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_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_USERFAULTFD_MINOR if 64BIT && USERFAULTFD 104 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT 105 select HAVE_ASM_MODVERSIONS 106 select HAVE_CONTEXT_TRACKING_USER 107 select HAVE_DEBUG_KMEMLEAK 108 select HAVE_DMA_CONTIGUOUS if MMU 109 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE) 110 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE 111 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL 112 select HAVE_FUNCTION_GRAPH_TRACER 113 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 114 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION 115 select HAVE_EBPF_JIT if MMU 116 select HAVE_FUNCTION_ARG_ACCESS_API 117 select HAVE_FUNCTION_ERROR_INJECTION 118 select HAVE_GCC_PLUGINS 119 select HAVE_GENERIC_VDSO if MMU && 64BIT 120 select HAVE_IRQ_TIME_ACCOUNTING 121 select HAVE_KPROBES if !XIP_KERNEL 122 select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL 123 select HAVE_KRETPROBES if !XIP_KERNEL 124 # https://github.com/ClangBuiltLinux/linux/issues/1881 125 select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD 126 select HAVE_MOVE_PMD 127 select HAVE_MOVE_PUD 128 select HAVE_PCI 129 select HAVE_PERF_EVENTS 130 select HAVE_PERF_REGS 131 select HAVE_PERF_USER_STACK_DUMP 132 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 133 select HAVE_REGS_AND_STACK_ACCESS_API 134 select HAVE_RETHOOK if !XIP_KERNEL 135 select HAVE_RSEQ 136 select HAVE_STACKPROTECTOR 137 select HAVE_SYSCALL_TRACEPOINTS 138 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU 139 select IRQ_DOMAIN 140 select IRQ_FORCED_THREADING 141 select KASAN_VMALLOC if KASAN 142 select LOCK_MM_AND_FIND_VMA 143 select MODULES_USE_ELF_RELA if MODULES 144 select MODULE_SECTIONS if MODULES 145 select OF 146 select OF_EARLY_FLATTREE 147 select OF_IRQ 148 select PCI_DOMAINS_GENERIC if PCI 149 select PCI_MSI if PCI 150 select RISCV_ALTERNATIVE if !XIP_KERNEL 151 select RISCV_INTC 152 select RISCV_TIMER if RISCV_SBI 153 select SIFIVE_PLIC 154 select SPARSE_IRQ 155 select SYSCTL_EXCEPTION_TRACE 156 select THREAD_INFO_IN_TASK 157 select TRACE_IRQFLAGS_SUPPORT 158 select UACCESS_MEMCPY if !MMU 159 select ZONE_DMA32 if 64BIT 160 161config CLANG_SUPPORTS_DYNAMIC_FTRACE 162 def_bool CC_IS_CLANG 163 # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e 164 depends on CLANG_VERSION >= 130000 165 # https://github.com/ClangBuiltLinux/linux/issues/1817 166 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600)) 167 168config GCC_SUPPORTS_DYNAMIC_FTRACE 169 def_bool CC_IS_GCC 170 depends on $(cc-option,-fpatchable-function-entry=8) 171 172config ARCH_MMAP_RND_BITS_MIN 173 default 18 if 64BIT 174 default 8 175 176config ARCH_MMAP_RND_COMPAT_BITS_MIN 177 default 8 178 179# max bits determined by the following formula: 180# VA_BITS - PAGE_SHIFT - 3 181config ARCH_MMAP_RND_BITS_MAX 182 default 24 if 64BIT # SV39 based 183 default 17 184 185config ARCH_MMAP_RND_COMPAT_BITS_MAX 186 default 17 187 188# set if we run in machine mode, cleared if we run in supervisor mode 189config RISCV_M_MODE 190 bool 191 default !MMU 192 193# set if we are running in S-mode and can use SBI calls 194config RISCV_SBI 195 bool 196 depends on !RISCV_M_MODE 197 default y 198 199config MMU 200 bool "MMU-based Paged Memory Management Support" 201 default y 202 help 203 Select if you want MMU-based virtualised addressing space 204 support by paged memory management. If unsure, say 'Y'. 205 206config PAGE_OFFSET 207 hex 208 default 0xC0000000 if 32BIT && MMU 209 default 0x80000000 if !MMU 210 default 0xff60000000000000 if 64BIT 211 212config KASAN_SHADOW_OFFSET 213 hex 214 depends on KASAN_GENERIC 215 default 0xdfffffff00000000 if 64BIT 216 default 0xffffffff if 32BIT 217 218config ARCH_FLATMEM_ENABLE 219 def_bool !NUMA 220 221config ARCH_SPARSEMEM_ENABLE 222 def_bool y 223 depends on MMU 224 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM 225 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT 226 227config ARCH_SELECT_MEMORY_MODEL 228 def_bool ARCH_SPARSEMEM_ENABLE 229 230config ARCH_SUPPORTS_UPROBES 231 def_bool y 232 233config STACKTRACE_SUPPORT 234 def_bool y 235 236config GENERIC_BUG 237 def_bool y 238 depends on BUG 239 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT 240 241config GENERIC_BUG_RELATIVE_POINTERS 242 bool 243 244config GENERIC_CALIBRATE_DELAY 245 def_bool y 246 247config GENERIC_CSUM 248 def_bool y 249 250config GENERIC_HWEIGHT 251 def_bool y 252 253config FIX_EARLYCON_MEM 254 def_bool MMU 255 256config PGTABLE_LEVELS 257 int 258 default 5 if 64BIT 259 default 2 260 261config LOCKDEP_SUPPORT 262 def_bool y 263 264config RISCV_DMA_NONCOHERENT 265 bool 266 select ARCH_HAS_DMA_PREP_COHERENT 267 select ARCH_HAS_SETUP_DMA_OPS 268 select ARCH_HAS_SYNC_DMA_FOR_CPU 269 select ARCH_HAS_SYNC_DMA_FOR_DEVICE 270 select DMA_DIRECT_REMAP 271 272config AS_HAS_INSN 273 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero) 274 275config AS_HAS_OPTION_ARCH 276 # https://reviews.llvm.org/D123515 277 def_bool y 278 depends on $(as-instr, .option arch$(comma) +m) 279 depends on !$(as-instr, .option arch$(comma) -i) 280 281source "arch/riscv/Kconfig.socs" 282source "arch/riscv/Kconfig.errata" 283 284menu "Platform type" 285 286config NONPORTABLE 287 bool "Allow configurations that result in non-portable kernels" 288 help 289 RISC-V kernel binaries are compatible between all known systems 290 whenever possible, but there are some use cases that can only be 291 satisfied by configurations that result in kernel binaries that are 292 not portable between systems. 293 294 Selecting N does not guarantee kernels will be portable to all known 295 systems. Selecting any of the options guarded by NONPORTABLE will 296 result in kernel binaries that are unlikely to be portable between 297 systems. 298 299 If unsure, say N. 300 301choice 302 prompt "Base ISA" 303 default ARCH_RV64I 304 help 305 This selects the base ISA that this kernel will target and must match 306 the target platform. 307 308config ARCH_RV32I 309 bool "RV32I" 310 depends on NONPORTABLE 311 select 32BIT 312 select GENERIC_LIB_ASHLDI3 313 select GENERIC_LIB_ASHRDI3 314 select GENERIC_LIB_LSHRDI3 315 select GENERIC_LIB_UCMPDI2 316 317config ARCH_RV64I 318 bool "RV64I" 319 select 64BIT 320 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 321 select SWIOTLB if MMU 322 323endchoice 324 325# We must be able to map all physical memory into the kernel, but the compiler 326# is still a bit more efficient when generating code if it's setup in a manner 327# such that it can only map 2GiB of memory. 328choice 329 prompt "Kernel Code Model" 330 default CMODEL_MEDLOW if 32BIT 331 default CMODEL_MEDANY if 64BIT 332 333 config CMODEL_MEDLOW 334 bool "medium low code model" 335 config CMODEL_MEDANY 336 bool "medium any code model" 337endchoice 338 339config MODULE_SECTIONS 340 bool 341 select HAVE_MOD_ARCH_SPECIFIC 342 343config SMP 344 bool "Symmetric Multi-Processing" 345 help 346 This enables support for systems with more than one CPU. If 347 you say N here, the kernel will run on single and 348 multiprocessor machines, but will use only one CPU of a 349 multiprocessor machine. If you say Y here, the kernel will run 350 on many, but not all, single processor machines. On a single 351 processor machine, the kernel will run faster if you say N 352 here. 353 354 If you don't know what to do here, say N. 355 356config SCHED_MC 357 bool "Multi-core scheduler support" 358 depends on SMP 359 help 360 Multi-core scheduler support improves the CPU scheduler's decision 361 making when dealing with multi-core CPU chips at a cost of slightly 362 increased overhead in some places. If unsure say N here. 363 364config NR_CPUS 365 int "Maximum number of CPUs (2-512)" 366 depends on SMP 367 range 2 512 if !RISCV_SBI_V01 368 range 2 32 if RISCV_SBI_V01 && 32BIT 369 range 2 64 if RISCV_SBI_V01 && 64BIT 370 default "32" if 32BIT 371 default "64" if 64BIT 372 373config HOTPLUG_CPU 374 bool "Support for hot-pluggable CPUs" 375 depends on SMP 376 select GENERIC_IRQ_MIGRATION 377 help 378 379 Say Y here to experiment with turning CPUs off and on. CPUs 380 can be controlled through /sys/devices/system/cpu. 381 382 Say N if you want to disable CPU hotplug. 383 384choice 385 prompt "CPU Tuning" 386 default TUNE_GENERIC 387 388config TUNE_GENERIC 389 bool "generic" 390 391endchoice 392 393# Common NUMA Features 394config NUMA 395 bool "NUMA Memory Allocation and Scheduler Support" 396 depends on SMP && MMU 397 select ARCH_SUPPORTS_NUMA_BALANCING 398 select GENERIC_ARCH_NUMA 399 select NEED_PER_CPU_EMBED_FIRST_CHUNK 400 select OF_NUMA 401 select USE_PERCPU_NUMA_NODE_ID 402 help 403 Enable NUMA (Non-Uniform Memory Access) support. 404 405 The kernel will try to allocate memory used by a CPU on the 406 local memory of the CPU and add some more NUMA awareness to the kernel. 407 408config NODES_SHIFT 409 int "Maximum NUMA Nodes (as a power of 2)" 410 range 1 10 411 default "2" 412 depends on NUMA 413 help 414 Specify the maximum number of NUMA Nodes available on the target 415 system. Increases memory reserved to accommodate various tables. 416 417config RISCV_ALTERNATIVE 418 bool 419 depends on !XIP_KERNEL 420 help 421 This Kconfig allows the kernel to automatically patch the 422 erratum or cpufeature required by the execution platform at run 423 time. The code patching overhead is minimal, as it's only done 424 once at boot and once on each module load. 425 426config RISCV_ALTERNATIVE_EARLY 427 bool 428 depends on RISCV_ALTERNATIVE 429 help 430 Allows early patching of the kernel for special errata 431 432config RISCV_ISA_C 433 bool "Emit compressed instructions when building Linux" 434 default y 435 help 436 Adds "C" to the ISA subsets that the toolchain is allowed to emit 437 when building Linux, which results in compressed instructions in the 438 Linux binary. 439 440 If you don't know what to do here, say Y. 441 442config RISCV_ISA_SVNAPOT 443 bool "Svnapot extension support for supervisor mode NAPOT pages" 444 depends on 64BIT && MMU 445 depends on RISCV_ALTERNATIVE 446 default y 447 help 448 Allow kernel to detect the Svnapot ISA-extension dynamically at boot 449 time and enable its usage. 450 451 The Svnapot extension is used to mark contiguous PTEs as a range 452 of contiguous virtual-to-physical translations for a naturally 453 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page 454 size. When HUGETLBFS is also selected this option unconditionally 455 allocates some memory for each NAPOT page size supported by the kernel. 456 When optimizing for low memory consumption and for platforms without 457 the Svnapot extension, it may be better to say N here. 458 459 If you don't know what to do here, say Y. 460 461config RISCV_ISA_SVPBMT 462 bool "Svpbmt extension support for supervisor mode page-based memory types" 463 depends on 64BIT && MMU 464 depends on RISCV_ALTERNATIVE 465 default y 466 help 467 Adds support to dynamically detect the presence of the Svpbmt 468 ISA-extension (Supervisor-mode: page-based memory types) and 469 enable its usage. 470 471 The memory type for a page contains a combination of attributes 472 that indicate the cacheability, idempotency, and ordering 473 properties for access to that page. 474 475 The Svpbmt extension is only available on 64-bit cpus. 476 477 If you don't know what to do here, say Y. 478 479config TOOLCHAIN_HAS_V 480 bool 481 default y 482 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv) 483 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv) 484 depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800 485 depends on AS_HAS_OPTION_ARCH 486 487config RISCV_ISA_V 488 bool "VECTOR extension support" 489 depends on TOOLCHAIN_HAS_V 490 depends on FPU 491 select DYNAMIC_SIGFRAME 492 default y 493 help 494 Say N here if you want to disable all vector related procedure 495 in the kernel. 496 497 If you don't know what to do here, say Y. 498 499config RISCV_ISA_V_DEFAULT_ENABLE 500 bool "Enable userspace Vector by default" 501 depends on RISCV_ISA_V 502 default y 503 help 504 Say Y here if you want to enable Vector in userspace by default. 505 Otherwise, userspace has to make explicit prctl() call to enable 506 Vector, or enable it via the sysctl interface. 507 508 If you don't know what to do here, say Y. 509 510config TOOLCHAIN_HAS_ZBB 511 bool 512 default y 513 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb) 514 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb) 515 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900 516 depends on AS_HAS_OPTION_ARCH 517 518config RISCV_ISA_ZBB 519 bool "Zbb extension support for bit manipulation instructions" 520 depends on TOOLCHAIN_HAS_ZBB 521 depends on MMU 522 depends on RISCV_ALTERNATIVE 523 default y 524 help 525 Adds support to dynamically detect the presence of the ZBB 526 extension (basic bit manipulation) and enable its usage. 527 528 The Zbb extension provides instructions to accelerate a number 529 of bit-specific operations (count bit population, sign extending, 530 bitrotation, etc). 531 532 If you don't know what to do here, say Y. 533 534config RISCV_ISA_ZICBOM 535 bool "Zicbom extension support for non-coherent DMA operation" 536 depends on MMU 537 depends on RISCV_ALTERNATIVE 538 default y 539 select RISCV_DMA_NONCOHERENT 540 help 541 Adds support to dynamically detect the presence of the ZICBOM 542 extension (Cache Block Management Operations) and enable its 543 usage. 544 545 The Zicbom extension can be used to handle for example 546 non-coherent DMA support on devices that need it. 547 548 If you don't know what to do here, say Y. 549 550config RISCV_ISA_ZICBOZ 551 bool "Zicboz extension support for faster zeroing of memory" 552 depends on MMU 553 depends on RISCV_ALTERNATIVE 554 default y 555 help 556 Enable the use of the Zicboz extension (cbo.zero instruction) 557 when available. 558 559 The Zicboz extension is used for faster zeroing of memory. 560 561 If you don't know what to do here, say Y. 562 563config TOOLCHAIN_HAS_ZIHINTPAUSE 564 bool 565 default y 566 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause) 567 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause) 568 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600 569 570config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI 571 def_bool y 572 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc 573 depends on AS_IS_GNU && AS_VERSION >= 23800 574 help 575 Newer binutils versions default to ISA spec version 20191213 which 576 moves some instructions from the I extension to the Zicsr and Zifencei 577 extensions. 578 579config TOOLCHAIN_NEEDS_OLD_ISA_SPEC 580 def_bool y 581 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI 582 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16 583 depends on CC_IS_CLANG && CLANG_VERSION < 170000 584 help 585 Certain versions of clang do not support zicsr and zifencei via -march 586 but newer versions of binutils require it for the reasons noted in the 587 help text of CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. This 588 option causes an older ISA spec compatible with these older versions 589 of clang to be passed to GAS, which has the same result as passing zicsr 590 and zifencei to -march. 591 592config FPU 593 bool "FPU support" 594 default y 595 help 596 Say N here if you want to disable all floating-point related procedure 597 in the kernel. 598 599 If you don't know what to do here, say Y. 600 601config IRQ_STACKS 602 bool "Independent irq & softirq stacks" if EXPERT 603 default y 604 select HAVE_IRQ_EXIT_ON_IRQ_STACK 605 select HAVE_SOFTIRQ_ON_OWN_STACK 606 help 607 Add independent irq & softirq stacks for percpu to prevent kernel stack 608 overflows. We may save some memory footprint by disabling IRQ_STACKS. 609 610config THREAD_SIZE_ORDER 611 int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT 612 range 0 4 613 default 1 if 32BIT && !KASAN 614 default 3 if 64BIT && KASAN 615 default 2 616 help 617 Specify the Pages of thread stack size (from 4KB to 64KB), which also 618 affects irq stack size, which is equal to thread stack size. 619 620endmenu # "Platform type" 621 622menu "Kernel features" 623 624source "kernel/Kconfig.hz" 625 626config RISCV_SBI_V01 627 bool "SBI v0.1 support" 628 depends on RISCV_SBI 629 help 630 This config allows kernel to use SBI v0.1 APIs. This will be 631 deprecated in future once legacy M-mode software are no longer in use. 632 633config RISCV_BOOT_SPINWAIT 634 bool "Spinwait booting method" 635 depends on SMP 636 default y if RISCV_SBI_V01 || RISCV_M_MODE 637 help 638 This enables support for booting Linux via spinwait method. In the 639 spinwait method, all cores randomly jump to Linux. One of the cores 640 gets chosen via lottery and all other keep spinning on a percpu 641 variable. This method cannot support CPU hotplug and sparse hartid 642 scheme. It should be only enabled for M-mode Linux or platforms relying 643 on older firmware without SBI HSM extension. All other platforms should 644 rely on ordered booting via SBI HSM extension which gets chosen 645 dynamically at runtime if the firmware supports it. 646 647 Since spinwait is incompatible with sparse hart IDs, it requires 648 NR_CPUS be large enough to contain the physical hart ID of the first 649 hart to enter Linux. 650 651 If unsure what to do here, say N. 652 653config KEXEC 654 bool "Kexec system call" 655 depends on MMU 656 select HOTPLUG_CPU if SMP 657 select KEXEC_CORE 658 help 659 kexec is a system call that implements the ability to shutdown your 660 current kernel, and to start another kernel. It is like a reboot 661 but it is independent of the system firmware. And like a reboot 662 you can start any kernel with it, not just Linux. 663 664 The name comes from the similarity to the exec system call. 665 666config KEXEC_FILE 667 bool "kexec file based systmem call" 668 depends on 64BIT && MMU 669 select HAVE_IMA_KEXEC if IMA 670 select KEXEC_CORE 671 select KEXEC_ELF 672 help 673 This is new version of kexec system call. This system call is 674 file based and takes file descriptors as system call argument 675 for kernel and initramfs as opposed to list of segments as 676 accepted by previous system call. 677 678 If you don't know what to do here, say Y. 679 680config ARCH_HAS_KEXEC_PURGATORY 681 def_bool KEXEC_FILE 682 depends on CRYPTO=y 683 depends on CRYPTO_SHA256=y 684 685config CRASH_DUMP 686 bool "Build kdump crash kernel" 687 help 688 Generate crash dump after being started by kexec. This should 689 be normally only set in special crash dump kernels which are 690 loaded in the main kernel with kexec-tools into a specially 691 reserved region and then later executed after a crash by 692 kdump/kexec. 693 694 For more details see Documentation/admin-guide/kdump/kdump.rst 695 696config COMPAT 697 bool "Kernel support for 32-bit U-mode" 698 default 64BIT 699 depends on 64BIT && MMU 700 help 701 This option enables support for a 32-bit U-mode running under a 64-bit 702 kernel at S-mode. riscv32-specific components such as system calls, 703 the user helper functions (vdso), signal rt_frame functions and the 704 ptrace interface are handled appropriately by the kernel. 705 706 If you want to execute 32-bit userspace applications, say Y. 707 708config RELOCATABLE 709 bool "Build a relocatable kernel" 710 depends on MMU && 64BIT && !XIP_KERNEL 711 help 712 This builds a kernel as a Position Independent Executable (PIE), 713 which retains all relocation metadata required to relocate the 714 kernel binary at runtime to a different virtual address than the 715 address it was linked at. 716 Since RISCV uses the RELA relocation format, this requires a 717 relocation pass at runtime even if the kernel is loaded at the 718 same address it was linked at. 719 720 If unsure, say N. 721 722endmenu # "Kernel features" 723 724menu "Boot options" 725 726config CMDLINE 727 string "Built-in kernel command line" 728 help 729 For most platforms, the arguments for the kernel's command line 730 are provided at run-time, during boot. However, there are cases 731 where either no arguments are being provided or the provided 732 arguments are insufficient or even invalid. 733 734 When that occurs, it is possible to define a built-in command 735 line here and choose how the kernel should use it later on. 736 737choice 738 prompt "Built-in command line usage" if CMDLINE != "" 739 default CMDLINE_FALLBACK 740 help 741 Choose how the kernel will handle the provided built-in command 742 line. 743 744config CMDLINE_FALLBACK 745 bool "Use bootloader kernel arguments if available" 746 help 747 Use the built-in command line as fallback in case we get nothing 748 during boot. This is the default behaviour. 749 750config CMDLINE_EXTEND 751 bool "Extend bootloader kernel arguments" 752 help 753 The command-line arguments provided during boot will be 754 appended to the built-in command line. This is useful in 755 cases where the provided arguments are insufficient and 756 you don't want to or cannot modify them. 757 758config CMDLINE_FORCE 759 bool "Always use the default kernel command string" 760 help 761 Always use the built-in command line, even if we get one during 762 boot. This is useful in case you need to override the provided 763 command line on systems where you don't have or want control 764 over it. 765 766endchoice 767 768config EFI_STUB 769 bool 770 771config EFI 772 bool "UEFI runtime support" 773 depends on OF && !XIP_KERNEL 774 depends on MMU 775 default y 776 select ARCH_SUPPORTS_ACPI if 64BIT 777 select EFI_GENERIC_STUB 778 select EFI_PARAMS_FROM_FDT 779 select EFI_RUNTIME_WRAPPERS 780 select EFI_STUB 781 select LIBFDT 782 select RISCV_ISA_C 783 select UCS2_STRING 784 help 785 This option provides support for runtime services provided 786 by UEFI firmware (such as non-volatile variables, realtime 787 clock, and platform reset). A UEFI stub is also provided to 788 allow the kernel to be booted as an EFI application. This 789 is only useful on systems that have UEFI firmware. 790 791config CC_HAVE_STACKPROTECTOR_TLS 792 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0) 793 794config STACKPROTECTOR_PER_TASK 795 def_bool y 796 depends on !RANDSTRUCT 797 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS 798 799config PHYS_RAM_BASE_FIXED 800 bool "Explicitly specified physical RAM address" 801 depends on NONPORTABLE 802 default n 803 804config PHYS_RAM_BASE 805 hex "Platform Physical RAM address" 806 depends on PHYS_RAM_BASE_FIXED 807 default "0x80000000" 808 help 809 This is the physical address of RAM in the system. It has to be 810 explicitly specified to run early relocations of read-write data 811 from flash to RAM. 812 813config XIP_KERNEL 814 bool "Kernel Execute-In-Place from ROM" 815 depends on MMU && SPARSEMEM && NONPORTABLE 816 # This prevents XIP from being enabled by all{yes,mod}config, which 817 # fail to build since XIP doesn't support large kernels. 818 depends on !COMPILE_TEST 819 select PHYS_RAM_BASE_FIXED 820 help 821 Execute-In-Place allows the kernel to run from non-volatile storage 822 directly addressable by the CPU, such as NOR flash. This saves RAM 823 space since the text section of the kernel is not loaded from flash 824 to RAM. Read-write sections, such as the data section and stack, 825 are still copied to RAM. The XIP kernel is not compressed since 826 it has to run directly from flash, so it will take more space to 827 store it. The flash address used to link the kernel object files, 828 and for storing it, is configuration dependent. Therefore, if you 829 say Y here, you must know the proper physical address where to 830 store the kernel image depending on your own flash memory usage. 831 832 Also note that the make target becomes "make xipImage" rather than 833 "make zImage" or "make Image". The final kernel binary to put in 834 ROM memory will be arch/riscv/boot/xipImage. 835 836 SPARSEMEM is required because the kernel text and rodata that are 837 flash resident are not backed by memmap, then any attempt to get 838 a struct page on those regions will trigger a fault. 839 840 If unsure, say N. 841 842config XIP_PHYS_ADDR 843 hex "XIP Kernel Physical Location" 844 depends on XIP_KERNEL 845 default "0x21000000" 846 help 847 This is the physical address in your flash memory the kernel will 848 be linked for and stored to. This address is dependent on your 849 own flash usage. 850 851endmenu # "Boot options" 852 853config BUILTIN_DTB 854 bool 855 depends on OF && NONPORTABLE 856 default y if XIP_KERNEL 857 858config PORTABLE 859 bool 860 default !NONPORTABLE 861 select EFI 862 select MMU 863 select OF 864 865menu "Power management options" 866 867source "kernel/power/Kconfig" 868 869# Hibernation is only possible on systems where the SBI implementation has 870# marked its reserved memory as not accessible from, or does not run 871# from the same memory as, Linux 872config ARCH_HIBERNATION_POSSIBLE 873 def_bool NONPORTABLE 874 875config ARCH_HIBERNATION_HEADER 876 def_bool HIBERNATION 877 878config ARCH_SUSPEND_POSSIBLE 879 def_bool y 880 881endmenu # "Power management options" 882 883menu "CPU Power Management" 884 885source "drivers/cpuidle/Kconfig" 886 887source "drivers/cpufreq/Kconfig" 888 889endmenu # "CPU Power Management" 890 891source "arch/riscv/kvm/Kconfig" 892 893source "drivers/acpi/Kconfig" 894