3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
19 select HAVE_AOUT if X86_32
20 select HAVE_UNSTABLE_SCHED_CLOCK
23 select HAVE_PCSPKR_PLATFORM
24 select HAVE_PERF_EVENTS
26 select HAVE_IOREMAP_PROT
29 select HAVE_MEMBLOCK_NODE_MAP
30 select ARCH_DISCARD_MEMBLOCK
31 select ARCH_WANT_OPTIONAL_GPIOLIB
32 select ARCH_WANT_FRAME_POINTERS
34 select HAVE_KRETPROBES
36 select HAVE_FTRACE_MCOUNT_RECORD
37 select HAVE_C_RECORDMCOUNT
38 select HAVE_DYNAMIC_FTRACE
39 select HAVE_FUNCTION_TRACER
40 select HAVE_FUNCTION_GRAPH_TRACER
41 select HAVE_FUNCTION_GRAPH_FP_TEST
42 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
43 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
44 select HAVE_SYSCALL_TRACEPOINTS
47 select HAVE_ARCH_TRACEHOOK
48 select HAVE_GENERIC_DMA_COHERENT if X86_32
49 select HAVE_EFFICIENT_UNALIGNED_ACCESS
50 select USER_STACKTRACE_SUPPORT
51 select HAVE_REGS_AND_STACK_ACCESS_API
52 select HAVE_DMA_API_DEBUG
53 select HAVE_KERNEL_GZIP
54 select HAVE_KERNEL_BZIP2
55 select HAVE_KERNEL_LZMA
57 select HAVE_KERNEL_LZO
58 select HAVE_HW_BREAKPOINT
59 select HAVE_MIXED_BREAKPOINTS_REGS
61 select HAVE_PERF_EVENTS_NMI
63 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
64 select HAVE_CMPXCHG_LOCAL if !M386
65 select HAVE_CMPXCHG_DOUBLE
66 select HAVE_ARCH_KMEMCHECK
67 select HAVE_USER_RETURN_NOTIFIER
68 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
69 select HAVE_ARCH_JUMP_LABEL
70 select HAVE_TEXT_POKE_SMP
71 select HAVE_GENERIC_HARDIRQS
72 select HAVE_SPARSE_IRQ
74 select GENERIC_FIND_FIRST_BIT
75 select GENERIC_IRQ_PROBE
76 select GENERIC_PENDING_IRQ if SMP
77 select GENERIC_IRQ_SHOW
78 select GENERIC_CLOCKEVENTS_MIN_ADJUST
79 select IRQ_FORCED_THREADING
80 select USE_GENERIC_SMP_HELPERS if SMP
81 select HAVE_BPF_JIT if (X86_64 && NET)
83 select ARCH_HAVE_NMI_SAFE_CMPXCHG
85 select DCACHE_WORD_ACCESS if !DEBUG_PAGEALLOC
87 config INSTRUCTION_DECODER
88 def_bool (KPROBES || PERF_EVENTS)
92 default "elf32-i386" if X86_32
93 default "elf64-x86-64" if X86_64
97 default "arch/x86/configs/i386_defconfig" if X86_32
98 default "arch/x86/configs/x86_64_defconfig" if X86_64
100 config GENERIC_CMOS_UPDATE
103 config CLOCKSOURCE_WATCHDOG
106 config GENERIC_CLOCKEVENTS
109 config ARCH_CLOCKSOURCE_DATA
113 config GENERIC_CLOCKEVENTS_BROADCAST
115 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
117 config LOCKDEP_SUPPORT
120 config STACKTRACE_SUPPORT
123 config HAVE_LATENCYTOP_SUPPORT
132 config NEED_DMA_MAP_STATE
133 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
135 config NEED_SG_DMA_LENGTH
138 config GENERIC_ISA_DMA
144 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
146 config GENERIC_BUG_RELATIVE_POINTERS
149 config GENERIC_HWEIGHT
155 config ARCH_MAY_HAVE_PC_FDC
158 config RWSEM_GENERIC_SPINLOCK
161 config RWSEM_XCHGADD_ALGORITHM
164 config ARCH_HAS_CPU_IDLE_WAIT
167 config GENERIC_CALIBRATE_DELAY
170 config GENERIC_TIME_VSYSCALL
174 config ARCH_HAS_CPU_RELAX
177 config ARCH_HAS_DEFAULT_IDLE
180 config ARCH_HAS_CACHE_LINE_SIZE
183 config ARCH_HAS_CPU_AUTOPROBE
186 config HAVE_SETUP_PER_CPU_AREA
189 config NEED_PER_CPU_EMBED_FIRST_CHUNK
192 config NEED_PER_CPU_PAGE_FIRST_CHUNK
195 config ARCH_HIBERNATION_POSSIBLE
198 config ARCH_SUSPEND_POSSIBLE
209 config ARCH_SUPPORTS_OPTIMIZED_INLINING
212 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
215 config HAVE_INTEL_TXT
217 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
221 depends on X86_32 && SMP
225 depends on X86_64 && SMP
231 config X86_32_LAZY_GS
233 depends on X86_32 && !CC_STACKPROTECTOR
235 config ARCH_HWEIGHT_CFLAGS
237 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
238 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
243 config ARCH_CPU_PROBE_RELEASE
245 depends on HOTPLUG_CPU
247 source "init/Kconfig"
248 source "kernel/Kconfig.freezer"
250 menu "Processor type and features"
253 bool "DMA memory allocation support" if EXPERT
256 DMA memory allocation support allows devices with less than 32-bit
257 addressing to allocate within the first 16MB of address space.
258 Disable if no such devices will be used.
262 source "kernel/time/Kconfig"
265 bool "Symmetric multi-processing support"
267 This enables support for systems with more than one CPU. If you have
268 a system with only one CPU, like most personal computers, say N. If
269 you have a system with more than one CPU, say Y.
271 If you say N here, the kernel will run on single and multiprocessor
272 machines, but will use only one CPU of a multiprocessor machine. If
273 you say Y here, the kernel will run on many, but not all,
274 singleprocessor machines. On a singleprocessor machine, the kernel
275 will run faster if you say N here.
277 Note that if you say Y here and choose architecture "586" or
278 "Pentium" under "Processor family", the kernel will not work on 486
279 architectures. Similarly, multiprocessor kernels for the "PPro"
280 architecture may not work on all Pentium based boards.
282 People using multiprocessor machines who say Y here should also say
283 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
284 Management" code will be disabled if you say Y here.
286 See also <file:Documentation/x86/i386/IO-APIC.txt>,
287 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
288 <http://www.tldp.org/docs.html#howto>.
290 If you don't know what to do here, say N.
293 bool "Support x2apic"
294 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
296 This enables x2apic support on CPUs that have this feature.
298 This allows 32-bit apic IDs (so it can support very large systems),
299 and accesses the local apic via MSRs not via mmio.
301 If you don't know what to do here, say N.
304 bool "Enable MPS table" if ACPI
306 depends on X86_LOCAL_APIC
308 For old smp systems that do not have proper acpi support. Newer systems
309 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
312 bool "Support for big SMP systems with more than 8 CPUs"
313 depends on X86_32 && SMP
315 This option is needed for the systems that have more than 8 CPUs
318 config X86_EXTENDED_PLATFORM
319 bool "Support for extended (non-PC) x86 platforms"
322 If you disable this option then the kernel will only support
323 standard PC platforms. (which covers the vast majority of
326 If you enable this option then you'll be able to select support
327 for the following (non-PC) 32 bit x86 platforms:
331 SGI 320/540 (Visual Workstation)
332 Summit/EXA (IBM x440)
333 Unisys ES7000 IA32 series
334 Moorestown MID devices
336 If you have one of these systems, or if you want to build a
337 generic distribution kernel, say Y here - otherwise say N.
341 config X86_EXTENDED_PLATFORM
342 bool "Support for extended (non-PC) x86 platforms"
345 If you disable this option then the kernel will only support
346 standard PC platforms. (which covers the vast majority of
349 If you enable this option then you'll be able to select support
350 for the following (non-PC) 64 bit x86 platforms:
355 If you have one of these systems, or if you want to build a
356 generic distribution kernel, say Y here - otherwise say N.
358 # This is an alphabetically sorted list of 64 bit extended platforms
359 # Please maintain the alphabetic order if and when there are additions
361 bool "Numascale NumaChip"
363 depends on X86_EXTENDED_PLATFORM
366 depends on X86_X2APIC
368 Adds support for Numascale NumaChip large-SMP systems. Needed to
369 enable more than ~168 cores.
370 If you don't have one of these, you should say N here.
374 select PARAVIRT_GUEST
376 depends on X86_64 && PCI
377 depends on X86_EXTENDED_PLATFORM
379 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
380 supposed to run on these EM64T-based machines. Only choose this option
381 if you have one of these machines.
384 bool "SGI Ultraviolet"
386 depends on X86_EXTENDED_PLATFORM
388 depends on X86_X2APIC
390 This option is needed in order to support SGI Ultraviolet systems.
391 If you don't have one of these, you should say N here.
393 # Following is an alphabetically sorted list of 32 bit extended platforms
394 # Please maintain the alphabetic order if and when there are additions
397 bool "CE4100 TV platform"
399 depends on PCI_GODIRECT
401 depends on X86_EXTENDED_PLATFORM
402 select X86_REBOOTFIXUPS
404 select OF_EARLY_FLATTREE
406 Select for the Intel CE media processor (CE4100) SOC.
407 This option compiles in support for the CE4100 SOC for settop
408 boxes and media devices.
410 config X86_WANT_INTEL_MID
411 bool "Intel MID platform support"
413 depends on X86_EXTENDED_PLATFORM
415 Select to build a kernel capable of supporting Intel MID platform
416 systems which do not have the PCI legacy interfaces (Moorestown,
417 Medfield). If you are building for a PC class system say N here.
419 if X86_WANT_INTEL_MID
425 bool "Moorestown MID platform"
428 depends on X86_IO_APIC
436 select X86_PLATFORM_DEVICES
438 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
439 Internet Device(MID) platform. Moorestown consists of two chips:
440 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
441 Unlike standard x86 PCs, Moorestown does not have many legacy devices
442 nor standard legacy replacement devices/features. e.g. Moorestown does
443 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
446 bool "Medfield MID platform"
449 depends on X86_IO_APIC
457 select X86_PLATFORM_DEVICES
459 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
460 Internet Device(MID) platform.
461 Unlike standard x86 PCs, Medfield does not have many legacy devices
462 nor standard legacy replacement devices/features. e.g. Medfield does
463 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
468 bool "RDC R-321x SoC"
470 depends on X86_EXTENDED_PLATFORM
472 select X86_REBOOTFIXUPS
474 This option is needed for RDC R-321x system-on-chip, also known
476 If you don't have one of these chips, you should say N here.
478 config X86_32_NON_STANDARD
479 bool "Support non-standard 32-bit SMP architectures"
480 depends on X86_32 && SMP
481 depends on X86_EXTENDED_PLATFORM
483 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
484 subarchitectures. It is intended for a generic binary kernel.
485 if you select them all, kernel will probe it one by one. and will
488 # Alphabetically sorted list of Non standard 32 bit platforms
491 bool "NUMAQ (IBM/Sequent)"
492 depends on X86_32_NON_STANDARD
497 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
498 NUMA multiquad box. This changes the way that processors are
499 bootstrapped, and uses Clustered Logical APIC addressing mode instead
500 of Flat Logical. You will need a new lynxer.elf file to flash your
501 firmware with - send email to <Martin.Bligh@us.ibm.com>.
503 config X86_SUPPORTS_MEMORY_FAILURE
505 # MCE code calls memory_failure():
507 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
508 depends on !X86_NUMAQ
509 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
510 depends on X86_64 || !SPARSEMEM
511 select ARCH_SUPPORTS_MEMORY_FAILURE
514 bool "SGI 320/540 (Visual Workstation)"
515 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
516 depends on X86_32_NON_STANDARD
518 The SGI Visual Workstation series is an IA32-based workstation
519 based on SGI systems chips with some legacy PC hardware attached.
521 Say Y here to create a kernel to run on the SGI 320 or 540.
523 A kernel compiled for the Visual Workstation will run on general
524 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
527 bool "Summit/EXA (IBM x440)"
528 depends on X86_32_NON_STANDARD
530 This option is needed for IBM systems that use the Summit/EXA chipset.
531 In particular, it is needed for the x440.
534 bool "Unisys ES7000 IA32 series"
535 depends on X86_32_NON_STANDARD && X86_BIGSMP
537 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
538 supposed to run on an IA32-based Unisys ES7000 system.
541 tristate "Eurobraille/Iris poweroff module"
544 The Iris machines from EuroBraille do not have APM or ACPI support
545 to shut themselves down properly. A special I/O sequence is
546 needed to do so, which is what this module does at
549 This is only for Iris machines from EuroBraille.
553 config SCHED_OMIT_FRAME_POINTER
555 prompt "Single-depth WCHAN output"
558 Calculate simpler /proc/<PID>/wchan values. If this option
559 is disabled then wchan values will recurse back to the
560 caller function. This provides more accurate wchan values,
561 at the expense of slightly more scheduling overhead.
563 If in doubt, say "Y".
565 menuconfig PARAVIRT_GUEST
566 bool "Paravirtualized guest support"
568 Say Y here to get to see options related to running Linux under
569 various hypervisors. This option alone does not add any kernel code.
571 If you say N, all options in this submenu will be skipped and disabled.
575 config PARAVIRT_TIME_ACCOUNTING
576 bool "Paravirtual steal time accounting"
580 Select this option to enable fine granularity task steal time
581 accounting. Time spent executing other tasks in parallel with
582 the current vCPU is discounted from the vCPU power. To account for
583 that, there can be a small performance impact.
585 If in doubt, say N here.
587 source "arch/x86/xen/Kconfig"
590 bool "KVM paravirtualized clock"
592 select PARAVIRT_CLOCK
594 Turning on this option will allow you to run a paravirtualized clock
595 when running over the KVM hypervisor. Instead of relying on a PIT
596 (or probably other) emulation by the underlying device model, the host
597 provides the guest with timing infrastructure such as time of day, and
601 bool "KVM Guest support"
604 This option enables various optimizations for running under the KVM
607 source "arch/x86/lguest/Kconfig"
610 bool "Enable paravirtualization code"
612 This changes the kernel so it can modify itself when it is run
613 under a hypervisor, potentially improving performance significantly
614 over full virtualization. However, when run without a hypervisor
615 the kernel is theoretically slower and slightly larger.
617 config PARAVIRT_SPINLOCKS
618 bool "Paravirtualization layer for spinlocks"
619 depends on PARAVIRT && SMP && EXPERIMENTAL
621 Paravirtualized spinlocks allow a pvops backend to replace the
622 spinlock implementation with something virtualization-friendly
623 (for example, block the virtual CPU rather than spinning).
625 Unfortunately the downside is an up to 5% performance hit on
626 native kernels, with various workloads.
628 If you are unsure how to answer this question, answer N.
630 config PARAVIRT_CLOCK
635 config PARAVIRT_DEBUG
636 bool "paravirt-ops debugging"
637 depends on PARAVIRT && DEBUG_KERNEL
639 Enable to debug paravirt_ops internals. Specifically, BUG if
640 a paravirt_op is missing when it is called.
648 This option adds a kernel parameter 'memtest', which allows memtest
650 memtest=0, mean disabled; -- default
651 memtest=1, mean do 1 test pattern;
653 memtest=4, mean do 4 test patterns.
654 If you are unsure how to answer this question, answer N.
656 config X86_SUMMIT_NUMA
658 depends on X86_32 && NUMA && X86_32_NON_STANDARD
660 config X86_CYCLONE_TIMER
662 depends on X86_SUMMIT
664 source "arch/x86/Kconfig.cpu"
668 prompt "HPET Timer Support" if X86_32
670 Use the IA-PC HPET (High Precision Event Timer) to manage
671 time in preference to the PIT and RTC, if a HPET is
673 HPET is the next generation timer replacing legacy 8254s.
674 The HPET provides a stable time base on SMP
675 systems, unlike the TSC, but it is more expensive to access,
676 as it is off-chip. You can find the HPET spec at
677 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
679 You can safely choose Y here. However, HPET will only be
680 activated if the platform and the BIOS support this feature.
681 Otherwise the 8254 will be used for timing services.
683 Choose N to continue using the legacy 8254 timer.
685 config HPET_EMULATE_RTC
687 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
690 def_bool y if X86_INTEL_MID
691 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
693 depends on X86_INTEL_MID && SFI
695 APB timer is the replacement for 8254, HPET on X86 MID platforms.
696 The APBT provides a stable time base on SMP
697 systems, unlike the TSC, but it is more expensive to access,
698 as it is off-chip. APB timers are always running regardless of CPU
699 C states, they are used as per CPU clockevent device when possible.
701 # Mark as expert because too many people got it wrong.
702 # The code disables itself when not needed.
705 bool "Enable DMI scanning" if EXPERT
707 Enabled scanning of DMI to identify machine quirks. Say Y
708 here unless you have verified that your setup is not
709 affected by entries in the DMI blacklist. Required by PNP
713 bool "GART IOMMU support" if EXPERT
716 depends on X86_64 && PCI && AMD_NB
718 Support for full DMA access of devices with 32bit memory access only
719 on systems with more than 3GB. This is usually needed for USB,
720 sound, many IDE/SATA chipsets and some other devices.
721 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
722 based hardware IOMMU and a software bounce buffer based IOMMU used
723 on Intel systems and as fallback.
724 The code is only active when needed (enough memory and limited
725 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
729 bool "IBM Calgary IOMMU support"
731 depends on X86_64 && PCI && EXPERIMENTAL
733 Support for hardware IOMMUs in IBM's xSeries x366 and x460
734 systems. Needed to run systems with more than 3GB of memory
735 properly with 32-bit PCI devices that do not support DAC
736 (Double Address Cycle). Calgary also supports bus level
737 isolation, where all DMAs pass through the IOMMU. This
738 prevents them from going anywhere except their intended
739 destination. This catches hard-to-find kernel bugs and
740 mis-behaving drivers and devices that do not use the DMA-API
741 properly to set up their DMA buffers. The IOMMU can be
742 turned off at boot time with the iommu=off parameter.
743 Normally the kernel will make the right choice by itself.
746 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
748 prompt "Should Calgary be enabled by default?"
749 depends on CALGARY_IOMMU
751 Should Calgary be enabled by default? if you choose 'y', Calgary
752 will be used (if it exists). If you choose 'n', Calgary will not be
753 used even if it exists. If you choose 'n' and would like to use
754 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
757 # need this always selected by IOMMU for the VIA workaround
761 Support for software bounce buffers used on x86-64 systems
762 which don't have a hardware IOMMU (e.g. the current generation
763 of Intel's x86-64 CPUs). Using this PCI devices which can only
764 access 32-bits of memory can be used on systems with more than
765 3 GB of memory. If unsure, say Y.
768 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
771 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
772 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
773 select CPUMASK_OFFSTACK
775 Enable maximum number of CPUS and NUMA Nodes for this architecture.
779 int "Maximum number of CPUs" if SMP && !MAXSMP
780 range 2 8 if SMP && X86_32 && !X86_BIGSMP
781 range 2 512 if SMP && !MAXSMP
783 default "4096" if MAXSMP
784 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
787 This allows you to specify the maximum number of CPUs which this
788 kernel will support. The maximum supported value is 512 and the
789 minimum value which makes sense is 2.
791 This is purely to save memory - each supported CPU adds
792 approximately eight kilobytes to the kernel image.
795 bool "SMT (Hyperthreading) scheduler support"
798 SMT scheduler support improves the CPU scheduler's decision making
799 when dealing with Intel Pentium 4 chips with HyperThreading at a
800 cost of slightly increased overhead in some places. If unsure say
805 prompt "Multi-core scheduler support"
808 Multi-core scheduler support improves the CPU scheduler's decision
809 making when dealing with multi-core CPU chips at a cost of slightly
810 increased overhead in some places. If unsure say N here.
812 config IRQ_TIME_ACCOUNTING
813 bool "Fine granularity task level IRQ time accounting"
816 Select this option to enable fine granularity task irq time
817 accounting. This is done by reading a timestamp on each
818 transitions between softirq and hardirq state, so there can be a
819 small performance impact.
821 If in doubt, say N here.
823 source "kernel/Kconfig.preempt"
826 bool "Local APIC support on uniprocessors"
827 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
829 A local APIC (Advanced Programmable Interrupt Controller) is an
830 integrated interrupt controller in the CPU. If you have a single-CPU
831 system which has a processor with a local APIC, you can say Y here to
832 enable and use it. If you say Y here even though your machine doesn't
833 have a local APIC, then the kernel will still run with no slowdown at
834 all. The local APIC supports CPU-generated self-interrupts (timer,
835 performance counters), and the NMI watchdog which detects hard
839 bool "IO-APIC support on uniprocessors"
840 depends on X86_UP_APIC
842 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
843 SMP-capable replacement for PC-style interrupt controllers. Most
844 SMP systems and many recent uniprocessor systems have one.
846 If you have a single-CPU system with an IO-APIC, you can say Y here
847 to use it. If you say Y here even though your machine doesn't have
848 an IO-APIC, then the kernel will still run with no slowdown at all.
850 config X86_LOCAL_APIC
852 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
856 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
858 config X86_VISWS_APIC
860 depends on X86_32 && X86_VISWS
862 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
863 bool "Reroute for broken boot IRQs"
864 depends on X86_IO_APIC
866 This option enables a workaround that fixes a source of
867 spurious interrupts. This is recommended when threaded
868 interrupt handling is used on systems where the generation of
869 superfluous "boot interrupts" cannot be disabled.
871 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
872 entry in the chipset's IO-APIC is masked (as, e.g. the RT
873 kernel does during interrupt handling). On chipsets where this
874 boot IRQ generation cannot be disabled, this workaround keeps
875 the original IRQ line masked so that only the equivalent "boot
876 IRQ" is delivered to the CPUs. The workaround also tells the
877 kernel to set up the IRQ handler on the boot IRQ line. In this
878 way only one interrupt is delivered to the kernel. Otherwise
879 the spurious second interrupt may cause the kernel to bring
880 down (vital) interrupt lines.
882 Only affects "broken" chipsets. Interrupt sharing may be
883 increased on these systems.
886 bool "Machine Check / overheating reporting"
888 Machine Check support allows the processor to notify the
889 kernel if it detects a problem (e.g. overheating, data corruption).
890 The action the kernel takes depends on the severity of the problem,
891 ranging from warning messages to halting the machine.
895 prompt "Intel MCE features"
896 depends on X86_MCE && X86_LOCAL_APIC
898 Additional support for intel specific MCE features such as
903 prompt "AMD MCE features"
904 depends on X86_MCE && X86_LOCAL_APIC
906 Additional support for AMD specific MCE features such as
907 the DRAM Error Threshold.
909 config X86_ANCIENT_MCE
910 bool "Support for old Pentium 5 / WinChip machine checks"
911 depends on X86_32 && X86_MCE
913 Include support for machine check handling on old Pentium 5 or WinChip
914 systems. These typically need to be enabled explicitely on the command
917 config X86_MCE_THRESHOLD
918 depends on X86_MCE_AMD || X86_MCE_INTEL
921 config X86_MCE_INJECT
923 tristate "Machine check injector support"
925 Provide support for injecting machine checks for testing purposes.
926 If you don't know what a machine check is and you don't do kernel
927 QA it is safe to say n.
929 config X86_THERMAL_VECTOR
931 depends on X86_MCE_INTEL
934 bool "Enable VM86 support" if EXPERT
938 This option is required by programs like DOSEMU to run 16-bit legacy
939 code on X86 processors. It also may be needed by software like
940 XFree86 to initialize some video cards via BIOS. Disabling this
941 option saves about 6k.
944 tristate "Toshiba Laptop support"
947 This adds a driver to safely access the System Management Mode of
948 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
949 not work on models with a Phoenix BIOS. The System Management Mode
950 is used to set the BIOS and power saving options on Toshiba portables.
952 For information on utilities to make use of this driver see the
953 Toshiba Linux utilities web site at:
954 <http://www.buzzard.org.uk/toshiba/>.
956 Say Y if you intend to run this kernel on a Toshiba portable.
960 tristate "Dell laptop support"
963 This adds a driver to safely access the System Management Mode
964 of the CPU on the Dell Inspiron 8000. The System Management Mode
965 is used to read cpu temperature and cooling fan status and to
966 control the fans on the I8K portables.
968 This driver has been tested only on the Inspiron 8000 but it may
969 also work with other Dell laptops. You can force loading on other
970 models by passing the parameter `force=1' to the module. Use at
973 For information on utilities to make use of this driver see the
974 I8K Linux utilities web site at:
975 <http://people.debian.org/~dz/i8k/>
977 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
980 config X86_REBOOTFIXUPS
981 bool "Enable X86 board specific fixups for reboot"
984 This enables chipset and/or board specific fixups to be done
985 in order to get reboot to work correctly. This is only needed on
986 some combinations of hardware and BIOS. The symptom, for which
987 this config is intended, is when reboot ends with a stalled/hung
990 Currently, the only fixup is for the Geode machines using
991 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
993 Say Y if you want to enable the fixup. Currently, it's safe to
994 enable this option even if you don't need it.
998 tristate "/dev/cpu/microcode - microcode support"
1001 If you say Y here, you will be able to update the microcode on
1002 certain Intel and AMD processors. The Intel support is for the
1003 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
1004 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
1005 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
1006 You will obviously need the actual microcode binary data itself
1007 which is not shipped with the Linux kernel.
1009 This option selects the general module only, you need to select
1010 at least one vendor specific module as well.
1012 To compile this driver as a module, choose M here: the
1013 module will be called microcode.
1015 config MICROCODE_INTEL
1016 bool "Intel microcode patch loading support"
1017 depends on MICROCODE
1021 This options enables microcode patch loading support for Intel
1024 For latest news and information on obtaining all the required
1025 Intel ingredients for this driver, check:
1026 <http://www.urbanmyth.org/microcode/>.
1028 config MICROCODE_AMD
1029 bool "AMD microcode patch loading support"
1030 depends on MICROCODE
1033 If you select this option, microcode patch loading support for AMD
1034 processors will be enabled.
1036 config MICROCODE_OLD_INTERFACE
1038 depends on MICROCODE
1041 tristate "/dev/cpu/*/msr - Model-specific register support"
1043 This device gives privileged processes access to the x86
1044 Model-Specific Registers (MSRs). It is a character device with
1045 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1046 MSR accesses are directed to a specific CPU on multi-processor
1050 tristate "/dev/cpu/*/cpuid - CPU information support"
1052 This device gives processes access to the x86 CPUID instruction to
1053 be executed on a specific processor. It is a character device
1054 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1058 prompt "High Memory Support"
1059 default HIGHMEM64G if X86_NUMAQ
1065 depends on !X86_NUMAQ
1067 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1068 However, the address space of 32-bit x86 processors is only 4
1069 Gigabytes large. That means that, if you have a large amount of
1070 physical memory, not all of it can be "permanently mapped" by the
1071 kernel. The physical memory that's not permanently mapped is called
1074 If you are compiling a kernel which will never run on a machine with
1075 more than 1 Gigabyte total physical RAM, answer "off" here (default
1076 choice and suitable for most users). This will result in a "3GB/1GB"
1077 split: 3GB are mapped so that each process sees a 3GB virtual memory
1078 space and the remaining part of the 4GB virtual memory space is used
1079 by the kernel to permanently map as much physical memory as
1082 If the machine has between 1 and 4 Gigabytes physical RAM, then
1085 If more than 4 Gigabytes is used then answer "64GB" here. This
1086 selection turns Intel PAE (Physical Address Extension) mode on.
1087 PAE implements 3-level paging on IA32 processors. PAE is fully
1088 supported by Linux, PAE mode is implemented on all recent Intel
1089 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1090 then the kernel will not boot on CPUs that don't support PAE!
1092 The actual amount of total physical memory will either be
1093 auto detected or can be forced by using a kernel command line option
1094 such as "mem=256M". (Try "man bootparam" or see the documentation of
1095 your boot loader (lilo or loadlin) about how to pass options to the
1096 kernel at boot time.)
1098 If unsure, say "off".
1102 depends on !X86_NUMAQ
1104 Select this if you have a 32-bit processor and between 1 and 4
1105 gigabytes of physical RAM.
1109 depends on !M386 && !M486
1112 Select this if you have a 32-bit processor and more than 4
1113 gigabytes of physical RAM.
1118 depends on EXPERIMENTAL
1119 prompt "Memory split" if EXPERT
1123 Select the desired split between kernel and user memory.
1125 If the address range available to the kernel is less than the
1126 physical memory installed, the remaining memory will be available
1127 as "high memory". Accessing high memory is a little more costly
1128 than low memory, as it needs to be mapped into the kernel first.
1129 Note that increasing the kernel address space limits the range
1130 available to user programs, making the address space there
1131 tighter. Selecting anything other than the default 3G/1G split
1132 will also likely make your kernel incompatible with binary-only
1135 If you are not absolutely sure what you are doing, leave this
1139 bool "3G/1G user/kernel split"
1140 config VMSPLIT_3G_OPT
1142 bool "3G/1G user/kernel split (for full 1G low memory)"
1144 bool "2G/2G user/kernel split"
1145 config VMSPLIT_2G_OPT
1147 bool "2G/2G user/kernel split (for full 2G low memory)"
1149 bool "1G/3G user/kernel split"
1154 default 0xB0000000 if VMSPLIT_3G_OPT
1155 default 0x80000000 if VMSPLIT_2G
1156 default 0x78000000 if VMSPLIT_2G_OPT
1157 default 0x40000000 if VMSPLIT_1G
1163 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1166 bool "PAE (Physical Address Extension) Support"
1167 depends on X86_32 && !HIGHMEM4G
1169 PAE is required for NX support, and furthermore enables
1170 larger swapspace support for non-overcommit purposes. It
1171 has the cost of more pagetable lookup overhead, and also
1172 consumes more pagetable space per process.
1174 config ARCH_PHYS_ADDR_T_64BIT
1175 def_bool X86_64 || X86_PAE
1177 config ARCH_DMA_ADDR_T_64BIT
1178 def_bool X86_64 || HIGHMEM64G
1180 config DIRECT_GBPAGES
1181 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1185 Allow the kernel linear mapping to use 1GB pages on CPUs that
1186 support it. This can improve the kernel's performance a tiny bit by
1187 reducing TLB pressure. If in doubt, say "Y".
1189 # Common NUMA Features
1191 bool "Numa Memory Allocation and Scheduler Support"
1193 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1194 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1196 Enable NUMA (Non Uniform Memory Access) support.
1198 The kernel will try to allocate memory used by a CPU on the
1199 local memory controller of the CPU and add some more
1200 NUMA awareness to the kernel.
1202 For 64-bit this is recommended if the system is Intel Core i7
1203 (or later), AMD Opteron, or EM64T NUMA.
1205 For 32-bit this is only needed on (rare) 32-bit-only platforms
1206 that support NUMA topologies, such as NUMAQ / Summit, or if you
1207 boot a 32-bit kernel on a 64-bit NUMA platform.
1209 Otherwise, you should say N.
1211 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1212 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1216 prompt "Old style AMD Opteron NUMA detection"
1217 depends on X86_64 && NUMA && PCI
1219 Enable AMD NUMA node topology detection. You should say Y here if
1220 you have a multi processor AMD system. This uses an old method to
1221 read the NUMA configuration directly from the builtin Northbridge
1222 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1223 which also takes priority if both are compiled in.
1225 config X86_64_ACPI_NUMA
1227 prompt "ACPI NUMA detection"
1228 depends on X86_64 && NUMA && ACPI && PCI
1231 Enable ACPI SRAT based node topology detection.
1233 # Some NUMA nodes have memory ranges that span
1234 # other nodes. Even though a pfn is valid and
1235 # between a node's start and end pfns, it may not
1236 # reside on that node. See memmap_init_zone()
1238 config NODES_SPAN_OTHER_NODES
1240 depends on X86_64_ACPI_NUMA
1243 bool "NUMA emulation"
1246 Enable NUMA emulation. A flat machine will be split
1247 into virtual nodes when booted with "numa=fake=N", where N is the
1248 number of nodes. This is only useful for debugging.
1251 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1253 default "10" if MAXSMP
1254 default "6" if X86_64
1255 default "4" if X86_NUMAQ
1257 depends on NEED_MULTIPLE_NODES
1259 Specify the maximum number of NUMA Nodes available on the target
1260 system. Increases memory reserved to accommodate various tables.
1262 config HAVE_ARCH_BOOTMEM
1264 depends on X86_32 && NUMA
1266 config HAVE_ARCH_ALLOC_REMAP
1268 depends on X86_32 && NUMA
1270 config ARCH_HAVE_MEMORY_PRESENT
1272 depends on X86_32 && DISCONTIGMEM
1274 config NEED_NODE_MEMMAP_SIZE
1276 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1278 config ARCH_FLATMEM_ENABLE
1280 depends on X86_32 && !NUMA
1282 config ARCH_DISCONTIGMEM_ENABLE
1284 depends on NUMA && X86_32
1286 config ARCH_DISCONTIGMEM_DEFAULT
1288 depends on NUMA && X86_32
1290 config ARCH_SPARSEMEM_ENABLE
1292 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1293 select SPARSEMEM_STATIC if X86_32
1294 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1296 config ARCH_SPARSEMEM_DEFAULT
1300 config ARCH_SELECT_MEMORY_MODEL
1302 depends on ARCH_SPARSEMEM_ENABLE
1304 config ARCH_MEMORY_PROBE
1306 depends on MEMORY_HOTPLUG
1308 config ARCH_PROC_KCORE_TEXT
1310 depends on X86_64 && PROC_KCORE
1312 config ILLEGAL_POINTER_VALUE
1315 default 0xdead000000000000 if X86_64
1320 bool "Allocate 3rd-level pagetables from highmem"
1323 The VM uses one page table entry for each page of physical memory.
1324 For systems with a lot of RAM, this can be wasteful of precious
1325 low memory. Setting this option will put user-space page table
1326 entries in high memory.
1328 config X86_CHECK_BIOS_CORRUPTION
1329 bool "Check for low memory corruption"
1331 Periodically check for memory corruption in low memory, which
1332 is suspected to be caused by BIOS. Even when enabled in the
1333 configuration, it is disabled at runtime. Enable it by
1334 setting "memory_corruption_check=1" on the kernel command
1335 line. By default it scans the low 64k of memory every 60
1336 seconds; see the memory_corruption_check_size and
1337 memory_corruption_check_period parameters in
1338 Documentation/kernel-parameters.txt to adjust this.
1340 When enabled with the default parameters, this option has
1341 almost no overhead, as it reserves a relatively small amount
1342 of memory and scans it infrequently. It both detects corruption
1343 and prevents it from affecting the running system.
1345 It is, however, intended as a diagnostic tool; if repeatable
1346 BIOS-originated corruption always affects the same memory,
1347 you can use memmap= to prevent the kernel from using that
1350 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1351 bool "Set the default setting of memory_corruption_check"
1352 depends on X86_CHECK_BIOS_CORRUPTION
1355 Set whether the default state of memory_corruption_check is
1358 config X86_RESERVE_LOW
1359 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1363 Specify the amount of low memory to reserve for the BIOS.
1365 The first page contains BIOS data structures that the kernel
1366 must not use, so that page must always be reserved.
1368 By default we reserve the first 64K of physical RAM, as a
1369 number of BIOSes are known to corrupt that memory range
1370 during events such as suspend/resume or monitor cable
1371 insertion, so it must not be used by the kernel.
1373 You can set this to 4 if you are absolutely sure that you
1374 trust the BIOS to get all its memory reservations and usages
1375 right. If you know your BIOS have problems beyond the
1376 default 64K area, you can set this to 640 to avoid using the
1377 entire low memory range.
1379 If you have doubts about the BIOS (e.g. suspend/resume does
1380 not work or there's kernel crashes after certain hardware
1381 hotplug events) then you might want to enable
1382 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1383 typical corruption patterns.
1385 Leave this to the default value of 64 if you are unsure.
1387 config MATH_EMULATION
1389 prompt "Math emulation" if X86_32
1391 Linux can emulate a math coprocessor (used for floating point
1392 operations) if you don't have one. 486DX and Pentium processors have
1393 a math coprocessor built in, 486SX and 386 do not, unless you added
1394 a 487DX or 387, respectively. (The messages during boot time can
1395 give you some hints here ["man dmesg"].) Everyone needs either a
1396 coprocessor or this emulation.
1398 If you don't have a math coprocessor, you need to say Y here; if you
1399 say Y here even though you have a coprocessor, the coprocessor will
1400 be used nevertheless. (This behavior can be changed with the kernel
1401 command line option "no387", which comes handy if your coprocessor
1402 is broken. Try "man bootparam" or see the documentation of your boot
1403 loader (lilo or loadlin) about how to pass options to the kernel at
1404 boot time.) This means that it is a good idea to say Y here if you
1405 intend to use this kernel on different machines.
1407 More information about the internals of the Linux math coprocessor
1408 emulation can be found in <file:arch/x86/math-emu/README>.
1410 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1411 kernel, it won't hurt.
1415 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1417 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1418 the Memory Type Range Registers (MTRRs) may be used to control
1419 processor access to memory ranges. This is most useful if you have
1420 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1421 allows bus write transfers to be combined into a larger transfer
1422 before bursting over the PCI/AGP bus. This can increase performance
1423 of image write operations 2.5 times or more. Saying Y here creates a
1424 /proc/mtrr file which may be used to manipulate your processor's
1425 MTRRs. Typically the X server should use this.
1427 This code has a reasonably generic interface so that similar
1428 control registers on other processors can be easily supported
1431 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1432 Registers (ARRs) which provide a similar functionality to MTRRs. For
1433 these, the ARRs are used to emulate the MTRRs.
1434 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1435 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1436 write-combining. All of these processors are supported by this code
1437 and it makes sense to say Y here if you have one of them.
1439 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1440 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1441 can lead to all sorts of problems, so it's good to say Y here.
1443 You can safely say Y even if your machine doesn't have MTRRs, you'll
1444 just add about 9 KB to your kernel.
1446 See <file:Documentation/x86/mtrr.txt> for more information.
1448 config MTRR_SANITIZER
1450 prompt "MTRR cleanup support"
1453 Convert MTRR layout from continuous to discrete, so X drivers can
1454 add writeback entries.
1456 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1457 The largest mtrr entry size for a continuous block can be set with
1462 config MTRR_SANITIZER_ENABLE_DEFAULT
1463 int "MTRR cleanup enable value (0-1)"
1466 depends on MTRR_SANITIZER
1468 Enable mtrr cleanup default value
1470 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1471 int "MTRR cleanup spare reg num (0-7)"
1474 depends on MTRR_SANITIZER
1476 mtrr cleanup spare entries default, it can be changed via
1477 mtrr_spare_reg_nr=N on the kernel command line.
1481 prompt "x86 PAT support" if EXPERT
1484 Use PAT attributes to setup page level cache control.
1486 PATs are the modern equivalents of MTRRs and are much more
1487 flexible than MTRRs.
1489 Say N here if you see bootup problems (boot crash, boot hang,
1490 spontaneous reboots) or a non-working video driver.
1494 config ARCH_USES_PG_UNCACHED
1500 prompt "x86 architectural random number generator" if EXPERT
1502 Enable the x86 architectural RDRAND instruction
1503 (Intel Bull Mountain technology) to generate random numbers.
1504 If supported, this is a high bandwidth, cryptographically
1505 secure hardware random number generator.
1508 bool "EFI runtime service support"
1511 This enables the kernel to use EFI runtime services that are
1512 available (such as the EFI variable services).
1514 This option is only useful on systems that have EFI firmware.
1515 In addition, you should use the latest ELILO loader available
1516 at <http://elilo.sourceforge.net> in order to take advantage
1517 of EFI runtime services. However, even with this option, the
1518 resultant kernel should continue to boot on existing non-EFI
1522 bool "EFI stub support"
1525 This kernel feature allows a bzImage to be loaded directly
1526 by EFI firmware without the use of a bootloader.
1530 prompt "Enable seccomp to safely compute untrusted bytecode"
1532 This kernel feature is useful for number crunching applications
1533 that may need to compute untrusted bytecode during their
1534 execution. By using pipes or other transports made available to
1535 the process as file descriptors supporting the read/write
1536 syscalls, it's possible to isolate those applications in
1537 their own address space using seccomp. Once seccomp is
1538 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1539 and the task is only allowed to execute a few safe syscalls
1540 defined by each seccomp mode.
1542 If unsure, say Y. Only embedded should say N here.
1544 config CC_STACKPROTECTOR
1545 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1547 This option turns on the -fstack-protector GCC feature. This
1548 feature puts, at the beginning of functions, a canary value on
1549 the stack just before the return address, and validates
1550 the value just before actually returning. Stack based buffer
1551 overflows (that need to overwrite this return address) now also
1552 overwrite the canary, which gets detected and the attack is then
1553 neutralized via a kernel panic.
1555 This feature requires gcc version 4.2 or above, or a distribution
1556 gcc with the feature backported. Older versions are automatically
1557 detected and for those versions, this configuration option is
1558 ignored. (and a warning is printed during bootup)
1560 source kernel/Kconfig.hz
1563 bool "kexec system call"
1565 kexec is a system call that implements the ability to shutdown your
1566 current kernel, and to start another kernel. It is like a reboot
1567 but it is independent of the system firmware. And like a reboot
1568 you can start any kernel with it, not just Linux.
1570 The name comes from the similarity to the exec system call.
1572 It is an ongoing process to be certain the hardware in a machine
1573 is properly shutdown, so do not be surprised if this code does not
1574 initially work for you. It may help to enable device hotplugging
1575 support. As of this writing the exact hardware interface is
1576 strongly in flux, so no good recommendation can be made.
1579 bool "kernel crash dumps"
1580 depends on X86_64 || (X86_32 && HIGHMEM)
1582 Generate crash dump after being started by kexec.
1583 This should be normally only set in special crash dump kernels
1584 which are loaded in the main kernel with kexec-tools into
1585 a specially reserved region and then later executed after
1586 a crash by kdump/kexec. The crash dump kernel must be compiled
1587 to a memory address not used by the main kernel or BIOS using
1588 PHYSICAL_START, or it must be built as a relocatable image
1589 (CONFIG_RELOCATABLE=y).
1590 For more details see Documentation/kdump/kdump.txt
1593 bool "kexec jump (EXPERIMENTAL)"
1594 depends on EXPERIMENTAL
1595 depends on KEXEC && HIBERNATION
1597 Jump between original kernel and kexeced kernel and invoke
1598 code in physical address mode via KEXEC
1600 config PHYSICAL_START
1601 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1604 This gives the physical address where the kernel is loaded.
1606 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1607 bzImage will decompress itself to above physical address and
1608 run from there. Otherwise, bzImage will run from the address where
1609 it has been loaded by the boot loader and will ignore above physical
1612 In normal kdump cases one does not have to set/change this option
1613 as now bzImage can be compiled as a completely relocatable image
1614 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1615 address. This option is mainly useful for the folks who don't want
1616 to use a bzImage for capturing the crash dump and want to use a
1617 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1618 to be specifically compiled to run from a specific memory area
1619 (normally a reserved region) and this option comes handy.
1621 So if you are using bzImage for capturing the crash dump,
1622 leave the value here unchanged to 0x1000000 and set
1623 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1624 for capturing the crash dump change this value to start of
1625 the reserved region. In other words, it can be set based on
1626 the "X" value as specified in the "crashkernel=YM@XM"
1627 command line boot parameter passed to the panic-ed
1628 kernel. Please take a look at Documentation/kdump/kdump.txt
1629 for more details about crash dumps.
1631 Usage of bzImage for capturing the crash dump is recommended as
1632 one does not have to build two kernels. Same kernel can be used
1633 as production kernel and capture kernel. Above option should have
1634 gone away after relocatable bzImage support is introduced. But it
1635 is present because there are users out there who continue to use
1636 vmlinux for dump capture. This option should go away down the
1639 Don't change this unless you know what you are doing.
1642 bool "Build a relocatable kernel"
1645 This builds a kernel image that retains relocation information
1646 so it can be loaded someplace besides the default 1MB.
1647 The relocations tend to make the kernel binary about 10% larger,
1648 but are discarded at runtime.
1650 One use is for the kexec on panic case where the recovery kernel
1651 must live at a different physical address than the primary
1654 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1655 it has been loaded at and the compile time physical address
1656 (CONFIG_PHYSICAL_START) is ignored.
1658 # Relocation on x86-32 needs some additional build support
1659 config X86_NEED_RELOCS
1661 depends on X86_32 && RELOCATABLE
1663 config PHYSICAL_ALIGN
1664 hex "Alignment value to which kernel should be aligned" if X86_32
1666 range 0x2000 0x1000000
1668 This value puts the alignment restrictions on physical address
1669 where kernel is loaded and run from. Kernel is compiled for an
1670 address which meets above alignment restriction.
1672 If bootloader loads the kernel at a non-aligned address and
1673 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1674 address aligned to above value and run from there.
1676 If bootloader loads the kernel at a non-aligned address and
1677 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1678 load address and decompress itself to the address it has been
1679 compiled for and run from there. The address for which kernel is
1680 compiled already meets above alignment restrictions. Hence the
1681 end result is that kernel runs from a physical address meeting
1682 above alignment restrictions.
1684 Don't change this unless you know what you are doing.
1687 bool "Support for hot-pluggable CPUs"
1688 depends on SMP && HOTPLUG
1690 Say Y here to allow turning CPUs off and on. CPUs can be
1691 controlled through /sys/devices/system/cpu.
1692 ( Note: power management support will enable this option
1693 automatically on SMP systems. )
1694 Say N if you want to disable CPU hotplug.
1698 prompt "Compat VDSO support"
1699 depends on X86_32 || IA32_EMULATION
1701 Map the 32-bit VDSO to the predictable old-style address too.
1703 Say N here if you are running a sufficiently recent glibc
1704 version (2.3.3 or later), to remove the high-mapped
1705 VDSO mapping and to exclusively use the randomized VDSO.
1710 bool "Built-in kernel command line"
1712 Allow for specifying boot arguments to the kernel at
1713 build time. On some systems (e.g. embedded ones), it is
1714 necessary or convenient to provide some or all of the
1715 kernel boot arguments with the kernel itself (that is,
1716 to not rely on the boot loader to provide them.)
1718 To compile command line arguments into the kernel,
1719 set this option to 'Y', then fill in the
1720 the boot arguments in CONFIG_CMDLINE.
1722 Systems with fully functional boot loaders (i.e. non-embedded)
1723 should leave this option set to 'N'.
1726 string "Built-in kernel command string"
1727 depends on CMDLINE_BOOL
1730 Enter arguments here that should be compiled into the kernel
1731 image and used at boot time. If the boot loader provides a
1732 command line at boot time, it is appended to this string to
1733 form the full kernel command line, when the system boots.
1735 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1736 change this behavior.
1738 In most cases, the command line (whether built-in or provided
1739 by the boot loader) should specify the device for the root
1742 config CMDLINE_OVERRIDE
1743 bool "Built-in command line overrides boot loader arguments"
1744 depends on CMDLINE_BOOL
1746 Set this option to 'Y' to have the kernel ignore the boot loader
1747 command line, and use ONLY the built-in command line.
1749 This is used to work around broken boot loaders. This should
1750 be set to 'N' under normal conditions.
1754 config ARCH_ENABLE_MEMORY_HOTPLUG
1756 depends on X86_64 || (X86_32 && HIGHMEM)
1758 config ARCH_ENABLE_MEMORY_HOTREMOVE
1760 depends on MEMORY_HOTPLUG
1762 config USE_PERCPU_NUMA_NODE_ID
1766 menu "Power management and ACPI options"
1768 config ARCH_HIBERNATION_HEADER
1770 depends on X86_64 && HIBERNATION
1772 source "kernel/power/Kconfig"
1774 source "drivers/acpi/Kconfig"
1776 source "drivers/sfi/Kconfig"
1783 tristate "APM (Advanced Power Management) BIOS support"
1784 depends on X86_32 && PM_SLEEP
1786 APM is a BIOS specification for saving power using several different
1787 techniques. This is mostly useful for battery powered laptops with
1788 APM compliant BIOSes. If you say Y here, the system time will be
1789 reset after a RESUME operation, the /proc/apm device will provide
1790 battery status information, and user-space programs will receive
1791 notification of APM "events" (e.g. battery status change).
1793 If you select "Y" here, you can disable actual use of the APM
1794 BIOS by passing the "apm=off" option to the kernel at boot time.
1796 Note that the APM support is almost completely disabled for
1797 machines with more than one CPU.
1799 In order to use APM, you will need supporting software. For location
1800 and more information, read <file:Documentation/power/apm-acpi.txt>
1801 and the Battery Powered Linux mini-HOWTO, available from
1802 <http://www.tldp.org/docs.html#howto>.
1804 This driver does not spin down disk drives (see the hdparm(8)
1805 manpage ("man 8 hdparm") for that), and it doesn't turn off
1806 VESA-compliant "green" monitors.
1808 This driver does not support the TI 4000M TravelMate and the ACER
1809 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1810 desktop machines also don't have compliant BIOSes, and this driver
1811 may cause those machines to panic during the boot phase.
1813 Generally, if you don't have a battery in your machine, there isn't
1814 much point in using this driver and you should say N. If you get
1815 random kernel OOPSes or reboots that don't seem to be related to
1816 anything, try disabling/enabling this option (or disabling/enabling
1819 Some other things you should try when experiencing seemingly random,
1822 1) make sure that you have enough swap space and that it is
1824 2) pass the "no-hlt" option to the kernel
1825 3) switch on floating point emulation in the kernel and pass
1826 the "no387" option to the kernel
1827 4) pass the "floppy=nodma" option to the kernel
1828 5) pass the "mem=4M" option to the kernel (thereby disabling
1829 all but the first 4 MB of RAM)
1830 6) make sure that the CPU is not over clocked.
1831 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1832 8) disable the cache from your BIOS settings
1833 9) install a fan for the video card or exchange video RAM
1834 10) install a better fan for the CPU
1835 11) exchange RAM chips
1836 12) exchange the motherboard.
1838 To compile this driver as a module, choose M here: the
1839 module will be called apm.
1843 config APM_IGNORE_USER_SUSPEND
1844 bool "Ignore USER SUSPEND"
1846 This option will ignore USER SUSPEND requests. On machines with a
1847 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1848 series notebooks, it is necessary to say Y because of a BIOS bug.
1850 config APM_DO_ENABLE
1851 bool "Enable PM at boot time"
1853 Enable APM features at boot time. From page 36 of the APM BIOS
1854 specification: "When disabled, the APM BIOS does not automatically
1855 power manage devices, enter the Standby State, enter the Suspend
1856 State, or take power saving steps in response to CPU Idle calls."
1857 This driver will make CPU Idle calls when Linux is idle (unless this
1858 feature is turned off -- see "Do CPU IDLE calls", below). This
1859 should always save battery power, but more complicated APM features
1860 will be dependent on your BIOS implementation. You may need to turn
1861 this option off if your computer hangs at boot time when using APM
1862 support, or if it beeps continuously instead of suspending. Turn
1863 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1864 T400CDT. This is off by default since most machines do fine without
1868 bool "Make CPU Idle calls when idle"
1870 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1871 On some machines, this can activate improved power savings, such as
1872 a slowed CPU clock rate, when the machine is idle. These idle calls
1873 are made after the idle loop has run for some length of time (e.g.,
1874 333 mS). On some machines, this will cause a hang at boot time or
1875 whenever the CPU becomes idle. (On machines with more than one CPU,
1876 this option does nothing.)
1878 config APM_DISPLAY_BLANK
1879 bool "Enable console blanking using APM"
1881 Enable console blanking using the APM. Some laptops can use this to
1882 turn off the LCD backlight when the screen blanker of the Linux
1883 virtual console blanks the screen. Note that this is only used by
1884 the virtual console screen blanker, and won't turn off the backlight
1885 when using the X Window system. This also doesn't have anything to
1886 do with your VESA-compliant power-saving monitor. Further, this
1887 option doesn't work for all laptops -- it might not turn off your
1888 backlight at all, or it might print a lot of errors to the console,
1889 especially if you are using gpm.
1891 config APM_ALLOW_INTS
1892 bool "Allow interrupts during APM BIOS calls"
1894 Normally we disable external interrupts while we are making calls to
1895 the APM BIOS as a measure to lessen the effects of a badly behaving
1896 BIOS implementation. The BIOS should reenable interrupts if it
1897 needs to. Unfortunately, some BIOSes do not -- especially those in
1898 many of the newer IBM Thinkpads. If you experience hangs when you
1899 suspend, try setting this to Y. Otherwise, say N.
1903 source "drivers/cpufreq/Kconfig"
1905 source "drivers/cpuidle/Kconfig"
1907 source "drivers/idle/Kconfig"
1912 menu "Bus options (PCI etc.)"
1917 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1919 Find out whether you have a PCI motherboard. PCI is the name of a
1920 bus system, i.e. the way the CPU talks to the other stuff inside
1921 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1922 VESA. If you have PCI, say Y, otherwise N.
1925 prompt "PCI access mode"
1926 depends on X86_32 && PCI
1929 On PCI systems, the BIOS can be used to detect the PCI devices and
1930 determine their configuration. However, some old PCI motherboards
1931 have BIOS bugs and may crash if this is done. Also, some embedded
1932 PCI-based systems don't have any BIOS at all. Linux can also try to
1933 detect the PCI hardware directly without using the BIOS.
1935 With this option, you can specify how Linux should detect the
1936 PCI devices. If you choose "BIOS", the BIOS will be used,
1937 if you choose "Direct", the BIOS won't be used, and if you
1938 choose "MMConfig", then PCI Express MMCONFIG will be used.
1939 If you choose "Any", the kernel will try MMCONFIG, then the
1940 direct access method and falls back to the BIOS if that doesn't
1941 work. If unsure, go with the default, which is "Any".
1946 config PCI_GOMMCONFIG
1963 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1965 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1968 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1972 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1976 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1980 depends on PCI && XEN
1988 bool "Support mmconfig PCI config space access"
1989 depends on X86_64 && PCI && ACPI
1991 config PCI_CNB20LE_QUIRK
1992 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1994 depends on PCI && EXPERIMENTAL
1996 Read the PCI windows out of the CNB20LE host bridge. This allows
1997 PCI hotplug to work on systems with the CNB20LE chipset which do
2000 There's no public spec for this chipset, and this functionality
2001 is known to be incomplete.
2003 You should say N unless you know you need this.
2005 source "drivers/pci/pcie/Kconfig"
2007 source "drivers/pci/Kconfig"
2009 # x86_64 have no ISA slots, but can have ISA-style DMA.
2011 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2014 Enables ISA-style DMA support for devices requiring such controllers.
2022 Find out whether you have ISA slots on your motherboard. ISA is the
2023 name of a bus system, i.e. the way the CPU talks to the other stuff
2024 inside your box. Other bus systems are PCI, EISA, MicroChannel
2025 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2026 newer boards don't support it. If you have ISA, say Y, otherwise N.
2032 The Extended Industry Standard Architecture (EISA) bus was
2033 developed as an open alternative to the IBM MicroChannel bus.
2035 The EISA bus provided some of the features of the IBM MicroChannel
2036 bus while maintaining backward compatibility with cards made for
2037 the older ISA bus. The EISA bus saw limited use between 1988 and
2038 1995 when it was made obsolete by the PCI bus.
2040 Say Y here if you are building a kernel for an EISA-based machine.
2044 source "drivers/eisa/Kconfig"
2049 MicroChannel Architecture is found in some IBM PS/2 machines and
2050 laptops. It is a bus system similar to PCI or ISA. See
2051 <file:Documentation/mca.txt> (and especially the web page given
2052 there) before attempting to build an MCA bus kernel.
2054 source "drivers/mca/Kconfig"
2057 tristate "NatSemi SCx200 support"
2059 This provides basic support for National Semiconductor's
2060 (now AMD's) Geode processors. The driver probes for the
2061 PCI-IDs of several on-chip devices, so its a good dependency
2062 for other scx200_* drivers.
2064 If compiled as a module, the driver is named scx200.
2066 config SCx200HR_TIMER
2067 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2071 This driver provides a clocksource built upon the on-chip
2072 27MHz high-resolution timer. Its also a workaround for
2073 NSC Geode SC-1100's buggy TSC, which loses time when the
2074 processor goes idle (as is done by the scheduler). The
2075 other workaround is idle=poll boot option.
2078 bool "One Laptop Per Child support"
2084 Add support for detecting the unique features of the OLPC
2088 bool "OLPC XO-1 Power Management"
2089 depends on OLPC && MFD_CS5535 && PM_SLEEP
2092 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2095 bool "OLPC XO-1 Real Time Clock"
2096 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2098 Add support for the XO-1 real time clock, which can be used as a
2099 programmable wakeup source.
2102 bool "OLPC XO-1 SCI extras"
2103 depends on OLPC && OLPC_XO1_PM
2108 Add support for SCI-based features of the OLPC XO-1 laptop:
2109 - EC-driven system wakeups
2113 - AC adapter status updates
2114 - Battery status updates
2116 config OLPC_XO15_SCI
2117 bool "OLPC XO-1.5 SCI extras"
2118 depends on OLPC && ACPI
2121 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2122 - EC-driven system wakeups
2123 - AC adapter status updates
2124 - Battery status updates
2127 bool "PCEngines ALIX System Support (LED setup)"
2130 This option enables system support for the PCEngines ALIX.
2131 At present this just sets up LEDs for GPIO control on
2132 ALIX2/3/6 boards. However, other system specific setup should
2135 Note: You must still enable the drivers for GPIO and LED support
2136 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2138 Note: You have to set alix.force=1 for boards with Award BIOS.
2144 depends on CPU_SUP_AMD && PCI
2146 source "drivers/pcmcia/Kconfig"
2148 source "drivers/pci/hotplug/Kconfig"
2151 bool "RapidIO support"
2155 If you say Y here, the kernel will include drivers and
2156 infrastructure code to support RapidIO interconnect devices.
2158 source "drivers/rapidio/Kconfig"
2163 menu "Executable file formats / Emulations"
2165 source "fs/Kconfig.binfmt"
2167 config IA32_EMULATION
2168 bool "IA32 Emulation"
2170 select COMPAT_BINFMT_ELF
2172 Include code to run 32-bit programs under a 64-bit kernel. You should
2173 likely turn this on, unless you're 100% sure that you don't have any
2174 32-bit programs left.
2177 tristate "IA32 a.out support"
2178 depends on IA32_EMULATION
2180 Support old a.out binaries in the 32bit emulation.
2184 depends on IA32_EMULATION
2186 config COMPAT_FOR_U64_ALIGNMENT
2190 config SYSVIPC_COMPAT
2192 depends on COMPAT && SYSVIPC
2196 depends on COMPAT && KEYS
2202 config HAVE_ATOMIC_IOMAP
2206 config HAVE_TEXT_POKE_SMP
2208 select STOP_MACHINE if SMP
2210 source "net/Kconfig"
2212 source "drivers/Kconfig"
2214 source "drivers/firmware/Kconfig"
2218 source "arch/x86/Kconfig.debug"
2220 source "security/Kconfig"
2222 source "crypto/Kconfig"
2224 source "arch/x86/kvm/Kconfig"
2226 source "lib/Kconfig"