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 !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
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_SAMPLE_FTRACE_DIRECT
159 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
160 select HAVE_STACKPROTECTOR
161 select HAVE_SYSCALL_TRACEPOINTS
162 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
164 select IRQ_FORCED_THREADING
165 select KASAN_VMALLOC if KASAN
166 select LOCK_MM_AND_FIND_VMA
167 select MMU_GATHER_RCU_TABLE_FREE if SMP && MMU
168 select MODULES_USE_ELF_RELA if MODULES
169 select MODULE_SECTIONS if MODULES
171 select OF_EARLY_FLATTREE
173 select PCI_DOMAINS_GENERIC if PCI
174 select PCI_MSI if PCI
175 select RISCV_ALTERNATIVE if !XIP_KERNEL
177 select RISCV_TIMER if RISCV_SBI
180 select SYSCTL_EXCEPTION_TRACE
181 select THREAD_INFO_IN_TASK
182 select TRACE_IRQFLAGS_SUPPORT
183 select UACCESS_MEMCPY if !MMU
184 select ZONE_DMA32 if 64BIT
186 config CLANG_SUPPORTS_DYNAMIC_FTRACE
188 # https://github.com/ClangBuiltLinux/linux/issues/1817
189 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
191 config GCC_SUPPORTS_DYNAMIC_FTRACE
193 depends on $(cc-option,-fpatchable-function-entry=8)
195 config HAVE_SHADOW_CALL_STACK
196 def_bool $(cc-option,-fsanitize=shadow-call-stack)
197 # https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/a484e843e6eeb51f0cb7b8819e50da6d2444d769
198 depends on $(ld-option,--no-relax-gp)
200 config RISCV_USE_LINKER_RELAXATION
202 # https://github.com/llvm/llvm-project/commit/6611d58f5bbcbec77262d392e2923e1d680f6985
203 depends on !LD_IS_LLD || LLD_VERSION >= 150000
205 # https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6
206 config ARCH_HAS_BROKEN_DWARF5
208 depends on RISCV_USE_LINKER_RELAXATION
209 # https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a
210 depends on AS_IS_LLVM && AS_VERSION < 180000
211 # https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77
212 depends on LD_IS_LLD && LLD_VERSION < 180000
214 config ARCH_MMAP_RND_BITS_MIN
218 config ARCH_MMAP_RND_COMPAT_BITS_MIN
221 # max bits determined by the following formula:
222 # VA_BITS - PAGE_SHIFT - 3
223 config ARCH_MMAP_RND_BITS_MAX
224 default 24 if 64BIT # SV39 based
227 config ARCH_MMAP_RND_COMPAT_BITS_MAX
230 # set if we run in machine mode, cleared if we run in supervisor mode
235 # set if we are running in S-mode and can use SBI calls
238 depends on !RISCV_M_MODE
242 bool "MMU-based Paged Memory Management Support"
245 Select if you want MMU-based virtualised addressing space
246 support by paged memory management. If unsure, say 'Y'.
250 default 0xC0000000 if 32BIT && MMU
251 default 0x80000000 if !MMU
252 default 0xff60000000000000 if 64BIT
254 config KASAN_SHADOW_OFFSET
256 depends on KASAN_GENERIC
257 default 0xdfffffff00000000 if 64BIT
258 default 0xffffffff if 32BIT
260 config ARCH_FLATMEM_ENABLE
263 config ARCH_SPARSEMEM_ENABLE
266 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
267 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
269 config ARCH_SELECT_MEMORY_MODEL
270 def_bool ARCH_SPARSEMEM_ENABLE
272 config ARCH_SUPPORTS_UPROBES
275 config STACKTRACE_SUPPORT
281 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
283 config GENERIC_BUG_RELATIVE_POINTERS
286 config GENERIC_CALIBRATE_DELAY
292 config GENERIC_HWEIGHT
295 config FIX_EARLYCON_MEM
298 config PGTABLE_LEVELS
303 config LOCKDEP_SUPPORT
306 config RISCV_DMA_NONCOHERENT
308 select ARCH_HAS_DMA_PREP_COHERENT
309 select ARCH_HAS_SETUP_DMA_OPS
310 select ARCH_HAS_SYNC_DMA_FOR_CPU
311 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
312 select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB
314 config RISCV_NONSTANDARD_CACHE_OPS
317 This enables function pointer support for non-standard noncoherent
318 systems to handle cache management.
321 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
323 config AS_HAS_OPTION_ARCH
324 # https://github.com/llvm/llvm-project/commit/9e8ed3403c191ab9c4903e8eeb8f732ff8a43cb4
326 depends on $(as-instr, .option arch$(comma) +m)
328 source "arch/riscv/Kconfig.socs"
329 source "arch/riscv/Kconfig.errata"
334 bool "Allow configurations that result in non-portable kernels"
336 RISC-V kernel binaries are compatible between all known systems
337 whenever possible, but there are some use cases that can only be
338 satisfied by configurations that result in kernel binaries that are
339 not portable between systems.
341 Selecting N does not guarantee kernels will be portable to all known
342 systems. Selecting any of the options guarded by NONPORTABLE will
343 result in kernel binaries that are unlikely to be portable between
352 This selects the base ISA that this kernel will target and must match
357 depends on NONPORTABLE
359 select GENERIC_LIB_ASHLDI3
360 select GENERIC_LIB_ASHRDI3
361 select GENERIC_LIB_LSHRDI3
362 select GENERIC_LIB_UCMPDI2
367 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
368 select SWIOTLB if MMU
372 # We must be able to map all physical memory into the kernel, but the compiler
373 # is still a bit more efficient when generating code if it's setup in a manner
374 # such that it can only map 2GiB of memory.
376 prompt "Kernel Code Model"
377 default CMODEL_MEDLOW if 32BIT
378 default CMODEL_MEDANY if 64BIT
381 bool "medium low code model"
383 bool "medium any code model"
386 config MODULE_SECTIONS
388 select HAVE_MOD_ARCH_SPECIFIC
391 bool "Symmetric Multi-Processing"
393 This enables support for systems with more than one CPU. If
394 you say N here, the kernel will run on single and
395 multiprocessor machines, but will use only one CPU of a
396 multiprocessor machine. If you say Y here, the kernel will run
397 on many, but not all, single processor machines. On a single
398 processor machine, the kernel will run faster if you say N
401 If you don't know what to do here, say N.
404 bool "Multi-core scheduler support"
407 Multi-core scheduler support improves the CPU scheduler's decision
408 making when dealing with multi-core CPU chips at a cost of slightly
409 increased overhead in some places. If unsure say N here.
412 int "Maximum number of CPUs (2-512)"
414 range 2 512 if !RISCV_SBI_V01
415 range 2 32 if RISCV_SBI_V01 && 32BIT
416 range 2 64 if RISCV_SBI_V01 && 64BIT
417 default "32" if 32BIT
418 default "64" if 64BIT
421 bool "Support for hot-pluggable CPUs"
423 select GENERIC_IRQ_MIGRATION
426 Say Y here to experiment with turning CPUs off and on. CPUs
427 can be controlled through /sys/devices/system/cpu.
429 Say N if you want to disable CPU hotplug.
440 # Common NUMA Features
442 bool "NUMA Memory Allocation and Scheduler Support"
443 depends on SMP && MMU
444 select ARCH_SUPPORTS_NUMA_BALANCING
445 select GENERIC_ARCH_NUMA
446 select HAVE_SETUP_PER_CPU_AREA
447 select NEED_PER_CPU_EMBED_FIRST_CHUNK
448 select NEED_PER_CPU_PAGE_FIRST_CHUNK
450 select USE_PERCPU_NUMA_NODE_ID
452 Enable NUMA (Non-Uniform Memory Access) support.
454 The kernel will try to allocate memory used by a CPU on the
455 local memory of the CPU and add some more NUMA awareness to the kernel.
458 int "Maximum NUMA Nodes (as a power of 2)"
463 Specify the maximum number of NUMA Nodes available on the target
464 system. Increases memory reserved to accommodate various tables.
466 config RISCV_ALTERNATIVE
468 depends on !XIP_KERNEL
470 This Kconfig allows the kernel to automatically patch the
471 erratum or cpufeature required by the execution platform at run
472 time. The code patching overhead is minimal, as it's only done
473 once at boot and once on each module load.
475 config RISCV_ALTERNATIVE_EARLY
477 depends on RISCV_ALTERNATIVE
479 Allows early patching of the kernel for special errata
482 bool "Emit compressed instructions when building Linux"
485 Adds "C" to the ISA subsets that the toolchain is allowed to emit
486 when building Linux, which results in compressed instructions in the
489 If you don't know what to do here, say Y.
491 config RISCV_ISA_SVNAPOT
492 bool "Svnapot extension support for supervisor mode NAPOT pages"
493 depends on 64BIT && MMU
494 depends on RISCV_ALTERNATIVE
497 Allow kernel to detect the Svnapot ISA-extension dynamically at boot
498 time and enable its usage.
500 The Svnapot extension is used to mark contiguous PTEs as a range
501 of contiguous virtual-to-physical translations for a naturally
502 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
503 size. When HUGETLBFS is also selected this option unconditionally
504 allocates some memory for each NAPOT page size supported by the kernel.
505 When optimizing for low memory consumption and for platforms without
506 the Svnapot extension, it may be better to say N here.
508 If you don't know what to do here, say Y.
510 config RISCV_ISA_SVPBMT
511 bool "Svpbmt extension support for supervisor mode page-based memory types"
512 depends on 64BIT && MMU
513 depends on RISCV_ALTERNATIVE
516 Adds support to dynamically detect the presence of the Svpbmt
517 ISA-extension (Supervisor-mode: page-based memory types) and
520 The memory type for a page contains a combination of attributes
521 that indicate the cacheability, idempotency, and ordering
522 properties for access to that page.
524 The Svpbmt extension is only available on 64-bit cpus.
526 If you don't know what to do here, say Y.
528 config TOOLCHAIN_HAS_V
531 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
532 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
533 depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
534 depends on AS_HAS_OPTION_ARCH
537 bool "VECTOR extension support"
538 depends on TOOLCHAIN_HAS_V
540 select DYNAMIC_SIGFRAME
543 Say N here if you want to disable all vector related procedure
546 If you don't know what to do here, say Y.
548 config RISCV_ISA_V_DEFAULT_ENABLE
549 bool "Enable userspace Vector by default"
550 depends on RISCV_ISA_V
553 Say Y here if you want to enable Vector in userspace by default.
554 Otherwise, userspace has to make explicit prctl() call to enable
555 Vector, or enable it via the sysctl interface.
557 If you don't know what to do here, say Y.
559 config RISCV_ISA_V_UCOPY_THRESHOLD
560 int "Threshold size for vectorized user copies"
561 depends on RISCV_ISA_V
564 Prefer using vectorized copy_to_user()/copy_from_user() when the
565 workload size exceeds this value.
567 config RISCV_ISA_V_PREEMPTIVE
568 bool "Run kernel-mode Vector with kernel preemption"
569 depends on PREEMPTION
570 depends on RISCV_ISA_V
573 Usually, in-kernel SIMD routines are run with preemption disabled.
574 Functions which envoke long running SIMD thus must yield core's
575 vector unit to prevent blocking other tasks for too long.
577 This config allows kernel to run SIMD without explicitly disable
578 preemption. Enabling this config will result in higher memory
579 consumption due to the allocation of per-task's kernel Vector context.
581 config TOOLCHAIN_HAS_ZBB
584 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
585 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
586 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
587 depends on AS_HAS_OPTION_ARCH
589 # This symbol indicates that the toolchain supports all v1.0 vector crypto
590 # extensions, including Zvk*, Zvbb, and Zvbc. LLVM added all of these at once.
591 # binutils added all except Zvkb, then added Zvkb. So we just check for Zvkb.
592 config TOOLCHAIN_HAS_VECTOR_CRYPTO
593 def_bool $(as-instr, .option arch$(comma) +v$(comma) +zvkb)
594 depends on AS_HAS_OPTION_ARCH
597 bool "Zbb extension support for bit manipulation instructions"
598 depends on TOOLCHAIN_HAS_ZBB
600 depends on RISCV_ALTERNATIVE
603 Adds support to dynamically detect the presence of the ZBB
604 extension (basic bit manipulation) and enable its usage.
606 The Zbb extension provides instructions to accelerate a number
607 of bit-specific operations (count bit population, sign extending,
610 If you don't know what to do here, say Y.
612 config RISCV_ISA_ZICBOM
613 bool "Zicbom extension support for non-coherent DMA operation"
615 depends on RISCV_ALTERNATIVE
617 select RISCV_DMA_NONCOHERENT
618 select DMA_DIRECT_REMAP
620 Adds support to dynamically detect the presence of the ZICBOM
621 extension (Cache Block Management Operations) and enable its
624 The Zicbom extension can be used to handle for example
625 non-coherent DMA support on devices that need it.
627 If you don't know what to do here, say Y.
629 config RISCV_ISA_ZICBOZ
630 bool "Zicboz extension support for faster zeroing of memory"
632 depends on RISCV_ALTERNATIVE
635 Enable the use of the Zicboz extension (cbo.zero instruction)
638 The Zicboz extension is used for faster zeroing of memory.
640 If you don't know what to do here, say Y.
642 config TOOLCHAIN_HAS_ZIHINTPAUSE
645 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
646 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
647 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
649 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
651 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
652 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd
653 depends on AS_IS_GNU && AS_VERSION >= 23600
655 Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer
656 20191213 version, which moves some instructions from the I extension to
657 the Zicsr and Zifencei extensions. This requires explicitly specifying
658 Zicsr and Zifencei when binutils >= 2.38 or GCC >= 12.1.0. Zicsr
659 and Zifencei are supported in binutils from version 2.36 onwards.
660 To make life easier, and avoid forcing toolchains that default to a
661 newer ISA spec to version 2.2, relax the check to binutils >= 2.36.
662 For clang < 17 or GCC < 11.3.0, for which this is not possible or need
663 special treatment, this is dealt with in TOOLCHAIN_NEEDS_OLD_ISA_SPEC.
665 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
667 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
668 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
669 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d29f5d6ab513c52fd872f532c492e35ae9fd6671
670 depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC && GCC_VERSION < 110300)
672 Certain versions of clang and GCC do not support zicsr and zifencei via
673 -march. This option causes an older ISA spec compatible with these older
674 versions of clang and GCC to be passed to GAS, which has the same result
675 as passing zicsr and zifencei to -march.
681 Say N here if you want to disable all floating-point related procedure
684 If you don't know what to do here, say Y.
687 bool "Independent irq & softirq stacks" if EXPERT
689 select HAVE_IRQ_EXIT_ON_IRQ_STACK
690 select HAVE_SOFTIRQ_ON_OWN_STACK
692 Add independent irq & softirq stacks for percpu to prevent kernel stack
693 overflows. We may save some memory footprint by disabling IRQ_STACKS.
695 config THREAD_SIZE_ORDER
696 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
698 default 1 if 32BIT && !KASAN
699 default 3 if 64BIT && KASAN
702 Specify the Pages of thread stack size (from 4KB to 64KB), which also
703 affects irq stack size, which is equal to thread stack size.
705 config RISCV_MISALIGNED
707 select SYSCTL_ARCH_UNALIGN_ALLOW
709 Embed support for emulating misaligned loads and stores.
712 prompt "Unaligned Accesses Support"
713 default RISCV_PROBE_UNALIGNED_ACCESS
715 This determines the level of support for unaligned accesses. This
716 information is used by the kernel to perform optimizations. It is also
717 exposed to user space via the hwprobe syscall. The hardware will be
718 probed at boot by default.
720 config RISCV_PROBE_UNALIGNED_ACCESS
721 bool "Probe for hardware unaligned access support"
722 select RISCV_MISALIGNED
724 During boot, the kernel will run a series of tests to determine the
725 speed of unaligned accesses. This probing will dynamically determine
726 the speed of unaligned accesses on the underlying system. If unaligned
727 memory accesses trap into the kernel as they are not supported by the
728 system, the kernel will emulate the unaligned accesses to preserve the
731 config RISCV_EMULATED_UNALIGNED_ACCESS
732 bool "Emulate unaligned access where system support is missing"
733 select RISCV_MISALIGNED
735 If unaligned memory accesses trap into the kernel as they are not
736 supported by the system, the kernel will emulate the unaligned
737 accesses to preserve the UABI. When the underlying system does support
738 unaligned accesses, the unaligned accesses are assumed to be slow.
740 config RISCV_SLOW_UNALIGNED_ACCESS
741 bool "Assume the system supports slow unaligned memory accesses"
742 depends on NONPORTABLE
744 Assume that the system supports slow unaligned memory accesses. The
745 kernel and userspace programs may not be able to run at all on systems
746 that do not support unaligned memory accesses.
748 config RISCV_EFFICIENT_UNALIGNED_ACCESS
749 bool "Assume the system supports fast unaligned memory accesses"
750 depends on NONPORTABLE
751 select DCACHE_WORD_ACCESS if MMU
752 select HAVE_EFFICIENT_UNALIGNED_ACCESS
754 Assume that the system supports fast unaligned memory accesses. When
755 enabled, this option improves the performance of the kernel on such
756 systems. However, the kernel and userspace programs will run much more
757 slowly, or will not be able to run at all, on systems that do not
758 support efficient unaligned memory accesses.
762 endmenu # "Platform type"
764 menu "Kernel features"
766 source "kernel/Kconfig.hz"
769 bool "SBI v0.1 support"
772 This config allows kernel to use SBI v0.1 APIs. This will be
773 deprecated in future once legacy M-mode software are no longer in use.
775 config RISCV_BOOT_SPINWAIT
776 bool "Spinwait booting method"
778 default y if RISCV_SBI_V01 || RISCV_M_MODE
780 This enables support for booting Linux via spinwait method. In the
781 spinwait method, all cores randomly jump to Linux. One of the cores
782 gets chosen via lottery and all other keep spinning on a percpu
783 variable. This method cannot support CPU hotplug and sparse hartid
784 scheme. It should be only enabled for M-mode Linux or platforms relying
785 on older firmware without SBI HSM extension. All other platforms should
786 rely on ordered booting via SBI HSM extension which gets chosen
787 dynamically at runtime if the firmware supports it.
789 Since spinwait is incompatible with sparse hart IDs, it requires
790 NR_CPUS be large enough to contain the physical hart ID of the first
793 If unsure what to do here, say N.
795 config ARCH_SUPPORTS_KEXEC
798 config ARCH_SELECTS_KEXEC
801 select HOTPLUG_CPU if SMP
803 config ARCH_SUPPORTS_KEXEC_FILE
806 config ARCH_SELECTS_KEXEC_FILE
808 depends on KEXEC_FILE
809 select HAVE_IMA_KEXEC if IMA
812 config ARCH_SUPPORTS_KEXEC_PURGATORY
813 def_bool ARCH_SUPPORTS_KEXEC_FILE
815 config ARCH_SUPPORTS_CRASH_DUMP
818 config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
819 def_bool CRASH_RESERVE
822 bool "Kernel support for 32-bit U-mode"
824 depends on 64BIT && MMU
826 This option enables support for a 32-bit U-mode running under a 64-bit
827 kernel at S-mode. riscv32-specific components such as system calls,
828 the user helper functions (vdso), signal rt_frame functions and the
829 ptrace interface are handled appropriately by the kernel.
831 If you want to execute 32-bit userspace applications, say Y.
834 bool "Enable paravirtualization code"
837 This changes the kernel so it can modify itself when it is run
838 under a hypervisor, potentially improving performance significantly
839 over full virtualization.
841 config PARAVIRT_TIME_ACCOUNTING
842 bool "Paravirtual steal time accounting"
845 Select this option to enable fine granularity task steal time
846 accounting. Time spent executing other tasks in parallel with
847 the current vCPU is discounted from the vCPU power. To account for
848 that, there can be a small performance impact.
850 If in doubt, say N here.
853 bool "Build a relocatable kernel"
854 depends on MMU && 64BIT && !XIP_KERNEL
856 This builds a kernel as a Position Independent Executable (PIE),
857 which retains all relocation metadata required to relocate the
858 kernel binary at runtime to a different virtual address than the
859 address it was linked at.
860 Since RISCV uses the RELA relocation format, this requires a
861 relocation pass at runtime even if the kernel is loaded at the
862 same address it was linked at.
866 config RANDOMIZE_BASE
867 bool "Randomize the address of the kernel image"
869 depends on MMU && 64BIT && !XIP_KERNEL
871 Randomizes the virtual address at which the kernel image is
872 loaded, as a security feature that deters exploit attempts
873 relying on knowledge of the location of kernel internals.
875 It is the bootloader's job to provide entropy, by passing a
876 random u64 value in /chosen/kaslr-seed at kernel entry.
878 When booting via the UEFI stub, it will invoke the firmware's
879 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
880 to the kernel proper. In addition, it will randomise the physical
881 location of the kernel Image as well.
885 endmenu # "Kernel features"
890 string "Built-in kernel command line"
892 For most platforms, the arguments for the kernel's command line
893 are provided at run-time, during boot. However, there are cases
894 where either no arguments are being provided or the provided
895 arguments are insufficient or even invalid.
897 When that occurs, it is possible to define a built-in command
898 line here and choose how the kernel should use it later on.
901 prompt "Built-in command line usage" if CMDLINE != ""
902 default CMDLINE_FALLBACK
904 Choose how the kernel will handle the provided built-in command
907 config CMDLINE_FALLBACK
908 bool "Use bootloader kernel arguments if available"
910 Use the built-in command line as fallback in case we get nothing
911 during boot. This is the default behaviour.
913 config CMDLINE_EXTEND
914 bool "Extend bootloader kernel arguments"
916 The command-line arguments provided during boot will be
917 appended to the built-in command line. This is useful in
918 cases where the provided arguments are insufficient and
919 you don't want to or cannot modify them.
922 bool "Always use the default kernel command string"
924 Always use the built-in command line, even if we get one during
925 boot. This is useful in case you need to override the provided
926 command line on systems where you don't have or want control
935 bool "UEFI runtime support"
936 depends on OF && !XIP_KERNEL
939 select ARCH_SUPPORTS_ACPI if 64BIT
940 select EFI_GENERIC_STUB
941 select EFI_PARAMS_FROM_FDT
942 select EFI_RUNTIME_WRAPPERS
948 This option provides support for runtime services provided
949 by UEFI firmware (such as non-volatile variables, realtime
950 clock, and platform reset). A UEFI stub is also provided to
951 allow the kernel to be booted as an EFI application. This
952 is only useful on systems that have UEFI firmware.
954 config CC_HAVE_STACKPROTECTOR_TLS
955 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
957 config STACKPROTECTOR_PER_TASK
959 depends on !RANDSTRUCT
960 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
962 config PHYS_RAM_BASE_FIXED
963 bool "Explicitly specified physical RAM address"
964 depends on NONPORTABLE
968 hex "Platform Physical RAM address"
969 depends on PHYS_RAM_BASE_FIXED
972 This is the physical address of RAM in the system. It has to be
973 explicitly specified to run early relocations of read-write data
977 bool "Kernel Execute-In-Place from ROM"
978 depends on MMU && SPARSEMEM && NONPORTABLE
979 # This prevents XIP from being enabled by all{yes,mod}config, which
980 # fail to build since XIP doesn't support large kernels.
981 depends on !COMPILE_TEST
982 select PHYS_RAM_BASE_FIXED
984 Execute-In-Place allows the kernel to run from non-volatile storage
985 directly addressable by the CPU, such as NOR flash. This saves RAM
986 space since the text section of the kernel is not loaded from flash
987 to RAM. Read-write sections, such as the data section and stack,
988 are still copied to RAM. The XIP kernel is not compressed since
989 it has to run directly from flash, so it will take more space to
990 store it. The flash address used to link the kernel object files,
991 and for storing it, is configuration dependent. Therefore, if you
992 say Y here, you must know the proper physical address where to
993 store the kernel image depending on your own flash memory usage.
995 Also note that the make target becomes "make xipImage" rather than
996 "make zImage" or "make Image". The final kernel binary to put in
997 ROM memory will be arch/riscv/boot/xipImage.
999 SPARSEMEM is required because the kernel text and rodata that are
1000 flash resident are not backed by memmap, then any attempt to get
1001 a struct page on those regions will trigger a fault.
1005 config XIP_PHYS_ADDR
1006 hex "XIP Kernel Physical Location"
1007 depends on XIP_KERNEL
1008 default "0x21000000"
1010 This is the physical address in your flash memory the kernel will
1011 be linked for and stored to. This address is dependent on your
1014 config RISCV_ISA_FALLBACK
1015 bool "Permit falling back to parsing riscv,isa for extension support by default"
1018 Parsing the "riscv,isa" devicetree property has been deprecated and
1019 replaced by a list of explicitly defined strings. For compatibility
1020 with existing platforms, the kernel will fall back to parsing the
1021 "riscv,isa" property if the replacements are not found.
1023 Selecting N here will result in a kernel that does not use the
1024 fallback, unless the commandline "riscv_isa_fallback" parameter is
1027 Please see the dt-binding, located at
1028 Documentation/devicetree/bindings/riscv/extensions.yaml for details
1029 on the replacement properties, "riscv,isa-base" and
1030 "riscv,isa-extensions".
1033 bool "Built-in device tree"
1034 depends on OF && NONPORTABLE
1036 Build a device tree into the Linux image.
1037 This option should be selected if no bootloader is being used.
1041 config BUILTIN_DTB_SOURCE
1042 string "Built-in device tree source"
1043 depends on BUILTIN_DTB
1045 DTS file path (without suffix, relative to arch/riscv/boot/dts)
1046 for the DTS file that will be used to produce the DTB linked into the
1049 endmenu # "Boot options"
1053 default !NONPORTABLE
1058 config ARCH_PROC_KCORE_TEXT
1061 menu "Power management options"
1063 source "kernel/power/Kconfig"
1065 config ARCH_HIBERNATION_POSSIBLE
1068 config ARCH_HIBERNATION_HEADER
1069 def_bool HIBERNATION
1071 config ARCH_SUSPEND_POSSIBLE
1074 endmenu # "Power management options"
1076 menu "CPU Power Management"
1078 source "drivers/cpuidle/Kconfig"
1080 source "drivers/cpufreq/Kconfig"
1082 endmenu # "CPU Power Management"
1084 source "arch/riscv/kvm/Kconfig"
1086 source "drivers/acpi/Kconfig"