1# x86 configuration 2mainmenu "Linux Kernel Configuration for x86" 3 4# Select 32 or 64 bit 5config 64BIT 6 bool "64-bit kernel" if ARCH = "x86" 7 default ARCH = "x86_64" 8 help 9 Say yes to build a 64-bit kernel - formerly known as x86_64 10 Say no to build a 32-bit kernel - formerly known as i386 11 12config X86_32 13 def_bool !64BIT 14 15config X86_64 16 def_bool 64BIT 17 18### Arch settings 19config X86 20 def_bool y 21 select HAVE_AOUT if X86_32 22 select HAVE_READQ 23 select HAVE_WRITEQ 24 select HAVE_UNSTABLE_SCHED_CLOCK 25 select HAVE_IDE 26 select HAVE_OPROFILE 27 select HAVE_IOREMAP_PROT 28 select HAVE_KPROBES 29 select ARCH_WANT_OPTIONAL_GPIOLIB 30 select ARCH_WANT_FRAME_POINTERS 31 select HAVE_KRETPROBES 32 select HAVE_FTRACE_MCOUNT_RECORD 33 select HAVE_DYNAMIC_FTRACE 34 select HAVE_FUNCTION_TRACER 35 select HAVE_FUNCTION_GRAPH_TRACER 36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST 37 select HAVE_KVM 38 select HAVE_ARCH_KGDB 39 select HAVE_ARCH_TRACEHOOK 40 select HAVE_GENERIC_DMA_COHERENT if X86_32 41 select HAVE_EFFICIENT_UNALIGNED_ACCESS 42 select USER_STACKTRACE_SUPPORT 43 44config ARCH_DEFCONFIG 45 string 46 default "arch/x86/configs/i386_defconfig" if X86_32 47 default "arch/x86/configs/x86_64_defconfig" if X86_64 48 49config GENERIC_TIME 50 def_bool y 51 52config GENERIC_CMOS_UPDATE 53 def_bool y 54 55config CLOCKSOURCE_WATCHDOG 56 def_bool y 57 58config GENERIC_CLOCKEVENTS 59 def_bool y 60 61config GENERIC_CLOCKEVENTS_BROADCAST 62 def_bool y 63 depends on X86_64 || (X86_32 && X86_LOCAL_APIC) 64 65config LOCKDEP_SUPPORT 66 def_bool y 67 68config STACKTRACE_SUPPORT 69 def_bool y 70 71config HAVE_LATENCYTOP_SUPPORT 72 def_bool y 73 74config FAST_CMPXCHG_LOCAL 75 bool 76 default y 77 78config MMU 79 def_bool y 80 81config ZONE_DMA 82 def_bool y 83 84config SBUS 85 bool 86 87config GENERIC_ISA_DMA 88 def_bool y 89 90config GENERIC_IOMAP 91 def_bool y 92 93config GENERIC_BUG 94 def_bool y 95 depends on BUG 96 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 97 98config GENERIC_BUG_RELATIVE_POINTERS 99 bool 100 101config GENERIC_HWEIGHT 102 def_bool y 103 104config GENERIC_GPIO 105 bool 106 107config ARCH_MAY_HAVE_PC_FDC 108 def_bool y 109 110config RWSEM_GENERIC_SPINLOCK 111 def_bool !X86_XADD 112 113config RWSEM_XCHGADD_ALGORITHM 114 def_bool X86_XADD 115 116config ARCH_HAS_CPU_IDLE_WAIT 117 def_bool y 118 119config GENERIC_CALIBRATE_DELAY 120 def_bool y 121 122config GENERIC_TIME_VSYSCALL 123 bool 124 default X86_64 125 126config ARCH_HAS_CPU_RELAX 127 def_bool y 128 129config ARCH_HAS_DEFAULT_IDLE 130 def_bool y 131 132config ARCH_HAS_CACHE_LINE_SIZE 133 def_bool y 134 135config HAVE_SETUP_PER_CPU_AREA 136 def_bool y 137 138config HAVE_CPUMASK_OF_CPU_MAP 139 def_bool X86_64_SMP 140 141config ARCH_HIBERNATION_POSSIBLE 142 def_bool y 143 depends on !SMP 144 145config ARCH_SUSPEND_POSSIBLE 146 def_bool y 147 148config ZONE_DMA32 149 bool 150 default X86_64 151 152config ARCH_POPULATES_NODE_MAP 153 def_bool y 154 155config AUDIT_ARCH 156 bool 157 default X86_64 158 159config ARCH_SUPPORTS_OPTIMIZED_INLINING 160 def_bool y 161 162# Use the generic interrupt handling code in kernel/irq/: 163config GENERIC_HARDIRQS 164 bool 165 default y 166 167config GENERIC_IRQ_PROBE 168 bool 169 default y 170 171config GENERIC_PENDING_IRQ 172 bool 173 depends on GENERIC_HARDIRQS && SMP 174 default y 175 176config X86_SMP 177 bool 178 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64) 179 default y 180 181config USE_GENERIC_SMP_HELPERS 182 def_bool y 183 depends on SMP 184 185config X86_32_SMP 186 def_bool y 187 depends on X86_32 && SMP 188 189config X86_64_SMP 190 def_bool y 191 depends on X86_64 && SMP 192 193config X86_HT 194 bool 195 depends on SMP 196 depends on (X86_32 && !X86_VOYAGER) || X86_64 197 default y 198 199config X86_BIOS_REBOOT 200 bool 201 depends on !X86_VOYAGER 202 default y 203 204config X86_TRAMPOLINE 205 bool 206 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP) 207 default y 208 209config KTIME_SCALAR 210 def_bool X86_32 211source "init/Kconfig" 212source "kernel/Kconfig.freezer" 213 214menu "Processor type and features" 215 216source "kernel/time/Kconfig" 217 218config SMP 219 bool "Symmetric multi-processing support" 220 ---help--- 221 This enables support for systems with more than one CPU. If you have 222 a system with only one CPU, like most personal computers, say N. If 223 you have a system with more than one CPU, say Y. 224 225 If you say N here, the kernel will run on single and multiprocessor 226 machines, but will use only one CPU of a multiprocessor machine. If 227 you say Y here, the kernel will run on many, but not all, 228 singleprocessor machines. On a singleprocessor machine, the kernel 229 will run faster if you say N here. 230 231 Note that if you say Y here and choose architecture "586" or 232 "Pentium" under "Processor family", the kernel will not work on 486 233 architectures. Similarly, multiprocessor kernels for the "PPro" 234 architecture may not work on all Pentium based boards. 235 236 People using multiprocessor machines who say Y here should also say 237 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 238 Management" code will be disabled if you say Y here. 239 240 See also <file:Documentation/i386/IO-APIC.txt>, 241 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at 242 <http://www.tldp.org/docs.html#howto>. 243 244 If you don't know what to do here, say N. 245 246config X86_HAS_BOOT_CPU_ID 247 def_bool y 248 depends on X86_VOYAGER 249 250config SPARSE_IRQ 251 bool "Support sparse irq numbering" 252 depends on PCI_MSI || HT_IRQ 253 help 254 This enables support for sparse irqs. This is useful for distro 255 kernels that want to define a high CONFIG_NR_CPUS value but still 256 want to have low kernel memory footprint on smaller machines. 257 258 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread 259 out the irq_desc[] array in a more NUMA-friendly way. ) 260 261 If you don't know what to do here, say N. 262 263config NUMA_MIGRATE_IRQ_DESC 264 bool "Move irq desc when changing irq smp_affinity" 265 depends on SPARSE_IRQ && NUMA 266 default n 267 help 268 This enables moving irq_desc to cpu/node that irq will use handled. 269 270 If you don't know what to do here, say N. 271 272config X86_FIND_SMP_CONFIG 273 def_bool y 274 depends on X86_MPPARSE || X86_VOYAGER 275 276config X86_MPPARSE 277 bool "Enable MPS table" if ACPI 278 default y 279 depends on X86_LOCAL_APIC 280 help 281 For old smp systems that do not have proper acpi support. Newer systems 282 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 283 284choice 285 prompt "Subarchitecture Type" 286 default X86_PC 287 288config X86_PC 289 bool "PC-compatible" 290 help 291 Choose this option if your computer is a standard PC or compatible. 292 293config X86_ELAN 294 bool "AMD Elan" 295 depends on X86_32 296 help 297 Select this for an AMD Elan processor. 298 299 Do not use this option for K6/Athlon/Opteron processors! 300 301 If unsure, choose "PC-compatible" instead. 302 303config X86_VOYAGER 304 bool "Voyager (NCR)" 305 depends on X86_32 && SMP && !PCI && BROKEN 306 help 307 Voyager is an MCA-based 32-way capable SMP architecture proprietary 308 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based. 309 310 *** WARNING *** 311 312 If you do not specifically know you have a Voyager based machine, 313 say N here, otherwise the kernel you build will not be bootable. 314 315config X86_GENERICARCH 316 bool "Generic architecture" 317 depends on X86_32 318 help 319 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default 320 subarchitectures. It is intended for a generic binary kernel. 321 if you select them all, kernel will probe it one by one. and will 322 fallback to default. 323 324if X86_GENERICARCH 325 326config X86_NUMAQ 327 bool "NUMAQ (IBM/Sequent)" 328 depends on SMP && X86_32 && PCI && X86_MPPARSE 329 select NUMA 330 help 331 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent) 332 NUMA multiquad box. This changes the way that processors are 333 bootstrapped, and uses Clustered Logical APIC addressing mode instead 334 of Flat Logical. You will need a new lynxer.elf file to flash your 335 firmware with - send email to <Martin.Bligh@us.ibm.com>. 336 337config X86_SUMMIT 338 bool "Summit/EXA (IBM x440)" 339 depends on X86_32 && SMP 340 help 341 This option is needed for IBM systems that use the Summit/EXA chipset. 342 In particular, it is needed for the x440. 343 344config X86_ES7000 345 bool "Support for Unisys ES7000 IA32 series" 346 depends on X86_32 && SMP 347 help 348 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is 349 supposed to run on an IA32-based Unisys ES7000 system. 350 351config X86_BIGSMP 352 bool "Support for big SMP systems with more than 8 CPUs" 353 depends on X86_32 && SMP 354 help 355 This option is needed for the systems that have more than 8 CPUs 356 and if the system is not of any sub-arch type above. 357 358endif 359 360config X86_VSMP 361 bool "Support for ScaleMP vSMP" 362 select PARAVIRT 363 depends on X86_64 && PCI 364 help 365 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 366 supposed to run on these EM64T-based machines. Only choose this option 367 if you have one of these machines. 368 369endchoice 370 371config X86_VISWS 372 bool "SGI 320/540 (Visual Workstation)" 373 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT 374 help 375 The SGI Visual Workstation series is an IA32-based workstation 376 based on SGI systems chips with some legacy PC hardware attached. 377 378 Say Y here to create a kernel to run on the SGI 320 or 540. 379 380 A kernel compiled for the Visual Workstation will run on general 381 PCs as well. See <file:Documentation/sgi-visws.txt> for details. 382 383config X86_RDC321X 384 bool "RDC R-321x SoC" 385 depends on X86_32 386 select M486 387 select X86_REBOOTFIXUPS 388 help 389 This option is needed for RDC R-321x system-on-chip, also known 390 as R-8610-(G). 391 If you don't have one of these chips, you should say N here. 392 393config X86_UV 394 bool "SGI Ultraviolet" 395 depends on X86_64 396 help 397 This option is needed in order to support SGI Ultraviolet systems. 398 If you don't have one of these, you should say N here. 399 400config SCHED_OMIT_FRAME_POINTER 401 def_bool y 402 prompt "Single-depth WCHAN output" 403 depends on X86 404 help 405 Calculate simpler /proc/<PID>/wchan values. If this option 406 is disabled then wchan values will recurse back to the 407 caller function. This provides more accurate wchan values, 408 at the expense of slightly more scheduling overhead. 409 410 If in doubt, say "Y". 411 412menuconfig PARAVIRT_GUEST 413 bool "Paravirtualized guest support" 414 help 415 Say Y here to get to see options related to running Linux under 416 various hypervisors. This option alone does not add any kernel code. 417 418 If you say N, all options in this submenu will be skipped and disabled. 419 420if PARAVIRT_GUEST 421 422source "arch/x86/xen/Kconfig" 423 424config VMI 425 bool "VMI Guest support" 426 select PARAVIRT 427 depends on X86_32 428 depends on !X86_VOYAGER 429 help 430 VMI provides a paravirtualized interface to the VMware ESX server 431 (it could be used by other hypervisors in theory too, but is not 432 at the moment), by linking the kernel to a GPL-ed ROM module 433 provided by the hypervisor. 434 435config KVM_CLOCK 436 bool "KVM paravirtualized clock" 437 select PARAVIRT 438 select PARAVIRT_CLOCK 439 depends on !X86_VOYAGER 440 help 441 Turning on this option will allow you to run a paravirtualized clock 442 when running over the KVM hypervisor. Instead of relying on a PIT 443 (or probably other) emulation by the underlying device model, the host 444 provides the guest with timing infrastructure such as time of day, and 445 system time 446 447config KVM_GUEST 448 bool "KVM Guest support" 449 select PARAVIRT 450 depends on !X86_VOYAGER 451 help 452 This option enables various optimizations for running under the KVM 453 hypervisor. 454 455source "arch/x86/lguest/Kconfig" 456 457config PARAVIRT 458 bool "Enable paravirtualization code" 459 depends on !X86_VOYAGER 460 help 461 This changes the kernel so it can modify itself when it is run 462 under a hypervisor, potentially improving performance significantly 463 over full virtualization. However, when run without a hypervisor 464 the kernel is theoretically slower and slightly larger. 465 466config PARAVIRT_CLOCK 467 bool 468 default n 469 470endif 471 472config PARAVIRT_DEBUG 473 bool "paravirt-ops debugging" 474 depends on PARAVIRT && DEBUG_KERNEL 475 help 476 Enable to debug paravirt_ops internals. Specifically, BUG if 477 a paravirt_op is missing when it is called. 478 479config MEMTEST 480 bool "Memtest" 481 help 482 This option adds a kernel parameter 'memtest', which allows memtest 483 to be set. 484 memtest=0, mean disabled; -- default 485 memtest=1, mean do 1 test pattern; 486 ... 487 memtest=4, mean do 4 test patterns. 488 If you are unsure how to answer this question, answer N. 489 490config X86_SUMMIT_NUMA 491 def_bool y 492 depends on X86_32 && NUMA && X86_GENERICARCH 493 494config X86_CYCLONE_TIMER 495 def_bool y 496 depends on X86_GENERICARCH 497 498source "arch/x86/Kconfig.cpu" 499 500config HPET_TIMER 501 def_bool X86_64 502 prompt "HPET Timer Support" if X86_32 503 help 504 Use the IA-PC HPET (High Precision Event Timer) to manage 505 time in preference to the PIT and RTC, if a HPET is 506 present. 507 HPET is the next generation timer replacing legacy 8254s. 508 The HPET provides a stable time base on SMP 509 systems, unlike the TSC, but it is more expensive to access, 510 as it is off-chip. You can find the HPET spec at 511 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>. 512 513 You can safely choose Y here. However, HPET will only be 514 activated if the platform and the BIOS support this feature. 515 Otherwise the 8254 will be used for timing services. 516 517 Choose N to continue using the legacy 8254 timer. 518 519config HPET_EMULATE_RTC 520 def_bool y 521 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 522 523# Mark as embedded because too many people got it wrong. 524# The code disables itself when not needed. 525config DMI 526 default y 527 bool "Enable DMI scanning" if EMBEDDED 528 help 529 Enabled scanning of DMI to identify machine quirks. Say Y 530 here unless you have verified that your setup is not 531 affected by entries in the DMI blacklist. Required by PNP 532 BIOS code. 533 534config GART_IOMMU 535 bool "GART IOMMU support" if EMBEDDED 536 default y 537 select SWIOTLB 538 select AGP 539 depends on X86_64 && PCI 540 help 541 Support for full DMA access of devices with 32bit memory access only 542 on systems with more than 3GB. This is usually needed for USB, 543 sound, many IDE/SATA chipsets and some other devices. 544 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART 545 based hardware IOMMU and a software bounce buffer based IOMMU used 546 on Intel systems and as fallback. 547 The code is only active when needed (enough memory and limited 548 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified 549 too. 550 551config CALGARY_IOMMU 552 bool "IBM Calgary IOMMU support" 553 select SWIOTLB 554 depends on X86_64 && PCI && EXPERIMENTAL 555 help 556 Support for hardware IOMMUs in IBM's xSeries x366 and x460 557 systems. Needed to run systems with more than 3GB of memory 558 properly with 32-bit PCI devices that do not support DAC 559 (Double Address Cycle). Calgary also supports bus level 560 isolation, where all DMAs pass through the IOMMU. This 561 prevents them from going anywhere except their intended 562 destination. This catches hard-to-find kernel bugs and 563 mis-behaving drivers and devices that do not use the DMA-API 564 properly to set up their DMA buffers. The IOMMU can be 565 turned off at boot time with the iommu=off parameter. 566 Normally the kernel will make the right choice by itself. 567 If unsure, say Y. 568 569config CALGARY_IOMMU_ENABLED_BY_DEFAULT 570 def_bool y 571 prompt "Should Calgary be enabled by default?" 572 depends on CALGARY_IOMMU 573 help 574 Should Calgary be enabled by default? if you choose 'y', Calgary 575 will be used (if it exists). If you choose 'n', Calgary will not be 576 used even if it exists. If you choose 'n' and would like to use 577 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 578 If unsure, say Y. 579 580config AMD_IOMMU 581 bool "AMD IOMMU support" 582 select SWIOTLB 583 select PCI_MSI 584 depends on X86_64 && PCI && ACPI 585 help 586 With this option you can enable support for AMD IOMMU hardware in 587 your system. An IOMMU is a hardware component which provides 588 remapping of DMA memory accesses from devices. With an AMD IOMMU you 589 can isolate the the DMA memory of different devices and protect the 590 system from misbehaving device drivers or hardware. 591 592 You can find out if your system has an AMD IOMMU if you look into 593 your BIOS for an option to enable it or if you have an IVRS ACPI 594 table. 595 596config AMD_IOMMU_STATS 597 bool "Export AMD IOMMU statistics to debugfs" 598 depends on AMD_IOMMU 599 select DEBUG_FS 600 help 601 This option enables code in the AMD IOMMU driver to collect various 602 statistics about whats happening in the driver and exports that 603 information to userspace via debugfs. 604 If unsure, say N. 605 606# need this always selected by IOMMU for the VIA workaround 607config SWIOTLB 608 def_bool y if X86_64 609 help 610 Support for software bounce buffers used on x86-64 systems 611 which don't have a hardware IOMMU (e.g. the current generation 612 of Intel's x86-64 CPUs). Using this PCI devices which can only 613 access 32-bits of memory can be used on systems with more than 614 3 GB of memory. If unsure, say Y. 615 616config IOMMU_HELPER 617 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU) 618 619config IOMMU_API 620 def_bool (AMD_IOMMU || DMAR) 621 622config MAXSMP 623 bool "Configure Maximum number of SMP Processors and NUMA Nodes" 624 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL 625 select CPUMASK_OFFSTACK 626 default n 627 help 628 Configure maximum number of CPUS and NUMA Nodes for this architecture. 629 If unsure, say N. 630 631config NR_CPUS 632 int "Maximum number of CPUs" if SMP && !MAXSMP 633 range 2 512 if SMP && !MAXSMP 634 default "1" if !SMP 635 default "4096" if MAXSMP 636 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000) 637 default "8" if SMP 638 help 639 This allows you to specify the maximum number of CPUs which this 640 kernel will support. The maximum supported value is 512 and the 641 minimum value which makes sense is 2. 642 643 This is purely to save memory - each supported CPU adds 644 approximately eight kilobytes to the kernel image. 645 646config SCHED_SMT 647 bool "SMT (Hyperthreading) scheduler support" 648 depends on X86_HT 649 help 650 SMT scheduler support improves the CPU scheduler's decision making 651 when dealing with Intel Pentium 4 chips with HyperThreading at a 652 cost of slightly increased overhead in some places. If unsure say 653 N here. 654 655config SCHED_MC 656 def_bool y 657 prompt "Multi-core scheduler support" 658 depends on X86_HT 659 help 660 Multi-core scheduler support improves the CPU scheduler's decision 661 making when dealing with multi-core CPU chips at a cost of slightly 662 increased overhead in some places. If unsure say N here. 663 664source "kernel/Kconfig.preempt" 665 666config X86_UP_APIC 667 bool "Local APIC support on uniprocessors" 668 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH) 669 help 670 A local APIC (Advanced Programmable Interrupt Controller) is an 671 integrated interrupt controller in the CPU. If you have a single-CPU 672 system which has a processor with a local APIC, you can say Y here to 673 enable and use it. If you say Y here even though your machine doesn't 674 have a local APIC, then the kernel will still run with no slowdown at 675 all. The local APIC supports CPU-generated self-interrupts (timer, 676 performance counters), and the NMI watchdog which detects hard 677 lockups. 678 679config X86_UP_IOAPIC 680 bool "IO-APIC support on uniprocessors" 681 depends on X86_UP_APIC 682 help 683 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 684 SMP-capable replacement for PC-style interrupt controllers. Most 685 SMP systems and many recent uniprocessor systems have one. 686 687 If you have a single-CPU system with an IO-APIC, you can say Y here 688 to use it. If you say Y here even though your machine doesn't have 689 an IO-APIC, then the kernel will still run with no slowdown at all. 690 691config X86_LOCAL_APIC 692 def_bool y 693 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH)) 694 695config X86_IO_APIC 696 def_bool y 697 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH)) 698 699config X86_VISWS_APIC 700 def_bool y 701 depends on X86_32 && X86_VISWS 702 703config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 704 bool "Reroute for broken boot IRQs" 705 default n 706 depends on X86_IO_APIC 707 help 708 This option enables a workaround that fixes a source of 709 spurious interrupts. This is recommended when threaded 710 interrupt handling is used on systems where the generation of 711 superfluous "boot interrupts" cannot be disabled. 712 713 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 714 entry in the chipset's IO-APIC is masked (as, e.g. the RT 715 kernel does during interrupt handling). On chipsets where this 716 boot IRQ generation cannot be disabled, this workaround keeps 717 the original IRQ line masked so that only the equivalent "boot 718 IRQ" is delivered to the CPUs. The workaround also tells the 719 kernel to set up the IRQ handler on the boot IRQ line. In this 720 way only one interrupt is delivered to the kernel. Otherwise 721 the spurious second interrupt may cause the kernel to bring 722 down (vital) interrupt lines. 723 724 Only affects "broken" chipsets. Interrupt sharing may be 725 increased on these systems. 726 727config X86_MCE 728 bool "Machine Check Exception" 729 depends on !X86_VOYAGER 730 ---help--- 731 Machine Check Exception support allows the processor to notify the 732 kernel if it detects a problem (e.g. overheating, component failure). 733 The action the kernel takes depends on the severity of the problem, 734 ranging from a warning message on the console, to halting the machine. 735 Your processor must be a Pentium or newer to support this - check the 736 flags in /proc/cpuinfo for mce. Note that some older Pentium systems 737 have a design flaw which leads to false MCE events - hence MCE is 738 disabled on all P5 processors, unless explicitly enabled with "mce" 739 as a boot argument. Similarly, if MCE is built in and creates a 740 problem on some new non-standard machine, you can boot with "nomce" 741 to disable it. MCE support simply ignores non-MCE processors like 742 the 386 and 486, so nearly everyone can say Y here. 743 744config X86_MCE_INTEL 745 def_bool y 746 prompt "Intel MCE features" 747 depends on X86_64 && X86_MCE && X86_LOCAL_APIC 748 help 749 Additional support for intel specific MCE features such as 750 the thermal monitor. 751 752config X86_MCE_AMD 753 def_bool y 754 prompt "AMD MCE features" 755 depends on X86_64 && X86_MCE && X86_LOCAL_APIC 756 help 757 Additional support for AMD specific MCE features such as 758 the DRAM Error Threshold. 759 760config X86_MCE_NONFATAL 761 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4" 762 depends on X86_32 && X86_MCE 763 help 764 Enabling this feature starts a timer that triggers every 5 seconds which 765 will look at the machine check registers to see if anything happened. 766 Non-fatal problems automatically get corrected (but still logged). 767 Disable this if you don't want to see these messages. 768 Seeing the messages this option prints out may be indicative of dying 769 or out-of-spec (ie, overclocked) hardware. 770 This option only does something on certain CPUs. 771 (AMD Athlon/Duron and Intel Pentium 4) 772 773config X86_MCE_P4THERMAL 774 bool "check for P4 thermal throttling interrupt." 775 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP) 776 help 777 Enabling this feature will cause a message to be printed when the P4 778 enters thermal throttling. 779 780config VM86 781 bool "Enable VM86 support" if EMBEDDED 782 default y 783 depends on X86_32 784 help 785 This option is required by programs like DOSEMU to run 16-bit legacy 786 code on X86 processors. It also may be needed by software like 787 XFree86 to initialize some video cards via BIOS. Disabling this 788 option saves about 6k. 789 790config TOSHIBA 791 tristate "Toshiba Laptop support" 792 depends on X86_32 793 ---help--- 794 This adds a driver to safely access the System Management Mode of 795 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 796 not work on models with a Phoenix BIOS. The System Management Mode 797 is used to set the BIOS and power saving options on Toshiba portables. 798 799 For information on utilities to make use of this driver see the 800 Toshiba Linux utilities web site at: 801 <http://www.buzzard.org.uk/toshiba/>. 802 803 Say Y if you intend to run this kernel on a Toshiba portable. 804 Say N otherwise. 805 806config I8K 807 tristate "Dell laptop support" 808 ---help--- 809 This adds a driver to safely access the System Management Mode 810 of the CPU on the Dell Inspiron 8000. The System Management Mode 811 is used to read cpu temperature and cooling fan status and to 812 control the fans on the I8K portables. 813 814 This driver has been tested only on the Inspiron 8000 but it may 815 also work with other Dell laptops. You can force loading on other 816 models by passing the parameter `force=1' to the module. Use at 817 your own risk. 818 819 For information on utilities to make use of this driver see the 820 I8K Linux utilities web site at: 821 <http://people.debian.org/~dz/i8k/> 822 823 Say Y if you intend to run this kernel on a Dell Inspiron 8000. 824 Say N otherwise. 825 826config X86_REBOOTFIXUPS 827 bool "Enable X86 board specific fixups for reboot" 828 depends on X86_32 829 ---help--- 830 This enables chipset and/or board specific fixups to be done 831 in order to get reboot to work correctly. This is only needed on 832 some combinations of hardware and BIOS. The symptom, for which 833 this config is intended, is when reboot ends with a stalled/hung 834 system. 835 836 Currently, the only fixup is for the Geode machines using 837 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 838 839 Say Y if you want to enable the fixup. Currently, it's safe to 840 enable this option even if you don't need it. 841 Say N otherwise. 842 843config MICROCODE 844 tristate "/dev/cpu/microcode - microcode support" 845 select FW_LOADER 846 ---help--- 847 If you say Y here, you will be able to update the microcode on 848 certain Intel and AMD processors. The Intel support is for the 849 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, 850 Pentium 4, Xeon etc. The AMD support is for family 0x10 and 851 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra. 852 You will obviously need the actual microcode binary data itself 853 which is not shipped with the Linux kernel. 854 855 This option selects the general module only, you need to select 856 at least one vendor specific module as well. 857 858 To compile this driver as a module, choose M here: the 859 module will be called microcode. 860 861config MICROCODE_INTEL 862 bool "Intel microcode patch loading support" 863 depends on MICROCODE 864 default MICROCODE 865 select FW_LOADER 866 --help--- 867 This options enables microcode patch loading support for Intel 868 processors. 869 870 For latest news and information on obtaining all the required 871 Intel ingredients for this driver, check: 872 <http://www.urbanmyth.org/microcode/>. 873 874config MICROCODE_AMD 875 bool "AMD microcode patch loading support" 876 depends on MICROCODE 877 select FW_LOADER 878 --help--- 879 If you select this option, microcode patch loading support for AMD 880 processors will be enabled. 881 882 config MICROCODE_OLD_INTERFACE 883 def_bool y 884 depends on MICROCODE 885 886config X86_MSR 887 tristate "/dev/cpu/*/msr - Model-specific register support" 888 help 889 This device gives privileged processes access to the x86 890 Model-Specific Registers (MSRs). It is a character device with 891 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 892 MSR accesses are directed to a specific CPU on multi-processor 893 systems. 894 895config X86_CPUID 896 tristate "/dev/cpu/*/cpuid - CPU information support" 897 help 898 This device gives processes access to the x86 CPUID instruction to 899 be executed on a specific processor. It is a character device 900 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 901 /dev/cpu/31/cpuid. 902 903choice 904 prompt "High Memory Support" 905 default HIGHMEM4G if !X86_NUMAQ 906 default HIGHMEM64G if X86_NUMAQ 907 depends on X86_32 908 909config NOHIGHMEM 910 bool "off" 911 depends on !X86_NUMAQ 912 ---help--- 913 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 914 However, the address space of 32-bit x86 processors is only 4 915 Gigabytes large. That means that, if you have a large amount of 916 physical memory, not all of it can be "permanently mapped" by the 917 kernel. The physical memory that's not permanently mapped is called 918 "high memory". 919 920 If you are compiling a kernel which will never run on a machine with 921 more than 1 Gigabyte total physical RAM, answer "off" here (default 922 choice and suitable for most users). This will result in a "3GB/1GB" 923 split: 3GB are mapped so that each process sees a 3GB virtual memory 924 space and the remaining part of the 4GB virtual memory space is used 925 by the kernel to permanently map as much physical memory as 926 possible. 927 928 If the machine has between 1 and 4 Gigabytes physical RAM, then 929 answer "4GB" here. 930 931 If more than 4 Gigabytes is used then answer "64GB" here. This 932 selection turns Intel PAE (Physical Address Extension) mode on. 933 PAE implements 3-level paging on IA32 processors. PAE is fully 934 supported by Linux, PAE mode is implemented on all recent Intel 935 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 936 then the kernel will not boot on CPUs that don't support PAE! 937 938 The actual amount of total physical memory will either be 939 auto detected or can be forced by using a kernel command line option 940 such as "mem=256M". (Try "man bootparam" or see the documentation of 941 your boot loader (lilo or loadlin) about how to pass options to the 942 kernel at boot time.) 943 944 If unsure, say "off". 945 946config HIGHMEM4G 947 bool "4GB" 948 depends on !X86_NUMAQ 949 help 950 Select this if you have a 32-bit processor and between 1 and 4 951 gigabytes of physical RAM. 952 953config HIGHMEM64G 954 bool "64GB" 955 depends on !M386 && !M486 956 select X86_PAE 957 help 958 Select this if you have a 32-bit processor and more than 4 959 gigabytes of physical RAM. 960 961endchoice 962 963choice 964 depends on EXPERIMENTAL 965 prompt "Memory split" if EMBEDDED 966 default VMSPLIT_3G 967 depends on X86_32 968 help 969 Select the desired split between kernel and user memory. 970 971 If the address range available to the kernel is less than the 972 physical memory installed, the remaining memory will be available 973 as "high memory". Accessing high memory is a little more costly 974 than low memory, as it needs to be mapped into the kernel first. 975 Note that increasing the kernel address space limits the range 976 available to user programs, making the address space there 977 tighter. Selecting anything other than the default 3G/1G split 978 will also likely make your kernel incompatible with binary-only 979 kernel modules. 980 981 If you are not absolutely sure what you are doing, leave this 982 option alone! 983 984 config VMSPLIT_3G 985 bool "3G/1G user/kernel split" 986 config VMSPLIT_3G_OPT 987 depends on !X86_PAE 988 bool "3G/1G user/kernel split (for full 1G low memory)" 989 config VMSPLIT_2G 990 bool "2G/2G user/kernel split" 991 config VMSPLIT_2G_OPT 992 depends on !X86_PAE 993 bool "2G/2G user/kernel split (for full 2G low memory)" 994 config VMSPLIT_1G 995 bool "1G/3G user/kernel split" 996endchoice 997 998config PAGE_OFFSET 999 hex 1000 default 0xB0000000 if VMSPLIT_3G_OPT 1001 default 0x80000000 if VMSPLIT_2G 1002 default 0x78000000 if VMSPLIT_2G_OPT 1003 default 0x40000000 if VMSPLIT_1G 1004 default 0xC0000000 1005 depends on X86_32 1006 1007config HIGHMEM 1008 def_bool y 1009 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1010 1011config X86_PAE 1012 bool "PAE (Physical Address Extension) Support" 1013 depends on X86_32 && !HIGHMEM4G 1014 help 1015 PAE is required for NX support, and furthermore enables 1016 larger swapspace support for non-overcommit purposes. It 1017 has the cost of more pagetable lookup overhead, and also 1018 consumes more pagetable space per process. 1019 1020config ARCH_PHYS_ADDR_T_64BIT 1021 def_bool X86_64 || X86_PAE 1022 1023config DIRECT_GBPAGES 1024 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED 1025 default y 1026 depends on X86_64 1027 help 1028 Allow the kernel linear mapping to use 1GB pages on CPUs that 1029 support it. This can improve the kernel's performance a tiny bit by 1030 reducing TLB pressure. If in doubt, say "Y". 1031 1032# Common NUMA Features 1033config NUMA 1034 bool "Numa Memory Allocation and Scheduler Support" 1035 depends on SMP 1036 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL) 1037 default n if X86_PC 1038 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP) 1039 help 1040 Enable NUMA (Non Uniform Memory Access) support. 1041 1042 The kernel will try to allocate memory used by a CPU on the 1043 local memory controller of the CPU and add some more 1044 NUMA awareness to the kernel. 1045 1046 For 64-bit this is recommended if the system is Intel Core i7 1047 (or later), AMD Opteron, or EM64T NUMA. 1048 1049 For 32-bit this is only needed on (rare) 32-bit-only platforms 1050 that support NUMA topologies, such as NUMAQ / Summit, or if you 1051 boot a 32-bit kernel on a 64-bit NUMA platform. 1052 1053 Otherwise, you should say N. 1054 1055comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI" 1056 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI) 1057 1058config K8_NUMA 1059 def_bool y 1060 prompt "Old style AMD Opteron NUMA detection" 1061 depends on X86_64 && NUMA && PCI 1062 help 1063 Enable K8 NUMA node topology detection. You should say Y here if 1064 you have a multi processor AMD K8 system. This uses an old 1065 method to read the NUMA configuration directly from the builtin 1066 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA 1067 instead, which also takes priority if both are compiled in. 1068 1069config X86_64_ACPI_NUMA 1070 def_bool y 1071 prompt "ACPI NUMA detection" 1072 depends on X86_64 && NUMA && ACPI && PCI 1073 select ACPI_NUMA 1074 help 1075 Enable ACPI SRAT based node topology detection. 1076 1077# Some NUMA nodes have memory ranges that span 1078# other nodes. Even though a pfn is valid and 1079# between a node's start and end pfns, it may not 1080# reside on that node. See memmap_init_zone() 1081# for details. 1082config NODES_SPAN_OTHER_NODES 1083 def_bool y 1084 depends on X86_64_ACPI_NUMA 1085 1086config NUMA_EMU 1087 bool "NUMA emulation" 1088 depends on X86_64 && NUMA 1089 help 1090 Enable NUMA emulation. A flat machine will be split 1091 into virtual nodes when booted with "numa=fake=N", where N is the 1092 number of nodes. This is only useful for debugging. 1093 1094config NODES_SHIFT 1095 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1096 range 1 9 if X86_64 1097 default "9" if MAXSMP 1098 default "6" if X86_64 1099 default "4" if X86_NUMAQ 1100 default "3" 1101 depends on NEED_MULTIPLE_NODES 1102 help 1103 Specify the maximum number of NUMA Nodes available on the target 1104 system. Increases memory reserved to accomodate various tables. 1105 1106config HAVE_ARCH_BOOTMEM_NODE 1107 def_bool y 1108 depends on X86_32 && NUMA 1109 1110config ARCH_HAVE_MEMORY_PRESENT 1111 def_bool y 1112 depends on X86_32 && DISCONTIGMEM 1113 1114config NEED_NODE_MEMMAP_SIZE 1115 def_bool y 1116 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM) 1117 1118config HAVE_ARCH_ALLOC_REMAP 1119 def_bool y 1120 depends on X86_32 && NUMA 1121 1122config ARCH_FLATMEM_ENABLE 1123 def_bool y 1124 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA 1125 1126config ARCH_DISCONTIGMEM_ENABLE 1127 def_bool y 1128 depends on NUMA && X86_32 1129 1130config ARCH_DISCONTIGMEM_DEFAULT 1131 def_bool y 1132 depends on NUMA && X86_32 1133 1134config ARCH_SPARSEMEM_DEFAULT 1135 def_bool y 1136 depends on X86_64 1137 1138config ARCH_SPARSEMEM_ENABLE 1139 def_bool y 1140 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH 1141 select SPARSEMEM_STATIC if X86_32 1142 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1143 1144config ARCH_SELECT_MEMORY_MODEL 1145 def_bool y 1146 depends on ARCH_SPARSEMEM_ENABLE 1147 1148config ARCH_MEMORY_PROBE 1149 def_bool X86_64 1150 depends on MEMORY_HOTPLUG 1151 1152source "mm/Kconfig" 1153 1154config HIGHPTE 1155 bool "Allocate 3rd-level pagetables from highmem" 1156 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G) 1157 help 1158 The VM uses one page table entry for each page of physical memory. 1159 For systems with a lot of RAM, this can be wasteful of precious 1160 low memory. Setting this option will put user-space page table 1161 entries in high memory. 1162 1163config X86_CHECK_BIOS_CORRUPTION 1164 bool "Check for low memory corruption" 1165 help 1166 Periodically check for memory corruption in low memory, which 1167 is suspected to be caused by BIOS. Even when enabled in the 1168 configuration, it is disabled at runtime. Enable it by 1169 setting "memory_corruption_check=1" on the kernel command 1170 line. By default it scans the low 64k of memory every 60 1171 seconds; see the memory_corruption_check_size and 1172 memory_corruption_check_period parameters in 1173 Documentation/kernel-parameters.txt to adjust this. 1174 1175 When enabled with the default parameters, this option has 1176 almost no overhead, as it reserves a relatively small amount 1177 of memory and scans it infrequently. It both detects corruption 1178 and prevents it from affecting the running system. 1179 1180 It is, however, intended as a diagnostic tool; if repeatable 1181 BIOS-originated corruption always affects the same memory, 1182 you can use memmap= to prevent the kernel from using that 1183 memory. 1184 1185config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1186 bool "Set the default setting of memory_corruption_check" 1187 depends on X86_CHECK_BIOS_CORRUPTION 1188 default y 1189 help 1190 Set whether the default state of memory_corruption_check is 1191 on or off. 1192 1193config X86_RESERVE_LOW_64K 1194 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen" 1195 default y 1196 help 1197 Reserve the first 64K of physical RAM on BIOSes that are known 1198 to potentially corrupt that memory range. A numbers of BIOSes are 1199 known to utilize this area during suspend/resume, so it must not 1200 be used by the kernel. 1201 1202 Set this to N if you are absolutely sure that you trust the BIOS 1203 to get all its memory reservations and usages right. 1204 1205 If you have doubts about the BIOS (e.g. suspend/resume does not 1206 work or there's kernel crashes after certain hardware hotplug 1207 events) and it's not AMI or Phoenix, then you might want to enable 1208 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical 1209 corruption patterns. 1210 1211 Say Y if unsure. 1212 1213config MATH_EMULATION 1214 bool 1215 prompt "Math emulation" if X86_32 1216 ---help--- 1217 Linux can emulate a math coprocessor (used for floating point 1218 operations) if you don't have one. 486DX and Pentium processors have 1219 a math coprocessor built in, 486SX and 386 do not, unless you added 1220 a 487DX or 387, respectively. (The messages during boot time can 1221 give you some hints here ["man dmesg"].) Everyone needs either a 1222 coprocessor or this emulation. 1223 1224 If you don't have a math coprocessor, you need to say Y here; if you 1225 say Y here even though you have a coprocessor, the coprocessor will 1226 be used nevertheless. (This behavior can be changed with the kernel 1227 command line option "no387", which comes handy if your coprocessor 1228 is broken. Try "man bootparam" or see the documentation of your boot 1229 loader (lilo or loadlin) about how to pass options to the kernel at 1230 boot time.) This means that it is a good idea to say Y here if you 1231 intend to use this kernel on different machines. 1232 1233 More information about the internals of the Linux math coprocessor 1234 emulation can be found in <file:arch/x86/math-emu/README>. 1235 1236 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1237 kernel, it won't hurt. 1238 1239config MTRR 1240 bool "MTRR (Memory Type Range Register) support" 1241 ---help--- 1242 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1243 the Memory Type Range Registers (MTRRs) may be used to control 1244 processor access to memory ranges. This is most useful if you have 1245 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1246 allows bus write transfers to be combined into a larger transfer 1247 before bursting over the PCI/AGP bus. This can increase performance 1248 of image write operations 2.5 times or more. Saying Y here creates a 1249 /proc/mtrr file which may be used to manipulate your processor's 1250 MTRRs. Typically the X server should use this. 1251 1252 This code has a reasonably generic interface so that similar 1253 control registers on other processors can be easily supported 1254 as well: 1255 1256 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1257 Registers (ARRs) which provide a similar functionality to MTRRs. For 1258 these, the ARRs are used to emulate the MTRRs. 1259 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1260 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1261 write-combining. All of these processors are supported by this code 1262 and it makes sense to say Y here if you have one of them. 1263 1264 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1265 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1266 can lead to all sorts of problems, so it's good to say Y here. 1267 1268 You can safely say Y even if your machine doesn't have MTRRs, you'll 1269 just add about 9 KB to your kernel. 1270 1271 See <file:Documentation/x86/mtrr.txt> for more information. 1272 1273config MTRR_SANITIZER 1274 def_bool y 1275 prompt "MTRR cleanup support" 1276 depends on MTRR 1277 help 1278 Convert MTRR layout from continuous to discrete, so X drivers can 1279 add writeback entries. 1280 1281 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1282 The largest mtrr entry size for a continous block can be set with 1283 mtrr_chunk_size. 1284 1285 If unsure, say Y. 1286 1287config MTRR_SANITIZER_ENABLE_DEFAULT 1288 int "MTRR cleanup enable value (0-1)" 1289 range 0 1 1290 default "0" 1291 depends on MTRR_SANITIZER 1292 help 1293 Enable mtrr cleanup default value 1294 1295config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1296 int "MTRR cleanup spare reg num (0-7)" 1297 range 0 7 1298 default "1" 1299 depends on MTRR_SANITIZER 1300 help 1301 mtrr cleanup spare entries default, it can be changed via 1302 mtrr_spare_reg_nr=N on the kernel command line. 1303 1304config X86_PAT 1305 bool 1306 prompt "x86 PAT support" 1307 depends on MTRR 1308 help 1309 Use PAT attributes to setup page level cache control. 1310 1311 PATs are the modern equivalents of MTRRs and are much more 1312 flexible than MTRRs. 1313 1314 Say N here if you see bootup problems (boot crash, boot hang, 1315 spontaneous reboots) or a non-working video driver. 1316 1317 If unsure, say Y. 1318 1319config EFI 1320 bool "EFI runtime service support" 1321 depends on ACPI 1322 ---help--- 1323 This enables the kernel to use EFI runtime services that are 1324 available (such as the EFI variable services). 1325 1326 This option is only useful on systems that have EFI firmware. 1327 In addition, you should use the latest ELILO loader available 1328 at <http://elilo.sourceforge.net> in order to take advantage 1329 of EFI runtime services. However, even with this option, the 1330 resultant kernel should continue to boot on existing non-EFI 1331 platforms. 1332 1333config SECCOMP 1334 def_bool y 1335 prompt "Enable seccomp to safely compute untrusted bytecode" 1336 help 1337 This kernel feature is useful for number crunching applications 1338 that may need to compute untrusted bytecode during their 1339 execution. By using pipes or other transports made available to 1340 the process as file descriptors supporting the read/write 1341 syscalls, it's possible to isolate those applications in 1342 their own address space using seccomp. Once seccomp is 1343 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1344 and the task is only allowed to execute a few safe syscalls 1345 defined by each seccomp mode. 1346 1347 If unsure, say Y. Only embedded should say N here. 1348 1349config CC_STACKPROTECTOR_ALL 1350 bool 1351 1352config CC_STACKPROTECTOR 1353 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)" 1354 depends on X86_64 1355 select CC_STACKPROTECTOR_ALL 1356 help 1357 This option turns on the -fstack-protector GCC feature. This 1358 feature puts, at the beginning of functions, a canary value on 1359 the stack just before the return address, and validates 1360 the value just before actually returning. Stack based buffer 1361 overflows (that need to overwrite this return address) now also 1362 overwrite the canary, which gets detected and the attack is then 1363 neutralized via a kernel panic. 1364 1365 This feature requires gcc version 4.2 or above, or a distribution 1366 gcc with the feature backported. Older versions are automatically 1367 detected and for those versions, this configuration option is 1368 ignored. (and a warning is printed during bootup) 1369 1370source kernel/Kconfig.hz 1371 1372config KEXEC 1373 bool "kexec system call" 1374 depends on X86_BIOS_REBOOT 1375 help 1376 kexec is a system call that implements the ability to shutdown your 1377 current kernel, and to start another kernel. It is like a reboot 1378 but it is independent of the system firmware. And like a reboot 1379 you can start any kernel with it, not just Linux. 1380 1381 The name comes from the similarity to the exec system call. 1382 1383 It is an ongoing process to be certain the hardware in a machine 1384 is properly shutdown, so do not be surprised if this code does not 1385 initially work for you. It may help to enable device hotplugging 1386 support. As of this writing the exact hardware interface is 1387 strongly in flux, so no good recommendation can be made. 1388 1389config CRASH_DUMP 1390 bool "kernel crash dumps" 1391 depends on X86_64 || (X86_32 && HIGHMEM) 1392 help 1393 Generate crash dump after being started by kexec. 1394 This should be normally only set in special crash dump kernels 1395 which are loaded in the main kernel with kexec-tools into 1396 a specially reserved region and then later executed after 1397 a crash by kdump/kexec. The crash dump kernel must be compiled 1398 to a memory address not used by the main kernel or BIOS using 1399 PHYSICAL_START, or it must be built as a relocatable image 1400 (CONFIG_RELOCATABLE=y). 1401 For more details see Documentation/kdump/kdump.txt 1402 1403config KEXEC_JUMP 1404 bool "kexec jump (EXPERIMENTAL)" 1405 depends on EXPERIMENTAL 1406 depends on KEXEC && HIBERNATION && X86_32 1407 help 1408 Jump between original kernel and kexeced kernel and invoke 1409 code in physical address mode via KEXEC 1410 1411config PHYSICAL_START 1412 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP) 1413 default "0x1000000" if X86_NUMAQ 1414 default "0x200000" if X86_64 1415 default "0x100000" 1416 help 1417 This gives the physical address where the kernel is loaded. 1418 1419 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 1420 bzImage will decompress itself to above physical address and 1421 run from there. Otherwise, bzImage will run from the address where 1422 it has been loaded by the boot loader and will ignore above physical 1423 address. 1424 1425 In normal kdump cases one does not have to set/change this option 1426 as now bzImage can be compiled as a completely relocatable image 1427 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 1428 address. This option is mainly useful for the folks who don't want 1429 to use a bzImage for capturing the crash dump and want to use a 1430 vmlinux instead. vmlinux is not relocatable hence a kernel needs 1431 to be specifically compiled to run from a specific memory area 1432 (normally a reserved region) and this option comes handy. 1433 1434 So if you are using bzImage for capturing the crash dump, leave 1435 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y. 1436 Otherwise if you plan to use vmlinux for capturing the crash dump 1437 change this value to start of the reserved region (Typically 16MB 1438 0x1000000). In other words, it can be set based on the "X" value as 1439 specified in the "crashkernel=YM@XM" command line boot parameter 1440 passed to the panic-ed kernel. Typically this parameter is set as 1441 crashkernel=64M@16M. Please take a look at 1442 Documentation/kdump/kdump.txt for more details about crash dumps. 1443 1444 Usage of bzImage for capturing the crash dump is recommended as 1445 one does not have to build two kernels. Same kernel can be used 1446 as production kernel and capture kernel. Above option should have 1447 gone away after relocatable bzImage support is introduced. But it 1448 is present because there are users out there who continue to use 1449 vmlinux for dump capture. This option should go away down the 1450 line. 1451 1452 Don't change this unless you know what you are doing. 1453 1454config RELOCATABLE 1455 bool "Build a relocatable kernel (EXPERIMENTAL)" 1456 depends on EXPERIMENTAL 1457 help 1458 This builds a kernel image that retains relocation information 1459 so it can be loaded someplace besides the default 1MB. 1460 The relocations tend to make the kernel binary about 10% larger, 1461 but are discarded at runtime. 1462 1463 One use is for the kexec on panic case where the recovery kernel 1464 must live at a different physical address than the primary 1465 kernel. 1466 1467 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 1468 it has been loaded at and the compile time physical address 1469 (CONFIG_PHYSICAL_START) is ignored. 1470 1471config PHYSICAL_ALIGN 1472 hex 1473 prompt "Alignment value to which kernel should be aligned" if X86_32 1474 default "0x100000" if X86_32 1475 default "0x200000" if X86_64 1476 range 0x2000 0x400000 1477 help 1478 This value puts the alignment restrictions on physical address 1479 where kernel is loaded and run from. Kernel is compiled for an 1480 address which meets above alignment restriction. 1481 1482 If bootloader loads the kernel at a non-aligned address and 1483 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 1484 address aligned to above value and run from there. 1485 1486 If bootloader loads the kernel at a non-aligned address and 1487 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 1488 load address and decompress itself to the address it has been 1489 compiled for and run from there. The address for which kernel is 1490 compiled already meets above alignment restrictions. Hence the 1491 end result is that kernel runs from a physical address meeting 1492 above alignment restrictions. 1493 1494 Don't change this unless you know what you are doing. 1495 1496config HOTPLUG_CPU 1497 bool "Support for hot-pluggable CPUs" 1498 depends on SMP && HOTPLUG && !X86_VOYAGER 1499 ---help--- 1500 Say Y here to allow turning CPUs off and on. CPUs can be 1501 controlled through /sys/devices/system/cpu. 1502 ( Note: power management support will enable this option 1503 automatically on SMP systems. ) 1504 Say N if you want to disable CPU hotplug. 1505 1506config COMPAT_VDSO 1507 def_bool y 1508 prompt "Compat VDSO support" 1509 depends on X86_32 || IA32_EMULATION 1510 help 1511 Map the 32-bit VDSO to the predictable old-style address too. 1512 ---help--- 1513 Say N here if you are running a sufficiently recent glibc 1514 version (2.3.3 or later), to remove the high-mapped 1515 VDSO mapping and to exclusively use the randomized VDSO. 1516 1517 If unsure, say Y. 1518 1519config CMDLINE_BOOL 1520 bool "Built-in kernel command line" 1521 default n 1522 help 1523 Allow for specifying boot arguments to the kernel at 1524 build time. On some systems (e.g. embedded ones), it is 1525 necessary or convenient to provide some or all of the 1526 kernel boot arguments with the kernel itself (that is, 1527 to not rely on the boot loader to provide them.) 1528 1529 To compile command line arguments into the kernel, 1530 set this option to 'Y', then fill in the 1531 the boot arguments in CONFIG_CMDLINE. 1532 1533 Systems with fully functional boot loaders (i.e. non-embedded) 1534 should leave this option set to 'N'. 1535 1536config CMDLINE 1537 string "Built-in kernel command string" 1538 depends on CMDLINE_BOOL 1539 default "" 1540 help 1541 Enter arguments here that should be compiled into the kernel 1542 image and used at boot time. If the boot loader provides a 1543 command line at boot time, it is appended to this string to 1544 form the full kernel command line, when the system boots. 1545 1546 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 1547 change this behavior. 1548 1549 In most cases, the command line (whether built-in or provided 1550 by the boot loader) should specify the device for the root 1551 file system. 1552 1553config CMDLINE_OVERRIDE 1554 bool "Built-in command line overrides boot loader arguments" 1555 default n 1556 depends on CMDLINE_BOOL 1557 help 1558 Set this option to 'Y' to have the kernel ignore the boot loader 1559 command line, and use ONLY the built-in command line. 1560 1561 This is used to work around broken boot loaders. This should 1562 be set to 'N' under normal conditions. 1563 1564endmenu 1565 1566config ARCH_ENABLE_MEMORY_HOTPLUG 1567 def_bool y 1568 depends on X86_64 || (X86_32 && HIGHMEM) 1569 1570config ARCH_ENABLE_MEMORY_HOTREMOVE 1571 def_bool y 1572 depends on MEMORY_HOTPLUG 1573 1574config HAVE_ARCH_EARLY_PFN_TO_NID 1575 def_bool X86_64 1576 depends on NUMA 1577 1578menu "Power management and ACPI options" 1579 depends on !X86_VOYAGER 1580 1581config ARCH_HIBERNATION_HEADER 1582 def_bool y 1583 depends on X86_64 && HIBERNATION 1584 1585source "kernel/power/Kconfig" 1586 1587source "drivers/acpi/Kconfig" 1588 1589config X86_APM_BOOT 1590 bool 1591 default y 1592 depends on APM || APM_MODULE 1593 1594menuconfig APM 1595 tristate "APM (Advanced Power Management) BIOS support" 1596 depends on X86_32 && PM_SLEEP 1597 ---help--- 1598 APM is a BIOS specification for saving power using several different 1599 techniques. This is mostly useful for battery powered laptops with 1600 APM compliant BIOSes. If you say Y here, the system time will be 1601 reset after a RESUME operation, the /proc/apm device will provide 1602 battery status information, and user-space programs will receive 1603 notification of APM "events" (e.g. battery status change). 1604 1605 If you select "Y" here, you can disable actual use of the APM 1606 BIOS by passing the "apm=off" option to the kernel at boot time. 1607 1608 Note that the APM support is almost completely disabled for 1609 machines with more than one CPU. 1610 1611 In order to use APM, you will need supporting software. For location 1612 and more information, read <file:Documentation/power/pm.txt> and the 1613 Battery Powered Linux mini-HOWTO, available from 1614 <http://www.tldp.org/docs.html#howto>. 1615 1616 This driver does not spin down disk drives (see the hdparm(8) 1617 manpage ("man 8 hdparm") for that), and it doesn't turn off 1618 VESA-compliant "green" monitors. 1619 1620 This driver does not support the TI 4000M TravelMate and the ACER 1621 486/DX4/75 because they don't have compliant BIOSes. Many "green" 1622 desktop machines also don't have compliant BIOSes, and this driver 1623 may cause those machines to panic during the boot phase. 1624 1625 Generally, if you don't have a battery in your machine, there isn't 1626 much point in using this driver and you should say N. If you get 1627 random kernel OOPSes or reboots that don't seem to be related to 1628 anything, try disabling/enabling this option (or disabling/enabling 1629 APM in your BIOS). 1630 1631 Some other things you should try when experiencing seemingly random, 1632 "weird" problems: 1633 1634 1) make sure that you have enough swap space and that it is 1635 enabled. 1636 2) pass the "no-hlt" option to the kernel 1637 3) switch on floating point emulation in the kernel and pass 1638 the "no387" option to the kernel 1639 4) pass the "floppy=nodma" option to the kernel 1640 5) pass the "mem=4M" option to the kernel (thereby disabling 1641 all but the first 4 MB of RAM) 1642 6) make sure that the CPU is not over clocked. 1643 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 1644 8) disable the cache from your BIOS settings 1645 9) install a fan for the video card or exchange video RAM 1646 10) install a better fan for the CPU 1647 11) exchange RAM chips 1648 12) exchange the motherboard. 1649 1650 To compile this driver as a module, choose M here: the 1651 module will be called apm. 1652 1653if APM 1654 1655config APM_IGNORE_USER_SUSPEND 1656 bool "Ignore USER SUSPEND" 1657 help 1658 This option will ignore USER SUSPEND requests. On machines with a 1659 compliant APM BIOS, you want to say N. However, on the NEC Versa M 1660 series notebooks, it is necessary to say Y because of a BIOS bug. 1661 1662config APM_DO_ENABLE 1663 bool "Enable PM at boot time" 1664 ---help--- 1665 Enable APM features at boot time. From page 36 of the APM BIOS 1666 specification: "When disabled, the APM BIOS does not automatically 1667 power manage devices, enter the Standby State, enter the Suspend 1668 State, or take power saving steps in response to CPU Idle calls." 1669 This driver will make CPU Idle calls when Linux is idle (unless this 1670 feature is turned off -- see "Do CPU IDLE calls", below). This 1671 should always save battery power, but more complicated APM features 1672 will be dependent on your BIOS implementation. You may need to turn 1673 this option off if your computer hangs at boot time when using APM 1674 support, or if it beeps continuously instead of suspending. Turn 1675 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 1676 T400CDT. This is off by default since most machines do fine without 1677 this feature. 1678 1679config APM_CPU_IDLE 1680 bool "Make CPU Idle calls when idle" 1681 help 1682 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 1683 On some machines, this can activate improved power savings, such as 1684 a slowed CPU clock rate, when the machine is idle. These idle calls 1685 are made after the idle loop has run for some length of time (e.g., 1686 333 mS). On some machines, this will cause a hang at boot time or 1687 whenever the CPU becomes idle. (On machines with more than one CPU, 1688 this option does nothing.) 1689 1690config APM_DISPLAY_BLANK 1691 bool "Enable console blanking using APM" 1692 help 1693 Enable console blanking using the APM. Some laptops can use this to 1694 turn off the LCD backlight when the screen blanker of the Linux 1695 virtual console blanks the screen. Note that this is only used by 1696 the virtual console screen blanker, and won't turn off the backlight 1697 when using the X Window system. This also doesn't have anything to 1698 do with your VESA-compliant power-saving monitor. Further, this 1699 option doesn't work for all laptops -- it might not turn off your 1700 backlight at all, or it might print a lot of errors to the console, 1701 especially if you are using gpm. 1702 1703config APM_ALLOW_INTS 1704 bool "Allow interrupts during APM BIOS calls" 1705 help 1706 Normally we disable external interrupts while we are making calls to 1707 the APM BIOS as a measure to lessen the effects of a badly behaving 1708 BIOS implementation. The BIOS should reenable interrupts if it 1709 needs to. Unfortunately, some BIOSes do not -- especially those in 1710 many of the newer IBM Thinkpads. If you experience hangs when you 1711 suspend, try setting this to Y. Otherwise, say N. 1712 1713endif # APM 1714 1715source "arch/x86/kernel/cpu/cpufreq/Kconfig" 1716 1717source "drivers/cpuidle/Kconfig" 1718 1719source "drivers/idle/Kconfig" 1720 1721endmenu 1722 1723 1724menu "Bus options (PCI etc.)" 1725 1726config PCI 1727 bool "PCI support" 1728 default y 1729 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC) 1730 help 1731 Find out whether you have a PCI motherboard. PCI is the name of a 1732 bus system, i.e. the way the CPU talks to the other stuff inside 1733 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 1734 VESA. If you have PCI, say Y, otherwise N. 1735 1736choice 1737 prompt "PCI access mode" 1738 depends on X86_32 && PCI 1739 default PCI_GOANY 1740 ---help--- 1741 On PCI systems, the BIOS can be used to detect the PCI devices and 1742 determine their configuration. However, some old PCI motherboards 1743 have BIOS bugs and may crash if this is done. Also, some embedded 1744 PCI-based systems don't have any BIOS at all. Linux can also try to 1745 detect the PCI hardware directly without using the BIOS. 1746 1747 With this option, you can specify how Linux should detect the 1748 PCI devices. If you choose "BIOS", the BIOS will be used, 1749 if you choose "Direct", the BIOS won't be used, and if you 1750 choose "MMConfig", then PCI Express MMCONFIG will be used. 1751 If you choose "Any", the kernel will try MMCONFIG, then the 1752 direct access method and falls back to the BIOS if that doesn't 1753 work. If unsure, go with the default, which is "Any". 1754 1755config PCI_GOBIOS 1756 bool "BIOS" 1757 1758config PCI_GOMMCONFIG 1759 bool "MMConfig" 1760 1761config PCI_GODIRECT 1762 bool "Direct" 1763 1764config PCI_GOOLPC 1765 bool "OLPC" 1766 depends on OLPC 1767 1768config PCI_GOANY 1769 bool "Any" 1770 1771endchoice 1772 1773config PCI_BIOS 1774 def_bool y 1775 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 1776 1777# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 1778config PCI_DIRECT 1779 def_bool y 1780 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC)) 1781 1782config PCI_MMCONFIG 1783 def_bool y 1784 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY) 1785 1786config PCI_OLPC 1787 def_bool y 1788 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 1789 1790config PCI_DOMAINS 1791 def_bool y 1792 depends on PCI 1793 1794config PCI_MMCONFIG 1795 bool "Support mmconfig PCI config space access" 1796 depends on X86_64 && PCI && ACPI 1797 1798config DMAR 1799 bool "Support for DMA Remapping Devices (EXPERIMENTAL)" 1800 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL 1801 help 1802 DMA remapping (DMAR) devices support enables independent address 1803 translations for Direct Memory Access (DMA) from devices. 1804 These DMA remapping devices are reported via ACPI tables 1805 and include PCI device scope covered by these DMA 1806 remapping devices. 1807 1808config DMAR_GFX_WA 1809 def_bool y 1810 prompt "Support for Graphics workaround" 1811 depends on DMAR 1812 help 1813 Current Graphics drivers tend to use physical address 1814 for DMA and avoid using DMA APIs. Setting this config 1815 option permits the IOMMU driver to set a unity map for 1816 all the OS-visible memory. Hence the driver can continue 1817 to use physical addresses for DMA. 1818 1819config DMAR_FLOPPY_WA 1820 def_bool y 1821 depends on DMAR 1822 help 1823 Floppy disk drivers are know to bypass DMA API calls 1824 thereby failing to work when IOMMU is enabled. This 1825 workaround will setup a 1:1 mapping for the first 1826 16M to make floppy (an ISA device) work. 1827 1828config INTR_REMAP 1829 bool "Support for Interrupt Remapping (EXPERIMENTAL)" 1830 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL 1831 help 1832 Supports Interrupt remapping for IO-APIC and MSI devices. 1833 To use x2apic mode in the CPU's which support x2APIC enhancements or 1834 to support platforms with CPU's having > 8 bit APIC ID, say Y. 1835 1836source "drivers/pci/pcie/Kconfig" 1837 1838source "drivers/pci/Kconfig" 1839 1840# x86_64 have no ISA slots, but do have ISA-style DMA. 1841config ISA_DMA_API 1842 def_bool y 1843 1844if X86_32 1845 1846config ISA 1847 bool "ISA support" 1848 depends on !X86_VOYAGER 1849 help 1850 Find out whether you have ISA slots on your motherboard. ISA is the 1851 name of a bus system, i.e. the way the CPU talks to the other stuff 1852 inside your box. Other bus systems are PCI, EISA, MicroChannel 1853 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 1854 newer boards don't support it. If you have ISA, say Y, otherwise N. 1855 1856config EISA 1857 bool "EISA support" 1858 depends on ISA 1859 ---help--- 1860 The Extended Industry Standard Architecture (EISA) bus was 1861 developed as an open alternative to the IBM MicroChannel bus. 1862 1863 The EISA bus provided some of the features of the IBM MicroChannel 1864 bus while maintaining backward compatibility with cards made for 1865 the older ISA bus. The EISA bus saw limited use between 1988 and 1866 1995 when it was made obsolete by the PCI bus. 1867 1868 Say Y here if you are building a kernel for an EISA-based machine. 1869 1870 Otherwise, say N. 1871 1872source "drivers/eisa/Kconfig" 1873 1874config MCA 1875 bool "MCA support" 1876 help 1877 MicroChannel Architecture is found in some IBM PS/2 machines and 1878 laptops. It is a bus system similar to PCI or ISA. See 1879 <file:Documentation/mca.txt> (and especially the web page given 1880 there) before attempting to build an MCA bus kernel. 1881 1882source "drivers/mca/Kconfig" 1883 1884config SCx200 1885 tristate "NatSemi SCx200 support" 1886 help 1887 This provides basic support for National Semiconductor's 1888 (now AMD's) Geode processors. The driver probes for the 1889 PCI-IDs of several on-chip devices, so its a good dependency 1890 for other scx200_* drivers. 1891 1892 If compiled as a module, the driver is named scx200. 1893 1894config SCx200HR_TIMER 1895 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 1896 depends on SCx200 && GENERIC_TIME 1897 default y 1898 help 1899 This driver provides a clocksource built upon the on-chip 1900 27MHz high-resolution timer. Its also a workaround for 1901 NSC Geode SC-1100's buggy TSC, which loses time when the 1902 processor goes idle (as is done by the scheduler). The 1903 other workaround is idle=poll boot option. 1904 1905config GEODE_MFGPT_TIMER 1906 def_bool y 1907 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events" 1908 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS 1909 help 1910 This driver provides a clock event source based on the MFGPT 1911 timer(s) in the CS5535 and CS5536 companion chip for the geode. 1912 MFGPTs have a better resolution and max interval than the 1913 generic PIT, and are suitable for use as high-res timers. 1914 1915config OLPC 1916 bool "One Laptop Per Child support" 1917 default n 1918 help 1919 Add support for detecting the unique features of the OLPC 1920 XO hardware. 1921 1922endif # X86_32 1923 1924config K8_NB 1925 def_bool y 1926 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA))) 1927 1928source "drivers/pcmcia/Kconfig" 1929 1930source "drivers/pci/hotplug/Kconfig" 1931 1932endmenu 1933 1934 1935menu "Executable file formats / Emulations" 1936 1937source "fs/Kconfig.binfmt" 1938 1939config IA32_EMULATION 1940 bool "IA32 Emulation" 1941 depends on X86_64 1942 select COMPAT_BINFMT_ELF 1943 help 1944 Include code to run 32-bit programs under a 64-bit kernel. You should 1945 likely turn this on, unless you're 100% sure that you don't have any 1946 32-bit programs left. 1947 1948config IA32_AOUT 1949 tristate "IA32 a.out support" 1950 depends on IA32_EMULATION 1951 help 1952 Support old a.out binaries in the 32bit emulation. 1953 1954config COMPAT 1955 def_bool y 1956 depends on IA32_EMULATION 1957 1958config COMPAT_FOR_U64_ALIGNMENT 1959 def_bool COMPAT 1960 depends on X86_64 1961 1962config SYSVIPC_COMPAT 1963 def_bool y 1964 depends on COMPAT && SYSVIPC 1965 1966endmenu 1967 1968 1969config HAVE_ATOMIC_IOMAP 1970 def_bool y 1971 depends on X86_32 1972 1973source "net/Kconfig" 1974 1975source "drivers/Kconfig" 1976 1977source "drivers/firmware/Kconfig" 1978 1979source "fs/Kconfig" 1980 1981source "arch/x86/Kconfig.debug" 1982 1983source "security/Kconfig" 1984 1985source "crypto/Kconfig" 1986 1987source "arch/x86/kvm/Kconfig" 1988 1989source "lib/Kconfig" 1990