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