Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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1# 2# For a description of the syntax of this configuration file, 3# see Documentation/kbuild/kconfig-language.txt. 4# 5 6mainmenu "Linux Kernel Configuration" 7 8config X86_32 9 bool 10 default y 11 help 12 This is Linux's home port. Linux was originally native to the Intel 13 386, and runs on all the later x86 processors including the Intel 14 486, 586, Pentiums, and various instruction-set-compatible chips by 15 AMD, Cyrix, and others. 16 17config GENERIC_TIME 18 bool 19 default y 20 21config CLOCKSOURCE_WATCHDOG 22 bool 23 default y 24 25config GENERIC_CLOCKEVENTS 26 bool 27 default y 28 29config GENERIC_CLOCKEVENTS_BROADCAST 30 bool 31 default y 32 depends on X86_LOCAL_APIC 33 34config LOCKDEP_SUPPORT 35 bool 36 default y 37 38config STACKTRACE_SUPPORT 39 bool 40 default y 41 42config SEMAPHORE_SLEEPERS 43 bool 44 default y 45 46config X86 47 bool 48 default y 49 50config MMU 51 bool 52 default y 53 54config ZONE_DMA 55 bool 56 default y 57 58config SBUS 59 bool 60 61config GENERIC_ISA_DMA 62 bool 63 default y 64 65config GENERIC_IOMAP 66 bool 67 default y 68 69config GENERIC_BUG 70 bool 71 default y 72 depends on BUG 73 74config GENERIC_HWEIGHT 75 bool 76 default y 77 78config ARCH_MAY_HAVE_PC_FDC 79 bool 80 default y 81 82config DMI 83 bool 84 default y 85 86source "init/Kconfig" 87 88menu "Processor type and features" 89 90source "kernel/time/Kconfig" 91 92config SMP 93 bool "Symmetric multi-processing support" 94 ---help--- 95 This enables support for systems with more than one CPU. If you have 96 a system with only one CPU, like most personal computers, say N. If 97 you have a system with more than one CPU, say Y. 98 99 If you say N here, the kernel will run on single and multiprocessor 100 machines, but will use only one CPU of a multiprocessor machine. If 101 you say Y here, the kernel will run on many, but not all, 102 singleprocessor machines. On a singleprocessor machine, the kernel 103 will run faster if you say N here. 104 105 Note that if you say Y here and choose architecture "586" or 106 "Pentium" under "Processor family", the kernel will not work on 486 107 architectures. Similarly, multiprocessor kernels for the "PPro" 108 architecture may not work on all Pentium based boards. 109 110 People using multiprocessor machines who say Y here should also say 111 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 112 Management" code will be disabled if you say Y here. 113 114 See also the <file:Documentation/smp.txt>, 115 <file:Documentation/i386/IO-APIC.txt>, 116 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at 117 <http://www.tldp.org/docs.html#howto>. 118 119 If you don't know what to do here, say N. 120 121choice 122 prompt "Subarchitecture Type" 123 default X86_PC 124 125config X86_PC 126 bool "PC-compatible" 127 help 128 Choose this option if your computer is a standard PC or compatible. 129 130config X86_ELAN 131 bool "AMD Elan" 132 help 133 Select this for an AMD Elan processor. 134 135 Do not use this option for K6/Athlon/Opteron processors! 136 137 If unsure, choose "PC-compatible" instead. 138 139config X86_VOYAGER 140 bool "Voyager (NCR)" 141 help 142 Voyager is an MCA-based 32-way capable SMP architecture proprietary 143 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based. 144 145 *** WARNING *** 146 147 If you do not specifically know you have a Voyager based machine, 148 say N here, otherwise the kernel you build will not be bootable. 149 150config X86_NUMAQ 151 bool "NUMAQ (IBM/Sequent)" 152 select SMP 153 select NUMA 154 help 155 This option is used for getting Linux to run on a (IBM/Sequent) NUMA 156 multiquad box. This changes the way that processors are bootstrapped, 157 and uses Clustered Logical APIC addressing mode instead of Flat Logical. 158 You will need a new lynxer.elf file to flash your firmware with - send 159 email to <Martin.Bligh@us.ibm.com>. 160 161config X86_SUMMIT 162 bool "Summit/EXA (IBM x440)" 163 depends on SMP 164 help 165 This option is needed for IBM systems that use the Summit/EXA chipset. 166 In particular, it is needed for the x440. 167 168 If you don't have one of these computers, you should say N here. 169 If you want to build a NUMA kernel, you must select ACPI. 170 171config X86_BIGSMP 172 bool "Support for other sub-arch SMP systems with more than 8 CPUs" 173 depends on SMP 174 help 175 This option is needed for the systems that have more than 8 CPUs 176 and if the system is not of any sub-arch type above. 177 178 If you don't have such a system, you should say N here. 179 180config X86_VISWS 181 bool "SGI 320/540 (Visual Workstation)" 182 help 183 The SGI Visual Workstation series is an IA32-based workstation 184 based on SGI systems chips with some legacy PC hardware attached. 185 186 Say Y here to create a kernel to run on the SGI 320 or 540. 187 188 A kernel compiled for the Visual Workstation will not run on PCs 189 and vice versa. See <file:Documentation/sgi-visws.txt> for details. 190 191config X86_GENERICARCH 192 bool "Generic architecture (Summit, bigsmp, ES7000, default)" 193 help 194 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures. 195 It is intended for a generic binary kernel. 196 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA. 197 198config X86_ES7000 199 bool "Support for Unisys ES7000 IA32 series" 200 depends on SMP 201 help 202 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is 203 supposed to run on an IA32-based Unisys ES7000 system. 204 Only choose this option if you have such a system, otherwise you 205 should say N here. 206 207endchoice 208 209config PARAVIRT 210 bool "Paravirtualization support (EXPERIMENTAL)" 211 depends on EXPERIMENTAL 212 depends on !(X86_VISWS || X86_VOYAGER) 213 help 214 Paravirtualization is a way of running multiple instances of 215 Linux on the same machine, under a hypervisor. This option 216 changes the kernel so it can modify itself when it is run 217 under a hypervisor, improving performance significantly. 218 However, when run without a hypervisor the kernel is 219 theoretically slower. If in doubt, say N. 220 221config VMI 222 bool "VMI Paravirt-ops support" 223 depends on PARAVIRT && !COMPAT_VDSO 224 help 225 VMI provides a paravirtualized interface to the VMware ESX server 226 (it could be used by other hypervisors in theory too, but is not 227 at the moment), by linking the kernel to a GPL-ed ROM module 228 provided by the hypervisor. 229 230config ACPI_SRAT 231 bool 232 default y 233 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH) 234 select ACPI_NUMA 235 236config HAVE_ARCH_PARSE_SRAT 237 bool 238 default y 239 depends on ACPI_SRAT 240 241config X86_SUMMIT_NUMA 242 bool 243 default y 244 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH) 245 246config X86_CYCLONE_TIMER 247 bool 248 default y 249 depends on X86_SUMMIT || X86_GENERICARCH 250 251config ES7000_CLUSTERED_APIC 252 bool 253 default y 254 depends on SMP && X86_ES7000 && MPENTIUMIII 255 256source "arch/i386/Kconfig.cpu" 257 258config HPET_TIMER 259 bool "HPET Timer Support" 260 help 261 This enables the use of the HPET for the kernel's internal timer. 262 HPET is the next generation timer replacing legacy 8254s. 263 You can safely choose Y here. However, HPET will only be 264 activated if the platform and the BIOS support this feature. 265 Otherwise the 8254 will be used for timing services. 266 267 Choose N to continue using the legacy 8254 timer. 268 269config HPET_EMULATE_RTC 270 bool 271 depends on HPET_TIMER && RTC=y 272 default y 273 274config NR_CPUS 275 int "Maximum number of CPUs (2-255)" 276 range 2 255 277 depends on SMP 278 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000 279 default "8" 280 help 281 This allows you to specify the maximum number of CPUs which this 282 kernel will support. The maximum supported value is 255 and the 283 minimum value which makes sense is 2. 284 285 This is purely to save memory - each supported CPU adds 286 approximately eight kilobytes to the kernel image. 287 288config SCHED_SMT 289 bool "SMT (Hyperthreading) scheduler support" 290 depends on X86_HT 291 help 292 SMT scheduler support improves the CPU scheduler's decision making 293 when dealing with Intel Pentium 4 chips with HyperThreading at a 294 cost of slightly increased overhead in some places. If unsure say 295 N here. 296 297config SCHED_MC 298 bool "Multi-core scheduler support" 299 depends on X86_HT 300 default y 301 help 302 Multi-core scheduler support improves the CPU scheduler's decision 303 making when dealing with multi-core CPU chips at a cost of slightly 304 increased overhead in some places. If unsure say N here. 305 306source "kernel/Kconfig.preempt" 307 308config X86_UP_APIC 309 bool "Local APIC support on uniprocessors" 310 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH) 311 help 312 A local APIC (Advanced Programmable Interrupt Controller) is an 313 integrated interrupt controller in the CPU. If you have a single-CPU 314 system which has a processor with a local APIC, you can say Y here to 315 enable and use it. If you say Y here even though your machine doesn't 316 have a local APIC, then the kernel will still run with no slowdown at 317 all. The local APIC supports CPU-generated self-interrupts (timer, 318 performance counters), and the NMI watchdog which detects hard 319 lockups. 320 321config X86_UP_IOAPIC 322 bool "IO-APIC support on uniprocessors" 323 depends on X86_UP_APIC 324 help 325 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 326 SMP-capable replacement for PC-style interrupt controllers. Most 327 SMP systems and many recent uniprocessor systems have one. 328 329 If you have a single-CPU system with an IO-APIC, you can say Y here 330 to use it. If you say Y here even though your machine doesn't have 331 an IO-APIC, then the kernel will still run with no slowdown at all. 332 333config X86_LOCAL_APIC 334 bool 335 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH 336 default y 337 338config X86_IO_APIC 339 bool 340 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH 341 default y 342 343config X86_VISWS_APIC 344 bool 345 depends on X86_VISWS 346 default y 347 348config X86_MCE 349 bool "Machine Check Exception" 350 depends on !X86_VOYAGER 351 ---help--- 352 Machine Check Exception support allows the processor to notify the 353 kernel if it detects a problem (e.g. overheating, component failure). 354 The action the kernel takes depends on the severity of the problem, 355 ranging from a warning message on the console, to halting the machine. 356 Your processor must be a Pentium or newer to support this - check the 357 flags in /proc/cpuinfo for mce. Note that some older Pentium systems 358 have a design flaw which leads to false MCE events - hence MCE is 359 disabled on all P5 processors, unless explicitly enabled with "mce" 360 as a boot argument. Similarly, if MCE is built in and creates a 361 problem on some new non-standard machine, you can boot with "nomce" 362 to disable it. MCE support simply ignores non-MCE processors like 363 the 386 and 486, so nearly everyone can say Y here. 364 365config X86_MCE_NONFATAL 366 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4" 367 depends on X86_MCE 368 help 369 Enabling this feature starts a timer that triggers every 5 seconds which 370 will look at the machine check registers to see if anything happened. 371 Non-fatal problems automatically get corrected (but still logged). 372 Disable this if you don't want to see these messages. 373 Seeing the messages this option prints out may be indicative of dying hardware, 374 or out-of-spec (ie, overclocked) hardware. 375 This option only does something on certain CPUs. 376 (AMD Athlon/Duron and Intel Pentium 4) 377 378config X86_MCE_P4THERMAL 379 bool "check for P4 thermal throttling interrupt." 380 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS 381 help 382 Enabling this feature will cause a message to be printed when the P4 383 enters thermal throttling. 384 385config VM86 386 default y 387 bool "Enable VM86 support" if EMBEDDED 388 help 389 This option is required by programs like DOSEMU to run 16-bit legacy 390 code on X86 processors. It also may be needed by software like 391 XFree86 to initialize some video cards via BIOS. Disabling this 392 option saves about 6k. 393 394config TOSHIBA 395 tristate "Toshiba Laptop support" 396 ---help--- 397 This adds a driver to safely access the System Management Mode of 398 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 399 not work on models with a Phoenix BIOS. The System Management Mode 400 is used to set the BIOS and power saving options on Toshiba portables. 401 402 For information on utilities to make use of this driver see the 403 Toshiba Linux utilities web site at: 404 <http://www.buzzard.org.uk/toshiba/>. 405 406 Say Y if you intend to run this kernel on a Toshiba portable. 407 Say N otherwise. 408 409config I8K 410 tristate "Dell laptop support" 411 ---help--- 412 This adds a driver to safely access the System Management Mode 413 of the CPU on the Dell Inspiron 8000. The System Management Mode 414 is used to read cpu temperature and cooling fan status and to 415 control the fans on the I8K portables. 416 417 This driver has been tested only on the Inspiron 8000 but it may 418 also work with other Dell laptops. You can force loading on other 419 models by passing the parameter `force=1' to the module. Use at 420 your own risk. 421 422 For information on utilities to make use of this driver see the 423 I8K Linux utilities web site at: 424 <http://people.debian.org/~dz/i8k/> 425 426 Say Y if you intend to run this kernel on a Dell Inspiron 8000. 427 Say N otherwise. 428 429config X86_REBOOTFIXUPS 430 bool "Enable X86 board specific fixups for reboot" 431 depends on X86 432 default n 433 ---help--- 434 This enables chipset and/or board specific fixups to be done 435 in order to get reboot to work correctly. This is only needed on 436 some combinations of hardware and BIOS. The symptom, for which 437 this config is intended, is when reboot ends with a stalled/hung 438 system. 439 440 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1. 441 combination. 442 443 Say Y if you want to enable the fixup. Currently, it's safe to 444 enable this option even if you don't need it. 445 Say N otherwise. 446 447config MICROCODE 448 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support" 449 select FW_LOADER 450 ---help--- 451 If you say Y here and also to "/dev file system support" in the 452 'File systems' section, you will be able to update the microcode on 453 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II, 454 Pentium III, Pentium 4, Xeon etc. You will obviously need the 455 actual microcode binary data itself which is not shipped with the 456 Linux kernel. 457 458 For latest news and information on obtaining all the required 459 ingredients for this driver, check: 460 <http://www.urbanmyth.org/microcode/>. 461 462 To compile this driver as a module, choose M here: the 463 module will be called microcode. 464 465config MICROCODE_OLD_INTERFACE 466 bool 467 depends on MICROCODE 468 default y 469 470config X86_MSR 471 tristate "/dev/cpu/*/msr - Model-specific register support" 472 help 473 This device gives privileged processes access to the x86 474 Model-Specific Registers (MSRs). It is a character device with 475 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 476 MSR accesses are directed to a specific CPU on multi-processor 477 systems. 478 479config X86_CPUID 480 tristate "/dev/cpu/*/cpuid - CPU information support" 481 help 482 This device gives processes access to the x86 CPUID instruction to 483 be executed on a specific processor. It is a character device 484 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 485 /dev/cpu/31/cpuid. 486 487source "drivers/firmware/Kconfig" 488 489choice 490 prompt "High Memory Support" 491 default HIGHMEM4G if !X86_NUMAQ 492 default HIGHMEM64G if X86_NUMAQ 493 494config NOHIGHMEM 495 bool "off" 496 depends on !X86_NUMAQ 497 ---help--- 498 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 499 However, the address space of 32-bit x86 processors is only 4 500 Gigabytes large. That means that, if you have a large amount of 501 physical memory, not all of it can be "permanently mapped" by the 502 kernel. The physical memory that's not permanently mapped is called 503 "high memory". 504 505 If you are compiling a kernel which will never run on a machine with 506 more than 1 Gigabyte total physical RAM, answer "off" here (default 507 choice and suitable for most users). This will result in a "3GB/1GB" 508 split: 3GB are mapped so that each process sees a 3GB virtual memory 509 space and the remaining part of the 4GB virtual memory space is used 510 by the kernel to permanently map as much physical memory as 511 possible. 512 513 If the machine has between 1 and 4 Gigabytes physical RAM, then 514 answer "4GB" here. 515 516 If more than 4 Gigabytes is used then answer "64GB" here. This 517 selection turns Intel PAE (Physical Address Extension) mode on. 518 PAE implements 3-level paging on IA32 processors. PAE is fully 519 supported by Linux, PAE mode is implemented on all recent Intel 520 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 521 then the kernel will not boot on CPUs that don't support PAE! 522 523 The actual amount of total physical memory will either be 524 auto detected or can be forced by using a kernel command line option 525 such as "mem=256M". (Try "man bootparam" or see the documentation of 526 your boot loader (lilo or loadlin) about how to pass options to the 527 kernel at boot time.) 528 529 If unsure, say "off". 530 531config HIGHMEM4G 532 bool "4GB" 533 depends on !X86_NUMAQ 534 help 535 Select this if you have a 32-bit processor and between 1 and 4 536 gigabytes of physical RAM. 537 538config HIGHMEM64G 539 bool "64GB" 540 depends on X86_CMPXCHG64 541 help 542 Select this if you have a 32-bit processor and more than 4 543 gigabytes of physical RAM. 544 545endchoice 546 547choice 548 depends on EXPERIMENTAL 549 prompt "Memory split" if EMBEDDED 550 default VMSPLIT_3G 551 help 552 Select the desired split between kernel and user memory. 553 554 If the address range available to the kernel is less than the 555 physical memory installed, the remaining memory will be available 556 as "high memory". Accessing high memory is a little more costly 557 than low memory, as it needs to be mapped into the kernel first. 558 Note that increasing the kernel address space limits the range 559 available to user programs, making the address space there 560 tighter. Selecting anything other than the default 3G/1G split 561 will also likely make your kernel incompatible with binary-only 562 kernel modules. 563 564 If you are not absolutely sure what you are doing, leave this 565 option alone! 566 567 config VMSPLIT_3G 568 bool "3G/1G user/kernel split" 569 config VMSPLIT_3G_OPT 570 depends on !HIGHMEM 571 bool "3G/1G user/kernel split (for full 1G low memory)" 572 config VMSPLIT_2G 573 bool "2G/2G user/kernel split" 574 config VMSPLIT_1G 575 bool "1G/3G user/kernel split" 576endchoice 577 578config PAGE_OFFSET 579 hex 580 default 0xB0000000 if VMSPLIT_3G_OPT 581 default 0x78000000 if VMSPLIT_2G 582 default 0x40000000 if VMSPLIT_1G 583 default 0xC0000000 584 585config HIGHMEM 586 bool 587 depends on HIGHMEM64G || HIGHMEM4G 588 default y 589 590config X86_PAE 591 bool 592 depends on HIGHMEM64G 593 default y 594 select RESOURCES_64BIT 595 596# Common NUMA Features 597config NUMA 598 bool "Numa Memory Allocation and Scheduler Support" 599 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) 600 default n if X86_PC 601 default y if (X86_NUMAQ || X86_SUMMIT) 602 603comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI" 604 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI) 605 606config NODES_SHIFT 607 int 608 default "4" if X86_NUMAQ 609 default "3" 610 depends on NEED_MULTIPLE_NODES 611 612config HAVE_ARCH_BOOTMEM_NODE 613 bool 614 depends on NUMA 615 default y 616 617config ARCH_HAVE_MEMORY_PRESENT 618 bool 619 depends on DISCONTIGMEM 620 default y 621 622config NEED_NODE_MEMMAP_SIZE 623 bool 624 depends on DISCONTIGMEM || SPARSEMEM 625 default y 626 627config HAVE_ARCH_ALLOC_REMAP 628 bool 629 depends on NUMA 630 default y 631 632config ARCH_FLATMEM_ENABLE 633 def_bool y 634 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC) 635 636config ARCH_DISCONTIGMEM_ENABLE 637 def_bool y 638 depends on NUMA 639 640config ARCH_DISCONTIGMEM_DEFAULT 641 def_bool y 642 depends on NUMA 643 644config ARCH_SPARSEMEM_ENABLE 645 def_bool y 646 depends on (NUMA || (X86_PC && EXPERIMENTAL)) 647 select SPARSEMEM_STATIC 648 649config ARCH_SELECT_MEMORY_MODEL 650 def_bool y 651 depends on ARCH_SPARSEMEM_ENABLE 652 653config ARCH_POPULATES_NODE_MAP 654 def_bool y 655 656source "mm/Kconfig" 657 658config HIGHPTE 659 bool "Allocate 3rd-level pagetables from highmem" 660 depends on HIGHMEM4G || HIGHMEM64G 661 help 662 The VM uses one page table entry for each page of physical memory. 663 For systems with a lot of RAM, this can be wasteful of precious 664 low memory. Setting this option will put user-space page table 665 entries in high memory. 666 667config MATH_EMULATION 668 bool "Math emulation" 669 ---help--- 670 Linux can emulate a math coprocessor (used for floating point 671 operations) if you don't have one. 486DX and Pentium processors have 672 a math coprocessor built in, 486SX and 386 do not, unless you added 673 a 487DX or 387, respectively. (The messages during boot time can 674 give you some hints here ["man dmesg"].) Everyone needs either a 675 coprocessor or this emulation. 676 677 If you don't have a math coprocessor, you need to say Y here; if you 678 say Y here even though you have a coprocessor, the coprocessor will 679 be used nevertheless. (This behavior can be changed with the kernel 680 command line option "no387", which comes handy if your coprocessor 681 is broken. Try "man bootparam" or see the documentation of your boot 682 loader (lilo or loadlin) about how to pass options to the kernel at 683 boot time.) This means that it is a good idea to say Y here if you 684 intend to use this kernel on different machines. 685 686 More information about the internals of the Linux math coprocessor 687 emulation can be found in <file:arch/i386/math-emu/README>. 688 689 If you are not sure, say Y; apart from resulting in a 66 KB bigger 690 kernel, it won't hurt. 691 692config MTRR 693 bool "MTRR (Memory Type Range Register) support" 694 ---help--- 695 On Intel P6 family processors (Pentium Pro, Pentium II and later) 696 the Memory Type Range Registers (MTRRs) may be used to control 697 processor access to memory ranges. This is most useful if you have 698 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 699 allows bus write transfers to be combined into a larger transfer 700 before bursting over the PCI/AGP bus. This can increase performance 701 of image write operations 2.5 times or more. Saying Y here creates a 702 /proc/mtrr file which may be used to manipulate your processor's 703 MTRRs. Typically the X server should use this. 704 705 This code has a reasonably generic interface so that similar 706 control registers on other processors can be easily supported 707 as well: 708 709 The Cyrix 6x86, 6x86MX and M II processors have Address Range 710 Registers (ARRs) which provide a similar functionality to MTRRs. For 711 these, the ARRs are used to emulate the MTRRs. 712 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 713 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 714 write-combining. All of these processors are supported by this code 715 and it makes sense to say Y here if you have one of them. 716 717 Saying Y here also fixes a problem with buggy SMP BIOSes which only 718 set the MTRRs for the boot CPU and not for the secondary CPUs. This 719 can lead to all sorts of problems, so it's good to say Y here. 720 721 You can safely say Y even if your machine doesn't have MTRRs, you'll 722 just add about 9 KB to your kernel. 723 724 See <file:Documentation/mtrr.txt> for more information. 725 726config EFI 727 bool "Boot from EFI support" 728 depends on ACPI 729 default n 730 ---help--- 731 This enables the kernel to boot on EFI platforms using 732 system configuration information passed to it from the firmware. 733 This also enables the kernel to use any EFI runtime services that are 734 available (such as the EFI variable services). 735 736 This option is only useful on systems that have EFI firmware 737 and will result in a kernel image that is ~8k larger. In addition, 738 you must use the latest ELILO loader available at 739 <http://elilo.sourceforge.net> in order to take advantage of 740 kernel initialization using EFI information (neither GRUB nor LILO know 741 anything about EFI). However, even with this option, the resultant 742 kernel should continue to boot on existing non-EFI platforms. 743 744config IRQBALANCE 745 bool "Enable kernel irq balancing" 746 depends on SMP && X86_IO_APIC 747 default y 748 help 749 The default yes will allow the kernel to do irq load balancing. 750 Saying no will keep the kernel from doing irq load balancing. 751 752# turning this on wastes a bunch of space. 753# Summit needs it only when NUMA is on 754config BOOT_IOREMAP 755 bool 756 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI)) 757 default y 758 759config SECCOMP 760 bool "Enable seccomp to safely compute untrusted bytecode" 761 depends on PROC_FS 762 default y 763 help 764 This kernel feature is useful for number crunching applications 765 that may need to compute untrusted bytecode during their 766 execution. By using pipes or other transports made available to 767 the process as file descriptors supporting the read/write 768 syscalls, it's possible to isolate those applications in 769 their own address space using seccomp. Once seccomp is 770 enabled via /proc/<pid>/seccomp, it cannot be disabled 771 and the task is only allowed to execute a few safe syscalls 772 defined by each seccomp mode. 773 774 If unsure, say Y. Only embedded should say N here. 775 776source kernel/Kconfig.hz 777 778config KEXEC 779 bool "kexec system call" 780 help 781 kexec is a system call that implements the ability to shutdown your 782 current kernel, and to start another kernel. It is like a reboot 783 but it is independent of the system firmware. And like a reboot 784 you can start any kernel with it, not just Linux. 785 786 The name comes from the similarity to the exec system call. 787 788 It is an ongoing process to be certain the hardware in a machine 789 is properly shutdown, so do not be surprised if this code does not 790 initially work for you. It may help to enable device hotplugging 791 support. As of this writing the exact hardware interface is 792 strongly in flux, so no good recommendation can be made. 793 794config CRASH_DUMP 795 bool "kernel crash dumps (EXPERIMENTAL)" 796 depends on EXPERIMENTAL 797 depends on HIGHMEM 798 help 799 Generate crash dump after being started by kexec. 800 This should be normally only set in special crash dump kernels 801 which are loaded in the main kernel with kexec-tools into 802 a specially reserved region and then later executed after 803 a crash by kdump/kexec. The crash dump kernel must be compiled 804 to a memory address not used by the main kernel or BIOS using 805 PHYSICAL_START. 806 For more details see Documentation/kdump/kdump.txt 807 808config PHYSICAL_START 809 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP) 810 default "0x100000" 811 help 812 This gives the physical address where the kernel is loaded. 813 814 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 815 bzImage will decompress itself to above physical address and 816 run from there. Otherwise, bzImage will run from the address where 817 it has been loaded by the boot loader and will ignore above physical 818 address. 819 820 In normal kdump cases one does not have to set/change this option 821 as now bzImage can be compiled as a completely relocatable image 822 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 823 address. This option is mainly useful for the folks who don't want 824 to use a bzImage for capturing the crash dump and want to use a 825 vmlinux instead. vmlinux is not relocatable hence a kernel needs 826 to be specifically compiled to run from a specific memory area 827 (normally a reserved region) and this option comes handy. 828 829 So if you are using bzImage for capturing the crash dump, leave 830 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y. 831 Otherwise if you plan to use vmlinux for capturing the crash dump 832 change this value to start of the reserved region (Typically 16MB 833 0x1000000). In other words, it can be set based on the "X" value as 834 specified in the "crashkernel=YM@XM" command line boot parameter 835 passed to the panic-ed kernel. Typically this parameter is set as 836 crashkernel=64M@16M. Please take a look at 837 Documentation/kdump/kdump.txt for more details about crash dumps. 838 839 Usage of bzImage for capturing the crash dump is recommended as 840 one does not have to build two kernels. Same kernel can be used 841 as production kernel and capture kernel. Above option should have 842 gone away after relocatable bzImage support is introduced. But it 843 is present because there are users out there who continue to use 844 vmlinux for dump capture. This option should go away down the 845 line. 846 847 Don't change this unless you know what you are doing. 848 849config RELOCATABLE 850 bool "Build a relocatable kernel(EXPERIMENTAL)" 851 depends on EXPERIMENTAL 852 help 853 This build a kernel image that retains relocation information 854 so it can be loaded someplace besides the default 1MB. 855 The relocations tend to the kernel binary about 10% larger, 856 but are discarded at runtime. 857 858 One use is for the kexec on panic case where the recovery kernel 859 must live at a different physical address than the primary 860 kernel. 861 862config PHYSICAL_ALIGN 863 hex "Alignment value to which kernel should be aligned" 864 default "0x100000" 865 range 0x2000 0x400000 866 help 867 This value puts the alignment restrictions on physical address 868 where kernel is loaded and run from. Kernel is compiled for an 869 address which meets above alignment restriction. 870 871 If bootloader loads the kernel at a non-aligned address and 872 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 873 address aligned to above value and run from there. 874 875 If bootloader loads the kernel at a non-aligned address and 876 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 877 load address and decompress itself to the address it has been 878 compiled for and run from there. The address for which kernel is 879 compiled already meets above alignment restrictions. Hence the 880 end result is that kernel runs from a physical address meeting 881 above alignment restrictions. 882 883 Don't change this unless you know what you are doing. 884 885config HOTPLUG_CPU 886 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)" 887 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER 888 ---help--- 889 Say Y here to experiment with turning CPUs off and on, and to 890 enable suspend on SMP systems. CPUs can be controlled through 891 /sys/devices/system/cpu. 892 893config COMPAT_VDSO 894 bool "Compat VDSO support" 895 default y 896 help 897 Map the VDSO to the predictable old-style address too. 898 ---help--- 899 Say N here if you are running a sufficiently recent glibc 900 version (2.3.3 or later), to remove the high-mapped 901 VDSO mapping and to exclusively use the randomized VDSO. 902 903 If unsure, say Y. 904 905endmenu 906 907config ARCH_ENABLE_MEMORY_HOTPLUG 908 def_bool y 909 depends on HIGHMEM 910 911menu "Power management options (ACPI, APM)" 912 depends on !X86_VOYAGER 913 914source kernel/power/Kconfig 915 916source "drivers/acpi/Kconfig" 917 918menu "APM (Advanced Power Management) BIOS Support" 919depends on PM && !X86_VISWS 920 921config APM 922 tristate "APM (Advanced Power Management) BIOS support" 923 depends on PM 924 ---help--- 925 APM is a BIOS specification for saving power using several different 926 techniques. This is mostly useful for battery powered laptops with 927 APM compliant BIOSes. If you say Y here, the system time will be 928 reset after a RESUME operation, the /proc/apm device will provide 929 battery status information, and user-space programs will receive 930 notification of APM "events" (e.g. battery status change). 931 932 If you select "Y" here, you can disable actual use of the APM 933 BIOS by passing the "apm=off" option to the kernel at boot time. 934 935 Note that the APM support is almost completely disabled for 936 machines with more than one CPU. 937 938 In order to use APM, you will need supporting software. For location 939 and more information, read <file:Documentation/pm.txt> and the 940 Battery Powered Linux mini-HOWTO, available from 941 <http://www.tldp.org/docs.html#howto>. 942 943 This driver does not spin down disk drives (see the hdparm(8) 944 manpage ("man 8 hdparm") for that), and it doesn't turn off 945 VESA-compliant "green" monitors. 946 947 This driver does not support the TI 4000M TravelMate and the ACER 948 486/DX4/75 because they don't have compliant BIOSes. Many "green" 949 desktop machines also don't have compliant BIOSes, and this driver 950 may cause those machines to panic during the boot phase. 951 952 Generally, if you don't have a battery in your machine, there isn't 953 much point in using this driver and you should say N. If you get 954 random kernel OOPSes or reboots that don't seem to be related to 955 anything, try disabling/enabling this option (or disabling/enabling 956 APM in your BIOS). 957 958 Some other things you should try when experiencing seemingly random, 959 "weird" problems: 960 961 1) make sure that you have enough swap space and that it is 962 enabled. 963 2) pass the "no-hlt" option to the kernel 964 3) switch on floating point emulation in the kernel and pass 965 the "no387" option to the kernel 966 4) pass the "floppy=nodma" option to the kernel 967 5) pass the "mem=4M" option to the kernel (thereby disabling 968 all but the first 4 MB of RAM) 969 6) make sure that the CPU is not over clocked. 970 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 971 8) disable the cache from your BIOS settings 972 9) install a fan for the video card or exchange video RAM 973 10) install a better fan for the CPU 974 11) exchange RAM chips 975 12) exchange the motherboard. 976 977 To compile this driver as a module, choose M here: the 978 module will be called apm. 979 980config APM_IGNORE_USER_SUSPEND 981 bool "Ignore USER SUSPEND" 982 depends on APM 983 help 984 This option will ignore USER SUSPEND requests. On machines with a 985 compliant APM BIOS, you want to say N. However, on the NEC Versa M 986 series notebooks, it is necessary to say Y because of a BIOS bug. 987 988config APM_DO_ENABLE 989 bool "Enable PM at boot time" 990 depends on APM 991 ---help--- 992 Enable APM features at boot time. From page 36 of the APM BIOS 993 specification: "When disabled, the APM BIOS does not automatically 994 power manage devices, enter the Standby State, enter the Suspend 995 State, or take power saving steps in response to CPU Idle calls." 996 This driver will make CPU Idle calls when Linux is idle (unless this 997 feature is turned off -- see "Do CPU IDLE calls", below). This 998 should always save battery power, but more complicated APM features 999 will be dependent on your BIOS implementation. You may need to turn 1000 this option off if your computer hangs at boot time when using APM 1001 support, or if it beeps continuously instead of suspending. Turn 1002 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 1003 T400CDT. This is off by default since most machines do fine without 1004 this feature. 1005 1006config APM_CPU_IDLE 1007 bool "Make CPU Idle calls when idle" 1008 depends on APM 1009 help 1010 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 1011 On some machines, this can activate improved power savings, such as 1012 a slowed CPU clock rate, when the machine is idle. These idle calls 1013 are made after the idle loop has run for some length of time (e.g., 1014 333 mS). On some machines, this will cause a hang at boot time or 1015 whenever the CPU becomes idle. (On machines with more than one CPU, 1016 this option does nothing.) 1017 1018config APM_DISPLAY_BLANK 1019 bool "Enable console blanking using APM" 1020 depends on APM 1021 help 1022 Enable console blanking using the APM. Some laptops can use this to 1023 turn off the LCD backlight when the screen blanker of the Linux 1024 virtual console blanks the screen. Note that this is only used by 1025 the virtual console screen blanker, and won't turn off the backlight 1026 when using the X Window system. This also doesn't have anything to 1027 do with your VESA-compliant power-saving monitor. Further, this 1028 option doesn't work for all laptops -- it might not turn off your 1029 backlight at all, or it might print a lot of errors to the console, 1030 especially if you are using gpm. 1031 1032config APM_RTC_IS_GMT 1033 bool "RTC stores time in GMT" 1034 depends on APM 1035 help 1036 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock) 1037 stores the time in GMT (Greenwich Mean Time). Say N if your RTC 1038 stores localtime. 1039 1040 It is in fact recommended to store GMT in your RTC, because then you 1041 don't have to worry about daylight savings time changes. The only 1042 reason not to use GMT in your RTC is if you also run a broken OS 1043 that doesn't understand GMT. 1044 1045config APM_ALLOW_INTS 1046 bool "Allow interrupts during APM BIOS calls" 1047 depends on APM 1048 help 1049 Normally we disable external interrupts while we are making calls to 1050 the APM BIOS as a measure to lessen the effects of a badly behaving 1051 BIOS implementation. The BIOS should reenable interrupts if it 1052 needs to. Unfortunately, some BIOSes do not -- especially those in 1053 many of the newer IBM Thinkpads. If you experience hangs when you 1054 suspend, try setting this to Y. Otherwise, say N. 1055 1056config APM_REAL_MODE_POWER_OFF 1057 bool "Use real mode APM BIOS call to power off" 1058 depends on APM 1059 help 1060 Use real mode APM BIOS calls to switch off the computer. This is 1061 a work-around for a number of buggy BIOSes. Switch this option on if 1062 your computer crashes instead of powering off properly. 1063 1064endmenu 1065 1066source "arch/i386/kernel/cpu/cpufreq/Kconfig" 1067 1068endmenu 1069 1070menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)" 1071 1072config PCI 1073 bool "PCI support" if !X86_VISWS 1074 depends on !X86_VOYAGER 1075 default y if X86_VISWS 1076 help 1077 Find out whether you have a PCI motherboard. PCI is the name of a 1078 bus system, i.e. the way the CPU talks to the other stuff inside 1079 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 1080 VESA. If you have PCI, say Y, otherwise N. 1081 1082 The PCI-HOWTO, available from 1083 <http://www.tldp.org/docs.html#howto>, contains valuable 1084 information about which PCI hardware does work under Linux and which 1085 doesn't. 1086 1087choice 1088 prompt "PCI access mode" 1089 depends on PCI && !X86_VISWS 1090 default PCI_GOANY 1091 ---help--- 1092 On PCI systems, the BIOS can be used to detect the PCI devices and 1093 determine their configuration. However, some old PCI motherboards 1094 have BIOS bugs and may crash if this is done. Also, some embedded 1095 PCI-based systems don't have any BIOS at all. Linux can also try to 1096 detect the PCI hardware directly without using the BIOS. 1097 1098 With this option, you can specify how Linux should detect the 1099 PCI devices. If you choose "BIOS", the BIOS will be used, 1100 if you choose "Direct", the BIOS won't be used, and if you 1101 choose "MMConfig", then PCI Express MMCONFIG will be used. 1102 If you choose "Any", the kernel will try MMCONFIG, then the 1103 direct access method and falls back to the BIOS if that doesn't 1104 work. If unsure, go with the default, which is "Any". 1105 1106config PCI_GOBIOS 1107 bool "BIOS" 1108 1109config PCI_GOMMCONFIG 1110 bool "MMConfig" 1111 1112config PCI_GODIRECT 1113 bool "Direct" 1114 1115config PCI_GOANY 1116 bool "Any" 1117 1118endchoice 1119 1120config PCI_BIOS 1121 bool 1122 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY) 1123 default y 1124 1125config PCI_DIRECT 1126 bool 1127 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS) 1128 default y 1129 1130config PCI_MMCONFIG 1131 bool 1132 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY) 1133 default y 1134 1135source "drivers/pci/pcie/Kconfig" 1136 1137source "drivers/pci/Kconfig" 1138 1139config ISA_DMA_API 1140 bool 1141 default y 1142 1143config ISA 1144 bool "ISA support" 1145 depends on !(X86_VOYAGER || X86_VISWS) 1146 help 1147 Find out whether you have ISA slots on your motherboard. ISA is the 1148 name of a bus system, i.e. the way the CPU talks to the other stuff 1149 inside your box. Other bus systems are PCI, EISA, MicroChannel 1150 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 1151 newer boards don't support it. If you have ISA, say Y, otherwise N. 1152 1153config EISA 1154 bool "EISA support" 1155 depends on ISA 1156 ---help--- 1157 The Extended Industry Standard Architecture (EISA) bus was 1158 developed as an open alternative to the IBM MicroChannel bus. 1159 1160 The EISA bus provided some of the features of the IBM MicroChannel 1161 bus while maintaining backward compatibility with cards made for 1162 the older ISA bus. The EISA bus saw limited use between 1988 and 1163 1995 when it was made obsolete by the PCI bus. 1164 1165 Say Y here if you are building a kernel for an EISA-based machine. 1166 1167 Otherwise, say N. 1168 1169source "drivers/eisa/Kconfig" 1170 1171config MCA 1172 bool "MCA support" if !(X86_VISWS || X86_VOYAGER) 1173 default y if X86_VOYAGER 1174 help 1175 MicroChannel Architecture is found in some IBM PS/2 machines and 1176 laptops. It is a bus system similar to PCI or ISA. See 1177 <file:Documentation/mca.txt> (and especially the web page given 1178 there) before attempting to build an MCA bus kernel. 1179 1180source "drivers/mca/Kconfig" 1181 1182config SCx200 1183 tristate "NatSemi SCx200 support" 1184 depends on !X86_VOYAGER 1185 help 1186 This provides basic support for National Semiconductor's 1187 (now AMD's) Geode processors. The driver probes for the 1188 PCI-IDs of several on-chip devices, so its a good dependency 1189 for other scx200_* drivers. 1190 1191 If compiled as a module, the driver is named scx200. 1192 1193config SCx200HR_TIMER 1194 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 1195 depends on SCx200 && GENERIC_TIME 1196 default y 1197 help 1198 This driver provides a clocksource built upon the on-chip 1199 27MHz high-resolution timer. Its also a workaround for 1200 NSC Geode SC-1100's buggy TSC, which loses time when the 1201 processor goes idle (as is done by the scheduler). The 1202 other workaround is idle=poll boot option. 1203 1204config K8_NB 1205 def_bool y 1206 depends on AGP_AMD64 1207 1208source "drivers/pcmcia/Kconfig" 1209 1210source "drivers/pci/hotplug/Kconfig" 1211 1212endmenu 1213 1214menu "Executable file formats" 1215 1216source "fs/Kconfig.binfmt" 1217 1218endmenu 1219 1220source "net/Kconfig" 1221 1222source "drivers/Kconfig" 1223 1224source "fs/Kconfig" 1225 1226menu "Instrumentation Support" 1227 depends on EXPERIMENTAL 1228 1229source "arch/i386/oprofile/Kconfig" 1230 1231config KPROBES 1232 bool "Kprobes (EXPERIMENTAL)" 1233 depends on KALLSYMS && EXPERIMENTAL && MODULES 1234 help 1235 Kprobes allows you to trap at almost any kernel address and 1236 execute a callback function. register_kprobe() establishes 1237 a probepoint and specifies the callback. Kprobes is useful 1238 for kernel debugging, non-intrusive instrumentation and testing. 1239 If in doubt, say "N". 1240endmenu 1241 1242source "arch/i386/Kconfig.debug" 1243 1244source "security/Kconfig" 1245 1246source "crypto/Kconfig" 1247 1248source "lib/Kconfig" 1249 1250# 1251# Use the generic interrupt handling code in kernel/irq/: 1252# 1253config GENERIC_HARDIRQS 1254 bool 1255 default y 1256 1257config GENERIC_IRQ_PROBE 1258 bool 1259 default y 1260 1261config GENERIC_PENDING_IRQ 1262 bool 1263 depends on GENERIC_HARDIRQS && SMP 1264 default y 1265 1266config X86_SMP 1267 bool 1268 depends on SMP && !X86_VOYAGER 1269 default y 1270 1271config X86_HT 1272 bool 1273 depends on SMP && !(X86_VISWS || X86_VOYAGER) 1274 default y 1275 1276config X86_BIOS_REBOOT 1277 bool 1278 depends on !(X86_VISWS || X86_VOYAGER) 1279 default y 1280 1281config X86_TRAMPOLINE 1282 bool 1283 depends on X86_SMP || (X86_VOYAGER && SMP) 1284 default y 1285 1286config KTIME_SCALAR 1287 bool 1288 default y