arch/riscv/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 #
   3 # For a description of the syntax of this configuration file,
   4 # see Documentation/kbuild/kconfig-language.rst.
   5 #
   6
   7 config 64BIT
   8         bool
   9
  10 config 32BIT
  11         bool
  12
  13 config RISCV
  14         def_bool y
  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
  29         select ARCH_HAS_KCOV
  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
  43         select ARCH_STACKWALK
  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
  62         select COMMON_CLK
  63         select CPU_PM if CPU_IDLE || HIBERNATION
  64         select EDAC_SUPPORT
  65         select GENERIC_ARCH_TOPOLOGY
  66         select GENERIC_ATOMIC64 if !64BIT
  67         select GENERIC_CLOCKEVENTS_BROADCAST if SMP
  68         select GENERIC_EARLY_IOREMAP
  69         select GENERIC_ENTRY
  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_VMAP_STACK if MMU && 64BIT
 104         select HAVE_ASM_MODVERSIONS
 105         select HAVE_CONTEXT_TRACKING_USER
 106         select HAVE_DEBUG_KMEMLEAK
 107         select HAVE_DMA_CONTIGUOUS if MMU
 108         select HAVE_EBPF_JIT if MMU
 109         select HAVE_FUNCTION_ARG_ACCESS_API
 110         select HAVE_FUNCTION_ERROR_INJECTION
 111         select HAVE_GCC_PLUGINS
 112         select HAVE_GENERIC_VDSO if MMU && 64BIT
 113         select HAVE_IRQ_TIME_ACCOUNTING
 114         select HAVE_KPROBES if !XIP_KERNEL
 115         select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
 116         select HAVE_KRETPROBES if !XIP_KERNEL
 117         select HAVE_RETHOOK if !XIP_KERNEL
 118         select HAVE_MOVE_PMD
 119         select HAVE_MOVE_PUD
 120         select HAVE_PCI
 121         select HAVE_PERF_EVENTS
 122         select HAVE_PERF_REGS
 123         select HAVE_PERF_USER_STACK_DUMP
 124         select HAVE_POSIX_CPU_TIMERS_TASK_WORK
 125         select HAVE_REGS_AND_STACK_ACCESS_API
 126         select HAVE_RSEQ
 127         select HAVE_STACKPROTECTOR
 128         select HAVE_SYSCALL_TRACEPOINTS
 129         select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
 130         select IRQ_DOMAIN
 131         select IRQ_FORCED_THREADING
 132         select KASAN_VMALLOC if KASAN
 133         select LOCK_MM_AND_FIND_VMA
 134         select MODULES_USE_ELF_RELA if MODULES
 135         select MODULE_SECTIONS if MODULES
 136         select OF
 137         select OF_EARLY_FLATTREE
 138         select OF_IRQ
 139         select PCI_DOMAINS_GENERIC if PCI
 140         select PCI_MSI if PCI
 141         select RISCV_ALTERNATIVE if !XIP_KERNEL
 142         select RISCV_INTC
 143         select RISCV_TIMER if RISCV_SBI
 144         select SIFIVE_PLIC
 145         select SPARSE_IRQ
 146         select SYSCTL_EXCEPTION_TRACE
 147         select THREAD_INFO_IN_TASK
 148         select TRACE_IRQFLAGS_SUPPORT
 149         select UACCESS_MEMCPY if !MMU
 150         select ZONE_DMA32 if 64BIT
 151         select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
 152         select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
 153         select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
 154         select HAVE_FUNCTION_GRAPH_TRACER
 155         select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
 156
 157 config CLANG_SUPPORTS_DYNAMIC_FTRACE
 158         def_bool CC_IS_CLANG
 159         # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e
 160         depends on CLANG_VERSION >= 130000
 161         # https://github.com/ClangBuiltLinux/linux/issues/1817
 162         depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
 163
 164 config GCC_SUPPORTS_DYNAMIC_FTRACE
 165         def_bool CC_IS_GCC
 166         depends on $(cc-option,-fpatchable-function-entry=8)
 167
 168 config ARCH_MMAP_RND_BITS_MIN
 169         default 18 if 64BIT
 170         default 8
 171
 172 config ARCH_MMAP_RND_COMPAT_BITS_MIN
 173         default 8
 174
 175 # max bits determined by the following formula:
 176 #  VA_BITS - PAGE_SHIFT - 3
 177 config ARCH_MMAP_RND_BITS_MAX
 178         default 24 if 64BIT # SV39 based
 179         default 17
 180
 181 config ARCH_MMAP_RND_COMPAT_BITS_MAX
 182         default 17
 183
 184 # set if we run in machine mode, cleared if we run in supervisor mode
 185 config RISCV_M_MODE
 186         bool
 187         default !MMU
 188
 189 # set if we are running in S-mode and can use SBI calls
 190 config RISCV_SBI
 191         bool
 192         depends on !RISCV_M_MODE
 193         default y
 194
 195 config MMU
 196         bool "MMU-based Paged Memory Management Support"
 197         default y
 198         help
 199           Select if you want MMU-based virtualised addressing space
 200           support by paged memory management. If unsure, say 'Y'.
 201
 202 config PAGE_OFFSET
 203         hex
 204         default 0xC0000000 if 32BIT && MMU
 205         default 0x80000000 if !MMU
 206         default 0xff60000000000000 if 64BIT
 207
 208 config KASAN_SHADOW_OFFSET
 209         hex
 210         depends on KASAN_GENERIC
 211         default 0xdfffffff00000000 if 64BIT
 212         default 0xffffffff if 32BIT
 213
 214 config ARCH_FLATMEM_ENABLE
 215         def_bool !NUMA
 216
 217 config ARCH_SPARSEMEM_ENABLE
 218         def_bool y
 219         depends on MMU
 220         select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
 221         select SPARSEMEM_VMEMMAP_ENABLE if 64BIT
 222
 223 config ARCH_SELECT_MEMORY_MODEL
 224         def_bool ARCH_SPARSEMEM_ENABLE
 225
 226 config ARCH_SUPPORTS_UPROBES
 227         def_bool y
 228
 229 config STACKTRACE_SUPPORT
 230         def_bool y
 231
 232 config GENERIC_BUG
 233         def_bool y
 234         depends on BUG
 235         select GENERIC_BUG_RELATIVE_POINTERS if 64BIT
 236
 237 config GENERIC_BUG_RELATIVE_POINTERS
 238         bool
 239
 240 config GENERIC_CALIBRATE_DELAY
 241         def_bool y
 242
 243 config GENERIC_CSUM
 244         def_bool y
 245
 246 config GENERIC_HWEIGHT
 247         def_bool y
 248
 249 config FIX_EARLYCON_MEM
 250         def_bool MMU
 251
 252 config PGTABLE_LEVELS
 253         int
 254         default 5 if 64BIT
 255         default 2
 256
 257 config LOCKDEP_SUPPORT
 258         def_bool y
 259
 260 config RISCV_DMA_NONCOHERENT
 261         bool
 262         select ARCH_HAS_DMA_PREP_COHERENT
 263         select ARCH_HAS_SETUP_DMA_OPS
 264         select ARCH_HAS_SYNC_DMA_FOR_CPU
 265         select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 266         select DMA_DIRECT_REMAP
 267
 268 config AS_HAS_INSN
 269         def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
 270
 271 config AS_HAS_OPTION_ARCH
 272         # https://reviews.llvm.org/D123515
 273         def_bool y
 274         depends on $(as-instr, .option arch$(comma) +m)
 275         depends on !$(as-instr, .option arch$(comma) -i)
 276
 277 source "arch/riscv/Kconfig.socs"
 278 source "arch/riscv/Kconfig.errata"
 279
 280 menu "Platform type"
 281
 282 config NONPORTABLE
 283         bool "Allow configurations that result in non-portable kernels"
 284         help
 285           RISC-V kernel binaries are compatible between all known systems
 286           whenever possible, but there are some use cases that can only be
 287           satisfied by configurations that result in kernel binaries that are
 288           not portable between systems.
 289
 290           Selecting N does not guarantee kernels will be portable to all known
 291           systems.  Selecting any of the options guarded by NONPORTABLE will
 292           result in kernel binaries that are unlikely to be portable between
 293           systems.
 294
 295           If unsure, say N.
 296
 297 choice
 298         prompt "Base ISA"
 299         default ARCH_RV64I
 300         help
 301           This selects the base ISA that this kernel will target and must match
 302           the target platform.
 303
 304 config ARCH_RV32I
 305         bool "RV32I"
 306         depends on NONPORTABLE
 307         select 32BIT
 308         select GENERIC_LIB_ASHLDI3
 309         select GENERIC_LIB_ASHRDI3
 310         select GENERIC_LIB_LSHRDI3
 311         select GENERIC_LIB_UCMPDI2
 312
 313 config ARCH_RV64I
 314         bool "RV64I"
 315         select 64BIT
 316         select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
 317         select SWIOTLB if MMU
 318
 319 endchoice
 320
 321 # We must be able to map all physical memory into the kernel, but the compiler
 322 # is still a bit more efficient when generating code if it's setup in a manner
 323 # such that it can only map 2GiB of memory.
 324 choice
 325         prompt "Kernel Code Model"
 326         default CMODEL_MEDLOW if 32BIT
 327         default CMODEL_MEDANY if 64BIT
 328
 329         config CMODEL_MEDLOW
 330                 bool "medium low code model"
 331         config CMODEL_MEDANY
 332                 bool "medium any code model"
 333 endchoice
 334
 335 config MODULE_SECTIONS
 336         bool
 337         select HAVE_MOD_ARCH_SPECIFIC
 338
 339 config SMP
 340         bool "Symmetric Multi-Processing"
 341         help
 342           This enables support for systems with more than one CPU.  If
 343           you say N here, the kernel will run on single and
 344           multiprocessor machines, but will use only one CPU of a
 345           multiprocessor machine. If you say Y here, the kernel will run
 346           on many, but not all, single processor machines. On a single
 347           processor machine, the kernel will run faster if you say N
 348           here.
 349
 350           If you don't know what to do here, say N.
 351
 352 config SCHED_MC
 353         bool "Multi-core scheduler support"
 354         depends on SMP
 355         help
 356           Multi-core scheduler support improves the CPU scheduler's decision
 357           making when dealing with multi-core CPU chips at a cost of slightly
 358           increased overhead in some places. If unsure say N here.
 359
 360 config NR_CPUS
 361         int "Maximum number of CPUs (2-512)"
 362         depends on SMP
 363         range 2 512 if !RISCV_SBI_V01
 364         range 2 32 if RISCV_SBI_V01 && 32BIT
 365         range 2 64 if RISCV_SBI_V01 && 64BIT
 366         default "32" if 32BIT
 367         default "64" if 64BIT
 368
 369 config HOTPLUG_CPU
 370         bool "Support for hot-pluggable CPUs"
 371         depends on SMP
 372         select GENERIC_IRQ_MIGRATION
 373         help
 374
 375           Say Y here to experiment with turning CPUs off and on.  CPUs
 376           can be controlled through /sys/devices/system/cpu.
 377
 378           Say N if you want to disable CPU hotplug.
 379
 380 choice
 381         prompt "CPU Tuning"
 382         default TUNE_GENERIC
 383
 384 config TUNE_GENERIC
 385         bool "generic"
 386
 387 endchoice
 388
 389 # Common NUMA Features
 390 config NUMA
 391         bool "NUMA Memory Allocation and Scheduler Support"
 392         depends on SMP && MMU
 393         select ARCH_SUPPORTS_NUMA_BALANCING
 394         select GENERIC_ARCH_NUMA
 395         select NEED_PER_CPU_EMBED_FIRST_CHUNK
 396         select OF_NUMA
 397         select USE_PERCPU_NUMA_NODE_ID
 398         help
 399           Enable NUMA (Non-Uniform Memory Access) support.
 400
 401           The kernel will try to allocate memory used by a CPU on the
 402           local memory of the CPU and add some more NUMA awareness to the kernel.
 403
 404 config NODES_SHIFT
 405         int "Maximum NUMA Nodes (as a power of 2)"
 406         range 1 10
 407         default "2"
 408         depends on NUMA
 409         help
 410           Specify the maximum number of NUMA Nodes available on the target
 411           system.  Increases memory reserved to accommodate various tables.
 412
 413 config RISCV_ALTERNATIVE
 414         bool
 415         depends on !XIP_KERNEL
 416         help
 417           This Kconfig allows the kernel to automatically patch the
 418           erratum or cpufeature required by the execution platform at run
 419           time. The code patching overhead is minimal, as it's only done
 420           once at boot and once on each module load.
 421
 422 config RISCV_ALTERNATIVE_EARLY
 423         bool
 424         depends on RISCV_ALTERNATIVE
 425         help
 426           Allows early patching of the kernel for special errata
 427
 428 config RISCV_ISA_C
 429         bool "Emit compressed instructions when building Linux"
 430         default y
 431         help
 432           Adds "C" to the ISA subsets that the toolchain is allowed to emit
 433           when building Linux, which results in compressed instructions in the
 434           Linux binary.
 435
 436           If you don't know what to do here, say Y.
 437
 438 config RISCV_ISA_SVNAPOT
 439         bool "Svnapot extension support for supervisor mode NAPOT pages"
 440         depends on 64BIT && MMU
 441         depends on RISCV_ALTERNATIVE
 442         default y
 443         help
 444           Allow kernel to detect the Svnapot ISA-extension dynamically at boot
 445           time and enable its usage.
 446
 447           The Svnapot extension is used to mark contiguous PTEs as a range
 448           of contiguous virtual-to-physical translations for a naturally
 449           aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
 450           size. When HUGETLBFS is also selected this option unconditionally
 451           allocates some memory for each NAPOT page size supported by the kernel.
 452           When optimizing for low memory consumption and for platforms without
 453           the Svnapot extension, it may be better to say N here.
 454
 455           If you don't know what to do here, say Y.
 456
 457 config RISCV_ISA_SVPBMT
 458         bool "Svpbmt extension support for supervisor mode page-based memory types"
 459         depends on 64BIT && MMU
 460         depends on RISCV_ALTERNATIVE
 461         default y
 462         help
 463            Adds support to dynamically detect the presence of the Svpbmt
 464            ISA-extension (Supervisor-mode: page-based memory types) and
 465            enable its usage.
 466
 467            The memory type for a page contains a combination of attributes
 468            that indicate the cacheability, idempotency, and ordering
 469            properties for access to that page.
 470
 471            The Svpbmt extension is only available on 64-bit cpus.
 472
 473            If you don't know what to do here, say Y.
 474
 475 config TOOLCHAIN_HAS_V
 476         bool
 477         default y
 478         depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
 479         depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
 480         depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
 481         depends on AS_HAS_OPTION_ARCH
 482
 483 config RISCV_ISA_V
 484         bool "VECTOR extension support"
 485         depends on TOOLCHAIN_HAS_V
 486         depends on FPU
 487         select DYNAMIC_SIGFRAME
 488         default y
 489         help
 490           Say N here if you want to disable all vector related procedure
 491           in the kernel.
 492
 493           If you don't know what to do here, say Y.
 494
 495 config RISCV_ISA_V_DEFAULT_ENABLE
 496         bool "Enable userspace Vector by default"
 497         depends on RISCV_ISA_V
 498         default y
 499         help
 500           Say Y here if you want to enable Vector in userspace by default.
 501           Otherwise, userspace has to make explicit prctl() call to enable
 502           Vector, or enable it via the sysctl interface.
 503
 504           If you don't know what to do here, say Y.
 505
 506 config TOOLCHAIN_HAS_ZBB
 507         bool
 508         default y
 509         depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
 510         depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
 511         depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
 512         depends on AS_HAS_OPTION_ARCH
 513
 514 config RISCV_ISA_ZBB
 515         bool "Zbb extension support for bit manipulation instructions"
 516         depends on TOOLCHAIN_HAS_ZBB
 517         depends on MMU
 518         depends on RISCV_ALTERNATIVE
 519         default y
 520         help
 521            Adds support to dynamically detect the presence of the ZBB
 522            extension (basic bit manipulation) and enable its usage.
 523
 524            The Zbb extension provides instructions to accelerate a number
 525            of bit-specific operations (count bit population, sign extending,
 526            bitrotation, etc).
 527
 528            If you don't know what to do here, say Y.
 529
 530 config RISCV_ISA_ZICBOM
 531         bool "Zicbom extension support for non-coherent DMA operation"
 532         depends on MMU
 533         depends on RISCV_ALTERNATIVE
 534         default y
 535         select RISCV_DMA_NONCOHERENT
 536         help
 537            Adds support to dynamically detect the presence of the ZICBOM
 538            extension (Cache Block Management Operations) and enable its
 539            usage.
 540
 541            The Zicbom extension can be used to handle for example
 542            non-coherent DMA support on devices that need it.
 543
 544            If you don't know what to do here, say Y.
 545
 546 config RISCV_ISA_ZICBOZ
 547         bool "Zicboz extension support for faster zeroing of memory"
 548         depends on MMU
 549         depends on RISCV_ALTERNATIVE
 550         default y
 551         help
 552            Enable the use of the Zicboz extension (cbo.zero instruction)
 553            when available.
 554
 555            The Zicboz extension is used for faster zeroing of memory.
 556
 557            If you don't know what to do here, say Y.
 558
 559 config TOOLCHAIN_HAS_ZIHINTPAUSE
 560         bool
 561         default y
 562         depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause)
 563         depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause)
 564         depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600
 565
 566 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
 567         def_bool y
 568         # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
 569         depends on AS_IS_GNU && AS_VERSION >= 23800
 570         help
 571           Newer binutils versions default to ISA spec version 20191213 which
 572           moves some instructions from the I extension to the Zicsr and Zifencei
 573           extensions.
 574
 575 config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
 576         def_bool y
 577         depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
 578         # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
 579         depends on CC_IS_CLANG && CLANG_VERSION < 170000
 580         help
 581           Certain versions of clang do not support zicsr and zifencei via -march
 582           but newer versions of binutils require it for the reasons noted in the
 583           help text of CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. This
 584           option causes an older ISA spec compatible with these older versions
 585           of clang to be passed to GAS, which has the same result as passing zicsr
 586           and zifencei to -march.
 587
 588 config FPU
 589         bool "FPU support"
 590         default y
 591         help
 592           Say N here if you want to disable all floating-point related procedure
 593           in the kernel.
 594
 595           If you don't know what to do here, say Y.
 596
 597 config IRQ_STACKS
 598         bool "Independent irq & softirq stacks" if EXPERT
 599         default y
 600         select HAVE_IRQ_EXIT_ON_IRQ_STACK
 601         select HAVE_SOFTIRQ_ON_OWN_STACK
 602         help
 603           Add independent irq & softirq stacks for percpu to prevent kernel stack
 604           overflows. We may save some memory footprint by disabling IRQ_STACKS.
 605
 606 config THREAD_SIZE_ORDER
 607         int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
 608         range 0 4
 609         default 1 if 32BIT && !KASAN
 610         default 3 if 64BIT && KASAN
 611         default 2
 612         help
 613           Specify the Pages of thread stack size (from 4KB to 64KB), which also
 614           affects irq stack size, which is equal to thread stack size.
 615
 616 endmenu # "Platform type"
 617
 618 menu "Kernel features"
 619
 620 source "kernel/Kconfig.hz"
 621
 622 config RISCV_SBI_V01
 623         bool "SBI v0.1 support"
 624         depends on RISCV_SBI
 625         help
 626           This config allows kernel to use SBI v0.1 APIs. This will be
 627           deprecated in future once legacy M-mode software are no longer in use.
 628
 629 config RISCV_BOOT_SPINWAIT
 630         bool "Spinwait booting method"
 631         depends on SMP
 632         default y if RISCV_SBI_V01 || RISCV_M_MODE
 633         help
 634           This enables support for booting Linux via spinwait method. In the
 635           spinwait method, all cores randomly jump to Linux. One of the cores
 636           gets chosen via lottery and all other keep spinning on a percpu
 637           variable. This method cannot support CPU hotplug and sparse hartid
 638           scheme. It should be only enabled for M-mode Linux or platforms relying
 639           on older firmware without SBI HSM extension. All other platforms should
 640           rely on ordered booting via SBI HSM extension which gets chosen
 641           dynamically at runtime if the firmware supports it.
 642
 643           Since spinwait is incompatible with sparse hart IDs, it requires
 644           NR_CPUS be large enough to contain the physical hart ID of the first
 645           hart to enter Linux.
 646
 647           If unsure what to do here, say N.
 648
 649 config KEXEC
 650         bool "Kexec system call"
 651         depends on MMU
 652         select HOTPLUG_CPU if SMP
 653         select KEXEC_CORE
 654         help
 655           kexec is a system call that implements the ability to shutdown your
 656           current kernel, and to start another kernel. It is like a reboot
 657           but it is independent of the system firmware. And like a reboot
 658           you can start any kernel with it, not just Linux.
 659
 660           The name comes from the similarity to the exec system call.
 661
 662 config KEXEC_FILE
 663         bool "kexec file based systmem call"
 664         depends on 64BIT && MMU
 665         select HAVE_IMA_KEXEC if IMA
 666         select KEXEC_CORE
 667         select KEXEC_ELF
 668         help
 669           This is new version of kexec system call. This system call is
 670           file based and takes file descriptors as system call argument
 671           for kernel and initramfs as opposed to list of segments as
 672           accepted by previous system call.
 673
 674           If you don't know what to do here, say Y.
 675
 676 config ARCH_HAS_KEXEC_PURGATORY
 677         def_bool KEXEC_FILE
 678         depends on CRYPTO=y
 679         depends on CRYPTO_SHA256=y
 680
 681 config CRASH_DUMP
 682         bool "Build kdump crash kernel"
 683         help
 684           Generate crash dump after being started by kexec. This should
 685           be normally only set in special crash dump kernels which are
 686           loaded in the main kernel with kexec-tools into a specially
 687           reserved region and then later executed after a crash by
 688           kdump/kexec.
 689
 690           For more details see Documentation/admin-guide/kdump/kdump.rst
 691
 692 config COMPAT
 693         bool "Kernel support for 32-bit U-mode"
 694         default 64BIT
 695         depends on 64BIT && MMU
 696         help
 697           This option enables support for a 32-bit U-mode running under a 64-bit
 698           kernel at S-mode. riscv32-specific components such as system calls,
 699           the user helper functions (vdso), signal rt_frame functions and the
 700           ptrace interface are handled appropriately by the kernel.
 701
 702           If you want to execute 32-bit userspace applications, say Y.
 703
 704 config RELOCATABLE
 705         bool "Build a relocatable kernel"
 706         depends on MMU && 64BIT && !XIP_KERNEL
 707         help
 708           This builds a kernel as a Position Independent Executable (PIE),
 709           which retains all relocation metadata required to relocate the
 710           kernel binary at runtime to a different virtual address than the
 711           address it was linked at.
 712           Since RISCV uses the RELA relocation format, this requires a
 713           relocation pass at runtime even if the kernel is loaded at the
 714           same address it was linked at.
 715
 716           If unsure, say N.
 717
 718 endmenu # "Kernel features"
 719
 720 menu "Boot options"
 721
 722 config CMDLINE
 723         string "Built-in kernel command line"
 724         help
 725           For most platforms, the arguments for the kernel's command line
 726           are provided at run-time, during boot. However, there are cases
 727           where either no arguments are being provided or the provided
 728           arguments are insufficient or even invalid.
 729
 730           When that occurs, it is possible to define a built-in command
 731           line here and choose how the kernel should use it later on.
 732
 733 choice
 734         prompt "Built-in command line usage" if CMDLINE != ""
 735         default CMDLINE_FALLBACK
 736         help
 737           Choose how the kernel will handle the provided built-in command
 738           line.
 739
 740 config CMDLINE_FALLBACK
 741         bool "Use bootloader kernel arguments if available"
 742         help
 743           Use the built-in command line as fallback in case we get nothing
 744           during boot. This is the default behaviour.
 745
 746 config CMDLINE_EXTEND
 747         bool "Extend bootloader kernel arguments"
 748         help
 749           The command-line arguments provided during boot will be
 750           appended to the built-in command line. This is useful in
 751           cases where the provided arguments are insufficient and
 752           you don't want to or cannot modify them.
 753
 754 config CMDLINE_FORCE
 755         bool "Always use the default kernel command string"
 756         help
 757           Always use the built-in command line, even if we get one during
 758           boot. This is useful in case you need to override the provided
 759           command line on systems where you don't have or want control
 760           over it.
 761
 762 endchoice
 763
 764 config EFI_STUB
 765         bool
 766
 767 config EFI
 768         bool "UEFI runtime support"
 769         depends on OF && !XIP_KERNEL
 770         depends on MMU
 771         default y
 772         select ARCH_SUPPORTS_ACPI if 64BIT
 773         select EFI_GENERIC_STUB
 774         select EFI_PARAMS_FROM_FDT
 775         select EFI_RUNTIME_WRAPPERS
 776         select EFI_STUB
 777         select LIBFDT
 778         select RISCV_ISA_C
 779         select UCS2_STRING
 780         help
 781           This option provides support for runtime services provided
 782           by UEFI firmware (such as non-volatile variables, realtime
 783           clock, and platform reset). A UEFI stub is also provided to
 784           allow the kernel to be booted as an EFI application. This
 785           is only useful on systems that have UEFI firmware.
 786
 787 config CC_HAVE_STACKPROTECTOR_TLS
 788         def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
 789
 790 config STACKPROTECTOR_PER_TASK
 791         def_bool y
 792         depends on !RANDSTRUCT
 793         depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
 794
 795 config PHYS_RAM_BASE_FIXED
 796         bool "Explicitly specified physical RAM address"
 797         depends on NONPORTABLE
 798         default n
 799
 800 config PHYS_RAM_BASE
 801         hex "Platform Physical RAM address"
 802         depends on PHYS_RAM_BASE_FIXED
 803         default "0x80000000"
 804         help
 805           This is the physical address of RAM in the system. It has to be
 806           explicitly specified to run early relocations of read-write data
 807           from flash to RAM.
 808
 809 config XIP_KERNEL
 810         bool "Kernel Execute-In-Place from ROM"
 811         depends on MMU && SPARSEMEM && NONPORTABLE
 812         # This prevents XIP from being enabled by all{yes,mod}config, which
 813         # fail to build since XIP doesn't support large kernels.
 814         depends on !COMPILE_TEST
 815         select PHYS_RAM_BASE_FIXED
 816         help
 817           Execute-In-Place allows the kernel to run from non-volatile storage
 818           directly addressable by the CPU, such as NOR flash. This saves RAM
 819           space since the text section of the kernel is not loaded from flash
 820           to RAM.  Read-write sections, such as the data section and stack,
 821           are still copied to RAM.  The XIP kernel is not compressed since
 822           it has to run directly from flash, so it will take more space to
 823           store it.  The flash address used to link the kernel object files,
 824           and for storing it, is configuration dependent. Therefore, if you
 825           say Y here, you must know the proper physical address where to
 826           store the kernel image depending on your own flash memory usage.
 827
 828           Also note that the make target becomes "make xipImage" rather than
 829           "make zImage" or "make Image".  The final kernel binary to put in
 830           ROM memory will be arch/riscv/boot/xipImage.
 831
 832           SPARSEMEM is required because the kernel text and rodata that are
 833           flash resident are not backed by memmap, then any attempt to get
 834           a struct page on those regions will trigger a fault.
 835
 836           If unsure, say N.
 837
 838 config XIP_PHYS_ADDR
 839         hex "XIP Kernel Physical Location"
 840         depends on XIP_KERNEL
 841         default "0x21000000"
 842         help
 843           This is the physical address in your flash memory the kernel will
 844           be linked for and stored to.  This address is dependent on your
 845           own flash usage.
 846
 847 endmenu # "Boot options"
 848
 849 config BUILTIN_DTB
 850         bool
 851         depends on OF && NONPORTABLE
 852         default y if XIP_KERNEL
 853
 854 config PORTABLE
 855         bool
 856         default !NONPORTABLE
 857         select EFI
 858         select MMU
 859         select OF
 860
 861 menu "Power management options"
 862
 863 source "kernel/power/Kconfig"
 864
 865 # Hibernation is only possible on systems where the SBI implementation has
 866 # marked its reserved memory as not accessible from, or does not run
 867 # from the same memory as, Linux
 868 config ARCH_HIBERNATION_POSSIBLE
 869         def_bool NONPORTABLE
 870
 871 config ARCH_HIBERNATION_HEADER
 872         def_bool HIBERNATION
 873
 874 endmenu # "Power management options"
 875
 876 menu "CPU Power Management"
 877
 878 source "drivers/cpuidle/Kconfig"
 879
 880 source "drivers/cpufreq/Kconfig"
 881
 882 endmenu # "CPU Power Management"
 883
 884 source "arch/riscv/kvm/Kconfig"
 885
 886 source "drivers/acpi/Kconfig"