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 CLOCKSOURCE_WATCHDOG
106 select GENERIC_CLOCKEVENTS
107 select ARCH_CLOCKSOURCE_DATA if X86_64
108 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
109 select GENERIC_TIME_VSYSCALL if X86_64
110 select KTIME_SCALAR if X86_32
111 select GENERIC_STRNCPY_FROM_USER
112 select GENERIC_STRNLEN_USER
113 select HAVE_CONTEXT_TRACKING if X86_64
114 select HAVE_IRQ_TIME_ACCOUNTING
116 select MODULES_USE_ELF_REL if X86_32
117 select MODULES_USE_ELF_RELA if X86_64
118 select CLONE_BACKWARDS if X86_32
119 select ARCH_USE_BUILTIN_BSWAP
120 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
121 select OLD_SIGACTION if X86_32
122 select COMPAT_OLD_SIGACTION if IA32_EMULATION
124 select ARCH_SUPPORTS_ATOMIC_RMW
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:
349 SGI 320/540 (Visual Workstation)
350 STA2X11-based (e.g. Northville)
351 Summit/EXA (IBM x440)
352 Unisys ES7000 IA32 series
353 Moorestown MID devices
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.
360 config X86_EXTENDED_PLATFORM
361 bool "Support for extended (non-PC) x86 platforms"
364 If you disable this option then the kernel will only support
365 standard PC platforms. (which covers the vast majority of
368 If you enable this option then you'll be able to select support
369 for the following (non-PC) 64 bit x86 platforms:
374 If you have one of these systems, or if you want to build a
375 generic distribution kernel, say Y here - otherwise say N.
377 # This is an alphabetically sorted list of 64 bit extended platforms
378 # Please maintain the alphabetic order if and when there are additions
380 bool "Numascale NumaChip"
382 depends on X86_EXTENDED_PLATFORM
385 depends on X86_X2APIC
386 depends on PCI_MMCONFIG
388 Adds support for Numascale NumaChip large-SMP systems. Needed to
389 enable more than ~168 cores.
390 If you don't have one of these, you should say N here.
394 select HYPERVISOR_GUEST
396 depends on X86_64 && PCI
397 depends on X86_EXTENDED_PLATFORM
400 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
401 supposed to run on these EM64T-based machines. Only choose this option
402 if you have one of these machines.
405 bool "SGI Ultraviolet"
407 depends on X86_EXTENDED_PLATFORM
409 depends on X86_X2APIC
411 This option is needed in order to support SGI Ultraviolet systems.
412 If you don't have one of these, you should say N here.
414 # Following is an alphabetically sorted list of 32 bit extended platforms
415 # Please maintain the alphabetic order if and when there are additions
418 bool "Goldfish (Virtual Platform)"
421 Enable support for the Goldfish virtual platform used primarily
422 for Android development. Unless you are building for the Android
423 Goldfish emulator say N here.
426 bool "CE4100 TV platform"
428 depends on PCI_GODIRECT
430 depends on X86_EXTENDED_PLATFORM
431 select X86_REBOOTFIXUPS
433 select OF_EARLY_FLATTREE
436 Select for the Intel CE media processor (CE4100) SOC.
437 This option compiles in support for the CE4100 SOC for settop
438 boxes and media devices.
440 config X86_WANT_INTEL_MID
441 bool "Intel MID platform support"
443 depends on X86_EXTENDED_PLATFORM
445 Select to build a kernel capable of supporting Intel MID platform
446 systems which do not have the PCI legacy interfaces (Moorestown,
447 Medfield). If you are building for a PC class system say N here.
449 if X86_WANT_INTEL_MID
455 bool "Medfield MID platform"
458 depends on X86_IO_APIC
466 select X86_PLATFORM_DEVICES
467 select MFD_INTEL_MSIC
469 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
470 Internet Device(MID) platform.
471 Unlike standard x86 PCs, Medfield does not have many legacy devices
472 nor standard legacy replacement devices/features. e.g. Medfield does
473 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
477 config X86_INTEL_LPSS
478 bool "Intel Low Power Subsystem Support"
482 Select to build support for Intel Low Power Subsystem such as
483 found on Intel Lynxpoint PCH. Selecting this option enables
484 things like clock tree (common clock framework) which are needed
485 by the LPSS peripheral drivers.
488 bool "RDC R-321x SoC"
490 depends on X86_EXTENDED_PLATFORM
492 select X86_REBOOTFIXUPS
494 This option is needed for RDC R-321x system-on-chip, also known
496 If you don't have one of these chips, you should say N here.
498 config X86_32_NON_STANDARD
499 bool "Support non-standard 32-bit SMP architectures"
500 depends on X86_32 && SMP
501 depends on X86_EXTENDED_PLATFORM
503 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
504 STA2X11, default subarchitectures. It is intended for a generic
505 binary kernel. If you select them all, kernel will probe it
506 one by one and will fallback to default.
508 # Alphabetically sorted list of Non standard 32 bit platforms
511 bool "NUMAQ (IBM/Sequent)"
512 depends on X86_32_NON_STANDARD
517 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
518 NUMA multiquad box. This changes the way that processors are
519 bootstrapped, and uses Clustered Logical APIC addressing mode instead
520 of Flat Logical. You will need a new lynxer.elf file to flash your
521 firmware with - send email to <Martin.Bligh@us.ibm.com>.
523 config X86_SUPPORTS_MEMORY_FAILURE
525 # MCE code calls memory_failure():
527 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
528 depends on !X86_NUMAQ
529 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
530 depends on X86_64 || !SPARSEMEM
531 select ARCH_SUPPORTS_MEMORY_FAILURE
534 bool "SGI 320/540 (Visual Workstation)"
535 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
536 depends on X86_32_NON_STANDARD
538 The SGI Visual Workstation series is an IA32-based workstation
539 based on SGI systems chips with some legacy PC hardware attached.
541 Say Y here to create a kernel to run on the SGI 320 or 540.
543 A kernel compiled for the Visual Workstation will run on general
544 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
547 bool "STA2X11 Companion Chip Support"
548 depends on X86_32_NON_STANDARD && PCI
549 select X86_DEV_DMA_OPS
553 select ARCH_REQUIRE_GPIOLIB
556 This adds support for boards based on the STA2X11 IO-Hub,
557 a.k.a. "ConneXt". The chip is used in place of the standard
558 PC chipset, so all "standard" peripherals are missing. If this
559 option is selected the kernel will still be able to boot on
560 standard PC machines.
563 bool "Summit/EXA (IBM x440)"
564 depends on X86_32_NON_STANDARD
566 This option is needed for IBM systems that use the Summit/EXA chipset.
567 In particular, it is needed for the x440.
570 bool "Unisys ES7000 IA32 series"
571 depends on X86_32_NON_STANDARD && X86_BIGSMP
573 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
574 supposed to run on an IA32-based Unisys ES7000 system.
577 tristate "Eurobraille/Iris poweroff module"
580 The Iris machines from EuroBraille do not have APM or ACPI support
581 to shut themselves down properly. A special I/O sequence is
582 needed to do so, which is what this module does at
585 This is only for Iris machines from EuroBraille.
589 config SCHED_OMIT_FRAME_POINTER
591 prompt "Single-depth WCHAN output"
594 Calculate simpler /proc/<PID>/wchan values. If this option
595 is disabled then wchan values will recurse back to the
596 caller function. This provides more accurate wchan values,
597 at the expense of slightly more scheduling overhead.
599 If in doubt, say "Y".
601 menuconfig HYPERVISOR_GUEST
602 bool "Linux guest support"
604 Say Y here to enable options for running Linux under various hyper-
605 visors. This option enables basic hypervisor detection and platform
608 If you say N, all options in this submenu will be skipped and
609 disabled, and Linux guest support won't be built in.
614 bool "Enable paravirtualization code"
616 This changes the kernel so it can modify itself when it is run
617 under a hypervisor, potentially improving performance significantly
618 over full virtualization. However, when run without a hypervisor
619 the kernel is theoretically slower and slightly larger.
621 config PARAVIRT_DEBUG
622 bool "paravirt-ops debugging"
623 depends on PARAVIRT && DEBUG_KERNEL
625 Enable to debug paravirt_ops internals. Specifically, BUG if
626 a paravirt_op is missing when it is called.
628 config PARAVIRT_SPINLOCKS
629 bool "Paravirtualization layer for spinlocks"
630 depends on PARAVIRT && SMP
632 Paravirtualized spinlocks allow a pvops backend to replace the
633 spinlock implementation with something virtualization-friendly
634 (for example, block the virtual CPU rather than spinning).
636 Unfortunately the downside is an up to 5% performance hit on
637 native kernels, with various workloads.
639 If you are unsure how to answer this question, answer N.
641 source "arch/x86/xen/Kconfig"
644 bool "KVM Guest support (including kvmclock)"
646 select PARAVIRT_CLOCK
649 This option enables various optimizations for running under the KVM
650 hypervisor. It includes a paravirtualized clock, so that instead
651 of relying on a PIT (or probably other) emulation by the
652 underlying device model, the host provides the guest with
653 timing infrastructure such as time of day, and system time
655 source "arch/x86/lguest/Kconfig"
657 config PARAVIRT_TIME_ACCOUNTING
658 bool "Paravirtual steal time accounting"
662 Select this option to enable fine granularity task steal time
663 accounting. Time spent executing other tasks in parallel with
664 the current vCPU is discounted from the vCPU power. To account for
665 that, there can be a small performance impact.
667 If in doubt, say N here.
669 config PARAVIRT_CLOCK
672 endif #HYPERVISOR_GUEST
680 This option adds a kernel parameter 'memtest', which allows memtest
682 memtest=0, mean disabled; -- default
683 memtest=1, mean do 1 test pattern;
685 memtest=4, mean do 4 test patterns.
686 If you are unsure how to answer this question, answer N.
688 config X86_SUMMIT_NUMA
690 depends on X86_32 && NUMA && X86_32_NON_STANDARD
692 config X86_CYCLONE_TIMER
694 depends on X86_SUMMIT
696 source "arch/x86/Kconfig.cpu"
700 prompt "HPET Timer Support" if X86_32
702 Use the IA-PC HPET (High Precision Event Timer) to manage
703 time in preference to the PIT and RTC, if a HPET is
705 HPET is the next generation timer replacing legacy 8254s.
706 The HPET provides a stable time base on SMP
707 systems, unlike the TSC, but it is more expensive to access,
708 as it is off-chip. You can find the HPET spec at
709 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
711 You can safely choose Y here. However, HPET will only be
712 activated if the platform and the BIOS support this feature.
713 Otherwise the 8254 will be used for timing services.
715 Choose N to continue using the legacy 8254 timer.
717 config HPET_EMULATE_RTC
719 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
722 def_bool y if X86_INTEL_MID
723 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
725 depends on X86_INTEL_MID && SFI
727 APB timer is the replacement for 8254, HPET on X86 MID platforms.
728 The APBT provides a stable time base on SMP
729 systems, unlike the TSC, but it is more expensive to access,
730 as it is off-chip. APB timers are always running regardless of CPU
731 C states, they are used as per CPU clockevent device when possible.
733 # Mark as expert because too many people got it wrong.
734 # The code disables itself when not needed.
737 bool "Enable DMI scanning" if EXPERT
739 Enabled scanning of DMI to identify machine quirks. Say Y
740 here unless you have verified that your setup is not
741 affected by entries in the DMI blacklist. Required by PNP
745 bool "GART IOMMU support" if EXPERT
748 depends on X86_64 && PCI && AMD_NB
750 Support for full DMA access of devices with 32bit memory access only
751 on systems with more than 3GB. This is usually needed for USB,
752 sound, many IDE/SATA chipsets and some other devices.
753 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
754 based hardware IOMMU and a software bounce buffer based IOMMU used
755 on Intel systems and as fallback.
756 The code is only active when needed (enough memory and limited
757 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
761 bool "IBM Calgary IOMMU support"
763 depends on X86_64 && PCI
765 Support for hardware IOMMUs in IBM's xSeries x366 and x460
766 systems. Needed to run systems with more than 3GB of memory
767 properly with 32-bit PCI devices that do not support DAC
768 (Double Address Cycle). Calgary also supports bus level
769 isolation, where all DMAs pass through the IOMMU. This
770 prevents them from going anywhere except their intended
771 destination. This catches hard-to-find kernel bugs and
772 mis-behaving drivers and devices that do not use the DMA-API
773 properly to set up their DMA buffers. The IOMMU can be
774 turned off at boot time with the iommu=off parameter.
775 Normally the kernel will make the right choice by itself.
778 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
780 prompt "Should Calgary be enabled by default?"
781 depends on CALGARY_IOMMU
783 Should Calgary be enabled by default? if you choose 'y', Calgary
784 will be used (if it exists). If you choose 'n', Calgary will not be
785 used even if it exists. If you choose 'n' and would like to use
786 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
789 # need this always selected by IOMMU for the VIA workaround
793 Support for software bounce buffers used on x86-64 systems
794 which don't have a hardware IOMMU. Using this PCI devices
795 which can only access 32-bits of memory can be used on systems
796 with more than 3 GB of memory.
801 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
804 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
805 depends on X86_64 && SMP && DEBUG_KERNEL
806 select CPUMASK_OFFSTACK
808 Enable maximum number of CPUS and NUMA Nodes for this architecture.
812 int "Maximum number of CPUs" if SMP && !MAXSMP
813 range 2 8 if SMP && X86_32 && !X86_BIGSMP
814 range 2 512 if SMP && !MAXSMP
816 default "4096" if MAXSMP
817 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
820 This allows you to specify the maximum number of CPUs which this
821 kernel will support. The maximum supported value is 512 and the
822 minimum value which makes sense is 2.
824 This is purely to save memory - each supported CPU adds
825 approximately eight kilobytes to the kernel image.
828 bool "SMT (Hyperthreading) scheduler support"
831 SMT scheduler support improves the CPU scheduler's decision making
832 when dealing with Intel Pentium 4 chips with HyperThreading at a
833 cost of slightly increased overhead in some places. If unsure say
838 prompt "Multi-core scheduler support"
841 Multi-core scheduler support improves the CPU scheduler's decision
842 making when dealing with multi-core CPU chips at a cost of slightly
843 increased overhead in some places. If unsure say N here.
845 source "kernel/Kconfig.preempt"
848 bool "Local APIC support on uniprocessors"
849 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
851 A local APIC (Advanced Programmable Interrupt Controller) is an
852 integrated interrupt controller in the CPU. If you have a single-CPU
853 system which has a processor with a local APIC, you can say Y here to
854 enable and use it. If you say Y here even though your machine doesn't
855 have a local APIC, then the kernel will still run with no slowdown at
856 all. The local APIC supports CPU-generated self-interrupts (timer,
857 performance counters), and the NMI watchdog which detects hard
861 bool "IO-APIC support on uniprocessors"
862 depends on X86_UP_APIC
864 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
865 SMP-capable replacement for PC-style interrupt controllers. Most
866 SMP systems and many recent uniprocessor systems have one.
868 If you have a single-CPU system with an IO-APIC, you can say Y here
869 to use it. If you say Y here even though your machine doesn't have
870 an IO-APIC, then the kernel will still run with no slowdown at all.
872 config X86_LOCAL_APIC
874 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
878 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
880 config X86_VISWS_APIC
882 depends on X86_32 && X86_VISWS
884 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
885 bool "Reroute for broken boot IRQs"
886 depends on X86_IO_APIC
888 This option enables a workaround that fixes a source of
889 spurious interrupts. This is recommended when threaded
890 interrupt handling is used on systems where the generation of
891 superfluous "boot interrupts" cannot be disabled.
893 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
894 entry in the chipset's IO-APIC is masked (as, e.g. the RT
895 kernel does during interrupt handling). On chipsets where this
896 boot IRQ generation cannot be disabled, this workaround keeps
897 the original IRQ line masked so that only the equivalent "boot
898 IRQ" is delivered to the CPUs. The workaround also tells the
899 kernel to set up the IRQ handler on the boot IRQ line. In this
900 way only one interrupt is delivered to the kernel. Otherwise
901 the spurious second interrupt may cause the kernel to bring
902 down (vital) interrupt lines.
904 Only affects "broken" chipsets. Interrupt sharing may be
905 increased on these systems.
908 bool "Machine Check / overheating reporting"
911 Machine Check support allows the processor to notify the
912 kernel if it detects a problem (e.g. overheating, data corruption).
913 The action the kernel takes depends on the severity of the problem,
914 ranging from warning messages to halting the machine.
918 prompt "Intel MCE features"
919 depends on X86_MCE && X86_LOCAL_APIC
921 Additional support for intel specific MCE features such as
926 prompt "AMD MCE features"
927 depends on X86_MCE && X86_LOCAL_APIC
929 Additional support for AMD specific MCE features such as
930 the DRAM Error Threshold.
932 config X86_ANCIENT_MCE
933 bool "Support for old Pentium 5 / WinChip machine checks"
934 depends on X86_32 && X86_MCE
936 Include support for machine check handling on old Pentium 5 or WinChip
937 systems. These typically need to be enabled explicitely on the command
940 config X86_MCE_THRESHOLD
941 depends on X86_MCE_AMD || X86_MCE_INTEL
944 config X86_MCE_INJECT
946 tristate "Machine check injector support"
948 Provide support for injecting machine checks for testing purposes.
949 If you don't know what a machine check is and you don't do kernel
950 QA it is safe to say n.
952 config X86_THERMAL_VECTOR
954 depends on X86_MCE_INTEL
957 bool "Enable VM86 support" if EXPERT
961 This option is required by programs like DOSEMU to run
962 16-bit real mode legacy code on x86 processors. It also may
963 be needed by software like XFree86 to initialize some video
964 cards via BIOS. Disabling this option saves about 6K.
967 bool "Enable support for 16-bit segments" if EXPERT
970 This option is required by programs like Wine to run 16-bit
971 protected mode legacy code on x86 processors. Disabling
972 this option saves about 300 bytes on i386, or around 6K text
973 plus 16K runtime memory on x86-64,
977 depends on X86_16BIT && X86_32
981 depends on X86_16BIT && X86_64
984 tristate "Toshiba Laptop support"
987 This adds a driver to safely access the System Management Mode of
988 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
989 not work on models with a Phoenix BIOS. The System Management Mode
990 is used to set the BIOS and power saving options on Toshiba portables.
992 For information on utilities to make use of this driver see the
993 Toshiba Linux utilities web site at:
994 <http://www.buzzard.org.uk/toshiba/>.
996 Say Y if you intend to run this kernel on a Toshiba portable.
1000 tristate "Dell laptop support"
1003 This adds a driver to safely access the System Management Mode
1004 of the CPU on the Dell Inspiron 8000. The System Management Mode
1005 is used to read cpu temperature and cooling fan status and to
1006 control the fans on the I8K portables.
1008 This driver has been tested only on the Inspiron 8000 but it may
1009 also work with other Dell laptops. You can force loading on other
1010 models by passing the parameter `force=1' to the module. Use at
1013 For information on utilities to make use of this driver see the
1014 I8K Linux utilities web site at:
1015 <http://people.debian.org/~dz/i8k/>
1017 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1020 config X86_REBOOTFIXUPS
1021 bool "Enable X86 board specific fixups for reboot"
1024 This enables chipset and/or board specific fixups to be done
1025 in order to get reboot to work correctly. This is only needed on
1026 some combinations of hardware and BIOS. The symptom, for which
1027 this config is intended, is when reboot ends with a stalled/hung
1030 Currently, the only fixup is for the Geode machines using
1031 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1033 Say Y if you want to enable the fixup. Currently, it's safe to
1034 enable this option even if you don't need it.
1038 tristate "CPU microcode loading support"
1042 If you say Y here, you will be able to update the microcode on
1043 certain Intel and AMD processors. The Intel support is for the
1044 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1045 Xeon etc. The AMD support is for families 0x10 and later. You will
1046 obviously need the actual microcode binary data itself which is not
1047 shipped with the Linux kernel.
1049 This option selects the general module only, you need to select
1050 at least one vendor specific module as well.
1052 To compile this driver as a module, choose M here: the module
1053 will be called microcode.
1055 config MICROCODE_INTEL
1056 bool "Intel microcode loading support"
1057 depends on MICROCODE
1061 This options enables microcode patch loading support for Intel
1064 For latest news and information on obtaining all the required
1065 Intel ingredients for this driver, check:
1066 <http://www.urbanmyth.org/microcode/>.
1068 config MICROCODE_AMD
1069 bool "AMD microcode loading support"
1070 depends on MICROCODE
1073 If you select this option, microcode patch loading support for AMD
1074 processors will be enabled.
1076 config MICROCODE_OLD_INTERFACE
1078 depends on MICROCODE
1080 config MICROCODE_INTEL_LIB
1082 depends on MICROCODE_INTEL
1084 config MICROCODE_INTEL_EARLY
1085 bool "Early load microcode"
1086 depends on MICROCODE_INTEL && BLK_DEV_INITRD
1089 This option provides functionality to read additional microcode data
1090 at the beginning of initrd image. The data tells kernel to load
1091 microcode to CPU's as early as possible. No functional change if no
1092 microcode data is glued to the initrd, therefore it's safe to say Y.
1094 config MICROCODE_EARLY
1096 depends on MICROCODE_INTEL_EARLY
1099 tristate "/dev/cpu/*/msr - Model-specific register support"
1101 This device gives privileged processes access to the x86
1102 Model-Specific Registers (MSRs). It is a character device with
1103 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1104 MSR accesses are directed to a specific CPU on multi-processor
1108 tristate "/dev/cpu/*/cpuid - CPU information support"
1110 This device gives processes access to the x86 CPUID instruction to
1111 be executed on a specific processor. It is a character device
1112 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1116 prompt "High Memory Support"
1117 default HIGHMEM64G if X86_NUMAQ
1123 depends on !X86_NUMAQ
1125 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1126 However, the address space of 32-bit x86 processors is only 4
1127 Gigabytes large. That means that, if you have a large amount of
1128 physical memory, not all of it can be "permanently mapped" by the
1129 kernel. The physical memory that's not permanently mapped is called
1132 If you are compiling a kernel which will never run on a machine with
1133 more than 1 Gigabyte total physical RAM, answer "off" here (default
1134 choice and suitable for most users). This will result in a "3GB/1GB"
1135 split: 3GB are mapped so that each process sees a 3GB virtual memory
1136 space and the remaining part of the 4GB virtual memory space is used
1137 by the kernel to permanently map as much physical memory as
1140 If the machine has between 1 and 4 Gigabytes physical RAM, then
1143 If more than 4 Gigabytes is used then answer "64GB" here. This
1144 selection turns Intel PAE (Physical Address Extension) mode on.
1145 PAE implements 3-level paging on IA32 processors. PAE is fully
1146 supported by Linux, PAE mode is implemented on all recent Intel
1147 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1148 then the kernel will not boot on CPUs that don't support PAE!
1150 The actual amount of total physical memory will either be
1151 auto detected or can be forced by using a kernel command line option
1152 such as "mem=256M". (Try "man bootparam" or see the documentation of
1153 your boot loader (lilo or loadlin) about how to pass options to the
1154 kernel at boot time.)
1156 If unsure, say "off".
1160 depends on !X86_NUMAQ
1162 Select this if you have a 32-bit processor and between 1 and 4
1163 gigabytes of physical RAM.
1170 Select this if you have a 32-bit processor and more than 4
1171 gigabytes of physical RAM.
1176 prompt "Memory split" if EXPERT
1180 Select the desired split between kernel and user memory.
1182 If the address range available to the kernel is less than the
1183 physical memory installed, the remaining memory will be available
1184 as "high memory". Accessing high memory is a little more costly
1185 than low memory, as it needs to be mapped into the kernel first.
1186 Note that increasing the kernel address space limits the range
1187 available to user programs, making the address space there
1188 tighter. Selecting anything other than the default 3G/1G split
1189 will also likely make your kernel incompatible with binary-only
1192 If you are not absolutely sure what you are doing, leave this
1196 bool "3G/1G user/kernel split"
1197 config VMSPLIT_3G_OPT
1199 bool "3G/1G user/kernel split (for full 1G low memory)"
1201 bool "2G/2G user/kernel split"
1202 config VMSPLIT_2G_OPT
1204 bool "2G/2G user/kernel split (for full 2G low memory)"
1206 bool "1G/3G user/kernel split"
1211 default 0xB0000000 if VMSPLIT_3G_OPT
1212 default 0x80000000 if VMSPLIT_2G
1213 default 0x78000000 if VMSPLIT_2G_OPT
1214 default 0x40000000 if VMSPLIT_1G
1220 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1223 bool "PAE (Physical Address Extension) Support"
1224 depends on X86_32 && !HIGHMEM4G
1226 PAE is required for NX support, and furthermore enables
1227 larger swapspace support for non-overcommit purposes. It
1228 has the cost of more pagetable lookup overhead, and also
1229 consumes more pagetable space per process.
1231 config ARCH_PHYS_ADDR_T_64BIT
1233 depends on X86_64 || X86_PAE
1235 config ARCH_DMA_ADDR_T_64BIT
1237 depends on X86_64 || HIGHMEM64G
1239 config DIRECT_GBPAGES
1240 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1244 Allow the kernel linear mapping to use 1GB pages on CPUs that
1245 support it. This can improve the kernel's performance a tiny bit by
1246 reducing TLB pressure. If in doubt, say "Y".
1248 # Common NUMA Features
1250 bool "Numa Memory Allocation and Scheduler Support"
1252 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI))
1253 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1255 Enable NUMA (Non Uniform Memory Access) support.
1257 The kernel will try to allocate memory used by a CPU on the
1258 local memory controller of the CPU and add some more
1259 NUMA awareness to the kernel.
1261 For 64-bit this is recommended if the system is Intel Core i7
1262 (or later), AMD Opteron, or EM64T NUMA.
1264 For 32-bit this is only needed on (rare) 32-bit-only platforms
1265 that support NUMA topologies, such as NUMAQ / Summit, or if you
1266 boot a 32-bit kernel on a 64-bit NUMA platform.
1268 Otherwise, you should say N.
1270 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1271 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1275 prompt "Old style AMD Opteron NUMA detection"
1276 depends on X86_64 && NUMA && PCI
1278 Enable AMD NUMA node topology detection. You should say Y here if
1279 you have a multi processor AMD system. This uses an old method to
1280 read the NUMA configuration directly from the builtin Northbridge
1281 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1282 which also takes priority if both are compiled in.
1284 config X86_64_ACPI_NUMA
1286 prompt "ACPI NUMA detection"
1287 depends on X86_64 && NUMA && ACPI && PCI
1290 Enable ACPI SRAT based node topology detection.
1292 # Some NUMA nodes have memory ranges that span
1293 # other nodes. Even though a pfn is valid and
1294 # between a node's start and end pfns, it may not
1295 # reside on that node. See memmap_init_zone()
1297 config NODES_SPAN_OTHER_NODES
1299 depends on X86_64_ACPI_NUMA
1302 bool "NUMA emulation"
1305 Enable NUMA emulation. A flat machine will be split
1306 into virtual nodes when booted with "numa=fake=N", where N is the
1307 number of nodes. This is only useful for debugging.
1310 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1312 default "10" if MAXSMP
1313 default "6" if X86_64
1314 default "4" if X86_NUMAQ
1316 depends on NEED_MULTIPLE_NODES
1318 Specify the maximum number of NUMA Nodes available on the target
1319 system. Increases memory reserved to accommodate various tables.
1321 config ARCH_HAVE_MEMORY_PRESENT
1323 depends on X86_32 && DISCONTIGMEM
1325 config NEED_NODE_MEMMAP_SIZE
1327 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1329 config ARCH_FLATMEM_ENABLE
1331 depends on X86_32 && !NUMA
1333 config ARCH_DISCONTIGMEM_ENABLE
1335 depends on NUMA && X86_32
1337 config ARCH_DISCONTIGMEM_DEFAULT
1339 depends on NUMA && X86_32
1341 config ARCH_SPARSEMEM_ENABLE
1343 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1344 select SPARSEMEM_STATIC if X86_32
1345 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1347 config ARCH_SPARSEMEM_DEFAULT
1351 config ARCH_SELECT_MEMORY_MODEL
1353 depends on ARCH_SPARSEMEM_ENABLE
1355 config ARCH_MEMORY_PROBE
1357 depends on X86_64 && MEMORY_HOTPLUG
1359 config ARCH_PROC_KCORE_TEXT
1361 depends on X86_64 && PROC_KCORE
1363 config ILLEGAL_POINTER_VALUE
1366 default 0xdead000000000000 if X86_64
1371 bool "Allocate 3rd-level pagetables from highmem"
1374 The VM uses one page table entry for each page of physical memory.
1375 For systems with a lot of RAM, this can be wasteful of precious
1376 low memory. Setting this option will put user-space page table
1377 entries in high memory.
1379 config X86_CHECK_BIOS_CORRUPTION
1380 bool "Check for low memory corruption"
1382 Periodically check for memory corruption in low memory, which
1383 is suspected to be caused by BIOS. Even when enabled in the
1384 configuration, it is disabled at runtime. Enable it by
1385 setting "memory_corruption_check=1" on the kernel command
1386 line. By default it scans the low 64k of memory every 60
1387 seconds; see the memory_corruption_check_size and
1388 memory_corruption_check_period parameters in
1389 Documentation/kernel-parameters.txt to adjust this.
1391 When enabled with the default parameters, this option has
1392 almost no overhead, as it reserves a relatively small amount
1393 of memory and scans it infrequently. It both detects corruption
1394 and prevents it from affecting the running system.
1396 It is, however, intended as a diagnostic tool; if repeatable
1397 BIOS-originated corruption always affects the same memory,
1398 you can use memmap= to prevent the kernel from using that
1401 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1402 bool "Set the default setting of memory_corruption_check"
1403 depends on X86_CHECK_BIOS_CORRUPTION
1406 Set whether the default state of memory_corruption_check is
1409 config X86_RESERVE_LOW
1410 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1414 Specify the amount of low memory to reserve for the BIOS.
1416 The first page contains BIOS data structures that the kernel
1417 must not use, so that page must always be reserved.
1419 By default we reserve the first 64K of physical RAM, as a
1420 number of BIOSes are known to corrupt that memory range
1421 during events such as suspend/resume or monitor cable
1422 insertion, so it must not be used by the kernel.
1424 You can set this to 4 if you are absolutely sure that you
1425 trust the BIOS to get all its memory reservations and usages
1426 right. If you know your BIOS have problems beyond the
1427 default 64K area, you can set this to 640 to avoid using the
1428 entire low memory range.
1430 If you have doubts about the BIOS (e.g. suspend/resume does
1431 not work or there's kernel crashes after certain hardware
1432 hotplug events) then you might want to enable
1433 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1434 typical corruption patterns.
1436 Leave this to the default value of 64 if you are unsure.
1438 config MATH_EMULATION
1440 prompt "Math emulation" if X86_32
1442 Linux can emulate a math coprocessor (used for floating point
1443 operations) if you don't have one. 486DX and Pentium processors have
1444 a math coprocessor built in, 486SX and 386 do not, unless you added
1445 a 487DX or 387, respectively. (The messages during boot time can
1446 give you some hints here ["man dmesg"].) Everyone needs either a
1447 coprocessor or this emulation.
1449 If you don't have a math coprocessor, you need to say Y here; if you
1450 say Y here even though you have a coprocessor, the coprocessor will
1451 be used nevertheless. (This behavior can be changed with the kernel
1452 command line option "no387", which comes handy if your coprocessor
1453 is broken. Try "man bootparam" or see the documentation of your boot
1454 loader (lilo or loadlin) about how to pass options to the kernel at
1455 boot time.) This means that it is a good idea to say Y here if you
1456 intend to use this kernel on different machines.
1458 More information about the internals of the Linux math coprocessor
1459 emulation can be found in <file:arch/x86/math-emu/README>.
1461 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1462 kernel, it won't hurt.
1466 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1468 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1469 the Memory Type Range Registers (MTRRs) may be used to control
1470 processor access to memory ranges. This is most useful if you have
1471 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1472 allows bus write transfers to be combined into a larger transfer
1473 before bursting over the PCI/AGP bus. This can increase performance
1474 of image write operations 2.5 times or more. Saying Y here creates a
1475 /proc/mtrr file which may be used to manipulate your processor's
1476 MTRRs. Typically the X server should use this.
1478 This code has a reasonably generic interface so that similar
1479 control registers on other processors can be easily supported
1482 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1483 Registers (ARRs) which provide a similar functionality to MTRRs. For
1484 these, the ARRs are used to emulate the MTRRs.
1485 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1486 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1487 write-combining. All of these processors are supported by this code
1488 and it makes sense to say Y here if you have one of them.
1490 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1491 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1492 can lead to all sorts of problems, so it's good to say Y here.
1494 You can safely say Y even if your machine doesn't have MTRRs, you'll
1495 just add about 9 KB to your kernel.
1497 See <file:Documentation/x86/mtrr.txt> for more information.
1499 config MTRR_SANITIZER
1501 prompt "MTRR cleanup support"
1504 Convert MTRR layout from continuous to discrete, so X drivers can
1505 add writeback entries.
1507 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1508 The largest mtrr entry size for a continuous block can be set with
1513 config MTRR_SANITIZER_ENABLE_DEFAULT
1514 int "MTRR cleanup enable value (0-1)"
1517 depends on MTRR_SANITIZER
1519 Enable mtrr cleanup default value
1521 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1522 int "MTRR cleanup spare reg num (0-7)"
1525 depends on MTRR_SANITIZER
1527 mtrr cleanup spare entries default, it can be changed via
1528 mtrr_spare_reg_nr=N on the kernel command line.
1532 prompt "x86 PAT support" if EXPERT
1535 Use PAT attributes to setup page level cache control.
1537 PATs are the modern equivalents of MTRRs and are much more
1538 flexible than MTRRs.
1540 Say N here if you see bootup problems (boot crash, boot hang,
1541 spontaneous reboots) or a non-working video driver.
1545 config ARCH_USES_PG_UNCACHED
1551 prompt "x86 architectural random number generator" if EXPERT
1553 Enable the x86 architectural RDRAND instruction
1554 (Intel Bull Mountain technology) to generate random numbers.
1555 If supported, this is a high bandwidth, cryptographically
1556 secure hardware random number generator.
1560 prompt "Supervisor Mode Access Prevention" if EXPERT
1562 Supervisor Mode Access Prevention (SMAP) is a security
1563 feature in newer Intel processors. There is a small
1564 performance cost if this enabled and turned on; there is
1565 also a small increase in the kernel size if this is enabled.
1570 bool "EFI runtime service support"
1574 This enables the kernel to use EFI runtime services that are
1575 available (such as the EFI variable services).
1577 This option is only useful on systems that have EFI firmware.
1578 In addition, you should use the latest ELILO loader available
1579 at <http://elilo.sourceforge.net> in order to take advantage
1580 of EFI runtime services. However, even with this option, the
1581 resultant kernel should continue to boot on existing non-EFI
1585 bool "EFI stub support"
1589 This kernel feature allows a bzImage to be loaded directly
1590 by EFI firmware without the use of a bootloader.
1592 See Documentation/x86/efi-stub.txt for more information.
1596 prompt "Enable seccomp to safely compute untrusted bytecode"
1598 This kernel feature is useful for number crunching applications
1599 that may need to compute untrusted bytecode during their
1600 execution. By using pipes or other transports made available to
1601 the process as file descriptors supporting the read/write
1602 syscalls, it's possible to isolate those applications in
1603 their own address space using seccomp. Once seccomp is
1604 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1605 and the task is only allowed to execute a few safe syscalls
1606 defined by each seccomp mode.
1608 If unsure, say Y. Only embedded should say N here.
1610 config CC_STACKPROTECTOR
1611 bool "Enable -fstack-protector buffer overflow detection"
1613 This option turns on the -fstack-protector GCC feature. This
1614 feature puts, at the beginning of functions, a canary value on
1615 the stack just before the return address, and validates
1616 the value just before actually returning. Stack based buffer
1617 overflows (that need to overwrite this return address) now also
1618 overwrite the canary, which gets detected and the attack is then
1619 neutralized via a kernel panic.
1621 This feature requires gcc version 4.2 or above, or a distribution
1622 gcc with the feature backported. Older versions are automatically
1623 detected and for those versions, this configuration option is
1624 ignored. (and a warning is printed during bootup)
1626 source kernel/Kconfig.hz
1629 bool "kexec system call"
1631 kexec is a system call that implements the ability to shutdown your
1632 current kernel, and to start another kernel. It is like a reboot
1633 but it is independent of the system firmware. And like a reboot
1634 you can start any kernel with it, not just Linux.
1636 The name comes from the similarity to the exec system call.
1638 It is an ongoing process to be certain the hardware in a machine
1639 is properly shutdown, so do not be surprised if this code does not
1640 initially work for you. It may help to enable device hotplugging
1641 support. As of this writing the exact hardware interface is
1642 strongly in flux, so no good recommendation can be made.
1645 bool "kernel crash dumps"
1646 depends on X86_64 || (X86_32 && HIGHMEM)
1648 Generate crash dump after being started by kexec.
1649 This should be normally only set in special crash dump kernels
1650 which are loaded in the main kernel with kexec-tools into
1651 a specially reserved region and then later executed after
1652 a crash by kdump/kexec. The crash dump kernel must be compiled
1653 to a memory address not used by the main kernel or BIOS using
1654 PHYSICAL_START, or it must be built as a relocatable image
1655 (CONFIG_RELOCATABLE=y).
1656 For more details see Documentation/kdump/kdump.txt
1660 depends on KEXEC && HIBERNATION
1662 Jump between original kernel and kexeced kernel and invoke
1663 code in physical address mode via KEXEC
1665 config PHYSICAL_START
1666 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1669 This gives the physical address where the kernel is loaded.
1671 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1672 bzImage will decompress itself to above physical address and
1673 run from there. Otherwise, bzImage will run from the address where
1674 it has been loaded by the boot loader and will ignore above physical
1677 In normal kdump cases one does not have to set/change this option
1678 as now bzImage can be compiled as a completely relocatable image
1679 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1680 address. This option is mainly useful for the folks who don't want
1681 to use a bzImage for capturing the crash dump and want to use a
1682 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1683 to be specifically compiled to run from a specific memory area
1684 (normally a reserved region) and this option comes handy.
1686 So if you are using bzImage for capturing the crash dump,
1687 leave the value here unchanged to 0x1000000 and set
1688 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1689 for capturing the crash dump change this value to start of
1690 the reserved region. In other words, it can be set based on
1691 the "X" value as specified in the "crashkernel=YM@XM"
1692 command line boot parameter passed to the panic-ed
1693 kernel. Please take a look at Documentation/kdump/kdump.txt
1694 for more details about crash dumps.
1696 Usage of bzImage for capturing the crash dump is recommended as
1697 one does not have to build two kernels. Same kernel can be used
1698 as production kernel and capture kernel. Above option should have
1699 gone away after relocatable bzImage support is introduced. But it
1700 is present because there are users out there who continue to use
1701 vmlinux for dump capture. This option should go away down the
1704 Don't change this unless you know what you are doing.
1707 bool "Build a relocatable kernel"
1710 This builds a kernel image that retains relocation information
1711 so it can be loaded someplace besides the default 1MB.
1712 The relocations tend to make the kernel binary about 10% larger,
1713 but are discarded at runtime.
1715 One use is for the kexec on panic case where the recovery kernel
1716 must live at a different physical address than the primary
1719 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1720 it has been loaded at and the compile time physical address
1721 (CONFIG_PHYSICAL_START) is ignored.
1723 # Relocation on x86-32 needs some additional build support
1724 config X86_NEED_RELOCS
1726 depends on X86_32 && RELOCATABLE
1728 config PHYSICAL_ALIGN
1729 hex "Alignment value to which kernel should be aligned" if X86_32
1731 range 0x2000 0x1000000
1733 This value puts the alignment restrictions on physical address
1734 where kernel is loaded and run from. Kernel is compiled for an
1735 address which meets above alignment restriction.
1737 If bootloader loads the kernel at a non-aligned address and
1738 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1739 address aligned to above value and run from there.
1741 If bootloader loads the kernel at a non-aligned address and
1742 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1743 load address and decompress itself to the address it has been
1744 compiled for and run from there. The address for which kernel is
1745 compiled already meets above alignment restrictions. Hence the
1746 end result is that kernel runs from a physical address meeting
1747 above alignment restrictions.
1749 Don't change this unless you know what you are doing.
1752 bool "Support for hot-pluggable CPUs"
1753 depends on SMP && HOTPLUG
1755 Say Y here to allow turning CPUs off and on. CPUs can be
1756 controlled through /sys/devices/system/cpu.
1757 ( Note: power management support will enable this option
1758 automatically on SMP systems. )
1759 Say N if you want to disable CPU hotplug.
1761 config BOOTPARAM_HOTPLUG_CPU0
1762 bool "Set default setting of cpu0_hotpluggable"
1764 depends on HOTPLUG_CPU
1766 Set whether default state of cpu0_hotpluggable is on or off.
1768 Say Y here to enable CPU0 hotplug by default. If this switch
1769 is turned on, there is no need to give cpu0_hotplug kernel
1770 parameter and the CPU0 hotplug feature is enabled by default.
1772 Please note: there are two known CPU0 dependencies if you want
1773 to enable the CPU0 hotplug feature either by this switch or by
1774 cpu0_hotplug kernel parameter.
1776 First, resume from hibernate or suspend always starts from CPU0.
1777 So hibernate and suspend are prevented if CPU0 is offline.
1779 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1780 offline if any interrupt can not migrate out of CPU0. There may
1781 be other CPU0 dependencies.
1783 Please make sure the dependencies are under your control before
1784 you enable this feature.
1786 Say N if you don't want to enable CPU0 hotplug feature by default.
1787 You still can enable the CPU0 hotplug feature at boot by kernel
1788 parameter cpu0_hotplug.
1790 config DEBUG_HOTPLUG_CPU0
1792 prompt "Debug CPU0 hotplug"
1793 depends on HOTPLUG_CPU
1795 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1796 soon as possible and boots up userspace with CPU0 offlined. User
1797 can online CPU0 back after boot time.
1799 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1800 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1801 compilation or giving cpu0_hotplug kernel parameter at boot.
1807 prompt "Compat VDSO support"
1808 depends on X86_32 || IA32_EMULATION
1810 Map the 32-bit VDSO to the predictable old-style address too.
1812 Say N here if you are running a sufficiently recent glibc
1813 version (2.3.3 or later), to remove the high-mapped
1814 VDSO mapping and to exclusively use the randomized VDSO.
1819 bool "Built-in kernel command line"
1821 Allow for specifying boot arguments to the kernel at
1822 build time. On some systems (e.g. embedded ones), it is
1823 necessary or convenient to provide some or all of the
1824 kernel boot arguments with the kernel itself (that is,
1825 to not rely on the boot loader to provide them.)
1827 To compile command line arguments into the kernel,
1828 set this option to 'Y', then fill in the
1829 the boot arguments in CONFIG_CMDLINE.
1831 Systems with fully functional boot loaders (i.e. non-embedded)
1832 should leave this option set to 'N'.
1835 string "Built-in kernel command string"
1836 depends on CMDLINE_BOOL
1839 Enter arguments here that should be compiled into the kernel
1840 image and used at boot time. If the boot loader provides a
1841 command line at boot time, it is appended to this string to
1842 form the full kernel command line, when the system boots.
1844 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1845 change this behavior.
1847 In most cases, the command line (whether built-in or provided
1848 by the boot loader) should specify the device for the root
1851 config CMDLINE_OVERRIDE
1852 bool "Built-in command line overrides boot loader arguments"
1853 depends on CMDLINE_BOOL
1855 Set this option to 'Y' to have the kernel ignore the boot loader
1856 command line, and use ONLY the built-in command line.
1858 This is used to work around broken boot loaders. This should
1859 be set to 'N' under normal conditions.
1863 config ARCH_ENABLE_MEMORY_HOTPLUG
1865 depends on X86_64 || (X86_32 && HIGHMEM)
1867 config ARCH_ENABLE_MEMORY_HOTREMOVE
1869 depends on MEMORY_HOTPLUG
1871 config USE_PERCPU_NUMA_NODE_ID
1875 menu "Power management and ACPI options"
1877 config ARCH_HIBERNATION_HEADER
1879 depends on X86_64 && HIBERNATION
1881 source "kernel/power/Kconfig"
1883 source "drivers/acpi/Kconfig"
1885 source "drivers/sfi/Kconfig"
1892 tristate "APM (Advanced Power Management) BIOS support"
1893 depends on X86_32 && PM_SLEEP
1895 APM is a BIOS specification for saving power using several different
1896 techniques. This is mostly useful for battery powered laptops with
1897 APM compliant BIOSes. If you say Y here, the system time will be
1898 reset after a RESUME operation, the /proc/apm device will provide
1899 battery status information, and user-space programs will receive
1900 notification of APM "events" (e.g. battery status change).
1902 If you select "Y" here, you can disable actual use of the APM
1903 BIOS by passing the "apm=off" option to the kernel at boot time.
1905 Note that the APM support is almost completely disabled for
1906 machines with more than one CPU.
1908 In order to use APM, you will need supporting software. For location
1909 and more information, read <file:Documentation/power/apm-acpi.txt>
1910 and the Battery Powered Linux mini-HOWTO, available from
1911 <http://www.tldp.org/docs.html#howto>.
1913 This driver does not spin down disk drives (see the hdparm(8)
1914 manpage ("man 8 hdparm") for that), and it doesn't turn off
1915 VESA-compliant "green" monitors.
1917 This driver does not support the TI 4000M TravelMate and the ACER
1918 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1919 desktop machines also don't have compliant BIOSes, and this driver
1920 may cause those machines to panic during the boot phase.
1922 Generally, if you don't have a battery in your machine, there isn't
1923 much point in using this driver and you should say N. If you get
1924 random kernel OOPSes or reboots that don't seem to be related to
1925 anything, try disabling/enabling this option (or disabling/enabling
1928 Some other things you should try when experiencing seemingly random,
1931 1) make sure that you have enough swap space and that it is
1933 2) pass the "no-hlt" option to the kernel
1934 3) switch on floating point emulation in the kernel and pass
1935 the "no387" option to the kernel
1936 4) pass the "floppy=nodma" option to the kernel
1937 5) pass the "mem=4M" option to the kernel (thereby disabling
1938 all but the first 4 MB of RAM)
1939 6) make sure that the CPU is not over clocked.
1940 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1941 8) disable the cache from your BIOS settings
1942 9) install a fan for the video card or exchange video RAM
1943 10) install a better fan for the CPU
1944 11) exchange RAM chips
1945 12) exchange the motherboard.
1947 To compile this driver as a module, choose M here: the
1948 module will be called apm.
1952 config APM_IGNORE_USER_SUSPEND
1953 bool "Ignore USER SUSPEND"
1955 This option will ignore USER SUSPEND requests. On machines with a
1956 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1957 series notebooks, it is necessary to say Y because of a BIOS bug.
1959 config APM_DO_ENABLE
1960 bool "Enable PM at boot time"
1962 Enable APM features at boot time. From page 36 of the APM BIOS
1963 specification: "When disabled, the APM BIOS does not automatically
1964 power manage devices, enter the Standby State, enter the Suspend
1965 State, or take power saving steps in response to CPU Idle calls."
1966 This driver will make CPU Idle calls when Linux is idle (unless this
1967 feature is turned off -- see "Do CPU IDLE calls", below). This
1968 should always save battery power, but more complicated APM features
1969 will be dependent on your BIOS implementation. You may need to turn
1970 this option off if your computer hangs at boot time when using APM
1971 support, or if it beeps continuously instead of suspending. Turn
1972 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1973 T400CDT. This is off by default since most machines do fine without
1978 bool "Make CPU Idle calls when idle"
1980 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1981 On some machines, this can activate improved power savings, such as
1982 a slowed CPU clock rate, when the machine is idle. These idle calls
1983 are made after the idle loop has run for some length of time (e.g.,
1984 333 mS). On some machines, this will cause a hang at boot time or
1985 whenever the CPU becomes idle. (On machines with more than one CPU,
1986 this option does nothing.)
1988 config APM_DISPLAY_BLANK
1989 bool "Enable console blanking using APM"
1991 Enable console blanking using the APM. Some laptops can use this to
1992 turn off the LCD backlight when the screen blanker of the Linux
1993 virtual console blanks the screen. Note that this is only used by
1994 the virtual console screen blanker, and won't turn off the backlight
1995 when using the X Window system. This also doesn't have anything to
1996 do with your VESA-compliant power-saving monitor. Further, this
1997 option doesn't work for all laptops -- it might not turn off your
1998 backlight at all, or it might print a lot of errors to the console,
1999 especially if you are using gpm.
2001 config APM_ALLOW_INTS
2002 bool "Allow interrupts during APM BIOS calls"
2004 Normally we disable external interrupts while we are making calls to
2005 the APM BIOS as a measure to lessen the effects of a badly behaving
2006 BIOS implementation. The BIOS should reenable interrupts if it
2007 needs to. Unfortunately, some BIOSes do not -- especially those in
2008 many of the newer IBM Thinkpads. If you experience hangs when you
2009 suspend, try setting this to Y. Otherwise, say N.
2013 source "drivers/cpufreq/Kconfig"
2015 source "drivers/cpuidle/Kconfig"
2017 source "drivers/idle/Kconfig"
2022 menu "Bus options (PCI etc.)"
2027 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
2029 Find out whether you have a PCI motherboard. PCI is the name of a
2030 bus system, i.e. the way the CPU talks to the other stuff inside
2031 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2032 VESA. If you have PCI, say Y, otherwise N.
2035 prompt "PCI access mode"
2036 depends on X86_32 && PCI
2039 On PCI systems, the BIOS can be used to detect the PCI devices and
2040 determine their configuration. However, some old PCI motherboards
2041 have BIOS bugs and may crash if this is done. Also, some embedded
2042 PCI-based systems don't have any BIOS at all. Linux can also try to
2043 detect the PCI hardware directly without using the BIOS.
2045 With this option, you can specify how Linux should detect the
2046 PCI devices. If you choose "BIOS", the BIOS will be used,
2047 if you choose "Direct", the BIOS won't be used, and if you
2048 choose "MMConfig", then PCI Express MMCONFIG will be used.
2049 If you choose "Any", the kernel will try MMCONFIG, then the
2050 direct access method and falls back to the BIOS if that doesn't
2051 work. If unsure, go with the default, which is "Any".
2056 config PCI_GOMMCONFIG
2073 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2075 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2078 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2082 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2086 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2090 depends on PCI && XEN
2098 bool "Support mmconfig PCI config space access"
2099 depends on X86_64 && PCI && ACPI
2101 config PCI_CNB20LE_QUIRK
2102 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2105 Read the PCI windows out of the CNB20LE host bridge. This allows
2106 PCI hotplug to work on systems with the CNB20LE chipset which do
2109 There's no public spec for this chipset, and this functionality
2110 is known to be incomplete.
2112 You should say N unless you know you need this.
2114 source "drivers/pci/pcie/Kconfig"
2116 source "drivers/pci/Kconfig"
2118 # x86_64 have no ISA slots, but can have ISA-style DMA.
2120 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2123 Enables ISA-style DMA support for devices requiring such controllers.
2131 Find out whether you have ISA slots on your motherboard. ISA is the
2132 name of a bus system, i.e. the way the CPU talks to the other stuff
2133 inside your box. Other bus systems are PCI, EISA, MicroChannel
2134 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2135 newer boards don't support it. If you have ISA, say Y, otherwise N.
2141 The Extended Industry Standard Architecture (EISA) bus was
2142 developed as an open alternative to the IBM MicroChannel bus.
2144 The EISA bus provided some of the features of the IBM MicroChannel
2145 bus while maintaining backward compatibility with cards made for
2146 the older ISA bus. The EISA bus saw limited use between 1988 and
2147 1995 when it was made obsolete by the PCI bus.
2149 Say Y here if you are building a kernel for an EISA-based machine.
2153 source "drivers/eisa/Kconfig"
2156 tristate "NatSemi SCx200 support"
2158 This provides basic support for National Semiconductor's
2159 (now AMD's) Geode processors. The driver probes for the
2160 PCI-IDs of several on-chip devices, so its a good dependency
2161 for other scx200_* drivers.
2163 If compiled as a module, the driver is named scx200.
2165 config SCx200HR_TIMER
2166 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2170 This driver provides a clocksource built upon the on-chip
2171 27MHz high-resolution timer. Its also a workaround for
2172 NSC Geode SC-1100's buggy TSC, which loses time when the
2173 processor goes idle (as is done by the scheduler). The
2174 other workaround is idle=poll boot option.
2177 bool "One Laptop Per Child support"
2184 Add support for detecting the unique features of the OLPC
2188 bool "OLPC XO-1 Power Management"
2189 depends on OLPC && MFD_CS5535 && PM_SLEEP
2192 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2195 bool "OLPC XO-1 Real Time Clock"
2196 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2198 Add support for the XO-1 real time clock, which can be used as a
2199 programmable wakeup source.
2202 bool "OLPC XO-1 SCI extras"
2203 depends on OLPC && OLPC_XO1_PM
2209 Add support for SCI-based features of the OLPC XO-1 laptop:
2210 - EC-driven system wakeups
2214 - AC adapter status updates
2215 - Battery status updates
2217 config OLPC_XO15_SCI
2218 bool "OLPC XO-1.5 SCI extras"
2219 depends on OLPC && ACPI
2222 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2223 - EC-driven system wakeups
2224 - AC adapter status updates
2225 - Battery status updates
2228 bool "PCEngines ALIX System Support (LED setup)"
2231 This option enables system support for the PCEngines ALIX.
2232 At present this just sets up LEDs for GPIO control on
2233 ALIX2/3/6 boards. However, other system specific setup should
2236 Note: You must still enable the drivers for GPIO and LED support
2237 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2239 Note: You have to set alix.force=1 for boards with Award BIOS.
2242 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2245 This option enables system support for the Soekris Engineering net5501.
2248 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2252 This option enables system support for the Traverse Technologies GEOS.
2255 bool "Technologic Systems TS-5500 platform support"
2257 select CHECK_SIGNATURE
2261 This option enables system support for the Technologic Systems TS-5500.
2267 depends on CPU_SUP_AMD && PCI
2269 source "drivers/pcmcia/Kconfig"
2271 source "drivers/pci/hotplug/Kconfig"
2274 bool "RapidIO support"
2278 If you say Y here, the kernel will include drivers and
2279 infrastructure code to support RapidIO interconnect devices.
2281 source "drivers/rapidio/Kconfig"
2286 menu "Executable file formats / Emulations"
2288 source "fs/Kconfig.binfmt"
2290 config IA32_EMULATION
2291 bool "IA32 Emulation"
2294 select COMPAT_BINFMT_ELF
2297 Include code to run legacy 32-bit programs under a
2298 64-bit kernel. You should likely turn this on, unless you're
2299 100% sure that you don't have any 32-bit programs left.
2302 tristate "IA32 a.out support"
2303 depends on IA32_EMULATION
2305 Support old a.out binaries in the 32bit emulation.
2308 bool "x32 ABI for 64-bit mode"
2309 depends on X86_64 && IA32_EMULATION
2311 Include code to run binaries for the x32 native 32-bit ABI
2312 for 64-bit processors. An x32 process gets access to the
2313 full 64-bit register file and wide data path while leaving
2314 pointers at 32 bits for smaller memory footprint.
2316 You will need a recent binutils (2.22 or later) with
2317 elf32_x86_64 support enabled to compile a kernel with this
2322 depends on IA32_EMULATION || X86_X32
2323 select ARCH_WANT_OLD_COMPAT_IPC
2326 config COMPAT_FOR_U64_ALIGNMENT
2329 config SYSVIPC_COMPAT
2341 config HAVE_ATOMIC_IOMAP
2345 config HAVE_TEXT_POKE_SMP
2347 select STOP_MACHINE if SMP
2349 config X86_DEV_DMA_OPS
2351 depends on X86_64 || STA2X11
2353 config X86_DMA_REMAP
2357 source "net/Kconfig"
2359 source "drivers/Kconfig"
2361 source "drivers/firmware/Kconfig"
2365 source "arch/x86/Kconfig.debug"
2367 source "security/Kconfig"
2369 source "crypto/Kconfig"
2371 source "arch/x86/kvm/Kconfig"
2373 source "lib/Kconfig"
projects / firefly-linux-kernel-4.4.55.git / blob