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_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
39 select ARCH_HAS_UBSAN_SANITIZE_ALL
40 select ARCH_HAS_VDSO_DATA
41 select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
42 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
44 select ARCH_SUPPORTS_ATOMIC_RMW
45 select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
46 select ARCH_SUPPORTS_HUGETLBFS if MMU
47 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
48 select ARCH_SUPPORTS_PER_VMA_LOCK if MMU
49 select ARCH_USE_MEMTEST
50 select ARCH_USE_QUEUED_RWLOCKS
51 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
52 select ARCH_WANT_FRAME_POINTERS
53 select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
54 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
55 select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
56 select ARCH_WANT_OPTIMIZE_VMEMMAP
57 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
58 select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
59 select BUILDTIME_TABLE_SORT if MMU
60 select CLINT_TIMER if !MMU
61 select CLONE_BACKWARDS
63 select CPU_PM if CPU_IDLE || HIBERNATION
65 select GENERIC_ARCH_TOPOLOGY
66 select GENERIC_ATOMIC64 if !64BIT
67 select GENERIC_CLOCKEVENTS_BROADCAST if SMP
68 select GENERIC_EARLY_IOREMAP
70 select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
71 select GENERIC_IDLE_POLL_SETUP
72 select GENERIC_IOREMAP if MMU
73 select GENERIC_IRQ_IPI if SMP
74 select GENERIC_IRQ_IPI_MUX if SMP
75 select GENERIC_IRQ_MULTI_HANDLER
76 select GENERIC_IRQ_SHOW
77 select GENERIC_IRQ_SHOW_LEVEL
78 select GENERIC_LIB_DEVMEM_IS_ALLOWED
79 select GENERIC_PCI_IOMAP
80 select GENERIC_PTDUMP if MMU
81 select GENERIC_SCHED_CLOCK
82 select GENERIC_SMP_IDLE_THREAD
83 select GENERIC_TIME_VSYSCALL if MMU && 64BIT
84 select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
85 select HARDIRQS_SW_RESEND
86 select HAS_IOPORT if MMU
87 select HAVE_ARCH_AUDITSYSCALL
88 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
89 select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT && !XIP_KERNEL
90 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
91 select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
92 select HAVE_ARCH_KASAN if MMU && 64BIT
93 select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
94 select HAVE_ARCH_KFENCE if MMU && 64BIT
95 select HAVE_ARCH_KGDB if !XIP_KERNEL
96 select HAVE_ARCH_KGDB_QXFER_PKT
97 select HAVE_ARCH_MMAP_RND_BITS if MMU
98 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
99 select HAVE_ARCH_SECCOMP_FILTER
100 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
101 select HAVE_ARCH_TRACEHOOK
102 select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
103 select HAVE_ARCH_USERFAULTFD_MINOR if 64BIT && USERFAULTFD
104 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT
105 select HAVE_ASM_MODVERSIONS
106 select HAVE_CONTEXT_TRACKING_USER
107 select HAVE_DEBUG_KMEMLEAK
108 select HAVE_DMA_CONTIGUOUS if MMU
109 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
110 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
111 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
112 select HAVE_FUNCTION_GRAPH_TRACER
113 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
114 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
115 select HAVE_EBPF_JIT if MMU
116 select HAVE_FUNCTION_ARG_ACCESS_API
117 select HAVE_FUNCTION_ERROR_INJECTION
118 select HAVE_GCC_PLUGINS
119 select HAVE_GENERIC_VDSO if MMU && 64BIT
120 select HAVE_IRQ_TIME_ACCOUNTING
121 select HAVE_KPROBES if !XIP_KERNEL
122 select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
123 select HAVE_KRETPROBES if !XIP_KERNEL
124 # https://github.com/ClangBuiltLinux/linux/issues/1881
125 select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD
129 select HAVE_PERF_EVENTS
130 select HAVE_PERF_REGS
131 select HAVE_PERF_USER_STACK_DUMP
132 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
133 select HAVE_REGS_AND_STACK_ACCESS_API
134 select HAVE_RETHOOK if !XIP_KERNEL
136 select HAVE_STACKPROTECTOR
137 select HAVE_SYSCALL_TRACEPOINTS
138 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
140 select IRQ_FORCED_THREADING
141 select KASAN_VMALLOC if KASAN
142 select LOCK_MM_AND_FIND_VMA
143 select MODULES_USE_ELF_RELA if MODULES
144 select MODULE_SECTIONS if MODULES
146 select OF_EARLY_FLATTREE
148 select PCI_DOMAINS_GENERIC if PCI
149 select PCI_MSI if PCI
150 select RISCV_ALTERNATIVE if !XIP_KERNEL
152 select RISCV_TIMER if RISCV_SBI
155 select SYSCTL_EXCEPTION_TRACE
156 select THREAD_INFO_IN_TASK
157 select TRACE_IRQFLAGS_SUPPORT
158 select UACCESS_MEMCPY if !MMU
159 select ZONE_DMA32 if 64BIT
161 config CLANG_SUPPORTS_DYNAMIC_FTRACE
163 # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e
164 depends on CLANG_VERSION >= 130000
165 # https://github.com/ClangBuiltLinux/linux/issues/1817
166 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
168 config GCC_SUPPORTS_DYNAMIC_FTRACE
170 depends on $(cc-option,-fpatchable-function-entry=8)
172 config ARCH_MMAP_RND_BITS_MIN
176 config ARCH_MMAP_RND_COMPAT_BITS_MIN
179 # max bits determined by the following formula:
180 # VA_BITS - PAGE_SHIFT - 3
181 config ARCH_MMAP_RND_BITS_MAX
182 default 24 if 64BIT # SV39 based
185 config ARCH_MMAP_RND_COMPAT_BITS_MAX
188 # set if we run in machine mode, cleared if we run in supervisor mode
193 # set if we are running in S-mode and can use SBI calls
196 depends on !RISCV_M_MODE
200 bool "MMU-based Paged Memory Management Support"
203 Select if you want MMU-based virtualised addressing space
204 support by paged memory management. If unsure, say 'Y'.
208 default 0xC0000000 if 32BIT && MMU
209 default 0x80000000 if !MMU
210 default 0xff60000000000000 if 64BIT
212 config KASAN_SHADOW_OFFSET
214 depends on KASAN_GENERIC
215 default 0xdfffffff00000000 if 64BIT
216 default 0xffffffff if 32BIT
218 config ARCH_FLATMEM_ENABLE
221 config ARCH_SPARSEMEM_ENABLE
224 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
225 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
227 config ARCH_SELECT_MEMORY_MODEL
228 def_bool ARCH_SPARSEMEM_ENABLE
230 config ARCH_SUPPORTS_UPROBES
233 config STACKTRACE_SUPPORT
239 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
241 config GENERIC_BUG_RELATIVE_POINTERS
244 config GENERIC_CALIBRATE_DELAY
250 config GENERIC_HWEIGHT
253 config FIX_EARLYCON_MEM
256 config PGTABLE_LEVELS
261 config LOCKDEP_SUPPORT
264 config RISCV_DMA_NONCOHERENT
266 select ARCH_HAS_DMA_PREP_COHERENT
267 select ARCH_HAS_SETUP_DMA_OPS
268 select ARCH_HAS_SYNC_DMA_FOR_CPU
269 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
270 select DMA_DIRECT_REMAP
273 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
275 config AS_HAS_OPTION_ARCH
276 # https://reviews.llvm.org/D123515
278 depends on $(as-instr, .option arch$(comma) +m)
279 depends on !$(as-instr, .option arch$(comma) -i)
281 source "arch/riscv/Kconfig.socs"
282 source "arch/riscv/Kconfig.errata"
287 bool "Allow configurations that result in non-portable kernels"
289 RISC-V kernel binaries are compatible between all known systems
290 whenever possible, but there are some use cases that can only be
291 satisfied by configurations that result in kernel binaries that are
292 not portable between systems.
294 Selecting N does not guarantee kernels will be portable to all known
295 systems. Selecting any of the options guarded by NONPORTABLE will
296 result in kernel binaries that are unlikely to be portable between
305 This selects the base ISA that this kernel will target and must match
310 depends on NONPORTABLE
312 select GENERIC_LIB_ASHLDI3
313 select GENERIC_LIB_ASHRDI3
314 select GENERIC_LIB_LSHRDI3
315 select GENERIC_LIB_UCMPDI2
320 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
321 select SWIOTLB if MMU
325 # We must be able to map all physical memory into the kernel, but the compiler
326 # is still a bit more efficient when generating code if it's setup in a manner
327 # such that it can only map 2GiB of memory.
329 prompt "Kernel Code Model"
330 default CMODEL_MEDLOW if 32BIT
331 default CMODEL_MEDANY if 64BIT
334 bool "medium low code model"
336 bool "medium any code model"
339 config MODULE_SECTIONS
341 select HAVE_MOD_ARCH_SPECIFIC
344 bool "Symmetric Multi-Processing"
346 This enables support for systems with more than one CPU. If
347 you say N here, the kernel will run on single and
348 multiprocessor machines, but will use only one CPU of a
349 multiprocessor machine. If you say Y here, the kernel will run
350 on many, but not all, single processor machines. On a single
351 processor machine, the kernel will run faster if you say N
354 If you don't know what to do here, say N.
357 bool "Multi-core scheduler support"
360 Multi-core scheduler support improves the CPU scheduler's decision
361 making when dealing with multi-core CPU chips at a cost of slightly
362 increased overhead in some places. If unsure say N here.
365 int "Maximum number of CPUs (2-512)"
367 range 2 512 if !RISCV_SBI_V01
368 range 2 32 if RISCV_SBI_V01 && 32BIT
369 range 2 64 if RISCV_SBI_V01 && 64BIT
370 default "32" if 32BIT
371 default "64" if 64BIT
374 bool "Support for hot-pluggable CPUs"
376 select GENERIC_IRQ_MIGRATION
379 Say Y here to experiment with turning CPUs off and on. CPUs
380 can be controlled through /sys/devices/system/cpu.
382 Say N if you want to disable CPU hotplug.
393 # Common NUMA Features
395 bool "NUMA Memory Allocation and Scheduler Support"
396 depends on SMP && MMU
397 select ARCH_SUPPORTS_NUMA_BALANCING
398 select GENERIC_ARCH_NUMA
399 select NEED_PER_CPU_EMBED_FIRST_CHUNK
401 select USE_PERCPU_NUMA_NODE_ID
403 Enable NUMA (Non-Uniform Memory Access) support.
405 The kernel will try to allocate memory used by a CPU on the
406 local memory of the CPU and add some more NUMA awareness to the kernel.
409 int "Maximum NUMA Nodes (as a power of 2)"
414 Specify the maximum number of NUMA Nodes available on the target
415 system. Increases memory reserved to accommodate various tables.
417 config RISCV_ALTERNATIVE
419 depends on !XIP_KERNEL
421 This Kconfig allows the kernel to automatically patch the
422 erratum or cpufeature required by the execution platform at run
423 time. The code patching overhead is minimal, as it's only done
424 once at boot and once on each module load.
426 config RISCV_ALTERNATIVE_EARLY
428 depends on RISCV_ALTERNATIVE
430 Allows early patching of the kernel for special errata
433 bool "Emit compressed instructions when building Linux"
436 Adds "C" to the ISA subsets that the toolchain is allowed to emit
437 when building Linux, which results in compressed instructions in the
440 If you don't know what to do here, say Y.
442 config RISCV_ISA_SVNAPOT
443 bool "Svnapot extension support for supervisor mode NAPOT pages"
444 depends on 64BIT && MMU
445 depends on RISCV_ALTERNATIVE
448 Allow kernel to detect the Svnapot ISA-extension dynamically at boot
449 time and enable its usage.
451 The Svnapot extension is used to mark contiguous PTEs as a range
452 of contiguous virtual-to-physical translations for a naturally
453 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
454 size. When HUGETLBFS is also selected this option unconditionally
455 allocates some memory for each NAPOT page size supported by the kernel.
456 When optimizing for low memory consumption and for platforms without
457 the Svnapot extension, it may be better to say N here.
459 If you don't know what to do here, say Y.
461 config RISCV_ISA_SVPBMT
462 bool "Svpbmt extension support for supervisor mode page-based memory types"
463 depends on 64BIT && MMU
464 depends on RISCV_ALTERNATIVE
467 Adds support to dynamically detect the presence of the Svpbmt
468 ISA-extension (Supervisor-mode: page-based memory types) and
471 The memory type for a page contains a combination of attributes
472 that indicate the cacheability, idempotency, and ordering
473 properties for access to that page.
475 The Svpbmt extension is only available on 64-bit cpus.
477 If you don't know what to do here, say Y.
479 config TOOLCHAIN_HAS_V
482 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
483 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
484 depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
485 depends on AS_HAS_OPTION_ARCH
488 bool "VECTOR extension support"
489 depends on TOOLCHAIN_HAS_V
491 select DYNAMIC_SIGFRAME
494 Say N here if you want to disable all vector related procedure
497 If you don't know what to do here, say Y.
499 config RISCV_ISA_V_DEFAULT_ENABLE
500 bool "Enable userspace Vector by default"
501 depends on RISCV_ISA_V
504 Say Y here if you want to enable Vector in userspace by default.
505 Otherwise, userspace has to make explicit prctl() call to enable
506 Vector, or enable it via the sysctl interface.
508 If you don't know what to do here, say Y.
510 config TOOLCHAIN_HAS_ZBB
513 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
514 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
515 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
516 depends on AS_HAS_OPTION_ARCH
519 bool "Zbb extension support for bit manipulation instructions"
520 depends on TOOLCHAIN_HAS_ZBB
522 depends on RISCV_ALTERNATIVE
525 Adds support to dynamically detect the presence of the ZBB
526 extension (basic bit manipulation) and enable its usage.
528 The Zbb extension provides instructions to accelerate a number
529 of bit-specific operations (count bit population, sign extending,
532 If you don't know what to do here, say Y.
534 config RISCV_ISA_ZICBOM
535 bool "Zicbom extension support for non-coherent DMA operation"
537 depends on RISCV_ALTERNATIVE
539 select RISCV_DMA_NONCOHERENT
541 Adds support to dynamically detect the presence of the ZICBOM
542 extension (Cache Block Management Operations) and enable its
545 The Zicbom extension can be used to handle for example
546 non-coherent DMA support on devices that need it.
548 If you don't know what to do here, say Y.
550 config RISCV_ISA_ZICBOZ
551 bool "Zicboz extension support for faster zeroing of memory"
553 depends on RISCV_ALTERNATIVE
556 Enable the use of the Zicboz extension (cbo.zero instruction)
559 The Zicboz extension is used for faster zeroing of memory.
561 If you don't know what to do here, say Y.
563 config TOOLCHAIN_HAS_ZIHINTPAUSE
566 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
567 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
568 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
570 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
572 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
573 depends on AS_IS_GNU && AS_VERSION >= 23800
575 Newer binutils versions default to ISA spec version 20191213 which
576 moves some instructions from the I extension to the Zicsr and Zifencei
579 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
581 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
582 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
583 depends on CC_IS_CLANG && CLANG_VERSION < 170000
585 Certain versions of clang do not support zicsr and zifencei via -march
586 but newer versions of binutils require it for the reasons noted in the
587 help text of CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. This
588 option causes an older ISA spec compatible with these older versions
589 of clang to be passed to GAS, which has the same result as passing zicsr
590 and zifencei to -march.
596 Say N here if you want to disable all floating-point related procedure
599 If you don't know what to do here, say Y.
602 bool "Independent irq & softirq stacks" if EXPERT
604 select HAVE_IRQ_EXIT_ON_IRQ_STACK
605 select HAVE_SOFTIRQ_ON_OWN_STACK
607 Add independent irq & softirq stacks for percpu to prevent kernel stack
608 overflows. We may save some memory footprint by disabling IRQ_STACKS.
610 config THREAD_SIZE_ORDER
611 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
613 default 1 if 32BIT && !KASAN
614 default 3 if 64BIT && KASAN
617 Specify the Pages of thread stack size (from 4KB to 64KB), which also
618 affects irq stack size, which is equal to thread stack size.
620 endmenu # "Platform type"
622 menu "Kernel features"
624 source "kernel/Kconfig.hz"
627 bool "SBI v0.1 support"
630 This config allows kernel to use SBI v0.1 APIs. This will be
631 deprecated in future once legacy M-mode software are no longer in use.
633 config RISCV_BOOT_SPINWAIT
634 bool "Spinwait booting method"
636 default y if RISCV_SBI_V01 || RISCV_M_MODE
638 This enables support for booting Linux via spinwait method. In the
639 spinwait method, all cores randomly jump to Linux. One of the cores
640 gets chosen via lottery and all other keep spinning on a percpu
641 variable. This method cannot support CPU hotplug and sparse hartid
642 scheme. It should be only enabled for M-mode Linux or platforms relying
643 on older firmware without SBI HSM extension. All other platforms should
644 rely on ordered booting via SBI HSM extension which gets chosen
645 dynamically at runtime if the firmware supports it.
647 Since spinwait is incompatible with sparse hart IDs, it requires
648 NR_CPUS be large enough to contain the physical hart ID of the first
651 If unsure what to do here, say N.
654 bool "Kexec system call"
656 select HOTPLUG_CPU if SMP
659 kexec is a system call that implements the ability to shutdown your
660 current kernel, and to start another kernel. It is like a reboot
661 but it is independent of the system firmware. And like a reboot
662 you can start any kernel with it, not just Linux.
664 The name comes from the similarity to the exec system call.
667 bool "kexec file based systmem call"
668 depends on 64BIT && MMU
669 select HAVE_IMA_KEXEC if IMA
673 This is new version of kexec system call. This system call is
674 file based and takes file descriptors as system call argument
675 for kernel and initramfs as opposed to list of segments as
676 accepted by previous system call.
678 If you don't know what to do here, say Y.
680 config ARCH_HAS_KEXEC_PURGATORY
683 depends on CRYPTO_SHA256=y
686 bool "Build kdump crash kernel"
688 Generate crash dump after being started by kexec. This should
689 be normally only set in special crash dump kernels which are
690 loaded in the main kernel with kexec-tools into a specially
691 reserved region and then later executed after a crash by
694 For more details see Documentation/admin-guide/kdump/kdump.rst
697 bool "Kernel support for 32-bit U-mode"
699 depends on 64BIT && MMU
701 This option enables support for a 32-bit U-mode running under a 64-bit
702 kernel at S-mode. riscv32-specific components such as system calls,
703 the user helper functions (vdso), signal rt_frame functions and the
704 ptrace interface are handled appropriately by the kernel.
706 If you want to execute 32-bit userspace applications, say Y.
709 bool "Build a relocatable kernel"
710 depends on MMU && 64BIT && !XIP_KERNEL
712 This builds a kernel as a Position Independent Executable (PIE),
713 which retains all relocation metadata required to relocate the
714 kernel binary at runtime to a different virtual address than the
715 address it was linked at.
716 Since RISCV uses the RELA relocation format, this requires a
717 relocation pass at runtime even if the kernel is loaded at the
718 same address it was linked at.
722 config RANDOMIZE_BASE
723 bool "Randomize the address of the kernel image"
725 depends on MMU && 64BIT && !XIP_KERNEL
727 Randomizes the virtual address at which the kernel image is
728 loaded, as a security feature that deters exploit attempts
729 relying on knowledge of the location of kernel internals.
731 It is the bootloader's job to provide entropy, by passing a
732 random u64 value in /chosen/kaslr-seed at kernel entry.
734 When booting via the UEFI stub, it will invoke the firmware's
735 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
736 to the kernel proper. In addition, it will randomise the physical
737 location of the kernel Image as well.
741 endmenu # "Kernel features"
746 string "Built-in kernel command line"
748 For most platforms, the arguments for the kernel's command line
749 are provided at run-time, during boot. However, there are cases
750 where either no arguments are being provided or the provided
751 arguments are insufficient or even invalid.
753 When that occurs, it is possible to define a built-in command
754 line here and choose how the kernel should use it later on.
757 prompt "Built-in command line usage" if CMDLINE != ""
758 default CMDLINE_FALLBACK
760 Choose how the kernel will handle the provided built-in command
763 config CMDLINE_FALLBACK
764 bool "Use bootloader kernel arguments if available"
766 Use the built-in command line as fallback in case we get nothing
767 during boot. This is the default behaviour.
769 config CMDLINE_EXTEND
770 bool "Extend bootloader kernel arguments"
772 The command-line arguments provided during boot will be
773 appended to the built-in command line. This is useful in
774 cases where the provided arguments are insufficient and
775 you don't want to or cannot modify them.
778 bool "Always use the default kernel command string"
780 Always use the built-in command line, even if we get one during
781 boot. This is useful in case you need to override the provided
782 command line on systems where you don't have or want control
791 bool "UEFI runtime support"
792 depends on OF && !XIP_KERNEL
795 select ARCH_SUPPORTS_ACPI if 64BIT
796 select EFI_GENERIC_STUB
797 select EFI_PARAMS_FROM_FDT
798 select EFI_RUNTIME_WRAPPERS
804 This option provides support for runtime services provided
805 by UEFI firmware (such as non-volatile variables, realtime
806 clock, and platform reset). A UEFI stub is also provided to
807 allow the kernel to be booted as an EFI application. This
808 is only useful on systems that have UEFI firmware.
810 config CC_HAVE_STACKPROTECTOR_TLS
811 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
813 config STACKPROTECTOR_PER_TASK
815 depends on !RANDSTRUCT
816 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
818 config PHYS_RAM_BASE_FIXED
819 bool "Explicitly specified physical RAM address"
820 depends on NONPORTABLE
824 hex "Platform Physical RAM address"
825 depends on PHYS_RAM_BASE_FIXED
828 This is the physical address of RAM in the system. It has to be
829 explicitly specified to run early relocations of read-write data
833 bool "Kernel Execute-In-Place from ROM"
834 depends on MMU && SPARSEMEM && NONPORTABLE
835 # This prevents XIP from being enabled by all{yes,mod}config, which
836 # fail to build since XIP doesn't support large kernels.
837 depends on !COMPILE_TEST
838 select PHYS_RAM_BASE_FIXED
840 Execute-In-Place allows the kernel to run from non-volatile storage
841 directly addressable by the CPU, such as NOR flash. This saves RAM
842 space since the text section of the kernel is not loaded from flash
843 to RAM. Read-write sections, such as the data section and stack,
844 are still copied to RAM. The XIP kernel is not compressed since
845 it has to run directly from flash, so it will take more space to
846 store it. The flash address used to link the kernel object files,
847 and for storing it, is configuration dependent. Therefore, if you
848 say Y here, you must know the proper physical address where to
849 store the kernel image depending on your own flash memory usage.
851 Also note that the make target becomes "make xipImage" rather than
852 "make zImage" or "make Image". The final kernel binary to put in
853 ROM memory will be arch/riscv/boot/xipImage.
855 SPARSEMEM is required because the kernel text and rodata that are
856 flash resident are not backed by memmap, then any attempt to get
857 a struct page on those regions will trigger a fault.
862 hex "XIP Kernel Physical Location"
863 depends on XIP_KERNEL
866 This is the physical address in your flash memory the kernel will
867 be linked for and stored to. This address is dependent on your
870 endmenu # "Boot options"
874 depends on OF && NONPORTABLE
875 default y if XIP_KERNEL
884 menu "Power management options"
886 source "kernel/power/Kconfig"
888 # Hibernation is only possible on systems where the SBI implementation has
889 # marked its reserved memory as not accessible from, or does not run
890 # from the same memory as, Linux
891 config ARCH_HIBERNATION_POSSIBLE
894 config ARCH_HIBERNATION_HEADER
897 config ARCH_SUSPEND_POSSIBLE
900 endmenu # "Power management options"
902 menu "CPU Power Management"
904 source "drivers/cpuidle/Kconfig"
906 source "drivers/cpufreq/Kconfig"
908 endmenu # "CPU Power Management"
910 source "arch/riscv/kvm/Kconfig"
912 source "drivers/acpi/Kconfig"