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
115 config ARCH_SUPPORTS_OPROFILE
124 config ARCH_POPULATES_NODE_MAP
131 # Use the generic interrupt handling code in kernel/irq/:
132 config GENERIC_HARDIRQS
136 config GENERIC_IRQ_PROBE
140 config GENERIC_PENDING_IRQ
142 depends on GENERIC_HARDIRQS && SMP
147 depends on X86_32 && SMP && !X86_VOYAGER
153 depends on (X86_32 && !(X86_VISWS || X86_VOYAGER)) || (X86_64 && !MK8)
156 config X86_BIOS_REBOOT
158 depends on X86_32 && !(X86_VISWS || X86_VOYAGER)
161 config X86_TRAMPOLINE
163 depends on X86_SMP || (X86_VOYAGER && SMP)
168 source "init/Kconfig"
170 menu "Processor type and features"
172 source "kernel/time/Kconfig"
175 bool "Symmetric multi-processing support"
177 This enables support for systems with more than one CPU. If you have
178 a system with only one CPU, like most personal computers, say N. If
179 you have a system with more than one CPU, say Y.
181 If you say N here, the kernel will run on single and multiprocessor
182 machines, but will use only one CPU of a multiprocessor machine. If
183 you say Y here, the kernel will run on many, but not all,
184 singleprocessor machines. On a singleprocessor machine, the kernel
185 will run faster if you say N here.
187 Note that if you say Y here and choose architecture "586" or
188 "Pentium" under "Processor family", the kernel will not work on 486
189 architectures. Similarly, multiprocessor kernels for the "PPro"
190 architecture may not work on all Pentium based boards.
192 People using multiprocessor machines who say Y here should also say
193 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
194 Management" code will be disabled if you say Y here.
196 See also the <file:Documentation/smp.txt>,
197 <file:Documentation/i386/IO-APIC.txt>,
198 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
199 <http://www.tldp.org/docs.html#howto>.
201 If you don't know what to do here, say N.
204 prompt "Subarchitecture Type"
210 Choose this option if your computer is a standard PC or compatible.
216 Select this for an AMD Elan processor.
218 Do not use this option for K6/Athlon/Opteron processors!
220 If unsure, choose "PC-compatible" instead.
225 select SMP if !BROKEN
227 Voyager is an MCA-based 32-way capable SMP architecture proprietary
228 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
232 If you do not specifically know you have a Voyager based machine,
233 say N here, otherwise the kernel you build will not be bootable.
236 bool "NUMAQ (IBM/Sequent)"
241 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
242 multiquad box. This changes the way that processors are bootstrapped,
243 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
244 You will need a new lynxer.elf file to flash your firmware with - send
245 email to <Martin.Bligh@us.ibm.com>.
248 bool "Summit/EXA (IBM x440)"
249 depends on X86_32 && SMP
251 This option is needed for IBM systems that use the Summit/EXA chipset.
252 In particular, it is needed for the x440.
254 If you don't have one of these computers, you should say N here.
255 If you want to build a NUMA kernel, you must select ACPI.
258 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
259 depends on X86_32 && SMP
261 This option is needed for the systems that have more than 8 CPUs
262 and if the system is not of any sub-arch type above.
264 If you don't have such a system, you should say N here.
267 bool "SGI 320/540 (Visual Workstation)"
270 The SGI Visual Workstation series is an IA32-based workstation
271 based on SGI systems chips with some legacy PC hardware attached.
273 Say Y here to create a kernel to run on the SGI 320 or 540.
275 A kernel compiled for the Visual Workstation will not run on PCs
276 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
278 config X86_GENERICARCH
279 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
282 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
283 It is intended for a generic binary kernel.
284 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
287 bool "Support for Unisys ES7000 IA32 series"
288 depends on X86_32 && SMP
290 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
291 supposed to run on an IA32-based Unisys ES7000 system.
292 Only choose this option if you have such a system, otherwise you
296 bool "Support for ScaleMP vSMP"
297 depends on X86_64 && PCI
299 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
300 supposed to run on these EM64T-based machines. Only choose this option
301 if you have one of these machines.
305 config SCHED_NO_NO_OMIT_FRAME_POINTER
306 bool "Single-depth WCHAN output"
310 Calculate simpler /proc/<PID>/wchan values. If this option
311 is disabled then wchan values will recurse back to the
312 caller function. This provides more accurate wchan values,
313 at the expense of slightly more scheduling overhead.
315 If in doubt, say "Y".
319 depends on X86_32 && !(X86_VISWS || X86_VOYAGER)
321 This changes the kernel so it can modify itself when it is run
322 under a hypervisor, potentially improving performance significantly
323 over full virtualization. However, when run without a hypervisor
324 the kernel is theoretically slower and slightly larger.
326 menuconfig PARAVIRT_GUEST
327 bool "Paravirtualized guest support"
330 Say Y here to get to see options related to running Linux under
331 various hypervisors. This option alone does not add any kernel code.
333 If you say N, all options in this submenu will be skipped and disabled.
337 source "arch/x86/xen/Kconfig"
340 bool "VMI Guest support"
342 depends on !(X86_VISWS || X86_VOYAGER)
344 VMI provides a paravirtualized interface to the VMware ESX server
345 (it could be used by other hypervisors in theory too, but is not
346 at the moment), by linking the kernel to a GPL-ed ROM module
347 provided by the hypervisor.
349 source "arch/x86/lguest/Kconfig"
356 depends on X86_32 && ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
359 config HAVE_ARCH_PARSE_SRAT
364 config X86_SUMMIT_NUMA
367 depends on X86_32 && NUMA && (X86_SUMMIT || X86_GENERICARCH)
369 config X86_CYCLONE_TIMER
372 depends on X86_32 && X86_SUMMIT || X86_GENERICARCH
374 config ES7000_CLUSTERED_APIC
377 depends on SMP && X86_ES7000 && MPENTIUMIII
379 source "arch/x86/Kconfig.cpu"
383 prompt "HPET Timer Support" if X86_32
386 Use the IA-PC HPET (High Precision Event Timer) to manage
387 time in preference to the PIT and RTC, if a HPET is
389 HPET is the next generation timer replacing legacy 8254s.
390 The HPET provides a stable time base on SMP
391 systems, unlike the TSC, but it is more expensive to access,
392 as it is off-chip. You can find the HPET spec at
393 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
395 You can safely choose Y here. However, HPET will only be
396 activated if the platform and the BIOS support this feature.
397 Otherwise the 8254 will be used for timing services.
399 Choose N to continue using the legacy 8254 timer.
401 config HPET_EMULATE_RTC
403 depends on HPET_TIMER && RTC=y
406 # Mark as embedded because too many people got it wrong.
407 # The code disables itself when not needed.
409 bool "GART IOMMU support" if EMBEDDED
413 depends on X86_64 && PCI
415 Support for full DMA access of devices with 32bit memory access only
416 on systems with more than 3GB. This is usually needed for USB,
417 sound, many IDE/SATA chipsets and some other devices.
418 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
419 based hardware IOMMU and a software bounce buffer based IOMMU used
420 on Intel systems and as fallback.
421 The code is only active when needed (enough memory and limited
422 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
426 bool "IBM Calgary IOMMU support"
428 depends on X86_64 && PCI && EXPERIMENTAL
430 Support for hardware IOMMUs in IBM's xSeries x366 and x460
431 systems. Needed to run systems with more than 3GB of memory
432 properly with 32-bit PCI devices that do not support DAC
433 (Double Address Cycle). Calgary also supports bus level
434 isolation, where all DMAs pass through the IOMMU. This
435 prevents them from going anywhere except their intended
436 destination. This catches hard-to-find kernel bugs and
437 mis-behaving drivers and devices that do not use the DMA-API
438 properly to set up their DMA buffers. The IOMMU can be
439 turned off at boot time with the iommu=off parameter.
440 Normally the kernel will make the right choice by itself.
443 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
444 bool "Should Calgary be enabled by default?"
446 depends on CALGARY_IOMMU
448 Should Calgary be enabled by default? if you choose 'y', Calgary
449 will be used (if it exists). If you choose 'n', Calgary will not be
450 used even if it exists. If you choose 'n' and would like to use
451 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
454 # need this always selected by IOMMU for the VIA workaround
458 Support for software bounce buffers used on x86-64 systems
459 which don't have a hardware IOMMU (e.g. the current generation
460 of Intel's x86-64 CPUs). Using this PCI devices which can only
461 access 32-bits of memory can be used on systems with more than
462 3 GB of memory. If unsure, say Y.
466 int "Maximum number of CPUs (2-255)"
469 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
472 This allows you to specify the maximum number of CPUs which this
473 kernel will support. The maximum supported value is 255 and the
474 minimum value which makes sense is 2.
476 This is purely to save memory - each supported CPU adds
477 approximately eight kilobytes to the kernel image.
480 bool "SMT (Hyperthreading) scheduler support"
481 depends on (X86_64 && SMP) || (X86_32 && X86_HT)
483 SMT scheduler support improves the CPU scheduler's decision making
484 when dealing with Intel Pentium 4 chips with HyperThreading at a
485 cost of slightly increased overhead in some places. If unsure say
489 bool "Multi-core scheduler support"
490 depends on (X86_64 && SMP) || (X86_32 && X86_HT)
493 Multi-core scheduler support improves the CPU scheduler's decision
494 making when dealing with multi-core CPU chips at a cost of slightly
495 increased overhead in some places. If unsure say N here.
497 source "kernel/Kconfig.preempt"
500 bool "Local APIC support on uniprocessors"
501 depends on X86_32 && !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
503 A local APIC (Advanced Programmable Interrupt Controller) is an
504 integrated interrupt controller in the CPU. If you have a single-CPU
505 system which has a processor with a local APIC, you can say Y here to
506 enable and use it. If you say Y here even though your machine doesn't
507 have a local APIC, then the kernel will still run with no slowdown at
508 all. The local APIC supports CPU-generated self-interrupts (timer,
509 performance counters), and the NMI watchdog which detects hard
513 bool "IO-APIC support on uniprocessors"
514 depends on X86_UP_APIC
516 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
517 SMP-capable replacement for PC-style interrupt controllers. Most
518 SMP systems and many recent uniprocessor systems have one.
520 If you have a single-CPU system with an IO-APIC, you can say Y here
521 to use it. If you say Y here even though your machine doesn't have
522 an IO-APIC, then the kernel will still run with no slowdown at all.
524 config X86_LOCAL_APIC
526 depends on X86_64 || (X86_32 && (X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH))
531 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH))
534 config X86_VISWS_APIC
536 depends on X86_32 && X86_VISWS
540 bool "Machine Check Exception"
541 depends on !X86_VOYAGER
543 Machine Check Exception support allows the processor to notify the
544 kernel if it detects a problem (e.g. overheating, component failure).
545 The action the kernel takes depends on the severity of the problem,
546 ranging from a warning message on the console, to halting the machine.
547 Your processor must be a Pentium or newer to support this - check the
548 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
549 have a design flaw which leads to false MCE events - hence MCE is
550 disabled on all P5 processors, unless explicitly enabled with "mce"
551 as a boot argument. Similarly, if MCE is built in and creates a
552 problem on some new non-standard machine, you can boot with "nomce"
553 to disable it. MCE support simply ignores non-MCE processors like
554 the 386 and 486, so nearly everyone can say Y here.
557 bool "Intel MCE features"
558 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
561 Additional support for intel specific MCE features such as
565 bool "AMD MCE features"
566 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
569 Additional support for AMD specific MCE features such as
570 the DRAM Error Threshold.
572 config X86_MCE_NONFATAL
573 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
574 depends on X86_32 && X86_MCE
576 Enabling this feature starts a timer that triggers every 5 seconds which
577 will look at the machine check registers to see if anything happened.
578 Non-fatal problems automatically get corrected (but still logged).
579 Disable this if you don't want to see these messages.
580 Seeing the messages this option prints out may be indicative of dying
581 or out-of-spec (ie, overclocked) hardware.
582 This option only does something on certain CPUs.
583 (AMD Athlon/Duron and Intel Pentium 4)
585 config X86_MCE_P4THERMAL
586 bool "check for P4 thermal throttling interrupt."
587 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
589 Enabling this feature will cause a message to be printed when the P4
590 enters thermal throttling.
593 bool "Enable VM86 support" if EMBEDDED
597 This option is required by programs like DOSEMU to run 16-bit legacy
598 code on X86 processors. It also may be needed by software like
599 XFree86 to initialize some video cards via BIOS. Disabling this
600 option saves about 6k.
603 tristate "Toshiba Laptop support"
606 This adds a driver to safely access the System Management Mode of
607 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
608 not work on models with a Phoenix BIOS. The System Management Mode
609 is used to set the BIOS and power saving options on Toshiba portables.
611 For information on utilities to make use of this driver see the
612 Toshiba Linux utilities web site at:
613 <http://www.buzzard.org.uk/toshiba/>.
615 Say Y if you intend to run this kernel on a Toshiba portable.
619 tristate "Dell laptop support"
622 This adds a driver to safely access the System Management Mode
623 of the CPU on the Dell Inspiron 8000. The System Management Mode
624 is used to read cpu temperature and cooling fan status and to
625 control the fans on the I8K portables.
627 This driver has been tested only on the Inspiron 8000 but it may
628 also work with other Dell laptops. You can force loading on other
629 models by passing the parameter `force=1' to the module. Use at
632 For information on utilities to make use of this driver see the
633 I8K Linux utilities web site at:
634 <http://people.debian.org/~dz/i8k/>
636 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
639 config X86_REBOOTFIXUPS
640 bool "Enable X86 board specific fixups for reboot"
641 depends on X86_32 && X86
644 This enables chipset and/or board specific fixups to be done
645 in order to get reboot to work correctly. This is only needed on
646 some combinations of hardware and BIOS. The symptom, for which
647 this config is intended, is when reboot ends with a stalled/hung
650 Currently, the only fixup is for the Geode machines using
651 CS5530A and CS5536 chipsets.
653 Say Y if you want to enable the fixup. Currently, it's safe to
654 enable this option even if you don't need it.
658 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
661 If you say Y here, you will be able to update the microcode on
662 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
663 Pentium III, Pentium 4, Xeon etc. You will obviously need the
664 actual microcode binary data itself which is not shipped with the
667 For latest news and information on obtaining all the required
668 ingredients for this driver, check:
669 <http://www.urbanmyth.org/microcode/>.
671 To compile this driver as a module, choose M here: the
672 module will be called microcode.
674 config MICROCODE_OLD_INTERFACE
680 tristate "/dev/cpu/*/msr - Model-specific register support"
682 This device gives privileged processes access to the x86
683 Model-Specific Registers (MSRs). It is a character device with
684 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
685 MSR accesses are directed to a specific CPU on multi-processor
689 tristate "/dev/cpu/*/cpuid - CPU information support"
691 This device gives processes access to the x86 CPUID instruction to
692 be executed on a specific processor. It is a character device
693 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
697 prompt "High Memory Support"
698 default HIGHMEM4G if !X86_NUMAQ
699 default HIGHMEM64G if X86_NUMAQ
704 depends on !X86_NUMAQ
706 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
707 However, the address space of 32-bit x86 processors is only 4
708 Gigabytes large. That means that, if you have a large amount of
709 physical memory, not all of it can be "permanently mapped" by the
710 kernel. The physical memory that's not permanently mapped is called
713 If you are compiling a kernel which will never run on a machine with
714 more than 1 Gigabyte total physical RAM, answer "off" here (default
715 choice and suitable for most users). This will result in a "3GB/1GB"
716 split: 3GB are mapped so that each process sees a 3GB virtual memory
717 space and the remaining part of the 4GB virtual memory space is used
718 by the kernel to permanently map as much physical memory as
721 If the machine has between 1 and 4 Gigabytes physical RAM, then
724 If more than 4 Gigabytes is used then answer "64GB" here. This
725 selection turns Intel PAE (Physical Address Extension) mode on.
726 PAE implements 3-level paging on IA32 processors. PAE is fully
727 supported by Linux, PAE mode is implemented on all recent Intel
728 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
729 then the kernel will not boot on CPUs that don't support PAE!
731 The actual amount of total physical memory will either be
732 auto detected or can be forced by using a kernel command line option
733 such as "mem=256M". (Try "man bootparam" or see the documentation of
734 your boot loader (lilo or loadlin) about how to pass options to the
735 kernel at boot time.)
737 If unsure, say "off".
741 depends on !X86_NUMAQ
743 Select this if you have a 32-bit processor and between 1 and 4
744 gigabytes of physical RAM.
748 depends on !M386 && !M486
751 Select this if you have a 32-bit processor and more than 4
752 gigabytes of physical RAM.
757 depends on EXPERIMENTAL
758 prompt "Memory split" if EMBEDDED
762 Select the desired split between kernel and user memory.
764 If the address range available to the kernel is less than the
765 physical memory installed, the remaining memory will be available
766 as "high memory". Accessing high memory is a little more costly
767 than low memory, as it needs to be mapped into the kernel first.
768 Note that increasing the kernel address space limits the range
769 available to user programs, making the address space there
770 tighter. Selecting anything other than the default 3G/1G split
771 will also likely make your kernel incompatible with binary-only
774 If you are not absolutely sure what you are doing, leave this
778 bool "3G/1G user/kernel split"
779 config VMSPLIT_3G_OPT
781 bool "3G/1G user/kernel split (for full 1G low memory)"
783 bool "2G/2G user/kernel split"
784 config VMSPLIT_2G_OPT
786 bool "2G/2G user/kernel split (for full 2G low memory)"
788 bool "1G/3G user/kernel split"
793 default 0xB0000000 if VMSPLIT_3G_OPT
794 default 0x80000000 if VMSPLIT_2G
795 default 0x78000000 if VMSPLIT_2G_OPT
796 default 0x40000000 if VMSPLIT_1G
802 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
806 bool "PAE (Physical Address Extension) Support"
808 depends on X86_32 && !HIGHMEM4G
809 select RESOURCES_64BIT
811 PAE is required for NX support, and furthermore enables
812 larger swapspace support for non-overcommit purposes. It
813 has the cost of more pagetable lookup overhead, and also
814 consumes more pagetable space per process.
816 # Common NUMA Features
818 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
820 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL)
822 default y if (X86_NUMAQ || X86_SUMMIT)
824 Enable NUMA (Non Uniform Memory Access) support.
825 The kernel will try to allocate memory used by a CPU on the
826 local memory controller of the CPU and add some more
827 NUMA awareness to the kernel.
829 For i386 this is currently highly experimental and should be only
830 used for kernel development. It might also cause boot failures.
831 For x86_64 this is recommended on all multiprocessor Opteron systems.
832 If the system is EM64T, you should say N unless your system is
835 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
836 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
839 bool "Old style AMD Opteron NUMA detection"
840 depends on X86_64 && NUMA && PCI
843 Enable K8 NUMA node topology detection. You should say Y here if
844 you have a multi processor AMD K8 system. This uses an old
845 method to read the NUMA configuration directly from the builtin
846 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
847 instead, which also takes priority if both are compiled in.
849 config X86_64_ACPI_NUMA
850 bool "ACPI NUMA detection"
851 depends on X86_64 && NUMA && ACPI && PCI
855 Enable ACPI SRAT based node topology detection.
858 bool "NUMA emulation"
859 depends on X86_64 && NUMA
861 Enable NUMA emulation. A flat machine will be split
862 into virtual nodes when booted with "numa=fake=N", where N is the
863 number of nodes. This is only useful for debugging.
867 default "6" if X86_64
868 default "4" if X86_NUMAQ
870 depends on NEED_MULTIPLE_NODES
872 config HAVE_ARCH_BOOTMEM_NODE
874 depends on X86_32 && NUMA
877 config ARCH_HAVE_MEMORY_PRESENT
879 depends on X86_32 && DISCONTIGMEM
882 config NEED_NODE_MEMMAP_SIZE
884 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
887 config HAVE_ARCH_ALLOC_REMAP
889 depends on X86_32 && NUMA
892 config ARCH_FLATMEM_ENABLE
894 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && X86_PC
896 config ARCH_DISCONTIGMEM_ENABLE
898 depends on NUMA && X86_32
900 config ARCH_DISCONTIGMEM_DEFAULT
902 depends on NUMA && X86_32
904 config ARCH_SPARSEMEM_DEFAULT
908 config ARCH_SPARSEMEM_ENABLE
910 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC)
911 select SPARSEMEM_STATIC if X86_32
912 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
914 config ARCH_SELECT_MEMORY_MODEL
916 depends on ARCH_SPARSEMEM_ENABLE
918 config ARCH_MEMORY_PROBE
920 depends on MEMORY_HOTPLUG
925 bool "Allocate 3rd-level pagetables from highmem"
926 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
928 The VM uses one page table entry for each page of physical memory.
929 For systems with a lot of RAM, this can be wasteful of precious
930 low memory. Setting this option will put user-space page table
931 entries in high memory.
933 config MATH_EMULATION
935 prompt "Math emulation" if X86_32
937 Linux can emulate a math coprocessor (used for floating point
938 operations) if you don't have one. 486DX and Pentium processors have
939 a math coprocessor built in, 486SX and 386 do not, unless you added
940 a 487DX or 387, respectively. (The messages during boot time can
941 give you some hints here ["man dmesg"].) Everyone needs either a
942 coprocessor or this emulation.
944 If you don't have a math coprocessor, you need to say Y here; if you
945 say Y here even though you have a coprocessor, the coprocessor will
946 be used nevertheless. (This behavior can be changed with the kernel
947 command line option "no387", which comes handy if your coprocessor
948 is broken. Try "man bootparam" or see the documentation of your boot
949 loader (lilo or loadlin) about how to pass options to the kernel at
950 boot time.) This means that it is a good idea to say Y here if you
951 intend to use this kernel on different machines.
953 More information about the internals of the Linux math coprocessor
954 emulation can be found in <file:arch/x86/math-emu/README>.
956 If you are not sure, say Y; apart from resulting in a 66 KB bigger
957 kernel, it won't hurt.
960 bool "MTRR (Memory Type Range Register) support"
962 On Intel P6 family processors (Pentium Pro, Pentium II and later)
963 the Memory Type Range Registers (MTRRs) may be used to control
964 processor access to memory ranges. This is most useful if you have
965 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
966 allows bus write transfers to be combined into a larger transfer
967 before bursting over the PCI/AGP bus. This can increase performance
968 of image write operations 2.5 times or more. Saying Y here creates a
969 /proc/mtrr file which may be used to manipulate your processor's
970 MTRRs. Typically the X server should use this.
972 This code has a reasonably generic interface so that similar
973 control registers on other processors can be easily supported
976 The Cyrix 6x86, 6x86MX and M II processors have Address Range
977 Registers (ARRs) which provide a similar functionality to MTRRs. For
978 these, the ARRs are used to emulate the MTRRs.
979 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
980 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
981 write-combining. All of these processors are supported by this code
982 and it makes sense to say Y here if you have one of them.
984 Saying Y here also fixes a problem with buggy SMP BIOSes which only
985 set the MTRRs for the boot CPU and not for the secondary CPUs. This
986 can lead to all sorts of problems, so it's good to say Y here.
988 You can safely say Y even if your machine doesn't have MTRRs, you'll
989 just add about 9 KB to your kernel.
991 See <file:Documentation/mtrr.txt> for more information.
994 bool "Boot from EFI support"
995 depends on X86_32 && ACPI
998 This enables the kernel to boot on EFI platforms using
999 system configuration information passed to it from the firmware.
1000 This also enables the kernel to use any EFI runtime services that are
1001 available (such as the EFI variable services).
1003 This option is only useful on systems that have EFI firmware
1004 and will result in a kernel image that is ~8k larger. In addition,
1005 you must use the latest ELILO loader available at
1006 <http://elilo.sourceforge.net> in order to take advantage of
1007 kernel initialization using EFI information (neither GRUB nor LILO know
1008 anything about EFI). However, even with this option, the resultant
1009 kernel should continue to boot on existing non-EFI platforms.
1012 bool "Enable kernel irq balancing"
1013 depends on X86_32 && SMP && X86_IO_APIC
1016 The default yes will allow the kernel to do irq load balancing.
1017 Saying no will keep the kernel from doing irq load balancing.
1019 # turning this on wastes a bunch of space.
1020 # Summit needs it only when NUMA is on
1023 depends on X86_32 && (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
1027 bool "Enable seccomp to safely compute untrusted bytecode"
1031 This kernel feature is useful for number crunching applications
1032 that may need to compute untrusted bytecode during their
1033 execution. By using pipes or other transports made available to
1034 the process as file descriptors supporting the read/write
1035 syscalls, it's possible to isolate those applications in
1036 their own address space using seccomp. Once seccomp is
1037 enabled via /proc/<pid>/seccomp, it cannot be disabled
1038 and the task is only allowed to execute a few safe syscalls
1039 defined by each seccomp mode.
1041 If unsure, say Y. Only embedded should say N here.
1043 config CC_STACKPROTECTOR
1044 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1045 depends on X86_64 && EXPERIMENTAL
1047 This option turns on the -fstack-protector GCC feature. This
1048 feature puts, at the beginning of critical functions, a canary
1049 value on the stack just before the return address, and validates
1050 the value just before actually returning. Stack based buffer
1051 overflows (that need to overwrite this return address) now also
1052 overwrite the canary, which gets detected and the attack is then
1053 neutralized via a kernel panic.
1055 This feature requires gcc version 4.2 or above, or a distribution
1056 gcc with the feature backported. Older versions are automatically
1057 detected and for those versions, this configuration option is ignored.
1059 config CC_STACKPROTECTOR_ALL
1060 bool "Use stack-protector for all functions"
1061 depends on CC_STACKPROTECTOR
1063 Normally, GCC only inserts the canary value protection for
1064 functions that use large-ish on-stack buffers. By enabling
1065 this option, GCC will be asked to do this for ALL functions.
1067 source kernel/Kconfig.hz
1070 bool "kexec system call"
1072 kexec is a system call that implements the ability to shutdown your
1073 current kernel, and to start another kernel. It is like a reboot
1074 but it is independent of the system firmware. And like a reboot
1075 you can start any kernel with it, not just Linux.
1077 The name comes from the similarity to the exec system call.
1079 It is an ongoing process to be certain the hardware in a machine
1080 is properly shutdown, so do not be surprised if this code does not
1081 initially work for you. It may help to enable device hotplugging
1082 support. As of this writing the exact hardware interface is
1083 strongly in flux, so no good recommendation can be made.
1086 bool "kernel crash dumps (EXPERIMENTAL)"
1087 depends on EXPERIMENTAL
1088 depends on X86_64 || (X86_32 && HIGHMEM)
1090 Generate crash dump after being started by kexec.
1091 This should be normally only set in special crash dump kernels
1092 which are loaded in the main kernel with kexec-tools into
1093 a specially reserved region and then later executed after
1094 a crash by kdump/kexec. The crash dump kernel must be compiled
1095 to a memory address not used by the main kernel or BIOS using
1096 PHYSICAL_START, or it must be built as a relocatable image
1097 (CONFIG_RELOCATABLE=y).
1098 For more details see Documentation/kdump/kdump.txt
1100 config PHYSICAL_START
1101 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1102 default "0x1000000" if X86_NUMAQ
1103 default "0x200000" if X86_64
1106 This gives the physical address where the kernel is loaded.
1108 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1109 bzImage will decompress itself to above physical address and
1110 run from there. Otherwise, bzImage will run from the address where
1111 it has been loaded by the boot loader and will ignore above physical
1114 In normal kdump cases one does not have to set/change this option
1115 as now bzImage can be compiled as a completely relocatable image
1116 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1117 address. This option is mainly useful for the folks who don't want
1118 to use a bzImage for capturing the crash dump and want to use a
1119 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1120 to be specifically compiled to run from a specific memory area
1121 (normally a reserved region) and this option comes handy.
1123 So if you are using bzImage for capturing the crash dump, leave
1124 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1125 Otherwise if you plan to use vmlinux for capturing the crash dump
1126 change this value to start of the reserved region (Typically 16MB
1127 0x1000000). In other words, it can be set based on the "X" value as
1128 specified in the "crashkernel=YM@XM" command line boot parameter
1129 passed to the panic-ed kernel. Typically this parameter is set as
1130 crashkernel=64M@16M. Please take a look at
1131 Documentation/kdump/kdump.txt for more details about crash dumps.
1133 Usage of bzImage for capturing the crash dump is recommended as
1134 one does not have to build two kernels. Same kernel can be used
1135 as production kernel and capture kernel. Above option should have
1136 gone away after relocatable bzImage support is introduced. But it
1137 is present because there are users out there who continue to use
1138 vmlinux for dump capture. This option should go away down the
1141 Don't change this unless you know what you are doing.
1144 bool "Build a relocatable kernel (EXPERIMENTAL)"
1145 depends on EXPERIMENTAL
1147 This builds a kernel image that retains relocation information
1148 so it can be loaded someplace besides the default 1MB.
1149 The relocations tend to make the kernel binary about 10% larger,
1150 but are discarded at runtime.
1152 One use is for the kexec on panic case where the recovery kernel
1153 must live at a different physical address than the primary
1156 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1157 it has been loaded at and the compile time physical address
1158 (CONFIG_PHYSICAL_START) is ignored.
1160 config PHYSICAL_ALIGN
1162 prompt "Alignment value to which kernel should be aligned" if X86_32
1163 default "0x100000" if X86_32
1164 default "0x200000" if X86_64
1165 range 0x2000 0x400000
1167 This value puts the alignment restrictions on physical address
1168 where kernel is loaded and run from. Kernel is compiled for an
1169 address which meets above alignment restriction.
1171 If bootloader loads the kernel at a non-aligned address and
1172 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1173 address aligned to above value and run from there.
1175 If bootloader loads the kernel at a non-aligned address and
1176 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1177 load address and decompress itself to the address it has been
1178 compiled for and run from there. The address for which kernel is
1179 compiled already meets above alignment restrictions. Hence the
1180 end result is that kernel runs from a physical address meeting
1181 above alignment restrictions.
1183 Don't change this unless you know what you are doing.
1186 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
1187 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
1189 Say Y here to experiment with turning CPUs off and on, and to
1190 enable suspend on SMP systems. CPUs can be controlled through
1191 /sys/devices/system/cpu.
1192 Say N if you want to disable CPU hotplug and don't need to
1196 bool "Compat VDSO support"
1198 depends on X86_32 || IA32_EMULATION
1200 Map the 32-bit VDSO to the predictable old-style address too.
1202 Say N here if you are running a sufficiently recent glibc
1203 version (2.3.3 or later), to remove the high-mapped
1204 VDSO mapping and to exclusively use the randomized VDSO.
1210 config ARCH_ENABLE_MEMORY_HOTPLUG
1212 depends on X86_64 || (X86_32 && HIGHMEM)
1214 config HAVE_ARCH_EARLY_PFN_TO_NID
1218 menu "Power management options"
1219 depends on !X86_VOYAGER
1221 config ARCH_HIBERNATION_HEADER
1223 depends on X86_64 && HIBERNATION
1226 source "kernel/power/Kconfig"
1228 source "drivers/acpi/Kconfig"
1231 tristate "APM (Advanced Power Management) BIOS support"
1232 depends on X86_32 && PM_SLEEP && !X86_VISWS
1234 APM is a BIOS specification for saving power using several different
1235 techniques. This is mostly useful for battery powered laptops with
1236 APM compliant BIOSes. If you say Y here, the system time will be
1237 reset after a RESUME operation, the /proc/apm device will provide
1238 battery status information, and user-space programs will receive
1239 notification of APM "events" (e.g. battery status change).
1241 If you select "Y" here, you can disable actual use of the APM
1242 BIOS by passing the "apm=off" option to the kernel at boot time.
1244 Note that the APM support is almost completely disabled for
1245 machines with more than one CPU.
1247 In order to use APM, you will need supporting software. For location
1248 and more information, read <file:Documentation/pm.txt> and the
1249 Battery Powered Linux mini-HOWTO, available from
1250 <http://www.tldp.org/docs.html#howto>.
1252 This driver does not spin down disk drives (see the hdparm(8)
1253 manpage ("man 8 hdparm") for that), and it doesn't turn off
1254 VESA-compliant "green" monitors.
1256 This driver does not support the TI 4000M TravelMate and the ACER
1257 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1258 desktop machines also don't have compliant BIOSes, and this driver
1259 may cause those machines to panic during the boot phase.
1261 Generally, if you don't have a battery in your machine, there isn't
1262 much point in using this driver and you should say N. If you get
1263 random kernel OOPSes or reboots that don't seem to be related to
1264 anything, try disabling/enabling this option (or disabling/enabling
1267 Some other things you should try when experiencing seemingly random,
1270 1) make sure that you have enough swap space and that it is
1272 2) pass the "no-hlt" option to the kernel
1273 3) switch on floating point emulation in the kernel and pass
1274 the "no387" option to the kernel
1275 4) pass the "floppy=nodma" option to the kernel
1276 5) pass the "mem=4M" option to the kernel (thereby disabling
1277 all but the first 4 MB of RAM)
1278 6) make sure that the CPU is not over clocked.
1279 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1280 8) disable the cache from your BIOS settings
1281 9) install a fan for the video card or exchange video RAM
1282 10) install a better fan for the CPU
1283 11) exchange RAM chips
1284 12) exchange the motherboard.
1286 To compile this driver as a module, choose M here: the
1287 module will be called apm.
1291 config APM_IGNORE_USER_SUSPEND
1292 bool "Ignore USER SUSPEND"
1294 This option will ignore USER SUSPEND requests. On machines with a
1295 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1296 series notebooks, it is necessary to say Y because of a BIOS bug.
1298 config APM_DO_ENABLE
1299 bool "Enable PM at boot time"
1301 Enable APM features at boot time. From page 36 of the APM BIOS
1302 specification: "When disabled, the APM BIOS does not automatically
1303 power manage devices, enter the Standby State, enter the Suspend
1304 State, or take power saving steps in response to CPU Idle calls."
1305 This driver will make CPU Idle calls when Linux is idle (unless this
1306 feature is turned off -- see "Do CPU IDLE calls", below). This
1307 should always save battery power, but more complicated APM features
1308 will be dependent on your BIOS implementation. You may need to turn
1309 this option off if your computer hangs at boot time when using APM
1310 support, or if it beeps continuously instead of suspending. Turn
1311 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1312 T400CDT. This is off by default since most machines do fine without
1316 bool "Make CPU Idle calls when idle"
1318 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1319 On some machines, this can activate improved power savings, such as
1320 a slowed CPU clock rate, when the machine is idle. These idle calls
1321 are made after the idle loop has run for some length of time (e.g.,
1322 333 mS). On some machines, this will cause a hang at boot time or
1323 whenever the CPU becomes idle. (On machines with more than one CPU,
1324 this option does nothing.)
1326 config APM_DISPLAY_BLANK
1327 bool "Enable console blanking using APM"
1329 Enable console blanking using the APM. Some laptops can use this to
1330 turn off the LCD backlight when the screen blanker of the Linux
1331 virtual console blanks the screen. Note that this is only used by
1332 the virtual console screen blanker, and won't turn off the backlight
1333 when using the X Window system. This also doesn't have anything to
1334 do with your VESA-compliant power-saving monitor. Further, this
1335 option doesn't work for all laptops -- it might not turn off your
1336 backlight at all, or it might print a lot of errors to the console,
1337 especially if you are using gpm.
1339 config APM_ALLOW_INTS
1340 bool "Allow interrupts during APM BIOS calls"
1342 Normally we disable external interrupts while we are making calls to
1343 the APM BIOS as a measure to lessen the effects of a badly behaving
1344 BIOS implementation. The BIOS should reenable interrupts if it
1345 needs to. Unfortunately, some BIOSes do not -- especially those in
1346 many of the newer IBM Thinkpads. If you experience hangs when you
1347 suspend, try setting this to Y. Otherwise, say N.
1349 config APM_REAL_MODE_POWER_OFF
1350 bool "Use real mode APM BIOS call to power off"
1352 Use real mode APM BIOS calls to switch off the computer. This is
1353 a work-around for a number of buggy BIOSes. Switch this option on if
1354 your computer crashes instead of powering off properly.
1358 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1360 source "drivers/cpuidle/Kconfig"
1365 menu "Bus options (PCI etc.)"
1368 bool "PCI support" if !X86_VISWS
1369 depends on !X86_VOYAGER
1370 default y if X86_VISWS
1371 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1373 Find out whether you have a PCI motherboard. PCI is the name of a
1374 bus system, i.e. the way the CPU talks to the other stuff inside
1375 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1376 VESA. If you have PCI, say Y, otherwise N.
1378 The PCI-HOWTO, available from
1379 <http://www.tldp.org/docs.html#howto>, contains valuable
1380 information about which PCI hardware does work under Linux and which
1384 prompt "PCI access mode"
1385 depends on X86_32 && PCI && !X86_VISWS
1388 On PCI systems, the BIOS can be used to detect the PCI devices and
1389 determine their configuration. However, some old PCI motherboards
1390 have BIOS bugs and may crash if this is done. Also, some embedded
1391 PCI-based systems don't have any BIOS at all. Linux can also try to
1392 detect the PCI hardware directly without using the BIOS.
1394 With this option, you can specify how Linux should detect the
1395 PCI devices. If you choose "BIOS", the BIOS will be used,
1396 if you choose "Direct", the BIOS won't be used, and if you
1397 choose "MMConfig", then PCI Express MMCONFIG will be used.
1398 If you choose "Any", the kernel will try MMCONFIG, then the
1399 direct access method and falls back to the BIOS if that doesn't
1400 work. If unsure, go with the default, which is "Any".
1405 config PCI_GOMMCONFIG
1418 depends on X86_32 && !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1421 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1424 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1429 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1438 bool "Support mmconfig PCI config space access"
1439 depends on X86_64 && PCI && ACPI
1442 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1443 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1445 DMA remapping (DMAR) devices support enables independent address
1446 translations for Direct Memory Access (DMA) from devices.
1447 These DMA remapping devices are reported via ACPI tables
1448 and include PCI device scope covered by these DMA
1452 bool "Support for Graphics workaround"
1456 Current Graphics drivers tend to use physical address
1457 for DMA and avoid using DMA APIs. Setting this config
1458 option permits the IOMMU driver to set a unity map for
1459 all the OS-visible memory. Hence the driver can continue
1460 to use physical addresses for DMA.
1462 config DMAR_FLOPPY_WA
1467 Floppy disk drivers are know to bypass DMA API calls
1468 thereby failing to work when IOMMU is enabled. This
1469 workaround will setup a 1:1 mapping for the first
1470 16M to make floppy (an ISA device) work.
1472 source "drivers/pci/pcie/Kconfig"
1474 source "drivers/pci/Kconfig"
1476 # x86_64 have no ISA slots, but do have ISA-style DMA.
1485 depends on !(X86_VOYAGER || X86_VISWS)
1487 Find out whether you have ISA slots on your motherboard. ISA is the
1488 name of a bus system, i.e. the way the CPU talks to the other stuff
1489 inside your box. Other bus systems are PCI, EISA, MicroChannel
1490 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1491 newer boards don't support it. If you have ISA, say Y, otherwise N.
1497 The Extended Industry Standard Architecture (EISA) bus was
1498 developed as an open alternative to the IBM MicroChannel bus.
1500 The EISA bus provided some of the features of the IBM MicroChannel
1501 bus while maintaining backward compatibility with cards made for
1502 the older ISA bus. The EISA bus saw limited use between 1988 and
1503 1995 when it was made obsolete by the PCI bus.
1505 Say Y here if you are building a kernel for an EISA-based machine.
1509 source "drivers/eisa/Kconfig"
1512 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1513 default y if X86_VOYAGER
1515 MicroChannel Architecture is found in some IBM PS/2 machines and
1516 laptops. It is a bus system similar to PCI or ISA. See
1517 <file:Documentation/mca.txt> (and especially the web page given
1518 there) before attempting to build an MCA bus kernel.
1520 source "drivers/mca/Kconfig"
1523 tristate "NatSemi SCx200 support"
1524 depends on !X86_VOYAGER
1526 This provides basic support for National Semiconductor's
1527 (now AMD's) Geode processors. The driver probes for the
1528 PCI-IDs of several on-chip devices, so its a good dependency
1529 for other scx200_* drivers.
1531 If compiled as a module, the driver is named scx200.
1533 config SCx200HR_TIMER
1534 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1535 depends on SCx200 && GENERIC_TIME
1538 This driver provides a clocksource built upon the on-chip
1539 27MHz high-resolution timer. Its also a workaround for
1540 NSC Geode SC-1100's buggy TSC, which loses time when the
1541 processor goes idle (as is done by the scheduler). The
1542 other workaround is idle=poll boot option.
1544 config GEODE_MFGPT_TIMER
1545 bool "Geode Multi-Function General Purpose Timer (MFGPT) events"
1546 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1549 This driver provides a clock event source based on the MFGPT
1550 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1551 MFGPTs have a better resolution and max interval than the
1552 generic PIT, and are suitable for use as high-res timers.
1558 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1560 source "drivers/pcmcia/Kconfig"
1562 source "drivers/pci/hotplug/Kconfig"
1567 menu "Executable file formats / Emulations"
1569 source "fs/Kconfig.binfmt"
1571 config IA32_EMULATION
1572 bool "IA32 Emulation"
1575 Include code to run 32-bit programs under a 64-bit kernel. You should
1576 likely turn this on, unless you're 100% sure that you don't have any
1577 32-bit programs left.
1580 tristate "IA32 a.out support"
1581 depends on IA32_EMULATION
1583 Support old a.out binaries in the 32bit emulation.
1587 depends on IA32_EMULATION
1590 config COMPAT_FOR_U64_ALIGNMENT
1594 config SYSVIPC_COMPAT
1596 depends on X86_64 && COMPAT && SYSVIPC
1602 source "net/Kconfig"
1604 source "drivers/Kconfig"
1606 source "drivers/firmware/Kconfig"
1610 source "kernel/Kconfig.instrumentation"
1612 source "arch/x86/Kconfig.debug"
1614 source "security/Kconfig"
1616 source "crypto/Kconfig"
1618 source "lib/Kconfig"
projects / firefly-linux-kernel-4.4.55.git / blob