2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
6 mainmenu "Linux Kernel Configuration"
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.
28 config GENERIC_ISA_DMA
35 menu "Processor type and features"
38 prompt "Subarchitecture Type"
44 Choose this option if your computer is a standard PC or compatible.
49 Select this for an AMD Elan processor.
51 Do not use this option for K6/Athlon/Opteron processors!
53 If unsure, choose "PC-compatible" instead.
58 Voyager is a MCA based 32 way capable SMP architecture proprietary
59 to NCR Corp. Machine classes 345x/35xx/4100/51xx are voyager based.
63 If you do not specifically know you have a Voyager based machine,
64 say N here otherwise the kernel you build will not be bootable.
67 bool "NUMAQ (IBM/Sequent)"
71 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
72 multiquad box. This changes the way that processors are bootstrapped,
73 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
74 You will need a new lynxer.elf file to flash your firmware with - send
75 email to <Martin.Bligh@us.ibm.com>.
78 bool "Summit/EXA (IBM x440)"
81 This option is needed for IBM systems that use the Summit/EXA chipset.
82 In particular, it is needed for the x440.
84 If you don't have one of these computers, you should say N here.
87 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
90 This option is needed for the systems that have more than 8 CPUs
91 and if the system is not of any sub-arch type above.
93 If you don't have such a system, you should say N here.
96 bool "SGI 320/540 (Visual Workstation)"
98 The SGI Visual Workstation series is an IA32-based workstation
99 based on SGI systems chips with some legacy PC hardware attached.
101 Say Y here to create a kernel to run on the SGI 320 or 540.
103 A kernel compiled for the Visual Workstation will not run on PCs
104 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
106 config X86_GENERICARCH
107 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
110 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
111 It is intended for a generic binary kernel.
114 bool "Support for Unisys ES7000 IA32 series"
117 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
118 supposed to run on an IA32-based Unisys ES7000 system.
119 Only choose this option if you have such a system, otherwise you
127 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
129 config X86_SUMMIT_NUMA
132 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
134 config X86_CYCLONE_TIMER
137 depends on X86_SUMMIT || X86_GENERICARCH
139 config ES7000_CLUSTERED_APIC
142 depends on SMP && X86_ES7000 && MPENTIUMIII
147 prompt "Processor family"
153 This is the processor type of your CPU. This information is used for
154 optimizing purposes. In order to compile a kernel that can run on
155 all x86 CPU types (albeit not optimally fast), you can specify
158 The kernel will not necessarily run on earlier architectures than
159 the one you have chosen, e.g. a Pentium optimized kernel will run on
160 a PPro, but not necessarily on a i486.
162 Here are the settings recommended for greatest speed:
163 - "386" for the AMD/Cyrix/Intel 386DX/DXL/SL/SLC/SX, Cyrix/TI
164 486DLC/DLC2, UMC 486SX-S and NexGen Nx586. Only "386" kernels
165 will run on a 386 class machine.
166 - "486" for the AMD/Cyrix/IBM/Intel 486DX/DX2/DX4 or
167 SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or U5S.
168 - "586" for generic Pentium CPUs lacking the TSC
169 (time stamp counter) register.
170 - "Pentium-Classic" for the Intel Pentium.
171 - "Pentium-MMX" for the Intel Pentium MMX.
172 - "Pentium-Pro" for the Intel Pentium Pro.
173 - "Pentium-II" for the Intel Pentium II or pre-Coppermine Celeron.
174 - "Pentium-III" for the Intel Pentium III or Coppermine Celeron.
175 - "Pentium-4" for the Intel Pentium 4 or P4-based Celeron.
176 - "K6" for the AMD K6, K6-II and K6-III (aka K6-3D).
177 - "Athlon" for the AMD K7 family (Athlon/Duron/Thunderbird).
178 - "Crusoe" for the Transmeta Crusoe series.
179 - "Winchip-C6" for original IDT Winchip.
180 - "Winchip-2" for IDT Winchip 2.
181 - "Winchip-2A" for IDT Winchips with 3dNow! capabilities.
182 - "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
183 - "VIA C3-2 for VIA C3-2 "Nehemiah" (model 9 and above).
185 If you don't know what to do, choose "386".
190 Select this for a 486 series processor, either Intel or one of the
191 compatible processors from AMD, Cyrix, IBM, or Intel. Includes DX,
192 DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
196 bool "586/K5/5x86/6x86/6x86MX"
198 Select this for an 586 or 686 series processor such as the AMD K5,
199 the Intel 5x86 or 6x86, or the Intel 6x86MX. This choice does not
200 assume the RDTSC (Read Time Stamp Counter) instruction.
203 bool "Pentium-Classic"
205 Select this for a Pentium Classic processor with the RDTSC (Read
206 Time Stamp Counter) instruction for benchmarking.
211 Select this for a Pentium with the MMX graphics/multimedia
212 extended instructions.
217 Select this for Intel Pentium Pro chips. This enables the use of
218 Pentium Pro extended instructions, and disables the init-time guard
219 against the f00f bug found in earlier Pentiums.
222 bool "Pentium-II/Celeron(pre-Coppermine)"
224 Select this for Intel chips based on the Pentium-II and
225 pre-Coppermine Celeron core. This option enables an unaligned
226 copy optimization, compiles the kernel with optimization flags
227 tailored for the chip, and applies any applicable Pentium Pro
231 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
233 Select this for Intel chips based on the Pentium-III and
234 Celeron-Coppermine core. This option enables use of some
235 extended prefetch instructions in addition to the Pentium II
241 Select this for Intel Pentium M (not Pentium-4 M)
245 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
247 Select this for Intel Pentium 4 chips. This includes the
248 Pentium 4, P4-based Celeron and Xeon, and Pentium-4 M
249 (not Pentium M) chips. This option enables compile flags
250 optimized for the chip, uses the correct cache shift, and
251 applies any applicable Pentium III optimizations.
254 bool "K6/K6-II/K6-III"
256 Select this for an AMD K6-family processor. Enables use of
257 some extended instructions, and passes appropriate optimization
261 bool "Athlon/Duron/K7"
263 Select this for an AMD Athlon K7-family processor. Enables use of
264 some extended instructions, and passes appropriate optimization
268 bool "Opteron/Athlon64/Hammer/K8"
270 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
271 use of some extended instructions, and passes appropriate optimization
277 Select this for a Transmeta Crusoe processor. Treats the processor
278 like a 586 with TSC, and sets some GCC optimization flags (like a
279 Pentium Pro with no alignment requirements).
284 Select this for an IDT Winchip C6 chip. Linux and GCC
285 treat this chip as a 586TSC with some extended instructions
286 and alignment requirements.
291 Select this for an IDT Winchip-2. Linux and GCC
292 treat this chip as a 586TSC with some extended instructions
293 and alignment requirements.
296 bool "Winchip-2A/Winchip-3"
298 Select this for an IDT Winchip-2A or 3. Linux and GCC
299 treat this chip as a 586TSC with some extended instructions
300 and alignment reqirements. Also enable out of order memory
301 stores for this CPU, which can increase performance of some
305 bool "CyrixIII/VIA-C3"
307 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
308 treat this chip as a generic 586. Whilst the CPU is 686 class,
309 it lacks the cmov extension which gcc assumes is present when
311 Note that Nehemiah (Model 9) and above will not boot with this
312 kernel due to them lacking the 3DNow! instructions used in earlier
313 incarnations of the CPU.
316 bool "VIA C3-2 (Nehemiah)"
318 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
319 of SSE and tells gcc to treat the CPU as a 686.
320 Note, this kernel will not boot on older (pre model 9) C3s.
325 bool "Generic x86 support"
327 Instead of just including optimizations for the selected
328 x86 variant (e.g. PII, Crusoe or Athlon), include some more
329 generic optimizations as well. This will make the kernel
330 perform better on x86 CPUs other than that selected.
332 This is really intended for distributors who need more
333 generic optimizations.
338 # Define implied options from the CPU selection here
350 config X86_L1_CACHE_SHIFT
352 default "7" if MPENTIUM4 || X86_GENERIC
353 default "4" if X86_ELAN || M486 || M386
354 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2
355 default "6" if MK7 || MK8 || MPENTIUMM
357 config RWSEM_GENERIC_SPINLOCK
362 config RWSEM_XCHGADD_ALGORITHM
367 config X86_PPRO_FENCE
369 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386
374 depends on M586MMX || M586TSC || M586 || M486 || M386
377 config X86_WP_WORKS_OK
397 config X86_ALIGNMENT_16
399 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2
404 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8
407 config X86_INTEL_USERCOPY
409 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7
412 config X86_USE_PPRO_CHECKSUM
414 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2
419 depends on MCYRIXIII || MK7
424 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
428 bool "HPET Timer Support"
430 This enables the use of the HPET for the kernel's internal timer.
431 HPET is the next generation timer replacing legacy 8254s.
432 You can safely choose Y here. However, HPET will only be
433 activated if the platform and the BIOS support this feature.
434 Otherwise the 8254 will be used for timing services.
436 Choose N to continue using the legacy 8254 timer.
438 config HPET_EMULATE_RTC
439 def_bool HPET_TIMER && RTC=y
442 bool "Symmetric multi-processing support"
444 This enables support for systems with more than one CPU. If you have
445 a system with only one CPU, like most personal computers, say N. If
446 you have a system with more than one CPU, say Y.
448 If you say N here, the kernel will run on single and multiprocessor
449 machines, but will use only one CPU of a multiprocessor machine. If
450 you say Y here, the kernel will run on many, but not all,
451 singleprocessor machines. On a singleprocessor machine, the kernel
452 will run faster if you say N here.
454 Note that if you say Y here and choose architecture "586" or
455 "Pentium" under "Processor family", the kernel will not work on 486
456 architectures. Similarly, multiprocessor kernels for the "PPro"
457 architecture may not work on all Pentium based boards.
459 People using multiprocessor machines who say Y here should also say
460 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
461 Management" code will be disabled if you say Y here.
463 See also the <file:Documentation/smp.txt>,
464 <file:Documentation/i386/IO-APIC.txt>,
465 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
466 <http://www.tldp.org/docs.html#howto>.
468 If you don't know what to do here, say N.
471 int "Maximum number of CPUs (2-255)"
474 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
477 This allows you to specify the maximum number of CPUs which this
478 kernel will support. The maximum supported value is 255 and the
479 minimum value which makes sense is 2.
481 This is purely to save memory - each supported CPU adds
482 approximately eight kilobytes to the kernel image.
485 bool "SMT (Hyperthreading) scheduler support"
489 SMT scheduler support improves the CPU scheduler's decision making
490 when dealing with Intel Pentium 4 chips with HyperThreading at a
491 cost of slightly increased overhead in some places. If unsure say
495 bool "Preemptible Kernel"
497 This option reduces the latency of the kernel when reacting to
498 real-time or interactive events by allowing a low priority process to
499 be preempted even if it is in kernel mode executing a system call.
500 This allows applications to run more reliably even when the system is
503 Say Y here if you are building a kernel for a desktop, embedded
504 or real-time system. Say N if you are unsure.
507 bool "Local APIC support on uniprocessors" if !SMP
508 depends on !(X86_VISWS || X86_VOYAGER)
510 A local APIC (Advanced Programmable Interrupt Controller) is an
511 integrated interrupt controller in the CPU. If you have a single-CPU
512 system which has a processor with a local APIC, you can say Y here to
513 enable and use it. If you say Y here even though your machine doesn't
514 have a local APIC, then the kernel will still run with no slowdown at
515 all. The local APIC supports CPU-generated self-interrupts (timer,
516 performance counters), and the NMI watchdog which detects hard
519 If you have a system with several CPUs, you do not need to say Y
520 here: the local APIC will be used automatically.
523 bool "IO-APIC support on uniprocessors"
524 depends on !SMP && X86_UP_APIC
526 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
527 SMP-capable replacement for PC-style interrupt controllers. Most
528 SMP systems and a small number of uniprocessor systems have one.
529 If you have a single-CPU system with an IO-APIC, you can say Y here
530 to use it. If you say Y here even though your machine doesn't have
531 an IO-APIC, then the kernel will still run with no slowdown at all.
533 If you have a system with several CPUs, you do not need to say Y
534 here: the IO-APIC will be used automatically.
536 config X86_LOCAL_APIC
538 depends on !SMP && X86_UP_APIC
543 depends on !SMP && X86_UP_IOAPIC
548 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2) && !X86_NUMAQ
552 bool "Machine Check Exception"
553 depends on !X86_VOYAGER
555 Machine Check Exception support allows the processor to notify the
556 kernel if it detects a problem (e.g. overheating, component failure).
557 The action the kernel takes depends on the severity of the problem,
558 ranging from a warning message on the console, to halting the machine.
559 Your processor must be a Pentium or newer to support this - check the
560 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
561 have a design flaw which leads to false MCE events - hence MCE is
562 disabled on all P5 processors, unless explicitly enabled with "mce"
563 as a boot argument. Similarly, if MCE is built in and creates a
564 problem on some new non-standard machine, you can boot with "nomce"
565 to disable it. MCE support simply ignores non-MCE processors like
566 the 386 and 486, so nearly everyone can say Y here.
568 config X86_MCE_NONFATAL
569 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
572 Enabling this feature starts a timer that triggers every 5 seconds which
573 will look at the machine check registers to see if anything happened.
574 Non-fatal problems automatically get corrected (but still logged).
575 Disable this if you don't want to see these messages.
576 Seeing the messages this option prints out may be indicative of dying hardware,
577 or out-of-spec (ie, overclocked) hardware.
578 This option only does something on certain CPUs.
579 (AMD Athlon/Duron and Intel Pentium 4)
581 config X86_MCE_P4THERMAL
582 bool "check for P4 thermal throttling interrupt."
583 depends on X86_MCE && (X86_UP_APIC || SMP)
585 Enabling this feature will cause a message to be printed when the P4
586 enters thermal throttling.
589 tristate "Toshiba Laptop support"
591 This adds a driver to safely access the System Management Mode of
592 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
593 not work on models with a Phoenix BIOS. The System Management Mode
594 is used to set the BIOS and power saving options on Toshiba portables.
596 For information on utilities to make use of this driver see the
597 Toshiba Linux utilities web site at:
598 <http://www.buzzard.org.uk/toshiba/>.
600 Say Y if you intend to run this kernel on a Toshiba portable.
604 tristate "Dell laptop support"
606 This adds a driver to safely access the System Management Mode
607 of the CPU on the Dell Inspiron 8000. The System Management Mode
608 is used to read cpu temperature and cooling fan status and to
609 control the fans on the I8K portables.
611 This driver has been tested only on the Inspiron 8000 but it may
612 also work with other Dell laptops. You can force loading on other
613 models by passing the parameter `force=1' to the module. Use at
616 For information on utilities to make use of this driver see the
617 I8K Linux utilities web site at:
618 <http://people.debian.org/~dz/i8k/>
620 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
624 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
626 If you say Y here and also to "/dev file system support" in the
627 'File systems' section, you will be able to update the microcode on
628 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
629 Pentium III, Pentium 4, Xeon etc. You will obviously need the
630 actual microcode binary data itself which is not shipped with the
633 For latest news and information on obtaining all the required
634 ingredients for this driver, check:
635 <http://www.urbanmyth.org/microcode/>.
637 To compile this driver as a module, choose M here: the
638 module will be called microcode.
641 tristate "/dev/cpu/*/msr - Model-specific register support"
643 This device gives privileged processes access to the x86
644 Model-Specific Registers (MSRs). It is a character device with
645 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
646 MSR accesses are directed to a specific CPU on multi-processor
650 tristate "/dev/cpu/*/cpuid - CPU information support"
652 This device gives processes access to the x86 CPUID instruction to
653 be executed on a specific processor. It is a character device
654 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
657 source "drivers/firmware/Kconfig"
660 prompt "High Memory Support"
666 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
667 However, the address space of 32-bit x86 processors is only 4
668 Gigabytes large. That means that, if you have a large amount of
669 physical memory, not all of it can be "permanently mapped" by the
670 kernel. The physical memory that's not permanently mapped is called
673 If you are compiling a kernel which will never run on a machine with
674 more than 1 Gigabyte total physical RAM, answer "off" here (default
675 choice and suitable for most users). This will result in a "3GB/1GB"
676 split: 3GB are mapped so that each process sees a 3GB virtual memory
677 space and the remaining part of the 4GB virtual memory space is used
678 by the kernel to permanently map as much physical memory as
681 If the machine has between 1 and 4 Gigabytes physical RAM, then
684 If more than 4 Gigabytes is used then answer "64GB" here. This
685 selection turns Intel PAE (Physical Address Extension) mode on.
686 PAE implements 3-level paging on IA32 processors. PAE is fully
687 supported by Linux, PAE mode is implemented on all recent Intel
688 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
689 then the kernel will not boot on CPUs that don't support PAE!
691 The actual amount of total physical memory will either be
692 auto detected or can be forced by using a kernel command line option
693 such as "mem=256M". (Try "man bootparam" or see the documentation of
694 your boot loader (lilo or loadlin) about how to pass options to the
695 kernel at boot time.)
697 If unsure, say "off".
702 Select this if you have a 32-bit processor and between 1 and 4
703 gigabytes of physical RAM.
708 Select this if you have a 32-bit processor and more than 4
709 gigabytes of physical RAM.
715 depends on HIGHMEM64G || HIGHMEM4G
720 depends on HIGHMEM64G
723 # Common NUMA Features
725 bool "Numa Memory Allocation and Scheduler Support"
726 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
728 default y if (X86_NUMAQ || X86_SUMMIT)
730 # Need comments to help the hapless user trying to turn on NUMA support
731 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
732 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
734 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
735 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
742 config HAVE_ARCH_BOOTMEM_NODE
748 bool "Allocate 3rd-level pagetables from highmem"
749 depends on HIGHMEM4G || HIGHMEM64G
751 The VM uses one page table entry for each page of physical memory.
752 For systems with a lot of RAM, this can be wasteful of precious
753 low memory. Setting this option will put user-space page table
754 entries in high memory.
756 config MATH_EMULATION
757 bool "Math emulation"
759 Linux can emulate a math coprocessor (used for floating point
760 operations) if you don't have one. 486DX and Pentium processors have
761 a math coprocessor built in, 486SX and 386 do not, unless you added
762 a 487DX or 387, respectively. (The messages during boot time can
763 give you some hints here ["man dmesg"].) Everyone needs either a
764 coprocessor or this emulation.
766 If you don't have a math coprocessor, you need to say Y here; if you
767 say Y here even though you have a coprocessor, the coprocessor will
768 be used nevertheless. (This behavior can be changed with the kernel
769 command line option "no387", which comes handy if your coprocessor
770 is broken. Try "man bootparam" or see the documentation of your boot
771 loader (lilo or loadlin) about how to pass options to the kernel at
772 boot time.) This means that it is a good idea to say Y here if you
773 intend to use this kernel on different machines.
775 More information about the internals of the Linux math coprocessor
776 emulation can be found in <file:arch/i386/math-emu/README>.
778 If you are not sure, say Y; apart from resulting in a 66 KB bigger
779 kernel, it won't hurt.
782 bool "MTRR (Memory Type Range Register) support"
784 On Intel P6 family processors (Pentium Pro, Pentium II and later)
785 the Memory Type Range Registers (MTRRs) may be used to control
786 processor access to memory ranges. This is most useful if you have
787 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
788 allows bus write transfers to be combined into a larger transfer
789 before bursting over the PCI/AGP bus. This can increase performance
790 of image write operations 2.5 times or more. Saying Y here creates a
791 /proc/mtrr file which may be used to manipulate your processor's
792 MTRRs. Typically the X server should use this.
794 This code has a reasonably generic interface so that similar
795 control registers on other processors can be easily supported
798 The Cyrix 6x86, 6x86MX and M II processors have Address Range
799 Registers (ARRs) which provide a similar functionality to MTRRs. For
800 these, the ARRs are used to emulate the MTRRs.
801 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
802 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
803 write-combining. All of these processors are supported by this code
804 and it makes sense to say Y here if you have one of them.
806 Saying Y here also fixes a problem with buggy SMP BIOSes which only
807 set the MTRRs for the boot CPU and not for the secondary CPUs. This
808 can lead to all sorts of problems, so it's good to say Y here.
810 You can safely say Y even if your machine doesn't have MTRRs, you'll
811 just add about 9 KB to your kernel.
813 See <file:Documentation/mtrr.txt> for more information.
816 bool "Boot from EFI support (EXPERIMENTAL)"
821 This enables the the kernel to boot on EFI platforms using
822 system configuration information passed to it from the firmware.
823 This also enables the kernel to use any EFI runtime services that are
824 available (such as the EFI variable services).
826 This option is only useful on systems that have EFI firmware
827 and will result in a kernel image that is ~8k larger. In addition,
828 you must use the latest ELILO loader available at
829 <http://elilo.sourceforge.net> in order to take advantage of
830 kernel initialization using EFI information (neither GRUB nor LILO know
831 anything about EFI). However, even with this option, the resultant
832 kernel should continue to boot on existing non-EFI platforms.
835 bool "Enable kernel irq balancing"
836 depends on SMP && X86_IO_APIC
839 The default yes will allow the kernel to do irq load balancing.
840 Saying no will keep the kernel from doing irq load balancing.
844 depends on (SMP || PREEMPT) && X86_CMPXCHG
847 # turning this on wastes a bunch of space.
848 # Summit needs it only when NUMA is on
851 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
855 bool "Use register arguments (EXPERIMENTAL)"
856 depends on EXPERIMENTAL
859 Compile the kernel with -mregparm=3. This uses an different ABI
860 and passes the first three arguments of a function call in registers.
861 This will probably break binary only modules.
863 This feature is only enabled for gcc-3.0 and later - earlier compilers
864 generate incorrect output with certain kernel constructs when
870 menu "Power management options (ACPI, APM)"
871 depends on !X86_VOYAGER
873 source kernel/power/Kconfig
875 source "drivers/acpi/Kconfig"
877 menu "APM (Advanced Power Management) BIOS Support"
881 tristate "APM (Advanced Power Management) BIOS support"
884 APM is a BIOS specification for saving power using several different
885 techniques. This is mostly useful for battery powered laptops with
886 APM compliant BIOSes. If you say Y here, the system time will be
887 reset after a RESUME operation, the /proc/apm device will provide
888 battery status information, and user-space programs will receive
889 notification of APM "events" (e.g. battery status change).
891 If you select "Y" here, you can disable actual use of the APM
892 BIOS by passing the "apm=off" option to the kernel at boot time.
894 Note that the APM support is almost completely disabled for
895 machines with more than one CPU.
897 In order to use APM, you will need supporting software. For location
898 and more information, read <file:Documentation/pm.txt> and the
899 Battery Powered Linux mini-HOWTO, available from
900 <http://www.tldp.org/docs.html#howto>.
902 This driver does not spin down disk drives (see the hdparm(8)
903 manpage ("man 8 hdparm") for that), and it doesn't turn off
904 VESA-compliant "green" monitors.
906 This driver does not support the TI 4000M TravelMate and the ACER
907 486/DX4/75 because they don't have compliant BIOSes. Many "green"
908 desktop machines also don't have compliant BIOSes, and this driver
909 may cause those machines to panic during the boot phase.
911 Generally, if you don't have a battery in your machine, there isn't
912 much point in using this driver and you should say N. If you get
913 random kernel OOPSes or reboots that don't seem to be related to
914 anything, try disabling/enabling this option (or disabling/enabling
917 Some other things you should try when experiencing seemingly random,
920 1) make sure that you have enough swap space and that it is
922 2) pass the "no-hlt" option to the kernel
923 3) switch on floating point emulation in the kernel and pass
924 the "no387" option to the kernel
925 4) pass the "floppy=nodma" option to the kernel
926 5) pass the "mem=4M" option to the kernel (thereby disabling
927 all but the first 4 MB of RAM)
928 6) make sure that the CPU is not over clocked.
929 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
930 8) disable the cache from your BIOS settings
931 9) install a fan for the video card or exchange video RAM
932 10) install a better fan for the CPU
933 11) exchange RAM chips
934 12) exchange the motherboard.
936 To compile this driver as a module, choose M here: the
937 module will be called apm.
939 config APM_IGNORE_USER_SUSPEND
940 bool "Ignore USER SUSPEND"
943 This option will ignore USER SUSPEND requests. On machines with a
944 compliant APM BIOS, you want to say N. However, on the NEC Versa M
945 series notebooks, it is necessary to say Y because of a BIOS bug.
948 bool "Enable PM at boot time"
951 Enable APM features at boot time. From page 36 of the APM BIOS
952 specification: "When disabled, the APM BIOS does not automatically
953 power manage devices, enter the Standby State, enter the Suspend
954 State, or take power saving steps in response to CPU Idle calls."
955 This driver will make CPU Idle calls when Linux is idle (unless this
956 feature is turned off -- see "Do CPU IDLE calls", below). This
957 should always save battery power, but more complicated APM features
958 will be dependent on your BIOS implementation. You may need to turn
959 this option off if your computer hangs at boot time when using APM
960 support, or if it beeps continuously instead of suspending. Turn
961 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
962 T400CDT. This is off by default since most machines do fine without
966 bool "Make CPU Idle calls when idle"
969 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
970 On some machines, this can activate improved power savings, such as
971 a slowed CPU clock rate, when the machine is idle. These idle calls
972 are made after the idle loop has run for some length of time (e.g.,
973 333 mS). On some machines, this will cause a hang at boot time or
974 whenever the CPU becomes idle. (On machines with more than one CPU,
975 this option does nothing.)
977 config APM_DISPLAY_BLANK
978 bool "Enable console blanking using APM"
981 Enable console blanking using the APM. Some laptops can use this to
982 turn off the LCD backlight when the screen blanker of the Linux
983 virtual console blanks the screen. Note that this is only used by
984 the virtual console screen blanker, and won't turn off the backlight
985 when using the X Window system. This also doesn't have anything to
986 do with your VESA-compliant power-saving monitor. Further, this
987 option doesn't work for all laptops -- it might not turn off your
988 backlight at all, or it might print a lot of errors to the console,
989 especially if you are using gpm.
991 config APM_RTC_IS_GMT
992 bool "RTC stores time in GMT"
995 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
996 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
999 It is in fact recommended to store GMT in your RTC, because then you
1000 don't have to worry about daylight savings time changes. The only
1001 reason not to use GMT in your RTC is if you also run a broken OS
1002 that doesn't understand GMT.
1004 config APM_ALLOW_INTS
1005 bool "Allow interrupts during APM BIOS calls"
1008 Normally we disable external interrupts while we are making calls to
1009 the APM BIOS as a measure to lessen the effects of a badly behaving
1010 BIOS implementation. The BIOS should reenable interrupts if it
1011 needs to. Unfortunately, some BIOSes do not -- especially those in
1012 many of the newer IBM Thinkpads. If you experience hangs when you
1013 suspend, try setting this to Y. Otherwise, say N.
1015 config APM_REAL_MODE_POWER_OFF
1016 bool "Use real mode APM BIOS call to power off"
1019 Use real mode APM BIOS calls to switch off the computer. This is
1020 a work-around for a number of buggy BIOSes. Switch this option on if
1021 your computer crashes instead of powering off properly.
1025 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1030 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1032 config X86_VISWS_APIC
1034 depends on X86_VISWS
1037 config X86_LOCAL_APIC
1039 depends on (X86_VISWS || SMP) && !X86_VOYAGER
1044 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1048 bool "PCI support" if !X86_VISWS
1049 depends on !X86_VOYAGER
1050 default y if X86_VISWS
1052 Find out whether you have a PCI motherboard. PCI is the name of a
1053 bus system, i.e. the way the CPU talks to the other stuff inside
1054 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1055 VESA. If you have PCI, say Y, otherwise N.
1057 The PCI-HOWTO, available from
1058 <http://www.tldp.org/docs.html#howto>, contains valuable
1059 information about which PCI hardware does work under Linux and which
1063 prompt "PCI access mode"
1064 depends on PCI && !X86_VISWS
1067 On PCI systems, the BIOS can be used to detect the PCI devices and
1068 determine their configuration. However, some old PCI motherboards
1069 have BIOS bugs and may crash if this is done. Also, some embedded
1070 PCI-based systems don't have any BIOS at all. Linux can also try to
1071 detect the PCI hardware directly without using the BIOS.
1073 With this option, you can specify how Linux should detect the
1074 PCI devices. If you choose "BIOS", the BIOS will be used,
1075 if you choose "Direct", the BIOS won't be used, and if you
1076 choose "MMConfig", then PCI Express MMCONFIG will be used.
1077 If you choose "Any", the kernel will try MMCONFIG, then the
1078 direct access method and falls back to the BIOS if that doesn't
1079 work. If unsure, go with the default, which is "Any".
1084 config PCI_GOMMCONFIG
1097 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1102 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1107 depends on PCI && (PCI_GOMMCONFIG || PCI_GOANY)
1111 source "drivers/pci/Kconfig"
1115 depends on !(X86_VOYAGER || X86_VISWS)
1117 Find out whether you have ISA slots on your motherboard. ISA is the
1118 name of a bus system, i.e. the way the CPU talks to the other stuff
1119 inside your box. Other bus systems are PCI, EISA, MicroChannel
1120 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1121 newer boards don't support it. If you have ISA, say Y, otherwise N.
1127 The Extended Industry Standard Architecture (EISA) bus was
1128 developed as an open alternative to the IBM MicroChannel bus.
1130 The EISA bus provided some of the features of the IBM MicroChannel
1131 bus while maintaining backward compatibility with cards made for
1132 the older ISA bus. The EISA bus saw limited use between 1988 and
1133 1995 when it was made obsolete by the PCI bus.
1135 Say Y here if you are building a kernel for an EISA-based machine.
1139 source "drivers/eisa/Kconfig"
1143 depends on !(X86_VISWS || X86_VOYAGER)
1145 MicroChannel Architecture is found in some IBM PS/2 machines and
1146 laptops. It is a bus system similar to PCI or ISA. See
1147 <file:Documentation/mca.txt> (and especially the web page given
1148 there) before attempting to build an MCA bus kernel.
1151 depends on X86_VOYAGER
1152 default y if X86_VOYAGER
1154 source "drivers/mca/Kconfig"
1157 tristate "NatSemi SCx200 support"
1158 depends on !X86_VOYAGER
1160 This provides basic support for the National Semiconductor SCx200
1161 processor. Right now this is just a driver for the GPIO pins.
1163 If you don't know what to do here, say N.
1165 This support is also available as a module. If compiled as a
1166 module, it will be called scx200.
1168 source "drivers/pcmcia/Kconfig"
1170 source "drivers/pci/hotplug/Kconfig"
1175 menu "Executable file formats"
1177 source "fs/Kconfig.binfmt"
1181 source "drivers/Kconfig"
1185 source "arch/i386/oprofile/Kconfig"
1188 menu "Kernel hacking"
1191 bool "Kernel debugging"
1193 Say Y here if you are developing drivers or trying to debug and
1194 identify kernel problems.
1197 bool "Early printk" if EMBEDDED
1200 Write kernel log output directly into the VGA buffer or to a serial
1203 This is useful for kernel debugging when your machine crashes very
1204 early before the console code is initialized. For normal operation
1205 it is not recommended because it looks ugly and doesn't cooperate
1206 with klogd/syslogd or the X server. You should normally N here,
1207 unless you want to debug such a crash.
1209 config DEBUG_STACKOVERFLOW
1210 bool "Check for stack overflows"
1211 depends on DEBUG_KERNEL
1213 config DEBUG_STACK_USAGE
1214 bool "Stack utilization instrumentation"
1215 depends on DEBUG_KERNEL
1217 Enables the display of the minimum amount of free stack which each
1218 task has ever had available in the sysrq-T and sysrq-P debug output.
1220 This option will slow down process creation somewhat.
1223 bool "Debug memory allocations"
1224 depends on DEBUG_KERNEL
1226 Say Y here to have the kernel do limited verification on memory
1227 allocation as well as poisoning memory on free to catch use of freed
1231 bool "Magic SysRq key"
1232 depends on DEBUG_KERNEL
1234 If you say Y here, you will have some control over the system even
1235 if the system crashes for example during kernel debugging (e.g., you
1236 will be able to flush the buffer cache to disk, reboot the system
1237 immediately or dump some status information). This is accomplished
1238 by pressing various keys while holding SysRq (Alt+PrintScreen). It
1239 also works on a serial console (on PC hardware at least), if you
1240 send a BREAK and then within 5 seconds a command keypress. The
1241 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
1242 unless you really know what this hack does.
1244 config DEBUG_SPINLOCK
1245 bool "Spinlock debugging"
1246 depends on DEBUG_KERNEL
1248 Say Y here and build SMP to catch missing spinlock initialization
1249 and certain other kinds of spinlock errors commonly made. This is
1250 best used in conjunction with the NMI watchdog so that spinlock
1251 deadlocks are also debuggable.
1253 config DEBUG_PAGEALLOC
1254 bool "Page alloc debugging"
1255 depends on DEBUG_KERNEL
1257 Unmap pages from the kernel linear mapping after free_pages().
1258 This results in a large slowdown, but helps to find certain types
1259 of memory corruptions.
1261 config DEBUG_HIGHMEM
1262 bool "Highmem debugging"
1263 depends on DEBUG_KERNEL && HIGHMEM
1265 This options enables addition error checking for high memory systems.
1266 Disable for production systems.
1269 bool "Compile the kernel with debug info"
1270 depends on DEBUG_KERNEL
1272 If you say Y here the resulting kernel image will include
1273 debugging info resulting in a larger kernel image.
1274 Say Y here only if you plan to use gdb to debug the kernel.
1275 If you don't debug the kernel, you can say N.
1277 config DEBUG_SPINLOCK_SLEEP
1278 bool "Sleep-inside-spinlock checking"
1280 If you say Y here, various routines which may sleep will become very
1281 noisy if they are called with a spinlock held.
1283 config FRAME_POINTER
1284 bool "Compile the kernel with frame pointers"
1286 If you say Y here the resulting kernel image will be slightly larger
1287 and slower, but it will give very useful debugging information.
1288 If you don't debug the kernel, you can say N, but we may not be able
1289 to solve problems without frame pointers.
1292 bool "Use 4Kb for kernel stacks instead of 8Kb"
1294 If you say Y here the kernel will use a 4Kb stacksize for the
1295 kernel stack attached to each process/thread. This facilitates
1296 running more threads on a system and also reduces the pressure
1297 on the VM subsystem for higher order allocations. This option
1298 will also use IRQ stacks to compensate for the reduced stackspace.
1300 config X86_FIND_SMP_CONFIG
1302 depends on X86_LOCAL_APIC || X86_VOYAGER
1307 depends on X86_LOCAL_APIC && !X86_VISWS
1312 source "kernel/vserver/Kconfig"
1314 source "security/Kconfig"
1316 source "crypto/Kconfig"
1318 source "lib/Kconfig"
1322 depends on SMP && !X86_VOYAGER
1327 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1330 config X86_BIOS_REBOOT
1332 depends on !(X86_VISWS || X86_VOYAGER)
1335 config X86_TRAMPOLINE
1337 depends on X86_SMP || (X86_VOYAGER && SMP)
1340 # std_resources is overridden for pc9800, but that's not
1341 # a currently selectable arch choice
1342 config X86_STD_RESOURCES
1348 depends on X86 && !EMBEDDED