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 7config 64BIT 8 bool 9 10config 32BIT 11 bool 12 13config RISCV 14 def_bool y 15 select ACPI_GENERIC_GSI if ACPI 16 select ACPI_MCFG if (ACPI && PCI) 17 select ACPI_PPTT if ACPI 18 select ACPI_REDUCED_HARDWARE_ONLY if ACPI 19 select ACPI_RIMT if ACPI 20 select ACPI_SPCR_TABLE if ACPI 21 select ARCH_DMA_DEFAULT_COHERENT 22 select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION 23 select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM_VMEMMAP 24 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 25 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE 26 select ARCH_HAS_BINFMT_FLAT 27 select ARCH_HAS_CURRENT_STACK_POINTER 28 select ARCH_HAS_DEBUG_VIRTUAL if MMU 29 select ARCH_HAS_DEBUG_VM_PGTABLE 30 select ARCH_HAS_DEBUG_WX 31 select ARCH_HAS_ELF_CORE_EFLAGS if BINFMT_ELF && ELF_CORE 32 select ARCH_HAS_FAST_MULTIPLIER 33 select ARCH_HAS_FORTIFY_SOURCE 34 select ARCH_HAS_GCOV_PROFILE_ALL 35 select ARCH_HAS_GIGANTIC_PAGE 36 select ARCH_HAS_HW_PTE_YOUNG 37 select ARCH_HAS_KCOV 38 select ARCH_HAS_KERNEL_FPU_SUPPORT if 64BIT && FPU 39 select ARCH_HAS_MEMBARRIER_CALLBACKS 40 select ARCH_HAS_MEMBARRIER_SYNC_CORE 41 select ARCH_HAS_MMIOWB 42 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 43 select ARCH_HAS_PMEM_API 44 select ARCH_HAS_PREEMPT_LAZY 45 select ARCH_HAS_PREPARE_SYNC_CORE_CMD 46 select ARCH_HAS_PTDUMP if MMU 47 select ARCH_HAS_PTE_SPECIAL 48 select ARCH_HAS_SET_DIRECT_MAP if MMU 49 select ARCH_HAS_SET_MEMORY if MMU 50 select ARCH_HAS_STRICT_KERNEL_RWX if MMU 51 select ARCH_HAS_STRICT_MODULE_RWX if MMU 52 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 53 select ARCH_HAS_SYSCALL_WRAPPER 54 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST 55 select ARCH_HAS_UBSAN 56 select ARCH_HAS_VDSO_ARCH_DATA if HAVE_GENERIC_VDSO 57 select ARCH_HAVE_NMI_SAFE_CMPXCHG 58 select ARCH_KEEP_MEMBLOCK if ACPI 59 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE if 64BIT && MMU 60 select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX 61 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 62 select ARCH_STACKWALK 63 select ARCH_SUPPORTS_ATOMIC_RMW 64 select ARCH_SUPPORTS_CFI 65 select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU 66 select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE 67 select ARCH_SUPPORTS_HUGETLBFS if MMU 68 select ARCH_SUPPORTS_LTO_CLANG if CMODEL_MEDANY 69 select ARCH_SUPPORTS_LTO_CLANG_THIN 70 select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS if 64BIT && MMU 71 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU 72 select ARCH_SUPPORTS_PER_VMA_LOCK if MMU 73 select ARCH_SUPPORTS_RT 74 select ARCH_SUPPORTS_SHADOW_CALL_STACK if HAVE_SHADOW_CALL_STACK 75 select ARCH_SUPPORTS_SCHED_MC if SMP 76 select ARCH_USE_CMPXCHG_LOCKREF if 64BIT 77 select ARCH_USE_MEMTEST 78 select ARCH_USE_QUEUED_RWLOCKS 79 select ARCH_USE_SYM_ANNOTATIONS 80 select ARCH_USES_CFI_TRAPS if CFI 81 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if MMU 82 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU 83 select ARCH_WANT_FRAME_POINTERS 84 select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT 85 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT 86 select ARCH_WANT_LD_ORPHAN_WARN 87 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP 88 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP 89 select ARCH_WANTS_NO_INSTR 90 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE 91 select ARCH_WEAK_RELEASE_ACQUIRE if ARCH_USE_QUEUED_SPINLOCKS 92 select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU 93 select BUILDTIME_TABLE_SORT if MMU 94 select CLINT_TIMER if RISCV_M_MODE 95 select CLONE_BACKWARDS 96 select COMMON_CLK 97 select CPU_NO_EFFICIENT_FFS if !RISCV_ISA_ZBB 98 select CPU_PM if CPU_IDLE || HIBERNATION || SUSPEND 99 select DYNAMIC_FTRACE if FUNCTION_TRACER 100 select EDAC_SUPPORT 101 select FRAME_POINTER if PERF_EVENTS || (FUNCTION_TRACER && !DYNAMIC_FTRACE) 102 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if DYNAMIC_FTRACE 103 select FUNCTION_ALIGNMENT_8B if DYNAMIC_FTRACE_WITH_CALL_OPS 104 select GENERIC_ARCH_TOPOLOGY 105 select GENERIC_ATOMIC64 if !64BIT 106 select GENERIC_CLOCKEVENTS_BROADCAST if SMP 107 select GENERIC_CPU_DEVICES 108 select GENERIC_CPU_VULNERABILITIES 109 select GENERIC_EARLY_IOREMAP 110 select GENERIC_ENTRY 111 select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO && 64BIT 112 select GENERIC_IDLE_POLL_SETUP 113 select GENERIC_IOREMAP if MMU 114 select HAVE_IOREMAP_PROT if MMU 115 select GENERIC_IRQ_IPI if SMP 116 select GENERIC_IRQ_IPI_MUX if SMP 117 select GENERIC_IRQ_MULTI_HANDLER 118 select GENERIC_IRQ_SHOW 119 select GENERIC_IRQ_SHOW_LEVEL 120 select GENERIC_LIB_DEVMEM_IS_ALLOWED 121 select GENERIC_PENDING_IRQ if SMP 122 select GENERIC_PCI_IOMAP 123 select GENERIC_SCHED_CLOCK 124 select GENERIC_SMP_IDLE_THREAD 125 select HARDIRQS_SW_RESEND 126 select HAS_IOPORT if MMU 127 select HAVE_ALIGNED_STRUCT_PAGE 128 select HAVE_ARCH_AUDITSYSCALL 129 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP 130 select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT 131 select HAVE_ARCH_JUMP_LABEL 132 select HAVE_ARCH_JUMP_LABEL_RELATIVE 133 select HAVE_ARCH_KASAN if MMU && 64BIT 134 select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT 135 select HAVE_ARCH_KFENCE if MMU && 64BIT 136 select HAVE_ARCH_KSTACK_ERASE 137 select HAVE_ARCH_KGDB 138 select HAVE_ARCH_KGDB_QXFER_PKT 139 select HAVE_ARCH_MMAP_RND_BITS if MMU 140 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT 141 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 142 select HAVE_ARCH_SECCOMP_FILTER 143 select HAVE_ARCH_SOFT_DIRTY if 64BIT && MMU && RISCV_ISA_SVRSW60T59B 144 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 145 select HAVE_ARCH_TRACEHOOK 146 select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU 147 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if 64BIT && MMU 148 select HAVE_ARCH_USERFAULTFD_MINOR if 64BIT && USERFAULTFD 149 select HAVE_ARCH_USERFAULTFD_WP if 64BIT && MMU && USERFAULTFD && RISCV_ISA_SVRSW60T59B 150 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT 151 select HAVE_ASM_MODVERSIONS 152 select HAVE_CONTEXT_TRACKING_USER 153 select HAVE_DEBUG_KMEMLEAK 154 select HAVE_DMA_CONTIGUOUS if MMU 155 select HAVE_DYNAMIC_FTRACE if MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE) 156 select FUNCTION_ALIGNMENT_4B if HAVE_DYNAMIC_FTRACE && RISCV_ISA_C 157 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS if HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS 158 select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS if (DYNAMIC_FTRACE_WITH_ARGS && !CFI) 159 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if HAVE_DYNAMIC_FTRACE 160 select HAVE_FTRACE_GRAPH_FUNC 161 select HAVE_FUNCTION_GRAPH_TRACER if HAVE_DYNAMIC_FTRACE_WITH_ARGS 162 select HAVE_FUNCTION_GRAPH_FREGS 163 select HAVE_FUNCTION_TRACER if HAVE_DYNAMIC_FTRACE 164 select HAVE_EBPF_JIT if MMU 165 select HAVE_GENERIC_TIF_BITS 166 select HAVE_GUP_FAST if MMU 167 select HAVE_FUNCTION_ARG_ACCESS_API 168 select HAVE_FUNCTION_ERROR_INJECTION 169 select HAVE_GCC_PLUGINS 170 select HAVE_GENERIC_VDSO if MMU 171 select HAVE_IRQ_TIME_ACCOUNTING 172 select HAVE_KERNEL_BZIP2 if !EFI_ZBOOT 173 select HAVE_KERNEL_GZIP if !EFI_ZBOOT 174 select HAVE_KERNEL_LZ4 if !EFI_ZBOOT 175 select HAVE_KERNEL_LZMA if !EFI_ZBOOT 176 select HAVE_KERNEL_LZO if !EFI_ZBOOT 177 select HAVE_KERNEL_UNCOMPRESSED if !EFI_ZBOOT 178 select HAVE_KERNEL_ZSTD if !EFI_ZBOOT 179 select HAVE_KERNEL_XZ if !EFI_ZBOOT 180 select HAVE_KPROBES 181 select HAVE_KRETPROBES 182 # https://github.com/ClangBuiltLinux/linux/issues/1881 183 select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD 184 select HAVE_MOVE_PMD 185 select HAVE_MOVE_PUD 186 select HAVE_PAGE_SIZE_4KB 187 select HAVE_PCI 188 select HAVE_PERF_EVENTS 189 select HAVE_PERF_REGS 190 select HAVE_PERF_USER_STACK_DUMP 191 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 192 select HAVE_PREEMPT_DYNAMIC_KEY 193 select HAVE_REGS_AND_STACK_ACCESS_API 194 select HAVE_RETHOOK 195 select HAVE_RSEQ 196 select HAVE_RUST if RUSTC_SUPPORTS_RISCV && CC_IS_CLANG 197 select HAVE_SAMPLE_FTRACE_DIRECT 198 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 199 select HAVE_STACKPROTECTOR 200 select HAVE_SYSCALL_TRACEPOINTS 201 select HOTPLUG_PARALLEL if HOTPLUG_CPU 202 select IRQ_DOMAIN 203 select IRQ_FORCED_THREADING 204 select KASAN_VMALLOC if KASAN 205 select LOCK_MM_AND_FIND_VMA 206 select MMU_GATHER_RCU_TABLE_FREE if SMP && MMU 207 select MODULES_USE_ELF_RELA if MODULES 208 select OF 209 select OF_EARLY_FLATTREE 210 select OF_IRQ 211 select PCI_DOMAINS_GENERIC if PCI 212 select PCI_ECAM if (ACPI && PCI) 213 select PCI_MSI if PCI 214 select RELOCATABLE if !MMU && !PHYS_RAM_BASE_FIXED 215 select RISCV_ALTERNATIVE 216 select RISCV_APLIC 217 select RISCV_IMSIC 218 select RISCV_INTC 219 select RISCV_TIMER if RISCV_SBI 220 select SIFIVE_PLIC 221 select SPARSE_IRQ 222 select SYSCTL_EXCEPTION_TRACE 223 select THREAD_INFO_IN_TASK 224 select TRACE_IRQFLAGS_SUPPORT 225 select UACCESS_MEMCPY if !MMU 226 select VDSO_GETRANDOM if HAVE_GENERIC_VDSO && 64BIT 227 select USER_STACKTRACE_SUPPORT 228 select ZONE_DMA32 if 64BIT 229 230config RUSTC_SUPPORTS_RISCV 231 def_bool y 232 depends on 64BIT 233 234config CLANG_SUPPORTS_DYNAMIC_FTRACE 235 def_bool CC_IS_CLANG 236 # https://github.com/ClangBuiltLinux/linux/issues/1817 237 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600)) 238 239config GCC_SUPPORTS_DYNAMIC_FTRACE 240 def_bool CC_IS_GCC 241 depends on $(cc-option,-fpatchable-function-entry=8) 242 depends on CC_HAS_MIN_FUNCTION_ALIGNMENT || !RISCV_ISA_C 243 244config HAVE_SHADOW_CALL_STACK 245 def_bool $(cc-option,-fsanitize=shadow-call-stack) 246 # https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/a484e843e6eeb51f0cb7b8819e50da6d2444d769 247 depends on $(ld-option,--no-relax-gp) 248 249# https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6 250config ARCH_HAS_BROKEN_DWARF5 251 def_bool y 252 # https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a 253 depends on AS_IS_LLVM && AS_VERSION < 180000 254 # https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77 255 depends on LD_IS_LLD && LLD_VERSION < 180000 256 257config ARCH_MMAP_RND_BITS_MIN 258 default 18 if 64BIT 259 default 8 260 261config ARCH_MMAP_RND_COMPAT_BITS_MIN 262 default 8 263 264# max bits determined by the following formula: 265# VA_BITS - PAGE_SHIFT - 3 266config ARCH_MMAP_RND_BITS_MAX 267 default 24 if 64BIT # SV39 based 268 default 17 269 270config ARCH_MMAP_RND_COMPAT_BITS_MAX 271 default 17 272 273# set if we run in machine mode, cleared if we run in supervisor mode 274config RISCV_M_MODE 275 bool "Build a kernel that runs in machine mode" 276 depends on !MMU 277 default y 278 help 279 Select this option if you want to run the kernel in M-mode, 280 without the assistance of any other firmware. 281 282# set if we are running in S-mode and can use SBI calls 283config RISCV_SBI 284 bool 285 depends on !RISCV_M_MODE 286 default y 287 288config MMU 289 bool "MMU-based Paged Memory Management Support" 290 default y 291 help 292 Select if you want MMU-based virtualised addressing space 293 support by paged memory management. If unsure, say 'Y'. 294 295config KASAN_SHADOW_OFFSET 296 hex 297 depends on KASAN_GENERIC 298 default 0xdfffffff00000000 if 64BIT 299 default 0xffffffff if 32BIT 300 301config ARCH_FLATMEM_ENABLE 302 def_bool !NUMA 303 304config ARCH_SPARSEMEM_ENABLE 305 def_bool y 306 depends on MMU 307 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM 308 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT 309 310config ARCH_SELECT_MEMORY_MODEL 311 def_bool ARCH_SPARSEMEM_ENABLE 312 313config ARCH_SUPPORTS_UPROBES 314 def_bool y 315 316config STACKTRACE_SUPPORT 317 def_bool y 318 319config GENERIC_BUG 320 def_bool y 321 depends on BUG 322 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT 323 324config GENERIC_BUG_RELATIVE_POINTERS 325 bool 326 327config GENERIC_CALIBRATE_DELAY 328 def_bool y 329 330config GENERIC_CSUM 331 def_bool y 332 333config GENERIC_HWEIGHT 334 def_bool y 335 336config FIX_EARLYCON_MEM 337 def_bool MMU 338 339config ILLEGAL_POINTER_VALUE 340 hex 341 default 0 if 32BIT 342 default 0xdead000000000000 if 64BIT 343 344config PGTABLE_LEVELS 345 int 346 default 5 if 64BIT 347 default 2 348 349config LOCKDEP_SUPPORT 350 def_bool y 351 352config RISCV_DMA_NONCOHERENT 353 bool 354 select ARCH_HAS_DMA_PREP_COHERENT 355 select ARCH_HAS_SETUP_DMA_OPS 356 select ARCH_HAS_SYNC_DMA_FOR_CPU 357 select ARCH_HAS_SYNC_DMA_FOR_DEVICE 358 select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB 359 360config RISCV_NONSTANDARD_CACHE_OPS 361 bool 362 help 363 This enables function pointer support for non-standard noncoherent 364 systems to handle cache management. 365 366config AS_HAS_INSN 367 def_bool $(as-instr,.insn 0x100000f) 368 369config AS_HAS_OPTION_ARCH 370 # https://github.com/llvm/llvm-project/commit/9e8ed3403c191ab9c4903e8eeb8f732ff8a43cb4 371 def_bool y 372 depends on $(as-instr, .option arch$(comma) +m) 373 374source "arch/riscv/Kconfig.socs" 375source "arch/riscv/Kconfig.errata" 376 377menu "Platform type" 378 379config NONPORTABLE 380 bool "Allow configurations that result in non-portable kernels" 381 help 382 RISC-V kernel binaries are compatible between all known systems 383 whenever possible, but there are some use cases that can only be 384 satisfied by configurations that result in kernel binaries that are 385 not portable between systems. 386 387 Selecting N does not guarantee kernels will be portable to all known 388 systems. Selecting any of the options guarded by NONPORTABLE will 389 result in kernel binaries that are unlikely to be portable between 390 systems. 391 392 If unsure, say N. 393 394choice 395 prompt "Base ISA" 396 default ARCH_RV64I 397 help 398 This selects the base ISA that this kernel will target and must match 399 the target platform. 400 401config ARCH_RV32I 402 bool "RV32I" 403 depends on NONPORTABLE 404 select 32BIT 405 select GENERIC_LIB_ASHLDI3 406 select GENERIC_LIB_ASHRDI3 407 select GENERIC_LIB_LSHRDI3 408 select GENERIC_LIB_UCMPDI2 409 410config ARCH_RV64I 411 bool "RV64I" 412 select 64BIT 413 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 414 select SWIOTLB if MMU 415 416endchoice 417 418# We must be able to map all physical memory into the kernel, but the compiler 419# is still a bit more efficient when generating code if it's setup in a manner 420# such that it can only map 2GiB of memory. 421choice 422 prompt "Kernel Code Model" 423 default CMODEL_MEDLOW if 32BIT 424 default CMODEL_MEDANY if 64BIT 425 426 config CMODEL_MEDLOW 427 bool "medium low code model" 428 config CMODEL_MEDANY 429 bool "medium any code model" 430endchoice 431 432config MODULE_SECTIONS 433 bool 434 select HAVE_MOD_ARCH_SPECIFIC 435 436config SMP 437 bool "Symmetric Multi-Processing" 438 help 439 This enables support for systems with more than one CPU. If 440 you say N here, the kernel will run on single and 441 multiprocessor machines, but will use only one CPU of a 442 multiprocessor machine. If you say Y here, the kernel will run 443 on many, but not all, single processor machines. On a single 444 processor machine, the kernel will run faster if you say N 445 here. 446 447 If you don't know what to do here, say N. 448 449config NR_CPUS 450 int "Maximum number of CPUs (2-512)" 451 depends on SMP 452 range 2 512 if !RISCV_SBI_V01 453 range 2 32 if RISCV_SBI_V01 && 32BIT 454 range 2 64 if RISCV_SBI_V01 && 64BIT 455 default "32" if 32BIT 456 default "64" if 64BIT 457 458config HOTPLUG_CPU 459 bool "Support for hot-pluggable CPUs" 460 depends on SMP 461 select GENERIC_IRQ_MIGRATION 462 help 463 464 Say Y here to experiment with turning CPUs off and on. CPUs 465 can be controlled through /sys/devices/system/cpu. 466 467 Say N if you want to disable CPU hotplug. 468 469choice 470 prompt "CPU Tuning" 471 default TUNE_GENERIC 472 473config TUNE_GENERIC 474 bool "generic" 475 476endchoice 477 478# Common NUMA Features 479config NUMA 480 bool "NUMA Memory Allocation and Scheduler Support" 481 depends on SMP && MMU 482 select ARCH_SUPPORTS_NUMA_BALANCING 483 select GENERIC_ARCH_NUMA 484 select HAVE_SETUP_PER_CPU_AREA 485 select NEED_PER_CPU_EMBED_FIRST_CHUNK 486 select NEED_PER_CPU_PAGE_FIRST_CHUNK 487 select OF_NUMA 488 select USE_PERCPU_NUMA_NODE_ID 489 help 490 Enable NUMA (Non-Uniform Memory Access) support. 491 492 The kernel will try to allocate memory used by a CPU on the 493 local memory of the CPU and add some more NUMA awareness to the kernel. 494 495config NODES_SHIFT 496 int "Maximum NUMA Nodes (as a power of 2)" 497 range 1 10 498 default "2" 499 depends on NUMA 500 help 501 Specify the maximum number of NUMA Nodes available on the target 502 system. Increases memory reserved to accommodate various tables. 503 504choice 505 prompt "RISC-V spinlock type" 506 default RISCV_COMBO_SPINLOCKS 507 508config RISCV_TICKET_SPINLOCKS 509 bool "Using ticket spinlock" 510 511config RISCV_QUEUED_SPINLOCKS 512 bool "Using queued spinlock" 513 depends on SMP && MMU && NONPORTABLE 514 select ARCH_USE_QUEUED_SPINLOCKS 515 help 516 The queued spinlock implementation requires the forward progress 517 guarantee of cmpxchg()/xchg() atomic operations: CAS with Zabha or 518 LR/SC with Ziccrse provide such guarantee. 519 520 Select this if and only if Zabha or Ziccrse is available on your 521 platform, RISCV_QUEUED_SPINLOCKS must not be selected for platforms 522 without one of those extensions. 523 524 If unsure, select RISCV_COMBO_SPINLOCKS, which will use qspinlocks 525 when supported and otherwise ticket spinlocks. 526 527config RISCV_COMBO_SPINLOCKS 528 bool "Using combo spinlock" 529 depends on SMP && MMU 530 select ARCH_USE_QUEUED_SPINLOCKS 531 help 532 Embed both queued spinlock and ticket lock so that the spinlock 533 implementation can be chosen at runtime. 534 535endchoice 536 537config RISCV_ALTERNATIVE 538 bool 539 help 540 This Kconfig allows the kernel to automatically patch the 541 erratum or cpufeature required by the execution platform at run 542 time. The code patching overhead is minimal, as it's only done 543 once at boot and once on each module load. 544 545config RISCV_ALTERNATIVE_EARLY 546 bool 547 depends on RISCV_ALTERNATIVE 548 help 549 Allows early patching of the kernel for special errata 550 551config RISCV_ISA_C 552 bool "Emit compressed instructions when building Linux" 553 default y 554 help 555 Adds "C" to the ISA subsets that the toolchain is allowed to emit 556 when building Linux, which results in compressed instructions in the 557 Linux binary. This option produces a kernel that will not run on 558 systems that do not support compressed instructions. 559 560 If you don't know what to do here, say Y. 561 562config RISCV_ISA_SUPM 563 bool "Supm extension for userspace pointer masking" 564 depends on 64BIT 565 default y 566 help 567 Add support for pointer masking in userspace (Supm) when the 568 underlying hardware extension (Smnpm or Ssnpm) is detected at boot. 569 570 If this option is disabled, userspace will be unable to use 571 the prctl(PR_{SET,GET}_TAGGED_ADDR_CTRL) API. 572 573config RISCV_ISA_SVNAPOT 574 bool "Svnapot extension support for supervisor mode NAPOT pages" 575 depends on 64BIT && MMU 576 depends on RISCV_ALTERNATIVE 577 default y 578 help 579 Enable support for the Svnapot ISA-extension when it is detected 580 at boot. 581 582 The Svnapot extension is used to mark contiguous PTEs as a range 583 of contiguous virtual-to-physical translations for a naturally 584 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page 585 size. When HUGETLBFS is also selected this option unconditionally 586 allocates some memory for each NAPOT page size supported by the kernel. 587 When optimizing for low memory consumption and for platforms without 588 the Svnapot extension, it may be better to say N here. 589 590 If you don't know what to do here, say Y. 591 592config RISCV_ISA_SVPBMT 593 bool "Svpbmt extension support for supervisor mode page-based memory types" 594 depends on 64BIT && MMU 595 depends on RISCV_ALTERNATIVE 596 default y 597 help 598 Add support for the Svpbmt ISA-extension (Supervisor-mode: 599 page-based memory types) in the kernel when it is detected at boot. 600 601 The memory type for a page contains a combination of attributes 602 that indicate the cacheability, idempotency, and ordering 603 properties for access to that page. 604 605 The Svpbmt extension is only available on 64-bit cpus. 606 607 If you don't know what to do here, say Y. 608 609config TOOLCHAIN_HAS_V 610 bool 611 default y 612 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64imv) 613 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32imv) 614 depends on LD_IS_LLD || LD_VERSION >= 23800 615 depends on AS_HAS_OPTION_ARCH 616 617config RISCV_ISA_V 618 bool "Vector extension support" 619 depends on TOOLCHAIN_HAS_V 620 depends on FPU 621 select DYNAMIC_SIGFRAME 622 default y 623 help 624 Add support for the Vector extension when it is detected at boot. 625 When this option is disabled, neither the kernel nor userspace may 626 use vector procedures. 627 628 If you don't know what to do here, say Y. 629 630config RISCV_ISA_V_DEFAULT_ENABLE 631 bool "Enable userspace Vector by default" 632 depends on RISCV_ISA_V 633 default y 634 help 635 Say Y here if you want to enable Vector in userspace by default. 636 Otherwise, userspace has to make explicit prctl() call to enable 637 Vector, or enable it via the sysctl interface. 638 639 If you don't know what to do here, say Y. 640 641config RISCV_ISA_V_UCOPY_THRESHOLD 642 int "Threshold size for vectorized user copies" 643 depends on RISCV_ISA_V 644 default 768 645 help 646 Prefer using vectorized copy_to_user()/copy_from_user() when the 647 workload size exceeds this value. 648 649config RISCV_ISA_V_PREEMPTIVE 650 bool "Run kernel-mode Vector with kernel preemption" 651 depends on PREEMPTION 652 depends on RISCV_ISA_V 653 default y 654 help 655 Usually, in-kernel SIMD routines are run with preemption disabled. 656 Functions which invoke long running SIMD thus must yield the core's 657 vector unit to prevent blocking other tasks for too long. 658 659 This config allows the kernel to run SIMD without explicitly disabling 660 preemption. Enabling this config will result in higher memory consumption 661 due to the allocation of per-task's kernel Vector context. 662 663config RISCV_ISA_ZAWRS 664 bool "Zawrs extension support for more efficient busy waiting" 665 depends on RISCV_ALTERNATIVE 666 default y 667 help 668 The Zawrs extension defines instructions to be used in polling loops 669 which allow a hart to enter a low-power state or to trap to the 670 hypervisor while waiting on a store to a memory location. Enable the 671 use of these instructions in the kernel when the Zawrs extension is 672 detected at boot. 673 674config TOOLCHAIN_HAS_ZABHA 675 bool 676 default y 677 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zabha) 678 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zabha) 679 depends on AS_HAS_OPTION_ARCH 680 681config RISCV_ISA_ZABHA 682 bool "Zabha extension support for atomic byte/halfword operations" 683 depends on TOOLCHAIN_HAS_ZABHA 684 depends on RISCV_ALTERNATIVE 685 default y 686 help 687 Enable the use of the Zabha ISA-extension to implement kernel 688 byte/halfword atomic memory operations when it is detected at boot. 689 690 If you don't know what to do here, say Y. 691 692config TOOLCHAIN_HAS_ZACAS 693 bool 694 default y 695 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zacas) 696 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zacas) 697 depends on AS_HAS_OPTION_ARCH 698 699config RISCV_ISA_ZACAS 700 bool "Zacas extension support for atomic CAS" 701 depends on RISCV_ALTERNATIVE 702 default y 703 help 704 Enable the use of the Zacas ISA-extension to implement kernel atomic 705 cmpxchg operations when it is detected at boot. 706 707 If you don't know what to do here, say Y. 708 709config TOOLCHAIN_HAS_ZBB 710 bool 711 default y 712 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb) 713 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb) 714 depends on LD_IS_LLD || LD_VERSION >= 23900 715 depends on AS_HAS_OPTION_ARCH 716 717# This symbol indicates that the toolchain supports all v1.0 vector crypto 718# extensions, including Zvk*, Zvbb, and Zvbc. LLVM added all of these at once. 719# binutils added all except Zvkb, then added Zvkb. So we just check for Zvkb. 720config TOOLCHAIN_HAS_VECTOR_CRYPTO 721 def_bool $(as-instr, .option arch$(comma) +v$(comma) +zvkb) 722 depends on AS_HAS_OPTION_ARCH 723 724config TOOLCHAIN_HAS_ZBA 725 bool 726 default y 727 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zba) 728 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zba) 729 depends on LD_IS_LLD || LD_VERSION >= 23900 730 depends on AS_HAS_OPTION_ARCH 731 732config RISCV_ISA_ZBA 733 bool "Zba extension support for bit manipulation instructions" 734 default y 735 help 736 Add support for enabling optimisations in the kernel when the Zba 737 extension is detected at boot. 738 739 The Zba extension provides instructions to accelerate the generation 740 of addresses that index into arrays of basic data types. 741 742 If you don't know what to do here, say Y. 743 744config RISCV_ISA_ZBB 745 bool "Zbb extension support for bit manipulation instructions" 746 depends on RISCV_ALTERNATIVE 747 default y 748 help 749 Add support for enabling optimisations in the kernel when the 750 Zbb extension is detected at boot. Some optimisations may 751 additionally depend on toolchain support for Zbb. 752 753 The Zbb extension provides instructions to accelerate a number 754 of bit-specific operations (count bit population, sign extending, 755 bitrotation, etc). 756 757 If you don't know what to do here, say Y. 758 759config TOOLCHAIN_HAS_ZBC 760 bool 761 default y 762 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbc) 763 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbc) 764 depends on LD_IS_LLD || LD_VERSION >= 23900 765 depends on AS_HAS_OPTION_ARCH 766 767config RISCV_ISA_ZBC 768 bool "Zbc extension support for carry-less multiplication instructions" 769 depends on TOOLCHAIN_HAS_ZBC 770 depends on MMU 771 depends on RISCV_ALTERNATIVE 772 default y 773 help 774 Adds support to dynamically detect the presence of the Zbc 775 extension (carry-less multiplication) and enable its usage. 776 777 The Zbc extension could accelerate CRC (cyclic redundancy check) 778 calculations. 779 780 If you don't know what to do here, say Y. 781 782config TOOLCHAIN_HAS_ZBKB 783 bool 784 default y 785 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbkb) 786 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbkb) 787 depends on LD_IS_LLD || LD_VERSION >= 23900 788 depends on AS_HAS_OPTION_ARCH 789 790config RISCV_ISA_ZBKB 791 bool "Zbkb extension support for bit manipulation instructions" 792 depends on TOOLCHAIN_HAS_ZBKB 793 depends on RISCV_ALTERNATIVE 794 default y 795 help 796 Adds support to dynamically detect the presence of the ZBKB 797 extension (bit manipulation for cryptography) and enable its usage. 798 799 The Zbkb extension provides instructions to accelerate a number 800 of common cryptography operations (pack, zip, etc). 801 802 If you don't know what to do here, say Y. 803 804config RISCV_ISA_ZICBOM 805 bool "Zicbom extension support for non-coherent DMA operation" 806 depends on MMU 807 depends on RISCV_ALTERNATIVE 808 default y 809 select RISCV_DMA_NONCOHERENT 810 select DMA_DIRECT_REMAP 811 help 812 Add support for the Zicbom extension (Cache Block Management 813 Operations) and enable its use in the kernel when it is detected 814 at boot. 815 816 The Zicbom extension can be used to handle for example 817 non-coherent DMA support on devices that need it. 818 819 If you don't know what to do here, say Y. 820 821config RISCV_ISA_ZICBOZ 822 bool "Zicboz extension support for faster zeroing of memory" 823 depends on RISCV_ALTERNATIVE 824 default y 825 help 826 Enable the use of the Zicboz extension (cbo.zero instruction) 827 in the kernel when it is detected at boot. 828 829 The Zicboz extension is used for faster zeroing of memory. 830 831 If you don't know what to do here, say Y. 832 833config RISCV_ISA_ZICBOP 834 bool "Zicbop extension support for cache block prefetch" 835 depends on MMU 836 depends on RISCV_ALTERNATIVE 837 default y 838 help 839 Adds support to dynamically detect the presence of the ZICBOP 840 extension (Cache Block Prefetch Operations) and enable its 841 usage. 842 843 The Zicbop extension can be used to prefetch cache blocks for 844 read/write fetch. 845 846 If you don't know what to do here, say Y. 847 848config RISCV_ISA_SVRSW60T59B 849 bool "Svrsw60t59b extension support for using PTE bits 60 and 59" 850 depends on MMU && 64BIT 851 depends on RISCV_ALTERNATIVE 852 default y 853 help 854 Adds support to dynamically detect the presence of the Svrsw60t59b 855 extension and enable its usage. 856 857 The Svrsw60t59b extension allows to free the PTE reserved bits 60 858 and 59 for software to use. 859 860 If you don't know what to do here, say Y. 861 862config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI 863 def_bool y 864 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc 865 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd 866 depends on AS_IS_GNU && AS_VERSION >= 23600 867 help 868 Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer 869 20191213 version, which moves some instructions from the I extension to 870 the Zicsr and Zifencei extensions. This requires explicitly specifying 871 Zicsr and Zifencei when binutils >= 2.38 or GCC >= 12.1.0. Zicsr 872 and Zifencei are supported in binutils from version 2.36 onwards. 873 To make life easier, and avoid forcing toolchains that default to a 874 newer ISA spec to version 2.2, relax the check to binutils >= 2.36. 875 For GCC < 11.3.0, for which this is not possible or need special 876 treatment, this is dealt with in TOOLCHAIN_NEEDS_OLD_ISA_SPEC. 877 878config TOOLCHAIN_NEEDS_OLD_ISA_SPEC 879 def_bool y 880 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI 881 # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d29f5d6ab513c52fd872f532c492e35ae9fd6671 882 depends on CC_IS_GCC && GCC_VERSION < 110300 883 help 884 Certain versions of GCC do not support zicsr and zifencei via -march. 885 This option causes an older ISA spec compatible with these older 886 versions of GCC to be passed to GAS, which has the same result 887 as passing zicsr and zifencei to -march. 888 889config FPU 890 bool "FPU support" 891 default y 892 help 893 Add support for floating point operations when an FPU is detected at 894 boot. When this option is disabled, neither the kernel nor userspace 895 may use the floating point unit. 896 897 If you don't know what to do here, say Y. 898 899config IRQ_STACKS 900 bool "Independent irq & softirq stacks" if EXPERT 901 default y 902 select HAVE_IRQ_EXIT_ON_IRQ_STACK 903 select HAVE_SOFTIRQ_ON_OWN_STACK 904 help 905 Add independent irq & softirq stacks for percpu to prevent kernel stack 906 overflows. We may save some memory footprint by disabling IRQ_STACKS. 907 908config THREAD_SIZE_ORDER 909 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT 910 range 0 4 911 default 1 if 32BIT 912 default 2 913 help 914 Specify the Pages of thread stack size (from 4KB to 64KB), which also 915 affects irq stack size, which is equal to thread stack size. 916 917config RISCV_MISALIGNED 918 bool 919 help 920 Embed support for detecting and emulating misaligned 921 scalar or vector loads and stores. 922 923config RISCV_SCALAR_MISALIGNED 924 bool 925 select RISCV_MISALIGNED 926 select SYSCTL_ARCH_UNALIGN_ALLOW 927 help 928 Embed support for emulating misaligned loads and stores. 929 930config RISCV_VECTOR_MISALIGNED 931 bool 932 select RISCV_MISALIGNED 933 depends on RISCV_ISA_V 934 help 935 Enable detecting support for vector misaligned loads and stores. 936 937config RISCV_SBI_FWFT_DELEGATE_MISALIGNED 938 bool "Request firmware delegation of unaligned access exceptions" 939 depends on RISCV_SBI 940 depends on NONPORTABLE 941 help 942 Use SBI FWFT to request delegation of load address misaligned and 943 store address misaligned exceptions, if possible, and prefer Linux 944 kernel emulation of these accesses to firmware emulation. 945 946 Unfortunately, Linux's emulation is still incomplete. Namely, it 947 currently does not handle vector instructions and KVM guest accesses. 948 On platforms where these accesses would have been handled by firmware, 949 enabling this causes unexpected kernel oopses, userspaces crashes and 950 KVM guest crashes. If you are sure that these are not a problem for 951 your platform, you can say Y here, which may improve performance. 952 953 Saying N here will not worsen emulation support for unaligned accesses 954 even in the case where the firmware also has incomplete support. It 955 simply keeps the firmware's emulation enabled. 956 957 If you don't know what to do here, say N. 958 959choice 960 prompt "Unaligned Accesses Support" 961 default RISCV_PROBE_UNALIGNED_ACCESS 962 help 963 This determines the level of support for unaligned accesses. This 964 information is used by the kernel to perform optimizations. It is also 965 exposed to user space via the hwprobe syscall. The hardware will be 966 probed at boot by default. 967 968config RISCV_PROBE_UNALIGNED_ACCESS 969 bool "Probe for hardware unaligned access support" 970 select RISCV_SCALAR_MISALIGNED 971 help 972 During boot, the kernel will run a series of tests to determine the 973 speed of unaligned accesses. This probing will dynamically determine 974 the speed of unaligned accesses on the underlying system. If unaligned 975 memory accesses trap into the kernel as they are not supported by the 976 system, the kernel will emulate the unaligned accesses to preserve the 977 UABI. 978 979config RISCV_EMULATED_UNALIGNED_ACCESS 980 bool "Emulate unaligned access where system support is missing" 981 select RISCV_SCALAR_MISALIGNED 982 help 983 If unaligned memory accesses trap into the kernel as they are not 984 supported by the system, the kernel will emulate the unaligned 985 accesses to preserve the UABI. When the underlying system does support 986 unaligned accesses, the unaligned accesses are assumed to be slow. 987 988config RISCV_SLOW_UNALIGNED_ACCESS 989 bool "Assume the system supports slow unaligned memory accesses" 990 depends on NONPORTABLE 991 help 992 Assume that the system supports slow unaligned memory accesses. The 993 kernel and userspace programs may not be able to run at all on systems 994 that do not support unaligned memory accesses. 995 996config RISCV_EFFICIENT_UNALIGNED_ACCESS 997 bool "Assume the system supports fast unaligned memory accesses" 998 depends on NONPORTABLE 999 select DCACHE_WORD_ACCESS if MMU 1000 select HAVE_EFFICIENT_UNALIGNED_ACCESS 1001 help 1002 Assume that the system supports fast unaligned memory accesses. When 1003 enabled, this option improves the performance of the kernel on such 1004 systems. However, the kernel and userspace programs will run much more 1005 slowly, or will not be able to run at all, on systems that do not 1006 support efficient unaligned memory accesses. 1007 1008endchoice 1009 1010choice 1011 prompt "Vector unaligned Accesses Support" 1012 depends on RISCV_ISA_V 1013 default RISCV_PROBE_VECTOR_UNALIGNED_ACCESS 1014 help 1015 This determines the level of support for vector unaligned accesses. This 1016 information is used by the kernel to perform optimizations. It is also 1017 exposed to user space via the hwprobe syscall. The hardware will be 1018 probed at boot by default. 1019 1020config RISCV_PROBE_VECTOR_UNALIGNED_ACCESS 1021 bool "Probe speed of vector unaligned accesses" 1022 select RISCV_VECTOR_MISALIGNED 1023 depends on RISCV_ISA_V 1024 help 1025 During boot, the kernel will run a series of tests to determine the 1026 speed of vector unaligned accesses if they are supported. This probing 1027 will dynamically determine the speed of vector unaligned accesses on 1028 the underlying system if they are supported. 1029 1030config RISCV_SLOW_VECTOR_UNALIGNED_ACCESS 1031 bool "Assume the system supports slow vector unaligned memory accesses" 1032 depends on NONPORTABLE 1033 help 1034 Assume that the system supports slow vector unaligned memory accesses. The 1035 kernel and userspace programs may not be able to run at all on systems 1036 that do not support unaligned memory accesses. 1037 1038config RISCV_EFFICIENT_VECTOR_UNALIGNED_ACCESS 1039 bool "Assume the system supports fast vector unaligned memory accesses" 1040 depends on NONPORTABLE 1041 help 1042 Assume that the system supports fast vector unaligned memory accesses. When 1043 enabled, this option improves the performance of the kernel on such 1044 systems. However, the kernel and userspace programs will run much more 1045 slowly, or will not be able to run at all, on systems that do not 1046 support efficient unaligned memory accesses. 1047 1048endchoice 1049 1050source "arch/riscv/Kconfig.vendor" 1051 1052endmenu # "Platform type" 1053 1054menu "Kernel features" 1055 1056source "kernel/Kconfig.hz" 1057 1058config RISCV_SBI_V01 1059 bool "SBI v0.1 support" 1060 depends on RISCV_SBI 1061 help 1062 This config allows kernel to use SBI v0.1 APIs. This will be 1063 deprecated in future once legacy M-mode software are no longer in use. 1064 1065config RISCV_BOOT_SPINWAIT 1066 bool "Spinwait booting method" 1067 depends on SMP 1068 default y if RISCV_SBI_V01 || RISCV_M_MODE 1069 help 1070 This enables support for booting Linux via spinwait method. In the 1071 spinwait method, all cores randomly jump to Linux. One of the cores 1072 gets chosen via lottery and all other keep spinning on a percpu 1073 variable. This method cannot support CPU hotplug and sparse hartid 1074 scheme. It should be only enabled for M-mode Linux or platforms relying 1075 on older firmware without SBI HSM extension. All other platforms should 1076 rely on ordered booting via SBI HSM extension which gets chosen 1077 dynamically at runtime if the firmware supports it. 1078 1079 Since spinwait is incompatible with sparse hart IDs, it requires 1080 NR_CPUS be large enough to contain the physical hart ID of the first 1081 hart to enter Linux. 1082 1083 If unsure what to do here, say N. 1084 1085config ARCH_SUPPORTS_KEXEC 1086 def_bool y 1087 1088config ARCH_SELECTS_KEXEC 1089 def_bool y 1090 depends on KEXEC 1091 select HOTPLUG_CPU if SMP 1092 1093config ARCH_SUPPORTS_KEXEC_FILE 1094 def_bool 64BIT 1095 1096config ARCH_SELECTS_KEXEC_FILE 1097 def_bool y 1098 depends on KEXEC_FILE 1099 select HAVE_IMA_KEXEC if IMA 1100 select KEXEC_ELF 1101 1102config ARCH_SUPPORTS_KEXEC_PURGATORY 1103 def_bool ARCH_SUPPORTS_KEXEC_FILE 1104 1105config ARCH_SUPPORTS_CRASH_DUMP 1106 def_bool y 1107 1108config ARCH_DEFAULT_CRASH_DUMP 1109 def_bool y 1110 1111config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 1112 def_bool CRASH_RESERVE 1113 1114config COMPAT 1115 bool "Kernel support for 32-bit U-mode" 1116 default 64BIT 1117 depends on 64BIT && MMU 1118 help 1119 This option enables support for a 32-bit U-mode running under a 64-bit 1120 kernel at S-mode. riscv32-specific components such as system calls, 1121 the user helper functions (vdso), signal rt_frame functions and the 1122 ptrace interface are handled appropriately by the kernel. 1123 1124 If you want to execute 32-bit userspace applications, say Y. 1125 1126config PARAVIRT 1127 bool "Enable paravirtualization code" 1128 depends on RISCV_SBI 1129 select HAVE_PV_STEAL_CLOCK_GEN 1130 help 1131 This changes the kernel so it can modify itself when it is run 1132 under a hypervisor, potentially improving performance significantly 1133 over full virtualization. 1134 1135config PARAVIRT_TIME_ACCOUNTING 1136 bool "Paravirtual steal time accounting" 1137 depends on PARAVIRT 1138 help 1139 Select this option to enable fine granularity task steal time 1140 accounting. Time spent executing other tasks in parallel with 1141 the current vCPU is discounted from the vCPU power. To account for 1142 that, there can be a small performance impact. 1143 1144 If in doubt, say N here. 1145 1146config RELOCATABLE 1147 bool "Build a relocatable kernel" 1148 select MODULE_SECTIONS if MODULES 1149 select ARCH_VMLINUX_NEEDS_RELOCS 1150 help 1151 This builds a kernel as a Position Independent Executable (PIE), 1152 which retains all relocation metadata required to relocate the 1153 kernel binary at runtime to a different virtual address than the 1154 address it was linked at. 1155 Since RISCV uses the RELA relocation format, this requires a 1156 relocation pass at runtime even if the kernel is loaded at the 1157 same address it was linked at. 1158 1159 If unsure, say N. 1160 1161config RANDOMIZE_BASE 1162 bool "Randomize the address of the kernel image" 1163 select RELOCATABLE 1164 depends on MMU && 64BIT 1165 help 1166 Randomizes the virtual address at which the kernel image is 1167 loaded, as a security feature that deters exploit attempts 1168 relying on knowledge of the location of kernel internals. 1169 1170 It is the bootloader's job to provide entropy, by passing a 1171 random u64 value in /chosen/kaslr-seed at kernel entry. 1172 1173 When booting via the UEFI stub, it will invoke the firmware's 1174 EFI_RNG_PROTOCOL implementation (if available) to supply entropy 1175 to the kernel proper. In addition, it will randomise the physical 1176 location of the kernel Image as well. 1177 1178 If unsure, say N. 1179 1180config RISCV_USER_CFI 1181 def_bool y 1182 bool "riscv userspace control flow integrity" 1183 depends on 64BIT && MMU && \ 1184 $(cc-option,-mabi=lp64 -march=rv64ima_zicfiss_zicfilp -fcf-protection=full) 1185 depends on RISCV_ALTERNATIVE 1186 select RISCV_SBI 1187 select ARCH_HAS_USER_SHADOW_STACK 1188 select ARCH_USES_HIGH_VMA_FLAGS 1189 select DYNAMIC_SIGFRAME 1190 help 1191 Provides CPU-assisted control flow integrity to userspace tasks. 1192 Control flow integrity is provided by implementing shadow stack for 1193 backward edge and indirect branch tracking for forward edge. 1194 Shadow stack protection is a hardware feature that detects function 1195 return address corruption. This helps mitigate ROP attacks. 1196 Indirect branch tracking enforces that all indirect branches must land 1197 on a landing pad instruction else CPU will fault. This mitigates against 1198 JOP / COP attacks. Applications must be enabled to use it, and old userspace 1199 does not get protection "for free". 1200 default y. 1201 1202endmenu # "Kernel features" 1203 1204menu "Boot options" 1205 1206config CMDLINE 1207 string "Built-in kernel command line" 1208 help 1209 For most platforms, the arguments for the kernel's command line 1210 are provided at run-time, during boot. However, there are cases 1211 where either no arguments are being provided or the provided 1212 arguments are insufficient or even invalid. 1213 1214 When that occurs, it is possible to define a built-in command 1215 line here and choose how the kernel should use it later on. 1216 1217choice 1218 prompt "Built-in command line usage" 1219 depends on CMDLINE != "" 1220 default CMDLINE_FALLBACK 1221 help 1222 Choose how the kernel will handle the provided built-in command 1223 line. 1224 1225config CMDLINE_FALLBACK 1226 bool "Use bootloader kernel arguments if available" 1227 help 1228 Use the built-in command line as fallback in case we get nothing 1229 during boot. This is the default behaviour. 1230 1231config CMDLINE_EXTEND 1232 bool "Extend bootloader kernel arguments" 1233 help 1234 The built-in command line will be appended to the command- 1235 line arguments provided during boot. This is useful in 1236 cases where the provided arguments are insufficient and 1237 you don't want to or cannot modify them. 1238 1239config CMDLINE_FORCE 1240 bool "Always use the default kernel command string" 1241 help 1242 Always use the built-in command line, even if we get one during 1243 boot. This is useful in case you need to override the provided 1244 command line on systems where you don't have or want control 1245 over it. 1246 1247endchoice 1248 1249config EFI_STUB 1250 bool 1251 1252config EFI 1253 bool "UEFI runtime support" 1254 depends on OF 1255 depends on MMU 1256 default y 1257 select ARCH_SUPPORTS_ACPI if 64BIT 1258 select EFI_GENERIC_STUB 1259 select EFI_PARAMS_FROM_FDT 1260 select EFI_RUNTIME_WRAPPERS 1261 select EFI_STUB 1262 select LIBFDT 1263 select RISCV_ISA_C 1264 select UCS2_STRING 1265 help 1266 This option provides support for runtime services provided 1267 by UEFI firmware (such as non-volatile variables, realtime 1268 clock, and platform reset). A UEFI stub is also provided to 1269 allow the kernel to be booted as an EFI application. This 1270 is only useful on systems that have UEFI firmware. 1271 1272config DMI 1273 bool "Enable support for SMBIOS (DMI) tables" 1274 depends on EFI 1275 default y 1276 help 1277 This enables SMBIOS/DMI feature for systems. 1278 1279 This option is only useful on systems that have UEFI firmware. 1280 However, even with this option, the resultant kernel should 1281 continue to boot on existing non-UEFI platforms. 1282 1283config CC_HAVE_STACKPROTECTOR_TLS 1284 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0) 1285 1286config STACKPROTECTOR_PER_TASK 1287 def_bool y 1288 depends on !RANDSTRUCT 1289 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS 1290 1291config PHYS_RAM_BASE_FIXED 1292 bool "Explicitly specified physical RAM address" 1293 depends on NONPORTABLE 1294 default n 1295 1296config PHYS_RAM_BASE 1297 hex "Platform Physical RAM address" 1298 depends on PHYS_RAM_BASE_FIXED 1299 default "0x80000000" 1300 help 1301 This is the physical address of RAM in the system. It has to be 1302 explicitly specified to run early relocations of read-write data 1303 from flash to RAM. 1304 1305config RISCV_ISA_FALLBACK 1306 bool "Permit falling back to parsing riscv,isa for extension support by default" 1307 default y 1308 help 1309 Parsing the "riscv,isa" devicetree property has been deprecated and 1310 replaced by a list of explicitly defined strings. For compatibility 1311 with existing platforms, the kernel will fall back to parsing the 1312 "riscv,isa" property if the replacements are not found. 1313 1314 Selecting N here will result in a kernel that does not use the 1315 fallback, unless the commandline "riscv_isa_fallback" parameter is 1316 present. 1317 1318 Please see the dt-binding, located at 1319 Documentation/devicetree/bindings/riscv/extensions.yaml for details 1320 on the replacement properties, "riscv,isa-base" and 1321 "riscv,isa-extensions". 1322 1323config BUILTIN_DTB 1324 bool "Built-in device tree" 1325 depends on OF && NONPORTABLE 1326 select GENERIC_BUILTIN_DTB 1327 help 1328 Build a device tree into the Linux image. 1329 This option should be selected if no bootloader is being used. 1330 If unsure, say N. 1331 1332 1333config BUILTIN_DTB_NAME 1334 string "Built-in device tree source" 1335 depends on BUILTIN_DTB 1336 help 1337 DTS file path (without suffix, relative to arch/riscv/boot/dts) 1338 for the DTS file that will be used to produce the DTB linked into the 1339 kernel. 1340 1341endmenu # "Boot options" 1342 1343config PORTABLE 1344 bool 1345 default !NONPORTABLE 1346 select EFI 1347 select MMU 1348 select OF 1349 1350config ARCH_PROC_KCORE_TEXT 1351 def_bool y 1352 1353menu "Power management options" 1354 1355source "kernel/power/Kconfig" 1356 1357config ARCH_HIBERNATION_POSSIBLE 1358 def_bool y 1359 1360config ARCH_HIBERNATION_HEADER 1361 def_bool HIBERNATION 1362 1363config ARCH_SUSPEND_POSSIBLE 1364 def_bool y 1365 1366endmenu # "Power management options" 1367 1368menu "CPU Power Management" 1369 1370source "drivers/cpuidle/Kconfig" 1371 1372source "drivers/cpufreq/Kconfig" 1373 1374endmenu # "CPU Power Management" 1375 1376source "arch/riscv/kvm/Kconfig" 1377 1378source "drivers/acpi/Kconfig" 1379