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 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 34config FORCE_DYNAMIC_FTRACE 35 def_bool y 36 depends on X86_32 37 depends on FUNCTION_TRACER 38 select DYNAMIC_FTRACE 39 help 40 We keep the static function tracing (!DYNAMIC_FTRACE) around 41 in order to test the non static function tracing in the 42 generic code, as other architectures still use it. But we 43 only need to keep it around for x86_64. No need to keep it 44 for x86_32. For x86_32, force DYNAMIC_FTRACE. 45# 46# Arch settings 47# 48# ( Note that options that are marked 'if X86_64' could in principle be 49# ported to 32-bit as well. ) 50# 51config X86 52 def_bool y 53 # 54 # Note: keep this list sorted alphabetically 55 # 56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 58 select ARCH_32BIT_OFF_T if X86_32 59 select ARCH_CLOCKSOURCE_INIT 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 61 select ARCH_HAS_DEBUG_VIRTUAL 62 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 63 select ARCH_HAS_DEVMEM_IS_ALLOWED 64 select ARCH_HAS_EARLY_DEBUG if KGDB 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 74 select ARCH_HAS_PMEM_API if X86_64 75 select ARCH_HAS_PTE_DEVMAP if X86_64 76 select ARCH_HAS_PTE_SPECIAL 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 79 select ARCH_HAS_SET_MEMORY 80 select ARCH_HAS_SET_DIRECT_MAP 81 select ARCH_HAS_STRICT_KERNEL_RWX 82 select ARCH_HAS_STRICT_MODULE_RWX 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84 select ARCH_HAS_SYSCALL_WRAPPER 85 select ARCH_HAS_UBSAN_SANITIZE_ALL 86 select ARCH_HAS_DEBUG_WX 87 select ARCH_HAVE_NMI_SAFE_CMPXCHG 88 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 89 select ARCH_MIGHT_HAVE_PC_PARPORT 90 select ARCH_MIGHT_HAVE_PC_SERIO 91 select ARCH_STACKWALK 92 select ARCH_SUPPORTS_ACPI 93 select ARCH_SUPPORTS_ATOMIC_RMW 94 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 95 select ARCH_USE_BUILTIN_BSWAP 96 select ARCH_USE_QUEUED_RWLOCKS 97 select ARCH_USE_QUEUED_SPINLOCKS 98 select ARCH_USE_SYM_ANNOTATIONS 99 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 100 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 101 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 102 select ARCH_WANT_HUGE_PMD_SHARE 103 select ARCH_WANTS_THP_SWAP if X86_64 104 select BUILDTIME_TABLE_SORT 105 select CLKEVT_I8253 106 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 107 select CLOCKSOURCE_WATCHDOG 108 select DCACHE_WORD_ACCESS 109 select EDAC_ATOMIC_SCRUB 110 select EDAC_SUPPORT 111 select GENERIC_CLOCKEVENTS 112 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 113 select GENERIC_CLOCKEVENTS_MIN_ADJUST 114 select GENERIC_CMOS_UPDATE 115 select GENERIC_CPU_AUTOPROBE 116 select GENERIC_CPU_VULNERABILITIES 117 select GENERIC_EARLY_IOREMAP 118 select GENERIC_ENTRY 119 select GENERIC_FIND_FIRST_BIT 120 select GENERIC_IOMAP 121 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 122 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 123 select GENERIC_IRQ_MIGRATION if SMP 124 select GENERIC_IRQ_PROBE 125 select GENERIC_IRQ_RESERVATION_MODE 126 select GENERIC_IRQ_SHOW 127 select GENERIC_PENDING_IRQ if SMP 128 select GENERIC_PTDUMP 129 select GENERIC_SMP_IDLE_THREAD 130 select GENERIC_STRNCPY_FROM_USER 131 select GENERIC_STRNLEN_USER 132 select GENERIC_TIME_VSYSCALL 133 select GENERIC_GETTIMEOFDAY 134 select GENERIC_VDSO_TIME_NS 135 select GUP_GET_PTE_LOW_HIGH if X86_PAE 136 select HARDIRQS_SW_RESEND 137 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 138 select HAVE_ACPI_APEI if ACPI 139 select HAVE_ACPI_APEI_NMI if ACPI 140 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 141 select HAVE_ARCH_AUDITSYSCALL 142 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 143 select HAVE_ARCH_JUMP_LABEL 144 select HAVE_ARCH_JUMP_LABEL_RELATIVE 145 select HAVE_ARCH_KASAN if X86_64 146 select HAVE_ARCH_KASAN_VMALLOC if X86_64 147 select HAVE_ARCH_KGDB 148 select HAVE_ARCH_MMAP_RND_BITS if MMU 149 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 150 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 151 select HAVE_ARCH_PREL32_RELOCATIONS 152 select HAVE_ARCH_SECCOMP_FILTER 153 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 154 select HAVE_ARCH_STACKLEAK 155 select HAVE_ARCH_TRACEHOOK 156 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 157 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 158 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 159 select HAVE_ARCH_VMAP_STACK if X86_64 160 select HAVE_ARCH_WITHIN_STACK_FRAMES 161 select HAVE_ASM_MODVERSIONS 162 select HAVE_CMPXCHG_DOUBLE 163 select HAVE_CMPXCHG_LOCAL 164 select HAVE_CONTEXT_TRACKING if X86_64 165 select HAVE_C_RECORDMCOUNT 166 select HAVE_DEBUG_KMEMLEAK 167 select HAVE_DMA_CONTIGUOUS 168 select HAVE_DYNAMIC_FTRACE 169 select HAVE_DYNAMIC_FTRACE_WITH_REGS 170 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 171 select HAVE_EBPF_JIT 172 select HAVE_EFFICIENT_UNALIGNED_ACCESS 173 select HAVE_EISA 174 select HAVE_EXIT_THREAD 175 select HAVE_FAST_GUP 176 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 177 select HAVE_FTRACE_MCOUNT_RECORD 178 select HAVE_FUNCTION_GRAPH_TRACER 179 select HAVE_FUNCTION_TRACER 180 select HAVE_GCC_PLUGINS 181 select HAVE_HW_BREAKPOINT 182 select HAVE_IDE 183 select HAVE_IOREMAP_PROT 184 select HAVE_IRQ_TIME_ACCOUNTING 185 select HAVE_KERNEL_BZIP2 186 select HAVE_KERNEL_GZIP 187 select HAVE_KERNEL_LZ4 188 select HAVE_KERNEL_LZMA 189 select HAVE_KERNEL_LZO 190 select HAVE_KERNEL_XZ 191 select HAVE_KERNEL_ZSTD 192 select HAVE_KPROBES 193 select HAVE_KPROBES_ON_FTRACE 194 select HAVE_FUNCTION_ERROR_INJECTION 195 select HAVE_KRETPROBES 196 select HAVE_KVM 197 select HAVE_LIVEPATCH if X86_64 198 select HAVE_MIXED_BREAKPOINTS_REGS 199 select HAVE_MOD_ARCH_SPECIFIC 200 select HAVE_MOVE_PMD 201 select HAVE_NMI 202 select HAVE_OPROFILE 203 select HAVE_OPTPROBES 204 select HAVE_PCSPKR_PLATFORM 205 select HAVE_PERF_EVENTS 206 select HAVE_PERF_EVENTS_NMI 207 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 208 select HAVE_PCI 209 select HAVE_PERF_REGS 210 select HAVE_PERF_USER_STACK_DUMP 211 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 212 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 213 select HAVE_REGS_AND_STACK_ACCESS_API 214 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 215 select HAVE_FUNCTION_ARG_ACCESS_API 216 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 217 select HAVE_STACK_VALIDATION if X86_64 218 select HAVE_RSEQ 219 select HAVE_SYSCALL_TRACEPOINTS 220 select HAVE_UNSTABLE_SCHED_CLOCK 221 select HAVE_USER_RETURN_NOTIFIER 222 select HAVE_GENERIC_VDSO 223 select HOTPLUG_SMT if SMP 224 select IRQ_FORCED_THREADING 225 select NEED_SG_DMA_LENGTH 226 select PCI_DOMAINS if PCI 227 select PCI_LOCKLESS_CONFIG if PCI 228 select PERF_EVENTS 229 select RTC_LIB 230 select RTC_MC146818_LIB 231 select SPARSE_IRQ 232 select SRCU 233 select SYSCTL_EXCEPTION_TRACE 234 select THREAD_INFO_IN_TASK 235 select USER_STACKTRACE_SUPPORT 236 select VIRT_TO_BUS 237 select HAVE_ARCH_KCSAN if X86_64 238 select X86_FEATURE_NAMES if PROC_FS 239 select PROC_PID_ARCH_STATUS if PROC_FS 240 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 241 242config INSTRUCTION_DECODER 243 def_bool y 244 depends on KPROBES || PERF_EVENTS || UPROBES 245 246config OUTPUT_FORMAT 247 string 248 default "elf32-i386" if X86_32 249 default "elf64-x86-64" if X86_64 250 251config LOCKDEP_SUPPORT 252 def_bool y 253 254config STACKTRACE_SUPPORT 255 def_bool y 256 257config MMU 258 def_bool y 259 260config ARCH_MMAP_RND_BITS_MIN 261 default 28 if 64BIT 262 default 8 263 264config ARCH_MMAP_RND_BITS_MAX 265 default 32 if 64BIT 266 default 16 267 268config ARCH_MMAP_RND_COMPAT_BITS_MIN 269 default 8 270 271config ARCH_MMAP_RND_COMPAT_BITS_MAX 272 default 16 273 274config SBUS 275 bool 276 277config GENERIC_ISA_DMA 278 def_bool y 279 depends on ISA_DMA_API 280 281config GENERIC_BUG 282 def_bool y 283 depends on BUG 284 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 285 286config GENERIC_BUG_RELATIVE_POINTERS 287 bool 288 289config ARCH_MAY_HAVE_PC_FDC 290 def_bool y 291 depends on ISA_DMA_API 292 293config GENERIC_CALIBRATE_DELAY 294 def_bool y 295 296config ARCH_HAS_CPU_RELAX 297 def_bool y 298 299config ARCH_HAS_CACHE_LINE_SIZE 300 def_bool y 301 302config ARCH_HAS_FILTER_PGPROT 303 def_bool y 304 305config HAVE_SETUP_PER_CPU_AREA 306 def_bool y 307 308config NEED_PER_CPU_EMBED_FIRST_CHUNK 309 def_bool y 310 311config NEED_PER_CPU_PAGE_FIRST_CHUNK 312 def_bool y 313 314config ARCH_HIBERNATION_POSSIBLE 315 def_bool y 316 317config ARCH_SUSPEND_POSSIBLE 318 def_bool y 319 320config ARCH_WANT_GENERAL_HUGETLB 321 def_bool y 322 323config ZONE_DMA32 324 def_bool y if X86_64 325 326config AUDIT_ARCH 327 def_bool y if X86_64 328 329config ARCH_SUPPORTS_DEBUG_PAGEALLOC 330 def_bool y 331 332config KASAN_SHADOW_OFFSET 333 hex 334 depends on KASAN 335 default 0xdffffc0000000000 336 337config HAVE_INTEL_TXT 338 def_bool y 339 depends on INTEL_IOMMU && ACPI 340 341config X86_32_SMP 342 def_bool y 343 depends on X86_32 && SMP 344 345config X86_64_SMP 346 def_bool y 347 depends on X86_64 && SMP 348 349config X86_32_LAZY_GS 350 def_bool y 351 depends on X86_32 && !STACKPROTECTOR 352 353config ARCH_SUPPORTS_UPROBES 354 def_bool y 355 356config FIX_EARLYCON_MEM 357 def_bool y 358 359config DYNAMIC_PHYSICAL_MASK 360 bool 361 362config PGTABLE_LEVELS 363 int 364 default 5 if X86_5LEVEL 365 default 4 if X86_64 366 default 3 if X86_PAE 367 default 2 368 369config CC_HAS_SANE_STACKPROTECTOR 370 bool 371 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 372 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 373 help 374 We have to make sure stack protector is unconditionally disabled if 375 the compiler produces broken code. 376 377menu "Processor type and features" 378 379config ZONE_DMA 380 bool "DMA memory allocation support" if EXPERT 381 default y 382 help 383 DMA memory allocation support allows devices with less than 32-bit 384 addressing to allocate within the first 16MB of address space. 385 Disable if no such devices will be used. 386 387 If unsure, say Y. 388 389config SMP 390 bool "Symmetric multi-processing support" 391 help 392 This enables support for systems with more than one CPU. If you have 393 a system with only one CPU, say N. If you have a system with more 394 than one CPU, say Y. 395 396 If you say N here, the kernel will run on uni- and multiprocessor 397 machines, but will use only one CPU of a multiprocessor machine. If 398 you say Y here, the kernel will run on many, but not all, 399 uniprocessor machines. On a uniprocessor machine, the kernel 400 will run faster if you say N here. 401 402 Note that if you say Y here and choose architecture "586" or 403 "Pentium" under "Processor family", the kernel will not work on 486 404 architectures. Similarly, multiprocessor kernels for the "PPro" 405 architecture may not work on all Pentium based boards. 406 407 People using multiprocessor machines who say Y here should also say 408 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 409 Management" code will be disabled if you say Y here. 410 411 See also <file:Documentation/x86/i386/IO-APIC.rst>, 412 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 413 <http://www.tldp.org/docs.html#howto>. 414 415 If you don't know what to do here, say N. 416 417config X86_FEATURE_NAMES 418 bool "Processor feature human-readable names" if EMBEDDED 419 default y 420 help 421 This option compiles in a table of x86 feature bits and corresponding 422 names. This is required to support /proc/cpuinfo and a few kernel 423 messages. You can disable this to save space, at the expense of 424 making those few kernel messages show numeric feature bits instead. 425 426 If in doubt, say Y. 427 428config X86_X2APIC 429 bool "Support x2apic" 430 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 431 help 432 This enables x2apic support on CPUs that have this feature. 433 434 This allows 32-bit apic IDs (so it can support very large systems), 435 and accesses the local apic via MSRs not via mmio. 436 437 If you don't know what to do here, say N. 438 439config X86_MPPARSE 440 bool "Enable MPS table" if ACPI || SFI 441 default y 442 depends on X86_LOCAL_APIC 443 help 444 For old smp systems that do not have proper acpi support. Newer systems 445 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 446 447config GOLDFISH 448 def_bool y 449 depends on X86_GOLDFISH 450 451config RETPOLINE 452 bool "Avoid speculative indirect branches in kernel" 453 default y 454 select STACK_VALIDATION if HAVE_STACK_VALIDATION 455 help 456 Compile kernel with the retpoline compiler options to guard against 457 kernel-to-user data leaks by avoiding speculative indirect 458 branches. Requires a compiler with -mindirect-branch=thunk-extern 459 support for full protection. The kernel may run slower. 460 461config X86_CPU_RESCTRL 462 bool "x86 CPU resource control support" 463 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 464 select KERNFS 465 select PROC_CPU_RESCTRL if PROC_FS 466 help 467 Enable x86 CPU resource control support. 468 469 Provide support for the allocation and monitoring of system resources 470 usage by the CPU. 471 472 Intel calls this Intel Resource Director Technology 473 (Intel(R) RDT). More information about RDT can be found in the 474 Intel x86 Architecture Software Developer Manual. 475 476 AMD calls this AMD Platform Quality of Service (AMD QoS). 477 More information about AMD QoS can be found in the AMD64 Technology 478 Platform Quality of Service Extensions manual. 479 480 Say N if unsure. 481 482if X86_32 483config X86_BIGSMP 484 bool "Support for big SMP systems with more than 8 CPUs" 485 depends on SMP 486 help 487 This option is needed for the systems that have more than 8 CPUs. 488 489config X86_EXTENDED_PLATFORM 490 bool "Support for extended (non-PC) x86 platforms" 491 default y 492 help 493 If you disable this option then the kernel will only support 494 standard PC platforms. (which covers the vast majority of 495 systems out there.) 496 497 If you enable this option then you'll be able to select support 498 for the following (non-PC) 32 bit x86 platforms: 499 Goldfish (Android emulator) 500 AMD Elan 501 RDC R-321x SoC 502 SGI 320/540 (Visual Workstation) 503 STA2X11-based (e.g. Northville) 504 Moorestown MID devices 505 506 If you have one of these systems, or if you want to build a 507 generic distribution kernel, say Y here - otherwise say N. 508endif 509 510if X86_64 511config X86_EXTENDED_PLATFORM 512 bool "Support for extended (non-PC) x86 platforms" 513 default y 514 help 515 If you disable this option then the kernel will only support 516 standard PC platforms. (which covers the vast majority of 517 systems out there.) 518 519 If you enable this option then you'll be able to select support 520 for the following (non-PC) 64 bit x86 platforms: 521 Numascale NumaChip 522 ScaleMP vSMP 523 SGI Ultraviolet 524 525 If you have one of these systems, or if you want to build a 526 generic distribution kernel, say Y here - otherwise say N. 527endif 528# This is an alphabetically sorted list of 64 bit extended platforms 529# Please maintain the alphabetic order if and when there are additions 530config X86_NUMACHIP 531 bool "Numascale NumaChip" 532 depends on X86_64 533 depends on X86_EXTENDED_PLATFORM 534 depends on NUMA 535 depends on SMP 536 depends on X86_X2APIC 537 depends on PCI_MMCONFIG 538 help 539 Adds support for Numascale NumaChip large-SMP systems. Needed to 540 enable more than ~168 cores. 541 If you don't have one of these, you should say N here. 542 543config X86_VSMP 544 bool "ScaleMP vSMP" 545 select HYPERVISOR_GUEST 546 select PARAVIRT 547 depends on X86_64 && PCI 548 depends on X86_EXTENDED_PLATFORM 549 depends on SMP 550 help 551 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 552 supposed to run on these EM64T-based machines. Only choose this option 553 if you have one of these machines. 554 555config X86_UV 556 bool "SGI Ultraviolet" 557 depends on X86_64 558 depends on X86_EXTENDED_PLATFORM 559 depends on NUMA 560 depends on EFI 561 depends on X86_X2APIC 562 depends on PCI 563 help 564 This option is needed in order to support SGI Ultraviolet systems. 565 If you don't have one of these, you should say N here. 566 567# Following is an alphabetically sorted list of 32 bit extended platforms 568# Please maintain the alphabetic order if and when there are additions 569 570config X86_GOLDFISH 571 bool "Goldfish (Virtual Platform)" 572 depends on X86_EXTENDED_PLATFORM 573 help 574 Enable support for the Goldfish virtual platform used primarily 575 for Android development. Unless you are building for the Android 576 Goldfish emulator say N here. 577 578config X86_INTEL_CE 579 bool "CE4100 TV platform" 580 depends on PCI 581 depends on PCI_GODIRECT 582 depends on X86_IO_APIC 583 depends on X86_32 584 depends on X86_EXTENDED_PLATFORM 585 select X86_REBOOTFIXUPS 586 select OF 587 select OF_EARLY_FLATTREE 588 help 589 Select for the Intel CE media processor (CE4100) SOC. 590 This option compiles in support for the CE4100 SOC for settop 591 boxes and media devices. 592 593config X86_INTEL_MID 594 bool "Intel MID platform support" 595 depends on X86_EXTENDED_PLATFORM 596 depends on X86_PLATFORM_DEVICES 597 depends on PCI 598 depends on X86_64 || (PCI_GOANY && X86_32) 599 depends on X86_IO_APIC 600 select SFI 601 select I2C 602 select DW_APB_TIMER 603 select APB_TIMER 604 select INTEL_SCU_PCI 605 select MFD_INTEL_MSIC 606 help 607 Select to build a kernel capable of supporting Intel MID (Mobile 608 Internet Device) platform systems which do not have the PCI legacy 609 interfaces. If you are building for a PC class system say N here. 610 611 Intel MID platforms are based on an Intel processor and chipset which 612 consume less power than most of the x86 derivatives. 613 614config X86_INTEL_QUARK 615 bool "Intel Quark platform support" 616 depends on X86_32 617 depends on X86_EXTENDED_PLATFORM 618 depends on X86_PLATFORM_DEVICES 619 depends on X86_TSC 620 depends on PCI 621 depends on PCI_GOANY 622 depends on X86_IO_APIC 623 select IOSF_MBI 624 select INTEL_IMR 625 select COMMON_CLK 626 help 627 Select to include support for Quark X1000 SoC. 628 Say Y here if you have a Quark based system such as the Arduino 629 compatible Intel Galileo. 630 631config X86_INTEL_LPSS 632 bool "Intel Low Power Subsystem Support" 633 depends on X86 && ACPI && PCI 634 select COMMON_CLK 635 select PINCTRL 636 select IOSF_MBI 637 help 638 Select to build support for Intel Low Power Subsystem such as 639 found on Intel Lynxpoint PCH. Selecting this option enables 640 things like clock tree (common clock framework) and pincontrol 641 which are needed by the LPSS peripheral drivers. 642 643config X86_AMD_PLATFORM_DEVICE 644 bool "AMD ACPI2Platform devices support" 645 depends on ACPI 646 select COMMON_CLK 647 select PINCTRL 648 help 649 Select to interpret AMD specific ACPI device to platform device 650 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 651 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 652 implemented under PINCTRL subsystem. 653 654config IOSF_MBI 655 tristate "Intel SoC IOSF Sideband support for SoC platforms" 656 depends on PCI 657 help 658 This option enables sideband register access support for Intel SoC 659 platforms. On these platforms the IOSF sideband is used in lieu of 660 MSR's for some register accesses, mostly but not limited to thermal 661 and power. Drivers may query the availability of this device to 662 determine if they need the sideband in order to work on these 663 platforms. The sideband is available on the following SoC products. 664 This list is not meant to be exclusive. 665 - BayTrail 666 - Braswell 667 - Quark 668 669 You should say Y if you are running a kernel on one of these SoC's. 670 671config IOSF_MBI_DEBUG 672 bool "Enable IOSF sideband access through debugfs" 673 depends on IOSF_MBI && DEBUG_FS 674 help 675 Select this option to expose the IOSF sideband access registers (MCR, 676 MDR, MCRX) through debugfs to write and read register information from 677 different units on the SoC. This is most useful for obtaining device 678 state information for debug and analysis. As this is a general access 679 mechanism, users of this option would have specific knowledge of the 680 device they want to access. 681 682 If you don't require the option or are in doubt, say N. 683 684config X86_RDC321X 685 bool "RDC R-321x SoC" 686 depends on X86_32 687 depends on X86_EXTENDED_PLATFORM 688 select M486 689 select X86_REBOOTFIXUPS 690 help 691 This option is needed for RDC R-321x system-on-chip, also known 692 as R-8610-(G). 693 If you don't have one of these chips, you should say N here. 694 695config X86_32_NON_STANDARD 696 bool "Support non-standard 32-bit SMP architectures" 697 depends on X86_32 && SMP 698 depends on X86_EXTENDED_PLATFORM 699 help 700 This option compiles in the bigsmp and STA2X11 default 701 subarchitectures. It is intended for a generic binary 702 kernel. If you select them all, kernel will probe it one by 703 one and will fallback to default. 704 705# Alphabetically sorted list of Non standard 32 bit platforms 706 707config X86_SUPPORTS_MEMORY_FAILURE 708 def_bool y 709 # MCE code calls memory_failure(): 710 depends on X86_MCE 711 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 712 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 713 depends on X86_64 || !SPARSEMEM 714 select ARCH_SUPPORTS_MEMORY_FAILURE 715 716config STA2X11 717 bool "STA2X11 Companion Chip Support" 718 depends on X86_32_NON_STANDARD && PCI 719 select SWIOTLB 720 select MFD_STA2X11 721 select GPIOLIB 722 help 723 This adds support for boards based on the STA2X11 IO-Hub, 724 a.k.a. "ConneXt". The chip is used in place of the standard 725 PC chipset, so all "standard" peripherals are missing. If this 726 option is selected the kernel will still be able to boot on 727 standard PC machines. 728 729config X86_32_IRIS 730 tristate "Eurobraille/Iris poweroff module" 731 depends on X86_32 732 help 733 The Iris machines from EuroBraille do not have APM or ACPI support 734 to shut themselves down properly. A special I/O sequence is 735 needed to do so, which is what this module does at 736 kernel shutdown. 737 738 This is only for Iris machines from EuroBraille. 739 740 If unused, say N. 741 742config SCHED_OMIT_FRAME_POINTER 743 def_bool y 744 prompt "Single-depth WCHAN output" 745 depends on X86 746 help 747 Calculate simpler /proc/<PID>/wchan values. If this option 748 is disabled then wchan values will recurse back to the 749 caller function. This provides more accurate wchan values, 750 at the expense of slightly more scheduling overhead. 751 752 If in doubt, say "Y". 753 754menuconfig HYPERVISOR_GUEST 755 bool "Linux guest support" 756 help 757 Say Y here to enable options for running Linux under various hyper- 758 visors. This option enables basic hypervisor detection and platform 759 setup. 760 761 If you say N, all options in this submenu will be skipped and 762 disabled, and Linux guest support won't be built in. 763 764if HYPERVISOR_GUEST 765 766config PARAVIRT 767 bool "Enable paravirtualization code" 768 help 769 This changes the kernel so it can modify itself when it is run 770 under a hypervisor, potentially improving performance significantly 771 over full virtualization. However, when run without a hypervisor 772 the kernel is theoretically slower and slightly larger. 773 774config PARAVIRT_XXL 775 bool 776 777config PARAVIRT_DEBUG 778 bool "paravirt-ops debugging" 779 depends on PARAVIRT && DEBUG_KERNEL 780 help 781 Enable to debug paravirt_ops internals. Specifically, BUG if 782 a paravirt_op is missing when it is called. 783 784config PARAVIRT_SPINLOCKS 785 bool "Paravirtualization layer for spinlocks" 786 depends on PARAVIRT && SMP 787 help 788 Paravirtualized spinlocks allow a pvops backend to replace the 789 spinlock implementation with something virtualization-friendly 790 (for example, block the virtual CPU rather than spinning). 791 792 It has a minimal impact on native kernels and gives a nice performance 793 benefit on paravirtualized KVM / Xen kernels. 794 795 If you are unsure how to answer this question, answer Y. 796 797config X86_HV_CALLBACK_VECTOR 798 def_bool n 799 800source "arch/x86/xen/Kconfig" 801 802config KVM_GUEST 803 bool "KVM Guest support (including kvmclock)" 804 depends on PARAVIRT 805 select PARAVIRT_CLOCK 806 select ARCH_CPUIDLE_HALTPOLL 807 select X86_HV_CALLBACK_VECTOR 808 default y 809 help 810 This option enables various optimizations for running under the KVM 811 hypervisor. It includes a paravirtualized clock, so that instead 812 of relying on a PIT (or probably other) emulation by the 813 underlying device model, the host provides the guest with 814 timing infrastructure such as time of day, and system time 815 816config ARCH_CPUIDLE_HALTPOLL 817 def_bool n 818 prompt "Disable host haltpoll when loading haltpoll driver" 819 help 820 If virtualized under KVM, disable host haltpoll. 821 822config PVH 823 bool "Support for running PVH guests" 824 help 825 This option enables the PVH entry point for guest virtual machines 826 as specified in the x86/HVM direct boot ABI. 827 828config PARAVIRT_TIME_ACCOUNTING 829 bool "Paravirtual steal time accounting" 830 depends on PARAVIRT 831 help 832 Select this option to enable fine granularity task steal time 833 accounting. Time spent executing other tasks in parallel with 834 the current vCPU is discounted from the vCPU power. To account for 835 that, there can be a small performance impact. 836 837 If in doubt, say N here. 838 839config PARAVIRT_CLOCK 840 bool 841 842config JAILHOUSE_GUEST 843 bool "Jailhouse non-root cell support" 844 depends on X86_64 && PCI 845 select X86_PM_TIMER 846 help 847 This option allows to run Linux as guest in a Jailhouse non-root 848 cell. You can leave this option disabled if you only want to start 849 Jailhouse and run Linux afterwards in the root cell. 850 851config ACRN_GUEST 852 bool "ACRN Guest support" 853 depends on X86_64 854 select X86_HV_CALLBACK_VECTOR 855 help 856 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 857 a flexible, lightweight reference open-source hypervisor, built with 858 real-time and safety-criticality in mind. It is built for embedded 859 IOT with small footprint and real-time features. More details can be 860 found in https://projectacrn.org/. 861 862endif #HYPERVISOR_GUEST 863 864source "arch/x86/Kconfig.cpu" 865 866config HPET_TIMER 867 def_bool X86_64 868 prompt "HPET Timer Support" if X86_32 869 help 870 Use the IA-PC HPET (High Precision Event Timer) to manage 871 time in preference to the PIT and RTC, if a HPET is 872 present. 873 HPET is the next generation timer replacing legacy 8254s. 874 The HPET provides a stable time base on SMP 875 systems, unlike the TSC, but it is more expensive to access, 876 as it is off-chip. The interface used is documented 877 in the HPET spec, revision 1. 878 879 You can safely choose Y here. However, HPET will only be 880 activated if the platform and the BIOS support this feature. 881 Otherwise the 8254 will be used for timing services. 882 883 Choose N to continue using the legacy 8254 timer. 884 885config HPET_EMULATE_RTC 886 def_bool y 887 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 888 889config APB_TIMER 890 def_bool y if X86_INTEL_MID 891 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 892 select DW_APB_TIMER 893 depends on X86_INTEL_MID && SFI 894 help 895 APB timer is the replacement for 8254, HPET on X86 MID platforms. 896 The APBT provides a stable time base on SMP 897 systems, unlike the TSC, but it is more expensive to access, 898 as it is off-chip. APB timers are always running regardless of CPU 899 C states, they are used as per CPU clockevent device when possible. 900 901# Mark as expert because too many people got it wrong. 902# The code disables itself when not needed. 903config DMI 904 default y 905 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 906 bool "Enable DMI scanning" if EXPERT 907 help 908 Enabled scanning of DMI to identify machine quirks. Say Y 909 here unless you have verified that your setup is not 910 affected by entries in the DMI blacklist. Required by PNP 911 BIOS code. 912 913config GART_IOMMU 914 bool "Old AMD GART IOMMU support" 915 select DMA_OPS 916 select IOMMU_HELPER 917 select SWIOTLB 918 depends on X86_64 && PCI && AMD_NB 919 help 920 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 921 GART based hardware IOMMUs. 922 923 The GART supports full DMA access for devices with 32-bit access 924 limitations, on systems with more than 3 GB. This is usually needed 925 for USB, sound, many IDE/SATA chipsets and some other devices. 926 927 Newer systems typically have a modern AMD IOMMU, supported via 928 the CONFIG_AMD_IOMMU=y config option. 929 930 In normal configurations this driver is only active when needed: 931 there's more than 3 GB of memory and the system contains a 932 32-bit limited device. 933 934 If unsure, say Y. 935 936config MAXSMP 937 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 938 depends on X86_64 && SMP && DEBUG_KERNEL 939 select CPUMASK_OFFSTACK 940 help 941 Enable maximum number of CPUS and NUMA Nodes for this architecture. 942 If unsure, say N. 943 944# 945# The maximum number of CPUs supported: 946# 947# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 948# and which can be configured interactively in the 949# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 950# 951# The ranges are different on 32-bit and 64-bit kernels, depending on 952# hardware capabilities and scalability features of the kernel. 953# 954# ( If MAXSMP is enabled we just use the highest possible value and disable 955# interactive configuration. ) 956# 957 958config NR_CPUS_RANGE_BEGIN 959 int 960 default NR_CPUS_RANGE_END if MAXSMP 961 default 1 if !SMP 962 default 2 963 964config NR_CPUS_RANGE_END 965 int 966 depends on X86_32 967 default 64 if SMP && X86_BIGSMP 968 default 8 if SMP && !X86_BIGSMP 969 default 1 if !SMP 970 971config NR_CPUS_RANGE_END 972 int 973 depends on X86_64 974 default 8192 if SMP && CPUMASK_OFFSTACK 975 default 512 if SMP && !CPUMASK_OFFSTACK 976 default 1 if !SMP 977 978config NR_CPUS_DEFAULT 979 int 980 depends on X86_32 981 default 32 if X86_BIGSMP 982 default 8 if SMP 983 default 1 if !SMP 984 985config NR_CPUS_DEFAULT 986 int 987 depends on X86_64 988 default 8192 if MAXSMP 989 default 64 if SMP 990 default 1 if !SMP 991 992config NR_CPUS 993 int "Maximum number of CPUs" if SMP && !MAXSMP 994 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 995 default NR_CPUS_DEFAULT 996 help 997 This allows you to specify the maximum number of CPUs which this 998 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 999 supported value is 8192, otherwise the maximum value is 512. The 1000 minimum value which makes sense is 2. 1001 1002 This is purely to save memory: each supported CPU adds about 8KB 1003 to the kernel image. 1004 1005config SCHED_SMT 1006 def_bool y if SMP 1007 1008config SCHED_MC 1009 def_bool y 1010 prompt "Multi-core scheduler support" 1011 depends on SMP 1012 help 1013 Multi-core scheduler support improves the CPU scheduler's decision 1014 making when dealing with multi-core CPU chips at a cost of slightly 1015 increased overhead in some places. If unsure say N here. 1016 1017config SCHED_MC_PRIO 1018 bool "CPU core priorities scheduler support" 1019 depends on SCHED_MC && CPU_SUP_INTEL 1020 select X86_INTEL_PSTATE 1021 select CPU_FREQ 1022 default y 1023 help 1024 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1025 core ordering determined at manufacturing time, which allows 1026 certain cores to reach higher turbo frequencies (when running 1027 single threaded workloads) than others. 1028 1029 Enabling this kernel feature teaches the scheduler about 1030 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1031 scheduler's CPU selection logic accordingly, so that higher 1032 overall system performance can be achieved. 1033 1034 This feature will have no effect on CPUs without this feature. 1035 1036 If unsure say Y here. 1037 1038config UP_LATE_INIT 1039 def_bool y 1040 depends on !SMP && X86_LOCAL_APIC 1041 1042config X86_UP_APIC 1043 bool "Local APIC support on uniprocessors" if !PCI_MSI 1044 default PCI_MSI 1045 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1046 help 1047 A local APIC (Advanced Programmable Interrupt Controller) is an 1048 integrated interrupt controller in the CPU. If you have a single-CPU 1049 system which has a processor with a local APIC, you can say Y here to 1050 enable and use it. If you say Y here even though your machine doesn't 1051 have a local APIC, then the kernel will still run with no slowdown at 1052 all. The local APIC supports CPU-generated self-interrupts (timer, 1053 performance counters), and the NMI watchdog which detects hard 1054 lockups. 1055 1056config X86_UP_IOAPIC 1057 bool "IO-APIC support on uniprocessors" 1058 depends on X86_UP_APIC 1059 help 1060 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1061 SMP-capable replacement for PC-style interrupt controllers. Most 1062 SMP systems and many recent uniprocessor systems have one. 1063 1064 If you have a single-CPU system with an IO-APIC, you can say Y here 1065 to use it. If you say Y here even though your machine doesn't have 1066 an IO-APIC, then the kernel will still run with no slowdown at all. 1067 1068config X86_LOCAL_APIC 1069 def_bool y 1070 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1071 select IRQ_DOMAIN_HIERARCHY 1072 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1073 1074config X86_IO_APIC 1075 def_bool y 1076 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1077 1078config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1079 bool "Reroute for broken boot IRQs" 1080 depends on X86_IO_APIC 1081 help 1082 This option enables a workaround that fixes a source of 1083 spurious interrupts. This is recommended when threaded 1084 interrupt handling is used on systems where the generation of 1085 superfluous "boot interrupts" cannot be disabled. 1086 1087 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1088 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1089 kernel does during interrupt handling). On chipsets where this 1090 boot IRQ generation cannot be disabled, this workaround keeps 1091 the original IRQ line masked so that only the equivalent "boot 1092 IRQ" is delivered to the CPUs. The workaround also tells the 1093 kernel to set up the IRQ handler on the boot IRQ line. In this 1094 way only one interrupt is delivered to the kernel. Otherwise 1095 the spurious second interrupt may cause the kernel to bring 1096 down (vital) interrupt lines. 1097 1098 Only affects "broken" chipsets. Interrupt sharing may be 1099 increased on these systems. 1100 1101config X86_MCE 1102 bool "Machine Check / overheating reporting" 1103 select GENERIC_ALLOCATOR 1104 default y 1105 help 1106 Machine Check support allows the processor to notify the 1107 kernel if it detects a problem (e.g. overheating, data corruption). 1108 The action the kernel takes depends on the severity of the problem, 1109 ranging from warning messages to halting the machine. 1110 1111config X86_MCELOG_LEGACY 1112 bool "Support for deprecated /dev/mcelog character device" 1113 depends on X86_MCE 1114 help 1115 Enable support for /dev/mcelog which is needed by the old mcelog 1116 userspace logging daemon. Consider switching to the new generation 1117 rasdaemon solution. 1118 1119config X86_MCE_INTEL 1120 def_bool y 1121 prompt "Intel MCE features" 1122 depends on X86_MCE && X86_LOCAL_APIC 1123 help 1124 Additional support for intel specific MCE features such as 1125 the thermal monitor. 1126 1127config X86_MCE_AMD 1128 def_bool y 1129 prompt "AMD MCE features" 1130 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1131 help 1132 Additional support for AMD specific MCE features such as 1133 the DRAM Error Threshold. 1134 1135config X86_ANCIENT_MCE 1136 bool "Support for old Pentium 5 / WinChip machine checks" 1137 depends on X86_32 && X86_MCE 1138 help 1139 Include support for machine check handling on old Pentium 5 or WinChip 1140 systems. These typically need to be enabled explicitly on the command 1141 line. 1142 1143config X86_MCE_THRESHOLD 1144 depends on X86_MCE_AMD || X86_MCE_INTEL 1145 def_bool y 1146 1147config X86_MCE_INJECT 1148 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1149 tristate "Machine check injector support" 1150 help 1151 Provide support for injecting machine checks for testing purposes. 1152 If you don't know what a machine check is and you don't do kernel 1153 QA it is safe to say n. 1154 1155config X86_THERMAL_VECTOR 1156 def_bool y 1157 depends on X86_MCE_INTEL 1158 1159source "arch/x86/events/Kconfig" 1160 1161config X86_LEGACY_VM86 1162 bool "Legacy VM86 support" 1163 depends on X86_32 1164 help 1165 This option allows user programs to put the CPU into V8086 1166 mode, which is an 80286-era approximation of 16-bit real mode. 1167 1168 Some very old versions of X and/or vbetool require this option 1169 for user mode setting. Similarly, DOSEMU will use it if 1170 available to accelerate real mode DOS programs. However, any 1171 recent version of DOSEMU, X, or vbetool should be fully 1172 functional even without kernel VM86 support, as they will all 1173 fall back to software emulation. Nevertheless, if you are using 1174 a 16-bit DOS program where 16-bit performance matters, vm86 1175 mode might be faster than emulation and you might want to 1176 enable this option. 1177 1178 Note that any app that works on a 64-bit kernel is unlikely to 1179 need this option, as 64-bit kernels don't, and can't, support 1180 V8086 mode. This option is also unrelated to 16-bit protected 1181 mode and is not needed to run most 16-bit programs under Wine. 1182 1183 Enabling this option increases the complexity of the kernel 1184 and slows down exception handling a tiny bit. 1185 1186 If unsure, say N here. 1187 1188config VM86 1189 bool 1190 default X86_LEGACY_VM86 1191 1192config X86_16BIT 1193 bool "Enable support for 16-bit segments" if EXPERT 1194 default y 1195 depends on MODIFY_LDT_SYSCALL 1196 help 1197 This option is required by programs like Wine to run 16-bit 1198 protected mode legacy code on x86 processors. Disabling 1199 this option saves about 300 bytes on i386, or around 6K text 1200 plus 16K runtime memory on x86-64, 1201 1202config X86_ESPFIX32 1203 def_bool y 1204 depends on X86_16BIT && X86_32 1205 1206config X86_ESPFIX64 1207 def_bool y 1208 depends on X86_16BIT && X86_64 1209 1210config X86_VSYSCALL_EMULATION 1211 bool "Enable vsyscall emulation" if EXPERT 1212 default y 1213 depends on X86_64 1214 help 1215 This enables emulation of the legacy vsyscall page. Disabling 1216 it is roughly equivalent to booting with vsyscall=none, except 1217 that it will also disable the helpful warning if a program 1218 tries to use a vsyscall. With this option set to N, offending 1219 programs will just segfault, citing addresses of the form 1220 0xffffffffff600?00. 1221 1222 This option is required by many programs built before 2013, and 1223 care should be used even with newer programs if set to N. 1224 1225 Disabling this option saves about 7K of kernel size and 1226 possibly 4K of additional runtime pagetable memory. 1227 1228config X86_IOPL_IOPERM 1229 bool "IOPERM and IOPL Emulation" 1230 default y 1231 help 1232 This enables the ioperm() and iopl() syscalls which are necessary 1233 for legacy applications. 1234 1235 Legacy IOPL support is an overbroad mechanism which allows user 1236 space aside of accessing all 65536 I/O ports also to disable 1237 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1238 capabilities and permission from potentially active security 1239 modules. 1240 1241 The emulation restricts the functionality of the syscall to 1242 only allowing the full range I/O port access, but prevents the 1243 ability to disable interrupts from user space which would be 1244 granted if the hardware IOPL mechanism would be used. 1245 1246config TOSHIBA 1247 tristate "Toshiba Laptop support" 1248 depends on X86_32 1249 help 1250 This adds a driver to safely access the System Management Mode of 1251 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1252 not work on models with a Phoenix BIOS. The System Management Mode 1253 is used to set the BIOS and power saving options on Toshiba portables. 1254 1255 For information on utilities to make use of this driver see the 1256 Toshiba Linux utilities web site at: 1257 <http://www.buzzard.org.uk/toshiba/>. 1258 1259 Say Y if you intend to run this kernel on a Toshiba portable. 1260 Say N otherwise. 1261 1262config I8K 1263 tristate "Dell i8k legacy laptop support" 1264 select HWMON 1265 select SENSORS_DELL_SMM 1266 help 1267 This option enables legacy /proc/i8k userspace interface in hwmon 1268 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1269 temperature and allows controlling fan speeds of Dell laptops via 1270 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1271 it reports also power and hotkey status. For fan speed control is 1272 needed userspace package i8kutils. 1273 1274 Say Y if you intend to run this kernel on old Dell laptops or want to 1275 use userspace package i8kutils. 1276 Say N otherwise. 1277 1278config X86_REBOOTFIXUPS 1279 bool "Enable X86 board specific fixups for reboot" 1280 depends on X86_32 1281 help 1282 This enables chipset and/or board specific fixups to be done 1283 in order to get reboot to work correctly. This is only needed on 1284 some combinations of hardware and BIOS. The symptom, for which 1285 this config is intended, is when reboot ends with a stalled/hung 1286 system. 1287 1288 Currently, the only fixup is for the Geode machines using 1289 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1290 1291 Say Y if you want to enable the fixup. Currently, it's safe to 1292 enable this option even if you don't need it. 1293 Say N otherwise. 1294 1295config MICROCODE 1296 bool "CPU microcode loading support" 1297 default y 1298 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1299 help 1300 If you say Y here, you will be able to update the microcode on 1301 Intel and AMD processors. The Intel support is for the IA32 family, 1302 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1303 AMD support is for families 0x10 and later. You will obviously need 1304 the actual microcode binary data itself which is not shipped with 1305 the Linux kernel. 1306 1307 The preferred method to load microcode from a detached initrd is described 1308 in Documentation/x86/microcode.rst. For that you need to enable 1309 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1310 initrd for microcode blobs. 1311 1312 In addition, you can build the microcode into the kernel. For that you 1313 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1314 config option. 1315 1316config MICROCODE_INTEL 1317 bool "Intel microcode loading support" 1318 depends on MICROCODE 1319 default MICROCODE 1320 help 1321 This options enables microcode patch loading support for Intel 1322 processors. 1323 1324 For the current Intel microcode data package go to 1325 <https://downloadcenter.intel.com> and search for 1326 'Linux Processor Microcode Data File'. 1327 1328config MICROCODE_AMD 1329 bool "AMD microcode loading support" 1330 depends on MICROCODE 1331 help 1332 If you select this option, microcode patch loading support for AMD 1333 processors will be enabled. 1334 1335config MICROCODE_OLD_INTERFACE 1336 bool "Ancient loading interface (DEPRECATED)" 1337 default n 1338 depends on MICROCODE 1339 help 1340 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1341 which was used by userspace tools like iucode_tool and microcode.ctl. 1342 It is inadequate because it runs too late to be able to properly 1343 load microcode on a machine and it needs special tools. Instead, you 1344 should've switched to the early loading method with the initrd or 1345 builtin microcode by now: Documentation/x86/microcode.rst 1346 1347config X86_MSR 1348 tristate "/dev/cpu/*/msr - Model-specific register support" 1349 help 1350 This device gives privileged processes access to the x86 1351 Model-Specific Registers (MSRs). It is a character device with 1352 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1353 MSR accesses are directed to a specific CPU on multi-processor 1354 systems. 1355 1356config X86_CPUID 1357 tristate "/dev/cpu/*/cpuid - CPU information support" 1358 help 1359 This device gives processes access to the x86 CPUID instruction to 1360 be executed on a specific processor. It is a character device 1361 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1362 /dev/cpu/31/cpuid. 1363 1364choice 1365 prompt "High Memory Support" 1366 default HIGHMEM4G 1367 depends on X86_32 1368 1369config NOHIGHMEM 1370 bool "off" 1371 help 1372 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1373 However, the address space of 32-bit x86 processors is only 4 1374 Gigabytes large. That means that, if you have a large amount of 1375 physical memory, not all of it can be "permanently mapped" by the 1376 kernel. The physical memory that's not permanently mapped is called 1377 "high memory". 1378 1379 If you are compiling a kernel which will never run on a machine with 1380 more than 1 Gigabyte total physical RAM, answer "off" here (default 1381 choice and suitable for most users). This will result in a "3GB/1GB" 1382 split: 3GB are mapped so that each process sees a 3GB virtual memory 1383 space and the remaining part of the 4GB virtual memory space is used 1384 by the kernel to permanently map as much physical memory as 1385 possible. 1386 1387 If the machine has between 1 and 4 Gigabytes physical RAM, then 1388 answer "4GB" here. 1389 1390 If more than 4 Gigabytes is used then answer "64GB" here. This 1391 selection turns Intel PAE (Physical Address Extension) mode on. 1392 PAE implements 3-level paging on IA32 processors. PAE is fully 1393 supported by Linux, PAE mode is implemented on all recent Intel 1394 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1395 then the kernel will not boot on CPUs that don't support PAE! 1396 1397 The actual amount of total physical memory will either be 1398 auto detected or can be forced by using a kernel command line option 1399 such as "mem=256M". (Try "man bootparam" or see the documentation of 1400 your boot loader (lilo or loadlin) about how to pass options to the 1401 kernel at boot time.) 1402 1403 If unsure, say "off". 1404 1405config HIGHMEM4G 1406 bool "4GB" 1407 help 1408 Select this if you have a 32-bit processor and between 1 and 4 1409 gigabytes of physical RAM. 1410 1411config HIGHMEM64G 1412 bool "64GB" 1413 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1414 select X86_PAE 1415 help 1416 Select this if you have a 32-bit processor and more than 4 1417 gigabytes of physical RAM. 1418 1419endchoice 1420 1421choice 1422 prompt "Memory split" if EXPERT 1423 default VMSPLIT_3G 1424 depends on X86_32 1425 help 1426 Select the desired split between kernel and user memory. 1427 1428 If the address range available to the kernel is less than the 1429 physical memory installed, the remaining memory will be available 1430 as "high memory". Accessing high memory is a little more costly 1431 than low memory, as it needs to be mapped into the kernel first. 1432 Note that increasing the kernel address space limits the range 1433 available to user programs, making the address space there 1434 tighter. Selecting anything other than the default 3G/1G split 1435 will also likely make your kernel incompatible with binary-only 1436 kernel modules. 1437 1438 If you are not absolutely sure what you are doing, leave this 1439 option alone! 1440 1441 config VMSPLIT_3G 1442 bool "3G/1G user/kernel split" 1443 config VMSPLIT_3G_OPT 1444 depends on !X86_PAE 1445 bool "3G/1G user/kernel split (for full 1G low memory)" 1446 config VMSPLIT_2G 1447 bool "2G/2G user/kernel split" 1448 config VMSPLIT_2G_OPT 1449 depends on !X86_PAE 1450 bool "2G/2G user/kernel split (for full 2G low memory)" 1451 config VMSPLIT_1G 1452 bool "1G/3G user/kernel split" 1453endchoice 1454 1455config PAGE_OFFSET 1456 hex 1457 default 0xB0000000 if VMSPLIT_3G_OPT 1458 default 0x80000000 if VMSPLIT_2G 1459 default 0x78000000 if VMSPLIT_2G_OPT 1460 default 0x40000000 if VMSPLIT_1G 1461 default 0xC0000000 1462 depends on X86_32 1463 1464config HIGHMEM 1465 def_bool y 1466 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1467 1468config X86_PAE 1469 bool "PAE (Physical Address Extension) Support" 1470 depends on X86_32 && !HIGHMEM4G 1471 select PHYS_ADDR_T_64BIT 1472 select SWIOTLB 1473 help 1474 PAE is required for NX support, and furthermore enables 1475 larger swapspace support for non-overcommit purposes. It 1476 has the cost of more pagetable lookup overhead, and also 1477 consumes more pagetable space per process. 1478 1479config X86_5LEVEL 1480 bool "Enable 5-level page tables support" 1481 default y 1482 select DYNAMIC_MEMORY_LAYOUT 1483 select SPARSEMEM_VMEMMAP 1484 depends on X86_64 1485 help 1486 5-level paging enables access to larger address space: 1487 upto 128 PiB of virtual address space and 4 PiB of 1488 physical address space. 1489 1490 It will be supported by future Intel CPUs. 1491 1492 A kernel with the option enabled can be booted on machines that 1493 support 4- or 5-level paging. 1494 1495 See Documentation/x86/x86_64/5level-paging.rst for more 1496 information. 1497 1498 Say N if unsure. 1499 1500config X86_DIRECT_GBPAGES 1501 def_bool y 1502 depends on X86_64 1503 help 1504 Certain kernel features effectively disable kernel 1505 linear 1 GB mappings (even if the CPU otherwise 1506 supports them), so don't confuse the user by printing 1507 that we have them enabled. 1508 1509config X86_CPA_STATISTICS 1510 bool "Enable statistic for Change Page Attribute" 1511 depends on DEBUG_FS 1512 help 1513 Expose statistics about the Change Page Attribute mechanism, which 1514 helps to determine the effectiveness of preserving large and huge 1515 page mappings when mapping protections are changed. 1516 1517config AMD_MEM_ENCRYPT 1518 bool "AMD Secure Memory Encryption (SME) support" 1519 depends on X86_64 && CPU_SUP_AMD 1520 select DMA_COHERENT_POOL 1521 select DYNAMIC_PHYSICAL_MASK 1522 select ARCH_USE_MEMREMAP_PROT 1523 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1524 help 1525 Say yes to enable support for the encryption of system memory. 1526 This requires an AMD processor that supports Secure Memory 1527 Encryption (SME). 1528 1529config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1530 bool "Activate AMD Secure Memory Encryption (SME) by default" 1531 default y 1532 depends on AMD_MEM_ENCRYPT 1533 help 1534 Say yes to have system memory encrypted by default if running on 1535 an AMD processor that supports Secure Memory Encryption (SME). 1536 1537 If set to Y, then the encryption of system memory can be 1538 deactivated with the mem_encrypt=off command line option. 1539 1540 If set to N, then the encryption of system memory can be 1541 activated with the mem_encrypt=on command line option. 1542 1543# Common NUMA Features 1544config NUMA 1545 bool "NUMA Memory Allocation and Scheduler Support" 1546 depends on SMP 1547 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1548 default y if X86_BIGSMP 1549 help 1550 Enable NUMA (Non-Uniform Memory Access) support. 1551 1552 The kernel will try to allocate memory used by a CPU on the 1553 local memory controller of the CPU and add some more 1554 NUMA awareness to the kernel. 1555 1556 For 64-bit this is recommended if the system is Intel Core i7 1557 (or later), AMD Opteron, or EM64T NUMA. 1558 1559 For 32-bit this is only needed if you boot a 32-bit 1560 kernel on a 64-bit NUMA platform. 1561 1562 Otherwise, you should say N. 1563 1564config AMD_NUMA 1565 def_bool y 1566 prompt "Old style AMD Opteron NUMA detection" 1567 depends on X86_64 && NUMA && PCI 1568 help 1569 Enable AMD NUMA node topology detection. You should say Y here if 1570 you have a multi processor AMD system. This uses an old method to 1571 read the NUMA configuration directly from the builtin Northbridge 1572 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1573 which also takes priority if both are compiled in. 1574 1575config X86_64_ACPI_NUMA 1576 def_bool y 1577 prompt "ACPI NUMA detection" 1578 depends on X86_64 && NUMA && ACPI && PCI 1579 select ACPI_NUMA 1580 help 1581 Enable ACPI SRAT based node topology detection. 1582 1583config NUMA_EMU 1584 bool "NUMA emulation" 1585 depends on NUMA 1586 help 1587 Enable NUMA emulation. A flat machine will be split 1588 into virtual nodes when booted with "numa=fake=N", where N is the 1589 number of nodes. This is only useful for debugging. 1590 1591config NODES_SHIFT 1592 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1593 range 1 10 1594 default "10" if MAXSMP 1595 default "6" if X86_64 1596 default "3" 1597 depends on NEED_MULTIPLE_NODES 1598 help 1599 Specify the maximum number of NUMA Nodes available on the target 1600 system. Increases memory reserved to accommodate various tables. 1601 1602config ARCH_FLATMEM_ENABLE 1603 def_bool y 1604 depends on X86_32 && !NUMA 1605 1606config ARCH_SPARSEMEM_ENABLE 1607 def_bool y 1608 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1609 select SPARSEMEM_STATIC if X86_32 1610 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1611 1612config ARCH_SPARSEMEM_DEFAULT 1613 def_bool X86_64 || (NUMA && X86_32) 1614 1615config ARCH_SELECT_MEMORY_MODEL 1616 def_bool y 1617 depends on ARCH_SPARSEMEM_ENABLE 1618 1619config ARCH_MEMORY_PROBE 1620 bool "Enable sysfs memory/probe interface" 1621 depends on X86_64 && MEMORY_HOTPLUG 1622 help 1623 This option enables a sysfs memory/probe interface for testing. 1624 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1625 If you are unsure how to answer this question, answer N. 1626 1627config ARCH_PROC_KCORE_TEXT 1628 def_bool y 1629 depends on X86_64 && PROC_KCORE 1630 1631config ILLEGAL_POINTER_VALUE 1632 hex 1633 default 0 if X86_32 1634 default 0xdead000000000000 if X86_64 1635 1636config X86_PMEM_LEGACY_DEVICE 1637 bool 1638 1639config X86_PMEM_LEGACY 1640 tristate "Support non-standard NVDIMMs and ADR protected memory" 1641 depends on PHYS_ADDR_T_64BIT 1642 depends on BLK_DEV 1643 select X86_PMEM_LEGACY_DEVICE 1644 select NUMA_KEEP_MEMINFO if NUMA 1645 select LIBNVDIMM 1646 help 1647 Treat memory marked using the non-standard e820 type of 12 as used 1648 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1649 The kernel will offer these regions to the 'pmem' driver so 1650 they can be used for persistent storage. 1651 1652 Say Y if unsure. 1653 1654config HIGHPTE 1655 bool "Allocate 3rd-level pagetables from highmem" 1656 depends on HIGHMEM 1657 help 1658 The VM uses one page table entry for each page of physical memory. 1659 For systems with a lot of RAM, this can be wasteful of precious 1660 low memory. Setting this option will put user-space page table 1661 entries in high memory. 1662 1663config X86_CHECK_BIOS_CORRUPTION 1664 bool "Check for low memory corruption" 1665 help 1666 Periodically check for memory corruption in low memory, which 1667 is suspected to be caused by BIOS. Even when enabled in the 1668 configuration, it is disabled at runtime. Enable it by 1669 setting "memory_corruption_check=1" on the kernel command 1670 line. By default it scans the low 64k of memory every 60 1671 seconds; see the memory_corruption_check_size and 1672 memory_corruption_check_period parameters in 1673 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1674 1675 When enabled with the default parameters, this option has 1676 almost no overhead, as it reserves a relatively small amount 1677 of memory and scans it infrequently. It both detects corruption 1678 and prevents it from affecting the running system. 1679 1680 It is, however, intended as a diagnostic tool; if repeatable 1681 BIOS-originated corruption always affects the same memory, 1682 you can use memmap= to prevent the kernel from using that 1683 memory. 1684 1685config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1686 bool "Set the default setting of memory_corruption_check" 1687 depends on X86_CHECK_BIOS_CORRUPTION 1688 default y 1689 help 1690 Set whether the default state of memory_corruption_check is 1691 on or off. 1692 1693config X86_RESERVE_LOW 1694 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1695 default 64 1696 range 4 640 1697 help 1698 Specify the amount of low memory to reserve for the BIOS. 1699 1700 The first page contains BIOS data structures that the kernel 1701 must not use, so that page must always be reserved. 1702 1703 By default we reserve the first 64K of physical RAM, as a 1704 number of BIOSes are known to corrupt that memory range 1705 during events such as suspend/resume or monitor cable 1706 insertion, so it must not be used by the kernel. 1707 1708 You can set this to 4 if you are absolutely sure that you 1709 trust the BIOS to get all its memory reservations and usages 1710 right. If you know your BIOS have problems beyond the 1711 default 64K area, you can set this to 640 to avoid using the 1712 entire low memory range. 1713 1714 If you have doubts about the BIOS (e.g. suspend/resume does 1715 not work or there's kernel crashes after certain hardware 1716 hotplug events) then you might want to enable 1717 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1718 typical corruption patterns. 1719 1720 Leave this to the default value of 64 if you are unsure. 1721 1722config MATH_EMULATION 1723 bool 1724 depends on MODIFY_LDT_SYSCALL 1725 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1726 help 1727 Linux can emulate a math coprocessor (used for floating point 1728 operations) if you don't have one. 486DX and Pentium processors have 1729 a math coprocessor built in, 486SX and 386 do not, unless you added 1730 a 487DX or 387, respectively. (The messages during boot time can 1731 give you some hints here ["man dmesg"].) Everyone needs either a 1732 coprocessor or this emulation. 1733 1734 If you don't have a math coprocessor, you need to say Y here; if you 1735 say Y here even though you have a coprocessor, the coprocessor will 1736 be used nevertheless. (This behavior can be changed with the kernel 1737 command line option "no387", which comes handy if your coprocessor 1738 is broken. Try "man bootparam" or see the documentation of your boot 1739 loader (lilo or loadlin) about how to pass options to the kernel at 1740 boot time.) This means that it is a good idea to say Y here if you 1741 intend to use this kernel on different machines. 1742 1743 More information about the internals of the Linux math coprocessor 1744 emulation can be found in <file:arch/x86/math-emu/README>. 1745 1746 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1747 kernel, it won't hurt. 1748 1749config MTRR 1750 def_bool y 1751 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1752 help 1753 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1754 the Memory Type Range Registers (MTRRs) may be used to control 1755 processor access to memory ranges. This is most useful if you have 1756 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1757 allows bus write transfers to be combined into a larger transfer 1758 before bursting over the PCI/AGP bus. This can increase performance 1759 of image write operations 2.5 times or more. Saying Y here creates a 1760 /proc/mtrr file which may be used to manipulate your processor's 1761 MTRRs. Typically the X server should use this. 1762 1763 This code has a reasonably generic interface so that similar 1764 control registers on other processors can be easily supported 1765 as well: 1766 1767 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1768 Registers (ARRs) which provide a similar functionality to MTRRs. For 1769 these, the ARRs are used to emulate the MTRRs. 1770 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1771 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1772 write-combining. All of these processors are supported by this code 1773 and it makes sense to say Y here if you have one of them. 1774 1775 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1776 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1777 can lead to all sorts of problems, so it's good to say Y here. 1778 1779 You can safely say Y even if your machine doesn't have MTRRs, you'll 1780 just add about 9 KB to your kernel. 1781 1782 See <file:Documentation/x86/mtrr.rst> for more information. 1783 1784config MTRR_SANITIZER 1785 def_bool y 1786 prompt "MTRR cleanup support" 1787 depends on MTRR 1788 help 1789 Convert MTRR layout from continuous to discrete, so X drivers can 1790 add writeback entries. 1791 1792 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1793 The largest mtrr entry size for a continuous block can be set with 1794 mtrr_chunk_size. 1795 1796 If unsure, say Y. 1797 1798config MTRR_SANITIZER_ENABLE_DEFAULT 1799 int "MTRR cleanup enable value (0-1)" 1800 range 0 1 1801 default "0" 1802 depends on MTRR_SANITIZER 1803 help 1804 Enable mtrr cleanup default value 1805 1806config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1807 int "MTRR cleanup spare reg num (0-7)" 1808 range 0 7 1809 default "1" 1810 depends on MTRR_SANITIZER 1811 help 1812 mtrr cleanup spare entries default, it can be changed via 1813 mtrr_spare_reg_nr=N on the kernel command line. 1814 1815config X86_PAT 1816 def_bool y 1817 prompt "x86 PAT support" if EXPERT 1818 depends on MTRR 1819 help 1820 Use PAT attributes to setup page level cache control. 1821 1822 PATs are the modern equivalents of MTRRs and are much more 1823 flexible than MTRRs. 1824 1825 Say N here if you see bootup problems (boot crash, boot hang, 1826 spontaneous reboots) or a non-working video driver. 1827 1828 If unsure, say Y. 1829 1830config ARCH_USES_PG_UNCACHED 1831 def_bool y 1832 depends on X86_PAT 1833 1834config ARCH_RANDOM 1835 def_bool y 1836 prompt "x86 architectural random number generator" if EXPERT 1837 help 1838 Enable the x86 architectural RDRAND instruction 1839 (Intel Bull Mountain technology) to generate random numbers. 1840 If supported, this is a high bandwidth, cryptographically 1841 secure hardware random number generator. 1842 1843config X86_SMAP 1844 def_bool y 1845 prompt "Supervisor Mode Access Prevention" if EXPERT 1846 help 1847 Supervisor Mode Access Prevention (SMAP) is a security 1848 feature in newer Intel processors. There is a small 1849 performance cost if this enabled and turned on; there is 1850 also a small increase in the kernel size if this is enabled. 1851 1852 If unsure, say Y. 1853 1854config X86_UMIP 1855 def_bool y 1856 prompt "User Mode Instruction Prevention" if EXPERT 1857 help 1858 User Mode Instruction Prevention (UMIP) is a security feature in 1859 some x86 processors. If enabled, a general protection fault is 1860 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1861 executed in user mode. These instructions unnecessarily expose 1862 information about the hardware state. 1863 1864 The vast majority of applications do not use these instructions. 1865 For the very few that do, software emulation is provided in 1866 specific cases in protected and virtual-8086 modes. Emulated 1867 results are dummy. 1868 1869config X86_INTEL_MEMORY_PROTECTION_KEYS 1870 prompt "Memory Protection Keys" 1871 def_bool y 1872 # Note: only available in 64-bit mode 1873 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1874 select ARCH_USES_HIGH_VMA_FLAGS 1875 select ARCH_HAS_PKEYS 1876 help 1877 Memory Protection Keys provides a mechanism for enforcing 1878 page-based protections, but without requiring modification of the 1879 page tables when an application changes protection domains. 1880 1881 For details, see Documentation/core-api/protection-keys.rst 1882 1883 If unsure, say y. 1884 1885choice 1886 prompt "TSX enable mode" 1887 depends on CPU_SUP_INTEL 1888 default X86_INTEL_TSX_MODE_OFF 1889 help 1890 Intel's TSX (Transactional Synchronization Extensions) feature 1891 allows to optimize locking protocols through lock elision which 1892 can lead to a noticeable performance boost. 1893 1894 On the other hand it has been shown that TSX can be exploited 1895 to form side channel attacks (e.g. TAA) and chances are there 1896 will be more of those attacks discovered in the future. 1897 1898 Therefore TSX is not enabled by default (aka tsx=off). An admin 1899 might override this decision by tsx=on the command line parameter. 1900 Even with TSX enabled, the kernel will attempt to enable the best 1901 possible TAA mitigation setting depending on the microcode available 1902 for the particular machine. 1903 1904 This option allows to set the default tsx mode between tsx=on, =off 1905 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1906 details. 1907 1908 Say off if not sure, auto if TSX is in use but it should be used on safe 1909 platforms or on if TSX is in use and the security aspect of tsx is not 1910 relevant. 1911 1912config X86_INTEL_TSX_MODE_OFF 1913 bool "off" 1914 help 1915 TSX is disabled if possible - equals to tsx=off command line parameter. 1916 1917config X86_INTEL_TSX_MODE_ON 1918 bool "on" 1919 help 1920 TSX is always enabled on TSX capable HW - equals the tsx=on command 1921 line parameter. 1922 1923config X86_INTEL_TSX_MODE_AUTO 1924 bool "auto" 1925 help 1926 TSX is enabled on TSX capable HW that is believed to be safe against 1927 side channel attacks- equals the tsx=auto command line parameter. 1928endchoice 1929 1930config EFI 1931 bool "EFI runtime service support" 1932 depends on ACPI 1933 select UCS2_STRING 1934 select EFI_RUNTIME_WRAPPERS 1935 help 1936 This enables the kernel to use EFI runtime services that are 1937 available (such as the EFI variable services). 1938 1939 This option is only useful on systems that have EFI firmware. 1940 In addition, you should use the latest ELILO loader available 1941 at <http://elilo.sourceforge.net> in order to take advantage 1942 of EFI runtime services. However, even with this option, the 1943 resultant kernel should continue to boot on existing non-EFI 1944 platforms. 1945 1946config EFI_STUB 1947 bool "EFI stub support" 1948 depends on EFI && !X86_USE_3DNOW 1949 depends on $(cc-option,-mabi=ms) || X86_32 1950 select RELOCATABLE 1951 help 1952 This kernel feature allows a bzImage to be loaded directly 1953 by EFI firmware without the use of a bootloader. 1954 1955 See Documentation/admin-guide/efi-stub.rst for more information. 1956 1957config EFI_MIXED 1958 bool "EFI mixed-mode support" 1959 depends on EFI_STUB && X86_64 1960 help 1961 Enabling this feature allows a 64-bit kernel to be booted 1962 on a 32-bit firmware, provided that your CPU supports 64-bit 1963 mode. 1964 1965 Note that it is not possible to boot a mixed-mode enabled 1966 kernel via the EFI boot stub - a bootloader that supports 1967 the EFI handover protocol must be used. 1968 1969 If unsure, say N. 1970 1971config SECCOMP 1972 def_bool y 1973 prompt "Enable seccomp to safely compute untrusted bytecode" 1974 help 1975 This kernel feature is useful for number crunching applications 1976 that may need to compute untrusted bytecode during their 1977 execution. By using pipes or other transports made available to 1978 the process as file descriptors supporting the read/write 1979 syscalls, it's possible to isolate those applications in 1980 their own address space using seccomp. Once seccomp is 1981 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1982 and the task is only allowed to execute a few safe syscalls 1983 defined by each seccomp mode. 1984 1985 If unsure, say Y. Only embedded should say N here. 1986 1987source "kernel/Kconfig.hz" 1988 1989config KEXEC 1990 bool "kexec system call" 1991 select KEXEC_CORE 1992 help 1993 kexec is a system call that implements the ability to shutdown your 1994 current kernel, and to start another kernel. It is like a reboot 1995 but it is independent of the system firmware. And like a reboot 1996 you can start any kernel with it, not just Linux. 1997 1998 The name comes from the similarity to the exec system call. 1999 2000 It is an ongoing process to be certain the hardware in a machine 2001 is properly shutdown, so do not be surprised if this code does not 2002 initially work for you. As of this writing the exact hardware 2003 interface is strongly in flux, so no good recommendation can be 2004 made. 2005 2006config KEXEC_FILE 2007 bool "kexec file based system call" 2008 select KEXEC_CORE 2009 select BUILD_BIN2C 2010 depends on X86_64 2011 depends on CRYPTO=y 2012 depends on CRYPTO_SHA256=y 2013 help 2014 This is new version of kexec system call. This system call is 2015 file based and takes file descriptors as system call argument 2016 for kernel and initramfs as opposed to list of segments as 2017 accepted by previous system call. 2018 2019config ARCH_HAS_KEXEC_PURGATORY 2020 def_bool KEXEC_FILE 2021 2022config KEXEC_SIG 2023 bool "Verify kernel signature during kexec_file_load() syscall" 2024 depends on KEXEC_FILE 2025 help 2026 2027 This option makes the kexec_file_load() syscall check for a valid 2028 signature of the kernel image. The image can still be loaded without 2029 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2030 there's a signature that we can check, then it must be valid. 2031 2032 In addition to this option, you need to enable signature 2033 verification for the corresponding kernel image type being 2034 loaded in order for this to work. 2035 2036config KEXEC_SIG_FORCE 2037 bool "Require a valid signature in kexec_file_load() syscall" 2038 depends on KEXEC_SIG 2039 help 2040 This option makes kernel signature verification mandatory for 2041 the kexec_file_load() syscall. 2042 2043config KEXEC_BZIMAGE_VERIFY_SIG 2044 bool "Enable bzImage signature verification support" 2045 depends on KEXEC_SIG 2046 depends on SIGNED_PE_FILE_VERIFICATION 2047 select SYSTEM_TRUSTED_KEYRING 2048 help 2049 Enable bzImage signature verification support. 2050 2051config CRASH_DUMP 2052 bool "kernel crash dumps" 2053 depends on X86_64 || (X86_32 && HIGHMEM) 2054 help 2055 Generate crash dump after being started by kexec. 2056 This should be normally only set in special crash dump kernels 2057 which are loaded in the main kernel with kexec-tools into 2058 a specially reserved region and then later executed after 2059 a crash by kdump/kexec. The crash dump kernel must be compiled 2060 to a memory address not used by the main kernel or BIOS using 2061 PHYSICAL_START, or it must be built as a relocatable image 2062 (CONFIG_RELOCATABLE=y). 2063 For more details see Documentation/admin-guide/kdump/kdump.rst 2064 2065config KEXEC_JUMP 2066 bool "kexec jump" 2067 depends on KEXEC && HIBERNATION 2068 help 2069 Jump between original kernel and kexeced kernel and invoke 2070 code in physical address mode via KEXEC 2071 2072config PHYSICAL_START 2073 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2074 default "0x1000000" 2075 help 2076 This gives the physical address where the kernel is loaded. 2077 2078 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2079 bzImage will decompress itself to above physical address and 2080 run from there. Otherwise, bzImage will run from the address where 2081 it has been loaded by the boot loader and will ignore above physical 2082 address. 2083 2084 In normal kdump cases one does not have to set/change this option 2085 as now bzImage can be compiled as a completely relocatable image 2086 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2087 address. This option is mainly useful for the folks who don't want 2088 to use a bzImage for capturing the crash dump and want to use a 2089 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2090 to be specifically compiled to run from a specific memory area 2091 (normally a reserved region) and this option comes handy. 2092 2093 So if you are using bzImage for capturing the crash dump, 2094 leave the value here unchanged to 0x1000000 and set 2095 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2096 for capturing the crash dump change this value to start of 2097 the reserved region. In other words, it can be set based on 2098 the "X" value as specified in the "crashkernel=YM@XM" 2099 command line boot parameter passed to the panic-ed 2100 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2101 for more details about crash dumps. 2102 2103 Usage of bzImage for capturing the crash dump is recommended as 2104 one does not have to build two kernels. Same kernel can be used 2105 as production kernel and capture kernel. Above option should have 2106 gone away after relocatable bzImage support is introduced. But it 2107 is present because there are users out there who continue to use 2108 vmlinux for dump capture. This option should go away down the 2109 line. 2110 2111 Don't change this unless you know what you are doing. 2112 2113config RELOCATABLE 2114 bool "Build a relocatable kernel" 2115 default y 2116 help 2117 This builds a kernel image that retains relocation information 2118 so it can be loaded someplace besides the default 1MB. 2119 The relocations tend to make the kernel binary about 10% larger, 2120 but are discarded at runtime. 2121 2122 One use is for the kexec on panic case where the recovery kernel 2123 must live at a different physical address than the primary 2124 kernel. 2125 2126 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2127 it has been loaded at and the compile time physical address 2128 (CONFIG_PHYSICAL_START) is used as the minimum location. 2129 2130config RANDOMIZE_BASE 2131 bool "Randomize the address of the kernel image (KASLR)" 2132 depends on RELOCATABLE 2133 default y 2134 help 2135 In support of Kernel Address Space Layout Randomization (KASLR), 2136 this randomizes the physical address at which the kernel image 2137 is decompressed and the virtual address where the kernel 2138 image is mapped, as a security feature that deters exploit 2139 attempts relying on knowledge of the location of kernel 2140 code internals. 2141 2142 On 64-bit, the kernel physical and virtual addresses are 2143 randomized separately. The physical address will be anywhere 2144 between 16MB and the top of physical memory (up to 64TB). The 2145 virtual address will be randomized from 16MB up to 1GB (9 bits 2146 of entropy). Note that this also reduces the memory space 2147 available to kernel modules from 1.5GB to 1GB. 2148 2149 On 32-bit, the kernel physical and virtual addresses are 2150 randomized together. They will be randomized from 16MB up to 2151 512MB (8 bits of entropy). 2152 2153 Entropy is generated using the RDRAND instruction if it is 2154 supported. If RDTSC is supported, its value is mixed into 2155 the entropy pool as well. If neither RDRAND nor RDTSC are 2156 supported, then entropy is read from the i8254 timer. The 2157 usable entropy is limited by the kernel being built using 2158 2GB addressing, and that PHYSICAL_ALIGN must be at a 2159 minimum of 2MB. As a result, only 10 bits of entropy are 2160 theoretically possible, but the implementations are further 2161 limited due to memory layouts. 2162 2163 If unsure, say Y. 2164 2165# Relocation on x86 needs some additional build support 2166config X86_NEED_RELOCS 2167 def_bool y 2168 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2169 2170config PHYSICAL_ALIGN 2171 hex "Alignment value to which kernel should be aligned" 2172 default "0x200000" 2173 range 0x2000 0x1000000 if X86_32 2174 range 0x200000 0x1000000 if X86_64 2175 help 2176 This value puts the alignment restrictions on physical address 2177 where kernel is loaded and run from. Kernel is compiled for an 2178 address which meets above alignment restriction. 2179 2180 If bootloader loads the kernel at a non-aligned address and 2181 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2182 address aligned to above value and run from there. 2183 2184 If bootloader loads the kernel at a non-aligned address and 2185 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2186 load address and decompress itself to the address it has been 2187 compiled for and run from there. The address for which kernel is 2188 compiled already meets above alignment restrictions. Hence the 2189 end result is that kernel runs from a physical address meeting 2190 above alignment restrictions. 2191 2192 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2193 this value must be a multiple of 0x200000. 2194 2195 Don't change this unless you know what you are doing. 2196 2197config DYNAMIC_MEMORY_LAYOUT 2198 bool 2199 help 2200 This option makes base addresses of vmalloc and vmemmap as well as 2201 __PAGE_OFFSET movable during boot. 2202 2203config RANDOMIZE_MEMORY 2204 bool "Randomize the kernel memory sections" 2205 depends on X86_64 2206 depends on RANDOMIZE_BASE 2207 select DYNAMIC_MEMORY_LAYOUT 2208 default RANDOMIZE_BASE 2209 help 2210 Randomizes the base virtual address of kernel memory sections 2211 (physical memory mapping, vmalloc & vmemmap). This security feature 2212 makes exploits relying on predictable memory locations less reliable. 2213 2214 The order of allocations remains unchanged. Entropy is generated in 2215 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2216 configuration have in average 30,000 different possible virtual 2217 addresses for each memory section. 2218 2219 If unsure, say Y. 2220 2221config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2222 hex "Physical memory mapping padding" if EXPERT 2223 depends on RANDOMIZE_MEMORY 2224 default "0xa" if MEMORY_HOTPLUG 2225 default "0x0" 2226 range 0x1 0x40 if MEMORY_HOTPLUG 2227 range 0x0 0x40 2228 help 2229 Define the padding in terabytes added to the existing physical 2230 memory size during kernel memory randomization. It is useful 2231 for memory hotplug support but reduces the entropy available for 2232 address randomization. 2233 2234 If unsure, leave at the default value. 2235 2236config HOTPLUG_CPU 2237 def_bool y 2238 depends on SMP 2239 2240config BOOTPARAM_HOTPLUG_CPU0 2241 bool "Set default setting of cpu0_hotpluggable" 2242 depends on HOTPLUG_CPU 2243 help 2244 Set whether default state of cpu0_hotpluggable is on or off. 2245 2246 Say Y here to enable CPU0 hotplug by default. If this switch 2247 is turned on, there is no need to give cpu0_hotplug kernel 2248 parameter and the CPU0 hotplug feature is enabled by default. 2249 2250 Please note: there are two known CPU0 dependencies if you want 2251 to enable the CPU0 hotplug feature either by this switch or by 2252 cpu0_hotplug kernel parameter. 2253 2254 First, resume from hibernate or suspend always starts from CPU0. 2255 So hibernate and suspend are prevented if CPU0 is offline. 2256 2257 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2258 offline if any interrupt can not migrate out of CPU0. There may 2259 be other CPU0 dependencies. 2260 2261 Please make sure the dependencies are under your control before 2262 you enable this feature. 2263 2264 Say N if you don't want to enable CPU0 hotplug feature by default. 2265 You still can enable the CPU0 hotplug feature at boot by kernel 2266 parameter cpu0_hotplug. 2267 2268config DEBUG_HOTPLUG_CPU0 2269 def_bool n 2270 prompt "Debug CPU0 hotplug" 2271 depends on HOTPLUG_CPU 2272 help 2273 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2274 soon as possible and boots up userspace with CPU0 offlined. User 2275 can online CPU0 back after boot time. 2276 2277 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2278 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2279 compilation or giving cpu0_hotplug kernel parameter at boot. 2280 2281 If unsure, say N. 2282 2283config COMPAT_VDSO 2284 def_bool n 2285 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2286 depends on COMPAT_32 2287 help 2288 Certain buggy versions of glibc will crash if they are 2289 presented with a 32-bit vDSO that is not mapped at the address 2290 indicated in its segment table. 2291 2292 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2293 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2294 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2295 the only released version with the bug, but OpenSUSE 9 2296 contains a buggy "glibc 2.3.2". 2297 2298 The symptom of the bug is that everything crashes on startup, saying: 2299 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2300 2301 Saying Y here changes the default value of the vdso32 boot 2302 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2303 This works around the glibc bug but hurts performance. 2304 2305 If unsure, say N: if you are compiling your own kernel, you 2306 are unlikely to be using a buggy version of glibc. 2307 2308choice 2309 prompt "vsyscall table for legacy applications" 2310 depends on X86_64 2311 default LEGACY_VSYSCALL_XONLY 2312 help 2313 Legacy user code that does not know how to find the vDSO expects 2314 to be able to issue three syscalls by calling fixed addresses in 2315 kernel space. Since this location is not randomized with ASLR, 2316 it can be used to assist security vulnerability exploitation. 2317 2318 This setting can be changed at boot time via the kernel command 2319 line parameter vsyscall=[emulate|xonly|none]. 2320 2321 On a system with recent enough glibc (2.14 or newer) and no 2322 static binaries, you can say None without a performance penalty 2323 to improve security. 2324 2325 If unsure, select "Emulate execution only". 2326 2327 config LEGACY_VSYSCALL_EMULATE 2328 bool "Full emulation" 2329 help 2330 The kernel traps and emulates calls into the fixed vsyscall 2331 address mapping. This makes the mapping non-executable, but 2332 it still contains readable known contents, which could be 2333 used in certain rare security vulnerability exploits. This 2334 configuration is recommended when using legacy userspace 2335 that still uses vsyscalls along with legacy binary 2336 instrumentation tools that require code to be readable. 2337 2338 An example of this type of legacy userspace is running 2339 Pin on an old binary that still uses vsyscalls. 2340 2341 config LEGACY_VSYSCALL_XONLY 2342 bool "Emulate execution only" 2343 help 2344 The kernel traps and emulates calls into the fixed vsyscall 2345 address mapping and does not allow reads. This 2346 configuration is recommended when userspace might use the 2347 legacy vsyscall area but support for legacy binary 2348 instrumentation of legacy code is not needed. It mitigates 2349 certain uses of the vsyscall area as an ASLR-bypassing 2350 buffer. 2351 2352 config LEGACY_VSYSCALL_NONE 2353 bool "None" 2354 help 2355 There will be no vsyscall mapping at all. This will 2356 eliminate any risk of ASLR bypass due to the vsyscall 2357 fixed address mapping. Attempts to use the vsyscalls 2358 will be reported to dmesg, so that either old or 2359 malicious userspace programs can be identified. 2360 2361endchoice 2362 2363config CMDLINE_BOOL 2364 bool "Built-in kernel command line" 2365 help 2366 Allow for specifying boot arguments to the kernel at 2367 build time. On some systems (e.g. embedded ones), it is 2368 necessary or convenient to provide some or all of the 2369 kernel boot arguments with the kernel itself (that is, 2370 to not rely on the boot loader to provide them.) 2371 2372 To compile command line arguments into the kernel, 2373 set this option to 'Y', then fill in the 2374 boot arguments in CONFIG_CMDLINE. 2375 2376 Systems with fully functional boot loaders (i.e. non-embedded) 2377 should leave this option set to 'N'. 2378 2379config CMDLINE 2380 string "Built-in kernel command string" 2381 depends on CMDLINE_BOOL 2382 default "" 2383 help 2384 Enter arguments here that should be compiled into the kernel 2385 image and used at boot time. If the boot loader provides a 2386 command line at boot time, it is appended to this string to 2387 form the full kernel command line, when the system boots. 2388 2389 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2390 change this behavior. 2391 2392 In most cases, the command line (whether built-in or provided 2393 by the boot loader) should specify the device for the root 2394 file system. 2395 2396config CMDLINE_OVERRIDE 2397 bool "Built-in command line overrides boot loader arguments" 2398 depends on CMDLINE_BOOL && CMDLINE != "" 2399 help 2400 Set this option to 'Y' to have the kernel ignore the boot loader 2401 command line, and use ONLY the built-in command line. 2402 2403 This is used to work around broken boot loaders. This should 2404 be set to 'N' under normal conditions. 2405 2406config MODIFY_LDT_SYSCALL 2407 bool "Enable the LDT (local descriptor table)" if EXPERT 2408 default y 2409 help 2410 Linux can allow user programs to install a per-process x86 2411 Local Descriptor Table (LDT) using the modify_ldt(2) system 2412 call. This is required to run 16-bit or segmented code such as 2413 DOSEMU or some Wine programs. It is also used by some very old 2414 threading libraries. 2415 2416 Enabling this feature adds a small amount of overhead to 2417 context switches and increases the low-level kernel attack 2418 surface. Disabling it removes the modify_ldt(2) system call. 2419 2420 Saying 'N' here may make sense for embedded or server kernels. 2421 2422source "kernel/livepatch/Kconfig" 2423 2424endmenu 2425 2426config ARCH_HAS_ADD_PAGES 2427 def_bool y 2428 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2429 2430config ARCH_ENABLE_MEMORY_HOTPLUG 2431 def_bool y 2432 depends on X86_64 || (X86_32 && HIGHMEM) 2433 2434config ARCH_ENABLE_MEMORY_HOTREMOVE 2435 def_bool y 2436 depends on MEMORY_HOTPLUG 2437 2438config USE_PERCPU_NUMA_NODE_ID 2439 def_bool y 2440 depends on NUMA 2441 2442config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2443 def_bool y 2444 depends on X86_64 || X86_PAE 2445 2446config ARCH_ENABLE_HUGEPAGE_MIGRATION 2447 def_bool y 2448 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2449 2450config ARCH_ENABLE_THP_MIGRATION 2451 def_bool y 2452 depends on X86_64 && TRANSPARENT_HUGEPAGE 2453 2454menu "Power management and ACPI options" 2455 2456config ARCH_HIBERNATION_HEADER 2457 def_bool y 2458 depends on HIBERNATION 2459 2460source "kernel/power/Kconfig" 2461 2462source "drivers/acpi/Kconfig" 2463 2464source "drivers/sfi/Kconfig" 2465 2466config X86_APM_BOOT 2467 def_bool y 2468 depends on APM 2469 2470menuconfig APM 2471 tristate "APM (Advanced Power Management) BIOS support" 2472 depends on X86_32 && PM_SLEEP 2473 help 2474 APM is a BIOS specification for saving power using several different 2475 techniques. This is mostly useful for battery powered laptops with 2476 APM compliant BIOSes. If you say Y here, the system time will be 2477 reset after a RESUME operation, the /proc/apm device will provide 2478 battery status information, and user-space programs will receive 2479 notification of APM "events" (e.g. battery status change). 2480 2481 If you select "Y" here, you can disable actual use of the APM 2482 BIOS by passing the "apm=off" option to the kernel at boot time. 2483 2484 Note that the APM support is almost completely disabled for 2485 machines with more than one CPU. 2486 2487 In order to use APM, you will need supporting software. For location 2488 and more information, read <file:Documentation/power/apm-acpi.rst> 2489 and the Battery Powered Linux mini-HOWTO, available from 2490 <http://www.tldp.org/docs.html#howto>. 2491 2492 This driver does not spin down disk drives (see the hdparm(8) 2493 manpage ("man 8 hdparm") for that), and it doesn't turn off 2494 VESA-compliant "green" monitors. 2495 2496 This driver does not support the TI 4000M TravelMate and the ACER 2497 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2498 desktop machines also don't have compliant BIOSes, and this driver 2499 may cause those machines to panic during the boot phase. 2500 2501 Generally, if you don't have a battery in your machine, there isn't 2502 much point in using this driver and you should say N. If you get 2503 random kernel OOPSes or reboots that don't seem to be related to 2504 anything, try disabling/enabling this option (or disabling/enabling 2505 APM in your BIOS). 2506 2507 Some other things you should try when experiencing seemingly random, 2508 "weird" problems: 2509 2510 1) make sure that you have enough swap space and that it is 2511 enabled. 2512 2) pass the "no-hlt" option to the kernel 2513 3) switch on floating point emulation in the kernel and pass 2514 the "no387" option to the kernel 2515 4) pass the "floppy=nodma" option to the kernel 2516 5) pass the "mem=4M" option to the kernel (thereby disabling 2517 all but the first 4 MB of RAM) 2518 6) make sure that the CPU is not over clocked. 2519 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2520 8) disable the cache from your BIOS settings 2521 9) install a fan for the video card or exchange video RAM 2522 10) install a better fan for the CPU 2523 11) exchange RAM chips 2524 12) exchange the motherboard. 2525 2526 To compile this driver as a module, choose M here: the 2527 module will be called apm. 2528 2529if APM 2530 2531config APM_IGNORE_USER_SUSPEND 2532 bool "Ignore USER SUSPEND" 2533 help 2534 This option will ignore USER SUSPEND requests. On machines with a 2535 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2536 series notebooks, it is necessary to say Y because of a BIOS bug. 2537 2538config APM_DO_ENABLE 2539 bool "Enable PM at boot time" 2540 help 2541 Enable APM features at boot time. From page 36 of the APM BIOS 2542 specification: "When disabled, the APM BIOS does not automatically 2543 power manage devices, enter the Standby State, enter the Suspend 2544 State, or take power saving steps in response to CPU Idle calls." 2545 This driver will make CPU Idle calls when Linux is idle (unless this 2546 feature is turned off -- see "Do CPU IDLE calls", below). This 2547 should always save battery power, but more complicated APM features 2548 will be dependent on your BIOS implementation. You may need to turn 2549 this option off if your computer hangs at boot time when using APM 2550 support, or if it beeps continuously instead of suspending. Turn 2551 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2552 T400CDT. This is off by default since most machines do fine without 2553 this feature. 2554 2555config APM_CPU_IDLE 2556 depends on CPU_IDLE 2557 bool "Make CPU Idle calls when idle" 2558 help 2559 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2560 On some machines, this can activate improved power savings, such as 2561 a slowed CPU clock rate, when the machine is idle. These idle calls 2562 are made after the idle loop has run for some length of time (e.g., 2563 333 mS). On some machines, this will cause a hang at boot time or 2564 whenever the CPU becomes idle. (On machines with more than one CPU, 2565 this option does nothing.) 2566 2567config APM_DISPLAY_BLANK 2568 bool "Enable console blanking using APM" 2569 help 2570 Enable console blanking using the APM. Some laptops can use this to 2571 turn off the LCD backlight when the screen blanker of the Linux 2572 virtual console blanks the screen. Note that this is only used by 2573 the virtual console screen blanker, and won't turn off the backlight 2574 when using the X Window system. This also doesn't have anything to 2575 do with your VESA-compliant power-saving monitor. Further, this 2576 option doesn't work for all laptops -- it might not turn off your 2577 backlight at all, or it might print a lot of errors to the console, 2578 especially if you are using gpm. 2579 2580config APM_ALLOW_INTS 2581 bool "Allow interrupts during APM BIOS calls" 2582 help 2583 Normally we disable external interrupts while we are making calls to 2584 the APM BIOS as a measure to lessen the effects of a badly behaving 2585 BIOS implementation. The BIOS should reenable interrupts if it 2586 needs to. Unfortunately, some BIOSes do not -- especially those in 2587 many of the newer IBM Thinkpads. If you experience hangs when you 2588 suspend, try setting this to Y. Otherwise, say N. 2589 2590endif # APM 2591 2592source "drivers/cpufreq/Kconfig" 2593 2594source "drivers/cpuidle/Kconfig" 2595 2596source "drivers/idle/Kconfig" 2597 2598endmenu 2599 2600 2601menu "Bus options (PCI etc.)" 2602 2603choice 2604 prompt "PCI access mode" 2605 depends on X86_32 && PCI 2606 default PCI_GOANY 2607 help 2608 On PCI systems, the BIOS can be used to detect the PCI devices and 2609 determine their configuration. However, some old PCI motherboards 2610 have BIOS bugs and may crash if this is done. Also, some embedded 2611 PCI-based systems don't have any BIOS at all. Linux can also try to 2612 detect the PCI hardware directly without using the BIOS. 2613 2614 With this option, you can specify how Linux should detect the 2615 PCI devices. If you choose "BIOS", the BIOS will be used, 2616 if you choose "Direct", the BIOS won't be used, and if you 2617 choose "MMConfig", then PCI Express MMCONFIG will be used. 2618 If you choose "Any", the kernel will try MMCONFIG, then the 2619 direct access method and falls back to the BIOS if that doesn't 2620 work. If unsure, go with the default, which is "Any". 2621 2622config PCI_GOBIOS 2623 bool "BIOS" 2624 2625config PCI_GOMMCONFIG 2626 bool "MMConfig" 2627 2628config PCI_GODIRECT 2629 bool "Direct" 2630 2631config PCI_GOOLPC 2632 bool "OLPC XO-1" 2633 depends on OLPC 2634 2635config PCI_GOANY 2636 bool "Any" 2637 2638endchoice 2639 2640config PCI_BIOS 2641 def_bool y 2642 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2643 2644# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2645config PCI_DIRECT 2646 def_bool y 2647 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2648 2649config PCI_MMCONFIG 2650 bool "Support mmconfig PCI config space access" if X86_64 2651 default y 2652 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2653 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2654 2655config PCI_OLPC 2656 def_bool y 2657 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2658 2659config PCI_XEN 2660 def_bool y 2661 depends on PCI && XEN 2662 select SWIOTLB_XEN 2663 2664config MMCONF_FAM10H 2665 def_bool y 2666 depends on X86_64 && PCI_MMCONFIG && ACPI 2667 2668config PCI_CNB20LE_QUIRK 2669 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2670 depends on PCI 2671 help 2672 Read the PCI windows out of the CNB20LE host bridge. This allows 2673 PCI hotplug to work on systems with the CNB20LE chipset which do 2674 not have ACPI. 2675 2676 There's no public spec for this chipset, and this functionality 2677 is known to be incomplete. 2678 2679 You should say N unless you know you need this. 2680 2681config ISA_BUS 2682 bool "ISA bus support on modern systems" if EXPERT 2683 help 2684 Expose ISA bus device drivers and options available for selection and 2685 configuration. Enable this option if your target machine has an ISA 2686 bus. ISA is an older system, displaced by PCI and newer bus 2687 architectures -- if your target machine is modern, it probably does 2688 not have an ISA bus. 2689 2690 If unsure, say N. 2691 2692# x86_64 have no ISA slots, but can have ISA-style DMA. 2693config ISA_DMA_API 2694 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2695 default y 2696 help 2697 Enables ISA-style DMA support for devices requiring such controllers. 2698 If unsure, say Y. 2699 2700if X86_32 2701 2702config ISA 2703 bool "ISA support" 2704 help 2705 Find out whether you have ISA slots on your motherboard. ISA is the 2706 name of a bus system, i.e. the way the CPU talks to the other stuff 2707 inside your box. Other bus systems are PCI, EISA, MicroChannel 2708 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2709 newer boards don't support it. If you have ISA, say Y, otherwise N. 2710 2711config SCx200 2712 tristate "NatSemi SCx200 support" 2713 help 2714 This provides basic support for National Semiconductor's 2715 (now AMD's) Geode processors. The driver probes for the 2716 PCI-IDs of several on-chip devices, so its a good dependency 2717 for other scx200_* drivers. 2718 2719 If compiled as a module, the driver is named scx200. 2720 2721config SCx200HR_TIMER 2722 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2723 depends on SCx200 2724 default y 2725 help 2726 This driver provides a clocksource built upon the on-chip 2727 27MHz high-resolution timer. Its also a workaround for 2728 NSC Geode SC-1100's buggy TSC, which loses time when the 2729 processor goes idle (as is done by the scheduler). The 2730 other workaround is idle=poll boot option. 2731 2732config OLPC 2733 bool "One Laptop Per Child support" 2734 depends on !X86_PAE 2735 select GPIOLIB 2736 select OF 2737 select OF_PROMTREE 2738 select IRQ_DOMAIN 2739 select OLPC_EC 2740 help 2741 Add support for detecting the unique features of the OLPC 2742 XO hardware. 2743 2744config OLPC_XO1_PM 2745 bool "OLPC XO-1 Power Management" 2746 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2747 help 2748 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2749 2750config OLPC_XO1_RTC 2751 bool "OLPC XO-1 Real Time Clock" 2752 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2753 help 2754 Add support for the XO-1 real time clock, which can be used as a 2755 programmable wakeup source. 2756 2757config OLPC_XO1_SCI 2758 bool "OLPC XO-1 SCI extras" 2759 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2760 depends on INPUT=y 2761 select POWER_SUPPLY 2762 help 2763 Add support for SCI-based features of the OLPC XO-1 laptop: 2764 - EC-driven system wakeups 2765 - Power button 2766 - Ebook switch 2767 - Lid switch 2768 - AC adapter status updates 2769 - Battery status updates 2770 2771config OLPC_XO15_SCI 2772 bool "OLPC XO-1.5 SCI extras" 2773 depends on OLPC && ACPI 2774 select POWER_SUPPLY 2775 help 2776 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2777 - EC-driven system wakeups 2778 - AC adapter status updates 2779 - Battery status updates 2780 2781config ALIX 2782 bool "PCEngines ALIX System Support (LED setup)" 2783 select GPIOLIB 2784 help 2785 This option enables system support for the PCEngines ALIX. 2786 At present this just sets up LEDs for GPIO control on 2787 ALIX2/3/6 boards. However, other system specific setup should 2788 get added here. 2789 2790 Note: You must still enable the drivers for GPIO and LED support 2791 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2792 2793 Note: You have to set alix.force=1 for boards with Award BIOS. 2794 2795config NET5501 2796 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2797 select GPIOLIB 2798 help 2799 This option enables system support for the Soekris Engineering net5501. 2800 2801config GEOS 2802 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2803 select GPIOLIB 2804 depends on DMI 2805 help 2806 This option enables system support for the Traverse Technologies GEOS. 2807 2808config TS5500 2809 bool "Technologic Systems TS-5500 platform support" 2810 depends on MELAN 2811 select CHECK_SIGNATURE 2812 select NEW_LEDS 2813 select LEDS_CLASS 2814 help 2815 This option enables system support for the Technologic Systems TS-5500. 2816 2817endif # X86_32 2818 2819config AMD_NB 2820 def_bool y 2821 depends on CPU_SUP_AMD && PCI 2822 2823config X86_SYSFB 2824 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2825 help 2826 Firmwares often provide initial graphics framebuffers so the BIOS, 2827 bootloader or kernel can show basic video-output during boot for 2828 user-guidance and debugging. Historically, x86 used the VESA BIOS 2829 Extensions and EFI-framebuffers for this, which are mostly limited 2830 to x86. 2831 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2832 framebuffers so the new generic system-framebuffer drivers can be 2833 used on x86. If the framebuffer is not compatible with the generic 2834 modes, it is advertised as fallback platform framebuffer so legacy 2835 drivers like efifb, vesafb and uvesafb can pick it up. 2836 If this option is not selected, all system framebuffers are always 2837 marked as fallback platform framebuffers as usual. 2838 2839 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2840 not be able to pick up generic system framebuffers if this option 2841 is selected. You are highly encouraged to enable simplefb as 2842 replacement if you select this option. simplefb can correctly deal 2843 with generic system framebuffers. But you should still keep vesafb 2844 and others enabled as fallback if a system framebuffer is 2845 incompatible with simplefb. 2846 2847 If unsure, say Y. 2848 2849endmenu 2850 2851 2852menu "Binary Emulations" 2853 2854config IA32_EMULATION 2855 bool "IA32 Emulation" 2856 depends on X86_64 2857 select ARCH_WANT_OLD_COMPAT_IPC 2858 select BINFMT_ELF 2859 select COMPAT_BINFMT_ELF 2860 select COMPAT_OLD_SIGACTION 2861 help 2862 Include code to run legacy 32-bit programs under a 2863 64-bit kernel. You should likely turn this on, unless you're 2864 100% sure that you don't have any 32-bit programs left. 2865 2866config IA32_AOUT 2867 tristate "IA32 a.out support" 2868 depends on IA32_EMULATION 2869 depends on BROKEN 2870 help 2871 Support old a.out binaries in the 32bit emulation. 2872 2873config X86_X32 2874 bool "x32 ABI for 64-bit mode" 2875 depends on X86_64 2876 help 2877 Include code to run binaries for the x32 native 32-bit ABI 2878 for 64-bit processors. An x32 process gets access to the 2879 full 64-bit register file and wide data path while leaving 2880 pointers at 32 bits for smaller memory footprint. 2881 2882 You will need a recent binutils (2.22 or later) with 2883 elf32_x86_64 support enabled to compile a kernel with this 2884 option set. 2885 2886config COMPAT_32 2887 def_bool y 2888 depends on IA32_EMULATION || X86_32 2889 select HAVE_UID16 2890 select OLD_SIGSUSPEND3 2891 2892config COMPAT 2893 def_bool y 2894 depends on IA32_EMULATION || X86_X32 2895 2896if COMPAT 2897config COMPAT_FOR_U64_ALIGNMENT 2898 def_bool y 2899 2900config SYSVIPC_COMPAT 2901 def_bool y 2902 depends on SYSVIPC 2903endif 2904 2905endmenu 2906 2907 2908config HAVE_ATOMIC_IOMAP 2909 def_bool y 2910 depends on X86_32 2911 2912source "drivers/firmware/Kconfig" 2913 2914source "arch/x86/kvm/Kconfig" 2915 2916source "arch/x86/Kconfig.assembler" 2917