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_PREEMPT_LAZY 27 select ARCH_HAS_PTE_DEVMAP 28 select ARCH_HAS_PTE_SPECIAL 29 select ARCH_HAS_SET_MEMORY 30 select ARCH_HAS_SET_DIRECT_MAP 31 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST 32 select ARCH_INLINE_READ_LOCK if !PREEMPTION 33 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION 34 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION 35 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION 36 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION 37 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION 38 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION 39 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION 40 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION 41 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION 42 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION 43 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION 44 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION 45 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION 46 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION 47 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION 48 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION 49 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION 50 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION 51 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION 52 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION 53 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION 54 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION 55 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION 56 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION 57 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION 58 select ARCH_KEEP_MEMBLOCK 59 select ARCH_MIGHT_HAVE_PC_PARPORT 60 select ARCH_MIGHT_HAVE_PC_SERIO 61 select ARCH_SPARSEMEM_ENABLE 62 select ARCH_STACKWALK 63 select ARCH_SUPPORTS_ACPI 64 select ARCH_SUPPORTS_ATOMIC_RMW 65 select ARCH_SUPPORTS_HUGETLBFS 66 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 67 select ARCH_SUPPORTS_LTO_CLANG 68 select ARCH_SUPPORTS_LTO_CLANG_THIN 69 select ARCH_SUPPORTS_NUMA_BALANCING 70 select ARCH_SUPPORTS_RT 71 select ARCH_USE_BUILTIN_BSWAP 72 select ARCH_USE_CMPXCHG_LOCKREF 73 select ARCH_USE_QUEUED_RWLOCKS 74 select ARCH_USE_QUEUED_SPINLOCKS 75 select ARCH_WANT_DEFAULT_BPF_JIT 76 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 77 select ARCH_WANT_LD_ORPHAN_WARN 78 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP 79 select ARCH_WANTS_NO_INSTR 80 select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE 81 select BUILDTIME_TABLE_SORT 82 select COMMON_CLK 83 select CPU_PM 84 select EFI 85 select GENERIC_CLOCKEVENTS 86 select GENERIC_CMOS_UPDATE 87 select GENERIC_CPU_AUTOPROBE 88 select GENERIC_CPU_DEVICES 89 select GENERIC_CPU_VULNERABILITIES 90 select GENERIC_ENTRY 91 select GENERIC_GETTIMEOFDAY 92 select GENERIC_IOREMAP if !ARCH_IOREMAP 93 select GENERIC_IRQ_MATRIX_ALLOCATOR 94 select GENERIC_IRQ_MULTI_HANDLER 95 select GENERIC_IRQ_PROBE 96 select GENERIC_IRQ_SHOW 97 select GENERIC_LIB_ASHLDI3 98 select GENERIC_LIB_ASHRDI3 99 select GENERIC_LIB_CMPDI2 100 select GENERIC_LIB_LSHRDI3 101 select GENERIC_LIB_UCMPDI2 102 select GENERIC_LIB_DEVMEM_IS_ALLOWED 103 select GENERIC_PCI_IOMAP 104 select GENERIC_SCHED_CLOCK 105 select GENERIC_SMP_IDLE_THREAD 106 select GENERIC_TIME_VSYSCALL 107 select GENERIC_VDSO_TIME_NS 108 select GPIOLIB 109 select HAS_IOPORT 110 select HAVE_ARCH_AUDITSYSCALL 111 select HAVE_ARCH_JUMP_LABEL 112 select HAVE_ARCH_JUMP_LABEL_RELATIVE 113 select HAVE_ARCH_KASAN 114 select HAVE_ARCH_KFENCE 115 select HAVE_ARCH_KGDB if PERF_EVENTS 116 select HAVE_ARCH_MMAP_RND_BITS if MMU 117 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 118 select HAVE_ARCH_SECCOMP 119 select HAVE_ARCH_SECCOMP_FILTER 120 select HAVE_ARCH_TRACEHOOK 121 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 122 select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD 123 select HAVE_ASM_MODVERSIONS 124 select HAVE_CONTEXT_TRACKING_USER 125 select HAVE_C_RECORDMCOUNT 126 select HAVE_DEBUG_KMEMLEAK 127 select HAVE_DEBUG_STACKOVERFLOW 128 select HAVE_DMA_CONTIGUOUS 129 select HAVE_DYNAMIC_FTRACE 130 select HAVE_DYNAMIC_FTRACE_WITH_ARGS 131 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 132 select HAVE_DYNAMIC_FTRACE_WITH_REGS 133 select HAVE_EBPF_JIT 134 select HAVE_EFFICIENT_UNALIGNED_ACCESS if !ARCH_STRICT_ALIGN 135 select HAVE_EXIT_THREAD 136 select HAVE_GUP_FAST 137 select HAVE_FTRACE_MCOUNT_RECORD 138 select HAVE_FUNCTION_ARG_ACCESS_API 139 select HAVE_FUNCTION_ERROR_INJECTION 140 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 141 select HAVE_FUNCTION_GRAPH_TRACER 142 select HAVE_FUNCTION_TRACER 143 select HAVE_GCC_PLUGINS 144 select HAVE_GENERIC_VDSO 145 select HAVE_HW_BREAKPOINT if PERF_EVENTS 146 select HAVE_IOREMAP_PROT 147 select HAVE_IRQ_EXIT_ON_IRQ_STACK 148 select HAVE_IRQ_TIME_ACCOUNTING 149 select HAVE_KPROBES 150 select HAVE_KPROBES_ON_FTRACE 151 select HAVE_KRETPROBES 152 select HAVE_LIVEPATCH 153 select HAVE_MOD_ARCH_SPECIFIC 154 select HAVE_NMI 155 select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS && AS_HAS_THIN_ADD_SUB 156 select HAVE_PCI 157 select HAVE_PERF_EVENTS 158 select HAVE_PERF_REGS 159 select HAVE_PERF_USER_STACK_DUMP 160 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 161 select HAVE_PREEMPT_DYNAMIC_KEY 162 select HAVE_REGS_AND_STACK_ACCESS_API 163 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC 164 select HAVE_RETHOOK 165 select HAVE_RSEQ 166 select HAVE_RUST 167 select HAVE_SAMPLE_FTRACE_DIRECT 168 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 169 select HAVE_SETUP_PER_CPU_AREA if NUMA 170 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 171 select HAVE_STACKPROTECTOR 172 select HAVE_SYSCALL_TRACEPOINTS 173 select HAVE_TIF_NOHZ 174 select HAVE_VIRT_CPU_ACCOUNTING_GEN if !SMP 175 select IRQ_FORCED_THREADING 176 select IRQ_LOONGARCH_CPU 177 select LOCK_MM_AND_FIND_VMA 178 select MMU_GATHER_MERGE_VMAS if MMU 179 select MODULES_USE_ELF_RELA if MODULES 180 select NEED_PER_CPU_EMBED_FIRST_CHUNK 181 select NEED_PER_CPU_PAGE_FIRST_CHUNK 182 select OF 183 select OF_EARLY_FLATTREE 184 select PCI 185 select PCI_DOMAINS_GENERIC 186 select PCI_ECAM if ACPI 187 select PCI_LOONGSON 188 select PCI_MSI_ARCH_FALLBACKS 189 select PCI_QUIRKS 190 select PERF_USE_VMALLOC 191 select RTC_LIB 192 select SPARSE_IRQ 193 select SYSCTL_ARCH_UNALIGN_ALLOW 194 select SYSCTL_ARCH_UNALIGN_NO_WARN 195 select SYSCTL_EXCEPTION_TRACE 196 select SWIOTLB 197 select TRACE_IRQFLAGS_SUPPORT 198 select USE_PERCPU_NUMA_NODE_ID 199 select USER_STACKTRACE_SUPPORT 200 select VDSO_GETRANDOM 201 select ZONE_DMA32 202 203config 32BIT 204 bool 205 206config 64BIT 207 def_bool y 208 209config GENERIC_BUG 210 def_bool y 211 depends on BUG 212 213config GENERIC_BUG_RELATIVE_POINTERS 214 def_bool y 215 depends on GENERIC_BUG 216 217config GENERIC_CALIBRATE_DELAY 218 def_bool y 219 220config GENERIC_CSUM 221 def_bool y 222 223config GENERIC_HWEIGHT 224 def_bool y 225 226config L1_CACHE_SHIFT 227 int 228 default "6" 229 230config LOCKDEP_SUPPORT 231 bool 232 default y 233 234config STACKTRACE_SUPPORT 235 bool 236 default y 237 238# MACH_LOONGSON32 and MACH_LOONGSON64 are deliberately carried over from the 239# MIPS Loongson code, to preserve Loongson-specific code paths in drivers that 240# are shared between architectures, and specifically expecting the symbols. 241config MACH_LOONGSON32 242 def_bool 32BIT 243 244config MACH_LOONGSON64 245 def_bool 64BIT 246 247config FIX_EARLYCON_MEM 248 def_bool y 249 250config PGTABLE_2LEVEL 251 bool 252 253config PGTABLE_3LEVEL 254 bool 255 256config PGTABLE_4LEVEL 257 bool 258 259config PGTABLE_LEVELS 260 int 261 default 2 if PGTABLE_2LEVEL 262 default 3 if PGTABLE_3LEVEL 263 default 4 if PGTABLE_4LEVEL 264 265config SCHED_OMIT_FRAME_POINTER 266 bool 267 default y 268 269config AS_HAS_EXPLICIT_RELOCS 270 def_bool $(as-instr,x:pcalau12i \$t0$(comma)%pc_hi20(x)) 271 272config AS_HAS_FCSR_CLASS 273 def_bool $(as-instr,movfcsr2gr \$t0$(comma)\$fcsr0) 274 275config AS_HAS_THIN_ADD_SUB 276 def_bool $(cc-option,-Wa$(comma)-mthin-add-sub) || AS_IS_LLVM 277 278config AS_HAS_LSX_EXTENSION 279 def_bool $(as-instr,vld \$vr0$(comma)\$a0$(comma)0) 280 281config AS_HAS_LASX_EXTENSION 282 def_bool $(as-instr,xvld \$xr0$(comma)\$a0$(comma)0) 283 284config AS_HAS_LBT_EXTENSION 285 def_bool $(as-instr,movscr2gr \$a0$(comma)\$scr0) 286 287config AS_HAS_LVZ_EXTENSION 288 def_bool $(as-instr,hvcl 0) 289 290menu "Kernel type and options" 291 292source "kernel/Kconfig.hz" 293 294choice 295 prompt "Page Table Layout" 296 default 16KB_2LEVEL if 32BIT 297 default 16KB_3LEVEL if 64BIT 298 help 299 Allows choosing the page table layout, which is a combination 300 of page size and page table levels. The size of virtual memory 301 address space are determined by the page table layout. 302 303config 4KB_3LEVEL 304 bool "4KB with 3 levels" 305 select HAVE_PAGE_SIZE_4KB 306 select PGTABLE_3LEVEL 307 help 308 This option selects 4KB page size with 3 level page tables, which 309 support a maximum of 39 bits of application virtual memory. 310 311config 4KB_4LEVEL 312 bool "4KB with 4 levels" 313 select HAVE_PAGE_SIZE_4KB 314 select PGTABLE_4LEVEL 315 help 316 This option selects 4KB page size with 4 level page tables, which 317 support a maximum of 48 bits of application virtual memory. 318 319config 16KB_2LEVEL 320 bool "16KB with 2 levels" 321 select HAVE_PAGE_SIZE_16KB 322 select PGTABLE_2LEVEL 323 help 324 This option selects 16KB page size with 2 level page tables, which 325 support a maximum of 36 bits of application virtual memory. 326 327config 16KB_3LEVEL 328 bool "16KB with 3 levels" 329 select HAVE_PAGE_SIZE_16KB 330 select PGTABLE_3LEVEL 331 help 332 This option selects 16KB page size with 3 level page tables, which 333 support a maximum of 47 bits of application virtual memory. 334 335config 64KB_2LEVEL 336 bool "64KB with 2 levels" 337 select HAVE_PAGE_SIZE_64KB 338 select PGTABLE_2LEVEL 339 help 340 This option selects 64KB page size with 2 level page tables, which 341 support a maximum of 42 bits of application virtual memory. 342 343config 64KB_3LEVEL 344 bool "64KB with 3 levels" 345 select HAVE_PAGE_SIZE_64KB 346 select PGTABLE_3LEVEL 347 help 348 This option selects 64KB page size with 3 level page tables, which 349 support a maximum of 55 bits of application virtual memory. 350 351endchoice 352 353config CMDLINE 354 string "Built-in kernel command line" 355 help 356 For most platforms, the arguments for the kernel's command line 357 are provided at run-time, during boot. However, there are cases 358 where either no arguments are being provided or the provided 359 arguments are insufficient or even invalid. 360 361 When that occurs, it is possible to define a built-in command 362 line here and choose how the kernel should use it later on. 363 364choice 365 prompt "Kernel command line type" 366 default CMDLINE_BOOTLOADER 367 help 368 Choose how the kernel will handle the provided built-in command 369 line. 370 371config CMDLINE_BOOTLOADER 372 bool "Use bootloader kernel arguments if available" 373 help 374 Prefer the command-line passed by the boot loader if available. 375 Use the built-in command line as fallback in case we get nothing 376 during boot. This is the default behaviour. 377 378config CMDLINE_EXTEND 379 bool "Use built-in to extend bootloader kernel arguments" 380 help 381 The command-line arguments provided during boot will be 382 appended to the built-in command line. This is useful in 383 cases where the provided arguments are insufficient and 384 you don't want to or cannot modify them. 385 386config CMDLINE_FORCE 387 bool "Always use the built-in kernel command string" 388 help 389 Always use the built-in command line, even if we get one during 390 boot. This is useful in case you need to override the provided 391 command line on systems where you don't have or want control 392 over it. 393 394endchoice 395 396config BUILTIN_DTB 397 bool "Enable built-in dtb in kernel" 398 depends on OF 399 help 400 Some existing systems do not provide a canonical device tree to 401 the kernel at boot time. Let's provide a device tree table in the 402 kernel, keyed by the dts filename, containing the relevant DTBs. 403 404 Built-in DTBs are generic enough and can be used as references. 405 406config BUILTIN_DTB_NAME 407 string "Source file for built-in dtb" 408 depends on BUILTIN_DTB 409 help 410 Base name (without suffix, relative to arch/loongarch/boot/dts/) 411 for the DTS file that will be used to produce the DTB linked into 412 the kernel. 413 414config DMI 415 bool "Enable DMI scanning" 416 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 417 default y 418 help 419 This enables SMBIOS/DMI feature for systems, and scanning of 420 DMI to identify machine quirks. 421 422config EFI 423 bool "EFI runtime service support" 424 select UCS2_STRING 425 select EFI_RUNTIME_WRAPPERS 426 help 427 This enables the kernel to use EFI runtime services that are 428 available (such as the EFI variable services). 429 430config EFI_STUB 431 bool "EFI boot stub support" 432 default y 433 depends on EFI 434 select EFI_GENERIC_STUB 435 help 436 This kernel feature allows the kernel to be loaded directly by 437 EFI firmware without the use of a bootloader. 438 439config SCHED_SMT 440 bool "SMT scheduler support" 441 depends on SMP 442 default y 443 help 444 Improves scheduler's performance when there are multiple 445 threads in one physical core. 446 447config SMP 448 bool "Multi-Processing support" 449 help 450 This enables support for systems with more than one CPU. If you have 451 a system with only one CPU, say N. If you have a system with more 452 than one CPU, say Y. 453 454 If you say N here, the kernel will run on uni- and multiprocessor 455 machines, but will use only one CPU of a multiprocessor machine. If 456 you say Y here, the kernel will run on many, but not all, 457 uniprocessor machines. On a uniprocessor machine, the kernel 458 will run faster if you say N here. 459 460 See also the SMP-HOWTO available at <http://www.tldp.org/docs.html#howto>. 461 462 If you don't know what to do here, say N. 463 464config HOTPLUG_CPU 465 bool "Support for hot-pluggable CPUs" 466 depends on SMP 467 select GENERIC_IRQ_MIGRATION 468 help 469 Say Y here to allow turning CPUs off and on. CPUs can be 470 controlled through /sys/devices/system/cpu. 471 (Note: power management support will enable this option 472 automatically on SMP systems. ) 473 Say N if you want to disable CPU hotplug. 474 475config NR_CPUS 476 int "Maximum number of CPUs (2-256)" 477 range 2 256 478 depends on SMP 479 default "64" 480 help 481 This allows you to specify the maximum number of CPUs which this 482 kernel will support. 483 484config NUMA 485 bool "NUMA Support" 486 select SMP 487 help 488 Say Y to compile the kernel with NUMA (Non-Uniform Memory Access) 489 support. This option improves performance on systems with more 490 than one NUMA node; on single node systems it is generally better 491 to leave it disabled. 492 493config NODES_SHIFT 494 int 495 default "6" 496 depends on NUMA 497 498config ARCH_FORCE_MAX_ORDER 499 int "Maximum zone order" 500 default "13" if PAGE_SIZE_64KB 501 default "11" if PAGE_SIZE_16KB 502 default "10" 503 help 504 The kernel memory allocator divides physically contiguous memory 505 blocks into "zones", where each zone is a power of two number of 506 pages. This option selects the largest power of two that the kernel 507 keeps in the memory allocator. If you need to allocate very large 508 blocks of physically contiguous memory, then you may need to 509 increase this value. 510 511 The page size is not necessarily 4KB. Keep this in mind 512 when choosing a value for this option. 513 514config ARCH_IOREMAP 515 bool "Enable LoongArch DMW-based ioremap()" 516 help 517 We use generic TLB-based ioremap() by default since it has page 518 protection support. However, you can enable LoongArch DMW-based 519 ioremap() for better performance. 520 521config ARCH_WRITECOMBINE 522 bool "Enable WriteCombine (WUC) for ioremap()" 523 help 524 LoongArch maintains cache coherency in hardware, but when paired 525 with LS7A chipsets the WUC attribute (Weak-ordered UnCached, which 526 is similar to WriteCombine) is out of the scope of cache coherency 527 machanism for PCIe devices (this is a PCIe protocol violation, which 528 may be fixed in newer chipsets). 529 530 This means WUC can only used for write-only memory regions now, so 531 this option is disabled by default, making WUC silently fallback to 532 SUC for ioremap(). You can enable this option if the kernel is ensured 533 to run on hardware without this bug. 534 535 You can override this setting via writecombine=on/off boot parameter. 536 537config ARCH_STRICT_ALIGN 538 bool "Enable -mstrict-align to prevent unaligned accesses" if EXPERT 539 default y 540 help 541 Not all LoongArch cores support h/w unaligned access, we can use 542 -mstrict-align build parameter to prevent unaligned accesses. 543 544 CPUs with h/w unaligned access support: 545 Loongson-2K2000/2K3000/3A5000/3C5000/3D5000. 546 547 CPUs without h/w unaligned access support: 548 Loongson-2K500/2K1000. 549 550 This option is enabled by default to make the kernel be able to run 551 on all LoongArch systems. But you can disable it manually if you want 552 to run kernel only on systems with h/w unaligned access support in 553 order to optimise for performance. 554 555config CPU_HAS_FPU 556 bool 557 default y 558 559config CPU_HAS_LSX 560 bool "Support for the Loongson SIMD Extension" 561 depends on AS_HAS_LSX_EXTENSION 562 help 563 Loongson SIMD Extension (LSX) introduces 128 bit wide vector registers 564 and a set of SIMD instructions to operate on them. When this option 565 is enabled the kernel will support allocating & switching LSX 566 vector register contexts. If you know that your kernel will only be 567 running on CPUs which do not support LSX or that your userland will 568 not be making use of it then you may wish to say N here to reduce 569 the size & complexity of your kernel. 570 571 If unsure, say Y. 572 573config CPU_HAS_LASX 574 bool "Support for the Loongson Advanced SIMD Extension" 575 depends on CPU_HAS_LSX 576 depends on AS_HAS_LASX_EXTENSION 577 help 578 Loongson Advanced SIMD Extension (LASX) introduces 256 bit wide vector 579 registers and a set of SIMD instructions to operate on them. When this 580 option is enabled the kernel will support allocating & switching LASX 581 vector register contexts. If you know that your kernel will only be 582 running on CPUs which do not support LASX or that your userland will 583 not be making use of it then you may wish to say N here to reduce 584 the size & complexity of your kernel. 585 586 If unsure, say Y. 587 588config CPU_HAS_LBT 589 bool "Support for the Loongson Binary Translation Extension" 590 depends on AS_HAS_LBT_EXTENSION 591 help 592 Loongson Binary Translation (LBT) introduces 4 scratch registers (SCR0 593 to SCR3), x86/ARM eflags (eflags) and x87 fpu stack pointer (ftop). 594 Enabling this option allows the kernel to allocate and switch registers 595 specific to LBT. 596 597 If you want to use this feature, such as the Loongson Architecture 598 Translator (LAT), say Y. 599 600config CPU_HAS_PREFETCH 601 bool 602 default y 603 604config ARCH_SUPPORTS_KEXEC 605 def_bool y 606 607config ARCH_SUPPORTS_CRASH_DUMP 608 def_bool y 609 610config ARCH_DEFAULT_CRASH_DUMP 611 def_bool y 612 613config ARCH_SELECTS_CRASH_DUMP 614 def_bool y 615 depends on CRASH_DUMP 616 select RELOCATABLE 617 618config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 619 def_bool CRASH_RESERVE 620 621config RELOCATABLE 622 bool "Relocatable kernel" 623 select ARCH_HAS_RELR 624 help 625 This builds the kernel as a Position Independent Executable (PIE), 626 which retains all relocation metadata required, so as to relocate 627 the kernel binary at runtime to a different virtual address from 628 its link address. 629 630config RANDOMIZE_BASE 631 bool "Randomize the address of the kernel (KASLR)" 632 depends on RELOCATABLE 633 help 634 Randomizes the physical and virtual address at which the 635 kernel image is loaded, as a security feature that 636 deters exploit attempts relying on knowledge of the location 637 of kernel internals. 638 639 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET. 640 641 If unsure, say N. 642 643config RANDOMIZE_BASE_MAX_OFFSET 644 hex "Maximum KASLR offset" if EXPERT 645 depends on RANDOMIZE_BASE 646 range 0x0 0x10000000 647 default "0x01000000" 648 help 649 When KASLR is active, this provides the maximum offset that will 650 be applied to the kernel image. It should be set according to the 651 amount of physical RAM available in the target system. 652 653 This is limited by the size of the lower address memory, 256MB. 654 655source "kernel/livepatch/Kconfig" 656 657config PARAVIRT 658 bool "Enable paravirtualization code" 659 depends on AS_HAS_LVZ_EXTENSION 660 help 661 This changes the kernel so it can modify itself when it is run 662 under a hypervisor, potentially improving performance significantly 663 over full virtualization. However, when run without a hypervisor 664 the kernel is theoretically slower and slightly larger. 665 666config PARAVIRT_TIME_ACCOUNTING 667 bool "Paravirtual steal time accounting" 668 depends on PARAVIRT 669 help 670 Select this option to enable fine granularity task steal time 671 accounting. Time spent executing other tasks in parallel with 672 the current vCPU is discounted from the vCPU power. To account for 673 that, there can be a small performance impact. 674 675 If in doubt, say N here. 676 677endmenu 678 679config ARCH_SELECT_MEMORY_MODEL 680 def_bool y 681 682config ARCH_FLATMEM_ENABLE 683 def_bool y 684 depends on !NUMA 685 686config ARCH_SPARSEMEM_ENABLE 687 def_bool y 688 select SPARSEMEM_VMEMMAP_ENABLE 689 help 690 Say Y to support efficient handling of sparse physical memory, 691 for architectures which are either NUMA (Non-Uniform Memory Access) 692 or have huge holes in the physical address space for other reasons. 693 See <file:Documentation/mm/numa.rst> for more. 694 695config ARCH_MEMORY_PROBE 696 def_bool y 697 depends on MEMORY_HOTPLUG 698 699config MMU 700 bool 701 default y 702 703config ARCH_MMAP_RND_BITS_MIN 704 default 12 705 706config ARCH_MMAP_RND_BITS_MAX 707 default 18 708 709config ARCH_SUPPORTS_UPROBES 710 def_bool y 711 712config KASAN_SHADOW_OFFSET 713 hex 714 default 0x0 715 depends on KASAN 716 717menu "Power management options" 718 719config ARCH_SUSPEND_POSSIBLE 720 def_bool y 721 722config ARCH_HIBERNATION_POSSIBLE 723 def_bool y 724 725source "kernel/power/Kconfig" 726source "drivers/acpi/Kconfig" 727source "drivers/cpufreq/Kconfig" 728 729endmenu 730 731source "arch/loongarch/kvm/Kconfig" 732