| blob | a2337683856afd14060fd6df4dab2c90ffb2bdeb |
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 if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
38 select HAVE_ARCH_KGDB if !X86_VOYAGER
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
43 select HAVE_KERNEL_GZIP
44 select HAVE_KERNEL_BZIP2
45 select HAVE_KERNEL_LZMA
47 config ARCH_DEFCONFIG
48 string
49 default "arch/x86/configs/i386_defconfig" if X86_32
50 default "arch/x86/configs/x86_64_defconfig" if X86_64
52 config GENERIC_TIME
53 def_bool y
55 config GENERIC_CMOS_UPDATE
56 def_bool y
58 config CLOCKSOURCE_WATCHDOG
59 def_bool y
61 config GENERIC_CLOCKEVENTS
62 def_bool y
64 config GENERIC_CLOCKEVENTS_BROADCAST
65 def_bool y
66 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
68 config LOCKDEP_SUPPORT
69 def_bool y
71 config STACKTRACE_SUPPORT
72 def_bool y
74 config HAVE_LATENCYTOP_SUPPORT
75 def_bool y
77 config FAST_CMPXCHG_LOCAL
78 bool
79 default y
81 config MMU
82 def_bool y
84 config ZONE_DMA
85 def_bool y
87 config SBUS
88 bool
90 config GENERIC_ISA_DMA
91 def_bool y
93 config GENERIC_IOMAP
94 def_bool y
96 config GENERIC_BUG
97 def_bool y
98 depends on BUG
99 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
101 config GENERIC_BUG_RELATIVE_POINTERS
102 bool
104 config GENERIC_HWEIGHT
105 def_bool y
107 config GENERIC_GPIO
108 bool
110 config ARCH_MAY_HAVE_PC_FDC
111 def_bool y
113 config RWSEM_GENERIC_SPINLOCK
114 def_bool !X86_XADD
116 config RWSEM_XCHGADD_ALGORITHM
117 def_bool X86_XADD
119 config ARCH_HAS_CPU_IDLE_WAIT
120 def_bool y
122 config GENERIC_CALIBRATE_DELAY
123 def_bool y
125 config GENERIC_TIME_VSYSCALL
126 bool
127 default X86_64
129 config ARCH_HAS_CPU_RELAX
130 def_bool y
132 config ARCH_HAS_DEFAULT_IDLE
133 def_bool y
135 config ARCH_HAS_CACHE_LINE_SIZE
136 def_bool y
138 config HAVE_SETUP_PER_CPU_AREA
139 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
141 config HAVE_CPUMASK_OF_CPU_MAP
142 def_bool X86_64_SMP
144 config ARCH_HIBERNATION_POSSIBLE
145 def_bool y
146 depends on !SMP || !X86_VOYAGER
148 config ARCH_SUSPEND_POSSIBLE
149 def_bool y
150 depends on !X86_VOYAGER
152 config ZONE_DMA32
153 bool
154 default X86_64
156 config ARCH_POPULATES_NODE_MAP
157 def_bool y
159 config AUDIT_ARCH
160 bool
161 default X86_64
163 config ARCH_SUPPORTS_OPTIMIZED_INLINING
164 def_bool y
166 # Use the generic interrupt handling code in kernel/irq/:
167 config GENERIC_HARDIRQS
168 bool
169 default y
171 config GENERIC_IRQ_PROBE
172 bool
173 default y
175 config GENERIC_PENDING_IRQ
176 bool
177 depends on GENERIC_HARDIRQS && SMP
178 default y
180 config X86_SMP
181 bool
182 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
183 default y
185 config USE_GENERIC_SMP_HELPERS
186 def_bool y
187 depends on SMP
189 config X86_32_SMP
190 def_bool y
191 depends on X86_32 && SMP
193 config X86_64_SMP
194 def_bool y
195 depends on X86_64 && SMP
197 config X86_HT
198 bool
199 depends on SMP
200 depends on (X86_32 && !X86_VOYAGER) || X86_64
201 default y
203 config X86_BIOS_REBOOT
204 bool
205 depends on !X86_VOYAGER
206 default y
208 config X86_TRAMPOLINE
209 bool
210 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
211 default y
213 config KTIME_SCALAR
214 def_bool X86_32
215 source "init/Kconfig"
216 source "kernel/Kconfig.freezer"
218 menu "Processor type and features"
220 source "kernel/time/Kconfig"
222 config SMP
223 bool "Symmetric multi-processing support"
224 ---help---
225 This enables support for systems with more than one CPU. If you have
226 a system with only one CPU, like most personal computers, say N. If
227 you have a system with more than one CPU, say Y.
229 If you say N here, the kernel will run on single and multiprocessor
230 machines, but will use only one CPU of a multiprocessor machine. If
231 you say Y here, the kernel will run on many, but not all,
232 singleprocessor machines. On a singleprocessor machine, the kernel
233 will run faster if you say N here.
235 Note that if you say Y here and choose architecture "586" or
236 "Pentium" under "Processor family", the kernel will not work on 486
237 architectures. Similarly, multiprocessor kernels for the "PPro"
238 architecture may not work on all Pentium based boards.
240 People using multiprocessor machines who say Y here should also say
241 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
242 Management" code will be disabled if you say Y here.
244 See also <file:Documentation/i386/IO-APIC.txt>,
245 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
246 <http://www.tldp.org/docs.html#howto>.
248 If you don't know what to do here, say N.
250 config X86_HAS_BOOT_CPU_ID
251 def_bool y
252 depends on X86_VOYAGER
254 config SPARSE_IRQ
255 bool "Support sparse irq numbering"
256 depends on PCI_MSI || HT_IRQ
257 help
258 This enables support for sparse irqs. This is useful for distro
259 kernels that want to define a high CONFIG_NR_CPUS value but still
260 want to have low kernel memory footprint on smaller machines.
262 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
263 out the irq_desc[] array in a more NUMA-friendly way. )
265 If you don't know what to do here, say N.
267 config NUMA_MIGRATE_IRQ_DESC
268 bool "Move irq desc when changing irq smp_affinity"
269 depends on SPARSE_IRQ && NUMA
270 default n
271 help
272 This enables moving irq_desc to cpu/node that irq will use handled.
274 If you don't know what to do here, say N.
276 config X86_FIND_SMP_CONFIG
277 def_bool y
278 depends on X86_MPPARSE || X86_VOYAGER
280 config X86_MPPARSE
281 bool "Enable MPS table" if ACPI
282 default y
283 depends on X86_LOCAL_APIC
284 help
285 For old smp systems that do not have proper acpi support. Newer systems
286 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
288 choice
289 prompt "Subarchitecture Type"
290 default X86_PC
292 config X86_PC
293 bool "PC-compatible"
294 help
295 Choose this option if your computer is a standard PC or compatible.
297 config X86_ELAN
298 bool "AMD Elan"
299 depends on X86_32
300 help
301 Select this for an AMD Elan processor.
303 Do not use this option for K6/Athlon/Opteron processors!
305 If unsure, choose "PC-compatible" instead.
307 config X86_VOYAGER
308 bool "Voyager (NCR)"
309 depends on X86_32 && (SMP || BROKEN) && !PCI
310 help
311 Voyager is an MCA-based 32-way capable SMP architecture proprietary
312 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
314 *** WARNING ***
316 If you do not specifically know you have a Voyager based machine,
317 say N here, otherwise the kernel you build will not be bootable.
319 config X86_GENERICARCH
320 bool "Generic architecture"
321 depends on X86_32
322 help
323 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
324 subarchitectures. It is intended for a generic binary kernel.
325 if you select them all, kernel will probe it one by one. and will
326 fallback to default.
328 if X86_GENERICARCH
330 config X86_NUMAQ
331 bool "NUMAQ (IBM/Sequent)"
332 depends on SMP && X86_32 && PCI && X86_MPPARSE
333 select NUMA
334 help
335 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
336 NUMA multiquad box. This changes the way that processors are
337 bootstrapped, and uses Clustered Logical APIC addressing mode instead
338 of Flat Logical. You will need a new lynxer.elf file to flash your
339 firmware with - send email to <Martin.Bligh@us.ibm.com>.
341 config X86_SUMMIT
342 bool "Summit/EXA (IBM x440)"
343 depends on X86_32 && SMP
344 help
345 This option is needed for IBM systems that use the Summit/EXA chipset.
346 In particular, it is needed for the x440.
348 config X86_ES7000
349 bool "Support for Unisys ES7000 IA32 series"
350 depends on X86_32 && SMP
351 help
352 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
353 supposed to run on an IA32-based Unisys ES7000 system.
355 config X86_BIGSMP
356 bool "Support for big SMP systems with more than 8 CPUs"
357 depends on X86_32 && SMP
358 help
359 This option is needed for the systems that have more than 8 CPUs
360 and if the system is not of any sub-arch type above.
362 endif
364 config X86_VSMP
365 bool "Support for ScaleMP vSMP"
366 select PARAVIRT
367 depends on X86_64 && PCI
368 help
369 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
370 supposed to run on these EM64T-based machines. Only choose this option
371 if you have one of these machines.
373 endchoice
375 config X86_VISWS
376 bool "SGI 320/540 (Visual Workstation)"
377 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
378 help
379 The SGI Visual Workstation series is an IA32-based workstation
380 based on SGI systems chips with some legacy PC hardware attached.
382 Say Y here to create a kernel to run on the SGI 320 or 540.
384 A kernel compiled for the Visual Workstation will run on general
385 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
387 config X86_RDC321X
388 bool "RDC R-321x SoC"
389 depends on X86_32
390 select M486
391 select X86_REBOOTFIXUPS
392 help
393 This option is needed for RDC R-321x system-on-chip, also known
394 as R-8610-(G).
395 If you don't have one of these chips, you should say N here.
397 config SCHED_OMIT_FRAME_POINTER
398 def_bool y
399 prompt "Single-depth WCHAN output"
400 depends on X86
401 help
402 Calculate simpler /proc/<PID>/wchan values. If this option
403 is disabled then wchan values will recurse back to the
404 caller function. This provides more accurate wchan values,
405 at the expense of slightly more scheduling overhead.
407 If in doubt, say "Y".
409 menuconfig PARAVIRT_GUEST
410 bool "Paravirtualized guest support"
411 help
412 Say Y here to get to see options related to running Linux under
413 various hypervisors. This option alone does not add any kernel code.
415 If you say N, all options in this submenu will be skipped and disabled.
417 if PARAVIRT_GUEST
419 source "arch/x86/xen/Kconfig"
421 config VMI
422 bool "VMI Guest support"
423 select PARAVIRT
424 depends on X86_32
425 depends on !X86_VOYAGER
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 depends on !X86_VOYAGER
437 help
438 Turning on this option will allow you to run a paravirtualized clock
439 when running over the KVM hypervisor. Instead of relying on a PIT
440 (or probably other) emulation by the underlying device model, the host
441 provides the guest with timing infrastructure such as time of day, and
442 system time
444 config KVM_GUEST
445 bool "KVM Guest support"
446 select PARAVIRT
447 depends on !X86_VOYAGER
448 help
449 This option enables various optimizations for running under the KVM
450 hypervisor.
452 source "arch/x86/lguest/Kconfig"
454 config PARAVIRT
455 bool "Enable paravirtualization code"
456 depends on !X86_VOYAGER
457 help
458 This changes the kernel so it can modify itself when it is run
459 under a hypervisor, potentially improving performance significantly
460 over full virtualization. However, when run without a hypervisor
461 the kernel is theoretically slower and slightly larger.
463 config PARAVIRT_CLOCK
464 bool
465 default n
467 endif
469 config PARAVIRT_DEBUG
470 bool "paravirt-ops debugging"
471 depends on PARAVIRT && DEBUG_KERNEL
472 help
473 Enable to debug paravirt_ops internals. Specifically, BUG if
474 a paravirt_op is missing when it is called.
476 config MEMTEST
477 bool "Memtest"
478 help
479 This option adds a kernel parameter 'memtest', which allows memtest
480 to be set.
481 memtest=0, mean disabled; -- default
482 memtest=1, mean do 1 test pattern;
483 ...
484 memtest=4, mean do 4 test patterns.
485 If you are unsure how to answer this question, answer N.
487 config X86_SUMMIT_NUMA
488 def_bool y
489 depends on X86_32 && NUMA && X86_GENERICARCH
491 config X86_CYCLONE_TIMER
492 def_bool y
493 depends on X86_GENERICARCH
495 source "arch/x86/Kconfig.cpu"
497 config HPET_TIMER
498 def_bool X86_64
499 prompt "HPET Timer Support" if X86_32
500 help
501 Use the IA-PC HPET (High Precision Event Timer) to manage
502 time in preference to the PIT and RTC, if a HPET is
503 present.
504 HPET is the next generation timer replacing legacy 8254s.
505 The HPET provides a stable time base on SMP
506 systems, unlike the TSC, but it is more expensive to access,
507 as it is off-chip. You can find the HPET spec at
508 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
510 You can safely choose Y here. However, HPET will only be
511 activated if the platform and the BIOS support this feature.
512 Otherwise the 8254 will be used for timing services.
514 Choose N to continue using the legacy 8254 timer.
516 config HPET_EMULATE_RTC
517 def_bool y
518 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
520 # Mark as embedded because too many people got it wrong.
521 # The code disables itself when not needed.
522 config DMI
523 default y
524 bool "Enable DMI scanning" if EMBEDDED
525 help
526 Enabled scanning of DMI to identify machine quirks. Say Y
527 here unless you have verified that your setup is not
528 affected by entries in the DMI blacklist. Required by PNP
529 BIOS code.
531 config GART_IOMMU
532 bool "GART IOMMU support" if EMBEDDED
533 default y
534 select SWIOTLB
535 select AGP
536 depends on X86_64 && PCI
537 help
538 Support for full DMA access of devices with 32bit memory access only
539 on systems with more than 3GB. This is usually needed for USB,
540 sound, many IDE/SATA chipsets and some other devices.
541 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
542 based hardware IOMMU and a software bounce buffer based IOMMU used
543 on Intel systems and as fallback.
544 The code is only active when needed (enough memory and limited
545 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
546 too.
548 config CALGARY_IOMMU
549 bool "IBM Calgary IOMMU support"
550 select SWIOTLB
551 depends on X86_64 && PCI && EXPERIMENTAL
552 help
553 Support for hardware IOMMUs in IBM's xSeries x366 and x460
554 systems. Needed to run systems with more than 3GB of memory
555 properly with 32-bit PCI devices that do not support DAC
556 (Double Address Cycle). Calgary also supports bus level
557 isolation, where all DMAs pass through the IOMMU. This
558 prevents them from going anywhere except their intended
559 destination. This catches hard-to-find kernel bugs and
560 mis-behaving drivers and devices that do not use the DMA-API
561 properly to set up their DMA buffers. The IOMMU can be
562 turned off at boot time with the iommu=off parameter.
563 Normally the kernel will make the right choice by itself.
564 If unsure, say Y.
566 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
567 def_bool y
568 prompt "Should Calgary be enabled by default?"
569 depends on CALGARY_IOMMU
570 help
571 Should Calgary be enabled by default? if you choose 'y', Calgary
572 will be used (if it exists). If you choose 'n', Calgary will not be
573 used even if it exists. If you choose 'n' and would like to use
574 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
575 If unsure, say Y.
577 config AMD_IOMMU
578 bool "AMD IOMMU support"
579 select SWIOTLB
580 select PCI_MSI
581 depends on X86_64 && PCI && ACPI
582 help
583 With this option you can enable support for AMD IOMMU hardware in
584 your system. An IOMMU is a hardware component which provides
585 remapping of DMA memory accesses from devices. With an AMD IOMMU you
586 can isolate the the DMA memory of different devices and protect the
587 system from misbehaving device drivers or hardware.
589 You can find out if your system has an AMD IOMMU if you look into
590 your BIOS for an option to enable it or if you have an IVRS ACPI
591 table.
593 config AMD_IOMMU_STATS
594 bool "Export AMD IOMMU statistics to debugfs"
595 depends on AMD_IOMMU
596 select DEBUG_FS
597 help
598 This option enables code in the AMD IOMMU driver to collect various
599 statistics about whats happening in the driver and exports that
600 information to userspace via debugfs.
601 If unsure, say N.
603 # need this always selected by IOMMU for the VIA workaround
604 config SWIOTLB
605 def_bool y if X86_64
606 help
607 Support for software bounce buffers used on x86-64 systems
608 which don't have a hardware IOMMU (e.g. the current generation
609 of Intel's x86-64 CPUs). Using this PCI devices which can only
610 access 32-bits of memory can be used on systems with more than
611 3 GB of memory. If unsure, say Y.
613 config IOMMU_HELPER
614 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
616 config IOMMU_API
617 def_bool (AMD_IOMMU || DMAR)
619 config MAXSMP
620 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
621 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
622 select CPUMASK_OFFSTACK
623 default n
624 help
625 Configure maximum number of CPUS and NUMA Nodes for this architecture.
626 If unsure, say N.
628 config NR_CPUS
629 int "Maximum number of CPUs" if SMP && !MAXSMP
630 range 2 512 if SMP && !MAXSMP
631 default "1" if !SMP
632 default "4096" if MAXSMP
633 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
634 default "8" if SMP
635 help
636 This allows you to specify the maximum number of CPUs which this
637 kernel will support. The maximum supported value is 512 and the
638 minimum value which makes sense is 2.
640 This is purely to save memory - each supported CPU adds
641 approximately eight kilobytes to the kernel image.
643 config SCHED_SMT
644 bool "SMT (Hyperthreading) scheduler support"
645 depends on X86_HT
646 help
647 SMT scheduler support improves the CPU scheduler's decision making
648 when dealing with Intel Pentium 4 chips with HyperThreading at a
649 cost of slightly increased overhead in some places. If unsure say
650 N here.
652 config SCHED_MC
653 def_bool y
654 prompt "Multi-core scheduler support"
655 depends on X86_HT
656 help
657 Multi-core scheduler support improves the CPU scheduler's decision
658 making when dealing with multi-core CPU chips at a cost of slightly
659 increased overhead in some places. If unsure say N here.
661 source "kernel/Kconfig.preempt"
663 config X86_UP_APIC
664 bool "Local APIC support on uniprocessors"
665 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
666 help
667 A local APIC (Advanced Programmable Interrupt Controller) is an
668 integrated interrupt controller in the CPU. If you have a single-CPU
669 system which has a processor with a local APIC, you can say Y here to
670 enable and use it. If you say Y here even though your machine doesn't
671 have a local APIC, then the kernel will still run with no slowdown at
672 all. The local APIC supports CPU-generated self-interrupts (timer,
673 performance counters), and the NMI watchdog which detects hard
674 lockups.
676 config X86_UP_IOAPIC
677 bool "IO-APIC support on uniprocessors"
678 depends on X86_UP_APIC
679 help
680 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
681 SMP-capable replacement for PC-style interrupt controllers. Most
682 SMP systems and many recent uniprocessor systems have one.
684 If you have a single-CPU system with an IO-APIC, you can say Y here
685 to use it. If you say Y here even though your machine doesn't have
686 an IO-APIC, then the kernel will still run with no slowdown at all.
688 config X86_LOCAL_APIC
689 def_bool y
690 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
692 config X86_IO_APIC
693 def_bool y
694 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
696 config X86_VISWS_APIC
697 def_bool y
698 depends on X86_32 && X86_VISWS
700 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
701 bool "Reroute for broken boot IRQs"
702 default n
703 depends on X86_IO_APIC
704 help
705 This option enables a workaround that fixes a source of
706 spurious interrupts. This is recommended when threaded
707 interrupt handling is used on systems where the generation of
708 superfluous "boot interrupts" cannot be disabled.
710 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
711 entry in the chipset's IO-APIC is masked (as, e.g. the RT
712 kernel does during interrupt handling). On chipsets where this
713 boot IRQ generation cannot be disabled, this workaround keeps
714 the original IRQ line masked so that only the equivalent "boot
715 IRQ" is delivered to the CPUs. The workaround also tells the
716 kernel to set up the IRQ handler on the boot IRQ line. In this
717 way only one interrupt is delivered to the kernel. Otherwise
718 the spurious second interrupt may cause the kernel to bring
719 down (vital) interrupt lines.
721 Only affects "broken" chipsets. Interrupt sharing may be
722 increased on these systems.
724 config X86_MCE
725 bool "Machine Check Exception"
726 depends on !X86_VOYAGER
727 ---help---
728 Machine Check Exception support allows the processor to notify the
729 kernel if it detects a problem (e.g. overheating, component failure).
730 The action the kernel takes depends on the severity of the problem,
731 ranging from a warning message on the console, to halting the machine.
732 Your processor must be a Pentium or newer to support this - check the
733 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
734 have a design flaw which leads to false MCE events - hence MCE is
735 disabled on all P5 processors, unless explicitly enabled with "mce"
736 as a boot argument. Similarly, if MCE is built in and creates a
737 problem on some new non-standard machine, you can boot with "nomce"
738 to disable it. MCE support simply ignores non-MCE processors like
739 the 386 and 486, so nearly everyone can say Y here.
741 config X86_MCE_INTEL
742 def_bool y
743 prompt "Intel MCE features"
744 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
745 help
746 Additional support for intel specific MCE features such as
747 the thermal monitor.
749 config X86_MCE_AMD
750 def_bool y
751 prompt "AMD MCE features"
752 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
753 help
754 Additional support for AMD specific MCE features such as
755 the DRAM Error Threshold.
757 config X86_MCE_NONFATAL
758 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
759 depends on X86_32 && X86_MCE
760 help
761 Enabling this feature starts a timer that triggers every 5 seconds which
762 will look at the machine check registers to see if anything happened.
763 Non-fatal problems automatically get corrected (but still logged).
764 Disable this if you don't want to see these messages.
765 Seeing the messages this option prints out may be indicative of dying
766 or out-of-spec (ie, overclocked) hardware.
767 This option only does something on certain CPUs.
768 (AMD Athlon/Duron and Intel Pentium 4)
770 config X86_MCE_P4THERMAL
771 bool "check for P4 thermal throttling interrupt."
772 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
773 help
774 Enabling this feature will cause a message to be printed when the P4
775 enters thermal throttling.
777 config VM86
778 bool "Enable VM86 support" if EMBEDDED
779 default y
780 depends on X86_32
781 help
782 This option is required by programs like DOSEMU to run 16-bit legacy
783 code on X86 processors. It also may be needed by software like
784 XFree86 to initialize some video cards via BIOS. Disabling this
785 option saves about 6k.
787 config TOSHIBA
788 tristate "Toshiba Laptop support"
789 depends on X86_32
790 ---help---
791 This adds a driver to safely access the System Management Mode of
792 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
793 not work on models with a Phoenix BIOS. The System Management Mode
794 is used to set the BIOS and power saving options on Toshiba portables.
796 For information on utilities to make use of this driver see the
797 Toshiba Linux utilities web site at:
798 <http://www.buzzard.org.uk/toshiba/>.
800 Say Y if you intend to run this kernel on a Toshiba portable.
801 Say N otherwise.
803 config I8K
804 tristate "Dell laptop support"
805 ---help---
806 This adds a driver to safely access the System Management Mode
807 of the CPU on the Dell Inspiron 8000. The System Management Mode
808 is used to read cpu temperature and cooling fan status and to
809 control the fans on the I8K portables.
811 This driver has been tested only on the Inspiron 8000 but it may
812 also work with other Dell laptops. You can force loading on other
813 models by passing the parameter `force=1' to the module. Use at
814 your own risk.
816 For information on utilities to make use of this driver see the
817 I8K Linux utilities web site at:
818 <http://people.debian.org/~dz/i8k/>
820 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
821 Say N otherwise.
823 config X86_REBOOTFIXUPS
824 bool "Enable X86 board specific fixups for reboot"
825 depends on X86_32
826 ---help---
827 This enables chipset and/or board specific fixups to be done
828 in order to get reboot to work correctly. This is only needed on
829 some combinations of hardware and BIOS. The symptom, for which
830 this config is intended, is when reboot ends with a stalled/hung
831 system.
833 Currently, the only fixup is for the Geode machines using
834 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
836 Say Y if you want to enable the fixup. Currently, it's safe to
837 enable this option even if you don't need it.
838 Say N otherwise.
840 config MICROCODE
841 tristate "/dev/cpu/microcode - microcode support"
842 select FW_LOADER
843 ---help---
844 If you say Y here, you will be able to update the microcode on
845 certain Intel and AMD processors. The Intel support is for the
846 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
847 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
848 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
849 You will obviously need the actual microcode binary data itself
850 which is not shipped with the Linux kernel.
852 This option selects the general module only, you need to select
853 at least one vendor specific module as well.
855 To compile this driver as a module, choose M here: the
856 module will be called microcode.
858 config MICROCODE_INTEL
859 bool "Intel microcode patch loading support"
860 depends on MICROCODE
861 default MICROCODE
862 select FW_LOADER
863 --help---
864 This options enables microcode patch loading support for Intel
865 processors.
867 For latest news and information on obtaining all the required
868 Intel ingredients for this driver, check:
869 <http://www.urbanmyth.org/microcode/>.
871 config MICROCODE_AMD
872 bool "AMD microcode patch loading support"
873 depends on MICROCODE
874 select FW_LOADER
875 --help---
876 If you select this option, microcode patch loading support for AMD
877 processors will be enabled.
879 config MICROCODE_OLD_INTERFACE
880 def_bool y
881 depends on MICROCODE
883 config X86_MSR
884 tristate "/dev/cpu/*/msr - Model-specific register support"
885 help
886 This device gives privileged processes access to the x86
887 Model-Specific Registers (MSRs). It is a character device with
888 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
889 MSR accesses are directed to a specific CPU on multi-processor
890 systems.
892 config X86_CPUID
893 tristate "/dev/cpu/*/cpuid - CPU information support"
894 help
895 This device gives processes access to the x86 CPUID instruction to
896 be executed on a specific processor. It is a character device
897 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
898 /dev/cpu/31/cpuid.
900 choice
901 prompt "High Memory Support"
902 default HIGHMEM4G if !X86_NUMAQ
903 default HIGHMEM64G if X86_NUMAQ
904 depends on X86_32
906 config NOHIGHMEM
907 bool "off"
908 depends on !X86_NUMAQ
909 ---help---
910 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
911 However, the address space of 32-bit x86 processors is only 4
912 Gigabytes large. That means that, if you have a large amount of
913 physical memory, not all of it can be "permanently mapped" by the
914 kernel. The physical memory that's not permanently mapped is called
915 "high memory".
917 If you are compiling a kernel which will never run on a machine with
918 more than 1 Gigabyte total physical RAM, answer "off" here (default
919 choice and suitable for most users). This will result in a "3GB/1GB"
920 split: 3GB are mapped so that each process sees a 3GB virtual memory
921 space and the remaining part of the 4GB virtual memory space is used
922 by the kernel to permanently map as much physical memory as
923 possible.
925 If the machine has between 1 and 4 Gigabytes physical RAM, then
926 answer "4GB" here.
928 If more than 4 Gigabytes is used then answer "64GB" here. This
929 selection turns Intel PAE (Physical Address Extension) mode on.
930 PAE implements 3-level paging on IA32 processors. PAE is fully
931 supported by Linux, PAE mode is implemented on all recent Intel
932 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
933 then the kernel will not boot on CPUs that don't support PAE!
935 The actual amount of total physical memory will either be
936 auto detected or can be forced by using a kernel command line option
937 such as "mem=256M". (Try "man bootparam" or see the documentation of
938 your boot loader (lilo or loadlin) about how to pass options to the
939 kernel at boot time.)
941 If unsure, say "off".
943 config HIGHMEM4G
944 bool "4GB"
945 depends on !X86_NUMAQ
946 help
947 Select this if you have a 32-bit processor and between 1 and 4
948 gigabytes of physical RAM.
950 config HIGHMEM64G
951 bool "64GB"
952 depends on !M386 && !M486
953 select X86_PAE
954 help
955 Select this if you have a 32-bit processor and more than 4
956 gigabytes of physical RAM.
958 endchoice
960 choice
961 depends on EXPERIMENTAL
962 prompt "Memory split" if EMBEDDED
963 default VMSPLIT_3G
964 depends on X86_32
965 help
966 Select the desired split between kernel and user memory.
968 If the address range available to the kernel is less than the
969 physical memory installed, the remaining memory will be available
970 as "high memory". Accessing high memory is a little more costly
971 than low memory, as it needs to be mapped into the kernel first.
972 Note that increasing the kernel address space limits the range
973 available to user programs, making the address space there
974 tighter. Selecting anything other than the default 3G/1G split
975 will also likely make your kernel incompatible with binary-only
976 kernel modules.
978 If you are not absolutely sure what you are doing, leave this
979 option alone!
981 config VMSPLIT_3G
982 bool "3G/1G user/kernel split"
983 config VMSPLIT_3G_OPT
984 depends on !X86_PAE
985 bool "3G/1G user/kernel split (for full 1G low memory)"
986 config VMSPLIT_2G
987 bool "2G/2G user/kernel split"
988 config VMSPLIT_2G_OPT
989 depends on !X86_PAE
990 bool "2G/2G user/kernel split (for full 2G low memory)"
991 config VMSPLIT_1G
992 bool "1G/3G user/kernel split"
993 endchoice
995 config PAGE_OFFSET
996 hex
997 default 0xB0000000 if VMSPLIT_3G_OPT
998 default 0x80000000 if VMSPLIT_2G
999 default 0x78000000 if VMSPLIT_2G_OPT
1000 default 0x40000000 if VMSPLIT_1G
1001 default 0xC0000000
1002 depends on X86_32
1004 config HIGHMEM
1005 def_bool y
1006 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1008 config X86_PAE
1009 bool "PAE (Physical Address Extension) Support"
1010 depends on X86_32 && !HIGHMEM4G
1011 help
1012 PAE is required for NX support, and furthermore enables
1013 larger swapspace support for non-overcommit purposes. It
1014 has the cost of more pagetable lookup overhead, and also
1015 consumes more pagetable space per process.
1017 config ARCH_PHYS_ADDR_T_64BIT
1018 def_bool X86_64 || X86_PAE
1020 config DIRECT_GBPAGES
1021 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1022 default y
1023 depends on X86_64
1024 help
1025 Allow the kernel linear mapping to use 1GB pages on CPUs that
1026 support it. This can improve the kernel's performance a tiny bit by
1027 reducing TLB pressure. If in doubt, say "Y".
1029 # Common NUMA Features
1030 config NUMA
1031 bool "Numa Memory Allocation and Scheduler Support"
1032 depends on SMP
1033 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1034 default n if X86_PC
1035 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1036 help
1037 Enable NUMA (Non Uniform Memory Access) support.
1039 The kernel will try to allocate memory used by a CPU on the
1040 local memory controller of the CPU and add some more
1041 NUMA awareness to the kernel.
1043 For 64-bit this is recommended if the system is Intel Core i7
1044 (or later), AMD Opteron, or EM64T NUMA.
1046 For 32-bit this is only needed on (rare) 32-bit-only platforms
1047 that support NUMA topologies, such as NUMAQ / Summit, or if you
1048 boot a 32-bit kernel on a 64-bit NUMA platform.
1050 Otherwise, you should say N.
1052 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1053 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1055 config K8_NUMA
1056 def_bool y
1057 prompt "Old style AMD Opteron NUMA detection"
1058 depends on X86_64 && NUMA && PCI
1059 help
1060 Enable K8 NUMA node topology detection. You should say Y here if
1061 you have a multi processor AMD K8 system. This uses an old
1062 method to read the NUMA configuration directly from the builtin
1063 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1064 instead, which also takes priority if both are compiled in.
1066 config X86_64_ACPI_NUMA
1067 def_bool y
1068 prompt "ACPI NUMA detection"
1069 depends on X86_64 && NUMA && ACPI && PCI
1070 select ACPI_NUMA
1071 help
1072 Enable ACPI SRAT based node topology detection.
1074 # Some NUMA nodes have memory ranges that span
1075 # other nodes. Even though a pfn is valid and
1076 # between a node's start and end pfns, it may not
1077 # reside on that node. See memmap_init_zone()
1078 # for details.
1079 config NODES_SPAN_OTHER_NODES
1080 def_bool y
1081 depends on X86_64_ACPI_NUMA
1083 config NUMA_EMU
1084 bool "NUMA emulation"
1085 depends on X86_64 && NUMA
1086 help
1087 Enable NUMA emulation. A flat machine will be split
1088 into virtual nodes when booted with "numa=fake=N", where N is the
1089 number of nodes. This is only useful for debugging.
1091 config NODES_SHIFT
1092 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1093 range 1 9 if X86_64
1094 default "9" if MAXSMP
1095 default "6" if X86_64
1096 default "4" if X86_NUMAQ
1097 default "3"
1098 depends on NEED_MULTIPLE_NODES
1099 help
1100 Specify the maximum number of NUMA Nodes available on the target
1101 system. Increases memory reserved to accomodate various tables.
1103 config HAVE_ARCH_BOOTMEM_NODE
1104 def_bool y
1105 depends on X86_32 && NUMA
1107 config ARCH_HAVE_MEMORY_PRESENT
1108 def_bool y
1109 depends on X86_32 && DISCONTIGMEM
1111 config NEED_NODE_MEMMAP_SIZE
1112 def_bool y
1113 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1115 config HAVE_ARCH_ALLOC_REMAP
1116 def_bool y
1117 depends on X86_32 && NUMA
1119 config ARCH_FLATMEM_ENABLE
1120 def_bool y
1121 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1123 config ARCH_DISCONTIGMEM_ENABLE
1124 def_bool y
1125 depends on NUMA && X86_32
1127 config ARCH_DISCONTIGMEM_DEFAULT
1128 def_bool y
1129 depends on NUMA && X86_32
1131 config ARCH_SPARSEMEM_DEFAULT
1132 def_bool y
1133 depends on X86_64
1135 config ARCH_SPARSEMEM_ENABLE
1136 def_bool y
1137 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1138 select SPARSEMEM_STATIC if X86_32
1139 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1141 config ARCH_SELECT_MEMORY_MODEL
1142 def_bool y
1143 depends on ARCH_SPARSEMEM_ENABLE
1145 config ARCH_MEMORY_PROBE
1146 def_bool X86_64
1147 depends on MEMORY_HOTPLUG
1149 source "mm/Kconfig"
1151 config HIGHPTE
1152 bool "Allocate 3rd-level pagetables from highmem"
1153 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1154 help
1155 The VM uses one page table entry for each page of physical memory.
1156 For systems with a lot of RAM, this can be wasteful of precious
1157 low memory. Setting this option will put user-space page table
1158 entries in high memory.
1160 config X86_CHECK_BIOS_CORRUPTION
1161 bool "Check for low memory corruption"
1162 help
1163 Periodically check for memory corruption in low memory, which
1164 is suspected to be caused by BIOS. Even when enabled in the
1165 configuration, it is disabled at runtime. Enable it by
1166 setting "memory_corruption_check=1" on the kernel command
1167 line. By default it scans the low 64k of memory every 60
1168 seconds; see the memory_corruption_check_size and
1169 memory_corruption_check_period parameters in
1170 Documentation/kernel-parameters.txt to adjust this.
1172 When enabled with the default parameters, this option has
1173 almost no overhead, as it reserves a relatively small amount
1174 of memory and scans it infrequently. It both detects corruption
1175 and prevents it from affecting the running system.
1177 It is, however, intended as a diagnostic tool; if repeatable
1178 BIOS-originated corruption always affects the same memory,
1179 you can use memmap= to prevent the kernel from using that
1180 memory.
1182 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1183 bool "Set the default setting of memory_corruption_check"
1184 depends on X86_CHECK_BIOS_CORRUPTION
1185 default y
1186 help
1187 Set whether the default state of memory_corruption_check is
1188 on or off.
1190 config X86_RESERVE_LOW_64K
1191 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1192 default y
1193 help
1194 Reserve the first 64K of physical RAM on BIOSes that are known
1195 to potentially corrupt that memory range. A numbers of BIOSes are
1196 known to utilize this area during suspend/resume, so it must not
1197 be used by the kernel.
1199 Set this to N if you are absolutely sure that you trust the BIOS
1200 to get all its memory reservations and usages right.
1202 If you have doubts about the BIOS (e.g. suspend/resume does not
1203 work or there's kernel crashes after certain hardware hotplug
1204 events) and it's not AMI or Phoenix, then you might want to enable
1205 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1206 corruption patterns.
1208 Say Y if unsure.
1210 config MATH_EMULATION
1211 bool
1212 prompt "Math emulation" if X86_32
1213 ---help---
1214 Linux can emulate a math coprocessor (used for floating point
1215 operations) if you don't have one. 486DX and Pentium processors have
1216 a math coprocessor built in, 486SX and 386 do not, unless you added
1217 a 487DX or 387, respectively. (The messages during boot time can
1218 give you some hints here ["man dmesg"].) Everyone needs either a
1219 coprocessor or this emulation.
1221 If you don't have a math coprocessor, you need to say Y here; if you
1222 say Y here even though you have a coprocessor, the coprocessor will
1223 be used nevertheless. (This behavior can be changed with the kernel
1224 command line option "no387", which comes handy if your coprocessor
1225 is broken. Try "man bootparam" or see the documentation of your boot
1226 loader (lilo or loadlin) about how to pass options to the kernel at
1227 boot time.) This means that it is a good idea to say Y here if you
1228 intend to use this kernel on different machines.
1230 More information about the internals of the Linux math coprocessor
1231 emulation can be found in <file:arch/x86/math-emu/README>.
1233 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1234 kernel, it won't hurt.
1236 config MTRR
1237 bool "MTRR (Memory Type Range Register) support"
1238 ---help---
1239 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1240 the Memory Type Range Registers (MTRRs) may be used to control
1241 processor access to memory ranges. This is most useful if you have
1242 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1243 allows bus write transfers to be combined into a larger transfer
1244 before bursting over the PCI/AGP bus. This can increase performance
1245 of image write operations 2.5 times or more. Saying Y here creates a
1246 /proc/mtrr file which may be used to manipulate your processor's
1247 MTRRs. Typically the X server should use this.
1249 This code has a reasonably generic interface so that similar
1250 control registers on other processors can be easily supported
1251 as well:
1253 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1254 Registers (ARRs) which provide a similar functionality to MTRRs. For
1255 these, the ARRs are used to emulate the MTRRs.
1256 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1257 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1258 write-combining. All of these processors are supported by this code
1259 and it makes sense to say Y here if you have one of them.
1261 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1262 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1263 can lead to all sorts of problems, so it's good to say Y here.
1265 You can safely say Y even if your machine doesn't have MTRRs, you'll
1266 just add about 9 KB to your kernel.
1268 See <file:Documentation/x86/mtrr.txt> for more information.
1270 config MTRR_SANITIZER
1271 def_bool y
1272 prompt "MTRR cleanup support"
1273 depends on MTRR
1274 help
1275 Convert MTRR layout from continuous to discrete, so X drivers can
1276 add writeback entries.
1278 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1279 The largest mtrr entry size for a continous block can be set with
1280 mtrr_chunk_size.
1282 If unsure, say Y.
1284 config MTRR_SANITIZER_ENABLE_DEFAULT
1285 int "MTRR cleanup enable value (0-1)"
1286 range 0 1
1287 default "0"
1288 depends on MTRR_SANITIZER
1289 help
1290 Enable mtrr cleanup default value
1292 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1293 int "MTRR cleanup spare reg num (0-7)"
1294 range 0 7
1295 default "1"
1296 depends on MTRR_SANITIZER
1297 help
1298 mtrr cleanup spare entries default, it can be changed via
1299 mtrr_spare_reg_nr=N on the kernel command line.
1301 config X86_PAT
1302 bool
1303 prompt "x86 PAT support"
1304 depends on MTRR
1305 help
1306 Use PAT attributes to setup page level cache control.
1308 PATs are the modern equivalents of MTRRs and are much more
1309 flexible than MTRRs.
1311 Say N here if you see bootup problems (boot crash, boot hang,
1312 spontaneous reboots) or a non-working video driver.
1314 If unsure, say Y.
1316 config EFI
1317 bool "EFI runtime service support"
1318 depends on ACPI
1319 ---help---
1320 This enables the kernel to use EFI runtime services that are
1321 available (such as the EFI variable services).
1323 This option is only useful on systems that have EFI firmware.
1324 In addition, you should use the latest ELILO loader available
1325 at <http://elilo.sourceforge.net> in order to take advantage
1326 of EFI runtime services. However, even with this option, the
1327 resultant kernel should continue to boot on existing non-EFI
1328 platforms.
1330 config SECCOMP
1331 def_bool y
1332 prompt "Enable seccomp to safely compute untrusted bytecode"
1333 help
1334 This kernel feature is useful for number crunching applications
1335 that may need to compute untrusted bytecode during their
1336 execution. By using pipes or other transports made available to
1337 the process as file descriptors supporting the read/write
1338 syscalls, it's possible to isolate those applications in
1339 their own address space using seccomp. Once seccomp is
1340 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1341 and the task is only allowed to execute a few safe syscalls
1342 defined by each seccomp mode.
1344 If unsure, say Y. Only embedded should say N here.
1346 config CC_STACKPROTECTOR
1347 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1348 depends on X86_64 && EXPERIMENTAL && BROKEN
1349 help
1350 This option turns on the -fstack-protector GCC feature. This
1351 feature puts, at the beginning of critical functions, a canary
1352 value on the stack just before the return address, and validates
1353 the value just before actually returning. Stack based buffer
1354 overflows (that need to overwrite this return address) now also
1355 overwrite the canary, which gets detected and the attack is then
1356 neutralized via a kernel panic.
1358 This feature requires gcc version 4.2 or above, or a distribution
1359 gcc with the feature backported. Older versions are automatically
1360 detected and for those versions, this configuration option is ignored.
1362 config CC_STACKPROTECTOR_ALL
1363 bool "Use stack-protector for all functions"
1364 depends on CC_STACKPROTECTOR
1365 help
1366 Normally, GCC only inserts the canary value protection for
1367 functions that use large-ish on-stack buffers. By enabling
1368 this option, GCC will be asked to do this for ALL functions.
1370 source kernel/Kconfig.hz
1372 config KEXEC
1373 bool "kexec system call"
1374 depends on X86_BIOS_REBOOT
1375 help
1376 kexec is a system call that implements the ability to shutdown your
1377 current kernel, and to start another kernel. It is like a reboot
1378 but it is independent of the system firmware. And like a reboot
1379 you can start any kernel with it, not just Linux.
1381 The name comes from the similarity to the exec system call.
1383 It is an ongoing process to be certain the hardware in a machine
1384 is properly shutdown, so do not be surprised if this code does not
1385 initially work for you. It may help to enable device hotplugging
1386 support. As of this writing the exact hardware interface is
1387 strongly in flux, so no good recommendation can be made.
1389 config CRASH_DUMP
1390 bool "kernel crash dumps"
1391 depends on X86_64 || (X86_32 && HIGHMEM)
1392 help
1393 Generate crash dump after being started by kexec.
1394 This should be normally only set in special crash dump kernels
1395 which are loaded in the main kernel with kexec-tools into
1396 a specially reserved region and then later executed after
1397 a crash by kdump/kexec. The crash dump kernel must be compiled
1398 to a memory address not used by the main kernel or BIOS using
1399 PHYSICAL_START, or it must be built as a relocatable image
1400 (CONFIG_RELOCATABLE=y).
1401 For more details see Documentation/kdump/kdump.txt
1403 config KEXEC_JUMP
1404 bool "kexec jump (EXPERIMENTAL)"
1405 depends on EXPERIMENTAL
1406 depends on KEXEC && HIBERNATION && X86_32
1407 help
1408 Jump between original kernel and kexeced kernel and invoke
1409 code in physical address mode via KEXEC
1411 config PHYSICAL_START
1412 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1413 default "0x1000000" if X86_NUMAQ
1414 default "0x200000" if X86_64
1415 default "0x100000"
1416 help
1417 This gives the physical address where the kernel is loaded.
1419 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1420 bzImage will decompress itself to above physical address and
1421 run from there. Otherwise, bzImage will run from the address where
1422 it has been loaded by the boot loader and will ignore above physical
1423 address.
1425 In normal kdump cases one does not have to set/change this option
1426 as now bzImage can be compiled as a completely relocatable image
1427 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1428 address. This option is mainly useful for the folks who don't want
1429 to use a bzImage for capturing the crash dump and want to use a
1430 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1431 to be specifically compiled to run from a specific memory area
1432 (normally a reserved region) and this option comes handy.
1434 So if you are using bzImage for capturing the crash dump, leave
1435 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1436 Otherwise if you plan to use vmlinux for capturing the crash dump
1437 change this value to start of the reserved region (Typically 16MB
1438 0x1000000). In other words, it can be set based on the "X" value as
1439 specified in the "crashkernel=YM@XM" command line boot parameter
1440 passed to the panic-ed kernel. Typically this parameter is set as
1441 crashkernel=64M@16M. Please take a look at
1442 Documentation/kdump/kdump.txt for more details about crash dumps.
1444 Usage of bzImage for capturing the crash dump is recommended as
1445 one does not have to build two kernels. Same kernel can be used
1446 as production kernel and capture kernel. Above option should have
1447 gone away after relocatable bzImage support is introduced. But it
1448 is present because there are users out there who continue to use
1449 vmlinux for dump capture. This option should go away down the
1450 line.
1452 Don't change this unless you know what you are doing.
1454 config RELOCATABLE
1455 bool "Build a relocatable kernel (EXPERIMENTAL)"
1456 depends on EXPERIMENTAL
1457 help
1458 This builds a kernel image that retains relocation information
1459 so it can be loaded someplace besides the default 1MB.
1460 The relocations tend to make the kernel binary about 10% larger,
1461 but are discarded at runtime.
1463 One use is for the kexec on panic case where the recovery kernel
1464 must live at a different physical address than the primary
1465 kernel.
1467 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1468 it has been loaded at and the compile time physical address
1469 (CONFIG_PHYSICAL_START) is ignored.
1471 config PHYSICAL_ALIGN
1472 hex
1473 prompt "Alignment value to which kernel should be aligned" if X86_32
1474 default "0x100000" if X86_32
1475 default "0x200000" if X86_64
1476 range 0x2000 0x400000
1477 help
1478 This value puts the alignment restrictions on physical address
1479 where kernel is loaded and run from. Kernel is compiled for an
1480 address which meets above alignment restriction.
1482 If bootloader loads the kernel at a non-aligned address and
1483 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1484 address aligned to above value and run from there.
1486 If bootloader loads the kernel at a non-aligned address and
1487 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1488 load address and decompress itself to the address it has been
1489 compiled for and run from there. The address for which kernel is
1490 compiled already meets above alignment restrictions. Hence the
1491 end result is that kernel runs from a physical address meeting
1492 above alignment restrictions.
1494 Don't change this unless you know what you are doing.
1496 config HOTPLUG_CPU
1497 bool "Support for hot-pluggable CPUs"
1498 depends on SMP && HOTPLUG && !X86_VOYAGER
1499 ---help---
1500 Say Y here to allow turning CPUs off and on. CPUs can be
1501 controlled through /sys/devices/system/cpu.
1502 ( Note: power management support will enable this option
1503 automatically on SMP systems. )
1504 Say N if you want to disable CPU hotplug.
1506 config COMPAT_VDSO
1507 def_bool y
1508 prompt "Compat VDSO support"
1509 depends on X86_32 || IA32_EMULATION
1510 help
1511 Map the 32-bit VDSO to the predictable old-style address too.
1512 ---help---
1513 Say N here if you are running a sufficiently recent glibc
1514 version (2.3.3 or later), to remove the high-mapped
1515 VDSO mapping and to exclusively use the randomized VDSO.
1517 If unsure, say Y.
1519 config CMDLINE_BOOL
1520 bool "Built-in kernel command line"
1521 default n
1522 help
1523 Allow for specifying boot arguments to the kernel at
1524 build time. On some systems (e.g. embedded ones), it is
1525 necessary or convenient to provide some or all of the
1526 kernel boot arguments with the kernel itself (that is,
1527 to not rely on the boot loader to provide them.)
1529 To compile command line arguments into the kernel,
1530 set this option to 'Y', then fill in the
1531 the boot arguments in CONFIG_CMDLINE.
1533 Systems with fully functional boot loaders (i.e. non-embedded)
1534 should leave this option set to 'N'.
1536 config CMDLINE
1537 string "Built-in kernel command string"
1538 depends on CMDLINE_BOOL
1539 default ""
1540 help
1541 Enter arguments here that should be compiled into the kernel
1542 image and used at boot time. If the boot loader provides a
1543 command line at boot time, it is appended to this string to
1544 form the full kernel command line, when the system boots.
1546 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1547 change this behavior.
1549 In most cases, the command line (whether built-in or provided
1550 by the boot loader) should specify the device for the root
1551 file system.
1553 config CMDLINE_OVERRIDE
1554 bool "Built-in command line overrides boot loader arguments"
1555 default n
1556 depends on CMDLINE_BOOL
1557 help
1558 Set this option to 'Y' to have the kernel ignore the boot loader
1559 command line, and use ONLY the built-in command line.
1561 This is used to work around broken boot loaders. This should
1562 be set to 'N' under normal conditions.
1564 endmenu
1566 config ARCH_ENABLE_MEMORY_HOTPLUG
1567 def_bool y
1568 depends on X86_64 || (X86_32 && HIGHMEM)
1570 config ARCH_ENABLE_MEMORY_HOTREMOVE
1571 def_bool y
1572 depends on MEMORY_HOTPLUG
1574 config HAVE_ARCH_EARLY_PFN_TO_NID
1575 def_bool X86_64
1576 depends on NUMA
1578 menu "Power management and ACPI options"
1579 depends on !X86_VOYAGER
1581 config ARCH_HIBERNATION_HEADER
1582 def_bool y
1583 depends on X86_64 && HIBERNATION
1585 source "kernel/power/Kconfig"
1587 source "drivers/acpi/Kconfig"
1589 config X86_APM_BOOT
1590 bool
1591 default y
1592 depends on APM || APM_MODULE
1594 menuconfig APM
1595 tristate "APM (Advanced Power Management) BIOS support"
1596 depends on X86_32 && PM_SLEEP
1597 ---help---
1598 APM is a BIOS specification for saving power using several different
1599 techniques. This is mostly useful for battery powered laptops with
1600 APM compliant BIOSes. If you say Y here, the system time will be
1601 reset after a RESUME operation, the /proc/apm device will provide
1602 battery status information, and user-space programs will receive
1603 notification of APM "events" (e.g. battery status change).
1605 If you select "Y" here, you can disable actual use of the APM
1606 BIOS by passing the "apm=off" option to the kernel at boot time.
1608 Note that the APM support is almost completely disabled for
1609 machines with more than one CPU.
1611 In order to use APM, you will need supporting software. For location
1612 and more information, read <file:Documentation/power/pm.txt> and the
1613 Battery Powered Linux mini-HOWTO, available from
1614 <http://www.tldp.org/docs.html#howto>.
1616 This driver does not spin down disk drives (see the hdparm(8)
1617 manpage ("man 8 hdparm") for that), and it doesn't turn off
1618 VESA-compliant "green" monitors.
1620 This driver does not support the TI 4000M TravelMate and the ACER
1621 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1622 desktop machines also don't have compliant BIOSes, and this driver
1623 may cause those machines to panic during the boot phase.
1625 Generally, if you don't have a battery in your machine, there isn't
1626 much point in using this driver and you should say N. If you get
1627 random kernel OOPSes or reboots that don't seem to be related to
1628 anything, try disabling/enabling this option (or disabling/enabling
1629 APM in your BIOS).
1631 Some other things you should try when experiencing seemingly random,
1632 "weird" problems:
1634 1) make sure that you have enough swap space and that it is
1635 enabled.
1636 2) pass the "no-hlt" option to the kernel
1637 3) switch on floating point emulation in the kernel and pass
1638 the "no387" option to the kernel
1639 4) pass the "floppy=nodma" option to the kernel
1640 5) pass the "mem=4M" option to the kernel (thereby disabling
1641 all but the first 4 MB of RAM)
1642 6) make sure that the CPU is not over clocked.
1643 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1644 8) disable the cache from your BIOS settings
1645 9) install a fan for the video card or exchange video RAM
1646 10) install a better fan for the CPU
1647 11) exchange RAM chips
1648 12) exchange the motherboard.
1650 To compile this driver as a module, choose M here: the
1651 module will be called apm.
1653 if APM
1655 config APM_IGNORE_USER_SUSPEND
1656 bool "Ignore USER SUSPEND"
1657 help
1658 This option will ignore USER SUSPEND requests. On machines with a
1659 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1660 series notebooks, it is necessary to say Y because of a BIOS bug.
1662 config APM_DO_ENABLE
1663 bool "Enable PM at boot time"
1664 ---help---
1665 Enable APM features at boot time. From page 36 of the APM BIOS
1666 specification: "When disabled, the APM BIOS does not automatically
1667 power manage devices, enter the Standby State, enter the Suspend
1668 State, or take power saving steps in response to CPU Idle calls."
1669 This driver will make CPU Idle calls when Linux is idle (unless this
1670 feature is turned off -- see "Do CPU IDLE calls", below). This
1671 should always save battery power, but more complicated APM features
1672 will be dependent on your BIOS implementation. You may need to turn
1673 this option off if your computer hangs at boot time when using APM
1674 support, or if it beeps continuously instead of suspending. Turn
1675 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1676 T400CDT. This is off by default since most machines do fine without
1677 this feature.
1679 config APM_CPU_IDLE
1680 bool "Make CPU Idle calls when idle"
1681 help
1682 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1683 On some machines, this can activate improved power savings, such as
1684 a slowed CPU clock rate, when the machine is idle. These idle calls
1685 are made after the idle loop has run for some length of time (e.g.,
1686 333 mS). On some machines, this will cause a hang at boot time or
1687 whenever the CPU becomes idle. (On machines with more than one CPU,
1688 this option does nothing.)
1690 config APM_DISPLAY_BLANK
1691 bool "Enable console blanking using APM"
1692 help
1693 Enable console blanking using the APM. Some laptops can use this to
1694 turn off the LCD backlight when the screen blanker of the Linux
1695 virtual console blanks the screen. Note that this is only used by
1696 the virtual console screen blanker, and won't turn off the backlight
1697 when using the X Window system. This also doesn't have anything to
1698 do with your VESA-compliant power-saving monitor. Further, this
1699 option doesn't work for all laptops -- it might not turn off your
1700 backlight at all, or it might print a lot of errors to the console,
1701 especially if you are using gpm.
1703 config APM_ALLOW_INTS
1704 bool "Allow interrupts during APM BIOS calls"
1705 help
1706 Normally we disable external interrupts while we are making calls to
1707 the APM BIOS as a measure to lessen the effects of a badly behaving
1708 BIOS implementation. The BIOS should reenable interrupts if it
1709 needs to. Unfortunately, some BIOSes do not -- especially those in
1710 many of the newer IBM Thinkpads. If you experience hangs when you
1711 suspend, try setting this to Y. Otherwise, say N.
1713 endif # APM
1715 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1717 source "drivers/cpuidle/Kconfig"
1719 source "drivers/idle/Kconfig"
1721 endmenu
1724 menu "Bus options (PCI etc.)"
1726 config PCI
1727 bool "PCI support"
1728 default y
1729 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1730 help
1731 Find out whether you have a PCI motherboard. PCI is the name of a
1732 bus system, i.e. the way the CPU talks to the other stuff inside
1733 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1734 VESA. If you have PCI, say Y, otherwise N.
1736 choice
1737 prompt "PCI access mode"
1738 depends on X86_32 && PCI
1739 default PCI_GOANY
1740 ---help---
1741 On PCI systems, the BIOS can be used to detect the PCI devices and
1742 determine their configuration. However, some old PCI motherboards
1743 have BIOS bugs and may crash if this is done. Also, some embedded
1744 PCI-based systems don't have any BIOS at all. Linux can also try to
1745 detect the PCI hardware directly without using the BIOS.
1747 With this option, you can specify how Linux should detect the
1748 PCI devices. If you choose "BIOS", the BIOS will be used,
1749 if you choose "Direct", the BIOS won't be used, and if you
1750 choose "MMConfig", then PCI Express MMCONFIG will be used.
1751 If you choose "Any", the kernel will try MMCONFIG, then the
1752 direct access method and falls back to the BIOS if that doesn't
1753 work. If unsure, go with the default, which is "Any".
1755 config PCI_GOBIOS
1756 bool "BIOS"
1758 config PCI_GOMMCONFIG
1759 bool "MMConfig"
1761 config PCI_GODIRECT
1762 bool "Direct"
1764 config PCI_GOOLPC
1765 bool "OLPC"
1766 depends on OLPC
1768 config PCI_GOANY
1769 bool "Any"
1771 endchoice
1773 config PCI_BIOS
1774 def_bool y
1775 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1777 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1778 config PCI_DIRECT
1779 def_bool y
1780 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1782 config PCI_MMCONFIG
1783 def_bool y
1784 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1786 config PCI_OLPC
1787 def_bool y
1788 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1790 config PCI_DOMAINS
1791 def_bool y
1792 depends on PCI
1794 config PCI_MMCONFIG
1795 bool "Support mmconfig PCI config space access"
1796 depends on X86_64 && PCI && ACPI
1798 config DMAR
1799 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1800 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1801 help
1802 DMA remapping (DMAR) devices support enables independent address
1803 translations for Direct Memory Access (DMA) from devices.
1804 These DMA remapping devices are reported via ACPI tables
1805 and include PCI device scope covered by these DMA
1806 remapping devices.
1808 config DMAR_DEFAULT_ON
1809 def_bool y
1810 prompt "Enable DMA Remapping Devices by default"
1811 depends on DMAR
1812 help
1813 Selecting this option will enable a DMAR device at boot time if
1814 one is found. If this option is not selected, DMAR support can
1815 be enabled by passing intel_iommu=on to the kernel. It is
1816 recommended you say N here while the DMAR code remains
1817 experimental.
1819 config DMAR_GFX_WA
1820 def_bool y
1821 prompt "Support for Graphics workaround"
1822 depends on DMAR
1823 help
1824 Current Graphics drivers tend to use physical address
1825 for DMA and avoid using DMA APIs. Setting this config
1826 option permits the IOMMU driver to set a unity map for
1827 all the OS-visible memory. Hence the driver can continue
1828 to use physical addresses for DMA.
1830 config DMAR_FLOPPY_WA
1831 def_bool y
1832 depends on DMAR
1833 help
1834 Floppy disk drivers are know to bypass DMA API calls
1835 thereby failing to work when IOMMU is enabled. This
1836 workaround will setup a 1:1 mapping for the first
1837 16M to make floppy (an ISA device) work.
1839 config INTR_REMAP
1840 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1841 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1842 help
1843 Supports Interrupt remapping for IO-APIC and MSI devices.
1844 To use x2apic mode in the CPU's which support x2APIC enhancements or
1845 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1847 source "drivers/pci/pcie/Kconfig"
1849 source "drivers/pci/Kconfig"
1851 # x86_64 have no ISA slots, but do have ISA-style DMA.
1852 config ISA_DMA_API
1853 def_bool y
1855 if X86_32
1857 config ISA
1858 bool "ISA support"
1859 depends on !X86_VOYAGER
1860 help
1861 Find out whether you have ISA slots on your motherboard. ISA is the
1862 name of a bus system, i.e. the way the CPU talks to the other stuff
1863 inside your box. Other bus systems are PCI, EISA, MicroChannel
1864 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1865 newer boards don't support it. If you have ISA, say Y, otherwise N.
1867 config EISA
1868 bool "EISA support"
1869 depends on ISA
1870 ---help---
1871 The Extended Industry Standard Architecture (EISA) bus was
1872 developed as an open alternative to the IBM MicroChannel bus.
1874 The EISA bus provided some of the features of the IBM MicroChannel
1875 bus while maintaining backward compatibility with cards made for
1876 the older ISA bus. The EISA bus saw limited use between 1988 and
1877 1995 when it was made obsolete by the PCI bus.
1879 Say Y here if you are building a kernel for an EISA-based machine.
1881 Otherwise, say N.
1883 source "drivers/eisa/Kconfig"
1885 config MCA
1886 bool "MCA support" if !X86_VOYAGER
1887 default y if X86_VOYAGER
1888 help
1889 MicroChannel Architecture is found in some IBM PS/2 machines and
1890 laptops. It is a bus system similar to PCI or ISA. See
1891 <file:Documentation/mca.txt> (and especially the web page given
1892 there) before attempting to build an MCA bus kernel.
1894 source "drivers/mca/Kconfig"
1896 config SCx200
1897 tristate "NatSemi SCx200 support"
1898 depends on !X86_VOYAGER
1899 help
1900 This provides basic support for National Semiconductor's
1901 (now AMD's) Geode processors. The driver probes for the
1902 PCI-IDs of several on-chip devices, so its a good dependency
1903 for other scx200_* drivers.
1905 If compiled as a module, the driver is named scx200.
1907 config SCx200HR_TIMER
1908 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1909 depends on SCx200 && GENERIC_TIME
1910 default y
1911 help
1912 This driver provides a clocksource built upon the on-chip
1913 27MHz high-resolution timer. Its also a workaround for
1914 NSC Geode SC-1100's buggy TSC, which loses time when the
1915 processor goes idle (as is done by the scheduler). The
1916 other workaround is idle=poll boot option.
1918 config GEODE_MFGPT_TIMER
1919 def_bool y
1920 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1921 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1922 help
1923 This driver provides a clock event source based on the MFGPT
1924 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1925 MFGPTs have a better resolution and max interval than the
1926 generic PIT, and are suitable for use as high-res timers.
1928 config OLPC
1929 bool "One Laptop Per Child support"
1930 default n
1931 help
1932 Add support for detecting the unique features of the OLPC
1933 XO hardware.
1935 endif # X86_32
1937 config K8_NB
1938 def_bool y
1939 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1941 source "drivers/pcmcia/Kconfig"
1943 source "drivers/pci/hotplug/Kconfig"
1945 endmenu
1948 menu "Executable file formats / Emulations"
1950 source "fs/Kconfig.binfmt"
1952 config IA32_EMULATION
1953 bool "IA32 Emulation"
1954 depends on X86_64
1955 select COMPAT_BINFMT_ELF
1956 help
1957 Include code to run 32-bit programs under a 64-bit kernel. You should
1958 likely turn this on, unless you're 100% sure that you don't have any
1959 32-bit programs left.
1961 config IA32_AOUT
1962 tristate "IA32 a.out support"
1963 depends on IA32_EMULATION
1964 help
1965 Support old a.out binaries in the 32bit emulation.
1967 config COMPAT
1968 def_bool y
1969 depends on IA32_EMULATION
1971 config COMPAT_FOR_U64_ALIGNMENT
1972 def_bool COMPAT
1973 depends on X86_64
1975 config SYSVIPC_COMPAT
1976 def_bool y
1977 depends on COMPAT && SYSVIPC
1979 endmenu
1982 config HAVE_ATOMIC_IOMAP
1983 def_bool y
1984 depends on X86_32
1986 source "net/Kconfig"
1988 source "drivers/Kconfig"
1990 source "drivers/firmware/Kconfig"
1992 source "fs/Kconfig"
1994 source "arch/x86/Kconfig.debug"
1996 source "security/Kconfig"
1998 source "crypto/Kconfig"
2000 source "arch/x86/kvm/Kconfig"
2002 source "lib/Kconfig"