| blob | 1042d69b267d4489e78365b27ec158d10d06d0c7 |
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_IOREMAP_PROT
28 select HAVE_KPROBES
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
37 select HAVE_KVM
38 select HAVE_ARCH_KGDB
39 select HAVE_ARCH_TRACEHOOK
40 select HAVE_GENERIC_DMA_COHERENT if X86_32
41 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 select USER_STACKTRACE_SUPPORT
44 config ARCH_DEFCONFIG
45 string
46 default "arch/x86/configs/i386_defconfig" if X86_32
47 default "arch/x86/configs/x86_64_defconfig" if X86_64
49 config GENERIC_TIME
50 def_bool y
52 config GENERIC_CMOS_UPDATE
53 def_bool y
55 config CLOCKSOURCE_WATCHDOG
56 def_bool y
58 config GENERIC_CLOCKEVENTS
59 def_bool y
61 config GENERIC_CLOCKEVENTS_BROADCAST
62 def_bool y
63 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
65 config LOCKDEP_SUPPORT
66 def_bool y
68 config STACKTRACE_SUPPORT
69 def_bool y
71 config HAVE_LATENCYTOP_SUPPORT
72 def_bool y
74 config FAST_CMPXCHG_LOCAL
75 bool
76 default y
78 config MMU
79 def_bool y
81 config ZONE_DMA
82 def_bool y
84 config SBUS
85 bool
87 config GENERIC_ISA_DMA
88 def_bool y
90 config GENERIC_IOMAP
91 def_bool y
93 config GENERIC_BUG
94 def_bool y
95 depends on BUG
96 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
98 config GENERIC_BUG_RELATIVE_POINTERS
99 bool
101 config GENERIC_HWEIGHT
102 def_bool y
104 config GENERIC_GPIO
105 bool
107 config ARCH_MAY_HAVE_PC_FDC
108 def_bool y
110 config RWSEM_GENERIC_SPINLOCK
111 def_bool !X86_XADD
113 config RWSEM_XCHGADD_ALGORITHM
114 def_bool X86_XADD
116 config ARCH_HAS_CPU_IDLE_WAIT
117 def_bool y
119 config GENERIC_CALIBRATE_DELAY
120 def_bool y
122 config GENERIC_TIME_VSYSCALL
123 bool
124 default X86_64
126 config ARCH_HAS_CPU_RELAX
127 def_bool y
129 config ARCH_HAS_DEFAULT_IDLE
130 def_bool y
132 config ARCH_HAS_CACHE_LINE_SIZE
133 def_bool y
135 config HAVE_SETUP_PER_CPU_AREA
136 def_bool y
138 config HAVE_CPUMASK_OF_CPU_MAP
139 def_bool X86_64_SMP
141 config ARCH_HIBERNATION_POSSIBLE
142 def_bool y
144 config ARCH_SUSPEND_POSSIBLE
145 def_bool y
147 config ZONE_DMA32
148 bool
149 default X86_64
151 config ARCH_POPULATES_NODE_MAP
152 def_bool y
154 config AUDIT_ARCH
155 bool
156 default X86_64
158 config ARCH_SUPPORTS_OPTIMIZED_INLINING
159 def_bool y
161 # Use the generic interrupt handling code in kernel/irq/:
162 config GENERIC_HARDIRQS
163 bool
164 default y
166 config GENERIC_IRQ_PROBE
167 bool
168 default y
170 config GENERIC_PENDING_IRQ
171 bool
172 depends on GENERIC_HARDIRQS && SMP
173 default y
175 config USE_GENERIC_SMP_HELPERS
176 def_bool y
177 depends on SMP
179 config X86_32_SMP
180 def_bool y
181 depends on X86_32 && SMP
183 config X86_64_SMP
184 def_bool y
185 depends on X86_64 && SMP
187 config X86_HT
188 bool
189 depends on SMP
190 default y
192 config X86_TRAMPOLINE
193 bool
194 depends on SMP || (64BIT && ACPI_SLEEP)
195 default y
197 config X86_32_LAZY_GS
198 def_bool y
199 depends on X86_32 && !CC_STACKPROTECTOR
201 config KTIME_SCALAR
202 def_bool X86_32
203 source "init/Kconfig"
204 source "kernel/Kconfig.freezer"
206 menu "Processor type and features"
208 source "kernel/time/Kconfig"
210 config SMP
211 bool "Symmetric multi-processing support"
212 ---help---
213 This enables support for systems with more than one CPU. If you have
214 a system with only one CPU, like most personal computers, say N. If
215 you have a system with more than one CPU, say Y.
217 If you say N here, the kernel will run on single and multiprocessor
218 machines, but will use only one CPU of a multiprocessor machine. If
219 you say Y here, the kernel will run on many, but not all,
220 singleprocessor machines. On a singleprocessor machine, the kernel
221 will run faster if you say N here.
223 Note that if you say Y here and choose architecture "586" or
224 "Pentium" under "Processor family", the kernel will not work on 486
225 architectures. Similarly, multiprocessor kernels for the "PPro"
226 architecture may not work on all Pentium based boards.
228 People using multiprocessor machines who say Y here should also say
229 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
230 Management" code will be disabled if you say Y here.
232 See also <file:Documentation/i386/IO-APIC.txt>,
233 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
234 <http://www.tldp.org/docs.html#howto>.
236 If you don't know what to do here, say N.
238 config SPARSE_IRQ
239 bool "Support sparse irq numbering"
240 depends on PCI_MSI || HT_IRQ
241 ---help---
242 This enables support for sparse irqs. This is useful for distro
243 kernels that want to define a high CONFIG_NR_CPUS value but still
244 want to have low kernel memory footprint on smaller machines.
246 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
247 out the irq_desc[] array in a more NUMA-friendly way. )
249 If you don't know what to do here, say N.
251 config NUMA_MIGRATE_IRQ_DESC
252 bool "Move irq desc when changing irq smp_affinity"
253 depends on SPARSE_IRQ && NUMA
254 default n
255 ---help---
256 This enables moving irq_desc to cpu/node that irq will use handled.
258 If you don't know what to do here, say N.
260 config X86_MPPARSE
261 bool "Enable MPS table" if ACPI
262 default y
263 depends on X86_LOCAL_APIC
264 ---help---
265 For old smp systems that do not have proper acpi support. Newer systems
266 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
268 config X86_BIGSMP
269 bool "Support for big SMP systems with more than 8 CPUs"
270 depends on X86_32 && SMP
271 ---help---
272 This option is needed for the systems that have more than 8 CPUs
274 config X86_EXTENDED_PLATFORM
275 bool "Support for extended (non-PC) x86 platforms"
276 default y
277 ---help---
278 If you disable this option then the kernel will only support
279 standard PC platforms. (which covers the vast majority of
280 systems out there.)
282 If you enable this option then you'll be able to select a number
283 of non-PC x86 platforms.
285 If you have one of these systems, or if you want to build a
286 generic distribution kernel, say Y here - otherwise say N.
288 # This is an alphabetically sorted list of 64 bit extended platforms
289 # Please maintain the alphabetic order if and when there are additions
291 config X86_VSMP
292 bool "ScaleMP vSMP"
293 select PARAVIRT
294 depends on X86_64 && PCI
295 depends on X86_EXTENDED_PLATFORM
296 ---help---
297 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
298 supposed to run on these EM64T-based machines. Only choose this option
299 if you have one of these machines.
301 config X86_UV
302 bool "SGI Ultraviolet"
303 depends on X86_64
304 depends on X86_EXTENDED_PLATFORM
305 ---help---
306 This option is needed in order to support SGI Ultraviolet systems.
307 If you don't have one of these, you should say N here.
309 # Following is an alphabetically sorted list of 32 bit extended platforms
310 # Please maintain the alphabetic order if and when there are additions
312 config X86_ELAN
313 bool "AMD Elan"
314 depends on X86_32
315 depends on X86_EXTENDED_PLATFORM
316 ---help---
317 Select this for an AMD Elan processor.
319 Do not use this option for K6/Athlon/Opteron processors!
321 If unsure, choose "PC-compatible" instead.
323 config X86_RDC321X
324 bool "RDC R-321x SoC"
325 depends on X86_32
326 depends on X86_EXTENDED_PLATFORM
327 select M486
328 select X86_REBOOTFIXUPS
329 ---help---
330 This option is needed for RDC R-321x system-on-chip, also known
331 as R-8610-(G).
332 If you don't have one of these chips, you should say N here.
334 config X86_32_NON_STANDARD
335 bool "Support non-standard 32-bit SMP architectures"
336 depends on X86_32 && SMP
337 depends on X86_EXTENDED_PLATFORM
338 ---help---
339 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
340 subarchitectures. It is intended for a generic binary kernel.
341 if you select them all, kernel will probe it one by one. and will
342 fallback to default.
344 # Alphabetically sorted list of Non standard 32 bit platforms
346 config X86_NUMAQ
347 bool "NUMAQ (IBM/Sequent)"
348 depends on X86_32_NON_STANDARD
349 select NUMA
350 select X86_MPPARSE
351 ---help---
352 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
353 NUMA multiquad box. This changes the way that processors are
354 bootstrapped, and uses Clustered Logical APIC addressing mode instead
355 of Flat Logical. You will need a new lynxer.elf file to flash your
356 firmware with - send email to <Martin.Bligh@us.ibm.com>.
358 config X86_VISWS
359 bool "SGI 320/540 (Visual Workstation)"
360 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
361 depends on X86_32_NON_STANDARD
362 ---help---
363 The SGI Visual Workstation series is an IA32-based workstation
364 based on SGI systems chips with some legacy PC hardware attached.
366 Say Y here to create a kernel to run on the SGI 320 or 540.
368 A kernel compiled for the Visual Workstation will run on general
369 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
371 config X86_SUMMIT
372 bool "Summit/EXA (IBM x440)"
373 depends on X86_32_NON_STANDARD
374 ---help---
375 This option is needed for IBM systems that use the Summit/EXA chipset.
376 In particular, it is needed for the x440.
378 config X86_ES7000
379 bool "Unisys ES7000 IA32 series"
380 depends on X86_32_NON_STANDARD && X86_BIGSMP
381 ---help---
382 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
383 supposed to run on an IA32-based Unisys ES7000 system.
385 config X86_VOYAGER
386 bool "Voyager (NCR)"
387 depends on SMP && !PCI && BROKEN
388 depends on X86_32_NON_STANDARD
389 ---help---
390 Voyager is an MCA-based 32-way capable SMP architecture proprietary
391 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
393 *** WARNING ***
395 If you do not specifically know you have a Voyager based machine,
396 say N here, otherwise the kernel you build will not be bootable.
398 config SCHED_OMIT_FRAME_POINTER
399 def_bool y
400 prompt "Single-depth WCHAN output"
401 depends on X86
402 ---help---
403 Calculate simpler /proc/<PID>/wchan values. If this option
404 is disabled then wchan values will recurse back to the
405 caller function. This provides more accurate wchan values,
406 at the expense of slightly more scheduling overhead.
408 If in doubt, say "Y".
410 menuconfig PARAVIRT_GUEST
411 bool "Paravirtualized guest support"
412 ---help---
413 Say Y here to get to see options related to running Linux under
414 various hypervisors. This option alone does not add any kernel code.
416 If you say N, all options in this submenu will be skipped and disabled.
418 if PARAVIRT_GUEST
420 source "arch/x86/xen/Kconfig"
422 config VMI
423 bool "VMI Guest support"
424 select PARAVIRT
425 depends on X86_32
426 ---help---
427 VMI provides a paravirtualized interface to the VMware ESX server
428 (it could be used by other hypervisors in theory too, but is not
429 at the moment), by linking the kernel to a GPL-ed ROM module
430 provided by the hypervisor.
432 config KVM_CLOCK
433 bool "KVM paravirtualized clock"
434 select PARAVIRT
435 select PARAVIRT_CLOCK
436 ---help---
437 Turning on this option will allow you to run a paravirtualized clock
438 when running over the KVM hypervisor. Instead of relying on a PIT
439 (or probably other) emulation by the underlying device model, the host
440 provides the guest with timing infrastructure such as time of day, and
441 system time
443 config KVM_GUEST
444 bool "KVM Guest support"
445 select PARAVIRT
446 ---help---
447 This option enables various optimizations for running under the KVM
448 hypervisor.
450 source "arch/x86/lguest/Kconfig"
452 config PARAVIRT
453 bool "Enable paravirtualization code"
454 ---help---
455 This changes the kernel so it can modify itself when it is run
456 under a hypervisor, potentially improving performance significantly
457 over full virtualization. However, when run without a hypervisor
458 the kernel is theoretically slower and slightly larger.
460 config PARAVIRT_CLOCK
461 bool
462 default n
464 endif
466 config PARAVIRT_DEBUG
467 bool "paravirt-ops debugging"
468 depends on PARAVIRT && DEBUG_KERNEL
469 ---help---
470 Enable to debug paravirt_ops internals. Specifically, BUG if
471 a paravirt_op is missing when it is called.
473 config MEMTEST
474 bool "Memtest"
475 ---help---
476 This option adds a kernel parameter 'memtest', which allows memtest
477 to be set.
478 memtest=0, mean disabled; -- default
479 memtest=1, mean do 1 test pattern;
480 ...
481 memtest=4, mean do 4 test patterns.
482 If you are unsure how to answer this question, answer N.
484 config X86_SUMMIT_NUMA
485 def_bool y
486 depends on X86_32 && NUMA && X86_32_NON_STANDARD
488 config X86_CYCLONE_TIMER
489 def_bool y
490 depends on X86_32_NON_STANDARD
492 source "arch/x86/Kconfig.cpu"
494 config HPET_TIMER
495 def_bool X86_64
496 prompt "HPET Timer Support" if X86_32
497 ---help---
498 Use the IA-PC HPET (High Precision Event Timer) to manage
499 time in preference to the PIT and RTC, if a HPET is
500 present.
501 HPET is the next generation timer replacing legacy 8254s.
502 The HPET provides a stable time base on SMP
503 systems, unlike the TSC, but it is more expensive to access,
504 as it is off-chip. You can find the HPET spec at
505 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
507 You can safely choose Y here. However, HPET will only be
508 activated if the platform and the BIOS support this feature.
509 Otherwise the 8254 will be used for timing services.
511 Choose N to continue using the legacy 8254 timer.
513 config HPET_EMULATE_RTC
514 def_bool y
515 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
517 # Mark as embedded because too many people got it wrong.
518 # The code disables itself when not needed.
519 config DMI
520 default y
521 bool "Enable DMI scanning" if EMBEDDED
522 ---help---
523 Enabled scanning of DMI to identify machine quirks. Say Y
524 here unless you have verified that your setup is not
525 affected by entries in the DMI blacklist. Required by PNP
526 BIOS code.
528 config GART_IOMMU
529 bool "GART IOMMU support" if EMBEDDED
530 default y
531 select SWIOTLB
532 select AGP
533 depends on X86_64 && PCI
534 ---help---
535 Support for full DMA access of devices with 32bit memory access only
536 on systems with more than 3GB. This is usually needed for USB,
537 sound, many IDE/SATA chipsets and some other devices.
538 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
539 based hardware IOMMU and a software bounce buffer based IOMMU used
540 on Intel systems and as fallback.
541 The code is only active when needed (enough memory and limited
542 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
543 too.
545 config CALGARY_IOMMU
546 bool "IBM Calgary IOMMU support"
547 select SWIOTLB
548 depends on X86_64 && PCI && EXPERIMENTAL
549 ---help---
550 Support for hardware IOMMUs in IBM's xSeries x366 and x460
551 systems. Needed to run systems with more than 3GB of memory
552 properly with 32-bit PCI devices that do not support DAC
553 (Double Address Cycle). Calgary also supports bus level
554 isolation, where all DMAs pass through the IOMMU. This
555 prevents them from going anywhere except their intended
556 destination. This catches hard-to-find kernel bugs and
557 mis-behaving drivers and devices that do not use the DMA-API
558 properly to set up their DMA buffers. The IOMMU can be
559 turned off at boot time with the iommu=off parameter.
560 Normally the kernel will make the right choice by itself.
561 If unsure, say Y.
563 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
564 def_bool y
565 prompt "Should Calgary be enabled by default?"
566 depends on CALGARY_IOMMU
567 ---help---
568 Should Calgary be enabled by default? if you choose 'y', Calgary
569 will be used (if it exists). If you choose 'n', Calgary will not be
570 used even if it exists. If you choose 'n' and would like to use
571 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
572 If unsure, say Y.
574 config AMD_IOMMU
575 bool "AMD IOMMU support"
576 select SWIOTLB
577 select PCI_MSI
578 depends on X86_64 && PCI && ACPI
579 ---help---
580 With this option you can enable support for AMD IOMMU hardware in
581 your system. An IOMMU is a hardware component which provides
582 remapping of DMA memory accesses from devices. With an AMD IOMMU you
583 can isolate the the DMA memory of different devices and protect the
584 system from misbehaving device drivers or hardware.
586 You can find out if your system has an AMD IOMMU if you look into
587 your BIOS for an option to enable it or if you have an IVRS ACPI
588 table.
590 config AMD_IOMMU_STATS
591 bool "Export AMD IOMMU statistics to debugfs"
592 depends on AMD_IOMMU
593 select DEBUG_FS
594 ---help---
595 This option enables code in the AMD IOMMU driver to collect various
596 statistics about whats happening in the driver and exports that
597 information to userspace via debugfs.
598 If unsure, say N.
600 # need this always selected by IOMMU for the VIA workaround
601 config SWIOTLB
602 def_bool y if X86_64
603 ---help---
604 Support for software bounce buffers used on x86-64 systems
605 which don't have a hardware IOMMU (e.g. the current generation
606 of Intel's x86-64 CPUs). Using this PCI devices which can only
607 access 32-bits of memory can be used on systems with more than
608 3 GB of memory. If unsure, say Y.
610 config IOMMU_HELPER
611 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
613 config IOMMU_API
614 def_bool (AMD_IOMMU || DMAR)
616 config MAXSMP
617 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
618 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
619 select CPUMASK_OFFSTACK
620 default n
621 ---help---
622 Configure maximum number of CPUS and NUMA Nodes for this architecture.
623 If unsure, say N.
625 config NR_CPUS
626 int "Maximum number of CPUs" if SMP && !MAXSMP
627 range 2 512 if SMP && !MAXSMP
628 default "1" if !SMP
629 default "4096" if MAXSMP
630 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
631 default "8" if SMP
632 ---help---
633 This allows you to specify the maximum number of CPUs which this
634 kernel will support. The maximum supported value is 512 and the
635 minimum value which makes sense is 2.
637 This is purely to save memory - each supported CPU adds
638 approximately eight kilobytes to the kernel image.
640 config SCHED_SMT
641 bool "SMT (Hyperthreading) scheduler support"
642 depends on X86_HT
643 ---help---
644 SMT scheduler support improves the CPU scheduler's decision making
645 when dealing with Intel Pentium 4 chips with HyperThreading at a
646 cost of slightly increased overhead in some places. If unsure say
647 N here.
649 config SCHED_MC
650 def_bool y
651 prompt "Multi-core scheduler support"
652 depends on X86_HT
653 ---help---
654 Multi-core scheduler support improves the CPU scheduler's decision
655 making when dealing with multi-core CPU chips at a cost of slightly
656 increased overhead in some places. If unsure say N here.
658 source "kernel/Kconfig.preempt"
660 config X86_UP_APIC
661 bool "Local APIC support on uniprocessors"
662 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
663 ---help---
664 A local APIC (Advanced Programmable Interrupt Controller) is an
665 integrated interrupt controller in the CPU. If you have a single-CPU
666 system which has a processor with a local APIC, you can say Y here to
667 enable and use it. If you say Y here even though your machine doesn't
668 have a local APIC, then the kernel will still run with no slowdown at
669 all. The local APIC supports CPU-generated self-interrupts (timer,
670 performance counters), and the NMI watchdog which detects hard
671 lockups.
673 config X86_UP_IOAPIC
674 bool "IO-APIC support on uniprocessors"
675 depends on X86_UP_APIC
676 ---help---
677 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
678 SMP-capable replacement for PC-style interrupt controllers. Most
679 SMP systems and many recent uniprocessor systems have one.
681 If you have a single-CPU system with an IO-APIC, you can say Y here
682 to use it. If you say Y here even though your machine doesn't have
683 an IO-APIC, then the kernel will still run with no slowdown at all.
685 config X86_LOCAL_APIC
686 def_bool y
687 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
689 config X86_IO_APIC
690 def_bool y
691 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
693 config X86_VISWS_APIC
694 def_bool y
695 depends on X86_32 && X86_VISWS
697 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
698 bool "Reroute for broken boot IRQs"
699 default n
700 depends on X86_IO_APIC
701 ---help---
702 This option enables a workaround that fixes a source of
703 spurious interrupts. This is recommended when threaded
704 interrupt handling is used on systems where the generation of
705 superfluous "boot interrupts" cannot be disabled.
707 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
708 entry in the chipset's IO-APIC is masked (as, e.g. the RT
709 kernel does during interrupt handling). On chipsets where this
710 boot IRQ generation cannot be disabled, this workaround keeps
711 the original IRQ line masked so that only the equivalent "boot
712 IRQ" is delivered to the CPUs. The workaround also tells the
713 kernel to set up the IRQ handler on the boot IRQ line. In this
714 way only one interrupt is delivered to the kernel. Otherwise
715 the spurious second interrupt may cause the kernel to bring
716 down (vital) interrupt lines.
718 Only affects "broken" chipsets. Interrupt sharing may be
719 increased on these systems.
721 config X86_MCE
722 bool "Machine Check Exception"
723 ---help---
724 Machine Check Exception support allows the processor to notify the
725 kernel if it detects a problem (e.g. overheating, component failure).
726 The action the kernel takes depends on the severity of the problem,
727 ranging from a warning message on the console, to halting the machine.
728 Your processor must be a Pentium or newer to support this - check the
729 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
730 have a design flaw which leads to false MCE events - hence MCE is
731 disabled on all P5 processors, unless explicitly enabled with "mce"
732 as a boot argument. Similarly, if MCE is built in and creates a
733 problem on some new non-standard machine, you can boot with "nomce"
734 to disable it. MCE support simply ignores non-MCE processors like
735 the 386 and 486, so nearly everyone can say Y here.
737 config X86_MCE_INTEL
738 def_bool y
739 prompt "Intel MCE features"
740 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
741 ---help---
742 Additional support for intel specific MCE features such as
743 the thermal monitor.
745 config X86_MCE_AMD
746 def_bool y
747 prompt "AMD MCE features"
748 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
749 ---help---
750 Additional support for AMD specific MCE features such as
751 the DRAM Error Threshold.
753 config X86_MCE_NONFATAL
754 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
755 depends on X86_32 && X86_MCE
756 ---help---
757 Enabling this feature starts a timer that triggers every 5 seconds which
758 will look at the machine check registers to see if anything happened.
759 Non-fatal problems automatically get corrected (but still logged).
760 Disable this if you don't want to see these messages.
761 Seeing the messages this option prints out may be indicative of dying
762 or out-of-spec (ie, overclocked) hardware.
763 This option only does something on certain CPUs.
764 (AMD Athlon/Duron and Intel Pentium 4)
766 config X86_MCE_P4THERMAL
767 bool "check for P4 thermal throttling interrupt."
768 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
769 ---help---
770 Enabling this feature will cause a message to be printed when the P4
771 enters thermal throttling.
773 config VM86
774 bool "Enable VM86 support" if EMBEDDED
775 default y
776 depends on X86_32
777 ---help---
778 This option is required by programs like DOSEMU to run 16-bit legacy
779 code on X86 processors. It also may be needed by software like
780 XFree86 to initialize some video cards via BIOS. Disabling this
781 option saves about 6k.
783 config TOSHIBA
784 tristate "Toshiba Laptop support"
785 depends on X86_32
786 ---help---
787 This adds a driver to safely access the System Management Mode of
788 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
789 not work on models with a Phoenix BIOS. The System Management Mode
790 is used to set the BIOS and power saving options on Toshiba portables.
792 For information on utilities to make use of this driver see the
793 Toshiba Linux utilities web site at:
794 <http://www.buzzard.org.uk/toshiba/>.
796 Say Y if you intend to run this kernel on a Toshiba portable.
797 Say N otherwise.
799 config I8K
800 tristate "Dell laptop support"
801 ---help---
802 This adds a driver to safely access the System Management Mode
803 of the CPU on the Dell Inspiron 8000. The System Management Mode
804 is used to read cpu temperature and cooling fan status and to
805 control the fans on the I8K portables.
807 This driver has been tested only on the Inspiron 8000 but it may
808 also work with other Dell laptops. You can force loading on other
809 models by passing the parameter `force=1' to the module. Use at
810 your own risk.
812 For information on utilities to make use of this driver see the
813 I8K Linux utilities web site at:
814 <http://people.debian.org/~dz/i8k/>
816 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
817 Say N otherwise.
819 config X86_REBOOTFIXUPS
820 bool "Enable X86 board specific fixups for reboot"
821 depends on X86_32
822 ---help---
823 This enables chipset and/or board specific fixups to be done
824 in order to get reboot to work correctly. This is only needed on
825 some combinations of hardware and BIOS. The symptom, for which
826 this config is intended, is when reboot ends with a stalled/hung
827 system.
829 Currently, the only fixup is for the Geode machines using
830 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
832 Say Y if you want to enable the fixup. Currently, it's safe to
833 enable this option even if you don't need it.
834 Say N otherwise.
836 config MICROCODE
837 tristate "/dev/cpu/microcode - microcode support"
838 select FW_LOADER
839 ---help---
840 If you say Y here, you will be able to update the microcode on
841 certain Intel and AMD processors. The Intel support is for the
842 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
843 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
844 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
845 You will obviously need the actual microcode binary data itself
846 which is not shipped with the Linux kernel.
848 This option selects the general module only, you need to select
849 at least one vendor specific module as well.
851 To compile this driver as a module, choose M here: the
852 module will be called microcode.
854 config MICROCODE_INTEL
855 bool "Intel microcode patch loading support"
856 depends on MICROCODE
857 default MICROCODE
858 select FW_LOADER
859 ---help---
860 This options enables microcode patch loading support for Intel
861 processors.
863 For latest news and information on obtaining all the required
864 Intel ingredients for this driver, check:
865 <http://www.urbanmyth.org/microcode/>.
867 config MICROCODE_AMD
868 bool "AMD microcode patch loading support"
869 depends on MICROCODE
870 select FW_LOADER
871 ---help---
872 If you select this option, microcode patch loading support for AMD
873 processors will be enabled.
875 config MICROCODE_OLD_INTERFACE
876 def_bool y
877 depends on MICROCODE
879 config X86_MSR
880 tristate "/dev/cpu/*/msr - Model-specific register support"
881 ---help---
882 This device gives privileged processes access to the x86
883 Model-Specific Registers (MSRs). It is a character device with
884 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
885 MSR accesses are directed to a specific CPU on multi-processor
886 systems.
888 config X86_CPUID
889 tristate "/dev/cpu/*/cpuid - CPU information support"
890 ---help---
891 This device gives processes access to the x86 CPUID instruction to
892 be executed on a specific processor. It is a character device
893 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
894 /dev/cpu/31/cpuid.
896 choice
897 prompt "High Memory Support"
898 default HIGHMEM4G if !X86_NUMAQ
899 default HIGHMEM64G if X86_NUMAQ
900 depends on X86_32
902 config NOHIGHMEM
903 bool "off"
904 depends on !X86_NUMAQ
905 ---help---
906 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
907 However, the address space of 32-bit x86 processors is only 4
908 Gigabytes large. That means that, if you have a large amount of
909 physical memory, not all of it can be "permanently mapped" by the
910 kernel. The physical memory that's not permanently mapped is called
911 "high memory".
913 If you are compiling a kernel which will never run on a machine with
914 more than 1 Gigabyte total physical RAM, answer "off" here (default
915 choice and suitable for most users). This will result in a "3GB/1GB"
916 split: 3GB are mapped so that each process sees a 3GB virtual memory
917 space and the remaining part of the 4GB virtual memory space is used
918 by the kernel to permanently map as much physical memory as
919 possible.
921 If the machine has between 1 and 4 Gigabytes physical RAM, then
922 answer "4GB" here.
924 If more than 4 Gigabytes is used then answer "64GB" here. This
925 selection turns Intel PAE (Physical Address Extension) mode on.
926 PAE implements 3-level paging on IA32 processors. PAE is fully
927 supported by Linux, PAE mode is implemented on all recent Intel
928 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
929 then the kernel will not boot on CPUs that don't support PAE!
931 The actual amount of total physical memory will either be
932 auto detected or can be forced by using a kernel command line option
933 such as "mem=256M". (Try "man bootparam" or see the documentation of
934 your boot loader (lilo or loadlin) about how to pass options to the
935 kernel at boot time.)
937 If unsure, say "off".
939 config HIGHMEM4G
940 bool "4GB"
941 depends on !X86_NUMAQ
942 ---help---
943 Select this if you have a 32-bit processor and between 1 and 4
944 gigabytes of physical RAM.
946 config HIGHMEM64G
947 bool "64GB"
948 depends on !M386 && !M486
949 select X86_PAE
950 ---help---
951 Select this if you have a 32-bit processor and more than 4
952 gigabytes of physical RAM.
954 endchoice
956 choice
957 depends on EXPERIMENTAL
958 prompt "Memory split" if EMBEDDED
959 default VMSPLIT_3G
960 depends on X86_32
961 ---help---
962 Select the desired split between kernel and user memory.
964 If the address range available to the kernel is less than the
965 physical memory installed, the remaining memory will be available
966 as "high memory". Accessing high memory is a little more costly
967 than low memory, as it needs to be mapped into the kernel first.
968 Note that increasing the kernel address space limits the range
969 available to user programs, making the address space there
970 tighter. Selecting anything other than the default 3G/1G split
971 will also likely make your kernel incompatible with binary-only
972 kernel modules.
974 If you are not absolutely sure what you are doing, leave this
975 option alone!
977 config VMSPLIT_3G
978 bool "3G/1G user/kernel split"
979 config VMSPLIT_3G_OPT
980 depends on !X86_PAE
981 bool "3G/1G user/kernel split (for full 1G low memory)"
982 config VMSPLIT_2G
983 bool "2G/2G user/kernel split"
984 config VMSPLIT_2G_OPT
985 depends on !X86_PAE
986 bool "2G/2G user/kernel split (for full 2G low memory)"
987 config VMSPLIT_1G
988 bool "1G/3G user/kernel split"
989 endchoice
991 config PAGE_OFFSET
992 hex
993 default 0xB0000000 if VMSPLIT_3G_OPT
994 default 0x80000000 if VMSPLIT_2G
995 default 0x78000000 if VMSPLIT_2G_OPT
996 default 0x40000000 if VMSPLIT_1G
997 default 0xC0000000
998 depends on X86_32
1000 config HIGHMEM
1001 def_bool y
1002 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1004 config X86_PAE
1005 bool "PAE (Physical Address Extension) Support"
1006 depends on X86_32 && !HIGHMEM4G
1007 ---help---
1008 PAE is required for NX support, and furthermore enables
1009 larger swapspace support for non-overcommit purposes. It
1010 has the cost of more pagetable lookup overhead, and also
1011 consumes more pagetable space per process.
1013 config ARCH_PHYS_ADDR_T_64BIT
1014 def_bool X86_64 || X86_PAE
1016 config DIRECT_GBPAGES
1017 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1018 default y
1019 depends on X86_64
1020 ---help---
1021 Allow the kernel linear mapping to use 1GB pages on CPUs that
1022 support it. This can improve the kernel's performance a tiny bit by
1023 reducing TLB pressure. If in doubt, say "Y".
1025 # Common NUMA Features
1026 config NUMA
1027 bool "Numa Memory Allocation and Scheduler Support"
1028 depends on SMP
1029 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1030 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1031 ---help---
1032 Enable NUMA (Non Uniform Memory Access) support.
1034 The kernel will try to allocate memory used by a CPU on the
1035 local memory controller of the CPU and add some more
1036 NUMA awareness to the kernel.
1038 For 64-bit this is recommended if the system is Intel Core i7
1039 (or later), AMD Opteron, or EM64T NUMA.
1041 For 32-bit this is only needed on (rare) 32-bit-only platforms
1042 that support NUMA topologies, such as NUMAQ / Summit, or if you
1043 boot a 32-bit kernel on a 64-bit NUMA platform.
1045 Otherwise, you should say N.
1047 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1048 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1050 config K8_NUMA
1051 def_bool y
1052 prompt "Old style AMD Opteron NUMA detection"
1053 depends on X86_64 && NUMA && PCI
1054 ---help---
1055 Enable K8 NUMA node topology detection. You should say Y here if
1056 you have a multi processor AMD K8 system. This uses an old
1057 method to read the NUMA configuration directly from the builtin
1058 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1059 instead, which also takes priority if both are compiled in.
1061 config X86_64_ACPI_NUMA
1062 def_bool y
1063 prompt "ACPI NUMA detection"
1064 depends on X86_64 && NUMA && ACPI && PCI
1065 select ACPI_NUMA
1066 ---help---
1067 Enable ACPI SRAT based node topology detection.
1069 # Some NUMA nodes have memory ranges that span
1070 # other nodes. Even though a pfn is valid and
1071 # between a node's start and end pfns, it may not
1072 # reside on that node. See memmap_init_zone()
1073 # for details.
1074 config NODES_SPAN_OTHER_NODES
1075 def_bool y
1076 depends on X86_64_ACPI_NUMA
1078 config NUMA_EMU
1079 bool "NUMA emulation"
1080 depends on X86_64 && NUMA
1081 ---help---
1082 Enable NUMA emulation. A flat machine will be split
1083 into virtual nodes when booted with "numa=fake=N", where N is the
1084 number of nodes. This is only useful for debugging.
1086 config NODES_SHIFT
1087 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1088 range 1 9 if X86_64
1089 default "9" if MAXSMP
1090 default "6" if X86_64
1091 default "4" if X86_NUMAQ
1092 default "3"
1093 depends on NEED_MULTIPLE_NODES
1094 ---help---
1095 Specify the maximum number of NUMA Nodes available on the target
1096 system. Increases memory reserved to accomodate various tables.
1098 config HAVE_ARCH_BOOTMEM_NODE
1099 def_bool y
1100 depends on X86_32 && NUMA
1102 config ARCH_HAVE_MEMORY_PRESENT
1103 def_bool y
1104 depends on X86_32 && DISCONTIGMEM
1106 config NEED_NODE_MEMMAP_SIZE
1107 def_bool y
1108 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1110 config HAVE_ARCH_ALLOC_REMAP
1111 def_bool y
1112 depends on X86_32 && NUMA
1114 config ARCH_FLATMEM_ENABLE
1115 def_bool y
1116 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1118 config ARCH_DISCONTIGMEM_ENABLE
1119 def_bool y
1120 depends on NUMA && X86_32
1122 config ARCH_DISCONTIGMEM_DEFAULT
1123 def_bool y
1124 depends on NUMA && X86_32
1126 config ARCH_SPARSEMEM_DEFAULT
1127 def_bool y
1128 depends on X86_64
1130 config ARCH_SPARSEMEM_ENABLE
1131 def_bool y
1132 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1133 select SPARSEMEM_STATIC if X86_32
1134 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1136 config ARCH_SELECT_MEMORY_MODEL
1137 def_bool y
1138 depends on ARCH_SPARSEMEM_ENABLE
1140 config ARCH_MEMORY_PROBE
1141 def_bool X86_64
1142 depends on MEMORY_HOTPLUG
1144 source "mm/Kconfig"
1146 config HIGHPTE
1147 bool "Allocate 3rd-level pagetables from highmem"
1148 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1149 ---help---
1150 The VM uses one page table entry for each page of physical memory.
1151 For systems with a lot of RAM, this can be wasteful of precious
1152 low memory. Setting this option will put user-space page table
1153 entries in high memory.
1155 config X86_CHECK_BIOS_CORRUPTION
1156 bool "Check for low memory corruption"
1157 ---help---
1158 Periodically check for memory corruption in low memory, which
1159 is suspected to be caused by BIOS. Even when enabled in the
1160 configuration, it is disabled at runtime. Enable it by
1161 setting "memory_corruption_check=1" on the kernel command
1162 line. By default it scans the low 64k of memory every 60
1163 seconds; see the memory_corruption_check_size and
1164 memory_corruption_check_period parameters in
1165 Documentation/kernel-parameters.txt to adjust this.
1167 When enabled with the default parameters, this option has
1168 almost no overhead, as it reserves a relatively small amount
1169 of memory and scans it infrequently. It both detects corruption
1170 and prevents it from affecting the running system.
1172 It is, however, intended as a diagnostic tool; if repeatable
1173 BIOS-originated corruption always affects the same memory,
1174 you can use memmap= to prevent the kernel from using that
1175 memory.
1177 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1178 bool "Set the default setting of memory_corruption_check"
1179 depends on X86_CHECK_BIOS_CORRUPTION
1180 default y
1181 ---help---
1182 Set whether the default state of memory_corruption_check is
1183 on or off.
1185 config X86_RESERVE_LOW_64K
1186 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1187 default y
1188 ---help---
1189 Reserve the first 64K of physical RAM on BIOSes that are known
1190 to potentially corrupt that memory range. A numbers of BIOSes are
1191 known to utilize this area during suspend/resume, so it must not
1192 be used by the kernel.
1194 Set this to N if you are absolutely sure that you trust the BIOS
1195 to get all its memory reservations and usages right.
1197 If you have doubts about the BIOS (e.g. suspend/resume does not
1198 work or there's kernel crashes after certain hardware hotplug
1199 events) and it's not AMI or Phoenix, then you might want to enable
1200 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1201 corruption patterns.
1203 Say Y if unsure.
1205 config MATH_EMULATION
1206 bool
1207 prompt "Math emulation" if X86_32
1208 ---help---
1209 Linux can emulate a math coprocessor (used for floating point
1210 operations) if you don't have one. 486DX and Pentium processors have
1211 a math coprocessor built in, 486SX and 386 do not, unless you added
1212 a 487DX or 387, respectively. (The messages during boot time can
1213 give you some hints here ["man dmesg"].) Everyone needs either a
1214 coprocessor or this emulation.
1216 If you don't have a math coprocessor, you need to say Y here; if you
1217 say Y here even though you have a coprocessor, the coprocessor will
1218 be used nevertheless. (This behavior can be changed with the kernel
1219 command line option "no387", which comes handy if your coprocessor
1220 is broken. Try "man bootparam" or see the documentation of your boot
1221 loader (lilo or loadlin) about how to pass options to the kernel at
1222 boot time.) This means that it is a good idea to say Y here if you
1223 intend to use this kernel on different machines.
1225 More information about the internals of the Linux math coprocessor
1226 emulation can be found in <file:arch/x86/math-emu/README>.
1228 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1229 kernel, it won't hurt.
1231 config MTRR
1232 bool "MTRR (Memory Type Range Register) support"
1233 ---help---
1234 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1235 the Memory Type Range Registers (MTRRs) may be used to control
1236 processor access to memory ranges. This is most useful if you have
1237 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1238 allows bus write transfers to be combined into a larger transfer
1239 before bursting over the PCI/AGP bus. This can increase performance
1240 of image write operations 2.5 times or more. Saying Y here creates a
1241 /proc/mtrr file which may be used to manipulate your processor's
1242 MTRRs. Typically the X server should use this.
1244 This code has a reasonably generic interface so that similar
1245 control registers on other processors can be easily supported
1246 as well:
1248 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1249 Registers (ARRs) which provide a similar functionality to MTRRs. For
1250 these, the ARRs are used to emulate the MTRRs.
1251 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1252 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1253 write-combining. All of these processors are supported by this code
1254 and it makes sense to say Y here if you have one of them.
1256 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1257 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1258 can lead to all sorts of problems, so it's good to say Y here.
1260 You can safely say Y even if your machine doesn't have MTRRs, you'll
1261 just add about 9 KB to your kernel.
1263 See <file:Documentation/x86/mtrr.txt> for more information.
1265 config MTRR_SANITIZER
1266 def_bool y
1267 prompt "MTRR cleanup support"
1268 depends on MTRR
1269 ---help---
1270 Convert MTRR layout from continuous to discrete, so X drivers can
1271 add writeback entries.
1273 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1274 The largest mtrr entry size for a continous block can be set with
1275 mtrr_chunk_size.
1277 If unsure, say Y.
1279 config MTRR_SANITIZER_ENABLE_DEFAULT
1280 int "MTRR cleanup enable value (0-1)"
1281 range 0 1
1282 default "0"
1283 depends on MTRR_SANITIZER
1284 ---help---
1285 Enable mtrr cleanup default value
1287 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1288 int "MTRR cleanup spare reg num (0-7)"
1289 range 0 7
1290 default "1"
1291 depends on MTRR_SANITIZER
1292 ---help---
1293 mtrr cleanup spare entries default, it can be changed via
1294 mtrr_spare_reg_nr=N on the kernel command line.
1296 config X86_PAT
1297 bool
1298 prompt "x86 PAT support"
1299 depends on MTRR
1300 ---help---
1301 Use PAT attributes to setup page level cache control.
1303 PATs are the modern equivalents of MTRRs and are much more
1304 flexible than MTRRs.
1306 Say N here if you see bootup problems (boot crash, boot hang,
1307 spontaneous reboots) or a non-working video driver.
1309 If unsure, say Y.
1311 config EFI
1312 bool "EFI runtime service support"
1313 depends on ACPI
1314 ---help---
1315 This enables the kernel to use EFI runtime services that are
1316 available (such as the EFI variable services).
1318 This option is only useful on systems that have EFI firmware.
1319 In addition, you should use the latest ELILO loader available
1320 at <http://elilo.sourceforge.net> in order to take advantage
1321 of EFI runtime services. However, even with this option, the
1322 resultant kernel should continue to boot on existing non-EFI
1323 platforms.
1325 config SECCOMP
1326 def_bool y
1327 prompt "Enable seccomp to safely compute untrusted bytecode"
1328 ---help---
1329 This kernel feature is useful for number crunching applications
1330 that may need to compute untrusted bytecode during their
1331 execution. By using pipes or other transports made available to
1332 the process as file descriptors supporting the read/write
1333 syscalls, it's possible to isolate those applications in
1334 their own address space using seccomp. Once seccomp is
1335 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1336 and the task is only allowed to execute a few safe syscalls
1337 defined by each seccomp mode.
1339 If unsure, say Y. Only embedded should say N here.
1341 config CC_STACKPROTECTOR_ALL
1342 bool
1344 config CC_STACKPROTECTOR
1345 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1346 select CC_STACKPROTECTOR_ALL
1347 ---help---
1348 This option turns on the -fstack-protector GCC feature. This
1349 feature puts, at the beginning of functions, a canary value on
1350 the stack just before the return address, and validates
1351 the value just before actually returning. Stack based buffer
1352 overflows (that need to overwrite this return address) now also
1353 overwrite the canary, which gets detected and the attack is then
1354 neutralized via a kernel panic.
1356 This feature requires gcc version 4.2 or above, or a distribution
1357 gcc with the feature backported. Older versions are automatically
1358 detected and for those versions, this configuration option is
1359 ignored. (and a warning is printed during bootup)
1361 source kernel/Kconfig.hz
1363 config KEXEC
1364 bool "kexec system call"
1365 ---help---
1366 kexec is a system call that implements the ability to shutdown your
1367 current kernel, and to start another kernel. It is like a reboot
1368 but it is independent of the system firmware. And like a reboot
1369 you can start any kernel with it, not just Linux.
1371 The name comes from the similarity to the exec system call.
1373 It is an ongoing process to be certain the hardware in a machine
1374 is properly shutdown, so do not be surprised if this code does not
1375 initially work for you. It may help to enable device hotplugging
1376 support. As of this writing the exact hardware interface is
1377 strongly in flux, so no good recommendation can be made.
1379 config CRASH_DUMP
1380 bool "kernel crash dumps"
1381 depends on X86_64 || (X86_32 && HIGHMEM)
1382 ---help---
1383 Generate crash dump after being started by kexec.
1384 This should be normally only set in special crash dump kernels
1385 which are loaded in the main kernel with kexec-tools into
1386 a specially reserved region and then later executed after
1387 a crash by kdump/kexec. The crash dump kernel must be compiled
1388 to a memory address not used by the main kernel or BIOS using
1389 PHYSICAL_START, or it must be built as a relocatable image
1390 (CONFIG_RELOCATABLE=y).
1391 For more details see Documentation/kdump/kdump.txt
1393 config KEXEC_JUMP
1394 bool "kexec jump (EXPERIMENTAL)"
1395 depends on EXPERIMENTAL
1396 depends on KEXEC && HIBERNATION && X86_32
1397 ---help---
1398 Jump between original kernel and kexeced kernel and invoke
1399 code in physical address mode via KEXEC
1401 config PHYSICAL_START
1402 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1403 default "0x1000000" if X86_NUMAQ
1404 default "0x200000" if X86_64
1405 default "0x100000"
1406 ---help---
1407 This gives the physical address where the kernel is loaded.
1409 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1410 bzImage will decompress itself to above physical address and
1411 run from there. Otherwise, bzImage will run from the address where
1412 it has been loaded by the boot loader and will ignore above physical
1413 address.
1415 In normal kdump cases one does not have to set/change this option
1416 as now bzImage can be compiled as a completely relocatable image
1417 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1418 address. This option is mainly useful for the folks who don't want
1419 to use a bzImage for capturing the crash dump and want to use a
1420 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1421 to be specifically compiled to run from a specific memory area
1422 (normally a reserved region) and this option comes handy.
1424 So if you are using bzImage for capturing the crash dump, leave
1425 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1426 Otherwise if you plan to use vmlinux for capturing the crash dump
1427 change this value to start of the reserved region (Typically 16MB
1428 0x1000000). In other words, it can be set based on the "X" value as
1429 specified in the "crashkernel=YM@XM" command line boot parameter
1430 passed to the panic-ed kernel. Typically this parameter is set as
1431 crashkernel=64M@16M. Please take a look at
1432 Documentation/kdump/kdump.txt for more details about crash dumps.
1434 Usage of bzImage for capturing the crash dump is recommended as
1435 one does not have to build two kernels. Same kernel can be used
1436 as production kernel and capture kernel. Above option should have
1437 gone away after relocatable bzImage support is introduced. But it
1438 is present because there are users out there who continue to use
1439 vmlinux for dump capture. This option should go away down the
1440 line.
1442 Don't change this unless you know what you are doing.
1444 config RELOCATABLE
1445 bool "Build a relocatable kernel (EXPERIMENTAL)"
1446 depends on EXPERIMENTAL
1447 ---help---
1448 This builds a kernel image that retains relocation information
1449 so it can be loaded someplace besides the default 1MB.
1450 The relocations tend to make the kernel binary about 10% larger,
1451 but are discarded at runtime.
1453 One use is for the kexec on panic case where the recovery kernel
1454 must live at a different physical address than the primary
1455 kernel.
1457 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1458 it has been loaded at and the compile time physical address
1459 (CONFIG_PHYSICAL_START) is ignored.
1461 config PHYSICAL_ALIGN
1462 hex
1463 prompt "Alignment value to which kernel should be aligned" if X86_32
1464 default "0x100000" if X86_32
1465 default "0x200000" if X86_64
1466 range 0x2000 0x400000
1467 ---help---
1468 This value puts the alignment restrictions on physical address
1469 where kernel is loaded and run from. Kernel is compiled for an
1470 address which meets above alignment restriction.
1472 If bootloader loads the kernel at a non-aligned address and
1473 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1474 address aligned to above value and run from there.
1476 If bootloader loads the kernel at a non-aligned address and
1477 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1478 load address and decompress itself to the address it has been
1479 compiled for and run from there. The address for which kernel is
1480 compiled already meets above alignment restrictions. Hence the
1481 end result is that kernel runs from a physical address meeting
1482 above alignment restrictions.
1484 Don't change this unless you know what you are doing.
1486 config HOTPLUG_CPU
1487 bool "Support for hot-pluggable CPUs"
1488 depends on SMP && HOTPLUG
1489 ---help---
1490 Say Y here to allow turning CPUs off and on. CPUs can be
1491 controlled through /sys/devices/system/cpu.
1492 ( Note: power management support will enable this option
1493 automatically on SMP systems. )
1494 Say N if you want to disable CPU hotplug.
1496 config COMPAT_VDSO
1497 def_bool y
1498 prompt "Compat VDSO support"
1499 depends on X86_32 || IA32_EMULATION
1500 ---help---
1501 Map the 32-bit VDSO to the predictable old-style address too.
1502 ---help---
1503 Say N here if you are running a sufficiently recent glibc
1504 version (2.3.3 or later), to remove the high-mapped
1505 VDSO mapping and to exclusively use the randomized VDSO.
1507 If unsure, say Y.
1509 config CMDLINE_BOOL
1510 bool "Built-in kernel command line"
1511 default n
1512 ---help---
1513 Allow for specifying boot arguments to the kernel at
1514 build time. On some systems (e.g. embedded ones), it is
1515 necessary or convenient to provide some or all of the
1516 kernel boot arguments with the kernel itself (that is,
1517 to not rely on the boot loader to provide them.)
1519 To compile command line arguments into the kernel,
1520 set this option to 'Y', then fill in the
1521 the boot arguments in CONFIG_CMDLINE.
1523 Systems with fully functional boot loaders (i.e. non-embedded)
1524 should leave this option set to 'N'.
1526 config CMDLINE
1527 string "Built-in kernel command string"
1528 depends on CMDLINE_BOOL
1529 default ""
1530 ---help---
1531 Enter arguments here that should be compiled into the kernel
1532 image and used at boot time. If the boot loader provides a
1533 command line at boot time, it is appended to this string to
1534 form the full kernel command line, when the system boots.
1536 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1537 change this behavior.
1539 In most cases, the command line (whether built-in or provided
1540 by the boot loader) should specify the device for the root
1541 file system.
1543 config CMDLINE_OVERRIDE
1544 bool "Built-in command line overrides boot loader arguments"
1545 default n
1546 depends on CMDLINE_BOOL
1547 ---help---
1548 Set this option to 'Y' to have the kernel ignore the boot loader
1549 command line, and use ONLY the built-in command line.
1551 This is used to work around broken boot loaders. This should
1552 be set to 'N' under normal conditions.
1554 endmenu
1556 config ARCH_ENABLE_MEMORY_HOTPLUG
1557 def_bool y
1558 depends on X86_64 || (X86_32 && HIGHMEM)
1560 config ARCH_ENABLE_MEMORY_HOTREMOVE
1561 def_bool y
1562 depends on MEMORY_HOTPLUG
1564 config HAVE_ARCH_EARLY_PFN_TO_NID
1565 def_bool X86_64
1566 depends on NUMA
1568 menu "Power management and ACPI options"
1570 config ARCH_HIBERNATION_HEADER
1571 def_bool y
1572 depends on X86_64 && HIBERNATION
1574 source "kernel/power/Kconfig"
1576 source "drivers/acpi/Kconfig"
1578 config X86_APM_BOOT
1579 bool
1580 default y
1581 depends on APM || APM_MODULE
1583 menuconfig APM
1584 tristate "APM (Advanced Power Management) BIOS support"
1585 depends on X86_32 && PM_SLEEP
1586 ---help---
1587 APM is a BIOS specification for saving power using several different
1588 techniques. This is mostly useful for battery powered laptops with
1589 APM compliant BIOSes. If you say Y here, the system time will be
1590 reset after a RESUME operation, the /proc/apm device will provide
1591 battery status information, and user-space programs will receive
1592 notification of APM "events" (e.g. battery status change).
1594 If you select "Y" here, you can disable actual use of the APM
1595 BIOS by passing the "apm=off" option to the kernel at boot time.
1597 Note that the APM support is almost completely disabled for
1598 machines with more than one CPU.
1600 In order to use APM, you will need supporting software. For location
1601 and more information, read <file:Documentation/power/pm.txt> and the
1602 Battery Powered Linux mini-HOWTO, available from
1603 <http://www.tldp.org/docs.html#howto>.
1605 This driver does not spin down disk drives (see the hdparm(8)
1606 manpage ("man 8 hdparm") for that), and it doesn't turn off
1607 VESA-compliant "green" monitors.
1609 This driver does not support the TI 4000M TravelMate and the ACER
1610 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1611 desktop machines also don't have compliant BIOSes, and this driver
1612 may cause those machines to panic during the boot phase.
1614 Generally, if you don't have a battery in your machine, there isn't
1615 much point in using this driver and you should say N. If you get
1616 random kernel OOPSes or reboots that don't seem to be related to
1617 anything, try disabling/enabling this option (or disabling/enabling
1618 APM in your BIOS).
1620 Some other things you should try when experiencing seemingly random,
1621 "weird" problems:
1623 1) make sure that you have enough swap space and that it is
1624 enabled.
1625 2) pass the "no-hlt" option to the kernel
1626 3) switch on floating point emulation in the kernel and pass
1627 the "no387" option to the kernel
1628 4) pass the "floppy=nodma" option to the kernel
1629 5) pass the "mem=4M" option to the kernel (thereby disabling
1630 all but the first 4 MB of RAM)
1631 6) make sure that the CPU is not over clocked.
1632 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1633 8) disable the cache from your BIOS settings
1634 9) install a fan for the video card or exchange video RAM
1635 10) install a better fan for the CPU
1636 11) exchange RAM chips
1637 12) exchange the motherboard.
1639 To compile this driver as a module, choose M here: the
1640 module will be called apm.
1642 if APM
1644 config APM_IGNORE_USER_SUSPEND
1645 bool "Ignore USER SUSPEND"
1646 ---help---
1647 This option will ignore USER SUSPEND requests. On machines with a
1648 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1649 series notebooks, it is necessary to say Y because of a BIOS bug.
1651 config APM_DO_ENABLE
1652 bool "Enable PM at boot time"
1653 ---help---
1654 Enable APM features at boot time. From page 36 of the APM BIOS
1655 specification: "When disabled, the APM BIOS does not automatically
1656 power manage devices, enter the Standby State, enter the Suspend
1657 State, or take power saving steps in response to CPU Idle calls."
1658 This driver will make CPU Idle calls when Linux is idle (unless this
1659 feature is turned off -- see "Do CPU IDLE calls", below). This
1660 should always save battery power, but more complicated APM features
1661 will be dependent on your BIOS implementation. You may need to turn
1662 this option off if your computer hangs at boot time when using APM
1663 support, or if it beeps continuously instead of suspending. Turn
1664 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1665 T400CDT. This is off by default since most machines do fine without
1666 this feature.
1668 config APM_CPU_IDLE
1669 bool "Make CPU Idle calls when idle"
1670 ---help---
1671 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1672 On some machines, this can activate improved power savings, such as
1673 a slowed CPU clock rate, when the machine is idle. These idle calls
1674 are made after the idle loop has run for some length of time (e.g.,
1675 333 mS). On some machines, this will cause a hang at boot time or
1676 whenever the CPU becomes idle. (On machines with more than one CPU,
1677 this option does nothing.)
1679 config APM_DISPLAY_BLANK
1680 bool "Enable console blanking using APM"
1681 ---help---
1682 Enable console blanking using the APM. Some laptops can use this to
1683 turn off the LCD backlight when the screen blanker of the Linux
1684 virtual console blanks the screen. Note that this is only used by
1685 the virtual console screen blanker, and won't turn off the backlight
1686 when using the X Window system. This also doesn't have anything to
1687 do with your VESA-compliant power-saving monitor. Further, this
1688 option doesn't work for all laptops -- it might not turn off your
1689 backlight at all, or it might print a lot of errors to the console,
1690 especially if you are using gpm.
1692 config APM_ALLOW_INTS
1693 bool "Allow interrupts during APM BIOS calls"
1694 ---help---
1695 Normally we disable external interrupts while we are making calls to
1696 the APM BIOS as a measure to lessen the effects of a badly behaving
1697 BIOS implementation. The BIOS should reenable interrupts if it
1698 needs to. Unfortunately, some BIOSes do not -- especially those in
1699 many of the newer IBM Thinkpads. If you experience hangs when you
1700 suspend, try setting this to Y. Otherwise, say N.
1702 endif # APM
1704 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1706 source "drivers/cpuidle/Kconfig"
1708 source "drivers/idle/Kconfig"
1710 endmenu
1713 menu "Bus options (PCI etc.)"
1715 config PCI
1716 bool "PCI support"
1717 default y
1718 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1719 ---help---
1720 Find out whether you have a PCI motherboard. PCI is the name of a
1721 bus system, i.e. the way the CPU talks to the other stuff inside
1722 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1723 VESA. If you have PCI, say Y, otherwise N.
1725 choice
1726 prompt "PCI access mode"
1727 depends on X86_32 && PCI
1728 default PCI_GOANY
1729 ---help---
1730 On PCI systems, the BIOS can be used to detect the PCI devices and
1731 determine their configuration. However, some old PCI motherboards
1732 have BIOS bugs and may crash if this is done. Also, some embedded
1733 PCI-based systems don't have any BIOS at all. Linux can also try to
1734 detect the PCI hardware directly without using the BIOS.
1736 With this option, you can specify how Linux should detect the
1737 PCI devices. If you choose "BIOS", the BIOS will be used,
1738 if you choose "Direct", the BIOS won't be used, and if you
1739 choose "MMConfig", then PCI Express MMCONFIG will be used.
1740 If you choose "Any", the kernel will try MMCONFIG, then the
1741 direct access method and falls back to the BIOS if that doesn't
1742 work. If unsure, go with the default, which is "Any".
1744 config PCI_GOBIOS
1745 bool "BIOS"
1747 config PCI_GOMMCONFIG
1748 bool "MMConfig"
1750 config PCI_GODIRECT
1751 bool "Direct"
1753 config PCI_GOOLPC
1754 bool "OLPC"
1755 depends on OLPC
1757 config PCI_GOANY
1758 bool "Any"
1760 endchoice
1762 config PCI_BIOS
1763 def_bool y
1764 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1766 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1767 config PCI_DIRECT
1768 def_bool y
1769 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1771 config PCI_MMCONFIG
1772 def_bool y
1773 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1775 config PCI_OLPC
1776 def_bool y
1777 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1779 config PCI_DOMAINS
1780 def_bool y
1781 depends on PCI
1783 config PCI_MMCONFIG
1784 bool "Support mmconfig PCI config space access"
1785 depends on X86_64 && PCI && ACPI
1787 config DMAR
1788 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1789 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1790 ---help---
1791 DMA remapping (DMAR) devices support enables independent address
1792 translations for Direct Memory Access (DMA) from devices.
1793 These DMA remapping devices are reported via ACPI tables
1794 and include PCI device scope covered by these DMA
1795 remapping devices.
1797 config DMAR_DEFAULT_ON
1798 def_bool n
1799 prompt "Enable DMA Remapping Devices by default"
1800 depends on DMAR
1801 help
1802 Selecting this option will enable a DMAR device at boot time if
1803 one is found. If this option is not selected, DMAR support can
1804 be enabled by passing intel_iommu=on to the kernel. It is
1805 recommended you say N here while the DMAR code remains
1806 experimental.
1808 config DMAR_GFX_WA
1809 def_bool y
1810 prompt "Support for Graphics workaround"
1811 depends on DMAR
1812 ---help---
1813 Current Graphics drivers tend to use physical address
1814 for DMA and avoid using DMA APIs. Setting this config
1815 option permits the IOMMU driver to set a unity map for
1816 all the OS-visible memory. Hence the driver can continue
1817 to use physical addresses for DMA.
1819 config DMAR_FLOPPY_WA
1820 def_bool y
1821 depends on DMAR
1822 ---help---
1823 Floppy disk drivers are know to bypass DMA API calls
1824 thereby failing to work when IOMMU is enabled. This
1825 workaround will setup a 1:1 mapping for the first
1826 16M to make floppy (an ISA device) work.
1828 config INTR_REMAP
1829 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1830 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1831 ---help---
1832 Supports Interrupt remapping for IO-APIC and MSI devices.
1833 To use x2apic mode in the CPU's which support x2APIC enhancements or
1834 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1836 source "drivers/pci/pcie/Kconfig"
1838 source "drivers/pci/Kconfig"
1840 # x86_64 have no ISA slots, but do have ISA-style DMA.
1841 config ISA_DMA_API
1842 def_bool y
1844 if X86_32
1846 config ISA
1847 bool "ISA support"
1848 ---help---
1849 Find out whether you have ISA slots on your motherboard. ISA is the
1850 name of a bus system, i.e. the way the CPU talks to the other stuff
1851 inside your box. Other bus systems are PCI, EISA, MicroChannel
1852 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1853 newer boards don't support it. If you have ISA, say Y, otherwise N.
1855 config EISA
1856 bool "EISA support"
1857 depends on ISA
1858 ---help---
1859 The Extended Industry Standard Architecture (EISA) bus was
1860 developed as an open alternative to the IBM MicroChannel bus.
1862 The EISA bus provided some of the features of the IBM MicroChannel
1863 bus while maintaining backward compatibility with cards made for
1864 the older ISA bus. The EISA bus saw limited use between 1988 and
1865 1995 when it was made obsolete by the PCI bus.
1867 Say Y here if you are building a kernel for an EISA-based machine.
1869 Otherwise, say N.
1871 source "drivers/eisa/Kconfig"
1873 config MCA
1874 bool "MCA support"
1875 ---help---
1876 MicroChannel Architecture is found in some IBM PS/2 machines and
1877 laptops. It is a bus system similar to PCI or ISA. See
1878 <file:Documentation/mca.txt> (and especially the web page given
1879 there) before attempting to build an MCA bus kernel.
1881 source "drivers/mca/Kconfig"
1883 config SCx200
1884 tristate "NatSemi SCx200 support"
1885 ---help---
1886 This provides basic support for National Semiconductor's
1887 (now AMD's) Geode processors. The driver probes for the
1888 PCI-IDs of several on-chip devices, so its a good dependency
1889 for other scx200_* drivers.
1891 If compiled as a module, the driver is named scx200.
1893 config SCx200HR_TIMER
1894 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1895 depends on SCx200 && GENERIC_TIME
1896 default y
1897 ---help---
1898 This driver provides a clocksource built upon the on-chip
1899 27MHz high-resolution timer. Its also a workaround for
1900 NSC Geode SC-1100's buggy TSC, which loses time when the
1901 processor goes idle (as is done by the scheduler). The
1902 other workaround is idle=poll boot option.
1904 config GEODE_MFGPT_TIMER
1905 def_bool y
1906 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1907 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1908 ---help---
1909 This driver provides a clock event source based on the MFGPT
1910 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1911 MFGPTs have a better resolution and max interval than the
1912 generic PIT, and are suitable for use as high-res timers.
1914 config OLPC
1915 bool "One Laptop Per Child support"
1916 default n
1917 ---help---
1918 Add support for detecting the unique features of the OLPC
1919 XO hardware.
1921 endif # X86_32
1923 config K8_NB
1924 def_bool y
1925 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1927 source "drivers/pcmcia/Kconfig"
1929 source "drivers/pci/hotplug/Kconfig"
1931 endmenu
1934 menu "Executable file formats / Emulations"
1936 source "fs/Kconfig.binfmt"
1938 config IA32_EMULATION
1939 bool "IA32 Emulation"
1940 depends on X86_64
1941 select COMPAT_BINFMT_ELF
1942 ---help---
1943 Include code to run 32-bit programs under a 64-bit kernel. You should
1944 likely turn this on, unless you're 100% sure that you don't have any
1945 32-bit programs left.
1947 config IA32_AOUT
1948 tristate "IA32 a.out support"
1949 depends on IA32_EMULATION
1950 ---help---
1951 Support old a.out binaries in the 32bit emulation.
1953 config COMPAT
1954 def_bool y
1955 depends on IA32_EMULATION
1957 config COMPAT_FOR_U64_ALIGNMENT
1958 def_bool COMPAT
1959 depends on X86_64
1961 config SYSVIPC_COMPAT
1962 def_bool y
1963 depends on COMPAT && SYSVIPC
1965 endmenu
1968 config HAVE_ATOMIC_IOMAP
1969 def_bool y
1970 depends on X86_32
1972 source "net/Kconfig"
1974 source "drivers/Kconfig"
1976 source "drivers/firmware/Kconfig"
1978 source "fs/Kconfig"
1980 source "arch/x86/Kconfig.debug"
1982 source "security/Kconfig"
1984 source "crypto/Kconfig"
1986 source "arch/x86/kvm/Kconfig"
1988 source "lib/Kconfig"