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_AOUT 18 select HAVE_GENERIC_DMA_COHERENT 19 select MODULES_USE_ELF_REL 20 select OLD_SIGACTION 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 if (MEMORY_ISOLATION && COMPACTION) || CMA 27 select ARCH_SUPPORTS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select X86_DEV_DMA_OPS 32 33# 34# Arch settings 35# 36# ( Note that options that are marked 'if X86_64' could in principle be 37# ported to 32-bit as well. ) 38# 39config X86 40 def_bool y 41 # 42 # Note: keep this list sorted alphabetically 43 # 44 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 45 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 46 select ANON_INODES 47 select ARCH_CLOCKSOURCE_DATA 48 select ARCH_DISCARD_MEMBLOCK 49 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 50 select ARCH_HAS_DEBUG_VIRTUAL 51 select ARCH_HAS_DEVMEM_IS_ALLOWED 52 select ARCH_HAS_ELF_RANDOMIZE 53 select ARCH_HAS_FAST_MULTIPLIER 54 select ARCH_HAS_FORTIFY_SOURCE 55 select ARCH_HAS_GCOV_PROFILE_ALL 56 select ARCH_HAS_KCOV if X86_64 57 select ARCH_HAS_PHYS_TO_DMA 58 select ARCH_HAS_MEMBARRIER_SYNC_CORE 59 select ARCH_HAS_PMEM_API if X86_64 60 select ARCH_HAS_REFCOUNT 61 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 62 select ARCH_HAS_SET_MEMORY 63 select ARCH_HAS_SG_CHAIN 64 select ARCH_HAS_STRICT_KERNEL_RWX 65 select ARCH_HAS_STRICT_MODULE_RWX 66 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 67 select ARCH_HAS_UBSAN_SANITIZE_ALL 68 select ARCH_HAS_ZONE_DEVICE if X86_64 69 select ARCH_HAVE_NMI_SAFE_CMPXCHG 70 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 71 select ARCH_MIGHT_HAVE_PC_PARPORT 72 select ARCH_MIGHT_HAVE_PC_SERIO 73 select ARCH_SUPPORTS_ATOMIC_RMW 74 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 75 select ARCH_USE_BUILTIN_BSWAP 76 select ARCH_USE_QUEUED_RWLOCKS 77 select ARCH_USE_QUEUED_SPINLOCKS 78 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 79 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 80 select ARCH_WANTS_THP_SWAP if X86_64 81 select BUILDTIME_EXTABLE_SORT 82 select CLKEVT_I8253 83 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 84 select CLOCKSOURCE_WATCHDOG 85 select DCACHE_WORD_ACCESS 86 select EDAC_ATOMIC_SCRUB 87 select EDAC_SUPPORT 88 select GENERIC_CLOCKEVENTS 89 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 90 select GENERIC_CLOCKEVENTS_MIN_ADJUST 91 select GENERIC_CMOS_UPDATE 92 select GENERIC_CPU_AUTOPROBE 93 select GENERIC_CPU_VULNERABILITIES 94 select GENERIC_EARLY_IOREMAP 95 select GENERIC_FIND_FIRST_BIT 96 select GENERIC_IOMAP 97 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 98 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 99 select GENERIC_IRQ_MIGRATION if SMP 100 select GENERIC_IRQ_PROBE 101 select GENERIC_IRQ_RESERVATION_MODE 102 select GENERIC_IRQ_SHOW 103 select GENERIC_PENDING_IRQ if SMP 104 select GENERIC_SMP_IDLE_THREAD 105 select GENERIC_STRNCPY_FROM_USER 106 select GENERIC_STRNLEN_USER 107 select GENERIC_TIME_VSYSCALL 108 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 109 select HAVE_ACPI_APEI if ACPI 110 select HAVE_ACPI_APEI_NMI if ACPI 111 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 112 select HAVE_ARCH_AUDITSYSCALL 113 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 114 select HAVE_ARCH_JUMP_LABEL 115 select HAVE_ARCH_KASAN if X86_64 116 select HAVE_ARCH_KGDB 117 select HAVE_ARCH_MMAP_RND_BITS if MMU 118 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 119 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 120 select HAVE_ARCH_SECCOMP_FILTER 121 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 122 select HAVE_ARCH_TRACEHOOK 123 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 124 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 125 select HAVE_ARCH_VMAP_STACK if X86_64 126 select HAVE_ARCH_WITHIN_STACK_FRAMES 127 select HAVE_CC_STACKPROTECTOR 128 select HAVE_CMPXCHG_DOUBLE 129 select HAVE_CMPXCHG_LOCAL 130 select HAVE_CONTEXT_TRACKING if X86_64 131 select HAVE_COPY_THREAD_TLS 132 select HAVE_C_RECORDMCOUNT 133 select HAVE_DEBUG_KMEMLEAK 134 select HAVE_DEBUG_STACKOVERFLOW 135 select HAVE_DMA_API_DEBUG 136 select HAVE_DMA_CONTIGUOUS 137 select HAVE_DYNAMIC_FTRACE 138 select HAVE_DYNAMIC_FTRACE_WITH_REGS 139 select HAVE_EBPF_JIT if X86_64 140 select HAVE_EFFICIENT_UNALIGNED_ACCESS 141 select HAVE_EXIT_THREAD 142 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 143 select HAVE_FTRACE_MCOUNT_RECORD 144 select HAVE_FUNCTION_GRAPH_TRACER 145 select HAVE_FUNCTION_TRACER 146 select HAVE_GCC_PLUGINS 147 select HAVE_HW_BREAKPOINT 148 select HAVE_IDE 149 select HAVE_IOREMAP_PROT 150 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 151 select HAVE_IRQ_TIME_ACCOUNTING 152 select HAVE_KERNEL_BZIP2 153 select HAVE_KERNEL_GZIP 154 select HAVE_KERNEL_LZ4 155 select HAVE_KERNEL_LZMA 156 select HAVE_KERNEL_LZO 157 select HAVE_KERNEL_XZ 158 select HAVE_KPROBES 159 select HAVE_KPROBES_ON_FTRACE 160 select HAVE_FUNCTION_ERROR_INJECTION 161 select HAVE_KRETPROBES 162 select HAVE_KVM 163 select HAVE_LIVEPATCH if X86_64 164 select HAVE_MEMBLOCK 165 select HAVE_MEMBLOCK_NODE_MAP 166 select HAVE_MIXED_BREAKPOINTS_REGS 167 select HAVE_MOD_ARCH_SPECIFIC 168 select HAVE_NMI 169 select HAVE_OPROFILE 170 select HAVE_OPTPROBES 171 select HAVE_PCSPKR_PLATFORM 172 select HAVE_PERF_EVENTS 173 select HAVE_PERF_EVENTS_NMI 174 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 175 select HAVE_PERF_REGS 176 select HAVE_PERF_USER_STACK_DUMP 177 select HAVE_RCU_TABLE_FREE 178 select HAVE_REGS_AND_STACK_ACCESS_API 179 select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION 180 select HAVE_STACK_VALIDATION if X86_64 181 select HAVE_SYSCALL_TRACEPOINTS 182 select HAVE_UNSTABLE_SCHED_CLOCK 183 select HAVE_USER_RETURN_NOTIFIER 184 select IRQ_FORCED_THREADING 185 select PCI_LOCKLESS_CONFIG 186 select PERF_EVENTS 187 select RTC_LIB 188 select RTC_MC146818_LIB 189 select SPARSE_IRQ 190 select SRCU 191 select SYSCTL_EXCEPTION_TRACE 192 select THREAD_INFO_IN_TASK 193 select USER_STACKTRACE_SUPPORT 194 select VIRT_TO_BUS 195 select X86_FEATURE_NAMES if PROC_FS 196 197config INSTRUCTION_DECODER 198 def_bool y 199 depends on KPROBES || PERF_EVENTS || UPROBES 200 201config OUTPUT_FORMAT 202 string 203 default "elf32-i386" if X86_32 204 default "elf64-x86-64" if X86_64 205 206config ARCH_DEFCONFIG 207 string 208 default "arch/x86/configs/i386_defconfig" if X86_32 209 default "arch/x86/configs/x86_64_defconfig" if X86_64 210 211config LOCKDEP_SUPPORT 212 def_bool y 213 214config STACKTRACE_SUPPORT 215 def_bool y 216 217config MMU 218 def_bool y 219 220config ARCH_MMAP_RND_BITS_MIN 221 default 28 if 64BIT 222 default 8 223 224config ARCH_MMAP_RND_BITS_MAX 225 default 32 if 64BIT 226 default 16 227 228config ARCH_MMAP_RND_COMPAT_BITS_MIN 229 default 8 230 231config ARCH_MMAP_RND_COMPAT_BITS_MAX 232 default 16 233 234config SBUS 235 bool 236 237config NEED_DMA_MAP_STATE 238 def_bool y 239 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB 240 241config NEED_SG_DMA_LENGTH 242 def_bool y 243 244config GENERIC_ISA_DMA 245 def_bool y 246 depends on ISA_DMA_API 247 248config GENERIC_BUG 249 def_bool y 250 depends on BUG 251 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 252 253config GENERIC_BUG_RELATIVE_POINTERS 254 bool 255 256config GENERIC_HWEIGHT 257 def_bool y 258 259config ARCH_MAY_HAVE_PC_FDC 260 def_bool y 261 depends on ISA_DMA_API 262 263config RWSEM_XCHGADD_ALGORITHM 264 def_bool y 265 266config GENERIC_CALIBRATE_DELAY 267 def_bool y 268 269config ARCH_HAS_CPU_RELAX 270 def_bool y 271 272config ARCH_HAS_CACHE_LINE_SIZE 273 def_bool y 274 275config HAVE_SETUP_PER_CPU_AREA 276 def_bool y 277 278config NEED_PER_CPU_EMBED_FIRST_CHUNK 279 def_bool y 280 281config NEED_PER_CPU_PAGE_FIRST_CHUNK 282 def_bool y 283 284config ARCH_HIBERNATION_POSSIBLE 285 def_bool y 286 287config ARCH_SUSPEND_POSSIBLE 288 def_bool y 289 290config ARCH_WANT_HUGE_PMD_SHARE 291 def_bool y 292 293config ARCH_WANT_GENERAL_HUGETLB 294 def_bool y 295 296config ZONE_DMA32 297 def_bool y if X86_64 298 299config AUDIT_ARCH 300 def_bool y if X86_64 301 302config ARCH_SUPPORTS_OPTIMIZED_INLINING 303 def_bool y 304 305config ARCH_SUPPORTS_DEBUG_PAGEALLOC 306 def_bool y 307 308config KASAN_SHADOW_OFFSET 309 hex 310 depends on KASAN 311 default 0xdffffc0000000000 312 313config HAVE_INTEL_TXT 314 def_bool y 315 depends on INTEL_IOMMU && ACPI 316 317config X86_32_SMP 318 def_bool y 319 depends on X86_32 && SMP 320 321config X86_64_SMP 322 def_bool y 323 depends on X86_64 && SMP 324 325config X86_32_LAZY_GS 326 def_bool y 327 depends on X86_32 && CC_STACKPROTECTOR_NONE 328 329config ARCH_SUPPORTS_UPROBES 330 def_bool y 331 332config FIX_EARLYCON_MEM 333 def_bool y 334 335config PGTABLE_LEVELS 336 int 337 default 5 if X86_5LEVEL 338 default 4 if X86_64 339 default 3 if X86_PAE 340 default 2 341 342source "init/Kconfig" 343source "kernel/Kconfig.freezer" 344 345menu "Processor type and features" 346 347config ZONE_DMA 348 bool "DMA memory allocation support" if EXPERT 349 default y 350 help 351 DMA memory allocation support allows devices with less than 32-bit 352 addressing to allocate within the first 16MB of address space. 353 Disable if no such devices will be used. 354 355 If unsure, say Y. 356 357config SMP 358 bool "Symmetric multi-processing support" 359 ---help--- 360 This enables support for systems with more than one CPU. If you have 361 a system with only one CPU, say N. If you have a system with more 362 than one CPU, say Y. 363 364 If you say N here, the kernel will run on uni- and multiprocessor 365 machines, but will use only one CPU of a multiprocessor machine. If 366 you say Y here, the kernel will run on many, but not all, 367 uniprocessor machines. On a uniprocessor machine, the kernel 368 will run faster if you say N here. 369 370 Note that if you say Y here and choose architecture "586" or 371 "Pentium" under "Processor family", the kernel will not work on 486 372 architectures. Similarly, multiprocessor kernels for the "PPro" 373 architecture may not work on all Pentium based boards. 374 375 People using multiprocessor machines who say Y here should also say 376 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 377 Management" code will be disabled if you say Y here. 378 379 See also <file:Documentation/x86/i386/IO-APIC.txt>, 380 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at 381 <http://www.tldp.org/docs.html#howto>. 382 383 If you don't know what to do here, say N. 384 385config X86_FEATURE_NAMES 386 bool "Processor feature human-readable names" if EMBEDDED 387 default y 388 ---help--- 389 This option compiles in a table of x86 feature bits and corresponding 390 names. This is required to support /proc/cpuinfo and a few kernel 391 messages. You can disable this to save space, at the expense of 392 making those few kernel messages show numeric feature bits instead. 393 394 If in doubt, say Y. 395 396config X86_FAST_FEATURE_TESTS 397 bool "Fast CPU feature tests" if EMBEDDED 398 default y 399 ---help--- 400 Some fast-paths in the kernel depend on the capabilities of the CPU. 401 Say Y here for the kernel to patch in the appropriate code at runtime 402 based on the capabilities of the CPU. The infrastructure for patching 403 code at runtime takes up some additional space; space-constrained 404 embedded systems may wish to say N here to produce smaller, slightly 405 slower code. 406 407config X86_X2APIC 408 bool "Support x2apic" 409 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 410 ---help--- 411 This enables x2apic support on CPUs that have this feature. 412 413 This allows 32-bit apic IDs (so it can support very large systems), 414 and accesses the local apic via MSRs not via mmio. 415 416 If you don't know what to do here, say N. 417 418config X86_MPPARSE 419 bool "Enable MPS table" if ACPI || SFI 420 default y 421 depends on X86_LOCAL_APIC 422 ---help--- 423 For old smp systems that do not have proper acpi support. Newer systems 424 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 425 426config X86_BIGSMP 427 bool "Support for big SMP systems with more than 8 CPUs" 428 depends on X86_32 && SMP 429 ---help--- 430 This option is needed for the systems that have more than 8 CPUs 431 432config GOLDFISH 433 def_bool y 434 depends on X86_GOLDFISH 435 436config RETPOLINE 437 bool "Avoid speculative indirect branches in kernel" 438 default y 439 help 440 Compile kernel with the retpoline compiler options to guard against 441 kernel-to-user data leaks by avoiding speculative indirect 442 branches. Requires a compiler with -mindirect-branch=thunk-extern 443 support for full protection. The kernel may run slower. 444 445 Without compiler support, at least indirect branches in assembler 446 code are eliminated. Since this includes the syscall entry path, 447 it is not entirely pointless. 448 449config INTEL_RDT 450 bool "Intel Resource Director Technology support" 451 default n 452 depends on X86 && CPU_SUP_INTEL 453 select KERNFS 454 help 455 Select to enable resource allocation and monitoring which are 456 sub-features of Intel Resource Director Technology(RDT). More 457 information about RDT can be found in the Intel x86 458 Architecture Software Developer Manual. 459 460 Say N if unsure. 461 462if X86_32 463config X86_EXTENDED_PLATFORM 464 bool "Support for extended (non-PC) x86 platforms" 465 default y 466 ---help--- 467 If you disable this option then the kernel will only support 468 standard PC platforms. (which covers the vast majority of 469 systems out there.) 470 471 If you enable this option then you'll be able to select support 472 for the following (non-PC) 32 bit x86 platforms: 473 Goldfish (Android emulator) 474 AMD Elan 475 RDC R-321x SoC 476 SGI 320/540 (Visual Workstation) 477 STA2X11-based (e.g. Northville) 478 Moorestown MID devices 479 480 If you have one of these systems, or if you want to build a 481 generic distribution kernel, say Y here - otherwise say N. 482endif 483 484if X86_64 485config X86_EXTENDED_PLATFORM 486 bool "Support for extended (non-PC) x86 platforms" 487 default y 488 ---help--- 489 If you disable this option then the kernel will only support 490 standard PC platforms. (which covers the vast majority of 491 systems out there.) 492 493 If you enable this option then you'll be able to select support 494 for the following (non-PC) 64 bit x86 platforms: 495 Numascale NumaChip 496 ScaleMP vSMP 497 SGI Ultraviolet 498 499 If you have one of these systems, or if you want to build a 500 generic distribution kernel, say Y here - otherwise say N. 501endif 502# This is an alphabetically sorted list of 64 bit extended platforms 503# Please maintain the alphabetic order if and when there are additions 504config X86_NUMACHIP 505 bool "Numascale NumaChip" 506 depends on X86_64 507 depends on X86_EXTENDED_PLATFORM 508 depends on NUMA 509 depends on SMP 510 depends on X86_X2APIC 511 depends on PCI_MMCONFIG 512 ---help--- 513 Adds support for Numascale NumaChip large-SMP systems. Needed to 514 enable more than ~168 cores. 515 If you don't have one of these, you should say N here. 516 517config X86_VSMP 518 bool "ScaleMP vSMP" 519 select HYPERVISOR_GUEST 520 select PARAVIRT 521 depends on X86_64 && PCI 522 depends on X86_EXTENDED_PLATFORM 523 depends on SMP 524 ---help--- 525 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 526 supposed to run on these EM64T-based machines. Only choose this option 527 if you have one of these machines. 528 529config X86_UV 530 bool "SGI Ultraviolet" 531 depends on X86_64 532 depends on X86_EXTENDED_PLATFORM 533 depends on NUMA 534 depends on EFI 535 depends on X86_X2APIC 536 depends on PCI 537 ---help--- 538 This option is needed in order to support SGI Ultraviolet systems. 539 If you don't have one of these, you should say N here. 540 541# Following is an alphabetically sorted list of 32 bit extended platforms 542# Please maintain the alphabetic order if and when there are additions 543 544config X86_GOLDFISH 545 bool "Goldfish (Virtual Platform)" 546 depends on X86_EXTENDED_PLATFORM 547 ---help--- 548 Enable support for the Goldfish virtual platform used primarily 549 for Android development. Unless you are building for the Android 550 Goldfish emulator say N here. 551 552config X86_INTEL_CE 553 bool "CE4100 TV platform" 554 depends on PCI 555 depends on PCI_GODIRECT 556 depends on X86_IO_APIC 557 depends on X86_32 558 depends on X86_EXTENDED_PLATFORM 559 select X86_REBOOTFIXUPS 560 select OF 561 select OF_EARLY_FLATTREE 562 ---help--- 563 Select for the Intel CE media processor (CE4100) SOC. 564 This option compiles in support for the CE4100 SOC for settop 565 boxes and media devices. 566 567config X86_INTEL_MID 568 bool "Intel MID platform support" 569 depends on X86_EXTENDED_PLATFORM 570 depends on X86_PLATFORM_DEVICES 571 depends on PCI 572 depends on X86_64 || (PCI_GOANY && X86_32) 573 depends on X86_IO_APIC 574 select SFI 575 select I2C 576 select DW_APB_TIMER 577 select APB_TIMER 578 select INTEL_SCU_IPC 579 select MFD_INTEL_MSIC 580 ---help--- 581 Select to build a kernel capable of supporting Intel MID (Mobile 582 Internet Device) platform systems which do not have the PCI legacy 583 interfaces. If you are building for a PC class system say N here. 584 585 Intel MID platforms are based on an Intel processor and chipset which 586 consume less power than most of the x86 derivatives. 587 588config X86_INTEL_QUARK 589 bool "Intel Quark platform support" 590 depends on X86_32 591 depends on X86_EXTENDED_PLATFORM 592 depends on X86_PLATFORM_DEVICES 593 depends on X86_TSC 594 depends on PCI 595 depends on PCI_GOANY 596 depends on X86_IO_APIC 597 select IOSF_MBI 598 select INTEL_IMR 599 select COMMON_CLK 600 ---help--- 601 Select to include support for Quark X1000 SoC. 602 Say Y here if you have a Quark based system such as the Arduino 603 compatible Intel Galileo. 604 605config X86_INTEL_LPSS 606 bool "Intel Low Power Subsystem Support" 607 depends on X86 && ACPI 608 select COMMON_CLK 609 select PINCTRL 610 select IOSF_MBI 611 ---help--- 612 Select to build support for Intel Low Power Subsystem such as 613 found on Intel Lynxpoint PCH. Selecting this option enables 614 things like clock tree (common clock framework) and pincontrol 615 which are needed by the LPSS peripheral drivers. 616 617config X86_AMD_PLATFORM_DEVICE 618 bool "AMD ACPI2Platform devices support" 619 depends on ACPI 620 select COMMON_CLK 621 select PINCTRL 622 ---help--- 623 Select to interpret AMD specific ACPI device to platform device 624 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 625 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 626 implemented under PINCTRL subsystem. 627 628config IOSF_MBI 629 tristate "Intel SoC IOSF Sideband support for SoC platforms" 630 depends on PCI 631 ---help--- 632 This option enables sideband register access support for Intel SoC 633 platforms. On these platforms the IOSF sideband is used in lieu of 634 MSR's for some register accesses, mostly but not limited to thermal 635 and power. Drivers may query the availability of this device to 636 determine if they need the sideband in order to work on these 637 platforms. The sideband is available on the following SoC products. 638 This list is not meant to be exclusive. 639 - BayTrail 640 - Braswell 641 - Quark 642 643 You should say Y if you are running a kernel on one of these SoC's. 644 645config IOSF_MBI_DEBUG 646 bool "Enable IOSF sideband access through debugfs" 647 depends on IOSF_MBI && DEBUG_FS 648 ---help--- 649 Select this option to expose the IOSF sideband access registers (MCR, 650 MDR, MCRX) through debugfs to write and read register information from 651 different units on the SoC. This is most useful for obtaining device 652 state information for debug and analysis. As this is a general access 653 mechanism, users of this option would have specific knowledge of the 654 device they want to access. 655 656 If you don't require the option or are in doubt, say N. 657 658config X86_RDC321X 659 bool "RDC R-321x SoC" 660 depends on X86_32 661 depends on X86_EXTENDED_PLATFORM 662 select M486 663 select X86_REBOOTFIXUPS 664 ---help--- 665 This option is needed for RDC R-321x system-on-chip, also known 666 as R-8610-(G). 667 If you don't have one of these chips, you should say N here. 668 669config X86_32_NON_STANDARD 670 bool "Support non-standard 32-bit SMP architectures" 671 depends on X86_32 && SMP 672 depends on X86_EXTENDED_PLATFORM 673 ---help--- 674 This option compiles in the bigsmp and STA2X11 default 675 subarchitectures. It is intended for a generic binary 676 kernel. If you select them all, kernel will probe it one by 677 one and will fallback to default. 678 679# Alphabetically sorted list of Non standard 32 bit platforms 680 681config X86_SUPPORTS_MEMORY_FAILURE 682 def_bool y 683 # MCE code calls memory_failure(): 684 depends on X86_MCE 685 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 686 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 687 depends on X86_64 || !SPARSEMEM 688 select ARCH_SUPPORTS_MEMORY_FAILURE 689 690config STA2X11 691 bool "STA2X11 Companion Chip Support" 692 depends on X86_32_NON_STANDARD && PCI 693 select X86_DEV_DMA_OPS 694 select X86_DMA_REMAP 695 select SWIOTLB 696 select MFD_STA2X11 697 select GPIOLIB 698 default n 699 ---help--- 700 This adds support for boards based on the STA2X11 IO-Hub, 701 a.k.a. "ConneXt". The chip is used in place of the standard 702 PC chipset, so all "standard" peripherals are missing. If this 703 option is selected the kernel will still be able to boot on 704 standard PC machines. 705 706config X86_32_IRIS 707 tristate "Eurobraille/Iris poweroff module" 708 depends on X86_32 709 ---help--- 710 The Iris machines from EuroBraille do not have APM or ACPI support 711 to shut themselves down properly. A special I/O sequence is 712 needed to do so, which is what this module does at 713 kernel shutdown. 714 715 This is only for Iris machines from EuroBraille. 716 717 If unused, say N. 718 719config SCHED_OMIT_FRAME_POINTER 720 def_bool y 721 prompt "Single-depth WCHAN output" 722 depends on X86 723 ---help--- 724 Calculate simpler /proc/<PID>/wchan values. If this option 725 is disabled then wchan values will recurse back to the 726 caller function. This provides more accurate wchan values, 727 at the expense of slightly more scheduling overhead. 728 729 If in doubt, say "Y". 730 731menuconfig HYPERVISOR_GUEST 732 bool "Linux guest support" 733 ---help--- 734 Say Y here to enable options for running Linux under various hyper- 735 visors. This option enables basic hypervisor detection and platform 736 setup. 737 738 If you say N, all options in this submenu will be skipped and 739 disabled, and Linux guest support won't be built in. 740 741if HYPERVISOR_GUEST 742 743config PARAVIRT 744 bool "Enable paravirtualization code" 745 ---help--- 746 This changes the kernel so it can modify itself when it is run 747 under a hypervisor, potentially improving performance significantly 748 over full virtualization. However, when run without a hypervisor 749 the kernel is theoretically slower and slightly larger. 750 751config PARAVIRT_DEBUG 752 bool "paravirt-ops debugging" 753 depends on PARAVIRT && DEBUG_KERNEL 754 ---help--- 755 Enable to debug paravirt_ops internals. Specifically, BUG if 756 a paravirt_op is missing when it is called. 757 758config PARAVIRT_SPINLOCKS 759 bool "Paravirtualization layer for spinlocks" 760 depends on PARAVIRT && SMP 761 ---help--- 762 Paravirtualized spinlocks allow a pvops backend to replace the 763 spinlock implementation with something virtualization-friendly 764 (for example, block the virtual CPU rather than spinning). 765 766 It has a minimal impact on native kernels and gives a nice performance 767 benefit on paravirtualized KVM / Xen kernels. 768 769 If you are unsure how to answer this question, answer Y. 770 771config QUEUED_LOCK_STAT 772 bool "Paravirt queued spinlock statistics" 773 depends on PARAVIRT_SPINLOCKS && DEBUG_FS 774 ---help--- 775 Enable the collection of statistical data on the slowpath 776 behavior of paravirtualized queued spinlocks and report 777 them on debugfs. 778 779source "arch/x86/xen/Kconfig" 780 781config KVM_GUEST 782 bool "KVM Guest support (including kvmclock)" 783 depends on PARAVIRT 784 select PARAVIRT_CLOCK 785 default y 786 ---help--- 787 This option enables various optimizations for running under the KVM 788 hypervisor. It includes a paravirtualized clock, so that instead 789 of relying on a PIT (or probably other) emulation by the 790 underlying device model, the host provides the guest with 791 timing infrastructure such as time of day, and system time 792 793config KVM_DEBUG_FS 794 bool "Enable debug information for KVM Guests in debugfs" 795 depends on KVM_GUEST && DEBUG_FS 796 default n 797 ---help--- 798 This option enables collection of various statistics for KVM guest. 799 Statistics are displayed in debugfs filesystem. Enabling this option 800 may incur significant overhead. 801 802config PARAVIRT_TIME_ACCOUNTING 803 bool "Paravirtual steal time accounting" 804 depends on PARAVIRT 805 default n 806 ---help--- 807 Select this option to enable fine granularity task steal time 808 accounting. Time spent executing other tasks in parallel with 809 the current vCPU is discounted from the vCPU power. To account for 810 that, there can be a small performance impact. 811 812 If in doubt, say N here. 813 814config PARAVIRT_CLOCK 815 bool 816 817config JAILHOUSE_GUEST 818 bool "Jailhouse non-root cell support" 819 depends on X86_64 && PCI 820 select X86_PM_TIMER 821 ---help--- 822 This option allows to run Linux as guest in a Jailhouse non-root 823 cell. You can leave this option disabled if you only want to start 824 Jailhouse and run Linux afterwards in the root cell. 825 826endif #HYPERVISOR_GUEST 827 828config NO_BOOTMEM 829 def_bool y 830 831source "arch/x86/Kconfig.cpu" 832 833config HPET_TIMER 834 def_bool X86_64 835 prompt "HPET Timer Support" if X86_32 836 ---help--- 837 Use the IA-PC HPET (High Precision Event Timer) to manage 838 time in preference to the PIT and RTC, if a HPET is 839 present. 840 HPET is the next generation timer replacing legacy 8254s. 841 The HPET provides a stable time base on SMP 842 systems, unlike the TSC, but it is more expensive to access, 843 as it is off-chip. The interface used is documented 844 in the HPET spec, revision 1. 845 846 You can safely choose Y here. However, HPET will only be 847 activated if the platform and the BIOS support this feature. 848 Otherwise the 8254 will be used for timing services. 849 850 Choose N to continue using the legacy 8254 timer. 851 852config HPET_EMULATE_RTC 853 def_bool y 854 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 855 856config APB_TIMER 857 def_bool y if X86_INTEL_MID 858 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 859 select DW_APB_TIMER 860 depends on X86_INTEL_MID && SFI 861 help 862 APB timer is the replacement for 8254, HPET on X86 MID platforms. 863 The APBT provides a stable time base on SMP 864 systems, unlike the TSC, but it is more expensive to access, 865 as it is off-chip. APB timers are always running regardless of CPU 866 C states, they are used as per CPU clockevent device when possible. 867 868# Mark as expert because too many people got it wrong. 869# The code disables itself when not needed. 870config DMI 871 default y 872 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 873 bool "Enable DMI scanning" if EXPERT 874 ---help--- 875 Enabled scanning of DMI to identify machine quirks. Say Y 876 here unless you have verified that your setup is not 877 affected by entries in the DMI blacklist. Required by PNP 878 BIOS code. 879 880config GART_IOMMU 881 bool "Old AMD GART IOMMU support" 882 select SWIOTLB 883 depends on X86_64 && PCI && AMD_NB 884 ---help--- 885 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 886 GART based hardware IOMMUs. 887 888 The GART supports full DMA access for devices with 32-bit access 889 limitations, on systems with more than 3 GB. This is usually needed 890 for USB, sound, many IDE/SATA chipsets and some other devices. 891 892 Newer systems typically have a modern AMD IOMMU, supported via 893 the CONFIG_AMD_IOMMU=y config option. 894 895 In normal configurations this driver is only active when needed: 896 there's more than 3 GB of memory and the system contains a 897 32-bit limited device. 898 899 If unsure, say Y. 900 901config CALGARY_IOMMU 902 bool "IBM Calgary IOMMU support" 903 select SWIOTLB 904 depends on X86_64 && PCI 905 ---help--- 906 Support for hardware IOMMUs in IBM's xSeries x366 and x460 907 systems. Needed to run systems with more than 3GB of memory 908 properly with 32-bit PCI devices that do not support DAC 909 (Double Address Cycle). Calgary also supports bus level 910 isolation, where all DMAs pass through the IOMMU. This 911 prevents them from going anywhere except their intended 912 destination. This catches hard-to-find kernel bugs and 913 mis-behaving drivers and devices that do not use the DMA-API 914 properly to set up their DMA buffers. The IOMMU can be 915 turned off at boot time with the iommu=off parameter. 916 Normally the kernel will make the right choice by itself. 917 If unsure, say Y. 918 919config CALGARY_IOMMU_ENABLED_BY_DEFAULT 920 def_bool y 921 prompt "Should Calgary be enabled by default?" 922 depends on CALGARY_IOMMU 923 ---help--- 924 Should Calgary be enabled by default? if you choose 'y', Calgary 925 will be used (if it exists). If you choose 'n', Calgary will not be 926 used even if it exists. If you choose 'n' and would like to use 927 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 928 If unsure, say Y. 929 930# need this always selected by IOMMU for the VIA workaround 931config SWIOTLB 932 def_bool y if X86_64 933 ---help--- 934 Support for software bounce buffers used on x86-64 systems 935 which don't have a hardware IOMMU. Using this PCI devices 936 which can only access 32-bits of memory can be used on systems 937 with more than 3 GB of memory. 938 If unsure, say Y. 939 940config IOMMU_HELPER 941 def_bool y 942 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU 943 944config MAXSMP 945 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 946 depends on X86_64 && SMP && DEBUG_KERNEL 947 select CPUMASK_OFFSTACK 948 ---help--- 949 Enable maximum number of CPUS and NUMA Nodes for this architecture. 950 If unsure, say N. 951 952config NR_CPUS 953 int "Maximum number of CPUs" if SMP && !MAXSMP 954 range 2 8 if SMP && X86_32 && !X86_BIGSMP 955 range 2 64 if SMP && X86_32 && X86_BIGSMP 956 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK && X86_64 957 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64 958 default "1" if !SMP 959 default "8192" if MAXSMP 960 default "32" if SMP && X86_BIGSMP 961 default "8" if SMP && X86_32 962 default "64" if SMP 963 ---help--- 964 This allows you to specify the maximum number of CPUs which this 965 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 966 supported value is 8192, otherwise the maximum value is 512. The 967 minimum value which makes sense is 2. 968 969 This is purely to save memory - each supported CPU adds 970 approximately eight kilobytes to the kernel image. 971 972config SCHED_SMT 973 bool "SMT (Hyperthreading) scheduler support" 974 depends on SMP 975 ---help--- 976 SMT scheduler support improves the CPU scheduler's decision making 977 when dealing with Intel Pentium 4 chips with HyperThreading at a 978 cost of slightly increased overhead in some places. If unsure say 979 N here. 980 981config SCHED_MC 982 def_bool y 983 prompt "Multi-core scheduler support" 984 depends on SMP 985 ---help--- 986 Multi-core scheduler support improves the CPU scheduler's decision 987 making when dealing with multi-core CPU chips at a cost of slightly 988 increased overhead in some places. If unsure say N here. 989 990config SCHED_MC_PRIO 991 bool "CPU core priorities scheduler support" 992 depends on SCHED_MC && CPU_SUP_INTEL 993 select X86_INTEL_PSTATE 994 select CPU_FREQ 995 default y 996 ---help--- 997 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 998 core ordering determined at manufacturing time, which allows 999 certain cores to reach higher turbo frequencies (when running 1000 single threaded workloads) than others. 1001 1002 Enabling this kernel feature teaches the scheduler about 1003 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1004 scheduler's CPU selection logic accordingly, so that higher 1005 overall system performance can be achieved. 1006 1007 This feature will have no effect on CPUs without this feature. 1008 1009 If unsure say Y here. 1010 1011source "kernel/Kconfig.preempt" 1012 1013config UP_LATE_INIT 1014 def_bool y 1015 depends on !SMP && X86_LOCAL_APIC 1016 1017config X86_UP_APIC 1018 bool "Local APIC support on uniprocessors" if !PCI_MSI 1019 default PCI_MSI 1020 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1021 ---help--- 1022 A local APIC (Advanced Programmable Interrupt Controller) is an 1023 integrated interrupt controller in the CPU. If you have a single-CPU 1024 system which has a processor with a local APIC, you can say Y here to 1025 enable and use it. If you say Y here even though your machine doesn't 1026 have a local APIC, then the kernel will still run with no slowdown at 1027 all. The local APIC supports CPU-generated self-interrupts (timer, 1028 performance counters), and the NMI watchdog which detects hard 1029 lockups. 1030 1031config X86_UP_IOAPIC 1032 bool "IO-APIC support on uniprocessors" 1033 depends on X86_UP_APIC 1034 ---help--- 1035 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1036 SMP-capable replacement for PC-style interrupt controllers. Most 1037 SMP systems and many recent uniprocessor systems have one. 1038 1039 If you have a single-CPU system with an IO-APIC, you can say Y here 1040 to use it. If you say Y here even though your machine doesn't have 1041 an IO-APIC, then the kernel will still run with no slowdown at all. 1042 1043config X86_LOCAL_APIC 1044 def_bool y 1045 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1046 select IRQ_DOMAIN_HIERARCHY 1047 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1048 1049config X86_IO_APIC 1050 def_bool y 1051 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1052 1053config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1054 bool "Reroute for broken boot IRQs" 1055 depends on X86_IO_APIC 1056 ---help--- 1057 This option enables a workaround that fixes a source of 1058 spurious interrupts. This is recommended when threaded 1059 interrupt handling is used on systems where the generation of 1060 superfluous "boot interrupts" cannot be disabled. 1061 1062 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1063 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1064 kernel does during interrupt handling). On chipsets where this 1065 boot IRQ generation cannot be disabled, this workaround keeps 1066 the original IRQ line masked so that only the equivalent "boot 1067 IRQ" is delivered to the CPUs. The workaround also tells the 1068 kernel to set up the IRQ handler on the boot IRQ line. In this 1069 way only one interrupt is delivered to the kernel. Otherwise 1070 the spurious second interrupt may cause the kernel to bring 1071 down (vital) interrupt lines. 1072 1073 Only affects "broken" chipsets. Interrupt sharing may be 1074 increased on these systems. 1075 1076config X86_MCE 1077 bool "Machine Check / overheating reporting" 1078 select GENERIC_ALLOCATOR 1079 default y 1080 ---help--- 1081 Machine Check support allows the processor to notify the 1082 kernel if it detects a problem (e.g. overheating, data corruption). 1083 The action the kernel takes depends on the severity of the problem, 1084 ranging from warning messages to halting the machine. 1085 1086config X86_MCELOG_LEGACY 1087 bool "Support for deprecated /dev/mcelog character device" 1088 depends on X86_MCE 1089 ---help--- 1090 Enable support for /dev/mcelog which is needed by the old mcelog 1091 userspace logging daemon. Consider switching to the new generation 1092 rasdaemon solution. 1093 1094config X86_MCE_INTEL 1095 def_bool y 1096 prompt "Intel MCE features" 1097 depends on X86_MCE && X86_LOCAL_APIC 1098 ---help--- 1099 Additional support for intel specific MCE features such as 1100 the thermal monitor. 1101 1102config X86_MCE_AMD 1103 def_bool y 1104 prompt "AMD MCE features" 1105 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1106 ---help--- 1107 Additional support for AMD specific MCE features such as 1108 the DRAM Error Threshold. 1109 1110config X86_ANCIENT_MCE 1111 bool "Support for old Pentium 5 / WinChip machine checks" 1112 depends on X86_32 && X86_MCE 1113 ---help--- 1114 Include support for machine check handling on old Pentium 5 or WinChip 1115 systems. These typically need to be enabled explicitly on the command 1116 line. 1117 1118config X86_MCE_THRESHOLD 1119 depends on X86_MCE_AMD || X86_MCE_INTEL 1120 def_bool y 1121 1122config X86_MCE_INJECT 1123 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1124 tristate "Machine check injector support" 1125 ---help--- 1126 Provide support for injecting machine checks for testing purposes. 1127 If you don't know what a machine check is and you don't do kernel 1128 QA it is safe to say n. 1129 1130config X86_THERMAL_VECTOR 1131 def_bool y 1132 depends on X86_MCE_INTEL 1133 1134source "arch/x86/events/Kconfig" 1135 1136config X86_LEGACY_VM86 1137 bool "Legacy VM86 support" 1138 default n 1139 depends on X86_32 1140 ---help--- 1141 This option allows user programs to put the CPU into V8086 1142 mode, which is an 80286-era approximation of 16-bit real mode. 1143 1144 Some very old versions of X and/or vbetool require this option 1145 for user mode setting. Similarly, DOSEMU will use it if 1146 available to accelerate real mode DOS programs. However, any 1147 recent version of DOSEMU, X, or vbetool should be fully 1148 functional even without kernel VM86 support, as they will all 1149 fall back to software emulation. Nevertheless, if you are using 1150 a 16-bit DOS program where 16-bit performance matters, vm86 1151 mode might be faster than emulation and you might want to 1152 enable this option. 1153 1154 Note that any app that works on a 64-bit kernel is unlikely to 1155 need this option, as 64-bit kernels don't, and can't, support 1156 V8086 mode. This option is also unrelated to 16-bit protected 1157 mode and is not needed to run most 16-bit programs under Wine. 1158 1159 Enabling this option increases the complexity of the kernel 1160 and slows down exception handling a tiny bit. 1161 1162 If unsure, say N here. 1163 1164config VM86 1165 bool 1166 default X86_LEGACY_VM86 1167 1168config X86_16BIT 1169 bool "Enable support for 16-bit segments" if EXPERT 1170 default y 1171 depends on MODIFY_LDT_SYSCALL 1172 ---help--- 1173 This option is required by programs like Wine to run 16-bit 1174 protected mode legacy code on x86 processors. Disabling 1175 this option saves about 300 bytes on i386, or around 6K text 1176 plus 16K runtime memory on x86-64, 1177 1178config X86_ESPFIX32 1179 def_bool y 1180 depends on X86_16BIT && X86_32 1181 1182config X86_ESPFIX64 1183 def_bool y 1184 depends on X86_16BIT && X86_64 1185 1186config X86_VSYSCALL_EMULATION 1187 bool "Enable vsyscall emulation" if EXPERT 1188 default y 1189 depends on X86_64 1190 ---help--- 1191 This enables emulation of the legacy vsyscall page. Disabling 1192 it is roughly equivalent to booting with vsyscall=none, except 1193 that it will also disable the helpful warning if a program 1194 tries to use a vsyscall. With this option set to N, offending 1195 programs will just segfault, citing addresses of the form 1196 0xffffffffff600?00. 1197 1198 This option is required by many programs built before 2013, and 1199 care should be used even with newer programs if set to N. 1200 1201 Disabling this option saves about 7K of kernel size and 1202 possibly 4K of additional runtime pagetable memory. 1203 1204config TOSHIBA 1205 tristate "Toshiba Laptop support" 1206 depends on X86_32 1207 ---help--- 1208 This adds a driver to safely access the System Management Mode of 1209 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1210 not work on models with a Phoenix BIOS. The System Management Mode 1211 is used to set the BIOS and power saving options on Toshiba portables. 1212 1213 For information on utilities to make use of this driver see the 1214 Toshiba Linux utilities web site at: 1215 <http://www.buzzard.org.uk/toshiba/>. 1216 1217 Say Y if you intend to run this kernel on a Toshiba portable. 1218 Say N otherwise. 1219 1220config I8K 1221 tristate "Dell i8k legacy laptop support" 1222 select HWMON 1223 select SENSORS_DELL_SMM 1224 ---help--- 1225 This option enables legacy /proc/i8k userspace interface in hwmon 1226 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1227 temperature and allows controlling fan speeds of Dell laptops via 1228 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1229 it reports also power and hotkey status. For fan speed control is 1230 needed userspace package i8kutils. 1231 1232 Say Y if you intend to run this kernel on old Dell laptops or want to 1233 use userspace package i8kutils. 1234 Say N otherwise. 1235 1236config X86_REBOOTFIXUPS 1237 bool "Enable X86 board specific fixups for reboot" 1238 depends on X86_32 1239 ---help--- 1240 This enables chipset and/or board specific fixups to be done 1241 in order to get reboot to work correctly. This is only needed on 1242 some combinations of hardware and BIOS. The symptom, for which 1243 this config is intended, is when reboot ends with a stalled/hung 1244 system. 1245 1246 Currently, the only fixup is for the Geode machines using 1247 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1248 1249 Say Y if you want to enable the fixup. Currently, it's safe to 1250 enable this option even if you don't need it. 1251 Say N otherwise. 1252 1253config MICROCODE 1254 bool "CPU microcode loading support" 1255 default y 1256 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1257 select FW_LOADER 1258 ---help--- 1259 If you say Y here, you will be able to update the microcode on 1260 Intel and AMD processors. The Intel support is for the IA32 family, 1261 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1262 AMD support is for families 0x10 and later. You will obviously need 1263 the actual microcode binary data itself which is not shipped with 1264 the Linux kernel. 1265 1266 The preferred method to load microcode from a detached initrd is described 1267 in Documentation/x86/early-microcode.txt. For that you need to enable 1268 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1269 initrd for microcode blobs. 1270 1271 In addition, you can build the microcode into the kernel. For that you 1272 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1273 config option. 1274 1275config MICROCODE_INTEL 1276 bool "Intel microcode loading support" 1277 depends on MICROCODE 1278 default MICROCODE 1279 select FW_LOADER 1280 ---help--- 1281 This options enables microcode patch loading support for Intel 1282 processors. 1283 1284 For the current Intel microcode data package go to 1285 <https://downloadcenter.intel.com> and search for 1286 'Linux Processor Microcode Data File'. 1287 1288config MICROCODE_AMD 1289 bool "AMD microcode loading support" 1290 depends on MICROCODE 1291 select FW_LOADER 1292 ---help--- 1293 If you select this option, microcode patch loading support for AMD 1294 processors will be enabled. 1295 1296config MICROCODE_OLD_INTERFACE 1297 def_bool y 1298 depends on MICROCODE 1299 1300config X86_MSR 1301 tristate "/dev/cpu/*/msr - Model-specific register support" 1302 ---help--- 1303 This device gives privileged processes access to the x86 1304 Model-Specific Registers (MSRs). It is a character device with 1305 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1306 MSR accesses are directed to a specific CPU on multi-processor 1307 systems. 1308 1309config X86_CPUID 1310 tristate "/dev/cpu/*/cpuid - CPU information support" 1311 ---help--- 1312 This device gives processes access to the x86 CPUID instruction to 1313 be executed on a specific processor. It is a character device 1314 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1315 /dev/cpu/31/cpuid. 1316 1317choice 1318 prompt "High Memory Support" 1319 default HIGHMEM4G 1320 depends on X86_32 1321 1322config NOHIGHMEM 1323 bool "off" 1324 ---help--- 1325 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1326 However, the address space of 32-bit x86 processors is only 4 1327 Gigabytes large. That means that, if you have a large amount of 1328 physical memory, not all of it can be "permanently mapped" by the 1329 kernel. The physical memory that's not permanently mapped is called 1330 "high memory". 1331 1332 If you are compiling a kernel which will never run on a machine with 1333 more than 1 Gigabyte total physical RAM, answer "off" here (default 1334 choice and suitable for most users). This will result in a "3GB/1GB" 1335 split: 3GB are mapped so that each process sees a 3GB virtual memory 1336 space and the remaining part of the 4GB virtual memory space is used 1337 by the kernel to permanently map as much physical memory as 1338 possible. 1339 1340 If the machine has between 1 and 4 Gigabytes physical RAM, then 1341 answer "4GB" here. 1342 1343 If more than 4 Gigabytes is used then answer "64GB" here. This 1344 selection turns Intel PAE (Physical Address Extension) mode on. 1345 PAE implements 3-level paging on IA32 processors. PAE is fully 1346 supported by Linux, PAE mode is implemented on all recent Intel 1347 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1348 then the kernel will not boot on CPUs that don't support PAE! 1349 1350 The actual amount of total physical memory will either be 1351 auto detected or can be forced by using a kernel command line option 1352 such as "mem=256M". (Try "man bootparam" or see the documentation of 1353 your boot loader (lilo or loadlin) about how to pass options to the 1354 kernel at boot time.) 1355 1356 If unsure, say "off". 1357 1358config HIGHMEM4G 1359 bool "4GB" 1360 ---help--- 1361 Select this if you have a 32-bit processor and between 1 and 4 1362 gigabytes of physical RAM. 1363 1364config HIGHMEM64G 1365 bool "64GB" 1366 depends on !M486 1367 select X86_PAE 1368 ---help--- 1369 Select this if you have a 32-bit processor and more than 4 1370 gigabytes of physical RAM. 1371 1372endchoice 1373 1374choice 1375 prompt "Memory split" if EXPERT 1376 default VMSPLIT_3G 1377 depends on X86_32 1378 ---help--- 1379 Select the desired split between kernel and user memory. 1380 1381 If the address range available to the kernel is less than the 1382 physical memory installed, the remaining memory will be available 1383 as "high memory". Accessing high memory is a little more costly 1384 than low memory, as it needs to be mapped into the kernel first. 1385 Note that increasing the kernel address space limits the range 1386 available to user programs, making the address space there 1387 tighter. Selecting anything other than the default 3G/1G split 1388 will also likely make your kernel incompatible with binary-only 1389 kernel modules. 1390 1391 If you are not absolutely sure what you are doing, leave this 1392 option alone! 1393 1394 config VMSPLIT_3G 1395 bool "3G/1G user/kernel split" 1396 config VMSPLIT_3G_OPT 1397 depends on !X86_PAE 1398 bool "3G/1G user/kernel split (for full 1G low memory)" 1399 config VMSPLIT_2G 1400 bool "2G/2G user/kernel split" 1401 config VMSPLIT_2G_OPT 1402 depends on !X86_PAE 1403 bool "2G/2G user/kernel split (for full 2G low memory)" 1404 config VMSPLIT_1G 1405 bool "1G/3G user/kernel split" 1406endchoice 1407 1408config PAGE_OFFSET 1409 hex 1410 default 0xB0000000 if VMSPLIT_3G_OPT 1411 default 0x80000000 if VMSPLIT_2G 1412 default 0x78000000 if VMSPLIT_2G_OPT 1413 default 0x40000000 if VMSPLIT_1G 1414 default 0xC0000000 1415 depends on X86_32 1416 1417config HIGHMEM 1418 def_bool y 1419 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1420 1421config X86_PAE 1422 bool "PAE (Physical Address Extension) Support" 1423 depends on X86_32 && !HIGHMEM4G 1424 select SWIOTLB 1425 ---help--- 1426 PAE is required for NX support, and furthermore enables 1427 larger swapspace support for non-overcommit purposes. It 1428 has the cost of more pagetable lookup overhead, and also 1429 consumes more pagetable space per process. 1430 1431config X86_5LEVEL 1432 bool "Enable 5-level page tables support" 1433 depends on X86_64 1434 ---help--- 1435 5-level paging enables access to larger address space: 1436 upto 128 PiB of virtual address space and 4 PiB of 1437 physical address space. 1438 1439 It will be supported by future Intel CPUs. 1440 1441 Note: a kernel with this option enabled can only be booted 1442 on machines that support the feature. 1443 1444 See Documentation/x86/x86_64/5level-paging.txt for more 1445 information. 1446 1447 Say N if unsure. 1448 1449config ARCH_PHYS_ADDR_T_64BIT 1450 def_bool y 1451 depends on X86_64 || X86_PAE 1452 1453config ARCH_DMA_ADDR_T_64BIT 1454 def_bool y 1455 depends on X86_64 || HIGHMEM64G 1456 1457config X86_DIRECT_GBPAGES 1458 def_bool y 1459 depends on X86_64 && !DEBUG_PAGEALLOC 1460 ---help--- 1461 Certain kernel features effectively disable kernel 1462 linear 1 GB mappings (even if the CPU otherwise 1463 supports them), so don't confuse the user by printing 1464 that we have them enabled. 1465 1466config ARCH_HAS_MEM_ENCRYPT 1467 def_bool y 1468 1469config AMD_MEM_ENCRYPT 1470 bool "AMD Secure Memory Encryption (SME) support" 1471 depends on X86_64 && CPU_SUP_AMD 1472 ---help--- 1473 Say yes to enable support for the encryption of system memory. 1474 This requires an AMD processor that supports Secure Memory 1475 Encryption (SME). 1476 1477config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1478 bool "Activate AMD Secure Memory Encryption (SME) by default" 1479 default y 1480 depends on AMD_MEM_ENCRYPT 1481 ---help--- 1482 Say yes to have system memory encrypted by default if running on 1483 an AMD processor that supports Secure Memory Encryption (SME). 1484 1485 If set to Y, then the encryption of system memory can be 1486 deactivated with the mem_encrypt=off command line option. 1487 1488 If set to N, then the encryption of system memory can be 1489 activated with the mem_encrypt=on command line option. 1490 1491config ARCH_USE_MEMREMAP_PROT 1492 def_bool y 1493 depends on AMD_MEM_ENCRYPT 1494 1495# Common NUMA Features 1496config NUMA 1497 bool "Numa Memory Allocation and Scheduler Support" 1498 depends on SMP 1499 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1500 default y if X86_BIGSMP 1501 ---help--- 1502 Enable NUMA (Non Uniform Memory Access) support. 1503 1504 The kernel will try to allocate memory used by a CPU on the 1505 local memory controller of the CPU and add some more 1506 NUMA awareness to the kernel. 1507 1508 For 64-bit this is recommended if the system is Intel Core i7 1509 (or later), AMD Opteron, or EM64T NUMA. 1510 1511 For 32-bit this is only needed if you boot a 32-bit 1512 kernel on a 64-bit NUMA platform. 1513 1514 Otherwise, you should say N. 1515 1516config AMD_NUMA 1517 def_bool y 1518 prompt "Old style AMD Opteron NUMA detection" 1519 depends on X86_64 && NUMA && PCI 1520 ---help--- 1521 Enable AMD NUMA node topology detection. You should say Y here if 1522 you have a multi processor AMD system. This uses an old method to 1523 read the NUMA configuration directly from the builtin Northbridge 1524 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1525 which also takes priority if both are compiled in. 1526 1527config X86_64_ACPI_NUMA 1528 def_bool y 1529 prompt "ACPI NUMA detection" 1530 depends on X86_64 && NUMA && ACPI && PCI 1531 select ACPI_NUMA 1532 ---help--- 1533 Enable ACPI SRAT based node topology detection. 1534 1535# Some NUMA nodes have memory ranges that span 1536# other nodes. Even though a pfn is valid and 1537# between a node's start and end pfns, it may not 1538# reside on that node. See memmap_init_zone() 1539# for details. 1540config NODES_SPAN_OTHER_NODES 1541 def_bool y 1542 depends on X86_64_ACPI_NUMA 1543 1544config NUMA_EMU 1545 bool "NUMA emulation" 1546 depends on NUMA 1547 ---help--- 1548 Enable NUMA emulation. A flat machine will be split 1549 into virtual nodes when booted with "numa=fake=N", where N is the 1550 number of nodes. This is only useful for debugging. 1551 1552config NODES_SHIFT 1553 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1554 range 1 10 1555 default "10" if MAXSMP 1556 default "6" if X86_64 1557 default "3" 1558 depends on NEED_MULTIPLE_NODES 1559 ---help--- 1560 Specify the maximum number of NUMA Nodes available on the target 1561 system. Increases memory reserved to accommodate various tables. 1562 1563config ARCH_HAVE_MEMORY_PRESENT 1564 def_bool y 1565 depends on X86_32 && DISCONTIGMEM 1566 1567config NEED_NODE_MEMMAP_SIZE 1568 def_bool y 1569 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM) 1570 1571config ARCH_FLATMEM_ENABLE 1572 def_bool y 1573 depends on X86_32 && !NUMA 1574 1575config ARCH_DISCONTIGMEM_ENABLE 1576 def_bool y 1577 depends on NUMA && X86_32 1578 1579config ARCH_DISCONTIGMEM_DEFAULT 1580 def_bool y 1581 depends on NUMA && X86_32 1582 1583config ARCH_SPARSEMEM_ENABLE 1584 def_bool y 1585 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1586 select SPARSEMEM_STATIC if X86_32 1587 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1588 1589config ARCH_SPARSEMEM_DEFAULT 1590 def_bool y 1591 depends on X86_64 1592 1593config ARCH_SELECT_MEMORY_MODEL 1594 def_bool y 1595 depends on ARCH_SPARSEMEM_ENABLE 1596 1597config ARCH_MEMORY_PROBE 1598 bool "Enable sysfs memory/probe interface" 1599 depends on X86_64 && MEMORY_HOTPLUG 1600 help 1601 This option enables a sysfs memory/probe interface for testing. 1602 See Documentation/memory-hotplug.txt for more information. 1603 If you are unsure how to answer this question, answer N. 1604 1605config ARCH_PROC_KCORE_TEXT 1606 def_bool y 1607 depends on X86_64 && PROC_KCORE 1608 1609config ILLEGAL_POINTER_VALUE 1610 hex 1611 default 0 if X86_32 1612 default 0xdead000000000000 if X86_64 1613 1614source "mm/Kconfig" 1615 1616config X86_PMEM_LEGACY_DEVICE 1617 bool 1618 1619config X86_PMEM_LEGACY 1620 tristate "Support non-standard NVDIMMs and ADR protected memory" 1621 depends on PHYS_ADDR_T_64BIT 1622 depends on BLK_DEV 1623 select X86_PMEM_LEGACY_DEVICE 1624 select LIBNVDIMM 1625 help 1626 Treat memory marked using the non-standard e820 type of 12 as used 1627 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1628 The kernel will offer these regions to the 'pmem' driver so 1629 they can be used for persistent storage. 1630 1631 Say Y if unsure. 1632 1633config HIGHPTE 1634 bool "Allocate 3rd-level pagetables from highmem" 1635 depends on HIGHMEM 1636 ---help--- 1637 The VM uses one page table entry for each page of physical memory. 1638 For systems with a lot of RAM, this can be wasteful of precious 1639 low memory. Setting this option will put user-space page table 1640 entries in high memory. 1641 1642config X86_CHECK_BIOS_CORRUPTION 1643 bool "Check for low memory corruption" 1644 ---help--- 1645 Periodically check for memory corruption in low memory, which 1646 is suspected to be caused by BIOS. Even when enabled in the 1647 configuration, it is disabled at runtime. Enable it by 1648 setting "memory_corruption_check=1" on the kernel command 1649 line. By default it scans the low 64k of memory every 60 1650 seconds; see the memory_corruption_check_size and 1651 memory_corruption_check_period parameters in 1652 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1653 1654 When enabled with the default parameters, this option has 1655 almost no overhead, as it reserves a relatively small amount 1656 of memory and scans it infrequently. It both detects corruption 1657 and prevents it from affecting the running system. 1658 1659 It is, however, intended as a diagnostic tool; if repeatable 1660 BIOS-originated corruption always affects the same memory, 1661 you can use memmap= to prevent the kernel from using that 1662 memory. 1663 1664config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1665 bool "Set the default setting of memory_corruption_check" 1666 depends on X86_CHECK_BIOS_CORRUPTION 1667 default y 1668 ---help--- 1669 Set whether the default state of memory_corruption_check is 1670 on or off. 1671 1672config X86_RESERVE_LOW 1673 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1674 default 64 1675 range 4 640 1676 ---help--- 1677 Specify the amount of low memory to reserve for the BIOS. 1678 1679 The first page contains BIOS data structures that the kernel 1680 must not use, so that page must always be reserved. 1681 1682 By default we reserve the first 64K of physical RAM, as a 1683 number of BIOSes are known to corrupt that memory range 1684 during events such as suspend/resume or monitor cable 1685 insertion, so it must not be used by the kernel. 1686 1687 You can set this to 4 if you are absolutely sure that you 1688 trust the BIOS to get all its memory reservations and usages 1689 right. If you know your BIOS have problems beyond the 1690 default 64K area, you can set this to 640 to avoid using the 1691 entire low memory range. 1692 1693 If you have doubts about the BIOS (e.g. suspend/resume does 1694 not work or there's kernel crashes after certain hardware 1695 hotplug events) then you might want to enable 1696 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1697 typical corruption patterns. 1698 1699 Leave this to the default value of 64 if you are unsure. 1700 1701config MATH_EMULATION 1702 bool 1703 depends on MODIFY_LDT_SYSCALL 1704 prompt "Math emulation" if X86_32 1705 ---help--- 1706 Linux can emulate a math coprocessor (used for floating point 1707 operations) if you don't have one. 486DX and Pentium processors have 1708 a math coprocessor built in, 486SX and 386 do not, unless you added 1709 a 487DX or 387, respectively. (The messages during boot time can 1710 give you some hints here ["man dmesg"].) Everyone needs either a 1711 coprocessor or this emulation. 1712 1713 If you don't have a math coprocessor, you need to say Y here; if you 1714 say Y here even though you have a coprocessor, the coprocessor will 1715 be used nevertheless. (This behavior can be changed with the kernel 1716 command line option "no387", which comes handy if your coprocessor 1717 is broken. Try "man bootparam" or see the documentation of your boot 1718 loader (lilo or loadlin) about how to pass options to the kernel at 1719 boot time.) This means that it is a good idea to say Y here if you 1720 intend to use this kernel on different machines. 1721 1722 More information about the internals of the Linux math coprocessor 1723 emulation can be found in <file:arch/x86/math-emu/README>. 1724 1725 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1726 kernel, it won't hurt. 1727 1728config MTRR 1729 def_bool y 1730 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1731 ---help--- 1732 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1733 the Memory Type Range Registers (MTRRs) may be used to control 1734 processor access to memory ranges. This is most useful if you have 1735 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1736 allows bus write transfers to be combined into a larger transfer 1737 before bursting over the PCI/AGP bus. This can increase performance 1738 of image write operations 2.5 times or more. Saying Y here creates a 1739 /proc/mtrr file which may be used to manipulate your processor's 1740 MTRRs. Typically the X server should use this. 1741 1742 This code has a reasonably generic interface so that similar 1743 control registers on other processors can be easily supported 1744 as well: 1745 1746 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1747 Registers (ARRs) which provide a similar functionality to MTRRs. For 1748 these, the ARRs are used to emulate the MTRRs. 1749 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1750 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1751 write-combining. All of these processors are supported by this code 1752 and it makes sense to say Y here if you have one of them. 1753 1754 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1755 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1756 can lead to all sorts of problems, so it's good to say Y here. 1757 1758 You can safely say Y even if your machine doesn't have MTRRs, you'll 1759 just add about 9 KB to your kernel. 1760 1761 See <file:Documentation/x86/mtrr.txt> for more information. 1762 1763config MTRR_SANITIZER 1764 def_bool y 1765 prompt "MTRR cleanup support" 1766 depends on MTRR 1767 ---help--- 1768 Convert MTRR layout from continuous to discrete, so X drivers can 1769 add writeback entries. 1770 1771 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1772 The largest mtrr entry size for a continuous block can be set with 1773 mtrr_chunk_size. 1774 1775 If unsure, say Y. 1776 1777config MTRR_SANITIZER_ENABLE_DEFAULT 1778 int "MTRR cleanup enable value (0-1)" 1779 range 0 1 1780 default "0" 1781 depends on MTRR_SANITIZER 1782 ---help--- 1783 Enable mtrr cleanup default value 1784 1785config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1786 int "MTRR cleanup spare reg num (0-7)" 1787 range 0 7 1788 default "1" 1789 depends on MTRR_SANITIZER 1790 ---help--- 1791 mtrr cleanup spare entries default, it can be changed via 1792 mtrr_spare_reg_nr=N on the kernel command line. 1793 1794config X86_PAT 1795 def_bool y 1796 prompt "x86 PAT support" if EXPERT 1797 depends on MTRR 1798 ---help--- 1799 Use PAT attributes to setup page level cache control. 1800 1801 PATs are the modern equivalents of MTRRs and are much more 1802 flexible than MTRRs. 1803 1804 Say N here if you see bootup problems (boot crash, boot hang, 1805 spontaneous reboots) or a non-working video driver. 1806 1807 If unsure, say Y. 1808 1809config ARCH_USES_PG_UNCACHED 1810 def_bool y 1811 depends on X86_PAT 1812 1813config ARCH_RANDOM 1814 def_bool y 1815 prompt "x86 architectural random number generator" if EXPERT 1816 ---help--- 1817 Enable the x86 architectural RDRAND instruction 1818 (Intel Bull Mountain technology) to generate random numbers. 1819 If supported, this is a high bandwidth, cryptographically 1820 secure hardware random number generator. 1821 1822config X86_SMAP 1823 def_bool y 1824 prompt "Supervisor Mode Access Prevention" if EXPERT 1825 ---help--- 1826 Supervisor Mode Access Prevention (SMAP) is a security 1827 feature in newer Intel processors. There is a small 1828 performance cost if this enabled and turned on; there is 1829 also a small increase in the kernel size if this is enabled. 1830 1831 If unsure, say Y. 1832 1833config X86_INTEL_UMIP 1834 def_bool y 1835 depends on CPU_SUP_INTEL 1836 prompt "Intel User Mode Instruction Prevention" if EXPERT 1837 ---help--- 1838 The User Mode Instruction Prevention (UMIP) is a security 1839 feature in newer Intel processors. If enabled, a general 1840 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1841 or STR instructions are executed in user mode. These instructions 1842 unnecessarily expose information about the hardware state. 1843 1844 The vast majority of applications do not use these instructions. 1845 For the very few that do, software emulation is provided in 1846 specific cases in protected and virtual-8086 modes. Emulated 1847 results are dummy. 1848 1849config X86_INTEL_MPX 1850 prompt "Intel MPX (Memory Protection Extensions)" 1851 def_bool n 1852 # Note: only available in 64-bit mode due to VMA flags shortage 1853 depends on CPU_SUP_INTEL && X86_64 1854 select ARCH_USES_HIGH_VMA_FLAGS 1855 ---help--- 1856 MPX provides hardware features that can be used in 1857 conjunction with compiler-instrumented code to check 1858 memory references. It is designed to detect buffer 1859 overflow or underflow bugs. 1860 1861 This option enables running applications which are 1862 instrumented or otherwise use MPX. It does not use MPX 1863 itself inside the kernel or to protect the kernel 1864 against bad memory references. 1865 1866 Enabling this option will make the kernel larger: 1867 ~8k of kernel text and 36 bytes of data on a 64-bit 1868 defconfig. It adds a long to the 'mm_struct' which 1869 will increase the kernel memory overhead of each 1870 process and adds some branches to paths used during 1871 exec() and munmap(). 1872 1873 For details, see Documentation/x86/intel_mpx.txt 1874 1875 If unsure, say N. 1876 1877config X86_INTEL_MEMORY_PROTECTION_KEYS 1878 prompt "Intel Memory Protection Keys" 1879 def_bool y 1880 # Note: only available in 64-bit mode 1881 depends on CPU_SUP_INTEL && X86_64 1882 select ARCH_USES_HIGH_VMA_FLAGS 1883 select ARCH_HAS_PKEYS 1884 ---help--- 1885 Memory Protection Keys provides a mechanism for enforcing 1886 page-based protections, but without requiring modification of the 1887 page tables when an application changes protection domains. 1888 1889 For details, see Documentation/x86/protection-keys.txt 1890 1891 If unsure, say y. 1892 1893config EFI 1894 bool "EFI runtime service support" 1895 depends on ACPI 1896 select UCS2_STRING 1897 select EFI_RUNTIME_WRAPPERS 1898 ---help--- 1899 This enables the kernel to use EFI runtime services that are 1900 available (such as the EFI variable services). 1901 1902 This option is only useful on systems that have EFI firmware. 1903 In addition, you should use the latest ELILO loader available 1904 at <http://elilo.sourceforge.net> in order to take advantage 1905 of EFI runtime services. However, even with this option, the 1906 resultant kernel should continue to boot on existing non-EFI 1907 platforms. 1908 1909config EFI_STUB 1910 bool "EFI stub support" 1911 depends on EFI && !X86_USE_3DNOW 1912 select RELOCATABLE 1913 ---help--- 1914 This kernel feature allows a bzImage to be loaded directly 1915 by EFI firmware without the use of a bootloader. 1916 1917 See Documentation/efi-stub.txt for more information. 1918 1919config EFI_MIXED 1920 bool "EFI mixed-mode support" 1921 depends on EFI_STUB && X86_64 1922 ---help--- 1923 Enabling this feature allows a 64-bit kernel to be booted 1924 on a 32-bit firmware, provided that your CPU supports 64-bit 1925 mode. 1926 1927 Note that it is not possible to boot a mixed-mode enabled 1928 kernel via the EFI boot stub - a bootloader that supports 1929 the EFI handover protocol must be used. 1930 1931 If unsure, say N. 1932 1933config SECCOMP 1934 def_bool y 1935 prompt "Enable seccomp to safely compute untrusted bytecode" 1936 ---help--- 1937 This kernel feature is useful for number crunching applications 1938 that may need to compute untrusted bytecode during their 1939 execution. By using pipes or other transports made available to 1940 the process as file descriptors supporting the read/write 1941 syscalls, it's possible to isolate those applications in 1942 their own address space using seccomp. Once seccomp is 1943 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1944 and the task is only allowed to execute a few safe syscalls 1945 defined by each seccomp mode. 1946 1947 If unsure, say Y. Only embedded should say N here. 1948 1949source kernel/Kconfig.hz 1950 1951config KEXEC 1952 bool "kexec system call" 1953 select KEXEC_CORE 1954 ---help--- 1955 kexec is a system call that implements the ability to shutdown your 1956 current kernel, and to start another kernel. It is like a reboot 1957 but it is independent of the system firmware. And like a reboot 1958 you can start any kernel with it, not just Linux. 1959 1960 The name comes from the similarity to the exec system call. 1961 1962 It is an ongoing process to be certain the hardware in a machine 1963 is properly shutdown, so do not be surprised if this code does not 1964 initially work for you. As of this writing the exact hardware 1965 interface is strongly in flux, so no good recommendation can be 1966 made. 1967 1968config KEXEC_FILE 1969 bool "kexec file based system call" 1970 select KEXEC_CORE 1971 select BUILD_BIN2C 1972 depends on X86_64 1973 depends on CRYPTO=y 1974 depends on CRYPTO_SHA256=y 1975 ---help--- 1976 This is new version of kexec system call. This system call is 1977 file based and takes file descriptors as system call argument 1978 for kernel and initramfs as opposed to list of segments as 1979 accepted by previous system call. 1980 1981config KEXEC_VERIFY_SIG 1982 bool "Verify kernel signature during kexec_file_load() syscall" 1983 depends on KEXEC_FILE 1984 ---help--- 1985 This option makes kernel signature verification mandatory for 1986 the kexec_file_load() syscall. 1987 1988 In addition to that option, you need to enable signature 1989 verification for the corresponding kernel image type being 1990 loaded in order for this to work. 1991 1992config KEXEC_BZIMAGE_VERIFY_SIG 1993 bool "Enable bzImage signature verification support" 1994 depends on KEXEC_VERIFY_SIG 1995 depends on SIGNED_PE_FILE_VERIFICATION 1996 select SYSTEM_TRUSTED_KEYRING 1997 ---help--- 1998 Enable bzImage signature verification support. 1999 2000config CRASH_DUMP 2001 bool "kernel crash dumps" 2002 depends on X86_64 || (X86_32 && HIGHMEM) 2003 ---help--- 2004 Generate crash dump after being started by kexec. 2005 This should be normally only set in special crash dump kernels 2006 which are loaded in the main kernel with kexec-tools into 2007 a specially reserved region and then later executed after 2008 a crash by kdump/kexec. The crash dump kernel must be compiled 2009 to a memory address not used by the main kernel or BIOS using 2010 PHYSICAL_START, or it must be built as a relocatable image 2011 (CONFIG_RELOCATABLE=y). 2012 For more details see Documentation/kdump/kdump.txt 2013 2014config KEXEC_JUMP 2015 bool "kexec jump" 2016 depends on KEXEC && HIBERNATION 2017 ---help--- 2018 Jump between original kernel and kexeced kernel and invoke 2019 code in physical address mode via KEXEC 2020 2021config PHYSICAL_START 2022 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2023 default "0x1000000" 2024 ---help--- 2025 This gives the physical address where the kernel is loaded. 2026 2027 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2028 bzImage will decompress itself to above physical address and 2029 run from there. Otherwise, bzImage will run from the address where 2030 it has been loaded by the boot loader and will ignore above physical 2031 address. 2032 2033 In normal kdump cases one does not have to set/change this option 2034 as now bzImage can be compiled as a completely relocatable image 2035 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2036 address. This option is mainly useful for the folks who don't want 2037 to use a bzImage for capturing the crash dump and want to use a 2038 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2039 to be specifically compiled to run from a specific memory area 2040 (normally a reserved region) and this option comes handy. 2041 2042 So if you are using bzImage for capturing the crash dump, 2043 leave the value here unchanged to 0x1000000 and set 2044 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2045 for capturing the crash dump change this value to start of 2046 the reserved region. In other words, it can be set based on 2047 the "X" value as specified in the "crashkernel=YM@XM" 2048 command line boot parameter passed to the panic-ed 2049 kernel. Please take a look at Documentation/kdump/kdump.txt 2050 for more details about crash dumps. 2051 2052 Usage of bzImage for capturing the crash dump is recommended as 2053 one does not have to build two kernels. Same kernel can be used 2054 as production kernel and capture kernel. Above option should have 2055 gone away after relocatable bzImage support is introduced. But it 2056 is present because there are users out there who continue to use 2057 vmlinux for dump capture. This option should go away down the 2058 line. 2059 2060 Don't change this unless you know what you are doing. 2061 2062config RELOCATABLE 2063 bool "Build a relocatable kernel" 2064 default y 2065 ---help--- 2066 This builds a kernel image that retains relocation information 2067 so it can be loaded someplace besides the default 1MB. 2068 The relocations tend to make the kernel binary about 10% larger, 2069 but are discarded at runtime. 2070 2071 One use is for the kexec on panic case where the recovery kernel 2072 must live at a different physical address than the primary 2073 kernel. 2074 2075 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2076 it has been loaded at and the compile time physical address 2077 (CONFIG_PHYSICAL_START) is used as the minimum location. 2078 2079config RANDOMIZE_BASE 2080 bool "Randomize the address of the kernel image (KASLR)" 2081 depends on RELOCATABLE 2082 default y 2083 ---help--- 2084 In support of Kernel Address Space Layout Randomization (KASLR), 2085 this randomizes the physical address at which the kernel image 2086 is decompressed and the virtual address where the kernel 2087 image is mapped, as a security feature that deters exploit 2088 attempts relying on knowledge of the location of kernel 2089 code internals. 2090 2091 On 64-bit, the kernel physical and virtual addresses are 2092 randomized separately. The physical address will be anywhere 2093 between 16MB and the top of physical memory (up to 64TB). The 2094 virtual address will be randomized from 16MB up to 1GB (9 bits 2095 of entropy). Note that this also reduces the memory space 2096 available to kernel modules from 1.5GB to 1GB. 2097 2098 On 32-bit, the kernel physical and virtual addresses are 2099 randomized together. They will be randomized from 16MB up to 2100 512MB (8 bits of entropy). 2101 2102 Entropy is generated using the RDRAND instruction if it is 2103 supported. If RDTSC is supported, its value is mixed into 2104 the entropy pool as well. If neither RDRAND nor RDTSC are 2105 supported, then entropy is read from the i8254 timer. The 2106 usable entropy is limited by the kernel being built using 2107 2GB addressing, and that PHYSICAL_ALIGN must be at a 2108 minimum of 2MB. As a result, only 10 bits of entropy are 2109 theoretically possible, but the implementations are further 2110 limited due to memory layouts. 2111 2112 If unsure, say Y. 2113 2114# Relocation on x86 needs some additional build support 2115config X86_NEED_RELOCS 2116 def_bool y 2117 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2118 2119config PHYSICAL_ALIGN 2120 hex "Alignment value to which kernel should be aligned" 2121 default "0x200000" 2122 range 0x2000 0x1000000 if X86_32 2123 range 0x200000 0x1000000 if X86_64 2124 ---help--- 2125 This value puts the alignment restrictions on physical address 2126 where kernel is loaded and run from. Kernel is compiled for an 2127 address which meets above alignment restriction. 2128 2129 If bootloader loads the kernel at a non-aligned address and 2130 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2131 address aligned to above value and run from there. 2132 2133 If bootloader loads the kernel at a non-aligned address and 2134 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2135 load address and decompress itself to the address it has been 2136 compiled for and run from there. The address for which kernel is 2137 compiled already meets above alignment restrictions. Hence the 2138 end result is that kernel runs from a physical address meeting 2139 above alignment restrictions. 2140 2141 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2142 this value must be a multiple of 0x200000. 2143 2144 Don't change this unless you know what you are doing. 2145 2146config RANDOMIZE_MEMORY 2147 bool "Randomize the kernel memory sections" 2148 depends on X86_64 2149 depends on RANDOMIZE_BASE 2150 default RANDOMIZE_BASE 2151 ---help--- 2152 Randomizes the base virtual address of kernel memory sections 2153 (physical memory mapping, vmalloc & vmemmap). This security feature 2154 makes exploits relying on predictable memory locations less reliable. 2155 2156 The order of allocations remains unchanged. Entropy is generated in 2157 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2158 configuration have in average 30,000 different possible virtual 2159 addresses for each memory section. 2160 2161 If unsure, say Y. 2162 2163config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2164 hex "Physical memory mapping padding" if EXPERT 2165 depends on RANDOMIZE_MEMORY 2166 default "0xa" if MEMORY_HOTPLUG 2167 default "0x0" 2168 range 0x1 0x40 if MEMORY_HOTPLUG 2169 range 0x0 0x40 2170 ---help--- 2171 Define the padding in terabytes added to the existing physical 2172 memory size during kernel memory randomization. It is useful 2173 for memory hotplug support but reduces the entropy available for 2174 address randomization. 2175 2176 If unsure, leave at the default value. 2177 2178config HOTPLUG_CPU 2179 bool "Support for hot-pluggable CPUs" 2180 depends on SMP 2181 ---help--- 2182 Say Y here to allow turning CPUs off and on. CPUs can be 2183 controlled through /sys/devices/system/cpu. 2184 ( Note: power management support will enable this option 2185 automatically on SMP systems. ) 2186 Say N if you want to disable CPU hotplug. 2187 2188config BOOTPARAM_HOTPLUG_CPU0 2189 bool "Set default setting of cpu0_hotpluggable" 2190 default n 2191 depends on HOTPLUG_CPU 2192 ---help--- 2193 Set whether default state of cpu0_hotpluggable is on or off. 2194 2195 Say Y here to enable CPU0 hotplug by default. If this switch 2196 is turned on, there is no need to give cpu0_hotplug kernel 2197 parameter and the CPU0 hotplug feature is enabled by default. 2198 2199 Please note: there are two known CPU0 dependencies if you want 2200 to enable the CPU0 hotplug feature either by this switch or by 2201 cpu0_hotplug kernel parameter. 2202 2203 First, resume from hibernate or suspend always starts from CPU0. 2204 So hibernate and suspend are prevented if CPU0 is offline. 2205 2206 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2207 offline if any interrupt can not migrate out of CPU0. There may 2208 be other CPU0 dependencies. 2209 2210 Please make sure the dependencies are under your control before 2211 you enable this feature. 2212 2213 Say N if you don't want to enable CPU0 hotplug feature by default. 2214 You still can enable the CPU0 hotplug feature at boot by kernel 2215 parameter cpu0_hotplug. 2216 2217config DEBUG_HOTPLUG_CPU0 2218 def_bool n 2219 prompt "Debug CPU0 hotplug" 2220 depends on HOTPLUG_CPU 2221 ---help--- 2222 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2223 soon as possible and boots up userspace with CPU0 offlined. User 2224 can online CPU0 back after boot time. 2225 2226 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2227 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2228 compilation or giving cpu0_hotplug kernel parameter at boot. 2229 2230 If unsure, say N. 2231 2232config COMPAT_VDSO 2233 def_bool n 2234 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2235 depends on COMPAT_32 2236 ---help--- 2237 Certain buggy versions of glibc will crash if they are 2238 presented with a 32-bit vDSO that is not mapped at the address 2239 indicated in its segment table. 2240 2241 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2242 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2243 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2244 the only released version with the bug, but OpenSUSE 9 2245 contains a buggy "glibc 2.3.2". 2246 2247 The symptom of the bug is that everything crashes on startup, saying: 2248 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2249 2250 Saying Y here changes the default value of the vdso32 boot 2251 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2252 This works around the glibc bug but hurts performance. 2253 2254 If unsure, say N: if you are compiling your own kernel, you 2255 are unlikely to be using a buggy version of glibc. 2256 2257choice 2258 prompt "vsyscall table for legacy applications" 2259 depends on X86_64 2260 default LEGACY_VSYSCALL_EMULATE 2261 help 2262 Legacy user code that does not know how to find the vDSO expects 2263 to be able to issue three syscalls by calling fixed addresses in 2264 kernel space. Since this location is not randomized with ASLR, 2265 it can be used to assist security vulnerability exploitation. 2266 2267 This setting can be changed at boot time via the kernel command 2268 line parameter vsyscall=[native|emulate|none]. 2269 2270 On a system with recent enough glibc (2.14 or newer) and no 2271 static binaries, you can say None without a performance penalty 2272 to improve security. 2273 2274 If unsure, select "Emulate". 2275 2276 config LEGACY_VSYSCALL_NATIVE 2277 bool "Native" 2278 help 2279 Actual executable code is located in the fixed vsyscall 2280 address mapping, implementing time() efficiently. Since 2281 this makes the mapping executable, it can be used during 2282 security vulnerability exploitation (traditionally as 2283 ROP gadgets). This configuration is not recommended. 2284 2285 config LEGACY_VSYSCALL_EMULATE 2286 bool "Emulate" 2287 help 2288 The kernel traps and emulates calls into the fixed 2289 vsyscall address mapping. This makes the mapping 2290 non-executable, but it still contains known contents, 2291 which could be used in certain rare security vulnerability 2292 exploits. This configuration is recommended when userspace 2293 still uses the vsyscall area. 2294 2295 config LEGACY_VSYSCALL_NONE 2296 bool "None" 2297 help 2298 There will be no vsyscall mapping at all. This will 2299 eliminate any risk of ASLR bypass due to the vsyscall 2300 fixed address mapping. Attempts to use the vsyscalls 2301 will be reported to dmesg, so that either old or 2302 malicious userspace programs can be identified. 2303 2304endchoice 2305 2306config CMDLINE_BOOL 2307 bool "Built-in kernel command line" 2308 ---help--- 2309 Allow for specifying boot arguments to the kernel at 2310 build time. On some systems (e.g. embedded ones), it is 2311 necessary or convenient to provide some or all of the 2312 kernel boot arguments with the kernel itself (that is, 2313 to not rely on the boot loader to provide them.) 2314 2315 To compile command line arguments into the kernel, 2316 set this option to 'Y', then fill in the 2317 boot arguments in CONFIG_CMDLINE. 2318 2319 Systems with fully functional boot loaders (i.e. non-embedded) 2320 should leave this option set to 'N'. 2321 2322config CMDLINE 2323 string "Built-in kernel command string" 2324 depends on CMDLINE_BOOL 2325 default "" 2326 ---help--- 2327 Enter arguments here that should be compiled into the kernel 2328 image and used at boot time. If the boot loader provides a 2329 command line at boot time, it is appended to this string to 2330 form the full kernel command line, when the system boots. 2331 2332 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2333 change this behavior. 2334 2335 In most cases, the command line (whether built-in or provided 2336 by the boot loader) should specify the device for the root 2337 file system. 2338 2339config CMDLINE_OVERRIDE 2340 bool "Built-in command line overrides boot loader arguments" 2341 depends on CMDLINE_BOOL 2342 ---help--- 2343 Set this option to 'Y' to have the kernel ignore the boot loader 2344 command line, and use ONLY the built-in command line. 2345 2346 This is used to work around broken boot loaders. This should 2347 be set to 'N' under normal conditions. 2348 2349config MODIFY_LDT_SYSCALL 2350 bool "Enable the LDT (local descriptor table)" if EXPERT 2351 default y 2352 ---help--- 2353 Linux can allow user programs to install a per-process x86 2354 Local Descriptor Table (LDT) using the modify_ldt(2) system 2355 call. This is required to run 16-bit or segmented code such as 2356 DOSEMU or some Wine programs. It is also used by some very old 2357 threading libraries. 2358 2359 Enabling this feature adds a small amount of overhead to 2360 context switches and increases the low-level kernel attack 2361 surface. Disabling it removes the modify_ldt(2) system call. 2362 2363 Saying 'N' here may make sense for embedded or server kernels. 2364 2365source "kernel/livepatch/Kconfig" 2366 2367endmenu 2368 2369config ARCH_HAS_ADD_PAGES 2370 def_bool y 2371 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2372 2373config ARCH_ENABLE_MEMORY_HOTPLUG 2374 def_bool y 2375 depends on X86_64 || (X86_32 && HIGHMEM) 2376 2377config ARCH_ENABLE_MEMORY_HOTREMOVE 2378 def_bool y 2379 depends on MEMORY_HOTPLUG 2380 2381config USE_PERCPU_NUMA_NODE_ID 2382 def_bool y 2383 depends on NUMA 2384 2385config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2386 def_bool y 2387 depends on X86_64 || X86_PAE 2388 2389config ARCH_ENABLE_HUGEPAGE_MIGRATION 2390 def_bool y 2391 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2392 2393config ARCH_ENABLE_THP_MIGRATION 2394 def_bool y 2395 depends on X86_64 && TRANSPARENT_HUGEPAGE 2396 2397menu "Power management and ACPI options" 2398 2399config ARCH_HIBERNATION_HEADER 2400 def_bool y 2401 depends on X86_64 && HIBERNATION 2402 2403source "kernel/power/Kconfig" 2404 2405source "drivers/acpi/Kconfig" 2406 2407source "drivers/sfi/Kconfig" 2408 2409config X86_APM_BOOT 2410 def_bool y 2411 depends on APM 2412 2413menuconfig APM 2414 tristate "APM (Advanced Power Management) BIOS support" 2415 depends on X86_32 && PM_SLEEP 2416 ---help--- 2417 APM is a BIOS specification for saving power using several different 2418 techniques. This is mostly useful for battery powered laptops with 2419 APM compliant BIOSes. If you say Y here, the system time will be 2420 reset after a RESUME operation, the /proc/apm device will provide 2421 battery status information, and user-space programs will receive 2422 notification of APM "events" (e.g. battery status change). 2423 2424 If you select "Y" here, you can disable actual use of the APM 2425 BIOS by passing the "apm=off" option to the kernel at boot time. 2426 2427 Note that the APM support is almost completely disabled for 2428 machines with more than one CPU. 2429 2430 In order to use APM, you will need supporting software. For location 2431 and more information, read <file:Documentation/power/apm-acpi.txt> 2432 and the Battery Powered Linux mini-HOWTO, available from 2433 <http://www.tldp.org/docs.html#howto>. 2434 2435 This driver does not spin down disk drives (see the hdparm(8) 2436 manpage ("man 8 hdparm") for that), and it doesn't turn off 2437 VESA-compliant "green" monitors. 2438 2439 This driver does not support the TI 4000M TravelMate and the ACER 2440 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2441 desktop machines also don't have compliant BIOSes, and this driver 2442 may cause those machines to panic during the boot phase. 2443 2444 Generally, if you don't have a battery in your machine, there isn't 2445 much point in using this driver and you should say N. If you get 2446 random kernel OOPSes or reboots that don't seem to be related to 2447 anything, try disabling/enabling this option (or disabling/enabling 2448 APM in your BIOS). 2449 2450 Some other things you should try when experiencing seemingly random, 2451 "weird" problems: 2452 2453 1) make sure that you have enough swap space and that it is 2454 enabled. 2455 2) pass the "no-hlt" option to the kernel 2456 3) switch on floating point emulation in the kernel and pass 2457 the "no387" option to the kernel 2458 4) pass the "floppy=nodma" option to the kernel 2459 5) pass the "mem=4M" option to the kernel (thereby disabling 2460 all but the first 4 MB of RAM) 2461 6) make sure that the CPU is not over clocked. 2462 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2463 8) disable the cache from your BIOS settings 2464 9) install a fan for the video card or exchange video RAM 2465 10) install a better fan for the CPU 2466 11) exchange RAM chips 2467 12) exchange the motherboard. 2468 2469 To compile this driver as a module, choose M here: the 2470 module will be called apm. 2471 2472if APM 2473 2474config APM_IGNORE_USER_SUSPEND 2475 bool "Ignore USER SUSPEND" 2476 ---help--- 2477 This option will ignore USER SUSPEND requests. On machines with a 2478 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2479 series notebooks, it is necessary to say Y because of a BIOS bug. 2480 2481config APM_DO_ENABLE 2482 bool "Enable PM at boot time" 2483 ---help--- 2484 Enable APM features at boot time. From page 36 of the APM BIOS 2485 specification: "When disabled, the APM BIOS does not automatically 2486 power manage devices, enter the Standby State, enter the Suspend 2487 State, or take power saving steps in response to CPU Idle calls." 2488 This driver will make CPU Idle calls when Linux is idle (unless this 2489 feature is turned off -- see "Do CPU IDLE calls", below). This 2490 should always save battery power, but more complicated APM features 2491 will be dependent on your BIOS implementation. You may need to turn 2492 this option off if your computer hangs at boot time when using APM 2493 support, or if it beeps continuously instead of suspending. Turn 2494 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2495 T400CDT. This is off by default since most machines do fine without 2496 this feature. 2497 2498config APM_CPU_IDLE 2499 depends on CPU_IDLE 2500 bool "Make CPU Idle calls when idle" 2501 ---help--- 2502 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2503 On some machines, this can activate improved power savings, such as 2504 a slowed CPU clock rate, when the machine is idle. These idle calls 2505 are made after the idle loop has run for some length of time (e.g., 2506 333 mS). On some machines, this will cause a hang at boot time or 2507 whenever the CPU becomes idle. (On machines with more than one CPU, 2508 this option does nothing.) 2509 2510config APM_DISPLAY_BLANK 2511 bool "Enable console blanking using APM" 2512 ---help--- 2513 Enable console blanking using the APM. Some laptops can use this to 2514 turn off the LCD backlight when the screen blanker of the Linux 2515 virtual console blanks the screen. Note that this is only used by 2516 the virtual console screen blanker, and won't turn off the backlight 2517 when using the X Window system. This also doesn't have anything to 2518 do with your VESA-compliant power-saving monitor. Further, this 2519 option doesn't work for all laptops -- it might not turn off your 2520 backlight at all, or it might print a lot of errors to the console, 2521 especially if you are using gpm. 2522 2523config APM_ALLOW_INTS 2524 bool "Allow interrupts during APM BIOS calls" 2525 ---help--- 2526 Normally we disable external interrupts while we are making calls to 2527 the APM BIOS as a measure to lessen the effects of a badly behaving 2528 BIOS implementation. The BIOS should reenable interrupts if it 2529 needs to. Unfortunately, some BIOSes do not -- especially those in 2530 many of the newer IBM Thinkpads. If you experience hangs when you 2531 suspend, try setting this to Y. Otherwise, say N. 2532 2533endif # APM 2534 2535source "drivers/cpufreq/Kconfig" 2536 2537source "drivers/cpuidle/Kconfig" 2538 2539source "drivers/idle/Kconfig" 2540 2541endmenu 2542 2543 2544menu "Bus options (PCI etc.)" 2545 2546config PCI 2547 bool "PCI support" 2548 default y 2549 ---help--- 2550 Find out whether you have a PCI motherboard. PCI is the name of a 2551 bus system, i.e. the way the CPU talks to the other stuff inside 2552 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 2553 VESA. If you have PCI, say Y, otherwise N. 2554 2555choice 2556 prompt "PCI access mode" 2557 depends on X86_32 && PCI 2558 default PCI_GOANY 2559 ---help--- 2560 On PCI systems, the BIOS can be used to detect the PCI devices and 2561 determine their configuration. However, some old PCI motherboards 2562 have BIOS bugs and may crash if this is done. Also, some embedded 2563 PCI-based systems don't have any BIOS at all. Linux can also try to 2564 detect the PCI hardware directly without using the BIOS. 2565 2566 With this option, you can specify how Linux should detect the 2567 PCI devices. If you choose "BIOS", the BIOS will be used, 2568 if you choose "Direct", the BIOS won't be used, and if you 2569 choose "MMConfig", then PCI Express MMCONFIG will be used. 2570 If you choose "Any", the kernel will try MMCONFIG, then the 2571 direct access method and falls back to the BIOS if that doesn't 2572 work. If unsure, go with the default, which is "Any". 2573 2574config PCI_GOBIOS 2575 bool "BIOS" 2576 2577config PCI_GOMMCONFIG 2578 bool "MMConfig" 2579 2580config PCI_GODIRECT 2581 bool "Direct" 2582 2583config PCI_GOOLPC 2584 bool "OLPC XO-1" 2585 depends on OLPC 2586 2587config PCI_GOANY 2588 bool "Any" 2589 2590endchoice 2591 2592config PCI_BIOS 2593 def_bool y 2594 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2595 2596# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2597config PCI_DIRECT 2598 def_bool y 2599 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2600 2601config PCI_MMCONFIG 2602 def_bool y 2603 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY) 2604 2605config PCI_OLPC 2606 def_bool y 2607 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2608 2609config PCI_XEN 2610 def_bool y 2611 depends on PCI && XEN 2612 select SWIOTLB_XEN 2613 2614config PCI_DOMAINS 2615 def_bool y 2616 depends on PCI 2617 2618config PCI_MMCONFIG 2619 bool "Support mmconfig PCI config space access" 2620 depends on X86_64 && PCI && ACPI 2621 2622config PCI_CNB20LE_QUIRK 2623 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2624 depends on PCI 2625 help 2626 Read the PCI windows out of the CNB20LE host bridge. This allows 2627 PCI hotplug to work on systems with the CNB20LE chipset which do 2628 not have ACPI. 2629 2630 There's no public spec for this chipset, and this functionality 2631 is known to be incomplete. 2632 2633 You should say N unless you know you need this. 2634 2635source "drivers/pci/Kconfig" 2636 2637config ISA_BUS 2638 bool "ISA-style bus support on modern systems" if EXPERT 2639 select ISA_BUS_API 2640 help 2641 Enables ISA-style drivers on modern systems. This is necessary to 2642 support PC/104 devices on X86_64 platforms. 2643 2644 If unsure, say N. 2645 2646# x86_64 have no ISA slots, but can have ISA-style DMA. 2647config ISA_DMA_API 2648 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2649 default y 2650 help 2651 Enables ISA-style DMA support for devices requiring such controllers. 2652 If unsure, say Y. 2653 2654if X86_32 2655 2656config ISA 2657 bool "ISA support" 2658 ---help--- 2659 Find out whether you have ISA slots on your motherboard. ISA is the 2660 name of a bus system, i.e. the way the CPU talks to the other stuff 2661 inside your box. Other bus systems are PCI, EISA, MicroChannel 2662 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2663 newer boards don't support it. If you have ISA, say Y, otherwise N. 2664 2665config EISA 2666 bool "EISA support" 2667 depends on ISA 2668 ---help--- 2669 The Extended Industry Standard Architecture (EISA) bus was 2670 developed as an open alternative to the IBM MicroChannel bus. 2671 2672 The EISA bus provided some of the features of the IBM MicroChannel 2673 bus while maintaining backward compatibility with cards made for 2674 the older ISA bus. The EISA bus saw limited use between 1988 and 2675 1995 when it was made obsolete by the PCI bus. 2676 2677 Say Y here if you are building a kernel for an EISA-based machine. 2678 2679 Otherwise, say N. 2680 2681source "drivers/eisa/Kconfig" 2682 2683config SCx200 2684 tristate "NatSemi SCx200 support" 2685 ---help--- 2686 This provides basic support for National Semiconductor's 2687 (now AMD's) Geode processors. The driver probes for the 2688 PCI-IDs of several on-chip devices, so its a good dependency 2689 for other scx200_* drivers. 2690 2691 If compiled as a module, the driver is named scx200. 2692 2693config SCx200HR_TIMER 2694 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2695 depends on SCx200 2696 default y 2697 ---help--- 2698 This driver provides a clocksource built upon the on-chip 2699 27MHz high-resolution timer. Its also a workaround for 2700 NSC Geode SC-1100's buggy TSC, which loses time when the 2701 processor goes idle (as is done by the scheduler). The 2702 other workaround is idle=poll boot option. 2703 2704config OLPC 2705 bool "One Laptop Per Child support" 2706 depends on !X86_PAE 2707 select GPIOLIB 2708 select OF 2709 select OF_PROMTREE 2710 select IRQ_DOMAIN 2711 ---help--- 2712 Add support for detecting the unique features of the OLPC 2713 XO hardware. 2714 2715config OLPC_XO1_PM 2716 bool "OLPC XO-1 Power Management" 2717 depends on OLPC && MFD_CS5535 && PM_SLEEP 2718 select MFD_CORE 2719 ---help--- 2720 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2721 2722config OLPC_XO1_RTC 2723 bool "OLPC XO-1 Real Time Clock" 2724 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2725 ---help--- 2726 Add support for the XO-1 real time clock, which can be used as a 2727 programmable wakeup source. 2728 2729config OLPC_XO1_SCI 2730 bool "OLPC XO-1 SCI extras" 2731 depends on OLPC && OLPC_XO1_PM 2732 depends on INPUT=y 2733 select POWER_SUPPLY 2734 select GPIO_CS5535 2735 select MFD_CORE 2736 ---help--- 2737 Add support for SCI-based features of the OLPC XO-1 laptop: 2738 - EC-driven system wakeups 2739 - Power button 2740 - Ebook switch 2741 - Lid switch 2742 - AC adapter status updates 2743 - Battery status updates 2744 2745config OLPC_XO15_SCI 2746 bool "OLPC XO-1.5 SCI extras" 2747 depends on OLPC && ACPI 2748 select POWER_SUPPLY 2749 ---help--- 2750 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2751 - EC-driven system wakeups 2752 - AC adapter status updates 2753 - Battery status updates 2754 2755config ALIX 2756 bool "PCEngines ALIX System Support (LED setup)" 2757 select GPIOLIB 2758 ---help--- 2759 This option enables system support for the PCEngines ALIX. 2760 At present this just sets up LEDs for GPIO control on 2761 ALIX2/3/6 boards. However, other system specific setup should 2762 get added here. 2763 2764 Note: You must still enable the drivers for GPIO and LED support 2765 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2766 2767 Note: You have to set alix.force=1 for boards with Award BIOS. 2768 2769config NET5501 2770 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2771 select GPIOLIB 2772 ---help--- 2773 This option enables system support for the Soekris Engineering net5501. 2774 2775config GEOS 2776 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2777 select GPIOLIB 2778 depends on DMI 2779 ---help--- 2780 This option enables system support for the Traverse Technologies GEOS. 2781 2782config TS5500 2783 bool "Technologic Systems TS-5500 platform support" 2784 depends on MELAN 2785 select CHECK_SIGNATURE 2786 select NEW_LEDS 2787 select LEDS_CLASS 2788 ---help--- 2789 This option enables system support for the Technologic Systems TS-5500. 2790 2791endif # X86_32 2792 2793config AMD_NB 2794 def_bool y 2795 depends on CPU_SUP_AMD && PCI 2796 2797source "drivers/pcmcia/Kconfig" 2798 2799config RAPIDIO 2800 tristate "RapidIO support" 2801 depends on PCI 2802 default n 2803 help 2804 If enabled this option will include drivers and the core 2805 infrastructure code to support RapidIO interconnect devices. 2806 2807source "drivers/rapidio/Kconfig" 2808 2809config X86_SYSFB 2810 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2811 help 2812 Firmwares often provide initial graphics framebuffers so the BIOS, 2813 bootloader or kernel can show basic video-output during boot for 2814 user-guidance and debugging. Historically, x86 used the VESA BIOS 2815 Extensions and EFI-framebuffers for this, which are mostly limited 2816 to x86. 2817 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2818 framebuffers so the new generic system-framebuffer drivers can be 2819 used on x86. If the framebuffer is not compatible with the generic 2820 modes, it is adverticed as fallback platform framebuffer so legacy 2821 drivers like efifb, vesafb and uvesafb can pick it up. 2822 If this option is not selected, all system framebuffers are always 2823 marked as fallback platform framebuffers as usual. 2824 2825 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2826 not be able to pick up generic system framebuffers if this option 2827 is selected. You are highly encouraged to enable simplefb as 2828 replacement if you select this option. simplefb can correctly deal 2829 with generic system framebuffers. But you should still keep vesafb 2830 and others enabled as fallback if a system framebuffer is 2831 incompatible with simplefb. 2832 2833 If unsure, say Y. 2834 2835endmenu 2836 2837 2838menu "Executable file formats / Emulations" 2839 2840source "fs/Kconfig.binfmt" 2841 2842config IA32_EMULATION 2843 bool "IA32 Emulation" 2844 depends on X86_64 2845 select ARCH_WANT_OLD_COMPAT_IPC 2846 select BINFMT_ELF 2847 select COMPAT_BINFMT_ELF 2848 select COMPAT_OLD_SIGACTION 2849 ---help--- 2850 Include code to run legacy 32-bit programs under a 2851 64-bit kernel. You should likely turn this on, unless you're 2852 100% sure that you don't have any 32-bit programs left. 2853 2854config IA32_AOUT 2855 tristate "IA32 a.out support" 2856 depends on IA32_EMULATION 2857 ---help--- 2858 Support old a.out binaries in the 32bit emulation. 2859 2860config X86_X32 2861 bool "x32 ABI for 64-bit mode" 2862 depends on X86_64 2863 ---help--- 2864 Include code to run binaries for the x32 native 32-bit ABI 2865 for 64-bit processors. An x32 process gets access to the 2866 full 64-bit register file and wide data path while leaving 2867 pointers at 32 bits for smaller memory footprint. 2868 2869 You will need a recent binutils (2.22 or later) with 2870 elf32_x86_64 support enabled to compile a kernel with this 2871 option set. 2872 2873config COMPAT_32 2874 def_bool y 2875 depends on IA32_EMULATION || X86_32 2876 select HAVE_UID16 2877 select OLD_SIGSUSPEND3 2878 2879config COMPAT 2880 def_bool y 2881 depends on IA32_EMULATION || X86_X32 2882 2883if COMPAT 2884config COMPAT_FOR_U64_ALIGNMENT 2885 def_bool y 2886 2887config SYSVIPC_COMPAT 2888 def_bool y 2889 depends on SYSVIPC 2890endif 2891 2892endmenu 2893 2894 2895config HAVE_ATOMIC_IOMAP 2896 def_bool y 2897 depends on X86_32 2898 2899config X86_DEV_DMA_OPS 2900 bool 2901 depends on X86_64 || STA2X11 2902 2903config X86_DMA_REMAP 2904 bool 2905 depends on STA2X11 2906 2907config HAVE_GENERIC_GUP 2908 def_bool y 2909 2910source "net/Kconfig" 2911 2912source "drivers/Kconfig" 2913 2914source "drivers/firmware/Kconfig" 2915 2916source "fs/Kconfig" 2917 2918source "arch/x86/Kconfig.debug" 2919 2920source "security/Kconfig" 2921 2922source "crypto/Kconfig" 2923 2924source "arch/x86/kvm/Kconfig" 2925 2926source "lib/Kconfig" 2927