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