1# Select 32 or 64 bit 2config 64BIT 3 bool "64-bit kernel" if ARCH = "x86" 4 default ARCH != "i386" 5 ---help--- 6 Say yes to build a 64-bit kernel - formerly known as x86_64 7 Say no to build a 32-bit kernel - formerly known as i386 8 9config X86_32 10 def_bool y 11 depends on !64BIT 12 select CLKSRC_I8253 13 select HAVE_UID16 14 15config X86_64 16 def_bool y 17 depends on 64BIT 18 select X86_DEV_DMA_OPS 19 select ARCH_USE_CMPXCHG_LOCKREF 20 21### Arch settings 22config X86 23 def_bool y 24 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 25 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS 26 select ARCH_HAS_FAST_MULTIPLIER 27 select ARCH_HAS_GCOV_PROFILE_ALL 28 select ARCH_MIGHT_HAVE_PC_PARPORT 29 select ARCH_MIGHT_HAVE_PC_SERIO 30 select HAVE_AOUT if X86_32 31 select HAVE_UNSTABLE_SCHED_CLOCK 32 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 33 select ARCH_SUPPORTS_INT128 if X86_64 34 select HAVE_IDE 35 select HAVE_OPROFILE 36 select HAVE_PCSPKR_PLATFORM 37 select HAVE_PERF_EVENTS 38 select HAVE_IOREMAP_PROT 39 select HAVE_KPROBES 40 select HAVE_MEMBLOCK 41 select HAVE_MEMBLOCK_NODE_MAP 42 select ARCH_DISCARD_MEMBLOCK 43 select ARCH_WANT_OPTIONAL_GPIOLIB 44 select ARCH_WANT_FRAME_POINTERS 45 select HAVE_DMA_ATTRS 46 select HAVE_DMA_CONTIGUOUS 47 select HAVE_KRETPROBES 48 select GENERIC_EARLY_IOREMAP 49 select HAVE_OPTPROBES 50 select HAVE_KPROBES_ON_FTRACE 51 select HAVE_FTRACE_MCOUNT_RECORD 52 select HAVE_FENTRY if X86_64 53 select HAVE_C_RECORDMCOUNT 54 select HAVE_DYNAMIC_FTRACE 55 select HAVE_DYNAMIC_FTRACE_WITH_REGS 56 select HAVE_FUNCTION_TRACER 57 select HAVE_FUNCTION_GRAPH_TRACER 58 select HAVE_FUNCTION_GRAPH_FP_TEST 59 select HAVE_SYSCALL_TRACEPOINTS 60 select SYSCTL_EXCEPTION_TRACE 61 select HAVE_KVM 62 select HAVE_ARCH_KGDB 63 select HAVE_ARCH_TRACEHOOK 64 select HAVE_GENERIC_DMA_COHERENT if X86_32 65 select HAVE_EFFICIENT_UNALIGNED_ACCESS 66 select USER_STACKTRACE_SUPPORT 67 select HAVE_REGS_AND_STACK_ACCESS_API 68 select HAVE_DMA_API_DEBUG 69 select HAVE_KERNEL_GZIP 70 select HAVE_KERNEL_BZIP2 71 select HAVE_KERNEL_LZMA 72 select HAVE_KERNEL_XZ 73 select HAVE_KERNEL_LZO 74 select HAVE_KERNEL_LZ4 75 select HAVE_HW_BREAKPOINT 76 select HAVE_MIXED_BREAKPOINTS_REGS 77 select PERF_EVENTS 78 select HAVE_PERF_EVENTS_NMI 79 select HAVE_PERF_REGS 80 select HAVE_PERF_USER_STACK_DUMP 81 select HAVE_DEBUG_KMEMLEAK 82 select ANON_INODES 83 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 84 select HAVE_CMPXCHG_LOCAL 85 select HAVE_CMPXCHG_DOUBLE 86 select HAVE_ARCH_KMEMCHECK 87 select HAVE_USER_RETURN_NOTIFIER 88 select ARCH_BINFMT_ELF_RANDOMIZE_PIE 89 select HAVE_ARCH_JUMP_LABEL 90 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE 91 select SPARSE_IRQ 92 select GENERIC_FIND_FIRST_BIT 93 select GENERIC_IRQ_PROBE 94 select GENERIC_PENDING_IRQ if SMP 95 select GENERIC_IRQ_SHOW 96 select GENERIC_CLOCKEVENTS_MIN_ADJUST 97 select IRQ_FORCED_THREADING 98 select HAVE_BPF_JIT if X86_64 99 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 100 select ARCH_HAS_SG_CHAIN 101 select CLKEVT_I8253 102 select ARCH_HAVE_NMI_SAFE_CMPXCHG 103 select GENERIC_IOMAP 104 select DCACHE_WORD_ACCESS 105 select GENERIC_SMP_IDLE_THREAD 106 select ARCH_WANT_IPC_PARSE_VERSION if X86_32 107 select HAVE_ARCH_SECCOMP_FILTER 108 select BUILDTIME_EXTABLE_SORT 109 select GENERIC_CMOS_UPDATE 110 select HAVE_ARCH_SOFT_DIRTY if X86_64 111 select CLOCKSOURCE_WATCHDOG 112 select GENERIC_CLOCKEVENTS 113 select ARCH_CLOCKSOURCE_DATA 114 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 115 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 116 select GENERIC_TIME_VSYSCALL 117 select GENERIC_STRNCPY_FROM_USER 118 select GENERIC_STRNLEN_USER 119 select HAVE_CONTEXT_TRACKING if X86_64 120 select HAVE_IRQ_TIME_ACCOUNTING 121 select VIRT_TO_BUS 122 select MODULES_USE_ELF_REL if X86_32 123 select MODULES_USE_ELF_RELA if X86_64 124 select CLONE_BACKWARDS if X86_32 125 select ARCH_USE_BUILTIN_BSWAP 126 select ARCH_USE_QUEUE_RWLOCK 127 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION 128 select OLD_SIGACTION if X86_32 129 select COMPAT_OLD_SIGACTION if IA32_EMULATION 130 select RTC_LIB 131 select HAVE_DEBUG_STACKOVERFLOW 132 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 133 select HAVE_CC_STACKPROTECTOR 134 select GENERIC_CPU_AUTOPROBE 135 select HAVE_ARCH_AUDITSYSCALL 136 select ARCH_SUPPORTS_ATOMIC_RMW 137 select HAVE_ACPI_APEI if ACPI 138 select HAVE_ACPI_APEI_NMI if ACPI 139 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 140 select X86_FEATURE_NAMES if PROC_FS 141 142config INSTRUCTION_DECODER 143 def_bool y 144 depends on KPROBES || PERF_EVENTS || UPROBES 145 146config PERF_EVENTS_INTEL_UNCORE 147 def_bool y 148 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI 149 150config OUTPUT_FORMAT 151 string 152 default "elf32-i386" if X86_32 153 default "elf64-x86-64" if X86_64 154 155config ARCH_DEFCONFIG 156 string 157 default "arch/x86/configs/i386_defconfig" if X86_32 158 default "arch/x86/configs/x86_64_defconfig" if X86_64 159 160config LOCKDEP_SUPPORT 161 def_bool y 162 163config STACKTRACE_SUPPORT 164 def_bool y 165 166config HAVE_LATENCYTOP_SUPPORT 167 def_bool y 168 169config MMU 170 def_bool y 171 172config SBUS 173 bool 174 175config NEED_DMA_MAP_STATE 176 def_bool y 177 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG 178 179config NEED_SG_DMA_LENGTH 180 def_bool y 181 182config GENERIC_ISA_DMA 183 def_bool y 184 depends on ISA_DMA_API 185 186config GENERIC_BUG 187 def_bool y 188 depends on BUG 189 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 190 191config GENERIC_BUG_RELATIVE_POINTERS 192 bool 193 194config GENERIC_HWEIGHT 195 def_bool y 196 197config ARCH_MAY_HAVE_PC_FDC 198 def_bool y 199 depends on ISA_DMA_API 200 201config RWSEM_XCHGADD_ALGORITHM 202 def_bool y 203 204config GENERIC_CALIBRATE_DELAY 205 def_bool y 206 207config ARCH_HAS_CPU_RELAX 208 def_bool y 209 210config ARCH_HAS_CACHE_LINE_SIZE 211 def_bool y 212 213config HAVE_SETUP_PER_CPU_AREA 214 def_bool y 215 216config NEED_PER_CPU_EMBED_FIRST_CHUNK 217 def_bool y 218 219config NEED_PER_CPU_PAGE_FIRST_CHUNK 220 def_bool y 221 222config ARCH_HIBERNATION_POSSIBLE 223 def_bool y 224 225config ARCH_SUSPEND_POSSIBLE 226 def_bool y 227 228config ARCH_WANT_HUGE_PMD_SHARE 229 def_bool y 230 231config ARCH_WANT_GENERAL_HUGETLB 232 def_bool y 233 234config ZONE_DMA32 235 bool 236 default X86_64 237 238config AUDIT_ARCH 239 bool 240 default X86_64 241 242config ARCH_SUPPORTS_OPTIMIZED_INLINING 243 def_bool y 244 245config ARCH_SUPPORTS_DEBUG_PAGEALLOC 246 def_bool y 247 248config HAVE_INTEL_TXT 249 def_bool y 250 depends on INTEL_IOMMU && ACPI 251 252config X86_32_SMP 253 def_bool y 254 depends on X86_32 && SMP 255 256config X86_64_SMP 257 def_bool y 258 depends on X86_64 && SMP 259 260config X86_HT 261 def_bool y 262 depends on SMP 263 264config X86_32_LAZY_GS 265 def_bool y 266 depends on X86_32 && !CC_STACKPROTECTOR 267 268config ARCH_HWEIGHT_CFLAGS 269 string 270 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32 271 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64 272 273config ARCH_SUPPORTS_UPROBES 274 def_bool y 275 276config FIX_EARLYCON_MEM 277 def_bool y 278 279source "init/Kconfig" 280source "kernel/Kconfig.freezer" 281 282menu "Processor type and features" 283 284config ZONE_DMA 285 bool "DMA memory allocation support" if EXPERT 286 default y 287 help 288 DMA memory allocation support allows devices with less than 32-bit 289 addressing to allocate within the first 16MB of address space. 290 Disable if no such devices will be used. 291 292 If unsure, say Y. 293 294config SMP 295 bool "Symmetric multi-processing support" 296 ---help--- 297 This enables support for systems with more than one CPU. If you have 298 a system with only one CPU, say N. If you have a system with more 299 than one CPU, say Y. 300 301 If you say N here, the kernel will run on uni- and multiprocessor 302 machines, but will use only one CPU of a multiprocessor machine. If 303 you say Y here, the kernel will run on many, but not all, 304 uniprocessor machines. On a uniprocessor machine, the kernel 305 will run faster if you say N here. 306 307 Note that if you say Y here and choose architecture "586" or 308 "Pentium" under "Processor family", the kernel will not work on 486 309 architectures. Similarly, multiprocessor kernels for the "PPro" 310 architecture may not work on all Pentium based boards. 311 312 People using multiprocessor machines who say Y here should also say 313 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 314 Management" code will be disabled if you say Y here. 315 316 See also <file:Documentation/x86/i386/IO-APIC.txt>, 317 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at 318 <http://www.tldp.org/docs.html#howto>. 319 320 If you don't know what to do here, say N. 321 322config X86_FEATURE_NAMES 323 bool "Processor feature human-readable names" if EMBEDDED 324 default y 325 ---help--- 326 This option compiles in a table of x86 feature bits and corresponding 327 names. This is required to support /proc/cpuinfo and a few kernel 328 messages. You can disable this to save space, at the expense of 329 making those few kernel messages show numeric feature bits instead. 330 331 If in doubt, say Y. 332 333config X86_X2APIC 334 bool "Support x2apic" 335 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP 336 ---help--- 337 This enables x2apic support on CPUs that have this feature. 338 339 This allows 32-bit apic IDs (so it can support very large systems), 340 and accesses the local apic via MSRs not via mmio. 341 342 If you don't know what to do here, say N. 343 344config X86_MPPARSE 345 bool "Enable MPS table" if ACPI || SFI 346 default y 347 depends on X86_LOCAL_APIC 348 ---help--- 349 For old smp systems that do not have proper acpi support. Newer systems 350 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 351 352config X86_BIGSMP 353 bool "Support for big SMP systems with more than 8 CPUs" 354 depends on X86_32 && SMP 355 ---help--- 356 This option is needed for the systems that have more than 8 CPUs 357 358config GOLDFISH 359 def_bool y 360 depends on X86_GOLDFISH 361 362if X86_32 363config X86_EXTENDED_PLATFORM 364 bool "Support for extended (non-PC) x86 platforms" 365 default y 366 ---help--- 367 If you disable this option then the kernel will only support 368 standard PC platforms. (which covers the vast majority of 369 systems out there.) 370 371 If you enable this option then you'll be able to select support 372 for the following (non-PC) 32 bit x86 platforms: 373 Goldfish (Android emulator) 374 AMD Elan 375 RDC R-321x SoC 376 SGI 320/540 (Visual Workstation) 377 STA2X11-based (e.g. Northville) 378 Moorestown MID devices 379 380 If you have one of these systems, or if you want to build a 381 generic distribution kernel, say Y here - otherwise say N. 382endif 383 384if X86_64 385config X86_EXTENDED_PLATFORM 386 bool "Support for extended (non-PC) x86 platforms" 387 default y 388 ---help--- 389 If you disable this option then the kernel will only support 390 standard PC platforms. (which covers the vast majority of 391 systems out there.) 392 393 If you enable this option then you'll be able to select support 394 for the following (non-PC) 64 bit x86 platforms: 395 Numascale NumaChip 396 ScaleMP vSMP 397 SGI Ultraviolet 398 399 If you have one of these systems, or if you want to build a 400 generic distribution kernel, say Y here - otherwise say N. 401endif 402# This is an alphabetically sorted list of 64 bit extended platforms 403# Please maintain the alphabetic order if and when there are additions 404config X86_NUMACHIP 405 bool "Numascale NumaChip" 406 depends on X86_64 407 depends on X86_EXTENDED_PLATFORM 408 depends on NUMA 409 depends on SMP 410 depends on X86_X2APIC 411 depends on PCI_MMCONFIG 412 ---help--- 413 Adds support for Numascale NumaChip large-SMP systems. Needed to 414 enable more than ~168 cores. 415 If you don't have one of these, you should say N here. 416 417config X86_VSMP 418 bool "ScaleMP vSMP" 419 select HYPERVISOR_GUEST 420 select PARAVIRT 421 depends on X86_64 && PCI 422 depends on X86_EXTENDED_PLATFORM 423 depends on SMP 424 ---help--- 425 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 426 supposed to run on these EM64T-based machines. Only choose this option 427 if you have one of these machines. 428 429config X86_UV 430 bool "SGI Ultraviolet" 431 depends on X86_64 432 depends on X86_EXTENDED_PLATFORM 433 depends on NUMA 434 depends on X86_X2APIC 435 ---help--- 436 This option is needed in order to support SGI Ultraviolet systems. 437 If you don't have one of these, you should say N here. 438 439# Following is an alphabetically sorted list of 32 bit extended platforms 440# Please maintain the alphabetic order if and when there are additions 441 442config X86_GOLDFISH 443 bool "Goldfish (Virtual Platform)" 444 depends on X86_EXTENDED_PLATFORM 445 ---help--- 446 Enable support for the Goldfish virtual platform used primarily 447 for Android development. Unless you are building for the Android 448 Goldfish emulator say N here. 449 450config X86_INTEL_CE 451 bool "CE4100 TV platform" 452 depends on PCI 453 depends on PCI_GODIRECT 454 depends on X86_IO_APIC 455 depends on X86_32 456 depends on X86_EXTENDED_PLATFORM 457 select X86_REBOOTFIXUPS 458 select OF 459 select OF_EARLY_FLATTREE 460 select IRQ_DOMAIN 461 ---help--- 462 Select for the Intel CE media processor (CE4100) SOC. 463 This option compiles in support for the CE4100 SOC for settop 464 boxes and media devices. 465 466config X86_INTEL_MID 467 bool "Intel MID platform support" 468 depends on X86_32 469 depends on X86_EXTENDED_PLATFORM 470 depends on X86_PLATFORM_DEVICES 471 depends on PCI 472 depends on PCI_GOANY 473 depends on X86_IO_APIC 474 select SFI 475 select I2C 476 select DW_APB_TIMER 477 select APB_TIMER 478 select INTEL_SCU_IPC 479 select MFD_INTEL_MSIC 480 ---help--- 481 Select to build a kernel capable of supporting Intel MID (Mobile 482 Internet Device) platform systems which do not have the PCI legacy 483 interfaces. If you are building for a PC class system say N here. 484 485 Intel MID platforms are based on an Intel processor and chipset which 486 consume less power than most of the x86 derivatives. 487 488config X86_INTEL_LPSS 489 bool "Intel Low Power Subsystem Support" 490 depends on ACPI 491 select COMMON_CLK 492 select PINCTRL 493 ---help--- 494 Select to build support for Intel Low Power Subsystem such as 495 found on Intel Lynxpoint PCH. Selecting this option enables 496 things like clock tree (common clock framework) and pincontrol 497 which are needed by the LPSS peripheral drivers. 498 499config IOSF_MBI 500 tristate "Intel SoC IOSF Sideband support for SoC platforms" 501 depends on PCI 502 ---help--- 503 This option enables sideband register access support for Intel SoC 504 platforms. On these platforms the IOSF sideband is used in lieu of 505 MSR's for some register accesses, mostly but not limited to thermal 506 and power. Drivers may query the availability of this device to 507 determine if they need the sideband in order to work on these 508 platforms. The sideband is available on the following SoC products. 509 This list is not meant to be exclusive. 510 - BayTrail 511 - Braswell 512 - Quark 513 514 You should say Y if you are running a kernel on one of these SoC's. 515 516config IOSF_MBI_DEBUG 517 bool "Enable IOSF sideband access through debugfs" 518 depends on IOSF_MBI && DEBUG_FS 519 ---help--- 520 Select this option to expose the IOSF sideband access registers (MCR, 521 MDR, MCRX) through debugfs to write and read register information from 522 different units on the SoC. This is most useful for obtaining device 523 state information for debug and analysis. As this is a general access 524 mechanism, users of this option would have specific knowledge of the 525 device they want to access. 526 527 If you don't require the option or are in doubt, say N. 528 529config X86_RDC321X 530 bool "RDC R-321x SoC" 531 depends on X86_32 532 depends on X86_EXTENDED_PLATFORM 533 select M486 534 select X86_REBOOTFIXUPS 535 ---help--- 536 This option is needed for RDC R-321x system-on-chip, also known 537 as R-8610-(G). 538 If you don't have one of these chips, you should say N here. 539 540config X86_32_NON_STANDARD 541 bool "Support non-standard 32-bit SMP architectures" 542 depends on X86_32 && SMP 543 depends on X86_EXTENDED_PLATFORM 544 ---help--- 545 This option compiles in the bigsmp and STA2X11 default 546 subarchitectures. It is intended for a generic binary 547 kernel. If you select them all, kernel will probe it one by 548 one and will fallback to default. 549 550# Alphabetically sorted list of Non standard 32 bit platforms 551 552config X86_SUPPORTS_MEMORY_FAILURE 553 def_bool y 554 # MCE code calls memory_failure(): 555 depends on X86_MCE 556 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 557 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 558 depends on X86_64 || !SPARSEMEM 559 select ARCH_SUPPORTS_MEMORY_FAILURE 560 561config STA2X11 562 bool "STA2X11 Companion Chip Support" 563 depends on X86_32_NON_STANDARD && PCI 564 select X86_DEV_DMA_OPS 565 select X86_DMA_REMAP 566 select SWIOTLB 567 select MFD_STA2X11 568 select ARCH_REQUIRE_GPIOLIB 569 default n 570 ---help--- 571 This adds support for boards based on the STA2X11 IO-Hub, 572 a.k.a. "ConneXt". The chip is used in place of the standard 573 PC chipset, so all "standard" peripherals are missing. If this 574 option is selected the kernel will still be able to boot on 575 standard PC machines. 576 577config X86_32_IRIS 578 tristate "Eurobraille/Iris poweroff module" 579 depends on X86_32 580 ---help--- 581 The Iris machines from EuroBraille do not have APM or ACPI support 582 to shut themselves down properly. A special I/O sequence is 583 needed to do so, which is what this module does at 584 kernel shutdown. 585 586 This is only for Iris machines from EuroBraille. 587 588 If unused, say N. 589 590config SCHED_OMIT_FRAME_POINTER 591 def_bool y 592 prompt "Single-depth WCHAN output" 593 depends on X86 594 ---help--- 595 Calculate simpler /proc/<PID>/wchan values. If this option 596 is disabled then wchan values will recurse back to the 597 caller function. This provides more accurate wchan values, 598 at the expense of slightly more scheduling overhead. 599 600 If in doubt, say "Y". 601 602menuconfig HYPERVISOR_GUEST 603 bool "Linux guest support" 604 ---help--- 605 Say Y here to enable options for running Linux under various hyper- 606 visors. This option enables basic hypervisor detection and platform 607 setup. 608 609 If you say N, all options in this submenu will be skipped and 610 disabled, and Linux guest support won't be built in. 611 612if HYPERVISOR_GUEST 613 614config PARAVIRT 615 bool "Enable paravirtualization code" 616 ---help--- 617 This changes the kernel so it can modify itself when it is run 618 under a hypervisor, potentially improving performance significantly 619 over full virtualization. However, when run without a hypervisor 620 the kernel is theoretically slower and slightly larger. 621 622config PARAVIRT_DEBUG 623 bool "paravirt-ops debugging" 624 depends on PARAVIRT && DEBUG_KERNEL 625 ---help--- 626 Enable to debug paravirt_ops internals. Specifically, BUG if 627 a paravirt_op is missing when it is called. 628 629config PARAVIRT_SPINLOCKS 630 bool "Paravirtualization layer for spinlocks" 631 depends on PARAVIRT && SMP 632 select UNINLINE_SPIN_UNLOCK 633 ---help--- 634 Paravirtualized spinlocks allow a pvops backend to replace the 635 spinlock implementation with something virtualization-friendly 636 (for example, block the virtual CPU rather than spinning). 637 638 It has a minimal impact on native kernels and gives a nice performance 639 benefit on paravirtualized KVM / Xen kernels. 640 641 If you are unsure how to answer this question, answer Y. 642 643source "arch/x86/xen/Kconfig" 644 645config KVM_GUEST 646 bool "KVM Guest support (including kvmclock)" 647 depends on PARAVIRT 648 select PARAVIRT_CLOCK 649 default y 650 ---help--- 651 This option enables various optimizations for running under the KVM 652 hypervisor. It includes a paravirtualized clock, so that instead 653 of relying on a PIT (or probably other) emulation by the 654 underlying device model, the host provides the guest with 655 timing infrastructure such as time of day, and system time 656 657config KVM_DEBUG_FS 658 bool "Enable debug information for KVM Guests in debugfs" 659 depends on KVM_GUEST && DEBUG_FS 660 default n 661 ---help--- 662 This option enables collection of various statistics for KVM guest. 663 Statistics are displayed in debugfs filesystem. Enabling this option 664 may incur significant overhead. 665 666source "arch/x86/lguest/Kconfig" 667 668config PARAVIRT_TIME_ACCOUNTING 669 bool "Paravirtual steal time accounting" 670 depends on PARAVIRT 671 default n 672 ---help--- 673 Select this option to enable fine granularity task steal time 674 accounting. Time spent executing other tasks in parallel with 675 the current vCPU is discounted from the vCPU power. To account for 676 that, there can be a small performance impact. 677 678 If in doubt, say N here. 679 680config PARAVIRT_CLOCK 681 bool 682 683endif #HYPERVISOR_GUEST 684 685config NO_BOOTMEM 686 def_bool y 687 688config MEMTEST 689 bool "Memtest" 690 ---help--- 691 This option adds a kernel parameter 'memtest', which allows memtest 692 to be set. 693 memtest=0, mean disabled; -- default 694 memtest=1, mean do 1 test pattern; 695 ... 696 memtest=4, mean do 4 test patterns. 697 If you are unsure how to answer this question, answer N. 698 699source "arch/x86/Kconfig.cpu" 700 701config HPET_TIMER 702 def_bool X86_64 703 prompt "HPET Timer Support" if X86_32 704 ---help--- 705 Use the IA-PC HPET (High Precision Event Timer) to manage 706 time in preference to the PIT and RTC, if a HPET is 707 present. 708 HPET is the next generation timer replacing legacy 8254s. 709 The HPET provides a stable time base on SMP 710 systems, unlike the TSC, but it is more expensive to access, 711 as it is off-chip. You can find the HPET spec at 712 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>. 713 714 You can safely choose Y here. However, HPET will only be 715 activated if the platform and the BIOS support this feature. 716 Otherwise the 8254 will be used for timing services. 717 718 Choose N to continue using the legacy 8254 timer. 719 720config HPET_EMULATE_RTC 721 def_bool y 722 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 723 724config APB_TIMER 725 def_bool y if X86_INTEL_MID 726 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 727 select DW_APB_TIMER 728 depends on X86_INTEL_MID && SFI 729 help 730 APB timer is the replacement for 8254, HPET on X86 MID platforms. 731 The APBT provides a stable time base on SMP 732 systems, unlike the TSC, but it is more expensive to access, 733 as it is off-chip. APB timers are always running regardless of CPU 734 C states, they are used as per CPU clockevent device when possible. 735 736# Mark as expert because too many people got it wrong. 737# The code disables itself when not needed. 738config DMI 739 default y 740 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 741 bool "Enable DMI scanning" if EXPERT 742 ---help--- 743 Enabled scanning of DMI to identify machine quirks. Say Y 744 here unless you have verified that your setup is not 745 affected by entries in the DMI blacklist. Required by PNP 746 BIOS code. 747 748config GART_IOMMU 749 bool "Old AMD GART IOMMU support" 750 select SWIOTLB 751 depends on X86_64 && PCI && AMD_NB 752 ---help--- 753 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 754 GART based hardware IOMMUs. 755 756 The GART supports full DMA access for devices with 32-bit access 757 limitations, on systems with more than 3 GB. This is usually needed 758 for USB, sound, many IDE/SATA chipsets and some other devices. 759 760 Newer systems typically have a modern AMD IOMMU, supported via 761 the CONFIG_AMD_IOMMU=y config option. 762 763 In normal configurations this driver is only active when needed: 764 there's more than 3 GB of memory and the system contains a 765 32-bit limited device. 766 767 If unsure, say Y. 768 769config CALGARY_IOMMU 770 bool "IBM Calgary IOMMU support" 771 select SWIOTLB 772 depends on X86_64 && PCI 773 ---help--- 774 Support for hardware IOMMUs in IBM's xSeries x366 and x460 775 systems. Needed to run systems with more than 3GB of memory 776 properly with 32-bit PCI devices that do not support DAC 777 (Double Address Cycle). Calgary also supports bus level 778 isolation, where all DMAs pass through the IOMMU. This 779 prevents them from going anywhere except their intended 780 destination. This catches hard-to-find kernel bugs and 781 mis-behaving drivers and devices that do not use the DMA-API 782 properly to set up their DMA buffers. The IOMMU can be 783 turned off at boot time with the iommu=off parameter. 784 Normally the kernel will make the right choice by itself. 785 If unsure, say Y. 786 787config CALGARY_IOMMU_ENABLED_BY_DEFAULT 788 def_bool y 789 prompt "Should Calgary be enabled by default?" 790 depends on CALGARY_IOMMU 791 ---help--- 792 Should Calgary be enabled by default? if you choose 'y', Calgary 793 will be used (if it exists). If you choose 'n', Calgary will not be 794 used even if it exists. If you choose 'n' and would like to use 795 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 796 If unsure, say Y. 797 798# need this always selected by IOMMU for the VIA workaround 799config SWIOTLB 800 def_bool y if X86_64 801 ---help--- 802 Support for software bounce buffers used on x86-64 systems 803 which don't have a hardware IOMMU. Using this PCI devices 804 which can only access 32-bits of memory can be used on systems 805 with more than 3 GB of memory. 806 If unsure, say Y. 807 808config IOMMU_HELPER 809 def_bool y 810 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU 811 812config MAXSMP 813 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 814 depends on X86_64 && SMP && DEBUG_KERNEL 815 select CPUMASK_OFFSTACK 816 ---help--- 817 Enable maximum number of CPUS and NUMA Nodes for this architecture. 818 If unsure, say N. 819 820config NR_CPUS 821 int "Maximum number of CPUs" if SMP && !MAXSMP 822 range 2 8 if SMP && X86_32 && !X86_BIGSMP 823 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK 824 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64 825 default "1" if !SMP 826 default "8192" if MAXSMP 827 default "32" if SMP && X86_BIGSMP 828 default "8" if SMP 829 ---help--- 830 This allows you to specify the maximum number of CPUs which this 831 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 832 supported value is 4096, otherwise the maximum value is 512. The 833 minimum value which makes sense is 2. 834 835 This is purely to save memory - each supported CPU adds 836 approximately eight kilobytes to the kernel image. 837 838config SCHED_SMT 839 bool "SMT (Hyperthreading) scheduler support" 840 depends on X86_HT 841 ---help--- 842 SMT scheduler support improves the CPU scheduler's decision making 843 when dealing with Intel Pentium 4 chips with HyperThreading at a 844 cost of slightly increased overhead in some places. If unsure say 845 N here. 846 847config SCHED_MC 848 def_bool y 849 prompt "Multi-core scheduler support" 850 depends on X86_HT 851 ---help--- 852 Multi-core scheduler support improves the CPU scheduler's decision 853 making when dealing with multi-core CPU chips at a cost of slightly 854 increased overhead in some places. If unsure say N here. 855 856source "kernel/Kconfig.preempt" 857 858config X86_UP_APIC 859 bool "Local APIC support on uniprocessors" 860 depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI 861 ---help--- 862 A local APIC (Advanced Programmable Interrupt Controller) is an 863 integrated interrupt controller in the CPU. If you have a single-CPU 864 system which has a processor with a local APIC, you can say Y here to 865 enable and use it. If you say Y here even though your machine doesn't 866 have a local APIC, then the kernel will still run with no slowdown at 867 all. The local APIC supports CPU-generated self-interrupts (timer, 868 performance counters), and the NMI watchdog which detects hard 869 lockups. 870 871config X86_UP_IOAPIC 872 bool "IO-APIC support on uniprocessors" 873 depends on X86_UP_APIC 874 ---help--- 875 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 876 SMP-capable replacement for PC-style interrupt controllers. Most 877 SMP systems and many recent uniprocessor systems have one. 878 879 If you have a single-CPU system with an IO-APIC, you can say Y here 880 to use it. If you say Y here even though your machine doesn't have 881 an IO-APIC, then the kernel will still run with no slowdown at all. 882 883config X86_LOCAL_APIC 884 def_bool y 885 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 886 select GENERIC_IRQ_LEGACY_ALLOC_HWIRQ 887 888config X86_IO_APIC 889 def_bool X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC 890 depends on X86_LOCAL_APIC 891 select IRQ_DOMAIN 892 893config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 894 bool "Reroute for broken boot IRQs" 895 depends on X86_IO_APIC 896 ---help--- 897 This option enables a workaround that fixes a source of 898 spurious interrupts. This is recommended when threaded 899 interrupt handling is used on systems where the generation of 900 superfluous "boot interrupts" cannot be disabled. 901 902 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 903 entry in the chipset's IO-APIC is masked (as, e.g. the RT 904 kernel does during interrupt handling). On chipsets where this 905 boot IRQ generation cannot be disabled, this workaround keeps 906 the original IRQ line masked so that only the equivalent "boot 907 IRQ" is delivered to the CPUs. The workaround also tells the 908 kernel to set up the IRQ handler on the boot IRQ line. In this 909 way only one interrupt is delivered to the kernel. Otherwise 910 the spurious second interrupt may cause the kernel to bring 911 down (vital) interrupt lines. 912 913 Only affects "broken" chipsets. Interrupt sharing may be 914 increased on these systems. 915 916config X86_MCE 917 bool "Machine Check / overheating reporting" 918 default y 919 ---help--- 920 Machine Check support allows the processor to notify the 921 kernel if it detects a problem (e.g. overheating, data corruption). 922 The action the kernel takes depends on the severity of the problem, 923 ranging from warning messages to halting the machine. 924 925config X86_MCE_INTEL 926 def_bool y 927 prompt "Intel MCE features" 928 depends on X86_MCE && X86_LOCAL_APIC 929 ---help--- 930 Additional support for intel specific MCE features such as 931 the thermal monitor. 932 933config X86_MCE_AMD 934 def_bool y 935 prompt "AMD MCE features" 936 depends on X86_MCE && X86_LOCAL_APIC 937 ---help--- 938 Additional support for AMD specific MCE features such as 939 the DRAM Error Threshold. 940 941config X86_ANCIENT_MCE 942 bool "Support for old Pentium 5 / WinChip machine checks" 943 depends on X86_32 && X86_MCE 944 ---help--- 945 Include support for machine check handling on old Pentium 5 or WinChip 946 systems. These typically need to be enabled explicitly on the command 947 line. 948 949config X86_MCE_THRESHOLD 950 depends on X86_MCE_AMD || X86_MCE_INTEL 951 def_bool y 952 953config X86_MCE_INJECT 954 depends on X86_MCE 955 tristate "Machine check injector support" 956 ---help--- 957 Provide support for injecting machine checks for testing purposes. 958 If you don't know what a machine check is and you don't do kernel 959 QA it is safe to say n. 960 961config X86_THERMAL_VECTOR 962 def_bool y 963 depends on X86_MCE_INTEL 964 965config VM86 966 bool "Enable VM86 support" if EXPERT 967 default y 968 depends on X86_32 969 ---help--- 970 This option is required by programs like DOSEMU to run 971 16-bit real mode legacy code on x86 processors. It also may 972 be needed by software like XFree86 to initialize some video 973 cards via BIOS. Disabling this option saves about 6K. 974 975config X86_16BIT 976 bool "Enable support for 16-bit segments" if EXPERT 977 default y 978 ---help--- 979 This option is required by programs like Wine to run 16-bit 980 protected mode legacy code on x86 processors. Disabling 981 this option saves about 300 bytes on i386, or around 6K text 982 plus 16K runtime memory on x86-64, 983 984config X86_ESPFIX32 985 def_bool y 986 depends on X86_16BIT && X86_32 987 988config X86_ESPFIX64 989 def_bool y 990 depends on X86_16BIT && X86_64 991 992config X86_VSYSCALL_EMULATION 993 bool "Enable vsyscall emulation" if EXPERT 994 default y 995 depends on X86_64 996 ---help--- 997 This enables emulation of the legacy vsyscall page. Disabling 998 it is roughly equivalent to booting with vsyscall=none, except 999 that it will also disable the helpful warning if a program 1000 tries to use a vsyscall. With this option set to N, offending 1001 programs will just segfault, citing addresses of the form 1002 0xffffffffff600?00. 1003 1004 This option is required by many programs built before 2013, and 1005 care should be used even with newer programs if set to N. 1006 1007 Disabling this option saves about 7K of kernel size and 1008 possibly 4K of additional runtime pagetable memory. 1009 1010config TOSHIBA 1011 tristate "Toshiba Laptop support" 1012 depends on X86_32 1013 ---help--- 1014 This adds a driver to safely access the System Management Mode of 1015 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1016 not work on models with a Phoenix BIOS. The System Management Mode 1017 is used to set the BIOS and power saving options on Toshiba portables. 1018 1019 For information on utilities to make use of this driver see the 1020 Toshiba Linux utilities web site at: 1021 <http://www.buzzard.org.uk/toshiba/>. 1022 1023 Say Y if you intend to run this kernel on a Toshiba portable. 1024 Say N otherwise. 1025 1026config I8K 1027 tristate "Dell laptop support" 1028 select HWMON 1029 ---help--- 1030 This adds a driver to safely access the System Management Mode 1031 of the CPU on the Dell Inspiron 8000. The System Management Mode 1032 is used to read cpu temperature and cooling fan status and to 1033 control the fans on the I8K portables. 1034 1035 This driver has been tested only on the Inspiron 8000 but it may 1036 also work with other Dell laptops. You can force loading on other 1037 models by passing the parameter `force=1' to the module. Use at 1038 your own risk. 1039 1040 For information on utilities to make use of this driver see the 1041 I8K Linux utilities web site at: 1042 <http://people.debian.org/~dz/i8k/> 1043 1044 Say Y if you intend to run this kernel on a Dell Inspiron 8000. 1045 Say N otherwise. 1046 1047config X86_REBOOTFIXUPS 1048 bool "Enable X86 board specific fixups for reboot" 1049 depends on X86_32 1050 ---help--- 1051 This enables chipset and/or board specific fixups to be done 1052 in order to get reboot to work correctly. This is only needed on 1053 some combinations of hardware and BIOS. The symptom, for which 1054 this config is intended, is when reboot ends with a stalled/hung 1055 system. 1056 1057 Currently, the only fixup is for the Geode machines using 1058 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1059 1060 Say Y if you want to enable the fixup. Currently, it's safe to 1061 enable this option even if you don't need it. 1062 Say N otherwise. 1063 1064config MICROCODE 1065 tristate "CPU microcode loading support" 1066 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1067 select FW_LOADER 1068 ---help--- 1069 1070 If you say Y here, you will be able to update the microcode on 1071 certain Intel and AMD processors. The Intel support is for the 1072 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, 1073 Xeon etc. The AMD support is for families 0x10 and later. You will 1074 obviously need the actual microcode binary data itself which is not 1075 shipped with the Linux kernel. 1076 1077 This option selects the general module only, you need to select 1078 at least one vendor specific module as well. 1079 1080 To compile this driver as a module, choose M here: the module 1081 will be called microcode. 1082 1083config MICROCODE_INTEL 1084 bool "Intel microcode loading support" 1085 depends on MICROCODE 1086 default MICROCODE 1087 select FW_LOADER 1088 ---help--- 1089 This options enables microcode patch loading support for Intel 1090 processors. 1091 1092 For the current Intel microcode data package go to 1093 <https://downloadcenter.intel.com> and search for 1094 'Linux Processor Microcode Data File'. 1095 1096config MICROCODE_AMD 1097 bool "AMD microcode loading support" 1098 depends on MICROCODE 1099 select FW_LOADER 1100 ---help--- 1101 If you select this option, microcode patch loading support for AMD 1102 processors will be enabled. 1103 1104config MICROCODE_OLD_INTERFACE 1105 def_bool y 1106 depends on MICROCODE 1107 1108config MICROCODE_INTEL_EARLY 1109 def_bool n 1110 1111config MICROCODE_AMD_EARLY 1112 def_bool n 1113 1114config MICROCODE_EARLY 1115 bool "Early load microcode" 1116 depends on MICROCODE=y && BLK_DEV_INITRD 1117 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL 1118 select MICROCODE_AMD_EARLY if MICROCODE_AMD 1119 default y 1120 help 1121 This option provides functionality to read additional microcode data 1122 at the beginning of initrd image. The data tells kernel to load 1123 microcode to CPU's as early as possible. No functional change if no 1124 microcode data is glued to the initrd, therefore it's safe to say Y. 1125 1126config X86_MSR 1127 tristate "/dev/cpu/*/msr - Model-specific register support" 1128 ---help--- 1129 This device gives privileged processes access to the x86 1130 Model-Specific Registers (MSRs). It is a character device with 1131 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1132 MSR accesses are directed to a specific CPU on multi-processor 1133 systems. 1134 1135config X86_CPUID 1136 tristate "/dev/cpu/*/cpuid - CPU information support" 1137 ---help--- 1138 This device gives processes access to the x86 CPUID instruction to 1139 be executed on a specific processor. It is a character device 1140 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1141 /dev/cpu/31/cpuid. 1142 1143choice 1144 prompt "High Memory Support" 1145 default HIGHMEM4G 1146 depends on X86_32 1147 1148config NOHIGHMEM 1149 bool "off" 1150 ---help--- 1151 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1152 However, the address space of 32-bit x86 processors is only 4 1153 Gigabytes large. That means that, if you have a large amount of 1154 physical memory, not all of it can be "permanently mapped" by the 1155 kernel. The physical memory that's not permanently mapped is called 1156 "high memory". 1157 1158 If you are compiling a kernel which will never run on a machine with 1159 more than 1 Gigabyte total physical RAM, answer "off" here (default 1160 choice and suitable for most users). This will result in a "3GB/1GB" 1161 split: 3GB are mapped so that each process sees a 3GB virtual memory 1162 space and the remaining part of the 4GB virtual memory space is used 1163 by the kernel to permanently map as much physical memory as 1164 possible. 1165 1166 If the machine has between 1 and 4 Gigabytes physical RAM, then 1167 answer "4GB" here. 1168 1169 If more than 4 Gigabytes is used then answer "64GB" here. This 1170 selection turns Intel PAE (Physical Address Extension) mode on. 1171 PAE implements 3-level paging on IA32 processors. PAE is fully 1172 supported by Linux, PAE mode is implemented on all recent Intel 1173 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1174 then the kernel will not boot on CPUs that don't support PAE! 1175 1176 The actual amount of total physical memory will either be 1177 auto detected or can be forced by using a kernel command line option 1178 such as "mem=256M". (Try "man bootparam" or see the documentation of 1179 your boot loader (lilo or loadlin) about how to pass options to the 1180 kernel at boot time.) 1181 1182 If unsure, say "off". 1183 1184config HIGHMEM4G 1185 bool "4GB" 1186 ---help--- 1187 Select this if you have a 32-bit processor and between 1 and 4 1188 gigabytes of physical RAM. 1189 1190config HIGHMEM64G 1191 bool "64GB" 1192 depends on !M486 1193 select X86_PAE 1194 ---help--- 1195 Select this if you have a 32-bit processor and more than 4 1196 gigabytes of physical RAM. 1197 1198endchoice 1199 1200choice 1201 prompt "Memory split" if EXPERT 1202 default VMSPLIT_3G 1203 depends on X86_32 1204 ---help--- 1205 Select the desired split between kernel and user memory. 1206 1207 If the address range available to the kernel is less than the 1208 physical memory installed, the remaining memory will be available 1209 as "high memory". Accessing high memory is a little more costly 1210 than low memory, as it needs to be mapped into the kernel first. 1211 Note that increasing the kernel address space limits the range 1212 available to user programs, making the address space there 1213 tighter. Selecting anything other than the default 3G/1G split 1214 will also likely make your kernel incompatible with binary-only 1215 kernel modules. 1216 1217 If you are not absolutely sure what you are doing, leave this 1218 option alone! 1219 1220 config VMSPLIT_3G 1221 bool "3G/1G user/kernel split" 1222 config VMSPLIT_3G_OPT 1223 depends on !X86_PAE 1224 bool "3G/1G user/kernel split (for full 1G low memory)" 1225 config VMSPLIT_2G 1226 bool "2G/2G user/kernel split" 1227 config VMSPLIT_2G_OPT 1228 depends on !X86_PAE 1229 bool "2G/2G user/kernel split (for full 2G low memory)" 1230 config VMSPLIT_1G 1231 bool "1G/3G user/kernel split" 1232endchoice 1233 1234config PAGE_OFFSET 1235 hex 1236 default 0xB0000000 if VMSPLIT_3G_OPT 1237 default 0x80000000 if VMSPLIT_2G 1238 default 0x78000000 if VMSPLIT_2G_OPT 1239 default 0x40000000 if VMSPLIT_1G 1240 default 0xC0000000 1241 depends on X86_32 1242 1243config HIGHMEM 1244 def_bool y 1245 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1246 1247config X86_PAE 1248 bool "PAE (Physical Address Extension) Support" 1249 depends on X86_32 && !HIGHMEM4G 1250 ---help--- 1251 PAE is required for NX support, and furthermore enables 1252 larger swapspace support for non-overcommit purposes. It 1253 has the cost of more pagetable lookup overhead, and also 1254 consumes more pagetable space per process. 1255 1256config ARCH_PHYS_ADDR_T_64BIT 1257 def_bool y 1258 depends on X86_64 || X86_PAE 1259 1260config ARCH_DMA_ADDR_T_64BIT 1261 def_bool y 1262 depends on X86_64 || HIGHMEM64G 1263 1264config DIRECT_GBPAGES 1265 bool "Enable 1GB pages for kernel pagetables" if EXPERT 1266 default y 1267 depends on X86_64 1268 ---help--- 1269 Allow the kernel linear mapping to use 1GB pages on CPUs that 1270 support it. This can improve the kernel's performance a tiny bit by 1271 reducing TLB pressure. If in doubt, say "Y". 1272 1273# Common NUMA Features 1274config NUMA 1275 bool "Numa Memory Allocation and Scheduler Support" 1276 depends on SMP 1277 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1278 default y if X86_BIGSMP 1279 ---help--- 1280 Enable NUMA (Non Uniform Memory Access) support. 1281 1282 The kernel will try to allocate memory used by a CPU on the 1283 local memory controller of the CPU and add some more 1284 NUMA awareness to the kernel. 1285 1286 For 64-bit this is recommended if the system is Intel Core i7 1287 (or later), AMD Opteron, or EM64T NUMA. 1288 1289 For 32-bit this is only needed if you boot a 32-bit 1290 kernel on a 64-bit NUMA platform. 1291 1292 Otherwise, you should say N. 1293 1294config AMD_NUMA 1295 def_bool y 1296 prompt "Old style AMD Opteron NUMA detection" 1297 depends on X86_64 && NUMA && PCI 1298 ---help--- 1299 Enable AMD NUMA node topology detection. You should say Y here if 1300 you have a multi processor AMD system. This uses an old method to 1301 read the NUMA configuration directly from the builtin Northbridge 1302 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1303 which also takes priority if both are compiled in. 1304 1305config X86_64_ACPI_NUMA 1306 def_bool y 1307 prompt "ACPI NUMA detection" 1308 depends on X86_64 && NUMA && ACPI && PCI 1309 select ACPI_NUMA 1310 ---help--- 1311 Enable ACPI SRAT based node topology detection. 1312 1313# Some NUMA nodes have memory ranges that span 1314# other nodes. Even though a pfn is valid and 1315# between a node's start and end pfns, it may not 1316# reside on that node. See memmap_init_zone() 1317# for details. 1318config NODES_SPAN_OTHER_NODES 1319 def_bool y 1320 depends on X86_64_ACPI_NUMA 1321 1322config NUMA_EMU 1323 bool "NUMA emulation" 1324 depends on NUMA 1325 ---help--- 1326 Enable NUMA emulation. A flat machine will be split 1327 into virtual nodes when booted with "numa=fake=N", where N is the 1328 number of nodes. This is only useful for debugging. 1329 1330config NODES_SHIFT 1331 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1332 range 1 10 1333 default "10" if MAXSMP 1334 default "6" if X86_64 1335 default "3" 1336 depends on NEED_MULTIPLE_NODES 1337 ---help--- 1338 Specify the maximum number of NUMA Nodes available on the target 1339 system. Increases memory reserved to accommodate various tables. 1340 1341config ARCH_HAVE_MEMORY_PRESENT 1342 def_bool y 1343 depends on X86_32 && DISCONTIGMEM 1344 1345config NEED_NODE_MEMMAP_SIZE 1346 def_bool y 1347 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM) 1348 1349config ARCH_FLATMEM_ENABLE 1350 def_bool y 1351 depends on X86_32 && !NUMA 1352 1353config ARCH_DISCONTIGMEM_ENABLE 1354 def_bool y 1355 depends on NUMA && X86_32 1356 1357config ARCH_DISCONTIGMEM_DEFAULT 1358 def_bool y 1359 depends on NUMA && X86_32 1360 1361config ARCH_SPARSEMEM_ENABLE 1362 def_bool y 1363 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1364 select SPARSEMEM_STATIC if X86_32 1365 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1366 1367config ARCH_SPARSEMEM_DEFAULT 1368 def_bool y 1369 depends on X86_64 1370 1371config ARCH_SELECT_MEMORY_MODEL 1372 def_bool y 1373 depends on ARCH_SPARSEMEM_ENABLE 1374 1375config ARCH_MEMORY_PROBE 1376 bool "Enable sysfs memory/probe interface" 1377 depends on X86_64 && MEMORY_HOTPLUG 1378 help 1379 This option enables a sysfs memory/probe interface for testing. 1380 See Documentation/memory-hotplug.txt for more information. 1381 If you are unsure how to answer this question, answer N. 1382 1383config ARCH_PROC_KCORE_TEXT 1384 def_bool y 1385 depends on X86_64 && PROC_KCORE 1386 1387config ILLEGAL_POINTER_VALUE 1388 hex 1389 default 0 if X86_32 1390 default 0xdead000000000000 if X86_64 1391 1392source "mm/Kconfig" 1393 1394config HIGHPTE 1395 bool "Allocate 3rd-level pagetables from highmem" 1396 depends on HIGHMEM 1397 ---help--- 1398 The VM uses one page table entry for each page of physical memory. 1399 For systems with a lot of RAM, this can be wasteful of precious 1400 low memory. Setting this option will put user-space page table 1401 entries in high memory. 1402 1403config X86_CHECK_BIOS_CORRUPTION 1404 bool "Check for low memory corruption" 1405 ---help--- 1406 Periodically check for memory corruption in low memory, which 1407 is suspected to be caused by BIOS. Even when enabled in the 1408 configuration, it is disabled at runtime. Enable it by 1409 setting "memory_corruption_check=1" on the kernel command 1410 line. By default it scans the low 64k of memory every 60 1411 seconds; see the memory_corruption_check_size and 1412 memory_corruption_check_period parameters in 1413 Documentation/kernel-parameters.txt to adjust this. 1414 1415 When enabled with the default parameters, this option has 1416 almost no overhead, as it reserves a relatively small amount 1417 of memory and scans it infrequently. It both detects corruption 1418 and prevents it from affecting the running system. 1419 1420 It is, however, intended as a diagnostic tool; if repeatable 1421 BIOS-originated corruption always affects the same memory, 1422 you can use memmap= to prevent the kernel from using that 1423 memory. 1424 1425config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1426 bool "Set the default setting of memory_corruption_check" 1427 depends on X86_CHECK_BIOS_CORRUPTION 1428 default y 1429 ---help--- 1430 Set whether the default state of memory_corruption_check is 1431 on or off. 1432 1433config X86_RESERVE_LOW 1434 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1435 default 64 1436 range 4 640 1437 ---help--- 1438 Specify the amount of low memory to reserve for the BIOS. 1439 1440 The first page contains BIOS data structures that the kernel 1441 must not use, so that page must always be reserved. 1442 1443 By default we reserve the first 64K of physical RAM, as a 1444 number of BIOSes are known to corrupt that memory range 1445 during events such as suspend/resume or monitor cable 1446 insertion, so it must not be used by the kernel. 1447 1448 You can set this to 4 if you are absolutely sure that you 1449 trust the BIOS to get all its memory reservations and usages 1450 right. If you know your BIOS have problems beyond the 1451 default 64K area, you can set this to 640 to avoid using the 1452 entire low memory range. 1453 1454 If you have doubts about the BIOS (e.g. suspend/resume does 1455 not work or there's kernel crashes after certain hardware 1456 hotplug events) then you might want to enable 1457 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1458 typical corruption patterns. 1459 1460 Leave this to the default value of 64 if you are unsure. 1461 1462config MATH_EMULATION 1463 bool 1464 prompt "Math emulation" if X86_32 1465 ---help--- 1466 Linux can emulate a math coprocessor (used for floating point 1467 operations) if you don't have one. 486DX and Pentium processors have 1468 a math coprocessor built in, 486SX and 386 do not, unless you added 1469 a 487DX or 387, respectively. (The messages during boot time can 1470 give you some hints here ["man dmesg"].) Everyone needs either a 1471 coprocessor or this emulation. 1472 1473 If you don't have a math coprocessor, you need to say Y here; if you 1474 say Y here even though you have a coprocessor, the coprocessor will 1475 be used nevertheless. (This behavior can be changed with the kernel 1476 command line option "no387", which comes handy if your coprocessor 1477 is broken. Try "man bootparam" or see the documentation of your boot 1478 loader (lilo or loadlin) about how to pass options to the kernel at 1479 boot time.) This means that it is a good idea to say Y here if you 1480 intend to use this kernel on different machines. 1481 1482 More information about the internals of the Linux math coprocessor 1483 emulation can be found in <file:arch/x86/math-emu/README>. 1484 1485 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1486 kernel, it won't hurt. 1487 1488config MTRR 1489 def_bool y 1490 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1491 ---help--- 1492 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1493 the Memory Type Range Registers (MTRRs) may be used to control 1494 processor access to memory ranges. This is most useful if you have 1495 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1496 allows bus write transfers to be combined into a larger transfer 1497 before bursting over the PCI/AGP bus. This can increase performance 1498 of image write operations 2.5 times or more. Saying Y here creates a 1499 /proc/mtrr file which may be used to manipulate your processor's 1500 MTRRs. Typically the X server should use this. 1501 1502 This code has a reasonably generic interface so that similar 1503 control registers on other processors can be easily supported 1504 as well: 1505 1506 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1507 Registers (ARRs) which provide a similar functionality to MTRRs. For 1508 these, the ARRs are used to emulate the MTRRs. 1509 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1510 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1511 write-combining. All of these processors are supported by this code 1512 and it makes sense to say Y here if you have one of them. 1513 1514 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1515 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1516 can lead to all sorts of problems, so it's good to say Y here. 1517 1518 You can safely say Y even if your machine doesn't have MTRRs, you'll 1519 just add about 9 KB to your kernel. 1520 1521 See <file:Documentation/x86/mtrr.txt> for more information. 1522 1523config MTRR_SANITIZER 1524 def_bool y 1525 prompt "MTRR cleanup support" 1526 depends on MTRR 1527 ---help--- 1528 Convert MTRR layout from continuous to discrete, so X drivers can 1529 add writeback entries. 1530 1531 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1532 The largest mtrr entry size for a continuous block can be set with 1533 mtrr_chunk_size. 1534 1535 If unsure, say Y. 1536 1537config MTRR_SANITIZER_ENABLE_DEFAULT 1538 int "MTRR cleanup enable value (0-1)" 1539 range 0 1 1540 default "0" 1541 depends on MTRR_SANITIZER 1542 ---help--- 1543 Enable mtrr cleanup default value 1544 1545config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1546 int "MTRR cleanup spare reg num (0-7)" 1547 range 0 7 1548 default "1" 1549 depends on MTRR_SANITIZER 1550 ---help--- 1551 mtrr cleanup spare entries default, it can be changed via 1552 mtrr_spare_reg_nr=N on the kernel command line. 1553 1554config X86_PAT 1555 def_bool y 1556 prompt "x86 PAT support" if EXPERT 1557 depends on MTRR 1558 ---help--- 1559 Use PAT attributes to setup page level cache control. 1560 1561 PATs are the modern equivalents of MTRRs and are much more 1562 flexible than MTRRs. 1563 1564 Say N here if you see bootup problems (boot crash, boot hang, 1565 spontaneous reboots) or a non-working video driver. 1566 1567 If unsure, say Y. 1568 1569config ARCH_USES_PG_UNCACHED 1570 def_bool y 1571 depends on X86_PAT 1572 1573config ARCH_RANDOM 1574 def_bool y 1575 prompt "x86 architectural random number generator" if EXPERT 1576 ---help--- 1577 Enable the x86 architectural RDRAND instruction 1578 (Intel Bull Mountain technology) to generate random numbers. 1579 If supported, this is a high bandwidth, cryptographically 1580 secure hardware random number generator. 1581 1582config X86_SMAP 1583 def_bool y 1584 prompt "Supervisor Mode Access Prevention" if EXPERT 1585 ---help--- 1586 Supervisor Mode Access Prevention (SMAP) is a security 1587 feature in newer Intel processors. There is a small 1588 performance cost if this enabled and turned on; there is 1589 also a small increase in the kernel size if this is enabled. 1590 1591 If unsure, say Y. 1592 1593config X86_INTEL_MPX 1594 prompt "Intel MPX (Memory Protection Extensions)" 1595 def_bool n 1596 depends on CPU_SUP_INTEL 1597 ---help--- 1598 MPX provides hardware features that can be used in 1599 conjunction with compiler-instrumented code to check 1600 memory references. It is designed to detect buffer 1601 overflow or underflow bugs. 1602 1603 This option enables running applications which are 1604 instrumented or otherwise use MPX. It does not use MPX 1605 itself inside the kernel or to protect the kernel 1606 against bad memory references. 1607 1608 Enabling this option will make the kernel larger: 1609 ~8k of kernel text and 36 bytes of data on a 64-bit 1610 defconfig. It adds a long to the 'mm_struct' which 1611 will increase the kernel memory overhead of each 1612 process and adds some branches to paths used during 1613 exec() and munmap(). 1614 1615 For details, see Documentation/x86/intel_mpx.txt 1616 1617 If unsure, say N. 1618 1619config EFI 1620 bool "EFI runtime service support" 1621 depends on ACPI 1622 select UCS2_STRING 1623 select EFI_RUNTIME_WRAPPERS 1624 ---help--- 1625 This enables the kernel to use EFI runtime services that are 1626 available (such as the EFI variable services). 1627 1628 This option is only useful on systems that have EFI firmware. 1629 In addition, you should use the latest ELILO loader available 1630 at <http://elilo.sourceforge.net> in order to take advantage 1631 of EFI runtime services. However, even with this option, the 1632 resultant kernel should continue to boot on existing non-EFI 1633 platforms. 1634 1635config EFI_STUB 1636 bool "EFI stub support" 1637 depends on EFI && !X86_USE_3DNOW 1638 select RELOCATABLE 1639 ---help--- 1640 This kernel feature allows a bzImage to be loaded directly 1641 by EFI firmware without the use of a bootloader. 1642 1643 See Documentation/efi-stub.txt for more information. 1644 1645config EFI_MIXED 1646 bool "EFI mixed-mode support" 1647 depends on EFI_STUB && X86_64 1648 ---help--- 1649 Enabling this feature allows a 64-bit kernel to be booted 1650 on a 32-bit firmware, provided that your CPU supports 64-bit 1651 mode. 1652 1653 Note that it is not possible to boot a mixed-mode enabled 1654 kernel via the EFI boot stub - a bootloader that supports 1655 the EFI handover protocol must be used. 1656 1657 If unsure, say N. 1658 1659config SECCOMP 1660 def_bool y 1661 prompt "Enable seccomp to safely compute untrusted bytecode" 1662 ---help--- 1663 This kernel feature is useful for number crunching applications 1664 that may need to compute untrusted bytecode during their 1665 execution. By using pipes or other transports made available to 1666 the process as file descriptors supporting the read/write 1667 syscalls, it's possible to isolate those applications in 1668 their own address space using seccomp. Once seccomp is 1669 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1670 and the task is only allowed to execute a few safe syscalls 1671 defined by each seccomp mode. 1672 1673 If unsure, say Y. Only embedded should say N here. 1674 1675source kernel/Kconfig.hz 1676 1677config KEXEC 1678 bool "kexec system call" 1679 ---help--- 1680 kexec is a system call that implements the ability to shutdown your 1681 current kernel, and to start another kernel. It is like a reboot 1682 but it is independent of the system firmware. And like a reboot 1683 you can start any kernel with it, not just Linux. 1684 1685 The name comes from the similarity to the exec system call. 1686 1687 It is an ongoing process to be certain the hardware in a machine 1688 is properly shutdown, so do not be surprised if this code does not 1689 initially work for you. As of this writing the exact hardware 1690 interface is strongly in flux, so no good recommendation can be 1691 made. 1692 1693config KEXEC_FILE 1694 bool "kexec file based system call" 1695 select BUILD_BIN2C 1696 depends on KEXEC 1697 depends on X86_64 1698 depends on CRYPTO=y 1699 depends on CRYPTO_SHA256=y 1700 ---help--- 1701 This is new version of kexec system call. This system call is 1702 file based and takes file descriptors as system call argument 1703 for kernel and initramfs as opposed to list of segments as 1704 accepted by previous system call. 1705 1706config KEXEC_VERIFY_SIG 1707 bool "Verify kernel signature during kexec_file_load() syscall" 1708 depends on KEXEC_FILE 1709 ---help--- 1710 This option makes kernel signature verification mandatory for 1711 kexec_file_load() syscall. If kernel is signature can not be 1712 verified, kexec_file_load() will fail. 1713 1714 This option enforces signature verification at generic level. 1715 One needs to enable signature verification for type of kernel 1716 image being loaded to make sure it works. For example, enable 1717 bzImage signature verification option to be able to load and 1718 verify signatures of bzImage. Otherwise kernel loading will fail. 1719 1720config KEXEC_BZIMAGE_VERIFY_SIG 1721 bool "Enable bzImage signature verification support" 1722 depends on KEXEC_VERIFY_SIG 1723 depends on SIGNED_PE_FILE_VERIFICATION 1724 select SYSTEM_TRUSTED_KEYRING 1725 ---help--- 1726 Enable bzImage signature verification support. 1727 1728config CRASH_DUMP 1729 bool "kernel crash dumps" 1730 depends on X86_64 || (X86_32 && HIGHMEM) 1731 ---help--- 1732 Generate crash dump after being started by kexec. 1733 This should be normally only set in special crash dump kernels 1734 which are loaded in the main kernel with kexec-tools into 1735 a specially reserved region and then later executed after 1736 a crash by kdump/kexec. The crash dump kernel must be compiled 1737 to a memory address not used by the main kernel or BIOS using 1738 PHYSICAL_START, or it must be built as a relocatable image 1739 (CONFIG_RELOCATABLE=y). 1740 For more details see Documentation/kdump/kdump.txt 1741 1742config KEXEC_JUMP 1743 bool "kexec jump" 1744 depends on KEXEC && HIBERNATION 1745 ---help--- 1746 Jump between original kernel and kexeced kernel and invoke 1747 code in physical address mode via KEXEC 1748 1749config PHYSICAL_START 1750 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 1751 default "0x1000000" 1752 ---help--- 1753 This gives the physical address where the kernel is loaded. 1754 1755 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 1756 bzImage will decompress itself to above physical address and 1757 run from there. Otherwise, bzImage will run from the address where 1758 it has been loaded by the boot loader and will ignore above physical 1759 address. 1760 1761 In normal kdump cases one does not have to set/change this option 1762 as now bzImage can be compiled as a completely relocatable image 1763 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 1764 address. This option is mainly useful for the folks who don't want 1765 to use a bzImage for capturing the crash dump and want to use a 1766 vmlinux instead. vmlinux is not relocatable hence a kernel needs 1767 to be specifically compiled to run from a specific memory area 1768 (normally a reserved region) and this option comes handy. 1769 1770 So if you are using bzImage for capturing the crash dump, 1771 leave the value here unchanged to 0x1000000 and set 1772 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 1773 for capturing the crash dump change this value to start of 1774 the reserved region. In other words, it can be set based on 1775 the "X" value as specified in the "crashkernel=YM@XM" 1776 command line boot parameter passed to the panic-ed 1777 kernel. Please take a look at Documentation/kdump/kdump.txt 1778 for more details about crash dumps. 1779 1780 Usage of bzImage for capturing the crash dump is recommended as 1781 one does not have to build two kernels. Same kernel can be used 1782 as production kernel and capture kernel. Above option should have 1783 gone away after relocatable bzImage support is introduced. But it 1784 is present because there are users out there who continue to use 1785 vmlinux for dump capture. This option should go away down the 1786 line. 1787 1788 Don't change this unless you know what you are doing. 1789 1790config RELOCATABLE 1791 bool "Build a relocatable kernel" 1792 default y 1793 ---help--- 1794 This builds a kernel image that retains relocation information 1795 so it can be loaded someplace besides the default 1MB. 1796 The relocations tend to make the kernel binary about 10% larger, 1797 but are discarded at runtime. 1798 1799 One use is for the kexec on panic case where the recovery kernel 1800 must live at a different physical address than the primary 1801 kernel. 1802 1803 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 1804 it has been loaded at and the compile time physical address 1805 (CONFIG_PHYSICAL_START) is used as the minimum location. 1806 1807config RANDOMIZE_BASE 1808 bool "Randomize the address of the kernel image" 1809 depends on RELOCATABLE 1810 default n 1811 ---help--- 1812 Randomizes the physical and virtual address at which the 1813 kernel image is decompressed, as a security feature that 1814 deters exploit attempts relying on knowledge of the location 1815 of kernel internals. 1816 1817 Entropy is generated using the RDRAND instruction if it is 1818 supported. If RDTSC is supported, it is used as well. If 1819 neither RDRAND nor RDTSC are supported, then randomness is 1820 read from the i8254 timer. 1821 1822 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET, 1823 and aligned according to PHYSICAL_ALIGN. Since the kernel is 1824 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a 1825 minimum of 2MiB, only 10 bits of entropy is theoretically 1826 possible. At best, due to page table layouts, 64-bit can use 1827 9 bits of entropy and 32-bit uses 8 bits. 1828 1829 If unsure, say N. 1830 1831config RANDOMIZE_BASE_MAX_OFFSET 1832 hex "Maximum kASLR offset allowed" if EXPERT 1833 depends on RANDOMIZE_BASE 1834 range 0x0 0x20000000 if X86_32 1835 default "0x20000000" if X86_32 1836 range 0x0 0x40000000 if X86_64 1837 default "0x40000000" if X86_64 1838 ---help--- 1839 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical 1840 memory is used to determine the maximal offset in bytes that will 1841 be applied to the kernel when kernel Address Space Layout 1842 Randomization (kASLR) is active. This must be a multiple of 1843 PHYSICAL_ALIGN. 1844 1845 On 32-bit this is limited to 512MiB by page table layouts. The 1846 default is 512MiB. 1847 1848 On 64-bit this is limited by how the kernel fixmap page table is 1849 positioned, so this cannot be larger than 1GiB currently. Without 1850 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel 1851 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the 1852 modules area will shrink to compensate, up to the current maximum 1853 1GiB to 1GiB split. The default is 1GiB. 1854 1855 If unsure, leave at the default value. 1856 1857# Relocation on x86 needs some additional build support 1858config X86_NEED_RELOCS 1859 def_bool y 1860 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 1861 1862config PHYSICAL_ALIGN 1863 hex "Alignment value to which kernel should be aligned" 1864 default "0x200000" 1865 range 0x2000 0x1000000 if X86_32 1866 range 0x200000 0x1000000 if X86_64 1867 ---help--- 1868 This value puts the alignment restrictions on physical address 1869 where kernel is loaded and run from. Kernel is compiled for an 1870 address which meets above alignment restriction. 1871 1872 If bootloader loads the kernel at a non-aligned address and 1873 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 1874 address aligned to above value and run from there. 1875 1876 If bootloader loads the kernel at a non-aligned address and 1877 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 1878 load address and decompress itself to the address it has been 1879 compiled for and run from there. The address for which kernel is 1880 compiled already meets above alignment restrictions. Hence the 1881 end result is that kernel runs from a physical address meeting 1882 above alignment restrictions. 1883 1884 On 32-bit this value must be a multiple of 0x2000. On 64-bit 1885 this value must be a multiple of 0x200000. 1886 1887 Don't change this unless you know what you are doing. 1888 1889config HOTPLUG_CPU 1890 bool "Support for hot-pluggable CPUs" 1891 depends on SMP 1892 ---help--- 1893 Say Y here to allow turning CPUs off and on. CPUs can be 1894 controlled through /sys/devices/system/cpu. 1895 ( Note: power management support will enable this option 1896 automatically on SMP systems. ) 1897 Say N if you want to disable CPU hotplug. 1898 1899config BOOTPARAM_HOTPLUG_CPU0 1900 bool "Set default setting of cpu0_hotpluggable" 1901 default n 1902 depends on HOTPLUG_CPU 1903 ---help--- 1904 Set whether default state of cpu0_hotpluggable is on or off. 1905 1906 Say Y here to enable CPU0 hotplug by default. If this switch 1907 is turned on, there is no need to give cpu0_hotplug kernel 1908 parameter and the CPU0 hotplug feature is enabled by default. 1909 1910 Please note: there are two known CPU0 dependencies if you want 1911 to enable the CPU0 hotplug feature either by this switch or by 1912 cpu0_hotplug kernel parameter. 1913 1914 First, resume from hibernate or suspend always starts from CPU0. 1915 So hibernate and suspend are prevented if CPU0 is offline. 1916 1917 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 1918 offline if any interrupt can not migrate out of CPU0. There may 1919 be other CPU0 dependencies. 1920 1921 Please make sure the dependencies are under your control before 1922 you enable this feature. 1923 1924 Say N if you don't want to enable CPU0 hotplug feature by default. 1925 You still can enable the CPU0 hotplug feature at boot by kernel 1926 parameter cpu0_hotplug. 1927 1928config DEBUG_HOTPLUG_CPU0 1929 def_bool n 1930 prompt "Debug CPU0 hotplug" 1931 depends on HOTPLUG_CPU 1932 ---help--- 1933 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 1934 soon as possible and boots up userspace with CPU0 offlined. User 1935 can online CPU0 back after boot time. 1936 1937 To debug CPU0 hotplug, you need to enable CPU0 offline/online 1938 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 1939 compilation or giving cpu0_hotplug kernel parameter at boot. 1940 1941 If unsure, say N. 1942 1943config COMPAT_VDSO 1944 def_bool n 1945 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 1946 depends on X86_32 || IA32_EMULATION 1947 ---help--- 1948 Certain buggy versions of glibc will crash if they are 1949 presented with a 32-bit vDSO that is not mapped at the address 1950 indicated in its segment table. 1951 1952 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 1953 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 1954 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 1955 the only released version with the bug, but OpenSUSE 9 1956 contains a buggy "glibc 2.3.2". 1957 1958 The symptom of the bug is that everything crashes on startup, saying: 1959 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 1960 1961 Saying Y here changes the default value of the vdso32 boot 1962 option from 1 to 0, which turns off the 32-bit vDSO entirely. 1963 This works around the glibc bug but hurts performance. 1964 1965 If unsure, say N: if you are compiling your own kernel, you 1966 are unlikely to be using a buggy version of glibc. 1967 1968config CMDLINE_BOOL 1969 bool "Built-in kernel command line" 1970 ---help--- 1971 Allow for specifying boot arguments to the kernel at 1972 build time. On some systems (e.g. embedded ones), it is 1973 necessary or convenient to provide some or all of the 1974 kernel boot arguments with the kernel itself (that is, 1975 to not rely on the boot loader to provide them.) 1976 1977 To compile command line arguments into the kernel, 1978 set this option to 'Y', then fill in the 1979 the boot arguments in CONFIG_CMDLINE. 1980 1981 Systems with fully functional boot loaders (i.e. non-embedded) 1982 should leave this option set to 'N'. 1983 1984config CMDLINE 1985 string "Built-in kernel command string" 1986 depends on CMDLINE_BOOL 1987 default "" 1988 ---help--- 1989 Enter arguments here that should be compiled into the kernel 1990 image and used at boot time. If the boot loader provides a 1991 command line at boot time, it is appended to this string to 1992 form the full kernel command line, when the system boots. 1993 1994 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 1995 change this behavior. 1996 1997 In most cases, the command line (whether built-in or provided 1998 by the boot loader) should specify the device for the root 1999 file system. 2000 2001config CMDLINE_OVERRIDE 2002 bool "Built-in command line overrides boot loader arguments" 2003 depends on CMDLINE_BOOL 2004 ---help--- 2005 Set this option to 'Y' to have the kernel ignore the boot loader 2006 command line, and use ONLY the built-in command line. 2007 2008 This is used to work around broken boot loaders. This should 2009 be set to 'N' under normal conditions. 2010 2011endmenu 2012 2013config ARCH_ENABLE_MEMORY_HOTPLUG 2014 def_bool y 2015 depends on X86_64 || (X86_32 && HIGHMEM) 2016 2017config ARCH_ENABLE_MEMORY_HOTREMOVE 2018 def_bool y 2019 depends on MEMORY_HOTPLUG 2020 2021config USE_PERCPU_NUMA_NODE_ID 2022 def_bool y 2023 depends on NUMA 2024 2025config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2026 def_bool y 2027 depends on X86_64 || X86_PAE 2028 2029config ARCH_ENABLE_HUGEPAGE_MIGRATION 2030 def_bool y 2031 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2032 2033menu "Power management and ACPI options" 2034 2035config ARCH_HIBERNATION_HEADER 2036 def_bool y 2037 depends on X86_64 && HIBERNATION 2038 2039source "kernel/power/Kconfig" 2040 2041source "drivers/acpi/Kconfig" 2042 2043source "drivers/sfi/Kconfig" 2044 2045config X86_APM_BOOT 2046 def_bool y 2047 depends on APM 2048 2049menuconfig APM 2050 tristate "APM (Advanced Power Management) BIOS support" 2051 depends on X86_32 && PM_SLEEP 2052 ---help--- 2053 APM is a BIOS specification for saving power using several different 2054 techniques. This is mostly useful for battery powered laptops with 2055 APM compliant BIOSes. If you say Y here, the system time will be 2056 reset after a RESUME operation, the /proc/apm device will provide 2057 battery status information, and user-space programs will receive 2058 notification of APM "events" (e.g. battery status change). 2059 2060 If you select "Y" here, you can disable actual use of the APM 2061 BIOS by passing the "apm=off" option to the kernel at boot time. 2062 2063 Note that the APM support is almost completely disabled for 2064 machines with more than one CPU. 2065 2066 In order to use APM, you will need supporting software. For location 2067 and more information, read <file:Documentation/power/apm-acpi.txt> 2068 and the Battery Powered Linux mini-HOWTO, available from 2069 <http://www.tldp.org/docs.html#howto>. 2070 2071 This driver does not spin down disk drives (see the hdparm(8) 2072 manpage ("man 8 hdparm") for that), and it doesn't turn off 2073 VESA-compliant "green" monitors. 2074 2075 This driver does not support the TI 4000M TravelMate and the ACER 2076 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2077 desktop machines also don't have compliant BIOSes, and this driver 2078 may cause those machines to panic during the boot phase. 2079 2080 Generally, if you don't have a battery in your machine, there isn't 2081 much point in using this driver and you should say N. If you get 2082 random kernel OOPSes or reboots that don't seem to be related to 2083 anything, try disabling/enabling this option (or disabling/enabling 2084 APM in your BIOS). 2085 2086 Some other things you should try when experiencing seemingly random, 2087 "weird" problems: 2088 2089 1) make sure that you have enough swap space and that it is 2090 enabled. 2091 2) pass the "no-hlt" option to the kernel 2092 3) switch on floating point emulation in the kernel and pass 2093 the "no387" option to the kernel 2094 4) pass the "floppy=nodma" option to the kernel 2095 5) pass the "mem=4M" option to the kernel (thereby disabling 2096 all but the first 4 MB of RAM) 2097 6) make sure that the CPU is not over clocked. 2098 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2099 8) disable the cache from your BIOS settings 2100 9) install a fan for the video card or exchange video RAM 2101 10) install a better fan for the CPU 2102 11) exchange RAM chips 2103 12) exchange the motherboard. 2104 2105 To compile this driver as a module, choose M here: the 2106 module will be called apm. 2107 2108if APM 2109 2110config APM_IGNORE_USER_SUSPEND 2111 bool "Ignore USER SUSPEND" 2112 ---help--- 2113 This option will ignore USER SUSPEND requests. On machines with a 2114 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2115 series notebooks, it is necessary to say Y because of a BIOS bug. 2116 2117config APM_DO_ENABLE 2118 bool "Enable PM at boot time" 2119 ---help--- 2120 Enable APM features at boot time. From page 36 of the APM BIOS 2121 specification: "When disabled, the APM BIOS does not automatically 2122 power manage devices, enter the Standby State, enter the Suspend 2123 State, or take power saving steps in response to CPU Idle calls." 2124 This driver will make CPU Idle calls when Linux is idle (unless this 2125 feature is turned off -- see "Do CPU IDLE calls", below). This 2126 should always save battery power, but more complicated APM features 2127 will be dependent on your BIOS implementation. You may need to turn 2128 this option off if your computer hangs at boot time when using APM 2129 support, or if it beeps continuously instead of suspending. Turn 2130 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2131 T400CDT. This is off by default since most machines do fine without 2132 this feature. 2133 2134config APM_CPU_IDLE 2135 depends on CPU_IDLE 2136 bool "Make CPU Idle calls when idle" 2137 ---help--- 2138 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2139 On some machines, this can activate improved power savings, such as 2140 a slowed CPU clock rate, when the machine is idle. These idle calls 2141 are made after the idle loop has run for some length of time (e.g., 2142 333 mS). On some machines, this will cause a hang at boot time or 2143 whenever the CPU becomes idle. (On machines with more than one CPU, 2144 this option does nothing.) 2145 2146config APM_DISPLAY_BLANK 2147 bool "Enable console blanking using APM" 2148 ---help--- 2149 Enable console blanking using the APM. Some laptops can use this to 2150 turn off the LCD backlight when the screen blanker of the Linux 2151 virtual console blanks the screen. Note that this is only used by 2152 the virtual console screen blanker, and won't turn off the backlight 2153 when using the X Window system. This also doesn't have anything to 2154 do with your VESA-compliant power-saving monitor. Further, this 2155 option doesn't work for all laptops -- it might not turn off your 2156 backlight at all, or it might print a lot of errors to the console, 2157 especially if you are using gpm. 2158 2159config APM_ALLOW_INTS 2160 bool "Allow interrupts during APM BIOS calls" 2161 ---help--- 2162 Normally we disable external interrupts while we are making calls to 2163 the APM BIOS as a measure to lessen the effects of a badly behaving 2164 BIOS implementation. The BIOS should reenable interrupts if it 2165 needs to. Unfortunately, some BIOSes do not -- especially those in 2166 many of the newer IBM Thinkpads. If you experience hangs when you 2167 suspend, try setting this to Y. Otherwise, say N. 2168 2169endif # APM 2170 2171source "drivers/cpufreq/Kconfig" 2172 2173source "drivers/cpuidle/Kconfig" 2174 2175source "drivers/idle/Kconfig" 2176 2177endmenu 2178 2179 2180menu "Bus options (PCI etc.)" 2181 2182config PCI 2183 bool "PCI support" 2184 default y 2185 ---help--- 2186 Find out whether you have a PCI motherboard. PCI is the name of a 2187 bus system, i.e. the way the CPU talks to the other stuff inside 2188 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 2189 VESA. If you have PCI, say Y, otherwise N. 2190 2191choice 2192 prompt "PCI access mode" 2193 depends on X86_32 && PCI 2194 default PCI_GOANY 2195 ---help--- 2196 On PCI systems, the BIOS can be used to detect the PCI devices and 2197 determine their configuration. However, some old PCI motherboards 2198 have BIOS bugs and may crash if this is done. Also, some embedded 2199 PCI-based systems don't have any BIOS at all. Linux can also try to 2200 detect the PCI hardware directly without using the BIOS. 2201 2202 With this option, you can specify how Linux should detect the 2203 PCI devices. If you choose "BIOS", the BIOS will be used, 2204 if you choose "Direct", the BIOS won't be used, and if you 2205 choose "MMConfig", then PCI Express MMCONFIG will be used. 2206 If you choose "Any", the kernel will try MMCONFIG, then the 2207 direct access method and falls back to the BIOS if that doesn't 2208 work. If unsure, go with the default, which is "Any". 2209 2210config PCI_GOBIOS 2211 bool "BIOS" 2212 2213config PCI_GOMMCONFIG 2214 bool "MMConfig" 2215 2216config PCI_GODIRECT 2217 bool "Direct" 2218 2219config PCI_GOOLPC 2220 bool "OLPC XO-1" 2221 depends on OLPC 2222 2223config PCI_GOANY 2224 bool "Any" 2225 2226endchoice 2227 2228config PCI_BIOS 2229 def_bool y 2230 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2231 2232# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2233config PCI_DIRECT 2234 def_bool y 2235 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2236 2237config PCI_MMCONFIG 2238 def_bool y 2239 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY) 2240 2241config PCI_OLPC 2242 def_bool y 2243 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2244 2245config PCI_XEN 2246 def_bool y 2247 depends on PCI && XEN 2248 select SWIOTLB_XEN 2249 2250config PCI_DOMAINS 2251 def_bool y 2252 depends on PCI 2253 2254config PCI_MMCONFIG 2255 bool "Support mmconfig PCI config space access" 2256 depends on X86_64 && PCI && ACPI 2257 2258config PCI_CNB20LE_QUIRK 2259 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2260 depends on PCI 2261 help 2262 Read the PCI windows out of the CNB20LE host bridge. This allows 2263 PCI hotplug to work on systems with the CNB20LE chipset which do 2264 not have ACPI. 2265 2266 There's no public spec for this chipset, and this functionality 2267 is known to be incomplete. 2268 2269 You should say N unless you know you need this. 2270 2271source "drivers/pci/pcie/Kconfig" 2272 2273source "drivers/pci/Kconfig" 2274 2275# x86_64 have no ISA slots, but can have ISA-style DMA. 2276config ISA_DMA_API 2277 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2278 default y 2279 help 2280 Enables ISA-style DMA support for devices requiring such controllers. 2281 If unsure, say Y. 2282 2283if X86_32 2284 2285config ISA 2286 bool "ISA support" 2287 ---help--- 2288 Find out whether you have ISA slots on your motherboard. ISA is the 2289 name of a bus system, i.e. the way the CPU talks to the other stuff 2290 inside your box. Other bus systems are PCI, EISA, MicroChannel 2291 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2292 newer boards don't support it. If you have ISA, say Y, otherwise N. 2293 2294config EISA 2295 bool "EISA support" 2296 depends on ISA 2297 ---help--- 2298 The Extended Industry Standard Architecture (EISA) bus was 2299 developed as an open alternative to the IBM MicroChannel bus. 2300 2301 The EISA bus provided some of the features of the IBM MicroChannel 2302 bus while maintaining backward compatibility with cards made for 2303 the older ISA bus. The EISA bus saw limited use between 1988 and 2304 1995 when it was made obsolete by the PCI bus. 2305 2306 Say Y here if you are building a kernel for an EISA-based machine. 2307 2308 Otherwise, say N. 2309 2310source "drivers/eisa/Kconfig" 2311 2312config SCx200 2313 tristate "NatSemi SCx200 support" 2314 ---help--- 2315 This provides basic support for National Semiconductor's 2316 (now AMD's) Geode processors. The driver probes for the 2317 PCI-IDs of several on-chip devices, so its a good dependency 2318 for other scx200_* drivers. 2319 2320 If compiled as a module, the driver is named scx200. 2321 2322config SCx200HR_TIMER 2323 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2324 depends on SCx200 2325 default y 2326 ---help--- 2327 This driver provides a clocksource built upon the on-chip 2328 27MHz high-resolution timer. Its also a workaround for 2329 NSC Geode SC-1100's buggy TSC, which loses time when the 2330 processor goes idle (as is done by the scheduler). The 2331 other workaround is idle=poll boot option. 2332 2333config OLPC 2334 bool "One Laptop Per Child support" 2335 depends on !X86_PAE 2336 select GPIOLIB 2337 select OF 2338 select OF_PROMTREE 2339 select IRQ_DOMAIN 2340 ---help--- 2341 Add support for detecting the unique features of the OLPC 2342 XO hardware. 2343 2344config OLPC_XO1_PM 2345 bool "OLPC XO-1 Power Management" 2346 depends on OLPC && MFD_CS5535 && PM_SLEEP 2347 select MFD_CORE 2348 ---help--- 2349 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2350 2351config OLPC_XO1_RTC 2352 bool "OLPC XO-1 Real Time Clock" 2353 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2354 ---help--- 2355 Add support for the XO-1 real time clock, which can be used as a 2356 programmable wakeup source. 2357 2358config OLPC_XO1_SCI 2359 bool "OLPC XO-1 SCI extras" 2360 depends on OLPC && OLPC_XO1_PM 2361 depends on INPUT=y 2362 select POWER_SUPPLY 2363 select GPIO_CS5535 2364 select MFD_CORE 2365 ---help--- 2366 Add support for SCI-based features of the OLPC XO-1 laptop: 2367 - EC-driven system wakeups 2368 - Power button 2369 - Ebook switch 2370 - Lid switch 2371 - AC adapter status updates 2372 - Battery status updates 2373 2374config OLPC_XO15_SCI 2375 bool "OLPC XO-1.5 SCI extras" 2376 depends on OLPC && ACPI 2377 select POWER_SUPPLY 2378 ---help--- 2379 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2380 - EC-driven system wakeups 2381 - AC adapter status updates 2382 - Battery status updates 2383 2384config ALIX 2385 bool "PCEngines ALIX System Support (LED setup)" 2386 select GPIOLIB 2387 ---help--- 2388 This option enables system support for the PCEngines ALIX. 2389 At present this just sets up LEDs for GPIO control on 2390 ALIX2/3/6 boards. However, other system specific setup should 2391 get added here. 2392 2393 Note: You must still enable the drivers for GPIO and LED support 2394 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2395 2396 Note: You have to set alix.force=1 for boards with Award BIOS. 2397 2398config NET5501 2399 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2400 select GPIOLIB 2401 ---help--- 2402 This option enables system support for the Soekris Engineering net5501. 2403 2404config GEOS 2405 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2406 select GPIOLIB 2407 depends on DMI 2408 ---help--- 2409 This option enables system support for the Traverse Technologies GEOS. 2410 2411config TS5500 2412 bool "Technologic Systems TS-5500 platform support" 2413 depends on MELAN 2414 select CHECK_SIGNATURE 2415 select NEW_LEDS 2416 select LEDS_CLASS 2417 ---help--- 2418 This option enables system support for the Technologic Systems TS-5500. 2419 2420endif # X86_32 2421 2422config AMD_NB 2423 def_bool y 2424 depends on CPU_SUP_AMD && PCI 2425 2426source "drivers/pcmcia/Kconfig" 2427 2428source "drivers/pci/hotplug/Kconfig" 2429 2430config RAPIDIO 2431 tristate "RapidIO support" 2432 depends on PCI 2433 default n 2434 help 2435 If enabled this option will include drivers and the core 2436 infrastructure code to support RapidIO interconnect devices. 2437 2438source "drivers/rapidio/Kconfig" 2439 2440config X86_SYSFB 2441 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2442 help 2443 Firmwares often provide initial graphics framebuffers so the BIOS, 2444 bootloader or kernel can show basic video-output during boot for 2445 user-guidance and debugging. Historically, x86 used the VESA BIOS 2446 Extensions and EFI-framebuffers for this, which are mostly limited 2447 to x86. 2448 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2449 framebuffers so the new generic system-framebuffer drivers can be 2450 used on x86. If the framebuffer is not compatible with the generic 2451 modes, it is adverticed as fallback platform framebuffer so legacy 2452 drivers like efifb, vesafb and uvesafb can pick it up. 2453 If this option is not selected, all system framebuffers are always 2454 marked as fallback platform framebuffers as usual. 2455 2456 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2457 not be able to pick up generic system framebuffers if this option 2458 is selected. You are highly encouraged to enable simplefb as 2459 replacement if you select this option. simplefb can correctly deal 2460 with generic system framebuffers. But you should still keep vesafb 2461 and others enabled as fallback if a system framebuffer is 2462 incompatible with simplefb. 2463 2464 If unsure, say Y. 2465 2466endmenu 2467 2468 2469menu "Executable file formats / Emulations" 2470 2471source "fs/Kconfig.binfmt" 2472 2473config IA32_EMULATION 2474 bool "IA32 Emulation" 2475 depends on X86_64 2476 select BINFMT_ELF 2477 select COMPAT_BINFMT_ELF 2478 select HAVE_UID16 2479 ---help--- 2480 Include code to run legacy 32-bit programs under a 2481 64-bit kernel. You should likely turn this on, unless you're 2482 100% sure that you don't have any 32-bit programs left. 2483 2484config IA32_AOUT 2485 tristate "IA32 a.out support" 2486 depends on IA32_EMULATION 2487 ---help--- 2488 Support old a.out binaries in the 32bit emulation. 2489 2490config X86_X32 2491 bool "x32 ABI for 64-bit mode" 2492 depends on X86_64 && IA32_EMULATION 2493 ---help--- 2494 Include code to run binaries for the x32 native 32-bit ABI 2495 for 64-bit processors. An x32 process gets access to the 2496 full 64-bit register file and wide data path while leaving 2497 pointers at 32 bits for smaller memory footprint. 2498 2499 You will need a recent binutils (2.22 or later) with 2500 elf32_x86_64 support enabled to compile a kernel with this 2501 option set. 2502 2503config COMPAT 2504 def_bool y 2505 depends on IA32_EMULATION || X86_X32 2506 select ARCH_WANT_OLD_COMPAT_IPC 2507 2508if COMPAT 2509config COMPAT_FOR_U64_ALIGNMENT 2510 def_bool y 2511 2512config SYSVIPC_COMPAT 2513 def_bool y 2514 depends on SYSVIPC 2515 2516config KEYS_COMPAT 2517 def_bool y 2518 depends on KEYS 2519endif 2520 2521endmenu 2522 2523 2524config HAVE_ATOMIC_IOMAP 2525 def_bool y 2526 depends on X86_32 2527 2528config X86_DEV_DMA_OPS 2529 bool 2530 depends on X86_64 || STA2X11 2531 2532config X86_DMA_REMAP 2533 bool 2534 depends on STA2X11 2535 2536config PMC_ATOM 2537 def_bool y 2538 depends on PCI 2539 2540source "net/Kconfig" 2541 2542source "drivers/Kconfig" 2543 2544source "drivers/firmware/Kconfig" 2545 2546source "fs/Kconfig" 2547 2548source "arch/x86/Kconfig.debug" 2549 2550source "security/Kconfig" 2551 2552source "crypto/Kconfig" 2553 2554source "arch/x86/kvm/Kconfig" 2555 2556source "lib/Kconfig" 2557