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