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