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
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_PERF_EVENTS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
33 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_DYNAMIC_FTRACE
36 select HAVE_FUNCTION_TRACER
37 select HAVE_FUNCTION_GRAPH_TRACER
38 select HAVE_FUNCTION_GRAPH_FP_TEST
39 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
40 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
41 select HAVE_SYSCALL_TRACEPOINTS
44 select HAVE_ARCH_TRACEHOOK
45 select HAVE_GENERIC_DMA_COHERENT if X86_32
46 select HAVE_EFFICIENT_UNALIGNED_ACCESS
47 select USER_STACKTRACE_SUPPORT
48 select HAVE_REGS_AND_STACK_ACCESS_API
49 select HAVE_DMA_API_DEBUG
50 select HAVE_KERNEL_GZIP
51 select HAVE_KERNEL_BZIP2
52 select HAVE_KERNEL_LZMA
53 select HAVE_KERNEL_LZO
54 select HAVE_HW_BREAKPOINT
57 select HAVE_ARCH_KMEMCHECK
58 select HAVE_USER_RETURN_NOTIFIER
62 default "elf32-i386" if X86_32
63 default "elf64-x86-64" if X86_64
67 default "arch/x86/configs/i386_defconfig" if X86_32
68 default "arch/x86/configs/x86_64_defconfig" if X86_64
73 config GENERIC_CMOS_UPDATE
76 config CLOCKSOURCE_WATCHDOG
79 config GENERIC_CLOCKEVENTS
82 config GENERIC_CLOCKEVENTS_BROADCAST
84 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
86 config LOCKDEP_SUPPORT
89 config STACKTRACE_SUPPORT
92 config HAVE_LATENCYTOP_SUPPORT
104 config GENERIC_ISA_DMA
113 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
115 config GENERIC_BUG_RELATIVE_POINTERS
118 config GENERIC_HWEIGHT
124 config ARCH_MAY_HAVE_PC_FDC
127 config RWSEM_GENERIC_SPINLOCK
130 config RWSEM_XCHGADD_ALGORITHM
133 config ARCH_HAS_CPU_IDLE_WAIT
136 config GENERIC_CALIBRATE_DELAY
139 config GENERIC_TIME_VSYSCALL
143 config ARCH_HAS_CPU_RELAX
146 config ARCH_HAS_DEFAULT_IDLE
149 config ARCH_HAS_CACHE_LINE_SIZE
152 config HAVE_SETUP_PER_CPU_AREA
155 config NEED_PER_CPU_EMBED_FIRST_CHUNK
158 config NEED_PER_CPU_PAGE_FIRST_CHUNK
161 config HAVE_CPUMASK_OF_CPU_MAP
164 config ARCH_HIBERNATION_POSSIBLE
167 config ARCH_SUSPEND_POSSIBLE
174 config ARCH_POPULATES_NODE_MAP
181 config ARCH_SUPPORTS_OPTIMIZED_INLINING
184 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
187 config HAVE_INTEL_TXT
189 depends on EXPERIMENTAL && DMAR && ACPI
191 # Use the generic interrupt handling code in kernel/irq/:
192 config GENERIC_HARDIRQS
196 config GENERIC_HARDIRQS_NO__DO_IRQ
199 config GENERIC_IRQ_PROBE
203 config GENERIC_PENDING_IRQ
205 depends on GENERIC_HARDIRQS && SMP
208 config USE_GENERIC_SMP_HELPERS
214 depends on X86_32 && SMP
218 depends on X86_64 && SMP
225 config X86_TRAMPOLINE
227 depends on SMP || (64BIT && ACPI_SLEEP)
230 config X86_32_LAZY_GS
232 depends on X86_32 && !CC_STACKPROTECTOR
236 source "init/Kconfig"
237 source "kernel/Kconfig.freezer"
239 menu "Processor type and features"
241 source "kernel/time/Kconfig"
244 bool "Symmetric multi-processing support"
246 This enables support for systems with more than one CPU. If you have
247 a system with only one CPU, like most personal computers, say N. If
248 you have a system with more than one CPU, say Y.
250 If you say N here, the kernel will run on single and multiprocessor
251 machines, but will use only one CPU of a multiprocessor machine. If
252 you say Y here, the kernel will run on many, but not all,
253 singleprocessor machines. On a singleprocessor machine, the kernel
254 will run faster if you say N here.
256 Note that if you say Y here and choose architecture "586" or
257 "Pentium" under "Processor family", the kernel will not work on 486
258 architectures. Similarly, multiprocessor kernels for the "PPro"
259 architecture may not work on all Pentium based boards.
261 People using multiprocessor machines who say Y here should also say
262 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
263 Management" code will be disabled if you say Y here.
265 See also <file:Documentation/i386/IO-APIC.txt>,
266 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
267 <http://www.tldp.org/docs.html#howto>.
269 If you don't know what to do here, say N.
272 bool "Support x2apic"
273 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
275 This enables x2apic support on CPUs that have this feature.
277 This allows 32-bit apic IDs (so it can support very large systems),
278 and accesses the local apic via MSRs not via mmio.
280 If you don't know what to do here, say N.
283 bool "Support sparse irq numbering"
284 depends on PCI_MSI || HT_IRQ
286 This enables support for sparse irqs. This is useful for distro
287 kernels that want to define a high CONFIG_NR_CPUS value but still
288 want to have low kernel memory footprint on smaller machines.
290 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
291 out the irq_desc[] array in a more NUMA-friendly way. )
293 If you don't know what to do here, say N.
297 depends on SPARSE_IRQ && NUMA
300 bool "Enable MPS table" if ACPI
302 depends on X86_LOCAL_APIC
304 For old smp systems that do not have proper acpi support. Newer systems
305 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
308 bool "Support for big SMP systems with more than 8 CPUs"
309 depends on X86_32 && SMP
311 This option is needed for the systems that have more than 8 CPUs
314 config X86_EXTENDED_PLATFORM
315 bool "Support for extended (non-PC) x86 platforms"
318 If you disable this option then the kernel will only support
319 standard PC platforms. (which covers the vast majority of
322 If you enable this option then you'll be able to select support
323 for the following (non-PC) 32 bit x86 platforms:
327 SGI 320/540 (Visual Workstation)
328 Summit/EXA (IBM x440)
329 Unisys ES7000 IA32 series
330 Moorestown MID devices
332 If you have one of these systems, or if you want to build a
333 generic distribution kernel, say Y here - otherwise say N.
337 config X86_EXTENDED_PLATFORM
338 bool "Support for extended (non-PC) x86 platforms"
341 If you disable this option then the kernel will only support
342 standard PC platforms. (which covers the vast majority of
345 If you enable this option then you'll be able to select support
346 for the following (non-PC) 64 bit x86 platforms:
350 If you have one of these systems, or if you want to build a
351 generic distribution kernel, say Y here - otherwise say N.
353 # This is an alphabetically sorted list of 64 bit extended platforms
354 # Please maintain the alphabetic order if and when there are additions
359 depends on X86_64 && PCI
360 depends on X86_EXTENDED_PLATFORM
362 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
363 supposed to run on these EM64T-based machines. Only choose this option
364 if you have one of these machines.
367 bool "SGI Ultraviolet"
369 depends on X86_EXTENDED_PLATFORM
371 depends on X86_X2APIC
373 This option is needed in order to support SGI Ultraviolet systems.
374 If you don't have one of these, you should say N here.
376 # Following is an alphabetically sorted list of 32 bit extended platforms
377 # Please maintain the alphabetic order if and when there are additions
382 depends on X86_EXTENDED_PLATFORM
384 Select this for an AMD Elan processor.
386 Do not use this option for K6/Athlon/Opteron processors!
388 If unsure, choose "PC-compatible" instead.
391 bool "Moorestown MID platform"
393 depends on X86_EXTENDED_PLATFORM
395 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
396 Internet Device(MID) platform. Moorestown consists of two chips:
397 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
398 Unlike standard x86 PCs, Moorestown does not have many legacy devices
399 nor standard legacy replacement devices/features. e.g. Moorestown does
400 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
403 bool "RDC R-321x SoC"
405 depends on X86_EXTENDED_PLATFORM
407 select X86_REBOOTFIXUPS
409 This option is needed for RDC R-321x system-on-chip, also known
411 If you don't have one of these chips, you should say N here.
413 config X86_32_NON_STANDARD
414 bool "Support non-standard 32-bit SMP architectures"
415 depends on X86_32 && SMP
416 depends on X86_EXTENDED_PLATFORM
418 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
419 subarchitectures. It is intended for a generic binary kernel.
420 if you select them all, kernel will probe it one by one. and will
423 # Alphabetically sorted list of Non standard 32 bit platforms
426 bool "NUMAQ (IBM/Sequent)"
427 depends on X86_32_NON_STANDARD
431 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
432 NUMA multiquad box. This changes the way that processors are
433 bootstrapped, and uses Clustered Logical APIC addressing mode instead
434 of Flat Logical. You will need a new lynxer.elf file to flash your
435 firmware with - send email to <Martin.Bligh@us.ibm.com>.
437 config X86_SUPPORTS_MEMORY_FAILURE
439 # MCE code calls memory_failure():
441 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
442 depends on !X86_NUMAQ
443 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
444 depends on X86_64 || !SPARSEMEM
445 select ARCH_SUPPORTS_MEMORY_FAILURE
449 bool "SGI 320/540 (Visual Workstation)"
450 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
451 depends on X86_32_NON_STANDARD
453 The SGI Visual Workstation series is an IA32-based workstation
454 based on SGI systems chips with some legacy PC hardware attached.
456 Say Y here to create a kernel to run on the SGI 320 or 540.
458 A kernel compiled for the Visual Workstation will run on general
459 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
462 bool "Summit/EXA (IBM x440)"
463 depends on X86_32_NON_STANDARD
465 This option is needed for IBM systems that use the Summit/EXA chipset.
466 In particular, it is needed for the x440.
469 bool "Unisys ES7000 IA32 series"
470 depends on X86_32_NON_STANDARD && X86_BIGSMP
472 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
473 supposed to run on an IA32-based Unisys ES7000 system.
475 config SCHED_OMIT_FRAME_POINTER
477 prompt "Single-depth WCHAN output"
480 Calculate simpler /proc/<PID>/wchan values. If this option
481 is disabled then wchan values will recurse back to the
482 caller function. This provides more accurate wchan values,
483 at the expense of slightly more scheduling overhead.
485 If in doubt, say "Y".
487 menuconfig PARAVIRT_GUEST
488 bool "Paravirtualized guest support"
490 Say Y here to get to see options related to running Linux under
491 various hypervisors. This option alone does not add any kernel code.
493 If you say N, all options in this submenu will be skipped and disabled.
497 source "arch/x86/xen/Kconfig"
500 bool "VMI Guest support (DEPRECATED)"
504 VMI provides a paravirtualized interface to the VMware ESX server
505 (it could be used by other hypervisors in theory too, but is not
506 at the moment), by linking the kernel to a GPL-ed ROM module
507 provided by the hypervisor.
509 As of September 2009, VMware has started a phased retirement
510 of this feature from VMware's products. Please see
511 feature-removal-schedule.txt for details. If you are
512 planning to enable this option, please note that you cannot
513 live migrate a VMI enabled VM to a future VMware product,
514 which doesn't support VMI. So if you expect your kernel to
515 seamlessly migrate to newer VMware products, keep this
519 bool "KVM paravirtualized clock"
521 select PARAVIRT_CLOCK
523 Turning on this option will allow you to run a paravirtualized clock
524 when running over the KVM hypervisor. Instead of relying on a PIT
525 (or probably other) emulation by the underlying device model, the host
526 provides the guest with timing infrastructure such as time of day, and
530 bool "KVM Guest support"
533 This option enables various optimizations for running under the KVM
536 source "arch/x86/lguest/Kconfig"
539 bool "Enable paravirtualization code"
541 This changes the kernel so it can modify itself when it is run
542 under a hypervisor, potentially improving performance significantly
543 over full virtualization. However, when run without a hypervisor
544 the kernel is theoretically slower and slightly larger.
546 config PARAVIRT_SPINLOCKS
547 bool "Paravirtualization layer for spinlocks"
548 depends on PARAVIRT && SMP && EXPERIMENTAL
550 Paravirtualized spinlocks allow a pvops backend to replace the
551 spinlock implementation with something virtualization-friendly
552 (for example, block the virtual CPU rather than spinning).
554 Unfortunately the downside is an up to 5% performance hit on
555 native kernels, with various workloads.
557 If you are unsure how to answer this question, answer N.
559 config PARAVIRT_CLOCK
565 config PARAVIRT_DEBUG
566 bool "paravirt-ops debugging"
567 depends on PARAVIRT && DEBUG_KERNEL
569 Enable to debug paravirt_ops internals. Specifically, BUG if
570 a paravirt_op is missing when it is called.
575 This option adds a kernel parameter 'memtest', which allows memtest
577 memtest=0, mean disabled; -- default
578 memtest=1, mean do 1 test pattern;
580 memtest=4, mean do 4 test patterns.
581 If you are unsure how to answer this question, answer N.
583 config X86_SUMMIT_NUMA
585 depends on X86_32 && NUMA && X86_32_NON_STANDARD
587 config X86_CYCLONE_TIMER
589 depends on X86_32_NON_STANDARD
591 source "arch/x86/Kconfig.cpu"
595 prompt "HPET Timer Support" if X86_32
597 Use the IA-PC HPET (High Precision Event Timer) to manage
598 time in preference to the PIT and RTC, if a HPET is
600 HPET is the next generation timer replacing legacy 8254s.
601 The HPET provides a stable time base on SMP
602 systems, unlike the TSC, but it is more expensive to access,
603 as it is off-chip. You can find the HPET spec at
604 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
606 You can safely choose Y here. However, HPET will only be
607 activated if the platform and the BIOS support this feature.
608 Otherwise the 8254 will be used for timing services.
610 Choose N to continue using the legacy 8254 timer.
612 config HPET_EMULATE_RTC
614 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
616 # Mark as embedded because too many people got it wrong.
617 # The code disables itself when not needed.
620 bool "Enable DMI scanning" if EMBEDDED
622 Enabled scanning of DMI to identify machine quirks. Say Y
623 here unless you have verified that your setup is not
624 affected by entries in the DMI blacklist. Required by PNP
628 bool "GART IOMMU support" if EMBEDDED
631 depends on X86_64 && PCI
633 Support for full DMA access of devices with 32bit memory access only
634 on systems with more than 3GB. This is usually needed for USB,
635 sound, many IDE/SATA chipsets and some other devices.
636 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
637 based hardware IOMMU and a software bounce buffer based IOMMU used
638 on Intel systems and as fallback.
639 The code is only active when needed (enough memory and limited
640 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
644 bool "IBM Calgary IOMMU support"
646 depends on X86_64 && PCI && EXPERIMENTAL
648 Support for hardware IOMMUs in IBM's xSeries x366 and x460
649 systems. Needed to run systems with more than 3GB of memory
650 properly with 32-bit PCI devices that do not support DAC
651 (Double Address Cycle). Calgary also supports bus level
652 isolation, where all DMAs pass through the IOMMU. This
653 prevents them from going anywhere except their intended
654 destination. This catches hard-to-find kernel bugs and
655 mis-behaving drivers and devices that do not use the DMA-API
656 properly to set up their DMA buffers. The IOMMU can be
657 turned off at boot time with the iommu=off parameter.
658 Normally the kernel will make the right choice by itself.
661 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
663 prompt "Should Calgary be enabled by default?"
664 depends on CALGARY_IOMMU
666 Should Calgary be enabled by default? if you choose 'y', Calgary
667 will be used (if it exists). If you choose 'n', Calgary will not be
668 used even if it exists. If you choose 'n' and would like to use
669 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
673 bool "AMD IOMMU support"
676 depends on X86_64 && PCI && ACPI
678 With this option you can enable support for AMD IOMMU hardware in
679 your system. An IOMMU is a hardware component which provides
680 remapping of DMA memory accesses from devices. With an AMD IOMMU you
681 can isolate the the DMA memory of different devices and protect the
682 system from misbehaving device drivers or hardware.
684 You can find out if your system has an AMD IOMMU if you look into
685 your BIOS for an option to enable it or if you have an IVRS ACPI
688 config AMD_IOMMU_STATS
689 bool "Export AMD IOMMU statistics to debugfs"
693 This option enables code in the AMD IOMMU driver to collect various
694 statistics about whats happening in the driver and exports that
695 information to userspace via debugfs.
698 # need this always selected by IOMMU for the VIA workaround
702 Support for software bounce buffers used on x86-64 systems
703 which don't have a hardware IOMMU (e.g. the current generation
704 of Intel's x86-64 CPUs). Using this PCI devices which can only
705 access 32-bits of memory can be used on systems with more than
706 3 GB of memory. If unsure, say Y.
709 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
712 def_bool (AMD_IOMMU || DMAR)
715 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
716 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
717 select CPUMASK_OFFSTACK
720 Configure maximum number of CPUS and NUMA Nodes for this architecture.
724 int "Maximum number of CPUs" if SMP && !MAXSMP
725 range 2 8 if SMP && X86_32 && !X86_BIGSMP
726 range 2 512 if SMP && !MAXSMP
728 default "4096" if MAXSMP
729 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
732 This allows you to specify the maximum number of CPUs which this
733 kernel will support. The maximum supported value is 512 and the
734 minimum value which makes sense is 2.
736 This is purely to save memory - each supported CPU adds
737 approximately eight kilobytes to the kernel image.
740 bool "SMT (Hyperthreading) scheduler support"
743 SMT scheduler support improves the CPU scheduler's decision making
744 when dealing with Intel Pentium 4 chips with HyperThreading at a
745 cost of slightly increased overhead in some places. If unsure say
750 prompt "Multi-core scheduler support"
753 Multi-core scheduler support improves the CPU scheduler's decision
754 making when dealing with multi-core CPU chips at a cost of slightly
755 increased overhead in some places. If unsure say N here.
757 source "kernel/Kconfig.preempt"
760 bool "Local APIC support on uniprocessors"
761 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
763 A local APIC (Advanced Programmable Interrupt Controller) is an
764 integrated interrupt controller in the CPU. If you have a single-CPU
765 system which has a processor with a local APIC, you can say Y here to
766 enable and use it. If you say Y here even though your machine doesn't
767 have a local APIC, then the kernel will still run with no slowdown at
768 all. The local APIC supports CPU-generated self-interrupts (timer,
769 performance counters), and the NMI watchdog which detects hard
773 bool "IO-APIC support on uniprocessors"
774 depends on X86_UP_APIC
776 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
777 SMP-capable replacement for PC-style interrupt controllers. Most
778 SMP systems and many recent uniprocessor systems have one.
780 If you have a single-CPU system with an IO-APIC, you can say Y here
781 to use it. If you say Y here even though your machine doesn't have
782 an IO-APIC, then the kernel will still run with no slowdown at all.
784 config X86_LOCAL_APIC
786 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
790 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
792 config X86_VISWS_APIC
794 depends on X86_32 && X86_VISWS
796 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
797 bool "Reroute for broken boot IRQs"
799 depends on X86_IO_APIC
801 This option enables a workaround that fixes a source of
802 spurious interrupts. This is recommended when threaded
803 interrupt handling is used on systems where the generation of
804 superfluous "boot interrupts" cannot be disabled.
806 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
807 entry in the chipset's IO-APIC is masked (as, e.g. the RT
808 kernel does during interrupt handling). On chipsets where this
809 boot IRQ generation cannot be disabled, this workaround keeps
810 the original IRQ line masked so that only the equivalent "boot
811 IRQ" is delivered to the CPUs. The workaround also tells the
812 kernel to set up the IRQ handler on the boot IRQ line. In this
813 way only one interrupt is delivered to the kernel. Otherwise
814 the spurious second interrupt may cause the kernel to bring
815 down (vital) interrupt lines.
817 Only affects "broken" chipsets. Interrupt sharing may be
818 increased on these systems.
821 bool "Machine Check / overheating reporting"
823 Machine Check support allows the processor to notify the
824 kernel if it detects a problem (e.g. overheating, data corruption).
825 The action the kernel takes depends on the severity of the problem,
826 ranging from warning messages to halting the machine.
830 prompt "Intel MCE features"
831 depends on X86_MCE && X86_LOCAL_APIC
833 Additional support for intel specific MCE features such as
838 prompt "AMD MCE features"
839 depends on X86_MCE && X86_LOCAL_APIC
841 Additional support for AMD specific MCE features such as
842 the DRAM Error Threshold.
844 config X86_ANCIENT_MCE
846 depends on X86_32 && X86_MCE
847 prompt "Support for old Pentium 5 / WinChip machine checks"
849 Include support for machine check handling on old Pentium 5 or WinChip
850 systems. These typically need to be enabled explicitely on the command
853 config X86_MCE_THRESHOLD
854 depends on X86_MCE_AMD || X86_MCE_INTEL
858 config X86_MCE_INJECT
860 tristate "Machine check injector support"
862 Provide support for injecting machine checks for testing purposes.
863 If you don't know what a machine check is and you don't do kernel
864 QA it is safe to say n.
866 config X86_THERMAL_VECTOR
868 depends on X86_MCE_INTEL
871 bool "Enable VM86 support" if EMBEDDED
875 This option is required by programs like DOSEMU to run 16-bit legacy
876 code on X86 processors. It also may be needed by software like
877 XFree86 to initialize some video cards via BIOS. Disabling this
878 option saves about 6k.
881 tristate "Toshiba Laptop support"
884 This adds a driver to safely access the System Management Mode of
885 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
886 not work on models with a Phoenix BIOS. The System Management Mode
887 is used to set the BIOS and power saving options on Toshiba portables.
889 For information on utilities to make use of this driver see the
890 Toshiba Linux utilities web site at:
891 <http://www.buzzard.org.uk/toshiba/>.
893 Say Y if you intend to run this kernel on a Toshiba portable.
897 tristate "Dell laptop support"
899 This adds a driver to safely access the System Management Mode
900 of the CPU on the Dell Inspiron 8000. The System Management Mode
901 is used to read cpu temperature and cooling fan status and to
902 control the fans on the I8K portables.
904 This driver has been tested only on the Inspiron 8000 but it may
905 also work with other Dell laptops. You can force loading on other
906 models by passing the parameter `force=1' to the module. Use at
909 For information on utilities to make use of this driver see the
910 I8K Linux utilities web site at:
911 <http://people.debian.org/~dz/i8k/>
913 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
916 config X86_REBOOTFIXUPS
917 bool "Enable X86 board specific fixups for reboot"
920 This enables chipset and/or board specific fixups to be done
921 in order to get reboot to work correctly. This is only needed on
922 some combinations of hardware and BIOS. The symptom, for which
923 this config is intended, is when reboot ends with a stalled/hung
926 Currently, the only fixup is for the Geode machines using
927 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
929 Say Y if you want to enable the fixup. Currently, it's safe to
930 enable this option even if you don't need it.
934 tristate "/dev/cpu/microcode - microcode support"
937 If you say Y here, you will be able to update the microcode on
938 certain Intel and AMD processors. The Intel support is for the
939 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
940 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
941 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
942 You will obviously need the actual microcode binary data itself
943 which is not shipped with the Linux kernel.
945 This option selects the general module only, you need to select
946 at least one vendor specific module as well.
948 To compile this driver as a module, choose M here: the
949 module will be called microcode.
951 config MICROCODE_INTEL
952 bool "Intel microcode patch loading support"
957 This options enables microcode patch loading support for Intel
960 For latest news and information on obtaining all the required
961 Intel ingredients for this driver, check:
962 <http://www.urbanmyth.org/microcode/>.
965 bool "AMD microcode patch loading support"
969 If you select this option, microcode patch loading support for AMD
970 processors will be enabled.
972 config MICROCODE_OLD_INTERFACE
977 tristate "/dev/cpu/*/msr - Model-specific register support"
979 This device gives privileged processes access to the x86
980 Model-Specific Registers (MSRs). It is a character device with
981 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
982 MSR accesses are directed to a specific CPU on multi-processor
986 tristate "/dev/cpu/*/cpuid - CPU information support"
988 This device gives processes access to the x86 CPUID instruction to
989 be executed on a specific processor. It is a character device
990 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
994 prompt "High Memory Support"
995 default HIGHMEM4G if !X86_NUMAQ
996 default HIGHMEM64G if X86_NUMAQ
1001 depends on !X86_NUMAQ
1003 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1004 However, the address space of 32-bit x86 processors is only 4
1005 Gigabytes large. That means that, if you have a large amount of
1006 physical memory, not all of it can be "permanently mapped" by the
1007 kernel. The physical memory that's not permanently mapped is called
1010 If you are compiling a kernel which will never run on a machine with
1011 more than 1 Gigabyte total physical RAM, answer "off" here (default
1012 choice and suitable for most users). This will result in a "3GB/1GB"
1013 split: 3GB are mapped so that each process sees a 3GB virtual memory
1014 space and the remaining part of the 4GB virtual memory space is used
1015 by the kernel to permanently map as much physical memory as
1018 If the machine has between 1 and 4 Gigabytes physical RAM, then
1021 If more than 4 Gigabytes is used then answer "64GB" here. This
1022 selection turns Intel PAE (Physical Address Extension) mode on.
1023 PAE implements 3-level paging on IA32 processors. PAE is fully
1024 supported by Linux, PAE mode is implemented on all recent Intel
1025 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1026 then the kernel will not boot on CPUs that don't support PAE!
1028 The actual amount of total physical memory will either be
1029 auto detected or can be forced by using a kernel command line option
1030 such as "mem=256M". (Try "man bootparam" or see the documentation of
1031 your boot loader (lilo or loadlin) about how to pass options to the
1032 kernel at boot time.)
1034 If unsure, say "off".
1038 depends on !X86_NUMAQ
1040 Select this if you have a 32-bit processor and between 1 and 4
1041 gigabytes of physical RAM.
1045 depends on !M386 && !M486
1048 Select this if you have a 32-bit processor and more than 4
1049 gigabytes of physical RAM.
1054 depends on EXPERIMENTAL
1055 prompt "Memory split" if EMBEDDED
1059 Select the desired split between kernel and user memory.
1061 If the address range available to the kernel is less than the
1062 physical memory installed, the remaining memory will be available
1063 as "high memory". Accessing high memory is a little more costly
1064 than low memory, as it needs to be mapped into the kernel first.
1065 Note that increasing the kernel address space limits the range
1066 available to user programs, making the address space there
1067 tighter. Selecting anything other than the default 3G/1G split
1068 will also likely make your kernel incompatible with binary-only
1071 If you are not absolutely sure what you are doing, leave this
1075 bool "3G/1G user/kernel split"
1076 config VMSPLIT_3G_OPT
1078 bool "3G/1G user/kernel split (for full 1G low memory)"
1080 bool "2G/2G user/kernel split"
1081 config VMSPLIT_2G_OPT
1083 bool "2G/2G user/kernel split (for full 2G low memory)"
1085 bool "1G/3G user/kernel split"
1090 default 0xB0000000 if VMSPLIT_3G_OPT
1091 default 0x80000000 if VMSPLIT_2G
1092 default 0x78000000 if VMSPLIT_2G_OPT
1093 default 0x40000000 if VMSPLIT_1G
1099 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1102 bool "PAE (Physical Address Extension) Support"
1103 depends on X86_32 && !HIGHMEM4G
1105 PAE is required for NX support, and furthermore enables
1106 larger swapspace support for non-overcommit purposes. It
1107 has the cost of more pagetable lookup overhead, and also
1108 consumes more pagetable space per process.
1110 config ARCH_PHYS_ADDR_T_64BIT
1111 def_bool X86_64 || X86_PAE
1113 config DIRECT_GBPAGES
1114 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1118 Allow the kernel linear mapping to use 1GB pages on CPUs that
1119 support it. This can improve the kernel's performance a tiny bit by
1120 reducing TLB pressure. If in doubt, say "Y".
1122 # Common NUMA Features
1124 bool "Numa Memory Allocation and Scheduler Support"
1126 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1127 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1129 Enable NUMA (Non Uniform Memory Access) support.
1131 The kernel will try to allocate memory used by a CPU on the
1132 local memory controller of the CPU and add some more
1133 NUMA awareness to the kernel.
1135 For 64-bit this is recommended if the system is Intel Core i7
1136 (or later), AMD Opteron, or EM64T NUMA.
1138 For 32-bit this is only needed on (rare) 32-bit-only platforms
1139 that support NUMA topologies, such as NUMAQ / Summit, or if you
1140 boot a 32-bit kernel on a 64-bit NUMA platform.
1142 Otherwise, you should say N.
1144 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1145 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1149 prompt "Old style AMD Opteron NUMA detection"
1150 depends on X86_64 && NUMA && PCI
1152 Enable K8 NUMA node topology detection. You should say Y here if
1153 you have a multi processor AMD K8 system. This uses an old
1154 method to read the NUMA configuration directly from the builtin
1155 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1156 instead, which also takes priority if both are compiled in.
1158 config X86_64_ACPI_NUMA
1160 prompt "ACPI NUMA detection"
1161 depends on X86_64 && NUMA && ACPI && PCI
1164 Enable ACPI SRAT based node topology detection.
1166 # Some NUMA nodes have memory ranges that span
1167 # other nodes. Even though a pfn is valid and
1168 # between a node's start and end pfns, it may not
1169 # reside on that node. See memmap_init_zone()
1171 config NODES_SPAN_OTHER_NODES
1173 depends on X86_64_ACPI_NUMA
1176 bool "NUMA emulation"
1177 depends on X86_64 && NUMA
1179 Enable NUMA emulation. A flat machine will be split
1180 into virtual nodes when booted with "numa=fake=N", where N is the
1181 number of nodes. This is only useful for debugging.
1184 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1186 default "9" if MAXSMP
1187 default "6" if X86_64
1188 default "4" if X86_NUMAQ
1190 depends on NEED_MULTIPLE_NODES
1192 Specify the maximum number of NUMA Nodes available on the target
1193 system. Increases memory reserved to accommodate various tables.
1195 config HAVE_ARCH_BOOTMEM
1197 depends on X86_32 && NUMA
1199 config ARCH_HAVE_MEMORY_PRESENT
1201 depends on X86_32 && DISCONTIGMEM
1203 config NEED_NODE_MEMMAP_SIZE
1205 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1207 config HAVE_ARCH_ALLOC_REMAP
1209 depends on X86_32 && NUMA
1211 config ARCH_FLATMEM_ENABLE
1213 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1215 config ARCH_DISCONTIGMEM_ENABLE
1217 depends on NUMA && X86_32
1219 config ARCH_DISCONTIGMEM_DEFAULT
1221 depends on NUMA && X86_32
1223 config ARCH_PROC_KCORE_TEXT
1225 depends on X86_64 && PROC_KCORE
1227 config ARCH_SPARSEMEM_DEFAULT
1231 config ARCH_SPARSEMEM_ENABLE
1233 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1234 select SPARSEMEM_STATIC if X86_32
1235 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1237 config ARCH_SELECT_MEMORY_MODEL
1239 depends on ARCH_SPARSEMEM_ENABLE
1241 config ARCH_MEMORY_PROBE
1243 depends on MEMORY_HOTPLUG
1245 config ILLEGAL_POINTER_VALUE
1248 default 0xdead000000000000 if X86_64
1253 bool "Allocate 3rd-level pagetables from highmem"
1254 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1256 The VM uses one page table entry for each page of physical memory.
1257 For systems with a lot of RAM, this can be wasteful of precious
1258 low memory. Setting this option will put user-space page table
1259 entries in high memory.
1261 config X86_CHECK_BIOS_CORRUPTION
1262 bool "Check for low memory corruption"
1264 Periodically check for memory corruption in low memory, which
1265 is suspected to be caused by BIOS. Even when enabled in the
1266 configuration, it is disabled at runtime. Enable it by
1267 setting "memory_corruption_check=1" on the kernel command
1268 line. By default it scans the low 64k of memory every 60
1269 seconds; see the memory_corruption_check_size and
1270 memory_corruption_check_period parameters in
1271 Documentation/kernel-parameters.txt to adjust this.
1273 When enabled with the default parameters, this option has
1274 almost no overhead, as it reserves a relatively small amount
1275 of memory and scans it infrequently. It both detects corruption
1276 and prevents it from affecting the running system.
1278 It is, however, intended as a diagnostic tool; if repeatable
1279 BIOS-originated corruption always affects the same memory,
1280 you can use memmap= to prevent the kernel from using that
1283 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1284 bool "Set the default setting of memory_corruption_check"
1285 depends on X86_CHECK_BIOS_CORRUPTION
1288 Set whether the default state of memory_corruption_check is
1291 config X86_RESERVE_LOW_64K
1292 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1295 Reserve the first 64K of physical RAM on BIOSes that are known
1296 to potentially corrupt that memory range. A numbers of BIOSes are
1297 known to utilize this area during suspend/resume, so it must not
1298 be used by the kernel.
1300 Set this to N if you are absolutely sure that you trust the BIOS
1301 to get all its memory reservations and usages right.
1303 If you have doubts about the BIOS (e.g. suspend/resume does not
1304 work or there's kernel crashes after certain hardware hotplug
1305 events) and it's not AMI or Phoenix, then you might want to enable
1306 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1307 corruption patterns.
1311 config MATH_EMULATION
1313 prompt "Math emulation" if X86_32
1315 Linux can emulate a math coprocessor (used for floating point
1316 operations) if you don't have one. 486DX and Pentium processors have
1317 a math coprocessor built in, 486SX and 386 do not, unless you added
1318 a 487DX or 387, respectively. (The messages during boot time can
1319 give you some hints here ["man dmesg"].) Everyone needs either a
1320 coprocessor or this emulation.
1322 If you don't have a math coprocessor, you need to say Y here; if you
1323 say Y here even though you have a coprocessor, the coprocessor will
1324 be used nevertheless. (This behavior can be changed with the kernel
1325 command line option "no387", which comes handy if your coprocessor
1326 is broken. Try "man bootparam" or see the documentation of your boot
1327 loader (lilo or loadlin) about how to pass options to the kernel at
1328 boot time.) This means that it is a good idea to say Y here if you
1329 intend to use this kernel on different machines.
1331 More information about the internals of the Linux math coprocessor
1332 emulation can be found in <file:arch/x86/math-emu/README>.
1334 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1335 kernel, it won't hurt.
1340 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1342 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1343 the Memory Type Range Registers (MTRRs) may be used to control
1344 processor access to memory ranges. This is most useful if you have
1345 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1346 allows bus write transfers to be combined into a larger transfer
1347 before bursting over the PCI/AGP bus. This can increase performance
1348 of image write operations 2.5 times or more. Saying Y here creates a
1349 /proc/mtrr file which may be used to manipulate your processor's
1350 MTRRs. Typically the X server should use this.
1352 This code has a reasonably generic interface so that similar
1353 control registers on other processors can be easily supported
1356 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1357 Registers (ARRs) which provide a similar functionality to MTRRs. For
1358 these, the ARRs are used to emulate the MTRRs.
1359 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1360 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1361 write-combining. All of these processors are supported by this code
1362 and it makes sense to say Y here if you have one of them.
1364 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1365 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1366 can lead to all sorts of problems, so it's good to say Y here.
1368 You can safely say Y even if your machine doesn't have MTRRs, you'll
1369 just add about 9 KB to your kernel.
1371 See <file:Documentation/x86/mtrr.txt> for more information.
1373 config MTRR_SANITIZER
1375 prompt "MTRR cleanup support"
1378 Convert MTRR layout from continuous to discrete, so X drivers can
1379 add writeback entries.
1381 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1382 The largest mtrr entry size for a continuous block can be set with
1387 config MTRR_SANITIZER_ENABLE_DEFAULT
1388 int "MTRR cleanup enable value (0-1)"
1391 depends on MTRR_SANITIZER
1393 Enable mtrr cleanup default value
1395 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1396 int "MTRR cleanup spare reg num (0-7)"
1399 depends on MTRR_SANITIZER
1401 mtrr cleanup spare entries default, it can be changed via
1402 mtrr_spare_reg_nr=N on the kernel command line.
1407 prompt "x86 PAT support" if EMBEDDED
1410 Use PAT attributes to setup page level cache control.
1412 PATs are the modern equivalents of MTRRs and are much more
1413 flexible than MTRRs.
1415 Say N here if you see bootup problems (boot crash, boot hang,
1416 spontaneous reboots) or a non-working video driver.
1420 config ARCH_USES_PG_UNCACHED
1425 bool "EFI runtime service support"
1428 This enables the kernel to use EFI runtime services that are
1429 available (such as the EFI variable services).
1431 This option is only useful on systems that have EFI firmware.
1432 In addition, you should use the latest ELILO loader available
1433 at <http://elilo.sourceforge.net> in order to take advantage
1434 of EFI runtime services. However, even with this option, the
1435 resultant kernel should continue to boot on existing non-EFI
1440 prompt "Enable seccomp to safely compute untrusted bytecode"
1442 This kernel feature is useful for number crunching applications
1443 that may need to compute untrusted bytecode during their
1444 execution. By using pipes or other transports made available to
1445 the process as file descriptors supporting the read/write
1446 syscalls, it's possible to isolate those applications in
1447 their own address space using seccomp. Once seccomp is
1448 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1449 and the task is only allowed to execute a few safe syscalls
1450 defined by each seccomp mode.
1452 If unsure, say Y. Only embedded should say N here.
1454 config CC_STACKPROTECTOR
1455 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1457 This option turns on the -fstack-protector GCC feature. This
1458 feature puts, at the beginning of functions, a canary value on
1459 the stack just before the return address, and validates
1460 the value just before actually returning. Stack based buffer
1461 overflows (that need to overwrite this return address) now also
1462 overwrite the canary, which gets detected and the attack is then
1463 neutralized via a kernel panic.
1465 This feature requires gcc version 4.2 or above, or a distribution
1466 gcc with the feature backported. Older versions are automatically
1467 detected and for those versions, this configuration option is
1468 ignored. (and a warning is printed during bootup)
1470 source kernel/Kconfig.hz
1473 bool "kexec system call"
1475 kexec is a system call that implements the ability to shutdown your
1476 current kernel, and to start another kernel. It is like a reboot
1477 but it is independent of the system firmware. And like a reboot
1478 you can start any kernel with it, not just Linux.
1480 The name comes from the similarity to the exec system call.
1482 It is an ongoing process to be certain the hardware in a machine
1483 is properly shutdown, so do not be surprised if this code does not
1484 initially work for you. It may help to enable device hotplugging
1485 support. As of this writing the exact hardware interface is
1486 strongly in flux, so no good recommendation can be made.
1489 bool "kernel crash dumps"
1490 depends on X86_64 || (X86_32 && HIGHMEM)
1492 Generate crash dump after being started by kexec.
1493 This should be normally only set in special crash dump kernels
1494 which are loaded in the main kernel with kexec-tools into
1495 a specially reserved region and then later executed after
1496 a crash by kdump/kexec. The crash dump kernel must be compiled
1497 to a memory address not used by the main kernel or BIOS using
1498 PHYSICAL_START, or it must be built as a relocatable image
1499 (CONFIG_RELOCATABLE=y).
1500 For more details see Documentation/kdump/kdump.txt
1503 bool "kexec jump (EXPERIMENTAL)"
1504 depends on EXPERIMENTAL
1505 depends on KEXEC && HIBERNATION
1507 Jump between original kernel and kexeced kernel and invoke
1508 code in physical address mode via KEXEC
1510 config PHYSICAL_START
1511 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1514 This gives the physical address where the kernel is loaded.
1516 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1517 bzImage will decompress itself to above physical address and
1518 run from there. Otherwise, bzImage will run from the address where
1519 it has been loaded by the boot loader and will ignore above physical
1522 In normal kdump cases one does not have to set/change this option
1523 as now bzImage can be compiled as a completely relocatable image
1524 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1525 address. This option is mainly useful for the folks who don't want
1526 to use a bzImage for capturing the crash dump and want to use a
1527 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1528 to be specifically compiled to run from a specific memory area
1529 (normally a reserved region) and this option comes handy.
1531 So if you are using bzImage for capturing the crash dump,
1532 leave the value here unchanged to 0x1000000 and set
1533 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1534 for capturing the crash dump change this value to start of
1535 the reserved region. In other words, it can be set based on
1536 the "X" value as specified in the "crashkernel=YM@XM"
1537 command line boot parameter passed to the panic-ed
1538 kernel. Please take a look at Documentation/kdump/kdump.txt
1539 for more details about crash dumps.
1541 Usage of bzImage for capturing the crash dump is recommended as
1542 one does not have to build two kernels. Same kernel can be used
1543 as production kernel and capture kernel. Above option should have
1544 gone away after relocatable bzImage support is introduced. But it
1545 is present because there are users out there who continue to use
1546 vmlinux for dump capture. This option should go away down the
1549 Don't change this unless you know what you are doing.
1552 bool "Build a relocatable kernel"
1555 This builds a kernel image that retains relocation information
1556 so it can be loaded someplace besides the default 1MB.
1557 The relocations tend to make the kernel binary about 10% larger,
1558 but are discarded at runtime.
1560 One use is for the kexec on panic case where the recovery kernel
1561 must live at a different physical address than the primary
1564 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1565 it has been loaded at and the compile time physical address
1566 (CONFIG_PHYSICAL_START) is ignored.
1568 # Relocation on x86-32 needs some additional build support
1569 config X86_NEED_RELOCS
1571 depends on X86_32 && RELOCATABLE
1573 config PHYSICAL_ALIGN
1575 prompt "Alignment value to which kernel should be aligned" if X86_32
1577 range 0x2000 0x1000000
1579 This value puts the alignment restrictions on physical address
1580 where kernel is loaded and run from. Kernel is compiled for an
1581 address which meets above alignment restriction.
1583 If bootloader loads the kernel at a non-aligned address and
1584 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1585 address aligned to above value and run from there.
1587 If bootloader loads the kernel at a non-aligned address and
1588 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1589 load address and decompress itself to the address it has been
1590 compiled for and run from there. The address for which kernel is
1591 compiled already meets above alignment restrictions. Hence the
1592 end result is that kernel runs from a physical address meeting
1593 above alignment restrictions.
1595 Don't change this unless you know what you are doing.
1598 bool "Support for hot-pluggable CPUs"
1599 depends on SMP && HOTPLUG
1601 Say Y here to allow turning CPUs off and on. CPUs can be
1602 controlled through /sys/devices/system/cpu.
1603 ( Note: power management support will enable this option
1604 automatically on SMP systems. )
1605 Say N if you want to disable CPU hotplug.
1609 prompt "Compat VDSO support"
1610 depends on X86_32 || IA32_EMULATION
1612 Map the 32-bit VDSO to the predictable old-style address too.
1614 Say N here if you are running a sufficiently recent glibc
1615 version (2.3.3 or later), to remove the high-mapped
1616 VDSO mapping and to exclusively use the randomized VDSO.
1621 bool "Built-in kernel command line"
1624 Allow for specifying boot arguments to the kernel at
1625 build time. On some systems (e.g. embedded ones), it is
1626 necessary or convenient to provide some or all of the
1627 kernel boot arguments with the kernel itself (that is,
1628 to not rely on the boot loader to provide them.)
1630 To compile command line arguments into the kernel,
1631 set this option to 'Y', then fill in the
1632 the boot arguments in CONFIG_CMDLINE.
1634 Systems with fully functional boot loaders (i.e. non-embedded)
1635 should leave this option set to 'N'.
1638 string "Built-in kernel command string"
1639 depends on CMDLINE_BOOL
1642 Enter arguments here that should be compiled into the kernel
1643 image and used at boot time. If the boot loader provides a
1644 command line at boot time, it is appended to this string to
1645 form the full kernel command line, when the system boots.
1647 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1648 change this behavior.
1650 In most cases, the command line (whether built-in or provided
1651 by the boot loader) should specify the device for the root
1654 config CMDLINE_OVERRIDE
1655 bool "Built-in command line overrides boot loader arguments"
1657 depends on CMDLINE_BOOL
1659 Set this option to 'Y' to have the kernel ignore the boot loader
1660 command line, and use ONLY the built-in command line.
1662 This is used to work around broken boot loaders. This should
1663 be set to 'N' under normal conditions.
1667 config ARCH_ENABLE_MEMORY_HOTPLUG
1669 depends on X86_64 || (X86_32 && HIGHMEM)
1671 config ARCH_ENABLE_MEMORY_HOTREMOVE
1673 depends on MEMORY_HOTPLUG
1675 config HAVE_ARCH_EARLY_PFN_TO_NID
1679 menu "Power management and ACPI options"
1681 config ARCH_HIBERNATION_HEADER
1683 depends on X86_64 && HIBERNATION
1685 source "kernel/power/Kconfig"
1687 source "drivers/acpi/Kconfig"
1689 source "drivers/sfi/Kconfig"
1694 depends on APM || APM_MODULE
1697 tristate "APM (Advanced Power Management) BIOS support"
1698 depends on X86_32 && PM_SLEEP
1700 APM is a BIOS specification for saving power using several different
1701 techniques. This is mostly useful for battery powered laptops with
1702 APM compliant BIOSes. If you say Y here, the system time will be
1703 reset after a RESUME operation, the /proc/apm device will provide
1704 battery status information, and user-space programs will receive
1705 notification of APM "events" (e.g. battery status change).
1707 If you select "Y" here, you can disable actual use of the APM
1708 BIOS by passing the "apm=off" option to the kernel at boot time.
1710 Note that the APM support is almost completely disabled for
1711 machines with more than one CPU.
1713 In order to use APM, you will need supporting software. For location
1714 and more information, read <file:Documentation/power/pm.txt> and the
1715 Battery Powered Linux mini-HOWTO, available from
1716 <http://www.tldp.org/docs.html#howto>.
1718 This driver does not spin down disk drives (see the hdparm(8)
1719 manpage ("man 8 hdparm") for that), and it doesn't turn off
1720 VESA-compliant "green" monitors.
1722 This driver does not support the TI 4000M TravelMate and the ACER
1723 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1724 desktop machines also don't have compliant BIOSes, and this driver
1725 may cause those machines to panic during the boot phase.
1727 Generally, if you don't have a battery in your machine, there isn't
1728 much point in using this driver and you should say N. If you get
1729 random kernel OOPSes or reboots that don't seem to be related to
1730 anything, try disabling/enabling this option (or disabling/enabling
1733 Some other things you should try when experiencing seemingly random,
1736 1) make sure that you have enough swap space and that it is
1738 2) pass the "no-hlt" option to the kernel
1739 3) switch on floating point emulation in the kernel and pass
1740 the "no387" option to the kernel
1741 4) pass the "floppy=nodma" option to the kernel
1742 5) pass the "mem=4M" option to the kernel (thereby disabling
1743 all but the first 4 MB of RAM)
1744 6) make sure that the CPU is not over clocked.
1745 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1746 8) disable the cache from your BIOS settings
1747 9) install a fan for the video card or exchange video RAM
1748 10) install a better fan for the CPU
1749 11) exchange RAM chips
1750 12) exchange the motherboard.
1752 To compile this driver as a module, choose M here: the
1753 module will be called apm.
1757 config APM_IGNORE_USER_SUSPEND
1758 bool "Ignore USER SUSPEND"
1760 This option will ignore USER SUSPEND requests. On machines with a
1761 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1762 series notebooks, it is necessary to say Y because of a BIOS bug.
1764 config APM_DO_ENABLE
1765 bool "Enable PM at boot time"
1767 Enable APM features at boot time. From page 36 of the APM BIOS
1768 specification: "When disabled, the APM BIOS does not automatically
1769 power manage devices, enter the Standby State, enter the Suspend
1770 State, or take power saving steps in response to CPU Idle calls."
1771 This driver will make CPU Idle calls when Linux is idle (unless this
1772 feature is turned off -- see "Do CPU IDLE calls", below). This
1773 should always save battery power, but more complicated APM features
1774 will be dependent on your BIOS implementation. You may need to turn
1775 this option off if your computer hangs at boot time when using APM
1776 support, or if it beeps continuously instead of suspending. Turn
1777 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1778 T400CDT. This is off by default since most machines do fine without
1782 bool "Make CPU Idle calls when idle"
1784 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1785 On some machines, this can activate improved power savings, such as
1786 a slowed CPU clock rate, when the machine is idle. These idle calls
1787 are made after the idle loop has run for some length of time (e.g.,
1788 333 mS). On some machines, this will cause a hang at boot time or
1789 whenever the CPU becomes idle. (On machines with more than one CPU,
1790 this option does nothing.)
1792 config APM_DISPLAY_BLANK
1793 bool "Enable console blanking using APM"
1795 Enable console blanking using the APM. Some laptops can use this to
1796 turn off the LCD backlight when the screen blanker of the Linux
1797 virtual console blanks the screen. Note that this is only used by
1798 the virtual console screen blanker, and won't turn off the backlight
1799 when using the X Window system. This also doesn't have anything to
1800 do with your VESA-compliant power-saving monitor. Further, this
1801 option doesn't work for all laptops -- it might not turn off your
1802 backlight at all, or it might print a lot of errors to the console,
1803 especially if you are using gpm.
1805 config APM_ALLOW_INTS
1806 bool "Allow interrupts during APM BIOS calls"
1808 Normally we disable external interrupts while we are making calls to
1809 the APM BIOS as a measure to lessen the effects of a badly behaving
1810 BIOS implementation. The BIOS should reenable interrupts if it
1811 needs to. Unfortunately, some BIOSes do not -- especially those in
1812 many of the newer IBM Thinkpads. If you experience hangs when you
1813 suspend, try setting this to Y. Otherwise, say N.
1817 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1819 source "drivers/cpuidle/Kconfig"
1821 source "drivers/idle/Kconfig"
1826 menu "Bus options (PCI etc.)"
1831 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1833 Find out whether you have a PCI motherboard. PCI is the name of a
1834 bus system, i.e. the way the CPU talks to the other stuff inside
1835 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1836 VESA. If you have PCI, say Y, otherwise N.
1839 prompt "PCI access mode"
1840 depends on X86_32 && PCI
1843 On PCI systems, the BIOS can be used to detect the PCI devices and
1844 determine their configuration. However, some old PCI motherboards
1845 have BIOS bugs and may crash if this is done. Also, some embedded
1846 PCI-based systems don't have any BIOS at all. Linux can also try to
1847 detect the PCI hardware directly without using the BIOS.
1849 With this option, you can specify how Linux should detect the
1850 PCI devices. If you choose "BIOS", the BIOS will be used,
1851 if you choose "Direct", the BIOS won't be used, and if you
1852 choose "MMConfig", then PCI Express MMCONFIG will be used.
1853 If you choose "Any", the kernel will try MMCONFIG, then the
1854 direct access method and falls back to the BIOS if that doesn't
1855 work. If unsure, go with the default, which is "Any".
1860 config PCI_GOMMCONFIG
1877 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1879 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1882 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1886 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1890 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1897 bool "Support mmconfig PCI config space access"
1898 depends on X86_64 && PCI && ACPI
1901 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1902 depends on PCI_MSI && ACPI && EXPERIMENTAL
1904 DMA remapping (DMAR) devices support enables independent address
1905 translations for Direct Memory Access (DMA) from devices.
1906 These DMA remapping devices are reported via ACPI tables
1907 and include PCI device scope covered by these DMA
1910 config DMAR_DEFAULT_ON
1912 prompt "Enable DMA Remapping Devices by default"
1915 Selecting this option will enable a DMAR device at boot time if
1916 one is found. If this option is not selected, DMAR support can
1917 be enabled by passing intel_iommu=on to the kernel. It is
1918 recommended you say N here while the DMAR code remains
1921 config DMAR_BROKEN_GFX_WA
1923 prompt "Workaround broken graphics drivers (going away soon)"
1924 depends on DMAR && BROKEN
1926 Current Graphics drivers tend to use physical address
1927 for DMA and avoid using DMA APIs. Setting this config
1928 option permits the IOMMU driver to set a unity map for
1929 all the OS-visible memory. Hence the driver can continue
1930 to use physical addresses for DMA, at least until this
1931 option is removed in the 2.6.32 kernel.
1933 config DMAR_FLOPPY_WA
1937 Floppy disk drivers are known to bypass DMA API calls
1938 thereby failing to work when IOMMU is enabled. This
1939 workaround will setup a 1:1 mapping for the first
1940 16MiB to make floppy (an ISA device) work.
1943 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1944 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1946 Supports Interrupt remapping for IO-APIC and MSI devices.
1947 To use x2apic mode in the CPU's which support x2APIC enhancements or
1948 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1950 source "drivers/pci/pcie/Kconfig"
1952 source "drivers/pci/Kconfig"
1954 # x86_64 have no ISA slots, but do have ISA-style DMA.
1963 Find out whether you have ISA slots on your motherboard. ISA is the
1964 name of a bus system, i.e. the way the CPU talks to the other stuff
1965 inside your box. Other bus systems are PCI, EISA, MicroChannel
1966 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1967 newer boards don't support it. If you have ISA, say Y, otherwise N.
1973 The Extended Industry Standard Architecture (EISA) bus was
1974 developed as an open alternative to the IBM MicroChannel bus.
1976 The EISA bus provided some of the features of the IBM MicroChannel
1977 bus while maintaining backward compatibility with cards made for
1978 the older ISA bus. The EISA bus saw limited use between 1988 and
1979 1995 when it was made obsolete by the PCI bus.
1981 Say Y here if you are building a kernel for an EISA-based machine.
1985 source "drivers/eisa/Kconfig"
1990 MicroChannel Architecture is found in some IBM PS/2 machines and
1991 laptops. It is a bus system similar to PCI or ISA. See
1992 <file:Documentation/mca.txt> (and especially the web page given
1993 there) before attempting to build an MCA bus kernel.
1995 source "drivers/mca/Kconfig"
1998 tristate "NatSemi SCx200 support"
2000 This provides basic support for National Semiconductor's
2001 (now AMD's) Geode processors. The driver probes for the
2002 PCI-IDs of several on-chip devices, so its a good dependency
2003 for other scx200_* drivers.
2005 If compiled as a module, the driver is named scx200.
2007 config SCx200HR_TIMER
2008 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2009 depends on SCx200 && GENERIC_TIME
2012 This driver provides a clocksource built upon the on-chip
2013 27MHz high-resolution timer. Its also a workaround for
2014 NSC Geode SC-1100's buggy TSC, which loses time when the
2015 processor goes idle (as is done by the scheduler). The
2016 other workaround is idle=poll boot option.
2019 bool "One Laptop Per Child support"
2023 Add support for detecting the unique features of the OLPC
2030 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2032 source "drivers/pcmcia/Kconfig"
2034 source "drivers/pci/hotplug/Kconfig"
2039 menu "Executable file formats / Emulations"
2041 source "fs/Kconfig.binfmt"
2043 config IA32_EMULATION
2044 bool "IA32 Emulation"
2046 select COMPAT_BINFMT_ELF
2048 Include code to run 32-bit programs under a 64-bit kernel. You should
2049 likely turn this on, unless you're 100% sure that you don't have any
2050 32-bit programs left.
2053 tristate "IA32 a.out support"
2054 depends on IA32_EMULATION
2056 Support old a.out binaries in the 32bit emulation.
2060 depends on IA32_EMULATION
2062 config COMPAT_FOR_U64_ALIGNMENT
2066 config SYSVIPC_COMPAT
2068 depends on COMPAT && SYSVIPC
2073 config HAVE_ATOMIC_IOMAP
2077 source "net/Kconfig"
2079 source "drivers/Kconfig"
2081 source "drivers/firmware/Kconfig"
2085 source "arch/x86/Kconfig.debug"
2087 source "security/Kconfig"
2089 source "crypto/Kconfig"
2091 source "arch/x86/kvm/Kconfig"
2093 source "lib/Kconfig"
projects / mirror_ubuntu-jammy-kernel.git / blob