3 bool "64-bit kernel" if ARCH = "x86"
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
18 select X86_DEV_DMA_OPS
23 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
24 select HAVE_AOUT if X86_32
25 select HAVE_UNSTABLE_SCHED_CLOCK
26 select ARCH_SUPPORTS_NUMA_BALANCING
27 select ARCH_WANTS_PROT_NUMA_PROT_NONE
30 select HAVE_PCSPKR_PLATFORM
31 select HAVE_PERF_EVENTS
32 select HAVE_IOREMAP_PROT
35 select HAVE_MEMBLOCK_NODE_MAP
36 select ARCH_DISCARD_MEMBLOCK
37 select ARCH_WANT_OPTIONAL_GPIOLIB
38 select ARCH_WANT_FRAME_POINTERS
40 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
41 select HAVE_KRETPROBES
43 select HAVE_KPROBES_ON_FTRACE
44 select HAVE_FTRACE_MCOUNT_RECORD
45 select HAVE_FENTRY if X86_64
46 select HAVE_C_RECORDMCOUNT
47 select HAVE_DYNAMIC_FTRACE
48 select HAVE_DYNAMIC_FTRACE_WITH_REGS
49 select HAVE_FUNCTION_TRACER
50 select HAVE_FUNCTION_GRAPH_TRACER
51 select HAVE_FUNCTION_GRAPH_FP_TEST
52 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
53 select HAVE_SYSCALL_TRACEPOINTS
54 select SYSCTL_EXCEPTION_TRACE
57 select HAVE_ARCH_TRACEHOOK
58 select HAVE_GENERIC_DMA_COHERENT if X86_32
59 select HAVE_EFFICIENT_UNALIGNED_ACCESS
60 select USER_STACKTRACE_SUPPORT
61 select HAVE_REGS_AND_STACK_ACCESS_API
62 select HAVE_DMA_API_DEBUG
63 select HAVE_KERNEL_GZIP
64 select HAVE_KERNEL_BZIP2
65 select HAVE_KERNEL_LZMA
67 select HAVE_KERNEL_LZO
68 select HAVE_HW_BREAKPOINT
69 select HAVE_MIXED_BREAKPOINTS_REGS
71 select HAVE_PERF_EVENTS_NMI
73 select HAVE_PERF_USER_STACK_DUMP
74 select HAVE_DEBUG_KMEMLEAK
76 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
77 select HAVE_CMPXCHG_LOCAL
78 select HAVE_CMPXCHG_DOUBLE
79 select HAVE_ARCH_KMEMCHECK
80 select HAVE_USER_RETURN_NOTIFIER
81 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
82 select HAVE_ARCH_JUMP_LABEL
83 select HAVE_TEXT_POKE_SMP
84 select HAVE_GENERIC_HARDIRQS
85 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
87 select GENERIC_FIND_FIRST_BIT
88 select GENERIC_IRQ_PROBE
89 select GENERIC_PENDING_IRQ if SMP
90 select GENERIC_IRQ_SHOW
91 select GENERIC_CLOCKEVENTS_MIN_ADJUST
92 select IRQ_FORCED_THREADING
93 select USE_GENERIC_SMP_HELPERS if SMP
94 select HAVE_BPF_JIT if X86_64
95 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
97 select ARCH_HAVE_NMI_SAFE_CMPXCHG
99 select DCACHE_WORD_ACCESS
100 select GENERIC_SMP_IDLE_THREAD
101 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
102 select HAVE_ARCH_SECCOMP_FILTER
103 select BUILDTIME_EXTABLE_SORT
104 select GENERIC_CMOS_UPDATE
105 select HAVE_ARCH_SOFT_DIRTY
106 select CLOCKSOURCE_WATCHDOG
107 select GENERIC_CLOCKEVENTS
108 select ARCH_CLOCKSOURCE_DATA if X86_64
109 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
110 select GENERIC_TIME_VSYSCALL if X86_64
111 select KTIME_SCALAR if X86_32
112 select GENERIC_STRNCPY_FROM_USER
113 select GENERIC_STRNLEN_USER
114 select HAVE_CONTEXT_TRACKING if X86_64
115 select HAVE_IRQ_TIME_ACCOUNTING
117 select MODULES_USE_ELF_REL if X86_32
118 select MODULES_USE_ELF_RELA if X86_64
119 select CLONE_BACKWARDS if X86_32
120 select ARCH_USE_BUILTIN_BSWAP
121 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
122 select OLD_SIGACTION if X86_32
123 select COMPAT_OLD_SIGACTION if IA32_EMULATION
126 config INSTRUCTION_DECODER
128 depends on KPROBES || PERF_EVENTS || UPROBES
132 default "elf32-i386" if X86_32
133 default "elf64-x86-64" if X86_64
135 config ARCH_DEFCONFIG
137 default "arch/x86/configs/i386_defconfig" if X86_32
138 default "arch/x86/configs/x86_64_defconfig" if X86_64
140 config LOCKDEP_SUPPORT
143 config STACKTRACE_SUPPORT
146 config HAVE_LATENCYTOP_SUPPORT
155 config NEED_DMA_MAP_STATE
157 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
159 config NEED_SG_DMA_LENGTH
162 config GENERIC_ISA_DMA
164 depends on ISA_DMA_API
169 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
171 config GENERIC_BUG_RELATIVE_POINTERS
174 config GENERIC_HWEIGHT
177 config ARCH_MAY_HAVE_PC_FDC
179 depends on ISA_DMA_API
181 config RWSEM_XCHGADD_ALGORITHM
184 config GENERIC_CALIBRATE_DELAY
187 config ARCH_HAS_CPU_RELAX
190 config ARCH_HAS_CACHE_LINE_SIZE
193 config ARCH_HAS_CPU_AUTOPROBE
196 config HAVE_SETUP_PER_CPU_AREA
199 config NEED_PER_CPU_EMBED_FIRST_CHUNK
202 config NEED_PER_CPU_PAGE_FIRST_CHUNK
205 config ARCH_HIBERNATION_POSSIBLE
208 config ARCH_SUSPEND_POSSIBLE
211 config ARCH_WANT_HUGE_PMD_SHARE
214 config ARCH_WANT_GENERAL_HUGETLB
225 config ARCH_SUPPORTS_OPTIMIZED_INLINING
228 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
231 config HAVE_INTEL_TXT
233 depends on INTEL_IOMMU && ACPI
237 depends on X86_32 && SMP
241 depends on X86_64 && SMP
247 config X86_32_LAZY_GS
249 depends on X86_32 && !CC_STACKPROTECTOR
251 config ARCH_HWEIGHT_CFLAGS
253 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
254 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
256 config ARCH_CPU_PROBE_RELEASE
258 depends on HOTPLUG_CPU
260 config ARCH_SUPPORTS_UPROBES
263 source "init/Kconfig"
264 source "kernel/Kconfig.freezer"
266 menu "Processor type and features"
269 bool "DMA memory allocation support" if EXPERT
272 DMA memory allocation support allows devices with less than 32-bit
273 addressing to allocate within the first 16MB of address space.
274 Disable if no such devices will be used.
279 bool "Symmetric multi-processing support"
281 This enables support for systems with more than one CPU. If you have
282 a system with only one CPU, like most personal computers, say N. If
283 you have a system with more than one CPU, say Y.
285 If you say N here, the kernel will run on single and multiprocessor
286 machines, but will use only one CPU of a multiprocessor machine. If
287 you say Y here, the kernel will run on many, but not all,
288 singleprocessor machines. On a singleprocessor machine, the kernel
289 will run faster if you say N here.
291 Note that if you say Y here and choose architecture "586" or
292 "Pentium" under "Processor family", the kernel will not work on 486
293 architectures. Similarly, multiprocessor kernels for the "PPro"
294 architecture may not work on all Pentium based boards.
296 People using multiprocessor machines who say Y here should also say
297 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
298 Management" code will be disabled if you say Y here.
300 See also <file:Documentation/x86/i386/IO-APIC.txt>,
301 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
302 <http://www.tldp.org/docs.html#howto>.
304 If you don't know what to do here, say N.
307 bool "Support x2apic"
308 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
310 This enables x2apic support on CPUs that have this feature.
312 This allows 32-bit apic IDs (so it can support very large systems),
313 and accesses the local apic via MSRs not via mmio.
315 If you don't know what to do here, say N.
318 bool "Enable MPS table" if ACPI || SFI
320 depends on X86_LOCAL_APIC
322 For old smp systems that do not have proper acpi support. Newer systems
323 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
326 bool "Support for big SMP systems with more than 8 CPUs"
327 depends on X86_32 && SMP
329 This option is needed for the systems that have more than 8 CPUs
333 depends on X86_GOLDFISH
336 config X86_EXTENDED_PLATFORM
337 bool "Support for extended (non-PC) x86 platforms"
340 If you disable this option then the kernel will only support
341 standard PC platforms. (which covers the vast majority of
344 If you enable this option then you'll be able to select support
345 for the following (non-PC) 32 bit x86 platforms:
346 Goldfish (Android emulator)
350 SGI 320/540 (Visual Workstation)
351 STA2X11-based (e.g. Northville)
352 Summit/EXA (IBM x440)
353 Unisys ES7000 IA32 series
354 Moorestown MID devices
356 If you have one of these systems, or if you want to build a
357 generic distribution kernel, say Y here - otherwise say N.
361 config X86_EXTENDED_PLATFORM
362 bool "Support for extended (non-PC) x86 platforms"
365 If you disable this option then the kernel will only support
366 standard PC platforms. (which covers the vast majority of
369 If you enable this option then you'll be able to select support
370 for the following (non-PC) 64 bit x86 platforms:
375 If you have one of these systems, or if you want to build a
376 generic distribution kernel, say Y here - otherwise say N.
378 # This is an alphabetically sorted list of 64 bit extended platforms
379 # Please maintain the alphabetic order if and when there are additions
381 bool "Numascale NumaChip"
383 depends on X86_EXTENDED_PLATFORM
386 depends on X86_X2APIC
387 depends on PCI_MMCONFIG
389 Adds support for Numascale NumaChip large-SMP systems. Needed to
390 enable more than ~168 cores.
391 If you don't have one of these, you should say N here.
395 select HYPERVISOR_GUEST
397 depends on X86_64 && PCI
398 depends on X86_EXTENDED_PLATFORM
401 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
402 supposed to run on these EM64T-based machines. Only choose this option
403 if you have one of these machines.
406 bool "SGI Ultraviolet"
408 depends on X86_EXTENDED_PLATFORM
410 depends on X86_X2APIC
412 This option is needed in order to support SGI Ultraviolet systems.
413 If you don't have one of these, you should say N here.
415 # Following is an alphabetically sorted list of 32 bit extended platforms
416 # Please maintain the alphabetic order if and when there are additions
419 bool "Goldfish (Virtual Platform)"
421 depends on X86_EXTENDED_PLATFORM
423 Enable support for the Goldfish virtual platform used primarily
424 for Android development. Unless you are building for the Android
425 Goldfish emulator say N here.
428 bool "CE4100 TV platform"
430 depends on PCI_GODIRECT
432 depends on X86_EXTENDED_PLATFORM
433 select X86_REBOOTFIXUPS
435 select OF_EARLY_FLATTREE
438 Select for the Intel CE media processor (CE4100) SOC.
439 This option compiles in support for the CE4100 SOC for settop
440 boxes and media devices.
442 config X86_WANT_INTEL_MID
443 bool "Intel MID platform support"
445 depends on X86_EXTENDED_PLATFORM
447 Select to build a kernel capable of supporting Intel MID platform
448 systems which do not have the PCI legacy interfaces (Moorestown,
449 Medfield). If you are building for a PC class system say N here.
451 if X86_WANT_INTEL_MID
457 bool "Medfield MID platform"
460 depends on X86_IO_APIC
468 select X86_PLATFORM_DEVICES
469 select MFD_INTEL_MSIC
471 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
472 Internet Device(MID) platform.
473 Unlike standard x86 PCs, Medfield does not have many legacy devices
474 nor standard legacy replacement devices/features. e.g. Medfield does
475 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
479 config X86_INTEL_LPSS
480 bool "Intel Low Power Subsystem Support"
484 Select to build support for Intel Low Power Subsystem such as
485 found on Intel Lynxpoint PCH. Selecting this option enables
486 things like clock tree (common clock framework) which are needed
487 by the LPSS peripheral drivers.
490 bool "RDC R-321x SoC"
492 depends on X86_EXTENDED_PLATFORM
494 select X86_REBOOTFIXUPS
496 This option is needed for RDC R-321x system-on-chip, also known
498 If you don't have one of these chips, you should say N here.
500 config X86_32_NON_STANDARD
501 bool "Support non-standard 32-bit SMP architectures"
502 depends on X86_32 && SMP
503 depends on X86_EXTENDED_PLATFORM
505 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
506 STA2X11, default subarchitectures. It is intended for a generic
507 binary kernel. If you select them all, kernel will probe it
508 one by one and will fallback to default.
510 # Alphabetically sorted list of Non standard 32 bit platforms
513 bool "NUMAQ (IBM/Sequent)"
514 depends on X86_32_NON_STANDARD
519 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
520 NUMA multiquad box. This changes the way that processors are
521 bootstrapped, and uses Clustered Logical APIC addressing mode instead
522 of Flat Logical. You will need a new lynxer.elf file to flash your
523 firmware with - send email to <Martin.Bligh@us.ibm.com>.
525 config X86_SUPPORTS_MEMORY_FAILURE
527 # MCE code calls memory_failure():
529 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
530 depends on !X86_NUMAQ
531 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
532 depends on X86_64 || !SPARSEMEM
533 select ARCH_SUPPORTS_MEMORY_FAILURE
536 bool "SGI 320/540 (Visual Workstation)"
537 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
538 depends on X86_32_NON_STANDARD
540 The SGI Visual Workstation series is an IA32-based workstation
541 based on SGI systems chips with some legacy PC hardware attached.
543 Say Y here to create a kernel to run on the SGI 320 or 540.
545 A kernel compiled for the Visual Workstation will run on general
546 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
549 bool "STA2X11 Companion Chip Support"
550 depends on X86_32_NON_STANDARD && PCI
551 select X86_DEV_DMA_OPS
555 select ARCH_REQUIRE_GPIOLIB
558 This adds support for boards based on the STA2X11 IO-Hub,
559 a.k.a. "ConneXt". The chip is used in place of the standard
560 PC chipset, so all "standard" peripherals are missing. If this
561 option is selected the kernel will still be able to boot on
562 standard PC machines.
565 bool "Summit/EXA (IBM x440)"
566 depends on X86_32_NON_STANDARD
568 This option is needed for IBM systems that use the Summit/EXA chipset.
569 In particular, it is needed for the x440.
572 bool "Unisys ES7000 IA32 series"
573 depends on X86_32_NON_STANDARD && X86_BIGSMP
575 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
576 supposed to run on an IA32-based Unisys ES7000 system.
579 tristate "Eurobraille/Iris poweroff module"
582 The Iris machines from EuroBraille do not have APM or ACPI support
583 to shut themselves down properly. A special I/O sequence is
584 needed to do so, which is what this module does at
587 This is only for Iris machines from EuroBraille.
591 config SCHED_OMIT_FRAME_POINTER
593 prompt "Single-depth WCHAN output"
596 Calculate simpler /proc/<PID>/wchan values. If this option
597 is disabled then wchan values will recurse back to the
598 caller function. This provides more accurate wchan values,
599 at the expense of slightly more scheduling overhead.
601 If in doubt, say "Y".
603 menuconfig HYPERVISOR_GUEST
604 bool "Linux guest support"
606 Say Y here to enable options for running Linux under various hyper-
607 visors. This option enables basic hypervisor detection and platform
610 If you say N, all options in this submenu will be skipped and
611 disabled, and Linux guest support won't be built in.
616 bool "Enable paravirtualization code"
618 This changes the kernel so it can modify itself when it is run
619 under a hypervisor, potentially improving performance significantly
620 over full virtualization. However, when run without a hypervisor
621 the kernel is theoretically slower and slightly larger.
623 config PARAVIRT_DEBUG
624 bool "paravirt-ops debugging"
625 depends on PARAVIRT && DEBUG_KERNEL
627 Enable to debug paravirt_ops internals. Specifically, BUG if
628 a paravirt_op is missing when it is called.
630 config PARAVIRT_SPINLOCKS
631 bool "Paravirtualization layer for spinlocks"
632 depends on PARAVIRT && SMP
634 Paravirtualized spinlocks allow a pvops backend to replace the
635 spinlock implementation with something virtualization-friendly
636 (for example, block the virtual CPU rather than spinning).
638 Unfortunately the downside is an up to 5% performance hit on
639 native kernels, with various workloads.
641 If you are unsure how to answer this question, answer N.
643 source "arch/x86/xen/Kconfig"
646 bool "KVM Guest support (including kvmclock)"
648 select PARAVIRT_CLOCK
651 This option enables various optimizations for running under the KVM
652 hypervisor. It includes a paravirtualized clock, so that instead
653 of relying on a PIT (or probably other) emulation by the
654 underlying device model, the host provides the guest with
655 timing infrastructure such as time of day, and system time
657 source "arch/x86/lguest/Kconfig"
659 config PARAVIRT_TIME_ACCOUNTING
660 bool "Paravirtual steal time accounting"
664 Select this option to enable fine granularity task steal time
665 accounting. Time spent executing other tasks in parallel with
666 the current vCPU is discounted from the vCPU power. To account for
667 that, there can be a small performance impact.
669 If in doubt, say N here.
671 config PARAVIRT_CLOCK
674 endif #HYPERVISOR_GUEST
682 This option adds a kernel parameter 'memtest', which allows memtest
684 memtest=0, mean disabled; -- default
685 memtest=1, mean do 1 test pattern;
687 memtest=4, mean do 4 test patterns.
688 If you are unsure how to answer this question, answer N.
690 config X86_SUMMIT_NUMA
692 depends on X86_32 && NUMA && X86_32_NON_STANDARD
694 config X86_CYCLONE_TIMER
696 depends on X86_SUMMIT
698 source "arch/x86/Kconfig.cpu"
702 prompt "HPET Timer Support" if X86_32
704 Use the IA-PC HPET (High Precision Event Timer) to manage
705 time in preference to the PIT and RTC, if a HPET is
707 HPET is the next generation timer replacing legacy 8254s.
708 The HPET provides a stable time base on SMP
709 systems, unlike the TSC, but it is more expensive to access,
710 as it is off-chip. You can find the HPET spec at
711 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
713 You can safely choose Y here. However, HPET will only be
714 activated if the platform and the BIOS support this feature.
715 Otherwise the 8254 will be used for timing services.
717 Choose N to continue using the legacy 8254 timer.
719 config HPET_EMULATE_RTC
721 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
724 def_bool y if X86_INTEL_MID
725 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
727 depends on X86_INTEL_MID && SFI
729 APB timer is the replacement for 8254, HPET on X86 MID platforms.
730 The APBT provides a stable time base on SMP
731 systems, unlike the TSC, but it is more expensive to access,
732 as it is off-chip. APB timers are always running regardless of CPU
733 C states, they are used as per CPU clockevent device when possible.
735 # Mark as expert because too many people got it wrong.
736 # The code disables itself when not needed.
739 bool "Enable DMI scanning" if EXPERT
741 Enabled scanning of DMI to identify machine quirks. Say Y
742 here unless you have verified that your setup is not
743 affected by entries in the DMI blacklist. Required by PNP
747 bool "GART IOMMU support" if EXPERT
750 depends on X86_64 && PCI && AMD_NB
752 Support for full DMA access of devices with 32bit memory access only
753 on systems with more than 3GB. This is usually needed for USB,
754 sound, many IDE/SATA chipsets and some other devices.
755 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
756 based hardware IOMMU and a software bounce buffer based IOMMU used
757 on Intel systems and as fallback.
758 The code is only active when needed (enough memory and limited
759 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
763 bool "IBM Calgary IOMMU support"
765 depends on X86_64 && PCI
767 Support for hardware IOMMUs in IBM's xSeries x366 and x460
768 systems. Needed to run systems with more than 3GB of memory
769 properly with 32-bit PCI devices that do not support DAC
770 (Double Address Cycle). Calgary also supports bus level
771 isolation, where all DMAs pass through the IOMMU. This
772 prevents them from going anywhere except their intended
773 destination. This catches hard-to-find kernel bugs and
774 mis-behaving drivers and devices that do not use the DMA-API
775 properly to set up their DMA buffers. The IOMMU can be
776 turned off at boot time with the iommu=off parameter.
777 Normally the kernel will make the right choice by itself.
780 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
782 prompt "Should Calgary be enabled by default?"
783 depends on CALGARY_IOMMU
785 Should Calgary be enabled by default? if you choose 'y', Calgary
786 will be used (if it exists). If you choose 'n', Calgary will not be
787 used even if it exists. If you choose 'n' and would like to use
788 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
791 # need this always selected by IOMMU for the VIA workaround
795 Support for software bounce buffers used on x86-64 systems
796 which don't have a hardware IOMMU. Using this PCI devices
797 which can only access 32-bits of memory can be used on systems
798 with more than 3 GB of memory.
803 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
806 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
807 depends on X86_64 && SMP && DEBUG_KERNEL
808 select CPUMASK_OFFSTACK
810 Enable maximum number of CPUS and NUMA Nodes for this architecture.
814 int "Maximum number of CPUs" if SMP && !MAXSMP
815 range 2 8 if SMP && X86_32 && !X86_BIGSMP
816 range 2 512 if SMP && !MAXSMP
818 default "4096" if MAXSMP
819 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
822 This allows you to specify the maximum number of CPUs which this
823 kernel will support. The maximum supported value is 512 and the
824 minimum value which makes sense is 2.
826 This is purely to save memory - each supported CPU adds
827 approximately eight kilobytes to the kernel image.
830 bool "SMT (Hyperthreading) scheduler support"
833 SMT scheduler support improves the CPU scheduler's decision making
834 when dealing with Intel Pentium 4 chips with HyperThreading at a
835 cost of slightly increased overhead in some places. If unsure say
840 prompt "Multi-core scheduler support"
843 Multi-core scheduler support improves the CPU scheduler's decision
844 making when dealing with multi-core CPU chips at a cost of slightly
845 increased overhead in some places. If unsure say N here.
847 source "kernel/Kconfig.preempt"
850 bool "Local APIC support on uniprocessors"
851 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
853 A local APIC (Advanced Programmable Interrupt Controller) is an
854 integrated interrupt controller in the CPU. If you have a single-CPU
855 system which has a processor with a local APIC, you can say Y here to
856 enable and use it. If you say Y here even though your machine doesn't
857 have a local APIC, then the kernel will still run with no slowdown at
858 all. The local APIC supports CPU-generated self-interrupts (timer,
859 performance counters), and the NMI watchdog which detects hard
863 bool "IO-APIC support on uniprocessors"
864 depends on X86_UP_APIC
866 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
867 SMP-capable replacement for PC-style interrupt controllers. Most
868 SMP systems and many recent uniprocessor systems have one.
870 If you have a single-CPU system with an IO-APIC, you can say Y here
871 to use it. If you say Y here even though your machine doesn't have
872 an IO-APIC, then the kernel will still run with no slowdown at all.
874 config X86_LOCAL_APIC
876 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
880 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
882 config X86_VISWS_APIC
884 depends on X86_32 && X86_VISWS
886 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
887 bool "Reroute for broken boot IRQs"
888 depends on X86_IO_APIC
890 This option enables a workaround that fixes a source of
891 spurious interrupts. This is recommended when threaded
892 interrupt handling is used on systems where the generation of
893 superfluous "boot interrupts" cannot be disabled.
895 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
896 entry in the chipset's IO-APIC is masked (as, e.g. the RT
897 kernel does during interrupt handling). On chipsets where this
898 boot IRQ generation cannot be disabled, this workaround keeps
899 the original IRQ line masked so that only the equivalent "boot
900 IRQ" is delivered to the CPUs. The workaround also tells the
901 kernel to set up the IRQ handler on the boot IRQ line. In this
902 way only one interrupt is delivered to the kernel. Otherwise
903 the spurious second interrupt may cause the kernel to bring
904 down (vital) interrupt lines.
906 Only affects "broken" chipsets. Interrupt sharing may be
907 increased on these systems.
910 bool "Machine Check / overheating reporting"
913 Machine Check support allows the processor to notify the
914 kernel if it detects a problem (e.g. overheating, data corruption).
915 The action the kernel takes depends on the severity of the problem,
916 ranging from warning messages to halting the machine.
920 prompt "Intel MCE features"
921 depends on X86_MCE && X86_LOCAL_APIC
923 Additional support for intel specific MCE features such as
928 prompt "AMD MCE features"
929 depends on X86_MCE && X86_LOCAL_APIC
931 Additional support for AMD specific MCE features such as
932 the DRAM Error Threshold.
934 config X86_ANCIENT_MCE
935 bool "Support for old Pentium 5 / WinChip machine checks"
936 depends on X86_32 && X86_MCE
938 Include support for machine check handling on old Pentium 5 or WinChip
939 systems. These typically need to be enabled explicitely on the command
942 config X86_MCE_THRESHOLD
943 depends on X86_MCE_AMD || X86_MCE_INTEL
946 config X86_MCE_INJECT
948 tristate "Machine check injector support"
950 Provide support for injecting machine checks for testing purposes.
951 If you don't know what a machine check is and you don't do kernel
952 QA it is safe to say n.
954 config X86_THERMAL_VECTOR
956 depends on X86_MCE_INTEL
959 bool "Enable VM86 support" if EXPERT
963 This option is required by programs like DOSEMU to run 16-bit legacy
964 code on X86 processors. It also may be needed by software like
965 XFree86 to initialize some video cards via BIOS. Disabling this
966 option saves about 6k.
969 tristate "Toshiba Laptop support"
972 This adds a driver to safely access the System Management Mode of
973 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
974 not work on models with a Phoenix BIOS. The System Management Mode
975 is used to set the BIOS and power saving options on Toshiba portables.
977 For information on utilities to make use of this driver see the
978 Toshiba Linux utilities web site at:
979 <http://www.buzzard.org.uk/toshiba/>.
981 Say Y if you intend to run this kernel on a Toshiba portable.
985 tristate "Dell laptop support"
988 This adds a driver to safely access the System Management Mode
989 of the CPU on the Dell Inspiron 8000. The System Management Mode
990 is used to read cpu temperature and cooling fan status and to
991 control the fans on the I8K portables.
993 This driver has been tested only on the Inspiron 8000 but it may
994 also work with other Dell laptops. You can force loading on other
995 models by passing the parameter `force=1' to the module. Use at
998 For information on utilities to make use of this driver see the
999 I8K Linux utilities web site at:
1000 <http://people.debian.org/~dz/i8k/>
1002 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1005 config X86_REBOOTFIXUPS
1006 bool "Enable X86 board specific fixups for reboot"
1009 This enables chipset and/or board specific fixups to be done
1010 in order to get reboot to work correctly. This is only needed on
1011 some combinations of hardware and BIOS. The symptom, for which
1012 this config is intended, is when reboot ends with a stalled/hung
1015 Currently, the only fixup is for the Geode machines using
1016 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1018 Say Y if you want to enable the fixup. Currently, it's safe to
1019 enable this option even if you don't need it.
1023 tristate "CPU microcode loading support"
1027 If you say Y here, you will be able to update the microcode on
1028 certain Intel and AMD processors. The Intel support is for the
1029 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1030 Xeon etc. The AMD support is for families 0x10 and later. You will
1031 obviously need the actual microcode binary data itself which is not
1032 shipped with the Linux kernel.
1034 This option selects the general module only, you need to select
1035 at least one vendor specific module as well.
1037 To compile this driver as a module, choose M here: the module
1038 will be called microcode.
1040 config MICROCODE_INTEL
1041 bool "Intel microcode loading support"
1042 depends on MICROCODE
1046 This options enables microcode patch loading support for Intel
1049 For latest news and information on obtaining all the required
1050 Intel ingredients for this driver, check:
1051 <http://www.urbanmyth.org/microcode/>.
1053 config MICROCODE_AMD
1054 bool "AMD microcode loading support"
1055 depends on MICROCODE
1058 If you select this option, microcode patch loading support for AMD
1059 processors will be enabled.
1061 config MICROCODE_OLD_INTERFACE
1063 depends on MICROCODE
1065 config MICROCODE_INTEL_LIB
1067 depends on MICROCODE_INTEL
1069 config MICROCODE_INTEL_EARLY
1072 config MICROCODE_AMD_EARLY
1075 config MICROCODE_EARLY
1076 bool "Early load microcode"
1077 depends on MICROCODE=y && BLK_DEV_INITRD
1078 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1079 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1082 This option provides functionality to read additional microcode data
1083 at the beginning of initrd image. The data tells kernel to load
1084 microcode to CPU's as early as possible. No functional change if no
1085 microcode data is glued to the initrd, therefore it's safe to say Y.
1088 tristate "/dev/cpu/*/msr - Model-specific register support"
1090 This device gives privileged processes access to the x86
1091 Model-Specific Registers (MSRs). It is a character device with
1092 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1093 MSR accesses are directed to a specific CPU on multi-processor
1097 tristate "/dev/cpu/*/cpuid - CPU information support"
1099 This device gives processes access to the x86 CPUID instruction to
1100 be executed on a specific processor. It is a character device
1101 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1105 prompt "High Memory Support"
1106 default HIGHMEM64G if X86_NUMAQ
1112 depends on !X86_NUMAQ
1114 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1115 However, the address space of 32-bit x86 processors is only 4
1116 Gigabytes large. That means that, if you have a large amount of
1117 physical memory, not all of it can be "permanently mapped" by the
1118 kernel. The physical memory that's not permanently mapped is called
1121 If you are compiling a kernel which will never run on a machine with
1122 more than 1 Gigabyte total physical RAM, answer "off" here (default
1123 choice and suitable for most users). This will result in a "3GB/1GB"
1124 split: 3GB are mapped so that each process sees a 3GB virtual memory
1125 space and the remaining part of the 4GB virtual memory space is used
1126 by the kernel to permanently map as much physical memory as
1129 If the machine has between 1 and 4 Gigabytes physical RAM, then
1132 If more than 4 Gigabytes is used then answer "64GB" here. This
1133 selection turns Intel PAE (Physical Address Extension) mode on.
1134 PAE implements 3-level paging on IA32 processors. PAE is fully
1135 supported by Linux, PAE mode is implemented on all recent Intel
1136 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1137 then the kernel will not boot on CPUs that don't support PAE!
1139 The actual amount of total physical memory will either be
1140 auto detected or can be forced by using a kernel command line option
1141 such as "mem=256M". (Try "man bootparam" or see the documentation of
1142 your boot loader (lilo or loadlin) about how to pass options to the
1143 kernel at boot time.)
1145 If unsure, say "off".
1149 depends on !X86_NUMAQ
1151 Select this if you have a 32-bit processor and between 1 and 4
1152 gigabytes of physical RAM.
1159 Select this if you have a 32-bit processor and more than 4
1160 gigabytes of physical RAM.
1165 prompt "Memory split" if EXPERT
1169 Select the desired split between kernel and user memory.
1171 If the address range available to the kernel is less than the
1172 physical memory installed, the remaining memory will be available
1173 as "high memory". Accessing high memory is a little more costly
1174 than low memory, as it needs to be mapped into the kernel first.
1175 Note that increasing the kernel address space limits the range
1176 available to user programs, making the address space there
1177 tighter. Selecting anything other than the default 3G/1G split
1178 will also likely make your kernel incompatible with binary-only
1181 If you are not absolutely sure what you are doing, leave this
1185 bool "3G/1G user/kernel split"
1186 config VMSPLIT_3G_OPT
1188 bool "3G/1G user/kernel split (for full 1G low memory)"
1190 bool "2G/2G user/kernel split"
1191 config VMSPLIT_2G_OPT
1193 bool "2G/2G user/kernel split (for full 2G low memory)"
1195 bool "1G/3G user/kernel split"
1200 default 0xB0000000 if VMSPLIT_3G_OPT
1201 default 0x80000000 if VMSPLIT_2G
1202 default 0x78000000 if VMSPLIT_2G_OPT
1203 default 0x40000000 if VMSPLIT_1G
1209 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1212 bool "PAE (Physical Address Extension) Support"
1213 depends on X86_32 && !HIGHMEM4G
1215 PAE is required for NX support, and furthermore enables
1216 larger swapspace support for non-overcommit purposes. It
1217 has the cost of more pagetable lookup overhead, and also
1218 consumes more pagetable space per process.
1220 config ARCH_PHYS_ADDR_T_64BIT
1222 depends on X86_64 || X86_PAE
1224 config ARCH_DMA_ADDR_T_64BIT
1226 depends on X86_64 || HIGHMEM64G
1228 config DIRECT_GBPAGES
1229 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1233 Allow the kernel linear mapping to use 1GB pages on CPUs that
1234 support it. This can improve the kernel's performance a tiny bit by
1235 reducing TLB pressure. If in doubt, say "Y".
1237 # Common NUMA Features
1239 bool "Numa Memory Allocation and Scheduler Support"
1241 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI))
1242 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1244 Enable NUMA (Non Uniform Memory Access) support.
1246 The kernel will try to allocate memory used by a CPU on the
1247 local memory controller of the CPU and add some more
1248 NUMA awareness to the kernel.
1250 For 64-bit this is recommended if the system is Intel Core i7
1251 (or later), AMD Opteron, or EM64T NUMA.
1253 For 32-bit this is only needed on (rare) 32-bit-only platforms
1254 that support NUMA topologies, such as NUMAQ / Summit, or if you
1255 boot a 32-bit kernel on a 64-bit NUMA platform.
1257 Otherwise, you should say N.
1259 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1260 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1264 prompt "Old style AMD Opteron NUMA detection"
1265 depends on X86_64 && NUMA && PCI
1267 Enable AMD NUMA node topology detection. You should say Y here if
1268 you have a multi processor AMD system. This uses an old method to
1269 read the NUMA configuration directly from the builtin Northbridge
1270 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1271 which also takes priority if both are compiled in.
1273 config X86_64_ACPI_NUMA
1275 prompt "ACPI NUMA detection"
1276 depends on X86_64 && NUMA && ACPI && PCI
1279 Enable ACPI SRAT based node topology detection.
1281 # Some NUMA nodes have memory ranges that span
1282 # other nodes. Even though a pfn is valid and
1283 # between a node's start and end pfns, it may not
1284 # reside on that node. See memmap_init_zone()
1286 config NODES_SPAN_OTHER_NODES
1288 depends on X86_64_ACPI_NUMA
1291 bool "NUMA emulation"
1294 Enable NUMA emulation. A flat machine will be split
1295 into virtual nodes when booted with "numa=fake=N", where N is the
1296 number of nodes. This is only useful for debugging.
1299 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1301 default "10" if MAXSMP
1302 default "6" if X86_64
1303 default "4" if X86_NUMAQ
1305 depends on NEED_MULTIPLE_NODES
1307 Specify the maximum number of NUMA Nodes available on the target
1308 system. Increases memory reserved to accommodate various tables.
1310 config ARCH_HAVE_MEMORY_PRESENT
1312 depends on X86_32 && DISCONTIGMEM
1314 config NEED_NODE_MEMMAP_SIZE
1316 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1318 config ARCH_FLATMEM_ENABLE
1320 depends on X86_32 && !NUMA
1322 config ARCH_DISCONTIGMEM_ENABLE
1324 depends on NUMA && X86_32
1326 config ARCH_DISCONTIGMEM_DEFAULT
1328 depends on NUMA && X86_32
1330 config ARCH_SPARSEMEM_ENABLE
1332 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1333 select SPARSEMEM_STATIC if X86_32
1334 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1336 config ARCH_SPARSEMEM_DEFAULT
1340 config ARCH_SELECT_MEMORY_MODEL
1342 depends on ARCH_SPARSEMEM_ENABLE
1344 config ARCH_MEMORY_PROBE
1346 depends on X86_64 && MEMORY_HOTPLUG
1348 config ARCH_PROC_KCORE_TEXT
1350 depends on X86_64 && PROC_KCORE
1352 config ILLEGAL_POINTER_VALUE
1355 default 0xdead000000000000 if X86_64
1360 bool "Allocate 3rd-level pagetables from highmem"
1363 The VM uses one page table entry for each page of physical memory.
1364 For systems with a lot of RAM, this can be wasteful of precious
1365 low memory. Setting this option will put user-space page table
1366 entries in high memory.
1368 config X86_CHECK_BIOS_CORRUPTION
1369 bool "Check for low memory corruption"
1371 Periodically check for memory corruption in low memory, which
1372 is suspected to be caused by BIOS. Even when enabled in the
1373 configuration, it is disabled at runtime. Enable it by
1374 setting "memory_corruption_check=1" on the kernel command
1375 line. By default it scans the low 64k of memory every 60
1376 seconds; see the memory_corruption_check_size and
1377 memory_corruption_check_period parameters in
1378 Documentation/kernel-parameters.txt to adjust this.
1380 When enabled with the default parameters, this option has
1381 almost no overhead, as it reserves a relatively small amount
1382 of memory and scans it infrequently. It both detects corruption
1383 and prevents it from affecting the running system.
1385 It is, however, intended as a diagnostic tool; if repeatable
1386 BIOS-originated corruption always affects the same memory,
1387 you can use memmap= to prevent the kernel from using that
1390 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1391 bool "Set the default setting of memory_corruption_check"
1392 depends on X86_CHECK_BIOS_CORRUPTION
1395 Set whether the default state of memory_corruption_check is
1398 config X86_RESERVE_LOW
1399 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1403 Specify the amount of low memory to reserve for the BIOS.
1405 The first page contains BIOS data structures that the kernel
1406 must not use, so that page must always be reserved.
1408 By default we reserve the first 64K of physical RAM, as a
1409 number of BIOSes are known to corrupt that memory range
1410 during events such as suspend/resume or monitor cable
1411 insertion, so it must not be used by the kernel.
1413 You can set this to 4 if you are absolutely sure that you
1414 trust the BIOS to get all its memory reservations and usages
1415 right. If you know your BIOS have problems beyond the
1416 default 64K area, you can set this to 640 to avoid using the
1417 entire low memory range.
1419 If you have doubts about the BIOS (e.g. suspend/resume does
1420 not work or there's kernel crashes after certain hardware
1421 hotplug events) then you might want to enable
1422 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1423 typical corruption patterns.
1425 Leave this to the default value of 64 if you are unsure.
1427 config MATH_EMULATION
1429 prompt "Math emulation" if X86_32
1431 Linux can emulate a math coprocessor (used for floating point
1432 operations) if you don't have one. 486DX and Pentium processors have
1433 a math coprocessor built in, 486SX and 386 do not, unless you added
1434 a 487DX or 387, respectively. (The messages during boot time can
1435 give you some hints here ["man dmesg"].) Everyone needs either a
1436 coprocessor or this emulation.
1438 If you don't have a math coprocessor, you need to say Y here; if you
1439 say Y here even though you have a coprocessor, the coprocessor will
1440 be used nevertheless. (This behavior can be changed with the kernel
1441 command line option "no387", which comes handy if your coprocessor
1442 is broken. Try "man bootparam" or see the documentation of your boot
1443 loader (lilo or loadlin) about how to pass options to the kernel at
1444 boot time.) This means that it is a good idea to say Y here if you
1445 intend to use this kernel on different machines.
1447 More information about the internals of the Linux math coprocessor
1448 emulation can be found in <file:arch/x86/math-emu/README>.
1450 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1451 kernel, it won't hurt.
1455 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1457 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1458 the Memory Type Range Registers (MTRRs) may be used to control
1459 processor access to memory ranges. This is most useful if you have
1460 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1461 allows bus write transfers to be combined into a larger transfer
1462 before bursting over the PCI/AGP bus. This can increase performance
1463 of image write operations 2.5 times or more. Saying Y here creates a
1464 /proc/mtrr file which may be used to manipulate your processor's
1465 MTRRs. Typically the X server should use this.
1467 This code has a reasonably generic interface so that similar
1468 control registers on other processors can be easily supported
1471 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1472 Registers (ARRs) which provide a similar functionality to MTRRs. For
1473 these, the ARRs are used to emulate the MTRRs.
1474 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1475 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1476 write-combining. All of these processors are supported by this code
1477 and it makes sense to say Y here if you have one of them.
1479 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1480 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1481 can lead to all sorts of problems, so it's good to say Y here.
1483 You can safely say Y even if your machine doesn't have MTRRs, you'll
1484 just add about 9 KB to your kernel.
1486 See <file:Documentation/x86/mtrr.txt> for more information.
1488 config MTRR_SANITIZER
1490 prompt "MTRR cleanup support"
1493 Convert MTRR layout from continuous to discrete, so X drivers can
1494 add writeback entries.
1496 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1497 The largest mtrr entry size for a continuous block can be set with
1502 config MTRR_SANITIZER_ENABLE_DEFAULT
1503 int "MTRR cleanup enable value (0-1)"
1506 depends on MTRR_SANITIZER
1508 Enable mtrr cleanup default value
1510 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1511 int "MTRR cleanup spare reg num (0-7)"
1514 depends on MTRR_SANITIZER
1516 mtrr cleanup spare entries default, it can be changed via
1517 mtrr_spare_reg_nr=N on the kernel command line.
1521 prompt "x86 PAT support" if EXPERT
1524 Use PAT attributes to setup page level cache control.
1526 PATs are the modern equivalents of MTRRs and are much more
1527 flexible than MTRRs.
1529 Say N here if you see bootup problems (boot crash, boot hang,
1530 spontaneous reboots) or a non-working video driver.
1534 config ARCH_USES_PG_UNCACHED
1540 prompt "x86 architectural random number generator" if EXPERT
1542 Enable the x86 architectural RDRAND instruction
1543 (Intel Bull Mountain technology) to generate random numbers.
1544 If supported, this is a high bandwidth, cryptographically
1545 secure hardware random number generator.
1549 prompt "Supervisor Mode Access Prevention" if EXPERT
1551 Supervisor Mode Access Prevention (SMAP) is a security
1552 feature in newer Intel processors. There is a small
1553 performance cost if this enabled and turned on; there is
1554 also a small increase in the kernel size if this is enabled.
1559 bool "EFI runtime service support"
1563 This enables the kernel to use EFI runtime services that are
1564 available (such as the EFI variable services).
1566 This option is only useful on systems that have EFI firmware.
1567 In addition, you should use the latest ELILO loader available
1568 at <http://elilo.sourceforge.net> in order to take advantage
1569 of EFI runtime services. However, even with this option, the
1570 resultant kernel should continue to boot on existing non-EFI
1574 bool "EFI stub support"
1577 This kernel feature allows a bzImage to be loaded directly
1578 by EFI firmware without the use of a bootloader.
1580 See Documentation/x86/efi-stub.txt for more information.
1584 prompt "Enable seccomp to safely compute untrusted bytecode"
1586 This kernel feature is useful for number crunching applications
1587 that may need to compute untrusted bytecode during their
1588 execution. By using pipes or other transports made available to
1589 the process as file descriptors supporting the read/write
1590 syscalls, it's possible to isolate those applications in
1591 their own address space using seccomp. Once seccomp is
1592 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1593 and the task is only allowed to execute a few safe syscalls
1594 defined by each seccomp mode.
1596 If unsure, say Y. Only embedded should say N here.
1598 config CC_STACKPROTECTOR
1599 bool "Enable -fstack-protector buffer overflow detection"
1601 This option turns on the -fstack-protector GCC feature. This
1602 feature puts, at the beginning of functions, a canary value on
1603 the stack just before the return address, and validates
1604 the value just before actually returning. Stack based buffer
1605 overflows (that need to overwrite this return address) now also
1606 overwrite the canary, which gets detected and the attack is then
1607 neutralized via a kernel panic.
1609 This feature requires gcc version 4.2 or above, or a distribution
1610 gcc with the feature backported. Older versions are automatically
1611 detected and for those versions, this configuration option is
1612 ignored. (and a warning is printed during bootup)
1614 source kernel/Kconfig.hz
1617 bool "kexec system call"
1619 kexec is a system call that implements the ability to shutdown your
1620 current kernel, and to start another kernel. It is like a reboot
1621 but it is independent of the system firmware. And like a reboot
1622 you can start any kernel with it, not just Linux.
1624 The name comes from the similarity to the exec system call.
1626 It is an ongoing process to be certain the hardware in a machine
1627 is properly shutdown, so do not be surprised if this code does not
1628 initially work for you. It may help to enable device hotplugging
1629 support. As of this writing the exact hardware interface is
1630 strongly in flux, so no good recommendation can be made.
1633 bool "kernel crash dumps"
1634 depends on X86_64 || (X86_32 && HIGHMEM)
1636 Generate crash dump after being started by kexec.
1637 This should be normally only set in special crash dump kernels
1638 which are loaded in the main kernel with kexec-tools into
1639 a specially reserved region and then later executed after
1640 a crash by kdump/kexec. The crash dump kernel must be compiled
1641 to a memory address not used by the main kernel or BIOS using
1642 PHYSICAL_START, or it must be built as a relocatable image
1643 (CONFIG_RELOCATABLE=y).
1644 For more details see Documentation/kdump/kdump.txt
1648 depends on KEXEC && HIBERNATION
1650 Jump between original kernel and kexeced kernel and invoke
1651 code in physical address mode via KEXEC
1653 config PHYSICAL_START
1654 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1657 This gives the physical address where the kernel is loaded.
1659 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1660 bzImage will decompress itself to above physical address and
1661 run from there. Otherwise, bzImage will run from the address where
1662 it has been loaded by the boot loader and will ignore above physical
1665 In normal kdump cases one does not have to set/change this option
1666 as now bzImage can be compiled as a completely relocatable image
1667 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1668 address. This option is mainly useful for the folks who don't want
1669 to use a bzImage for capturing the crash dump and want to use a
1670 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1671 to be specifically compiled to run from a specific memory area
1672 (normally a reserved region) and this option comes handy.
1674 So if you are using bzImage for capturing the crash dump,
1675 leave the value here unchanged to 0x1000000 and set
1676 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1677 for capturing the crash dump change this value to start of
1678 the reserved region. In other words, it can be set based on
1679 the "X" value as specified in the "crashkernel=YM@XM"
1680 command line boot parameter passed to the panic-ed
1681 kernel. Please take a look at Documentation/kdump/kdump.txt
1682 for more details about crash dumps.
1684 Usage of bzImage for capturing the crash dump is recommended as
1685 one does not have to build two kernels. Same kernel can be used
1686 as production kernel and capture kernel. Above option should have
1687 gone away after relocatable bzImage support is introduced. But it
1688 is present because there are users out there who continue to use
1689 vmlinux for dump capture. This option should go away down the
1692 Don't change this unless you know what you are doing.
1695 bool "Build a relocatable kernel"
1698 This builds a kernel image that retains relocation information
1699 so it can be loaded someplace besides the default 1MB.
1700 The relocations tend to make the kernel binary about 10% larger,
1701 but are discarded at runtime.
1703 One use is for the kexec on panic case where the recovery kernel
1704 must live at a different physical address than the primary
1707 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1708 it has been loaded at and the compile time physical address
1709 (CONFIG_PHYSICAL_START) is ignored.
1711 # Relocation on x86-32 needs some additional build support
1712 config X86_NEED_RELOCS
1714 depends on X86_32 && RELOCATABLE
1716 config PHYSICAL_ALIGN
1717 hex "Alignment value to which kernel should be aligned" if X86_32
1719 range 0x2000 0x1000000
1721 This value puts the alignment restrictions on physical address
1722 where kernel is loaded and run from. Kernel is compiled for an
1723 address which meets above alignment restriction.
1725 If bootloader loads the kernel at a non-aligned address and
1726 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1727 address aligned to above value and run from there.
1729 If bootloader loads the kernel at a non-aligned address and
1730 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1731 load address and decompress itself to the address it has been
1732 compiled for and run from there. The address for which kernel is
1733 compiled already meets above alignment restrictions. Hence the
1734 end result is that kernel runs from a physical address meeting
1735 above alignment restrictions.
1737 Don't change this unless you know what you are doing.
1740 bool "Support for hot-pluggable CPUs"
1743 Say Y here to allow turning CPUs off and on. CPUs can be
1744 controlled through /sys/devices/system/cpu.
1745 ( Note: power management support will enable this option
1746 automatically on SMP systems. )
1747 Say N if you want to disable CPU hotplug.
1749 config BOOTPARAM_HOTPLUG_CPU0
1750 bool "Set default setting of cpu0_hotpluggable"
1752 depends on HOTPLUG_CPU
1754 Set whether default state of cpu0_hotpluggable is on or off.
1756 Say Y here to enable CPU0 hotplug by default. If this switch
1757 is turned on, there is no need to give cpu0_hotplug kernel
1758 parameter and the CPU0 hotplug feature is enabled by default.
1760 Please note: there are two known CPU0 dependencies if you want
1761 to enable the CPU0 hotplug feature either by this switch or by
1762 cpu0_hotplug kernel parameter.
1764 First, resume from hibernate or suspend always starts from CPU0.
1765 So hibernate and suspend are prevented if CPU0 is offline.
1767 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1768 offline if any interrupt can not migrate out of CPU0. There may
1769 be other CPU0 dependencies.
1771 Please make sure the dependencies are under your control before
1772 you enable this feature.
1774 Say N if you don't want to enable CPU0 hotplug feature by default.
1775 You still can enable the CPU0 hotplug feature at boot by kernel
1776 parameter cpu0_hotplug.
1778 config DEBUG_HOTPLUG_CPU0
1780 prompt "Debug CPU0 hotplug"
1781 depends on HOTPLUG_CPU
1783 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1784 soon as possible and boots up userspace with CPU0 offlined. User
1785 can online CPU0 back after boot time.
1787 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1788 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1789 compilation or giving cpu0_hotplug kernel parameter at boot.
1795 prompt "Compat VDSO support"
1796 depends on X86_32 || IA32_EMULATION
1798 Map the 32-bit VDSO to the predictable old-style address too.
1800 Say N here if you are running a sufficiently recent glibc
1801 version (2.3.3 or later), to remove the high-mapped
1802 VDSO mapping and to exclusively use the randomized VDSO.
1807 bool "Built-in kernel command line"
1809 Allow for specifying boot arguments to the kernel at
1810 build time. On some systems (e.g. embedded ones), it is
1811 necessary or convenient to provide some or all of the
1812 kernel boot arguments with the kernel itself (that is,
1813 to not rely on the boot loader to provide them.)
1815 To compile command line arguments into the kernel,
1816 set this option to 'Y', then fill in the
1817 the boot arguments in CONFIG_CMDLINE.
1819 Systems with fully functional boot loaders (i.e. non-embedded)
1820 should leave this option set to 'N'.
1823 string "Built-in kernel command string"
1824 depends on CMDLINE_BOOL
1827 Enter arguments here that should be compiled into the kernel
1828 image and used at boot time. If the boot loader provides a
1829 command line at boot time, it is appended to this string to
1830 form the full kernel command line, when the system boots.
1832 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1833 change this behavior.
1835 In most cases, the command line (whether built-in or provided
1836 by the boot loader) should specify the device for the root
1839 config CMDLINE_OVERRIDE
1840 bool "Built-in command line overrides boot loader arguments"
1841 depends on CMDLINE_BOOL
1843 Set this option to 'Y' to have the kernel ignore the boot loader
1844 command line, and use ONLY the built-in command line.
1846 This is used to work around broken boot loaders. This should
1847 be set to 'N' under normal conditions.
1851 config ARCH_ENABLE_MEMORY_HOTPLUG
1853 depends on X86_64 || (X86_32 && HIGHMEM)
1855 config ARCH_ENABLE_MEMORY_HOTREMOVE
1857 depends on MEMORY_HOTPLUG
1859 config USE_PERCPU_NUMA_NODE_ID
1863 menu "Power management and ACPI options"
1865 config ARCH_HIBERNATION_HEADER
1867 depends on X86_64 && HIBERNATION
1869 source "kernel/power/Kconfig"
1871 source "drivers/acpi/Kconfig"
1873 source "drivers/sfi/Kconfig"
1880 tristate "APM (Advanced Power Management) BIOS support"
1881 depends on X86_32 && PM_SLEEP
1883 APM is a BIOS specification for saving power using several different
1884 techniques. This is mostly useful for battery powered laptops with
1885 APM compliant BIOSes. If you say Y here, the system time will be
1886 reset after a RESUME operation, the /proc/apm device will provide
1887 battery status information, and user-space programs will receive
1888 notification of APM "events" (e.g. battery status change).
1890 If you select "Y" here, you can disable actual use of the APM
1891 BIOS by passing the "apm=off" option to the kernel at boot time.
1893 Note that the APM support is almost completely disabled for
1894 machines with more than one CPU.
1896 In order to use APM, you will need supporting software. For location
1897 and more information, read <file:Documentation/power/apm-acpi.txt>
1898 and the Battery Powered Linux mini-HOWTO, available from
1899 <http://www.tldp.org/docs.html#howto>.
1901 This driver does not spin down disk drives (see the hdparm(8)
1902 manpage ("man 8 hdparm") for that), and it doesn't turn off
1903 VESA-compliant "green" monitors.
1905 This driver does not support the TI 4000M TravelMate and the ACER
1906 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1907 desktop machines also don't have compliant BIOSes, and this driver
1908 may cause those machines to panic during the boot phase.
1910 Generally, if you don't have a battery in your machine, there isn't
1911 much point in using this driver and you should say N. If you get
1912 random kernel OOPSes or reboots that don't seem to be related to
1913 anything, try disabling/enabling this option (or disabling/enabling
1916 Some other things you should try when experiencing seemingly random,
1919 1) make sure that you have enough swap space and that it is
1921 2) pass the "no-hlt" option to the kernel
1922 3) switch on floating point emulation in the kernel and pass
1923 the "no387" option to the kernel
1924 4) pass the "floppy=nodma" option to the kernel
1925 5) pass the "mem=4M" option to the kernel (thereby disabling
1926 all but the first 4 MB of RAM)
1927 6) make sure that the CPU is not over clocked.
1928 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1929 8) disable the cache from your BIOS settings
1930 9) install a fan for the video card or exchange video RAM
1931 10) install a better fan for the CPU
1932 11) exchange RAM chips
1933 12) exchange the motherboard.
1935 To compile this driver as a module, choose M here: the
1936 module will be called apm.
1940 config APM_IGNORE_USER_SUSPEND
1941 bool "Ignore USER SUSPEND"
1943 This option will ignore USER SUSPEND requests. On machines with a
1944 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1945 series notebooks, it is necessary to say Y because of a BIOS bug.
1947 config APM_DO_ENABLE
1948 bool "Enable PM at boot time"
1950 Enable APM features at boot time. From page 36 of the APM BIOS
1951 specification: "When disabled, the APM BIOS does not automatically
1952 power manage devices, enter the Standby State, enter the Suspend
1953 State, or take power saving steps in response to CPU Idle calls."
1954 This driver will make CPU Idle calls when Linux is idle (unless this
1955 feature is turned off -- see "Do CPU IDLE calls", below). This
1956 should always save battery power, but more complicated APM features
1957 will be dependent on your BIOS implementation. You may need to turn
1958 this option off if your computer hangs at boot time when using APM
1959 support, or if it beeps continuously instead of suspending. Turn
1960 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1961 T400CDT. This is off by default since most machines do fine without
1966 bool "Make CPU Idle calls when idle"
1968 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1969 On some machines, this can activate improved power savings, such as
1970 a slowed CPU clock rate, when the machine is idle. These idle calls
1971 are made after the idle loop has run for some length of time (e.g.,
1972 333 mS). On some machines, this will cause a hang at boot time or
1973 whenever the CPU becomes idle. (On machines with more than one CPU,
1974 this option does nothing.)
1976 config APM_DISPLAY_BLANK
1977 bool "Enable console blanking using APM"
1979 Enable console blanking using the APM. Some laptops can use this to
1980 turn off the LCD backlight when the screen blanker of the Linux
1981 virtual console blanks the screen. Note that this is only used by
1982 the virtual console screen blanker, and won't turn off the backlight
1983 when using the X Window system. This also doesn't have anything to
1984 do with your VESA-compliant power-saving monitor. Further, this
1985 option doesn't work for all laptops -- it might not turn off your
1986 backlight at all, or it might print a lot of errors to the console,
1987 especially if you are using gpm.
1989 config APM_ALLOW_INTS
1990 bool "Allow interrupts during APM BIOS calls"
1992 Normally we disable external interrupts while we are making calls to
1993 the APM BIOS as a measure to lessen the effects of a badly behaving
1994 BIOS implementation. The BIOS should reenable interrupts if it
1995 needs to. Unfortunately, some BIOSes do not -- especially those in
1996 many of the newer IBM Thinkpads. If you experience hangs when you
1997 suspend, try setting this to Y. Otherwise, say N.
2001 source "drivers/cpufreq/Kconfig"
2003 source "drivers/cpuidle/Kconfig"
2005 source "drivers/idle/Kconfig"
2010 menu "Bus options (PCI etc.)"
2015 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
2017 Find out whether you have a PCI motherboard. PCI is the name of a
2018 bus system, i.e. the way the CPU talks to the other stuff inside
2019 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2020 VESA. If you have PCI, say Y, otherwise N.
2023 prompt "PCI access mode"
2024 depends on X86_32 && PCI
2027 On PCI systems, the BIOS can be used to detect the PCI devices and
2028 determine their configuration. However, some old PCI motherboards
2029 have BIOS bugs and may crash if this is done. Also, some embedded
2030 PCI-based systems don't have any BIOS at all. Linux can also try to
2031 detect the PCI hardware directly without using the BIOS.
2033 With this option, you can specify how Linux should detect the
2034 PCI devices. If you choose "BIOS", the BIOS will be used,
2035 if you choose "Direct", the BIOS won't be used, and if you
2036 choose "MMConfig", then PCI Express MMCONFIG will be used.
2037 If you choose "Any", the kernel will try MMCONFIG, then the
2038 direct access method and falls back to the BIOS if that doesn't
2039 work. If unsure, go with the default, which is "Any".
2044 config PCI_GOMMCONFIG
2061 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2063 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2066 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2070 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2074 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2078 depends on PCI && XEN
2086 bool "Support mmconfig PCI config space access"
2087 depends on X86_64 && PCI && ACPI
2089 config PCI_CNB20LE_QUIRK
2090 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2093 Read the PCI windows out of the CNB20LE host bridge. This allows
2094 PCI hotplug to work on systems with the CNB20LE chipset which do
2097 There's no public spec for this chipset, and this functionality
2098 is known to be incomplete.
2100 You should say N unless you know you need this.
2102 source "drivers/pci/pcie/Kconfig"
2104 source "drivers/pci/Kconfig"
2106 # x86_64 have no ISA slots, but can have ISA-style DMA.
2108 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2111 Enables ISA-style DMA support for devices requiring such controllers.
2119 Find out whether you have ISA slots on your motherboard. ISA is the
2120 name of a bus system, i.e. the way the CPU talks to the other stuff
2121 inside your box. Other bus systems are PCI, EISA, MicroChannel
2122 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2123 newer boards don't support it. If you have ISA, say Y, otherwise N.
2129 The Extended Industry Standard Architecture (EISA) bus was
2130 developed as an open alternative to the IBM MicroChannel bus.
2132 The EISA bus provided some of the features of the IBM MicroChannel
2133 bus while maintaining backward compatibility with cards made for
2134 the older ISA bus. The EISA bus saw limited use between 1988 and
2135 1995 when it was made obsolete by the PCI bus.
2137 Say Y here if you are building a kernel for an EISA-based machine.
2141 source "drivers/eisa/Kconfig"
2144 tristate "NatSemi SCx200 support"
2146 This provides basic support for National Semiconductor's
2147 (now AMD's) Geode processors. The driver probes for the
2148 PCI-IDs of several on-chip devices, so its a good dependency
2149 for other scx200_* drivers.
2151 If compiled as a module, the driver is named scx200.
2153 config SCx200HR_TIMER
2154 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2158 This driver provides a clocksource built upon the on-chip
2159 27MHz high-resolution timer. Its also a workaround for
2160 NSC Geode SC-1100's buggy TSC, which loses time when the
2161 processor goes idle (as is done by the scheduler). The
2162 other workaround is idle=poll boot option.
2165 bool "One Laptop Per Child support"
2172 Add support for detecting the unique features of the OLPC
2176 bool "OLPC XO-1 Power Management"
2177 depends on OLPC && MFD_CS5535 && PM_SLEEP
2180 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2183 bool "OLPC XO-1 Real Time Clock"
2184 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2186 Add support for the XO-1 real time clock, which can be used as a
2187 programmable wakeup source.
2190 bool "OLPC XO-1 SCI extras"
2191 depends on OLPC && OLPC_XO1_PM
2197 Add support for SCI-based features of the OLPC XO-1 laptop:
2198 - EC-driven system wakeups
2202 - AC adapter status updates
2203 - Battery status updates
2205 config OLPC_XO15_SCI
2206 bool "OLPC XO-1.5 SCI extras"
2207 depends on OLPC && ACPI
2210 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2211 - EC-driven system wakeups
2212 - AC adapter status updates
2213 - Battery status updates
2216 bool "PCEngines ALIX System Support (LED setup)"
2219 This option enables system support for the PCEngines ALIX.
2220 At present this just sets up LEDs for GPIO control on
2221 ALIX2/3/6 boards. However, other system specific setup should
2224 Note: You must still enable the drivers for GPIO and LED support
2225 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2227 Note: You have to set alix.force=1 for boards with Award BIOS.
2230 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2233 This option enables system support for the Soekris Engineering net5501.
2236 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2240 This option enables system support for the Traverse Technologies GEOS.
2243 bool "Technologic Systems TS-5500 platform support"
2245 select CHECK_SIGNATURE
2249 This option enables system support for the Technologic Systems TS-5500.
2255 depends on CPU_SUP_AMD && PCI
2257 source "drivers/pcmcia/Kconfig"
2259 source "drivers/pci/hotplug/Kconfig"
2262 bool "RapidIO support"
2266 If you say Y here, the kernel will include drivers and
2267 infrastructure code to support RapidIO interconnect devices.
2269 source "drivers/rapidio/Kconfig"
2274 menu "Executable file formats / Emulations"
2276 source "fs/Kconfig.binfmt"
2278 config IA32_EMULATION
2279 bool "IA32 Emulation"
2282 select COMPAT_BINFMT_ELF
2285 Include code to run legacy 32-bit programs under a
2286 64-bit kernel. You should likely turn this on, unless you're
2287 100% sure that you don't have any 32-bit programs left.
2290 tristate "IA32 a.out support"
2291 depends on IA32_EMULATION
2293 Support old a.out binaries in the 32bit emulation.
2296 bool "x32 ABI for 64-bit mode"
2297 depends on X86_64 && IA32_EMULATION
2299 Include code to run binaries for the x32 native 32-bit ABI
2300 for 64-bit processors. An x32 process gets access to the
2301 full 64-bit register file and wide data path while leaving
2302 pointers at 32 bits for smaller memory footprint.
2304 You will need a recent binutils (2.22 or later) with
2305 elf32_x86_64 support enabled to compile a kernel with this
2310 depends on IA32_EMULATION || X86_X32
2311 select ARCH_WANT_OLD_COMPAT_IPC
2314 config COMPAT_FOR_U64_ALIGNMENT
2317 config SYSVIPC_COMPAT
2329 config HAVE_ATOMIC_IOMAP
2333 config HAVE_TEXT_POKE_SMP
2335 select STOP_MACHINE if SMP
2337 config X86_DEV_DMA_OPS
2339 depends on X86_64 || STA2X11
2341 config X86_DMA_REMAP
2345 source "net/Kconfig"
2347 source "drivers/Kconfig"
2349 source "drivers/firmware/Kconfig"
2353 source "arch/x86/Kconfig.debug"
2355 source "security/Kconfig"
2357 source "crypto/Kconfig"
2359 source "arch/x86/kvm/Kconfig"
2361 source "lib/Kconfig"
projects / firefly-linux-kernel-4.4.55.git / blob