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
125 config INSTRUCTION_DECODER
127 depends on KPROBES || PERF_EVENTS || UPROBES
131 default "elf32-i386" if X86_32
132 default "elf64-x86-64" if X86_64
134 config ARCH_DEFCONFIG
136 default "arch/x86/configs/i386_defconfig" if X86_32
137 default "arch/x86/configs/x86_64_defconfig" if X86_64
139 config LOCKDEP_SUPPORT
142 config STACKTRACE_SUPPORT
145 config HAVE_LATENCYTOP_SUPPORT
154 config NEED_DMA_MAP_STATE
156 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
158 config NEED_SG_DMA_LENGTH
161 config GENERIC_ISA_DMA
163 depends on ISA_DMA_API
168 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
170 config GENERIC_BUG_RELATIVE_POINTERS
173 config GENERIC_HWEIGHT
176 config ARCH_MAY_HAVE_PC_FDC
178 depends on ISA_DMA_API
180 config RWSEM_XCHGADD_ALGORITHM
183 config GENERIC_CALIBRATE_DELAY
186 config ARCH_HAS_CPU_RELAX
189 config ARCH_HAS_CACHE_LINE_SIZE
192 config ARCH_HAS_CPU_AUTOPROBE
195 config HAVE_SETUP_PER_CPU_AREA
198 config NEED_PER_CPU_EMBED_FIRST_CHUNK
201 config NEED_PER_CPU_PAGE_FIRST_CHUNK
204 config ARCH_HIBERNATION_POSSIBLE
207 config ARCH_SUSPEND_POSSIBLE
210 config ARCH_WANT_HUGE_PMD_SHARE
213 config ARCH_WANT_GENERAL_HUGETLB
224 config ARCH_SUPPORTS_OPTIMIZED_INLINING
227 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
230 config HAVE_INTEL_TXT
232 depends on INTEL_IOMMU && ACPI
236 depends on X86_32 && SMP
240 depends on X86_64 && SMP
246 config X86_32_LAZY_GS
248 depends on X86_32 && !CC_STACKPROTECTOR
250 config ARCH_HWEIGHT_CFLAGS
252 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
253 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
255 config ARCH_CPU_PROBE_RELEASE
257 depends on HOTPLUG_CPU
259 config ARCH_SUPPORTS_UPROBES
262 source "init/Kconfig"
263 source "kernel/Kconfig.freezer"
265 menu "Processor type and features"
268 bool "DMA memory allocation support" if EXPERT
271 DMA memory allocation support allows devices with less than 32-bit
272 addressing to allocate within the first 16MB of address space.
273 Disable if no such devices will be used.
278 bool "Symmetric multi-processing support"
280 This enables support for systems with more than one CPU. If you have
281 a system with only one CPU, like most personal computers, say N. If
282 you have a system with more than one CPU, say Y.
284 If you say N here, the kernel will run on single and multiprocessor
285 machines, but will use only one CPU of a multiprocessor machine. If
286 you say Y here, the kernel will run on many, but not all,
287 singleprocessor machines. On a singleprocessor machine, the kernel
288 will run faster if you say N here.
290 Note that if you say Y here and choose architecture "586" or
291 "Pentium" under "Processor family", the kernel will not work on 486
292 architectures. Similarly, multiprocessor kernels for the "PPro"
293 architecture may not work on all Pentium based boards.
295 People using multiprocessor machines who say Y here should also say
296 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
297 Management" code will be disabled if you say Y here.
299 See also <file:Documentation/x86/i386/IO-APIC.txt>,
300 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
301 <http://www.tldp.org/docs.html#howto>.
303 If you don't know what to do here, say N.
306 bool "Support x2apic"
307 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
309 This enables x2apic support on CPUs that have this feature.
311 This allows 32-bit apic IDs (so it can support very large systems),
312 and accesses the local apic via MSRs not via mmio.
314 If you don't know what to do here, say N.
317 bool "Enable MPS table" if ACPI || SFI
319 depends on X86_LOCAL_APIC
321 For old smp systems that do not have proper acpi support. Newer systems
322 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
325 bool "Support for big SMP systems with more than 8 CPUs"
326 depends on X86_32 && SMP
328 This option is needed for the systems that have more than 8 CPUs
332 depends on X86_GOLDFISH
335 config X86_EXTENDED_PLATFORM
336 bool "Support for extended (non-PC) x86 platforms"
339 If you disable this option then the kernel will only support
340 standard PC platforms. (which covers the vast majority of
343 If you enable this option then you'll be able to select support
344 for the following (non-PC) 32 bit x86 platforms:
345 Goldfish (Android emulator)
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)"
420 depends on X86_EXTENDED_PLATFORM
422 Enable support for the Goldfish virtual platform used primarily
423 for Android development. Unless you are building for the Android
424 Goldfish emulator say N here.
427 bool "CE4100 TV platform"
429 depends on PCI_GODIRECT
431 depends on X86_EXTENDED_PLATFORM
432 select X86_REBOOTFIXUPS
434 select OF_EARLY_FLATTREE
437 Select for the Intel CE media processor (CE4100) SOC.
438 This option compiles in support for the CE4100 SOC for settop
439 boxes and media devices.
441 config X86_WANT_INTEL_MID
442 bool "Intel MID platform support"
444 depends on X86_EXTENDED_PLATFORM
446 Select to build a kernel capable of supporting Intel MID platform
447 systems which do not have the PCI legacy interfaces (Moorestown,
448 Medfield). If you are building for a PC class system say N here.
450 if X86_WANT_INTEL_MID
456 bool "Medfield MID platform"
459 depends on X86_IO_APIC
467 select X86_PLATFORM_DEVICES
468 select MFD_INTEL_MSIC
470 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
471 Internet Device(MID) platform.
472 Unlike standard x86 PCs, Medfield does not have many legacy devices
473 nor standard legacy replacement devices/features. e.g. Medfield does
474 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
478 config X86_INTEL_LPSS
479 bool "Intel Low Power Subsystem Support"
483 Select to build support for Intel Low Power Subsystem such as
484 found on Intel Lynxpoint PCH. Selecting this option enables
485 things like clock tree (common clock framework) which are needed
486 by the LPSS peripheral drivers.
489 bool "RDC R-321x SoC"
491 depends on X86_EXTENDED_PLATFORM
493 select X86_REBOOTFIXUPS
495 This option is needed for RDC R-321x system-on-chip, also known
497 If you don't have one of these chips, you should say N here.
499 config X86_32_NON_STANDARD
500 bool "Support non-standard 32-bit SMP architectures"
501 depends on X86_32 && SMP
502 depends on X86_EXTENDED_PLATFORM
504 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
505 STA2X11, default subarchitectures. It is intended for a generic
506 binary kernel. If you select them all, kernel will probe it
507 one by one and will fallback to default.
509 # Alphabetically sorted list of Non standard 32 bit platforms
512 bool "NUMAQ (IBM/Sequent)"
513 depends on X86_32_NON_STANDARD
518 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
519 NUMA multiquad box. This changes the way that processors are
520 bootstrapped, and uses Clustered Logical APIC addressing mode instead
521 of Flat Logical. You will need a new lynxer.elf file to flash your
522 firmware with - send email to <Martin.Bligh@us.ibm.com>.
524 config X86_SUPPORTS_MEMORY_FAILURE
526 # MCE code calls memory_failure():
528 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
529 depends on !X86_NUMAQ
530 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
531 depends on X86_64 || !SPARSEMEM
532 select ARCH_SUPPORTS_MEMORY_FAILURE
535 bool "SGI 320/540 (Visual Workstation)"
536 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
537 depends on X86_32_NON_STANDARD
539 The SGI Visual Workstation series is an IA32-based workstation
540 based on SGI systems chips with some legacy PC hardware attached.
542 Say Y here to create a kernel to run on the SGI 320 or 540.
544 A kernel compiled for the Visual Workstation will run on general
545 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
548 bool "STA2X11 Companion Chip Support"
549 depends on X86_32_NON_STANDARD && PCI
550 select X86_DEV_DMA_OPS
554 select ARCH_REQUIRE_GPIOLIB
557 This adds support for boards based on the STA2X11 IO-Hub,
558 a.k.a. "ConneXt". The chip is used in place of the standard
559 PC chipset, so all "standard" peripherals are missing. If this
560 option is selected the kernel will still be able to boot on
561 standard PC machines.
564 bool "Summit/EXA (IBM x440)"
565 depends on X86_32_NON_STANDARD
567 This option is needed for IBM systems that use the Summit/EXA chipset.
568 In particular, it is needed for the x440.
571 bool "Unisys ES7000 IA32 series"
572 depends on X86_32_NON_STANDARD && X86_BIGSMP
574 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
575 supposed to run on an IA32-based Unisys ES7000 system.
578 tristate "Eurobraille/Iris poweroff module"
581 The Iris machines from EuroBraille do not have APM or ACPI support
582 to shut themselves down properly. A special I/O sequence is
583 needed to do so, which is what this module does at
586 This is only for Iris machines from EuroBraille.
590 config SCHED_OMIT_FRAME_POINTER
592 prompt "Single-depth WCHAN output"
595 Calculate simpler /proc/<PID>/wchan values. If this option
596 is disabled then wchan values will recurse back to the
597 caller function. This provides more accurate wchan values,
598 at the expense of slightly more scheduling overhead.
600 If in doubt, say "Y".
602 menuconfig HYPERVISOR_GUEST
603 bool "Linux guest support"
605 Say Y here to enable options for running Linux under various hyper-
606 visors. This option enables basic hypervisor detection and platform
609 If you say N, all options in this submenu will be skipped and
610 disabled, and Linux guest support won't be built in.
615 bool "Enable paravirtualization code"
617 This changes the kernel so it can modify itself when it is run
618 under a hypervisor, potentially improving performance significantly
619 over full virtualization. However, when run without a hypervisor
620 the kernel is theoretically slower and slightly larger.
622 config PARAVIRT_DEBUG
623 bool "paravirt-ops debugging"
624 depends on PARAVIRT && DEBUG_KERNEL
626 Enable to debug paravirt_ops internals. Specifically, BUG if
627 a paravirt_op is missing when it is called.
629 config PARAVIRT_SPINLOCKS
630 bool "Paravirtualization layer for spinlocks"
631 depends on PARAVIRT && SMP
633 Paravirtualized spinlocks allow a pvops backend to replace the
634 spinlock implementation with something virtualization-friendly
635 (for example, block the virtual CPU rather than spinning).
637 Unfortunately the downside is an up to 5% performance hit on
638 native kernels, with various workloads.
640 If you are unsure how to answer this question, answer N.
642 source "arch/x86/xen/Kconfig"
645 bool "KVM Guest support (including kvmclock)"
647 select PARAVIRT_CLOCK
650 This option enables various optimizations for running under the KVM
651 hypervisor. It includes a paravirtualized clock, so that instead
652 of relying on a PIT (or probably other) emulation by the
653 underlying device model, the host provides the guest with
654 timing infrastructure such as time of day, and system time
656 source "arch/x86/lguest/Kconfig"
658 config PARAVIRT_TIME_ACCOUNTING
659 bool "Paravirtual steal time accounting"
663 Select this option to enable fine granularity task steal time
664 accounting. Time spent executing other tasks in parallel with
665 the current vCPU is discounted from the vCPU power. To account for
666 that, there can be a small performance impact.
668 If in doubt, say N here.
670 config PARAVIRT_CLOCK
673 endif #HYPERVISOR_GUEST
681 This option adds a kernel parameter 'memtest', which allows memtest
683 memtest=0, mean disabled; -- default
684 memtest=1, mean do 1 test pattern;
686 memtest=4, mean do 4 test patterns.
687 If you are unsure how to answer this question, answer N.
689 config X86_SUMMIT_NUMA
691 depends on X86_32 && NUMA && X86_32_NON_STANDARD
693 config X86_CYCLONE_TIMER
695 depends on X86_SUMMIT
697 source "arch/x86/Kconfig.cpu"
701 prompt "HPET Timer Support" if X86_32
703 Use the IA-PC HPET (High Precision Event Timer) to manage
704 time in preference to the PIT and RTC, if a HPET is
706 HPET is the next generation timer replacing legacy 8254s.
707 The HPET provides a stable time base on SMP
708 systems, unlike the TSC, but it is more expensive to access,
709 as it is off-chip. You can find the HPET spec at
710 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
712 You can safely choose Y here. However, HPET will only be
713 activated if the platform and the BIOS support this feature.
714 Otherwise the 8254 will be used for timing services.
716 Choose N to continue using the legacy 8254 timer.
718 config HPET_EMULATE_RTC
720 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
723 def_bool y if X86_INTEL_MID
724 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
726 depends on X86_INTEL_MID && SFI
728 APB timer is the replacement for 8254, HPET on X86 MID platforms.
729 The APBT provides a stable time base on SMP
730 systems, unlike the TSC, but it is more expensive to access,
731 as it is off-chip. APB timers are always running regardless of CPU
732 C states, they are used as per CPU clockevent device when possible.
734 # Mark as expert because too many people got it wrong.
735 # The code disables itself when not needed.
738 bool "Enable DMI scanning" if EXPERT
740 Enabled scanning of DMI to identify machine quirks. Say Y
741 here unless you have verified that your setup is not
742 affected by entries in the DMI blacklist. Required by PNP
746 bool "GART IOMMU support" if EXPERT
749 depends on X86_64 && PCI && AMD_NB
751 Support for full DMA access of devices with 32bit memory access only
752 on systems with more than 3GB. This is usually needed for USB,
753 sound, many IDE/SATA chipsets and some other devices.
754 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
755 based hardware IOMMU and a software bounce buffer based IOMMU used
756 on Intel systems and as fallback.
757 The code is only active when needed (enough memory and limited
758 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
762 bool "IBM Calgary IOMMU support"
764 depends on X86_64 && PCI
766 Support for hardware IOMMUs in IBM's xSeries x366 and x460
767 systems. Needed to run systems with more than 3GB of memory
768 properly with 32-bit PCI devices that do not support DAC
769 (Double Address Cycle). Calgary also supports bus level
770 isolation, where all DMAs pass through the IOMMU. This
771 prevents them from going anywhere except their intended
772 destination. This catches hard-to-find kernel bugs and
773 mis-behaving drivers and devices that do not use the DMA-API
774 properly to set up their DMA buffers. The IOMMU can be
775 turned off at boot time with the iommu=off parameter.
776 Normally the kernel will make the right choice by itself.
779 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
781 prompt "Should Calgary be enabled by default?"
782 depends on CALGARY_IOMMU
784 Should Calgary be enabled by default? if you choose 'y', Calgary
785 will be used (if it exists). If you choose 'n', Calgary will not be
786 used even if it exists. If you choose 'n' and would like to use
787 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
790 # need this always selected by IOMMU for the VIA workaround
794 Support for software bounce buffers used on x86-64 systems
795 which don't have a hardware IOMMU. Using this PCI devices
796 which can only access 32-bits of memory can be used on systems
797 with more than 3 GB of memory.
802 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
805 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
806 depends on X86_64 && SMP && DEBUG_KERNEL
807 select CPUMASK_OFFSTACK
809 Enable maximum number of CPUS and NUMA Nodes for this architecture.
813 int "Maximum number of CPUs" if SMP && !MAXSMP
814 range 2 8 if SMP && X86_32 && !X86_BIGSMP
815 range 2 512 if SMP && !MAXSMP
817 default "4096" if MAXSMP
818 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
821 This allows you to specify the maximum number of CPUs which this
822 kernel will support. The maximum supported value is 512 and the
823 minimum value which makes sense is 2.
825 This is purely to save memory - each supported CPU adds
826 approximately eight kilobytes to the kernel image.
829 bool "SMT (Hyperthreading) scheduler support"
832 SMT scheduler support improves the CPU scheduler's decision making
833 when dealing with Intel Pentium 4 chips with HyperThreading at a
834 cost of slightly increased overhead in some places. If unsure say
839 prompt "Multi-core scheduler support"
842 Multi-core scheduler support improves the CPU scheduler's decision
843 making when dealing with multi-core CPU chips at a cost of slightly
844 increased overhead in some places. If unsure say N here.
846 source "kernel/Kconfig.preempt"
849 bool "Local APIC support on uniprocessors"
850 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
852 A local APIC (Advanced Programmable Interrupt Controller) is an
853 integrated interrupt controller in the CPU. If you have a single-CPU
854 system which has a processor with a local APIC, you can say Y here to
855 enable and use it. If you say Y here even though your machine doesn't
856 have a local APIC, then the kernel will still run with no slowdown at
857 all. The local APIC supports CPU-generated self-interrupts (timer,
858 performance counters), and the NMI watchdog which detects hard
862 bool "IO-APIC support on uniprocessors"
863 depends on X86_UP_APIC
865 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
866 SMP-capable replacement for PC-style interrupt controllers. Most
867 SMP systems and many recent uniprocessor systems have one.
869 If you have a single-CPU system with an IO-APIC, you can say Y here
870 to use it. If you say Y here even though your machine doesn't have
871 an IO-APIC, then the kernel will still run with no slowdown at all.
873 config X86_LOCAL_APIC
875 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
879 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
881 config X86_VISWS_APIC
883 depends on X86_32 && X86_VISWS
885 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
886 bool "Reroute for broken boot IRQs"
887 depends on X86_IO_APIC
889 This option enables a workaround that fixes a source of
890 spurious interrupts. This is recommended when threaded
891 interrupt handling is used on systems where the generation of
892 superfluous "boot interrupts" cannot be disabled.
894 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
895 entry in the chipset's IO-APIC is masked (as, e.g. the RT
896 kernel does during interrupt handling). On chipsets where this
897 boot IRQ generation cannot be disabled, this workaround keeps
898 the original IRQ line masked so that only the equivalent "boot
899 IRQ" is delivered to the CPUs. The workaround also tells the
900 kernel to set up the IRQ handler on the boot IRQ line. In this
901 way only one interrupt is delivered to the kernel. Otherwise
902 the spurious second interrupt may cause the kernel to bring
903 down (vital) interrupt lines.
905 Only affects "broken" chipsets. Interrupt sharing may be
906 increased on these systems.
909 bool "Machine Check / overheating reporting"
912 Machine Check support allows the processor to notify the
913 kernel if it detects a problem (e.g. overheating, data corruption).
914 The action the kernel takes depends on the severity of the problem,
915 ranging from warning messages to halting the machine.
919 prompt "Intel MCE features"
920 depends on X86_MCE && X86_LOCAL_APIC
922 Additional support for intel specific MCE features such as
927 prompt "AMD MCE features"
928 depends on X86_MCE && X86_LOCAL_APIC
930 Additional support for AMD specific MCE features such as
931 the DRAM Error Threshold.
933 config X86_ANCIENT_MCE
934 bool "Support for old Pentium 5 / WinChip machine checks"
935 depends on X86_32 && X86_MCE
937 Include support for machine check handling on old Pentium 5 or WinChip
938 systems. These typically need to be enabled explicitely on the command
941 config X86_MCE_THRESHOLD
942 depends on X86_MCE_AMD || X86_MCE_INTEL
945 config X86_MCE_INJECT
947 tristate "Machine check injector support"
949 Provide support for injecting machine checks for testing purposes.
950 If you don't know what a machine check is and you don't do kernel
951 QA it is safe to say n.
953 config X86_THERMAL_VECTOR
955 depends on X86_MCE_INTEL
958 bool "Enable VM86 support" if EXPERT
962 This option is required by programs like DOSEMU to run 16-bit legacy
963 code on X86 processors. It also may be needed by software like
964 XFree86 to initialize some video cards via BIOS. Disabling this
965 option saves about 6k.
968 tristate "Toshiba Laptop support"
971 This adds a driver to safely access the System Management Mode of
972 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
973 not work on models with a Phoenix BIOS. The System Management Mode
974 is used to set the BIOS and power saving options on Toshiba portables.
976 For information on utilities to make use of this driver see the
977 Toshiba Linux utilities web site at:
978 <http://www.buzzard.org.uk/toshiba/>.
980 Say Y if you intend to run this kernel on a Toshiba portable.
984 tristate "Dell laptop support"
987 This adds a driver to safely access the System Management Mode
988 of the CPU on the Dell Inspiron 8000. The System Management Mode
989 is used to read cpu temperature and cooling fan status and to
990 control the fans on the I8K portables.
992 This driver has been tested only on the Inspiron 8000 but it may
993 also work with other Dell laptops. You can force loading on other
994 models by passing the parameter `force=1' to the module. Use at
997 For information on utilities to make use of this driver see the
998 I8K Linux utilities web site at:
999 <http://people.debian.org/~dz/i8k/>
1001 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1004 config X86_REBOOTFIXUPS
1005 bool "Enable X86 board specific fixups for reboot"
1008 This enables chipset and/or board specific fixups to be done
1009 in order to get reboot to work correctly. This is only needed on
1010 some combinations of hardware and BIOS. The symptom, for which
1011 this config is intended, is when reboot ends with a stalled/hung
1014 Currently, the only fixup is for the Geode machines using
1015 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1017 Say Y if you want to enable the fixup. Currently, it's safe to
1018 enable this option even if you don't need it.
1022 tristate "CPU microcode loading support"
1026 If you say Y here, you will be able to update the microcode on
1027 certain Intel and AMD processors. The Intel support is for the
1028 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1029 Xeon etc. The AMD support is for families 0x10 and later. You will
1030 obviously need the actual microcode binary data itself which is not
1031 shipped with the Linux kernel.
1033 This option selects the general module only, you need to select
1034 at least one vendor specific module as well.
1036 To compile this driver as a module, choose M here: the module
1037 will be called microcode.
1039 config MICROCODE_INTEL
1040 bool "Intel microcode loading support"
1041 depends on MICROCODE
1045 This options enables microcode patch loading support for Intel
1048 For latest news and information on obtaining all the required
1049 Intel ingredients for this driver, check:
1050 <http://www.urbanmyth.org/microcode/>.
1052 config MICROCODE_AMD
1053 bool "AMD microcode loading support"
1054 depends on MICROCODE
1057 If you select this option, microcode patch loading support for AMD
1058 processors will be enabled.
1060 config MICROCODE_OLD_INTERFACE
1062 depends on MICROCODE
1064 config MICROCODE_INTEL_LIB
1066 depends on MICROCODE_INTEL
1068 config MICROCODE_INTEL_EARLY
1071 config MICROCODE_AMD_EARLY
1074 config MICROCODE_EARLY
1075 bool "Early load microcode"
1076 depends on MICROCODE=y && BLK_DEV_INITRD
1077 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1078 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1081 This option provides functionality to read additional microcode data
1082 at the beginning of initrd image. The data tells kernel to load
1083 microcode to CPU's as early as possible. No functional change if no
1084 microcode data is glued to the initrd, therefore it's safe to say Y.
1087 tristate "/dev/cpu/*/msr - Model-specific register support"
1089 This device gives privileged processes access to the x86
1090 Model-Specific Registers (MSRs). It is a character device with
1091 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1092 MSR accesses are directed to a specific CPU on multi-processor
1096 tristate "/dev/cpu/*/cpuid - CPU information support"
1098 This device gives processes access to the x86 CPUID instruction to
1099 be executed on a specific processor. It is a character device
1100 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1104 prompt "High Memory Support"
1105 default HIGHMEM64G if X86_NUMAQ
1111 depends on !X86_NUMAQ
1113 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1114 However, the address space of 32-bit x86 processors is only 4
1115 Gigabytes large. That means that, if you have a large amount of
1116 physical memory, not all of it can be "permanently mapped" by the
1117 kernel. The physical memory that's not permanently mapped is called
1120 If you are compiling a kernel which will never run on a machine with
1121 more than 1 Gigabyte total physical RAM, answer "off" here (default
1122 choice and suitable for most users). This will result in a "3GB/1GB"
1123 split: 3GB are mapped so that each process sees a 3GB virtual memory
1124 space and the remaining part of the 4GB virtual memory space is used
1125 by the kernel to permanently map as much physical memory as
1128 If the machine has between 1 and 4 Gigabytes physical RAM, then
1131 If more than 4 Gigabytes is used then answer "64GB" here. This
1132 selection turns Intel PAE (Physical Address Extension) mode on.
1133 PAE implements 3-level paging on IA32 processors. PAE is fully
1134 supported by Linux, PAE mode is implemented on all recent Intel
1135 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1136 then the kernel will not boot on CPUs that don't support PAE!
1138 The actual amount of total physical memory will either be
1139 auto detected or can be forced by using a kernel command line option
1140 such as "mem=256M". (Try "man bootparam" or see the documentation of
1141 your boot loader (lilo or loadlin) about how to pass options to the
1142 kernel at boot time.)
1144 If unsure, say "off".
1148 depends on !X86_NUMAQ
1150 Select this if you have a 32-bit processor and between 1 and 4
1151 gigabytes of physical RAM.
1158 Select this if you have a 32-bit processor and more than 4
1159 gigabytes of physical RAM.
1164 prompt "Memory split" if EXPERT
1168 Select the desired split between kernel and user memory.
1170 If the address range available to the kernel is less than the
1171 physical memory installed, the remaining memory will be available
1172 as "high memory". Accessing high memory is a little more costly
1173 than low memory, as it needs to be mapped into the kernel first.
1174 Note that increasing the kernel address space limits the range
1175 available to user programs, making the address space there
1176 tighter. Selecting anything other than the default 3G/1G split
1177 will also likely make your kernel incompatible with binary-only
1180 If you are not absolutely sure what you are doing, leave this
1184 bool "3G/1G user/kernel split"
1185 config VMSPLIT_3G_OPT
1187 bool "3G/1G user/kernel split (for full 1G low memory)"
1189 bool "2G/2G user/kernel split"
1190 config VMSPLIT_2G_OPT
1192 bool "2G/2G user/kernel split (for full 2G low memory)"
1194 bool "1G/3G user/kernel split"
1199 default 0xB0000000 if VMSPLIT_3G_OPT
1200 default 0x80000000 if VMSPLIT_2G
1201 default 0x78000000 if VMSPLIT_2G_OPT
1202 default 0x40000000 if VMSPLIT_1G
1208 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1211 bool "PAE (Physical Address Extension) Support"
1212 depends on X86_32 && !HIGHMEM4G
1214 PAE is required for NX support, and furthermore enables
1215 larger swapspace support for non-overcommit purposes. It
1216 has the cost of more pagetable lookup overhead, and also
1217 consumes more pagetable space per process.
1219 config ARCH_PHYS_ADDR_T_64BIT
1221 depends on X86_64 || X86_PAE
1223 config ARCH_DMA_ADDR_T_64BIT
1225 depends on X86_64 || HIGHMEM64G
1227 config DIRECT_GBPAGES
1228 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1232 Allow the kernel linear mapping to use 1GB pages on CPUs that
1233 support it. This can improve the kernel's performance a tiny bit by
1234 reducing TLB pressure. If in doubt, say "Y".
1236 # Common NUMA Features
1238 bool "Numa Memory Allocation and Scheduler Support"
1240 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI))
1241 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1243 Enable NUMA (Non Uniform Memory Access) support.
1245 The kernel will try to allocate memory used by a CPU on the
1246 local memory controller of the CPU and add some more
1247 NUMA awareness to the kernel.
1249 For 64-bit this is recommended if the system is Intel Core i7
1250 (or later), AMD Opteron, or EM64T NUMA.
1252 For 32-bit this is only needed on (rare) 32-bit-only platforms
1253 that support NUMA topologies, such as NUMAQ / Summit, or if you
1254 boot a 32-bit kernel on a 64-bit NUMA platform.
1256 Otherwise, you should say N.
1258 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1259 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1263 prompt "Old style AMD Opteron NUMA detection"
1264 depends on X86_64 && NUMA && PCI
1266 Enable AMD NUMA node topology detection. You should say Y here if
1267 you have a multi processor AMD system. This uses an old method to
1268 read the NUMA configuration directly from the builtin Northbridge
1269 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1270 which also takes priority if both are compiled in.
1272 config X86_64_ACPI_NUMA
1274 prompt "ACPI NUMA detection"
1275 depends on X86_64 && NUMA && ACPI && PCI
1278 Enable ACPI SRAT based node topology detection.
1280 # Some NUMA nodes have memory ranges that span
1281 # other nodes. Even though a pfn is valid and
1282 # between a node's start and end pfns, it may not
1283 # reside on that node. See memmap_init_zone()
1285 config NODES_SPAN_OTHER_NODES
1287 depends on X86_64_ACPI_NUMA
1290 bool "NUMA emulation"
1293 Enable NUMA emulation. A flat machine will be split
1294 into virtual nodes when booted with "numa=fake=N", where N is the
1295 number of nodes. This is only useful for debugging.
1298 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1300 default "10" if MAXSMP
1301 default "6" if X86_64
1302 default "4" if X86_NUMAQ
1304 depends on NEED_MULTIPLE_NODES
1306 Specify the maximum number of NUMA Nodes available on the target
1307 system. Increases memory reserved to accommodate various tables.
1309 config ARCH_HAVE_MEMORY_PRESENT
1311 depends on X86_32 && DISCONTIGMEM
1313 config NEED_NODE_MEMMAP_SIZE
1315 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1317 config ARCH_FLATMEM_ENABLE
1319 depends on X86_32 && !NUMA
1321 config ARCH_DISCONTIGMEM_ENABLE
1323 depends on NUMA && X86_32
1325 config ARCH_DISCONTIGMEM_DEFAULT
1327 depends on NUMA && X86_32
1329 config ARCH_SPARSEMEM_ENABLE
1331 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1332 select SPARSEMEM_STATIC if X86_32
1333 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1335 config ARCH_SPARSEMEM_DEFAULT
1339 config ARCH_SELECT_MEMORY_MODEL
1341 depends on ARCH_SPARSEMEM_ENABLE
1343 config ARCH_MEMORY_PROBE
1345 depends on X86_64 && MEMORY_HOTPLUG
1347 config ARCH_PROC_KCORE_TEXT
1349 depends on X86_64 && PROC_KCORE
1351 config ILLEGAL_POINTER_VALUE
1354 default 0xdead000000000000 if X86_64
1359 bool "Allocate 3rd-level pagetables from highmem"
1362 The VM uses one page table entry for each page of physical memory.
1363 For systems with a lot of RAM, this can be wasteful of precious
1364 low memory. Setting this option will put user-space page table
1365 entries in high memory.
1367 config X86_CHECK_BIOS_CORRUPTION
1368 bool "Check for low memory corruption"
1370 Periodically check for memory corruption in low memory, which
1371 is suspected to be caused by BIOS. Even when enabled in the
1372 configuration, it is disabled at runtime. Enable it by
1373 setting "memory_corruption_check=1" on the kernel command
1374 line. By default it scans the low 64k of memory every 60
1375 seconds; see the memory_corruption_check_size and
1376 memory_corruption_check_period parameters in
1377 Documentation/kernel-parameters.txt to adjust this.
1379 When enabled with the default parameters, this option has
1380 almost no overhead, as it reserves a relatively small amount
1381 of memory and scans it infrequently. It both detects corruption
1382 and prevents it from affecting the running system.
1384 It is, however, intended as a diagnostic tool; if repeatable
1385 BIOS-originated corruption always affects the same memory,
1386 you can use memmap= to prevent the kernel from using that
1389 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1390 bool "Set the default setting of memory_corruption_check"
1391 depends on X86_CHECK_BIOS_CORRUPTION
1394 Set whether the default state of memory_corruption_check is
1397 config X86_RESERVE_LOW
1398 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1402 Specify the amount of low memory to reserve for the BIOS.
1404 The first page contains BIOS data structures that the kernel
1405 must not use, so that page must always be reserved.
1407 By default we reserve the first 64K of physical RAM, as a
1408 number of BIOSes are known to corrupt that memory range
1409 during events such as suspend/resume or monitor cable
1410 insertion, so it must not be used by the kernel.
1412 You can set this to 4 if you are absolutely sure that you
1413 trust the BIOS to get all its memory reservations and usages
1414 right. If you know your BIOS have problems beyond the
1415 default 64K area, you can set this to 640 to avoid using the
1416 entire low memory range.
1418 If you have doubts about the BIOS (e.g. suspend/resume does
1419 not work or there's kernel crashes after certain hardware
1420 hotplug events) then you might want to enable
1421 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1422 typical corruption patterns.
1424 Leave this to the default value of 64 if you are unsure.
1426 config MATH_EMULATION
1428 prompt "Math emulation" if X86_32
1430 Linux can emulate a math coprocessor (used for floating point
1431 operations) if you don't have one. 486DX and Pentium processors have
1432 a math coprocessor built in, 486SX and 386 do not, unless you added
1433 a 487DX or 387, respectively. (The messages during boot time can
1434 give you some hints here ["man dmesg"].) Everyone needs either a
1435 coprocessor or this emulation.
1437 If you don't have a math coprocessor, you need to say Y here; if you
1438 say Y here even though you have a coprocessor, the coprocessor will
1439 be used nevertheless. (This behavior can be changed with the kernel
1440 command line option "no387", which comes handy if your coprocessor
1441 is broken. Try "man bootparam" or see the documentation of your boot
1442 loader (lilo or loadlin) about how to pass options to the kernel at
1443 boot time.) This means that it is a good idea to say Y here if you
1444 intend to use this kernel on different machines.
1446 More information about the internals of the Linux math coprocessor
1447 emulation can be found in <file:arch/x86/math-emu/README>.
1449 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1450 kernel, it won't hurt.
1454 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1456 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1457 the Memory Type Range Registers (MTRRs) may be used to control
1458 processor access to memory ranges. This is most useful if you have
1459 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1460 allows bus write transfers to be combined into a larger transfer
1461 before bursting over the PCI/AGP bus. This can increase performance
1462 of image write operations 2.5 times or more. Saying Y here creates a
1463 /proc/mtrr file which may be used to manipulate your processor's
1464 MTRRs. Typically the X server should use this.
1466 This code has a reasonably generic interface so that similar
1467 control registers on other processors can be easily supported
1470 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1471 Registers (ARRs) which provide a similar functionality to MTRRs. For
1472 these, the ARRs are used to emulate the MTRRs.
1473 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1474 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1475 write-combining. All of these processors are supported by this code
1476 and it makes sense to say Y here if you have one of them.
1478 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1479 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1480 can lead to all sorts of problems, so it's good to say Y here.
1482 You can safely say Y even if your machine doesn't have MTRRs, you'll
1483 just add about 9 KB to your kernel.
1485 See <file:Documentation/x86/mtrr.txt> for more information.
1487 config MTRR_SANITIZER
1489 prompt "MTRR cleanup support"
1492 Convert MTRR layout from continuous to discrete, so X drivers can
1493 add writeback entries.
1495 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1496 The largest mtrr entry size for a continuous block can be set with
1501 config MTRR_SANITIZER_ENABLE_DEFAULT
1502 int "MTRR cleanup enable value (0-1)"
1505 depends on MTRR_SANITIZER
1507 Enable mtrr cleanup default value
1509 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1510 int "MTRR cleanup spare reg num (0-7)"
1513 depends on MTRR_SANITIZER
1515 mtrr cleanup spare entries default, it can be changed via
1516 mtrr_spare_reg_nr=N on the kernel command line.
1520 prompt "x86 PAT support" if EXPERT
1523 Use PAT attributes to setup page level cache control.
1525 PATs are the modern equivalents of MTRRs and are much more
1526 flexible than MTRRs.
1528 Say N here if you see bootup problems (boot crash, boot hang,
1529 spontaneous reboots) or a non-working video driver.
1533 config ARCH_USES_PG_UNCACHED
1539 prompt "x86 architectural random number generator" if EXPERT
1541 Enable the x86 architectural RDRAND instruction
1542 (Intel Bull Mountain technology) to generate random numbers.
1543 If supported, this is a high bandwidth, cryptographically
1544 secure hardware random number generator.
1548 prompt "Supervisor Mode Access Prevention" if EXPERT
1550 Supervisor Mode Access Prevention (SMAP) is a security
1551 feature in newer Intel processors. There is a small
1552 performance cost if this enabled and turned on; there is
1553 also a small increase in the kernel size if this is enabled.
1558 bool "EFI runtime service support"
1562 This enables the kernel to use EFI runtime services that are
1563 available (such as the EFI variable services).
1565 This option is only useful on systems that have EFI firmware.
1566 In addition, you should use the latest ELILO loader available
1567 at <http://elilo.sourceforge.net> in order to take advantage
1568 of EFI runtime services. However, even with this option, the
1569 resultant kernel should continue to boot on existing non-EFI
1573 bool "EFI stub support"
1576 This kernel feature allows a bzImage to be loaded directly
1577 by EFI firmware without the use of a bootloader.
1579 See Documentation/x86/efi-stub.txt for more information.
1583 prompt "Enable seccomp to safely compute untrusted bytecode"
1585 This kernel feature is useful for number crunching applications
1586 that may need to compute untrusted bytecode during their
1587 execution. By using pipes or other transports made available to
1588 the process as file descriptors supporting the read/write
1589 syscalls, it's possible to isolate those applications in
1590 their own address space using seccomp. Once seccomp is
1591 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1592 and the task is only allowed to execute a few safe syscalls
1593 defined by each seccomp mode.
1595 If unsure, say Y. Only embedded should say N here.
1597 config CC_STACKPROTECTOR
1598 bool "Enable -fstack-protector buffer overflow detection"
1600 This option turns on the -fstack-protector GCC feature. This
1601 feature puts, at the beginning of functions, a canary value on
1602 the stack just before the return address, and validates
1603 the value just before actually returning. Stack based buffer
1604 overflows (that need to overwrite this return address) now also
1605 overwrite the canary, which gets detected and the attack is then
1606 neutralized via a kernel panic.
1608 This feature requires gcc version 4.2 or above, or a distribution
1609 gcc with the feature backported. Older versions are automatically
1610 detected and for those versions, this configuration option is
1611 ignored. (and a warning is printed during bootup)
1613 source kernel/Kconfig.hz
1616 bool "kexec system call"
1618 kexec is a system call that implements the ability to shutdown your
1619 current kernel, and to start another kernel. It is like a reboot
1620 but it is independent of the system firmware. And like a reboot
1621 you can start any kernel with it, not just Linux.
1623 The name comes from the similarity to the exec system call.
1625 It is an ongoing process to be certain the hardware in a machine
1626 is properly shutdown, so do not be surprised if this code does not
1627 initially work for you. It may help to enable device hotplugging
1628 support. As of this writing the exact hardware interface is
1629 strongly in flux, so no good recommendation can be made.
1632 bool "kernel crash dumps"
1633 depends on X86_64 || (X86_32 && HIGHMEM)
1635 Generate crash dump after being started by kexec.
1636 This should be normally only set in special crash dump kernels
1637 which are loaded in the main kernel with kexec-tools into
1638 a specially reserved region and then later executed after
1639 a crash by kdump/kexec. The crash dump kernel must be compiled
1640 to a memory address not used by the main kernel or BIOS using
1641 PHYSICAL_START, or it must be built as a relocatable image
1642 (CONFIG_RELOCATABLE=y).
1643 For more details see Documentation/kdump/kdump.txt
1647 depends on KEXEC && HIBERNATION
1649 Jump between original kernel and kexeced kernel and invoke
1650 code in physical address mode via KEXEC
1652 config PHYSICAL_START
1653 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1656 This gives the physical address where the kernel is loaded.
1658 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1659 bzImage will decompress itself to above physical address and
1660 run from there. Otherwise, bzImage will run from the address where
1661 it has been loaded by the boot loader and will ignore above physical
1664 In normal kdump cases one does not have to set/change this option
1665 as now bzImage can be compiled as a completely relocatable image
1666 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1667 address. This option is mainly useful for the folks who don't want
1668 to use a bzImage for capturing the crash dump and want to use a
1669 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1670 to be specifically compiled to run from a specific memory area
1671 (normally a reserved region) and this option comes handy.
1673 So if you are using bzImage for capturing the crash dump,
1674 leave the value here unchanged to 0x1000000 and set
1675 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1676 for capturing the crash dump change this value to start of
1677 the reserved region. In other words, it can be set based on
1678 the "X" value as specified in the "crashkernel=YM@XM"
1679 command line boot parameter passed to the panic-ed
1680 kernel. Please take a look at Documentation/kdump/kdump.txt
1681 for more details about crash dumps.
1683 Usage of bzImage for capturing the crash dump is recommended as
1684 one does not have to build two kernels. Same kernel can be used
1685 as production kernel and capture kernel. Above option should have
1686 gone away after relocatable bzImage support is introduced. But it
1687 is present because there are users out there who continue to use
1688 vmlinux for dump capture. This option should go away down the
1691 Don't change this unless you know what you are doing.
1694 bool "Build a relocatable kernel"
1697 This builds a kernel image that retains relocation information
1698 so it can be loaded someplace besides the default 1MB.
1699 The relocations tend to make the kernel binary about 10% larger,
1700 but are discarded at runtime.
1702 One use is for the kexec on panic case where the recovery kernel
1703 must live at a different physical address than the primary
1706 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1707 it has been loaded at and the compile time physical address
1708 (CONFIG_PHYSICAL_START) is ignored.
1710 # Relocation on x86-32 needs some additional build support
1711 config X86_NEED_RELOCS
1713 depends on X86_32 && RELOCATABLE
1715 config PHYSICAL_ALIGN
1716 hex "Alignment value to which kernel should be aligned" if X86_32
1718 range 0x2000 0x1000000
1720 This value puts the alignment restrictions on physical address
1721 where kernel is loaded and run from. Kernel is compiled for an
1722 address which meets above alignment restriction.
1724 If bootloader loads the kernel at a non-aligned address and
1725 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1726 address aligned to above value and run from there.
1728 If bootloader loads the kernel at a non-aligned address and
1729 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1730 load address and decompress itself to the address it has been
1731 compiled for and run from there. The address for which kernel is
1732 compiled already meets above alignment restrictions. Hence the
1733 end result is that kernel runs from a physical address meeting
1734 above alignment restrictions.
1736 Don't change this unless you know what you are doing.
1739 bool "Support for hot-pluggable CPUs"
1742 Say Y here to allow turning CPUs off and on. CPUs can be
1743 controlled through /sys/devices/system/cpu.
1744 ( Note: power management support will enable this option
1745 automatically on SMP systems. )
1746 Say N if you want to disable CPU hotplug.
1748 config BOOTPARAM_HOTPLUG_CPU0
1749 bool "Set default setting of cpu0_hotpluggable"
1751 depends on HOTPLUG_CPU
1753 Set whether default state of cpu0_hotpluggable is on or off.
1755 Say Y here to enable CPU0 hotplug by default. If this switch
1756 is turned on, there is no need to give cpu0_hotplug kernel
1757 parameter and the CPU0 hotplug feature is enabled by default.
1759 Please note: there are two known CPU0 dependencies if you want
1760 to enable the CPU0 hotplug feature either by this switch or by
1761 cpu0_hotplug kernel parameter.
1763 First, resume from hibernate or suspend always starts from CPU0.
1764 So hibernate and suspend are prevented if CPU0 is offline.
1766 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1767 offline if any interrupt can not migrate out of CPU0. There may
1768 be other CPU0 dependencies.
1770 Please make sure the dependencies are under your control before
1771 you enable this feature.
1773 Say N if you don't want to enable CPU0 hotplug feature by default.
1774 You still can enable the CPU0 hotplug feature at boot by kernel
1775 parameter cpu0_hotplug.
1777 config DEBUG_HOTPLUG_CPU0
1779 prompt "Debug CPU0 hotplug"
1780 depends on HOTPLUG_CPU
1782 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1783 soon as possible and boots up userspace with CPU0 offlined. User
1784 can online CPU0 back after boot time.
1786 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1787 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1788 compilation or giving cpu0_hotplug kernel parameter at boot.
1794 prompt "Compat VDSO support"
1795 depends on X86_32 || IA32_EMULATION
1797 Map the 32-bit VDSO to the predictable old-style address too.
1799 Say N here if you are running a sufficiently recent glibc
1800 version (2.3.3 or later), to remove the high-mapped
1801 VDSO mapping and to exclusively use the randomized VDSO.
1806 bool "Built-in kernel command line"
1808 Allow for specifying boot arguments to the kernel at
1809 build time. On some systems (e.g. embedded ones), it is
1810 necessary or convenient to provide some or all of the
1811 kernel boot arguments with the kernel itself (that is,
1812 to not rely on the boot loader to provide them.)
1814 To compile command line arguments into the kernel,
1815 set this option to 'Y', then fill in the
1816 the boot arguments in CONFIG_CMDLINE.
1818 Systems with fully functional boot loaders (i.e. non-embedded)
1819 should leave this option set to 'N'.
1822 string "Built-in kernel command string"
1823 depends on CMDLINE_BOOL
1826 Enter arguments here that should be compiled into the kernel
1827 image and used at boot time. If the boot loader provides a
1828 command line at boot time, it is appended to this string to
1829 form the full kernel command line, when the system boots.
1831 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1832 change this behavior.
1834 In most cases, the command line (whether built-in or provided
1835 by the boot loader) should specify the device for the root
1838 config CMDLINE_OVERRIDE
1839 bool "Built-in command line overrides boot loader arguments"
1840 depends on CMDLINE_BOOL
1842 Set this option to 'Y' to have the kernel ignore the boot loader
1843 command line, and use ONLY the built-in command line.
1845 This is used to work around broken boot loaders. This should
1846 be set to 'N' under normal conditions.
1850 config ARCH_ENABLE_MEMORY_HOTPLUG
1852 depends on X86_64 || (X86_32 && HIGHMEM)
1854 config ARCH_ENABLE_MEMORY_HOTREMOVE
1856 depends on MEMORY_HOTPLUG
1858 config USE_PERCPU_NUMA_NODE_ID
1862 menu "Power management and ACPI options"
1864 config ARCH_HIBERNATION_HEADER
1866 depends on X86_64 && HIBERNATION
1868 source "kernel/power/Kconfig"
1870 source "drivers/acpi/Kconfig"
1872 source "drivers/sfi/Kconfig"
1879 tristate "APM (Advanced Power Management) BIOS support"
1880 depends on X86_32 && PM_SLEEP
1882 APM is a BIOS specification for saving power using several different
1883 techniques. This is mostly useful for battery powered laptops with
1884 APM compliant BIOSes. If you say Y here, the system time will be
1885 reset after a RESUME operation, the /proc/apm device will provide
1886 battery status information, and user-space programs will receive
1887 notification of APM "events" (e.g. battery status change).
1889 If you select "Y" here, you can disable actual use of the APM
1890 BIOS by passing the "apm=off" option to the kernel at boot time.
1892 Note that the APM support is almost completely disabled for
1893 machines with more than one CPU.
1895 In order to use APM, you will need supporting software. For location
1896 and more information, read <file:Documentation/power/apm-acpi.txt>
1897 and the Battery Powered Linux mini-HOWTO, available from
1898 <http://www.tldp.org/docs.html#howto>.
1900 This driver does not spin down disk drives (see the hdparm(8)
1901 manpage ("man 8 hdparm") for that), and it doesn't turn off
1902 VESA-compliant "green" monitors.
1904 This driver does not support the TI 4000M TravelMate and the ACER
1905 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1906 desktop machines also don't have compliant BIOSes, and this driver
1907 may cause those machines to panic during the boot phase.
1909 Generally, if you don't have a battery in your machine, there isn't
1910 much point in using this driver and you should say N. If you get
1911 random kernel OOPSes or reboots that don't seem to be related to
1912 anything, try disabling/enabling this option (or disabling/enabling
1915 Some other things you should try when experiencing seemingly random,
1918 1) make sure that you have enough swap space and that it is
1920 2) pass the "no-hlt" option to the kernel
1921 3) switch on floating point emulation in the kernel and pass
1922 the "no387" option to the kernel
1923 4) pass the "floppy=nodma" option to the kernel
1924 5) pass the "mem=4M" option to the kernel (thereby disabling
1925 all but the first 4 MB of RAM)
1926 6) make sure that the CPU is not over clocked.
1927 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1928 8) disable the cache from your BIOS settings
1929 9) install a fan for the video card or exchange video RAM
1930 10) install a better fan for the CPU
1931 11) exchange RAM chips
1932 12) exchange the motherboard.
1934 To compile this driver as a module, choose M here: the
1935 module will be called apm.
1939 config APM_IGNORE_USER_SUSPEND
1940 bool "Ignore USER SUSPEND"
1942 This option will ignore USER SUSPEND requests. On machines with a
1943 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1944 series notebooks, it is necessary to say Y because of a BIOS bug.
1946 config APM_DO_ENABLE
1947 bool "Enable PM at boot time"
1949 Enable APM features at boot time. From page 36 of the APM BIOS
1950 specification: "When disabled, the APM BIOS does not automatically
1951 power manage devices, enter the Standby State, enter the Suspend
1952 State, or take power saving steps in response to CPU Idle calls."
1953 This driver will make CPU Idle calls when Linux is idle (unless this
1954 feature is turned off -- see "Do CPU IDLE calls", below). This
1955 should always save battery power, but more complicated APM features
1956 will be dependent on your BIOS implementation. You may need to turn
1957 this option off if your computer hangs at boot time when using APM
1958 support, or if it beeps continuously instead of suspending. Turn
1959 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1960 T400CDT. This is off by default since most machines do fine without
1965 bool "Make CPU Idle calls when idle"
1967 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1968 On some machines, this can activate improved power savings, such as
1969 a slowed CPU clock rate, when the machine is idle. These idle calls
1970 are made after the idle loop has run for some length of time (e.g.,
1971 333 mS). On some machines, this will cause a hang at boot time or
1972 whenever the CPU becomes idle. (On machines with more than one CPU,
1973 this option does nothing.)
1975 config APM_DISPLAY_BLANK
1976 bool "Enable console blanking using APM"
1978 Enable console blanking using the APM. Some laptops can use this to
1979 turn off the LCD backlight when the screen blanker of the Linux
1980 virtual console blanks the screen. Note that this is only used by
1981 the virtual console screen blanker, and won't turn off the backlight
1982 when using the X Window system. This also doesn't have anything to
1983 do with your VESA-compliant power-saving monitor. Further, this
1984 option doesn't work for all laptops -- it might not turn off your
1985 backlight at all, or it might print a lot of errors to the console,
1986 especially if you are using gpm.
1988 config APM_ALLOW_INTS
1989 bool "Allow interrupts during APM BIOS calls"
1991 Normally we disable external interrupts while we are making calls to
1992 the APM BIOS as a measure to lessen the effects of a badly behaving
1993 BIOS implementation. The BIOS should reenable interrupts if it
1994 needs to. Unfortunately, some BIOSes do not -- especially those in
1995 many of the newer IBM Thinkpads. If you experience hangs when you
1996 suspend, try setting this to Y. Otherwise, say N.
2000 source "drivers/cpufreq/Kconfig"
2002 source "drivers/cpuidle/Kconfig"
2004 source "drivers/idle/Kconfig"
2009 menu "Bus options (PCI etc.)"
2014 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
2016 Find out whether you have a PCI motherboard. PCI is the name of a
2017 bus system, i.e. the way the CPU talks to the other stuff inside
2018 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2019 VESA. If you have PCI, say Y, otherwise N.
2022 prompt "PCI access mode"
2023 depends on X86_32 && PCI
2026 On PCI systems, the BIOS can be used to detect the PCI devices and
2027 determine their configuration. However, some old PCI motherboards
2028 have BIOS bugs and may crash if this is done. Also, some embedded
2029 PCI-based systems don't have any BIOS at all. Linux can also try to
2030 detect the PCI hardware directly without using the BIOS.
2032 With this option, you can specify how Linux should detect the
2033 PCI devices. If you choose "BIOS", the BIOS will be used,
2034 if you choose "Direct", the BIOS won't be used, and if you
2035 choose "MMConfig", then PCI Express MMCONFIG will be used.
2036 If you choose "Any", the kernel will try MMCONFIG, then the
2037 direct access method and falls back to the BIOS if that doesn't
2038 work. If unsure, go with the default, which is "Any".
2043 config PCI_GOMMCONFIG
2060 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2062 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2065 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2069 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2073 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2077 depends on PCI && XEN
2085 bool "Support mmconfig PCI config space access"
2086 depends on X86_64 && PCI && ACPI
2088 config PCI_CNB20LE_QUIRK
2089 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2092 Read the PCI windows out of the CNB20LE host bridge. This allows
2093 PCI hotplug to work on systems with the CNB20LE chipset which do
2096 There's no public spec for this chipset, and this functionality
2097 is known to be incomplete.
2099 You should say N unless you know you need this.
2101 source "drivers/pci/pcie/Kconfig"
2103 source "drivers/pci/Kconfig"
2105 # x86_64 have no ISA slots, but can have ISA-style DMA.
2107 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2110 Enables ISA-style DMA support for devices requiring such controllers.
2118 Find out whether you have ISA slots on your motherboard. ISA is the
2119 name of a bus system, i.e. the way the CPU talks to the other stuff
2120 inside your box. Other bus systems are PCI, EISA, MicroChannel
2121 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2122 newer boards don't support it. If you have ISA, say Y, otherwise N.
2128 The Extended Industry Standard Architecture (EISA) bus was
2129 developed as an open alternative to the IBM MicroChannel bus.
2131 The EISA bus provided some of the features of the IBM MicroChannel
2132 bus while maintaining backward compatibility with cards made for
2133 the older ISA bus. The EISA bus saw limited use between 1988 and
2134 1995 when it was made obsolete by the PCI bus.
2136 Say Y here if you are building a kernel for an EISA-based machine.
2140 source "drivers/eisa/Kconfig"
2143 tristate "NatSemi SCx200 support"
2145 This provides basic support for National Semiconductor's
2146 (now AMD's) Geode processors. The driver probes for the
2147 PCI-IDs of several on-chip devices, so its a good dependency
2148 for other scx200_* drivers.
2150 If compiled as a module, the driver is named scx200.
2152 config SCx200HR_TIMER
2153 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2157 This driver provides a clocksource built upon the on-chip
2158 27MHz high-resolution timer. Its also a workaround for
2159 NSC Geode SC-1100's buggy TSC, which loses time when the
2160 processor goes idle (as is done by the scheduler). The
2161 other workaround is idle=poll boot option.
2164 bool "One Laptop Per Child support"
2171 Add support for detecting the unique features of the OLPC
2175 bool "OLPC XO-1 Power Management"
2176 depends on OLPC && MFD_CS5535 && PM_SLEEP
2179 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2182 bool "OLPC XO-1 Real Time Clock"
2183 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2185 Add support for the XO-1 real time clock, which can be used as a
2186 programmable wakeup source.
2189 bool "OLPC XO-1 SCI extras"
2190 depends on OLPC && OLPC_XO1_PM
2196 Add support for SCI-based features of the OLPC XO-1 laptop:
2197 - EC-driven system wakeups
2201 - AC adapter status updates
2202 - Battery status updates
2204 config OLPC_XO15_SCI
2205 bool "OLPC XO-1.5 SCI extras"
2206 depends on OLPC && ACPI
2209 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2210 - EC-driven system wakeups
2211 - AC adapter status updates
2212 - Battery status updates
2215 bool "PCEngines ALIX System Support (LED setup)"
2218 This option enables system support for the PCEngines ALIX.
2219 At present this just sets up LEDs for GPIO control on
2220 ALIX2/3/6 boards. However, other system specific setup should
2223 Note: You must still enable the drivers for GPIO and LED support
2224 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2226 Note: You have to set alix.force=1 for boards with Award BIOS.
2229 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2232 This option enables system support for the Soekris Engineering net5501.
2235 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2239 This option enables system support for the Traverse Technologies GEOS.
2242 bool "Technologic Systems TS-5500 platform support"
2244 select CHECK_SIGNATURE
2248 This option enables system support for the Technologic Systems TS-5500.
2254 depends on CPU_SUP_AMD && PCI
2256 source "drivers/pcmcia/Kconfig"
2258 source "drivers/pci/hotplug/Kconfig"
2261 bool "RapidIO support"
2265 If you say Y here, the kernel will include drivers and
2266 infrastructure code to support RapidIO interconnect devices.
2268 source "drivers/rapidio/Kconfig"
2273 menu "Executable file formats / Emulations"
2275 source "fs/Kconfig.binfmt"
2277 config IA32_EMULATION
2278 bool "IA32 Emulation"
2281 select COMPAT_BINFMT_ELF
2284 Include code to run legacy 32-bit programs under a
2285 64-bit kernel. You should likely turn this on, unless you're
2286 100% sure that you don't have any 32-bit programs left.
2289 tristate "IA32 a.out support"
2290 depends on IA32_EMULATION
2292 Support old a.out binaries in the 32bit emulation.
2295 bool "x32 ABI for 64-bit mode"
2296 depends on X86_64 && IA32_EMULATION
2298 Include code to run binaries for the x32 native 32-bit ABI
2299 for 64-bit processors. An x32 process gets access to the
2300 full 64-bit register file and wide data path while leaving
2301 pointers at 32 bits for smaller memory footprint.
2303 You will need a recent binutils (2.22 or later) with
2304 elf32_x86_64 support enabled to compile a kernel with this
2309 depends on IA32_EMULATION || X86_X32
2310 select ARCH_WANT_OLD_COMPAT_IPC
2313 config COMPAT_FOR_U64_ALIGNMENT
2316 config SYSVIPC_COMPAT
2328 config HAVE_ATOMIC_IOMAP
2332 config HAVE_TEXT_POKE_SMP
2334 select STOP_MACHINE if SMP
2336 config X86_DEV_DMA_OPS
2338 depends on X86_64 || STA2X11
2340 config X86_DMA_REMAP
2344 source "net/Kconfig"
2346 source "drivers/Kconfig"
2348 source "drivers/firmware/Kconfig"
2352 source "arch/x86/Kconfig.debug"
2354 source "security/Kconfig"
2356 source "crypto/Kconfig"
2358 source "arch/x86/kvm/Kconfig"
2360 source "lib/Kconfig"
projects / platform / adaptation / renesas_rcar / renesas_kernel.git / blob