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_MMIOWB
31 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
32 select ARCH_HAS_PMEM_API
33 select ARCH_HAS_PTE_SPECIAL
34 select ARCH_HAS_SET_DIRECT_MAP if MMU
35 select ARCH_HAS_SET_MEMORY if MMU
36 select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
37 select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
38 select ARCH_HAS_SYSCALL_WRAPPER
39 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
40 select ARCH_HAS_UBSAN_SANITIZE_ALL
41 select ARCH_HAS_VDSO_DATA
42 select ARCH_KEEP_MEMBLOCK if ACPI
43 select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
44 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
46 select ARCH_SUPPORTS_ATOMIC_RMW
47 select ARCH_SUPPORTS_CFI_CLANG
48 select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
49 select ARCH_SUPPORTS_HUGETLBFS if MMU
50 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
51 select ARCH_SUPPORTS_PER_VMA_LOCK if MMU
52 select ARCH_SUPPORTS_SHADOW_CALL_STACK if HAVE_SHADOW_CALL_STACK
53 select ARCH_USE_MEMTEST
54 select ARCH_USE_QUEUED_RWLOCKS
55 select ARCH_USES_CFI_TRAPS if CFI_CLANG
56 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP && MMU
57 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
58 select ARCH_WANT_FRAME_POINTERS
59 select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
60 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
61 select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
62 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
63 select ARCH_WANTS_NO_INSTR
64 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
65 select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
66 select BUILDTIME_TABLE_SORT if MMU
67 select CLINT_TIMER if !MMU
68 select CLONE_BACKWARDS
70 select CPU_PM if CPU_IDLE || HIBERNATION || SUSPEND
72 select FRAME_POINTER if PERF_EVENTS || (FUNCTION_TRACER && !DYNAMIC_FTRACE)
73 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if DYNAMIC_FTRACE
74 select GENERIC_ARCH_TOPOLOGY
75 select GENERIC_ATOMIC64 if !64BIT
76 select GENERIC_CLOCKEVENTS_BROADCAST if SMP
77 select GENERIC_CPU_DEVICES
78 select GENERIC_EARLY_IOREMAP
80 select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
81 select GENERIC_IDLE_POLL_SETUP
82 select GENERIC_IOREMAP if MMU
83 select GENERIC_IRQ_IPI if SMP
84 select GENERIC_IRQ_IPI_MUX if SMP
85 select GENERIC_IRQ_MULTI_HANDLER
86 select GENERIC_IRQ_SHOW
87 select GENERIC_IRQ_SHOW_LEVEL
88 select GENERIC_LIB_DEVMEM_IS_ALLOWED
89 select GENERIC_PCI_IOMAP
90 select GENERIC_PTDUMP if MMU
91 select GENERIC_SCHED_CLOCK
92 select GENERIC_SMP_IDLE_THREAD
93 select GENERIC_TIME_VSYSCALL if MMU && 64BIT
94 select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
95 select HARDIRQS_SW_RESEND
96 select HAS_IOPORT if MMU
97 select HAVE_ARCH_AUDITSYSCALL
98 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
99 select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT && !XIP_KERNEL
100 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
101 select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
102 select HAVE_ARCH_KASAN if MMU && 64BIT
103 select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
104 select HAVE_ARCH_KFENCE if MMU && 64BIT
105 select HAVE_ARCH_KGDB if !XIP_KERNEL
106 select HAVE_ARCH_KGDB_QXFER_PKT
107 select HAVE_ARCH_MMAP_RND_BITS if MMU
108 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
109 select HAVE_ARCH_SECCOMP_FILTER
110 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
111 select HAVE_ARCH_TRACEHOOK
112 select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
113 select HAVE_ARCH_USERFAULTFD_MINOR if 64BIT && USERFAULTFD
114 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT
115 select HAVE_ASM_MODVERSIONS
116 select HAVE_CONTEXT_TRACKING_USER
117 select HAVE_DEBUG_KMEMLEAK
118 select HAVE_DMA_CONTIGUOUS if MMU
119 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
120 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
121 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
122 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
123 select HAVE_FUNCTION_GRAPH_TRACER
124 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
125 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
126 select HAVE_EBPF_JIT if MMU
127 select HAVE_FUNCTION_ARG_ACCESS_API
128 select HAVE_FUNCTION_ERROR_INJECTION
129 select HAVE_GCC_PLUGINS
130 select HAVE_GENERIC_VDSO if MMU && 64BIT
131 select HAVE_IRQ_TIME_ACCOUNTING
132 select HAVE_KPROBES if !XIP_KERNEL
133 select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
134 select HAVE_KRETPROBES if !XIP_KERNEL
135 # https://github.com/ClangBuiltLinux/linux/issues/1881
136 select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD
140 select HAVE_PERF_EVENTS
141 select HAVE_PERF_REGS
142 select HAVE_PERF_USER_STACK_DUMP
143 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
144 select HAVE_PREEMPT_DYNAMIC_KEY if !XIP_KERNEL
145 select HAVE_REGS_AND_STACK_ACCESS_API
146 select HAVE_RETHOOK if !XIP_KERNEL
148 select HAVE_SAMPLE_FTRACE_DIRECT
149 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
150 select HAVE_STACKPROTECTOR
151 select HAVE_SYSCALL_TRACEPOINTS
152 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
154 select IRQ_FORCED_THREADING
155 select KASAN_VMALLOC if KASAN
156 select LOCK_MM_AND_FIND_VMA
157 select MODULES_USE_ELF_RELA if MODULES
158 select MODULE_SECTIONS if MODULES
160 select OF_EARLY_FLATTREE
162 select PCI_DOMAINS_GENERIC if PCI
163 select PCI_MSI if PCI
164 select RISCV_ALTERNATIVE if !XIP_KERNEL
166 select RISCV_TIMER if RISCV_SBI
169 select SYSCTL_EXCEPTION_TRACE
170 select THREAD_INFO_IN_TASK
171 select TRACE_IRQFLAGS_SUPPORT
172 select UACCESS_MEMCPY if !MMU
173 select ZONE_DMA32 if 64BIT
175 config CLANG_SUPPORTS_DYNAMIC_FTRACE
177 # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e
178 depends on CLANG_VERSION >= 130000
179 # https://github.com/ClangBuiltLinux/linux/issues/1817
180 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
182 config GCC_SUPPORTS_DYNAMIC_FTRACE
184 depends on $(cc-option,-fpatchable-function-entry=8)
186 config HAVE_SHADOW_CALL_STACK
187 def_bool $(cc-option,-fsanitize=shadow-call-stack)
188 # https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/a484e843e6eeb51f0cb7b8819e50da6d2444d769
189 depends on $(ld-option,--no-relax-gp)
191 config RISCV_USE_LINKER_RELAXATION
193 # https://github.com/llvm/llvm-project/commit/6611d58f5bbcbec77262d392e2923e1d680f6985
194 depends on !LD_IS_LLD || LLD_VERSION >= 150000
196 # https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6
197 config ARCH_HAS_BROKEN_DWARF5
199 depends on RISCV_USE_LINKER_RELAXATION
200 # https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a
201 depends on AS_IS_LLVM && AS_VERSION < 180000
202 # https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77
203 depends on LD_IS_LLD && LLD_VERSION < 180000
205 config ARCH_MMAP_RND_BITS_MIN
209 config ARCH_MMAP_RND_COMPAT_BITS_MIN
212 # max bits determined by the following formula:
213 # VA_BITS - PAGE_SHIFT - 3
214 config ARCH_MMAP_RND_BITS_MAX
215 default 24 if 64BIT # SV39 based
218 config ARCH_MMAP_RND_COMPAT_BITS_MAX
221 # set if we run in machine mode, cleared if we run in supervisor mode
226 # set if we are running in S-mode and can use SBI calls
229 depends on !RISCV_M_MODE
233 bool "MMU-based Paged Memory Management Support"
236 Select if you want MMU-based virtualised addressing space
237 support by paged memory management. If unsure, say 'Y'.
241 default 0xC0000000 if 32BIT && MMU
242 default 0x80000000 if !MMU
243 default 0xff60000000000000 if 64BIT
245 config KASAN_SHADOW_OFFSET
247 depends on KASAN_GENERIC
248 default 0xdfffffff00000000 if 64BIT
249 default 0xffffffff if 32BIT
251 config ARCH_FLATMEM_ENABLE
254 config ARCH_SPARSEMEM_ENABLE
257 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
258 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
260 config ARCH_SELECT_MEMORY_MODEL
261 def_bool ARCH_SPARSEMEM_ENABLE
263 config ARCH_SUPPORTS_UPROBES
266 config STACKTRACE_SUPPORT
272 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
274 config GENERIC_BUG_RELATIVE_POINTERS
277 config GENERIC_CALIBRATE_DELAY
283 config GENERIC_HWEIGHT
286 config FIX_EARLYCON_MEM
289 config PGTABLE_LEVELS
294 config LOCKDEP_SUPPORT
297 config RISCV_DMA_NONCOHERENT
299 select ARCH_HAS_DMA_PREP_COHERENT
300 select ARCH_HAS_SETUP_DMA_OPS
301 select ARCH_HAS_SYNC_DMA_FOR_CPU
302 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
303 select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB
305 config RISCV_NONSTANDARD_CACHE_OPS
308 This enables function pointer support for non-standard noncoherent
309 systems to handle cache management.
312 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
314 config AS_HAS_OPTION_ARCH
315 # https://reviews.llvm.org/D123515
317 depends on $(as-instr, .option arch$(comma) +m)
318 depends on !$(as-instr, .option arch$(comma) -i)
320 source "arch/riscv/Kconfig.socs"
321 source "arch/riscv/Kconfig.errata"
326 bool "Allow configurations that result in non-portable kernels"
328 RISC-V kernel binaries are compatible between all known systems
329 whenever possible, but there are some use cases that can only be
330 satisfied by configurations that result in kernel binaries that are
331 not portable between systems.
333 Selecting N does not guarantee kernels will be portable to all known
334 systems. Selecting any of the options guarded by NONPORTABLE will
335 result in kernel binaries that are unlikely to be portable between
344 This selects the base ISA that this kernel will target and must match
349 depends on NONPORTABLE
351 select GENERIC_LIB_ASHLDI3
352 select GENERIC_LIB_ASHRDI3
353 select GENERIC_LIB_LSHRDI3
354 select GENERIC_LIB_UCMPDI2
359 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
360 select SWIOTLB if MMU
364 # We must be able to map all physical memory into the kernel, but the compiler
365 # is still a bit more efficient when generating code if it's setup in a manner
366 # such that it can only map 2GiB of memory.
368 prompt "Kernel Code Model"
369 default CMODEL_MEDLOW if 32BIT
370 default CMODEL_MEDANY if 64BIT
373 bool "medium low code model"
375 bool "medium any code model"
378 config MODULE_SECTIONS
380 select HAVE_MOD_ARCH_SPECIFIC
383 bool "Symmetric Multi-Processing"
385 This enables support for systems with more than one CPU. If
386 you say N here, the kernel will run on single and
387 multiprocessor machines, but will use only one CPU of a
388 multiprocessor machine. If you say Y here, the kernel will run
389 on many, but not all, single processor machines. On a single
390 processor machine, the kernel will run faster if you say N
393 If you don't know what to do here, say N.
396 bool "Multi-core scheduler support"
399 Multi-core scheduler support improves the CPU scheduler's decision
400 making when dealing with multi-core CPU chips at a cost of slightly
401 increased overhead in some places. If unsure say N here.
404 int "Maximum number of CPUs (2-512)"
406 range 2 512 if !RISCV_SBI_V01
407 range 2 32 if RISCV_SBI_V01 && 32BIT
408 range 2 64 if RISCV_SBI_V01 && 64BIT
409 default "32" if 32BIT
410 default "64" if 64BIT
413 bool "Support for hot-pluggable CPUs"
415 select GENERIC_IRQ_MIGRATION
418 Say Y here to experiment with turning CPUs off and on. CPUs
419 can be controlled through /sys/devices/system/cpu.
421 Say N if you want to disable CPU hotplug.
432 # Common NUMA Features
434 bool "NUMA Memory Allocation and Scheduler Support"
435 depends on SMP && MMU
436 select ARCH_SUPPORTS_NUMA_BALANCING
437 select GENERIC_ARCH_NUMA
438 select HAVE_SETUP_PER_CPU_AREA
439 select NEED_PER_CPU_EMBED_FIRST_CHUNK
440 select NEED_PER_CPU_PAGE_FIRST_CHUNK
442 select USE_PERCPU_NUMA_NODE_ID
444 Enable NUMA (Non-Uniform Memory Access) support.
446 The kernel will try to allocate memory used by a CPU on the
447 local memory of the CPU and add some more NUMA awareness to the kernel.
450 int "Maximum NUMA Nodes (as a power of 2)"
455 Specify the maximum number of NUMA Nodes available on the target
456 system. Increases memory reserved to accommodate various tables.
458 config RISCV_ALTERNATIVE
460 depends on !XIP_KERNEL
462 This Kconfig allows the kernel to automatically patch the
463 erratum or cpufeature required by the execution platform at run
464 time. The code patching overhead is minimal, as it's only done
465 once at boot and once on each module load.
467 config RISCV_ALTERNATIVE_EARLY
469 depends on RISCV_ALTERNATIVE
471 Allows early patching of the kernel for special errata
474 bool "Emit compressed instructions when building Linux"
477 Adds "C" to the ISA subsets that the toolchain is allowed to emit
478 when building Linux, which results in compressed instructions in the
481 If you don't know what to do here, say Y.
483 config RISCV_ISA_SVNAPOT
484 bool "Svnapot extension support for supervisor mode NAPOT pages"
485 depends on 64BIT && MMU
486 depends on RISCV_ALTERNATIVE
489 Allow kernel to detect the Svnapot ISA-extension dynamically at boot
490 time and enable its usage.
492 The Svnapot extension is used to mark contiguous PTEs as a range
493 of contiguous virtual-to-physical translations for a naturally
494 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
495 size. When HUGETLBFS is also selected this option unconditionally
496 allocates some memory for each NAPOT page size supported by the kernel.
497 When optimizing for low memory consumption and for platforms without
498 the Svnapot extension, it may be better to say N here.
500 If you don't know what to do here, say Y.
502 config RISCV_ISA_SVPBMT
503 bool "Svpbmt extension support for supervisor mode page-based memory types"
504 depends on 64BIT && MMU
505 depends on RISCV_ALTERNATIVE
508 Adds support to dynamically detect the presence of the Svpbmt
509 ISA-extension (Supervisor-mode: page-based memory types) and
512 The memory type for a page contains a combination of attributes
513 that indicate the cacheability, idempotency, and ordering
514 properties for access to that page.
516 The Svpbmt extension is only available on 64-bit cpus.
518 If you don't know what to do here, say Y.
520 config TOOLCHAIN_HAS_V
523 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
524 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
525 depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
526 depends on AS_HAS_OPTION_ARCH
529 bool "VECTOR extension support"
530 depends on TOOLCHAIN_HAS_V
532 select DYNAMIC_SIGFRAME
535 Say N here if you want to disable all vector related procedure
538 If you don't know what to do here, say Y.
540 config RISCV_ISA_V_DEFAULT_ENABLE
541 bool "Enable userspace Vector by default"
542 depends on RISCV_ISA_V
545 Say Y here if you want to enable Vector in userspace by default.
546 Otherwise, userspace has to make explicit prctl() call to enable
547 Vector, or enable it via the sysctl interface.
549 If you don't know what to do here, say Y.
551 config RISCV_ISA_V_UCOPY_THRESHOLD
552 int "Threshold size for vectorized user copies"
553 depends on RISCV_ISA_V
556 Prefer using vectorized copy_to_user()/copy_from_user() when the
557 workload size exceeds this value.
559 config RISCV_ISA_V_PREEMPTIVE
560 bool "Run kernel-mode Vector with kernel preemption"
561 depends on PREEMPTION
562 depends on RISCV_ISA_V
565 Usually, in-kernel SIMD routines are run with preemption disabled.
566 Functions which envoke long running SIMD thus must yield core's
567 vector unit to prevent blocking other tasks for too long.
569 This config allows kernel to run SIMD without explicitly disable
570 preemption. Enabling this config will result in higher memory
571 consumption due to the allocation of per-task's kernel Vector context.
573 config TOOLCHAIN_HAS_ZBB
576 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
577 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
578 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
579 depends on AS_HAS_OPTION_ARCH
582 bool "Zbb extension support for bit manipulation instructions"
583 depends on TOOLCHAIN_HAS_ZBB
585 depends on RISCV_ALTERNATIVE
588 Adds support to dynamically detect the presence of the ZBB
589 extension (basic bit manipulation) and enable its usage.
591 The Zbb extension provides instructions to accelerate a number
592 of bit-specific operations (count bit population, sign extending,
595 If you don't know what to do here, say Y.
597 config RISCV_ISA_ZICBOM
598 bool "Zicbom extension support for non-coherent DMA operation"
600 depends on RISCV_ALTERNATIVE
602 select RISCV_DMA_NONCOHERENT
603 select DMA_DIRECT_REMAP
605 Adds support to dynamically detect the presence of the ZICBOM
606 extension (Cache Block Management Operations) and enable its
609 The Zicbom extension can be used to handle for example
610 non-coherent DMA support on devices that need it.
612 If you don't know what to do here, say Y.
614 config RISCV_ISA_ZICBOZ
615 bool "Zicboz extension support for faster zeroing of memory"
617 depends on RISCV_ALTERNATIVE
620 Enable the use of the Zicboz extension (cbo.zero instruction)
623 The Zicboz extension is used for faster zeroing of memory.
625 If you don't know what to do here, say Y.
627 config TOOLCHAIN_HAS_ZIHINTPAUSE
630 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
631 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
632 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
634 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
636 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
637 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd
638 depends on AS_IS_GNU && AS_VERSION >= 23600
640 Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer
641 20191213 version, which moves some instructions from the I extension to
642 the Zicsr and Zifencei extensions. This requires explicitly specifying
643 Zicsr and Zifencei when binutils >= 2.38 or GCC >= 12.1.0. Zicsr
644 and Zifencei are supported in binutils from version 2.36 onwards.
645 To make life easier, and avoid forcing toolchains that default to a
646 newer ISA spec to version 2.2, relax the check to binutils >= 2.36.
647 For clang < 17 or GCC < 11.3.0, for which this is not possible or need
648 special treatment, this is dealt with in TOOLCHAIN_NEEDS_OLD_ISA_SPEC.
650 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
652 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
653 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
654 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d29f5d6ab513c52fd872f532c492e35ae9fd6671
655 depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC && GCC_VERSION < 110300)
657 Certain versions of clang and GCC do not support zicsr and zifencei via
658 -march. This option causes an older ISA spec compatible with these older
659 versions of clang and GCC to be passed to GAS, which has the same result
660 as passing zicsr and zifencei to -march.
666 Say N here if you want to disable all floating-point related procedure
669 If you don't know what to do here, say Y.
672 bool "Independent irq & softirq stacks" if EXPERT
674 select HAVE_IRQ_EXIT_ON_IRQ_STACK
675 select HAVE_SOFTIRQ_ON_OWN_STACK
677 Add independent irq & softirq stacks for percpu to prevent kernel stack
678 overflows. We may save some memory footprint by disabling IRQ_STACKS.
680 config THREAD_SIZE_ORDER
681 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
683 default 1 if 32BIT && !KASAN
684 default 3 if 64BIT && KASAN
687 Specify the Pages of thread stack size (from 4KB to 64KB), which also
688 affects irq stack size, which is equal to thread stack size.
690 config RISCV_MISALIGNED
691 bool "Support misaligned load/store traps for kernel and userspace"
692 select SYSCTL_ARCH_UNALIGN_ALLOW
695 Say Y here if you want the kernel to embed support for misaligned
696 load/store for both kernel and userspace. When disable, misaligned
697 accesses will generate SIGBUS in userspace and panic in kernel.
699 config RISCV_EFFICIENT_UNALIGNED_ACCESS
700 bool "Assume the CPU supports fast unaligned memory accesses"
701 depends on NONPORTABLE
702 select DCACHE_WORD_ACCESS if MMU
703 select HAVE_EFFICIENT_UNALIGNED_ACCESS
705 Say Y here if you want the kernel to assume that the CPU supports
706 efficient unaligned memory accesses. When enabled, this option
707 improves the performance of the kernel on such CPUs. However, the
708 kernel will run much more slowly, or will not be able to run at all,
709 on CPUs that do not support efficient unaligned memory accesses.
711 If unsure what to do here, say N.
713 endmenu # "Platform type"
715 menu "Kernel features"
717 source "kernel/Kconfig.hz"
720 bool "SBI v0.1 support"
723 This config allows kernel to use SBI v0.1 APIs. This will be
724 deprecated in future once legacy M-mode software are no longer in use.
726 config RISCV_BOOT_SPINWAIT
727 bool "Spinwait booting method"
729 default y if RISCV_SBI_V01 || RISCV_M_MODE
731 This enables support for booting Linux via spinwait method. In the
732 spinwait method, all cores randomly jump to Linux. One of the cores
733 gets chosen via lottery and all other keep spinning on a percpu
734 variable. This method cannot support CPU hotplug and sparse hartid
735 scheme. It should be only enabled for M-mode Linux or platforms relying
736 on older firmware without SBI HSM extension. All other platforms should
737 rely on ordered booting via SBI HSM extension which gets chosen
738 dynamically at runtime if the firmware supports it.
740 Since spinwait is incompatible with sparse hart IDs, it requires
741 NR_CPUS be large enough to contain the physical hart ID of the first
744 If unsure what to do here, say N.
746 config ARCH_SUPPORTS_KEXEC
749 config ARCH_SELECTS_KEXEC
752 select HOTPLUG_CPU if SMP
754 config ARCH_SUPPORTS_KEXEC_FILE
757 config ARCH_SELECTS_KEXEC_FILE
759 depends on KEXEC_FILE
760 select HAVE_IMA_KEXEC if IMA
763 config ARCH_SUPPORTS_KEXEC_PURGATORY
764 def_bool ARCH_SUPPORTS_KEXEC_FILE
766 config ARCH_SUPPORTS_CRASH_DUMP
769 config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
773 bool "Kernel support for 32-bit U-mode"
775 depends on 64BIT && MMU
777 This option enables support for a 32-bit U-mode running under a 64-bit
778 kernel at S-mode. riscv32-specific components such as system calls,
779 the user helper functions (vdso), signal rt_frame functions and the
780 ptrace interface are handled appropriately by the kernel.
782 If you want to execute 32-bit userspace applications, say Y.
785 bool "Enable paravirtualization code"
788 This changes the kernel so it can modify itself when it is run
789 under a hypervisor, potentially improving performance significantly
790 over full virtualization.
792 config PARAVIRT_TIME_ACCOUNTING
793 bool "Paravirtual steal time accounting"
796 Select this option to enable fine granularity task steal time
797 accounting. Time spent executing other tasks in parallel with
798 the current vCPU is discounted from the vCPU power. To account for
799 that, there can be a small performance impact.
801 If in doubt, say N here.
804 bool "Build a relocatable kernel"
805 depends on MMU && 64BIT && !XIP_KERNEL
807 This builds a kernel as a Position Independent Executable (PIE),
808 which retains all relocation metadata required to relocate the
809 kernel binary at runtime to a different virtual address than the
810 address it was linked at.
811 Since RISCV uses the RELA relocation format, this requires a
812 relocation pass at runtime even if the kernel is loaded at the
813 same address it was linked at.
817 config RANDOMIZE_BASE
818 bool "Randomize the address of the kernel image"
820 depends on MMU && 64BIT && !XIP_KERNEL
822 Randomizes the virtual address at which the kernel image is
823 loaded, as a security feature that deters exploit attempts
824 relying on knowledge of the location of kernel internals.
826 It is the bootloader's job to provide entropy, by passing a
827 random u64 value in /chosen/kaslr-seed at kernel entry.
829 When booting via the UEFI stub, it will invoke the firmware's
830 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
831 to the kernel proper. In addition, it will randomise the physical
832 location of the kernel Image as well.
836 endmenu # "Kernel features"
841 string "Built-in kernel command line"
843 For most platforms, the arguments for the kernel's command line
844 are provided at run-time, during boot. However, there are cases
845 where either no arguments are being provided or the provided
846 arguments are insufficient or even invalid.
848 When that occurs, it is possible to define a built-in command
849 line here and choose how the kernel should use it later on.
852 prompt "Built-in command line usage" if CMDLINE != ""
853 default CMDLINE_FALLBACK
855 Choose how the kernel will handle the provided built-in command
858 config CMDLINE_FALLBACK
859 bool "Use bootloader kernel arguments if available"
861 Use the built-in command line as fallback in case we get nothing
862 during boot. This is the default behaviour.
864 config CMDLINE_EXTEND
865 bool "Extend bootloader kernel arguments"
867 The command-line arguments provided during boot will be
868 appended to the built-in command line. This is useful in
869 cases where the provided arguments are insufficient and
870 you don't want to or cannot modify them.
873 bool "Always use the default kernel command string"
875 Always use the built-in command line, even if we get one during
876 boot. This is useful in case you need to override the provided
877 command line on systems where you don't have or want control
886 bool "UEFI runtime support"
887 depends on OF && !XIP_KERNEL
890 select ARCH_SUPPORTS_ACPI if 64BIT
891 select EFI_GENERIC_STUB
892 select EFI_PARAMS_FROM_FDT
893 select EFI_RUNTIME_WRAPPERS
899 This option provides support for runtime services provided
900 by UEFI firmware (such as non-volatile variables, realtime
901 clock, and platform reset). A UEFI stub is also provided to
902 allow the kernel to be booted as an EFI application. This
903 is only useful on systems that have UEFI firmware.
905 config CC_HAVE_STACKPROTECTOR_TLS
906 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
908 config STACKPROTECTOR_PER_TASK
910 depends on !RANDSTRUCT
911 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
913 config PHYS_RAM_BASE_FIXED
914 bool "Explicitly specified physical RAM address"
915 depends on NONPORTABLE
919 hex "Platform Physical RAM address"
920 depends on PHYS_RAM_BASE_FIXED
923 This is the physical address of RAM in the system. It has to be
924 explicitly specified to run early relocations of read-write data
928 bool "Kernel Execute-In-Place from ROM"
929 depends on MMU && SPARSEMEM && NONPORTABLE
930 # This prevents XIP from being enabled by all{yes,mod}config, which
931 # fail to build since XIP doesn't support large kernels.
932 depends on !COMPILE_TEST
933 select PHYS_RAM_BASE_FIXED
935 Execute-In-Place allows the kernel to run from non-volatile storage
936 directly addressable by the CPU, such as NOR flash. This saves RAM
937 space since the text section of the kernel is not loaded from flash
938 to RAM. Read-write sections, such as the data section and stack,
939 are still copied to RAM. The XIP kernel is not compressed since
940 it has to run directly from flash, so it will take more space to
941 store it. The flash address used to link the kernel object files,
942 and for storing it, is configuration dependent. Therefore, if you
943 say Y here, you must know the proper physical address where to
944 store the kernel image depending on your own flash memory usage.
946 Also note that the make target becomes "make xipImage" rather than
947 "make zImage" or "make Image". The final kernel binary to put in
948 ROM memory will be arch/riscv/boot/xipImage.
950 SPARSEMEM is required because the kernel text and rodata that are
951 flash resident are not backed by memmap, then any attempt to get
952 a struct page on those regions will trigger a fault.
957 hex "XIP Kernel Physical Location"
958 depends on XIP_KERNEL
961 This is the physical address in your flash memory the kernel will
962 be linked for and stored to. This address is dependent on your
965 config RISCV_ISA_FALLBACK
966 bool "Permit falling back to parsing riscv,isa for extension support by default"
969 Parsing the "riscv,isa" devicetree property has been deprecated and
970 replaced by a list of explicitly defined strings. For compatibility
971 with existing platforms, the kernel will fall back to parsing the
972 "riscv,isa" property if the replacements are not found.
974 Selecting N here will result in a kernel that does not use the
975 fallback, unless the commandline "riscv_isa_fallback" parameter is
978 Please see the dt-binding, located at
979 Documentation/devicetree/bindings/riscv/extensions.yaml for details
980 on the replacement properties, "riscv,isa-base" and
981 "riscv,isa-extensions".
984 bool "Built-in device tree"
985 depends on OF && NONPORTABLE
986 default y if XIP_KERNEL
988 endmenu # "Boot options"
997 config ARCH_PROC_KCORE_TEXT
1000 menu "Power management options"
1002 source "kernel/power/Kconfig"
1004 # Hibernation is only possible on systems where the SBI implementation has
1005 # marked its reserved memory as not accessible from, or does not run
1006 # from the same memory as, Linux
1007 config ARCH_HIBERNATION_POSSIBLE
1008 def_bool NONPORTABLE
1010 config ARCH_HIBERNATION_HEADER
1011 def_bool HIBERNATION
1013 config ARCH_SUSPEND_POSSIBLE
1016 endmenu # "Power management options"
1018 menu "CPU Power Management"
1020 source "drivers/cpuidle/Kconfig"
1022 source "drivers/cpufreq/Kconfig"
1024 endmenu # "CPU Power Management"
1026 source "arch/riscv/kvm/Kconfig"
1028 source "drivers/acpi/Kconfig"