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
25 config GENERIC_CMOS_UPDATE
28 config CLOCKSOURCE_WATCHDOG
31 config GENERIC_CLOCKEVENTS
34 config GENERIC_CLOCKEVENTS_BROADCAST
36 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
38 config LOCKDEP_SUPPORT
41 config STACKTRACE_SUPPORT
44 config SEMAPHORE_SLEEPERS
59 config GENERIC_ISA_DMA
69 config GENERIC_HWEIGHT
72 config ARCH_MAY_HAVE_PC_FDC
78 config RWSEM_GENERIC_SPINLOCK
81 config RWSEM_XCHGADD_ALGORITHM
84 config ARCH_HAS_ILOG2_U32
87 config ARCH_HAS_ILOG2_U64
90 config GENERIC_CALIBRATE_DELAY
93 config GENERIC_TIME_VSYSCALL
97 config ARCH_SUPPORTS_OPROFILE
106 config ARCH_POPULATES_NODE_MAP
113 # Use the generic interrupt handling code in kernel/irq/:
114 config GENERIC_HARDIRQS
118 config GENERIC_IRQ_PROBE
122 config GENERIC_PENDING_IRQ
124 depends on GENERIC_HARDIRQS && SMP
129 depends on X86_32 && SMP && !X86_VOYAGER
135 depends on (X86_32 && !(X86_VISWS || X86_VOYAGER)) || (X86_64 && !MK8)
138 config X86_BIOS_REBOOT
140 depends on X86_32 && !(X86_VISWS || X86_VOYAGER)
143 config X86_TRAMPOLINE
145 depends on X86_SMP || (X86_VOYAGER && SMP)
150 source "init/Kconfig"
152 menu "Processor type and features"
154 source "kernel/time/Kconfig"
157 bool "Symmetric multi-processing support"
159 This enables support for systems with more than one CPU. If you have
160 a system with only one CPU, like most personal computers, say N. If
161 you have a system with more than one CPU, say Y.
163 If you say N here, the kernel will run on single and multiprocessor
164 machines, but will use only one CPU of a multiprocessor machine. If
165 you say Y here, the kernel will run on many, but not all,
166 singleprocessor machines. On a singleprocessor machine, the kernel
167 will run faster if you say N here.
169 Note that if you say Y here and choose architecture "586" or
170 "Pentium" under "Processor family", the kernel will not work on 486
171 architectures. Similarly, multiprocessor kernels for the "PPro"
172 architecture may not work on all Pentium based boards.
174 People using multiprocessor machines who say Y here should also say
175 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
176 Management" code will be disabled if you say Y here.
178 See also the <file:Documentation/smp.txt>,
179 <file:Documentation/i386/IO-APIC.txt>,
180 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
181 <http://www.tldp.org/docs.html#howto>.
183 If you don't know what to do here, say N.
186 prompt "Subarchitecture Type"
192 Choose this option if your computer is a standard PC or compatible.
198 Select this for an AMD Elan processor.
200 Do not use this option for K6/Athlon/Opteron processors!
202 If unsure, choose "PC-compatible" instead.
207 select SMP if !BROKEN
209 Voyager is an MCA-based 32-way capable SMP architecture proprietary
210 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
214 If you do not specifically know you have a Voyager based machine,
215 say N here, otherwise the kernel you build will not be bootable.
218 bool "NUMAQ (IBM/Sequent)"
223 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
224 multiquad box. This changes the way that processors are bootstrapped,
225 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
226 You will need a new lynxer.elf file to flash your firmware with - send
227 email to <Martin.Bligh@us.ibm.com>.
230 bool "Summit/EXA (IBM x440)"
231 depends on X86_32 && SMP
233 This option is needed for IBM systems that use the Summit/EXA chipset.
234 In particular, it is needed for the x440.
236 If you don't have one of these computers, you should say N here.
237 If you want to build a NUMA kernel, you must select ACPI.
240 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
241 depends on X86_32 && SMP
243 This option is needed for the systems that have more than 8 CPUs
244 and if the system is not of any sub-arch type above.
246 If you don't have such a system, you should say N here.
249 bool "SGI 320/540 (Visual Workstation)"
252 The SGI Visual Workstation series is an IA32-based workstation
253 based on SGI systems chips with some legacy PC hardware attached.
255 Say Y here to create a kernel to run on the SGI 320 or 540.
257 A kernel compiled for the Visual Workstation will not run on PCs
258 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
260 config X86_GENERICARCH
261 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
264 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
265 It is intended for a generic binary kernel.
266 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
269 bool "Support for Unisys ES7000 IA32 series"
270 depends on X86_32 && SMP
272 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
273 supposed to run on an IA32-based Unisys ES7000 system.
274 Only choose this option if you have such a system, otherwise you
278 bool "Support for ScaleMP vSMP"
279 depends on X86_64 && PCI
281 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
282 supposed to run on these EM64T-based machines. Only choose this option
283 if you have one of these machines.
287 config SCHED_NO_NO_OMIT_FRAME_POINTER
289 prompt "Single-depth WCHAN output"
292 Calculate simpler /proc/<PID>/wchan values. If this option
293 is disabled then wchan values will recurse back to the
294 caller function. This provides more accurate wchan values,
295 at the expense of slightly more scheduling overhead.
297 If in doubt, say "Y".
301 depends on X86_32 && !(X86_VISWS || X86_VOYAGER)
303 This changes the kernel so it can modify itself when it is run
304 under a hypervisor, potentially improving performance significantly
305 over full virtualization. However, when run without a hypervisor
306 the kernel is theoretically slower and slightly larger.
308 menuconfig PARAVIRT_GUEST
309 bool "Paravirtualized guest support"
312 Say Y here to get to see options related to running Linux under
313 various hypervisors. This option alone does not add any kernel code.
315 If you say N, all options in this submenu will be skipped and disabled.
319 source "arch/x86/xen/Kconfig"
322 bool "VMI Guest support"
324 depends on !(X86_VISWS || X86_VOYAGER)
326 VMI provides a paravirtualized interface to the VMware ESX server
327 (it could be used by other hypervisors in theory too, but is not
328 at the moment), by linking the kernel to a GPL-ed ROM module
329 provided by the hypervisor.
331 source "arch/x86/lguest/Kconfig"
337 depends on X86_32 && ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
340 config HAVE_ARCH_PARSE_SRAT
344 config X86_SUMMIT_NUMA
346 depends on X86_32 && NUMA && (X86_SUMMIT || X86_GENERICARCH)
348 config X86_CYCLONE_TIMER
350 depends on X86_32 && X86_SUMMIT || X86_GENERICARCH
352 config ES7000_CLUSTERED_APIC
354 depends on SMP && X86_ES7000 && MPENTIUMIII
356 source "arch/x86/Kconfig.cpu"
360 prompt "HPET Timer Support" if X86_32
362 Use the IA-PC HPET (High Precision Event Timer) to manage
363 time in preference to the PIT and RTC, if a HPET is
365 HPET is the next generation timer replacing legacy 8254s.
366 The HPET provides a stable time base on SMP
367 systems, unlike the TSC, but it is more expensive to access,
368 as it is off-chip. You can find the HPET spec at
369 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
371 You can safely choose Y here. However, HPET will only be
372 activated if the platform and the BIOS support this feature.
373 Otherwise the 8254 will be used for timing services.
375 Choose N to continue using the legacy 8254 timer.
377 config HPET_EMULATE_RTC
379 depends on HPET_TIMER && RTC=y
381 # Mark as embedded because too many people got it wrong.
382 # The code disables itself when not needed.
384 bool "GART IOMMU support" if EMBEDDED
388 depends on X86_64 && PCI
390 Support for full DMA access of devices with 32bit memory access only
391 on systems with more than 3GB. This is usually needed for USB,
392 sound, many IDE/SATA chipsets and some other devices.
393 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
394 based hardware IOMMU and a software bounce buffer based IOMMU used
395 on Intel systems and as fallback.
396 The code is only active when needed (enough memory and limited
397 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
401 bool "IBM Calgary IOMMU support"
403 depends on X86_64 && PCI && EXPERIMENTAL
405 Support for hardware IOMMUs in IBM's xSeries x366 and x460
406 systems. Needed to run systems with more than 3GB of memory
407 properly with 32-bit PCI devices that do not support DAC
408 (Double Address Cycle). Calgary also supports bus level
409 isolation, where all DMAs pass through the IOMMU. This
410 prevents them from going anywhere except their intended
411 destination. This catches hard-to-find kernel bugs and
412 mis-behaving drivers and devices that do not use the DMA-API
413 properly to set up their DMA buffers. The IOMMU can be
414 turned off at boot time with the iommu=off parameter.
415 Normally the kernel will make the right choice by itself.
418 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
420 prompt "Should Calgary be enabled by default?"
421 depends on CALGARY_IOMMU
423 Should Calgary be enabled by default? if you choose 'y', Calgary
424 will be used (if it exists). If you choose 'n', Calgary will not be
425 used even if it exists. If you choose 'n' and would like to use
426 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
429 # need this always selected by IOMMU for the VIA workaround
433 Support for software bounce buffers used on x86-64 systems
434 which don't have a hardware IOMMU (e.g. the current generation
435 of Intel's x86-64 CPUs). Using this PCI devices which can only
436 access 32-bits of memory can be used on systems with more than
437 3 GB of memory. If unsure, say Y.
441 int "Maximum number of CPUs (2-255)"
444 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
447 This allows you to specify the maximum number of CPUs which this
448 kernel will support. The maximum supported value is 255 and the
449 minimum value which makes sense is 2.
451 This is purely to save memory - each supported CPU adds
452 approximately eight kilobytes to the kernel image.
455 bool "SMT (Hyperthreading) scheduler support"
456 depends on (X86_64 && SMP) || (X86_32 && X86_HT)
458 SMT scheduler support improves the CPU scheduler's decision making
459 when dealing with Intel Pentium 4 chips with HyperThreading at a
460 cost of slightly increased overhead in some places. If unsure say
465 prompt "Multi-core scheduler support"
466 depends on (X86_64 && SMP) || (X86_32 && X86_HT)
468 Multi-core scheduler support improves the CPU scheduler's decision
469 making when dealing with multi-core CPU chips at a cost of slightly
470 increased overhead in some places. If unsure say N here.
472 source "kernel/Kconfig.preempt"
475 bool "Local APIC support on uniprocessors"
476 depends on X86_32 && !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
478 A local APIC (Advanced Programmable Interrupt Controller) is an
479 integrated interrupt controller in the CPU. If you have a single-CPU
480 system which has a processor with a local APIC, you can say Y here to
481 enable and use it. If you say Y here even though your machine doesn't
482 have a local APIC, then the kernel will still run with no slowdown at
483 all. The local APIC supports CPU-generated self-interrupts (timer,
484 performance counters), and the NMI watchdog which detects hard
488 bool "IO-APIC support on uniprocessors"
489 depends on X86_UP_APIC
491 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
492 SMP-capable replacement for PC-style interrupt controllers. Most
493 SMP systems and many recent uniprocessor systems have one.
495 If you have a single-CPU system with an IO-APIC, you can say Y here
496 to use it. If you say Y here even though your machine doesn't have
497 an IO-APIC, then the kernel will still run with no slowdown at all.
499 config X86_LOCAL_APIC
501 depends on X86_64 || (X86_32 && (X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH))
505 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH))
507 config X86_VISWS_APIC
509 depends on X86_32 && X86_VISWS
512 bool "Machine Check Exception"
513 depends on !X86_VOYAGER
515 Machine Check Exception support allows the processor to notify the
516 kernel if it detects a problem (e.g. overheating, component failure).
517 The action the kernel takes depends on the severity of the problem,
518 ranging from a warning message on the console, to halting the machine.
519 Your processor must be a Pentium or newer to support this - check the
520 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
521 have a design flaw which leads to false MCE events - hence MCE is
522 disabled on all P5 processors, unless explicitly enabled with "mce"
523 as a boot argument. Similarly, if MCE is built in and creates a
524 problem on some new non-standard machine, you can boot with "nomce"
525 to disable it. MCE support simply ignores non-MCE processors like
526 the 386 and 486, so nearly everyone can say Y here.
530 prompt "Intel MCE features"
531 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
533 Additional support for intel specific MCE features such as
538 prompt "AMD MCE features"
539 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
541 Additional support for AMD specific MCE features such as
542 the DRAM Error Threshold.
544 config X86_MCE_NONFATAL
545 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
546 depends on X86_32 && X86_MCE
548 Enabling this feature starts a timer that triggers every 5 seconds which
549 will look at the machine check registers to see if anything happened.
550 Non-fatal problems automatically get corrected (but still logged).
551 Disable this if you don't want to see these messages.
552 Seeing the messages this option prints out may be indicative of dying
553 or out-of-spec (ie, overclocked) hardware.
554 This option only does something on certain CPUs.
555 (AMD Athlon/Duron and Intel Pentium 4)
557 config X86_MCE_P4THERMAL
558 bool "check for P4 thermal throttling interrupt."
559 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
561 Enabling this feature will cause a message to be printed when the P4
562 enters thermal throttling.
565 bool "Enable VM86 support" if EMBEDDED
569 This option is required by programs like DOSEMU to run 16-bit legacy
570 code on X86 processors. It also may be needed by software like
571 XFree86 to initialize some video cards via BIOS. Disabling this
572 option saves about 6k.
575 tristate "Toshiba Laptop support"
578 This adds a driver to safely access the System Management Mode of
579 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
580 not work on models with a Phoenix BIOS. The System Management Mode
581 is used to set the BIOS and power saving options on Toshiba portables.
583 For information on utilities to make use of this driver see the
584 Toshiba Linux utilities web site at:
585 <http://www.buzzard.org.uk/toshiba/>.
587 Say Y if you intend to run this kernel on a Toshiba portable.
591 tristate "Dell laptop support"
594 This adds a driver to safely access the System Management Mode
595 of the CPU on the Dell Inspiron 8000. The System Management Mode
596 is used to read cpu temperature and cooling fan status and to
597 control the fans on the I8K portables.
599 This driver has been tested only on the Inspiron 8000 but it may
600 also work with other Dell laptops. You can force loading on other
601 models by passing the parameter `force=1' to the module. Use at
604 For information on utilities to make use of this driver see the
605 I8K Linux utilities web site at:
606 <http://people.debian.org/~dz/i8k/>
608 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
611 config X86_REBOOTFIXUPS
613 prompt "Enable X86 board specific fixups for reboot"
614 depends on X86_32 && X86
616 This enables chipset and/or board specific fixups to be done
617 in order to get reboot to work correctly. This is only needed on
618 some combinations of hardware and BIOS. The symptom, for which
619 this config is intended, is when reboot ends with a stalled/hung
622 Currently, the only fixup is for the Geode machines using
623 CS5530A and CS5536 chipsets.
625 Say Y if you want to enable the fixup. Currently, it's safe to
626 enable this option even if you don't need it.
630 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
633 If you say Y here, you will be able to update the microcode on
634 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
635 Pentium III, Pentium 4, Xeon etc. You will obviously need the
636 actual microcode binary data itself which is not shipped with the
639 For latest news and information on obtaining all the required
640 ingredients for this driver, check:
641 <http://www.urbanmyth.org/microcode/>.
643 To compile this driver as a module, choose M here: the
644 module will be called microcode.
646 config MICROCODE_OLD_INTERFACE
651 tristate "/dev/cpu/*/msr - Model-specific register support"
653 This device gives privileged processes access to the x86
654 Model-Specific Registers (MSRs). It is a character device with
655 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
656 MSR accesses are directed to a specific CPU on multi-processor
660 tristate "/dev/cpu/*/cpuid - CPU information support"
662 This device gives processes access to the x86 CPUID instruction to
663 be executed on a specific processor. It is a character device
664 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
668 prompt "High Memory Support"
669 default HIGHMEM4G if !X86_NUMAQ
670 default HIGHMEM64G if X86_NUMAQ
675 depends on !X86_NUMAQ
677 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
678 However, the address space of 32-bit x86 processors is only 4
679 Gigabytes large. That means that, if you have a large amount of
680 physical memory, not all of it can be "permanently mapped" by the
681 kernel. The physical memory that's not permanently mapped is called
684 If you are compiling a kernel which will never run on a machine with
685 more than 1 Gigabyte total physical RAM, answer "off" here (default
686 choice and suitable for most users). This will result in a "3GB/1GB"
687 split: 3GB are mapped so that each process sees a 3GB virtual memory
688 space and the remaining part of the 4GB virtual memory space is used
689 by the kernel to permanently map as much physical memory as
692 If the machine has between 1 and 4 Gigabytes physical RAM, then
695 If more than 4 Gigabytes is used then answer "64GB" here. This
696 selection turns Intel PAE (Physical Address Extension) mode on.
697 PAE implements 3-level paging on IA32 processors. PAE is fully
698 supported by Linux, PAE mode is implemented on all recent Intel
699 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
700 then the kernel will not boot on CPUs that don't support PAE!
702 The actual amount of total physical memory will either be
703 auto detected or can be forced by using a kernel command line option
704 such as "mem=256M". (Try "man bootparam" or see the documentation of
705 your boot loader (lilo or loadlin) about how to pass options to the
706 kernel at boot time.)
708 If unsure, say "off".
712 depends on !X86_NUMAQ
714 Select this if you have a 32-bit processor and between 1 and 4
715 gigabytes of physical RAM.
719 depends on !M386 && !M486
722 Select this if you have a 32-bit processor and more than 4
723 gigabytes of physical RAM.
728 depends on EXPERIMENTAL
729 prompt "Memory split" if EMBEDDED
733 Select the desired split between kernel and user memory.
735 If the address range available to the kernel is less than the
736 physical memory installed, the remaining memory will be available
737 as "high memory". Accessing high memory is a little more costly
738 than low memory, as it needs to be mapped into the kernel first.
739 Note that increasing the kernel address space limits the range
740 available to user programs, making the address space there
741 tighter. Selecting anything other than the default 3G/1G split
742 will also likely make your kernel incompatible with binary-only
745 If you are not absolutely sure what you are doing, leave this
749 bool "3G/1G user/kernel split"
750 config VMSPLIT_3G_OPT
752 bool "3G/1G user/kernel split (for full 1G low memory)"
754 bool "2G/2G user/kernel split"
755 config VMSPLIT_2G_OPT
757 bool "2G/2G user/kernel split (for full 2G low memory)"
759 bool "1G/3G user/kernel split"
764 default 0xB0000000 if VMSPLIT_3G_OPT
765 default 0x80000000 if VMSPLIT_2G
766 default 0x78000000 if VMSPLIT_2G_OPT
767 default 0x40000000 if VMSPLIT_1G
773 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
777 prompt "PAE (Physical Address Extension) Support"
778 depends on X86_32 && !HIGHMEM4G
779 select RESOURCES_64BIT
781 PAE is required for NX support, and furthermore enables
782 larger swapspace support for non-overcommit purposes. It
783 has the cost of more pagetable lookup overhead, and also
784 consumes more pagetable space per process.
786 # Common NUMA Features
788 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
790 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL)
792 default y if (X86_NUMAQ || X86_SUMMIT)
794 Enable NUMA (Non Uniform Memory Access) support.
795 The kernel will try to allocate memory used by a CPU on the
796 local memory controller of the CPU and add some more
797 NUMA awareness to the kernel.
799 For i386 this is currently highly experimental and should be only
800 used for kernel development. It might also cause boot failures.
801 For x86_64 this is recommended on all multiprocessor Opteron systems.
802 If the system is EM64T, you should say N unless your system is
805 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
806 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
810 prompt "Old style AMD Opteron NUMA detection"
811 depends on X86_64 && NUMA && PCI
813 Enable K8 NUMA node topology detection. You should say Y here if
814 you have a multi processor AMD K8 system. This uses an old
815 method to read the NUMA configuration directly from the builtin
816 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
817 instead, which also takes priority if both are compiled in.
819 config X86_64_ACPI_NUMA
821 prompt "ACPI NUMA detection"
822 depends on X86_64 && NUMA && ACPI && PCI
825 Enable ACPI SRAT based node topology detection.
828 bool "NUMA emulation"
829 depends on X86_64 && NUMA
831 Enable NUMA emulation. A flat machine will be split
832 into virtual nodes when booted with "numa=fake=N", where N is the
833 number of nodes. This is only useful for debugging.
837 default "6" if X86_64
838 default "4" if X86_NUMAQ
840 depends on NEED_MULTIPLE_NODES
842 config HAVE_ARCH_BOOTMEM_NODE
844 depends on X86_32 && NUMA
846 config ARCH_HAVE_MEMORY_PRESENT
848 depends on X86_32 && DISCONTIGMEM
850 config NEED_NODE_MEMMAP_SIZE
852 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
854 config HAVE_ARCH_ALLOC_REMAP
856 depends on X86_32 && NUMA
858 config ARCH_FLATMEM_ENABLE
860 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && X86_PC
862 config ARCH_DISCONTIGMEM_ENABLE
864 depends on NUMA && X86_32
866 config ARCH_DISCONTIGMEM_DEFAULT
868 depends on NUMA && X86_32
870 config ARCH_SPARSEMEM_DEFAULT
874 config ARCH_SPARSEMEM_ENABLE
876 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC)
877 select SPARSEMEM_STATIC if X86_32
878 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
880 config ARCH_SELECT_MEMORY_MODEL
882 depends on ARCH_SPARSEMEM_ENABLE
884 config ARCH_MEMORY_PROBE
886 depends on MEMORY_HOTPLUG
891 bool "Allocate 3rd-level pagetables from highmem"
892 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
894 The VM uses one page table entry for each page of physical memory.
895 For systems with a lot of RAM, this can be wasteful of precious
896 low memory. Setting this option will put user-space page table
897 entries in high memory.
899 config MATH_EMULATION
901 prompt "Math emulation" if X86_32
903 Linux can emulate a math coprocessor (used for floating point
904 operations) if you don't have one. 486DX and Pentium processors have
905 a math coprocessor built in, 486SX and 386 do not, unless you added
906 a 487DX or 387, respectively. (The messages during boot time can
907 give you some hints here ["man dmesg"].) Everyone needs either a
908 coprocessor or this emulation.
910 If you don't have a math coprocessor, you need to say Y here; if you
911 say Y here even though you have a coprocessor, the coprocessor will
912 be used nevertheless. (This behavior can be changed with the kernel
913 command line option "no387", which comes handy if your coprocessor
914 is broken. Try "man bootparam" or see the documentation of your boot
915 loader (lilo or loadlin) about how to pass options to the kernel at
916 boot time.) This means that it is a good idea to say Y here if you
917 intend to use this kernel on different machines.
919 More information about the internals of the Linux math coprocessor
920 emulation can be found in <file:arch/x86/math-emu/README>.
922 If you are not sure, say Y; apart from resulting in a 66 KB bigger
923 kernel, it won't hurt.
926 bool "MTRR (Memory Type Range Register) support"
928 On Intel P6 family processors (Pentium Pro, Pentium II and later)
929 the Memory Type Range Registers (MTRRs) may be used to control
930 processor access to memory ranges. This is most useful if you have
931 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
932 allows bus write transfers to be combined into a larger transfer
933 before bursting over the PCI/AGP bus. This can increase performance
934 of image write operations 2.5 times or more. Saying Y here creates a
935 /proc/mtrr file which may be used to manipulate your processor's
936 MTRRs. Typically the X server should use this.
938 This code has a reasonably generic interface so that similar
939 control registers on other processors can be easily supported
942 The Cyrix 6x86, 6x86MX and M II processors have Address Range
943 Registers (ARRs) which provide a similar functionality to MTRRs. For
944 these, the ARRs are used to emulate the MTRRs.
945 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
946 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
947 write-combining. All of these processors are supported by this code
948 and it makes sense to say Y here if you have one of them.
950 Saying Y here also fixes a problem with buggy SMP BIOSes which only
951 set the MTRRs for the boot CPU and not for the secondary CPUs. This
952 can lead to all sorts of problems, so it's good to say Y here.
954 You can safely say Y even if your machine doesn't have MTRRs, you'll
955 just add about 9 KB to your kernel.
957 See <file:Documentation/mtrr.txt> for more information.
961 prompt "Boot from EFI support"
964 This enables the kernel to boot on EFI platforms using
965 system configuration information passed to it from the firmware.
966 This also enables the kernel to use any EFI runtime services that are
967 available (such as the EFI variable services).
969 This option is only useful on systems that have EFI firmware
970 and will result in a kernel image that is ~8k larger. In addition,
971 you must use the latest ELILO loader available at
972 <http://elilo.sourceforge.net> in order to take advantage of
973 kernel initialization using EFI information (neither GRUB nor LILO know
974 anything about EFI). However, even with this option, the resultant
975 kernel should continue to boot on existing non-EFI platforms.
979 prompt "Enable kernel irq balancing"
980 depends on X86_32 && SMP && X86_IO_APIC
982 The default yes will allow the kernel to do irq load balancing.
983 Saying no will keep the kernel from doing irq load balancing.
985 # turning this on wastes a bunch of space.
986 # Summit needs it only when NUMA is on
989 depends on X86_32 && (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
993 prompt "Enable seccomp to safely compute untrusted bytecode"
996 This kernel feature is useful for number crunching applications
997 that may need to compute untrusted bytecode during their
998 execution. By using pipes or other transports made available to
999 the process as file descriptors supporting the read/write
1000 syscalls, it's possible to isolate those applications in
1001 their own address space using seccomp. Once seccomp is
1002 enabled via /proc/<pid>/seccomp, it cannot be disabled
1003 and the task is only allowed to execute a few safe syscalls
1004 defined by each seccomp mode.
1006 If unsure, say Y. Only embedded should say N here.
1008 config CC_STACKPROTECTOR
1009 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1010 depends on X86_64 && EXPERIMENTAL
1012 This option turns on the -fstack-protector GCC feature. This
1013 feature puts, at the beginning of critical functions, a canary
1014 value on the stack just before the return address, and validates
1015 the value just before actually returning. Stack based buffer
1016 overflows (that need to overwrite this return address) now also
1017 overwrite the canary, which gets detected and the attack is then
1018 neutralized via a kernel panic.
1020 This feature requires gcc version 4.2 or above, or a distribution
1021 gcc with the feature backported. Older versions are automatically
1022 detected and for those versions, this configuration option is ignored.
1024 config CC_STACKPROTECTOR_ALL
1025 bool "Use stack-protector for all functions"
1026 depends on CC_STACKPROTECTOR
1028 Normally, GCC only inserts the canary value protection for
1029 functions that use large-ish on-stack buffers. By enabling
1030 this option, GCC will be asked to do this for ALL functions.
1032 source kernel/Kconfig.hz
1035 bool "kexec system call"
1037 kexec is a system call that implements the ability to shutdown your
1038 current kernel, and to start another kernel. It is like a reboot
1039 but it is independent of the system firmware. And like a reboot
1040 you can start any kernel with it, not just Linux.
1042 The name comes from the similarity to the exec system call.
1044 It is an ongoing process to be certain the hardware in a machine
1045 is properly shutdown, so do not be surprised if this code does not
1046 initially work for you. It may help to enable device hotplugging
1047 support. As of this writing the exact hardware interface is
1048 strongly in flux, so no good recommendation can be made.
1051 bool "kernel crash dumps (EXPERIMENTAL)"
1052 depends on EXPERIMENTAL
1053 depends on X86_64 || (X86_32 && HIGHMEM)
1055 Generate crash dump after being started by kexec.
1056 This should be normally only set in special crash dump kernels
1057 which are loaded in the main kernel with kexec-tools into
1058 a specially reserved region and then later executed after
1059 a crash by kdump/kexec. The crash dump kernel must be compiled
1060 to a memory address not used by the main kernel or BIOS using
1061 PHYSICAL_START, or it must be built as a relocatable image
1062 (CONFIG_RELOCATABLE=y).
1063 For more details see Documentation/kdump/kdump.txt
1065 config PHYSICAL_START
1066 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1067 default "0x1000000" if X86_NUMAQ
1068 default "0x200000" if X86_64
1071 This gives the physical address where the kernel is loaded.
1073 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1074 bzImage will decompress itself to above physical address and
1075 run from there. Otherwise, bzImage will run from the address where
1076 it has been loaded by the boot loader and will ignore above physical
1079 In normal kdump cases one does not have to set/change this option
1080 as now bzImage can be compiled as a completely relocatable image
1081 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1082 address. This option is mainly useful for the folks who don't want
1083 to use a bzImage for capturing the crash dump and want to use a
1084 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1085 to be specifically compiled to run from a specific memory area
1086 (normally a reserved region) and this option comes handy.
1088 So if you are using bzImage for capturing the crash dump, leave
1089 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1090 Otherwise if you plan to use vmlinux for capturing the crash dump
1091 change this value to start of the reserved region (Typically 16MB
1092 0x1000000). In other words, it can be set based on the "X" value as
1093 specified in the "crashkernel=YM@XM" command line boot parameter
1094 passed to the panic-ed kernel. Typically this parameter is set as
1095 crashkernel=64M@16M. Please take a look at
1096 Documentation/kdump/kdump.txt for more details about crash dumps.
1098 Usage of bzImage for capturing the crash dump is recommended as
1099 one does not have to build two kernels. Same kernel can be used
1100 as production kernel and capture kernel. Above option should have
1101 gone away after relocatable bzImage support is introduced. But it
1102 is present because there are users out there who continue to use
1103 vmlinux for dump capture. This option should go away down the
1106 Don't change this unless you know what you are doing.
1109 bool "Build a relocatable kernel (EXPERIMENTAL)"
1110 depends on EXPERIMENTAL
1112 This builds a kernel image that retains relocation information
1113 so it can be loaded someplace besides the default 1MB.
1114 The relocations tend to make the kernel binary about 10% larger,
1115 but are discarded at runtime.
1117 One use is for the kexec on panic case where the recovery kernel
1118 must live at a different physical address than the primary
1121 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1122 it has been loaded at and the compile time physical address
1123 (CONFIG_PHYSICAL_START) is ignored.
1125 config PHYSICAL_ALIGN
1127 prompt "Alignment value to which kernel should be aligned" if X86_32
1128 default "0x100000" if X86_32
1129 default "0x200000" if X86_64
1130 range 0x2000 0x400000
1132 This value puts the alignment restrictions on physical address
1133 where kernel is loaded and run from. Kernel is compiled for an
1134 address which meets above alignment restriction.
1136 If bootloader loads the kernel at a non-aligned address and
1137 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1138 address aligned to above value and run from there.
1140 If bootloader loads the kernel at a non-aligned address and
1141 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1142 load address and decompress itself to the address it has been
1143 compiled for and run from there. The address for which kernel is
1144 compiled already meets above alignment restrictions. Hence the
1145 end result is that kernel runs from a physical address meeting
1146 above alignment restrictions.
1148 Don't change this unless you know what you are doing.
1151 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
1152 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
1154 Say Y here to experiment with turning CPUs off and on, and to
1155 enable suspend on SMP systems. CPUs can be controlled through
1156 /sys/devices/system/cpu.
1157 Say N if you want to disable CPU hotplug and don't need to
1162 prompt "Compat VDSO support"
1163 depends on X86_32 || IA32_EMULATION
1165 Map the 32-bit VDSO to the predictable old-style address too.
1167 Say N here if you are running a sufficiently recent glibc
1168 version (2.3.3 or later), to remove the high-mapped
1169 VDSO mapping and to exclusively use the randomized VDSO.
1175 config ARCH_ENABLE_MEMORY_HOTPLUG
1177 depends on X86_64 || (X86_32 && HIGHMEM)
1179 config HAVE_ARCH_EARLY_PFN_TO_NID
1183 menu "Power management options"
1184 depends on !X86_VOYAGER
1186 config ARCH_HIBERNATION_HEADER
1188 depends on X86_64 && HIBERNATION
1190 source "kernel/power/Kconfig"
1192 source "drivers/acpi/Kconfig"
1195 tristate "APM (Advanced Power Management) BIOS support"
1196 depends on X86_32 && PM_SLEEP && !X86_VISWS
1198 APM is a BIOS specification for saving power using several different
1199 techniques. This is mostly useful for battery powered laptops with
1200 APM compliant BIOSes. If you say Y here, the system time will be
1201 reset after a RESUME operation, the /proc/apm device will provide
1202 battery status information, and user-space programs will receive
1203 notification of APM "events" (e.g. battery status change).
1205 If you select "Y" here, you can disable actual use of the APM
1206 BIOS by passing the "apm=off" option to the kernel at boot time.
1208 Note that the APM support is almost completely disabled for
1209 machines with more than one CPU.
1211 In order to use APM, you will need supporting software. For location
1212 and more information, read <file:Documentation/pm.txt> and the
1213 Battery Powered Linux mini-HOWTO, available from
1214 <http://www.tldp.org/docs.html#howto>.
1216 This driver does not spin down disk drives (see the hdparm(8)
1217 manpage ("man 8 hdparm") for that), and it doesn't turn off
1218 VESA-compliant "green" monitors.
1220 This driver does not support the TI 4000M TravelMate and the ACER
1221 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1222 desktop machines also don't have compliant BIOSes, and this driver
1223 may cause those machines to panic during the boot phase.
1225 Generally, if you don't have a battery in your machine, there isn't
1226 much point in using this driver and you should say N. If you get
1227 random kernel OOPSes or reboots that don't seem to be related to
1228 anything, try disabling/enabling this option (or disabling/enabling
1231 Some other things you should try when experiencing seemingly random,
1234 1) make sure that you have enough swap space and that it is
1236 2) pass the "no-hlt" option to the kernel
1237 3) switch on floating point emulation in the kernel and pass
1238 the "no387" option to the kernel
1239 4) pass the "floppy=nodma" option to the kernel
1240 5) pass the "mem=4M" option to the kernel (thereby disabling
1241 all but the first 4 MB of RAM)
1242 6) make sure that the CPU is not over clocked.
1243 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1244 8) disable the cache from your BIOS settings
1245 9) install a fan for the video card or exchange video RAM
1246 10) install a better fan for the CPU
1247 11) exchange RAM chips
1248 12) exchange the motherboard.
1250 To compile this driver as a module, choose M here: the
1251 module will be called apm.
1255 config APM_IGNORE_USER_SUSPEND
1256 bool "Ignore USER SUSPEND"
1258 This option will ignore USER SUSPEND requests. On machines with a
1259 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1260 series notebooks, it is necessary to say Y because of a BIOS bug.
1262 config APM_DO_ENABLE
1263 bool "Enable PM at boot time"
1265 Enable APM features at boot time. From page 36 of the APM BIOS
1266 specification: "When disabled, the APM BIOS does not automatically
1267 power manage devices, enter the Standby State, enter the Suspend
1268 State, or take power saving steps in response to CPU Idle calls."
1269 This driver will make CPU Idle calls when Linux is idle (unless this
1270 feature is turned off -- see "Do CPU IDLE calls", below). This
1271 should always save battery power, but more complicated APM features
1272 will be dependent on your BIOS implementation. You may need to turn
1273 this option off if your computer hangs at boot time when using APM
1274 support, or if it beeps continuously instead of suspending. Turn
1275 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1276 T400CDT. This is off by default since most machines do fine without
1280 bool "Make CPU Idle calls when idle"
1282 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1283 On some machines, this can activate improved power savings, such as
1284 a slowed CPU clock rate, when the machine is idle. These idle calls
1285 are made after the idle loop has run for some length of time (e.g.,
1286 333 mS). On some machines, this will cause a hang at boot time or
1287 whenever the CPU becomes idle. (On machines with more than one CPU,
1288 this option does nothing.)
1290 config APM_DISPLAY_BLANK
1291 bool "Enable console blanking using APM"
1293 Enable console blanking using the APM. Some laptops can use this to
1294 turn off the LCD backlight when the screen blanker of the Linux
1295 virtual console blanks the screen. Note that this is only used by
1296 the virtual console screen blanker, and won't turn off the backlight
1297 when using the X Window system. This also doesn't have anything to
1298 do with your VESA-compliant power-saving monitor. Further, this
1299 option doesn't work for all laptops -- it might not turn off your
1300 backlight at all, or it might print a lot of errors to the console,
1301 especially if you are using gpm.
1303 config APM_ALLOW_INTS
1304 bool "Allow interrupts during APM BIOS calls"
1306 Normally we disable external interrupts while we are making calls to
1307 the APM BIOS as a measure to lessen the effects of a badly behaving
1308 BIOS implementation. The BIOS should reenable interrupts if it
1309 needs to. Unfortunately, some BIOSes do not -- especially those in
1310 many of the newer IBM Thinkpads. If you experience hangs when you
1311 suspend, try setting this to Y. Otherwise, say N.
1313 config APM_REAL_MODE_POWER_OFF
1314 bool "Use real mode APM BIOS call to power off"
1316 Use real mode APM BIOS calls to switch off the computer. This is
1317 a work-around for a number of buggy BIOSes. Switch this option on if
1318 your computer crashes instead of powering off properly.
1322 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1324 source "drivers/cpuidle/Kconfig"
1329 menu "Bus options (PCI etc.)"
1332 bool "PCI support" if !X86_VISWS
1333 depends on !X86_VOYAGER
1334 default y if X86_VISWS
1335 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1337 Find out whether you have a PCI motherboard. PCI is the name of a
1338 bus system, i.e. the way the CPU talks to the other stuff inside
1339 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1340 VESA. If you have PCI, say Y, otherwise N.
1342 The PCI-HOWTO, available from
1343 <http://www.tldp.org/docs.html#howto>, contains valuable
1344 information about which PCI hardware does work under Linux and which
1348 prompt "PCI access mode"
1349 depends on X86_32 && PCI && !X86_VISWS
1352 On PCI systems, the BIOS can be used to detect the PCI devices and
1353 determine their configuration. However, some old PCI motherboards
1354 have BIOS bugs and may crash if this is done. Also, some embedded
1355 PCI-based systems don't have any BIOS at all. Linux can also try to
1356 detect the PCI hardware directly without using the BIOS.
1358 With this option, you can specify how Linux should detect the
1359 PCI devices. If you choose "BIOS", the BIOS will be used,
1360 if you choose "Direct", the BIOS won't be used, and if you
1361 choose "MMConfig", then PCI Express MMCONFIG will be used.
1362 If you choose "Any", the kernel will try MMCONFIG, then the
1363 direct access method and falls back to the BIOS if that doesn't
1364 work. If unsure, go with the default, which is "Any".
1369 config PCI_GOMMCONFIG
1382 depends on X86_32 && !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1384 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1387 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1391 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1398 bool "Support mmconfig PCI config space access"
1399 depends on X86_64 && PCI && ACPI
1402 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1403 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1405 DMA remapping (DMAR) devices support enables independent address
1406 translations for Direct Memory Access (DMA) from devices.
1407 These DMA remapping devices are reported via ACPI tables
1408 and include PCI device scope covered by these DMA
1413 prompt "Support for Graphics workaround"
1416 Current Graphics drivers tend to use physical address
1417 for DMA and avoid using DMA APIs. Setting this config
1418 option permits the IOMMU driver to set a unity map for
1419 all the OS-visible memory. Hence the driver can continue
1420 to use physical addresses for DMA.
1422 config DMAR_FLOPPY_WA
1426 Floppy disk drivers are know to bypass DMA API calls
1427 thereby failing to work when IOMMU is enabled. This
1428 workaround will setup a 1:1 mapping for the first
1429 16M to make floppy (an ISA device) work.
1431 source "drivers/pci/pcie/Kconfig"
1433 source "drivers/pci/Kconfig"
1435 # x86_64 have no ISA slots, but do have ISA-style DMA.
1443 depends on !(X86_VOYAGER || X86_VISWS)
1445 Find out whether you have ISA slots on your motherboard. ISA is the
1446 name of a bus system, i.e. the way the CPU talks to the other stuff
1447 inside your box. Other bus systems are PCI, EISA, MicroChannel
1448 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1449 newer boards don't support it. If you have ISA, say Y, otherwise N.
1455 The Extended Industry Standard Architecture (EISA) bus was
1456 developed as an open alternative to the IBM MicroChannel bus.
1458 The EISA bus provided some of the features of the IBM MicroChannel
1459 bus while maintaining backward compatibility with cards made for
1460 the older ISA bus. The EISA bus saw limited use between 1988 and
1461 1995 when it was made obsolete by the PCI bus.
1463 Say Y here if you are building a kernel for an EISA-based machine.
1467 source "drivers/eisa/Kconfig"
1470 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1471 default y if X86_VOYAGER
1473 MicroChannel Architecture is found in some IBM PS/2 machines and
1474 laptops. It is a bus system similar to PCI or ISA. See
1475 <file:Documentation/mca.txt> (and especially the web page given
1476 there) before attempting to build an MCA bus kernel.
1478 source "drivers/mca/Kconfig"
1481 tristate "NatSemi SCx200 support"
1482 depends on !X86_VOYAGER
1484 This provides basic support for National Semiconductor's
1485 (now AMD's) Geode processors. The driver probes for the
1486 PCI-IDs of several on-chip devices, so its a good dependency
1487 for other scx200_* drivers.
1489 If compiled as a module, the driver is named scx200.
1491 config SCx200HR_TIMER
1492 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1493 depends on SCx200 && GENERIC_TIME
1496 This driver provides a clocksource built upon the on-chip
1497 27MHz high-resolution timer. Its also a workaround for
1498 NSC Geode SC-1100's buggy TSC, which loses time when the
1499 processor goes idle (as is done by the scheduler). The
1500 other workaround is idle=poll boot option.
1502 config GEODE_MFGPT_TIMER
1504 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1505 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1507 This driver provides a clock event source based on the MFGPT
1508 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1509 MFGPTs have a better resolution and max interval than the
1510 generic PIT, and are suitable for use as high-res timers.
1516 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1518 source "drivers/pcmcia/Kconfig"
1520 source "drivers/pci/hotplug/Kconfig"
1525 menu "Executable file formats / Emulations"
1527 source "fs/Kconfig.binfmt"
1529 config IA32_EMULATION
1530 bool "IA32 Emulation"
1533 Include code to run 32-bit programs under a 64-bit kernel. You should
1534 likely turn this on, unless you're 100% sure that you don't have any
1535 32-bit programs left.
1538 tristate "IA32 a.out support"
1539 depends on IA32_EMULATION
1541 Support old a.out binaries in the 32bit emulation.
1545 depends on IA32_EMULATION
1547 config COMPAT_FOR_U64_ALIGNMENT
1551 config SYSVIPC_COMPAT
1553 depends on X86_64 && COMPAT && SYSVIPC
1558 source "net/Kconfig"
1560 source "drivers/Kconfig"
1562 source "drivers/firmware/Kconfig"
1566 source "kernel/Kconfig.instrumentation"
1568 source "arch/x86/Kconfig.debug"
1570 source "security/Kconfig"
1572 source "crypto/Kconfig"
1574 source "lib/Kconfig"
projects / firefly-linux-kernel-4.4.55.git / blob