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_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
43 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
45 select ARCH_SUPPORTS_ATOMIC_RMW
46 select ARCH_SUPPORTS_CFI_CLANG
47 select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
48 select ARCH_SUPPORTS_HUGETLBFS if MMU
49 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
50 select ARCH_SUPPORTS_PER_VMA_LOCK if MMU
51 select ARCH_USE_MEMTEST
52 select ARCH_USE_QUEUED_RWLOCKS
53 select ARCH_USES_CFI_TRAPS if CFI_CLANG
54 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
55 select ARCH_WANT_FRAME_POINTERS
56 select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
57 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
58 select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
59 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
60 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
61 select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
62 select BUILDTIME_TABLE_SORT if MMU
63 select CLINT_TIMER if !MMU
64 select CLONE_BACKWARDS
66 select CPU_PM if CPU_IDLE || HIBERNATION
68 select FRAME_POINTER if PERF_EVENTS || (FUNCTION_TRACER && !DYNAMIC_FTRACE)
69 select GENERIC_ARCH_TOPOLOGY
70 select GENERIC_ATOMIC64 if !64BIT
71 select GENERIC_CLOCKEVENTS_BROADCAST if SMP
72 select GENERIC_EARLY_IOREMAP
74 select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
75 select GENERIC_IDLE_POLL_SETUP
76 select GENERIC_IOREMAP if MMU
77 select GENERIC_IRQ_IPI if SMP
78 select GENERIC_IRQ_IPI_MUX if SMP
79 select GENERIC_IRQ_MULTI_HANDLER
80 select GENERIC_IRQ_SHOW
81 select GENERIC_IRQ_SHOW_LEVEL
82 select GENERIC_LIB_DEVMEM_IS_ALLOWED
83 select GENERIC_PCI_IOMAP
84 select GENERIC_PTDUMP if MMU
85 select GENERIC_SCHED_CLOCK
86 select GENERIC_SMP_IDLE_THREAD
87 select GENERIC_TIME_VSYSCALL if MMU && 64BIT
88 select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
89 select HARDIRQS_SW_RESEND
90 select HAS_IOPORT if MMU
91 select HAVE_ARCH_AUDITSYSCALL
92 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
93 select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT && !XIP_KERNEL
94 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
95 select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
96 select HAVE_ARCH_KASAN if MMU && 64BIT
97 select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
98 select HAVE_ARCH_KFENCE if MMU && 64BIT
99 select HAVE_ARCH_KGDB if !XIP_KERNEL
100 select HAVE_ARCH_KGDB_QXFER_PKT
101 select HAVE_ARCH_MMAP_RND_BITS if MMU
102 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
103 select HAVE_ARCH_SECCOMP_FILTER
104 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
105 select HAVE_ARCH_TRACEHOOK
106 select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
107 select HAVE_ARCH_USERFAULTFD_MINOR if 64BIT && USERFAULTFD
108 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT
109 select HAVE_ASM_MODVERSIONS
110 select HAVE_CONTEXT_TRACKING_USER
111 select HAVE_DEBUG_KMEMLEAK
112 select HAVE_DMA_CONTIGUOUS if MMU
113 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
114 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
115 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
116 select HAVE_FUNCTION_GRAPH_TRACER
117 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
118 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
119 select HAVE_EBPF_JIT if MMU
120 select HAVE_FUNCTION_ARG_ACCESS_API
121 select HAVE_FUNCTION_ERROR_INJECTION
122 select HAVE_GCC_PLUGINS
123 select HAVE_GENERIC_VDSO if MMU && 64BIT
124 select HAVE_IRQ_TIME_ACCOUNTING
125 select HAVE_KPROBES if !XIP_KERNEL
126 select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
127 select HAVE_KRETPROBES if !XIP_KERNEL
128 # https://github.com/ClangBuiltLinux/linux/issues/1881
129 select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD
133 select HAVE_PERF_EVENTS
134 select HAVE_PERF_REGS
135 select HAVE_PERF_USER_STACK_DUMP
136 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
137 select HAVE_PREEMPT_DYNAMIC_KEY if !XIP_KERNEL
138 select HAVE_REGS_AND_STACK_ACCESS_API
139 select HAVE_RETHOOK if !XIP_KERNEL
141 select HAVE_STACKPROTECTOR
142 select HAVE_SYSCALL_TRACEPOINTS
143 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
145 select IRQ_FORCED_THREADING
146 select KASAN_VMALLOC if KASAN
147 select LOCK_MM_AND_FIND_VMA
148 select MODULES_USE_ELF_RELA if MODULES
149 select MODULE_SECTIONS if MODULES
151 select OF_EARLY_FLATTREE
153 select PCI_DOMAINS_GENERIC if PCI
154 select PCI_MSI if PCI
155 select RISCV_ALTERNATIVE if !XIP_KERNEL
157 select RISCV_TIMER if RISCV_SBI
160 select SYSCTL_EXCEPTION_TRACE
161 select THREAD_INFO_IN_TASK
162 select TRACE_IRQFLAGS_SUPPORT
163 select UACCESS_MEMCPY if !MMU
164 select ZONE_DMA32 if 64BIT
166 config CLANG_SUPPORTS_DYNAMIC_FTRACE
168 # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e
169 depends on CLANG_VERSION >= 130000
170 # https://github.com/ClangBuiltLinux/linux/issues/1817
171 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
173 config GCC_SUPPORTS_DYNAMIC_FTRACE
175 depends on $(cc-option,-fpatchable-function-entry=8)
177 config ARCH_MMAP_RND_BITS_MIN
181 config ARCH_MMAP_RND_COMPAT_BITS_MIN
184 # max bits determined by the following formula:
185 # VA_BITS - PAGE_SHIFT - 3
186 config ARCH_MMAP_RND_BITS_MAX
187 default 24 if 64BIT # SV39 based
190 config ARCH_MMAP_RND_COMPAT_BITS_MAX
193 # set if we run in machine mode, cleared if we run in supervisor mode
198 # set if we are running in S-mode and can use SBI calls
201 depends on !RISCV_M_MODE
205 bool "MMU-based Paged Memory Management Support"
208 Select if you want MMU-based virtualised addressing space
209 support by paged memory management. If unsure, say 'Y'.
213 default 0xC0000000 if 32BIT && MMU
214 default 0x80000000 if !MMU
215 default 0xff60000000000000 if 64BIT
217 config KASAN_SHADOW_OFFSET
219 depends on KASAN_GENERIC
220 default 0xdfffffff00000000 if 64BIT
221 default 0xffffffff if 32BIT
223 config ARCH_FLATMEM_ENABLE
226 config ARCH_SPARSEMEM_ENABLE
229 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
230 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
232 config ARCH_SELECT_MEMORY_MODEL
233 def_bool ARCH_SPARSEMEM_ENABLE
235 config ARCH_SUPPORTS_UPROBES
238 config STACKTRACE_SUPPORT
244 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
246 config GENERIC_BUG_RELATIVE_POINTERS
249 config GENERIC_CALIBRATE_DELAY
255 config GENERIC_HWEIGHT
258 config FIX_EARLYCON_MEM
261 config PGTABLE_LEVELS
266 config LOCKDEP_SUPPORT
269 config RISCV_DMA_NONCOHERENT
271 select ARCH_HAS_DMA_PREP_COHERENT
272 select ARCH_HAS_SETUP_DMA_OPS
273 select ARCH_HAS_SYNC_DMA_FOR_CPU
274 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
275 select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB
276 select DMA_DIRECT_REMAP if MMU
278 config RISCV_NONSTANDARD_CACHE_OPS
280 depends on RISCV_DMA_NONCOHERENT
282 This enables function pointer support for non-standard noncoherent
283 systems to handle cache management.
286 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
288 config AS_HAS_OPTION_ARCH
289 # https://reviews.llvm.org/D123515
291 depends on $(as-instr, .option arch$(comma) +m)
292 depends on !$(as-instr, .option arch$(comma) -i)
294 source "arch/riscv/Kconfig.socs"
295 source "arch/riscv/Kconfig.errata"
300 bool "Allow configurations that result in non-portable kernels"
302 RISC-V kernel binaries are compatible between all known systems
303 whenever possible, but there are some use cases that can only be
304 satisfied by configurations that result in kernel binaries that are
305 not portable between systems.
307 Selecting N does not guarantee kernels will be portable to all known
308 systems. Selecting any of the options guarded by NONPORTABLE will
309 result in kernel binaries that are unlikely to be portable between
318 This selects the base ISA that this kernel will target and must match
323 depends on NONPORTABLE
325 select GENERIC_LIB_ASHLDI3
326 select GENERIC_LIB_ASHRDI3
327 select GENERIC_LIB_LSHRDI3
328 select GENERIC_LIB_UCMPDI2
333 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
334 select SWIOTLB if MMU
338 # We must be able to map all physical memory into the kernel, but the compiler
339 # is still a bit more efficient when generating code if it's setup in a manner
340 # such that it can only map 2GiB of memory.
342 prompt "Kernel Code Model"
343 default CMODEL_MEDLOW if 32BIT
344 default CMODEL_MEDANY if 64BIT
347 bool "medium low code model"
349 bool "medium any code model"
352 config MODULE_SECTIONS
354 select HAVE_MOD_ARCH_SPECIFIC
357 bool "Symmetric Multi-Processing"
359 This enables support for systems with more than one CPU. If
360 you say N here, the kernel will run on single and
361 multiprocessor machines, but will use only one CPU of a
362 multiprocessor machine. If you say Y here, the kernel will run
363 on many, but not all, single processor machines. On a single
364 processor machine, the kernel will run faster if you say N
367 If you don't know what to do here, say N.
370 bool "Multi-core scheduler support"
373 Multi-core scheduler support improves the CPU scheduler's decision
374 making when dealing with multi-core CPU chips at a cost of slightly
375 increased overhead in some places. If unsure say N here.
378 int "Maximum number of CPUs (2-512)"
380 range 2 512 if !RISCV_SBI_V01
381 range 2 32 if RISCV_SBI_V01 && 32BIT
382 range 2 64 if RISCV_SBI_V01 && 64BIT
383 default "32" if 32BIT
384 default "64" if 64BIT
387 bool "Support for hot-pluggable CPUs"
389 select GENERIC_IRQ_MIGRATION
392 Say Y here to experiment with turning CPUs off and on. CPUs
393 can be controlled through /sys/devices/system/cpu.
395 Say N if you want to disable CPU hotplug.
406 # Common NUMA Features
408 bool "NUMA Memory Allocation and Scheduler Support"
409 depends on SMP && MMU
410 select ARCH_SUPPORTS_NUMA_BALANCING
411 select GENERIC_ARCH_NUMA
412 select NEED_PER_CPU_EMBED_FIRST_CHUNK
414 select USE_PERCPU_NUMA_NODE_ID
416 Enable NUMA (Non-Uniform Memory Access) support.
418 The kernel will try to allocate memory used by a CPU on the
419 local memory of the CPU and add some more NUMA awareness to the kernel.
422 int "Maximum NUMA Nodes (as a power of 2)"
427 Specify the maximum number of NUMA Nodes available on the target
428 system. Increases memory reserved to accommodate various tables.
430 config RISCV_ALTERNATIVE
432 depends on !XIP_KERNEL
434 This Kconfig allows the kernel to automatically patch the
435 erratum or cpufeature required by the execution platform at run
436 time. The code patching overhead is minimal, as it's only done
437 once at boot and once on each module load.
439 config RISCV_ALTERNATIVE_EARLY
441 depends on RISCV_ALTERNATIVE
443 Allows early patching of the kernel for special errata
446 bool "Emit compressed instructions when building Linux"
449 Adds "C" to the ISA subsets that the toolchain is allowed to emit
450 when building Linux, which results in compressed instructions in the
453 If you don't know what to do here, say Y.
455 config RISCV_ISA_SVNAPOT
456 bool "Svnapot extension support for supervisor mode NAPOT pages"
457 depends on 64BIT && MMU
458 depends on RISCV_ALTERNATIVE
461 Allow kernel to detect the Svnapot ISA-extension dynamically at boot
462 time and enable its usage.
464 The Svnapot extension is used to mark contiguous PTEs as a range
465 of contiguous virtual-to-physical translations for a naturally
466 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
467 size. When HUGETLBFS is also selected this option unconditionally
468 allocates some memory for each NAPOT page size supported by the kernel.
469 When optimizing for low memory consumption and for platforms without
470 the Svnapot extension, it may be better to say N here.
472 If you don't know what to do here, say Y.
474 config RISCV_ISA_SVPBMT
475 bool "Svpbmt extension support for supervisor mode page-based memory types"
476 depends on 64BIT && MMU
477 depends on RISCV_ALTERNATIVE
480 Adds support to dynamically detect the presence of the Svpbmt
481 ISA-extension (Supervisor-mode: page-based memory types) and
484 The memory type for a page contains a combination of attributes
485 that indicate the cacheability, idempotency, and ordering
486 properties for access to that page.
488 The Svpbmt extension is only available on 64-bit cpus.
490 If you don't know what to do here, say Y.
492 config TOOLCHAIN_HAS_V
495 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
496 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
497 depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
498 depends on AS_HAS_OPTION_ARCH
501 bool "VECTOR extension support"
502 depends on TOOLCHAIN_HAS_V
504 select DYNAMIC_SIGFRAME
507 Say N here if you want to disable all vector related procedure
510 If you don't know what to do here, say Y.
512 config RISCV_ISA_V_DEFAULT_ENABLE
513 bool "Enable userspace Vector by default"
514 depends on RISCV_ISA_V
517 Say Y here if you want to enable Vector in userspace by default.
518 Otherwise, userspace has to make explicit prctl() call to enable
519 Vector, or enable it via the sysctl interface.
521 If you don't know what to do here, say Y.
523 config TOOLCHAIN_HAS_ZBB
526 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
527 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
528 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
529 depends on AS_HAS_OPTION_ARCH
532 bool "Zbb extension support for bit manipulation instructions"
533 depends on TOOLCHAIN_HAS_ZBB
535 depends on RISCV_ALTERNATIVE
538 Adds support to dynamically detect the presence of the ZBB
539 extension (basic bit manipulation) and enable its usage.
541 The Zbb extension provides instructions to accelerate a number
542 of bit-specific operations (count bit population, sign extending,
545 If you don't know what to do here, say Y.
547 config RISCV_ISA_ZICBOM
548 bool "Zicbom extension support for non-coherent DMA operation"
550 depends on RISCV_ALTERNATIVE
552 select RISCV_DMA_NONCOHERENT
554 Adds support to dynamically detect the presence of the ZICBOM
555 extension (Cache Block Management Operations) and enable its
558 The Zicbom extension can be used to handle for example
559 non-coherent DMA support on devices that need it.
561 If you don't know what to do here, say Y.
563 config RISCV_ISA_ZICBOZ
564 bool "Zicboz extension support for faster zeroing of memory"
566 depends on RISCV_ALTERNATIVE
569 Enable the use of the Zicboz extension (cbo.zero instruction)
572 The Zicboz extension is used for faster zeroing of memory.
574 If you don't know what to do here, say Y.
576 config TOOLCHAIN_HAS_ZIHINTPAUSE
579 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
580 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
581 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
583 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
585 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
586 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd
587 depends on AS_IS_GNU && AS_VERSION >= 23600
589 Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer
590 20191213 version, which moves some instructions from the I extension to
591 the Zicsr and Zifencei extensions. This requires explicitly specifying
592 Zicsr and Zifencei when binutils >= 2.38 or GCC >= 12.1.0. Zicsr
593 and Zifencei are supported in binutils from version 2.36 onwards.
594 To make life easier, and avoid forcing toolchains that default to a
595 newer ISA spec to version 2.2, relax the check to binutils >= 2.36.
596 For clang < 17 or GCC < 11.3.0, for which this is not possible or need
597 special treatment, this is dealt with in TOOLCHAIN_NEEDS_OLD_ISA_SPEC.
599 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
601 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
602 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
603 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d29f5d6ab513c52fd872f532c492e35ae9fd6671
604 depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC && GCC_VERSION < 110300)
606 Certain versions of clang and GCC do not support zicsr and zifencei via
607 -march. This option causes an older ISA spec compatible with these older
608 versions of clang and GCC to be passed to GAS, which has the same result
609 as passing zicsr and zifencei to -march.
615 Say N here if you want to disable all floating-point related procedure
618 If you don't know what to do here, say Y.
621 bool "Independent irq & softirq stacks" if EXPERT
623 select HAVE_IRQ_EXIT_ON_IRQ_STACK
624 select HAVE_SOFTIRQ_ON_OWN_STACK
626 Add independent irq & softirq stacks for percpu to prevent kernel stack
627 overflows. We may save some memory footprint by disabling IRQ_STACKS.
629 config THREAD_SIZE_ORDER
630 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
632 default 1 if 32BIT && !KASAN
633 default 3 if 64BIT && KASAN
636 Specify the Pages of thread stack size (from 4KB to 64KB), which also
637 affects irq stack size, which is equal to thread stack size.
639 endmenu # "Platform type"
641 menu "Kernel features"
643 source "kernel/Kconfig.hz"
646 bool "SBI v0.1 support"
649 This config allows kernel to use SBI v0.1 APIs. This will be
650 deprecated in future once legacy M-mode software are no longer in use.
652 config RISCV_BOOT_SPINWAIT
653 bool "Spinwait booting method"
655 default y if RISCV_SBI_V01 || RISCV_M_MODE
657 This enables support for booting Linux via spinwait method. In the
658 spinwait method, all cores randomly jump to Linux. One of the cores
659 gets chosen via lottery and all other keep spinning on a percpu
660 variable. This method cannot support CPU hotplug and sparse hartid
661 scheme. It should be only enabled for M-mode Linux or platforms relying
662 on older firmware without SBI HSM extension. All other platforms should
663 rely on ordered booting via SBI HSM extension which gets chosen
664 dynamically at runtime if the firmware supports it.
666 Since spinwait is incompatible with sparse hart IDs, it requires
667 NR_CPUS be large enough to contain the physical hart ID of the first
670 If unsure what to do here, say N.
672 config ARCH_SUPPORTS_KEXEC
675 config ARCH_SELECTS_KEXEC
678 select HOTPLUG_CPU if SMP
680 config ARCH_SUPPORTS_KEXEC_FILE
681 def_bool 64BIT && MMU
683 config ARCH_SELECTS_KEXEC_FILE
685 depends on KEXEC_FILE
686 select HAVE_IMA_KEXEC if IMA
689 config ARCH_SUPPORTS_KEXEC_PURGATORY
692 depends on CRYPTO_SHA256=y
694 config ARCH_SUPPORTS_CRASH_DUMP
698 bool "Kernel support for 32-bit U-mode"
700 depends on 64BIT && MMU
702 This option enables support for a 32-bit U-mode running under a 64-bit
703 kernel at S-mode. riscv32-specific components such as system calls,
704 the user helper functions (vdso), signal rt_frame functions and the
705 ptrace interface are handled appropriately by the kernel.
707 If you want to execute 32-bit userspace applications, say Y.
710 bool "Build a relocatable kernel"
711 depends on MMU && 64BIT && !XIP_KERNEL
713 This builds a kernel as a Position Independent Executable (PIE),
714 which retains all relocation metadata required to relocate the
715 kernel binary at runtime to a different virtual address than the
716 address it was linked at.
717 Since RISCV uses the RELA relocation format, this requires a
718 relocation pass at runtime even if the kernel is loaded at the
719 same address it was linked at.
723 config RANDOMIZE_BASE
724 bool "Randomize the address of the kernel image"
726 depends on MMU && 64BIT && !XIP_KERNEL
728 Randomizes the virtual address at which the kernel image is
729 loaded, as a security feature that deters exploit attempts
730 relying on knowledge of the location of kernel internals.
732 It is the bootloader's job to provide entropy, by passing a
733 random u64 value in /chosen/kaslr-seed at kernel entry.
735 When booting via the UEFI stub, it will invoke the firmware's
736 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
737 to the kernel proper. In addition, it will randomise the physical
738 location of the kernel Image as well.
742 endmenu # "Kernel features"
747 string "Built-in kernel command line"
749 For most platforms, the arguments for the kernel's command line
750 are provided at run-time, during boot. However, there are cases
751 where either no arguments are being provided or the provided
752 arguments are insufficient or even invalid.
754 When that occurs, it is possible to define a built-in command
755 line here and choose how the kernel should use it later on.
758 prompt "Built-in command line usage" if CMDLINE != ""
759 default CMDLINE_FALLBACK
761 Choose how the kernel will handle the provided built-in command
764 config CMDLINE_FALLBACK
765 bool "Use bootloader kernel arguments if available"
767 Use the built-in command line as fallback in case we get nothing
768 during boot. This is the default behaviour.
770 config CMDLINE_EXTEND
771 bool "Extend bootloader kernel arguments"
773 The command-line arguments provided during boot will be
774 appended to the built-in command line. This is useful in
775 cases where the provided arguments are insufficient and
776 you don't want to or cannot modify them.
779 bool "Always use the default kernel command string"
781 Always use the built-in command line, even if we get one during
782 boot. This is useful in case you need to override the provided
783 command line on systems where you don't have or want control
792 bool "UEFI runtime support"
793 depends on OF && !XIP_KERNEL
796 select ARCH_SUPPORTS_ACPI if 64BIT
797 select EFI_GENERIC_STUB
798 select EFI_PARAMS_FROM_FDT
799 select EFI_RUNTIME_WRAPPERS
805 This option provides support for runtime services provided
806 by UEFI firmware (such as non-volatile variables, realtime
807 clock, and platform reset). A UEFI stub is also provided to
808 allow the kernel to be booted as an EFI application. This
809 is only useful on systems that have UEFI firmware.
811 config CC_HAVE_STACKPROTECTOR_TLS
812 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
814 config STACKPROTECTOR_PER_TASK
816 depends on !RANDSTRUCT
817 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
819 config PHYS_RAM_BASE_FIXED
820 bool "Explicitly specified physical RAM address"
821 depends on NONPORTABLE
825 hex "Platform Physical RAM address"
826 depends on PHYS_RAM_BASE_FIXED
829 This is the physical address of RAM in the system. It has to be
830 explicitly specified to run early relocations of read-write data
834 bool "Kernel Execute-In-Place from ROM"
835 depends on MMU && SPARSEMEM && NONPORTABLE
836 # This prevents XIP from being enabled by all{yes,mod}config, which
837 # fail to build since XIP doesn't support large kernels.
838 depends on !COMPILE_TEST
839 select PHYS_RAM_BASE_FIXED
841 Execute-In-Place allows the kernel to run from non-volatile storage
842 directly addressable by the CPU, such as NOR flash. This saves RAM
843 space since the text section of the kernel is not loaded from flash
844 to RAM. Read-write sections, such as the data section and stack,
845 are still copied to RAM. The XIP kernel is not compressed since
846 it has to run directly from flash, so it will take more space to
847 store it. The flash address used to link the kernel object files,
848 and for storing it, is configuration dependent. Therefore, if you
849 say Y here, you must know the proper physical address where to
850 store the kernel image depending on your own flash memory usage.
852 Also note that the make target becomes "make xipImage" rather than
853 "make zImage" or "make Image". The final kernel binary to put in
854 ROM memory will be arch/riscv/boot/xipImage.
856 SPARSEMEM is required because the kernel text and rodata that are
857 flash resident are not backed by memmap, then any attempt to get
858 a struct page on those regions will trigger a fault.
863 hex "XIP Kernel Physical Location"
864 depends on XIP_KERNEL
867 This is the physical address in your flash memory the kernel will
868 be linked for and stored to. This address is dependent on your
871 config RISCV_ISA_FALLBACK
872 bool "Permit falling back to parsing riscv,isa for extension support by default"
875 Parsing the "riscv,isa" devicetree property has been deprecated and
876 replaced by a list of explicitly defined strings. For compatibility
877 with existing platforms, the kernel will fall back to parsing the
878 "riscv,isa" property if the replacements are not found.
880 Selecting N here will result in a kernel that does not use the
881 fallback, unless the commandline "riscv_isa_fallback" parameter is
884 Please see the dt-binding, located at
885 Documentation/devicetree/bindings/riscv/extensions.yaml for details
886 on the replacement properties, "riscv,isa-base" and
887 "riscv,isa-extensions".
889 endmenu # "Boot options"
893 depends on OF && NONPORTABLE
894 default y if XIP_KERNEL
903 menu "Power management options"
905 source "kernel/power/Kconfig"
907 # Hibernation is only possible on systems where the SBI implementation has
908 # marked its reserved memory as not accessible from, or does not run
909 # from the same memory as, Linux
910 config ARCH_HIBERNATION_POSSIBLE
913 config ARCH_HIBERNATION_HEADER
916 config ARCH_SUSPEND_POSSIBLE
919 endmenu # "Power management options"
921 menu "CPU Power Management"
923 source "drivers/cpuidle/Kconfig"
925 source "drivers/cpufreq/Kconfig"
927 endmenu # "CPU Power Management"
929 source "arch/riscv/kvm/Kconfig"
931 source "drivers/acpi/Kconfig"