2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
27 config GENERIC_CMOS_UPDATE
31 config CLOCKSOURCE_WATCHDOG
35 config GENERIC_CLOCKEVENTS
39 config GENERIC_CLOCKEVENTS_BROADCAST
42 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
44 config LOCKDEP_SUPPORT
48 config STACKTRACE_SUPPORT
52 config SEMAPHORE_SLEEPERS
71 config GENERIC_ISA_DMA
84 config GENERIC_HWEIGHT
88 config ARCH_MAY_HAVE_PC_FDC
96 config RWSEM_GENERIC_SPINLOCK
99 config RWSEM_XCHGADD_ALGORITHM
102 config ARCH_HAS_ILOG2_U32
105 config ARCH_HAS_ILOG2_U64
108 config GENERIC_CALIBRATE_DELAY
111 config GENERIC_TIME_VSYSCALL
123 config ARCH_POPULATES_NODE_MAP
130 # Use the generic interrupt handling code in kernel/irq/:
131 config GENERIC_HARDIRQS
135 config GENERIC_IRQ_PROBE
139 config GENERIC_PENDING_IRQ
141 depends on GENERIC_HARDIRQS && SMP
146 depends on X86_32 && SMP && !X86_VOYAGER
152 depends on (X86_32 && !(X86_VISWS || X86_VOYAGER)) || (X86_64 && !MK8)
155 config X86_BIOS_REBOOT
157 depends on X86_32 && !(X86_VISWS || X86_VOYAGER)
160 config X86_TRAMPOLINE
162 depends on X86_SMP || (X86_VOYAGER && SMP)
167 source "init/Kconfig"
169 menu "Processor type and features"
171 source "kernel/time/Kconfig"
174 bool "Symmetric multi-processing support"
176 This enables support for systems with more than one CPU. If you have
177 a system with only one CPU, like most personal computers, say N. If
178 you have a system with more than one CPU, say Y.
180 If you say N here, the kernel will run on single and multiprocessor
181 machines, but will use only one CPU of a multiprocessor machine. If
182 you say Y here, the kernel will run on many, but not all,
183 singleprocessor machines. On a singleprocessor machine, the kernel
184 will run faster if you say N here.
186 Note that if you say Y here and choose architecture "586" or
187 "Pentium" under "Processor family", the kernel will not work on 486
188 architectures. Similarly, multiprocessor kernels for the "PPro"
189 architecture may not work on all Pentium based boards.
191 People using multiprocessor machines who say Y here should also say
192 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
193 Management" code will be disabled if you say Y here.
195 See also the <file:Documentation/smp.txt>,
196 <file:Documentation/i386/IO-APIC.txt>,
197 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
198 <http://www.tldp.org/docs.html#howto>.
200 If you don't know what to do here, say N.
203 prompt "Subarchitecture Type"
209 Choose this option if your computer is a standard PC or compatible.
215 Select this for an AMD Elan processor.
217 Do not use this option for K6/Athlon/Opteron processors!
219 If unsure, choose "PC-compatible" instead.
224 select SMP if !BROKEN
226 Voyager is an MCA-based 32-way capable SMP architecture proprietary
227 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
231 If you do not specifically know you have a Voyager based machine,
232 say N here, otherwise the kernel you build will not be bootable.
235 bool "NUMAQ (IBM/Sequent)"
240 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
241 multiquad box. This changes the way that processors are bootstrapped,
242 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
243 You will need a new lynxer.elf file to flash your firmware with - send
244 email to <Martin.Bligh@us.ibm.com>.
247 bool "Summit/EXA (IBM x440)"
248 depends on X86_32 && SMP
250 This option is needed for IBM systems that use the Summit/EXA chipset.
251 In particular, it is needed for the x440.
253 If you don't have one of these computers, you should say N here.
254 If you want to build a NUMA kernel, you must select ACPI.
257 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
258 depends on X86_32 && SMP
260 This option is needed for the systems that have more than 8 CPUs
261 and if the system is not of any sub-arch type above.
263 If you don't have such a system, you should say N here.
266 bool "SGI 320/540 (Visual Workstation)"
269 The SGI Visual Workstation series is an IA32-based workstation
270 based on SGI systems chips with some legacy PC hardware attached.
272 Say Y here to create a kernel to run on the SGI 320 or 540.
274 A kernel compiled for the Visual Workstation will not run on PCs
275 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
277 config X86_GENERICARCH
278 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
281 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
282 It is intended for a generic binary kernel.
283 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
286 bool "Support for Unisys ES7000 IA32 series"
287 depends on X86_32 && SMP
289 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
290 supposed to run on an IA32-based Unisys ES7000 system.
291 Only choose this option if you have such a system, otherwise you
295 bool "Support for ScaleMP vSMP"
296 depends on X86_64 && PCI
298 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
299 supposed to run on these EM64T-based machines. Only choose this option
300 if you have one of these machines.
304 config SCHED_NO_NO_OMIT_FRAME_POINTER
305 bool "Single-depth WCHAN output"
309 Calculate simpler /proc/<PID>/wchan values. If this option
310 is disabled then wchan values will recurse back to the
311 caller function. This provides more accurate wchan values,
312 at the expense of slightly more scheduling overhead.
314 If in doubt, say "Y".
318 depends on X86_32 && !(X86_VISWS || X86_VOYAGER)
320 This changes the kernel so it can modify itself when it is run
321 under a hypervisor, potentially improving performance significantly
322 over full virtualization. However, when run without a hypervisor
323 the kernel is theoretically slower and slightly larger.
325 menuconfig PARAVIRT_GUEST
326 bool "Paravirtualized guest support"
329 Say Y here to get to see options related to running Linux under
330 various hypervisors. This option alone does not add any kernel code.
332 If you say N, all options in this submenu will be skipped and disabled.
336 source "arch/x86/xen/Kconfig"
339 bool "VMI Guest support"
341 depends on !(X86_VISWS || X86_VOYAGER)
343 VMI provides a paravirtualized interface to the VMware ESX server
344 (it could be used by other hypervisors in theory too, but is not
345 at the moment), by linking the kernel to a GPL-ed ROM module
346 provided by the hypervisor.
348 source "arch/x86/lguest/Kconfig"
355 depends on X86_32 && ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
358 config HAVE_ARCH_PARSE_SRAT
363 config X86_SUMMIT_NUMA
366 depends on X86_32 && NUMA && (X86_SUMMIT || X86_GENERICARCH)
368 config X86_CYCLONE_TIMER
371 depends on X86_32 && X86_SUMMIT || X86_GENERICARCH
373 config ES7000_CLUSTERED_APIC
376 depends on SMP && X86_ES7000 && MPENTIUMIII
378 source "arch/x86/Kconfig.cpu"
382 prompt "HPET Timer Support" if X86_32
385 Use the IA-PC HPET (High Precision Event Timer) to manage
386 time in preference to the PIT and RTC, if a HPET is
388 HPET is the next generation timer replacing legacy 8254s.
389 The HPET provides a stable time base on SMP
390 systems, unlike the TSC, but it is more expensive to access,
391 as it is off-chip. You can find the HPET spec at
392 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
394 You can safely choose Y here. However, HPET will only be
395 activated if the platform and the BIOS support this feature.
396 Otherwise the 8254 will be used for timing services.
398 Choose N to continue using the legacy 8254 timer.
400 config HPET_EMULATE_RTC
402 depends on HPET_TIMER && RTC=y
405 # Mark as embedded because too many people got it wrong.
406 # The code disables itself when not needed.
408 bool "GART IOMMU support" if EMBEDDED
412 depends on X86_64 && PCI
414 Support for full DMA access of devices with 32bit memory access only
415 on systems with more than 3GB. This is usually needed for USB,
416 sound, many IDE/SATA chipsets and some other devices.
417 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
418 based hardware IOMMU and a software bounce buffer based IOMMU used
419 on Intel systems and as fallback.
420 The code is only active when needed (enough memory and limited
421 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
425 bool "IBM Calgary IOMMU support"
427 depends on X86_64 && PCI && EXPERIMENTAL
429 Support for hardware IOMMUs in IBM's xSeries x366 and x460
430 systems. Needed to run systems with more than 3GB of memory
431 properly with 32-bit PCI devices that do not support DAC
432 (Double Address Cycle). Calgary also supports bus level
433 isolation, where all DMAs pass through the IOMMU. This
434 prevents them from going anywhere except their intended
435 destination. This catches hard-to-find kernel bugs and
436 mis-behaving drivers and devices that do not use the DMA-API
437 properly to set up their DMA buffers. The IOMMU can be
438 turned off at boot time with the iommu=off parameter.
439 Normally the kernel will make the right choice by itself.
442 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
443 bool "Should Calgary be enabled by default?"
445 depends on CALGARY_IOMMU
447 Should Calgary be enabled by default? if you choose 'y', Calgary
448 will be used (if it exists). If you choose 'n', Calgary will not be
449 used even if it exists. If you choose 'n' and would like to use
450 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
453 # need this always selected by IOMMU for the VIA workaround
457 Support for software bounce buffers used on x86-64 systems
458 which don't have a hardware IOMMU (e.g. the current generation
459 of Intel's x86-64 CPUs). Using this PCI devices which can only
460 access 32-bits of memory can be used on systems with more than
461 3 GB of memory. If unsure, say Y.
465 int "Maximum number of CPUs (2-255)"
468 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
471 This allows you to specify the maximum number of CPUs which this
472 kernel will support. The maximum supported value is 255 and the
473 minimum value which makes sense is 2.
475 This is purely to save memory - each supported CPU adds
476 approximately eight kilobytes to the kernel image.
479 bool "SMT (Hyperthreading) scheduler support"
480 depends on (X86_64 && SMP) || (X86_32 && X86_HT)
482 SMT scheduler support improves the CPU scheduler's decision making
483 when dealing with Intel Pentium 4 chips with HyperThreading at a
484 cost of slightly increased overhead in some places. If unsure say
488 bool "Multi-core scheduler support"
489 depends on (X86_64 && SMP) || (X86_32 && X86_HT)
492 Multi-core scheduler support improves the CPU scheduler's decision
493 making when dealing with multi-core CPU chips at a cost of slightly
494 increased overhead in some places. If unsure say N here.
496 source "kernel/Kconfig.preempt"
499 bool "Local APIC support on uniprocessors"
500 depends on X86_32 && !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
502 A local APIC (Advanced Programmable Interrupt Controller) is an
503 integrated interrupt controller in the CPU. If you have a single-CPU
504 system which has a processor with a local APIC, you can say Y here to
505 enable and use it. If you say Y here even though your machine doesn't
506 have a local APIC, then the kernel will still run with no slowdown at
507 all. The local APIC supports CPU-generated self-interrupts (timer,
508 performance counters), and the NMI watchdog which detects hard
512 bool "IO-APIC support on uniprocessors"
513 depends on X86_UP_APIC
515 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
516 SMP-capable replacement for PC-style interrupt controllers. Most
517 SMP systems and many recent uniprocessor systems have one.
519 If you have a single-CPU system with an IO-APIC, you can say Y here
520 to use it. If you say Y here even though your machine doesn't have
521 an IO-APIC, then the kernel will still run with no slowdown at all.
523 config X86_LOCAL_APIC
525 depends on X86_64 || (X86_32 && (X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH))
530 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH))
533 config X86_VISWS_APIC
535 depends on X86_32 && X86_VISWS
539 bool "Machine Check Exception"
540 depends on !X86_VOYAGER
542 Machine Check Exception support allows the processor to notify the
543 kernel if it detects a problem (e.g. overheating, component failure).
544 The action the kernel takes depends on the severity of the problem,
545 ranging from a warning message on the console, to halting the machine.
546 Your processor must be a Pentium or newer to support this - check the
547 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
548 have a design flaw which leads to false MCE events - hence MCE is
549 disabled on all P5 processors, unless explicitly enabled with "mce"
550 as a boot argument. Similarly, if MCE is built in and creates a
551 problem on some new non-standard machine, you can boot with "nomce"
552 to disable it. MCE support simply ignores non-MCE processors like
553 the 386 and 486, so nearly everyone can say Y here.
556 bool "Intel MCE features"
557 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
560 Additional support for intel specific MCE features such as
564 bool "AMD MCE features"
565 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
568 Additional support for AMD specific MCE features such as
569 the DRAM Error Threshold.
571 config X86_MCE_NONFATAL
572 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
573 depends on X86_32 && X86_MCE
575 Enabling this feature starts a timer that triggers every 5 seconds which
576 will look at the machine check registers to see if anything happened.
577 Non-fatal problems automatically get corrected (but still logged).
578 Disable this if you don't want to see these messages.
579 Seeing the messages this option prints out may be indicative of dying
580 or out-of-spec (ie, overclocked) hardware.
581 This option only does something on certain CPUs.
582 (AMD Athlon/Duron and Intel Pentium 4)
584 config X86_MCE_P4THERMAL
585 bool "check for P4 thermal throttling interrupt."
586 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
588 Enabling this feature will cause a message to be printed when the P4
589 enters thermal throttling.
592 bool "Enable VM86 support" if EMBEDDED
596 This option is required by programs like DOSEMU to run 16-bit legacy
597 code on X86 processors. It also may be needed by software like
598 XFree86 to initialize some video cards via BIOS. Disabling this
599 option saves about 6k.
602 tristate "Toshiba Laptop support"
605 This adds a driver to safely access the System Management Mode of
606 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
607 not work on models with a Phoenix BIOS. The System Management Mode
608 is used to set the BIOS and power saving options on Toshiba portables.
610 For information on utilities to make use of this driver see the
611 Toshiba Linux utilities web site at:
612 <http://www.buzzard.org.uk/toshiba/>.
614 Say Y if you intend to run this kernel on a Toshiba portable.
618 tristate "Dell laptop support"
621 This adds a driver to safely access the System Management Mode
622 of the CPU on the Dell Inspiron 8000. The System Management Mode
623 is used to read cpu temperature and cooling fan status and to
624 control the fans on the I8K portables.
626 This driver has been tested only on the Inspiron 8000 but it may
627 also work with other Dell laptops. You can force loading on other
628 models by passing the parameter `force=1' to the module. Use at
631 For information on utilities to make use of this driver see the
632 I8K Linux utilities web site at:
633 <http://people.debian.org/~dz/i8k/>
635 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
638 config X86_REBOOTFIXUPS
639 bool "Enable X86 board specific fixups for reboot"
640 depends on X86_32 && X86
643 This enables chipset and/or board specific fixups to be done
644 in order to get reboot to work correctly. This is only needed on
645 some combinations of hardware and BIOS. The symptom, for which
646 this config is intended, is when reboot ends with a stalled/hung
649 Currently, the only fixup is for the Geode machines using
650 CS5530A and CS5536 chipsets.
652 Say Y if you want to enable the fixup. Currently, it's safe to
653 enable this option even if you don't need it.
657 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
660 If you say Y here, you will be able to update the microcode on
661 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
662 Pentium III, Pentium 4, Xeon etc. You will obviously need the
663 actual microcode binary data itself which is not shipped with the
666 For latest news and information on obtaining all the required
667 ingredients for this driver, check:
668 <http://www.urbanmyth.org/microcode/>.
670 To compile this driver as a module, choose M here: the
671 module will be called microcode.
673 config MICROCODE_OLD_INTERFACE
679 tristate "/dev/cpu/*/msr - Model-specific register support"
681 This device gives privileged processes access to the x86
682 Model-Specific Registers (MSRs). It is a character device with
683 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
684 MSR accesses are directed to a specific CPU on multi-processor
688 tristate "/dev/cpu/*/cpuid - CPU information support"
690 This device gives processes access to the x86 CPUID instruction to
691 be executed on a specific processor. It is a character device
692 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
696 prompt "High Memory Support"
697 default HIGHMEM4G if !X86_NUMAQ
698 default HIGHMEM64G if X86_NUMAQ
703 depends on !X86_NUMAQ
705 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
706 However, the address space of 32-bit x86 processors is only 4
707 Gigabytes large. That means that, if you have a large amount of
708 physical memory, not all of it can be "permanently mapped" by the
709 kernel. The physical memory that's not permanently mapped is called
712 If you are compiling a kernel which will never run on a machine with
713 more than 1 Gigabyte total physical RAM, answer "off" here (default
714 choice and suitable for most users). This will result in a "3GB/1GB"
715 split: 3GB are mapped so that each process sees a 3GB virtual memory
716 space and the remaining part of the 4GB virtual memory space is used
717 by the kernel to permanently map as much physical memory as
720 If the machine has between 1 and 4 Gigabytes physical RAM, then
723 If more than 4 Gigabytes is used then answer "64GB" here. This
724 selection turns Intel PAE (Physical Address Extension) mode on.
725 PAE implements 3-level paging on IA32 processors. PAE is fully
726 supported by Linux, PAE mode is implemented on all recent Intel
727 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
728 then the kernel will not boot on CPUs that don't support PAE!
730 The actual amount of total physical memory will either be
731 auto detected or can be forced by using a kernel command line option
732 such as "mem=256M". (Try "man bootparam" or see the documentation of
733 your boot loader (lilo or loadlin) about how to pass options to the
734 kernel at boot time.)
736 If unsure, say "off".
740 depends on !X86_NUMAQ
742 Select this if you have a 32-bit processor and between 1 and 4
743 gigabytes of physical RAM.
747 depends on !M386 && !M486
750 Select this if you have a 32-bit processor and more than 4
751 gigabytes of physical RAM.
756 depends on EXPERIMENTAL
757 prompt "Memory split" if EMBEDDED
761 Select the desired split between kernel and user memory.
763 If the address range available to the kernel is less than the
764 physical memory installed, the remaining memory will be available
765 as "high memory". Accessing high memory is a little more costly
766 than low memory, as it needs to be mapped into the kernel first.
767 Note that increasing the kernel address space limits the range
768 available to user programs, making the address space there
769 tighter. Selecting anything other than the default 3G/1G split
770 will also likely make your kernel incompatible with binary-only
773 If you are not absolutely sure what you are doing, leave this
777 bool "3G/1G user/kernel split"
778 config VMSPLIT_3G_OPT
780 bool "3G/1G user/kernel split (for full 1G low memory)"
782 bool "2G/2G user/kernel split"
783 config VMSPLIT_2G_OPT
785 bool "2G/2G user/kernel split (for full 2G low memory)"
787 bool "1G/3G user/kernel split"
792 default 0xB0000000 if VMSPLIT_3G_OPT
793 default 0x80000000 if VMSPLIT_2G
794 default 0x78000000 if VMSPLIT_2G_OPT
795 default 0x40000000 if VMSPLIT_1G
801 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
805 bool "PAE (Physical Address Extension) Support"
807 depends on X86_32 && !HIGHMEM4G
808 select RESOURCES_64BIT
810 PAE is required for NX support, and furthermore enables
811 larger swapspace support for non-overcommit purposes. It
812 has the cost of more pagetable lookup overhead, and also
813 consumes more pagetable space per process.
815 # Common NUMA Features
817 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
819 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL)
821 default y if (X86_NUMAQ || X86_SUMMIT)
823 Enable NUMA (Non Uniform Memory Access) support.
824 The kernel will try to allocate memory used by a CPU on the
825 local memory controller of the CPU and add some more
826 NUMA awareness to the kernel.
828 For i386 this is currently highly experimental and should be only
829 used for kernel development. It might also cause boot failures.
830 For x86_64 this is recommended on all multiprocessor Opteron systems.
831 If the system is EM64T, you should say N unless your system is
834 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
835 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
838 bool "Old style AMD Opteron NUMA detection"
839 depends on X86_64 && NUMA && PCI
842 Enable K8 NUMA node topology detection. You should say Y here if
843 you have a multi processor AMD K8 system. This uses an old
844 method to read the NUMA configuration directly from the builtin
845 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
846 instead, which also takes priority if both are compiled in.
848 config X86_64_ACPI_NUMA
849 bool "ACPI NUMA detection"
850 depends on X86_64 && NUMA && ACPI && PCI
854 Enable ACPI SRAT based node topology detection.
857 bool "NUMA emulation"
858 depends on X86_64 && NUMA
860 Enable NUMA emulation. A flat machine will be split
861 into virtual nodes when booted with "numa=fake=N", where N is the
862 number of nodes. This is only useful for debugging.
866 default "6" if X86_64
867 default "4" if X86_NUMAQ
869 depends on NEED_MULTIPLE_NODES
871 config HAVE_ARCH_BOOTMEM_NODE
873 depends on X86_32 && NUMA
876 config ARCH_HAVE_MEMORY_PRESENT
878 depends on X86_32 && DISCONTIGMEM
881 config NEED_NODE_MEMMAP_SIZE
883 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
886 config HAVE_ARCH_ALLOC_REMAP
888 depends on X86_32 && NUMA
891 config ARCH_FLATMEM_ENABLE
893 depends on (X86_32 && ARCH_SELECT_MEMORY_MODEL && X86_PC) || (X86_64 && !NUMA)
895 config ARCH_DISCONTIGMEM_ENABLE
899 config ARCH_DISCONTIGMEM_DEFAULT
903 config ARCH_SPARSEMEM_ENABLE
905 depends on NUMA || (EXPERIMENTAL && (X86_PC || X86_64))
906 select SPARSEMEM_STATIC if X86_32
907 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
909 config ARCH_SELECT_MEMORY_MODEL
911 depends on X86_32 && ARCH_SPARSEMEM_ENABLE
913 config ARCH_MEMORY_PROBE
915 depends on MEMORY_HOTPLUG
920 bool "Allocate 3rd-level pagetables from highmem"
921 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
923 The VM uses one page table entry for each page of physical memory.
924 For systems with a lot of RAM, this can be wasteful of precious
925 low memory. Setting this option will put user-space page table
926 entries in high memory.
928 config MATH_EMULATION
930 prompt "Math emulation" if X86_32
932 Linux can emulate a math coprocessor (used for floating point
933 operations) if you don't have one. 486DX and Pentium processors have
934 a math coprocessor built in, 486SX and 386 do not, unless you added
935 a 487DX or 387, respectively. (The messages during boot time can
936 give you some hints here ["man dmesg"].) Everyone needs either a
937 coprocessor or this emulation.
939 If you don't have a math coprocessor, you need to say Y here; if you
940 say Y here even though you have a coprocessor, the coprocessor will
941 be used nevertheless. (This behavior can be changed with the kernel
942 command line option "no387", which comes handy if your coprocessor
943 is broken. Try "man bootparam" or see the documentation of your boot
944 loader (lilo or loadlin) about how to pass options to the kernel at
945 boot time.) This means that it is a good idea to say Y here if you
946 intend to use this kernel on different machines.
948 More information about the internals of the Linux math coprocessor
949 emulation can be found in <file:arch/x86/math-emu/README>.
951 If you are not sure, say Y; apart from resulting in a 66 KB bigger
952 kernel, it won't hurt.
955 bool "MTRR (Memory Type Range Register) support"
957 On Intel P6 family processors (Pentium Pro, Pentium II and later)
958 the Memory Type Range Registers (MTRRs) may be used to control
959 processor access to memory ranges. This is most useful if you have
960 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
961 allows bus write transfers to be combined into a larger transfer
962 before bursting over the PCI/AGP bus. This can increase performance
963 of image write operations 2.5 times or more. Saying Y here creates a
964 /proc/mtrr file which may be used to manipulate your processor's
965 MTRRs. Typically the X server should use this.
967 This code has a reasonably generic interface so that similar
968 control registers on other processors can be easily supported
971 The Cyrix 6x86, 6x86MX and M II processors have Address Range
972 Registers (ARRs) which provide a similar functionality to MTRRs. For
973 these, the ARRs are used to emulate the MTRRs.
974 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
975 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
976 write-combining. All of these processors are supported by this code
977 and it makes sense to say Y here if you have one of them.
979 Saying Y here also fixes a problem with buggy SMP BIOSes which only
980 set the MTRRs for the boot CPU and not for the secondary CPUs. This
981 can lead to all sorts of problems, so it's good to say Y here.
983 You can safely say Y even if your machine doesn't have MTRRs, you'll
984 just add about 9 KB to your kernel.
986 See <file:Documentation/mtrr.txt> for more information.
989 bool "Boot from EFI support"
990 depends on X86_32 && ACPI
993 This enables the kernel to boot on EFI platforms using
994 system configuration information passed to it from the firmware.
995 This also enables the kernel to use any EFI runtime services that are
996 available (such as the EFI variable services).
998 This option is only useful on systems that have EFI firmware
999 and will result in a kernel image that is ~8k larger. In addition,
1000 you must use the latest ELILO loader available at
1001 <http://elilo.sourceforge.net> in order to take advantage of
1002 kernel initialization using EFI information (neither GRUB nor LILO know
1003 anything about EFI). However, even with this option, the resultant
1004 kernel should continue to boot on existing non-EFI platforms.
1007 bool "Enable kernel irq balancing"
1008 depends on X86_32 && SMP && X86_IO_APIC
1011 The default yes will allow the kernel to do irq load balancing.
1012 Saying no will keep the kernel from doing irq load balancing.
1014 # turning this on wastes a bunch of space.
1015 # Summit needs it only when NUMA is on
1018 depends on X86_32 && (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
1022 bool "Enable seccomp to safely compute untrusted bytecode"
1026 This kernel feature is useful for number crunching applications
1027 that may need to compute untrusted bytecode during their
1028 execution. By using pipes or other transports made available to
1029 the process as file descriptors supporting the read/write
1030 syscalls, it's possible to isolate those applications in
1031 their own address space using seccomp. Once seccomp is
1032 enabled via /proc/<pid>/seccomp, it cannot be disabled
1033 and the task is only allowed to execute a few safe syscalls
1034 defined by each seccomp mode.
1036 If unsure, say Y. Only embedded should say N here.
1038 config CC_STACKPROTECTOR
1039 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1040 depends on X86_64 && EXPERIMENTAL
1042 This option turns on the -fstack-protector GCC feature. This
1043 feature puts, at the beginning of critical functions, a canary
1044 value on the stack just before the return address, and validates
1045 the value just before actually returning. Stack based buffer
1046 overflows (that need to overwrite this return address) now also
1047 overwrite the canary, which gets detected and the attack is then
1048 neutralized via a kernel panic.
1050 This feature requires gcc version 4.2 or above, or a distribution
1051 gcc with the feature backported. Older versions are automatically
1052 detected and for those versions, this configuration option is ignored.
1054 config CC_STACKPROTECTOR_ALL
1055 bool "Use stack-protector for all functions"
1056 depends on CC_STACKPROTECTOR
1058 Normally, GCC only inserts the canary value protection for
1059 functions that use large-ish on-stack buffers. By enabling
1060 this option, GCC will be asked to do this for ALL functions.
1062 source kernel/Kconfig.hz
1065 bool "kexec system call"
1067 kexec is a system call that implements the ability to shutdown your
1068 current kernel, and to start another kernel. It is like a reboot
1069 but it is independent of the system firmware. And like a reboot
1070 you can start any kernel with it, not just Linux.
1072 The name comes from the similarity to the exec system call.
1074 It is an ongoing process to be certain the hardware in a machine
1075 is properly shutdown, so do not be surprised if this code does not
1076 initially work for you. It may help to enable device hotplugging
1077 support. As of this writing the exact hardware interface is
1078 strongly in flux, so no good recommendation can be made.
1081 bool "kernel crash dumps (EXPERIMENTAL)"
1082 depends on EXPERIMENTAL
1083 depends on X86_64 || (X86_32 && HIGHMEM)
1085 Generate crash dump after being started by kexec.
1086 This should be normally only set in special crash dump kernels
1087 which are loaded in the main kernel with kexec-tools into
1088 a specially reserved region and then later executed after
1089 a crash by kdump/kexec. The crash dump kernel must be compiled
1090 to a memory address not used by the main kernel or BIOS using
1091 PHYSICAL_START, or it must be built as a relocatable image
1092 (CONFIG_RELOCATABLE=y).
1093 For more details see Documentation/kdump/kdump.txt
1095 config PHYSICAL_START
1096 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1097 default "0x1000000" if X86_NUMAQ
1098 default "0x200000" if X86_64
1101 This gives the physical address where the kernel is loaded.
1103 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1104 bzImage will decompress itself to above physical address and
1105 run from there. Otherwise, bzImage will run from the address where
1106 it has been loaded by the boot loader and will ignore above physical
1109 In normal kdump cases one does not have to set/change this option
1110 as now bzImage can be compiled as a completely relocatable image
1111 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1112 address. This option is mainly useful for the folks who don't want
1113 to use a bzImage for capturing the crash dump and want to use a
1114 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1115 to be specifically compiled to run from a specific memory area
1116 (normally a reserved region) and this option comes handy.
1118 So if you are using bzImage for capturing the crash dump, leave
1119 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1120 Otherwise if you plan to use vmlinux for capturing the crash dump
1121 change this value to start of the reserved region (Typically 16MB
1122 0x1000000). In other words, it can be set based on the "X" value as
1123 specified in the "crashkernel=YM@XM" command line boot parameter
1124 passed to the panic-ed kernel. Typically this parameter is set as
1125 crashkernel=64M@16M. Please take a look at
1126 Documentation/kdump/kdump.txt for more details about crash dumps.
1128 Usage of bzImage for capturing the crash dump is recommended as
1129 one does not have to build two kernels. Same kernel can be used
1130 as production kernel and capture kernel. Above option should have
1131 gone away after relocatable bzImage support is introduced. But it
1132 is present because there are users out there who continue to use
1133 vmlinux for dump capture. This option should go away down the
1136 Don't change this unless you know what you are doing.
1139 bool "Build a relocatable kernel (EXPERIMENTAL)"
1140 depends on EXPERIMENTAL
1142 This builds a kernel image that retains relocation information
1143 so it can be loaded someplace besides the default 1MB.
1144 The relocations tend to make the kernel binary about 10% larger,
1145 but are discarded at runtime.
1147 One use is for the kexec on panic case where the recovery kernel
1148 must live at a different physical address than the primary
1151 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1152 it has been loaded at and the compile time physical address
1153 (CONFIG_PHYSICAL_START) is ignored.
1155 config PHYSICAL_ALIGN
1157 prompt "Alignment value to which kernel should be aligned" if X86_32
1158 default "0x100000" if X86_32
1159 default "0x200000" if X86_64
1160 range 0x2000 0x400000
1162 This value puts the alignment restrictions on physical address
1163 where kernel is loaded and run from. Kernel is compiled for an
1164 address which meets above alignment restriction.
1166 If bootloader loads the kernel at a non-aligned address and
1167 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1168 address aligned to above value and run from there.
1170 If bootloader loads the kernel at a non-aligned address and
1171 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1172 load address and decompress itself to the address it has been
1173 compiled for and run from there. The address for which kernel is
1174 compiled already meets above alignment restrictions. Hence the
1175 end result is that kernel runs from a physical address meeting
1176 above alignment restrictions.
1178 Don't change this unless you know what you are doing.
1181 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
1182 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
1184 Say Y here to experiment with turning CPUs off and on, and to
1185 enable suspend on SMP systems. CPUs can be controlled through
1186 /sys/devices/system/cpu.
1187 Say N if you want to disable CPU hotplug and don't need to
1191 bool "Compat VDSO support"
1195 Map the VDSO to the predictable old-style address too.
1197 Say N here if you are running a sufficiently recent glibc
1198 version (2.3.3 or later), to remove the high-mapped
1199 VDSO mapping and to exclusively use the randomized VDSO.
1205 config ARCH_ENABLE_MEMORY_HOTPLUG
1207 depends on X86_64 || (X86_32 && HIGHMEM)
1209 config MEMORY_HOTPLUG_RESERVE
1211 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
1213 config HAVE_ARCH_EARLY_PFN_TO_NID
1217 config OUT_OF_LINE_PFN_TO_PAGE
1219 depends on DISCONTIGMEM
1221 menu "Power management options"
1222 depends on !X86_VOYAGER
1224 config ARCH_HIBERNATION_HEADER
1226 depends on X86_64 && HIBERNATION
1229 source "kernel/power/Kconfig"
1231 source "drivers/acpi/Kconfig"
1234 tristate "APM (Advanced Power Management) BIOS support"
1235 depends on X86_32 && PM_SLEEP && !X86_VISWS
1237 APM is a BIOS specification for saving power using several different
1238 techniques. This is mostly useful for battery powered laptops with
1239 APM compliant BIOSes. If you say Y here, the system time will be
1240 reset after a RESUME operation, the /proc/apm device will provide
1241 battery status information, and user-space programs will receive
1242 notification of APM "events" (e.g. battery status change).
1244 If you select "Y" here, you can disable actual use of the APM
1245 BIOS by passing the "apm=off" option to the kernel at boot time.
1247 Note that the APM support is almost completely disabled for
1248 machines with more than one CPU.
1250 In order to use APM, you will need supporting software. For location
1251 and more information, read <file:Documentation/pm.txt> and the
1252 Battery Powered Linux mini-HOWTO, available from
1253 <http://www.tldp.org/docs.html#howto>.
1255 This driver does not spin down disk drives (see the hdparm(8)
1256 manpage ("man 8 hdparm") for that), and it doesn't turn off
1257 VESA-compliant "green" monitors.
1259 This driver does not support the TI 4000M TravelMate and the ACER
1260 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1261 desktop machines also don't have compliant BIOSes, and this driver
1262 may cause those machines to panic during the boot phase.
1264 Generally, if you don't have a battery in your machine, there isn't
1265 much point in using this driver and you should say N. If you get
1266 random kernel OOPSes or reboots that don't seem to be related to
1267 anything, try disabling/enabling this option (or disabling/enabling
1270 Some other things you should try when experiencing seemingly random,
1273 1) make sure that you have enough swap space and that it is
1275 2) pass the "no-hlt" option to the kernel
1276 3) switch on floating point emulation in the kernel and pass
1277 the "no387" option to the kernel
1278 4) pass the "floppy=nodma" option to the kernel
1279 5) pass the "mem=4M" option to the kernel (thereby disabling
1280 all but the first 4 MB of RAM)
1281 6) make sure that the CPU is not over clocked.
1282 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1283 8) disable the cache from your BIOS settings
1284 9) install a fan for the video card or exchange video RAM
1285 10) install a better fan for the CPU
1286 11) exchange RAM chips
1287 12) exchange the motherboard.
1289 To compile this driver as a module, choose M here: the
1290 module will be called apm.
1294 config APM_IGNORE_USER_SUSPEND
1295 bool "Ignore USER SUSPEND"
1297 This option will ignore USER SUSPEND requests. On machines with a
1298 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1299 series notebooks, it is necessary to say Y because of a BIOS bug.
1301 config APM_DO_ENABLE
1302 bool "Enable PM at boot time"
1304 Enable APM features at boot time. From page 36 of the APM BIOS
1305 specification: "When disabled, the APM BIOS does not automatically
1306 power manage devices, enter the Standby State, enter the Suspend
1307 State, or take power saving steps in response to CPU Idle calls."
1308 This driver will make CPU Idle calls when Linux is idle (unless this
1309 feature is turned off -- see "Do CPU IDLE calls", below). This
1310 should always save battery power, but more complicated APM features
1311 will be dependent on your BIOS implementation. You may need to turn
1312 this option off if your computer hangs at boot time when using APM
1313 support, or if it beeps continuously instead of suspending. Turn
1314 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1315 T400CDT. This is off by default since most machines do fine without
1319 bool "Make CPU Idle calls when idle"
1321 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1322 On some machines, this can activate improved power savings, such as
1323 a slowed CPU clock rate, when the machine is idle. These idle calls
1324 are made after the idle loop has run for some length of time (e.g.,
1325 333 mS). On some machines, this will cause a hang at boot time or
1326 whenever the CPU becomes idle. (On machines with more than one CPU,
1327 this option does nothing.)
1329 config APM_DISPLAY_BLANK
1330 bool "Enable console blanking using APM"
1332 Enable console blanking using the APM. Some laptops can use this to
1333 turn off the LCD backlight when the screen blanker of the Linux
1334 virtual console blanks the screen. Note that this is only used by
1335 the virtual console screen blanker, and won't turn off the backlight
1336 when using the X Window system. This also doesn't have anything to
1337 do with your VESA-compliant power-saving monitor. Further, this
1338 option doesn't work for all laptops -- it might not turn off your
1339 backlight at all, or it might print a lot of errors to the console,
1340 especially if you are using gpm.
1342 config APM_ALLOW_INTS
1343 bool "Allow interrupts during APM BIOS calls"
1345 Normally we disable external interrupts while we are making calls to
1346 the APM BIOS as a measure to lessen the effects of a badly behaving
1347 BIOS implementation. The BIOS should reenable interrupts if it
1348 needs to. Unfortunately, some BIOSes do not -- especially those in
1349 many of the newer IBM Thinkpads. If you experience hangs when you
1350 suspend, try setting this to Y. Otherwise, say N.
1352 config APM_REAL_MODE_POWER_OFF
1353 bool "Use real mode APM BIOS call to power off"
1355 Use real mode APM BIOS calls to switch off the computer. This is
1356 a work-around for a number of buggy BIOSes. Switch this option on if
1357 your computer crashes instead of powering off properly.
1361 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1363 source "drivers/cpuidle/Kconfig"
1368 menu "Bus options (PCI etc.)"
1371 bool "PCI support" if !X86_VISWS
1372 depends on !X86_VOYAGER
1373 default y if X86_VISWS
1374 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1376 Find out whether you have a PCI motherboard. PCI is the name of a
1377 bus system, i.e. the way the CPU talks to the other stuff inside
1378 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1379 VESA. If you have PCI, say Y, otherwise N.
1381 The PCI-HOWTO, available from
1382 <http://www.tldp.org/docs.html#howto>, contains valuable
1383 information about which PCI hardware does work under Linux and which
1387 prompt "PCI access mode"
1388 depends on X86_32 && PCI && !X86_VISWS
1391 On PCI systems, the BIOS can be used to detect the PCI devices and
1392 determine their configuration. However, some old PCI motherboards
1393 have BIOS bugs and may crash if this is done. Also, some embedded
1394 PCI-based systems don't have any BIOS at all. Linux can also try to
1395 detect the PCI hardware directly without using the BIOS.
1397 With this option, you can specify how Linux should detect the
1398 PCI devices. If you choose "BIOS", the BIOS will be used,
1399 if you choose "Direct", the BIOS won't be used, and if you
1400 choose "MMConfig", then PCI Express MMCONFIG will be used.
1401 If you choose "Any", the kernel will try MMCONFIG, then the
1402 direct access method and falls back to the BIOS if that doesn't
1403 work. If unsure, go with the default, which is "Any".
1408 config PCI_GOMMCONFIG
1421 depends on X86_32 && !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1424 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1427 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1432 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1441 bool "Support mmconfig PCI config space access"
1442 depends on X86_64 && PCI && ACPI
1445 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1446 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1448 DMA remapping (DMAR) devices support enables independent address
1449 translations for Direct Memory Access (DMA) from devices.
1450 These DMA remapping devices are reported via ACPI tables
1451 and include PCI device scope covered by these DMA
1455 bool "Support for Graphics workaround"
1459 Current Graphics drivers tend to use physical address
1460 for DMA and avoid using DMA APIs. Setting this config
1461 option permits the IOMMU driver to set a unity map for
1462 all the OS-visible memory. Hence the driver can continue
1463 to use physical addresses for DMA.
1465 config DMAR_FLOPPY_WA
1470 Floppy disk drivers are know to bypass DMA API calls
1471 thereby failing to work when IOMMU is enabled. This
1472 workaround will setup a 1:1 mapping for the first
1473 16M to make floppy (an ISA device) work.
1475 source "drivers/pci/pcie/Kconfig"
1477 source "drivers/pci/Kconfig"
1479 # x86_64 have no ISA slots, but do have ISA-style DMA.
1488 depends on !(X86_VOYAGER || X86_VISWS)
1490 Find out whether you have ISA slots on your motherboard. ISA is the
1491 name of a bus system, i.e. the way the CPU talks to the other stuff
1492 inside your box. Other bus systems are PCI, EISA, MicroChannel
1493 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1494 newer boards don't support it. If you have ISA, say Y, otherwise N.
1500 The Extended Industry Standard Architecture (EISA) bus was
1501 developed as an open alternative to the IBM MicroChannel bus.
1503 The EISA bus provided some of the features of the IBM MicroChannel
1504 bus while maintaining backward compatibility with cards made for
1505 the older ISA bus. The EISA bus saw limited use between 1988 and
1506 1995 when it was made obsolete by the PCI bus.
1508 Say Y here if you are building a kernel for an EISA-based machine.
1512 source "drivers/eisa/Kconfig"
1515 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1516 default y if X86_VOYAGER
1518 MicroChannel Architecture is found in some IBM PS/2 machines and
1519 laptops. It is a bus system similar to PCI or ISA. See
1520 <file:Documentation/mca.txt> (and especially the web page given
1521 there) before attempting to build an MCA bus kernel.
1523 source "drivers/mca/Kconfig"
1526 tristate "NatSemi SCx200 support"
1527 depends on !X86_VOYAGER
1529 This provides basic support for National Semiconductor's
1530 (now AMD's) Geode processors. The driver probes for the
1531 PCI-IDs of several on-chip devices, so its a good dependency
1532 for other scx200_* drivers.
1534 If compiled as a module, the driver is named scx200.
1536 config SCx200HR_TIMER
1537 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1538 depends on SCx200 && GENERIC_TIME
1541 This driver provides a clocksource built upon the on-chip
1542 27MHz high-resolution timer. Its also a workaround for
1543 NSC Geode SC-1100's buggy TSC, which loses time when the
1544 processor goes idle (as is done by the scheduler). The
1545 other workaround is idle=poll boot option.
1547 config GEODE_MFGPT_TIMER
1548 bool "Geode Multi-Function General Purpose Timer (MFGPT) events"
1549 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1552 This driver provides a clock event source based on the MFGPT
1553 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1554 MFGPTs have a better resolution and max interval than the
1555 generic PIT, and are suitable for use as high-res timers.
1561 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1563 source "drivers/pcmcia/Kconfig"
1565 source "drivers/pci/hotplug/Kconfig"
1570 menu "Executable file formats / Emulations"
1572 source "fs/Kconfig.binfmt"
1574 config IA32_EMULATION
1575 bool "IA32 Emulation"
1578 Include code to run 32-bit programs under a 64-bit kernel. You should
1579 likely turn this on, unless you're 100% sure that you don't have any
1580 32-bit programs left.
1583 tristate "IA32 a.out support"
1584 depends on IA32_EMULATION
1586 Support old a.out binaries in the 32bit emulation.
1590 depends on IA32_EMULATION
1593 config COMPAT_FOR_U64_ALIGNMENT
1597 config SYSVIPC_COMPAT
1599 depends on X86_64 && COMPAT && SYSVIPC
1605 source "net/Kconfig"
1607 source "drivers/Kconfig"
1609 source "drivers/firmware/Kconfig"
1613 source "kernel/Kconfig.instrumentation"
1615 source "arch/x86/Kconfig.debug"
1617 source "security/Kconfig"
1619 source "crypto/Kconfig"
1621 source "lib/Kconfig"
projects / linux-2.6 / blob