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 ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
16 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
17 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
18 select ARCH_HAS_BINFMT_FLAT
19 select ARCH_HAS_CURRENT_STACK_POINTER
20 select ARCH_HAS_DEBUG_VIRTUAL if MMU
21 select ARCH_HAS_DEBUG_VM_PGTABLE
22 select ARCH_HAS_DEBUG_WX
23 select ARCH_HAS_FORTIFY_SOURCE
24 select ARCH_HAS_GCOV_PROFILE_ALL
25 select ARCH_HAS_GIGANTIC_PAGE
27 select ARCH_HAS_MMIOWB
28 select ARCH_HAS_PMEM_API
29 select ARCH_HAS_PTE_SPECIAL
30 select ARCH_HAS_SET_DIRECT_MAP if MMU
31 select ARCH_HAS_SET_MEMORY if MMU
32 select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
33 select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
34 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
35 select ARCH_HAS_UBSAN_SANITIZE_ALL
36 select ARCH_HAS_VDSO_DATA
37 select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
38 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
40 select ARCH_SUPPORTS_ATOMIC_RMW
41 select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
42 select ARCH_SUPPORTS_HUGETLBFS if MMU
43 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
44 select ARCH_USE_MEMTEST
45 select ARCH_USE_QUEUED_RWLOCKS
46 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
47 select ARCH_WANT_FRAME_POINTERS
48 select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
49 select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
50 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
51 select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
52 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
53 select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
54 select BUILDTIME_TABLE_SORT if MMU
55 select CLINT_TIMER if !MMU
56 select CLONE_BACKWARDS
58 select CPU_PM if CPU_IDLE
60 select GENERIC_ARCH_TOPOLOGY
61 select GENERIC_ATOMIC64 if !64BIT
62 select GENERIC_CLOCKEVENTS_BROADCAST if SMP
63 select GENERIC_EARLY_IOREMAP
65 select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
66 select GENERIC_IDLE_POLL_SETUP
67 select GENERIC_IOREMAP if MMU
68 select GENERIC_IRQ_IPI if SMP
69 select GENERIC_IRQ_IPI_MUX if SMP
70 select GENERIC_IRQ_MULTI_HANDLER
71 select GENERIC_IRQ_SHOW
72 select GENERIC_IRQ_SHOW_LEVEL
73 select GENERIC_LIB_DEVMEM_IS_ALLOWED
74 select GENERIC_PCI_IOMAP
75 select GENERIC_PTDUMP if MMU
76 select GENERIC_SCHED_CLOCK
77 select GENERIC_SMP_IDLE_THREAD
78 select GENERIC_TIME_VSYSCALL if MMU && 64BIT
79 select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
80 select HARDIRQS_SW_RESEND
81 select HAS_IOPORT if MMU
82 select HAVE_ARCH_AUDITSYSCALL
83 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
84 select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT && !XIP_KERNEL
85 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
86 select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
87 select HAVE_ARCH_KASAN if MMU && 64BIT
88 select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
89 select HAVE_ARCH_KFENCE if MMU && 64BIT
90 select HAVE_ARCH_KGDB if !XIP_KERNEL
91 select HAVE_ARCH_KGDB_QXFER_PKT
92 select HAVE_ARCH_MMAP_RND_BITS if MMU
93 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
94 select HAVE_ARCH_SECCOMP_FILTER
95 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
96 select HAVE_ARCH_TRACEHOOK
97 select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
98 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT
99 select HAVE_ASM_MODVERSIONS
100 select HAVE_CONTEXT_TRACKING_USER
101 select HAVE_DEBUG_KMEMLEAK
102 select HAVE_DMA_CONTIGUOUS if MMU
103 select HAVE_EBPF_JIT if MMU
104 select HAVE_FUNCTION_ARG_ACCESS_API
105 select HAVE_FUNCTION_ERROR_INJECTION
106 select HAVE_GCC_PLUGINS
107 select HAVE_GENERIC_VDSO if MMU && 64BIT
108 select HAVE_IRQ_TIME_ACCOUNTING
109 select HAVE_KPROBES if !XIP_KERNEL
110 select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
111 select HAVE_KRETPROBES if !XIP_KERNEL
112 select HAVE_RETHOOK if !XIP_KERNEL
116 select HAVE_PERF_EVENTS
117 select HAVE_PERF_REGS
118 select HAVE_PERF_USER_STACK_DUMP
119 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
120 select HAVE_REGS_AND_STACK_ACCESS_API
122 select HAVE_STACKPROTECTOR
123 select HAVE_SYSCALL_TRACEPOINTS
125 select IRQ_FORCED_THREADING
126 select KASAN_VMALLOC if KASAN
127 select MODULES_USE_ELF_RELA if MODULES
128 select MODULE_SECTIONS if MODULES
130 select OF_DMA_DEFAULT_COHERENT
131 select OF_EARLY_FLATTREE
133 select PCI_DOMAINS_GENERIC if PCI
134 select PCI_MSI if PCI
135 select RISCV_ALTERNATIVE if !XIP_KERNEL
137 select RISCV_TIMER if RISCV_SBI
140 select SYSCTL_EXCEPTION_TRACE
141 select THREAD_INFO_IN_TASK
142 select TRACE_IRQFLAGS_SUPPORT
143 select UACCESS_MEMCPY if !MMU
144 select ZONE_DMA32 if 64BIT
145 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8)
146 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
147 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
148 select HAVE_FUNCTION_GRAPH_TRACER
149 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
151 config ARCH_MMAP_RND_BITS_MIN
155 config ARCH_MMAP_RND_COMPAT_BITS_MIN
158 # max bits determined by the following formula:
159 # VA_BITS - PAGE_SHIFT - 3
160 config ARCH_MMAP_RND_BITS_MAX
161 default 24 if 64BIT # SV39 based
164 config ARCH_MMAP_RND_COMPAT_BITS_MAX
167 # set if we run in machine mode, cleared if we run in supervisor mode
172 # set if we are running in S-mode and can use SBI calls
175 depends on !RISCV_M_MODE
179 bool "MMU-based Paged Memory Management Support"
182 Select if you want MMU-based virtualised addressing space
183 support by paged memory management. If unsure, say 'Y'.
187 default 0xC0000000 if 32BIT && MMU
188 default 0x80000000 if !MMU
189 default 0xff60000000000000 if 64BIT
191 config KASAN_SHADOW_OFFSET
193 depends on KASAN_GENERIC
194 default 0xdfffffff00000000 if 64BIT
195 default 0xffffffff if 32BIT
197 config ARCH_FLATMEM_ENABLE
200 config ARCH_SPARSEMEM_ENABLE
203 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
204 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
206 config ARCH_SELECT_MEMORY_MODEL
207 def_bool ARCH_SPARSEMEM_ENABLE
209 config ARCH_SUPPORTS_UPROBES
212 config STACKTRACE_SUPPORT
218 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
220 config GENERIC_BUG_RELATIVE_POINTERS
223 config GENERIC_CALIBRATE_DELAY
229 config GENERIC_HWEIGHT
232 config FIX_EARLYCON_MEM
235 config PGTABLE_LEVELS
240 config LOCKDEP_SUPPORT
243 config RISCV_DMA_NONCOHERENT
245 select ARCH_HAS_DMA_PREP_COHERENT
246 select ARCH_HAS_SETUP_DMA_OPS
247 select ARCH_HAS_SYNC_DMA_FOR_CPU
248 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
249 select DMA_DIRECT_REMAP
252 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
254 source "arch/riscv/Kconfig.socs"
255 source "arch/riscv/Kconfig.errata"
260 bool "Allow configurations that result in non-portable kernels"
262 RISC-V kernel binaries are compatible between all known systems
263 whenever possible, but there are some use cases that can only be
264 satisfied by configurations that result in kernel binaries that are
265 not portable between systems.
267 Selecting N does not guarantee kernels will be portable to all known
268 systems. Selecting any of the options guarded by NONPORTABLE will
269 result in kernel binaries that are unlikely to be portable between
278 This selects the base ISA that this kernel will target and must match
283 depends on NONPORTABLE
285 select GENERIC_LIB_ASHLDI3
286 select GENERIC_LIB_ASHRDI3
287 select GENERIC_LIB_LSHRDI3
288 select GENERIC_LIB_UCMPDI2
293 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
294 select SWIOTLB if MMU
298 # We must be able to map all physical memory into the kernel, but the compiler
299 # is still a bit more efficient when generating code if it's setup in a manner
300 # such that it can only map 2GiB of memory.
302 prompt "Kernel Code Model"
303 default CMODEL_MEDLOW if 32BIT
304 default CMODEL_MEDANY if 64BIT
307 bool "medium low code model"
309 bool "medium any code model"
312 config MODULE_SECTIONS
314 select HAVE_MOD_ARCH_SPECIFIC
317 bool "Symmetric Multi-Processing"
319 This enables support for systems with more than one CPU. If
320 you say N here, the kernel will run on single and
321 multiprocessor machines, but will use only one CPU of a
322 multiprocessor machine. If you say Y here, the kernel will run
323 on many, but not all, single processor machines. On a single
324 processor machine, the kernel will run faster if you say N
327 If you don't know what to do here, say N.
330 bool "Multi-core scheduler support"
333 Multi-core scheduler support improves the CPU scheduler's decision
334 making when dealing with multi-core CPU chips at a cost of slightly
335 increased overhead in some places. If unsure say N here.
338 int "Maximum number of CPUs (2-512)"
340 range 2 512 if !RISCV_SBI_V01
341 range 2 32 if RISCV_SBI_V01 && 32BIT
342 range 2 64 if RISCV_SBI_V01 && 64BIT
343 default "32" if 32BIT
344 default "64" if 64BIT
347 bool "Support for hot-pluggable CPUs"
349 select GENERIC_IRQ_MIGRATION
352 Say Y here to experiment with turning CPUs off and on. CPUs
353 can be controlled through /sys/devices/system/cpu.
355 Say N if you want to disable CPU hotplug.
366 # Common NUMA Features
368 bool "NUMA Memory Allocation and Scheduler Support"
369 depends on SMP && MMU
370 select ARCH_SUPPORTS_NUMA_BALANCING
371 select GENERIC_ARCH_NUMA
372 select NEED_PER_CPU_EMBED_FIRST_CHUNK
374 select USE_PERCPU_NUMA_NODE_ID
376 Enable NUMA (Non-Uniform Memory Access) support.
378 The kernel will try to allocate memory used by a CPU on the
379 local memory of the CPU and add some more NUMA awareness to the kernel.
382 int "Maximum NUMA Nodes (as a power of 2)"
387 Specify the maximum number of NUMA Nodes available on the target
388 system. Increases memory reserved to accommodate various tables.
390 config RISCV_ALTERNATIVE
392 depends on !XIP_KERNEL
394 This Kconfig allows the kernel to automatically patch the
395 erratum or cpufeature required by the execution platform at run
396 time. The code patching overhead is minimal, as it's only done
397 once at boot and once on each module load.
399 config RISCV_ALTERNATIVE_EARLY
401 depends on RISCV_ALTERNATIVE
403 Allows early patching of the kernel for special errata
406 bool "Emit compressed instructions when building Linux"
409 Adds "C" to the ISA subsets that the toolchain is allowed to emit
410 when building Linux, which results in compressed instructions in the
413 If you don't know what to do here, say Y.
415 config RISCV_ISA_SVNAPOT
416 bool "Svnapot extension support for supervisor mode NAPOT pages"
417 depends on 64BIT && MMU
418 depends on RISCV_ALTERNATIVE
421 Allow kernel to detect the Svnapot ISA-extension dynamically at boot
422 time and enable its usage.
424 The Svnapot extension is used to mark contiguous PTEs as a range
425 of contiguous virtual-to-physical translations for a naturally
426 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
427 size. When HUGETLBFS is also selected this option unconditionally
428 allocates some memory for each NAPOT page size supported by the kernel.
429 When optimizing for low memory consumption and for platforms without
430 the Svnapot extension, it may be better to say N here.
432 If you don't know what to do here, say Y.
434 config RISCV_ISA_SVPBMT
435 bool "Svpbmt extension support for supervisor mode page-based memory types"
436 depends on 64BIT && MMU
437 depends on RISCV_ALTERNATIVE
440 Adds support to dynamically detect the presence of the Svpbmt
441 ISA-extension (Supervisor-mode: page-based memory types) and
444 The memory type for a page contains a combination of attributes
445 that indicate the cacheability, idempotency, and ordering
446 properties for access to that page.
448 The Svpbmt extension is only available on 64-bit cpus.
450 If you don't know what to do here, say Y.
452 config TOOLCHAIN_HAS_ZBB
455 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
456 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
457 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
461 bool "Zbb extension support for bit manipulation instructions"
462 depends on TOOLCHAIN_HAS_ZBB
464 depends on RISCV_ALTERNATIVE
467 Adds support to dynamically detect the presence of the ZBB
468 extension (basic bit manipulation) and enable its usage.
470 The Zbb extension provides instructions to accelerate a number
471 of bit-specific operations (count bit population, sign extending,
474 If you don't know what to do here, say Y.
476 config RISCV_ISA_ZICBOM
477 bool "Zicbom extension support for non-coherent DMA operation"
479 depends on RISCV_ALTERNATIVE
481 select RISCV_DMA_NONCOHERENT
483 Adds support to dynamically detect the presence of the ZICBOM
484 extension (Cache Block Management Operations) and enable its
487 The Zicbom extension can be used to handle for example
488 non-coherent DMA support on devices that need it.
490 If you don't know what to do here, say Y.
492 config RISCV_ISA_ZICBOZ
493 bool "Zicboz extension support for faster zeroing of memory"
495 depends on RISCV_ALTERNATIVE
498 Enable the use of the Zicboz extension (cbo.zero instruction)
501 The Zicboz extension is used for faster zeroing of memory.
503 If you don't know what to do here, say Y.
505 config TOOLCHAIN_HAS_ZIHINTPAUSE
508 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
509 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
510 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
512 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
514 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
515 depends on AS_IS_GNU && AS_VERSION >= 23800
517 Newer binutils versions default to ISA spec version 20191213 which
518 moves some instructions from the I extension to the Zicsr and Zifencei
521 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
523 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
524 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
525 depends on CC_IS_CLANG && CLANG_VERSION < 170000
527 Certain versions of clang do not support zicsr and zifencei via -march
528 but newer versions of binutils require it for the reasons noted in the
529 help text of CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. This
530 option causes an older ISA spec compatible with these older versions
531 of clang to be passed to GAS, which has the same result as passing zicsr
532 and zifencei to -march.
538 Say N here if you want to disable all floating-point related procedure
541 If you don't know what to do here, say Y.
543 endmenu # "Platform type"
545 menu "Kernel features"
547 source "kernel/Kconfig.hz"
550 bool "SBI v0.1 support"
553 This config allows kernel to use SBI v0.1 APIs. This will be
554 deprecated in future once legacy M-mode software are no longer in use.
556 config RISCV_BOOT_SPINWAIT
557 bool "Spinwait booting method"
559 default y if RISCV_SBI_V01 || RISCV_M_MODE
561 This enables support for booting Linux via spinwait method. In the
562 spinwait method, all cores randomly jump to Linux. One of the cores
563 gets chosen via lottery and all other keep spinning on a percpu
564 variable. This method cannot support CPU hotplug and sparse hartid
565 scheme. It should be only enabled for M-mode Linux or platforms relying
566 on older firmware without SBI HSM extension. All other platforms should
567 rely on ordered booting via SBI HSM extension which gets chosen
568 dynamically at runtime if the firmware supports it.
570 Since spinwait is incompatible with sparse hart IDs, it requires
571 NR_CPUS be large enough to contain the physical hart ID of the first
574 If unsure what to do here, say N.
577 bool "Kexec system call"
579 select HOTPLUG_CPU if SMP
582 kexec is a system call that implements the ability to shutdown your
583 current kernel, and to start another kernel. It is like a reboot
584 but it is independent of the system firmware. And like a reboot
585 you can start any kernel with it, not just Linux.
587 The name comes from the similarity to the exec system call.
590 bool "kexec file based systmem call"
591 depends on 64BIT && MMU
592 select HAVE_IMA_KEXEC if IMA
596 This is new version of kexec system call. This system call is
597 file based and takes file descriptors as system call argument
598 for kernel and initramfs as opposed to list of segments as
599 accepted by previous system call.
601 If you don't know what to do here, say Y.
603 config ARCH_HAS_KEXEC_PURGATORY
606 depends on CRYPTO_SHA256=y
609 bool "Build kdump crash kernel"
611 Generate crash dump after being started by kexec. This should
612 be normally only set in special crash dump kernels which are
613 loaded in the main kernel with kexec-tools into a specially
614 reserved region and then later executed after a crash by
617 For more details see Documentation/admin-guide/kdump/kdump.rst
620 bool "Kernel support for 32-bit U-mode"
622 depends on 64BIT && MMU
624 This option enables support for a 32-bit U-mode running under a 64-bit
625 kernel at S-mode. riscv32-specific components such as system calls,
626 the user helper functions (vdso), signal rt_frame functions and the
627 ptrace interface are handled appropriately by the kernel.
629 If you want to execute 32-bit userspace applications, say Y.
632 bool "Build a relocatable kernel"
633 depends on MMU && 64BIT && !XIP_KERNEL
635 This builds a kernel as a Position Independent Executable (PIE),
636 which retains all relocation metadata required to relocate the
637 kernel binary at runtime to a different virtual address than the
638 address it was linked at.
639 Since RISCV uses the RELA relocation format, this requires a
640 relocation pass at runtime even if the kernel is loaded at the
641 same address it was linked at.
645 endmenu # "Kernel features"
650 string "Built-in kernel command line"
652 For most platforms, the arguments for the kernel's command line
653 are provided at run-time, during boot. However, there are cases
654 where either no arguments are being provided or the provided
655 arguments are insufficient or even invalid.
657 When that occurs, it is possible to define a built-in command
658 line here and choose how the kernel should use it later on.
661 prompt "Built-in command line usage" if CMDLINE != ""
662 default CMDLINE_FALLBACK
664 Choose how the kernel will handle the provided built-in command
667 config CMDLINE_FALLBACK
668 bool "Use bootloader kernel arguments if available"
670 Use the built-in command line as fallback in case we get nothing
671 during boot. This is the default behaviour.
673 config CMDLINE_EXTEND
674 bool "Extend bootloader kernel arguments"
676 The command-line arguments provided during boot will be
677 appended to the built-in command line. This is useful in
678 cases where the provided arguments are insufficient and
679 you don't want to or cannot modify them.
682 bool "Always use the default kernel command string"
684 Always use the built-in command line, even if we get one during
685 boot. This is useful in case you need to override the provided
686 command line on systems where you don't have or want control
695 bool "UEFI runtime support"
696 depends on OF && !XIP_KERNEL
699 select EFI_GENERIC_STUB
700 select EFI_PARAMS_FROM_FDT
701 select EFI_RUNTIME_WRAPPERS
707 This option provides support for runtime services provided
708 by UEFI firmware (such as non-volatile variables, realtime
709 clock, and platform reset). A UEFI stub is also provided to
710 allow the kernel to be booted as an EFI application. This
711 is only useful on systems that have UEFI firmware.
713 config CC_HAVE_STACKPROTECTOR_TLS
714 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
716 config STACKPROTECTOR_PER_TASK
718 depends on !RANDSTRUCT
719 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
721 config PHYS_RAM_BASE_FIXED
722 bool "Explicitly specified physical RAM address"
723 depends on NONPORTABLE
727 hex "Platform Physical RAM address"
728 depends on PHYS_RAM_BASE_FIXED
731 This is the physical address of RAM in the system. It has to be
732 explicitly specified to run early relocations of read-write data
736 bool "Kernel Execute-In-Place from ROM"
737 depends on MMU && SPARSEMEM && NONPORTABLE
738 # This prevents XIP from being enabled by all{yes,mod}config, which
739 # fail to build since XIP doesn't support large kernels.
740 depends on !COMPILE_TEST
741 select PHYS_RAM_BASE_FIXED
743 Execute-In-Place allows the kernel to run from non-volatile storage
744 directly addressable by the CPU, such as NOR flash. This saves RAM
745 space since the text section of the kernel is not loaded from flash
746 to RAM. Read-write sections, such as the data section and stack,
747 are still copied to RAM. The XIP kernel is not compressed since
748 it has to run directly from flash, so it will take more space to
749 store it. The flash address used to link the kernel object files,
750 and for storing it, is configuration dependent. Therefore, if you
751 say Y here, you must know the proper physical address where to
752 store the kernel image depending on your own flash memory usage.
754 Also note that the make target becomes "make xipImage" rather than
755 "make zImage" or "make Image". The final kernel binary to put in
756 ROM memory will be arch/riscv/boot/xipImage.
758 SPARSEMEM is required because the kernel text and rodata that are
759 flash resident are not backed by memmap, then any attempt to get
760 a struct page on those regions will trigger a fault.
765 hex "XIP Kernel Physical Location"
766 depends on XIP_KERNEL
769 This is the physical address in your flash memory the kernel will
770 be linked for and stored to. This address is dependent on your
773 endmenu # "Boot options"
777 depends on OF && NONPORTABLE
778 default y if XIP_KERNEL
787 menu "Power management options"
789 source "kernel/power/Kconfig"
791 endmenu # "Power management options"
793 menu "CPU Power Management"
795 source "drivers/cpuidle/Kconfig"
797 source "drivers/cpufreq/Kconfig"
799 endmenu # "CPU Power Management"
801 source "arch/riscv/kvm/Kconfig"