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_CPU_FINALIZE_INIT 63 select ARCH_HAS_DEBUG_VIRTUAL 64 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 65 select ARCH_HAS_DEVMEM_IS_ALLOWED 66 select ARCH_HAS_EARLY_DEBUG if KGDB 67 select ARCH_HAS_ELF_RANDOMIZE 68 select ARCH_HAS_FAST_MULTIPLIER 69 select ARCH_HAS_FILTER_PGPROT 70 select ARCH_HAS_FORTIFY_SOURCE 71 select ARCH_HAS_GCOV_PROFILE_ALL 72 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 73 select ARCH_HAS_MEM_ENCRYPT 74 select ARCH_HAS_MEMBARRIER_SYNC_CORE 75 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 76 select ARCH_HAS_PMEM_API if X86_64 77 select ARCH_HAS_PTE_DEVMAP if X86_64 78 select ARCH_HAS_PTE_SPECIAL 79 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 80 select ARCH_HAS_COPY_MC if X86_64 81 select ARCH_HAS_SET_MEMORY 82 select ARCH_HAS_SET_DIRECT_MAP 83 select ARCH_HAS_STRICT_KERNEL_RWX 84 select ARCH_HAS_STRICT_MODULE_RWX 85 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 86 select ARCH_HAS_SYSCALL_WRAPPER 87 select ARCH_HAS_UBSAN_SANITIZE_ALL 88 select ARCH_HAS_DEBUG_WX 89 select ARCH_HAVE_NMI_SAFE_CMPXCHG 90 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 91 select ARCH_MIGHT_HAVE_PC_PARPORT 92 select ARCH_MIGHT_HAVE_PC_SERIO 93 select ARCH_STACKWALK 94 select ARCH_SUPPORTS_ACPI 95 select ARCH_SUPPORTS_ATOMIC_RMW 96 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 97 select ARCH_USE_BUILTIN_BSWAP 98 select ARCH_USE_QUEUED_RWLOCKS 99 select ARCH_USE_QUEUED_SPINLOCKS 100 select ARCH_USE_SYM_ANNOTATIONS 101 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 102 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 103 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 104 select ARCH_WANT_HUGE_PMD_SHARE 105 select ARCH_WANT_LD_ORPHAN_WARN 106 select ARCH_WANTS_THP_SWAP if X86_64 107 select BUILDTIME_TABLE_SORT 108 select CLKEVT_I8253 109 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 110 select CLOCKSOURCE_WATCHDOG 111 select DCACHE_WORD_ACCESS 112 select EDAC_ATOMIC_SCRUB 113 select EDAC_SUPPORT 114 select GENERIC_CLOCKEVENTS 115 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 116 select GENERIC_CLOCKEVENTS_MIN_ADJUST 117 select GENERIC_CMOS_UPDATE 118 select GENERIC_CPU_AUTOPROBE 119 select GENERIC_CPU_VULNERABILITIES 120 select GENERIC_EARLY_IOREMAP 121 select GENERIC_ENTRY 122 select GENERIC_FIND_FIRST_BIT 123 select GENERIC_IOMAP 124 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 125 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 126 select GENERIC_IRQ_MIGRATION if SMP 127 select GENERIC_IRQ_PROBE 128 select GENERIC_IRQ_RESERVATION_MODE 129 select GENERIC_IRQ_SHOW 130 select GENERIC_PENDING_IRQ if SMP 131 select GENERIC_PTDUMP 132 select GENERIC_SMP_IDLE_THREAD 133 select GENERIC_STRNCPY_FROM_USER 134 select GENERIC_STRNLEN_USER 135 select GENERIC_TIME_VSYSCALL 136 select GENERIC_GETTIMEOFDAY 137 select GENERIC_VDSO_TIME_NS 138 select GUP_GET_PTE_LOW_HIGH if X86_PAE 139 select HARDIRQS_SW_RESEND 140 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 141 select HAVE_ACPI_APEI if ACPI 142 select HAVE_ACPI_APEI_NMI if ACPI 143 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 144 select HAVE_ARCH_AUDITSYSCALL 145 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 146 select HAVE_ARCH_JUMP_LABEL 147 select HAVE_ARCH_JUMP_LABEL_RELATIVE 148 select HAVE_ARCH_KASAN if X86_64 149 select HAVE_ARCH_KASAN_VMALLOC if X86_64 150 select HAVE_ARCH_KGDB 151 select HAVE_ARCH_MMAP_RND_BITS if MMU 152 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 153 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 154 select HAVE_ARCH_PREL32_RELOCATIONS 155 select HAVE_ARCH_SECCOMP_FILTER 156 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 157 select HAVE_ARCH_STACKLEAK 158 select HAVE_ARCH_TRACEHOOK 159 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 160 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 161 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 162 select HAVE_ARCH_VMAP_STACK if X86_64 163 select HAVE_ARCH_WITHIN_STACK_FRAMES 164 select HAVE_ASM_MODVERSIONS 165 select HAVE_CMPXCHG_DOUBLE 166 select HAVE_CMPXCHG_LOCAL 167 select HAVE_CONTEXT_TRACKING if X86_64 168 select HAVE_C_RECORDMCOUNT 169 select HAVE_DEBUG_KMEMLEAK 170 select HAVE_DMA_CONTIGUOUS 171 select HAVE_DYNAMIC_FTRACE 172 select HAVE_DYNAMIC_FTRACE_WITH_REGS 173 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 174 select HAVE_EBPF_JIT 175 select HAVE_EFFICIENT_UNALIGNED_ACCESS 176 select HAVE_EISA 177 select HAVE_EXIT_THREAD 178 select HAVE_FAST_GUP 179 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 180 select HAVE_FTRACE_MCOUNT_RECORD 181 select HAVE_FUNCTION_GRAPH_TRACER 182 select HAVE_FUNCTION_TRACER 183 select HAVE_GCC_PLUGINS 184 select HAVE_HW_BREAKPOINT 185 select HAVE_IDE 186 select HAVE_IOREMAP_PROT 187 select HAVE_IRQ_TIME_ACCOUNTING 188 select HAVE_KERNEL_BZIP2 189 select HAVE_KERNEL_GZIP 190 select HAVE_KERNEL_LZ4 191 select HAVE_KERNEL_LZMA 192 select HAVE_KERNEL_LZO 193 select HAVE_KERNEL_XZ 194 select HAVE_KERNEL_ZSTD 195 select HAVE_KPROBES 196 select HAVE_KPROBES_ON_FTRACE 197 select HAVE_FUNCTION_ERROR_INJECTION 198 select HAVE_KRETPROBES 199 select HAVE_KVM 200 select HAVE_LIVEPATCH if X86_64 201 select HAVE_MIXED_BREAKPOINTS_REGS 202 select HAVE_MOD_ARCH_SPECIFIC 203 select HAVE_MOVE_PMD 204 select HAVE_NMI 205 select HAVE_OPROFILE 206 select HAVE_OPTPROBES 207 select HAVE_PCSPKR_PLATFORM 208 select HAVE_PERF_EVENTS 209 select HAVE_PERF_EVENTS_NMI 210 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 211 select HAVE_PCI 212 select HAVE_PERF_REGS 213 select HAVE_PERF_USER_STACK_DUMP 214 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 215 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 216 select HAVE_REGS_AND_STACK_ACCESS_API 217 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 218 select HAVE_FUNCTION_ARG_ACCESS_API 219 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 220 select HAVE_STACK_VALIDATION if X86_64 221 select HAVE_STATIC_CALL 222 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 223 select HAVE_RSEQ 224 select HAVE_SYSCALL_TRACEPOINTS 225 select HAVE_UNSTABLE_SCHED_CLOCK 226 select HAVE_USER_RETURN_NOTIFIER 227 select HAVE_GENERIC_VDSO 228 select HOTPLUG_SMT if SMP 229 select IRQ_FORCED_THREADING 230 select NEED_SG_DMA_LENGTH 231 select PCI_DOMAINS if PCI 232 select PCI_LOCKLESS_CONFIG if PCI 233 select PERF_EVENTS 234 select RTC_LIB 235 select RTC_MC146818_LIB 236 select SPARSE_IRQ 237 select SRCU 238 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 239 select SYSCTL_EXCEPTION_TRACE 240 select THREAD_INFO_IN_TASK 241 select USER_STACKTRACE_SUPPORT 242 select VIRT_TO_BUS 243 select HAVE_ARCH_KCSAN if X86_64 244 select X86_FEATURE_NAMES if PROC_FS 245 select PROC_PID_ARCH_STATUS if PROC_FS 246 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 247 248config INSTRUCTION_DECODER 249 def_bool y 250 depends on KPROBES || PERF_EVENTS || UPROBES 251 252config OUTPUT_FORMAT 253 string 254 default "elf32-i386" if X86_32 255 default "elf64-x86-64" if X86_64 256 257config LOCKDEP_SUPPORT 258 def_bool y 259 260config STACKTRACE_SUPPORT 261 def_bool y 262 263config MMU 264 def_bool y 265 266config ARCH_MMAP_RND_BITS_MIN 267 default 28 if 64BIT 268 default 8 269 270config ARCH_MMAP_RND_BITS_MAX 271 default 32 if 64BIT 272 default 16 273 274config ARCH_MMAP_RND_COMPAT_BITS_MIN 275 default 8 276 277config ARCH_MMAP_RND_COMPAT_BITS_MAX 278 default 16 279 280config SBUS 281 bool 282 283config GENERIC_ISA_DMA 284 def_bool y 285 depends on ISA_DMA_API 286 287config GENERIC_BUG 288 def_bool y 289 depends on BUG 290 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 291 292config GENERIC_BUG_RELATIVE_POINTERS 293 bool 294 295config ARCH_MAY_HAVE_PC_FDC 296 def_bool y 297 depends on ISA_DMA_API 298 299config GENERIC_CALIBRATE_DELAY 300 def_bool y 301 302config ARCH_HAS_CPU_RELAX 303 def_bool y 304 305config ARCH_HAS_CACHE_LINE_SIZE 306 def_bool y 307 308config ARCH_HAS_FILTER_PGPROT 309 def_bool y 310 311config HAVE_SETUP_PER_CPU_AREA 312 def_bool y 313 314config NEED_PER_CPU_EMBED_FIRST_CHUNK 315 def_bool y 316 317config NEED_PER_CPU_PAGE_FIRST_CHUNK 318 def_bool y 319 320config ARCH_HIBERNATION_POSSIBLE 321 def_bool y 322 323config ARCH_SUSPEND_POSSIBLE 324 def_bool y 325 326config ARCH_WANT_GENERAL_HUGETLB 327 def_bool y 328 329config ZONE_DMA32 330 def_bool y if X86_64 331 332config AUDIT_ARCH 333 def_bool y if X86_64 334 335config ARCH_SUPPORTS_DEBUG_PAGEALLOC 336 def_bool y 337 338config KASAN_SHADOW_OFFSET 339 hex 340 depends on KASAN 341 default 0xdffffc0000000000 342 343config HAVE_INTEL_TXT 344 def_bool y 345 depends on INTEL_IOMMU && ACPI 346 347config X86_32_SMP 348 def_bool y 349 depends on X86_32 && SMP 350 351config X86_64_SMP 352 def_bool y 353 depends on X86_64 && SMP 354 355config X86_32_LAZY_GS 356 def_bool y 357 depends on X86_32 && !STACKPROTECTOR 358 359config ARCH_SUPPORTS_UPROBES 360 def_bool y 361 362config FIX_EARLYCON_MEM 363 def_bool y 364 365config DYNAMIC_PHYSICAL_MASK 366 bool 367 368config PGTABLE_LEVELS 369 int 370 default 5 if X86_5LEVEL 371 default 4 if X86_64 372 default 3 if X86_PAE 373 default 2 374 375config CC_HAS_SANE_STACKPROTECTOR 376 bool 377 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 378 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 379 help 380 We have to make sure stack protector is unconditionally disabled if 381 the compiler produces broken code. 382 383menu "Processor type and features" 384 385config ZONE_DMA 386 bool "DMA memory allocation support" if EXPERT 387 default y 388 help 389 DMA memory allocation support allows devices with less than 32-bit 390 addressing to allocate within the first 16MB of address space. 391 Disable if no such devices will be used. 392 393 If unsure, say Y. 394 395config SMP 396 bool "Symmetric multi-processing support" 397 help 398 This enables support for systems with more than one CPU. If you have 399 a system with only one CPU, say N. If you have a system with more 400 than one CPU, say Y. 401 402 If you say N here, the kernel will run on uni- and multiprocessor 403 machines, but will use only one CPU of a multiprocessor machine. If 404 you say Y here, the kernel will run on many, but not all, 405 uniprocessor machines. On a uniprocessor machine, the kernel 406 will run faster if you say N here. 407 408 Note that if you say Y here and choose architecture "586" or 409 "Pentium" under "Processor family", the kernel will not work on 486 410 architectures. Similarly, multiprocessor kernels for the "PPro" 411 architecture may not work on all Pentium based boards. 412 413 People using multiprocessor machines who say Y here should also say 414 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 415 Management" code will be disabled if you say Y here. 416 417 See also <file:Documentation/x86/i386/IO-APIC.rst>, 418 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 419 <http://www.tldp.org/docs.html#howto>. 420 421 If you don't know what to do here, say N. 422 423config X86_FEATURE_NAMES 424 bool "Processor feature human-readable names" if EMBEDDED 425 default y 426 help 427 This option compiles in a table of x86 feature bits and corresponding 428 names. This is required to support /proc/cpuinfo and a few kernel 429 messages. You can disable this to save space, at the expense of 430 making those few kernel messages show numeric feature bits instead. 431 432 If in doubt, say Y. 433 434config X86_X2APIC 435 bool "Support x2apic" 436 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 437 help 438 This enables x2apic support on CPUs that have this feature. 439 440 This allows 32-bit apic IDs (so it can support very large systems), 441 and accesses the local apic via MSRs not via mmio. 442 443 If you don't know what to do here, say N. 444 445config X86_MPPARSE 446 bool "Enable MPS table" if ACPI || SFI 447 default y 448 depends on X86_LOCAL_APIC 449 help 450 For old smp systems that do not have proper acpi support. Newer systems 451 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 452 453config GOLDFISH 454 def_bool y 455 depends on X86_GOLDFISH 456 457config X86_CPU_RESCTRL 458 bool "x86 CPU resource control support" 459 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 460 select KERNFS 461 select PROC_CPU_RESCTRL if PROC_FS 462 help 463 Enable x86 CPU resource control support. 464 465 Provide support for the allocation and monitoring of system resources 466 usage by the CPU. 467 468 Intel calls this Intel Resource Director Technology 469 (Intel(R) RDT). More information about RDT can be found in the 470 Intel x86 Architecture Software Developer Manual. 471 472 AMD calls this AMD Platform Quality of Service (AMD QoS). 473 More information about AMD QoS can be found in the AMD64 Technology 474 Platform Quality of Service Extensions manual. 475 476 Say N if unsure. 477 478if X86_32 479config X86_BIGSMP 480 bool "Support for big SMP systems with more than 8 CPUs" 481 depends on SMP 482 help 483 This option is needed for the systems that have more than 8 CPUs. 484 485config X86_EXTENDED_PLATFORM 486 bool "Support for extended (non-PC) x86 platforms" 487 default y 488 help 489 If you disable this option then the kernel will only support 490 standard PC platforms. (which covers the vast majority of 491 systems out there.) 492 493 If you enable this option then you'll be able to select support 494 for the following (non-PC) 32 bit x86 platforms: 495 Goldfish (Android emulator) 496 AMD Elan 497 RDC R-321x SoC 498 SGI 320/540 (Visual Workstation) 499 STA2X11-based (e.g. Northville) 500 Moorestown MID devices 501 502 If you have one of these systems, or if you want to build a 503 generic distribution kernel, say Y here - otherwise say N. 504endif 505 506if X86_64 507config X86_EXTENDED_PLATFORM 508 bool "Support for extended (non-PC) x86 platforms" 509 default y 510 help 511 If you disable this option then the kernel will only support 512 standard PC platforms. (which covers the vast majority of 513 systems out there.) 514 515 If you enable this option then you'll be able to select support 516 for the following (non-PC) 64 bit x86 platforms: 517 Numascale NumaChip 518 ScaleMP vSMP 519 SGI Ultraviolet 520 521 If you have one of these systems, or if you want to build a 522 generic distribution kernel, say Y here - otherwise say N. 523endif 524# This is an alphabetically sorted list of 64 bit extended platforms 525# Please maintain the alphabetic order if and when there are additions 526config X86_NUMACHIP 527 bool "Numascale NumaChip" 528 depends on X86_64 529 depends on X86_EXTENDED_PLATFORM 530 depends on NUMA 531 depends on SMP 532 depends on X86_X2APIC 533 depends on PCI_MMCONFIG 534 help 535 Adds support for Numascale NumaChip large-SMP systems. Needed to 536 enable more than ~168 cores. 537 If you don't have one of these, you should say N here. 538 539config X86_VSMP 540 bool "ScaleMP vSMP" 541 select HYPERVISOR_GUEST 542 select PARAVIRT 543 depends on X86_64 && PCI 544 depends on X86_EXTENDED_PLATFORM 545 depends on SMP 546 help 547 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 548 supposed to run on these EM64T-based machines. Only choose this option 549 if you have one of these machines. 550 551config X86_UV 552 bool "SGI Ultraviolet" 553 depends on X86_64 554 depends on X86_EXTENDED_PLATFORM 555 depends on NUMA 556 depends on EFI 557 depends on KEXEC_CORE 558 depends on X86_X2APIC 559 depends on PCI 560 help 561 This option is needed in order to support SGI Ultraviolet systems. 562 If you don't have one of these, you should say N here. 563 564# Following is an alphabetically sorted list of 32 bit extended platforms 565# Please maintain the alphabetic order if and when there are additions 566 567config X86_GOLDFISH 568 bool "Goldfish (Virtual Platform)" 569 depends on X86_EXTENDED_PLATFORM 570 help 571 Enable support for the Goldfish virtual platform used primarily 572 for Android development. Unless you are building for the Android 573 Goldfish emulator say N here. 574 575config X86_INTEL_CE 576 bool "CE4100 TV platform" 577 depends on PCI 578 depends on PCI_GODIRECT 579 depends on X86_IO_APIC 580 depends on X86_32 581 depends on X86_EXTENDED_PLATFORM 582 select X86_REBOOTFIXUPS 583 select OF 584 select OF_EARLY_FLATTREE 585 help 586 Select for the Intel CE media processor (CE4100) SOC. 587 This option compiles in support for the CE4100 SOC for settop 588 boxes and media devices. 589 590config X86_INTEL_MID 591 bool "Intel MID platform support" 592 depends on X86_EXTENDED_PLATFORM 593 depends on X86_PLATFORM_DEVICES 594 depends on PCI 595 depends on X86_64 || (PCI_GOANY && X86_32) 596 depends on X86_IO_APIC 597 select SFI 598 select I2C 599 select DW_APB_TIMER 600 select APB_TIMER 601 select INTEL_SCU_PCI 602 select MFD_INTEL_MSIC 603 help 604 Select to build a kernel capable of supporting Intel MID (Mobile 605 Internet Device) platform systems which do not have the PCI legacy 606 interfaces. If you are building for a PC class system say N here. 607 608 Intel MID platforms are based on an Intel processor and chipset which 609 consume less power than most of the x86 derivatives. 610 611config X86_INTEL_QUARK 612 bool "Intel Quark platform support" 613 depends on X86_32 614 depends on X86_EXTENDED_PLATFORM 615 depends on X86_PLATFORM_DEVICES 616 depends on X86_TSC 617 depends on PCI 618 depends on PCI_GOANY 619 depends on X86_IO_APIC 620 select IOSF_MBI 621 select INTEL_IMR 622 select COMMON_CLK 623 help 624 Select to include support for Quark X1000 SoC. 625 Say Y here if you have a Quark based system such as the Arduino 626 compatible Intel Galileo. 627 628config X86_INTEL_LPSS 629 bool "Intel Low Power Subsystem Support" 630 depends on X86 && ACPI && PCI 631 select COMMON_CLK 632 select PINCTRL 633 select IOSF_MBI 634 help 635 Select to build support for Intel Low Power Subsystem such as 636 found on Intel Lynxpoint PCH. Selecting this option enables 637 things like clock tree (common clock framework) and pincontrol 638 which are needed by the LPSS peripheral drivers. 639 640config X86_AMD_PLATFORM_DEVICE 641 bool "AMD ACPI2Platform devices support" 642 depends on ACPI 643 select COMMON_CLK 644 select PINCTRL 645 help 646 Select to interpret AMD specific ACPI device to platform device 647 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 648 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 649 implemented under PINCTRL subsystem. 650 651config IOSF_MBI 652 tristate "Intel SoC IOSF Sideband support for SoC platforms" 653 depends on PCI 654 help 655 This option enables sideband register access support for Intel SoC 656 platforms. On these platforms the IOSF sideband is used in lieu of 657 MSR's for some register accesses, mostly but not limited to thermal 658 and power. Drivers may query the availability of this device to 659 determine if they need the sideband in order to work on these 660 platforms. The sideband is available on the following SoC products. 661 This list is not meant to be exclusive. 662 - BayTrail 663 - Braswell 664 - Quark 665 666 You should say Y if you are running a kernel on one of these SoC's. 667 668config IOSF_MBI_DEBUG 669 bool "Enable IOSF sideband access through debugfs" 670 depends on IOSF_MBI && DEBUG_FS 671 help 672 Select this option to expose the IOSF sideband access registers (MCR, 673 MDR, MCRX) through debugfs to write and read register information from 674 different units on the SoC. This is most useful for obtaining device 675 state information for debug and analysis. As this is a general access 676 mechanism, users of this option would have specific knowledge of the 677 device they want to access. 678 679 If you don't require the option or are in doubt, say N. 680 681config X86_RDC321X 682 bool "RDC R-321x SoC" 683 depends on X86_32 684 depends on X86_EXTENDED_PLATFORM 685 select M486 686 select X86_REBOOTFIXUPS 687 help 688 This option is needed for RDC R-321x system-on-chip, also known 689 as R-8610-(G). 690 If you don't have one of these chips, you should say N here. 691 692config X86_32_NON_STANDARD 693 bool "Support non-standard 32-bit SMP architectures" 694 depends on X86_32 && SMP 695 depends on X86_EXTENDED_PLATFORM 696 help 697 This option compiles in the bigsmp and STA2X11 default 698 subarchitectures. It is intended for a generic binary 699 kernel. If you select them all, kernel will probe it one by 700 one and will fallback to default. 701 702# Alphabetically sorted list of Non standard 32 bit platforms 703 704config X86_SUPPORTS_MEMORY_FAILURE 705 def_bool y 706 # MCE code calls memory_failure(): 707 depends on X86_MCE 708 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 709 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 710 depends on X86_64 || !SPARSEMEM 711 select ARCH_SUPPORTS_MEMORY_FAILURE 712 713config STA2X11 714 bool "STA2X11 Companion Chip Support" 715 depends on X86_32_NON_STANDARD && PCI 716 select SWIOTLB 717 select MFD_STA2X11 718 select GPIOLIB 719 help 720 This adds support for boards based on the STA2X11 IO-Hub, 721 a.k.a. "ConneXt". The chip is used in place of the standard 722 PC chipset, so all "standard" peripherals are missing. If this 723 option is selected the kernel will still be able to boot on 724 standard PC machines. 725 726config X86_32_IRIS 727 tristate "Eurobraille/Iris poweroff module" 728 depends on X86_32 729 help 730 The Iris machines from EuroBraille do not have APM or ACPI support 731 to shut themselves down properly. A special I/O sequence is 732 needed to do so, which is what this module does at 733 kernel shutdown. 734 735 This is only for Iris machines from EuroBraille. 736 737 If unused, say N. 738 739config SCHED_OMIT_FRAME_POINTER 740 def_bool y 741 prompt "Single-depth WCHAN output" 742 depends on X86 743 help 744 Calculate simpler /proc/<PID>/wchan values. If this option 745 is disabled then wchan values will recurse back to the 746 caller function. This provides more accurate wchan values, 747 at the expense of slightly more scheduling overhead. 748 749 If in doubt, say "Y". 750 751menuconfig HYPERVISOR_GUEST 752 bool "Linux guest support" 753 help 754 Say Y here to enable options for running Linux under various hyper- 755 visors. This option enables basic hypervisor detection and platform 756 setup. 757 758 If you say N, all options in this submenu will be skipped and 759 disabled, and Linux guest support won't be built in. 760 761if HYPERVISOR_GUEST 762 763config PARAVIRT 764 bool "Enable paravirtualization code" 765 help 766 This changes the kernel so it can modify itself when it is run 767 under a hypervisor, potentially improving performance significantly 768 over full virtualization. However, when run without a hypervisor 769 the kernel is theoretically slower and slightly larger. 770 771config PARAVIRT_XXL 772 bool 773 774config PARAVIRT_DEBUG 775 bool "paravirt-ops debugging" 776 depends on PARAVIRT && DEBUG_KERNEL 777 help 778 Enable to debug paravirt_ops internals. Specifically, BUG if 779 a paravirt_op is missing when it is called. 780 781config PARAVIRT_SPINLOCKS 782 bool "Paravirtualization layer for spinlocks" 783 depends on PARAVIRT && SMP 784 help 785 Paravirtualized spinlocks allow a pvops backend to replace the 786 spinlock implementation with something virtualization-friendly 787 (for example, block the virtual CPU rather than spinning). 788 789 It has a minimal impact on native kernels and gives a nice performance 790 benefit on paravirtualized KVM / Xen kernels. 791 792 If you are unsure how to answer this question, answer Y. 793 794config X86_HV_CALLBACK_VECTOR 795 def_bool n 796 797source "arch/x86/xen/Kconfig" 798 799config KVM_GUEST 800 bool "KVM Guest support (including kvmclock)" 801 depends on PARAVIRT 802 select PARAVIRT_CLOCK 803 select ARCH_CPUIDLE_HALTPOLL 804 select X86_HV_CALLBACK_VECTOR 805 default y 806 help 807 This option enables various optimizations for running under the KVM 808 hypervisor. It includes a paravirtualized clock, so that instead 809 of relying on a PIT (or probably other) emulation by the 810 underlying device model, the host provides the guest with 811 timing infrastructure such as time of day, and system time 812 813config ARCH_CPUIDLE_HALTPOLL 814 def_bool n 815 prompt "Disable host haltpoll when loading haltpoll driver" 816 help 817 If virtualized under KVM, disable host haltpoll. 818 819config PVH 820 bool "Support for running PVH guests" 821 help 822 This option enables the PVH entry point for guest virtual machines 823 as specified in the x86/HVM direct boot ABI. 824 825config PARAVIRT_TIME_ACCOUNTING 826 bool "Paravirtual steal time accounting" 827 depends on PARAVIRT 828 help 829 Select this option to enable fine granularity task steal time 830 accounting. Time spent executing other tasks in parallel with 831 the current vCPU is discounted from the vCPU power. To account for 832 that, there can be a small performance impact. 833 834 If in doubt, say N here. 835 836config PARAVIRT_CLOCK 837 bool 838 839config JAILHOUSE_GUEST 840 bool "Jailhouse non-root cell support" 841 depends on X86_64 && PCI 842 select X86_PM_TIMER 843 help 844 This option allows to run Linux as guest in a Jailhouse non-root 845 cell. You can leave this option disabled if you only want to start 846 Jailhouse and run Linux afterwards in the root cell. 847 848config ACRN_GUEST 849 bool "ACRN Guest support" 850 depends on X86_64 851 select X86_HV_CALLBACK_VECTOR 852 help 853 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 854 a flexible, lightweight reference open-source hypervisor, built with 855 real-time and safety-criticality in mind. It is built for embedded 856 IOT with small footprint and real-time features. More details can be 857 found in https://projectacrn.org/. 858 859endif #HYPERVISOR_GUEST 860 861source "arch/x86/Kconfig.cpu" 862 863config HPET_TIMER 864 def_bool X86_64 865 prompt "HPET Timer Support" if X86_32 866 help 867 Use the IA-PC HPET (High Precision Event Timer) to manage 868 time in preference to the PIT and RTC, if a HPET is 869 present. 870 HPET is the next generation timer replacing legacy 8254s. 871 The HPET provides a stable time base on SMP 872 systems, unlike the TSC, but it is more expensive to access, 873 as it is off-chip. The interface used is documented 874 in the HPET spec, revision 1. 875 876 You can safely choose Y here. However, HPET will only be 877 activated if the platform and the BIOS support this feature. 878 Otherwise the 8254 will be used for timing services. 879 880 Choose N to continue using the legacy 8254 timer. 881 882config HPET_EMULATE_RTC 883 def_bool y 884 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 885 886config APB_TIMER 887 def_bool y if X86_INTEL_MID 888 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 889 select DW_APB_TIMER 890 depends on X86_INTEL_MID && SFI 891 help 892 APB timer is the replacement for 8254, HPET on X86 MID platforms. 893 The APBT provides a stable time base on SMP 894 systems, unlike the TSC, but it is more expensive to access, 895 as it is off-chip. APB timers are always running regardless of CPU 896 C states, they are used as per CPU clockevent device when possible. 897 898# Mark as expert because too many people got it wrong. 899# The code disables itself when not needed. 900config DMI 901 default y 902 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 903 bool "Enable DMI scanning" if EXPERT 904 help 905 Enabled scanning of DMI to identify machine quirks. Say Y 906 here unless you have verified that your setup is not 907 affected by entries in the DMI blacklist. Required by PNP 908 BIOS code. 909 910config GART_IOMMU 911 bool "Old AMD GART IOMMU support" 912 select DMA_OPS 913 select IOMMU_HELPER 914 select SWIOTLB 915 depends on X86_64 && PCI && AMD_NB 916 help 917 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 918 GART based hardware IOMMUs. 919 920 The GART supports full DMA access for devices with 32-bit access 921 limitations, on systems with more than 3 GB. This is usually needed 922 for USB, sound, many IDE/SATA chipsets and some other devices. 923 924 Newer systems typically have a modern AMD IOMMU, supported via 925 the CONFIG_AMD_IOMMU=y config option. 926 927 In normal configurations this driver is only active when needed: 928 there's more than 3 GB of memory and the system contains a 929 32-bit limited device. 930 931 If unsure, say Y. 932 933config MAXSMP 934 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 935 depends on X86_64 && SMP && DEBUG_KERNEL 936 select CPUMASK_OFFSTACK 937 help 938 Enable maximum number of CPUS and NUMA Nodes for this architecture. 939 If unsure, say N. 940 941# 942# The maximum number of CPUs supported: 943# 944# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 945# and which can be configured interactively in the 946# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 947# 948# The ranges are different on 32-bit and 64-bit kernels, depending on 949# hardware capabilities and scalability features of the kernel. 950# 951# ( If MAXSMP is enabled we just use the highest possible value and disable 952# interactive configuration. ) 953# 954 955config NR_CPUS_RANGE_BEGIN 956 int 957 default NR_CPUS_RANGE_END if MAXSMP 958 default 1 if !SMP 959 default 2 960 961config NR_CPUS_RANGE_END 962 int 963 depends on X86_32 964 default 64 if SMP && X86_BIGSMP 965 default 8 if SMP && !X86_BIGSMP 966 default 1 if !SMP 967 968config NR_CPUS_RANGE_END 969 int 970 depends on X86_64 971 default 8192 if SMP && CPUMASK_OFFSTACK 972 default 512 if SMP && !CPUMASK_OFFSTACK 973 default 1 if !SMP 974 975config NR_CPUS_DEFAULT 976 int 977 depends on X86_32 978 default 32 if X86_BIGSMP 979 default 8 if SMP 980 default 1 if !SMP 981 982config NR_CPUS_DEFAULT 983 int 984 depends on X86_64 985 default 8192 if MAXSMP 986 default 64 if SMP 987 default 1 if !SMP 988 989config NR_CPUS 990 int "Maximum number of CPUs" if SMP && !MAXSMP 991 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 992 default NR_CPUS_DEFAULT 993 help 994 This allows you to specify the maximum number of CPUs which this 995 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 996 supported value is 8192, otherwise the maximum value is 512. The 997 minimum value which makes sense is 2. 998 999 This is purely to save memory: each supported CPU adds about 8KB 1000 to the kernel image. 1001 1002config SCHED_SMT 1003 def_bool y if SMP 1004 1005config SCHED_MC 1006 def_bool y 1007 prompt "Multi-core scheduler support" 1008 depends on SMP 1009 help 1010 Multi-core scheduler support improves the CPU scheduler's decision 1011 making when dealing with multi-core CPU chips at a cost of slightly 1012 increased overhead in some places. If unsure say N here. 1013 1014config SCHED_MC_PRIO 1015 bool "CPU core priorities scheduler support" 1016 depends on SCHED_MC && CPU_SUP_INTEL 1017 select X86_INTEL_PSTATE 1018 select CPU_FREQ 1019 default y 1020 help 1021 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1022 core ordering determined at manufacturing time, which allows 1023 certain cores to reach higher turbo frequencies (when running 1024 single threaded workloads) than others. 1025 1026 Enabling this kernel feature teaches the scheduler about 1027 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1028 scheduler's CPU selection logic accordingly, so that higher 1029 overall system performance can be achieved. 1030 1031 This feature will have no effect on CPUs without this feature. 1032 1033 If unsure say Y here. 1034 1035config UP_LATE_INIT 1036 def_bool y 1037 depends on !SMP && X86_LOCAL_APIC 1038 1039config X86_UP_APIC 1040 bool "Local APIC support on uniprocessors" if !PCI_MSI 1041 default PCI_MSI 1042 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1043 help 1044 A local APIC (Advanced Programmable Interrupt Controller) is an 1045 integrated interrupt controller in the CPU. If you have a single-CPU 1046 system which has a processor with a local APIC, you can say Y here to 1047 enable and use it. If you say Y here even though your machine doesn't 1048 have a local APIC, then the kernel will still run with no slowdown at 1049 all. The local APIC supports CPU-generated self-interrupts (timer, 1050 performance counters), and the NMI watchdog which detects hard 1051 lockups. 1052 1053config X86_UP_IOAPIC 1054 bool "IO-APIC support on uniprocessors" 1055 depends on X86_UP_APIC 1056 help 1057 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1058 SMP-capable replacement for PC-style interrupt controllers. Most 1059 SMP systems and many recent uniprocessor systems have one. 1060 1061 If you have a single-CPU system with an IO-APIC, you can say Y here 1062 to use it. If you say Y here even though your machine doesn't have 1063 an IO-APIC, then the kernel will still run with no slowdown at all. 1064 1065config X86_LOCAL_APIC 1066 def_bool y 1067 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1068 select IRQ_DOMAIN_HIERARCHY 1069 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1070 1071config X86_IO_APIC 1072 def_bool y 1073 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1074 1075config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1076 bool "Reroute for broken boot IRQs" 1077 depends on X86_IO_APIC 1078 help 1079 This option enables a workaround that fixes a source of 1080 spurious interrupts. This is recommended when threaded 1081 interrupt handling is used on systems where the generation of 1082 superfluous "boot interrupts" cannot be disabled. 1083 1084 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1085 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1086 kernel does during interrupt handling). On chipsets where this 1087 boot IRQ generation cannot be disabled, this workaround keeps 1088 the original IRQ line masked so that only the equivalent "boot 1089 IRQ" is delivered to the CPUs. The workaround also tells the 1090 kernel to set up the IRQ handler on the boot IRQ line. In this 1091 way only one interrupt is delivered to the kernel. Otherwise 1092 the spurious second interrupt may cause the kernel to bring 1093 down (vital) interrupt lines. 1094 1095 Only affects "broken" chipsets. Interrupt sharing may be 1096 increased on these systems. 1097 1098config X86_MCE 1099 bool "Machine Check / overheating reporting" 1100 select GENERIC_ALLOCATOR 1101 default y 1102 help 1103 Machine Check support allows the processor to notify the 1104 kernel if it detects a problem (e.g. overheating, data corruption). 1105 The action the kernel takes depends on the severity of the problem, 1106 ranging from warning messages to halting the machine. 1107 1108config X86_MCELOG_LEGACY 1109 bool "Support for deprecated /dev/mcelog character device" 1110 depends on X86_MCE 1111 help 1112 Enable support for /dev/mcelog which is needed by the old mcelog 1113 userspace logging daemon. Consider switching to the new generation 1114 rasdaemon solution. 1115 1116config X86_MCE_INTEL 1117 def_bool y 1118 prompt "Intel MCE features" 1119 depends on X86_MCE && X86_LOCAL_APIC 1120 help 1121 Additional support for intel specific MCE features such as 1122 the thermal monitor. 1123 1124config X86_MCE_AMD 1125 def_bool y 1126 prompt "AMD MCE features" 1127 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1128 help 1129 Additional support for AMD specific MCE features such as 1130 the DRAM Error Threshold. 1131 1132config X86_ANCIENT_MCE 1133 bool "Support for old Pentium 5 / WinChip machine checks" 1134 depends on X86_32 && X86_MCE 1135 help 1136 Include support for machine check handling on old Pentium 5 or WinChip 1137 systems. These typically need to be enabled explicitly on the command 1138 line. 1139 1140config X86_MCE_THRESHOLD 1141 depends on X86_MCE_AMD || X86_MCE_INTEL 1142 def_bool y 1143 1144config X86_MCE_INJECT 1145 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1146 tristate "Machine check injector support" 1147 help 1148 Provide support for injecting machine checks for testing purposes. 1149 If you don't know what a machine check is and you don't do kernel 1150 QA it is safe to say n. 1151 1152config X86_THERMAL_VECTOR 1153 def_bool y 1154 depends on X86_MCE_INTEL 1155 1156source "arch/x86/events/Kconfig" 1157 1158config X86_LEGACY_VM86 1159 bool "Legacy VM86 support" 1160 depends on X86_32 1161 help 1162 This option allows user programs to put the CPU into V8086 1163 mode, which is an 80286-era approximation of 16-bit real mode. 1164 1165 Some very old versions of X and/or vbetool require this option 1166 for user mode setting. Similarly, DOSEMU will use it if 1167 available to accelerate real mode DOS programs. However, any 1168 recent version of DOSEMU, X, or vbetool should be fully 1169 functional even without kernel VM86 support, as they will all 1170 fall back to software emulation. Nevertheless, if you are using 1171 a 16-bit DOS program where 16-bit performance matters, vm86 1172 mode might be faster than emulation and you might want to 1173 enable this option. 1174 1175 Note that any app that works on a 64-bit kernel is unlikely to 1176 need this option, as 64-bit kernels don't, and can't, support 1177 V8086 mode. This option is also unrelated to 16-bit protected 1178 mode and is not needed to run most 16-bit programs under Wine. 1179 1180 Enabling this option increases the complexity of the kernel 1181 and slows down exception handling a tiny bit. 1182 1183 If unsure, say N here. 1184 1185config VM86 1186 bool 1187 default X86_LEGACY_VM86 1188 1189config X86_16BIT 1190 bool "Enable support for 16-bit segments" if EXPERT 1191 default y 1192 depends on MODIFY_LDT_SYSCALL 1193 help 1194 This option is required by programs like Wine to run 16-bit 1195 protected mode legacy code on x86 processors. Disabling 1196 this option saves about 300 bytes on i386, or around 6K text 1197 plus 16K runtime memory on x86-64, 1198 1199config X86_ESPFIX32 1200 def_bool y 1201 depends on X86_16BIT && X86_32 1202 1203config X86_ESPFIX64 1204 def_bool y 1205 depends on X86_16BIT && X86_64 1206 1207config X86_VSYSCALL_EMULATION 1208 bool "Enable vsyscall emulation" if EXPERT 1209 default y 1210 depends on X86_64 1211 help 1212 This enables emulation of the legacy vsyscall page. Disabling 1213 it is roughly equivalent to booting with vsyscall=none, except 1214 that it will also disable the helpful warning if a program 1215 tries to use a vsyscall. With this option set to N, offending 1216 programs will just segfault, citing addresses of the form 1217 0xffffffffff600?00. 1218 1219 This option is required by many programs built before 2013, and 1220 care should be used even with newer programs if set to N. 1221 1222 Disabling this option saves about 7K of kernel size and 1223 possibly 4K of additional runtime pagetable memory. 1224 1225config X86_IOPL_IOPERM 1226 bool "IOPERM and IOPL Emulation" 1227 default y 1228 help 1229 This enables the ioperm() and iopl() syscalls which are necessary 1230 for legacy applications. 1231 1232 Legacy IOPL support is an overbroad mechanism which allows user 1233 space aside of accessing all 65536 I/O ports also to disable 1234 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1235 capabilities and permission from potentially active security 1236 modules. 1237 1238 The emulation restricts the functionality of the syscall to 1239 only allowing the full range I/O port access, but prevents the 1240 ability to disable interrupts from user space which would be 1241 granted if the hardware IOPL mechanism would be used. 1242 1243config TOSHIBA 1244 tristate "Toshiba Laptop support" 1245 depends on X86_32 1246 help 1247 This adds a driver to safely access the System Management Mode of 1248 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1249 not work on models with a Phoenix BIOS. The System Management Mode 1250 is used to set the BIOS and power saving options on Toshiba portables. 1251 1252 For information on utilities to make use of this driver see the 1253 Toshiba Linux utilities web site at: 1254 <http://www.buzzard.org.uk/toshiba/>. 1255 1256 Say Y if you intend to run this kernel on a Toshiba portable. 1257 Say N otherwise. 1258 1259config I8K 1260 tristate "Dell i8k legacy laptop support" 1261 depends on HWMON 1262 depends on PROC_FS 1263 select SENSORS_DELL_SMM 1264 help 1265 This option enables legacy /proc/i8k userspace interface in hwmon 1266 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1267 temperature and allows controlling fan speeds of Dell laptops via 1268 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1269 it reports also power and hotkey status. For fan speed control is 1270 needed userspace package i8kutils. 1271 1272 Say Y if you intend to run this kernel on old Dell laptops or want to 1273 use userspace package i8kutils. 1274 Say N otherwise. 1275 1276config X86_REBOOTFIXUPS 1277 bool "Enable X86 board specific fixups for reboot" 1278 depends on X86_32 1279 help 1280 This enables chipset and/or board specific fixups to be done 1281 in order to get reboot to work correctly. This is only needed on 1282 some combinations of hardware and BIOS. The symptom, for which 1283 this config is intended, is when reboot ends with a stalled/hung 1284 system. 1285 1286 Currently, the only fixup is for the Geode machines using 1287 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1288 1289 Say Y if you want to enable the fixup. Currently, it's safe to 1290 enable this option even if you don't need it. 1291 Say N otherwise. 1292 1293config MICROCODE 1294 bool "CPU microcode loading support" 1295 default y 1296 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1297 help 1298 If you say Y here, you will be able to update the microcode on 1299 Intel and AMD processors. The Intel support is for the IA32 family, 1300 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1301 AMD support is for families 0x10 and later. You will obviously need 1302 the actual microcode binary data itself which is not shipped with 1303 the Linux kernel. 1304 1305 The preferred method to load microcode from a detached initrd is described 1306 in Documentation/x86/microcode.rst. For that you need to enable 1307 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1308 initrd for microcode blobs. 1309 1310 In addition, you can build the microcode into the kernel. For that you 1311 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1312 config option. 1313 1314config MICROCODE_INTEL 1315 bool "Intel microcode loading support" 1316 depends on CPU_SUP_INTEL && MICROCODE 1317 default MICROCODE 1318 help 1319 This options enables microcode patch loading support for Intel 1320 processors. 1321 1322 For the current Intel microcode data package go to 1323 <https://downloadcenter.intel.com> and search for 1324 'Linux Processor Microcode Data File'. 1325 1326config MICROCODE_AMD 1327 bool "AMD microcode loading support" 1328 depends on CPU_SUP_AMD && MICROCODE 1329 help 1330 If you select this option, microcode patch loading support for AMD 1331 processors will be enabled. 1332 1333config MICROCODE_LATE_LOADING 1334 bool "Late microcode loading (DANGEROUS)" 1335 default n 1336 depends on MICROCODE 1337 help 1338 Loading microcode late, when the system is up and executing instructions 1339 is a tricky business and should be avoided if possible. Just the sequence 1340 of synchronizing all cores and SMT threads is one fragile dance which does 1341 not guarantee that cores might not softlock after the loading. Therefore, 1342 use this at your own risk. Late loading taints the kernel too. 1343 1344config X86_MSR 1345 tristate "/dev/cpu/*/msr - Model-specific register support" 1346 help 1347 This device gives privileged processes access to the x86 1348 Model-Specific Registers (MSRs). It is a character device with 1349 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1350 MSR accesses are directed to a specific CPU on multi-processor 1351 systems. 1352 1353config X86_CPUID 1354 tristate "/dev/cpu/*/cpuid - CPU information support" 1355 help 1356 This device gives processes access to the x86 CPUID instruction to 1357 be executed on a specific processor. It is a character device 1358 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1359 /dev/cpu/31/cpuid. 1360 1361choice 1362 prompt "High Memory Support" 1363 default HIGHMEM4G 1364 depends on X86_32 1365 1366config NOHIGHMEM 1367 bool "off" 1368 help 1369 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1370 However, the address space of 32-bit x86 processors is only 4 1371 Gigabytes large. That means that, if you have a large amount of 1372 physical memory, not all of it can be "permanently mapped" by the 1373 kernel. The physical memory that's not permanently mapped is called 1374 "high memory". 1375 1376 If you are compiling a kernel which will never run on a machine with 1377 more than 1 Gigabyte total physical RAM, answer "off" here (default 1378 choice and suitable for most users). This will result in a "3GB/1GB" 1379 split: 3GB are mapped so that each process sees a 3GB virtual memory 1380 space and the remaining part of the 4GB virtual memory space is used 1381 by the kernel to permanently map as much physical memory as 1382 possible. 1383 1384 If the machine has between 1 and 4 Gigabytes physical RAM, then 1385 answer "4GB" here. 1386 1387 If more than 4 Gigabytes is used then answer "64GB" here. This 1388 selection turns Intel PAE (Physical Address Extension) mode on. 1389 PAE implements 3-level paging on IA32 processors. PAE is fully 1390 supported by Linux, PAE mode is implemented on all recent Intel 1391 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1392 then the kernel will not boot on CPUs that don't support PAE! 1393 1394 The actual amount of total physical memory will either be 1395 auto detected or can be forced by using a kernel command line option 1396 such as "mem=256M". (Try "man bootparam" or see the documentation of 1397 your boot loader (lilo or loadlin) about how to pass options to the 1398 kernel at boot time.) 1399 1400 If unsure, say "off". 1401 1402config HIGHMEM4G 1403 bool "4GB" 1404 help 1405 Select this if you have a 32-bit processor and between 1 and 4 1406 gigabytes of physical RAM. 1407 1408config HIGHMEM64G 1409 bool "64GB" 1410 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1411 select X86_PAE 1412 help 1413 Select this if you have a 32-bit processor and more than 4 1414 gigabytes of physical RAM. 1415 1416endchoice 1417 1418choice 1419 prompt "Memory split" if EXPERT 1420 default VMSPLIT_3G 1421 depends on X86_32 1422 help 1423 Select the desired split between kernel and user memory. 1424 1425 If the address range available to the kernel is less than the 1426 physical memory installed, the remaining memory will be available 1427 as "high memory". Accessing high memory is a little more costly 1428 than low memory, as it needs to be mapped into the kernel first. 1429 Note that increasing the kernel address space limits the range 1430 available to user programs, making the address space there 1431 tighter. Selecting anything other than the default 3G/1G split 1432 will also likely make your kernel incompatible with binary-only 1433 kernel modules. 1434 1435 If you are not absolutely sure what you are doing, leave this 1436 option alone! 1437 1438 config VMSPLIT_3G 1439 bool "3G/1G user/kernel split" 1440 config VMSPLIT_3G_OPT 1441 depends on !X86_PAE 1442 bool "3G/1G user/kernel split (for full 1G low memory)" 1443 config VMSPLIT_2G 1444 bool "2G/2G user/kernel split" 1445 config VMSPLIT_2G_OPT 1446 depends on !X86_PAE 1447 bool "2G/2G user/kernel split (for full 2G low memory)" 1448 config VMSPLIT_1G 1449 bool "1G/3G user/kernel split" 1450endchoice 1451 1452config PAGE_OFFSET 1453 hex 1454 default 0xB0000000 if VMSPLIT_3G_OPT 1455 default 0x80000000 if VMSPLIT_2G 1456 default 0x78000000 if VMSPLIT_2G_OPT 1457 default 0x40000000 if VMSPLIT_1G 1458 default 0xC0000000 1459 depends on X86_32 1460 1461config HIGHMEM 1462 def_bool y 1463 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1464 1465config X86_PAE 1466 bool "PAE (Physical Address Extension) Support" 1467 depends on X86_32 && !HIGHMEM4G 1468 select PHYS_ADDR_T_64BIT 1469 select SWIOTLB 1470 help 1471 PAE is required for NX support, and furthermore enables 1472 larger swapspace support for non-overcommit purposes. It 1473 has the cost of more pagetable lookup overhead, and also 1474 consumes more pagetable space per process. 1475 1476config X86_5LEVEL 1477 bool "Enable 5-level page tables support" 1478 default y 1479 select DYNAMIC_MEMORY_LAYOUT 1480 select SPARSEMEM_VMEMMAP 1481 depends on X86_64 1482 help 1483 5-level paging enables access to larger address space: 1484 upto 128 PiB of virtual address space and 4 PiB of 1485 physical address space. 1486 1487 It will be supported by future Intel CPUs. 1488 1489 A kernel with the option enabled can be booted on machines that 1490 support 4- or 5-level paging. 1491 1492 See Documentation/x86/x86_64/5level-paging.rst for more 1493 information. 1494 1495 Say N if unsure. 1496 1497config X86_DIRECT_GBPAGES 1498 def_bool y 1499 depends on X86_64 1500 help 1501 Certain kernel features effectively disable kernel 1502 linear 1 GB mappings (even if the CPU otherwise 1503 supports them), so don't confuse the user by printing 1504 that we have them enabled. 1505 1506config X86_CPA_STATISTICS 1507 bool "Enable statistic for Change Page Attribute" 1508 depends on DEBUG_FS 1509 help 1510 Expose statistics about the Change Page Attribute mechanism, which 1511 helps to determine the effectiveness of preserving large and huge 1512 page mappings when mapping protections are changed. 1513 1514config AMD_MEM_ENCRYPT 1515 bool "AMD Secure Memory Encryption (SME) support" 1516 depends on X86_64 && CPU_SUP_AMD 1517 select DMA_COHERENT_POOL 1518 select DYNAMIC_PHYSICAL_MASK 1519 select ARCH_USE_MEMREMAP_PROT 1520 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1521 select INSTRUCTION_DECODER 1522 select ARCH_HAS_CC_PLATFORM 1523 help 1524 Say yes to enable support for the encryption of system memory. 1525 This requires an AMD processor that supports Secure Memory 1526 Encryption (SME). 1527 1528config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1529 bool "Activate AMD Secure Memory Encryption (SME) by default" 1530 depends on AMD_MEM_ENCRYPT 1531 help 1532 Say yes to have system memory encrypted by default if running on 1533 an AMD processor that supports Secure Memory Encryption (SME). 1534 1535 If set to Y, then the encryption of system memory can be 1536 deactivated with the mem_encrypt=off command line option. 1537 1538 If set to N, then the encryption of system memory can be 1539 activated with the mem_encrypt=on command line option. 1540 1541# Common NUMA Features 1542config NUMA 1543 bool "NUMA Memory Allocation and Scheduler Support" 1544 depends on SMP 1545 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1546 default y if X86_BIGSMP 1547 help 1548 Enable NUMA (Non-Uniform Memory Access) support. 1549 1550 The kernel will try to allocate memory used by a CPU on the 1551 local memory controller of the CPU and add some more 1552 NUMA awareness to the kernel. 1553 1554 For 64-bit this is recommended if the system is Intel Core i7 1555 (or later), AMD Opteron, or EM64T NUMA. 1556 1557 For 32-bit this is only needed if you boot a 32-bit 1558 kernel on a 64-bit NUMA platform. 1559 1560 Otherwise, you should say N. 1561 1562config AMD_NUMA 1563 def_bool y 1564 prompt "Old style AMD Opteron NUMA detection" 1565 depends on X86_64 && NUMA && PCI 1566 help 1567 Enable AMD NUMA node topology detection. You should say Y here if 1568 you have a multi processor AMD system. This uses an old method to 1569 read the NUMA configuration directly from the builtin Northbridge 1570 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1571 which also takes priority if both are compiled in. 1572 1573config X86_64_ACPI_NUMA 1574 def_bool y 1575 prompt "ACPI NUMA detection" 1576 depends on X86_64 && NUMA && ACPI && PCI 1577 select ACPI_NUMA 1578 help 1579 Enable ACPI SRAT based node topology detection. 1580 1581config NUMA_EMU 1582 bool "NUMA emulation" 1583 depends on NUMA 1584 help 1585 Enable NUMA emulation. A flat machine will be split 1586 into virtual nodes when booted with "numa=fake=N", where N is the 1587 number of nodes. This is only useful for debugging. 1588 1589config NODES_SHIFT 1590 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1591 range 1 10 1592 default "10" if MAXSMP 1593 default "6" if X86_64 1594 default "3" 1595 depends on NEED_MULTIPLE_NODES 1596 help 1597 Specify the maximum number of NUMA Nodes available on the target 1598 system. Increases memory reserved to accommodate various tables. 1599 1600config ARCH_FLATMEM_ENABLE 1601 def_bool y 1602 depends on X86_32 && !NUMA 1603 1604config ARCH_SPARSEMEM_ENABLE 1605 def_bool y 1606 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1607 select SPARSEMEM_STATIC if X86_32 1608 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1609 1610config ARCH_SPARSEMEM_DEFAULT 1611 def_bool X86_64 || (NUMA && X86_32) 1612 1613config ARCH_SELECT_MEMORY_MODEL 1614 def_bool y 1615 depends on ARCH_SPARSEMEM_ENABLE 1616 1617config ARCH_MEMORY_PROBE 1618 bool "Enable sysfs memory/probe interface" 1619 depends on X86_64 && MEMORY_HOTPLUG 1620 help 1621 This option enables a sysfs memory/probe interface for testing. 1622 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1623 If you are unsure how to answer this question, answer N. 1624 1625config ARCH_PROC_KCORE_TEXT 1626 def_bool y 1627 depends on X86_64 && PROC_KCORE 1628 1629config ILLEGAL_POINTER_VALUE 1630 hex 1631 default 0 if X86_32 1632 default 0xdead000000000000 if X86_64 1633 1634config X86_PMEM_LEGACY_DEVICE 1635 bool 1636 1637config X86_PMEM_LEGACY 1638 tristate "Support non-standard NVDIMMs and ADR protected memory" 1639 depends on PHYS_ADDR_T_64BIT 1640 depends on BLK_DEV 1641 select X86_PMEM_LEGACY_DEVICE 1642 select NUMA_KEEP_MEMINFO if NUMA 1643 select LIBNVDIMM 1644 help 1645 Treat memory marked using the non-standard e820 type of 12 as used 1646 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1647 The kernel will offer these regions to the 'pmem' driver so 1648 they can be used for persistent storage. 1649 1650 Say Y if unsure. 1651 1652config HIGHPTE 1653 bool "Allocate 3rd-level pagetables from highmem" 1654 depends on HIGHMEM 1655 help 1656 The VM uses one page table entry for each page of physical memory. 1657 For systems with a lot of RAM, this can be wasteful of precious 1658 low memory. Setting this option will put user-space page table 1659 entries in high memory. 1660 1661config X86_CHECK_BIOS_CORRUPTION 1662 bool "Check for low memory corruption" 1663 help 1664 Periodically check for memory corruption in low memory, which 1665 is suspected to be caused by BIOS. Even when enabled in the 1666 configuration, it is disabled at runtime. Enable it by 1667 setting "memory_corruption_check=1" on the kernel command 1668 line. By default it scans the low 64k of memory every 60 1669 seconds; see the memory_corruption_check_size and 1670 memory_corruption_check_period parameters in 1671 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1672 1673 When enabled with the default parameters, this option has 1674 almost no overhead, as it reserves a relatively small amount 1675 of memory and scans it infrequently. It both detects corruption 1676 and prevents it from affecting the running system. 1677 1678 It is, however, intended as a diagnostic tool; if repeatable 1679 BIOS-originated corruption always affects the same memory, 1680 you can use memmap= to prevent the kernel from using that 1681 memory. 1682 1683config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1684 bool "Set the default setting of memory_corruption_check" 1685 depends on X86_CHECK_BIOS_CORRUPTION 1686 default y 1687 help 1688 Set whether the default state of memory_corruption_check is 1689 on or off. 1690 1691config X86_RESERVE_LOW 1692 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1693 default 64 1694 range 4 640 1695 help 1696 Specify the amount of low memory to reserve for the BIOS. 1697 1698 The first page contains BIOS data structures that the kernel 1699 must not use, so that page must always be reserved. 1700 1701 By default we reserve the first 64K of physical RAM, as a 1702 number of BIOSes are known to corrupt that memory range 1703 during events such as suspend/resume or monitor cable 1704 insertion, so it must not be used by the kernel. 1705 1706 You can set this to 4 if you are absolutely sure that you 1707 trust the BIOS to get all its memory reservations and usages 1708 right. If you know your BIOS have problems beyond the 1709 default 64K area, you can set this to 640 to avoid using the 1710 entire low memory range. 1711 1712 If you have doubts about the BIOS (e.g. suspend/resume does 1713 not work or there's kernel crashes after certain hardware 1714 hotplug events) then you might want to enable 1715 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1716 typical corruption patterns. 1717 1718 Leave this to the default value of 64 if you are unsure. 1719 1720config MATH_EMULATION 1721 bool 1722 depends on MODIFY_LDT_SYSCALL 1723 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1724 help 1725 Linux can emulate a math coprocessor (used for floating point 1726 operations) if you don't have one. 486DX and Pentium processors have 1727 a math coprocessor built in, 486SX and 386 do not, unless you added 1728 a 487DX or 387, respectively. (The messages during boot time can 1729 give you some hints here ["man dmesg"].) Everyone needs either a 1730 coprocessor or this emulation. 1731 1732 If you don't have a math coprocessor, you need to say Y here; if you 1733 say Y here even though you have a coprocessor, the coprocessor will 1734 be used nevertheless. (This behavior can be changed with the kernel 1735 command line option "no387", which comes handy if your coprocessor 1736 is broken. Try "man bootparam" or see the documentation of your boot 1737 loader (lilo or loadlin) about how to pass options to the kernel at 1738 boot time.) This means that it is a good idea to say Y here if you 1739 intend to use this kernel on different machines. 1740 1741 More information about the internals of the Linux math coprocessor 1742 emulation can be found in <file:arch/x86/math-emu/README>. 1743 1744 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1745 kernel, it won't hurt. 1746 1747config MTRR 1748 def_bool y 1749 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1750 help 1751 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1752 the Memory Type Range Registers (MTRRs) may be used to control 1753 processor access to memory ranges. This is most useful if you have 1754 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1755 allows bus write transfers to be combined into a larger transfer 1756 before bursting over the PCI/AGP bus. This can increase performance 1757 of image write operations 2.5 times or more. Saying Y here creates a 1758 /proc/mtrr file which may be used to manipulate your processor's 1759 MTRRs. Typically the X server should use this. 1760 1761 This code has a reasonably generic interface so that similar 1762 control registers on other processors can be easily supported 1763 as well: 1764 1765 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1766 Registers (ARRs) which provide a similar functionality to MTRRs. For 1767 these, the ARRs are used to emulate the MTRRs. 1768 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1769 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1770 write-combining. All of these processors are supported by this code 1771 and it makes sense to say Y here if you have one of them. 1772 1773 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1774 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1775 can lead to all sorts of problems, so it's good to say Y here. 1776 1777 You can safely say Y even if your machine doesn't have MTRRs, you'll 1778 just add about 9 KB to your kernel. 1779 1780 See <file:Documentation/x86/mtrr.rst> for more information. 1781 1782config MTRR_SANITIZER 1783 def_bool y 1784 prompt "MTRR cleanup support" 1785 depends on MTRR 1786 help 1787 Convert MTRR layout from continuous to discrete, so X drivers can 1788 add writeback entries. 1789 1790 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1791 The largest mtrr entry size for a continuous block can be set with 1792 mtrr_chunk_size. 1793 1794 If unsure, say Y. 1795 1796config MTRR_SANITIZER_ENABLE_DEFAULT 1797 int "MTRR cleanup enable value (0-1)" 1798 range 0 1 1799 default "0" 1800 depends on MTRR_SANITIZER 1801 help 1802 Enable mtrr cleanup default value 1803 1804config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1805 int "MTRR cleanup spare reg num (0-7)" 1806 range 0 7 1807 default "1" 1808 depends on MTRR_SANITIZER 1809 help 1810 mtrr cleanup spare entries default, it can be changed via 1811 mtrr_spare_reg_nr=N on the kernel command line. 1812 1813config X86_PAT 1814 def_bool y 1815 prompt "x86 PAT support" if EXPERT 1816 depends on MTRR 1817 help 1818 Use PAT attributes to setup page level cache control. 1819 1820 PATs are the modern equivalents of MTRRs and are much more 1821 flexible than MTRRs. 1822 1823 Say N here if you see bootup problems (boot crash, boot hang, 1824 spontaneous reboots) or a non-working video driver. 1825 1826 If unsure, say Y. 1827 1828config ARCH_USES_PG_UNCACHED 1829 def_bool y 1830 depends on X86_PAT 1831 1832config ARCH_RANDOM 1833 def_bool y 1834 prompt "x86 architectural random number generator" if EXPERT 1835 help 1836 Enable the x86 architectural RDRAND instruction 1837 (Intel Bull Mountain technology) to generate random numbers. 1838 If supported, this is a high bandwidth, cryptographically 1839 secure hardware random number generator. 1840 1841config X86_SMAP 1842 def_bool y 1843 prompt "Supervisor Mode Access Prevention" if EXPERT 1844 help 1845 Supervisor Mode Access Prevention (SMAP) is a security 1846 feature in newer Intel processors. There is a small 1847 performance cost if this enabled and turned on; there is 1848 also a small increase in the kernel size if this is enabled. 1849 1850 If unsure, say Y. 1851 1852config X86_UMIP 1853 def_bool y 1854 prompt "User Mode Instruction Prevention" if EXPERT 1855 help 1856 User Mode Instruction Prevention (UMIP) is a security feature in 1857 some x86 processors. If enabled, a general protection fault is 1858 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1859 executed in user mode. These instructions unnecessarily expose 1860 information about the hardware state. 1861 1862 The vast majority of applications do not use these instructions. 1863 For the very few that do, software emulation is provided in 1864 specific cases in protected and virtual-8086 modes. Emulated 1865 results are dummy. 1866 1867config X86_INTEL_MEMORY_PROTECTION_KEYS 1868 prompt "Memory Protection Keys" 1869 def_bool y 1870 # Note: only available in 64-bit mode 1871 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1872 select ARCH_USES_HIGH_VMA_FLAGS 1873 select ARCH_HAS_PKEYS 1874 help 1875 Memory Protection Keys provides a mechanism for enforcing 1876 page-based protections, but without requiring modification of the 1877 page tables when an application changes protection domains. 1878 1879 For details, see Documentation/core-api/protection-keys.rst 1880 1881 If unsure, say y. 1882 1883choice 1884 prompt "TSX enable mode" 1885 depends on CPU_SUP_INTEL 1886 default X86_INTEL_TSX_MODE_OFF 1887 help 1888 Intel's TSX (Transactional Synchronization Extensions) feature 1889 allows to optimize locking protocols through lock elision which 1890 can lead to a noticeable performance boost. 1891 1892 On the other hand it has been shown that TSX can be exploited 1893 to form side channel attacks (e.g. TAA) and chances are there 1894 will be more of those attacks discovered in the future. 1895 1896 Therefore TSX is not enabled by default (aka tsx=off). An admin 1897 might override this decision by tsx=on the command line parameter. 1898 Even with TSX enabled, the kernel will attempt to enable the best 1899 possible TAA mitigation setting depending on the microcode available 1900 for the particular machine. 1901 1902 This option allows to set the default tsx mode between tsx=on, =off 1903 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1904 details. 1905 1906 Say off if not sure, auto if TSX is in use but it should be used on safe 1907 platforms or on if TSX is in use and the security aspect of tsx is not 1908 relevant. 1909 1910config X86_INTEL_TSX_MODE_OFF 1911 bool "off" 1912 help 1913 TSX is disabled if possible - equals to tsx=off command line parameter. 1914 1915config X86_INTEL_TSX_MODE_ON 1916 bool "on" 1917 help 1918 TSX is always enabled on TSX capable HW - equals the tsx=on command 1919 line parameter. 1920 1921config X86_INTEL_TSX_MODE_AUTO 1922 bool "auto" 1923 help 1924 TSX is enabled on TSX capable HW that is believed to be safe against 1925 side channel attacks- equals the tsx=auto command line parameter. 1926endchoice 1927 1928config EFI 1929 bool "EFI runtime service support" 1930 depends on ACPI 1931 select UCS2_STRING 1932 select EFI_RUNTIME_WRAPPERS 1933 select ARCH_USE_MEMREMAP_PROT 1934 help 1935 This enables the kernel to use EFI runtime services that are 1936 available (such as the EFI variable services). 1937 1938 This option is only useful on systems that have EFI firmware. 1939 In addition, you should use the latest ELILO loader available 1940 at <http://elilo.sourceforge.net> in order to take advantage 1941 of EFI runtime services. However, even with this option, the 1942 resultant kernel should continue to boot on existing non-EFI 1943 platforms. 1944 1945config EFI_STUB 1946 bool "EFI stub support" 1947 depends on EFI && !X86_USE_3DNOW 1948 select RELOCATABLE 1949 help 1950 This kernel feature allows a bzImage to be loaded directly 1951 by EFI firmware without the use of a bootloader. 1952 1953 See Documentation/admin-guide/efi-stub.rst for more information. 1954 1955config EFI_MIXED 1956 bool "EFI mixed-mode support" 1957 depends on EFI_STUB && X86_64 1958 help 1959 Enabling this feature allows a 64-bit kernel to be booted 1960 on a 32-bit firmware, provided that your CPU supports 64-bit 1961 mode. 1962 1963 Note that it is not possible to boot a mixed-mode enabled 1964 kernel via the EFI boot stub - a bootloader that supports 1965 the EFI handover protocol must be used. 1966 1967 If unsure, say N. 1968 1969source "kernel/Kconfig.hz" 1970 1971config KEXEC 1972 bool "kexec system call" 1973 select KEXEC_CORE 1974 help 1975 kexec is a system call that implements the ability to shutdown your 1976 current kernel, and to start another kernel. It is like a reboot 1977 but it is independent of the system firmware. And like a reboot 1978 you can start any kernel with it, not just Linux. 1979 1980 The name comes from the similarity to the exec system call. 1981 1982 It is an ongoing process to be certain the hardware in a machine 1983 is properly shutdown, so do not be surprised if this code does not 1984 initially work for you. As of this writing the exact hardware 1985 interface is strongly in flux, so no good recommendation can be 1986 made. 1987 1988config KEXEC_FILE 1989 bool "kexec file based system call" 1990 select KEXEC_CORE 1991 select BUILD_BIN2C 1992 depends on X86_64 1993 depends on CRYPTO=y 1994 depends on CRYPTO_SHA256=y 1995 help 1996 This is new version of kexec system call. This system call is 1997 file based and takes file descriptors as system call argument 1998 for kernel and initramfs as opposed to list of segments as 1999 accepted by previous system call. 2000 2001config ARCH_HAS_KEXEC_PURGATORY 2002 def_bool KEXEC_FILE 2003 2004config KEXEC_SIG 2005 bool "Verify kernel signature during kexec_file_load() syscall" 2006 depends on KEXEC_FILE 2007 help 2008 2009 This option makes the kexec_file_load() syscall check for a valid 2010 signature of the kernel image. The image can still be loaded without 2011 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2012 there's a signature that we can check, then it must be valid. 2013 2014 In addition to this option, you need to enable signature 2015 verification for the corresponding kernel image type being 2016 loaded in order for this to work. 2017 2018config KEXEC_SIG_FORCE 2019 bool "Require a valid signature in kexec_file_load() syscall" 2020 depends on KEXEC_SIG 2021 help 2022 This option makes kernel signature verification mandatory for 2023 the kexec_file_load() syscall. 2024 2025config KEXEC_BZIMAGE_VERIFY_SIG 2026 bool "Enable bzImage signature verification support" 2027 depends on KEXEC_SIG 2028 depends on SIGNED_PE_FILE_VERIFICATION 2029 select SYSTEM_TRUSTED_KEYRING 2030 help 2031 Enable bzImage signature verification support. 2032 2033config CRASH_DUMP 2034 bool "kernel crash dumps" 2035 depends on X86_64 || (X86_32 && HIGHMEM) 2036 help 2037 Generate crash dump after being started by kexec. 2038 This should be normally only set in special crash dump kernels 2039 which are loaded in the main kernel with kexec-tools into 2040 a specially reserved region and then later executed after 2041 a crash by kdump/kexec. The crash dump kernel must be compiled 2042 to a memory address not used by the main kernel or BIOS using 2043 PHYSICAL_START, or it must be built as a relocatable image 2044 (CONFIG_RELOCATABLE=y). 2045 For more details see Documentation/admin-guide/kdump/kdump.rst 2046 2047config KEXEC_JUMP 2048 bool "kexec jump" 2049 depends on KEXEC && HIBERNATION 2050 help 2051 Jump between original kernel and kexeced kernel and invoke 2052 code in physical address mode via KEXEC 2053 2054config PHYSICAL_START 2055 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2056 default "0x1000000" 2057 help 2058 This gives the physical address where the kernel is loaded. 2059 2060 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2061 bzImage will decompress itself to above physical address and 2062 run from there. Otherwise, bzImage will run from the address where 2063 it has been loaded by the boot loader and will ignore above physical 2064 address. 2065 2066 In normal kdump cases one does not have to set/change this option 2067 as now bzImage can be compiled as a completely relocatable image 2068 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2069 address. This option is mainly useful for the folks who don't want 2070 to use a bzImage for capturing the crash dump and want to use a 2071 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2072 to be specifically compiled to run from a specific memory area 2073 (normally a reserved region) and this option comes handy. 2074 2075 So if you are using bzImage for capturing the crash dump, 2076 leave the value here unchanged to 0x1000000 and set 2077 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2078 for capturing the crash dump change this value to start of 2079 the reserved region. In other words, it can be set based on 2080 the "X" value as specified in the "crashkernel=YM@XM" 2081 command line boot parameter passed to the panic-ed 2082 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2083 for more details about crash dumps. 2084 2085 Usage of bzImage for capturing the crash dump is recommended as 2086 one does not have to build two kernels. Same kernel can be used 2087 as production kernel and capture kernel. Above option should have 2088 gone away after relocatable bzImage support is introduced. But it 2089 is present because there are users out there who continue to use 2090 vmlinux for dump capture. This option should go away down the 2091 line. 2092 2093 Don't change this unless you know what you are doing. 2094 2095config RELOCATABLE 2096 bool "Build a relocatable kernel" 2097 default y 2098 help 2099 This builds a kernel image that retains relocation information 2100 so it can be loaded someplace besides the default 1MB. 2101 The relocations tend to make the kernel binary about 10% larger, 2102 but are discarded at runtime. 2103 2104 One use is for the kexec on panic case where the recovery kernel 2105 must live at a different physical address than the primary 2106 kernel. 2107 2108 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2109 it has been loaded at and the compile time physical address 2110 (CONFIG_PHYSICAL_START) is used as the minimum location. 2111 2112config RANDOMIZE_BASE 2113 bool "Randomize the address of the kernel image (KASLR)" 2114 depends on RELOCATABLE 2115 default y 2116 help 2117 In support of Kernel Address Space Layout Randomization (KASLR), 2118 this randomizes the physical address at which the kernel image 2119 is decompressed and the virtual address where the kernel 2120 image is mapped, as a security feature that deters exploit 2121 attempts relying on knowledge of the location of kernel 2122 code internals. 2123 2124 On 64-bit, the kernel physical and virtual addresses are 2125 randomized separately. The physical address will be anywhere 2126 between 16MB and the top of physical memory (up to 64TB). The 2127 virtual address will be randomized from 16MB up to 1GB (9 bits 2128 of entropy). Note that this also reduces the memory space 2129 available to kernel modules from 1.5GB to 1GB. 2130 2131 On 32-bit, the kernel physical and virtual addresses are 2132 randomized together. They will be randomized from 16MB up to 2133 512MB (8 bits of entropy). 2134 2135 Entropy is generated using the RDRAND instruction if it is 2136 supported. If RDTSC is supported, its value is mixed into 2137 the entropy pool as well. If neither RDRAND nor RDTSC are 2138 supported, then entropy is read from the i8254 timer. The 2139 usable entropy is limited by the kernel being built using 2140 2GB addressing, and that PHYSICAL_ALIGN must be at a 2141 minimum of 2MB. As a result, only 10 bits of entropy are 2142 theoretically possible, but the implementations are further 2143 limited due to memory layouts. 2144 2145 If unsure, say Y. 2146 2147# Relocation on x86 needs some additional build support 2148config X86_NEED_RELOCS 2149 def_bool y 2150 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2151 2152config PHYSICAL_ALIGN 2153 hex "Alignment value to which kernel should be aligned" 2154 default "0x200000" 2155 range 0x2000 0x1000000 if X86_32 2156 range 0x200000 0x1000000 if X86_64 2157 help 2158 This value puts the alignment restrictions on physical address 2159 where kernel is loaded and run from. Kernel is compiled for an 2160 address which meets above alignment restriction. 2161 2162 If bootloader loads the kernel at a non-aligned address and 2163 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2164 address aligned to above value and run from there. 2165 2166 If bootloader loads the kernel at a non-aligned address and 2167 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2168 load address and decompress itself to the address it has been 2169 compiled for and run from there. The address for which kernel is 2170 compiled already meets above alignment restrictions. Hence the 2171 end result is that kernel runs from a physical address meeting 2172 above alignment restrictions. 2173 2174 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2175 this value must be a multiple of 0x200000. 2176 2177 Don't change this unless you know what you are doing. 2178 2179config DYNAMIC_MEMORY_LAYOUT 2180 bool 2181 help 2182 This option makes base addresses of vmalloc and vmemmap as well as 2183 __PAGE_OFFSET movable during boot. 2184 2185config RANDOMIZE_MEMORY 2186 bool "Randomize the kernel memory sections" 2187 depends on X86_64 2188 depends on RANDOMIZE_BASE 2189 select DYNAMIC_MEMORY_LAYOUT 2190 default RANDOMIZE_BASE 2191 help 2192 Randomizes the base virtual address of kernel memory sections 2193 (physical memory mapping, vmalloc & vmemmap). This security feature 2194 makes exploits relying on predictable memory locations less reliable. 2195 2196 The order of allocations remains unchanged. Entropy is generated in 2197 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2198 configuration have in average 30,000 different possible virtual 2199 addresses for each memory section. 2200 2201 If unsure, say Y. 2202 2203config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2204 hex "Physical memory mapping padding" if EXPERT 2205 depends on RANDOMIZE_MEMORY 2206 default "0xa" if MEMORY_HOTPLUG 2207 default "0x0" 2208 range 0x1 0x40 if MEMORY_HOTPLUG 2209 range 0x0 0x40 2210 help 2211 Define the padding in terabytes added to the existing physical 2212 memory size during kernel memory randomization. It is useful 2213 for memory hotplug support but reduces the entropy available for 2214 address randomization. 2215 2216 If unsure, leave at the default value. 2217 2218config HOTPLUG_CPU 2219 def_bool y 2220 depends on SMP 2221 2222config BOOTPARAM_HOTPLUG_CPU0 2223 bool "Set default setting of cpu0_hotpluggable" 2224 depends on HOTPLUG_CPU 2225 help 2226 Set whether default state of cpu0_hotpluggable is on or off. 2227 2228 Say Y here to enable CPU0 hotplug by default. If this switch 2229 is turned on, there is no need to give cpu0_hotplug kernel 2230 parameter and the CPU0 hotplug feature is enabled by default. 2231 2232 Please note: there are two known CPU0 dependencies if you want 2233 to enable the CPU0 hotplug feature either by this switch or by 2234 cpu0_hotplug kernel parameter. 2235 2236 First, resume from hibernate or suspend always starts from CPU0. 2237 So hibernate and suspend are prevented if CPU0 is offline. 2238 2239 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2240 offline if any interrupt can not migrate out of CPU0. There may 2241 be other CPU0 dependencies. 2242 2243 Please make sure the dependencies are under your control before 2244 you enable this feature. 2245 2246 Say N if you don't want to enable CPU0 hotplug feature by default. 2247 You still can enable the CPU0 hotplug feature at boot by kernel 2248 parameter cpu0_hotplug. 2249 2250config DEBUG_HOTPLUG_CPU0 2251 def_bool n 2252 prompt "Debug CPU0 hotplug" 2253 depends on HOTPLUG_CPU 2254 help 2255 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2256 soon as possible and boots up userspace with CPU0 offlined. User 2257 can online CPU0 back after boot time. 2258 2259 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2260 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2261 compilation or giving cpu0_hotplug kernel parameter at boot. 2262 2263 If unsure, say N. 2264 2265config COMPAT_VDSO 2266 def_bool n 2267 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2268 depends on COMPAT_32 2269 help 2270 Certain buggy versions of glibc will crash if they are 2271 presented with a 32-bit vDSO that is not mapped at the address 2272 indicated in its segment table. 2273 2274 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2275 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2276 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2277 the only released version with the bug, but OpenSUSE 9 2278 contains a buggy "glibc 2.3.2". 2279 2280 The symptom of the bug is that everything crashes on startup, saying: 2281 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2282 2283 Saying Y here changes the default value of the vdso32 boot 2284 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2285 This works around the glibc bug but hurts performance. 2286 2287 If unsure, say N: if you are compiling your own kernel, you 2288 are unlikely to be using a buggy version of glibc. 2289 2290choice 2291 prompt "vsyscall table for legacy applications" 2292 depends on X86_64 2293 default LEGACY_VSYSCALL_XONLY 2294 help 2295 Legacy user code that does not know how to find the vDSO expects 2296 to be able to issue three syscalls by calling fixed addresses in 2297 kernel space. Since this location is not randomized with ASLR, 2298 it can be used to assist security vulnerability exploitation. 2299 2300 This setting can be changed at boot time via the kernel command 2301 line parameter vsyscall=[emulate|xonly|none]. 2302 2303 On a system with recent enough glibc (2.14 or newer) and no 2304 static binaries, you can say None without a performance penalty 2305 to improve security. 2306 2307 If unsure, select "Emulate execution only". 2308 2309 config LEGACY_VSYSCALL_EMULATE 2310 bool "Full emulation" 2311 help 2312 The kernel traps and emulates calls into the fixed vsyscall 2313 address mapping. This makes the mapping non-executable, but 2314 it still contains readable known contents, which could be 2315 used in certain rare security vulnerability exploits. This 2316 configuration is recommended when using legacy userspace 2317 that still uses vsyscalls along with legacy binary 2318 instrumentation tools that require code to be readable. 2319 2320 An example of this type of legacy userspace is running 2321 Pin on an old binary that still uses vsyscalls. 2322 2323 config LEGACY_VSYSCALL_XONLY 2324 bool "Emulate execution only" 2325 help 2326 The kernel traps and emulates calls into the fixed vsyscall 2327 address mapping and does not allow reads. This 2328 configuration is recommended when userspace might use the 2329 legacy vsyscall area but support for legacy binary 2330 instrumentation of legacy code is not needed. It mitigates 2331 certain uses of the vsyscall area as an ASLR-bypassing 2332 buffer. 2333 2334 config LEGACY_VSYSCALL_NONE 2335 bool "None" 2336 help 2337 There will be no vsyscall mapping at all. This will 2338 eliminate any risk of ASLR bypass due to the vsyscall 2339 fixed address mapping. Attempts to use the vsyscalls 2340 will be reported to dmesg, so that either old or 2341 malicious userspace programs can be identified. 2342 2343endchoice 2344 2345config CMDLINE_BOOL 2346 bool "Built-in kernel command line" 2347 help 2348 Allow for specifying boot arguments to the kernel at 2349 build time. On some systems (e.g. embedded ones), it is 2350 necessary or convenient to provide some or all of the 2351 kernel boot arguments with the kernel itself (that is, 2352 to not rely on the boot loader to provide them.) 2353 2354 To compile command line arguments into the kernel, 2355 set this option to 'Y', then fill in the 2356 boot arguments in CONFIG_CMDLINE. 2357 2358 Systems with fully functional boot loaders (i.e. non-embedded) 2359 should leave this option set to 'N'. 2360 2361config CMDLINE 2362 string "Built-in kernel command string" 2363 depends on CMDLINE_BOOL 2364 default "" 2365 help 2366 Enter arguments here that should be compiled into the kernel 2367 image and used at boot time. If the boot loader provides a 2368 command line at boot time, it is appended to this string to 2369 form the full kernel command line, when the system boots. 2370 2371 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2372 change this behavior. 2373 2374 In most cases, the command line (whether built-in or provided 2375 by the boot loader) should specify the device for the root 2376 file system. 2377 2378config CMDLINE_OVERRIDE 2379 bool "Built-in command line overrides boot loader arguments" 2380 depends on CMDLINE_BOOL && CMDLINE != "" 2381 help 2382 Set this option to 'Y' to have the kernel ignore the boot loader 2383 command line, and use ONLY the built-in command line. 2384 2385 This is used to work around broken boot loaders. This should 2386 be set to 'N' under normal conditions. 2387 2388config MODIFY_LDT_SYSCALL 2389 bool "Enable the LDT (local descriptor table)" if EXPERT 2390 default y 2391 help 2392 Linux can allow user programs to install a per-process x86 2393 Local Descriptor Table (LDT) using the modify_ldt(2) system 2394 call. This is required to run 16-bit or segmented code such as 2395 DOSEMU or some Wine programs. It is also used by some very old 2396 threading libraries. 2397 2398 Enabling this feature adds a small amount of overhead to 2399 context switches and increases the low-level kernel attack 2400 surface. Disabling it removes the modify_ldt(2) system call. 2401 2402 Saying 'N' here may make sense for embedded or server kernels. 2403 2404source "kernel/livepatch/Kconfig" 2405 2406endmenu 2407 2408config CC_HAS_SLS 2409 def_bool $(cc-option,-mharden-sls=all) 2410 2411config CC_HAS_RETURN_THUNK 2412 def_bool $(cc-option,-mfunction-return=thunk-extern) 2413 2414menuconfig SPECULATION_MITIGATIONS 2415 bool "Mitigations for speculative execution vulnerabilities" 2416 default y 2417 help 2418 Say Y here to enable options which enable mitigations for 2419 speculative execution hardware vulnerabilities. 2420 2421 If you say N, all mitigations will be disabled. You really 2422 should know what you are doing to say so. 2423 2424if SPECULATION_MITIGATIONS 2425 2426config PAGE_TABLE_ISOLATION 2427 bool "Remove the kernel mapping in user mode" 2428 default y 2429 depends on (X86_64 || X86_PAE) 2430 help 2431 This feature reduces the number of hardware side channels by 2432 ensuring that the majority of kernel addresses are not mapped 2433 into userspace. 2434 2435 See Documentation/x86/pti.rst for more details. 2436 2437config RETPOLINE 2438 bool "Avoid speculative indirect branches in kernel" 2439 default y 2440 help 2441 Compile kernel with the retpoline compiler options to guard against 2442 kernel-to-user data leaks by avoiding speculative indirect 2443 branches. Requires a compiler with -mindirect-branch=thunk-extern 2444 support for full protection. The kernel may run slower. 2445 2446config RETHUNK 2447 bool "Enable return-thunks" 2448 depends on RETPOLINE && CC_HAS_RETURN_THUNK 2449 default y if X86_64 2450 help 2451 Compile the kernel with the return-thunks compiler option to guard 2452 against kernel-to-user data leaks by avoiding return speculation. 2453 Requires a compiler with -mfunction-return=thunk-extern 2454 support for full protection. The kernel may run slower. 2455 2456config CPU_UNRET_ENTRY 2457 bool "Enable UNRET on kernel entry" 2458 depends on CPU_SUP_AMD && RETHUNK && X86_64 2459 default y 2460 help 2461 Compile the kernel with support for the retbleed=unret mitigation. 2462 2463config CPU_IBPB_ENTRY 2464 bool "Enable IBPB on kernel entry" 2465 depends on CPU_SUP_AMD && X86_64 2466 default y 2467 help 2468 Compile the kernel with support for the retbleed=ibpb mitigation. 2469 2470config CPU_IBRS_ENTRY 2471 bool "Enable IBRS on kernel entry" 2472 depends on CPU_SUP_INTEL && X86_64 2473 default y 2474 help 2475 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2476 This mitigates both spectre_v2 and retbleed at great cost to 2477 performance. 2478 2479config CPU_SRSO 2480 bool "Mitigate speculative RAS overflow on AMD" 2481 depends on CPU_SUP_AMD && X86_64 && RETHUNK 2482 default y 2483 help 2484 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2485 2486config SLS 2487 bool "Mitigate Straight-Line-Speculation" 2488 depends on CC_HAS_SLS && X86_64 2489 default n 2490 help 2491 Compile the kernel with straight-line-speculation options to guard 2492 against straight line speculation. The kernel image might be slightly 2493 larger. 2494 2495config GDS_FORCE_MITIGATION 2496 bool "Force GDS Mitigation" 2497 depends on CPU_SUP_INTEL 2498 default n 2499 help 2500 Gather Data Sampling (GDS) is a hardware vulnerability which allows 2501 unprivileged speculative access to data which was previously stored in 2502 vector registers. 2503 2504 This option is equivalent to setting gather_data_sampling=force on the 2505 command line. The microcode mitigation is used if present, otherwise 2506 AVX is disabled as a mitigation. On affected systems that are missing 2507 the microcode any userspace code that unconditionally uses AVX will 2508 break with this option set. 2509 2510 Setting this option on systems not vulnerable to GDS has no effect. 2511 2512 If in doubt, say N. 2513 2514endif 2515 2516config ARCH_HAS_ADD_PAGES 2517 def_bool y 2518 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2519 2520config ARCH_ENABLE_MEMORY_HOTPLUG 2521 def_bool y 2522 depends on X86_64 || (X86_32 && HIGHMEM) 2523 2524config ARCH_ENABLE_MEMORY_HOTREMOVE 2525 def_bool y 2526 depends on MEMORY_HOTPLUG 2527 2528config USE_PERCPU_NUMA_NODE_ID 2529 def_bool y 2530 depends on NUMA 2531 2532config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2533 def_bool y 2534 depends on X86_64 || X86_PAE 2535 2536config ARCH_ENABLE_HUGEPAGE_MIGRATION 2537 def_bool y 2538 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2539 2540config ARCH_ENABLE_THP_MIGRATION 2541 def_bool y 2542 depends on X86_64 && TRANSPARENT_HUGEPAGE 2543 2544menu "Power management and ACPI options" 2545 2546config ARCH_HIBERNATION_HEADER 2547 def_bool y 2548 depends on HIBERNATION 2549 2550source "kernel/power/Kconfig" 2551 2552source "drivers/acpi/Kconfig" 2553 2554source "drivers/sfi/Kconfig" 2555 2556config X86_APM_BOOT 2557 def_bool y 2558 depends on APM 2559 2560menuconfig APM 2561 tristate "APM (Advanced Power Management) BIOS support" 2562 depends on X86_32 && PM_SLEEP 2563 help 2564 APM is a BIOS specification for saving power using several different 2565 techniques. This is mostly useful for battery powered laptops with 2566 APM compliant BIOSes. If you say Y here, the system time will be 2567 reset after a RESUME operation, the /proc/apm device will provide 2568 battery status information, and user-space programs will receive 2569 notification of APM "events" (e.g. battery status change). 2570 2571 If you select "Y" here, you can disable actual use of the APM 2572 BIOS by passing the "apm=off" option to the kernel at boot time. 2573 2574 Note that the APM support is almost completely disabled for 2575 machines with more than one CPU. 2576 2577 In order to use APM, you will need supporting software. For location 2578 and more information, read <file:Documentation/power/apm-acpi.rst> 2579 and the Battery Powered Linux mini-HOWTO, available from 2580 <http://www.tldp.org/docs.html#howto>. 2581 2582 This driver does not spin down disk drives (see the hdparm(8) 2583 manpage ("man 8 hdparm") for that), and it doesn't turn off 2584 VESA-compliant "green" monitors. 2585 2586 This driver does not support the TI 4000M TravelMate and the ACER 2587 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2588 desktop machines also don't have compliant BIOSes, and this driver 2589 may cause those machines to panic during the boot phase. 2590 2591 Generally, if you don't have a battery in your machine, there isn't 2592 much point in using this driver and you should say N. If you get 2593 random kernel OOPSes or reboots that don't seem to be related to 2594 anything, try disabling/enabling this option (or disabling/enabling 2595 APM in your BIOS). 2596 2597 Some other things you should try when experiencing seemingly random, 2598 "weird" problems: 2599 2600 1) make sure that you have enough swap space and that it is 2601 enabled. 2602 2) pass the "no-hlt" option to the kernel 2603 3) switch on floating point emulation in the kernel and pass 2604 the "no387" option to the kernel 2605 4) pass the "floppy=nodma" option to the kernel 2606 5) pass the "mem=4M" option to the kernel (thereby disabling 2607 all but the first 4 MB of RAM) 2608 6) make sure that the CPU is not over clocked. 2609 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2610 8) disable the cache from your BIOS settings 2611 9) install a fan for the video card or exchange video RAM 2612 10) install a better fan for the CPU 2613 11) exchange RAM chips 2614 12) exchange the motherboard. 2615 2616 To compile this driver as a module, choose M here: the 2617 module will be called apm. 2618 2619if APM 2620 2621config APM_IGNORE_USER_SUSPEND 2622 bool "Ignore USER SUSPEND" 2623 help 2624 This option will ignore USER SUSPEND requests. On machines with a 2625 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2626 series notebooks, it is necessary to say Y because of a BIOS bug. 2627 2628config APM_DO_ENABLE 2629 bool "Enable PM at boot time" 2630 help 2631 Enable APM features at boot time. From page 36 of the APM BIOS 2632 specification: "When disabled, the APM BIOS does not automatically 2633 power manage devices, enter the Standby State, enter the Suspend 2634 State, or take power saving steps in response to CPU Idle calls." 2635 This driver will make CPU Idle calls when Linux is idle (unless this 2636 feature is turned off -- see "Do CPU IDLE calls", below). This 2637 should always save battery power, but more complicated APM features 2638 will be dependent on your BIOS implementation. You may need to turn 2639 this option off if your computer hangs at boot time when using APM 2640 support, or if it beeps continuously instead of suspending. Turn 2641 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2642 T400CDT. This is off by default since most machines do fine without 2643 this feature. 2644 2645config APM_CPU_IDLE 2646 depends on CPU_IDLE 2647 bool "Make CPU Idle calls when idle" 2648 help 2649 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2650 On some machines, this can activate improved power savings, such as 2651 a slowed CPU clock rate, when the machine is idle. These idle calls 2652 are made after the idle loop has run for some length of time (e.g., 2653 333 mS). On some machines, this will cause a hang at boot time or 2654 whenever the CPU becomes idle. (On machines with more than one CPU, 2655 this option does nothing.) 2656 2657config APM_DISPLAY_BLANK 2658 bool "Enable console blanking using APM" 2659 help 2660 Enable console blanking using the APM. Some laptops can use this to 2661 turn off the LCD backlight when the screen blanker of the Linux 2662 virtual console blanks the screen. Note that this is only used by 2663 the virtual console screen blanker, and won't turn off the backlight 2664 when using the X Window system. This also doesn't have anything to 2665 do with your VESA-compliant power-saving monitor. Further, this 2666 option doesn't work for all laptops -- it might not turn off your 2667 backlight at all, or it might print a lot of errors to the console, 2668 especially if you are using gpm. 2669 2670config APM_ALLOW_INTS 2671 bool "Allow interrupts during APM BIOS calls" 2672 help 2673 Normally we disable external interrupts while we are making calls to 2674 the APM BIOS as a measure to lessen the effects of a badly behaving 2675 BIOS implementation. The BIOS should reenable interrupts if it 2676 needs to. Unfortunately, some BIOSes do not -- especially those in 2677 many of the newer IBM Thinkpads. If you experience hangs when you 2678 suspend, try setting this to Y. Otherwise, say N. 2679 2680endif # APM 2681 2682source "drivers/cpufreq/Kconfig" 2683 2684source "drivers/cpuidle/Kconfig" 2685 2686source "drivers/idle/Kconfig" 2687 2688endmenu 2689 2690 2691menu "Bus options (PCI etc.)" 2692 2693choice 2694 prompt "PCI access mode" 2695 depends on X86_32 && PCI 2696 default PCI_GOANY 2697 help 2698 On PCI systems, the BIOS can be used to detect the PCI devices and 2699 determine their configuration. However, some old PCI motherboards 2700 have BIOS bugs and may crash if this is done. Also, some embedded 2701 PCI-based systems don't have any BIOS at all. Linux can also try to 2702 detect the PCI hardware directly without using the BIOS. 2703 2704 With this option, you can specify how Linux should detect the 2705 PCI devices. If you choose "BIOS", the BIOS will be used, 2706 if you choose "Direct", the BIOS won't be used, and if you 2707 choose "MMConfig", then PCI Express MMCONFIG will be used. 2708 If you choose "Any", the kernel will try MMCONFIG, then the 2709 direct access method and falls back to the BIOS if that doesn't 2710 work. If unsure, go with the default, which is "Any". 2711 2712config PCI_GOBIOS 2713 bool "BIOS" 2714 2715config PCI_GOMMCONFIG 2716 bool "MMConfig" 2717 2718config PCI_GODIRECT 2719 bool "Direct" 2720 2721config PCI_GOOLPC 2722 bool "OLPC XO-1" 2723 depends on OLPC 2724 2725config PCI_GOANY 2726 bool "Any" 2727 2728endchoice 2729 2730config PCI_BIOS 2731 def_bool y 2732 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2733 2734# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2735config PCI_DIRECT 2736 def_bool y 2737 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2738 2739config PCI_MMCONFIG 2740 bool "Support mmconfig PCI config space access" if X86_64 2741 default y 2742 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2743 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2744 2745config PCI_OLPC 2746 def_bool y 2747 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2748 2749config PCI_XEN 2750 def_bool y 2751 depends on PCI && XEN 2752 select SWIOTLB_XEN 2753 2754config MMCONF_FAM10H 2755 def_bool y 2756 depends on X86_64 && PCI_MMCONFIG && ACPI 2757 2758config PCI_CNB20LE_QUIRK 2759 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2760 depends on PCI 2761 help 2762 Read the PCI windows out of the CNB20LE host bridge. This allows 2763 PCI hotplug to work on systems with the CNB20LE chipset which do 2764 not have ACPI. 2765 2766 There's no public spec for this chipset, and this functionality 2767 is known to be incomplete. 2768 2769 You should say N unless you know you need this. 2770 2771config ISA_BUS 2772 bool "ISA bus support on modern systems" if EXPERT 2773 help 2774 Expose ISA bus device drivers and options available for selection and 2775 configuration. Enable this option if your target machine has an ISA 2776 bus. ISA is an older system, displaced by PCI and newer bus 2777 architectures -- if your target machine is modern, it probably does 2778 not have an ISA bus. 2779 2780 If unsure, say N. 2781 2782# x86_64 have no ISA slots, but can have ISA-style DMA. 2783config ISA_DMA_API 2784 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2785 default y 2786 help 2787 Enables ISA-style DMA support for devices requiring such controllers. 2788 If unsure, say Y. 2789 2790if X86_32 2791 2792config ISA 2793 bool "ISA support" 2794 help 2795 Find out whether you have ISA slots on your motherboard. ISA is the 2796 name of a bus system, i.e. the way the CPU talks to the other stuff 2797 inside your box. Other bus systems are PCI, EISA, MicroChannel 2798 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2799 newer boards don't support it. If you have ISA, say Y, otherwise N. 2800 2801config SCx200 2802 tristate "NatSemi SCx200 support" 2803 help 2804 This provides basic support for National Semiconductor's 2805 (now AMD's) Geode processors. The driver probes for the 2806 PCI-IDs of several on-chip devices, so its a good dependency 2807 for other scx200_* drivers. 2808 2809 If compiled as a module, the driver is named scx200. 2810 2811config SCx200HR_TIMER 2812 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2813 depends on SCx200 2814 default y 2815 help 2816 This driver provides a clocksource built upon the on-chip 2817 27MHz high-resolution timer. Its also a workaround for 2818 NSC Geode SC-1100's buggy TSC, which loses time when the 2819 processor goes idle (as is done by the scheduler). The 2820 other workaround is idle=poll boot option. 2821 2822config OLPC 2823 bool "One Laptop Per Child support" 2824 depends on !X86_PAE 2825 select GPIOLIB 2826 select OF 2827 select OF_PROMTREE 2828 select IRQ_DOMAIN 2829 select OLPC_EC 2830 help 2831 Add support for detecting the unique features of the OLPC 2832 XO hardware. 2833 2834config OLPC_XO1_PM 2835 bool "OLPC XO-1 Power Management" 2836 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2837 help 2838 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2839 2840config OLPC_XO1_RTC 2841 bool "OLPC XO-1 Real Time Clock" 2842 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2843 help 2844 Add support for the XO-1 real time clock, which can be used as a 2845 programmable wakeup source. 2846 2847config OLPC_XO1_SCI 2848 bool "OLPC XO-1 SCI extras" 2849 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2850 depends on INPUT=y 2851 select POWER_SUPPLY 2852 help 2853 Add support for SCI-based features of the OLPC XO-1 laptop: 2854 - EC-driven system wakeups 2855 - Power button 2856 - Ebook switch 2857 - Lid switch 2858 - AC adapter status updates 2859 - Battery status updates 2860 2861config OLPC_XO15_SCI 2862 bool "OLPC XO-1.5 SCI extras" 2863 depends on OLPC && ACPI 2864 select POWER_SUPPLY 2865 help 2866 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2867 - EC-driven system wakeups 2868 - AC adapter status updates 2869 - Battery status updates 2870 2871config ALIX 2872 bool "PCEngines ALIX System Support (LED setup)" 2873 select GPIOLIB 2874 help 2875 This option enables system support for the PCEngines ALIX. 2876 At present this just sets up LEDs for GPIO control on 2877 ALIX2/3/6 boards. However, other system specific setup should 2878 get added here. 2879 2880 Note: You must still enable the drivers for GPIO and LED support 2881 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2882 2883 Note: You have to set alix.force=1 for boards with Award BIOS. 2884 2885config NET5501 2886 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2887 select GPIOLIB 2888 help 2889 This option enables system support for the Soekris Engineering net5501. 2890 2891config GEOS 2892 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2893 select GPIOLIB 2894 depends on DMI 2895 help 2896 This option enables system support for the Traverse Technologies GEOS. 2897 2898config TS5500 2899 bool "Technologic Systems TS-5500 platform support" 2900 depends on MELAN 2901 select CHECK_SIGNATURE 2902 select NEW_LEDS 2903 select LEDS_CLASS 2904 help 2905 This option enables system support for the Technologic Systems TS-5500. 2906 2907endif # X86_32 2908 2909config AMD_NB 2910 def_bool y 2911 depends on CPU_SUP_AMD && PCI 2912 2913config X86_SYSFB 2914 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2915 help 2916 Firmwares often provide initial graphics framebuffers so the BIOS, 2917 bootloader or kernel can show basic video-output during boot for 2918 user-guidance and debugging. Historically, x86 used the VESA BIOS 2919 Extensions and EFI-framebuffers for this, which are mostly limited 2920 to x86. 2921 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2922 framebuffers so the new generic system-framebuffer drivers can be 2923 used on x86. If the framebuffer is not compatible with the generic 2924 modes, it is advertised as fallback platform framebuffer so legacy 2925 drivers like efifb, vesafb and uvesafb can pick it up. 2926 If this option is not selected, all system framebuffers are always 2927 marked as fallback platform framebuffers as usual. 2928 2929 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2930 not be able to pick up generic system framebuffers if this option 2931 is selected. You are highly encouraged to enable simplefb as 2932 replacement if you select this option. simplefb can correctly deal 2933 with generic system framebuffers. But you should still keep vesafb 2934 and others enabled as fallback if a system framebuffer is 2935 incompatible with simplefb. 2936 2937 If unsure, say Y. 2938 2939endmenu 2940 2941 2942menu "Binary Emulations" 2943 2944config IA32_EMULATION 2945 bool "IA32 Emulation" 2946 depends on X86_64 2947 select ARCH_WANT_OLD_COMPAT_IPC 2948 select BINFMT_ELF 2949 select COMPAT_BINFMT_ELF 2950 select COMPAT_OLD_SIGACTION 2951 help 2952 Include code to run legacy 32-bit programs under a 2953 64-bit kernel. You should likely turn this on, unless you're 2954 100% sure that you don't have any 32-bit programs left. 2955 2956config IA32_AOUT 2957 tristate "IA32 a.out support" 2958 depends on IA32_EMULATION 2959 depends on BROKEN 2960 help 2961 Support old a.out binaries in the 32bit emulation. 2962 2963config X86_X32 2964 bool "x32 ABI for 64-bit mode" 2965 depends on X86_64 2966 # llvm-objcopy does not convert x86_64 .note.gnu.property or 2967 # compressed debug sections to x86_x32 properly: 2968 # https://github.com/ClangBuiltLinux/linux/issues/514 2969 # https://github.com/ClangBuiltLinux/linux/issues/1141 2970 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2971 help 2972 Include code to run binaries for the x32 native 32-bit ABI 2973 for 64-bit processors. An x32 process gets access to the 2974 full 64-bit register file and wide data path while leaving 2975 pointers at 32 bits for smaller memory footprint. 2976 2977 You will need a recent binutils (2.22 or later) with 2978 elf32_x86_64 support enabled to compile a kernel with this 2979 option set. 2980 2981config COMPAT_32 2982 def_bool y 2983 depends on IA32_EMULATION || X86_32 2984 select HAVE_UID16 2985 select OLD_SIGSUSPEND3 2986 2987config COMPAT 2988 def_bool y 2989 depends on IA32_EMULATION || X86_X32 2990 2991if COMPAT 2992config COMPAT_FOR_U64_ALIGNMENT 2993 def_bool y 2994 2995config SYSVIPC_COMPAT 2996 def_bool y 2997 depends on SYSVIPC 2998endif 2999 3000endmenu 3001 3002 3003config HAVE_ATOMIC_IOMAP 3004 def_bool y 3005 depends on X86_32 3006 3007source "drivers/firmware/Kconfig" 3008 3009source "arch/x86/kvm/Kconfig" 3010 3011source "arch/x86/Kconfig.assembler" 3012