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_MIGHT_HAVE_ACPI_PDC if ACPI
25 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
26 select ARCH_MIGHT_HAVE_PC_PARPORT
27 select ARCH_MIGHT_HAVE_PC_SERIO
28 select HAVE_AOUT if X86_32
29 select HAVE_UNSTABLE_SCHED_CLOCK
30 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
31 select ARCH_SUPPORTS_INT128 if X86_64
32 select ARCH_WANTS_PROT_NUMA_PROT_NONE
35 select HAVE_PCSPKR_PLATFORM
36 select HAVE_PERF_EVENTS
37 select HAVE_IOREMAP_PROT
40 select HAVE_MEMBLOCK_NODE_MAP
41 select ARCH_DISCARD_MEMBLOCK
42 select ARCH_WANT_OPTIONAL_GPIOLIB
43 select ARCH_WANT_FRAME_POINTERS
45 select HAVE_DMA_CONTIGUOUS
46 select HAVE_KRETPROBES
47 select GENERIC_EARLY_IOREMAP
49 select HAVE_KPROBES_ON_FTRACE
50 select HAVE_FTRACE_MCOUNT_RECORD
51 select HAVE_FENTRY if X86_64
52 select HAVE_C_RECORDMCOUNT
53 select HAVE_DYNAMIC_FTRACE
54 select HAVE_DYNAMIC_FTRACE_WITH_REGS
55 select HAVE_FUNCTION_TRACER
56 select HAVE_FUNCTION_GRAPH_TRACER
57 select HAVE_FUNCTION_GRAPH_FP_TEST
58 select HAVE_SYSCALL_TRACEPOINTS
59 select SYSCTL_EXCEPTION_TRACE
62 select HAVE_ARCH_TRACEHOOK
63 select HAVE_GENERIC_DMA_COHERENT if X86_32
64 select HAVE_EFFICIENT_UNALIGNED_ACCESS
65 select USER_STACKTRACE_SUPPORT
66 select HAVE_REGS_AND_STACK_ACCESS_API
67 select HAVE_DMA_API_DEBUG
68 select HAVE_KERNEL_GZIP
69 select HAVE_KERNEL_BZIP2
70 select HAVE_KERNEL_LZMA
72 select HAVE_KERNEL_LZO
73 select HAVE_KERNEL_LZ4
74 select HAVE_HW_BREAKPOINT
75 select HAVE_MIXED_BREAKPOINTS_REGS
77 select HAVE_PERF_EVENTS_NMI
79 select HAVE_PERF_USER_STACK_DUMP
80 select HAVE_DEBUG_KMEMLEAK
82 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
83 select HAVE_CMPXCHG_LOCAL
84 select HAVE_CMPXCHG_DOUBLE
85 select HAVE_ARCH_KMEMCHECK
86 select HAVE_USER_RETURN_NOTIFIER
87 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
88 select HAVE_ARCH_JUMP_LABEL
89 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
91 select GENERIC_FIND_FIRST_BIT
92 select GENERIC_IRQ_PROBE
93 select GENERIC_PENDING_IRQ if SMP
94 select GENERIC_IRQ_SHOW
95 select GENERIC_CLOCKEVENTS_MIN_ADJUST
96 select IRQ_FORCED_THREADING
97 select HAVE_BPF_JIT if X86_64
98 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
99 select ARCH_HAS_SG_CHAIN
101 select ARCH_HAVE_NMI_SAFE_CMPXCHG
103 select DCACHE_WORD_ACCESS
104 select GENERIC_SMP_IDLE_THREAD
105 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
106 select HAVE_ARCH_SECCOMP_FILTER
107 select BUILDTIME_EXTABLE_SORT
108 select GENERIC_CMOS_UPDATE
109 select HAVE_ARCH_SOFT_DIRTY if X86_64
110 select CLOCKSOURCE_WATCHDOG
111 select GENERIC_CLOCKEVENTS
112 select ARCH_CLOCKSOURCE_DATA
113 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
114 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
115 select GENERIC_TIME_VSYSCALL
116 select GENERIC_STRNCPY_FROM_USER
117 select GENERIC_STRNLEN_USER
118 select HAVE_CONTEXT_TRACKING if X86_64
119 select HAVE_IRQ_TIME_ACCOUNTING
121 select MODULES_USE_ELF_REL if X86_32
122 select MODULES_USE_ELF_RELA if X86_64
123 select CLONE_BACKWARDS if X86_32
124 select ARCH_USE_BUILTIN_BSWAP
125 select ARCH_USE_QUEUE_RWLOCK
126 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
127 select OLD_SIGACTION if X86_32
128 select COMPAT_OLD_SIGACTION if IA32_EMULATION
130 select HAVE_DEBUG_STACKOVERFLOW
131 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
132 select HAVE_CC_STACKPROTECTOR
133 select GENERIC_CPU_AUTOPROBE
134 select HAVE_ARCH_AUDITSYSCALL
135 select ARCH_SUPPORTS_ATOMIC_RMW
136 select HAVE_ACPI_APEI if ACPI
137 select HAVE_ACPI_APEI_NMI if ACPI
138 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
140 config INSTRUCTION_DECODER
142 depends on KPROBES || PERF_EVENTS || UPROBES
146 default "elf32-i386" if X86_32
147 default "elf64-x86-64" if X86_64
149 config ARCH_DEFCONFIG
151 default "arch/x86/configs/i386_defconfig" if X86_32
152 default "arch/x86/configs/x86_64_defconfig" if X86_64
154 config LOCKDEP_SUPPORT
157 config STACKTRACE_SUPPORT
160 config HAVE_LATENCYTOP_SUPPORT
169 config NEED_DMA_MAP_STATE
171 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
173 config NEED_SG_DMA_LENGTH
176 config GENERIC_ISA_DMA
178 depends on ISA_DMA_API
183 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
185 config GENERIC_BUG_RELATIVE_POINTERS
188 config GENERIC_HWEIGHT
191 config ARCH_MAY_HAVE_PC_FDC
193 depends on ISA_DMA_API
195 config RWSEM_XCHGADD_ALGORITHM
198 config GENERIC_CALIBRATE_DELAY
201 config ARCH_HAS_CPU_RELAX
204 config ARCH_HAS_CACHE_LINE_SIZE
207 config HAVE_SETUP_PER_CPU_AREA
210 config NEED_PER_CPU_EMBED_FIRST_CHUNK
213 config NEED_PER_CPU_PAGE_FIRST_CHUNK
216 config ARCH_HIBERNATION_POSSIBLE
219 config ARCH_SUSPEND_POSSIBLE
222 config ARCH_WANT_HUGE_PMD_SHARE
225 config ARCH_WANT_GENERAL_HUGETLB
236 config ARCH_SUPPORTS_OPTIMIZED_INLINING
239 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
242 config HAVE_INTEL_TXT
244 depends on INTEL_IOMMU && ACPI
248 depends on X86_32 && SMP
252 depends on X86_64 && SMP
258 config X86_32_LAZY_GS
260 depends on X86_32 && !CC_STACKPROTECTOR
262 config ARCH_HWEIGHT_CFLAGS
264 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
265 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
267 config ARCH_SUPPORTS_UPROBES
270 config FIX_EARLYCON_MEM
273 source "init/Kconfig"
274 source "kernel/Kconfig.freezer"
276 menu "Processor type and features"
279 bool "DMA memory allocation support" if EXPERT
282 DMA memory allocation support allows devices with less than 32-bit
283 addressing to allocate within the first 16MB of address space.
284 Disable if no such devices will be used.
289 bool "Symmetric multi-processing support"
291 This enables support for systems with more than one CPU. If you have
292 a system with only one CPU, say N. If you have a system with more
295 If you say N here, the kernel will run on uni- and multiprocessor
296 machines, but will use only one CPU of a multiprocessor machine. If
297 you say Y here, the kernel will run on many, but not all,
298 uniprocessor machines. On a uniprocessor machine, the kernel
299 will run faster if you say N here.
301 Note that if you say Y here and choose architecture "586" or
302 "Pentium" under "Processor family", the kernel will not work on 486
303 architectures. Similarly, multiprocessor kernels for the "PPro"
304 architecture may not work on all Pentium based boards.
306 People using multiprocessor machines who say Y here should also say
307 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
308 Management" code will be disabled if you say Y here.
310 See also <file:Documentation/x86/i386/IO-APIC.txt>,
311 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
312 <http://www.tldp.org/docs.html#howto>.
314 If you don't know what to do here, say N.
317 bool "Support x2apic"
318 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
320 This enables x2apic support on CPUs that have this feature.
322 This allows 32-bit apic IDs (so it can support very large systems),
323 and accesses the local apic via MSRs not via mmio.
325 If you don't know what to do here, say N.
328 bool "Enable MPS table" if ACPI || SFI
330 depends on X86_LOCAL_APIC
332 For old smp systems that do not have proper acpi support. Newer systems
333 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
336 bool "Support for big SMP systems with more than 8 CPUs"
337 depends on X86_32 && SMP
339 This option is needed for the systems that have more than 8 CPUs
343 depends on X86_GOLDFISH
346 config X86_EXTENDED_PLATFORM
347 bool "Support for extended (non-PC) x86 platforms"
350 If you disable this option then the kernel will only support
351 standard PC platforms. (which covers the vast majority of
354 If you enable this option then you'll be able to select support
355 for the following (non-PC) 32 bit x86 platforms:
356 Goldfish (Android emulator)
359 SGI 320/540 (Visual Workstation)
360 STA2X11-based (e.g. Northville)
361 Moorestown MID devices
363 If you have one of these systems, or if you want to build a
364 generic distribution kernel, say Y here - otherwise say N.
368 config X86_EXTENDED_PLATFORM
369 bool "Support for extended (non-PC) x86 platforms"
372 If you disable this option then the kernel will only support
373 standard PC platforms. (which covers the vast majority of
376 If you enable this option then you'll be able to select support
377 for the following (non-PC) 64 bit x86 platforms:
382 If you have one of these systems, or if you want to build a
383 generic distribution kernel, say Y here - otherwise say N.
385 # This is an alphabetically sorted list of 64 bit extended platforms
386 # Please maintain the alphabetic order if and when there are additions
388 bool "Numascale NumaChip"
390 depends on X86_EXTENDED_PLATFORM
393 depends on X86_X2APIC
394 depends on PCI_MMCONFIG
396 Adds support for Numascale NumaChip large-SMP systems. Needed to
397 enable more than ~168 cores.
398 If you don't have one of these, you should say N here.
402 select HYPERVISOR_GUEST
404 depends on X86_64 && PCI
405 depends on X86_EXTENDED_PLATFORM
408 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
409 supposed to run on these EM64T-based machines. Only choose this option
410 if you have one of these machines.
413 bool "SGI Ultraviolet"
415 depends on X86_EXTENDED_PLATFORM
417 depends on X86_X2APIC
419 This option is needed in order to support SGI Ultraviolet systems.
420 If you don't have one of these, you should say N here.
422 # Following is an alphabetically sorted list of 32 bit extended platforms
423 # Please maintain the alphabetic order if and when there are additions
426 bool "Goldfish (Virtual Platform)"
427 depends on X86_EXTENDED_PLATFORM
429 Enable support for the Goldfish virtual platform used primarily
430 for Android development. Unless you are building for the Android
431 Goldfish emulator say N here.
434 bool "CE4100 TV platform"
436 depends on PCI_GODIRECT
438 depends on X86_EXTENDED_PLATFORM
439 select X86_REBOOTFIXUPS
441 select OF_EARLY_FLATTREE
444 Select for the Intel CE media processor (CE4100) SOC.
445 This option compiles in support for the CE4100 SOC for settop
446 boxes and media devices.
449 bool "Intel MID platform support"
451 depends on X86_EXTENDED_PLATFORM
452 depends on X86_PLATFORM_DEVICES
455 depends on X86_IO_APIC
461 select MFD_INTEL_MSIC
463 Select to build a kernel capable of supporting Intel MID (Mobile
464 Internet Device) platform systems which do not have the PCI legacy
465 interfaces. If you are building for a PC class system say N here.
467 Intel MID platforms are based on an Intel processor and chipset which
468 consume less power than most of the x86 derivatives.
470 config X86_INTEL_LPSS
471 bool "Intel Low Power Subsystem Support"
476 Select to build support for Intel Low Power Subsystem such as
477 found on Intel Lynxpoint PCH. Selecting this option enables
478 things like clock tree (common clock framework) and pincontrol
479 which are needed by the LPSS peripheral drivers.
482 bool "RDC R-321x SoC"
484 depends on X86_EXTENDED_PLATFORM
486 select X86_REBOOTFIXUPS
488 This option is needed for RDC R-321x system-on-chip, also known
490 If you don't have one of these chips, you should say N here.
492 config X86_32_NON_STANDARD
493 bool "Support non-standard 32-bit SMP architectures"
494 depends on X86_32 && SMP
495 depends on X86_EXTENDED_PLATFORM
497 This option compiles in the bigsmp and STA2X11 default
498 subarchitectures. It is intended for a generic binary
499 kernel. If you select them all, kernel will probe it one by
500 one and will fallback to default.
502 # Alphabetically sorted list of Non standard 32 bit platforms
504 config X86_SUPPORTS_MEMORY_FAILURE
506 # MCE code calls memory_failure():
508 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
509 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
510 depends on X86_64 || !SPARSEMEM
511 select ARCH_SUPPORTS_MEMORY_FAILURE
514 bool "STA2X11 Companion Chip Support"
515 depends on X86_32_NON_STANDARD && PCI
516 select X86_DEV_DMA_OPS
520 select ARCH_REQUIRE_GPIOLIB
523 This adds support for boards based on the STA2X11 IO-Hub,
524 a.k.a. "ConneXt". The chip is used in place of the standard
525 PC chipset, so all "standard" peripherals are missing. If this
526 option is selected the kernel will still be able to boot on
527 standard PC machines.
530 tristate "Eurobraille/Iris poweroff module"
533 The Iris machines from EuroBraille do not have APM or ACPI support
534 to shut themselves down properly. A special I/O sequence is
535 needed to do so, which is what this module does at
538 This is only for Iris machines from EuroBraille.
542 config SCHED_OMIT_FRAME_POINTER
544 prompt "Single-depth WCHAN output"
547 Calculate simpler /proc/<PID>/wchan values. If this option
548 is disabled then wchan values will recurse back to the
549 caller function. This provides more accurate wchan values,
550 at the expense of slightly more scheduling overhead.
552 If in doubt, say "Y".
554 menuconfig HYPERVISOR_GUEST
555 bool "Linux guest support"
557 Say Y here to enable options for running Linux under various hyper-
558 visors. This option enables basic hypervisor detection and platform
561 If you say N, all options in this submenu will be skipped and
562 disabled, and Linux guest support won't be built in.
567 bool "Enable paravirtualization code"
569 This changes the kernel so it can modify itself when it is run
570 under a hypervisor, potentially improving performance significantly
571 over full virtualization. However, when run without a hypervisor
572 the kernel is theoretically slower and slightly larger.
574 config PARAVIRT_DEBUG
575 bool "paravirt-ops debugging"
576 depends on PARAVIRT && DEBUG_KERNEL
578 Enable to debug paravirt_ops internals. Specifically, BUG if
579 a paravirt_op is missing when it is called.
581 config PARAVIRT_SPINLOCKS
582 bool "Paravirtualization layer for spinlocks"
583 depends on PARAVIRT && SMP
584 select UNINLINE_SPIN_UNLOCK
586 Paravirtualized spinlocks allow a pvops backend to replace the
587 spinlock implementation with something virtualization-friendly
588 (for example, block the virtual CPU rather than spinning).
590 It has a minimal impact on native kernels and gives a nice performance
591 benefit on paravirtualized KVM / Xen kernels.
593 If you are unsure how to answer this question, answer Y.
595 source "arch/x86/xen/Kconfig"
598 bool "KVM Guest support (including kvmclock)"
600 select PARAVIRT_CLOCK
603 This option enables various optimizations for running under the KVM
604 hypervisor. It includes a paravirtualized clock, so that instead
605 of relying on a PIT (or probably other) emulation by the
606 underlying device model, the host provides the guest with
607 timing infrastructure such as time of day, and system time
610 bool "Enable debug information for KVM Guests in debugfs"
611 depends on KVM_GUEST && DEBUG_FS
614 This option enables collection of various statistics for KVM guest.
615 Statistics are displayed in debugfs filesystem. Enabling this option
616 may incur significant overhead.
618 source "arch/x86/lguest/Kconfig"
620 config PARAVIRT_TIME_ACCOUNTING
621 bool "Paravirtual steal time accounting"
625 Select this option to enable fine granularity task steal time
626 accounting. Time spent executing other tasks in parallel with
627 the current vCPU is discounted from the vCPU power. To account for
628 that, there can be a small performance impact.
630 If in doubt, say N here.
632 config PARAVIRT_CLOCK
635 endif #HYPERVISOR_GUEST
643 This option adds a kernel parameter 'memtest', which allows memtest
645 memtest=0, mean disabled; -- default
646 memtest=1, mean do 1 test pattern;
648 memtest=4, mean do 4 test patterns.
649 If you are unsure how to answer this question, answer N.
651 source "arch/x86/Kconfig.cpu"
655 prompt "HPET Timer Support" if X86_32
657 Use the IA-PC HPET (High Precision Event Timer) to manage
658 time in preference to the PIT and RTC, if a HPET is
660 HPET is the next generation timer replacing legacy 8254s.
661 The HPET provides a stable time base on SMP
662 systems, unlike the TSC, but it is more expensive to access,
663 as it is off-chip. You can find the HPET spec at
664 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
666 You can safely choose Y here. However, HPET will only be
667 activated if the platform and the BIOS support this feature.
668 Otherwise the 8254 will be used for timing services.
670 Choose N to continue using the legacy 8254 timer.
672 config HPET_EMULATE_RTC
674 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
677 def_bool y if X86_INTEL_MID
678 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
680 depends on X86_INTEL_MID && SFI
682 APB timer is the replacement for 8254, HPET on X86 MID platforms.
683 The APBT provides a stable time base on SMP
684 systems, unlike the TSC, but it is more expensive to access,
685 as it is off-chip. APB timers are always running regardless of CPU
686 C states, they are used as per CPU clockevent device when possible.
688 # Mark as expert because too many people got it wrong.
689 # The code disables itself when not needed.
692 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
693 bool "Enable DMI scanning" if EXPERT
695 Enabled scanning of DMI to identify machine quirks. Say Y
696 here unless you have verified that your setup is not
697 affected by entries in the DMI blacklist. Required by PNP
701 bool "Old AMD GART IOMMU support"
703 depends on X86_64 && PCI && AMD_NB
705 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
706 GART based hardware IOMMUs.
708 The GART supports full DMA access for devices with 32-bit access
709 limitations, on systems with more than 3 GB. This is usually needed
710 for USB, sound, many IDE/SATA chipsets and some other devices.
712 Newer systems typically have a modern AMD IOMMU, supported via
713 the CONFIG_AMD_IOMMU=y config option.
715 In normal configurations this driver is only active when needed:
716 there's more than 3 GB of memory and the system contains a
717 32-bit limited device.
722 bool "IBM Calgary IOMMU support"
724 depends on X86_64 && PCI
726 Support for hardware IOMMUs in IBM's xSeries x366 and x460
727 systems. Needed to run systems with more than 3GB of memory
728 properly with 32-bit PCI devices that do not support DAC
729 (Double Address Cycle). Calgary also supports bus level
730 isolation, where all DMAs pass through the IOMMU. This
731 prevents them from going anywhere except their intended
732 destination. This catches hard-to-find kernel bugs and
733 mis-behaving drivers and devices that do not use the DMA-API
734 properly to set up their DMA buffers. The IOMMU can be
735 turned off at boot time with the iommu=off parameter.
736 Normally the kernel will make the right choice by itself.
739 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
741 prompt "Should Calgary be enabled by default?"
742 depends on CALGARY_IOMMU
744 Should Calgary be enabled by default? if you choose 'y', Calgary
745 will be used (if it exists). If you choose 'n', Calgary will not be
746 used even if it exists. If you choose 'n' and would like to use
747 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
750 # need this always selected by IOMMU for the VIA workaround
754 Support for software bounce buffers used on x86-64 systems
755 which don't have a hardware IOMMU. Using this PCI devices
756 which can only access 32-bits of memory can be used on systems
757 with more than 3 GB of memory.
762 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
765 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
766 depends on X86_64 && SMP && DEBUG_KERNEL
767 select CPUMASK_OFFSTACK
769 Enable maximum number of CPUS and NUMA Nodes for this architecture.
773 int "Maximum number of CPUs" if SMP && !MAXSMP
774 range 2 8 if SMP && X86_32 && !X86_BIGSMP
775 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
776 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
778 default "8192" if MAXSMP
779 default "32" if SMP && X86_BIGSMP
782 This allows you to specify the maximum number of CPUs which this
783 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
784 supported value is 4096, otherwise the maximum value is 512. The
785 minimum value which makes sense is 2.
787 This is purely to save memory - each supported CPU adds
788 approximately eight kilobytes to the kernel image.
791 bool "SMT (Hyperthreading) scheduler support"
794 SMT scheduler support improves the CPU scheduler's decision making
795 when dealing with Intel Pentium 4 chips with HyperThreading at a
796 cost of slightly increased overhead in some places. If unsure say
801 prompt "Multi-core scheduler support"
804 Multi-core scheduler support improves the CPU scheduler's decision
805 making when dealing with multi-core CPU chips at a cost of slightly
806 increased overhead in some places. If unsure say N here.
808 source "kernel/Kconfig.preempt"
811 bool "Local APIC support on uniprocessors"
812 depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI
814 A local APIC (Advanced Programmable Interrupt Controller) is an
815 integrated interrupt controller in the CPU. If you have a single-CPU
816 system which has a processor with a local APIC, you can say Y here to
817 enable and use it. If you say Y here even though your machine doesn't
818 have a local APIC, then the kernel will still run with no slowdown at
819 all. The local APIC supports CPU-generated self-interrupts (timer,
820 performance counters), and the NMI watchdog which detects hard
824 bool "IO-APIC support on uniprocessors"
825 depends on X86_UP_APIC
827 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
828 SMP-capable replacement for PC-style interrupt controllers. Most
829 SMP systems and many recent uniprocessor systems have one.
831 If you have a single-CPU system with an IO-APIC, you can say Y here
832 to use it. If you say Y here even though your machine doesn't have
833 an IO-APIC, then the kernel will still run with no slowdown at all.
835 config X86_LOCAL_APIC
837 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
841 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
842 select GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
844 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
845 bool "Reroute for broken boot IRQs"
846 depends on X86_IO_APIC
848 This option enables a workaround that fixes a source of
849 spurious interrupts. This is recommended when threaded
850 interrupt handling is used on systems where the generation of
851 superfluous "boot interrupts" cannot be disabled.
853 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
854 entry in the chipset's IO-APIC is masked (as, e.g. the RT
855 kernel does during interrupt handling). On chipsets where this
856 boot IRQ generation cannot be disabled, this workaround keeps
857 the original IRQ line masked so that only the equivalent "boot
858 IRQ" is delivered to the CPUs. The workaround also tells the
859 kernel to set up the IRQ handler on the boot IRQ line. In this
860 way only one interrupt is delivered to the kernel. Otherwise
861 the spurious second interrupt may cause the kernel to bring
862 down (vital) interrupt lines.
864 Only affects "broken" chipsets. Interrupt sharing may be
865 increased on these systems.
868 bool "Machine Check / overheating reporting"
871 Machine Check support allows the processor to notify the
872 kernel if it detects a problem (e.g. overheating, data corruption).
873 The action the kernel takes depends on the severity of the problem,
874 ranging from warning messages to halting the machine.
878 prompt "Intel MCE features"
879 depends on X86_MCE && X86_LOCAL_APIC
881 Additional support for intel specific MCE features such as
886 prompt "AMD MCE features"
887 depends on X86_MCE && X86_LOCAL_APIC
889 Additional support for AMD specific MCE features such as
890 the DRAM Error Threshold.
892 config X86_ANCIENT_MCE
893 bool "Support for old Pentium 5 / WinChip machine checks"
894 depends on X86_32 && X86_MCE
896 Include support for machine check handling on old Pentium 5 or WinChip
897 systems. These typically need to be enabled explicitly on the command
900 config X86_MCE_THRESHOLD
901 depends on X86_MCE_AMD || X86_MCE_INTEL
904 config X86_MCE_INJECT
906 tristate "Machine check injector support"
908 Provide support for injecting machine checks for testing purposes.
909 If you don't know what a machine check is and you don't do kernel
910 QA it is safe to say n.
912 config X86_THERMAL_VECTOR
914 depends on X86_MCE_INTEL
917 bool "Enable VM86 support" if EXPERT
921 This option is required by programs like DOSEMU to run
922 16-bit real mode legacy code on x86 processors. It also may
923 be needed by software like XFree86 to initialize some video
924 cards via BIOS. Disabling this option saves about 6K.
927 bool "Enable support for 16-bit segments" if EXPERT
930 This option is required by programs like Wine to run 16-bit
931 protected mode legacy code on x86 processors. Disabling
932 this option saves about 300 bytes on i386, or around 6K text
933 plus 16K runtime memory on x86-64,
937 depends on X86_16BIT && X86_32
941 depends on X86_16BIT && X86_64
944 tristate "Toshiba Laptop support"
947 This adds a driver to safely access the System Management Mode of
948 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
949 not work on models with a Phoenix BIOS. The System Management Mode
950 is used to set the BIOS and power saving options on Toshiba portables.
952 For information on utilities to make use of this driver see the
953 Toshiba Linux utilities web site at:
954 <http://www.buzzard.org.uk/toshiba/>.
956 Say Y if you intend to run this kernel on a Toshiba portable.
960 tristate "Dell laptop support"
963 This adds a driver to safely access the System Management Mode
964 of the CPU on the Dell Inspiron 8000. The System Management Mode
965 is used to read cpu temperature and cooling fan status and to
966 control the fans on the I8K portables.
968 This driver has been tested only on the Inspiron 8000 but it may
969 also work with other Dell laptops. You can force loading on other
970 models by passing the parameter `force=1' to the module. Use at
973 For information on utilities to make use of this driver see the
974 I8K Linux utilities web site at:
975 <http://people.debian.org/~dz/i8k/>
977 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
980 config X86_REBOOTFIXUPS
981 bool "Enable X86 board specific fixups for reboot"
984 This enables chipset and/or board specific fixups to be done
985 in order to get reboot to work correctly. This is only needed on
986 some combinations of hardware and BIOS. The symptom, for which
987 this config is intended, is when reboot ends with a stalled/hung
990 Currently, the only fixup is for the Geode machines using
991 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
993 Say Y if you want to enable the fixup. Currently, it's safe to
994 enable this option even if you don't need it.
998 tristate "CPU microcode loading support"
999 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1003 If you say Y here, you will be able to update the microcode on
1004 certain Intel and AMD processors. The Intel support is for the
1005 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1006 Xeon etc. The AMD support is for families 0x10 and later. You will
1007 obviously need the actual microcode binary data itself which is not
1008 shipped with the Linux kernel.
1010 This option selects the general module only, you need to select
1011 at least one vendor specific module as well.
1013 To compile this driver as a module, choose M here: the module
1014 will be called microcode.
1016 config MICROCODE_INTEL
1017 bool "Intel microcode loading support"
1018 depends on MICROCODE
1022 This options enables microcode patch loading support for Intel
1025 For the current Intel microcode data package go to
1026 <https://downloadcenter.intel.com> and search for
1027 'Linux Processor Microcode Data File'.
1029 config MICROCODE_AMD
1030 bool "AMD microcode loading support"
1031 depends on MICROCODE
1034 If you select this option, microcode patch loading support for AMD
1035 processors will be enabled.
1037 config MICROCODE_OLD_INTERFACE
1039 depends on MICROCODE
1041 config MICROCODE_INTEL_EARLY
1044 config MICROCODE_AMD_EARLY
1047 config MICROCODE_EARLY
1048 bool "Early load microcode"
1049 depends on MICROCODE=y && BLK_DEV_INITRD
1050 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1051 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1054 This option provides functionality to read additional microcode data
1055 at the beginning of initrd image. The data tells kernel to load
1056 microcode to CPU's as early as possible. No functional change if no
1057 microcode data is glued to the initrd, therefore it's safe to say Y.
1060 tristate "/dev/cpu/*/msr - Model-specific register support"
1062 This device gives privileged processes access to the x86
1063 Model-Specific Registers (MSRs). It is a character device with
1064 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1065 MSR accesses are directed to a specific CPU on multi-processor
1069 tristate "/dev/cpu/*/cpuid - CPU information support"
1071 This device gives processes access to the x86 CPUID instruction to
1072 be executed on a specific processor. It is a character device
1073 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1077 prompt "High Memory Support"
1084 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1085 However, the address space of 32-bit x86 processors is only 4
1086 Gigabytes large. That means that, if you have a large amount of
1087 physical memory, not all of it can be "permanently mapped" by the
1088 kernel. The physical memory that's not permanently mapped is called
1091 If you are compiling a kernel which will never run on a machine with
1092 more than 1 Gigabyte total physical RAM, answer "off" here (default
1093 choice and suitable for most users). This will result in a "3GB/1GB"
1094 split: 3GB are mapped so that each process sees a 3GB virtual memory
1095 space and the remaining part of the 4GB virtual memory space is used
1096 by the kernel to permanently map as much physical memory as
1099 If the machine has between 1 and 4 Gigabytes physical RAM, then
1102 If more than 4 Gigabytes is used then answer "64GB" here. This
1103 selection turns Intel PAE (Physical Address Extension) mode on.
1104 PAE implements 3-level paging on IA32 processors. PAE is fully
1105 supported by Linux, PAE mode is implemented on all recent Intel
1106 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1107 then the kernel will not boot on CPUs that don't support PAE!
1109 The actual amount of total physical memory will either be
1110 auto detected or can be forced by using a kernel command line option
1111 such as "mem=256M". (Try "man bootparam" or see the documentation of
1112 your boot loader (lilo or loadlin) about how to pass options to the
1113 kernel at boot time.)
1115 If unsure, say "off".
1120 Select this if you have a 32-bit processor and between 1 and 4
1121 gigabytes of physical RAM.
1128 Select this if you have a 32-bit processor and more than 4
1129 gigabytes of physical RAM.
1134 prompt "Memory split" if EXPERT
1138 Select the desired split between kernel and user memory.
1140 If the address range available to the kernel is less than the
1141 physical memory installed, the remaining memory will be available
1142 as "high memory". Accessing high memory is a little more costly
1143 than low memory, as it needs to be mapped into the kernel first.
1144 Note that increasing the kernel address space limits the range
1145 available to user programs, making the address space there
1146 tighter. Selecting anything other than the default 3G/1G split
1147 will also likely make your kernel incompatible with binary-only
1150 If you are not absolutely sure what you are doing, leave this
1154 bool "3G/1G user/kernel split"
1155 config VMSPLIT_3G_OPT
1157 bool "3G/1G user/kernel split (for full 1G low memory)"
1159 bool "2G/2G user/kernel split"
1160 config VMSPLIT_2G_OPT
1162 bool "2G/2G user/kernel split (for full 2G low memory)"
1164 bool "1G/3G user/kernel split"
1169 default 0xB0000000 if VMSPLIT_3G_OPT
1170 default 0x80000000 if VMSPLIT_2G
1171 default 0x78000000 if VMSPLIT_2G_OPT
1172 default 0x40000000 if VMSPLIT_1G
1178 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1181 bool "PAE (Physical Address Extension) Support"
1182 depends on X86_32 && !HIGHMEM4G
1184 PAE is required for NX support, and furthermore enables
1185 larger swapspace support for non-overcommit purposes. It
1186 has the cost of more pagetable lookup overhead, and also
1187 consumes more pagetable space per process.
1189 config ARCH_PHYS_ADDR_T_64BIT
1191 depends on X86_64 || X86_PAE
1193 config ARCH_DMA_ADDR_T_64BIT
1195 depends on X86_64 || HIGHMEM64G
1197 config DIRECT_GBPAGES
1198 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1202 Allow the kernel linear mapping to use 1GB pages on CPUs that
1203 support it. This can improve the kernel's performance a tiny bit by
1204 reducing TLB pressure. If in doubt, say "Y".
1206 # Common NUMA Features
1208 bool "Numa Memory Allocation and Scheduler Support"
1210 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1211 default y if X86_BIGSMP
1213 Enable NUMA (Non Uniform Memory Access) support.
1215 The kernel will try to allocate memory used by a CPU on the
1216 local memory controller of the CPU and add some more
1217 NUMA awareness to the kernel.
1219 For 64-bit this is recommended if the system is Intel Core i7
1220 (or later), AMD Opteron, or EM64T NUMA.
1222 For 32-bit this is only needed if you boot a 32-bit
1223 kernel on a 64-bit NUMA platform.
1225 Otherwise, you should say N.
1229 prompt "Old style AMD Opteron NUMA detection"
1230 depends on X86_64 && NUMA && PCI
1232 Enable AMD NUMA node topology detection. You should say Y here if
1233 you have a multi processor AMD system. This uses an old method to
1234 read the NUMA configuration directly from the builtin Northbridge
1235 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1236 which also takes priority if both are compiled in.
1238 config X86_64_ACPI_NUMA
1240 prompt "ACPI NUMA detection"
1241 depends on X86_64 && NUMA && ACPI && PCI
1244 Enable ACPI SRAT based node topology detection.
1246 # Some NUMA nodes have memory ranges that span
1247 # other nodes. Even though a pfn is valid and
1248 # between a node's start and end pfns, it may not
1249 # reside on that node. See memmap_init_zone()
1251 config NODES_SPAN_OTHER_NODES
1253 depends on X86_64_ACPI_NUMA
1256 bool "NUMA emulation"
1259 Enable NUMA emulation. A flat machine will be split
1260 into virtual nodes when booted with "numa=fake=N", where N is the
1261 number of nodes. This is only useful for debugging.
1264 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1266 default "10" if MAXSMP
1267 default "6" if X86_64
1269 depends on NEED_MULTIPLE_NODES
1271 Specify the maximum number of NUMA Nodes available on the target
1272 system. Increases memory reserved to accommodate various tables.
1274 config ARCH_HAVE_MEMORY_PRESENT
1276 depends on X86_32 && DISCONTIGMEM
1278 config NEED_NODE_MEMMAP_SIZE
1280 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1282 config ARCH_FLATMEM_ENABLE
1284 depends on X86_32 && !NUMA
1286 config ARCH_DISCONTIGMEM_ENABLE
1288 depends on NUMA && X86_32
1290 config ARCH_DISCONTIGMEM_DEFAULT
1292 depends on NUMA && X86_32
1294 config ARCH_SPARSEMEM_ENABLE
1296 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1297 select SPARSEMEM_STATIC if X86_32
1298 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1300 config ARCH_SPARSEMEM_DEFAULT
1304 config ARCH_SELECT_MEMORY_MODEL
1306 depends on ARCH_SPARSEMEM_ENABLE
1308 config ARCH_MEMORY_PROBE
1309 bool "Enable sysfs memory/probe interface"
1310 depends on X86_64 && MEMORY_HOTPLUG
1312 This option enables a sysfs memory/probe interface for testing.
1313 See Documentation/memory-hotplug.txt for more information.
1314 If you are unsure how to answer this question, answer N.
1316 config ARCH_PROC_KCORE_TEXT
1318 depends on X86_64 && PROC_KCORE
1320 config ILLEGAL_POINTER_VALUE
1323 default 0xdead000000000000 if X86_64
1328 bool "Allocate 3rd-level pagetables from highmem"
1331 The VM uses one page table entry for each page of physical memory.
1332 For systems with a lot of RAM, this can be wasteful of precious
1333 low memory. Setting this option will put user-space page table
1334 entries in high memory.
1336 config X86_CHECK_BIOS_CORRUPTION
1337 bool "Check for low memory corruption"
1339 Periodically check for memory corruption in low memory, which
1340 is suspected to be caused by BIOS. Even when enabled in the
1341 configuration, it is disabled at runtime. Enable it by
1342 setting "memory_corruption_check=1" on the kernel command
1343 line. By default it scans the low 64k of memory every 60
1344 seconds; see the memory_corruption_check_size and
1345 memory_corruption_check_period parameters in
1346 Documentation/kernel-parameters.txt to adjust this.
1348 When enabled with the default parameters, this option has
1349 almost no overhead, as it reserves a relatively small amount
1350 of memory and scans it infrequently. It both detects corruption
1351 and prevents it from affecting the running system.
1353 It is, however, intended as a diagnostic tool; if repeatable
1354 BIOS-originated corruption always affects the same memory,
1355 you can use memmap= to prevent the kernel from using that
1358 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1359 bool "Set the default setting of memory_corruption_check"
1360 depends on X86_CHECK_BIOS_CORRUPTION
1363 Set whether the default state of memory_corruption_check is
1366 config X86_RESERVE_LOW
1367 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1371 Specify the amount of low memory to reserve for the BIOS.
1373 The first page contains BIOS data structures that the kernel
1374 must not use, so that page must always be reserved.
1376 By default we reserve the first 64K of physical RAM, as a
1377 number of BIOSes are known to corrupt that memory range
1378 during events such as suspend/resume or monitor cable
1379 insertion, so it must not be used by the kernel.
1381 You can set this to 4 if you are absolutely sure that you
1382 trust the BIOS to get all its memory reservations and usages
1383 right. If you know your BIOS have problems beyond the
1384 default 64K area, you can set this to 640 to avoid using the
1385 entire low memory range.
1387 If you have doubts about the BIOS (e.g. suspend/resume does
1388 not work or there's kernel crashes after certain hardware
1389 hotplug events) then you might want to enable
1390 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1391 typical corruption patterns.
1393 Leave this to the default value of 64 if you are unsure.
1395 config MATH_EMULATION
1397 prompt "Math emulation" if X86_32
1399 Linux can emulate a math coprocessor (used for floating point
1400 operations) if you don't have one. 486DX and Pentium processors have
1401 a math coprocessor built in, 486SX and 386 do not, unless you added
1402 a 487DX or 387, respectively. (The messages during boot time can
1403 give you some hints here ["man dmesg"].) Everyone needs either a
1404 coprocessor or this emulation.
1406 If you don't have a math coprocessor, you need to say Y here; if you
1407 say Y here even though you have a coprocessor, the coprocessor will
1408 be used nevertheless. (This behavior can be changed with the kernel
1409 command line option "no387", which comes handy if your coprocessor
1410 is broken. Try "man bootparam" or see the documentation of your boot
1411 loader (lilo or loadlin) about how to pass options to the kernel at
1412 boot time.) This means that it is a good idea to say Y here if you
1413 intend to use this kernel on different machines.
1415 More information about the internals of the Linux math coprocessor
1416 emulation can be found in <file:arch/x86/math-emu/README>.
1418 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1419 kernel, it won't hurt.
1423 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1425 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1426 the Memory Type Range Registers (MTRRs) may be used to control
1427 processor access to memory ranges. This is most useful if you have
1428 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1429 allows bus write transfers to be combined into a larger transfer
1430 before bursting over the PCI/AGP bus. This can increase performance
1431 of image write operations 2.5 times or more. Saying Y here creates a
1432 /proc/mtrr file which may be used to manipulate your processor's
1433 MTRRs. Typically the X server should use this.
1435 This code has a reasonably generic interface so that similar
1436 control registers on other processors can be easily supported
1439 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1440 Registers (ARRs) which provide a similar functionality to MTRRs. For
1441 these, the ARRs are used to emulate the MTRRs.
1442 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1443 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1444 write-combining. All of these processors are supported by this code
1445 and it makes sense to say Y here if you have one of them.
1447 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1448 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1449 can lead to all sorts of problems, so it's good to say Y here.
1451 You can safely say Y even if your machine doesn't have MTRRs, you'll
1452 just add about 9 KB to your kernel.
1454 See <file:Documentation/x86/mtrr.txt> for more information.
1456 config MTRR_SANITIZER
1458 prompt "MTRR cleanup support"
1461 Convert MTRR layout from continuous to discrete, so X drivers can
1462 add writeback entries.
1464 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1465 The largest mtrr entry size for a continuous block can be set with
1470 config MTRR_SANITIZER_ENABLE_DEFAULT
1471 int "MTRR cleanup enable value (0-1)"
1474 depends on MTRR_SANITIZER
1476 Enable mtrr cleanup default value
1478 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1479 int "MTRR cleanup spare reg num (0-7)"
1482 depends on MTRR_SANITIZER
1484 mtrr cleanup spare entries default, it can be changed via
1485 mtrr_spare_reg_nr=N on the kernel command line.
1489 prompt "x86 PAT support" if EXPERT
1492 Use PAT attributes to setup page level cache control.
1494 PATs are the modern equivalents of MTRRs and are much more
1495 flexible than MTRRs.
1497 Say N here if you see bootup problems (boot crash, boot hang,
1498 spontaneous reboots) or a non-working video driver.
1502 config ARCH_USES_PG_UNCACHED
1508 prompt "x86 architectural random number generator" if EXPERT
1510 Enable the x86 architectural RDRAND instruction
1511 (Intel Bull Mountain technology) to generate random numbers.
1512 If supported, this is a high bandwidth, cryptographically
1513 secure hardware random number generator.
1517 prompt "Supervisor Mode Access Prevention" if EXPERT
1519 Supervisor Mode Access Prevention (SMAP) is a security
1520 feature in newer Intel processors. There is a small
1521 performance cost if this enabled and turned on; there is
1522 also a small increase in the kernel size if this is enabled.
1527 bool "EFI runtime service support"
1530 select EFI_RUNTIME_WRAPPERS
1532 This enables the kernel to use EFI runtime services that are
1533 available (such as the EFI variable services).
1535 This option is only useful on systems that have EFI firmware.
1536 In addition, you should use the latest ELILO loader available
1537 at <http://elilo.sourceforge.net> in order to take advantage
1538 of EFI runtime services. However, even with this option, the
1539 resultant kernel should continue to boot on existing non-EFI
1543 bool "EFI stub support"
1546 This kernel feature allows a bzImage to be loaded directly
1547 by EFI firmware without the use of a bootloader.
1549 See Documentation/efi-stub.txt for more information.
1552 bool "EFI mixed-mode support"
1553 depends on EFI_STUB && X86_64
1555 Enabling this feature allows a 64-bit kernel to be booted
1556 on a 32-bit firmware, provided that your CPU supports 64-bit
1559 Note that it is not possible to boot a mixed-mode enabled
1560 kernel via the EFI boot stub - a bootloader that supports
1561 the EFI handover protocol must be used.
1567 prompt "Enable seccomp to safely compute untrusted bytecode"
1569 This kernel feature is useful for number crunching applications
1570 that may need to compute untrusted bytecode during their
1571 execution. By using pipes or other transports made available to
1572 the process as file descriptors supporting the read/write
1573 syscalls, it's possible to isolate those applications in
1574 their own address space using seccomp. Once seccomp is
1575 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1576 and the task is only allowed to execute a few safe syscalls
1577 defined by each seccomp mode.
1579 If unsure, say Y. Only embedded should say N here.
1581 source kernel/Kconfig.hz
1584 bool "kexec system call"
1587 select CRYPTO_SHA256
1589 kexec is a system call that implements the ability to shutdown your
1590 current kernel, and to start another kernel. It is like a reboot
1591 but it is independent of the system firmware. And like a reboot
1592 you can start any kernel with it, not just Linux.
1594 The name comes from the similarity to the exec system call.
1596 It is an ongoing process to be certain the hardware in a machine
1597 is properly shutdown, so do not be surprised if this code does not
1598 initially work for you. As of this writing the exact hardware
1599 interface is strongly in flux, so no good recommendation can be
1602 config KEXEC_VERIFY_SIG
1603 bool "Verify kernel signature during kexec_file_load() syscall"
1606 This option makes kernel signature verification mandatory for
1607 kexec_file_load() syscall. If kernel is signature can not be
1608 verified, kexec_file_load() will fail.
1610 This option enforces signature verification at generic level.
1611 One needs to enable signature verification for type of kernel
1612 image being loaded to make sure it works. For example, enable
1613 bzImage signature verification option to be able to load and
1614 verify signatures of bzImage. Otherwise kernel loading will fail.
1616 config KEXEC_BZIMAGE_VERIFY_SIG
1617 bool "Enable bzImage signature verification support"
1618 depends on KEXEC_VERIFY_SIG
1619 depends on SIGNED_PE_FILE_VERIFICATION
1620 select SYSTEM_TRUSTED_KEYRING
1622 Enable bzImage signature verification support.
1625 bool "kernel crash dumps"
1626 depends on X86_64 || (X86_32 && HIGHMEM)
1628 Generate crash dump after being started by kexec.
1629 This should be normally only set in special crash dump kernels
1630 which are loaded in the main kernel with kexec-tools into
1631 a specially reserved region and then later executed after
1632 a crash by kdump/kexec. The crash dump kernel must be compiled
1633 to a memory address not used by the main kernel or BIOS using
1634 PHYSICAL_START, or it must be built as a relocatable image
1635 (CONFIG_RELOCATABLE=y).
1636 For more details see Documentation/kdump/kdump.txt
1640 depends on KEXEC && HIBERNATION
1642 Jump between original kernel and kexeced kernel and invoke
1643 code in physical address mode via KEXEC
1645 config PHYSICAL_START
1646 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1649 This gives the physical address where the kernel is loaded.
1651 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1652 bzImage will decompress itself to above physical address and
1653 run from there. Otherwise, bzImage will run from the address where
1654 it has been loaded by the boot loader and will ignore above physical
1657 In normal kdump cases one does not have to set/change this option
1658 as now bzImage can be compiled as a completely relocatable image
1659 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1660 address. This option is mainly useful for the folks who don't want
1661 to use a bzImage for capturing the crash dump and want to use a
1662 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1663 to be specifically compiled to run from a specific memory area
1664 (normally a reserved region) and this option comes handy.
1666 So if you are using bzImage for capturing the crash dump,
1667 leave the value here unchanged to 0x1000000 and set
1668 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1669 for capturing the crash dump change this value to start of
1670 the reserved region. In other words, it can be set based on
1671 the "X" value as specified in the "crashkernel=YM@XM"
1672 command line boot parameter passed to the panic-ed
1673 kernel. Please take a look at Documentation/kdump/kdump.txt
1674 for more details about crash dumps.
1676 Usage of bzImage for capturing the crash dump is recommended as
1677 one does not have to build two kernels. Same kernel can be used
1678 as production kernel and capture kernel. Above option should have
1679 gone away after relocatable bzImage support is introduced. But it
1680 is present because there are users out there who continue to use
1681 vmlinux for dump capture. This option should go away down the
1684 Don't change this unless you know what you are doing.
1687 bool "Build a relocatable kernel"
1690 This builds a kernel image that retains relocation information
1691 so it can be loaded someplace besides the default 1MB.
1692 The relocations tend to make the kernel binary about 10% larger,
1693 but are discarded at runtime.
1695 One use is for the kexec on panic case where the recovery kernel
1696 must live at a different physical address than the primary
1699 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1700 it has been loaded at and the compile time physical address
1701 (CONFIG_PHYSICAL_START) is used as the minimum location.
1703 config RANDOMIZE_BASE
1704 bool "Randomize the address of the kernel image"
1705 depends on RELOCATABLE
1708 Randomizes the physical and virtual address at which the
1709 kernel image is decompressed, as a security feature that
1710 deters exploit attempts relying on knowledge of the location
1711 of kernel internals.
1713 Entropy is generated using the RDRAND instruction if it is
1714 supported. If RDTSC is supported, it is used as well. If
1715 neither RDRAND nor RDTSC are supported, then randomness is
1716 read from the i8254 timer.
1718 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1719 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1720 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1721 minimum of 2MiB, only 10 bits of entropy is theoretically
1722 possible. At best, due to page table layouts, 64-bit can use
1723 9 bits of entropy and 32-bit uses 8 bits.
1727 config RANDOMIZE_BASE_MAX_OFFSET
1728 hex "Maximum kASLR offset allowed" if EXPERT
1729 depends on RANDOMIZE_BASE
1730 range 0x0 0x20000000 if X86_32
1731 default "0x20000000" if X86_32
1732 range 0x0 0x40000000 if X86_64
1733 default "0x40000000" if X86_64
1735 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1736 memory is used to determine the maximal offset in bytes that will
1737 be applied to the kernel when kernel Address Space Layout
1738 Randomization (kASLR) is active. This must be a multiple of
1741 On 32-bit this is limited to 512MiB by page table layouts. The
1744 On 64-bit this is limited by how the kernel fixmap page table is
1745 positioned, so this cannot be larger than 1GiB currently. Without
1746 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1747 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1748 modules area will shrink to compensate, up to the current maximum
1749 1GiB to 1GiB split. The default is 1GiB.
1751 If unsure, leave at the default value.
1753 # Relocation on x86 needs some additional build support
1754 config X86_NEED_RELOCS
1756 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1758 config PHYSICAL_ALIGN
1759 hex "Alignment value to which kernel should be aligned"
1761 range 0x2000 0x1000000 if X86_32
1762 range 0x200000 0x1000000 if X86_64
1764 This value puts the alignment restrictions on physical address
1765 where kernel is loaded and run from. Kernel is compiled for an
1766 address which meets above alignment restriction.
1768 If bootloader loads the kernel at a non-aligned address and
1769 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1770 address aligned to above value and run from there.
1772 If bootloader loads the kernel at a non-aligned address and
1773 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1774 load address and decompress itself to the address it has been
1775 compiled for and run from there. The address for which kernel is
1776 compiled already meets above alignment restrictions. Hence the
1777 end result is that kernel runs from a physical address meeting
1778 above alignment restrictions.
1780 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1781 this value must be a multiple of 0x200000.
1783 Don't change this unless you know what you are doing.
1786 bool "Support for hot-pluggable CPUs"
1789 Say Y here to allow turning CPUs off and on. CPUs can be
1790 controlled through /sys/devices/system/cpu.
1791 ( Note: power management support will enable this option
1792 automatically on SMP systems. )
1793 Say N if you want to disable CPU hotplug.
1795 config BOOTPARAM_HOTPLUG_CPU0
1796 bool "Set default setting of cpu0_hotpluggable"
1798 depends on HOTPLUG_CPU
1800 Set whether default state of cpu0_hotpluggable is on or off.
1802 Say Y here to enable CPU0 hotplug by default. If this switch
1803 is turned on, there is no need to give cpu0_hotplug kernel
1804 parameter and the CPU0 hotplug feature is enabled by default.
1806 Please note: there are two known CPU0 dependencies if you want
1807 to enable the CPU0 hotplug feature either by this switch or by
1808 cpu0_hotplug kernel parameter.
1810 First, resume from hibernate or suspend always starts from CPU0.
1811 So hibernate and suspend are prevented if CPU0 is offline.
1813 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1814 offline if any interrupt can not migrate out of CPU0. There may
1815 be other CPU0 dependencies.
1817 Please make sure the dependencies are under your control before
1818 you enable this feature.
1820 Say N if you don't want to enable CPU0 hotplug feature by default.
1821 You still can enable the CPU0 hotplug feature at boot by kernel
1822 parameter cpu0_hotplug.
1824 config DEBUG_HOTPLUG_CPU0
1826 prompt "Debug CPU0 hotplug"
1827 depends on HOTPLUG_CPU
1829 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1830 soon as possible and boots up userspace with CPU0 offlined. User
1831 can online CPU0 back after boot time.
1833 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1834 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1835 compilation or giving cpu0_hotplug kernel parameter at boot.
1841 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
1842 depends on X86_32 || IA32_EMULATION
1844 Certain buggy versions of glibc will crash if they are
1845 presented with a 32-bit vDSO that is not mapped at the address
1846 indicated in its segment table.
1848 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
1849 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
1850 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
1851 the only released version with the bug, but OpenSUSE 9
1852 contains a buggy "glibc 2.3.2".
1854 The symptom of the bug is that everything crashes on startup, saying:
1855 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
1857 Saying Y here changes the default value of the vdso32 boot
1858 option from 1 to 0, which turns off the 32-bit vDSO entirely.
1859 This works around the glibc bug but hurts performance.
1861 If unsure, say N: if you are compiling your own kernel, you
1862 are unlikely to be using a buggy version of glibc.
1865 bool "Built-in kernel command line"
1867 Allow for specifying boot arguments to the kernel at
1868 build time. On some systems (e.g. embedded ones), it is
1869 necessary or convenient to provide some or all of the
1870 kernel boot arguments with the kernel itself (that is,
1871 to not rely on the boot loader to provide them.)
1873 To compile command line arguments into the kernel,
1874 set this option to 'Y', then fill in the
1875 the boot arguments in CONFIG_CMDLINE.
1877 Systems with fully functional boot loaders (i.e. non-embedded)
1878 should leave this option set to 'N'.
1881 string "Built-in kernel command string"
1882 depends on CMDLINE_BOOL
1885 Enter arguments here that should be compiled into the kernel
1886 image and used at boot time. If the boot loader provides a
1887 command line at boot time, it is appended to this string to
1888 form the full kernel command line, when the system boots.
1890 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1891 change this behavior.
1893 In most cases, the command line (whether built-in or provided
1894 by the boot loader) should specify the device for the root
1897 config CMDLINE_OVERRIDE
1898 bool "Built-in command line overrides boot loader arguments"
1899 depends on CMDLINE_BOOL
1901 Set this option to 'Y' to have the kernel ignore the boot loader
1902 command line, and use ONLY the built-in command line.
1904 This is used to work around broken boot loaders. This should
1905 be set to 'N' under normal conditions.
1909 config ARCH_ENABLE_MEMORY_HOTPLUG
1911 depends on X86_64 || (X86_32 && HIGHMEM)
1913 config ARCH_ENABLE_MEMORY_HOTREMOVE
1915 depends on MEMORY_HOTPLUG
1917 config USE_PERCPU_NUMA_NODE_ID
1921 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1923 depends on X86_64 || X86_PAE
1925 config ARCH_ENABLE_HUGEPAGE_MIGRATION
1927 depends on X86_64 && HUGETLB_PAGE && MIGRATION
1929 menu "Power management and ACPI options"
1931 config ARCH_HIBERNATION_HEADER
1933 depends on X86_64 && HIBERNATION
1935 source "kernel/power/Kconfig"
1937 source "drivers/acpi/Kconfig"
1939 source "drivers/sfi/Kconfig"
1946 tristate "APM (Advanced Power Management) BIOS support"
1947 depends on X86_32 && PM_SLEEP
1949 APM is a BIOS specification for saving power using several different
1950 techniques. This is mostly useful for battery powered laptops with
1951 APM compliant BIOSes. If you say Y here, the system time will be
1952 reset after a RESUME operation, the /proc/apm device will provide
1953 battery status information, and user-space programs will receive
1954 notification of APM "events" (e.g. battery status change).
1956 If you select "Y" here, you can disable actual use of the APM
1957 BIOS by passing the "apm=off" option to the kernel at boot time.
1959 Note that the APM support is almost completely disabled for
1960 machines with more than one CPU.
1962 In order to use APM, you will need supporting software. For location
1963 and more information, read <file:Documentation/power/apm-acpi.txt>
1964 and the Battery Powered Linux mini-HOWTO, available from
1965 <http://www.tldp.org/docs.html#howto>.
1967 This driver does not spin down disk drives (see the hdparm(8)
1968 manpage ("man 8 hdparm") for that), and it doesn't turn off
1969 VESA-compliant "green" monitors.
1971 This driver does not support the TI 4000M TravelMate and the ACER
1972 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1973 desktop machines also don't have compliant BIOSes, and this driver
1974 may cause those machines to panic during the boot phase.
1976 Generally, if you don't have a battery in your machine, there isn't
1977 much point in using this driver and you should say N. If you get
1978 random kernel OOPSes or reboots that don't seem to be related to
1979 anything, try disabling/enabling this option (or disabling/enabling
1982 Some other things you should try when experiencing seemingly random,
1985 1) make sure that you have enough swap space and that it is
1987 2) pass the "no-hlt" option to the kernel
1988 3) switch on floating point emulation in the kernel and pass
1989 the "no387" option to the kernel
1990 4) pass the "floppy=nodma" option to the kernel
1991 5) pass the "mem=4M" option to the kernel (thereby disabling
1992 all but the first 4 MB of RAM)
1993 6) make sure that the CPU is not over clocked.
1994 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1995 8) disable the cache from your BIOS settings
1996 9) install a fan for the video card or exchange video RAM
1997 10) install a better fan for the CPU
1998 11) exchange RAM chips
1999 12) exchange the motherboard.
2001 To compile this driver as a module, choose M here: the
2002 module will be called apm.
2006 config APM_IGNORE_USER_SUSPEND
2007 bool "Ignore USER SUSPEND"
2009 This option will ignore USER SUSPEND requests. On machines with a
2010 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2011 series notebooks, it is necessary to say Y because of a BIOS bug.
2013 config APM_DO_ENABLE
2014 bool "Enable PM at boot time"
2016 Enable APM features at boot time. From page 36 of the APM BIOS
2017 specification: "When disabled, the APM BIOS does not automatically
2018 power manage devices, enter the Standby State, enter the Suspend
2019 State, or take power saving steps in response to CPU Idle calls."
2020 This driver will make CPU Idle calls when Linux is idle (unless this
2021 feature is turned off -- see "Do CPU IDLE calls", below). This
2022 should always save battery power, but more complicated APM features
2023 will be dependent on your BIOS implementation. You may need to turn
2024 this option off if your computer hangs at boot time when using APM
2025 support, or if it beeps continuously instead of suspending. Turn
2026 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2027 T400CDT. This is off by default since most machines do fine without
2032 bool "Make CPU Idle calls when idle"
2034 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2035 On some machines, this can activate improved power savings, such as
2036 a slowed CPU clock rate, when the machine is idle. These idle calls
2037 are made after the idle loop has run for some length of time (e.g.,
2038 333 mS). On some machines, this will cause a hang at boot time or
2039 whenever the CPU becomes idle. (On machines with more than one CPU,
2040 this option does nothing.)
2042 config APM_DISPLAY_BLANK
2043 bool "Enable console blanking using APM"
2045 Enable console blanking using the APM. Some laptops can use this to
2046 turn off the LCD backlight when the screen blanker of the Linux
2047 virtual console blanks the screen. Note that this is only used by
2048 the virtual console screen blanker, and won't turn off the backlight
2049 when using the X Window system. This also doesn't have anything to
2050 do with your VESA-compliant power-saving monitor. Further, this
2051 option doesn't work for all laptops -- it might not turn off your
2052 backlight at all, or it might print a lot of errors to the console,
2053 especially if you are using gpm.
2055 config APM_ALLOW_INTS
2056 bool "Allow interrupts during APM BIOS calls"
2058 Normally we disable external interrupts while we are making calls to
2059 the APM BIOS as a measure to lessen the effects of a badly behaving
2060 BIOS implementation. The BIOS should reenable interrupts if it
2061 needs to. Unfortunately, some BIOSes do not -- especially those in
2062 many of the newer IBM Thinkpads. If you experience hangs when you
2063 suspend, try setting this to Y. Otherwise, say N.
2067 source "drivers/cpufreq/Kconfig"
2069 source "drivers/cpuidle/Kconfig"
2071 source "drivers/idle/Kconfig"
2076 menu "Bus options (PCI etc.)"
2082 Find out whether you have a PCI motherboard. PCI is the name of a
2083 bus system, i.e. the way the CPU talks to the other stuff inside
2084 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2085 VESA. If you have PCI, say Y, otherwise N.
2088 prompt "PCI access mode"
2089 depends on X86_32 && PCI
2092 On PCI systems, the BIOS can be used to detect the PCI devices and
2093 determine their configuration. However, some old PCI motherboards
2094 have BIOS bugs and may crash if this is done. Also, some embedded
2095 PCI-based systems don't have any BIOS at all. Linux can also try to
2096 detect the PCI hardware directly without using the BIOS.
2098 With this option, you can specify how Linux should detect the
2099 PCI devices. If you choose "BIOS", the BIOS will be used,
2100 if you choose "Direct", the BIOS won't be used, and if you
2101 choose "MMConfig", then PCI Express MMCONFIG will be used.
2102 If you choose "Any", the kernel will try MMCONFIG, then the
2103 direct access method and falls back to the BIOS if that doesn't
2104 work. If unsure, go with the default, which is "Any".
2109 config PCI_GOMMCONFIG
2126 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2128 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2131 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2135 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2139 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2143 depends on PCI && XEN
2151 bool "Support mmconfig PCI config space access"
2152 depends on X86_64 && PCI && ACPI
2154 config PCI_CNB20LE_QUIRK
2155 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2158 Read the PCI windows out of the CNB20LE host bridge. This allows
2159 PCI hotplug to work on systems with the CNB20LE chipset which do
2162 There's no public spec for this chipset, and this functionality
2163 is known to be incomplete.
2165 You should say N unless you know you need this.
2167 source "drivers/pci/pcie/Kconfig"
2169 source "drivers/pci/Kconfig"
2171 # x86_64 have no ISA slots, but can have ISA-style DMA.
2173 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2176 Enables ISA-style DMA support for devices requiring such controllers.
2184 Find out whether you have ISA slots on your motherboard. ISA is the
2185 name of a bus system, i.e. the way the CPU talks to the other stuff
2186 inside your box. Other bus systems are PCI, EISA, MicroChannel
2187 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2188 newer boards don't support it. If you have ISA, say Y, otherwise N.
2194 The Extended Industry Standard Architecture (EISA) bus was
2195 developed as an open alternative to the IBM MicroChannel bus.
2197 The EISA bus provided some of the features of the IBM MicroChannel
2198 bus while maintaining backward compatibility with cards made for
2199 the older ISA bus. The EISA bus saw limited use between 1988 and
2200 1995 when it was made obsolete by the PCI bus.
2202 Say Y here if you are building a kernel for an EISA-based machine.
2206 source "drivers/eisa/Kconfig"
2209 tristate "NatSemi SCx200 support"
2211 This provides basic support for National Semiconductor's
2212 (now AMD's) Geode processors. The driver probes for the
2213 PCI-IDs of several on-chip devices, so its a good dependency
2214 for other scx200_* drivers.
2216 If compiled as a module, the driver is named scx200.
2218 config SCx200HR_TIMER
2219 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2223 This driver provides a clocksource built upon the on-chip
2224 27MHz high-resolution timer. Its also a workaround for
2225 NSC Geode SC-1100's buggy TSC, which loses time when the
2226 processor goes idle (as is done by the scheduler). The
2227 other workaround is idle=poll boot option.
2230 bool "One Laptop Per Child support"
2237 Add support for detecting the unique features of the OLPC
2241 bool "OLPC XO-1 Power Management"
2242 depends on OLPC && MFD_CS5535 && PM_SLEEP
2245 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2248 bool "OLPC XO-1 Real Time Clock"
2249 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2251 Add support for the XO-1 real time clock, which can be used as a
2252 programmable wakeup source.
2255 bool "OLPC XO-1 SCI extras"
2256 depends on OLPC && OLPC_XO1_PM
2262 Add support for SCI-based features of the OLPC XO-1 laptop:
2263 - EC-driven system wakeups
2267 - AC adapter status updates
2268 - Battery status updates
2270 config OLPC_XO15_SCI
2271 bool "OLPC XO-1.5 SCI extras"
2272 depends on OLPC && ACPI
2275 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2276 - EC-driven system wakeups
2277 - AC adapter status updates
2278 - Battery status updates
2281 bool "PCEngines ALIX System Support (LED setup)"
2284 This option enables system support for the PCEngines ALIX.
2285 At present this just sets up LEDs for GPIO control on
2286 ALIX2/3/6 boards. However, other system specific setup should
2289 Note: You must still enable the drivers for GPIO and LED support
2290 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2292 Note: You have to set alix.force=1 for boards with Award BIOS.
2295 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2298 This option enables system support for the Soekris Engineering net5501.
2301 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2305 This option enables system support for the Traverse Technologies GEOS.
2308 bool "Technologic Systems TS-5500 platform support"
2310 select CHECK_SIGNATURE
2314 This option enables system support for the Technologic Systems TS-5500.
2320 depends on CPU_SUP_AMD && PCI
2322 source "drivers/pcmcia/Kconfig"
2324 source "drivers/pci/hotplug/Kconfig"
2327 tristate "RapidIO support"
2331 If enabled this option will include drivers and the core
2332 infrastructure code to support RapidIO interconnect devices.
2334 source "drivers/rapidio/Kconfig"
2337 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2339 Firmwares often provide initial graphics framebuffers so the BIOS,
2340 bootloader or kernel can show basic video-output during boot for
2341 user-guidance and debugging. Historically, x86 used the VESA BIOS
2342 Extensions and EFI-framebuffers for this, which are mostly limited
2344 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2345 framebuffers so the new generic system-framebuffer drivers can be
2346 used on x86. If the framebuffer is not compatible with the generic
2347 modes, it is adverticed as fallback platform framebuffer so legacy
2348 drivers like efifb, vesafb and uvesafb can pick it up.
2349 If this option is not selected, all system framebuffers are always
2350 marked as fallback platform framebuffers as usual.
2352 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2353 not be able to pick up generic system framebuffers if this option
2354 is selected. You are highly encouraged to enable simplefb as
2355 replacement if you select this option. simplefb can correctly deal
2356 with generic system framebuffers. But you should still keep vesafb
2357 and others enabled as fallback if a system framebuffer is
2358 incompatible with simplefb.
2365 menu "Executable file formats / Emulations"
2367 source "fs/Kconfig.binfmt"
2369 config IA32_EMULATION
2370 bool "IA32 Emulation"
2373 select COMPAT_BINFMT_ELF
2376 Include code to run legacy 32-bit programs under a
2377 64-bit kernel. You should likely turn this on, unless you're
2378 100% sure that you don't have any 32-bit programs left.
2381 tristate "IA32 a.out support"
2382 depends on IA32_EMULATION
2384 Support old a.out binaries in the 32bit emulation.
2387 bool "x32 ABI for 64-bit mode"
2388 depends on X86_64 && IA32_EMULATION
2390 Include code to run binaries for the x32 native 32-bit ABI
2391 for 64-bit processors. An x32 process gets access to the
2392 full 64-bit register file and wide data path while leaving
2393 pointers at 32 bits for smaller memory footprint.
2395 You will need a recent binutils (2.22 or later) with
2396 elf32_x86_64 support enabled to compile a kernel with this
2401 depends on IA32_EMULATION || X86_X32
2402 select ARCH_WANT_OLD_COMPAT_IPC
2405 config COMPAT_FOR_U64_ALIGNMENT
2408 config SYSVIPC_COMPAT
2420 config HAVE_ATOMIC_IOMAP
2424 config X86_DEV_DMA_OPS
2426 depends on X86_64 || STA2X11
2428 config X86_DMA_REMAP
2441 source "net/Kconfig"
2443 source "drivers/Kconfig"
2445 source "drivers/firmware/Kconfig"
2449 source "arch/x86/Kconfig.debug"
2451 source "security/Kconfig"
2453 source "crypto/Kconfig"
2455 source "arch/x86/kvm/Kconfig"
2457 source "lib/Kconfig"