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_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
57 select ARCH_WANT_FRAME_POINTERS
58 select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
59 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
60 select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
61 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
62 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
63 select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
64 select BUILDTIME_TABLE_SORT if MMU
65 select CLINT_TIMER if !MMU
66 select CLONE_BACKWARDS
68 select CPU_PM if CPU_IDLE || HIBERNATION
70 select FRAME_POINTER if PERF_EVENTS || (FUNCTION_TRACER && !DYNAMIC_FTRACE)
71 select GENERIC_ARCH_TOPOLOGY
72 select GENERIC_ATOMIC64 if !64BIT
73 select GENERIC_CLOCKEVENTS_BROADCAST if SMP
74 select GENERIC_EARLY_IOREMAP
76 select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
77 select GENERIC_IDLE_POLL_SETUP
78 select GENERIC_IOREMAP if MMU
79 select GENERIC_IRQ_IPI if SMP
80 select GENERIC_IRQ_IPI_MUX if SMP
81 select GENERIC_IRQ_MULTI_HANDLER
82 select GENERIC_IRQ_SHOW
83 select GENERIC_IRQ_SHOW_LEVEL
84 select GENERIC_LIB_DEVMEM_IS_ALLOWED
85 select GENERIC_PCI_IOMAP
86 select GENERIC_PTDUMP if MMU
87 select GENERIC_SCHED_CLOCK
88 select GENERIC_SMP_IDLE_THREAD
89 select GENERIC_TIME_VSYSCALL if MMU && 64BIT
90 select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
91 select HARDIRQS_SW_RESEND
92 select HAS_IOPORT if MMU
93 select HAVE_ARCH_AUDITSYSCALL
94 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
95 select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT && !XIP_KERNEL
96 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
97 select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
98 select HAVE_ARCH_KASAN if MMU && 64BIT
99 select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
100 select HAVE_ARCH_KFENCE if MMU && 64BIT
101 select HAVE_ARCH_KGDB if !XIP_KERNEL
102 select HAVE_ARCH_KGDB_QXFER_PKT
103 select HAVE_ARCH_MMAP_RND_BITS if MMU
104 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
105 select HAVE_ARCH_SECCOMP_FILTER
106 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
107 select HAVE_ARCH_TRACEHOOK
108 select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
109 select HAVE_ARCH_USERFAULTFD_MINOR if 64BIT && USERFAULTFD
110 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT
111 select HAVE_ASM_MODVERSIONS
112 select HAVE_CONTEXT_TRACKING_USER
113 select HAVE_DEBUG_KMEMLEAK
114 select HAVE_DMA_CONTIGUOUS if MMU
115 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
116 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
117 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
118 select HAVE_FUNCTION_GRAPH_TRACER
119 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
120 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
121 select HAVE_EBPF_JIT if MMU
122 select HAVE_FUNCTION_ARG_ACCESS_API
123 select HAVE_FUNCTION_ERROR_INJECTION
124 select HAVE_GCC_PLUGINS
125 select HAVE_GENERIC_VDSO if MMU && 64BIT
126 select HAVE_IRQ_TIME_ACCOUNTING
127 select HAVE_KPROBES if !XIP_KERNEL
128 select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
129 select HAVE_KRETPROBES if !XIP_KERNEL
130 # https://github.com/ClangBuiltLinux/linux/issues/1881
131 select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD
135 select HAVE_PERF_EVENTS
136 select HAVE_PERF_REGS
137 select HAVE_PERF_USER_STACK_DUMP
138 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
139 select HAVE_PREEMPT_DYNAMIC_KEY if !XIP_KERNEL
140 select HAVE_REGS_AND_STACK_ACCESS_API
141 select HAVE_RETHOOK if !XIP_KERNEL
143 select HAVE_STACKPROTECTOR
144 select HAVE_SYSCALL_TRACEPOINTS
145 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
147 select IRQ_FORCED_THREADING
148 select KASAN_VMALLOC if KASAN
149 select LOCK_MM_AND_FIND_VMA
150 select MODULES_USE_ELF_RELA if MODULES
151 select MODULE_SECTIONS if MODULES
153 select OF_EARLY_FLATTREE
155 select PCI_DOMAINS_GENERIC if PCI
156 select PCI_MSI if PCI
157 select RISCV_ALTERNATIVE if !XIP_KERNEL
159 select RISCV_TIMER if RISCV_SBI
162 select SYSCTL_EXCEPTION_TRACE
163 select THREAD_INFO_IN_TASK
164 select TRACE_IRQFLAGS_SUPPORT
165 select UACCESS_MEMCPY if !MMU
166 select ZONE_DMA32 if 64BIT
168 config CLANG_SUPPORTS_DYNAMIC_FTRACE
170 # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e
171 depends on CLANG_VERSION >= 130000
172 # https://github.com/ClangBuiltLinux/linux/issues/1817
173 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
175 config GCC_SUPPORTS_DYNAMIC_FTRACE
177 depends on $(cc-option,-fpatchable-function-entry=8)
179 config HAVE_SHADOW_CALL_STACK
180 def_bool $(cc-option,-fsanitize=shadow-call-stack)
181 # https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/a484e843e6eeb51f0cb7b8819e50da6d2444d769
182 depends on $(ld-option,--no-relax-gp)
184 config ARCH_MMAP_RND_BITS_MIN
188 config ARCH_MMAP_RND_COMPAT_BITS_MIN
191 # max bits determined by the following formula:
192 # VA_BITS - PAGE_SHIFT - 3
193 config ARCH_MMAP_RND_BITS_MAX
194 default 24 if 64BIT # SV39 based
197 config ARCH_MMAP_RND_COMPAT_BITS_MAX
200 # set if we run in machine mode, cleared if we run in supervisor mode
205 # set if we are running in S-mode and can use SBI calls
208 depends on !RISCV_M_MODE
212 bool "MMU-based Paged Memory Management Support"
215 Select if you want MMU-based virtualised addressing space
216 support by paged memory management. If unsure, say 'Y'.
220 default 0xC0000000 if 32BIT && MMU
221 default 0x80000000 if !MMU
222 default 0xff60000000000000 if 64BIT
224 config KASAN_SHADOW_OFFSET
226 depends on KASAN_GENERIC
227 default 0xdfffffff00000000 if 64BIT
228 default 0xffffffff if 32BIT
230 config ARCH_FLATMEM_ENABLE
233 config ARCH_SPARSEMEM_ENABLE
236 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
237 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
239 config ARCH_SELECT_MEMORY_MODEL
240 def_bool ARCH_SPARSEMEM_ENABLE
242 config ARCH_SUPPORTS_UPROBES
245 config STACKTRACE_SUPPORT
251 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
253 config GENERIC_BUG_RELATIVE_POINTERS
256 config GENERIC_CALIBRATE_DELAY
262 config GENERIC_HWEIGHT
265 config FIX_EARLYCON_MEM
268 config PGTABLE_LEVELS
273 config LOCKDEP_SUPPORT
276 config RISCV_DMA_NONCOHERENT
278 select ARCH_HAS_DMA_PREP_COHERENT
279 select ARCH_HAS_SETUP_DMA_OPS
280 select ARCH_HAS_SYNC_DMA_FOR_CPU
281 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
282 select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB
283 select DMA_DIRECT_REMAP if MMU
285 config RISCV_NONSTANDARD_CACHE_OPS
287 depends on RISCV_DMA_NONCOHERENT
289 This enables function pointer support for non-standard noncoherent
290 systems to handle cache management.
293 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
295 config AS_HAS_OPTION_ARCH
296 # https://reviews.llvm.org/D123515
298 depends on $(as-instr, .option arch$(comma) +m)
299 depends on !$(as-instr, .option arch$(comma) -i)
301 source "arch/riscv/Kconfig.socs"
302 source "arch/riscv/Kconfig.errata"
307 bool "Allow configurations that result in non-portable kernels"
309 RISC-V kernel binaries are compatible between all known systems
310 whenever possible, but there are some use cases that can only be
311 satisfied by configurations that result in kernel binaries that are
312 not portable between systems.
314 Selecting N does not guarantee kernels will be portable to all known
315 systems. Selecting any of the options guarded by NONPORTABLE will
316 result in kernel binaries that are unlikely to be portable between
325 This selects the base ISA that this kernel will target and must match
330 depends on NONPORTABLE
332 select GENERIC_LIB_ASHLDI3
333 select GENERIC_LIB_ASHRDI3
334 select GENERIC_LIB_LSHRDI3
335 select GENERIC_LIB_UCMPDI2
340 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
341 select SWIOTLB if MMU
345 # We must be able to map all physical memory into the kernel, but the compiler
346 # is still a bit more efficient when generating code if it's setup in a manner
347 # such that it can only map 2GiB of memory.
349 prompt "Kernel Code Model"
350 default CMODEL_MEDLOW if 32BIT
351 default CMODEL_MEDANY if 64BIT
354 bool "medium low code model"
356 bool "medium any code model"
359 config MODULE_SECTIONS
361 select HAVE_MOD_ARCH_SPECIFIC
364 bool "Symmetric Multi-Processing"
366 This enables support for systems with more than one CPU. If
367 you say N here, the kernel will run on single and
368 multiprocessor machines, but will use only one CPU of a
369 multiprocessor machine. If you say Y here, the kernel will run
370 on many, but not all, single processor machines. On a single
371 processor machine, the kernel will run faster if you say N
374 If you don't know what to do here, say N.
377 bool "Multi-core scheduler support"
380 Multi-core scheduler support improves the CPU scheduler's decision
381 making when dealing with multi-core CPU chips at a cost of slightly
382 increased overhead in some places. If unsure say N here.
385 int "Maximum number of CPUs (2-512)"
387 range 2 512 if !RISCV_SBI_V01
388 range 2 32 if RISCV_SBI_V01 && 32BIT
389 range 2 64 if RISCV_SBI_V01 && 64BIT
390 default "32" if 32BIT
391 default "64" if 64BIT
394 bool "Support for hot-pluggable CPUs"
396 select GENERIC_IRQ_MIGRATION
399 Say Y here to experiment with turning CPUs off and on. CPUs
400 can be controlled through /sys/devices/system/cpu.
402 Say N if you want to disable CPU hotplug.
413 # Common NUMA Features
415 bool "NUMA Memory Allocation and Scheduler Support"
416 depends on SMP && MMU
417 select ARCH_SUPPORTS_NUMA_BALANCING
418 select GENERIC_ARCH_NUMA
419 select NEED_PER_CPU_EMBED_FIRST_CHUNK
421 select USE_PERCPU_NUMA_NODE_ID
423 Enable NUMA (Non-Uniform Memory Access) support.
425 The kernel will try to allocate memory used by a CPU on the
426 local memory of the CPU and add some more NUMA awareness to the kernel.
429 int "Maximum NUMA Nodes (as a power of 2)"
434 Specify the maximum number of NUMA Nodes available on the target
435 system. Increases memory reserved to accommodate various tables.
437 config RISCV_ALTERNATIVE
439 depends on !XIP_KERNEL
441 This Kconfig allows the kernel to automatically patch the
442 erratum or cpufeature required by the execution platform at run
443 time. The code patching overhead is minimal, as it's only done
444 once at boot and once on each module load.
446 config RISCV_ALTERNATIVE_EARLY
448 depends on RISCV_ALTERNATIVE
450 Allows early patching of the kernel for special errata
453 bool "Emit compressed instructions when building Linux"
456 Adds "C" to the ISA subsets that the toolchain is allowed to emit
457 when building Linux, which results in compressed instructions in the
460 If you don't know what to do here, say Y.
462 config RISCV_ISA_SVNAPOT
463 bool "Svnapot extension support for supervisor mode NAPOT pages"
464 depends on 64BIT && MMU
465 depends on RISCV_ALTERNATIVE
468 Allow kernel to detect the Svnapot ISA-extension dynamically at boot
469 time and enable its usage.
471 The Svnapot extension is used to mark contiguous PTEs as a range
472 of contiguous virtual-to-physical translations for a naturally
473 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
474 size. When HUGETLBFS is also selected this option unconditionally
475 allocates some memory for each NAPOT page size supported by the kernel.
476 When optimizing for low memory consumption and for platforms without
477 the Svnapot extension, it may be better to say N here.
479 If you don't know what to do here, say Y.
481 config RISCV_ISA_SVPBMT
482 bool "Svpbmt extension support for supervisor mode page-based memory types"
483 depends on 64BIT && MMU
484 depends on RISCV_ALTERNATIVE
487 Adds support to dynamically detect the presence of the Svpbmt
488 ISA-extension (Supervisor-mode: page-based memory types) and
491 The memory type for a page contains a combination of attributes
492 that indicate the cacheability, idempotency, and ordering
493 properties for access to that page.
495 The Svpbmt extension is only available on 64-bit cpus.
497 If you don't know what to do here, say Y.
499 config TOOLCHAIN_HAS_V
502 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
503 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
504 depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
505 depends on AS_HAS_OPTION_ARCH
508 bool "VECTOR extension support"
509 depends on TOOLCHAIN_HAS_V
511 select DYNAMIC_SIGFRAME
514 Say N here if you want to disable all vector related procedure
517 If you don't know what to do here, say Y.
519 config RISCV_ISA_V_DEFAULT_ENABLE
520 bool "Enable userspace Vector by default"
521 depends on RISCV_ISA_V
524 Say Y here if you want to enable Vector in userspace by default.
525 Otherwise, userspace has to make explicit prctl() call to enable
526 Vector, or enable it via the sysctl interface.
528 If you don't know what to do here, say Y.
530 config TOOLCHAIN_HAS_ZBB
533 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
534 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
535 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
536 depends on AS_HAS_OPTION_ARCH
539 bool "Zbb extension support for bit manipulation instructions"
540 depends on TOOLCHAIN_HAS_ZBB
542 depends on RISCV_ALTERNATIVE
545 Adds support to dynamically detect the presence of the ZBB
546 extension (basic bit manipulation) and enable its usage.
548 The Zbb extension provides instructions to accelerate a number
549 of bit-specific operations (count bit population, sign extending,
552 If you don't know what to do here, say Y.
554 config RISCV_ISA_ZICBOM
555 bool "Zicbom extension support for non-coherent DMA operation"
557 depends on RISCV_ALTERNATIVE
559 select RISCV_DMA_NONCOHERENT
561 Adds support to dynamically detect the presence of the ZICBOM
562 extension (Cache Block Management Operations) and enable its
565 The Zicbom extension can be used to handle for example
566 non-coherent DMA support on devices that need it.
568 If you don't know what to do here, say Y.
570 config RISCV_ISA_ZICBOZ
571 bool "Zicboz extension support for faster zeroing of memory"
573 depends on RISCV_ALTERNATIVE
576 Enable the use of the Zicboz extension (cbo.zero instruction)
579 The Zicboz extension is used for faster zeroing of memory.
581 If you don't know what to do here, say Y.
583 config TOOLCHAIN_HAS_ZIHINTPAUSE
586 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
587 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
588 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
590 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
592 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
593 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd
594 depends on AS_IS_GNU && AS_VERSION >= 23600
596 Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer
597 20191213 version, which moves some instructions from the I extension to
598 the Zicsr and Zifencei extensions. This requires explicitly specifying
599 Zicsr and Zifencei when binutils >= 2.38 or GCC >= 12.1.0. Zicsr
600 and Zifencei are supported in binutils from version 2.36 onwards.
601 To make life easier, and avoid forcing toolchains that default to a
602 newer ISA spec to version 2.2, relax the check to binutils >= 2.36.
603 For clang < 17 or GCC < 11.3.0, for which this is not possible or need
604 special treatment, this is dealt with in TOOLCHAIN_NEEDS_OLD_ISA_SPEC.
606 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
608 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
609 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
610 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d29f5d6ab513c52fd872f532c492e35ae9fd6671
611 depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC && GCC_VERSION < 110300)
613 Certain versions of clang and GCC do not support zicsr and zifencei via
614 -march. This option causes an older ISA spec compatible with these older
615 versions of clang and GCC to be passed to GAS, which has the same result
616 as passing zicsr and zifencei to -march.
622 Say N here if you want to disable all floating-point related procedure
625 If you don't know what to do here, say Y.
628 bool "Independent irq & softirq stacks" if EXPERT
630 select HAVE_IRQ_EXIT_ON_IRQ_STACK
631 select HAVE_SOFTIRQ_ON_OWN_STACK
633 Add independent irq & softirq stacks for percpu to prevent kernel stack
634 overflows. We may save some memory footprint by disabling IRQ_STACKS.
636 config THREAD_SIZE_ORDER
637 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
639 default 1 if 32BIT && !KASAN
640 default 3 if 64BIT && KASAN
643 Specify the Pages of thread stack size (from 4KB to 64KB), which also
644 affects irq stack size, which is equal to thread stack size.
646 config RISCV_MISALIGNED
647 bool "Support misaligned load/store traps for kernel and userspace"
648 select SYSCTL_ARCH_UNALIGN_ALLOW
651 Say Y here if you want the kernel to embed support for misaligned
652 load/store for both kernel and userspace. When disable, misaligned
653 accesses will generate SIGBUS in userspace and panic in kernel.
655 endmenu # "Platform type"
657 menu "Kernel features"
659 source "kernel/Kconfig.hz"
662 bool "SBI v0.1 support"
665 This config allows kernel to use SBI v0.1 APIs. This will be
666 deprecated in future once legacy M-mode software are no longer in use.
668 config RISCV_BOOT_SPINWAIT
669 bool "Spinwait booting method"
671 default y if RISCV_SBI_V01 || RISCV_M_MODE
673 This enables support for booting Linux via spinwait method. In the
674 spinwait method, all cores randomly jump to Linux. One of the cores
675 gets chosen via lottery and all other keep spinning on a percpu
676 variable. This method cannot support CPU hotplug and sparse hartid
677 scheme. It should be only enabled for M-mode Linux or platforms relying
678 on older firmware without SBI HSM extension. All other platforms should
679 rely on ordered booting via SBI HSM extension which gets chosen
680 dynamically at runtime if the firmware supports it.
682 Since spinwait is incompatible with sparse hart IDs, it requires
683 NR_CPUS be large enough to contain the physical hart ID of the first
686 If unsure what to do here, say N.
688 config ARCH_SUPPORTS_KEXEC
691 config ARCH_SELECTS_KEXEC
694 select HOTPLUG_CPU if SMP
696 config ARCH_SUPPORTS_KEXEC_FILE
697 def_bool 64BIT && MMU
699 config ARCH_SELECTS_KEXEC_FILE
701 depends on KEXEC_FILE
702 select HAVE_IMA_KEXEC if IMA
705 config ARCH_SUPPORTS_KEXEC_PURGATORY
708 depends on CRYPTO_SHA256=y
710 config ARCH_SUPPORTS_CRASH_DUMP
714 bool "Kernel support for 32-bit U-mode"
716 depends on 64BIT && MMU
718 This option enables support for a 32-bit U-mode running under a 64-bit
719 kernel at S-mode. riscv32-specific components such as system calls,
720 the user helper functions (vdso), signal rt_frame functions and the
721 ptrace interface are handled appropriately by the kernel.
723 If you want to execute 32-bit userspace applications, say Y.
726 bool "Build a relocatable kernel"
727 depends on MMU && 64BIT && !XIP_KERNEL
729 This builds a kernel as a Position Independent Executable (PIE),
730 which retains all relocation metadata required to relocate the
731 kernel binary at runtime to a different virtual address than the
732 address it was linked at.
733 Since RISCV uses the RELA relocation format, this requires a
734 relocation pass at runtime even if the kernel is loaded at the
735 same address it was linked at.
739 config RANDOMIZE_BASE
740 bool "Randomize the address of the kernel image"
742 depends on MMU && 64BIT && !XIP_KERNEL
744 Randomizes the virtual address at which the kernel image is
745 loaded, as a security feature that deters exploit attempts
746 relying on knowledge of the location of kernel internals.
748 It is the bootloader's job to provide entropy, by passing a
749 random u64 value in /chosen/kaslr-seed at kernel entry.
751 When booting via the UEFI stub, it will invoke the firmware's
752 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
753 to the kernel proper. In addition, it will randomise the physical
754 location of the kernel Image as well.
758 endmenu # "Kernel features"
763 string "Built-in kernel command line"
765 For most platforms, the arguments for the kernel's command line
766 are provided at run-time, during boot. However, there are cases
767 where either no arguments are being provided or the provided
768 arguments are insufficient or even invalid.
770 When that occurs, it is possible to define a built-in command
771 line here and choose how the kernel should use it later on.
774 prompt "Built-in command line usage" if CMDLINE != ""
775 default CMDLINE_FALLBACK
777 Choose how the kernel will handle the provided built-in command
780 config CMDLINE_FALLBACK
781 bool "Use bootloader kernel arguments if available"
783 Use the built-in command line as fallback in case we get nothing
784 during boot. This is the default behaviour.
786 config CMDLINE_EXTEND
787 bool "Extend bootloader kernel arguments"
789 The command-line arguments provided during boot will be
790 appended to the built-in command line. This is useful in
791 cases where the provided arguments are insufficient and
792 you don't want to or cannot modify them.
795 bool "Always use the default kernel command string"
797 Always use the built-in command line, even if we get one during
798 boot. This is useful in case you need to override the provided
799 command line on systems where you don't have or want control
808 bool "UEFI runtime support"
809 depends on OF && !XIP_KERNEL
812 select ARCH_SUPPORTS_ACPI if 64BIT
813 select EFI_GENERIC_STUB
814 select EFI_PARAMS_FROM_FDT
815 select EFI_RUNTIME_WRAPPERS
821 This option provides support for runtime services provided
822 by UEFI firmware (such as non-volatile variables, realtime
823 clock, and platform reset). A UEFI stub is also provided to
824 allow the kernel to be booted as an EFI application. This
825 is only useful on systems that have UEFI firmware.
827 config CC_HAVE_STACKPROTECTOR_TLS
828 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
830 config STACKPROTECTOR_PER_TASK
832 depends on !RANDSTRUCT
833 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
835 config PHYS_RAM_BASE_FIXED
836 bool "Explicitly specified physical RAM address"
837 depends on NONPORTABLE
841 hex "Platform Physical RAM address"
842 depends on PHYS_RAM_BASE_FIXED
845 This is the physical address of RAM in the system. It has to be
846 explicitly specified to run early relocations of read-write data
850 bool "Kernel Execute-In-Place from ROM"
851 depends on MMU && SPARSEMEM && NONPORTABLE
852 # This prevents XIP from being enabled by all{yes,mod}config, which
853 # fail to build since XIP doesn't support large kernels.
854 depends on !COMPILE_TEST
855 select PHYS_RAM_BASE_FIXED
857 Execute-In-Place allows the kernel to run from non-volatile storage
858 directly addressable by the CPU, such as NOR flash. This saves RAM
859 space since the text section of the kernel is not loaded from flash
860 to RAM. Read-write sections, such as the data section and stack,
861 are still copied to RAM. The XIP kernel is not compressed since
862 it has to run directly from flash, so it will take more space to
863 store it. The flash address used to link the kernel object files,
864 and for storing it, is configuration dependent. Therefore, if you
865 say Y here, you must know the proper physical address where to
866 store the kernel image depending on your own flash memory usage.
868 Also note that the make target becomes "make xipImage" rather than
869 "make zImage" or "make Image". The final kernel binary to put in
870 ROM memory will be arch/riscv/boot/xipImage.
872 SPARSEMEM is required because the kernel text and rodata that are
873 flash resident are not backed by memmap, then any attempt to get
874 a struct page on those regions will trigger a fault.
879 hex "XIP Kernel Physical Location"
880 depends on XIP_KERNEL
883 This is the physical address in your flash memory the kernel will
884 be linked for and stored to. This address is dependent on your
887 config RISCV_ISA_FALLBACK
888 bool "Permit falling back to parsing riscv,isa for extension support by default"
891 Parsing the "riscv,isa" devicetree property has been deprecated and
892 replaced by a list of explicitly defined strings. For compatibility
893 with existing platforms, the kernel will fall back to parsing the
894 "riscv,isa" property if the replacements are not found.
896 Selecting N here will result in a kernel that does not use the
897 fallback, unless the commandline "riscv_isa_fallback" parameter is
900 Please see the dt-binding, located at
901 Documentation/devicetree/bindings/riscv/extensions.yaml for details
902 on the replacement properties, "riscv,isa-base" and
903 "riscv,isa-extensions".
905 endmenu # "Boot options"
909 depends on OF && NONPORTABLE
910 default y if XIP_KERNEL
919 menu "Power management options"
921 source "kernel/power/Kconfig"
923 # Hibernation is only possible on systems where the SBI implementation has
924 # marked its reserved memory as not accessible from, or does not run
925 # from the same memory as, Linux
926 config ARCH_HIBERNATION_POSSIBLE
929 config ARCH_HIBERNATION_HEADER
932 config ARCH_SUSPEND_POSSIBLE
935 endmenu # "Power management options"
937 menu "CPU Power Management"
939 source "drivers/cpuidle/Kconfig"
941 source "drivers/cpufreq/Kconfig"
943 endmenu # "CPU Power Management"
945 source "arch/riscv/kvm/Kconfig"
947 source "drivers/acpi/Kconfig"