1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 select ARCH_SPLIT_ARG64 22 23config X86_64 24 def_bool y 25 depends on 64BIT 26 # Options that are inherently 64-bit kernel only: 27 select ARCH_HAS_GIGANTIC_PAGE 28 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 29 select ARCH_USE_CMPXCHG_LOCKREF 30 select HAVE_ARCH_SOFT_DIRTY 31 select MODULES_USE_ELF_RELA 32 select NEED_DMA_MAP_STATE 33 select SWIOTLB 34 35config FORCE_DYNAMIC_FTRACE 36 def_bool y 37 depends on X86_32 38 depends on FUNCTION_TRACER 39 select DYNAMIC_FTRACE 40 help 41 We keep the static function tracing (!DYNAMIC_FTRACE) around 42 in order to test the non static function tracing in the 43 generic code, as other architectures still use it. But we 44 only need to keep it around for x86_64. No need to keep it 45 for x86_32. For x86_32, force DYNAMIC_FTRACE. 46# 47# Arch settings 48# 49# ( Note that options that are marked 'if X86_64' could in principle be 50# ported to 32-bit as well. ) 51# 52config X86 53 def_bool y 54 # 55 # Note: keep this list sorted alphabetically 56 # 57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 59 select ARCH_32BIT_OFF_T if X86_32 60 select ARCH_CLOCKSOURCE_INIT 61 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 62 select ARCH_HAS_DEBUG_VIRTUAL 63 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 64 select ARCH_HAS_DEVMEM_IS_ALLOWED 65 select ARCH_HAS_EARLY_DEBUG if KGDB 66 select ARCH_HAS_ELF_RANDOMIZE 67 select ARCH_HAS_FAST_MULTIPLIER 68 select ARCH_HAS_FILTER_PGPROT 69 select ARCH_HAS_FORTIFY_SOURCE 70 select ARCH_HAS_GCOV_PROFILE_ALL 71 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 72 select ARCH_HAS_MEM_ENCRYPT 73 select ARCH_HAS_MEMBARRIER_SYNC_CORE 74 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 75 select ARCH_HAS_PMEM_API if X86_64 76 select ARCH_HAS_PTE_DEVMAP if X86_64 77 select ARCH_HAS_PTE_SPECIAL 78 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 79 select ARCH_HAS_COPY_MC if X86_64 80 select ARCH_HAS_SET_MEMORY 81 select ARCH_HAS_SET_DIRECT_MAP 82 select ARCH_HAS_STRICT_KERNEL_RWX 83 select ARCH_HAS_STRICT_MODULE_RWX 84 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 85 select ARCH_HAS_SYSCALL_WRAPPER 86 select ARCH_HAS_UBSAN_SANITIZE_ALL 87 select ARCH_HAS_DEBUG_WX 88 select ARCH_HAVE_NMI_SAFE_CMPXCHG 89 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 90 select ARCH_MIGHT_HAVE_PC_PARPORT 91 select ARCH_MIGHT_HAVE_PC_SERIO 92 select ARCH_STACKWALK 93 select ARCH_SUPPORTS_ACPI 94 select ARCH_SUPPORTS_ATOMIC_RMW 95 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 96 select ARCH_USE_BUILTIN_BSWAP 97 select ARCH_USE_QUEUED_RWLOCKS 98 select ARCH_USE_QUEUED_SPINLOCKS 99 select ARCH_USE_SYM_ANNOTATIONS 100 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 101 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 102 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 103 select ARCH_WANT_HUGE_PMD_SHARE 104 select ARCH_WANT_LD_ORPHAN_WARN 105 select ARCH_WANTS_THP_SWAP if X86_64 106 select BUILDTIME_TABLE_SORT 107 select CLKEVT_I8253 108 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 109 select CLOCKSOURCE_WATCHDOG 110 select DCACHE_WORD_ACCESS 111 select EDAC_ATOMIC_SCRUB 112 select EDAC_SUPPORT 113 select GENERIC_CLOCKEVENTS 114 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 115 select GENERIC_CLOCKEVENTS_MIN_ADJUST 116 select GENERIC_CMOS_UPDATE 117 select GENERIC_CPU_AUTOPROBE 118 select GENERIC_CPU_VULNERABILITIES 119 select GENERIC_EARLY_IOREMAP 120 select GENERIC_ENTRY 121 select GENERIC_FIND_FIRST_BIT 122 select GENERIC_IOMAP 123 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 124 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 125 select GENERIC_IRQ_MIGRATION if SMP 126 select GENERIC_IRQ_PROBE 127 select GENERIC_IRQ_RESERVATION_MODE 128 select GENERIC_IRQ_SHOW 129 select GENERIC_PENDING_IRQ if SMP 130 select GENERIC_PTDUMP 131 select GENERIC_SMP_IDLE_THREAD 132 select GENERIC_STRNCPY_FROM_USER 133 select GENERIC_STRNLEN_USER 134 select GENERIC_TIME_VSYSCALL 135 select GENERIC_GETTIMEOFDAY 136 select GENERIC_VDSO_TIME_NS 137 select GUP_GET_PTE_LOW_HIGH if X86_PAE 138 select HARDIRQS_SW_RESEND 139 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 140 select HAVE_ACPI_APEI if ACPI 141 select HAVE_ACPI_APEI_NMI if ACPI 142 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 143 select HAVE_ARCH_AUDITSYSCALL 144 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 145 select HAVE_ARCH_JUMP_LABEL 146 select HAVE_ARCH_JUMP_LABEL_RELATIVE 147 select HAVE_ARCH_KASAN if X86_64 148 select HAVE_ARCH_KASAN_VMALLOC if X86_64 149 select HAVE_ARCH_KGDB 150 select HAVE_ARCH_MMAP_RND_BITS if MMU 151 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 152 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 153 select HAVE_ARCH_PREL32_RELOCATIONS 154 select HAVE_ARCH_SECCOMP_FILTER 155 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 156 select HAVE_ARCH_STACKLEAK 157 select HAVE_ARCH_TRACEHOOK 158 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 159 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 160 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 161 select HAVE_ARCH_VMAP_STACK if X86_64 162 select HAVE_ARCH_WITHIN_STACK_FRAMES 163 select HAVE_ASM_MODVERSIONS 164 select HAVE_CMPXCHG_DOUBLE 165 select HAVE_CMPXCHG_LOCAL 166 select HAVE_CONTEXT_TRACKING if X86_64 167 select HAVE_C_RECORDMCOUNT 168 select HAVE_DEBUG_KMEMLEAK 169 select HAVE_DMA_CONTIGUOUS 170 select HAVE_DYNAMIC_FTRACE 171 select HAVE_DYNAMIC_FTRACE_WITH_REGS 172 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 173 select HAVE_EBPF_JIT 174 select HAVE_EFFICIENT_UNALIGNED_ACCESS 175 select HAVE_EISA 176 select HAVE_EXIT_THREAD 177 select HAVE_FAST_GUP 178 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 179 select HAVE_FTRACE_MCOUNT_RECORD 180 select HAVE_FUNCTION_GRAPH_TRACER 181 select HAVE_FUNCTION_TRACER 182 select HAVE_GCC_PLUGINS 183 select HAVE_HW_BREAKPOINT 184 select HAVE_IDE 185 select HAVE_IOREMAP_PROT 186 select HAVE_IRQ_TIME_ACCOUNTING 187 select HAVE_KERNEL_BZIP2 188 select HAVE_KERNEL_GZIP 189 select HAVE_KERNEL_LZ4 190 select HAVE_KERNEL_LZMA 191 select HAVE_KERNEL_LZO 192 select HAVE_KERNEL_XZ 193 select HAVE_KERNEL_ZSTD 194 select HAVE_KPROBES 195 select HAVE_KPROBES_ON_FTRACE 196 select HAVE_FUNCTION_ERROR_INJECTION 197 select HAVE_KRETPROBES 198 select HAVE_KVM 199 select HAVE_LIVEPATCH if X86_64 200 select HAVE_MIXED_BREAKPOINTS_REGS 201 select HAVE_MOD_ARCH_SPECIFIC 202 select HAVE_MOVE_PMD 203 select HAVE_NMI 204 select HAVE_OPROFILE 205 select HAVE_OPTPROBES 206 select HAVE_PCSPKR_PLATFORM 207 select HAVE_PERF_EVENTS 208 select HAVE_PERF_EVENTS_NMI 209 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 210 select HAVE_PCI 211 select HAVE_PERF_REGS 212 select HAVE_PERF_USER_STACK_DUMP 213 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 214 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 215 select HAVE_REGS_AND_STACK_ACCESS_API 216 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 217 select HAVE_FUNCTION_ARG_ACCESS_API 218 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 219 select HAVE_STACK_VALIDATION if X86_64 220 select HAVE_STATIC_CALL 221 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 222 select HAVE_RSEQ 223 select HAVE_SYSCALL_TRACEPOINTS 224 select HAVE_UNSTABLE_SCHED_CLOCK 225 select HAVE_USER_RETURN_NOTIFIER 226 select HAVE_GENERIC_VDSO 227 select HOTPLUG_SMT if SMP 228 select IRQ_FORCED_THREADING 229 select NEED_SG_DMA_LENGTH 230 select PCI_DOMAINS if PCI 231 select PCI_LOCKLESS_CONFIG if PCI 232 select PERF_EVENTS 233 select RTC_LIB 234 select RTC_MC146818_LIB 235 select SPARSE_IRQ 236 select SRCU 237 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 238 select SYSCTL_EXCEPTION_TRACE 239 select THREAD_INFO_IN_TASK 240 select USER_STACKTRACE_SUPPORT 241 select VIRT_TO_BUS 242 select HAVE_ARCH_KCSAN if X86_64 243 select X86_FEATURE_NAMES if PROC_FS 244 select PROC_PID_ARCH_STATUS if PROC_FS 245 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 246 247config INSTRUCTION_DECODER 248 def_bool y 249 depends on KPROBES || PERF_EVENTS || UPROBES 250 251config OUTPUT_FORMAT 252 string 253 default "elf32-i386" if X86_32 254 default "elf64-x86-64" if X86_64 255 256config LOCKDEP_SUPPORT 257 def_bool y 258 259config STACKTRACE_SUPPORT 260 def_bool y 261 262config MMU 263 def_bool y 264 265config ARCH_MMAP_RND_BITS_MIN 266 default 28 if 64BIT 267 default 8 268 269config ARCH_MMAP_RND_BITS_MAX 270 default 32 if 64BIT 271 default 16 272 273config ARCH_MMAP_RND_COMPAT_BITS_MIN 274 default 8 275 276config ARCH_MMAP_RND_COMPAT_BITS_MAX 277 default 16 278 279config SBUS 280 bool 281 282config GENERIC_ISA_DMA 283 def_bool y 284 depends on ISA_DMA_API 285 286config GENERIC_BUG 287 def_bool y 288 depends on BUG 289 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 290 291config GENERIC_BUG_RELATIVE_POINTERS 292 bool 293 294config ARCH_MAY_HAVE_PC_FDC 295 def_bool y 296 depends on ISA_DMA_API 297 298config GENERIC_CALIBRATE_DELAY 299 def_bool y 300 301config ARCH_HAS_CPU_RELAX 302 def_bool y 303 304config ARCH_HAS_CACHE_LINE_SIZE 305 def_bool y 306 307config ARCH_HAS_FILTER_PGPROT 308 def_bool y 309 310config HAVE_SETUP_PER_CPU_AREA 311 def_bool y 312 313config NEED_PER_CPU_EMBED_FIRST_CHUNK 314 def_bool y 315 316config NEED_PER_CPU_PAGE_FIRST_CHUNK 317 def_bool y 318 319config ARCH_HIBERNATION_POSSIBLE 320 def_bool y 321 322config ARCH_SUSPEND_POSSIBLE 323 def_bool y 324 325config ARCH_WANT_GENERAL_HUGETLB 326 def_bool y 327 328config ZONE_DMA32 329 def_bool y if X86_64 330 331config AUDIT_ARCH 332 def_bool y if X86_64 333 334config ARCH_SUPPORTS_DEBUG_PAGEALLOC 335 def_bool y 336 337config KASAN_SHADOW_OFFSET 338 hex 339 depends on KASAN 340 default 0xdffffc0000000000 341 342config HAVE_INTEL_TXT 343 def_bool y 344 depends on INTEL_IOMMU && ACPI 345 346config X86_32_SMP 347 def_bool y 348 depends on X86_32 && SMP 349 350config X86_64_SMP 351 def_bool y 352 depends on X86_64 && SMP 353 354config X86_32_LAZY_GS 355 def_bool y 356 depends on X86_32 && !STACKPROTECTOR 357 358config ARCH_SUPPORTS_UPROBES 359 def_bool y 360 361config FIX_EARLYCON_MEM 362 def_bool y 363 364config DYNAMIC_PHYSICAL_MASK 365 bool 366 367config PGTABLE_LEVELS 368 int 369 default 5 if X86_5LEVEL 370 default 4 if X86_64 371 default 3 if X86_PAE 372 default 2 373 374config CC_HAS_SANE_STACKPROTECTOR 375 bool 376 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 377 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 378 help 379 We have to make sure stack protector is unconditionally disabled if 380 the compiler produces broken code. 381 382menu "Processor type and features" 383 384config ZONE_DMA 385 bool "DMA memory allocation support" if EXPERT 386 default y 387 help 388 DMA memory allocation support allows devices with less than 32-bit 389 addressing to allocate within the first 16MB of address space. 390 Disable if no such devices will be used. 391 392 If unsure, say Y. 393 394config SMP 395 bool "Symmetric multi-processing support" 396 help 397 This enables support for systems with more than one CPU. If you have 398 a system with only one CPU, say N. If you have a system with more 399 than one CPU, say Y. 400 401 If you say N here, the kernel will run on uni- and multiprocessor 402 machines, but will use only one CPU of a multiprocessor machine. If 403 you say Y here, the kernel will run on many, but not all, 404 uniprocessor machines. On a uniprocessor machine, the kernel 405 will run faster if you say N here. 406 407 Note that if you say Y here and choose architecture "586" or 408 "Pentium" under "Processor family", the kernel will not work on 486 409 architectures. Similarly, multiprocessor kernels for the "PPro" 410 architecture may not work on all Pentium based boards. 411 412 People using multiprocessor machines who say Y here should also say 413 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 414 Management" code will be disabled if you say Y here. 415 416 See also <file:Documentation/x86/i386/IO-APIC.rst>, 417 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 418 <http://www.tldp.org/docs.html#howto>. 419 420 If you don't know what to do here, say N. 421 422config X86_FEATURE_NAMES 423 bool "Processor feature human-readable names" if EMBEDDED 424 default y 425 help 426 This option compiles in a table of x86 feature bits and corresponding 427 names. This is required to support /proc/cpuinfo and a few kernel 428 messages. You can disable this to save space, at the expense of 429 making those few kernel messages show numeric feature bits instead. 430 431 If in doubt, say Y. 432 433config X86_X2APIC 434 bool "Support x2apic" 435 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 436 help 437 This enables x2apic support on CPUs that have this feature. 438 439 This allows 32-bit apic IDs (so it can support very large systems), 440 and accesses the local apic via MSRs not via mmio. 441 442 If you don't know what to do here, say N. 443 444config X86_MPPARSE 445 bool "Enable MPS table" if ACPI || SFI 446 default y 447 depends on X86_LOCAL_APIC 448 help 449 For old smp systems that do not have proper acpi support. Newer systems 450 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 451 452config GOLDFISH 453 def_bool y 454 depends on X86_GOLDFISH 455 456config X86_CPU_RESCTRL 457 bool "x86 CPU resource control support" 458 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 459 select KERNFS 460 select PROC_CPU_RESCTRL if PROC_FS 461 help 462 Enable x86 CPU resource control support. 463 464 Provide support for the allocation and monitoring of system resources 465 usage by the CPU. 466 467 Intel calls this Intel Resource Director Technology 468 (Intel(R) RDT). More information about RDT can be found in the 469 Intel x86 Architecture Software Developer Manual. 470 471 AMD calls this AMD Platform Quality of Service (AMD QoS). 472 More information about AMD QoS can be found in the AMD64 Technology 473 Platform Quality of Service Extensions manual. 474 475 Say N if unsure. 476 477if X86_32 478config X86_BIGSMP 479 bool "Support for big SMP systems with more than 8 CPUs" 480 depends on SMP 481 help 482 This option is needed for the systems that have more than 8 CPUs. 483 484config X86_EXTENDED_PLATFORM 485 bool "Support for extended (non-PC) x86 platforms" 486 default y 487 help 488 If you disable this option then the kernel will only support 489 standard PC platforms. (which covers the vast majority of 490 systems out there.) 491 492 If you enable this option then you'll be able to select support 493 for the following (non-PC) 32 bit x86 platforms: 494 Goldfish (Android emulator) 495 AMD Elan 496 RDC R-321x SoC 497 SGI 320/540 (Visual Workstation) 498 STA2X11-based (e.g. Northville) 499 Moorestown MID devices 500 501 If you have one of these systems, or if you want to build a 502 generic distribution kernel, say Y here - otherwise say N. 503endif 504 505if X86_64 506config X86_EXTENDED_PLATFORM 507 bool "Support for extended (non-PC) x86 platforms" 508 default y 509 help 510 If you disable this option then the kernel will only support 511 standard PC platforms. (which covers the vast majority of 512 systems out there.) 513 514 If you enable this option then you'll be able to select support 515 for the following (non-PC) 64 bit x86 platforms: 516 Numascale NumaChip 517 ScaleMP vSMP 518 SGI Ultraviolet 519 520 If you have one of these systems, or if you want to build a 521 generic distribution kernel, say Y here - otherwise say N. 522endif 523# This is an alphabetically sorted list of 64 bit extended platforms 524# Please maintain the alphabetic order if and when there are additions 525config X86_NUMACHIP 526 bool "Numascale NumaChip" 527 depends on X86_64 528 depends on X86_EXTENDED_PLATFORM 529 depends on NUMA 530 depends on SMP 531 depends on X86_X2APIC 532 depends on PCI_MMCONFIG 533 help 534 Adds support for Numascale NumaChip large-SMP systems. Needed to 535 enable more than ~168 cores. 536 If you don't have one of these, you should say N here. 537 538config X86_VSMP 539 bool "ScaleMP vSMP" 540 select HYPERVISOR_GUEST 541 select PARAVIRT 542 depends on X86_64 && PCI 543 depends on X86_EXTENDED_PLATFORM 544 depends on SMP 545 help 546 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 547 supposed to run on these EM64T-based machines. Only choose this option 548 if you have one of these machines. 549 550config X86_UV 551 bool "SGI Ultraviolet" 552 depends on X86_64 553 depends on X86_EXTENDED_PLATFORM 554 depends on NUMA 555 depends on EFI 556 depends on KEXEC_CORE 557 depends on X86_X2APIC 558 depends on PCI 559 help 560 This option is needed in order to support SGI Ultraviolet systems. 561 If you don't have one of these, you should say N here. 562 563# Following is an alphabetically sorted list of 32 bit extended platforms 564# Please maintain the alphabetic order if and when there are additions 565 566config X86_GOLDFISH 567 bool "Goldfish (Virtual Platform)" 568 depends on X86_EXTENDED_PLATFORM 569 help 570 Enable support for the Goldfish virtual platform used primarily 571 for Android development. Unless you are building for the Android 572 Goldfish emulator say N here. 573 574config X86_INTEL_CE 575 bool "CE4100 TV platform" 576 depends on PCI 577 depends on PCI_GODIRECT 578 depends on X86_IO_APIC 579 depends on X86_32 580 depends on X86_EXTENDED_PLATFORM 581 select X86_REBOOTFIXUPS 582 select OF 583 select OF_EARLY_FLATTREE 584 help 585 Select for the Intel CE media processor (CE4100) SOC. 586 This option compiles in support for the CE4100 SOC for settop 587 boxes and media devices. 588 589config X86_INTEL_MID 590 bool "Intel MID platform support" 591 depends on X86_EXTENDED_PLATFORM 592 depends on X86_PLATFORM_DEVICES 593 depends on PCI 594 depends on X86_64 || (PCI_GOANY && X86_32) 595 depends on X86_IO_APIC 596 select SFI 597 select I2C 598 select DW_APB_TIMER 599 select APB_TIMER 600 select INTEL_SCU_PCI 601 select MFD_INTEL_MSIC 602 help 603 Select to build a kernel capable of supporting Intel MID (Mobile 604 Internet Device) platform systems which do not have the PCI legacy 605 interfaces. If you are building for a PC class system say N here. 606 607 Intel MID platforms are based on an Intel processor and chipset which 608 consume less power than most of the x86 derivatives. 609 610config X86_INTEL_QUARK 611 bool "Intel Quark platform support" 612 depends on X86_32 613 depends on X86_EXTENDED_PLATFORM 614 depends on X86_PLATFORM_DEVICES 615 depends on X86_TSC 616 depends on PCI 617 depends on PCI_GOANY 618 depends on X86_IO_APIC 619 select IOSF_MBI 620 select INTEL_IMR 621 select COMMON_CLK 622 help 623 Select to include support for Quark X1000 SoC. 624 Say Y here if you have a Quark based system such as the Arduino 625 compatible Intel Galileo. 626 627config X86_INTEL_LPSS 628 bool "Intel Low Power Subsystem Support" 629 depends on X86 && ACPI && PCI 630 select COMMON_CLK 631 select PINCTRL 632 select IOSF_MBI 633 help 634 Select to build support for Intel Low Power Subsystem such as 635 found on Intel Lynxpoint PCH. Selecting this option enables 636 things like clock tree (common clock framework) and pincontrol 637 which are needed by the LPSS peripheral drivers. 638 639config X86_AMD_PLATFORM_DEVICE 640 bool "AMD ACPI2Platform devices support" 641 depends on ACPI 642 select COMMON_CLK 643 select PINCTRL 644 help 645 Select to interpret AMD specific ACPI device to platform device 646 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 647 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 648 implemented under PINCTRL subsystem. 649 650config IOSF_MBI 651 tristate "Intel SoC IOSF Sideband support for SoC platforms" 652 depends on PCI 653 help 654 This option enables sideband register access support for Intel SoC 655 platforms. On these platforms the IOSF sideband is used in lieu of 656 MSR's for some register accesses, mostly but not limited to thermal 657 and power. Drivers may query the availability of this device to 658 determine if they need the sideband in order to work on these 659 platforms. The sideband is available on the following SoC products. 660 This list is not meant to be exclusive. 661 - BayTrail 662 - Braswell 663 - Quark 664 665 You should say Y if you are running a kernel on one of these SoC's. 666 667config IOSF_MBI_DEBUG 668 bool "Enable IOSF sideband access through debugfs" 669 depends on IOSF_MBI && DEBUG_FS 670 help 671 Select this option to expose the IOSF sideband access registers (MCR, 672 MDR, MCRX) through debugfs to write and read register information from 673 different units on the SoC. This is most useful for obtaining device 674 state information for debug and analysis. As this is a general access 675 mechanism, users of this option would have specific knowledge of the 676 device they want to access. 677 678 If you don't require the option or are in doubt, say N. 679 680config X86_RDC321X 681 bool "RDC R-321x SoC" 682 depends on X86_32 683 depends on X86_EXTENDED_PLATFORM 684 select M486 685 select X86_REBOOTFIXUPS 686 help 687 This option is needed for RDC R-321x system-on-chip, also known 688 as R-8610-(G). 689 If you don't have one of these chips, you should say N here. 690 691config X86_32_NON_STANDARD 692 bool "Support non-standard 32-bit SMP architectures" 693 depends on X86_32 && SMP 694 depends on X86_EXTENDED_PLATFORM 695 help 696 This option compiles in the bigsmp and STA2X11 default 697 subarchitectures. It is intended for a generic binary 698 kernel. If you select them all, kernel will probe it one by 699 one and will fallback to default. 700 701# Alphabetically sorted list of Non standard 32 bit platforms 702 703config X86_SUPPORTS_MEMORY_FAILURE 704 def_bool y 705 # MCE code calls memory_failure(): 706 depends on X86_MCE 707 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 708 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 709 depends on X86_64 || !SPARSEMEM 710 select ARCH_SUPPORTS_MEMORY_FAILURE 711 712config STA2X11 713 bool "STA2X11 Companion Chip Support" 714 depends on X86_32_NON_STANDARD && PCI 715 select SWIOTLB 716 select MFD_STA2X11 717 select GPIOLIB 718 help 719 This adds support for boards based on the STA2X11 IO-Hub, 720 a.k.a. "ConneXt". The chip is used in place of the standard 721 PC chipset, so all "standard" peripherals are missing. If this 722 option is selected the kernel will still be able to boot on 723 standard PC machines. 724 725config X86_32_IRIS 726 tristate "Eurobraille/Iris poweroff module" 727 depends on X86_32 728 help 729 The Iris machines from EuroBraille do not have APM or ACPI support 730 to shut themselves down properly. A special I/O sequence is 731 needed to do so, which is what this module does at 732 kernel shutdown. 733 734 This is only for Iris machines from EuroBraille. 735 736 If unused, say N. 737 738config SCHED_OMIT_FRAME_POINTER 739 def_bool y 740 prompt "Single-depth WCHAN output" 741 depends on X86 742 help 743 Calculate simpler /proc/<PID>/wchan values. If this option 744 is disabled then wchan values will recurse back to the 745 caller function. This provides more accurate wchan values, 746 at the expense of slightly more scheduling overhead. 747 748 If in doubt, say "Y". 749 750menuconfig HYPERVISOR_GUEST 751 bool "Linux guest support" 752 help 753 Say Y here to enable options for running Linux under various hyper- 754 visors. This option enables basic hypervisor detection and platform 755 setup. 756 757 If you say N, all options in this submenu will be skipped and 758 disabled, and Linux guest support won't be built in. 759 760if HYPERVISOR_GUEST 761 762config PARAVIRT 763 bool "Enable paravirtualization code" 764 help 765 This changes the kernel so it can modify itself when it is run 766 under a hypervisor, potentially improving performance significantly 767 over full virtualization. However, when run without a hypervisor 768 the kernel is theoretically slower and slightly larger. 769 770config PARAVIRT_XXL 771 bool 772 773config PARAVIRT_DEBUG 774 bool "paravirt-ops debugging" 775 depends on PARAVIRT && DEBUG_KERNEL 776 help 777 Enable to debug paravirt_ops internals. Specifically, BUG if 778 a paravirt_op is missing when it is called. 779 780config PARAVIRT_SPINLOCKS 781 bool "Paravirtualization layer for spinlocks" 782 depends on PARAVIRT && SMP 783 help 784 Paravirtualized spinlocks allow a pvops backend to replace the 785 spinlock implementation with something virtualization-friendly 786 (for example, block the virtual CPU rather than spinning). 787 788 It has a minimal impact on native kernels and gives a nice performance 789 benefit on paravirtualized KVM / Xen kernels. 790 791 If you are unsure how to answer this question, answer Y. 792 793config X86_HV_CALLBACK_VECTOR 794 def_bool n 795 796source "arch/x86/xen/Kconfig" 797 798config KVM_GUEST 799 bool "KVM Guest support (including kvmclock)" 800 depends on PARAVIRT 801 select PARAVIRT_CLOCK 802 select ARCH_CPUIDLE_HALTPOLL 803 select X86_HV_CALLBACK_VECTOR 804 default y 805 help 806 This option enables various optimizations for running under the KVM 807 hypervisor. It includes a paravirtualized clock, so that instead 808 of relying on a PIT (or probably other) emulation by the 809 underlying device model, the host provides the guest with 810 timing infrastructure such as time of day, and system time 811 812config ARCH_CPUIDLE_HALTPOLL 813 def_bool n 814 prompt "Disable host haltpoll when loading haltpoll driver" 815 help 816 If virtualized under KVM, disable host haltpoll. 817 818config PVH 819 bool "Support for running PVH guests" 820 help 821 This option enables the PVH entry point for guest virtual machines 822 as specified in the x86/HVM direct boot ABI. 823 824config PARAVIRT_TIME_ACCOUNTING 825 bool "Paravirtual steal time accounting" 826 depends on PARAVIRT 827 help 828 Select this option to enable fine granularity task steal time 829 accounting. Time spent executing other tasks in parallel with 830 the current vCPU is discounted from the vCPU power. To account for 831 that, there can be a small performance impact. 832 833 If in doubt, say N here. 834 835config PARAVIRT_CLOCK 836 bool 837 838config JAILHOUSE_GUEST 839 bool "Jailhouse non-root cell support" 840 depends on X86_64 && PCI 841 select X86_PM_TIMER 842 help 843 This option allows to run Linux as guest in a Jailhouse non-root 844 cell. You can leave this option disabled if you only want to start 845 Jailhouse and run Linux afterwards in the root cell. 846 847config ACRN_GUEST 848 bool "ACRN Guest support" 849 depends on X86_64 850 select X86_HV_CALLBACK_VECTOR 851 help 852 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 853 a flexible, lightweight reference open-source hypervisor, built with 854 real-time and safety-criticality in mind. It is built for embedded 855 IOT with small footprint and real-time features. More details can be 856 found in https://projectacrn.org/. 857 858endif #HYPERVISOR_GUEST 859 860source "arch/x86/Kconfig.cpu" 861 862config HPET_TIMER 863 def_bool X86_64 864 prompt "HPET Timer Support" if X86_32 865 help 866 Use the IA-PC HPET (High Precision Event Timer) to manage 867 time in preference to the PIT and RTC, if a HPET is 868 present. 869 HPET is the next generation timer replacing legacy 8254s. 870 The HPET provides a stable time base on SMP 871 systems, unlike the TSC, but it is more expensive to access, 872 as it is off-chip. The interface used is documented 873 in the HPET spec, revision 1. 874 875 You can safely choose Y here. However, HPET will only be 876 activated if the platform and the BIOS support this feature. 877 Otherwise the 8254 will be used for timing services. 878 879 Choose N to continue using the legacy 8254 timer. 880 881config HPET_EMULATE_RTC 882 def_bool y 883 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 884 885config APB_TIMER 886 def_bool y if X86_INTEL_MID 887 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 888 select DW_APB_TIMER 889 depends on X86_INTEL_MID && SFI 890 help 891 APB timer is the replacement for 8254, HPET on X86 MID platforms. 892 The APBT provides a stable time base on SMP 893 systems, unlike the TSC, but it is more expensive to access, 894 as it is off-chip. APB timers are always running regardless of CPU 895 C states, they are used as per CPU clockevent device when possible. 896 897# Mark as expert because too many people got it wrong. 898# The code disables itself when not needed. 899config DMI 900 default y 901 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 902 bool "Enable DMI scanning" if EXPERT 903 help 904 Enabled scanning of DMI to identify machine quirks. Say Y 905 here unless you have verified that your setup is not 906 affected by entries in the DMI blacklist. Required by PNP 907 BIOS code. 908 909config GART_IOMMU 910 bool "Old AMD GART IOMMU support" 911 select DMA_OPS 912 select IOMMU_HELPER 913 select SWIOTLB 914 depends on X86_64 && PCI && AMD_NB 915 help 916 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 917 GART based hardware IOMMUs. 918 919 The GART supports full DMA access for devices with 32-bit access 920 limitations, on systems with more than 3 GB. This is usually needed 921 for USB, sound, many IDE/SATA chipsets and some other devices. 922 923 Newer systems typically have a modern AMD IOMMU, supported via 924 the CONFIG_AMD_IOMMU=y config option. 925 926 In normal configurations this driver is only active when needed: 927 there's more than 3 GB of memory and the system contains a 928 32-bit limited device. 929 930 If unsure, say Y. 931 932config MAXSMP 933 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 934 depends on X86_64 && SMP && DEBUG_KERNEL 935 select CPUMASK_OFFSTACK 936 help 937 Enable maximum number of CPUS and NUMA Nodes for this architecture. 938 If unsure, say N. 939 940# 941# The maximum number of CPUs supported: 942# 943# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 944# and which can be configured interactively in the 945# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 946# 947# The ranges are different on 32-bit and 64-bit kernels, depending on 948# hardware capabilities and scalability features of the kernel. 949# 950# ( If MAXSMP is enabled we just use the highest possible value and disable 951# interactive configuration. ) 952# 953 954config NR_CPUS_RANGE_BEGIN 955 int 956 default NR_CPUS_RANGE_END if MAXSMP 957 default 1 if !SMP 958 default 2 959 960config NR_CPUS_RANGE_END 961 int 962 depends on X86_32 963 default 64 if SMP && X86_BIGSMP 964 default 8 if SMP && !X86_BIGSMP 965 default 1 if !SMP 966 967config NR_CPUS_RANGE_END 968 int 969 depends on X86_64 970 default 8192 if SMP && CPUMASK_OFFSTACK 971 default 512 if SMP && !CPUMASK_OFFSTACK 972 default 1 if !SMP 973 974config NR_CPUS_DEFAULT 975 int 976 depends on X86_32 977 default 32 if X86_BIGSMP 978 default 8 if SMP 979 default 1 if !SMP 980 981config NR_CPUS_DEFAULT 982 int 983 depends on X86_64 984 default 8192 if MAXSMP 985 default 64 if SMP 986 default 1 if !SMP 987 988config NR_CPUS 989 int "Maximum number of CPUs" if SMP && !MAXSMP 990 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 991 default NR_CPUS_DEFAULT 992 help 993 This allows you to specify the maximum number of CPUs which this 994 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 995 supported value is 8192, otherwise the maximum value is 512. The 996 minimum value which makes sense is 2. 997 998 This is purely to save memory: each supported CPU adds about 8KB 999 to the kernel image. 1000 1001config SCHED_SMT 1002 def_bool y if SMP 1003 1004config SCHED_MC 1005 def_bool y 1006 prompt "Multi-core scheduler support" 1007 depends on SMP 1008 help 1009 Multi-core scheduler support improves the CPU scheduler's decision 1010 making when dealing with multi-core CPU chips at a cost of slightly 1011 increased overhead in some places. If unsure say N here. 1012 1013config SCHED_MC_PRIO 1014 bool "CPU core priorities scheduler support" 1015 depends on SCHED_MC && CPU_SUP_INTEL 1016 select X86_INTEL_PSTATE 1017 select CPU_FREQ 1018 default y 1019 help 1020 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1021 core ordering determined at manufacturing time, which allows 1022 certain cores to reach higher turbo frequencies (when running 1023 single threaded workloads) than others. 1024 1025 Enabling this kernel feature teaches the scheduler about 1026 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1027 scheduler's CPU selection logic accordingly, so that higher 1028 overall system performance can be achieved. 1029 1030 This feature will have no effect on CPUs without this feature. 1031 1032 If unsure say Y here. 1033 1034config UP_LATE_INIT 1035 def_bool y 1036 depends on !SMP && X86_LOCAL_APIC 1037 1038config X86_UP_APIC 1039 bool "Local APIC support on uniprocessors" if !PCI_MSI 1040 default PCI_MSI 1041 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1042 help 1043 A local APIC (Advanced Programmable Interrupt Controller) is an 1044 integrated interrupt controller in the CPU. If you have a single-CPU 1045 system which has a processor with a local APIC, you can say Y here to 1046 enable and use it. If you say Y here even though your machine doesn't 1047 have a local APIC, then the kernel will still run with no slowdown at 1048 all. The local APIC supports CPU-generated self-interrupts (timer, 1049 performance counters), and the NMI watchdog which detects hard 1050 lockups. 1051 1052config X86_UP_IOAPIC 1053 bool "IO-APIC support on uniprocessors" 1054 depends on X86_UP_APIC 1055 help 1056 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1057 SMP-capable replacement for PC-style interrupt controllers. Most 1058 SMP systems and many recent uniprocessor systems have one. 1059 1060 If you have a single-CPU system with an IO-APIC, you can say Y here 1061 to use it. If you say Y here even though your machine doesn't have 1062 an IO-APIC, then the kernel will still run with no slowdown at all. 1063 1064config X86_LOCAL_APIC 1065 def_bool y 1066 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1067 select IRQ_DOMAIN_HIERARCHY 1068 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1069 1070config X86_IO_APIC 1071 def_bool y 1072 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1073 1074config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1075 bool "Reroute for broken boot IRQs" 1076 depends on X86_IO_APIC 1077 help 1078 This option enables a workaround that fixes a source of 1079 spurious interrupts. This is recommended when threaded 1080 interrupt handling is used on systems where the generation of 1081 superfluous "boot interrupts" cannot be disabled. 1082 1083 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1084 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1085 kernel does during interrupt handling). On chipsets where this 1086 boot IRQ generation cannot be disabled, this workaround keeps 1087 the original IRQ line masked so that only the equivalent "boot 1088 IRQ" is delivered to the CPUs. The workaround also tells the 1089 kernel to set up the IRQ handler on the boot IRQ line. In this 1090 way only one interrupt is delivered to the kernel. Otherwise 1091 the spurious second interrupt may cause the kernel to bring 1092 down (vital) interrupt lines. 1093 1094 Only affects "broken" chipsets. Interrupt sharing may be 1095 increased on these systems. 1096 1097config X86_MCE 1098 bool "Machine Check / overheating reporting" 1099 select GENERIC_ALLOCATOR 1100 default y 1101 help 1102 Machine Check support allows the processor to notify the 1103 kernel if it detects a problem (e.g. overheating, data corruption). 1104 The action the kernel takes depends on the severity of the problem, 1105 ranging from warning messages to halting the machine. 1106 1107config X86_MCELOG_LEGACY 1108 bool "Support for deprecated /dev/mcelog character device" 1109 depends on X86_MCE 1110 help 1111 Enable support for /dev/mcelog which is needed by the old mcelog 1112 userspace logging daemon. Consider switching to the new generation 1113 rasdaemon solution. 1114 1115config X86_MCE_INTEL 1116 def_bool y 1117 prompt "Intel MCE features" 1118 depends on X86_MCE && X86_LOCAL_APIC 1119 help 1120 Additional support for intel specific MCE features such as 1121 the thermal monitor. 1122 1123config X86_MCE_AMD 1124 def_bool y 1125 prompt "AMD MCE features" 1126 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1127 help 1128 Additional support for AMD specific MCE features such as 1129 the DRAM Error Threshold. 1130 1131config X86_ANCIENT_MCE 1132 bool "Support for old Pentium 5 / WinChip machine checks" 1133 depends on X86_32 && X86_MCE 1134 help 1135 Include support for machine check handling on old Pentium 5 or WinChip 1136 systems. These typically need to be enabled explicitly on the command 1137 line. 1138 1139config X86_MCE_THRESHOLD 1140 depends on X86_MCE_AMD || X86_MCE_INTEL 1141 def_bool y 1142 1143config X86_MCE_INJECT 1144 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1145 tristate "Machine check injector support" 1146 help 1147 Provide support for injecting machine checks for testing purposes. 1148 If you don't know what a machine check is and you don't do kernel 1149 QA it is safe to say n. 1150 1151config X86_THERMAL_VECTOR 1152 def_bool y 1153 depends on X86_MCE_INTEL 1154 1155source "arch/x86/events/Kconfig" 1156 1157config X86_LEGACY_VM86 1158 bool "Legacy VM86 support" 1159 depends on X86_32 1160 help 1161 This option allows user programs to put the CPU into V8086 1162 mode, which is an 80286-era approximation of 16-bit real mode. 1163 1164 Some very old versions of X and/or vbetool require this option 1165 for user mode setting. Similarly, DOSEMU will use it if 1166 available to accelerate real mode DOS programs. However, any 1167 recent version of DOSEMU, X, or vbetool should be fully 1168 functional even without kernel VM86 support, as they will all 1169 fall back to software emulation. Nevertheless, if you are using 1170 a 16-bit DOS program where 16-bit performance matters, vm86 1171 mode might be faster than emulation and you might want to 1172 enable this option. 1173 1174 Note that any app that works on a 64-bit kernel is unlikely to 1175 need this option, as 64-bit kernels don't, and can't, support 1176 V8086 mode. This option is also unrelated to 16-bit protected 1177 mode and is not needed to run most 16-bit programs under Wine. 1178 1179 Enabling this option increases the complexity of the kernel 1180 and slows down exception handling a tiny bit. 1181 1182 If unsure, say N here. 1183 1184config VM86 1185 bool 1186 default X86_LEGACY_VM86 1187 1188config X86_16BIT 1189 bool "Enable support for 16-bit segments" if EXPERT 1190 default y 1191 depends on MODIFY_LDT_SYSCALL 1192 help 1193 This option is required by programs like Wine to run 16-bit 1194 protected mode legacy code on x86 processors. Disabling 1195 this option saves about 300 bytes on i386, or around 6K text 1196 plus 16K runtime memory on x86-64, 1197 1198config X86_ESPFIX32 1199 def_bool y 1200 depends on X86_16BIT && X86_32 1201 1202config X86_ESPFIX64 1203 def_bool y 1204 depends on X86_16BIT && X86_64 1205 1206config X86_VSYSCALL_EMULATION 1207 bool "Enable vsyscall emulation" if EXPERT 1208 default y 1209 depends on X86_64 1210 help 1211 This enables emulation of the legacy vsyscall page. Disabling 1212 it is roughly equivalent to booting with vsyscall=none, except 1213 that it will also disable the helpful warning if a program 1214 tries to use a vsyscall. With this option set to N, offending 1215 programs will just segfault, citing addresses of the form 1216 0xffffffffff600?00. 1217 1218 This option is required by many programs built before 2013, and 1219 care should be used even with newer programs if set to N. 1220 1221 Disabling this option saves about 7K of kernel size and 1222 possibly 4K of additional runtime pagetable memory. 1223 1224config X86_IOPL_IOPERM 1225 bool "IOPERM and IOPL Emulation" 1226 default y 1227 help 1228 This enables the ioperm() and iopl() syscalls which are necessary 1229 for legacy applications. 1230 1231 Legacy IOPL support is an overbroad mechanism which allows user 1232 space aside of accessing all 65536 I/O ports also to disable 1233 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1234 capabilities and permission from potentially active security 1235 modules. 1236 1237 The emulation restricts the functionality of the syscall to 1238 only allowing the full range I/O port access, but prevents the 1239 ability to disable interrupts from user space which would be 1240 granted if the hardware IOPL mechanism would be used. 1241 1242config TOSHIBA 1243 tristate "Toshiba Laptop support" 1244 depends on X86_32 1245 help 1246 This adds a driver to safely access the System Management Mode of 1247 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1248 not work on models with a Phoenix BIOS. The System Management Mode 1249 is used to set the BIOS and power saving options on Toshiba portables. 1250 1251 For information on utilities to make use of this driver see the 1252 Toshiba Linux utilities web site at: 1253 <http://www.buzzard.org.uk/toshiba/>. 1254 1255 Say Y if you intend to run this kernel on a Toshiba portable. 1256 Say N otherwise. 1257 1258config I8K 1259 tristate "Dell i8k legacy laptop support" 1260 depends on HWMON 1261 depends on PROC_FS 1262 select SENSORS_DELL_SMM 1263 help 1264 This option enables legacy /proc/i8k userspace interface in hwmon 1265 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1266 temperature and allows controlling fan speeds of Dell laptops via 1267 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1268 it reports also power and hotkey status. For fan speed control is 1269 needed userspace package i8kutils. 1270 1271 Say Y if you intend to run this kernel on old Dell laptops or want to 1272 use userspace package i8kutils. 1273 Say N otherwise. 1274 1275config X86_REBOOTFIXUPS 1276 bool "Enable X86 board specific fixups for reboot" 1277 depends on X86_32 1278 help 1279 This enables chipset and/or board specific fixups to be done 1280 in order to get reboot to work correctly. This is only needed on 1281 some combinations of hardware and BIOS. The symptom, for which 1282 this config is intended, is when reboot ends with a stalled/hung 1283 system. 1284 1285 Currently, the only fixup is for the Geode machines using 1286 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1287 1288 Say Y if you want to enable the fixup. Currently, it's safe to 1289 enable this option even if you don't need it. 1290 Say N otherwise. 1291 1292config MICROCODE 1293 bool "CPU microcode loading support" 1294 default y 1295 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1296 help 1297 If you say Y here, you will be able to update the microcode on 1298 Intel and AMD processors. The Intel support is for the IA32 family, 1299 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1300 AMD support is for families 0x10 and later. You will obviously need 1301 the actual microcode binary data itself which is not shipped with 1302 the Linux kernel. 1303 1304 The preferred method to load microcode from a detached initrd is described 1305 in Documentation/x86/microcode.rst. For that you need to enable 1306 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1307 initrd for microcode blobs. 1308 1309 In addition, you can build the microcode into the kernel. For that you 1310 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1311 config option. 1312 1313config MICROCODE_INTEL 1314 bool "Intel microcode loading support" 1315 depends on CPU_SUP_INTEL && MICROCODE 1316 default MICROCODE 1317 help 1318 This options enables microcode patch loading support for Intel 1319 processors. 1320 1321 For the current Intel microcode data package go to 1322 <https://downloadcenter.intel.com> and search for 1323 'Linux Processor Microcode Data File'. 1324 1325config MICROCODE_AMD 1326 bool "AMD microcode loading support" 1327 depends on CPU_SUP_AMD && MICROCODE 1328 help 1329 If you select this option, microcode patch loading support for AMD 1330 processors will be enabled. 1331 1332config MICROCODE_LATE_LOADING 1333 bool "Late microcode loading (DANGEROUS)" 1334 default n 1335 depends on MICROCODE 1336 help 1337 Loading microcode late, when the system is up and executing instructions 1338 is a tricky business and should be avoided if possible. Just the sequence 1339 of synchronizing all cores and SMT threads is one fragile dance which does 1340 not guarantee that cores might not softlock after the loading. Therefore, 1341 use this at your own risk. Late loading taints the kernel too. 1342 1343config X86_MSR 1344 tristate "/dev/cpu/*/msr - Model-specific register support" 1345 help 1346 This device gives privileged processes access to the x86 1347 Model-Specific Registers (MSRs). It is a character device with 1348 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1349 MSR accesses are directed to a specific CPU on multi-processor 1350 systems. 1351 1352config X86_CPUID 1353 tristate "/dev/cpu/*/cpuid - CPU information support" 1354 help 1355 This device gives processes access to the x86 CPUID instruction to 1356 be executed on a specific processor. It is a character device 1357 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1358 /dev/cpu/31/cpuid. 1359 1360choice 1361 prompt "High Memory Support" 1362 default HIGHMEM4G 1363 depends on X86_32 1364 1365config NOHIGHMEM 1366 bool "off" 1367 help 1368 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1369 However, the address space of 32-bit x86 processors is only 4 1370 Gigabytes large. That means that, if you have a large amount of 1371 physical memory, not all of it can be "permanently mapped" by the 1372 kernel. The physical memory that's not permanently mapped is called 1373 "high memory". 1374 1375 If you are compiling a kernel which will never run on a machine with 1376 more than 1 Gigabyte total physical RAM, answer "off" here (default 1377 choice and suitable for most users). This will result in a "3GB/1GB" 1378 split: 3GB are mapped so that each process sees a 3GB virtual memory 1379 space and the remaining part of the 4GB virtual memory space is used 1380 by the kernel to permanently map as much physical memory as 1381 possible. 1382 1383 If the machine has between 1 and 4 Gigabytes physical RAM, then 1384 answer "4GB" here. 1385 1386 If more than 4 Gigabytes is used then answer "64GB" here. This 1387 selection turns Intel PAE (Physical Address Extension) mode on. 1388 PAE implements 3-level paging on IA32 processors. PAE is fully 1389 supported by Linux, PAE mode is implemented on all recent Intel 1390 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1391 then the kernel will not boot on CPUs that don't support PAE! 1392 1393 The actual amount of total physical memory will either be 1394 auto detected or can be forced by using a kernel command line option 1395 such as "mem=256M". (Try "man bootparam" or see the documentation of 1396 your boot loader (lilo or loadlin) about how to pass options to the 1397 kernel at boot time.) 1398 1399 If unsure, say "off". 1400 1401config HIGHMEM4G 1402 bool "4GB" 1403 help 1404 Select this if you have a 32-bit processor and between 1 and 4 1405 gigabytes of physical RAM. 1406 1407config HIGHMEM64G 1408 bool "64GB" 1409 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1410 select X86_PAE 1411 help 1412 Select this if you have a 32-bit processor and more than 4 1413 gigabytes of physical RAM. 1414 1415endchoice 1416 1417choice 1418 prompt "Memory split" if EXPERT 1419 default VMSPLIT_3G 1420 depends on X86_32 1421 help 1422 Select the desired split between kernel and user memory. 1423 1424 If the address range available to the kernel is less than the 1425 physical memory installed, the remaining memory will be available 1426 as "high memory". Accessing high memory is a little more costly 1427 than low memory, as it needs to be mapped into the kernel first. 1428 Note that increasing the kernel address space limits the range 1429 available to user programs, making the address space there 1430 tighter. Selecting anything other than the default 3G/1G split 1431 will also likely make your kernel incompatible with binary-only 1432 kernel modules. 1433 1434 If you are not absolutely sure what you are doing, leave this 1435 option alone! 1436 1437 config VMSPLIT_3G 1438 bool "3G/1G user/kernel split" 1439 config VMSPLIT_3G_OPT 1440 depends on !X86_PAE 1441 bool "3G/1G user/kernel split (for full 1G low memory)" 1442 config VMSPLIT_2G 1443 bool "2G/2G user/kernel split" 1444 config VMSPLIT_2G_OPT 1445 depends on !X86_PAE 1446 bool "2G/2G user/kernel split (for full 2G low memory)" 1447 config VMSPLIT_1G 1448 bool "1G/3G user/kernel split" 1449endchoice 1450 1451config PAGE_OFFSET 1452 hex 1453 default 0xB0000000 if VMSPLIT_3G_OPT 1454 default 0x80000000 if VMSPLIT_2G 1455 default 0x78000000 if VMSPLIT_2G_OPT 1456 default 0x40000000 if VMSPLIT_1G 1457 default 0xC0000000 1458 depends on X86_32 1459 1460config HIGHMEM 1461 def_bool y 1462 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1463 1464config X86_PAE 1465 bool "PAE (Physical Address Extension) Support" 1466 depends on X86_32 && !HIGHMEM4G 1467 select PHYS_ADDR_T_64BIT 1468 select SWIOTLB 1469 help 1470 PAE is required for NX support, and furthermore enables 1471 larger swapspace support for non-overcommit purposes. It 1472 has the cost of more pagetable lookup overhead, and also 1473 consumes more pagetable space per process. 1474 1475config X86_5LEVEL 1476 bool "Enable 5-level page tables support" 1477 default y 1478 select DYNAMIC_MEMORY_LAYOUT 1479 select SPARSEMEM_VMEMMAP 1480 depends on X86_64 1481 help 1482 5-level paging enables access to larger address space: 1483 upto 128 PiB of virtual address space and 4 PiB of 1484 physical address space. 1485 1486 It will be supported by future Intel CPUs. 1487 1488 A kernel with the option enabled can be booted on machines that 1489 support 4- or 5-level paging. 1490 1491 See Documentation/x86/x86_64/5level-paging.rst for more 1492 information. 1493 1494 Say N if unsure. 1495 1496config X86_DIRECT_GBPAGES 1497 def_bool y 1498 depends on X86_64 1499 help 1500 Certain kernel features effectively disable kernel 1501 linear 1 GB mappings (even if the CPU otherwise 1502 supports them), so don't confuse the user by printing 1503 that we have them enabled. 1504 1505config X86_CPA_STATISTICS 1506 bool "Enable statistic for Change Page Attribute" 1507 depends on DEBUG_FS 1508 help 1509 Expose statistics about the Change Page Attribute mechanism, which 1510 helps to determine the effectiveness of preserving large and huge 1511 page mappings when mapping protections are changed. 1512 1513config AMD_MEM_ENCRYPT 1514 bool "AMD Secure Memory Encryption (SME) support" 1515 depends on X86_64 && CPU_SUP_AMD 1516 select DMA_COHERENT_POOL 1517 select DYNAMIC_PHYSICAL_MASK 1518 select ARCH_USE_MEMREMAP_PROT 1519 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1520 select INSTRUCTION_DECODER 1521 select ARCH_HAS_CC_PLATFORM 1522 help 1523 Say yes to enable support for the encryption of system memory. 1524 This requires an AMD processor that supports Secure Memory 1525 Encryption (SME). 1526 1527config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1528 bool "Activate AMD Secure Memory Encryption (SME) by default" 1529 depends on AMD_MEM_ENCRYPT 1530 help 1531 Say yes to have system memory encrypted by default if running on 1532 an AMD processor that supports Secure Memory Encryption (SME). 1533 1534 If set to Y, then the encryption of system memory can be 1535 deactivated with the mem_encrypt=off command line option. 1536 1537 If set to N, then the encryption of system memory can be 1538 activated with the mem_encrypt=on command line option. 1539 1540# Common NUMA Features 1541config NUMA 1542 bool "NUMA Memory Allocation and Scheduler Support" 1543 depends on SMP 1544 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1545 default y if X86_BIGSMP 1546 help 1547 Enable NUMA (Non-Uniform Memory Access) support. 1548 1549 The kernel will try to allocate memory used by a CPU on the 1550 local memory controller of the CPU and add some more 1551 NUMA awareness to the kernel. 1552 1553 For 64-bit this is recommended if the system is Intel Core i7 1554 (or later), AMD Opteron, or EM64T NUMA. 1555 1556 For 32-bit this is only needed if you boot a 32-bit 1557 kernel on a 64-bit NUMA platform. 1558 1559 Otherwise, you should say N. 1560 1561config AMD_NUMA 1562 def_bool y 1563 prompt "Old style AMD Opteron NUMA detection" 1564 depends on X86_64 && NUMA && PCI 1565 help 1566 Enable AMD NUMA node topology detection. You should say Y here if 1567 you have a multi processor AMD system. This uses an old method to 1568 read the NUMA configuration directly from the builtin Northbridge 1569 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1570 which also takes priority if both are compiled in. 1571 1572config X86_64_ACPI_NUMA 1573 def_bool y 1574 prompt "ACPI NUMA detection" 1575 depends on X86_64 && NUMA && ACPI && PCI 1576 select ACPI_NUMA 1577 help 1578 Enable ACPI SRAT based node topology detection. 1579 1580config NUMA_EMU 1581 bool "NUMA emulation" 1582 depends on NUMA 1583 help 1584 Enable NUMA emulation. A flat machine will be split 1585 into virtual nodes when booted with "numa=fake=N", where N is the 1586 number of nodes. This is only useful for debugging. 1587 1588config NODES_SHIFT 1589 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1590 range 1 10 1591 default "10" if MAXSMP 1592 default "6" if X86_64 1593 default "3" 1594 depends on NEED_MULTIPLE_NODES 1595 help 1596 Specify the maximum number of NUMA Nodes available on the target 1597 system. Increases memory reserved to accommodate various tables. 1598 1599config ARCH_FLATMEM_ENABLE 1600 def_bool y 1601 depends on X86_32 && !NUMA 1602 1603config ARCH_SPARSEMEM_ENABLE 1604 def_bool y 1605 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1606 select SPARSEMEM_STATIC if X86_32 1607 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1608 1609config ARCH_SPARSEMEM_DEFAULT 1610 def_bool X86_64 || (NUMA && X86_32) 1611 1612config ARCH_SELECT_MEMORY_MODEL 1613 def_bool y 1614 depends on ARCH_SPARSEMEM_ENABLE 1615 1616config ARCH_MEMORY_PROBE 1617 bool "Enable sysfs memory/probe interface" 1618 depends on X86_64 && MEMORY_HOTPLUG 1619 help 1620 This option enables a sysfs memory/probe interface for testing. 1621 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1622 If you are unsure how to answer this question, answer N. 1623 1624config ARCH_PROC_KCORE_TEXT 1625 def_bool y 1626 depends on X86_64 && PROC_KCORE 1627 1628config ILLEGAL_POINTER_VALUE 1629 hex 1630 default 0 if X86_32 1631 default 0xdead000000000000 if X86_64 1632 1633config X86_PMEM_LEGACY_DEVICE 1634 bool 1635 1636config X86_PMEM_LEGACY 1637 tristate "Support non-standard NVDIMMs and ADR protected memory" 1638 depends on PHYS_ADDR_T_64BIT 1639 depends on BLK_DEV 1640 select X86_PMEM_LEGACY_DEVICE 1641 select NUMA_KEEP_MEMINFO if NUMA 1642 select LIBNVDIMM 1643 help 1644 Treat memory marked using the non-standard e820 type of 12 as used 1645 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1646 The kernel will offer these regions to the 'pmem' driver so 1647 they can be used for persistent storage. 1648 1649 Say Y if unsure. 1650 1651config HIGHPTE 1652 bool "Allocate 3rd-level pagetables from highmem" 1653 depends on HIGHMEM 1654 help 1655 The VM uses one page table entry for each page of physical memory. 1656 For systems with a lot of RAM, this can be wasteful of precious 1657 low memory. Setting this option will put user-space page table 1658 entries in high memory. 1659 1660config X86_CHECK_BIOS_CORRUPTION 1661 bool "Check for low memory corruption" 1662 help 1663 Periodically check for memory corruption in low memory, which 1664 is suspected to be caused by BIOS. Even when enabled in the 1665 configuration, it is disabled at runtime. Enable it by 1666 setting "memory_corruption_check=1" on the kernel command 1667 line. By default it scans the low 64k of memory every 60 1668 seconds; see the memory_corruption_check_size and 1669 memory_corruption_check_period parameters in 1670 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1671 1672 When enabled with the default parameters, this option has 1673 almost no overhead, as it reserves a relatively small amount 1674 of memory and scans it infrequently. It both detects corruption 1675 and prevents it from affecting the running system. 1676 1677 It is, however, intended as a diagnostic tool; if repeatable 1678 BIOS-originated corruption always affects the same memory, 1679 you can use memmap= to prevent the kernel from using that 1680 memory. 1681 1682config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1683 bool "Set the default setting of memory_corruption_check" 1684 depends on X86_CHECK_BIOS_CORRUPTION 1685 default y 1686 help 1687 Set whether the default state of memory_corruption_check is 1688 on or off. 1689 1690config X86_RESERVE_LOW 1691 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1692 default 64 1693 range 4 640 1694 help 1695 Specify the amount of low memory to reserve for the BIOS. 1696 1697 The first page contains BIOS data structures that the kernel 1698 must not use, so that page must always be reserved. 1699 1700 By default we reserve the first 64K of physical RAM, as a 1701 number of BIOSes are known to corrupt that memory range 1702 during events such as suspend/resume or monitor cable 1703 insertion, so it must not be used by the kernel. 1704 1705 You can set this to 4 if you are absolutely sure that you 1706 trust the BIOS to get all its memory reservations and usages 1707 right. If you know your BIOS have problems beyond the 1708 default 64K area, you can set this to 640 to avoid using the 1709 entire low memory range. 1710 1711 If you have doubts about the BIOS (e.g. suspend/resume does 1712 not work or there's kernel crashes after certain hardware 1713 hotplug events) then you might want to enable 1714 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1715 typical corruption patterns. 1716 1717 Leave this to the default value of 64 if you are unsure. 1718 1719config MATH_EMULATION 1720 bool 1721 depends on MODIFY_LDT_SYSCALL 1722 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1723 help 1724 Linux can emulate a math coprocessor (used for floating point 1725 operations) if you don't have one. 486DX and Pentium processors have 1726 a math coprocessor built in, 486SX and 386 do not, unless you added 1727 a 487DX or 387, respectively. (The messages during boot time can 1728 give you some hints here ["man dmesg"].) Everyone needs either a 1729 coprocessor or this emulation. 1730 1731 If you don't have a math coprocessor, you need to say Y here; if you 1732 say Y here even though you have a coprocessor, the coprocessor will 1733 be used nevertheless. (This behavior can be changed with the kernel 1734 command line option "no387", which comes handy if your coprocessor 1735 is broken. Try "man bootparam" or see the documentation of your boot 1736 loader (lilo or loadlin) about how to pass options to the kernel at 1737 boot time.) This means that it is a good idea to say Y here if you 1738 intend to use this kernel on different machines. 1739 1740 More information about the internals of the Linux math coprocessor 1741 emulation can be found in <file:arch/x86/math-emu/README>. 1742 1743 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1744 kernel, it won't hurt. 1745 1746config MTRR 1747 def_bool y 1748 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1749 help 1750 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1751 the Memory Type Range Registers (MTRRs) may be used to control 1752 processor access to memory ranges. This is most useful if you have 1753 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1754 allows bus write transfers to be combined into a larger transfer 1755 before bursting over the PCI/AGP bus. This can increase performance 1756 of image write operations 2.5 times or more. Saying Y here creates a 1757 /proc/mtrr file which may be used to manipulate your processor's 1758 MTRRs. Typically the X server should use this. 1759 1760 This code has a reasonably generic interface so that similar 1761 control registers on other processors can be easily supported 1762 as well: 1763 1764 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1765 Registers (ARRs) which provide a similar functionality to MTRRs. For 1766 these, the ARRs are used to emulate the MTRRs. 1767 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1768 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1769 write-combining. All of these processors are supported by this code 1770 and it makes sense to say Y here if you have one of them. 1771 1772 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1773 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1774 can lead to all sorts of problems, so it's good to say Y here. 1775 1776 You can safely say Y even if your machine doesn't have MTRRs, you'll 1777 just add about 9 KB to your kernel. 1778 1779 See <file:Documentation/x86/mtrr.rst> for more information. 1780 1781config MTRR_SANITIZER 1782 def_bool y 1783 prompt "MTRR cleanup support" 1784 depends on MTRR 1785 help 1786 Convert MTRR layout from continuous to discrete, so X drivers can 1787 add writeback entries. 1788 1789 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1790 The largest mtrr entry size for a continuous block can be set with 1791 mtrr_chunk_size. 1792 1793 If unsure, say Y. 1794 1795config MTRR_SANITIZER_ENABLE_DEFAULT 1796 int "MTRR cleanup enable value (0-1)" 1797 range 0 1 1798 default "0" 1799 depends on MTRR_SANITIZER 1800 help 1801 Enable mtrr cleanup default value 1802 1803config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1804 int "MTRR cleanup spare reg num (0-7)" 1805 range 0 7 1806 default "1" 1807 depends on MTRR_SANITIZER 1808 help 1809 mtrr cleanup spare entries default, it can be changed via 1810 mtrr_spare_reg_nr=N on the kernel command line. 1811 1812config X86_PAT 1813 def_bool y 1814 prompt "x86 PAT support" if EXPERT 1815 depends on MTRR 1816 help 1817 Use PAT attributes to setup page level cache control. 1818 1819 PATs are the modern equivalents of MTRRs and are much more 1820 flexible than MTRRs. 1821 1822 Say N here if you see bootup problems (boot crash, boot hang, 1823 spontaneous reboots) or a non-working video driver. 1824 1825 If unsure, say Y. 1826 1827config ARCH_USES_PG_UNCACHED 1828 def_bool y 1829 depends on X86_PAT 1830 1831config ARCH_RANDOM 1832 def_bool y 1833 prompt "x86 architectural random number generator" if EXPERT 1834 help 1835 Enable the x86 architectural RDRAND instruction 1836 (Intel Bull Mountain technology) to generate random numbers. 1837 If supported, this is a high bandwidth, cryptographically 1838 secure hardware random number generator. 1839 1840config X86_SMAP 1841 def_bool y 1842 prompt "Supervisor Mode Access Prevention" if EXPERT 1843 help 1844 Supervisor Mode Access Prevention (SMAP) is a security 1845 feature in newer Intel processors. There is a small 1846 performance cost if this enabled and turned on; there is 1847 also a small increase in the kernel size if this is enabled. 1848 1849 If unsure, say Y. 1850 1851config X86_UMIP 1852 def_bool y 1853 prompt "User Mode Instruction Prevention" if EXPERT 1854 help 1855 User Mode Instruction Prevention (UMIP) is a security feature in 1856 some x86 processors. If enabled, a general protection fault is 1857 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1858 executed in user mode. These instructions unnecessarily expose 1859 information about the hardware state. 1860 1861 The vast majority of applications do not use these instructions. 1862 For the very few that do, software emulation is provided in 1863 specific cases in protected and virtual-8086 modes. Emulated 1864 results are dummy. 1865 1866config X86_INTEL_MEMORY_PROTECTION_KEYS 1867 prompt "Memory Protection Keys" 1868 def_bool y 1869 # Note: only available in 64-bit mode 1870 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1871 select ARCH_USES_HIGH_VMA_FLAGS 1872 select ARCH_HAS_PKEYS 1873 help 1874 Memory Protection Keys provides a mechanism for enforcing 1875 page-based protections, but without requiring modification of the 1876 page tables when an application changes protection domains. 1877 1878 For details, see Documentation/core-api/protection-keys.rst 1879 1880 If unsure, say y. 1881 1882choice 1883 prompt "TSX enable mode" 1884 depends on CPU_SUP_INTEL 1885 default X86_INTEL_TSX_MODE_OFF 1886 help 1887 Intel's TSX (Transactional Synchronization Extensions) feature 1888 allows to optimize locking protocols through lock elision which 1889 can lead to a noticeable performance boost. 1890 1891 On the other hand it has been shown that TSX can be exploited 1892 to form side channel attacks (e.g. TAA) and chances are there 1893 will be more of those attacks discovered in the future. 1894 1895 Therefore TSX is not enabled by default (aka tsx=off). An admin 1896 might override this decision by tsx=on the command line parameter. 1897 Even with TSX enabled, the kernel will attempt to enable the best 1898 possible TAA mitigation setting depending on the microcode available 1899 for the particular machine. 1900 1901 This option allows to set the default tsx mode between tsx=on, =off 1902 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1903 details. 1904 1905 Say off if not sure, auto if TSX is in use but it should be used on safe 1906 platforms or on if TSX is in use and the security aspect of tsx is not 1907 relevant. 1908 1909config X86_INTEL_TSX_MODE_OFF 1910 bool "off" 1911 help 1912 TSX is disabled if possible - equals to tsx=off command line parameter. 1913 1914config X86_INTEL_TSX_MODE_ON 1915 bool "on" 1916 help 1917 TSX is always enabled on TSX capable HW - equals the tsx=on command 1918 line parameter. 1919 1920config X86_INTEL_TSX_MODE_AUTO 1921 bool "auto" 1922 help 1923 TSX is enabled on TSX capable HW that is believed to be safe against 1924 side channel attacks- equals the tsx=auto command line parameter. 1925endchoice 1926 1927config EFI 1928 bool "EFI runtime service support" 1929 depends on ACPI 1930 select UCS2_STRING 1931 select EFI_RUNTIME_WRAPPERS 1932 select ARCH_USE_MEMREMAP_PROT 1933 help 1934 This enables the kernel to use EFI runtime services that are 1935 available (such as the EFI variable services). 1936 1937 This option is only useful on systems that have EFI firmware. 1938 In addition, you should use the latest ELILO loader available 1939 at <http://elilo.sourceforge.net> in order to take advantage 1940 of EFI runtime services. However, even with this option, the 1941 resultant kernel should continue to boot on existing non-EFI 1942 platforms. 1943 1944config EFI_STUB 1945 bool "EFI stub support" 1946 depends on EFI && !X86_USE_3DNOW 1947 select RELOCATABLE 1948 help 1949 This kernel feature allows a bzImage to be loaded directly 1950 by EFI firmware without the use of a bootloader. 1951 1952 See Documentation/admin-guide/efi-stub.rst for more information. 1953 1954config EFI_MIXED 1955 bool "EFI mixed-mode support" 1956 depends on EFI_STUB && X86_64 1957 help 1958 Enabling this feature allows a 64-bit kernel to be booted 1959 on a 32-bit firmware, provided that your CPU supports 64-bit 1960 mode. 1961 1962 Note that it is not possible to boot a mixed-mode enabled 1963 kernel via the EFI boot stub - a bootloader that supports 1964 the EFI handover protocol must be used. 1965 1966 If unsure, say N. 1967 1968source "kernel/Kconfig.hz" 1969 1970config KEXEC 1971 bool "kexec system call" 1972 select KEXEC_CORE 1973 help 1974 kexec is a system call that implements the ability to shutdown your 1975 current kernel, and to start another kernel. It is like a reboot 1976 but it is independent of the system firmware. And like a reboot 1977 you can start any kernel with it, not just Linux. 1978 1979 The name comes from the similarity to the exec system call. 1980 1981 It is an ongoing process to be certain the hardware in a machine 1982 is properly shutdown, so do not be surprised if this code does not 1983 initially work for you. As of this writing the exact hardware 1984 interface is strongly in flux, so no good recommendation can be 1985 made. 1986 1987config KEXEC_FILE 1988 bool "kexec file based system call" 1989 select KEXEC_CORE 1990 select BUILD_BIN2C 1991 depends on X86_64 1992 depends on CRYPTO=y 1993 depends on CRYPTO_SHA256=y 1994 help 1995 This is new version of kexec system call. This system call is 1996 file based and takes file descriptors as system call argument 1997 for kernel and initramfs as opposed to list of segments as 1998 accepted by previous system call. 1999 2000config ARCH_HAS_KEXEC_PURGATORY 2001 def_bool KEXEC_FILE 2002 2003config KEXEC_SIG 2004 bool "Verify kernel signature during kexec_file_load() syscall" 2005 depends on KEXEC_FILE 2006 help 2007 2008 This option makes the kexec_file_load() syscall check for a valid 2009 signature of the kernel image. The image can still be loaded without 2010 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2011 there's a signature that we can check, then it must be valid. 2012 2013 In addition to this option, you need to enable signature 2014 verification for the corresponding kernel image type being 2015 loaded in order for this to work. 2016 2017config KEXEC_SIG_FORCE 2018 bool "Require a valid signature in kexec_file_load() syscall" 2019 depends on KEXEC_SIG 2020 help 2021 This option makes kernel signature verification mandatory for 2022 the kexec_file_load() syscall. 2023 2024config KEXEC_BZIMAGE_VERIFY_SIG 2025 bool "Enable bzImage signature verification support" 2026 depends on KEXEC_SIG 2027 depends on SIGNED_PE_FILE_VERIFICATION 2028 select SYSTEM_TRUSTED_KEYRING 2029 help 2030 Enable bzImage signature verification support. 2031 2032config CRASH_DUMP 2033 bool "kernel crash dumps" 2034 depends on X86_64 || (X86_32 && HIGHMEM) 2035 help 2036 Generate crash dump after being started by kexec. 2037 This should be normally only set in special crash dump kernels 2038 which are loaded in the main kernel with kexec-tools into 2039 a specially reserved region and then later executed after 2040 a crash by kdump/kexec. The crash dump kernel must be compiled 2041 to a memory address not used by the main kernel or BIOS using 2042 PHYSICAL_START, or it must be built as a relocatable image 2043 (CONFIG_RELOCATABLE=y). 2044 For more details see Documentation/admin-guide/kdump/kdump.rst 2045 2046config KEXEC_JUMP 2047 bool "kexec jump" 2048 depends on KEXEC && HIBERNATION 2049 help 2050 Jump between original kernel and kexeced kernel and invoke 2051 code in physical address mode via KEXEC 2052 2053config PHYSICAL_START 2054 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2055 default "0x1000000" 2056 help 2057 This gives the physical address where the kernel is loaded. 2058 2059 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2060 bzImage will decompress itself to above physical address and 2061 run from there. Otherwise, bzImage will run from the address where 2062 it has been loaded by the boot loader and will ignore above physical 2063 address. 2064 2065 In normal kdump cases one does not have to set/change this option 2066 as now bzImage can be compiled as a completely relocatable image 2067 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2068 address. This option is mainly useful for the folks who don't want 2069 to use a bzImage for capturing the crash dump and want to use a 2070 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2071 to be specifically compiled to run from a specific memory area 2072 (normally a reserved region) and this option comes handy. 2073 2074 So if you are using bzImage for capturing the crash dump, 2075 leave the value here unchanged to 0x1000000 and set 2076 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2077 for capturing the crash dump change this value to start of 2078 the reserved region. In other words, it can be set based on 2079 the "X" value as specified in the "crashkernel=YM@XM" 2080 command line boot parameter passed to the panic-ed 2081 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2082 for more details about crash dumps. 2083 2084 Usage of bzImage for capturing the crash dump is recommended as 2085 one does not have to build two kernels. Same kernel can be used 2086 as production kernel and capture kernel. Above option should have 2087 gone away after relocatable bzImage support is introduced. But it 2088 is present because there are users out there who continue to use 2089 vmlinux for dump capture. This option should go away down the 2090 line. 2091 2092 Don't change this unless you know what you are doing. 2093 2094config RELOCATABLE 2095 bool "Build a relocatable kernel" 2096 default y 2097 help 2098 This builds a kernel image that retains relocation information 2099 so it can be loaded someplace besides the default 1MB. 2100 The relocations tend to make the kernel binary about 10% larger, 2101 but are discarded at runtime. 2102 2103 One use is for the kexec on panic case where the recovery kernel 2104 must live at a different physical address than the primary 2105 kernel. 2106 2107 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2108 it has been loaded at and the compile time physical address 2109 (CONFIG_PHYSICAL_START) is used as the minimum location. 2110 2111config RANDOMIZE_BASE 2112 bool "Randomize the address of the kernel image (KASLR)" 2113 depends on RELOCATABLE 2114 default y 2115 help 2116 In support of Kernel Address Space Layout Randomization (KASLR), 2117 this randomizes the physical address at which the kernel image 2118 is decompressed and the virtual address where the kernel 2119 image is mapped, as a security feature that deters exploit 2120 attempts relying on knowledge of the location of kernel 2121 code internals. 2122 2123 On 64-bit, the kernel physical and virtual addresses are 2124 randomized separately. The physical address will be anywhere 2125 between 16MB and the top of physical memory (up to 64TB). The 2126 virtual address will be randomized from 16MB up to 1GB (9 bits 2127 of entropy). Note that this also reduces the memory space 2128 available to kernel modules from 1.5GB to 1GB. 2129 2130 On 32-bit, the kernel physical and virtual addresses are 2131 randomized together. They will be randomized from 16MB up to 2132 512MB (8 bits of entropy). 2133 2134 Entropy is generated using the RDRAND instruction if it is 2135 supported. If RDTSC is supported, its value is mixed into 2136 the entropy pool as well. If neither RDRAND nor RDTSC are 2137 supported, then entropy is read from the i8254 timer. The 2138 usable entropy is limited by the kernel being built using 2139 2GB addressing, and that PHYSICAL_ALIGN must be at a 2140 minimum of 2MB. As a result, only 10 bits of entropy are 2141 theoretically possible, but the implementations are further 2142 limited due to memory layouts. 2143 2144 If unsure, say Y. 2145 2146# Relocation on x86 needs some additional build support 2147config X86_NEED_RELOCS 2148 def_bool y 2149 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2150 2151config PHYSICAL_ALIGN 2152 hex "Alignment value to which kernel should be aligned" 2153 default "0x200000" 2154 range 0x2000 0x1000000 if X86_32 2155 range 0x200000 0x1000000 if X86_64 2156 help 2157 This value puts the alignment restrictions on physical address 2158 where kernel is loaded and run from. Kernel is compiled for an 2159 address which meets above alignment restriction. 2160 2161 If bootloader loads the kernel at a non-aligned address and 2162 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2163 address aligned to above value and run from there. 2164 2165 If bootloader loads the kernel at a non-aligned address and 2166 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2167 load address and decompress itself to the address it has been 2168 compiled for and run from there. The address for which kernel is 2169 compiled already meets above alignment restrictions. Hence the 2170 end result is that kernel runs from a physical address meeting 2171 above alignment restrictions. 2172 2173 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2174 this value must be a multiple of 0x200000. 2175 2176 Don't change this unless you know what you are doing. 2177 2178config DYNAMIC_MEMORY_LAYOUT 2179 bool 2180 help 2181 This option makes base addresses of vmalloc and vmemmap as well as 2182 __PAGE_OFFSET movable during boot. 2183 2184config RANDOMIZE_MEMORY 2185 bool "Randomize the kernel memory sections" 2186 depends on X86_64 2187 depends on RANDOMIZE_BASE 2188 select DYNAMIC_MEMORY_LAYOUT 2189 default RANDOMIZE_BASE 2190 help 2191 Randomizes the base virtual address of kernel memory sections 2192 (physical memory mapping, vmalloc & vmemmap). This security feature 2193 makes exploits relying on predictable memory locations less reliable. 2194 2195 The order of allocations remains unchanged. Entropy is generated in 2196 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2197 configuration have in average 30,000 different possible virtual 2198 addresses for each memory section. 2199 2200 If unsure, say Y. 2201 2202config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2203 hex "Physical memory mapping padding" if EXPERT 2204 depends on RANDOMIZE_MEMORY 2205 default "0xa" if MEMORY_HOTPLUG 2206 default "0x0" 2207 range 0x1 0x40 if MEMORY_HOTPLUG 2208 range 0x0 0x40 2209 help 2210 Define the padding in terabytes added to the existing physical 2211 memory size during kernel memory randomization. It is useful 2212 for memory hotplug support but reduces the entropy available for 2213 address randomization. 2214 2215 If unsure, leave at the default value. 2216 2217config HOTPLUG_CPU 2218 def_bool y 2219 depends on SMP 2220 2221config BOOTPARAM_HOTPLUG_CPU0 2222 bool "Set default setting of cpu0_hotpluggable" 2223 depends on HOTPLUG_CPU 2224 help 2225 Set whether default state of cpu0_hotpluggable is on or off. 2226 2227 Say Y here to enable CPU0 hotplug by default. If this switch 2228 is turned on, there is no need to give cpu0_hotplug kernel 2229 parameter and the CPU0 hotplug feature is enabled by default. 2230 2231 Please note: there are two known CPU0 dependencies if you want 2232 to enable the CPU0 hotplug feature either by this switch or by 2233 cpu0_hotplug kernel parameter. 2234 2235 First, resume from hibernate or suspend always starts from CPU0. 2236 So hibernate and suspend are prevented if CPU0 is offline. 2237 2238 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2239 offline if any interrupt can not migrate out of CPU0. There may 2240 be other CPU0 dependencies. 2241 2242 Please make sure the dependencies are under your control before 2243 you enable this feature. 2244 2245 Say N if you don't want to enable CPU0 hotplug feature by default. 2246 You still can enable the CPU0 hotplug feature at boot by kernel 2247 parameter cpu0_hotplug. 2248 2249config DEBUG_HOTPLUG_CPU0 2250 def_bool n 2251 prompt "Debug CPU0 hotplug" 2252 depends on HOTPLUG_CPU 2253 help 2254 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2255 soon as possible and boots up userspace with CPU0 offlined. User 2256 can online CPU0 back after boot time. 2257 2258 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2259 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2260 compilation or giving cpu0_hotplug kernel parameter at boot. 2261 2262 If unsure, say N. 2263 2264config COMPAT_VDSO 2265 def_bool n 2266 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2267 depends on COMPAT_32 2268 help 2269 Certain buggy versions of glibc will crash if they are 2270 presented with a 32-bit vDSO that is not mapped at the address 2271 indicated in its segment table. 2272 2273 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2274 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2275 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2276 the only released version with the bug, but OpenSUSE 9 2277 contains a buggy "glibc 2.3.2". 2278 2279 The symptom of the bug is that everything crashes on startup, saying: 2280 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2281 2282 Saying Y here changes the default value of the vdso32 boot 2283 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2284 This works around the glibc bug but hurts performance. 2285 2286 If unsure, say N: if you are compiling your own kernel, you 2287 are unlikely to be using a buggy version of glibc. 2288 2289choice 2290 prompt "vsyscall table for legacy applications" 2291 depends on X86_64 2292 default LEGACY_VSYSCALL_XONLY 2293 help 2294 Legacy user code that does not know how to find the vDSO expects 2295 to be able to issue three syscalls by calling fixed addresses in 2296 kernel space. Since this location is not randomized with ASLR, 2297 it can be used to assist security vulnerability exploitation. 2298 2299 This setting can be changed at boot time via the kernel command 2300 line parameter vsyscall=[emulate|xonly|none]. 2301 2302 On a system with recent enough glibc (2.14 or newer) and no 2303 static binaries, you can say None without a performance penalty 2304 to improve security. 2305 2306 If unsure, select "Emulate execution only". 2307 2308 config LEGACY_VSYSCALL_EMULATE 2309 bool "Full emulation" 2310 help 2311 The kernel traps and emulates calls into the fixed vsyscall 2312 address mapping. This makes the mapping non-executable, but 2313 it still contains readable known contents, which could be 2314 used in certain rare security vulnerability exploits. This 2315 configuration is recommended when using legacy userspace 2316 that still uses vsyscalls along with legacy binary 2317 instrumentation tools that require code to be readable. 2318 2319 An example of this type of legacy userspace is running 2320 Pin on an old binary that still uses vsyscalls. 2321 2322 config LEGACY_VSYSCALL_XONLY 2323 bool "Emulate execution only" 2324 help 2325 The kernel traps and emulates calls into the fixed vsyscall 2326 address mapping and does not allow reads. This 2327 configuration is recommended when userspace might use the 2328 legacy vsyscall area but support for legacy binary 2329 instrumentation of legacy code is not needed. It mitigates 2330 certain uses of the vsyscall area as an ASLR-bypassing 2331 buffer. 2332 2333 config LEGACY_VSYSCALL_NONE 2334 bool "None" 2335 help 2336 There will be no vsyscall mapping at all. This will 2337 eliminate any risk of ASLR bypass due to the vsyscall 2338 fixed address mapping. Attempts to use the vsyscalls 2339 will be reported to dmesg, so that either old or 2340 malicious userspace programs can be identified. 2341 2342endchoice 2343 2344config CMDLINE_BOOL 2345 bool "Built-in kernel command line" 2346 help 2347 Allow for specifying boot arguments to the kernel at 2348 build time. On some systems (e.g. embedded ones), it is 2349 necessary or convenient to provide some or all of the 2350 kernel boot arguments with the kernel itself (that is, 2351 to not rely on the boot loader to provide them.) 2352 2353 To compile command line arguments into the kernel, 2354 set this option to 'Y', then fill in the 2355 boot arguments in CONFIG_CMDLINE. 2356 2357 Systems with fully functional boot loaders (i.e. non-embedded) 2358 should leave this option set to 'N'. 2359 2360config CMDLINE 2361 string "Built-in kernel command string" 2362 depends on CMDLINE_BOOL 2363 default "" 2364 help 2365 Enter arguments here that should be compiled into the kernel 2366 image and used at boot time. If the boot loader provides a 2367 command line at boot time, it is appended to this string to 2368 form the full kernel command line, when the system boots. 2369 2370 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2371 change this behavior. 2372 2373 In most cases, the command line (whether built-in or provided 2374 by the boot loader) should specify the device for the root 2375 file system. 2376 2377config CMDLINE_OVERRIDE 2378 bool "Built-in command line overrides boot loader arguments" 2379 depends on CMDLINE_BOOL && CMDLINE != "" 2380 help 2381 Set this option to 'Y' to have the kernel ignore the boot loader 2382 command line, and use ONLY the built-in command line. 2383 2384 This is used to work around broken boot loaders. This should 2385 be set to 'N' under normal conditions. 2386 2387config MODIFY_LDT_SYSCALL 2388 bool "Enable the LDT (local descriptor table)" if EXPERT 2389 default y 2390 help 2391 Linux can allow user programs to install a per-process x86 2392 Local Descriptor Table (LDT) using the modify_ldt(2) system 2393 call. This is required to run 16-bit or segmented code such as 2394 DOSEMU or some Wine programs. It is also used by some very old 2395 threading libraries. 2396 2397 Enabling this feature adds a small amount of overhead to 2398 context switches and increases the low-level kernel attack 2399 surface. Disabling it removes the modify_ldt(2) system call. 2400 2401 Saying 'N' here may make sense for embedded or server kernels. 2402 2403source "kernel/livepatch/Kconfig" 2404 2405endmenu 2406 2407config CC_HAS_SLS 2408 def_bool $(cc-option,-mharden-sls=all) 2409 2410config CC_HAS_RETURN_THUNK 2411 def_bool $(cc-option,-mfunction-return=thunk-extern) 2412 2413menuconfig SPECULATION_MITIGATIONS 2414 bool "Mitigations for speculative execution vulnerabilities" 2415 default y 2416 help 2417 Say Y here to enable options which enable mitigations for 2418 speculative execution hardware vulnerabilities. 2419 2420 If you say N, all mitigations will be disabled. You really 2421 should know what you are doing to say so. 2422 2423if SPECULATION_MITIGATIONS 2424 2425config PAGE_TABLE_ISOLATION 2426 bool "Remove the kernel mapping in user mode" 2427 default y 2428 depends on (X86_64 || X86_PAE) 2429 help 2430 This feature reduces the number of hardware side channels by 2431 ensuring that the majority of kernel addresses are not mapped 2432 into userspace. 2433 2434 See Documentation/x86/pti.rst for more details. 2435 2436config RETPOLINE 2437 bool "Avoid speculative indirect branches in kernel" 2438 default y 2439 help 2440 Compile kernel with the retpoline compiler options to guard against 2441 kernel-to-user data leaks by avoiding speculative indirect 2442 branches. Requires a compiler with -mindirect-branch=thunk-extern 2443 support for full protection. The kernel may run slower. 2444 2445config RETHUNK 2446 bool "Enable return-thunks" 2447 depends on RETPOLINE && CC_HAS_RETURN_THUNK 2448 default y if X86_64 2449 help 2450 Compile the kernel with the return-thunks compiler option to guard 2451 against kernel-to-user data leaks by avoiding return speculation. 2452 Requires a compiler with -mfunction-return=thunk-extern 2453 support for full protection. The kernel may run slower. 2454 2455config CPU_UNRET_ENTRY 2456 bool "Enable UNRET on kernel entry" 2457 depends on CPU_SUP_AMD && RETHUNK && X86_64 2458 default y 2459 help 2460 Compile the kernel with support for the retbleed=unret mitigation. 2461 2462config CPU_IBPB_ENTRY 2463 bool "Enable IBPB on kernel entry" 2464 depends on CPU_SUP_AMD && X86_64 2465 default y 2466 help 2467 Compile the kernel with support for the retbleed=ibpb mitigation. 2468 2469config CPU_IBRS_ENTRY 2470 bool "Enable IBRS on kernel entry" 2471 depends on CPU_SUP_INTEL && X86_64 2472 default y 2473 help 2474 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2475 This mitigates both spectre_v2 and retbleed at great cost to 2476 performance. 2477 2478config SLS 2479 bool "Mitigate Straight-Line-Speculation" 2480 depends on CC_HAS_SLS && X86_64 2481 default n 2482 help 2483 Compile the kernel with straight-line-speculation options to guard 2484 against straight line speculation. The kernel image might be slightly 2485 larger. 2486 2487endif 2488 2489config ARCH_HAS_ADD_PAGES 2490 def_bool y 2491 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2492 2493config ARCH_ENABLE_MEMORY_HOTPLUG 2494 def_bool y 2495 depends on X86_64 || (X86_32 && HIGHMEM) 2496 2497config ARCH_ENABLE_MEMORY_HOTREMOVE 2498 def_bool y 2499 depends on MEMORY_HOTPLUG 2500 2501config USE_PERCPU_NUMA_NODE_ID 2502 def_bool y 2503 depends on NUMA 2504 2505config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2506 def_bool y 2507 depends on X86_64 || X86_PAE 2508 2509config ARCH_ENABLE_HUGEPAGE_MIGRATION 2510 def_bool y 2511 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2512 2513config ARCH_ENABLE_THP_MIGRATION 2514 def_bool y 2515 depends on X86_64 && TRANSPARENT_HUGEPAGE 2516 2517menu "Power management and ACPI options" 2518 2519config ARCH_HIBERNATION_HEADER 2520 def_bool y 2521 depends on HIBERNATION 2522 2523source "kernel/power/Kconfig" 2524 2525source "drivers/acpi/Kconfig" 2526 2527source "drivers/sfi/Kconfig" 2528 2529config X86_APM_BOOT 2530 def_bool y 2531 depends on APM 2532 2533menuconfig APM 2534 tristate "APM (Advanced Power Management) BIOS support" 2535 depends on X86_32 && PM_SLEEP 2536 help 2537 APM is a BIOS specification for saving power using several different 2538 techniques. This is mostly useful for battery powered laptops with 2539 APM compliant BIOSes. If you say Y here, the system time will be 2540 reset after a RESUME operation, the /proc/apm device will provide 2541 battery status information, and user-space programs will receive 2542 notification of APM "events" (e.g. battery status change). 2543 2544 If you select "Y" here, you can disable actual use of the APM 2545 BIOS by passing the "apm=off" option to the kernel at boot time. 2546 2547 Note that the APM support is almost completely disabled for 2548 machines with more than one CPU. 2549 2550 In order to use APM, you will need supporting software. For location 2551 and more information, read <file:Documentation/power/apm-acpi.rst> 2552 and the Battery Powered Linux mini-HOWTO, available from 2553 <http://www.tldp.org/docs.html#howto>. 2554 2555 This driver does not spin down disk drives (see the hdparm(8) 2556 manpage ("man 8 hdparm") for that), and it doesn't turn off 2557 VESA-compliant "green" monitors. 2558 2559 This driver does not support the TI 4000M TravelMate and the ACER 2560 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2561 desktop machines also don't have compliant BIOSes, and this driver 2562 may cause those machines to panic during the boot phase. 2563 2564 Generally, if you don't have a battery in your machine, there isn't 2565 much point in using this driver and you should say N. If you get 2566 random kernel OOPSes or reboots that don't seem to be related to 2567 anything, try disabling/enabling this option (or disabling/enabling 2568 APM in your BIOS). 2569 2570 Some other things you should try when experiencing seemingly random, 2571 "weird" problems: 2572 2573 1) make sure that you have enough swap space and that it is 2574 enabled. 2575 2) pass the "no-hlt" option to the kernel 2576 3) switch on floating point emulation in the kernel and pass 2577 the "no387" option to the kernel 2578 4) pass the "floppy=nodma" option to the kernel 2579 5) pass the "mem=4M" option to the kernel (thereby disabling 2580 all but the first 4 MB of RAM) 2581 6) make sure that the CPU is not over clocked. 2582 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2583 8) disable the cache from your BIOS settings 2584 9) install a fan for the video card or exchange video RAM 2585 10) install a better fan for the CPU 2586 11) exchange RAM chips 2587 12) exchange the motherboard. 2588 2589 To compile this driver as a module, choose M here: the 2590 module will be called apm. 2591 2592if APM 2593 2594config APM_IGNORE_USER_SUSPEND 2595 bool "Ignore USER SUSPEND" 2596 help 2597 This option will ignore USER SUSPEND requests. On machines with a 2598 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2599 series notebooks, it is necessary to say Y because of a BIOS bug. 2600 2601config APM_DO_ENABLE 2602 bool "Enable PM at boot time" 2603 help 2604 Enable APM features at boot time. From page 36 of the APM BIOS 2605 specification: "When disabled, the APM BIOS does not automatically 2606 power manage devices, enter the Standby State, enter the Suspend 2607 State, or take power saving steps in response to CPU Idle calls." 2608 This driver will make CPU Idle calls when Linux is idle (unless this 2609 feature is turned off -- see "Do CPU IDLE calls", below). This 2610 should always save battery power, but more complicated APM features 2611 will be dependent on your BIOS implementation. You may need to turn 2612 this option off if your computer hangs at boot time when using APM 2613 support, or if it beeps continuously instead of suspending. Turn 2614 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2615 T400CDT. This is off by default since most machines do fine without 2616 this feature. 2617 2618config APM_CPU_IDLE 2619 depends on CPU_IDLE 2620 bool "Make CPU Idle calls when idle" 2621 help 2622 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2623 On some machines, this can activate improved power savings, such as 2624 a slowed CPU clock rate, when the machine is idle. These idle calls 2625 are made after the idle loop has run for some length of time (e.g., 2626 333 mS). On some machines, this will cause a hang at boot time or 2627 whenever the CPU becomes idle. (On machines with more than one CPU, 2628 this option does nothing.) 2629 2630config APM_DISPLAY_BLANK 2631 bool "Enable console blanking using APM" 2632 help 2633 Enable console blanking using the APM. Some laptops can use this to 2634 turn off the LCD backlight when the screen blanker of the Linux 2635 virtual console blanks the screen. Note that this is only used by 2636 the virtual console screen blanker, and won't turn off the backlight 2637 when using the X Window system. This also doesn't have anything to 2638 do with your VESA-compliant power-saving monitor. Further, this 2639 option doesn't work for all laptops -- it might not turn off your 2640 backlight at all, or it might print a lot of errors to the console, 2641 especially if you are using gpm. 2642 2643config APM_ALLOW_INTS 2644 bool "Allow interrupts during APM BIOS calls" 2645 help 2646 Normally we disable external interrupts while we are making calls to 2647 the APM BIOS as a measure to lessen the effects of a badly behaving 2648 BIOS implementation. The BIOS should reenable interrupts if it 2649 needs to. Unfortunately, some BIOSes do not -- especially those in 2650 many of the newer IBM Thinkpads. If you experience hangs when you 2651 suspend, try setting this to Y. Otherwise, say N. 2652 2653endif # APM 2654 2655source "drivers/cpufreq/Kconfig" 2656 2657source "drivers/cpuidle/Kconfig" 2658 2659source "drivers/idle/Kconfig" 2660 2661endmenu 2662 2663 2664menu "Bus options (PCI etc.)" 2665 2666choice 2667 prompt "PCI access mode" 2668 depends on X86_32 && PCI 2669 default PCI_GOANY 2670 help 2671 On PCI systems, the BIOS can be used to detect the PCI devices and 2672 determine their configuration. However, some old PCI motherboards 2673 have BIOS bugs and may crash if this is done. Also, some embedded 2674 PCI-based systems don't have any BIOS at all. Linux can also try to 2675 detect the PCI hardware directly without using the BIOS. 2676 2677 With this option, you can specify how Linux should detect the 2678 PCI devices. If you choose "BIOS", the BIOS will be used, 2679 if you choose "Direct", the BIOS won't be used, and if you 2680 choose "MMConfig", then PCI Express MMCONFIG will be used. 2681 If you choose "Any", the kernel will try MMCONFIG, then the 2682 direct access method and falls back to the BIOS if that doesn't 2683 work. If unsure, go with the default, which is "Any". 2684 2685config PCI_GOBIOS 2686 bool "BIOS" 2687 2688config PCI_GOMMCONFIG 2689 bool "MMConfig" 2690 2691config PCI_GODIRECT 2692 bool "Direct" 2693 2694config PCI_GOOLPC 2695 bool "OLPC XO-1" 2696 depends on OLPC 2697 2698config PCI_GOANY 2699 bool "Any" 2700 2701endchoice 2702 2703config PCI_BIOS 2704 def_bool y 2705 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2706 2707# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2708config PCI_DIRECT 2709 def_bool y 2710 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2711 2712config PCI_MMCONFIG 2713 bool "Support mmconfig PCI config space access" if X86_64 2714 default y 2715 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2716 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2717 2718config PCI_OLPC 2719 def_bool y 2720 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2721 2722config PCI_XEN 2723 def_bool y 2724 depends on PCI && XEN 2725 select SWIOTLB_XEN 2726 2727config MMCONF_FAM10H 2728 def_bool y 2729 depends on X86_64 && PCI_MMCONFIG && ACPI 2730 2731config PCI_CNB20LE_QUIRK 2732 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2733 depends on PCI 2734 help 2735 Read the PCI windows out of the CNB20LE host bridge. This allows 2736 PCI hotplug to work on systems with the CNB20LE chipset which do 2737 not have ACPI. 2738 2739 There's no public spec for this chipset, and this functionality 2740 is known to be incomplete. 2741 2742 You should say N unless you know you need this. 2743 2744config ISA_BUS 2745 bool "ISA bus support on modern systems" if EXPERT 2746 help 2747 Expose ISA bus device drivers and options available for selection and 2748 configuration. Enable this option if your target machine has an ISA 2749 bus. ISA is an older system, displaced by PCI and newer bus 2750 architectures -- if your target machine is modern, it probably does 2751 not have an ISA bus. 2752 2753 If unsure, say N. 2754 2755# x86_64 have no ISA slots, but can have ISA-style DMA. 2756config ISA_DMA_API 2757 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2758 default y 2759 help 2760 Enables ISA-style DMA support for devices requiring such controllers. 2761 If unsure, say Y. 2762 2763if X86_32 2764 2765config ISA 2766 bool "ISA support" 2767 help 2768 Find out whether you have ISA slots on your motherboard. ISA is the 2769 name of a bus system, i.e. the way the CPU talks to the other stuff 2770 inside your box. Other bus systems are PCI, EISA, MicroChannel 2771 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2772 newer boards don't support it. If you have ISA, say Y, otherwise N. 2773 2774config SCx200 2775 tristate "NatSemi SCx200 support" 2776 help 2777 This provides basic support for National Semiconductor's 2778 (now AMD's) Geode processors. The driver probes for the 2779 PCI-IDs of several on-chip devices, so its a good dependency 2780 for other scx200_* drivers. 2781 2782 If compiled as a module, the driver is named scx200. 2783 2784config SCx200HR_TIMER 2785 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2786 depends on SCx200 2787 default y 2788 help 2789 This driver provides a clocksource built upon the on-chip 2790 27MHz high-resolution timer. Its also a workaround for 2791 NSC Geode SC-1100's buggy TSC, which loses time when the 2792 processor goes idle (as is done by the scheduler). The 2793 other workaround is idle=poll boot option. 2794 2795config OLPC 2796 bool "One Laptop Per Child support" 2797 depends on !X86_PAE 2798 select GPIOLIB 2799 select OF 2800 select OF_PROMTREE 2801 select IRQ_DOMAIN 2802 select OLPC_EC 2803 help 2804 Add support for detecting the unique features of the OLPC 2805 XO hardware. 2806 2807config OLPC_XO1_PM 2808 bool "OLPC XO-1 Power Management" 2809 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2810 help 2811 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2812 2813config OLPC_XO1_RTC 2814 bool "OLPC XO-1 Real Time Clock" 2815 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2816 help 2817 Add support for the XO-1 real time clock, which can be used as a 2818 programmable wakeup source. 2819 2820config OLPC_XO1_SCI 2821 bool "OLPC XO-1 SCI extras" 2822 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2823 depends on INPUT=y 2824 select POWER_SUPPLY 2825 help 2826 Add support for SCI-based features of the OLPC XO-1 laptop: 2827 - EC-driven system wakeups 2828 - Power button 2829 - Ebook switch 2830 - Lid switch 2831 - AC adapter status updates 2832 - Battery status updates 2833 2834config OLPC_XO15_SCI 2835 bool "OLPC XO-1.5 SCI extras" 2836 depends on OLPC && ACPI 2837 select POWER_SUPPLY 2838 help 2839 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2840 - EC-driven system wakeups 2841 - AC adapter status updates 2842 - Battery status updates 2843 2844config ALIX 2845 bool "PCEngines ALIX System Support (LED setup)" 2846 select GPIOLIB 2847 help 2848 This option enables system support for the PCEngines ALIX. 2849 At present this just sets up LEDs for GPIO control on 2850 ALIX2/3/6 boards. However, other system specific setup should 2851 get added here. 2852 2853 Note: You must still enable the drivers for GPIO and LED support 2854 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2855 2856 Note: You have to set alix.force=1 for boards with Award BIOS. 2857 2858config NET5501 2859 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2860 select GPIOLIB 2861 help 2862 This option enables system support for the Soekris Engineering net5501. 2863 2864config GEOS 2865 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2866 select GPIOLIB 2867 depends on DMI 2868 help 2869 This option enables system support for the Traverse Technologies GEOS. 2870 2871config TS5500 2872 bool "Technologic Systems TS-5500 platform support" 2873 depends on MELAN 2874 select CHECK_SIGNATURE 2875 select NEW_LEDS 2876 select LEDS_CLASS 2877 help 2878 This option enables system support for the Technologic Systems TS-5500. 2879 2880endif # X86_32 2881 2882config AMD_NB 2883 def_bool y 2884 depends on CPU_SUP_AMD && PCI 2885 2886config X86_SYSFB 2887 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2888 help 2889 Firmwares often provide initial graphics framebuffers so the BIOS, 2890 bootloader or kernel can show basic video-output during boot for 2891 user-guidance and debugging. Historically, x86 used the VESA BIOS 2892 Extensions and EFI-framebuffers for this, which are mostly limited 2893 to x86. 2894 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2895 framebuffers so the new generic system-framebuffer drivers can be 2896 used on x86. If the framebuffer is not compatible with the generic 2897 modes, it is advertised as fallback platform framebuffer so legacy 2898 drivers like efifb, vesafb and uvesafb can pick it up. 2899 If this option is not selected, all system framebuffers are always 2900 marked as fallback platform framebuffers as usual. 2901 2902 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2903 not be able to pick up generic system framebuffers if this option 2904 is selected. You are highly encouraged to enable simplefb as 2905 replacement if you select this option. simplefb can correctly deal 2906 with generic system framebuffers. But you should still keep vesafb 2907 and others enabled as fallback if a system framebuffer is 2908 incompatible with simplefb. 2909 2910 If unsure, say Y. 2911 2912endmenu 2913 2914 2915menu "Binary Emulations" 2916 2917config IA32_EMULATION 2918 bool "IA32 Emulation" 2919 depends on X86_64 2920 select ARCH_WANT_OLD_COMPAT_IPC 2921 select BINFMT_ELF 2922 select COMPAT_BINFMT_ELF 2923 select COMPAT_OLD_SIGACTION 2924 help 2925 Include code to run legacy 32-bit programs under a 2926 64-bit kernel. You should likely turn this on, unless you're 2927 100% sure that you don't have any 32-bit programs left. 2928 2929config IA32_AOUT 2930 tristate "IA32 a.out support" 2931 depends on IA32_EMULATION 2932 depends on BROKEN 2933 help 2934 Support old a.out binaries in the 32bit emulation. 2935 2936config X86_X32 2937 bool "x32 ABI for 64-bit mode" 2938 depends on X86_64 2939 # llvm-objcopy does not convert x86_64 .note.gnu.property or 2940 # compressed debug sections to x86_x32 properly: 2941 # https://github.com/ClangBuiltLinux/linux/issues/514 2942 # https://github.com/ClangBuiltLinux/linux/issues/1141 2943 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2944 help 2945 Include code to run binaries for the x32 native 32-bit ABI 2946 for 64-bit processors. An x32 process gets access to the 2947 full 64-bit register file and wide data path while leaving 2948 pointers at 32 bits for smaller memory footprint. 2949 2950 You will need a recent binutils (2.22 or later) with 2951 elf32_x86_64 support enabled to compile a kernel with this 2952 option set. 2953 2954config COMPAT_32 2955 def_bool y 2956 depends on IA32_EMULATION || X86_32 2957 select HAVE_UID16 2958 select OLD_SIGSUSPEND3 2959 2960config COMPAT 2961 def_bool y 2962 depends on IA32_EMULATION || X86_X32 2963 2964if COMPAT 2965config COMPAT_FOR_U64_ALIGNMENT 2966 def_bool y 2967 2968config SYSVIPC_COMPAT 2969 def_bool y 2970 depends on SYSVIPC 2971endif 2972 2973endmenu 2974 2975 2976config HAVE_ATOMIC_IOMAP 2977 def_bool y 2978 depends on X86_32 2979 2980source "drivers/firmware/Kconfig" 2981 2982source "arch/x86/kvm/Kconfig" 2983 2984source "arch/x86/Kconfig.assembler" 2985