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 ARCH_DMA_DEFAULT_COHERENT 16 select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION 17 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 18 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE 19 select ARCH_HAS_BINFMT_FLAT 20 select ARCH_HAS_CURRENT_STACK_POINTER 21 select ARCH_HAS_DEBUG_VIRTUAL if MMU 22 select ARCH_HAS_DEBUG_VM_PGTABLE 23 select ARCH_HAS_DEBUG_WX 24 select ARCH_HAS_FORTIFY_SOURCE 25 select ARCH_HAS_GCOV_PROFILE_ALL 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_HAS_KCOV 28 select ARCH_HAS_MMIOWB 29 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 30 select ARCH_HAS_PMEM_API 31 select ARCH_HAS_PTE_SPECIAL 32 select ARCH_HAS_SET_DIRECT_MAP if MMU 33 select ARCH_HAS_SET_MEMORY if MMU 34 select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL 35 select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL 36 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST 37 select ARCH_HAS_UBSAN_SANITIZE_ALL 38 select ARCH_HAS_VDSO_DATA 39 select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX 40 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 41 select ARCH_STACKWALK 42 select ARCH_SUPPORTS_ATOMIC_RMW 43 select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU 44 select ARCH_SUPPORTS_HUGETLBFS if MMU 45 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU 46 select ARCH_USE_MEMTEST 47 select ARCH_USE_QUEUED_RWLOCKS 48 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU 49 select ARCH_WANT_FRAME_POINTERS 50 select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT 51 select ARCH_WANT_HUGE_PMD_SHARE if 64BIT 52 select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL 53 select ARCH_WANT_OPTIMIZE_VMEMMAP 54 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE 55 select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU 56 select BUILDTIME_TABLE_SORT if MMU 57 select CLINT_TIMER if !MMU 58 select CLONE_BACKWARDS 59 select COMMON_CLK 60 select CPU_PM if CPU_IDLE || HIBERNATION 61 select EDAC_SUPPORT 62 select GENERIC_ARCH_TOPOLOGY 63 select GENERIC_ATOMIC64 if !64BIT 64 select GENERIC_CLOCKEVENTS_BROADCAST if SMP 65 select GENERIC_EARLY_IOREMAP 66 select GENERIC_ENTRY 67 select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO 68 select GENERIC_IDLE_POLL_SETUP 69 select GENERIC_IOREMAP if MMU 70 select GENERIC_IRQ_IPI if SMP 71 select GENERIC_IRQ_IPI_MUX if SMP 72 select GENERIC_IRQ_MULTI_HANDLER 73 select GENERIC_IRQ_SHOW 74 select GENERIC_IRQ_SHOW_LEVEL 75 select GENERIC_LIB_DEVMEM_IS_ALLOWED 76 select GENERIC_PCI_IOMAP 77 select GENERIC_PTDUMP if MMU 78 select GENERIC_SCHED_CLOCK 79 select GENERIC_SMP_IDLE_THREAD 80 select GENERIC_TIME_VSYSCALL if MMU && 64BIT 81 select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO 82 select HARDIRQS_SW_RESEND 83 select HAS_IOPORT if MMU 84 select HAVE_ARCH_AUDITSYSCALL 85 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP 86 select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT && !XIP_KERNEL 87 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL 88 select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL 89 select HAVE_ARCH_KASAN if MMU && 64BIT 90 select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT 91 select HAVE_ARCH_KFENCE if MMU && 64BIT 92 select HAVE_ARCH_KGDB if !XIP_KERNEL 93 select HAVE_ARCH_KGDB_QXFER_PKT 94 select HAVE_ARCH_MMAP_RND_BITS if MMU 95 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT 96 select HAVE_ARCH_SECCOMP_FILTER 97 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 98 select HAVE_ARCH_TRACEHOOK 99 select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU 100 select HAVE_ARCH_VMAP_STACK if MMU && 64BIT 101 select HAVE_ASM_MODVERSIONS 102 select HAVE_CONTEXT_TRACKING_USER 103 select HAVE_DEBUG_KMEMLEAK 104 select HAVE_DMA_CONTIGUOUS if MMU 105 select HAVE_EBPF_JIT if MMU 106 select HAVE_FUNCTION_ARG_ACCESS_API 107 select HAVE_FUNCTION_ERROR_INJECTION 108 select HAVE_GCC_PLUGINS 109 select HAVE_GENERIC_VDSO if MMU && 64BIT 110 select HAVE_IRQ_TIME_ACCOUNTING 111 select HAVE_KPROBES if !XIP_KERNEL 112 select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL 113 select HAVE_KRETPROBES if !XIP_KERNEL 114 select HAVE_RETHOOK if !XIP_KERNEL 115 select HAVE_MOVE_PMD 116 select HAVE_MOVE_PUD 117 select HAVE_PCI 118 select HAVE_PERF_EVENTS 119 select HAVE_PERF_REGS 120 select HAVE_PERF_USER_STACK_DUMP 121 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 122 select HAVE_REGS_AND_STACK_ACCESS_API 123 select HAVE_RSEQ 124 select HAVE_STACKPROTECTOR 125 select HAVE_SYSCALL_TRACEPOINTS 126 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU 127 select IRQ_DOMAIN 128 select IRQ_FORCED_THREADING 129 select KASAN_VMALLOC if KASAN 130 select LOCK_MM_AND_FIND_VMA 131 select MODULES_USE_ELF_RELA if MODULES 132 select MODULE_SECTIONS if MODULES 133 select OF 134 select OF_EARLY_FLATTREE 135 select OF_IRQ 136 select PCI_DOMAINS_GENERIC if PCI 137 select PCI_MSI if PCI 138 select RISCV_ALTERNATIVE if !XIP_KERNEL 139 select RISCV_INTC 140 select RISCV_TIMER if RISCV_SBI 141 select SIFIVE_PLIC 142 select SPARSE_IRQ 143 select SYSCTL_EXCEPTION_TRACE 144 select THREAD_INFO_IN_TASK 145 select TRACE_IRQFLAGS_SUPPORT 146 select UACCESS_MEMCPY if !MMU 147 select ZONE_DMA32 if 64BIT 148 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE) 149 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE 150 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL 151 select HAVE_FUNCTION_GRAPH_TRACER 152 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION 153 154config CLANG_SUPPORTS_DYNAMIC_FTRACE 155 def_bool CC_IS_CLANG 156 # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e 157 depends on CLANG_VERSION >= 130000 158 # https://github.com/ClangBuiltLinux/linux/issues/1817 159 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600)) 160 161config GCC_SUPPORTS_DYNAMIC_FTRACE 162 def_bool CC_IS_GCC 163 depends on $(cc-option,-fpatchable-function-entry=8) 164 165config ARCH_MMAP_RND_BITS_MIN 166 default 18 if 64BIT 167 default 8 168 169config ARCH_MMAP_RND_COMPAT_BITS_MIN 170 default 8 171 172# max bits determined by the following formula: 173# VA_BITS - PAGE_SHIFT - 3 174config ARCH_MMAP_RND_BITS_MAX 175 default 24 if 64BIT # SV39 based 176 default 17 177 178config ARCH_MMAP_RND_COMPAT_BITS_MAX 179 default 17 180 181# set if we run in machine mode, cleared if we run in supervisor mode 182config RISCV_M_MODE 183 bool 184 default !MMU 185 186# set if we are running in S-mode and can use SBI calls 187config RISCV_SBI 188 bool 189 depends on !RISCV_M_MODE 190 default y 191 192config MMU 193 bool "MMU-based Paged Memory Management Support" 194 default y 195 help 196 Select if you want MMU-based virtualised addressing space 197 support by paged memory management. If unsure, say 'Y'. 198 199config PAGE_OFFSET 200 hex 201 default 0xC0000000 if 32BIT && MMU 202 default 0x80000000 if !MMU 203 default 0xff60000000000000 if 64BIT 204 205config KASAN_SHADOW_OFFSET 206 hex 207 depends on KASAN_GENERIC 208 default 0xdfffffff00000000 if 64BIT 209 default 0xffffffff if 32BIT 210 211config ARCH_FLATMEM_ENABLE 212 def_bool !NUMA 213 214config ARCH_SPARSEMEM_ENABLE 215 def_bool y 216 depends on MMU 217 select SPARSEMEM_STATIC if 32BIT && SPARSEMEM 218 select SPARSEMEM_VMEMMAP_ENABLE if 64BIT 219 220config ARCH_SELECT_MEMORY_MODEL 221 def_bool ARCH_SPARSEMEM_ENABLE 222 223config ARCH_SUPPORTS_UPROBES 224 def_bool y 225 226config STACKTRACE_SUPPORT 227 def_bool y 228 229config GENERIC_BUG 230 def_bool y 231 depends on BUG 232 select GENERIC_BUG_RELATIVE_POINTERS if 64BIT 233 234config GENERIC_BUG_RELATIVE_POINTERS 235 bool 236 237config GENERIC_CALIBRATE_DELAY 238 def_bool y 239 240config GENERIC_CSUM 241 def_bool y 242 243config GENERIC_HWEIGHT 244 def_bool y 245 246config FIX_EARLYCON_MEM 247 def_bool MMU 248 249config PGTABLE_LEVELS 250 int 251 default 5 if 64BIT 252 default 2 253 254config LOCKDEP_SUPPORT 255 def_bool y 256 257config RISCV_DMA_NONCOHERENT 258 bool 259 select ARCH_HAS_DMA_PREP_COHERENT 260 select ARCH_HAS_SETUP_DMA_OPS 261 select ARCH_HAS_SYNC_DMA_FOR_CPU 262 select ARCH_HAS_SYNC_DMA_FOR_DEVICE 263 select DMA_DIRECT_REMAP 264 265config AS_HAS_INSN 266 def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero) 267 268source "arch/riscv/Kconfig.socs" 269source "arch/riscv/Kconfig.errata" 270 271menu "Platform type" 272 273config NONPORTABLE 274 bool "Allow configurations that result in non-portable kernels" 275 help 276 RISC-V kernel binaries are compatible between all known systems 277 whenever possible, but there are some use cases that can only be 278 satisfied by configurations that result in kernel binaries that are 279 not portable between systems. 280 281 Selecting N does not guarantee kernels will be portable to all known 282 systems. Selecting any of the options guarded by NONPORTABLE will 283 result in kernel binaries that are unlikely to be portable between 284 systems. 285 286 If unsure, say N. 287 288choice 289 prompt "Base ISA" 290 default ARCH_RV64I 291 help 292 This selects the base ISA that this kernel will target and must match 293 the target platform. 294 295config ARCH_RV32I 296 bool "RV32I" 297 depends on NONPORTABLE 298 select 32BIT 299 select GENERIC_LIB_ASHLDI3 300 select GENERIC_LIB_ASHRDI3 301 select GENERIC_LIB_LSHRDI3 302 select GENERIC_LIB_UCMPDI2 303 304config ARCH_RV64I 305 bool "RV64I" 306 select 64BIT 307 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 308 select SWIOTLB if MMU 309 310endchoice 311 312# We must be able to map all physical memory into the kernel, but the compiler 313# is still a bit more efficient when generating code if it's setup in a manner 314# such that it can only map 2GiB of memory. 315choice 316 prompt "Kernel Code Model" 317 default CMODEL_MEDLOW if 32BIT 318 default CMODEL_MEDANY if 64BIT 319 320 config CMODEL_MEDLOW 321 bool "medium low code model" 322 config CMODEL_MEDANY 323 bool "medium any code model" 324endchoice 325 326config MODULE_SECTIONS 327 bool 328 select HAVE_MOD_ARCH_SPECIFIC 329 330config SMP 331 bool "Symmetric Multi-Processing" 332 help 333 This enables support for systems with more than one CPU. If 334 you say N here, the kernel will run on single and 335 multiprocessor machines, but will use only one CPU of a 336 multiprocessor machine. If you say Y here, the kernel will run 337 on many, but not all, single processor machines. On a single 338 processor machine, the kernel will run faster if you say N 339 here. 340 341 If you don't know what to do here, say N. 342 343config SCHED_MC 344 bool "Multi-core scheduler support" 345 depends on SMP 346 help 347 Multi-core scheduler support improves the CPU scheduler's decision 348 making when dealing with multi-core CPU chips at a cost of slightly 349 increased overhead in some places. If unsure say N here. 350 351config NR_CPUS 352 int "Maximum number of CPUs (2-512)" 353 depends on SMP 354 range 2 512 if !RISCV_SBI_V01 355 range 2 32 if RISCV_SBI_V01 && 32BIT 356 range 2 64 if RISCV_SBI_V01 && 64BIT 357 default "32" if 32BIT 358 default "64" if 64BIT 359 360config HOTPLUG_CPU 361 bool "Support for hot-pluggable CPUs" 362 depends on SMP 363 select GENERIC_IRQ_MIGRATION 364 help 365 366 Say Y here to experiment with turning CPUs off and on. CPUs 367 can be controlled through /sys/devices/system/cpu. 368 369 Say N if you want to disable CPU hotplug. 370 371choice 372 prompt "CPU Tuning" 373 default TUNE_GENERIC 374 375config TUNE_GENERIC 376 bool "generic" 377 378endchoice 379 380# Common NUMA Features 381config NUMA 382 bool "NUMA Memory Allocation and Scheduler Support" 383 depends on SMP && MMU 384 select ARCH_SUPPORTS_NUMA_BALANCING 385 select GENERIC_ARCH_NUMA 386 select NEED_PER_CPU_EMBED_FIRST_CHUNK 387 select OF_NUMA 388 select USE_PERCPU_NUMA_NODE_ID 389 help 390 Enable NUMA (Non-Uniform Memory Access) support. 391 392 The kernel will try to allocate memory used by a CPU on the 393 local memory of the CPU and add some more NUMA awareness to the kernel. 394 395config NODES_SHIFT 396 int "Maximum NUMA Nodes (as a power of 2)" 397 range 1 10 398 default "2" 399 depends on NUMA 400 help 401 Specify the maximum number of NUMA Nodes available on the target 402 system. Increases memory reserved to accommodate various tables. 403 404config RISCV_ALTERNATIVE 405 bool 406 depends on !XIP_KERNEL 407 help 408 This Kconfig allows the kernel to automatically patch the 409 erratum or cpufeature required by the execution platform at run 410 time. The code patching overhead is minimal, as it's only done 411 once at boot and once on each module load. 412 413config RISCV_ALTERNATIVE_EARLY 414 bool 415 depends on RISCV_ALTERNATIVE 416 help 417 Allows early patching of the kernel for special errata 418 419config RISCV_ISA_C 420 bool "Emit compressed instructions when building Linux" 421 default y 422 help 423 Adds "C" to the ISA subsets that the toolchain is allowed to emit 424 when building Linux, which results in compressed instructions in the 425 Linux binary. 426 427 If you don't know what to do here, say Y. 428 429config RISCV_ISA_SVNAPOT 430 bool "Svnapot extension support for supervisor mode NAPOT pages" 431 depends on 64BIT && MMU 432 depends on RISCV_ALTERNATIVE 433 default y 434 help 435 Allow kernel to detect the Svnapot ISA-extension dynamically at boot 436 time and enable its usage. 437 438 The Svnapot extension is used to mark contiguous PTEs as a range 439 of contiguous virtual-to-physical translations for a naturally 440 aligned power-of-2 (NAPOT) granularity larger than the base 4KB page 441 size. When HUGETLBFS is also selected this option unconditionally 442 allocates some memory for each NAPOT page size supported by the kernel. 443 When optimizing for low memory consumption and for platforms without 444 the Svnapot extension, it may be better to say N here. 445 446 If you don't know what to do here, say Y. 447 448config RISCV_ISA_SVPBMT 449 bool "Svpbmt extension support for supervisor mode page-based memory types" 450 depends on 64BIT && MMU 451 depends on RISCV_ALTERNATIVE 452 default y 453 help 454 Adds support to dynamically detect the presence of the Svpbmt 455 ISA-extension (Supervisor-mode: page-based memory types) and 456 enable its usage. 457 458 The memory type for a page contains a combination of attributes 459 that indicate the cacheability, idempotency, and ordering 460 properties for access to that page. 461 462 The Svpbmt extension is only available on 64-bit cpus. 463 464 If you don't know what to do here, say Y. 465 466config TOOLCHAIN_HAS_ZBB 467 bool 468 default y 469 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb) 470 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb) 471 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900 472 depends on AS_IS_GNU 473 474config RISCV_ISA_ZBB 475 bool "Zbb extension support for bit manipulation instructions" 476 depends on TOOLCHAIN_HAS_ZBB 477 depends on MMU 478 depends on RISCV_ALTERNATIVE 479 default y 480 help 481 Adds support to dynamically detect the presence of the ZBB 482 extension (basic bit manipulation) and enable its usage. 483 484 The Zbb extension provides instructions to accelerate a number 485 of bit-specific operations (count bit population, sign extending, 486 bitrotation, etc). 487 488 If you don't know what to do here, say Y. 489 490config RISCV_ISA_ZICBOM 491 bool "Zicbom extension support for non-coherent DMA operation" 492 depends on MMU 493 depends on RISCV_ALTERNATIVE 494 default y 495 select RISCV_DMA_NONCOHERENT 496 help 497 Adds support to dynamically detect the presence of the ZICBOM 498 extension (Cache Block Management Operations) and enable its 499 usage. 500 501 The Zicbom extension can be used to handle for example 502 non-coherent DMA support on devices that need it. 503 504 If you don't know what to do here, say Y. 505 506config RISCV_ISA_ZICBOZ 507 bool "Zicboz extension support for faster zeroing of memory" 508 depends on MMU 509 depends on RISCV_ALTERNATIVE 510 default y 511 help 512 Enable the use of the Zicboz extension (cbo.zero instruction) 513 when available. 514 515 The Zicboz extension is used for faster zeroing of memory. 516 517 If you don't know what to do here, say Y. 518 519config TOOLCHAIN_HAS_ZIHINTPAUSE 520 bool 521 default y 522 depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause) 523 depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause) 524 depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600 525 526config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI 527 def_bool y 528 # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc 529 depends on AS_IS_GNU && AS_VERSION >= 23800 530 help 531 Newer binutils versions default to ISA spec version 20191213 which 532 moves some instructions from the I extension to the Zicsr and Zifencei 533 extensions. 534 535config TOOLCHAIN_NEEDS_OLD_ISA_SPEC 536 def_bool y 537 depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI 538 # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16 539 depends on CC_IS_CLANG && CLANG_VERSION < 170000 540 help 541 Certain versions of clang do not support zicsr and zifencei via -march 542 but newer versions of binutils require it for the reasons noted in the 543 help text of CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. This 544 option causes an older ISA spec compatible with these older versions 545 of clang to be passed to GAS, which has the same result as passing zicsr 546 and zifencei to -march. 547 548config FPU 549 bool "FPU support" 550 default y 551 help 552 Say N here if you want to disable all floating-point related procedure 553 in the kernel. 554 555 If you don't know what to do here, say Y. 556 557endmenu # "Platform type" 558 559menu "Kernel features" 560 561source "kernel/Kconfig.hz" 562 563config RISCV_SBI_V01 564 bool "SBI v0.1 support" 565 depends on RISCV_SBI 566 help 567 This config allows kernel to use SBI v0.1 APIs. This will be 568 deprecated in future once legacy M-mode software are no longer in use. 569 570config RISCV_BOOT_SPINWAIT 571 bool "Spinwait booting method" 572 depends on SMP 573 default y if RISCV_SBI_V01 || RISCV_M_MODE 574 help 575 This enables support for booting Linux via spinwait method. In the 576 spinwait method, all cores randomly jump to Linux. One of the cores 577 gets chosen via lottery and all other keep spinning on a percpu 578 variable. This method cannot support CPU hotplug and sparse hartid 579 scheme. It should be only enabled for M-mode Linux or platforms relying 580 on older firmware without SBI HSM extension. All other platforms should 581 rely on ordered booting via SBI HSM extension which gets chosen 582 dynamically at runtime if the firmware supports it. 583 584 Since spinwait is incompatible with sparse hart IDs, it requires 585 NR_CPUS be large enough to contain the physical hart ID of the first 586 hart to enter Linux. 587 588 If unsure what to do here, say N. 589 590config KEXEC 591 bool "Kexec system call" 592 depends on MMU 593 select HOTPLUG_CPU if SMP 594 select KEXEC_CORE 595 help 596 kexec is a system call that implements the ability to shutdown your 597 current kernel, and to start another kernel. It is like a reboot 598 but it is independent of the system firmware. And like a reboot 599 you can start any kernel with it, not just Linux. 600 601 The name comes from the similarity to the exec system call. 602 603config KEXEC_FILE 604 bool "kexec file based systmem call" 605 depends on 64BIT && MMU 606 select HAVE_IMA_KEXEC if IMA 607 select KEXEC_CORE 608 select KEXEC_ELF 609 help 610 This is new version of kexec system call. This system call is 611 file based and takes file descriptors as system call argument 612 for kernel and initramfs as opposed to list of segments as 613 accepted by previous system call. 614 615 If you don't know what to do here, say Y. 616 617config ARCH_HAS_KEXEC_PURGATORY 618 def_bool KEXEC_FILE 619 depends on CRYPTO=y 620 depends on CRYPTO_SHA256=y 621 622config CRASH_DUMP 623 bool "Build kdump crash kernel" 624 help 625 Generate crash dump after being started by kexec. This should 626 be normally only set in special crash dump kernels which are 627 loaded in the main kernel with kexec-tools into a specially 628 reserved region and then later executed after a crash by 629 kdump/kexec. 630 631 For more details see Documentation/admin-guide/kdump/kdump.rst 632 633config COMPAT 634 bool "Kernel support for 32-bit U-mode" 635 default 64BIT 636 depends on 64BIT && MMU 637 help 638 This option enables support for a 32-bit U-mode running under a 64-bit 639 kernel at S-mode. riscv32-specific components such as system calls, 640 the user helper functions (vdso), signal rt_frame functions and the 641 ptrace interface are handled appropriately by the kernel. 642 643 If you want to execute 32-bit userspace applications, say Y. 644 645config RELOCATABLE 646 bool "Build a relocatable kernel" 647 depends on MMU && 64BIT && !XIP_KERNEL 648 help 649 This builds a kernel as a Position Independent Executable (PIE), 650 which retains all relocation metadata required to relocate the 651 kernel binary at runtime to a different virtual address than the 652 address it was linked at. 653 Since RISCV uses the RELA relocation format, this requires a 654 relocation pass at runtime even if the kernel is loaded at the 655 same address it was linked at. 656 657 If unsure, say N. 658 659endmenu # "Kernel features" 660 661menu "Boot options" 662 663config CMDLINE 664 string "Built-in kernel command line" 665 help 666 For most platforms, the arguments for the kernel's command line 667 are provided at run-time, during boot. However, there are cases 668 where either no arguments are being provided or the provided 669 arguments are insufficient or even invalid. 670 671 When that occurs, it is possible to define a built-in command 672 line here and choose how the kernel should use it later on. 673 674choice 675 prompt "Built-in command line usage" if CMDLINE != "" 676 default CMDLINE_FALLBACK 677 help 678 Choose how the kernel will handle the provided built-in command 679 line. 680 681config CMDLINE_FALLBACK 682 bool "Use bootloader kernel arguments if available" 683 help 684 Use the built-in command line as fallback in case we get nothing 685 during boot. This is the default behaviour. 686 687config CMDLINE_EXTEND 688 bool "Extend bootloader kernel arguments" 689 help 690 The command-line arguments provided during boot will be 691 appended to the built-in command line. This is useful in 692 cases where the provided arguments are insufficient and 693 you don't want to or cannot modify them. 694 695config CMDLINE_FORCE 696 bool "Always use the default kernel command string" 697 help 698 Always use the built-in command line, even if we get one during 699 boot. This is useful in case you need to override the provided 700 command line on systems where you don't have or want control 701 over it. 702 703endchoice 704 705config EFI_STUB 706 bool 707 708config EFI 709 bool "UEFI runtime support" 710 depends on OF && !XIP_KERNEL 711 depends on MMU 712 default y 713 select EFI_GENERIC_STUB 714 select EFI_PARAMS_FROM_FDT 715 select EFI_RUNTIME_WRAPPERS 716 select EFI_STUB 717 select LIBFDT 718 select RISCV_ISA_C 719 select UCS2_STRING 720 help 721 This option provides support for runtime services provided 722 by UEFI firmware (such as non-volatile variables, realtime 723 clock, and platform reset). A UEFI stub is also provided to 724 allow the kernel to be booted as an EFI application. This 725 is only useful on systems that have UEFI firmware. 726 727config CC_HAVE_STACKPROTECTOR_TLS 728 def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0) 729 730config STACKPROTECTOR_PER_TASK 731 def_bool y 732 depends on !RANDSTRUCT 733 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS 734 735config PHYS_RAM_BASE_FIXED 736 bool "Explicitly specified physical RAM address" 737 depends on NONPORTABLE 738 default n 739 740config PHYS_RAM_BASE 741 hex "Platform Physical RAM address" 742 depends on PHYS_RAM_BASE_FIXED 743 default "0x80000000" 744 help 745 This is the physical address of RAM in the system. It has to be 746 explicitly specified to run early relocations of read-write data 747 from flash to RAM. 748 749config XIP_KERNEL 750 bool "Kernel Execute-In-Place from ROM" 751 depends on MMU && SPARSEMEM && NONPORTABLE 752 # This prevents XIP from being enabled by all{yes,mod}config, which 753 # fail to build since XIP doesn't support large kernels. 754 depends on !COMPILE_TEST 755 select PHYS_RAM_BASE_FIXED 756 help 757 Execute-In-Place allows the kernel to run from non-volatile storage 758 directly addressable by the CPU, such as NOR flash. This saves RAM 759 space since the text section of the kernel is not loaded from flash 760 to RAM. Read-write sections, such as the data section and stack, 761 are still copied to RAM. The XIP kernel is not compressed since 762 it has to run directly from flash, so it will take more space to 763 store it. The flash address used to link the kernel object files, 764 and for storing it, is configuration dependent. Therefore, if you 765 say Y here, you must know the proper physical address where to 766 store the kernel image depending on your own flash memory usage. 767 768 Also note that the make target becomes "make xipImage" rather than 769 "make zImage" or "make Image". The final kernel binary to put in 770 ROM memory will be arch/riscv/boot/xipImage. 771 772 SPARSEMEM is required because the kernel text and rodata that are 773 flash resident are not backed by memmap, then any attempt to get 774 a struct page on those regions will trigger a fault. 775 776 If unsure, say N. 777 778config XIP_PHYS_ADDR 779 hex "XIP Kernel Physical Location" 780 depends on XIP_KERNEL 781 default "0x21000000" 782 help 783 This is the physical address in your flash memory the kernel will 784 be linked for and stored to. This address is dependent on your 785 own flash usage. 786 787endmenu # "Boot options" 788 789config BUILTIN_DTB 790 bool 791 depends on OF && NONPORTABLE 792 default y if XIP_KERNEL 793 794config PORTABLE 795 bool 796 default !NONPORTABLE 797 select EFI 798 select MMU 799 select OF 800 801menu "Power management options" 802 803source "kernel/power/Kconfig" 804 805# Hibernation is only possible on systems where the SBI implementation has 806# marked its reserved memory as not accessible from, or does not run 807# from the same memory as, Linux 808config ARCH_HIBERNATION_POSSIBLE 809 def_bool NONPORTABLE 810 811config ARCH_HIBERNATION_HEADER 812 def_bool HIBERNATION 813 814endmenu # "Power management options" 815 816menu "CPU Power Management" 817 818source "drivers/cpuidle/Kconfig" 819 820source "drivers/cpufreq/Kconfig" 821 822endmenu # "CPU Power Management" 823 824source "arch/riscv/kvm/Kconfig" 825