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
19 select ARCH_USE_CMPXCHG_LOCKREF
24 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
25 select ARCH_MIGHT_HAVE_PC_PARPORT
26 select HAVE_AOUT if X86_32
27 select HAVE_UNSTABLE_SCHED_CLOCK
28 select ARCH_SUPPORTS_NUMA_BALANCING
29 select ARCH_SUPPORTS_INT128 if X86_64
30 select ARCH_WANTS_PROT_NUMA_PROT_NONE
33 select HAVE_PCSPKR_PLATFORM
34 select HAVE_PERF_EVENTS
35 select HAVE_IOREMAP_PROT
38 select HAVE_MEMBLOCK_NODE_MAP
39 select ARCH_DISCARD_MEMBLOCK
40 select ARCH_WANT_OPTIONAL_GPIOLIB
41 select ARCH_WANT_FRAME_POINTERS
43 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
44 select HAVE_KRETPROBES
46 select HAVE_KPROBES_ON_FTRACE
47 select HAVE_FTRACE_MCOUNT_RECORD
48 select HAVE_FENTRY if X86_64
49 select HAVE_C_RECORDMCOUNT
50 select HAVE_DYNAMIC_FTRACE
51 select HAVE_DYNAMIC_FTRACE_WITH_REGS
52 select HAVE_FUNCTION_TRACER
53 select HAVE_FUNCTION_GRAPH_TRACER
54 select HAVE_FUNCTION_GRAPH_FP_TEST
55 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
56 select HAVE_SYSCALL_TRACEPOINTS
57 select SYSCTL_EXCEPTION_TRACE
60 select HAVE_ARCH_TRACEHOOK
61 select HAVE_GENERIC_DMA_COHERENT if X86_32
62 select HAVE_EFFICIENT_UNALIGNED_ACCESS
63 select USER_STACKTRACE_SUPPORT
64 select HAVE_REGS_AND_STACK_ACCESS_API
65 select HAVE_DMA_API_DEBUG
66 select HAVE_KERNEL_GZIP
67 select HAVE_KERNEL_BZIP2
68 select HAVE_KERNEL_LZMA
70 select HAVE_KERNEL_LZO
71 select HAVE_KERNEL_LZ4
72 select HAVE_HW_BREAKPOINT
73 select HAVE_MIXED_BREAKPOINTS_REGS
75 select HAVE_PERF_EVENTS_NMI
77 select HAVE_PERF_USER_STACK_DUMP
78 select HAVE_DEBUG_KMEMLEAK
80 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
81 select HAVE_CMPXCHG_LOCAL
82 select HAVE_CMPXCHG_DOUBLE
83 select HAVE_ARCH_KMEMCHECK
84 select HAVE_USER_RETURN_NOTIFIER
85 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
86 select HAVE_ARCH_JUMP_LABEL
87 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
89 select GENERIC_FIND_FIRST_BIT
90 select GENERIC_IRQ_PROBE
91 select GENERIC_PENDING_IRQ if SMP
92 select GENERIC_IRQ_SHOW
93 select GENERIC_CLOCKEVENTS_MIN_ADJUST
94 select IRQ_FORCED_THREADING
95 select HAVE_BPF_JIT if X86_64
96 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
98 select ARCH_HAVE_NMI_SAFE_CMPXCHG
100 select DCACHE_WORD_ACCESS
101 select GENERIC_SMP_IDLE_THREAD
102 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
103 select HAVE_ARCH_SECCOMP_FILTER
104 select BUILDTIME_EXTABLE_SORT
105 select GENERIC_CMOS_UPDATE
106 select HAVE_ARCH_SOFT_DIRTY
107 select CLOCKSOURCE_WATCHDOG
108 select GENERIC_CLOCKEVENTS
109 select ARCH_CLOCKSOURCE_DATA if X86_64
110 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
111 select GENERIC_TIME_VSYSCALL if X86_64
112 select KTIME_SCALAR if X86_32
113 select GENERIC_STRNCPY_FROM_USER
114 select GENERIC_STRNLEN_USER
115 select HAVE_CONTEXT_TRACKING if X86_64
116 select HAVE_IRQ_TIME_ACCOUNTING
118 select MODULES_USE_ELF_REL if X86_32
119 select MODULES_USE_ELF_RELA if X86_64
120 select CLONE_BACKWARDS if X86_32
121 select ARCH_USE_BUILTIN_BSWAP
122 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
123 select OLD_SIGACTION if X86_32
124 select COMPAT_OLD_SIGACTION if IA32_EMULATION
126 select HAVE_DEBUG_STACKOVERFLOW
127 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
129 config INSTRUCTION_DECODER
131 depends on KPROBES || PERF_EVENTS || UPROBES
135 default "elf32-i386" if X86_32
136 default "elf64-x86-64" if X86_64
138 config ARCH_DEFCONFIG
140 default "arch/x86/configs/i386_defconfig" if X86_32
141 default "arch/x86/configs/x86_64_defconfig" if X86_64
143 config LOCKDEP_SUPPORT
146 config STACKTRACE_SUPPORT
149 config HAVE_LATENCYTOP_SUPPORT
158 config NEED_DMA_MAP_STATE
160 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
162 config NEED_SG_DMA_LENGTH
165 config GENERIC_ISA_DMA
167 depends on ISA_DMA_API
172 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
174 config GENERIC_BUG_RELATIVE_POINTERS
177 config GENERIC_HWEIGHT
180 config ARCH_MAY_HAVE_PC_FDC
182 depends on ISA_DMA_API
184 config RWSEM_XCHGADD_ALGORITHM
187 config GENERIC_CALIBRATE_DELAY
190 config ARCH_HAS_CPU_RELAX
193 config ARCH_HAS_CACHE_LINE_SIZE
196 config ARCH_HAS_CPU_AUTOPROBE
199 config HAVE_SETUP_PER_CPU_AREA
202 config NEED_PER_CPU_EMBED_FIRST_CHUNK
205 config NEED_PER_CPU_PAGE_FIRST_CHUNK
208 config ARCH_HIBERNATION_POSSIBLE
211 config ARCH_SUSPEND_POSSIBLE
214 config ARCH_WANT_HUGE_PMD_SHARE
217 config ARCH_WANT_GENERAL_HUGETLB
228 config ARCH_SUPPORTS_OPTIMIZED_INLINING
231 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
234 config HAVE_INTEL_TXT
236 depends on INTEL_IOMMU && ACPI
240 depends on X86_32 && SMP
244 depends on X86_64 && SMP
250 config X86_32_LAZY_GS
252 depends on X86_32 && !CC_STACKPROTECTOR
254 config ARCH_HWEIGHT_CFLAGS
256 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
257 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
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"
484 Select to build support for Intel Low Power Subsystem such as
485 found on Intel Lynxpoint PCH. Selecting this option enables
486 things like clock tree (common clock framework) and pincontrol
487 which are needed by the LPSS peripheral drivers.
490 bool "RDC R-321x SoC"
492 depends on X86_EXTENDED_PLATFORM
494 select X86_REBOOTFIXUPS
496 This option is needed for RDC R-321x system-on-chip, also known
498 If you don't have one of these chips, you should say N here.
500 config X86_32_NON_STANDARD
501 bool "Support non-standard 32-bit SMP architectures"
502 depends on X86_32 && SMP
503 depends on X86_EXTENDED_PLATFORM
505 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
506 STA2X11, default subarchitectures. It is intended for a generic
507 binary kernel. If you select them all, kernel will probe it
508 one by one and will fallback to default.
510 # Alphabetically sorted list of Non standard 32 bit platforms
513 bool "NUMAQ (IBM/Sequent)"
514 depends on X86_32_NON_STANDARD
519 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
520 NUMA multiquad box. This changes the way that processors are
521 bootstrapped, and uses Clustered Logical APIC addressing mode instead
522 of Flat Logical. You will need a new lynxer.elf file to flash your
523 firmware with - send email to <Martin.Bligh@us.ibm.com>.
525 config X86_SUPPORTS_MEMORY_FAILURE
527 # MCE code calls memory_failure():
529 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
530 depends on !X86_NUMAQ
531 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
532 depends on X86_64 || !SPARSEMEM
533 select ARCH_SUPPORTS_MEMORY_FAILURE
536 bool "SGI 320/540 (Visual Workstation)"
537 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
538 depends on X86_32_NON_STANDARD
540 The SGI Visual Workstation series is an IA32-based workstation
541 based on SGI systems chips with some legacy PC hardware attached.
543 Say Y here to create a kernel to run on the SGI 320 or 540.
545 A kernel compiled for the Visual Workstation will run on general
546 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
549 bool "STA2X11 Companion Chip Support"
550 depends on X86_32_NON_STANDARD && PCI
551 select X86_DEV_DMA_OPS
555 select ARCH_REQUIRE_GPIOLIB
558 This adds support for boards based on the STA2X11 IO-Hub,
559 a.k.a. "ConneXt". The chip is used in place of the standard
560 PC chipset, so all "standard" peripherals are missing. If this
561 option is selected the kernel will still be able to boot on
562 standard PC machines.
565 bool "Summit/EXA (IBM x440)"
566 depends on X86_32_NON_STANDARD
568 This option is needed for IBM systems that use the Summit/EXA chipset.
569 In particular, it is needed for the x440.
572 bool "Unisys ES7000 IA32 series"
573 depends on X86_32_NON_STANDARD && X86_BIGSMP
575 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
576 supposed to run on an IA32-based Unisys ES7000 system.
579 tristate "Eurobraille/Iris poweroff module"
582 The Iris machines from EuroBraille do not have APM or ACPI support
583 to shut themselves down properly. A special I/O sequence is
584 needed to do so, which is what this module does at
587 This is only for Iris machines from EuroBraille.
591 config SCHED_OMIT_FRAME_POINTER
593 prompt "Single-depth WCHAN output"
596 Calculate simpler /proc/<PID>/wchan values. If this option
597 is disabled then wchan values will recurse back to the
598 caller function. This provides more accurate wchan values,
599 at the expense of slightly more scheduling overhead.
601 If in doubt, say "Y".
603 menuconfig HYPERVISOR_GUEST
604 bool "Linux guest support"
606 Say Y here to enable options for running Linux under various hyper-
607 visors. This option enables basic hypervisor detection and platform
610 If you say N, all options in this submenu will be skipped and
611 disabled, and Linux guest support won't be built in.
616 bool "Enable paravirtualization code"
618 This changes the kernel so it can modify itself when it is run
619 under a hypervisor, potentially improving performance significantly
620 over full virtualization. However, when run without a hypervisor
621 the kernel is theoretically slower and slightly larger.
623 config PARAVIRT_DEBUG
624 bool "paravirt-ops debugging"
625 depends on PARAVIRT && DEBUG_KERNEL
627 Enable to debug paravirt_ops internals. Specifically, BUG if
628 a paravirt_op is missing when it is called.
630 config PARAVIRT_SPINLOCKS
631 bool "Paravirtualization layer for spinlocks"
632 depends on PARAVIRT && SMP
633 select UNINLINE_SPIN_UNLOCK
635 Paravirtualized spinlocks allow a pvops backend to replace the
636 spinlock implementation with something virtualization-friendly
637 (for example, block the virtual CPU rather than spinning).
639 It has a minimal impact on native kernels and gives a nice performance
640 benefit on paravirtualized KVM / Xen kernels.
642 If you are unsure how to answer this question, answer Y.
644 source "arch/x86/xen/Kconfig"
647 bool "KVM Guest support (including kvmclock)"
649 select PARAVIRT_CLOCK
652 This option enables various optimizations for running under the KVM
653 hypervisor. It includes a paravirtualized clock, so that instead
654 of relying on a PIT (or probably other) emulation by the
655 underlying device model, the host provides the guest with
656 timing infrastructure such as time of day, and system time
659 bool "Enable debug information for KVM Guests in debugfs"
660 depends on KVM_GUEST && DEBUG_FS
663 This option enables collection of various statistics for KVM guest.
664 Statistics are displayed in debugfs filesystem. Enabling this option
665 may incur significant overhead.
667 source "arch/x86/lguest/Kconfig"
669 config PARAVIRT_TIME_ACCOUNTING
670 bool "Paravirtual steal time accounting"
674 Select this option to enable fine granularity task steal time
675 accounting. Time spent executing other tasks in parallel with
676 the current vCPU is discounted from the vCPU power. To account for
677 that, there can be a small performance impact.
679 If in doubt, say N here.
681 config PARAVIRT_CLOCK
684 endif #HYPERVISOR_GUEST
692 This option adds a kernel parameter 'memtest', which allows memtest
694 memtest=0, mean disabled; -- default
695 memtest=1, mean do 1 test pattern;
697 memtest=4, mean do 4 test patterns.
698 If you are unsure how to answer this question, answer N.
700 config X86_SUMMIT_NUMA
702 depends on X86_32 && NUMA && X86_32_NON_STANDARD
704 config X86_CYCLONE_TIMER
706 depends on X86_SUMMIT
708 source "arch/x86/Kconfig.cpu"
712 prompt "HPET Timer Support" if X86_32
714 Use the IA-PC HPET (High Precision Event Timer) to manage
715 time in preference to the PIT and RTC, if a HPET is
717 HPET is the next generation timer replacing legacy 8254s.
718 The HPET provides a stable time base on SMP
719 systems, unlike the TSC, but it is more expensive to access,
720 as it is off-chip. You can find the HPET spec at
721 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
723 You can safely choose Y here. However, HPET will only be
724 activated if the platform and the BIOS support this feature.
725 Otherwise the 8254 will be used for timing services.
727 Choose N to continue using the legacy 8254 timer.
729 config HPET_EMULATE_RTC
731 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
734 def_bool y if X86_INTEL_MID
735 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
737 depends on X86_INTEL_MID && SFI
739 APB timer is the replacement for 8254, HPET on X86 MID platforms.
740 The APBT provides a stable time base on SMP
741 systems, unlike the TSC, but it is more expensive to access,
742 as it is off-chip. APB timers are always running regardless of CPU
743 C states, they are used as per CPU clockevent device when possible.
745 # Mark as expert because too many people got it wrong.
746 # The code disables itself when not needed.
749 bool "Enable DMI scanning" if EXPERT
751 Enabled scanning of DMI to identify machine quirks. Say Y
752 here unless you have verified that your setup is not
753 affected by entries in the DMI blacklist. Required by PNP
757 bool "Old AMD GART IOMMU support"
759 depends on X86_64 && PCI && AMD_NB
761 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
762 GART based hardware IOMMUs.
764 The GART supports full DMA access for devices with 32-bit access
765 limitations, on systems with more than 3 GB. This is usually needed
766 for USB, sound, many IDE/SATA chipsets and some other devices.
768 Newer systems typically have a modern AMD IOMMU, supported via
769 the CONFIG_AMD_IOMMU=y config option.
771 In normal configurations this driver is only active when needed:
772 there's more than 3 GB of memory and the system contains a
773 32-bit limited device.
778 bool "IBM Calgary IOMMU support"
780 depends on X86_64 && PCI
782 Support for hardware IOMMUs in IBM's xSeries x366 and x460
783 systems. Needed to run systems with more than 3GB of memory
784 properly with 32-bit PCI devices that do not support DAC
785 (Double Address Cycle). Calgary also supports bus level
786 isolation, where all DMAs pass through the IOMMU. This
787 prevents them from going anywhere except their intended
788 destination. This catches hard-to-find kernel bugs and
789 mis-behaving drivers and devices that do not use the DMA-API
790 properly to set up their DMA buffers. The IOMMU can be
791 turned off at boot time with the iommu=off parameter.
792 Normally the kernel will make the right choice by itself.
795 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
797 prompt "Should Calgary be enabled by default?"
798 depends on CALGARY_IOMMU
800 Should Calgary be enabled by default? if you choose 'y', Calgary
801 will be used (if it exists). If you choose 'n', Calgary will not be
802 used even if it exists. If you choose 'n' and would like to use
803 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
806 # need this always selected by IOMMU for the VIA workaround
810 Support for software bounce buffers used on x86-64 systems
811 which don't have a hardware IOMMU. Using this PCI devices
812 which can only access 32-bits of memory can be used on systems
813 with more than 3 GB of memory.
818 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
821 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
822 depends on X86_64 && SMP && DEBUG_KERNEL
823 select CPUMASK_OFFSTACK
825 Enable maximum number of CPUS and NUMA Nodes for this architecture.
829 int "Maximum number of CPUs" if SMP && !MAXSMP
830 range 2 8 if SMP && X86_32 && !X86_BIGSMP
831 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
832 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
834 default "8192" if MAXSMP
835 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
838 This allows you to specify the maximum number of CPUs which this
839 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
840 supported value is 4096, otherwise the maximum value is 512. The
841 minimum value which makes sense is 2.
843 This is purely to save memory - each supported CPU adds
844 approximately eight kilobytes to the kernel image.
847 bool "SMT (Hyperthreading) scheduler support"
850 SMT scheduler support improves the CPU scheduler's decision making
851 when dealing with Intel Pentium 4 chips with HyperThreading at a
852 cost of slightly increased overhead in some places. If unsure say
857 prompt "Multi-core scheduler support"
860 Multi-core scheduler support improves the CPU scheduler's decision
861 making when dealing with multi-core CPU chips at a cost of slightly
862 increased overhead in some places. If unsure say N here.
864 source "kernel/Kconfig.preempt"
867 bool "Local APIC support on uniprocessors"
868 depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI
870 A local APIC (Advanced Programmable Interrupt Controller) is an
871 integrated interrupt controller in the CPU. If you have a single-CPU
872 system which has a processor with a local APIC, you can say Y here to
873 enable and use it. If you say Y here even though your machine doesn't
874 have a local APIC, then the kernel will still run with no slowdown at
875 all. The local APIC supports CPU-generated self-interrupts (timer,
876 performance counters), and the NMI watchdog which detects hard
880 bool "IO-APIC support on uniprocessors"
881 depends on X86_UP_APIC
883 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
884 SMP-capable replacement for PC-style interrupt controllers. Most
885 SMP systems and many recent uniprocessor systems have one.
887 If you have a single-CPU system with an IO-APIC, you can say Y here
888 to use it. If you say Y here even though your machine doesn't have
889 an IO-APIC, then the kernel will still run with no slowdown at all.
891 config X86_LOCAL_APIC
893 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
897 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
899 config X86_VISWS_APIC
901 depends on X86_32 && X86_VISWS
903 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
904 bool "Reroute for broken boot IRQs"
905 depends on X86_IO_APIC
907 This option enables a workaround that fixes a source of
908 spurious interrupts. This is recommended when threaded
909 interrupt handling is used on systems where the generation of
910 superfluous "boot interrupts" cannot be disabled.
912 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
913 entry in the chipset's IO-APIC is masked (as, e.g. the RT
914 kernel does during interrupt handling). On chipsets where this
915 boot IRQ generation cannot be disabled, this workaround keeps
916 the original IRQ line masked so that only the equivalent "boot
917 IRQ" is delivered to the CPUs. The workaround also tells the
918 kernel to set up the IRQ handler on the boot IRQ line. In this
919 way only one interrupt is delivered to the kernel. Otherwise
920 the spurious second interrupt may cause the kernel to bring
921 down (vital) interrupt lines.
923 Only affects "broken" chipsets. Interrupt sharing may be
924 increased on these systems.
927 bool "Machine Check / overheating reporting"
930 Machine Check support allows the processor to notify the
931 kernel if it detects a problem (e.g. overheating, data corruption).
932 The action the kernel takes depends on the severity of the problem,
933 ranging from warning messages to halting the machine.
937 prompt "Intel MCE features"
938 depends on X86_MCE && X86_LOCAL_APIC
940 Additional support for intel specific MCE features such as
945 prompt "AMD MCE features"
946 depends on X86_MCE && X86_LOCAL_APIC
948 Additional support for AMD specific MCE features such as
949 the DRAM Error Threshold.
951 config X86_ANCIENT_MCE
952 bool "Support for old Pentium 5 / WinChip machine checks"
953 depends on X86_32 && X86_MCE
955 Include support for machine check handling on old Pentium 5 or WinChip
956 systems. These typically need to be enabled explicitely on the command
959 config X86_MCE_THRESHOLD
960 depends on X86_MCE_AMD || X86_MCE_INTEL
963 config X86_MCE_INJECT
965 tristate "Machine check injector support"
967 Provide support for injecting machine checks for testing purposes.
968 If you don't know what a machine check is and you don't do kernel
969 QA it is safe to say n.
971 config X86_THERMAL_VECTOR
973 depends on X86_MCE_INTEL
976 bool "Enable VM86 support" if EXPERT
980 This option is required by programs like DOSEMU to run 16-bit legacy
981 code on X86 processors. It also may be needed by software like
982 XFree86 to initialize some video cards via BIOS. Disabling this
983 option saves about 6k.
986 tristate "Toshiba Laptop support"
989 This adds a driver to safely access the System Management Mode of
990 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
991 not work on models with a Phoenix BIOS. The System Management Mode
992 is used to set the BIOS and power saving options on Toshiba portables.
994 For information on utilities to make use of this driver see the
995 Toshiba Linux utilities web site at:
996 <http://www.buzzard.org.uk/toshiba/>.
998 Say Y if you intend to run this kernel on a Toshiba portable.
1002 tristate "Dell laptop support"
1005 This adds a driver to safely access the System Management Mode
1006 of the CPU on the Dell Inspiron 8000. The System Management Mode
1007 is used to read cpu temperature and cooling fan status and to
1008 control the fans on the I8K portables.
1010 This driver has been tested only on the Inspiron 8000 but it may
1011 also work with other Dell laptops. You can force loading on other
1012 models by passing the parameter `force=1' to the module. Use at
1015 For information on utilities to make use of this driver see the
1016 I8K Linux utilities web site at:
1017 <http://people.debian.org/~dz/i8k/>
1019 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1022 config X86_REBOOTFIXUPS
1023 bool "Enable X86 board specific fixups for reboot"
1026 This enables chipset and/or board specific fixups to be done
1027 in order to get reboot to work correctly. This is only needed on
1028 some combinations of hardware and BIOS. The symptom, for which
1029 this config is intended, is when reboot ends with a stalled/hung
1032 Currently, the only fixup is for the Geode machines using
1033 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1035 Say Y if you want to enable the fixup. Currently, it's safe to
1036 enable this option even if you don't need it.
1040 tristate "CPU microcode loading support"
1041 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1045 If you say Y here, you will be able to update the microcode on
1046 certain Intel and AMD processors. The Intel support is for the
1047 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1048 Xeon etc. The AMD support is for families 0x10 and later. You will
1049 obviously need the actual microcode binary data itself which is not
1050 shipped with the Linux kernel.
1052 This option selects the general module only, you need to select
1053 at least one vendor specific module as well.
1055 To compile this driver as a module, choose M here: the module
1056 will be called microcode.
1058 config MICROCODE_INTEL
1059 bool "Intel microcode loading support"
1060 depends on MICROCODE
1064 This options enables microcode patch loading support for Intel
1067 For latest news and information on obtaining all the required
1068 Intel ingredients for this driver, check:
1069 <http://www.urbanmyth.org/microcode/>.
1071 config MICROCODE_AMD
1072 bool "AMD microcode loading support"
1073 depends on MICROCODE
1076 If you select this option, microcode patch loading support for AMD
1077 processors will be enabled.
1079 config MICROCODE_OLD_INTERFACE
1081 depends on MICROCODE
1083 config MICROCODE_INTEL_LIB
1085 depends on MICROCODE_INTEL
1087 config MICROCODE_INTEL_EARLY
1090 config MICROCODE_AMD_EARLY
1093 config MICROCODE_EARLY
1094 bool "Early load microcode"
1095 depends on MICROCODE=y && BLK_DEV_INITRD
1096 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1097 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1100 This option provides functionality to read additional microcode data
1101 at the beginning of initrd image. The data tells kernel to load
1102 microcode to CPU's as early as possible. No functional change if no
1103 microcode data is glued to the initrd, therefore it's safe to say Y.
1106 tristate "/dev/cpu/*/msr - Model-specific register support"
1108 This device gives privileged processes access to the x86
1109 Model-Specific Registers (MSRs). It is a character device with
1110 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1111 MSR accesses are directed to a specific CPU on multi-processor
1115 tristate "/dev/cpu/*/cpuid - CPU information support"
1117 This device gives processes access to the x86 CPUID instruction to
1118 be executed on a specific processor. It is a character device
1119 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1123 prompt "High Memory Support"
1124 default HIGHMEM64G if X86_NUMAQ
1130 depends on !X86_NUMAQ
1132 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1133 However, the address space of 32-bit x86 processors is only 4
1134 Gigabytes large. That means that, if you have a large amount of
1135 physical memory, not all of it can be "permanently mapped" by the
1136 kernel. The physical memory that's not permanently mapped is called
1139 If you are compiling a kernel which will never run on a machine with
1140 more than 1 Gigabyte total physical RAM, answer "off" here (default
1141 choice and suitable for most users). This will result in a "3GB/1GB"
1142 split: 3GB are mapped so that each process sees a 3GB virtual memory
1143 space and the remaining part of the 4GB virtual memory space is used
1144 by the kernel to permanently map as much physical memory as
1147 If the machine has between 1 and 4 Gigabytes physical RAM, then
1150 If more than 4 Gigabytes is used then answer "64GB" here. This
1151 selection turns Intel PAE (Physical Address Extension) mode on.
1152 PAE implements 3-level paging on IA32 processors. PAE is fully
1153 supported by Linux, PAE mode is implemented on all recent Intel
1154 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1155 then the kernel will not boot on CPUs that don't support PAE!
1157 The actual amount of total physical memory will either be
1158 auto detected or can be forced by using a kernel command line option
1159 such as "mem=256M". (Try "man bootparam" or see the documentation of
1160 your boot loader (lilo or loadlin) about how to pass options to the
1161 kernel at boot time.)
1163 If unsure, say "off".
1167 depends on !X86_NUMAQ
1169 Select this if you have a 32-bit processor and between 1 and 4
1170 gigabytes of physical RAM.
1177 Select this if you have a 32-bit processor and more than 4
1178 gigabytes of physical RAM.
1183 prompt "Memory split" if EXPERT
1187 Select the desired split between kernel and user memory.
1189 If the address range available to the kernel is less than the
1190 physical memory installed, the remaining memory will be available
1191 as "high memory". Accessing high memory is a little more costly
1192 than low memory, as it needs to be mapped into the kernel first.
1193 Note that increasing the kernel address space limits the range
1194 available to user programs, making the address space there
1195 tighter. Selecting anything other than the default 3G/1G split
1196 will also likely make your kernel incompatible with binary-only
1199 If you are not absolutely sure what you are doing, leave this
1203 bool "3G/1G user/kernel split"
1204 config VMSPLIT_3G_OPT
1206 bool "3G/1G user/kernel split (for full 1G low memory)"
1208 bool "2G/2G user/kernel split"
1209 config VMSPLIT_2G_OPT
1211 bool "2G/2G user/kernel split (for full 2G low memory)"
1213 bool "1G/3G user/kernel split"
1218 default 0xB0000000 if VMSPLIT_3G_OPT
1219 default 0x80000000 if VMSPLIT_2G
1220 default 0x78000000 if VMSPLIT_2G_OPT
1221 default 0x40000000 if VMSPLIT_1G
1227 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1230 bool "PAE (Physical Address Extension) Support"
1231 depends on X86_32 && !HIGHMEM4G
1233 PAE is required for NX support, and furthermore enables
1234 larger swapspace support for non-overcommit purposes. It
1235 has the cost of more pagetable lookup overhead, and also
1236 consumes more pagetable space per process.
1238 config ARCH_PHYS_ADDR_T_64BIT
1240 depends on X86_64 || X86_PAE
1242 config ARCH_DMA_ADDR_T_64BIT
1244 depends on X86_64 || HIGHMEM64G
1246 config DIRECT_GBPAGES
1247 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1251 Allow the kernel linear mapping to use 1GB pages on CPUs that
1252 support it. This can improve the kernel's performance a tiny bit by
1253 reducing TLB pressure. If in doubt, say "Y".
1255 # Common NUMA Features
1257 bool "Numa Memory Allocation and Scheduler Support"
1259 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI))
1260 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1262 Enable NUMA (Non Uniform Memory Access) support.
1264 The kernel will try to allocate memory used by a CPU on the
1265 local memory controller of the CPU and add some more
1266 NUMA awareness to the kernel.
1268 For 64-bit this is recommended if the system is Intel Core i7
1269 (or later), AMD Opteron, or EM64T NUMA.
1271 For 32-bit this is only needed on (rare) 32-bit-only platforms
1272 that support NUMA topologies, such as NUMAQ / Summit, or if you
1273 boot a 32-bit kernel on a 64-bit NUMA platform.
1275 Otherwise, you should say N.
1277 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1278 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1282 prompt "Old style AMD Opteron NUMA detection"
1283 depends on X86_64 && NUMA && PCI
1285 Enable AMD NUMA node topology detection. You should say Y here if
1286 you have a multi processor AMD system. This uses an old method to
1287 read the NUMA configuration directly from the builtin Northbridge
1288 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1289 which also takes priority if both are compiled in.
1291 config X86_64_ACPI_NUMA
1293 prompt "ACPI NUMA detection"
1294 depends on X86_64 && NUMA && ACPI && PCI
1297 Enable ACPI SRAT based node topology detection.
1299 # Some NUMA nodes have memory ranges that span
1300 # other nodes. Even though a pfn is valid and
1301 # between a node's start and end pfns, it may not
1302 # reside on that node. See memmap_init_zone()
1304 config NODES_SPAN_OTHER_NODES
1306 depends on X86_64_ACPI_NUMA
1309 bool "NUMA emulation"
1312 Enable NUMA emulation. A flat machine will be split
1313 into virtual nodes when booted with "numa=fake=N", where N is the
1314 number of nodes. This is only useful for debugging.
1317 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1319 default "10" if MAXSMP
1320 default "6" if X86_64
1321 default "4" if X86_NUMAQ
1323 depends on NEED_MULTIPLE_NODES
1325 Specify the maximum number of NUMA Nodes available on the target
1326 system. Increases memory reserved to accommodate various tables.
1328 config ARCH_HAVE_MEMORY_PRESENT
1330 depends on X86_32 && DISCONTIGMEM
1332 config NEED_NODE_MEMMAP_SIZE
1334 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1336 config ARCH_FLATMEM_ENABLE
1338 depends on X86_32 && !NUMA
1340 config ARCH_DISCONTIGMEM_ENABLE
1342 depends on NUMA && X86_32
1344 config ARCH_DISCONTIGMEM_DEFAULT
1346 depends on NUMA && X86_32
1348 config ARCH_SPARSEMEM_ENABLE
1350 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1351 select SPARSEMEM_STATIC if X86_32
1352 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1354 config ARCH_SPARSEMEM_DEFAULT
1358 config ARCH_SELECT_MEMORY_MODEL
1360 depends on ARCH_SPARSEMEM_ENABLE
1362 config ARCH_MEMORY_PROBE
1363 bool "Enable sysfs memory/probe interface"
1364 depends on X86_64 && MEMORY_HOTPLUG
1366 This option enables a sysfs memory/probe interface for testing.
1367 See Documentation/memory-hotplug.txt for more information.
1368 If you are unsure how to answer this question, answer N.
1370 config ARCH_PROC_KCORE_TEXT
1372 depends on X86_64 && PROC_KCORE
1374 config ILLEGAL_POINTER_VALUE
1377 default 0xdead000000000000 if X86_64
1382 bool "Allocate 3rd-level pagetables from highmem"
1385 The VM uses one page table entry for each page of physical memory.
1386 For systems with a lot of RAM, this can be wasteful of precious
1387 low memory. Setting this option will put user-space page table
1388 entries in high memory.
1390 config X86_CHECK_BIOS_CORRUPTION
1391 bool "Check for low memory corruption"
1393 Periodically check for memory corruption in low memory, which
1394 is suspected to be caused by BIOS. Even when enabled in the
1395 configuration, it is disabled at runtime. Enable it by
1396 setting "memory_corruption_check=1" on the kernel command
1397 line. By default it scans the low 64k of memory every 60
1398 seconds; see the memory_corruption_check_size and
1399 memory_corruption_check_period parameters in
1400 Documentation/kernel-parameters.txt to adjust this.
1402 When enabled with the default parameters, this option has
1403 almost no overhead, as it reserves a relatively small amount
1404 of memory and scans it infrequently. It both detects corruption
1405 and prevents it from affecting the running system.
1407 It is, however, intended as a diagnostic tool; if repeatable
1408 BIOS-originated corruption always affects the same memory,
1409 you can use memmap= to prevent the kernel from using that
1412 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1413 bool "Set the default setting of memory_corruption_check"
1414 depends on X86_CHECK_BIOS_CORRUPTION
1417 Set whether the default state of memory_corruption_check is
1420 config X86_RESERVE_LOW
1421 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1425 Specify the amount of low memory to reserve for the BIOS.
1427 The first page contains BIOS data structures that the kernel
1428 must not use, so that page must always be reserved.
1430 By default we reserve the first 64K of physical RAM, as a
1431 number of BIOSes are known to corrupt that memory range
1432 during events such as suspend/resume or monitor cable
1433 insertion, so it must not be used by the kernel.
1435 You can set this to 4 if you are absolutely sure that you
1436 trust the BIOS to get all its memory reservations and usages
1437 right. If you know your BIOS have problems beyond the
1438 default 64K area, you can set this to 640 to avoid using the
1439 entire low memory range.
1441 If you have doubts about the BIOS (e.g. suspend/resume does
1442 not work or there's kernel crashes after certain hardware
1443 hotplug events) then you might want to enable
1444 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1445 typical corruption patterns.
1447 Leave this to the default value of 64 if you are unsure.
1449 config MATH_EMULATION
1451 prompt "Math emulation" if X86_32
1453 Linux can emulate a math coprocessor (used for floating point
1454 operations) if you don't have one. 486DX and Pentium processors have
1455 a math coprocessor built in, 486SX and 386 do not, unless you added
1456 a 487DX or 387, respectively. (The messages during boot time can
1457 give you some hints here ["man dmesg"].) Everyone needs either a
1458 coprocessor or this emulation.
1460 If you don't have a math coprocessor, you need to say Y here; if you
1461 say Y here even though you have a coprocessor, the coprocessor will
1462 be used nevertheless. (This behavior can be changed with the kernel
1463 command line option "no387", which comes handy if your coprocessor
1464 is broken. Try "man bootparam" or see the documentation of your boot
1465 loader (lilo or loadlin) about how to pass options to the kernel at
1466 boot time.) This means that it is a good idea to say Y here if you
1467 intend to use this kernel on different machines.
1469 More information about the internals of the Linux math coprocessor
1470 emulation can be found in <file:arch/x86/math-emu/README>.
1472 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1473 kernel, it won't hurt.
1477 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1479 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1480 the Memory Type Range Registers (MTRRs) may be used to control
1481 processor access to memory ranges. This is most useful if you have
1482 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1483 allows bus write transfers to be combined into a larger transfer
1484 before bursting over the PCI/AGP bus. This can increase performance
1485 of image write operations 2.5 times or more. Saying Y here creates a
1486 /proc/mtrr file which may be used to manipulate your processor's
1487 MTRRs. Typically the X server should use this.
1489 This code has a reasonably generic interface so that similar
1490 control registers on other processors can be easily supported
1493 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1494 Registers (ARRs) which provide a similar functionality to MTRRs. For
1495 these, the ARRs are used to emulate the MTRRs.
1496 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1497 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1498 write-combining. All of these processors are supported by this code
1499 and it makes sense to say Y here if you have one of them.
1501 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1502 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1503 can lead to all sorts of problems, so it's good to say Y here.
1505 You can safely say Y even if your machine doesn't have MTRRs, you'll
1506 just add about 9 KB to your kernel.
1508 See <file:Documentation/x86/mtrr.txt> for more information.
1510 config MTRR_SANITIZER
1512 prompt "MTRR cleanup support"
1515 Convert MTRR layout from continuous to discrete, so X drivers can
1516 add writeback entries.
1518 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1519 The largest mtrr entry size for a continuous block can be set with
1524 config MTRR_SANITIZER_ENABLE_DEFAULT
1525 int "MTRR cleanup enable value (0-1)"
1528 depends on MTRR_SANITIZER
1530 Enable mtrr cleanup default value
1532 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1533 int "MTRR cleanup spare reg num (0-7)"
1536 depends on MTRR_SANITIZER
1538 mtrr cleanup spare entries default, it can be changed via
1539 mtrr_spare_reg_nr=N on the kernel command line.
1543 prompt "x86 PAT support" if EXPERT
1546 Use PAT attributes to setup page level cache control.
1548 PATs are the modern equivalents of MTRRs and are much more
1549 flexible than MTRRs.
1551 Say N here if you see bootup problems (boot crash, boot hang,
1552 spontaneous reboots) or a non-working video driver.
1556 config ARCH_USES_PG_UNCACHED
1562 prompt "x86 architectural random number generator" if EXPERT
1564 Enable the x86 architectural RDRAND instruction
1565 (Intel Bull Mountain technology) to generate random numbers.
1566 If supported, this is a high bandwidth, cryptographically
1567 secure hardware random number generator.
1571 prompt "Supervisor Mode Access Prevention" if EXPERT
1573 Supervisor Mode Access Prevention (SMAP) is a security
1574 feature in newer Intel processors. There is a small
1575 performance cost if this enabled and turned on; there is
1576 also a small increase in the kernel size if this is enabled.
1581 bool "EFI runtime service support"
1585 This enables the kernel to use EFI runtime services that are
1586 available (such as the EFI variable services).
1588 This option is only useful on systems that have EFI firmware.
1589 In addition, you should use the latest ELILO loader available
1590 at <http://elilo.sourceforge.net> in order to take advantage
1591 of EFI runtime services. However, even with this option, the
1592 resultant kernel should continue to boot on existing non-EFI
1596 bool "EFI stub support"
1599 This kernel feature allows a bzImage to be loaded directly
1600 by EFI firmware without the use of a bootloader.
1602 See Documentation/efi-stub.txt for more information.
1606 prompt "Enable seccomp to safely compute untrusted bytecode"
1608 This kernel feature is useful for number crunching applications
1609 that may need to compute untrusted bytecode during their
1610 execution. By using pipes or other transports made available to
1611 the process as file descriptors supporting the read/write
1612 syscalls, it's possible to isolate those applications in
1613 their own address space using seccomp. Once seccomp is
1614 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1615 and the task is only allowed to execute a few safe syscalls
1616 defined by each seccomp mode.
1618 If unsure, say Y. Only embedded should say N here.
1620 config CC_STACKPROTECTOR
1621 bool "Enable -fstack-protector buffer overflow detection"
1623 This option turns on the -fstack-protector GCC feature. This
1624 feature puts, at the beginning of functions, a canary value on
1625 the stack just before the return address, and validates
1626 the value just before actually returning. Stack based buffer
1627 overflows (that need to overwrite this return address) now also
1628 overwrite the canary, which gets detected and the attack is then
1629 neutralized via a kernel panic.
1631 This feature requires gcc version 4.2 or above, or a distribution
1632 gcc with the feature backported. Older versions are automatically
1633 detected and for those versions, this configuration option is
1634 ignored. (and a warning is printed during bootup)
1636 source kernel/Kconfig.hz
1639 bool "kexec system call"
1641 kexec is a system call that implements the ability to shutdown your
1642 current kernel, and to start another kernel. It is like a reboot
1643 but it is independent of the system firmware. And like a reboot
1644 you can start any kernel with it, not just Linux.
1646 The name comes from the similarity to the exec system call.
1648 It is an ongoing process to be certain the hardware in a machine
1649 is properly shutdown, so do not be surprised if this code does not
1650 initially work for you. As of this writing the exact hardware
1651 interface is strongly in flux, so no good recommendation can be
1655 bool "kernel crash dumps"
1656 depends on X86_64 || (X86_32 && HIGHMEM)
1658 Generate crash dump after being started by kexec.
1659 This should be normally only set in special crash dump kernels
1660 which are loaded in the main kernel with kexec-tools into
1661 a specially reserved region and then later executed after
1662 a crash by kdump/kexec. The crash dump kernel must be compiled
1663 to a memory address not used by the main kernel or BIOS using
1664 PHYSICAL_START, or it must be built as a relocatable image
1665 (CONFIG_RELOCATABLE=y).
1666 For more details see Documentation/kdump/kdump.txt
1670 depends on KEXEC && HIBERNATION
1672 Jump between original kernel and kexeced kernel and invoke
1673 code in physical address mode via KEXEC
1675 config PHYSICAL_START
1676 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1679 This gives the physical address where the kernel is loaded.
1681 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1682 bzImage will decompress itself to above physical address and
1683 run from there. Otherwise, bzImage will run from the address where
1684 it has been loaded by the boot loader and will ignore above physical
1687 In normal kdump cases one does not have to set/change this option
1688 as now bzImage can be compiled as a completely relocatable image
1689 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1690 address. This option is mainly useful for the folks who don't want
1691 to use a bzImage for capturing the crash dump and want to use a
1692 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1693 to be specifically compiled to run from a specific memory area
1694 (normally a reserved region) and this option comes handy.
1696 So if you are using bzImage for capturing the crash dump,
1697 leave the value here unchanged to 0x1000000 and set
1698 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1699 for capturing the crash dump change this value to start of
1700 the reserved region. In other words, it can be set based on
1701 the "X" value as specified in the "crashkernel=YM@XM"
1702 command line boot parameter passed to the panic-ed
1703 kernel. Please take a look at Documentation/kdump/kdump.txt
1704 for more details about crash dumps.
1706 Usage of bzImage for capturing the crash dump is recommended as
1707 one does not have to build two kernels. Same kernel can be used
1708 as production kernel and capture kernel. Above option should have
1709 gone away after relocatable bzImage support is introduced. But it
1710 is present because there are users out there who continue to use
1711 vmlinux for dump capture. This option should go away down the
1714 Don't change this unless you know what you are doing.
1717 bool "Build a relocatable kernel"
1720 This builds a kernel image that retains relocation information
1721 so it can be loaded someplace besides the default 1MB.
1722 The relocations tend to make the kernel binary about 10% larger,
1723 but are discarded at runtime.
1725 One use is for the kexec on panic case where the recovery kernel
1726 must live at a different physical address than the primary
1729 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1730 it has been loaded at and the compile time physical address
1731 (CONFIG_PHYSICAL_START) is ignored.
1733 # Relocation on x86-32 needs some additional build support
1734 config X86_NEED_RELOCS
1736 depends on X86_32 && RELOCATABLE
1738 config PHYSICAL_ALIGN
1739 hex "Alignment value to which kernel should be aligned"
1741 range 0x2000 0x1000000 if X86_32
1742 range 0x200000 0x1000000 if X86_64
1744 This value puts the alignment restrictions on physical address
1745 where kernel is loaded and run from. Kernel is compiled for an
1746 address which meets above alignment restriction.
1748 If bootloader loads the kernel at a non-aligned address and
1749 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1750 address aligned to above value and run from there.
1752 If bootloader loads the kernel at a non-aligned address and
1753 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1754 load address and decompress itself to the address it has been
1755 compiled for and run from there. The address for which kernel is
1756 compiled already meets above alignment restrictions. Hence the
1757 end result is that kernel runs from a physical address meeting
1758 above alignment restrictions.
1760 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1761 this value must be a multiple of 0x200000.
1763 Don't change this unless you know what you are doing.
1766 bool "Support for hot-pluggable CPUs"
1769 Say Y here to allow turning CPUs off and on. CPUs can be
1770 controlled through /sys/devices/system/cpu.
1771 ( Note: power management support will enable this option
1772 automatically on SMP systems. )
1773 Say N if you want to disable CPU hotplug.
1775 config BOOTPARAM_HOTPLUG_CPU0
1776 bool "Set default setting of cpu0_hotpluggable"
1778 depends on HOTPLUG_CPU
1780 Set whether default state of cpu0_hotpluggable is on or off.
1782 Say Y here to enable CPU0 hotplug by default. If this switch
1783 is turned on, there is no need to give cpu0_hotplug kernel
1784 parameter and the CPU0 hotplug feature is enabled by default.
1786 Please note: there are two known CPU0 dependencies if you want
1787 to enable the CPU0 hotplug feature either by this switch or by
1788 cpu0_hotplug kernel parameter.
1790 First, resume from hibernate or suspend always starts from CPU0.
1791 So hibernate and suspend are prevented if CPU0 is offline.
1793 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1794 offline if any interrupt can not migrate out of CPU0. There may
1795 be other CPU0 dependencies.
1797 Please make sure the dependencies are under your control before
1798 you enable this feature.
1800 Say N if you don't want to enable CPU0 hotplug feature by default.
1801 You still can enable the CPU0 hotplug feature at boot by kernel
1802 parameter cpu0_hotplug.
1804 config DEBUG_HOTPLUG_CPU0
1806 prompt "Debug CPU0 hotplug"
1807 depends on HOTPLUG_CPU
1809 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1810 soon as possible and boots up userspace with CPU0 offlined. User
1811 can online CPU0 back after boot time.
1813 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1814 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1815 compilation or giving cpu0_hotplug kernel parameter at boot.
1821 prompt "Compat VDSO support"
1822 depends on X86_32 || IA32_EMULATION
1824 Map the 32-bit VDSO to the predictable old-style address too.
1826 Say N here if you are running a sufficiently recent glibc
1827 version (2.3.3 or later), to remove the high-mapped
1828 VDSO mapping and to exclusively use the randomized VDSO.
1833 bool "Built-in kernel command line"
1835 Allow for specifying boot arguments to the kernel at
1836 build time. On some systems (e.g. embedded ones), it is
1837 necessary or convenient to provide some or all of the
1838 kernel boot arguments with the kernel itself (that is,
1839 to not rely on the boot loader to provide them.)
1841 To compile command line arguments into the kernel,
1842 set this option to 'Y', then fill in the
1843 the boot arguments in CONFIG_CMDLINE.
1845 Systems with fully functional boot loaders (i.e. non-embedded)
1846 should leave this option set to 'N'.
1849 string "Built-in kernel command string"
1850 depends on CMDLINE_BOOL
1853 Enter arguments here that should be compiled into the kernel
1854 image and used at boot time. If the boot loader provides a
1855 command line at boot time, it is appended to this string to
1856 form the full kernel command line, when the system boots.
1858 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1859 change this behavior.
1861 In most cases, the command line (whether built-in or provided
1862 by the boot loader) should specify the device for the root
1865 config CMDLINE_OVERRIDE
1866 bool "Built-in command line overrides boot loader arguments"
1867 depends on CMDLINE_BOOL
1869 Set this option to 'Y' to have the kernel ignore the boot loader
1870 command line, and use ONLY the built-in command line.
1872 This is used to work around broken boot loaders. This should
1873 be set to 'N' under normal conditions.
1877 config ARCH_ENABLE_MEMORY_HOTPLUG
1879 depends on X86_64 || (X86_32 && HIGHMEM)
1881 config ARCH_ENABLE_MEMORY_HOTREMOVE
1883 depends on MEMORY_HOTPLUG
1885 config USE_PERCPU_NUMA_NODE_ID
1889 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1891 depends on X86_64 || X86_PAE
1893 menu "Power management and ACPI options"
1895 config ARCH_HIBERNATION_HEADER
1897 depends on X86_64 && HIBERNATION
1899 source "kernel/power/Kconfig"
1901 source "drivers/acpi/Kconfig"
1903 source "drivers/sfi/Kconfig"
1910 tristate "APM (Advanced Power Management) BIOS support"
1911 depends on X86_32 && PM_SLEEP
1913 APM is a BIOS specification for saving power using several different
1914 techniques. This is mostly useful for battery powered laptops with
1915 APM compliant BIOSes. If you say Y here, the system time will be
1916 reset after a RESUME operation, the /proc/apm device will provide
1917 battery status information, and user-space programs will receive
1918 notification of APM "events" (e.g. battery status change).
1920 If you select "Y" here, you can disable actual use of the APM
1921 BIOS by passing the "apm=off" option to the kernel at boot time.
1923 Note that the APM support is almost completely disabled for
1924 machines with more than one CPU.
1926 In order to use APM, you will need supporting software. For location
1927 and more information, read <file:Documentation/power/apm-acpi.txt>
1928 and the Battery Powered Linux mini-HOWTO, available from
1929 <http://www.tldp.org/docs.html#howto>.
1931 This driver does not spin down disk drives (see the hdparm(8)
1932 manpage ("man 8 hdparm") for that), and it doesn't turn off
1933 VESA-compliant "green" monitors.
1935 This driver does not support the TI 4000M TravelMate and the ACER
1936 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1937 desktop machines also don't have compliant BIOSes, and this driver
1938 may cause those machines to panic during the boot phase.
1940 Generally, if you don't have a battery in your machine, there isn't
1941 much point in using this driver and you should say N. If you get
1942 random kernel OOPSes or reboots that don't seem to be related to
1943 anything, try disabling/enabling this option (or disabling/enabling
1946 Some other things you should try when experiencing seemingly random,
1949 1) make sure that you have enough swap space and that it is
1951 2) pass the "no-hlt" option to the kernel
1952 3) switch on floating point emulation in the kernel and pass
1953 the "no387" option to the kernel
1954 4) pass the "floppy=nodma" option to the kernel
1955 5) pass the "mem=4M" option to the kernel (thereby disabling
1956 all but the first 4 MB of RAM)
1957 6) make sure that the CPU is not over clocked.
1958 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1959 8) disable the cache from your BIOS settings
1960 9) install a fan for the video card or exchange video RAM
1961 10) install a better fan for the CPU
1962 11) exchange RAM chips
1963 12) exchange the motherboard.
1965 To compile this driver as a module, choose M here: the
1966 module will be called apm.
1970 config APM_IGNORE_USER_SUSPEND
1971 bool "Ignore USER SUSPEND"
1973 This option will ignore USER SUSPEND requests. On machines with a
1974 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1975 series notebooks, it is necessary to say Y because of a BIOS bug.
1977 config APM_DO_ENABLE
1978 bool "Enable PM at boot time"
1980 Enable APM features at boot time. From page 36 of the APM BIOS
1981 specification: "When disabled, the APM BIOS does not automatically
1982 power manage devices, enter the Standby State, enter the Suspend
1983 State, or take power saving steps in response to CPU Idle calls."
1984 This driver will make CPU Idle calls when Linux is idle (unless this
1985 feature is turned off -- see "Do CPU IDLE calls", below). This
1986 should always save battery power, but more complicated APM features
1987 will be dependent on your BIOS implementation. You may need to turn
1988 this option off if your computer hangs at boot time when using APM
1989 support, or if it beeps continuously instead of suspending. Turn
1990 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1991 T400CDT. This is off by default since most machines do fine without
1996 bool "Make CPU Idle calls when idle"
1998 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1999 On some machines, this can activate improved power savings, such as
2000 a slowed CPU clock rate, when the machine is idle. These idle calls
2001 are made after the idle loop has run for some length of time (e.g.,
2002 333 mS). On some machines, this will cause a hang at boot time or
2003 whenever the CPU becomes idle. (On machines with more than one CPU,
2004 this option does nothing.)
2006 config APM_DISPLAY_BLANK
2007 bool "Enable console blanking using APM"
2009 Enable console blanking using the APM. Some laptops can use this to
2010 turn off the LCD backlight when the screen blanker of the Linux
2011 virtual console blanks the screen. Note that this is only used by
2012 the virtual console screen blanker, and won't turn off the backlight
2013 when using the X Window system. This also doesn't have anything to
2014 do with your VESA-compliant power-saving monitor. Further, this
2015 option doesn't work for all laptops -- it might not turn off your
2016 backlight at all, or it might print a lot of errors to the console,
2017 especially if you are using gpm.
2019 config APM_ALLOW_INTS
2020 bool "Allow interrupts during APM BIOS calls"
2022 Normally we disable external interrupts while we are making calls to
2023 the APM BIOS as a measure to lessen the effects of a badly behaving
2024 BIOS implementation. The BIOS should reenable interrupts if it
2025 needs to. Unfortunately, some BIOSes do not -- especially those in
2026 many of the newer IBM Thinkpads. If you experience hangs when you
2027 suspend, try setting this to Y. Otherwise, say N.
2031 source "drivers/cpufreq/Kconfig"
2033 source "drivers/cpuidle/Kconfig"
2035 source "drivers/idle/Kconfig"
2040 menu "Bus options (PCI etc.)"
2046 Find out whether you have a PCI motherboard. PCI is the name of a
2047 bus system, i.e. the way the CPU talks to the other stuff inside
2048 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2049 VESA. If you have PCI, say Y, otherwise N.
2052 prompt "PCI access mode"
2053 depends on X86_32 && PCI
2056 On PCI systems, the BIOS can be used to detect the PCI devices and
2057 determine their configuration. However, some old PCI motherboards
2058 have BIOS bugs and may crash if this is done. Also, some embedded
2059 PCI-based systems don't have any BIOS at all. Linux can also try to
2060 detect the PCI hardware directly without using the BIOS.
2062 With this option, you can specify how Linux should detect the
2063 PCI devices. If you choose "BIOS", the BIOS will be used,
2064 if you choose "Direct", the BIOS won't be used, and if you
2065 choose "MMConfig", then PCI Express MMCONFIG will be used.
2066 If you choose "Any", the kernel will try MMCONFIG, then the
2067 direct access method and falls back to the BIOS if that doesn't
2068 work. If unsure, go with the default, which is "Any".
2073 config PCI_GOMMCONFIG
2090 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2092 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2095 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2099 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2103 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2107 depends on PCI && XEN
2115 bool "Support mmconfig PCI config space access"
2116 depends on X86_64 && PCI && ACPI
2118 config PCI_CNB20LE_QUIRK
2119 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2122 Read the PCI windows out of the CNB20LE host bridge. This allows
2123 PCI hotplug to work on systems with the CNB20LE chipset which do
2126 There's no public spec for this chipset, and this functionality
2127 is known to be incomplete.
2129 You should say N unless you know you need this.
2131 source "drivers/pci/pcie/Kconfig"
2133 source "drivers/pci/Kconfig"
2135 # x86_64 have no ISA slots, but can have ISA-style DMA.
2137 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2140 Enables ISA-style DMA support for devices requiring such controllers.
2148 Find out whether you have ISA slots on your motherboard. ISA is the
2149 name of a bus system, i.e. the way the CPU talks to the other stuff
2150 inside your box. Other bus systems are PCI, EISA, MicroChannel
2151 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2152 newer boards don't support it. If you have ISA, say Y, otherwise N.
2158 The Extended Industry Standard Architecture (EISA) bus was
2159 developed as an open alternative to the IBM MicroChannel bus.
2161 The EISA bus provided some of the features of the IBM MicroChannel
2162 bus while maintaining backward compatibility with cards made for
2163 the older ISA bus. The EISA bus saw limited use between 1988 and
2164 1995 when it was made obsolete by the PCI bus.
2166 Say Y here if you are building a kernel for an EISA-based machine.
2170 source "drivers/eisa/Kconfig"
2173 tristate "NatSemi SCx200 support"
2175 This provides basic support for National Semiconductor's
2176 (now AMD's) Geode processors. The driver probes for the
2177 PCI-IDs of several on-chip devices, so its a good dependency
2178 for other scx200_* drivers.
2180 If compiled as a module, the driver is named scx200.
2182 config SCx200HR_TIMER
2183 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2187 This driver provides a clocksource built upon the on-chip
2188 27MHz high-resolution timer. Its also a workaround for
2189 NSC Geode SC-1100's buggy TSC, which loses time when the
2190 processor goes idle (as is done by the scheduler). The
2191 other workaround is idle=poll boot option.
2194 bool "One Laptop Per Child support"
2201 Add support for detecting the unique features of the OLPC
2205 bool "OLPC XO-1 Power Management"
2206 depends on OLPC && MFD_CS5535 && PM_SLEEP
2209 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2212 bool "OLPC XO-1 Real Time Clock"
2213 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2215 Add support for the XO-1 real time clock, which can be used as a
2216 programmable wakeup source.
2219 bool "OLPC XO-1 SCI extras"
2220 depends on OLPC && OLPC_XO1_PM
2226 Add support for SCI-based features of the OLPC XO-1 laptop:
2227 - EC-driven system wakeups
2231 - AC adapter status updates
2232 - Battery status updates
2234 config OLPC_XO15_SCI
2235 bool "OLPC XO-1.5 SCI extras"
2236 depends on OLPC && ACPI
2239 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2240 - EC-driven system wakeups
2241 - AC adapter status updates
2242 - Battery status updates
2245 bool "PCEngines ALIX System Support (LED setup)"
2248 This option enables system support for the PCEngines ALIX.
2249 At present this just sets up LEDs for GPIO control on
2250 ALIX2/3/6 boards. However, other system specific setup should
2253 Note: You must still enable the drivers for GPIO and LED support
2254 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2256 Note: You have to set alix.force=1 for boards with Award BIOS.
2259 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2262 This option enables system support for the Soekris Engineering net5501.
2265 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2269 This option enables system support for the Traverse Technologies GEOS.
2272 bool "Technologic Systems TS-5500 platform support"
2274 select CHECK_SIGNATURE
2278 This option enables system support for the Technologic Systems TS-5500.
2284 depends on CPU_SUP_AMD && PCI
2286 source "drivers/pcmcia/Kconfig"
2288 source "drivers/pci/hotplug/Kconfig"
2291 tristate "RapidIO support"
2295 If enabled this option will include drivers and the core
2296 infrastructure code to support RapidIO interconnect devices.
2298 source "drivers/rapidio/Kconfig"
2301 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2303 Firmwares often provide initial graphics framebuffers so the BIOS,
2304 bootloader or kernel can show basic video-output during boot for
2305 user-guidance and debugging. Historically, x86 used the VESA BIOS
2306 Extensions and EFI-framebuffers for this, which are mostly limited
2308 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2309 framebuffers so the new generic system-framebuffer drivers can be
2310 used on x86. If the framebuffer is not compatible with the generic
2311 modes, it is adverticed as fallback platform framebuffer so legacy
2312 drivers like efifb, vesafb and uvesafb can pick it up.
2313 If this option is not selected, all system framebuffers are always
2314 marked as fallback platform framebuffers as usual.
2316 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2317 not be able to pick up generic system framebuffers if this option
2318 is selected. You are highly encouraged to enable simplefb as
2319 replacement if you select this option. simplefb can correctly deal
2320 with generic system framebuffers. But you should still keep vesafb
2321 and others enabled as fallback if a system framebuffer is
2322 incompatible with simplefb.
2329 menu "Executable file formats / Emulations"
2331 source "fs/Kconfig.binfmt"
2333 config IA32_EMULATION
2334 bool "IA32 Emulation"
2337 select COMPAT_BINFMT_ELF
2340 Include code to run legacy 32-bit programs under a
2341 64-bit kernel. You should likely turn this on, unless you're
2342 100% sure that you don't have any 32-bit programs left.
2345 tristate "IA32 a.out support"
2346 depends on IA32_EMULATION
2348 Support old a.out binaries in the 32bit emulation.
2351 bool "x32 ABI for 64-bit mode"
2352 depends on X86_64 && IA32_EMULATION
2354 Include code to run binaries for the x32 native 32-bit ABI
2355 for 64-bit processors. An x32 process gets access to the
2356 full 64-bit register file and wide data path while leaving
2357 pointers at 32 bits for smaller memory footprint.
2359 You will need a recent binutils (2.22 or later) with
2360 elf32_x86_64 support enabled to compile a kernel with this
2365 depends on IA32_EMULATION || X86_X32
2366 select ARCH_WANT_OLD_COMPAT_IPC
2369 config COMPAT_FOR_U64_ALIGNMENT
2372 config SYSVIPC_COMPAT
2384 config HAVE_ATOMIC_IOMAP
2388 config X86_DEV_DMA_OPS
2390 depends on X86_64 || STA2X11
2392 config X86_DMA_REMAP
2396 source "net/Kconfig"
2398 source "drivers/Kconfig"
2400 source "drivers/firmware/Kconfig"
2404 source "arch/x86/Kconfig.debug"
2406 source "security/Kconfig"
2408 source "crypto/Kconfig"
2410 source "arch/x86/kvm/Kconfig"
2412 source "lib/Kconfig"
projects / linux-drm-fsl-dcu.git / blob