootloader kernel arguments if available"
914 Use the built-in command line as fallback in case we get nothing
915 during boot. This is the default behaviour.
917 config CMDLINE_EXTEND
918 bool "Extend bootloader kernel arguments"
920 The command-line arguments provided during boot will be
921 appended to the built-in command line. This is useful in
922 cases where the provided arguments are insufficient and
923 you don't want to or cannot modify them.
926 bool "Always use the default kernel command string"
928 Always use the built-in command line, even if we get one during
929 boot. This is useful in case you need to override the provided
930 command line on systems where you don't have or want control
939 bool "UEFI runtime support"
940 depends on OF && !XIP_KERNEL
943 select ARCH_SUPPORTS_ACPI if 64BIT
944 select EFI_GENERIC_STUB
945 select EFI_PARAMS_FROM_FDT
946 select EFI_RUNTIME_WRAPPERS
952 This option provides support for runtime services provided
953 by UEFI firmware (such as non-volatile variables, realtime
954 clock, and platform reset). A UEFI stub is also provided to
955 allow the kernel to be booted as an EFI application. This
956 is only useful on systems that have UEFI firmware.
958 config CC_HAVE_STACKPROTECTOR_TLS
959 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
961 config STACKPROTECTOR_PER_TASK
963 depends on !RANDSTRUCT
964 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
966 config PHYS_RAM_BASE_FIXED
967 bool "Explicitly specified physical RAM address"
968 depends on NONPORTABLE
972 hex "Platform Physical RAM address"
973 depends on PHYS_RAM_BASE_FIXED
976 This is the physical address of RAM in the system. It has to be
977 explicitly specified to run early relocations of read-write data
981 bool "Kernel Execute-In-Place from ROM"
982 depends on MMU && SPARSEMEM && NONPORTABLE
983 # This prevents XIP from being enabled by all{yes,mod}config, which
984 # fail to build since XIP doesn't support large kernels.
985 depends on !COMPILE_TEST
986 select PHYS_RAM_BASE_FIXED
988 Execute-In-Place allows the kernel to run from non-volatile storage
989 directly addressable by the CPU, such as NOR flash. This saves RAM
990 space since the text section of the kernel is not loaded from flash
991 to RAM. Read-write sections, such as the data section and stack,
992 are still copied to RAM. The XIP kernel is not compressed since
993 it has to run directly from flash, so it will take more space to
994 store it. The flash address used to link the kernel object files,
995 and for storing it, is configuration dependent. Therefore, if you
996 say Y here, you must know the proper physical address where to
997 store the kernel image depending on your own flash memory usage.
999 Also note that the make target becomes "make xipImage" rather than
1000 "make zImage" or "make Image". The final kernel binary to put in
1001 ROM memory will be arch/riscv/boot/xipImage.
1003 SPARSEMEM is required because the kernel text and rodata that are
1004 flash resident are not backed by memmap, then any attempt to get
1005 a struct page on those regions will trigger a fault.
1009 config XIP_PHYS_ADDR
1010 hex "XIP Kernel Physical Location"
1011 depends on XIP_KERNEL
1012 default "0x21000000"
1014 This is the physical address in your flash memory the kernel will
1015 be linked for and stored to. This address is dependent on your
1018 config RISCV_ISA_FALLBACK
1019 bool "Permit falling back to parsing riscv,isa for extension support by default"
1022 Parsing the "riscv,isa" devicetree property has been deprecated and
1023 replaced by a list of explicitly defined strings. For compatibility
1024 with existing platforms, the kernel will fall back to parsing the
1025 "riscv,isa" property if the replacements are not found.
1027 Selecting N here will result in a kernel that does not use the
1028 fallback, unless the commandline "riscv_isa_fallback" parameter is
1031 Please see the dt-binding, located at
1032 Documentation/devicetree/bindings/riscv/extensions.yaml for details
1033 on the replacement properties, "riscv,isa-base" and
1034 "riscv,isa-extensions".
1037 bool "Built-in device tree"
1038 depends on OF && NONPORTABLE
1040 Build a device tree into the Linux image.
1041 This option should be selected if no bootloader is being used.
1045 config BUILTIN_DTB_SOURCE
1046 string "Built-in device tree source"
1047 depends on BUILTIN_DTB
1049 DTS file path (without suffix, relative to arch/riscv/boot/dts)
1050 for the DTS file that will be used to produce the DTB linked into the
1053 endmenu # "Boot options"
1057 default !NONPORTABLE
1062 config ARCH_PROC_KCORE_TEXT
1065 menu "Power management options"
1067 source "kernel/power/Kconfig"
1069 config ARCH_HIBERNATION_POSSIBLE
1072 config ARCH_HIBERNATION_HEADER
1073 def_bool HIBERNATION
1075 config ARCH_SUSPEND_POSSIBLE
1078 endmenu # "Power management options"
1080 menu "CPU Power Management"
1082 source "drivers/cpuidle/Kconfig"
1084 source "drivers/cpufreq/Kconfig"
1086 endmenu # "CPU Power Management"
1088 source "arch/riscv/kvm/Kconfig"
1090 source "drivers/acpi/Kconfig"