| blob | fc20fdc0f7f2c637fba6b24b4197738995130f1d |
1 # x86 configuration
2 mainmenu "Linux Kernel Configuration for x86"
4 # Select 32 or 64 bit
5 config 64BIT
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
8 ---help---
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
12 config X86_32
13 def_bool !64BIT
15 config X86_64
16 def_bool 64BIT
18 ### Arch settings
19 config X86
20 def_bool y
21 select HAVE_AOUT if X86_32
22 select HAVE_READQ
23 select HAVE_WRITEQ
24 select HAVE_UNSTABLE_SCHED_CLOCK
25 select HAVE_IDE
26 select HAVE_OPROFILE
27 select HAVE_PERF_COUNTERS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
29 select HAVE_KPROBES
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
32 select HAVE_DMA_ATTRS
33 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_DYNAMIC_FTRACE
36 select HAVE_FUNCTION_TRACER
37 select HAVE_FUNCTION_GRAPH_TRACER
38 select HAVE_FUNCTION_GRAPH_FP_TEST
39 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
40 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
41 select HAVE_SYSCALL_TRACEPOINTS
42 select HAVE_KVM
43 select HAVE_ARCH_KGDB
44 select HAVE_ARCH_TRACEHOOK
45 select HAVE_GENERIC_DMA_COHERENT if X86_32
46 select HAVE_EFFICIENT_UNALIGNED_ACCESS
47 select USER_STACKTRACE_SUPPORT
48 select HAVE_DMA_API_DEBUG
49 select HAVE_KERNEL_GZIP
50 select HAVE_KERNEL_BZIP2
51 select HAVE_KERNEL_LZMA
52 select HAVE_ARCH_KMEMCHECK
54 config OUTPUT_FORMAT
55 string
56 default "elf32-i386" if X86_32
57 default "elf64-x86-64" if X86_64
59 config ARCH_DEFCONFIG
60 string
61 default "arch/x86/configs/i386_defconfig" if X86_32
62 default "arch/x86/configs/x86_64_defconfig" if X86_64
64 config GENERIC_TIME
65 def_bool y
67 config GENERIC_CMOS_UPDATE
68 def_bool y
70 config CLOCKSOURCE_WATCHDOG
71 def_bool y
73 config GENERIC_CLOCKEVENTS
74 def_bool y
76 config GENERIC_CLOCKEVENTS_BROADCAST
77 def_bool y
78 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
80 config LOCKDEP_SUPPORT
81 def_bool y
83 config STACKTRACE_SUPPORT
84 def_bool y
86 config HAVE_LATENCYTOP_SUPPORT
87 def_bool y
89 config FAST_CMPXCHG_LOCAL
90 bool
91 default y
93 config MMU
94 def_bool y
96 config ZONE_DMA
97 def_bool y
99 config SBUS
100 bool
102 config GENERIC_ISA_DMA
103 def_bool y
105 config GENERIC_IOMAP
106 def_bool y
108 config GENERIC_BUG
109 def_bool y
110 depends on BUG
111 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
113 config GENERIC_BUG_RELATIVE_POINTERS
114 bool
116 config GENERIC_HWEIGHT
117 def_bool y
119 config GENERIC_GPIO
120 bool
122 config ARCH_MAY_HAVE_PC_FDC
123 def_bool y
125 config RWSEM_GENERIC_SPINLOCK
126 def_bool !X86_XADD
128 config RWSEM_XCHGADD_ALGORITHM
129 def_bool X86_XADD
131 config ARCH_HAS_CPU_IDLE_WAIT
132 def_bool y
134 config GENERIC_CALIBRATE_DELAY
135 def_bool y
137 config GENERIC_TIME_VSYSCALL
138 bool
139 default X86_64
141 config ARCH_HAS_CPU_RELAX
142 def_bool y
144 config ARCH_HAS_DEFAULT_IDLE
145 def_bool y
147 config ARCH_HAS_CACHE_LINE_SIZE
148 def_bool y
150 config HAVE_SETUP_PER_CPU_AREA
151 def_bool y
153 config HAVE_DYNAMIC_PER_CPU_AREA
154 def_bool y
156 config HAVE_CPUMASK_OF_CPU_MAP
157 def_bool X86_64_SMP
159 config ARCH_HIBERNATION_POSSIBLE
160 def_bool y
162 config ARCH_SUSPEND_POSSIBLE
163 def_bool y
165 config ZONE_DMA32
166 bool
167 default X86_64
169 config ARCH_POPULATES_NODE_MAP
170 def_bool y
172 config AUDIT_ARCH
173 bool
174 default X86_64
176 config ARCH_SUPPORTS_OPTIMIZED_INLINING
177 def_bool y
179 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
180 def_bool y
182 # Use the generic interrupt handling code in kernel/irq/:
183 config GENERIC_HARDIRQS
184 bool
185 default y
187 config GENERIC_HARDIRQS_NO__DO_IRQ
188 def_bool y
190 config GENERIC_IRQ_PROBE
191 bool
192 default y
194 config GENERIC_PENDING_IRQ
195 bool
196 depends on GENERIC_HARDIRQS && SMP
197 default y
199 config USE_GENERIC_SMP_HELPERS
200 def_bool y
201 depends on SMP
203 config X86_32_SMP
204 def_bool y
205 depends on X86_32 && SMP
207 config X86_64_SMP
208 def_bool y
209 depends on X86_64 && SMP
211 config X86_HT
212 bool
213 depends on SMP
214 default y
216 config X86_TRAMPOLINE
217 bool
218 depends on SMP || (64BIT && ACPI_SLEEP)
219 default y
221 config X86_32_LAZY_GS
222 def_bool y
223 depends on X86_32 && !CC_STACKPROTECTOR
225 config KTIME_SCALAR
226 def_bool X86_32
227 source "init/Kconfig"
228 source "kernel/Kconfig.freezer"
230 menu "Processor type and features"
232 source "kernel/time/Kconfig"
234 config SMP
235 bool "Symmetric multi-processing support"
236 ---help---
237 This enables support for systems with more than one CPU. If you have
238 a system with only one CPU, like most personal computers, say N. If
239 you have a system with more than one CPU, say Y.
241 If you say N here, the kernel will run on single and multiprocessor
242 machines, but will use only one CPU of a multiprocessor machine. If
243 you say Y here, the kernel will run on many, but not all,
244 singleprocessor machines. On a singleprocessor machine, the kernel
245 will run faster if you say N here.
247 Note that if you say Y here and choose architecture "586" or
248 "Pentium" under "Processor family", the kernel will not work on 486
249 architectures. Similarly, multiprocessor kernels for the "PPro"
250 architecture may not work on all Pentium based boards.
252 People using multiprocessor machines who say Y here should also say
253 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
254 Management" code will be disabled if you say Y here.
256 See also <file:Documentation/i386/IO-APIC.txt>,
257 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
258 <http://www.tldp.org/docs.html#howto>.
260 If you don't know what to do here, say N.
262 config X86_X2APIC
263 bool "Support x2apic"
264 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
265 ---help---
266 This enables x2apic support on CPUs that have this feature.
268 This allows 32-bit apic IDs (so it can support very large systems),
269 and accesses the local apic via MSRs not via mmio.
271 If you don't know what to do here, say N.
273 config SPARSE_IRQ
274 bool "Support sparse irq numbering"
275 depends on PCI_MSI || HT_IRQ
276 ---help---
277 This enables support for sparse irqs. This is useful for distro
278 kernels that want to define a high CONFIG_NR_CPUS value but still
279 want to have low kernel memory footprint on smaller machines.
281 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
282 out the irq_desc[] array in a more NUMA-friendly way. )
284 If you don't know what to do here, say N.
286 config NUMA_IRQ_DESC
287 def_bool y
288 depends on SPARSE_IRQ && NUMA
290 config X86_MPPARSE
291 bool "Enable MPS table" if ACPI
292 default y
293 depends on X86_LOCAL_APIC
294 ---help---
295 For old smp systems that do not have proper acpi support. Newer systems
296 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
298 config X86_BIGSMP
299 bool "Support for big SMP systems with more than 8 CPUs"
300 depends on X86_32 && SMP
301 ---help---
302 This option is needed for the systems that have more than 8 CPUs
304 if X86_32
305 config X86_EXTENDED_PLATFORM
306 bool "Support for extended (non-PC) x86 platforms"
307 default y
308 ---help---
309 If you disable this option then the kernel will only support
310 standard PC platforms. (which covers the vast majority of
311 systems out there.)
313 If you enable this option then you'll be able to select support
314 for the following (non-PC) 32 bit x86 platforms:
315 AMD Elan
316 NUMAQ (IBM/Sequent)
317 RDC R-321x SoC
318 SGI 320/540 (Visual Workstation)
319 Summit/EXA (IBM x440)
320 Unisys ES7000 IA32 series
322 If you have one of these systems, or if you want to build a
323 generic distribution kernel, say Y here - otherwise say N.
324 endif
326 if X86_64
327 config X86_EXTENDED_PLATFORM
328 bool "Support for extended (non-PC) x86 platforms"
329 default y
330 ---help---
331 If you disable this option then the kernel will only support
332 standard PC platforms. (which covers the vast majority of
333 systems out there.)
335 If you enable this option then you'll be able to select support
336 for the following (non-PC) 64 bit x86 platforms:
337 ScaleMP vSMP
338 SGI Ultraviolet
340 If you have one of these systems, or if you want to build a
341 generic distribution kernel, say Y here - otherwise say N.
342 endif
343 # This is an alphabetically sorted list of 64 bit extended platforms
344 # Please maintain the alphabetic order if and when there are additions
346 config X86_VSMP
347 bool "ScaleMP vSMP"
348 select PARAVIRT
349 depends on X86_64 && PCI
350 depends on X86_EXTENDED_PLATFORM
351 ---help---
352 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
353 supposed to run on these EM64T-based machines. Only choose this option
354 if you have one of these machines.
356 config X86_UV
357 bool "SGI Ultraviolet"
358 depends on X86_64
359 depends on X86_EXTENDED_PLATFORM
360 depends on NUMA
361 depends on X86_X2APIC
362 ---help---
363 This option is needed in order to support SGI Ultraviolet systems.
364 If you don't have one of these, you should say N here.
366 # Following is an alphabetically sorted list of 32 bit extended platforms
367 # Please maintain the alphabetic order if and when there are additions
369 config X86_ELAN
370 bool "AMD Elan"
371 depends on X86_32
372 depends on X86_EXTENDED_PLATFORM
373 ---help---
374 Select this for an AMD Elan processor.
376 Do not use this option for K6/Athlon/Opteron processors!
378 If unsure, choose "PC-compatible" instead.
380 config X86_RDC321X
381 bool "RDC R-321x SoC"
382 depends on X86_32
383 depends on X86_EXTENDED_PLATFORM
384 select M486
385 select X86_REBOOTFIXUPS
386 ---help---
387 This option is needed for RDC R-321x system-on-chip, also known
388 as R-8610-(G).
389 If you don't have one of these chips, you should say N here.
391 config X86_32_NON_STANDARD
392 bool "Support non-standard 32-bit SMP architectures"
393 depends on X86_32 && SMP
394 depends on X86_EXTENDED_PLATFORM
395 ---help---
396 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
397 subarchitectures. It is intended for a generic binary kernel.
398 if you select them all, kernel will probe it one by one. and will
399 fallback to default.
401 # Alphabetically sorted list of Non standard 32 bit platforms
403 config X86_NUMAQ
404 bool "NUMAQ (IBM/Sequent)"
405 depends on X86_32_NON_STANDARD
406 select NUMA
407 select X86_MPPARSE
408 ---help---
409 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
410 NUMA multiquad box. This changes the way that processors are
411 bootstrapped, and uses Clustered Logical APIC addressing mode instead
412 of Flat Logical. You will need a new lynxer.elf file to flash your
413 firmware with - send email to <Martin.Bligh@us.ibm.com>.
415 config X86_VISWS
416 bool "SGI 320/540 (Visual Workstation)"
417 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
418 depends on X86_32_NON_STANDARD
419 ---help---
420 The SGI Visual Workstation series is an IA32-based workstation
421 based on SGI systems chips with some legacy PC hardware attached.
423 Say Y here to create a kernel to run on the SGI 320 or 540.
425 A kernel compiled for the Visual Workstation will run on general
426 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
428 config X86_SUMMIT
429 bool "Summit/EXA (IBM x440)"
430 depends on X86_32_NON_STANDARD
431 ---help---
432 This option is needed for IBM systems that use the Summit/EXA chipset.
433 In particular, it is needed for the x440.
435 config X86_ES7000
436 bool "Unisys ES7000 IA32 series"
437 depends on X86_32_NON_STANDARD && X86_BIGSMP
438 ---help---
439 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
440 supposed to run on an IA32-based Unisys ES7000 system.
442 config SCHED_OMIT_FRAME_POINTER
443 def_bool y
444 prompt "Single-depth WCHAN output"
445 depends on X86
446 ---help---
447 Calculate simpler /proc/<PID>/wchan values. If this option
448 is disabled then wchan values will recurse back to the
449 caller function. This provides more accurate wchan values,
450 at the expense of slightly more scheduling overhead.
452 If in doubt, say "Y".
454 menuconfig PARAVIRT_GUEST
455 bool "Paravirtualized guest support"
456 ---help---
457 Say Y here to get to see options related to running Linux under
458 various hypervisors. This option alone does not add any kernel code.
460 If you say N, all options in this submenu will be skipped and disabled.
462 if PARAVIRT_GUEST
464 source "arch/x86/xen/Kconfig"
466 config VMI
467 bool "VMI Guest support"
468 select PARAVIRT
469 depends on X86_32
470 ---help---
471 VMI provides a paravirtualized interface to the VMware ESX server
472 (it could be used by other hypervisors in theory too, but is not
473 at the moment), by linking the kernel to a GPL-ed ROM module
474 provided by the hypervisor.
476 config KVM_CLOCK
477 bool "KVM paravirtualized clock"
478 select PARAVIRT
479 select PARAVIRT_CLOCK
480 ---help---
481 Turning on this option will allow you to run a paravirtualized clock
482 when running over the KVM hypervisor. Instead of relying on a PIT
483 (or probably other) emulation by the underlying device model, the host
484 provides the guest with timing infrastructure such as time of day, and
485 system time
487 config KVM_GUEST
488 bool "KVM Guest support"
489 select PARAVIRT
490 ---help---
491 This option enables various optimizations for running under the KVM
492 hypervisor.
494 source "arch/x86/lguest/Kconfig"
496 config PARAVIRT
497 bool "Enable paravirtualization code"
498 ---help---
499 This changes the kernel so it can modify itself when it is run
500 under a hypervisor, potentially improving performance significantly
501 over full virtualization. However, when run without a hypervisor
502 the kernel is theoretically slower and slightly larger.
504 config PARAVIRT_SPINLOCKS
505 bool "Paravirtualization layer for spinlocks"
506 depends on PARAVIRT && SMP && EXPERIMENTAL
507 ---help---
508 Paravirtualized spinlocks allow a pvops backend to replace the
509 spinlock implementation with something virtualization-friendly
510 (for example, block the virtual CPU rather than spinning).
512 Unfortunately the downside is an up to 5% performance hit on
513 native kernels, with various workloads.
515 If you are unsure how to answer this question, answer N.
517 config PARAVIRT_CLOCK
518 bool
519 default n
521 endif
523 config PARAVIRT_DEBUG
524 bool "paravirt-ops debugging"
525 depends on PARAVIRT && DEBUG_KERNEL
526 ---help---
527 Enable to debug paravirt_ops internals. Specifically, BUG if
528 a paravirt_op is missing when it is called.
530 config MEMTEST
531 bool "Memtest"
532 ---help---
533 This option adds a kernel parameter 'memtest', which allows memtest
534 to be set.
535 memtest=0, mean disabled; -- default
536 memtest=1, mean do 1 test pattern;
537 ...
538 memtest=4, mean do 4 test patterns.
539 If you are unsure how to answer this question, answer N.
541 config X86_SUMMIT_NUMA
542 def_bool y
543 depends on X86_32 && NUMA && X86_32_NON_STANDARD
545 config X86_CYCLONE_TIMER
546 def_bool y
547 depends on X86_32_NON_STANDARD
549 source "arch/x86/Kconfig.cpu"
551 config HPET_TIMER
552 def_bool X86_64
553 prompt "HPET Timer Support" if X86_32
554 ---help---
555 Use the IA-PC HPET (High Precision Event Timer) to manage
556 time in preference to the PIT and RTC, if a HPET is
557 present.
558 HPET is the next generation timer replacing legacy 8254s.
559 The HPET provides a stable time base on SMP
560 systems, unlike the TSC, but it is more expensive to access,
561 as it is off-chip. You can find the HPET spec at
562 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
564 You can safely choose Y here. However, HPET will only be
565 activated if the platform and the BIOS support this feature.
566 Otherwise the 8254 will be used for timing services.
568 Choose N to continue using the legacy 8254 timer.
570 config HPET_EMULATE_RTC
571 def_bool y
572 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
574 # Mark as embedded because too many people got it wrong.
575 # The code disables itself when not needed.
576 config DMI
577 default y
578 bool "Enable DMI scanning" if EMBEDDED
579 ---help---
580 Enabled scanning of DMI to identify machine quirks. Say Y
581 here unless you have verified that your setup is not
582 affected by entries in the DMI blacklist. Required by PNP
583 BIOS code.
585 config GART_IOMMU
586 bool "GART IOMMU support" if EMBEDDED
587 default y
588 select SWIOTLB
589 depends on X86_64 && PCI
590 ---help---
591 Support for full DMA access of devices with 32bit memory access only
592 on systems with more than 3GB. This is usually needed for USB,
593 sound, many IDE/SATA chipsets and some other devices.
594 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
595 based hardware IOMMU and a software bounce buffer based IOMMU used
596 on Intel systems and as fallback.
597 The code is only active when needed (enough memory and limited
598 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
599 too.
601 config CALGARY_IOMMU
602 bool "IBM Calgary IOMMU support"
603 select SWIOTLB
604 depends on X86_64 && PCI && EXPERIMENTAL
605 ---help---
606 Support for hardware IOMMUs in IBM's xSeries x366 and x460
607 systems. Needed to run systems with more than 3GB of memory
608 properly with 32-bit PCI devices that do not support DAC
609 (Double Address Cycle). Calgary also supports bus level
610 isolation, where all DMAs pass through the IOMMU. This
611 prevents them from going anywhere except their intended
612 destination. This catches hard-to-find kernel bugs and
613 mis-behaving drivers and devices that do not use the DMA-API
614 properly to set up their DMA buffers. The IOMMU can be
615 turned off at boot time with the iommu=off parameter.
616 Normally the kernel will make the right choice by itself.
617 If unsure, say Y.
619 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
620 def_bool y
621 prompt "Should Calgary be enabled by default?"
622 depends on CALGARY_IOMMU
623 ---help---
624 Should Calgary be enabled by default? if you choose 'y', Calgary
625 will be used (if it exists). If you choose 'n', Calgary will not be
626 used even if it exists. If you choose 'n' and would like to use
627 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
628 If unsure, say Y.
630 config AMD_IOMMU
631 bool "AMD IOMMU support"
632 select SWIOTLB
633 select PCI_MSI
634 depends on X86_64 && PCI && ACPI
635 ---help---
636 With this option you can enable support for AMD IOMMU hardware in
637 your system. An IOMMU is a hardware component which provides
638 remapping of DMA memory accesses from devices. With an AMD IOMMU you
639 can isolate the the DMA memory of different devices and protect the
640 system from misbehaving device drivers or hardware.
642 You can find out if your system has an AMD IOMMU if you look into
643 your BIOS for an option to enable it or if you have an IVRS ACPI
644 table.
646 config AMD_IOMMU_STATS
647 bool "Export AMD IOMMU statistics to debugfs"
648 depends on AMD_IOMMU
649 select DEBUG_FS
650 ---help---
651 This option enables code in the AMD IOMMU driver to collect various
652 statistics about whats happening in the driver and exports that
653 information to userspace via debugfs.
654 If unsure, say N.
656 # need this always selected by IOMMU for the VIA workaround
657 config SWIOTLB
658 def_bool y if X86_64
659 ---help---
660 Support for software bounce buffers used on x86-64 systems
661 which don't have a hardware IOMMU (e.g. the current generation
662 of Intel's x86-64 CPUs). Using this PCI devices which can only
663 access 32-bits of memory can be used on systems with more than
664 3 GB of memory. If unsure, say Y.
666 config IOMMU_HELPER
667 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
669 config IOMMU_API
670 def_bool (AMD_IOMMU || DMAR)
672 config MAXSMP
673 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
674 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
675 select CPUMASK_OFFSTACK
676 default n
677 ---help---
678 Configure maximum number of CPUS and NUMA Nodes for this architecture.
679 If unsure, say N.
681 config NR_CPUS
682 int "Maximum number of CPUs" if SMP && !MAXSMP
683 range 2 8 if SMP && X86_32 && !X86_BIGSMP
684 range 2 512 if SMP && !MAXSMP
685 default "1" if !SMP
686 default "4096" if MAXSMP
687 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
688 default "8" if SMP
689 ---help---
690 This allows you to specify the maximum number of CPUs which this
691 kernel will support. The maximum supported value is 512 and the
692 minimum value which makes sense is 2.
694 This is purely to save memory - each supported CPU adds
695 approximately eight kilobytes to the kernel image.
697 config SCHED_SMT
698 bool "SMT (Hyperthreading) scheduler support"
699 depends on X86_HT
700 ---help---
701 SMT scheduler support improves the CPU scheduler's decision making
702 when dealing with Intel Pentium 4 chips with HyperThreading at a
703 cost of slightly increased overhead in some places. If unsure say
704 N here.
706 config SCHED_MC
707 def_bool y
708 prompt "Multi-core scheduler support"
709 depends on X86_HT
710 ---help---
711 Multi-core scheduler support improves the CPU scheduler's decision
712 making when dealing with multi-core CPU chips at a cost of slightly
713 increased overhead in some places. If unsure say N here.
715 source "kernel/Kconfig.preempt"
717 config X86_UP_APIC
718 bool "Local APIC support on uniprocessors"
719 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
720 ---help---
721 A local APIC (Advanced Programmable Interrupt Controller) is an
722 integrated interrupt controller in the CPU. If you have a single-CPU
723 system which has a processor with a local APIC, you can say Y here to
724 enable and use it. If you say Y here even though your machine doesn't
725 have a local APIC, then the kernel will still run with no slowdown at
726 all. The local APIC supports CPU-generated self-interrupts (timer,
727 performance counters), and the NMI watchdog which detects hard
728 lockups.
730 config X86_UP_IOAPIC
731 bool "IO-APIC support on uniprocessors"
732 depends on X86_UP_APIC
733 ---help---
734 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
735 SMP-capable replacement for PC-style interrupt controllers. Most
736 SMP systems and many recent uniprocessor systems have one.
738 If you have a single-CPU system with an IO-APIC, you can say Y here
739 to use it. If you say Y here even though your machine doesn't have
740 an IO-APIC, then the kernel will still run with no slowdown at all.
742 config X86_LOCAL_APIC
743 def_bool y
744 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
746 config X86_IO_APIC
747 def_bool y
748 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
750 config X86_VISWS_APIC
751 def_bool y
752 depends on X86_32 && X86_VISWS
754 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
755 bool "Reroute for broken boot IRQs"
756 default n
757 depends on X86_IO_APIC
758 ---help---
759 This option enables a workaround that fixes a source of
760 spurious interrupts. This is recommended when threaded
761 interrupt handling is used on systems where the generation of
762 superfluous "boot interrupts" cannot be disabled.
764 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
765 entry in the chipset's IO-APIC is masked (as, e.g. the RT
766 kernel does during interrupt handling). On chipsets where this
767 boot IRQ generation cannot be disabled, this workaround keeps
768 the original IRQ line masked so that only the equivalent "boot
769 IRQ" is delivered to the CPUs. The workaround also tells the
770 kernel to set up the IRQ handler on the boot IRQ line. In this
771 way only one interrupt is delivered to the kernel. Otherwise
772 the spurious second interrupt may cause the kernel to bring
773 down (vital) interrupt lines.
775 Only affects "broken" chipsets. Interrupt sharing may be
776 increased on these systems.
778 config X86_MCE
779 bool "Machine Check Exception"
780 ---help---
781 Machine Check Exception support allows the processor to notify the
782 kernel if it detects a problem (e.g. overheating, component failure).
783 The action the kernel takes depends on the severity of the problem,
784 ranging from a warning message on the console, to halting the machine.
785 Your processor must be a Pentium or newer to support this - check the
786 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
787 have a design flaw which leads to false MCE events - hence MCE is
788 disabled on all P5 processors, unless explicitly enabled with "mce"
789 as a boot argument. Similarly, if MCE is built in and creates a
790 problem on some new non-standard machine, you can boot with "nomce"
791 to disable it. MCE support simply ignores non-MCE processors like
792 the 386 and 486, so nearly everyone can say Y here.
794 config X86_OLD_MCE
795 depends on X86_32 && X86_MCE
796 bool "Use legacy machine check code (will go away)"
797 default n
798 select X86_ANCIENT_MCE
799 ---help---
800 Use the old i386 machine check code. This is merely intended for
801 testing in a transition period. Try this if you run into any machine
802 check related software problems, but report the problem to
803 linux-kernel. When in doubt say no.
805 config X86_NEW_MCE
806 depends on X86_MCE
807 bool
808 default y if (!X86_OLD_MCE && X86_32) || X86_64
810 config X86_MCE_INTEL
811 def_bool y
812 prompt "Intel MCE features"
813 depends on X86_NEW_MCE && X86_LOCAL_APIC
814 ---help---
815 Additional support for intel specific MCE features such as
816 the thermal monitor.
818 config X86_MCE_AMD
819 def_bool y
820 prompt "AMD MCE features"
821 depends on X86_NEW_MCE && X86_LOCAL_APIC
822 ---help---
823 Additional support for AMD specific MCE features such as
824 the DRAM Error Threshold.
826 config X86_ANCIENT_MCE
827 def_bool n
828 depends on X86_32
829 prompt "Support for old Pentium 5 / WinChip machine checks"
830 ---help---
831 Include support for machine check handling on old Pentium 5 or WinChip
832 systems. These typically need to be enabled explicitely on the command
833 line.
835 config X86_MCE_THRESHOLD
836 depends on X86_MCE_AMD || X86_MCE_INTEL
837 bool
838 default y
840 config X86_MCE_INJECT
841 depends on X86_NEW_MCE
842 tristate "Machine check injector support"
843 ---help---
844 Provide support for injecting machine checks for testing purposes.
845 If you don't know what a machine check is and you don't do kernel
846 QA it is safe to say n.
848 config X86_MCE_NONFATAL
849 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
850 depends on X86_OLD_MCE
851 ---help---
852 Enabling this feature starts a timer that triggers every 5 seconds which
853 will look at the machine check registers to see if anything happened.
854 Non-fatal problems automatically get corrected (but still logged).
855 Disable this if you don't want to see these messages.
856 Seeing the messages this option prints out may be indicative of dying
857 or out-of-spec (ie, overclocked) hardware.
858 This option only does something on certain CPUs.
859 (AMD Athlon/Duron and Intel Pentium 4)
861 config X86_MCE_P4THERMAL
862 bool "check for P4 thermal throttling interrupt."
863 depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
864 ---help---
865 Enabling this feature will cause a message to be printed when the P4
866 enters thermal throttling.
868 config X86_THERMAL_VECTOR
869 def_bool y
870 depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
872 config VM86
873 bool "Enable VM86 support" if EMBEDDED
874 default y
875 depends on X86_32
876 ---help---
877 This option is required by programs like DOSEMU to run 16-bit legacy
878 code on X86 processors. It also may be needed by software like
879 XFree86 to initialize some video cards via BIOS. Disabling this
880 option saves about 6k.
882 config TOSHIBA
883 tristate "Toshiba Laptop support"
884 depends on X86_32
885 ---help---
886 This adds a driver to safely access the System Management Mode of
887 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
888 not work on models with a Phoenix BIOS. The System Management Mode
889 is used to set the BIOS and power saving options on Toshiba portables.
891 For information on utilities to make use of this driver see the
892 Toshiba Linux utilities web site at:
893 <http://www.buzzard.org.uk/toshiba/>.
895 Say Y if you intend to run this kernel on a Toshiba portable.
896 Say N otherwise.
898 config I8K
899 tristate "Dell laptop support"
900 ---help---
901 This adds a driver to safely access the System Management Mode
902 of the CPU on the Dell Inspiron 8000. The System Management Mode
903 is used to read cpu temperature and cooling fan status and to
904 control the fans on the I8K portables.
906 This driver has been tested only on the Inspiron 8000 but it may
907 also work with other Dell laptops. You can force loading on other
908 models by passing the parameter `force=1' to the module. Use at
909 your own risk.
911 For information on utilities to make use of this driver see the
912 I8K Linux utilities web site at:
913 <http://people.debian.org/~dz/i8k/>
915 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
916 Say N otherwise.
918 config X86_REBOOTFIXUPS
919 bool "Enable X86 board specific fixups for reboot"
920 depends on X86_32
921 ---help---
922 This enables chipset and/or board specific fixups to be done
923 in order to get reboot to work correctly. This is only needed on
924 some combinations of hardware and BIOS. The symptom, for which
925 this config is intended, is when reboot ends with a stalled/hung
926 system.
928 Currently, the only fixup is for the Geode machines using
929 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
931 Say Y if you want to enable the fixup. Currently, it's safe to
932 enable this option even if you don't need it.
933 Say N otherwise.
935 config MICROCODE
936 tristate "/dev/cpu/microcode - microcode support"
937 select FW_LOADER
938 ---help---
939 If you say Y here, you will be able to update the microcode on
940 certain Intel and AMD processors. The Intel support is for the
941 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
942 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
943 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
944 You will obviously need the actual microcode binary data itself
945 which is not shipped with the Linux kernel.
947 This option selects the general module only, you need to select
948 at least one vendor specific module as well.
950 To compile this driver as a module, choose M here: the
951 module will be called microcode.
953 config MICROCODE_INTEL
954 bool "Intel microcode patch loading support"
955 depends on MICROCODE
956 default MICROCODE
957 select FW_LOADER
958 ---help---
959 This options enables microcode patch loading support for Intel
960 processors.
962 For latest news and information on obtaining all the required
963 Intel ingredients for this driver, check:
964 <http://www.urbanmyth.org/microcode/>.
966 config MICROCODE_AMD
967 bool "AMD microcode patch loading support"
968 depends on MICROCODE
969 select FW_LOADER
970 ---help---
971 If you select this option, microcode patch loading support for AMD
972 processors will be enabled.
974 config MICROCODE_OLD_INTERFACE
975 def_bool y
976 depends on MICROCODE
978 config X86_MSR
979 tristate "/dev/cpu/*/msr - Model-specific register support"
980 ---help---
981 This device gives privileged processes access to the x86
982 Model-Specific Registers (MSRs). It is a character device with
983 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
984 MSR accesses are directed to a specific CPU on multi-processor
985 systems.
987 config X86_CPUID
988 tristate "/dev/cpu/*/cpuid - CPU information support"
989 ---help---
990 This device gives processes access to the x86 CPUID instruction to
991 be executed on a specific processor. It is a character device
992 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
993 /dev/cpu/31/cpuid.
995 config X86_CPU_DEBUG
996 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
997 ---help---
998 If you select this option, this will provide various x86 CPUs
999 information through debugfs.
1001 choice
1002 prompt "High Memory Support"
1003 default HIGHMEM4G if !X86_NUMAQ
1004 default HIGHMEM64G if X86_NUMAQ
1005 depends on X86_32
1007 config NOHIGHMEM
1008 bool "off"
1009 depends on !X86_NUMAQ
1010 ---help---
1011 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1012 However, the address space of 32-bit x86 processors is only 4
1013 Gigabytes large. That means that, if you have a large amount of
1014 physical memory, not all of it can be "permanently mapped" by the
1015 kernel. The physical memory that's not permanently mapped is called
1016 "high memory".
1018 If you are compiling a kernel which will never run on a machine with
1019 more than 1 Gigabyte total physical RAM, answer "off" here (default
1020 choice and suitable for most users). This will result in a "3GB/1GB"
1021 split: 3GB are mapped so that each process sees a 3GB virtual memory
1022 space and the remaining part of the 4GB virtual memory space is used
1023 by the kernel to permanently map as much physical memory as
1024 possible.
1026 If the machine has between 1 and 4 Gigabytes physical RAM, then
1027 answer "4GB" here.
1029 If more than 4 Gigabytes is used then answer "64GB" here. This
1030 selection turns Intel PAE (Physical Address Extension) mode on.
1031 PAE implements 3-level paging on IA32 processors. PAE is fully
1032 supported by Linux, PAE mode is implemented on all recent Intel
1033 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1034 then the kernel will not boot on CPUs that don't support PAE!
1036 The actual amount of total physical memory will either be
1037 auto detected or can be forced by using a kernel command line option
1038 such as "mem=256M". (Try "man bootparam" or see the documentation of
1039 your boot loader (lilo or loadlin) about how to pass options to the
1040 kernel at boot time.)
1042 If unsure, say "off".
1044 config HIGHMEM4G
1045 bool "4GB"
1046 depends on !X86_NUMAQ
1047 ---help---
1048 Select this if you have a 32-bit processor and between 1 and 4
1049 gigabytes of physical RAM.
1051 config HIGHMEM64G
1052 bool "64GB"
1053 depends on !M386 && !M486
1054 select X86_PAE
1055 ---help---
1056 Select this if you have a 32-bit processor and more than 4
1057 gigabytes of physical RAM.
1059 endchoice
1061 choice
1062 depends on EXPERIMENTAL
1063 prompt "Memory split" if EMBEDDED
1064 default VMSPLIT_3G
1065 depends on X86_32
1066 ---help---
1067 Select the desired split between kernel and user memory.
1069 If the address range available to the kernel is less than the
1070 physical memory installed, the remaining memory will be available
1071 as "high memory". Accessing high memory is a little more costly
1072 than low memory, as it needs to be mapped into the kernel first.
1073 Note that increasing the kernel address space limits the range
1074 available to user programs, making the address space there
1075 tighter. Selecting anything other than the default 3G/1G split
1076 will also likely make your kernel incompatible with binary-only
1077 kernel modules.
1079 If you are not absolutely sure what you are doing, leave this
1080 option alone!
1082 config VMSPLIT_3G
1083 bool "3G/1G user/kernel split"
1084 config VMSPLIT_3G_OPT
1085 depends on !X86_PAE
1086 bool "3G/1G user/kernel split (for full 1G low memory)"
1087 config VMSPLIT_2G
1088 bool "2G/2G user/kernel split"
1089 config VMSPLIT_2G_OPT
1090 depends on !X86_PAE
1091 bool "2G/2G user/kernel split (for full 2G low memory)"
1092 config VMSPLIT_1G
1093 bool "1G/3G user/kernel split"
1094 endchoice
1096 config PAGE_OFFSET
1097 hex
1098 default 0xB0000000 if VMSPLIT_3G_OPT
1099 default 0x80000000 if VMSPLIT_2G
1100 default 0x78000000 if VMSPLIT_2G_OPT
1101 default 0x40000000 if VMSPLIT_1G
1102 default 0xC0000000
1103 depends on X86_32
1105 config HIGHMEM
1106 def_bool y
1107 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1109 config X86_PAE
1110 bool "PAE (Physical Address Extension) Support"
1111 depends on X86_32 && !HIGHMEM4G
1112 ---help---
1113 PAE is required for NX support, and furthermore enables
1114 larger swapspace support for non-overcommit purposes. It
1115 has the cost of more pagetable lookup overhead, and also
1116 consumes more pagetable space per process.
1118 config ARCH_PHYS_ADDR_T_64BIT
1119 def_bool X86_64 || X86_PAE
1121 config DIRECT_GBPAGES
1122 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1123 default y
1124 depends on X86_64
1125 ---help---
1126 Allow the kernel linear mapping to use 1GB pages on CPUs that
1127 support it. This can improve the kernel's performance a tiny bit by
1128 reducing TLB pressure. If in doubt, say "Y".
1130 # Common NUMA Features
1131 config NUMA
1132 bool "Numa Memory Allocation and Scheduler Support"
1133 depends on SMP
1134 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1135 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1136 ---help---
1137 Enable NUMA (Non Uniform Memory Access) support.
1139 The kernel will try to allocate memory used by a CPU on the
1140 local memory controller of the CPU and add some more
1141 NUMA awareness to the kernel.
1143 For 64-bit this is recommended if the system is Intel Core i7
1144 (or later), AMD Opteron, or EM64T NUMA.
1146 For 32-bit this is only needed on (rare) 32-bit-only platforms
1147 that support NUMA topologies, such as NUMAQ / Summit, or if you
1148 boot a 32-bit kernel on a 64-bit NUMA platform.
1150 Otherwise, you should say N.
1152 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1153 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1155 config K8_NUMA
1156 def_bool y
1157 prompt "Old style AMD Opteron NUMA detection"
1158 depends on X86_64 && NUMA && PCI
1159 ---help---
1160 Enable K8 NUMA node topology detection. You should say Y here if
1161 you have a multi processor AMD K8 system. This uses an old
1162 method to read the NUMA configuration directly from the builtin
1163 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1164 instead, which also takes priority if both are compiled in.
1166 config X86_64_ACPI_NUMA
1167 def_bool y
1168 prompt "ACPI NUMA detection"
1169 depends on X86_64 && NUMA && ACPI && PCI
1170 select ACPI_NUMA
1171 ---help---
1172 Enable ACPI SRAT based node topology detection.
1174 # Some NUMA nodes have memory ranges that span
1175 # other nodes. Even though a pfn is valid and
1176 # between a node's start and end pfns, it may not
1177 # reside on that node. See memmap_init_zone()
1178 # for details.
1179 config NODES_SPAN_OTHER_NODES
1180 def_bool y
1181 depends on X86_64_ACPI_NUMA
1183 config NUMA_EMU
1184 bool "NUMA emulation"
1185 depends on X86_64 && NUMA
1186 ---help---
1187 Enable NUMA emulation. A flat machine will be split
1188 into virtual nodes when booted with "numa=fake=N", where N is the
1189 number of nodes. This is only useful for debugging.
1191 config NODES_SHIFT
1192 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1193 range 1 9
1194 default "9" if MAXSMP
1195 default "6" if X86_64
1196 default "4" if X86_NUMAQ
1197 default "3"
1198 depends on NEED_MULTIPLE_NODES
1199 ---help---
1200 Specify the maximum number of NUMA Nodes available on the target
1201 system. Increases memory reserved to accommodate various tables.
1203 config HAVE_ARCH_BOOTMEM
1204 def_bool y
1205 depends on X86_32 && NUMA
1207 config ARCH_HAVE_MEMORY_PRESENT
1208 def_bool y
1209 depends on X86_32 && DISCONTIGMEM
1211 config NEED_NODE_MEMMAP_SIZE
1212 def_bool y
1213 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1215 config HAVE_ARCH_ALLOC_REMAP
1216 def_bool y
1217 depends on X86_32 && NUMA
1219 config ARCH_FLATMEM_ENABLE
1220 def_bool y
1221 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1223 config ARCH_DISCONTIGMEM_ENABLE
1224 def_bool y
1225 depends on NUMA && X86_32
1227 config ARCH_DISCONTIGMEM_DEFAULT
1228 def_bool y
1229 depends on NUMA && X86_32
1231 config ARCH_SPARSEMEM_DEFAULT
1232 def_bool y
1233 depends on X86_64
1235 config ARCH_SPARSEMEM_ENABLE
1236 def_bool y
1237 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1238 select SPARSEMEM_STATIC if X86_32
1239 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1241 config ARCH_SELECT_MEMORY_MODEL
1242 def_bool y
1243 depends on ARCH_SPARSEMEM_ENABLE
1245 config ARCH_MEMORY_PROBE
1246 def_bool X86_64
1247 depends on MEMORY_HOTPLUG
1249 source "mm/Kconfig"
1251 config HIGHPTE
1252 bool "Allocate 3rd-level pagetables from highmem"
1253 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1254 ---help---
1255 The VM uses one page table entry for each page of physical memory.
1256 For systems with a lot of RAM, this can be wasteful of precious
1257 low memory. Setting this option will put user-space page table
1258 entries in high memory.
1260 config X86_CHECK_BIOS_CORRUPTION
1261 bool "Check for low memory corruption"
1262 ---help---
1263 Periodically check for memory corruption in low memory, which
1264 is suspected to be caused by BIOS. Even when enabled in the
1265 configuration, it is disabled at runtime. Enable it by
1266 setting "memory_corruption_check=1" on the kernel command
1267 line. By default it scans the low 64k of memory every 60
1268 seconds; see the memory_corruption_check_size and
1269 memory_corruption_check_period parameters in
1270 Documentation/kernel-parameters.txt to adjust this.
1272 When enabled with the default parameters, this option has
1273 almost no overhead, as it reserves a relatively small amount
1274 of memory and scans it infrequently. It both detects corruption
1275 and prevents it from affecting the running system.
1277 It is, however, intended as a diagnostic tool; if repeatable
1278 BIOS-originated corruption always affects the same memory,
1279 you can use memmap= to prevent the kernel from using that
1280 memory.
1282 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1283 bool "Set the default setting of memory_corruption_check"
1284 depends on X86_CHECK_BIOS_CORRUPTION
1285 default y
1286 ---help---
1287 Set whether the default state of memory_corruption_check is
1288 on or off.
1290 config X86_RESERVE_LOW_64K
1291 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1292 default y
1293 ---help---
1294 Reserve the first 64K of physical RAM on BIOSes that are known
1295 to potentially corrupt that memory range. A numbers of BIOSes are
1296 known to utilize this area during suspend/resume, so it must not
1297 be used by the kernel.
1299 Set this to N if you are absolutely sure that you trust the BIOS
1300 to get all its memory reservations and usages right.
1302 If you have doubts about the BIOS (e.g. suspend/resume does not
1303 work or there's kernel crashes after certain hardware hotplug
1304 events) and it's not AMI or Phoenix, then you might want to enable
1305 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1306 corruption patterns.
1308 Say Y if unsure.
1310 config MATH_EMULATION
1311 bool
1312 prompt "Math emulation" if X86_32
1313 ---help---
1314 Linux can emulate a math coprocessor (used for floating point
1315 operations) if you don't have one. 486DX and Pentium processors have
1316 a math coprocessor built in, 486SX and 386 do not, unless you added
1317 a 487DX or 387, respectively. (The messages during boot time can
1318 give you some hints here ["man dmesg"].) Everyone needs either a
1319 coprocessor or this emulation.
1321 If you don't have a math coprocessor, you need to say Y here; if you
1322 say Y here even though you have a coprocessor, the coprocessor will
1323 be used nevertheless. (This behavior can be changed with the kernel
1324 command line option "no387", which comes handy if your coprocessor
1325 is broken. Try "man bootparam" or see the documentation of your boot
1326 loader (lilo or loadlin) about how to pass options to the kernel at
1327 boot time.) This means that it is a good idea to say Y here if you
1328 intend to use this kernel on different machines.
1330 More information about the internals of the Linux math coprocessor
1331 emulation can be found in <file:arch/x86/math-emu/README>.
1333 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1334 kernel, it won't hurt.
1336 config MTRR
1337 bool "MTRR (Memory Type Range Register) support"
1338 ---help---
1339 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1340 the Memory Type Range Registers (MTRRs) may be used to control
1341 processor access to memory ranges. This is most useful if you have
1342 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1343 allows bus write transfers to be combined into a larger transfer
1344 before bursting over the PCI/AGP bus. This can increase performance
1345 of image write operations 2.5 times or more. Saying Y here creates a
1346 /proc/mtrr file which may be used to manipulate your processor's
1347 MTRRs. Typically the X server should use this.
1349 This code has a reasonably generic interface so that similar
1350 control registers on other processors can be easily supported
1351 as well:
1353 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1354 Registers (ARRs) which provide a similar functionality to MTRRs. For
1355 these, the ARRs are used to emulate the MTRRs.
1356 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1357 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1358 write-combining. All of these processors are supported by this code
1359 and it makes sense to say Y here if you have one of them.
1361 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1362 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1363 can lead to all sorts of problems, so it's good to say Y here.
1365 You can safely say Y even if your machine doesn't have MTRRs, you'll
1366 just add about 9 KB to your kernel.
1368 See <file:Documentation/x86/mtrr.txt> for more information.
1370 config MTRR_SANITIZER
1371 def_bool y
1372 prompt "MTRR cleanup support"
1373 depends on MTRR
1374 ---help---
1375 Convert MTRR layout from continuous to discrete, so X drivers can
1376 add writeback entries.
1378 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1379 The largest mtrr entry size for a continuous block can be set with
1380 mtrr_chunk_size.
1382 If unsure, say Y.
1384 config MTRR_SANITIZER_ENABLE_DEFAULT
1385 int "MTRR cleanup enable value (0-1)"
1386 range 0 1
1387 default "0"
1388 depends on MTRR_SANITIZER
1389 ---help---
1390 Enable mtrr cleanup default value
1392 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1393 int "MTRR cleanup spare reg num (0-7)"
1394 range 0 7
1395 default "1"
1396 depends on MTRR_SANITIZER
1397 ---help---
1398 mtrr cleanup spare entries default, it can be changed via
1399 mtrr_spare_reg_nr=N on the kernel command line.
1401 config X86_PAT
1402 bool
1403 prompt "x86 PAT support"
1404 depends on MTRR
1405 ---help---
1406 Use PAT attributes to setup page level cache control.
1408 PATs are the modern equivalents of MTRRs and are much more
1409 flexible than MTRRs.
1411 Say N here if you see bootup problems (boot crash, boot hang,
1412 spontaneous reboots) or a non-working video driver.
1414 If unsure, say Y.
1416 config EFI
1417 bool "EFI runtime service support"
1418 depends on ACPI
1419 ---help---
1420 This enables the kernel to use EFI runtime services that are
1421 available (such as the EFI variable services).
1423 This option is only useful on systems that have EFI firmware.
1424 In addition, you should use the latest ELILO loader available
1425 at <http://elilo.sourceforge.net> in order to take advantage
1426 of EFI runtime services. However, even with this option, the
1427 resultant kernel should continue to boot on existing non-EFI
1428 platforms.
1430 config SECCOMP
1431 def_bool y
1432 prompt "Enable seccomp to safely compute untrusted bytecode"
1433 ---help---
1434 This kernel feature is useful for number crunching applications
1435 that may need to compute untrusted bytecode during their
1436 execution. By using pipes or other transports made available to
1437 the process as file descriptors supporting the read/write
1438 syscalls, it's possible to isolate those applications in
1439 their own address space using seccomp. Once seccomp is
1440 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1441 and the task is only allowed to execute a few safe syscalls
1442 defined by each seccomp mode.
1444 If unsure, say Y. Only embedded should say N here.
1446 config CC_STACKPROTECTOR_ALL
1447 bool
1449 config CC_STACKPROTECTOR
1450 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1451 select CC_STACKPROTECTOR_ALL
1452 ---help---
1453 This option turns on the -fstack-protector GCC feature. This
1454 feature puts, at the beginning of functions, a canary value on
1455 the stack just before the return address, and validates
1456 the value just before actually returning. Stack based buffer
1457 overflows (that need to overwrite this return address) now also
1458 overwrite the canary, which gets detected and the attack is then
1459 neutralized via a kernel panic.
1461 This feature requires gcc version 4.2 or above, or a distribution
1462 gcc with the feature backported. Older versions are automatically
1463 detected and for those versions, this configuration option is
1464 ignored. (and a warning is printed during bootup)
1466 source kernel/Kconfig.hz
1468 config KEXEC
1469 bool "kexec system call"
1470 ---help---
1471 kexec is a system call that implements the ability to shutdown your
1472 current kernel, and to start another kernel. It is like a reboot
1473 but it is independent of the system firmware. And like a reboot
1474 you can start any kernel with it, not just Linux.
1476 The name comes from the similarity to the exec system call.
1478 It is an ongoing process to be certain the hardware in a machine
1479 is properly shutdown, so do not be surprised if this code does not
1480 initially work for you. It may help to enable device hotplugging
1481 support. As of this writing the exact hardware interface is
1482 strongly in flux, so no good recommendation can be made.
1484 config CRASH_DUMP
1485 bool "kernel crash dumps"
1486 depends on X86_64 || (X86_32 && HIGHMEM)
1487 ---help---
1488 Generate crash dump after being started by kexec.
1489 This should be normally only set in special crash dump kernels
1490 which are loaded in the main kernel with kexec-tools into
1491 a specially reserved region and then later executed after
1492 a crash by kdump/kexec. The crash dump kernel must be compiled
1493 to a memory address not used by the main kernel or BIOS using
1494 PHYSICAL_START, or it must be built as a relocatable image
1495 (CONFIG_RELOCATABLE=y).
1496 For more details see Documentation/kdump/kdump.txt
1498 config KEXEC_JUMP
1499 bool "kexec jump (EXPERIMENTAL)"
1500 depends on EXPERIMENTAL
1501 depends on KEXEC && HIBERNATION
1502 ---help---
1503 Jump between original kernel and kexeced kernel and invoke
1504 code in physical address mode via KEXEC
1506 config PHYSICAL_START
1507 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1508 default "0x1000000"
1509 ---help---
1510 This gives the physical address where the kernel is loaded.
1512 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1513 bzImage will decompress itself to above physical address and
1514 run from there. Otherwise, bzImage will run from the address where
1515 it has been loaded by the boot loader and will ignore above physical
1516 address.
1518 In normal kdump cases one does not have to set/change this option
1519 as now bzImage can be compiled as a completely relocatable image
1520 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1521 address. This option is mainly useful for the folks who don't want
1522 to use a bzImage for capturing the crash dump and want to use a
1523 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1524 to be specifically compiled to run from a specific memory area
1525 (normally a reserved region) and this option comes handy.
1527 So if you are using bzImage for capturing the crash dump,
1528 leave the value here unchanged to 0x1000000 and set
1529 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1530 for capturing the crash dump change this value to start of
1531 the reserved region. In other words, it can be set based on
1532 the "X" value as specified in the "crashkernel=YM@XM"
1533 command line boot parameter passed to the panic-ed
1534 kernel. Please take a look at Documentation/kdump/kdump.txt
1535 for more details about crash dumps.
1537 Usage of bzImage for capturing the crash dump is recommended as
1538 one does not have to build two kernels. Same kernel can be used
1539 as production kernel and capture kernel. Above option should have
1540 gone away after relocatable bzImage support is introduced. But it
1541 is present because there are users out there who continue to use
1542 vmlinux for dump capture. This option should go away down the
1543 line.
1545 Don't change this unless you know what you are doing.
1547 config RELOCATABLE
1548 bool "Build a relocatable kernel"
1549 default y
1550 ---help---
1551 This builds a kernel image that retains relocation information
1552 so it can be loaded someplace besides the default 1MB.
1553 The relocations tend to make the kernel binary about 10% larger,
1554 but are discarded at runtime.
1556 One use is for the kexec on panic case where the recovery kernel
1557 must live at a different physical address than the primary
1558 kernel.
1560 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1561 it has been loaded at and the compile time physical address
1562 (CONFIG_PHYSICAL_START) is ignored.
1564 # Relocation on x86-32 needs some additional build support
1565 config X86_NEED_RELOCS
1566 def_bool y
1567 depends on X86_32 && RELOCATABLE
1569 config PHYSICAL_ALIGN
1570 hex
1571 prompt "Alignment value to which kernel should be aligned" if X86_32
1572 default "0x1000000"
1573 range 0x2000 0x1000000
1574 ---help---
1575 This value puts the alignment restrictions on physical address
1576 where kernel is loaded and run from. Kernel is compiled for an
1577 address which meets above alignment restriction.
1579 If bootloader loads the kernel at a non-aligned address and
1580 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1581 address aligned to above value and run from there.
1583 If bootloader loads the kernel at a non-aligned address and
1584 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1585 load address and decompress itself to the address it has been
1586 compiled for and run from there. The address for which kernel is
1587 compiled already meets above alignment restrictions. Hence the
1588 end result is that kernel runs from a physical address meeting
1589 above alignment restrictions.
1591 Don't change this unless you know what you are doing.
1593 config HOTPLUG_CPU
1594 bool "Support for hot-pluggable CPUs"
1595 depends on SMP && HOTPLUG
1596 ---help---
1597 Say Y here to allow turning CPUs off and on. CPUs can be
1598 controlled through /sys/devices/system/cpu.
1599 ( Note: power management support will enable this option
1600 automatically on SMP systems. )
1601 Say N if you want to disable CPU hotplug.
1603 config COMPAT_VDSO
1604 def_bool y
1605 prompt "Compat VDSO support"
1606 depends on X86_32 || IA32_EMULATION
1607 ---help---
1608 Map the 32-bit VDSO to the predictable old-style address too.
1609 ---help---
1610 Say N here if you are running a sufficiently recent glibc
1611 version (2.3.3 or later), to remove the high-mapped
1612 VDSO mapping and to exclusively use the randomized VDSO.
1614 If unsure, say Y.
1616 config CMDLINE_BOOL
1617 bool "Built-in kernel command line"
1618 default n
1619 ---help---
1620 Allow for specifying boot arguments to the kernel at
1621 build time. On some systems (e.g. embedded ones), it is
1622 necessary or convenient to provide some or all of the
1623 kernel boot arguments with the kernel itself (that is,
1624 to not rely on the boot loader to provide them.)
1626 To compile command line arguments into the kernel,
1627 set this option to 'Y', then fill in the
1628 the boot arguments in CONFIG_CMDLINE.
1630 Systems with fully functional boot loaders (i.e. non-embedded)
1631 should leave this option set to 'N'.
1633 config CMDLINE
1634 string "Built-in kernel command string"
1635 depends on CMDLINE_BOOL
1636 default ""
1637 ---help---
1638 Enter arguments here that should be compiled into the kernel
1639 image and used at boot time. If the boot loader provides a
1640 command line at boot time, it is appended to this string to
1641 form the full kernel command line, when the system boots.
1643 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1644 change this behavior.
1646 In most cases, the command line (whether built-in or provided
1647 by the boot loader) should specify the device for the root
1648 file system.
1650 config CMDLINE_OVERRIDE
1651 bool "Built-in command line overrides boot loader arguments"
1652 default n
1653 depends on CMDLINE_BOOL
1654 ---help---
1655 Set this option to 'Y' to have the kernel ignore the boot loader
1656 command line, and use ONLY the built-in command line.
1658 This is used to work around broken boot loaders. This should
1659 be set to 'N' under normal conditions.
1661 endmenu
1663 config ARCH_ENABLE_MEMORY_HOTPLUG
1664 def_bool y
1665 depends on X86_64 || (X86_32 && HIGHMEM)
1667 config ARCH_ENABLE_MEMORY_HOTREMOVE
1668 def_bool y
1669 depends on MEMORY_HOTPLUG
1671 config HAVE_ARCH_EARLY_PFN_TO_NID
1672 def_bool X86_64
1673 depends on NUMA
1675 menu "Power management and ACPI options"
1677 config ARCH_HIBERNATION_HEADER
1678 def_bool y
1679 depends on X86_64 && HIBERNATION
1681 source "kernel/power/Kconfig"
1683 source "drivers/acpi/Kconfig"
1685 config X86_APM_BOOT
1686 bool
1687 default y
1688 depends on APM || APM_MODULE
1690 menuconfig APM
1691 tristate "APM (Advanced Power Management) BIOS support"
1692 depends on X86_32 && PM_SLEEP
1693 ---help---
1694 APM is a BIOS specification for saving power using several different
1695 techniques. This is mostly useful for battery powered laptops with
1696 APM compliant BIOSes. If you say Y here, the system time will be
1697 reset after a RESUME operation, the /proc/apm device will provide
1698 battery status information, and user-space programs will receive
1699 notification of APM "events" (e.g. battery status change).
1701 If you select "Y" here, you can disable actual use of the APM
1702 BIOS by passing the "apm=off" option to the kernel at boot time.
1704 Note that the APM support is almost completely disabled for
1705 machines with more than one CPU.
1707 In order to use APM, you will need supporting software. For location
1708 and more information, read <file:Documentation/power/pm.txt> and the
1709 Battery Powered Linux mini-HOWTO, available from
1710 <http://www.tldp.org/docs.html#howto>.
1712 This driver does not spin down disk drives (see the hdparm(8)
1713 manpage ("man 8 hdparm") for that), and it doesn't turn off
1714 VESA-compliant "green" monitors.
1716 This driver does not support the TI 4000M TravelMate and the ACER
1717 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1718 desktop machines also don't have compliant BIOSes, and this driver
1719 may cause those machines to panic during the boot phase.
1721 Generally, if you don't have a battery in your machine, there isn't
1722 much point in using this driver and you should say N. If you get
1723 random kernel OOPSes or reboots that don't seem to be related to
1724 anything, try disabling/enabling this option (or disabling/enabling
1725 APM in your BIOS).
1727 Some other things you should try when experiencing seemingly random,
1728 "weird" problems:
1730 1) make sure that you have enough swap space and that it is
1731 enabled.
1732 2) pass the "no-hlt" option to the kernel
1733 3) switch on floating point emulation in the kernel and pass
1734 the "no387" option to the kernel
1735 4) pass the "floppy=nodma" option to the kernel
1736 5) pass the "mem=4M" option to the kernel (thereby disabling
1737 all but the first 4 MB of RAM)
1738 6) make sure that the CPU is not over clocked.
1739 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1740 8) disable the cache from your BIOS settings
1741 9) install a fan for the video card or exchange video RAM
1742 10) install a better fan for the CPU
1743 11) exchange RAM chips
1744 12) exchange the motherboard.
1746 To compile this driver as a module, choose M here: the
1747 module will be called apm.
1749 if APM
1751 config APM_IGNORE_USER_SUSPEND
1752 bool "Ignore USER SUSPEND"
1753 ---help---
1754 This option will ignore USER SUSPEND requests. On machines with a
1755 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1756 series notebooks, it is necessary to say Y because of a BIOS bug.
1758 config APM_DO_ENABLE
1759 bool "Enable PM at boot time"
1760 ---help---
1761 Enable APM features at boot time. From page 36 of the APM BIOS
1762 specification: "When disabled, the APM BIOS does not automatically
1763 power manage devices, enter the Standby State, enter the Suspend
1764 State, or take power saving steps in response to CPU Idle calls."
1765 This driver will make CPU Idle calls when Linux is idle (unless this
1766 feature is turned off -- see "Do CPU IDLE calls", below). This
1767 should always save battery power, but more complicated APM features
1768 will be dependent on your BIOS implementation. You may need to turn
1769 this option off if your computer hangs at boot time when using APM
1770 support, or if it beeps continuously instead of suspending. Turn
1771 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1772 T400CDT. This is off by default since most machines do fine without
1773 this feature.
1775 config APM_CPU_IDLE
1776 bool "Make CPU Idle calls when idle"
1777 ---help---
1778 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1779 On some machines, this can activate improved power savings, such as
1780 a slowed CPU clock rate, when the machine is idle. These idle calls
1781 are made after the idle loop has run for some length of time (e.g.,
1782 333 mS). On some machines, this will cause a hang at boot time or
1783 whenever the CPU becomes idle. (On machines with more than one CPU,
1784 this option does nothing.)
1786 config APM_DISPLAY_BLANK
1787 bool "Enable console blanking using APM"
1788 ---help---
1789 Enable console blanking using the APM. Some laptops can use this to
1790 turn off the LCD backlight when the screen blanker of the Linux
1791 virtual console blanks the screen. Note that this is only used by
1792 the virtual console screen blanker, and won't turn off the backlight
1793 when using the X Window system. This also doesn't have anything to
1794 do with your VESA-compliant power-saving monitor. Further, this
1795 option doesn't work for all laptops -- it might not turn off your
1796 backlight at all, or it might print a lot of errors to the console,
1797 especially if you are using gpm.
1799 config APM_ALLOW_INTS
1800 bool "Allow interrupts during APM BIOS calls"
1801 ---help---
1802 Normally we disable external interrupts while we are making calls to
1803 the APM BIOS as a measure to lessen the effects of a badly behaving
1804 BIOS implementation. The BIOS should reenable interrupts if it
1805 needs to. Unfortunately, some BIOSes do not -- especially those in
1806 many of the newer IBM Thinkpads. If you experience hangs when you
1807 suspend, try setting this to Y. Otherwise, say N.
1809 endif # APM
1811 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1813 source "drivers/cpuidle/Kconfig"
1815 source "drivers/idle/Kconfig"
1817 endmenu
1820 menu "Bus options (PCI etc.)"
1822 config PCI
1823 bool "PCI support"
1824 default y
1825 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1826 ---help---
1827 Find out whether you have a PCI motherboard. PCI is the name of a
1828 bus system, i.e. the way the CPU talks to the other stuff inside
1829 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1830 VESA. If you have PCI, say Y, otherwise N.
1832 choice
1833 prompt "PCI access mode"
1834 depends on X86_32 && PCI
1835 default PCI_GOANY
1836 ---help---
1837 On PCI systems, the BIOS can be used to detect the PCI devices and
1838 determine their configuration. However, some old PCI motherboards
1839 have BIOS bugs and may crash if this is done. Also, some embedded
1840 PCI-based systems don't have any BIOS at all. Linux can also try to
1841 detect the PCI hardware directly without using the BIOS.
1843 With this option, you can specify how Linux should detect the
1844 PCI devices. If you choose "BIOS", the BIOS will be used,
1845 if you choose "Direct", the BIOS won't be used, and if you
1846 choose "MMConfig", then PCI Express MMCONFIG will be used.
1847 If you choose "Any", the kernel will try MMCONFIG, then the
1848 direct access method and falls back to the BIOS if that doesn't
1849 work. If unsure, go with the default, which is "Any".
1851 config PCI_GOBIOS
1852 bool "BIOS"
1854 config PCI_GOMMCONFIG
1855 bool "MMConfig"
1857 config PCI_GODIRECT
1858 bool "Direct"
1860 config PCI_GOOLPC
1861 bool "OLPC"
1862 depends on OLPC
1864 config PCI_GOANY
1865 bool "Any"
1867 endchoice
1869 config PCI_BIOS
1870 def_bool y
1871 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1873 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1874 config PCI_DIRECT
1875 def_bool y
1876 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1878 config PCI_MMCONFIG
1879 def_bool y
1880 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1882 config PCI_OLPC
1883 def_bool y
1884 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1886 config PCI_DOMAINS
1887 def_bool y
1888 depends on PCI
1890 config PCI_MMCONFIG
1891 bool "Support mmconfig PCI config space access"
1892 depends on X86_64 && PCI && ACPI
1894 config DMAR
1895 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1896 depends on PCI_MSI && ACPI && EXPERIMENTAL
1897 help
1898 DMA remapping (DMAR) devices support enables independent address
1899 translations for Direct Memory Access (DMA) from devices.
1900 These DMA remapping devices are reported via ACPI tables
1901 and include PCI device scope covered by these DMA
1902 remapping devices.
1904 config DMAR_DEFAULT_ON
1905 def_bool y
1906 prompt "Enable DMA Remapping Devices by default"
1907 depends on DMAR
1908 help
1909 Selecting this option will enable a DMAR device at boot time if
1910 one is found. If this option is not selected, DMAR support can
1911 be enabled by passing intel_iommu=on to the kernel. It is
1912 recommended you say N here while the DMAR code remains
1913 experimental.
1915 config DMAR_BROKEN_GFX_WA
1916 def_bool n
1917 prompt "Workaround broken graphics drivers (going away soon)"
1918 depends on DMAR
1919 ---help---
1920 Current Graphics drivers tend to use physical address
1921 for DMA and avoid using DMA APIs. Setting this config
1922 option permits the IOMMU driver to set a unity map for
1923 all the OS-visible memory. Hence the driver can continue
1924 to use physical addresses for DMA, at least until this
1925 option is removed in the 2.6.32 kernel.
1927 config DMAR_FLOPPY_WA
1928 def_bool y
1929 depends on DMAR
1930 ---help---
1931 Floppy disk drivers are known to bypass DMA API calls
1932 thereby failing to work when IOMMU is enabled. This
1933 workaround will setup a 1:1 mapping for the first
1934 16MiB to make floppy (an ISA device) work.
1936 config INTR_REMAP
1937 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1938 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1939 ---help---
1940 Supports Interrupt remapping for IO-APIC and MSI devices.
1941 To use x2apic mode in the CPU's which support x2APIC enhancements or
1942 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1944 source "drivers/pci/pcie/Kconfig"
1946 source "drivers/pci/Kconfig"
1948 # x86_64 have no ISA slots, but do have ISA-style DMA.
1949 config ISA_DMA_API
1950 def_bool y
1952 if X86_32
1954 config ISA
1955 bool "ISA support"
1956 ---help---
1957 Find out whether you have ISA slots on your motherboard. ISA is the
1958 name of a bus system, i.e. the way the CPU talks to the other stuff
1959 inside your box. Other bus systems are PCI, EISA, MicroChannel
1960 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1961 newer boards don't support it. If you have ISA, say Y, otherwise N.
1963 config EISA
1964 bool "EISA support"
1965 depends on ISA
1966 ---help---
1967 The Extended Industry Standard Architecture (EISA) bus was
1968 developed as an open alternative to the IBM MicroChannel bus.
1970 The EISA bus provided some of the features of the IBM MicroChannel
1971 bus while maintaining backward compatibility with cards made for
1972 the older ISA bus. The EISA bus saw limited use between 1988 and
1973 1995 when it was made obsolete by the PCI bus.
1975 Say Y here if you are building a kernel for an EISA-based machine.
1977 Otherwise, say N.
1979 source "drivers/eisa/Kconfig"
1981 config MCA
1982 bool "MCA support"
1983 ---help---
1984 MicroChannel Architecture is found in some IBM PS/2 machines and
1985 laptops. It is a bus system similar to PCI or ISA. See
1986 <file:Documentation/mca.txt> (and especially the web page given
1987 there) before attempting to build an MCA bus kernel.
1989 source "drivers/mca/Kconfig"
1991 config SCx200
1992 tristate "NatSemi SCx200 support"
1993 ---help---
1994 This provides basic support for National Semiconductor's
1995 (now AMD's) Geode processors. The driver probes for the
1996 PCI-IDs of several on-chip devices, so its a good dependency
1997 for other scx200_* drivers.
1999 If compiled as a module, the driver is named scx200.
2001 config SCx200HR_TIMER
2002 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2003 depends on SCx200 && GENERIC_TIME
2004 default y
2005 ---help---
2006 This driver provides a clocksource built upon the on-chip
2007 27MHz high-resolution timer. Its also a workaround for
2008 NSC Geode SC-1100's buggy TSC, which loses time when the
2009 processor goes idle (as is done by the scheduler). The
2010 other workaround is idle=poll boot option.
2012 config GEODE_MFGPT_TIMER
2013 def_bool y
2014 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
2015 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
2016 ---help---
2017 This driver provides a clock event source based on the MFGPT
2018 timer(s) in the CS5535 and CS5536 companion chip for the geode.
2019 MFGPTs have a better resolution and max interval than the
2020 generic PIT, and are suitable for use as high-res timers.
2022 config OLPC
2023 bool "One Laptop Per Child support"
2024 default n
2025 ---help---
2026 Add support for detecting the unique features of the OLPC
2027 XO hardware.
2029 endif # X86_32
2031 config K8_NB
2032 def_bool y
2033 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2035 source "drivers/pcmcia/Kconfig"
2037 source "drivers/pci/hotplug/Kconfig"
2039 endmenu
2042 menu "Executable file formats / Emulations"
2044 source "fs/Kconfig.binfmt"
2046 config IA32_EMULATION
2047 bool "IA32 Emulation"
2048 depends on X86_64
2049 select COMPAT_BINFMT_ELF
2050 ---help---
2051 Include code to run 32-bit programs under a 64-bit kernel. You should
2052 likely turn this on, unless you're 100% sure that you don't have any
2053 32-bit programs left.
2055 config IA32_AOUT
2056 tristate "IA32 a.out support"
2057 depends on IA32_EMULATION
2058 ---help---
2059 Support old a.out binaries in the 32bit emulation.
2061 config COMPAT
2062 def_bool y
2063 depends on IA32_EMULATION
2065 config COMPAT_FOR_U64_ALIGNMENT
2066 def_bool COMPAT
2067 depends on X86_64
2069 config SYSVIPC_COMPAT
2070 def_bool y
2071 depends on COMPAT && SYSVIPC
2073 endmenu
2076 config HAVE_ATOMIC_IOMAP
2077 def_bool y
2078 depends on X86_32
2080 source "net/Kconfig"
2082 source "drivers/Kconfig"
2084 source "drivers/firmware/Kconfig"
2086 source "fs/Kconfig"
2088 source "arch/x86/Kconfig.debug"
2090 source "security/Kconfig"
2092 source "crypto/Kconfig"
2094 source "arch/x86/kvm/Kconfig"
2096 source "lib/Kconfig"