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 bool "Provide RTC interrupt"
440 depends on HPET_TIMER && RTC=y
443 bool "Symmetric multi-processing support"
445 This enables support for systems with more than one CPU. If you have
446 a system with only one CPU, like most personal computers, say N. If
447 you have a system with more than one CPU, say Y.
449 If you say N here, the kernel will run on single and multiprocessor
450 machines, but will use only one CPU of a multiprocessor machine. If
451 you say Y here, the kernel will run on many, but not all,
452 singleprocessor machines. On a singleprocessor machine, the kernel
453 will run faster if you say N here.
455 Note that if you say Y here and choose architecture "586" or
456 "Pentium" under "Processor family", the kernel will not work on 486
457 architectures. Similarly, multiprocessor kernels for the "PPro"
458 architecture may not work on all Pentium based boards.
460 People using multiprocessor machines who say Y here should also say
461 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
462 Management" code will be disabled if you say Y here.
464 See also the <file:Documentation/smp.txt>,
465 <file:Documentation/i386/IO-APIC.txt>,
466 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
467 <http://www.tldp.org/docs.html#howto>.
469 If you don't know what to do here, say N.
472 int "Maximum number of CPUs (2-255)"
475 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
478 This allows you to specify the maximum number of CPUs which this
479 kernel will support. The maximum supported value is 255 and the
480 minimum value which makes sense is 2.
482 This is purely to save memory - each supported CPU adds
483 approximately eight kilobytes to the kernel image.
486 bool "SMT (Hyperthreading) scheduler support"
490 SMT scheduler support improves the CPU scheduler's decision making
491 when dealing with Intel Pentium 4 chips with HyperThreading at a
492 cost of slightly increased overhead in some places. If unsure say
496 bool "Preemptible Kernel"
498 This option reduces the latency of the kernel when reacting to
499 real-time or interactive events by allowing a low priority process to
500 be preempted even if it is in kernel mode executing a system call.
501 This allows applications to run more reliably even when the system is
504 Say Y here if you are building a kernel for a desktop, embedded
505 or real-time system. Say N if you are unsure.
508 bool "Local APIC support on uniprocessors" if !SMP
509 depends on !(X86_VISWS || X86_VOYAGER)
511 A local APIC (Advanced Programmable Interrupt Controller) is an
512 integrated interrupt controller in the CPU. If you have a single-CPU
513 system which has a processor with a local APIC, you can say Y here to
514 enable and use it. If you say Y here even though your machine doesn't
515 have a local APIC, then the kernel will still run with no slowdown at
516 all. The local APIC supports CPU-generated self-interrupts (timer,
517 performance counters), and the NMI watchdog which detects hard
520 If you have a system with several CPUs, you do not need to say Y
521 here: the local APIC will be used automatically.
524 bool "IO-APIC support on uniprocessors"
525 depends on !SMP && X86_UP_APIC
527 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
528 SMP-capable replacement for PC-style interrupt controllers. Most
529 SMP systems and a small number of uniprocessor systems have one.
530 If you have a single-CPU system with an IO-APIC, you can say Y here
531 to use it. If you say Y here even though your machine doesn't have
532 an IO-APIC, then the kernel will still run with no slowdown at all.
534 If you have a system with several CPUs, you do not need to say Y
535 here: the IO-APIC will be used automatically.
537 config X86_LOCAL_APIC
539 depends on !SMP && X86_UP_APIC
544 depends on !SMP && X86_UP_IOAPIC
549 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2) && !X86_NUMAQ
553 bool "Machine Check Exception"
554 depends on !X86_VOYAGER
556 Machine Check Exception support allows the processor to notify the
557 kernel if it detects a problem (e.g. overheating, component failure).
558 The action the kernel takes depends on the severity of the problem,
559 ranging from a warning message on the console, to halting the machine.
560 Your processor must be a Pentium or newer to support this - check the
561 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
562 have a design flaw which leads to false MCE events - hence MCE is
563 disabled on all P5 processors, unless explicitly enabled with "mce"
564 as a boot argument. Similarly, if MCE is built in and creates a
565 problem on some new non-standard machine, you can boot with "nomce"
566 to disable it. MCE support simply ignores non-MCE processors like
567 the 386 and 486, so nearly everyone can say Y here.
569 config X86_MCE_NONFATAL
570 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
573 Enabling this feature starts a timer that triggers every 5 seconds which
574 will look at the machine check registers to see if anything happened.
575 Non-fatal problems automatically get corrected (but still logged).
576 Disable this if you don't want to see these messages.
577 Seeing the messages this option prints out may be indicative of dying hardware,
578 or out-of-spec (ie, overclocked) hardware.
579 This option only does something on certain CPUs.
580 (AMD Athlon/Duron and Intel Pentium 4)
582 config X86_MCE_P4THERMAL
583 bool "check for P4 thermal throttling interrupt."
584 depends on X86_MCE && (X86_UP_APIC || SMP)
586 Enabling this feature will cause a message to be printed when the P4
587 enters thermal throttling.
590 tristate "Toshiba Laptop support"
592 This adds a driver to safely access the System Management Mode of
593 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
594 not work on models with a Phoenix BIOS. The System Management Mode
595 is used to set the BIOS and power saving options on Toshiba portables.
597 For information on utilities to make use of this driver see the
598 Toshiba Linux utilities web site at:
599 <http://www.buzzard.org.uk/toshiba/>.
601 Say Y if you intend to run this kernel on a Toshiba portable.
605 tristate "Dell laptop support"
607 This adds a driver to safely access the System Management Mode
608 of the CPU on the Dell Inspiron 8000. The System Management Mode
609 is used to read cpu temperature and cooling fan status and to
610 control the fans on the I8K portables.
612 This driver has been tested only on the Inspiron 8000 but it may
613 also work with other Dell laptops. You can force loading on other
614 models by passing the parameter `force=1' to the module. Use at
617 For information on utilities to make use of this driver see the
618 I8K Linux utilities web site at:
619 <http://people.debian.org/~dz/i8k/>
621 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
625 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
627 If you say Y here and also to "/dev file system support" in the
628 'File systems' section, you will be able to update the microcode on
629 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
630 Pentium III, Pentium 4, Xeon etc. You will obviously need the
631 actual microcode binary data itself which is not shipped with the
634 For latest news and information on obtaining all the required
635 ingredients for this driver, check:
636 <http://www.urbanmyth.org/microcode/>.
638 To compile this driver as a module, choose M here: the
639 module will be called microcode.
642 tristate "/dev/cpu/*/msr - Model-specific register support"
644 This device gives privileged processes access to the x86
645 Model-Specific Registers (MSRs). It is a character device with
646 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
647 MSR accesses are directed to a specific CPU on multi-processor
651 tristate "/dev/cpu/*/cpuid - CPU information support"
653 This device gives processes access to the x86 CPUID instruction to
654 be executed on a specific processor. It is a character device
655 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
658 source "drivers/firmware/Kconfig"
661 prompt "High Memory Support"
667 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
668 However, the address space of 32-bit x86 processors is only 4
669 Gigabytes large. That means that, if you have a large amount of
670 physical memory, not all of it can be "permanently mapped" by the
671 kernel. The physical memory that's not permanently mapped is called
674 If you are compiling a kernel which will never run on a machine with
675 more than 1 Gigabyte total physical RAM, answer "off" here (default
676 choice and suitable for most users). This will result in a "3GB/1GB"
677 split: 3GB are mapped so that each process sees a 3GB virtual memory
678 space and the remaining part of the 4GB virtual memory space is used
679 by the kernel to permanently map as much physical memory as
682 If the machine has between 1 and 4 Gigabytes physical RAM, then
685 If more than 4 Gigabytes is used then answer "64GB" here. This
686 selection turns Intel PAE (Physical Address Extension) mode on.
687 PAE implements 3-level paging on IA32 processors. PAE is fully
688 supported by Linux, PAE mode is implemented on all recent Intel
689 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
690 then the kernel will not boot on CPUs that don't support PAE!
692 The actual amount of total physical memory will either be
693 auto detected or can be forced by using a kernel command line option
694 such as "mem=256M". (Try "man bootparam" or see the documentation of
695 your boot loader (lilo or loadlin) about how to pass options to the
696 kernel at boot time.)
698 If unsure, say "off".
703 Select this if you have a 32-bit processor and between 1 and 4
704 gigabytes of physical RAM.
709 Select this if you have a 32-bit processor and more than 4
710 gigabytes of physical RAM.
716 depends on HIGHMEM64G || HIGHMEM4G
721 depends on HIGHMEM64G
724 # Common NUMA Features
726 bool "Numa Memory Allocation and Scheduler Support"
727 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
729 default y if (X86_NUMAQ || X86_SUMMIT)
731 # Need comments to help the hapless user trying to turn on NUMA support
732 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
733 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
735 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
736 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
743 config HAVE_ARCH_BOOTMEM_NODE
749 bool "Allocate 3rd-level pagetables from highmem"
750 depends on HIGHMEM4G || HIGHMEM64G
752 The VM uses one page table entry for each page of physical memory.
753 For systems with a lot of RAM, this can be wasteful of precious
754 low memory. Setting this option will put user-space page table
755 entries in high memory.
757 config MATH_EMULATION
758 bool "Math emulation"
760 Linux can emulate a math coprocessor (used for floating point
761 operations) if you don't have one. 486DX and Pentium processors have
762 a math coprocessor built in, 486SX and 386 do not, unless you added
763 a 487DX or 387, respectively. (The messages during boot time can
764 give you some hints here ["man dmesg"].) Everyone needs either a
765 coprocessor or this emulation.
767 If you don't have a math coprocessor, you need to say Y here; if you
768 say Y here even though you have a coprocessor, the coprocessor will
769 be used nevertheless. (This behavior can be changed with the kernel
770 command line option "no387", which comes handy if your coprocessor
771 is broken. Try "man bootparam" or see the documentation of your boot
772 loader (lilo or loadlin) about how to pass options to the kernel at
773 boot time.) This means that it is a good idea to say Y here if you
774 intend to use this kernel on different machines.
776 More information about the internals of the Linux math coprocessor
777 emulation can be found in <file:arch/i386/math-emu/README>.
779 If you are not sure, say Y; apart from resulting in a 66 KB bigger
780 kernel, it won't hurt.
783 bool "MTRR (Memory Type Range Register) support"
785 On Intel P6 family processors (Pentium Pro, Pentium II and later)
786 the Memory Type Range Registers (MTRRs) may be used to control
787 processor access to memory ranges. This is most useful if you have
788 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
789 allows bus write transfers to be combined into a larger transfer
790 before bursting over the PCI/AGP bus. This can increase performance
791 of image write operations 2.5 times or more. Saying Y here creates a
792 /proc/mtrr file which may be used to manipulate your processor's
793 MTRRs. Typically the X server should use this.
795 This code has a reasonably generic interface so that similar
796 control registers on other processors can be easily supported
799 The Cyrix 6x86, 6x86MX and M II processors have Address Range
800 Registers (ARRs) which provide a similar functionality to MTRRs. For
801 these, the ARRs are used to emulate the MTRRs.
802 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
803 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
804 write-combining. All of these processors are supported by this code
805 and it makes sense to say Y here if you have one of them.
807 Saying Y here also fixes a problem with buggy SMP BIOSes which only
808 set the MTRRs for the boot CPU and not for the secondary CPUs. This
809 can lead to all sorts of problems, so it's good to say Y here.
811 You can safely say Y even if your machine doesn't have MTRRs, you'll
812 just add about 9 KB to your kernel.
814 See <file:Documentation/mtrr.txt> for more information.
817 bool "Boot from EFI support (EXPERIMENTAL)"
822 This enables the the kernel to boot on EFI platforms using
823 system configuration information passed to it from the firmware.
824 This also enables the kernel to use any EFI runtime services that are
825 available (such as the EFI variable services).
827 This option is only useful on systems that have EFI firmware
828 and will result in a kernel image that is ~8k larger. In addition,
829 you must use the latest ELILO loader available at
830 <http://elilo.sourceforge.net> in order to take advantage of
831 kernel initialization using EFI information (neither GRUB nor LILO know
832 anything about EFI). However, even with this option, the resultant
833 kernel should continue to boot on existing non-EFI platforms.
836 bool "Enable kernel irq balancing"
837 depends on SMP && X86_IO_APIC
840 The default yes will allow the kernel to do irq load balancing.
841 Saying no will keep the kernel from doing irq load balancing.
845 depends on (SMP || PREEMPT) && X86_CMPXCHG
848 # turning this on wastes a bunch of space.
849 # Summit needs it only when NUMA is on
852 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
856 bool "Use register arguments (EXPERIMENTAL)"
857 depends on EXPERIMENTAL
860 Compile the kernel with -mregparm=3. This uses an different ABI
861 and passes the first three arguments of a function call in registers.
862 This will probably break binary only modules.
864 This feature is only enabled for gcc-3.0 and later - earlier compilers
865 generate incorrect output with certain kernel constructs when
871 menu "Power management options (ACPI, APM)"
872 depends on !X86_VOYAGER
874 source kernel/power/Kconfig
876 source "drivers/acpi/Kconfig"
878 menu "APM (Advanced Power Management) BIOS Support"
882 tristate "APM (Advanced Power Management) BIOS support"
885 APM is a BIOS specification for saving power using several different
886 techniques. This is mostly useful for battery powered laptops with
887 APM compliant BIOSes. If you say Y here, the system time will be
888 reset after a RESUME operation, the /proc/apm device will provide
889 battery status information, and user-space programs will receive
890 notification of APM "events" (e.g. battery status change).
892 If you select "Y" here, you can disable actual use of the APM
893 BIOS by passing the "apm=off" option to the kernel at boot time.
895 Note that the APM support is almost completely disabled for
896 machines with more than one CPU.
898 In order to use APM, you will need supporting software. For location
899 and more information, read <file:Documentation/pm.txt> and the
900 Battery Powered Linux mini-HOWTO, available from
901 <http://www.tldp.org/docs.html#howto>.
903 This driver does not spin down disk drives (see the hdparm(8)
904 manpage ("man 8 hdparm") for that), and it doesn't turn off
905 VESA-compliant "green" monitors.
907 This driver does not support the TI 4000M TravelMate and the ACER
908 486/DX4/75 because they don't have compliant BIOSes. Many "green"
909 desktop machines also don't have compliant BIOSes, and this driver
910 may cause those machines to panic during the boot phase.
912 Generally, if you don't have a battery in your machine, there isn't
913 much point in using this driver and you should say N. If you get
914 random kernel OOPSes or reboots that don't seem to be related to
915 anything, try disabling/enabling this option (or disabling/enabling
918 Some other things you should try when experiencing seemingly random,
921 1) make sure that you have enough swap space and that it is
923 2) pass the "no-hlt" option to the kernel
924 3) switch on floating point emulation in the kernel and pass
925 the "no387" option to the kernel
926 4) pass the "floppy=nodma" option to the kernel
927 5) pass the "mem=4M" option to the kernel (thereby disabling
928 all but the first 4 MB of RAM)
929 6) make sure that the CPU is not over clocked.
930 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
931 8) disable the cache from your BIOS settings
932 9) install a fan for the video card or exchange video RAM
933 10) install a better fan for the CPU
934 11) exchange RAM chips
935 12) exchange the motherboard.
937 To compile this driver as a module, choose M here: the
938 module will be called apm.
940 config APM_IGNORE_USER_SUSPEND
941 bool "Ignore USER SUSPEND"
944 This option will ignore USER SUSPEND requests. On machines with a
945 compliant APM BIOS, you want to say N. However, on the NEC Versa M
946 series notebooks, it is necessary to say Y because of a BIOS bug.
949 bool "Enable PM at boot time"
952 Enable APM features at boot time. From page 36 of the APM BIOS
953 specification: "When disabled, the APM BIOS does not automatically
954 power manage devices, enter the Standby State, enter the Suspend
955 State, or take power saving steps in response to CPU Idle calls."
956 This driver will make CPU Idle calls when Linux is idle (unless this
957 feature is turned off -- see "Do CPU IDLE calls", below). This
958 should always save battery power, but more complicated APM features
959 will be dependent on your BIOS implementation. You may need to turn
960 this option off if your computer hangs at boot time when using APM
961 support, or if it beeps continuously instead of suspending. Turn
962 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
963 T400CDT. This is off by default since most machines do fine without
967 bool "Make CPU Idle calls when idle"
970 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
971 On some machines, this can activate improved power savings, such as
972 a slowed CPU clock rate, when the machine is idle. These idle calls
973 are made after the idle loop has run for some length of time (e.g.,
974 333 mS). On some machines, this will cause a hang at boot time or
975 whenever the CPU becomes idle. (On machines with more than one CPU,
976 this option does nothing.)
978 config APM_DISPLAY_BLANK
979 bool "Enable console blanking using APM"
982 Enable console blanking using the APM. Some laptops can use this to
983 turn off the LCD backlight when the screen blanker of the Linux
984 virtual console blanks the screen. Note that this is only used by
985 the virtual console screen blanker, and won't turn off the backlight
986 when using the X Window system. This also doesn't have anything to
987 do with your VESA-compliant power-saving monitor. Further, this
988 option doesn't work for all laptops -- it might not turn off your
989 backlight at all, or it might print a lot of errors to the console,
990 especially if you are using gpm.
992 config APM_RTC_IS_GMT
993 bool "RTC stores time in GMT"
996 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
997 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1000 It is in fact recommended to store GMT in your RTC, because then you
1001 don't have to worry about daylight savings time changes. The only
1002 reason not to use GMT in your RTC is if you also run a broken OS
1003 that doesn't understand GMT.
1005 config APM_ALLOW_INTS
1006 bool "Allow interrupts during APM BIOS calls"
1009 Normally we disable external interrupts while we are making calls to
1010 the APM BIOS as a measure to lessen the effects of a badly behaving
1011 BIOS implementation. The BIOS should reenable interrupts if it
1012 needs to. Unfortunately, some BIOSes do not -- especially those in
1013 many of the newer IBM Thinkpads. If you experience hangs when you
1014 suspend, try setting this to Y. Otherwise, say N.
1016 config APM_REAL_MODE_POWER_OFF
1017 bool "Use real mode APM BIOS call to power off"
1020 Use real mode APM BIOS calls to switch off the computer. This is
1021 a work-around for a number of buggy BIOSes. Switch this option on if
1022 your computer crashes instead of powering off properly.
1026 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1031 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1033 config X86_VISWS_APIC
1035 depends on X86_VISWS
1038 config X86_LOCAL_APIC
1040 depends on (X86_VISWS || SMP) && !X86_VOYAGER
1045 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1049 bool "PCI support" if !X86_VISWS
1050 depends on !X86_VOYAGER
1051 default y if X86_VISWS
1053 Find out whether you have a PCI motherboard. PCI is the name of a
1054 bus system, i.e. the way the CPU talks to the other stuff inside
1055 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1056 VESA. If you have PCI, say Y, otherwise N.
1058 The PCI-HOWTO, available from
1059 <http://www.tldp.org/docs.html#howto>, contains valuable
1060 information about which PCI hardware does work under Linux and which
1064 prompt "PCI access mode"
1065 depends on PCI && !X86_VISWS
1068 On PCI systems, the BIOS can be used to detect the PCI devices and
1069 determine their configuration. However, some old PCI motherboards
1070 have BIOS bugs and may crash if this is done. Also, some embedded
1071 PCI-based systems don't have any BIOS at all. Linux can also try to
1072 detect the PCI hardware directly without using the BIOS.
1074 With this option, you can specify how Linux should detect the
1075 PCI devices. If you choose "BIOS", the BIOS will be used,
1076 if you choose "Direct", the BIOS won't be used, and if you
1077 choose "MMConfig", then PCI Express MMCONFIG will be used.
1078 If you choose "Any", the kernel will try MMCONFIG, then the
1079 direct access method and falls back to the BIOS if that doesn't
1080 work. If unsure, go with the default, which is "Any".
1085 config PCI_GOMMCONFIG
1098 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1103 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1108 depends on PCI && (PCI_GOMMCONFIG || PCI_GOANY)
1112 source "drivers/pci/Kconfig"
1116 depends on !(X86_VOYAGER || X86_VISWS)
1118 Find out whether you have ISA slots on your motherboard. ISA is the
1119 name of a bus system, i.e. the way the CPU talks to the other stuff
1120 inside your box. Other bus systems are PCI, EISA, MicroChannel
1121 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1122 newer boards don't support it. If you have ISA, say Y, otherwise N.
1128 The Extended Industry Standard Architecture (EISA) bus was
1129 developed as an open alternative to the IBM MicroChannel bus.
1131 The EISA bus provided some of the features of the IBM MicroChannel
1132 bus while maintaining backward compatibility with cards made for
1133 the older ISA bus. The EISA bus saw limited use between 1988 and
1134 1995 when it was made obsolete by the PCI bus.
1136 Say Y here if you are building a kernel for an EISA-based machine.
1140 source "drivers/eisa/Kconfig"
1144 depends on !(X86_VISWS || X86_VOYAGER)
1146 MicroChannel Architecture is found in some IBM PS/2 machines and
1147 laptops. It is a bus system similar to PCI or ISA. See
1148 <file:Documentation/mca.txt> (and especially the web page given
1149 there) before attempting to build an MCA bus kernel.
1152 depends on X86_VOYAGER
1153 default y if X86_VOYAGER
1155 source "drivers/mca/Kconfig"
1158 tristate "NatSemi SCx200 support"
1159 depends on !X86_VOYAGER
1161 This provides basic support for the National Semiconductor SCx200
1162 processor. Right now this is just a driver for the GPIO pins.
1164 If you don't know what to do here, say N.
1166 This support is also available as a module. If compiled as a
1167 module, it will be called scx200.
1169 source "drivers/pcmcia/Kconfig"
1171 source "drivers/pci/hotplug/Kconfig"
1176 menu "Executable file formats"
1178 source "fs/Kconfig.binfmt"
1182 source "drivers/Kconfig"
1186 source "arch/i386/oprofile/Kconfig"
1189 menu "Kernel hacking"
1192 bool "Kernel debugging"
1194 Say Y here if you are developing drivers or trying to debug and
1195 identify kernel problems.
1198 bool "Early printk" if EMBEDDED
1201 Write kernel log output directly into the VGA buffer or to a serial
1204 This is useful for kernel debugging when your machine crashes very
1205 early before the console code is initialized. For normal operation
1206 it is not recommended because it looks ugly and doesn't cooperate
1207 with klogd/syslogd or the X server. You should normally N here,
1208 unless you want to debug such a crash.
1210 config DEBUG_STACKOVERFLOW
1211 bool "Check for stack overflows"
1212 depends on DEBUG_KERNEL
1214 config DEBUG_STACK_USAGE
1215 bool "Stack utilization instrumentation"
1216 depends on DEBUG_KERNEL
1218 Enables the display of the minimum amount of free stack which each
1219 task has ever had available in the sysrq-T and sysrq-P debug output.
1221 This option will slow down process creation somewhat.
1224 bool "Debug memory allocations"
1225 depends on DEBUG_KERNEL
1227 Say Y here to have the kernel do limited verification on memory
1228 allocation as well as poisoning memory on free to catch use of freed
1232 bool "Magic SysRq key"
1233 depends on DEBUG_KERNEL
1235 If you say Y here, you will have some control over the system even
1236 if the system crashes for example during kernel debugging (e.g., you
1237 will be able to flush the buffer cache to disk, reboot the system
1238 immediately or dump some status information). This is accomplished
1239 by pressing various keys while holding SysRq (Alt+PrintScreen). It
1240 also works on a serial console (on PC hardware at least), if you
1241 send a BREAK and then within 5 seconds a command keypress. The
1242 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
1243 unless you really know what this hack does.
1245 config DEBUG_SPINLOCK
1246 bool "Spinlock debugging"
1247 depends on DEBUG_KERNEL
1249 Say Y here and build SMP to catch missing spinlock initialization
1250 and certain other kinds of spinlock errors commonly made. This is
1251 best used in conjunction with the NMI watchdog so that spinlock
1252 deadlocks are also debuggable.
1254 config DEBUG_PAGEALLOC
1255 bool "Page alloc debugging"
1256 depends on DEBUG_KERNEL
1258 Unmap pages from the kernel linear mapping after free_pages().
1259 This results in a large slowdown, but helps to find certain types
1260 of memory corruptions.
1262 config DEBUG_HIGHMEM
1263 bool "Highmem debugging"
1264 depends on DEBUG_KERNEL && HIGHMEM
1266 This options enables addition error checking for high memory systems.
1267 Disable for production systems.
1270 bool "Compile the kernel with debug info"
1271 depends on DEBUG_KERNEL
1273 If you say Y here the resulting kernel image will include
1274 debugging info resulting in a larger kernel image.
1275 Say Y here only if you plan to use gdb to debug the kernel.
1276 If you don't debug the kernel, you can say N.
1278 config DEBUG_SPINLOCK_SLEEP
1279 bool "Sleep-inside-spinlock checking"
1281 If you say Y here, various routines which may sleep will become very
1282 noisy if they are called with a spinlock held.
1284 config FRAME_POINTER
1285 bool "Compile the kernel with frame pointers"
1287 If you say Y here the resulting kernel image will be slightly larger
1288 and slower, but it will give very useful debugging information.
1289 If you don't debug the kernel, you can say N, but we may not be able
1290 to solve problems without frame pointers.
1293 bool "Use 4Kb for kernel stacks instead of 8Kb"
1295 If you say Y here the kernel will use a 4Kb stacksize for the
1296 kernel stack attached to each process/thread. This facilitates
1297 running more threads on a system and also reduces the pressure
1298 on the VM subsystem for higher order allocations. This option
1299 will also use IRQ stacks to compensate for the reduced stackspace.
1301 config X86_FIND_SMP_CONFIG
1303 depends on X86_LOCAL_APIC || X86_VOYAGER
1308 depends on X86_LOCAL_APIC && !X86_VISWS
1313 source "kernel/vserver/Kconfig"
1315 source "security/Kconfig"
1317 source "crypto/Kconfig"
1319 source "lib/Kconfig"
1323 depends on SMP && !X86_VOYAGER
1328 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1331 config X86_BIOS_REBOOT
1333 depends on !(X86_VISWS || X86_VOYAGER)
1336 config X86_TRAMPOLINE
1338 depends on X86_SMP || (X86_VOYAGER && SMP)
1343 depends on X86 && !EMBEDDED