1# SPDX-License-Identifier: GPL-2.0 2config LOONGARCH 3 bool 4 default y 5 select ACPI 6 select ACPI_GENERIC_GSI if ACPI 7 select ACPI_MCFG if ACPI 8 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU 9 select ACPI_PPTT if ACPI 10 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 11 select ARCH_BINFMT_ELF_STATE 12 select ARCH_DISABLE_KASAN_INLINE 13 select ARCH_ENABLE_MEMORY_HOTPLUG 14 select ARCH_ENABLE_MEMORY_HOTREMOVE 15 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE 16 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 17 select ARCH_HAS_CPU_FINALIZE_INIT 18 select ARCH_HAS_CURRENT_STACK_POINTER 19 select ARCH_HAS_DEBUG_VM_PGTABLE 20 select ARCH_HAS_FAST_MULTIPLIER 21 select ARCH_HAS_FORTIFY_SOURCE 22 select ARCH_HAS_KCOV 23 select ARCH_HAS_KERNEL_FPU_SUPPORT if CPU_HAS_FPU 24 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 25 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 26 select ARCH_HAS_PTE_DEVMAP 27 select ARCH_HAS_PTE_SPECIAL 28 select ARCH_HAS_SET_MEMORY 29 select ARCH_HAS_SET_DIRECT_MAP 30 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST 31 select ARCH_INLINE_READ_LOCK if !PREEMPTION 32 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION 33 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION 34 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION 35 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION 36 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION 37 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION 38 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION 39 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION 40 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION 41 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION 42 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION 43 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION 44 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION 45 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION 46 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION 47 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION 48 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION 49 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION 50 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION 51 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION 52 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION 53 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION 54 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION 55 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION 56 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION 57 select ARCH_KEEP_MEMBLOCK 58 select ARCH_MIGHT_HAVE_PC_PARPORT 59 select ARCH_MIGHT_HAVE_PC_SERIO 60 select ARCH_SPARSEMEM_ENABLE 61 select ARCH_STACKWALK 62 select ARCH_SUPPORTS_ACPI 63 select ARCH_SUPPORTS_ATOMIC_RMW 64 select ARCH_SUPPORTS_HUGETLBFS 65 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 66 select ARCH_SUPPORTS_LTO_CLANG 67 select ARCH_SUPPORTS_LTO_CLANG_THIN 68 select ARCH_SUPPORTS_NUMA_BALANCING 69 select ARCH_SUPPORTS_RT 70 select ARCH_USE_BUILTIN_BSWAP 71 select ARCH_USE_CMPXCHG_LOCKREF 72 select ARCH_USE_QUEUED_RWLOCKS 73 select ARCH_USE_QUEUED_SPINLOCKS 74 select ARCH_WANT_DEFAULT_BPF_JIT 75 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 76 select ARCH_WANT_LD_ORPHAN_WARN 77 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP 78 select ARCH_WANTS_NO_INSTR 79 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE 80 select BUILDTIME_TABLE_SORT 81 select COMMON_CLK 82 select CPU_PM 83 select EFI 84 select GENERIC_CLOCKEVENTS 85 select GENERIC_CMOS_UPDATE 86 select GENERIC_CPU_AUTOPROBE 87 select GENERIC_CPU_DEVICES 88 select GENERIC_CPU_VULNERABILITIES 89 select GENERIC_ENTRY 90 select GENERIC_GETTIMEOFDAY 91 select GENERIC_IOREMAP if !ARCH_IOREMAP 92 select GENERIC_IRQ_MATRIX_ALLOCATOR 93 select GENERIC_IRQ_MULTI_HANDLER 94 select GENERIC_IRQ_PROBE 95 select GENERIC_IRQ_SHOW 96 select GENERIC_LIB_ASHLDI3 97 select GENERIC_LIB_ASHRDI3 98 select GENERIC_LIB_CMPDI2 99 select GENERIC_LIB_LSHRDI3 100 select GENERIC_LIB_UCMPDI2 101 select GENERIC_LIB_DEVMEM_IS_ALLOWED 102 select GENERIC_PCI_IOMAP 103 select GENERIC_SCHED_CLOCK 104 select GENERIC_SMP_IDLE_THREAD 105 select GENERIC_TIME_VSYSCALL 106 select GENERIC_VDSO_TIME_NS 107 select GPIOLIB 108 select HAS_IOPORT 109 select HAVE_ARCH_AUDITSYSCALL 110 select HAVE_ARCH_JUMP_LABEL 111 select HAVE_ARCH_JUMP_LABEL_RELATIVE 112 select HAVE_ARCH_KASAN 113 select HAVE_ARCH_KFENCE 114 select HAVE_ARCH_KGDB if PERF_EVENTS 115 select HAVE_ARCH_MMAP_RND_BITS if MMU 116 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 117 select HAVE_ARCH_SECCOMP 118 select HAVE_ARCH_SECCOMP_FILTER 119 select HAVE_ARCH_TRACEHOOK 120 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 121 select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD 122 select HAVE_ASM_MODVERSIONS 123 select HAVE_CONTEXT_TRACKING_USER 124 select HAVE_C_RECORDMCOUNT 125 select HAVE_DEBUG_KMEMLEAK 126 select HAVE_DEBUG_STACKOVERFLOW 127 select HAVE_DMA_CONTIGUOUS 128 select HAVE_DYNAMIC_FTRACE 129 select HAVE_DYNAMIC_FTRACE_WITH_ARGS 130 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 131 select HAVE_DYNAMIC_FTRACE_WITH_REGS 132 select HAVE_EBPF_JIT 133 select HAVE_EFFICIENT_UNALIGNED_ACCESS if !ARCH_STRICT_ALIGN 134 select HAVE_EXIT_THREAD 135 select HAVE_GUP_FAST 136 select HAVE_FTRACE_MCOUNT_RECORD 137 select HAVE_FUNCTION_ARG_ACCESS_API 138 select HAVE_FUNCTION_ERROR_INJECTION 139 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 140 select HAVE_FUNCTION_GRAPH_TRACER 141 select HAVE_FUNCTION_TRACER 142 select HAVE_GCC_PLUGINS 143 select HAVE_GENERIC_VDSO 144 select HAVE_HW_BREAKPOINT if PERF_EVENTS 145 select HAVE_IOREMAP_PROT 146 select HAVE_IRQ_EXIT_ON_IRQ_STACK 147 select HAVE_IRQ_TIME_ACCOUNTING 148 select HAVE_KPROBES 149 select HAVE_KPROBES_ON_FTRACE 150 select HAVE_KRETPROBES 151 select HAVE_LIVEPATCH 152 select HAVE_MOD_ARCH_SPECIFIC 153 select HAVE_NMI 154 select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS && AS_HAS_THIN_ADD_SUB 155 select HAVE_PCI 156 select HAVE_PERF_EVENTS 157 select HAVE_PERF_REGS 158 select HAVE_PERF_USER_STACK_DUMP 159 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 160 select HAVE_PREEMPT_DYNAMIC_KEY 161 select HAVE_REGS_AND_STACK_ACCESS_API 162 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC 163 select HAVE_RETHOOK 164 select HAVE_RSEQ 165 select HAVE_RUST 166 select HAVE_SAMPLE_FTRACE_DIRECT 167 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 168 select HAVE_SETUP_PER_CPU_AREA if NUMA 169 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 170 select HAVE_STACKPROTECTOR 171 select HAVE_SYSCALL_TRACEPOINTS 172 select HAVE_TIF_NOHZ 173 select HAVE_VIRT_CPU_ACCOUNTING_GEN if !SMP 174 select IRQ_FORCED_THREADING 175 select IRQ_LOONGARCH_CPU 176 select LOCK_MM_AND_FIND_VMA 177 select MMU_GATHER_MERGE_VMAS if MMU 178 select MODULES_USE_ELF_RELA if MODULES 179 select NEED_PER_CPU_EMBED_FIRST_CHUNK 180 select NEED_PER_CPU_PAGE_FIRST_CHUNK 181 select OF 182 select OF_EARLY_FLATTREE 183 select PCI 184 select PCI_DOMAINS_GENERIC 185 select PCI_ECAM if ACPI 186 select PCI_LOONGSON 187 select PCI_MSI_ARCH_FALLBACKS 188 select PCI_QUIRKS 189 select PERF_USE_VMALLOC 190 select RTC_LIB 191 select SPARSE_IRQ 192 select SYSCTL_ARCH_UNALIGN_ALLOW 193 select SYSCTL_ARCH_UNALIGN_NO_WARN 194 select SYSCTL_EXCEPTION_TRACE 195 select SWIOTLB 196 select TRACE_IRQFLAGS_SUPPORT 197 select USE_PERCPU_NUMA_NODE_ID 198 select USER_STACKTRACE_SUPPORT 199 select VDSO_GETRANDOM 200 select ZONE_DMA32 201 202config 32BIT 203 bool 204 205config 64BIT 206 def_bool y 207 208config GENERIC_BUG 209 def_bool y 210 depends on BUG 211 212config GENERIC_BUG_RELATIVE_POINTERS 213 def_bool y 214 depends on GENERIC_BUG 215 216config GENERIC_CALIBRATE_DELAY 217 def_bool y 218 219config GENERIC_CSUM 220 def_bool y 221 222config GENERIC_HWEIGHT 223 def_bool y 224 225config L1_CACHE_SHIFT 226 int 227 default "6" 228 229config LOCKDEP_SUPPORT 230 bool 231 default y 232 233config STACKTRACE_SUPPORT 234 bool 235 default y 236 237# MACH_LOONGSON32 and MACH_LOONGSON64 are deliberately carried over from the 238# MIPS Loongson code, to preserve Loongson-specific code paths in drivers that 239# are shared between architectures, and specifically expecting the symbols. 240config MACH_LOONGSON32 241 def_bool 32BIT 242 243config MACH_LOONGSON64 244 def_bool 64BIT 245 246config FIX_EARLYCON_MEM 247 def_bool y 248 249config PGTABLE_2LEVEL 250 bool 251 252config PGTABLE_3LEVEL 253 bool 254 255config PGTABLE_4LEVEL 256 bool 257 258config PGTABLE_LEVELS 259 int 260 default 2 if PGTABLE_2LEVEL 261 default 3 if PGTABLE_3LEVEL 262 default 4 if PGTABLE_4LEVEL 263 264config SCHED_OMIT_FRAME_POINTER 265 bool 266 default y 267 268config AS_HAS_EXPLICIT_RELOCS 269 def_bool $(as-instr,x:pcalau12i \$t0$(comma)%pc_hi20(x)) 270 271config AS_HAS_FCSR_CLASS 272 def_bool $(as-instr,movfcsr2gr \$t0$(comma)\$fcsr0) 273 274config AS_HAS_THIN_ADD_SUB 275 def_bool $(cc-option,-Wa$(comma)-mthin-add-sub) || AS_IS_LLVM 276 277config AS_HAS_LSX_EXTENSION 278 def_bool $(as-instr,vld \$vr0$(comma)\$a0$(comma)0) 279 280config AS_HAS_LASX_EXTENSION 281 def_bool $(as-instr,xvld \$xr0$(comma)\$a0$(comma)0) 282 283config AS_HAS_LBT_EXTENSION 284 def_bool $(as-instr,movscr2gr \$a0$(comma)\$scr0) 285 286config AS_HAS_LVZ_EXTENSION 287 def_bool $(as-instr,hvcl 0) 288 289menu "Kernel type and options" 290 291source "kernel/Kconfig.hz" 292 293choice 294 prompt "Page Table Layout" 295 default 16KB_2LEVEL if 32BIT 296 default 16KB_3LEVEL if 64BIT 297 help 298 Allows choosing the page table layout, which is a combination 299 of page size and page table levels. The size of virtual memory 300 address space are determined by the page table layout. 301 302config 4KB_3LEVEL 303 bool "4KB with 3 levels" 304 select HAVE_PAGE_SIZE_4KB 305 select PGTABLE_3LEVEL 306 help 307 This option selects 4KB page size with 3 level page tables, which 308 support a maximum of 39 bits of application virtual memory. 309 310config 4KB_4LEVEL 311 bool "4KB with 4 levels" 312 select HAVE_PAGE_SIZE_4KB 313 select PGTABLE_4LEVEL 314 help 315 This option selects 4KB page size with 4 level page tables, which 316 support a maximum of 48 bits of application virtual memory. 317 318config 16KB_2LEVEL 319 bool "16KB with 2 levels" 320 select HAVE_PAGE_SIZE_16KB 321 select PGTABLE_2LEVEL 322 help 323 This option selects 16KB page size with 2 level page tables, which 324 support a maximum of 36 bits of application virtual memory. 325 326config 16KB_3LEVEL 327 bool "16KB with 3 levels" 328 select HAVE_PAGE_SIZE_16KB 329 select PGTABLE_3LEVEL 330 help 331 This option selects 16KB page size with 3 level page tables, which 332 support a maximum of 47 bits of application virtual memory. 333 334config 64KB_2LEVEL 335 bool "64KB with 2 levels" 336 select HAVE_PAGE_SIZE_64KB 337 select PGTABLE_2LEVEL 338 help 339 This option selects 64KB page size with 2 level page tables, which 340 support a maximum of 42 bits of application virtual memory. 341 342config 64KB_3LEVEL 343 bool "64KB with 3 levels" 344 select HAVE_PAGE_SIZE_64KB 345 select PGTABLE_3LEVEL 346 help 347 This option selects 64KB page size with 3 level page tables, which 348 support a maximum of 55 bits of application virtual memory. 349 350endchoice 351 352config CMDLINE 353 string "Built-in kernel command line" 354 help 355 For most platforms, the arguments for the kernel's command line 356 are provided at run-time, during boot. However, there are cases 357 where either no arguments are being provided or the provided 358 arguments are insufficient or even invalid. 359 360 When that occurs, it is possible to define a built-in command 361 line here and choose how the kernel should use it later on. 362 363choice 364 prompt "Kernel command line type" 365 default CMDLINE_BOOTLOADER 366 help 367 Choose how the kernel will handle the provided built-in command 368 line. 369 370config CMDLINE_BOOTLOADER 371 bool "Use bootloader kernel arguments if available" 372 help 373 Prefer the command-line passed by the boot loader if available. 374 Use the built-in command line as fallback in case we get nothing 375 during boot. This is the default behaviour. 376 377config CMDLINE_EXTEND 378 bool "Use built-in to extend bootloader kernel arguments" 379 help 380 The command-line arguments provided during boot will be 381 appended to the built-in command line. This is useful in 382 cases where the provided arguments are insufficient and 383 you don't want to or cannot modify them. 384 385config CMDLINE_FORCE 386 bool "Always use the built-in kernel command string" 387 help 388 Always use the built-in command line, even if we get one during 389 boot. This is useful in case you need to override the provided 390 command line on systems where you don't have or want control 391 over it. 392 393endchoice 394 395config BUILTIN_DTB 396 bool "Enable built-in dtb in kernel" 397 depends on OF 398 help 399 Some existing systems do not provide a canonical device tree to 400 the kernel at boot time. Let's provide a device tree table in the 401 kernel, keyed by the dts filename, containing the relevant DTBs. 402 403 Built-in DTBs are generic enough and can be used as references. 404 405config BUILTIN_DTB_NAME 406 string "Source file for built-in dtb" 407 depends on BUILTIN_DTB 408 help 409 Base name (without suffix, relative to arch/loongarch/boot/dts/) 410 for the DTS file that will be used to produce the DTB linked into 411 the kernel. 412 413config DMI 414 bool "Enable DMI scanning" 415 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 416 default y 417 help 418 This enables SMBIOS/DMI feature for systems, and scanning of 419 DMI to identify machine quirks. 420 421config EFI 422 bool "EFI runtime service support" 423 select UCS2_STRING 424 select EFI_RUNTIME_WRAPPERS 425 help 426 This enables the kernel to use EFI runtime services that are 427 available (such as the EFI variable services). 428 429config EFI_STUB 430 bool "EFI boot stub support" 431 default y 432 depends on EFI 433 select EFI_GENERIC_STUB 434 help 435 This kernel feature allows the kernel to be loaded directly by 436 EFI firmware without the use of a bootloader. 437 438config SCHED_SMT 439 bool "SMT scheduler support" 440 depends on SMP 441 default y 442 help 443 Improves scheduler's performance when there are multiple 444 threads in one physical core. 445 446config SMP 447 bool "Multi-Processing support" 448 help 449 This enables support for systems with more than one CPU. If you have 450 a system with only one CPU, say N. If you have a system with more 451 than one CPU, say Y. 452 453 If you say N here, the kernel will run on uni- and multiprocessor 454 machines, but will use only one CPU of a multiprocessor machine. If 455 you say Y here, the kernel will run on many, but not all, 456 uniprocessor machines. On a uniprocessor machine, the kernel 457 will run faster if you say N here. 458 459 See also the SMP-HOWTO available at <http://www.tldp.org/docs.html#howto>. 460 461 If you don't know what to do here, say N. 462 463config HOTPLUG_CPU 464 bool "Support for hot-pluggable CPUs" 465 depends on SMP 466 select GENERIC_IRQ_MIGRATION 467 help 468 Say Y here to allow turning CPUs off and on. CPUs can be 469 controlled through /sys/devices/system/cpu. 470 (Note: power management support will enable this option 471 automatically on SMP systems. ) 472 Say N if you want to disable CPU hotplug. 473 474config NR_CPUS 475 int "Maximum number of CPUs (2-256)" 476 range 2 256 477 depends on SMP 478 default "64" 479 help 480 This allows you to specify the maximum number of CPUs which this 481 kernel will support. 482 483config NUMA 484 bool "NUMA Support" 485 select SMP 486 help 487 Say Y to compile the kernel with NUMA (Non-Uniform Memory Access) 488 support. This option improves performance on systems with more 489 than one NUMA node; on single node systems it is generally better 490 to leave it disabled. 491 492config NODES_SHIFT 493 int 494 default "6" 495 depends on NUMA 496 497config ARCH_FORCE_MAX_ORDER 498 int "Maximum zone order" 499 default "13" if PAGE_SIZE_64KB 500 default "11" if PAGE_SIZE_16KB 501 default "10" 502 help 503 The kernel memory allocator divides physically contiguous memory 504 blocks into "zones", where each zone is a power of two number of 505 pages. This option selects the largest power of two that the kernel 506 keeps in the memory allocator. If you need to allocate very large 507 blocks of physically contiguous memory, then you may need to 508 increase this value. 509 510 The page size is not necessarily 4KB. Keep this in mind 511 when choosing a value for this option. 512 513config ARCH_IOREMAP 514 bool "Enable LoongArch DMW-based ioremap()" 515 help 516 We use generic TLB-based ioremap() by default since it has page 517 protection support. However, you can enable LoongArch DMW-based 518 ioremap() for better performance. 519 520config ARCH_WRITECOMBINE 521 bool "Enable WriteCombine (WUC) for ioremap()" 522 help 523 LoongArch maintains cache coherency in hardware, but when paired 524 with LS7A chipsets the WUC attribute (Weak-ordered UnCached, which 525 is similar to WriteCombine) is out of the scope of cache coherency 526 machanism for PCIe devices (this is a PCIe protocol violation, which 527 may be fixed in newer chipsets). 528 529 This means WUC can only used for write-only memory regions now, so 530 this option is disabled by default, making WUC silently fallback to 531 SUC for ioremap(). You can enable this option if the kernel is ensured 532 to run on hardware without this bug. 533 534 You can override this setting via writecombine=on/off boot parameter. 535 536config ARCH_STRICT_ALIGN 537 bool "Enable -mstrict-align to prevent unaligned accesses" if EXPERT 538 default y 539 help 540 Not all LoongArch cores support h/w unaligned access, we can use 541 -mstrict-align build parameter to prevent unaligned accesses. 542 543 CPUs with h/w unaligned access support: 544 Loongson-2K2000/2K3000/3A5000/3C5000/3D5000. 545 546 CPUs without h/w unaligned access support: 547 Loongson-2K500/2K1000. 548 549 This option is enabled by default to make the kernel be able to run 550 on all LoongArch systems. But you can disable it manually if you want 551 to run kernel only on systems with h/w unaligned access support in 552 order to optimise for performance. 553 554config CPU_HAS_FPU 555 bool 556 default y 557 558config CPU_HAS_LSX 559 bool "Support for the Loongson SIMD Extension" 560 depends on AS_HAS_LSX_EXTENSION 561 help 562 Loongson SIMD Extension (LSX) introduces 128 bit wide vector registers 563 and a set of SIMD instructions to operate on them. When this option 564 is enabled the kernel will support allocating & switching LSX 565 vector register contexts. If you know that your kernel will only be 566 running on CPUs which do not support LSX or that your userland will 567 not be making use of it then you may wish to say N here to reduce 568 the size & complexity of your kernel. 569 570 If unsure, say Y. 571 572config CPU_HAS_LASX 573 bool "Support for the Loongson Advanced SIMD Extension" 574 depends on CPU_HAS_LSX 575 depends on AS_HAS_LASX_EXTENSION 576 help 577 Loongson Advanced SIMD Extension (LASX) introduces 256 bit wide vector 578 registers and a set of SIMD instructions to operate on them. When this 579 option is enabled the kernel will support allocating & switching LASX 580 vector register contexts. If you know that your kernel will only be 581 running on CPUs which do not support LASX or that your userland will 582 not be making use of it then you may wish to say N here to reduce 583 the size & complexity of your kernel. 584 585 If unsure, say Y. 586 587config CPU_HAS_LBT 588 bool "Support for the Loongson Binary Translation Extension" 589 depends on AS_HAS_LBT_EXTENSION 590 help 591 Loongson Binary Translation (LBT) introduces 4 scratch registers (SCR0 592 to SCR3), x86/ARM eflags (eflags) and x87 fpu stack pointer (ftop). 593 Enabling this option allows the kernel to allocate and switch registers 594 specific to LBT. 595 596 If you want to use this feature, such as the Loongson Architecture 597 Translator (LAT), say Y. 598 599config CPU_HAS_PREFETCH 600 bool 601 default y 602 603config ARCH_SUPPORTS_KEXEC 604 def_bool y 605 606config ARCH_SUPPORTS_CRASH_DUMP 607 def_bool y 608 609config ARCH_DEFAULT_CRASH_DUMP 610 def_bool y 611 612config ARCH_SELECTS_CRASH_DUMP 613 def_bool y 614 depends on CRASH_DUMP 615 select RELOCATABLE 616 617config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 618 def_bool CRASH_RESERVE 619 620config RELOCATABLE 621 bool "Relocatable kernel" 622 select ARCH_HAS_RELR 623 help 624 This builds the kernel as a Position Independent Executable (PIE), 625 which retains all relocation metadata required, so as to relocate 626 the kernel binary at runtime to a different virtual address from 627 its link address. 628 629config RANDOMIZE_BASE 630 bool "Randomize the address of the kernel (KASLR)" 631 depends on RELOCATABLE 632 help 633 Randomizes the physical and virtual address at which the 634 kernel image is loaded, as a security feature that 635 deters exploit attempts relying on knowledge of the location 636 of kernel internals. 637 638 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET. 639 640 If unsure, say N. 641 642config RANDOMIZE_BASE_MAX_OFFSET 643 hex "Maximum KASLR offset" if EXPERT 644 depends on RANDOMIZE_BASE 645 range 0x0 0x10000000 646 default "0x01000000" 647 help 648 When KASLR is active, this provides the maximum offset that will 649 be applied to the kernel image. It should be set according to the 650 amount of physical RAM available in the target system. 651 652 This is limited by the size of the lower address memory, 256MB. 653 654source "kernel/livepatch/Kconfig" 655 656config PARAVIRT 657 bool "Enable paravirtualization code" 658 depends on AS_HAS_LVZ_EXTENSION 659 help 660 This changes the kernel so it can modify itself when it is run 661 under a hypervisor, potentially improving performance significantly 662 over full virtualization. However, when run without a hypervisor 663 the kernel is theoretically slower and slightly larger. 664 665config PARAVIRT_TIME_ACCOUNTING 666 bool "Paravirtual steal time accounting" 667 depends on PARAVIRT 668 help 669 Select this option to enable fine granularity task steal time 670 accounting. Time spent executing other tasks in parallel with 671 the current vCPU is discounted from the vCPU power. To account for 672 that, there can be a small performance impact. 673 674 If in doubt, say N here. 675 676endmenu 677 678config ARCH_SELECT_MEMORY_MODEL 679 def_bool y 680 681config ARCH_FLATMEM_ENABLE 682 def_bool y 683 depends on !NUMA 684 685config ARCH_SPARSEMEM_ENABLE 686 def_bool y 687 select SPARSEMEM_VMEMMAP_ENABLE 688 help 689 Say Y to support efficient handling of sparse physical memory, 690 for architectures which are either NUMA (Non-Uniform Memory Access) 691 or have huge holes in the physical address space for other reasons. 692 See <file:Documentation/mm/numa.rst> for more. 693 694config ARCH_MEMORY_PROBE 695 def_bool y 696 depends on MEMORY_HOTPLUG 697 698config MMU 699 bool 700 default y 701 702config ARCH_MMAP_RND_BITS_MIN 703 default 12 704 705config ARCH_MMAP_RND_BITS_MAX 706 default 18 707 708config ARCH_SUPPORTS_UPROBES 709 def_bool y 710 711config KASAN_SHADOW_OFFSET 712 hex 713 default 0x0 714 depends on KASAN 715 716menu "Power management options" 717 718config ARCH_SUSPEND_POSSIBLE 719 def_bool y 720 721config ARCH_HIBERNATION_POSSIBLE 722 def_bool y 723 724source "kernel/power/Kconfig" 725source "drivers/acpi/Kconfig" 726source "drivers/cpufreq/Kconfig" 727 728endmenu 729 730source "arch/loongarch/kvm/Kconfig" 731