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1 #
2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
4 #
6 mainmenu "Linux Kernel Configuration"
8 config X86_32
9 bool
10 default y
11 help
12 This is Linux's home port. Linux was originally native to the Intel
13 386, and runs on all the later x86 processors including the Intel
14 486, 586, Pentiums, and various instruction-set-compatible chips by
15 AMD, Cyrix, and others.
17 config GENERIC_TIME
18 bool
19 default y
21 config GENERIC_CMOS_UPDATE
22 bool
23 default y
25 config CLOCKSOURCE_WATCHDOG
26 bool
27 default y
29 config GENERIC_CLOCKEVENTS
30 bool
31 default y
33 config GENERIC_CLOCKEVENTS_BROADCAST
34 bool
35 default y
36 depends on X86_LOCAL_APIC
38 config LOCKDEP_SUPPORT
39 bool
40 default y
42 config STACKTRACE_SUPPORT
43 bool
44 default y
46 config SEMAPHORE_SLEEPERS
47 bool
48 default y
50 config X86
51 bool
52 default y
54 config MMU
55 bool
56 default y
58 config ZONE_DMA
59 bool
60 default y
62 config QUICKLIST
63 bool
64 default y
66 config SBUS
67 bool
69 config GENERIC_ISA_DMA
70 bool
71 default y
73 config GENERIC_IOMAP
74 bool
75 default y
77 config GENERIC_BUG
78 bool
79 default y
80 depends on BUG
82 config GENERIC_HWEIGHT
83 bool
84 default y
86 config ARCH_MAY_HAVE_PC_FDC
87 bool
88 default y
90 config DMI
91 bool
92 default y
94 source "init/Kconfig"
96 menu "Processor type and features"
98 source "kernel/time/Kconfig"
100 config SMP
101 bool "Symmetric multi-processing support"
102 ---help---
103 This enables support for systems with more than one CPU. If you have
104 a system with only one CPU, like most personal computers, say N. If
105 you have a system with more than one CPU, say Y.
107 If you say N here, the kernel will run on single and multiprocessor
108 machines, but will use only one CPU of a multiprocessor machine. If
109 you say Y here, the kernel will run on many, but not all,
110 singleprocessor machines. On a singleprocessor machine, the kernel
111 will run faster if you say N here.
113 Note that if you say Y here and choose architecture "586" or
114 "Pentium" under "Processor family", the kernel will not work on 486
115 architectures. Similarly, multiprocessor kernels for the "PPro"
116 architecture may not work on all Pentium based boards.
118 People using multiprocessor machines who say Y here should also say
119 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
120 Management" code will be disabled if you say Y here.
122 See also the <file:Documentation/smp.txt>,
123 <file:Documentation/i386/IO-APIC.txt>,
124 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
125 <http://www.tldp.org/docs.html#howto>.
127 If you don't know what to do here, say N.
129 choice
130 prompt "Subarchitecture Type"
131 default X86_PC
133 config X86_PC
134 bool "PC-compatible"
135 help
136 Choose this option if your computer is a standard PC or compatible.
138 config X86_ELAN
139 bool "AMD Elan"
140 help
141 Select this for an AMD Elan processor.
143 Do not use this option for K6/Athlon/Opteron processors!
145 If unsure, choose "PC-compatible" instead.
147 config X86_VOYAGER
148 bool "Voyager (NCR)"
149 select SMP if !BROKEN
150 help
151 Voyager is an MCA-based 32-way capable SMP architecture proprietary
152 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
154 *** WARNING ***
156 If you do not specifically know you have a Voyager based machine,
157 say N here, otherwise the kernel you build will not be bootable.
159 config X86_NUMAQ
160 bool "NUMAQ (IBM/Sequent)"
161 select SMP
162 select NUMA
163 help
164 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
165 multiquad box. This changes the way that processors are bootstrapped,
166 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
167 You will need a new lynxer.elf file to flash your firmware with - send
168 email to <Martin.Bligh@us.ibm.com>.
170 config X86_SUMMIT
171 bool "Summit/EXA (IBM x440)"
172 depends on SMP
173 help
174 This option is needed for IBM systems that use the Summit/EXA chipset.
175 In particular, it is needed for the x440.
177 If you don't have one of these computers, you should say N here.
178 If you want to build a NUMA kernel, you must select ACPI.
180 config X86_BIGSMP
181 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
182 depends on SMP
183 help
184 This option is needed for the systems that have more than 8 CPUs
185 and if the system is not of any sub-arch type above.
187 If you don't have such a system, you should say N here.
189 config X86_VISWS
190 bool "SGI 320/540 (Visual Workstation)"
191 help
192 The SGI Visual Workstation series is an IA32-based workstation
193 based on SGI systems chips with some legacy PC hardware attached.
195 Say Y here to create a kernel to run on the SGI 320 or 540.
197 A kernel compiled for the Visual Workstation will not run on PCs
198 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
200 config X86_GENERICARCH
201 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
202 help
203 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
204 It is intended for a generic binary kernel.
205 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
207 config X86_ES7000
208 bool "Support for Unisys ES7000 IA32 series"
209 depends on SMP
210 help
211 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
212 supposed to run on an IA32-based Unisys ES7000 system.
213 Only choose this option if you have such a system, otherwise you
214 should say N here.
216 endchoice
218 config SCHED_NO_NO_OMIT_FRAME_POINTER
219 bool "Single-depth WCHAN output"
220 default y
221 help
222 Calculate simpler /proc/<PID>/wchan values. If this option
223 is disabled then wchan values will recurse back to the
224 caller function. This provides more accurate wchan values,
225 at the expense of slightly more scheduling overhead.
227 If in doubt, say "Y".
229 config PARAVIRT
230 bool "Paravirtualization support (EXPERIMENTAL)"
231 depends on EXPERIMENTAL
232 depends on !(X86_VISWS || X86_VOYAGER)
233 help
234 Paravirtualization is a way of running multiple instances of
235 Linux on the same machine, under a hypervisor. This option
236 changes the kernel so it can modify itself when it is run
237 under a hypervisor, improving performance significantly.
238 However, when run without a hypervisor the kernel is
239 theoretically slower. If in doubt, say N.
241 source "arch/x86/xen/Kconfig"
243 config VMI
244 bool "VMI Paravirt-ops support"
245 depends on PARAVIRT
246 help
247 VMI provides a paravirtualized interface to the VMware ESX server
248 (it could be used by other hypervisors in theory too, but is not
249 at the moment), by linking the kernel to a GPL-ed ROM module
250 provided by the hypervisor.
252 config ACPI_SRAT
253 bool
254 default y
255 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
256 select ACPI_NUMA
258 config HAVE_ARCH_PARSE_SRAT
259 bool
260 default y
261 depends on ACPI_SRAT
263 config X86_SUMMIT_NUMA
264 bool
265 default y
266 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
268 config X86_CYCLONE_TIMER
269 bool
270 default y
271 depends on X86_SUMMIT || X86_GENERICARCH
273 config ES7000_CLUSTERED_APIC
274 bool
275 default y
276 depends on SMP && X86_ES7000 && MPENTIUMIII
278 source "arch/i386/Kconfig.cpu"
280 config HPET_TIMER
281 bool "HPET Timer Support"
282 help
283 This enables the use of the HPET for the kernel's internal timer.
284 HPET is the next generation timer replacing legacy 8254s.
285 You can safely choose Y here. However, HPET will only be
286 activated if the platform and the BIOS support this feature.
287 Otherwise the 8254 will be used for timing services.
289 Choose N to continue using the legacy 8254 timer.
291 config HPET_EMULATE_RTC
292 bool
293 depends on HPET_TIMER && RTC=y
294 default y
296 config NR_CPUS
297 int "Maximum number of CPUs (2-255)"
298 range 2 255
299 depends on SMP
300 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
301 default "8"
302 help
303 This allows you to specify the maximum number of CPUs which this
304 kernel will support. The maximum supported value is 255 and the
305 minimum value which makes sense is 2.
307 This is purely to save memory - each supported CPU adds
308 approximately eight kilobytes to the kernel image.
310 config SCHED_SMT
311 bool "SMT (Hyperthreading) scheduler support"
312 depends on X86_HT
313 help
314 SMT scheduler support improves the CPU scheduler's decision making
315 when dealing with Intel Pentium 4 chips with HyperThreading at a
316 cost of slightly increased overhead in some places. If unsure say
317 N here.
319 config SCHED_MC
320 bool "Multi-core scheduler support"
321 depends on X86_HT
322 default y
323 help
324 Multi-core scheduler support improves the CPU scheduler's decision
325 making when dealing with multi-core CPU chips at a cost of slightly
326 increased overhead in some places. If unsure say N here.
328 source "kernel/Kconfig.preempt"
330 config X86_UP_APIC
331 bool "Local APIC support on uniprocessors"
332 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
333 help
334 A local APIC (Advanced Programmable Interrupt Controller) is an
335 integrated interrupt controller in the CPU. If you have a single-CPU
336 system which has a processor with a local APIC, you can say Y here to
337 enable and use it. If you say Y here even though your machine doesn't
338 have a local APIC, then the kernel will still run with no slowdown at
339 all. The local APIC supports CPU-generated self-interrupts (timer,
340 performance counters), and the NMI watchdog which detects hard
341 lockups.
343 config X86_UP_IOAPIC
344 bool "IO-APIC support on uniprocessors"
345 depends on X86_UP_APIC
346 help
347 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
348 SMP-capable replacement for PC-style interrupt controllers. Most
349 SMP systems and many recent uniprocessor systems have one.
351 If you have a single-CPU system with an IO-APIC, you can say Y here
352 to use it. If you say Y here even though your machine doesn't have
353 an IO-APIC, then the kernel will still run with no slowdown at all.
355 config X86_LOCAL_APIC
356 bool
357 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
358 default y
360 config X86_IO_APIC
361 bool
362 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
363 default y
365 config X86_VISWS_APIC
366 bool
367 depends on X86_VISWS
368 default y
370 config X86_MCE
371 bool "Machine Check Exception"
372 depends on !X86_VOYAGER
373 ---help---
374 Machine Check Exception support allows the processor to notify the
375 kernel if it detects a problem (e.g. overheating, component failure).
376 The action the kernel takes depends on the severity of the problem,
377 ranging from a warning message on the console, to halting the machine.
378 Your processor must be a Pentium or newer to support this - check the
379 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
380 have a design flaw which leads to false MCE events - hence MCE is
381 disabled on all P5 processors, unless explicitly enabled with "mce"
382 as a boot argument. Similarly, if MCE is built in and creates a
383 problem on some new non-standard machine, you can boot with "nomce"
384 to disable it. MCE support simply ignores non-MCE processors like
385 the 386 and 486, so nearly everyone can say Y here.
387 config X86_MCE_NONFATAL
388 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
389 depends on X86_MCE
390 help
391 Enabling this feature starts a timer that triggers every 5 seconds which
392 will look at the machine check registers to see if anything happened.
393 Non-fatal problems automatically get corrected (but still logged).
394 Disable this if you don't want to see these messages.
395 Seeing the messages this option prints out may be indicative of dying hardware,
396 or out-of-spec (ie, overclocked) hardware.
397 This option only does something on certain CPUs.
398 (AMD Athlon/Duron and Intel Pentium 4)
400 config X86_MCE_P4THERMAL
401 bool "check for P4 thermal throttling interrupt."
402 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
403 help
404 Enabling this feature will cause a message to be printed when the P4
405 enters thermal throttling.
407 config VM86
408 default y
409 bool "Enable VM86 support" if EMBEDDED
410 help
411 This option is required by programs like DOSEMU to run 16-bit legacy
412 code on X86 processors. It also may be needed by software like
413 XFree86 to initialize some video cards via BIOS. Disabling this
414 option saves about 6k.
416 config TOSHIBA
417 tristate "Toshiba Laptop support"
418 ---help---
419 This adds a driver to safely access the System Management Mode of
420 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
421 not work on models with a Phoenix BIOS. The System Management Mode
422 is used to set the BIOS and power saving options on Toshiba portables.
424 For information on utilities to make use of this driver see the
425 Toshiba Linux utilities web site at:
426 <http://www.buzzard.org.uk/toshiba/>.
428 Say Y if you intend to run this kernel on a Toshiba portable.
429 Say N otherwise.
431 config I8K
432 tristate "Dell laptop support"
433 ---help---
434 This adds a driver to safely access the System Management Mode
435 of the CPU on the Dell Inspiron 8000. The System Management Mode
436 is used to read cpu temperature and cooling fan status and to
437 control the fans on the I8K portables.
439 This driver has been tested only on the Inspiron 8000 but it may
440 also work with other Dell laptops. You can force loading on other
441 models by passing the parameter `force=1' to the module. Use at
442 your own risk.
444 For information on utilities to make use of this driver see the
445 I8K Linux utilities web site at:
446 <http://people.debian.org/~dz/i8k/>
448 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
449 Say N otherwise.
451 config X86_REBOOTFIXUPS
452 bool "Enable X86 board specific fixups for reboot"
453 depends on X86
454 default n
455 ---help---
456 This enables chipset and/or board specific fixups to be done
457 in order to get reboot to work correctly. This is only needed on
458 some combinations of hardware and BIOS. The symptom, for which
459 this config is intended, is when reboot ends with a stalled/hung
460 system.
462 Currently, the only fixup is for the Geode machines using
463 CS5530A and CS5536 chipsets.
465 Say Y if you want to enable the fixup. Currently, it's safe to
466 enable this option even if you don't need it.
467 Say N otherwise.
469 config MICROCODE
470 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
471 select FW_LOADER
472 ---help---
473 If you say Y here, you will be able to update the microcode on
474 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
475 Pentium III, Pentium 4, Xeon etc. You will obviously need the
476 actual microcode binary data itself which is not shipped with the
477 Linux kernel.
479 For latest news and information on obtaining all the required
480 ingredients for this driver, check:
481 <http://www.urbanmyth.org/microcode/>.
483 To compile this driver as a module, choose M here: the
484 module will be called microcode.
486 config MICROCODE_OLD_INTERFACE
487 bool
488 depends on MICROCODE
489 default y
491 config X86_MSR
492 tristate "/dev/cpu/*/msr - Model-specific register support"
493 help
494 This device gives privileged processes access to the x86
495 Model-Specific Registers (MSRs). It is a character device with
496 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
497 MSR accesses are directed to a specific CPU on multi-processor
498 systems.
500 config X86_CPUID
501 tristate "/dev/cpu/*/cpuid - CPU information support"
502 help
503 This device gives processes access to the x86 CPUID instruction to
504 be executed on a specific processor. It is a character device
505 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
506 /dev/cpu/31/cpuid.
508 source "drivers/firmware/Kconfig"
510 choice
511 prompt "High Memory Support"
512 default HIGHMEM4G if !X86_NUMAQ
513 default HIGHMEM64G if X86_NUMAQ
515 config NOHIGHMEM
516 bool "off"
517 depends on !X86_NUMAQ
518 ---help---
519 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
520 However, the address space of 32-bit x86 processors is only 4
521 Gigabytes large. That means that, if you have a large amount of
522 physical memory, not all of it can be "permanently mapped" by the
523 kernel. The physical memory that's not permanently mapped is called
524 "high memory".
526 If you are compiling a kernel which will never run on a machine with
527 more than 1 Gigabyte total physical RAM, answer "off" here (default
528 choice and suitable for most users). This will result in a "3GB/1GB"
529 split: 3GB are mapped so that each process sees a 3GB virtual memory
530 space and the remaining part of the 4GB virtual memory space is used
531 by the kernel to permanently map as much physical memory as
532 possible.
534 If the machine has between 1 and 4 Gigabytes physical RAM, then
535 answer "4GB" here.
537 If more than 4 Gigabytes is used then answer "64GB" here. This
538 selection turns Intel PAE (Physical Address Extension) mode on.
539 PAE implements 3-level paging on IA32 processors. PAE is fully
540 supported by Linux, PAE mode is implemented on all recent Intel
541 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
542 then the kernel will not boot on CPUs that don't support PAE!
544 The actual amount of total physical memory will either be
545 auto detected or can be forced by using a kernel command line option
546 such as "mem=256M". (Try "man bootparam" or see the documentation of
547 your boot loader (lilo or loadlin) about how to pass options to the
548 kernel at boot time.)
550 If unsure, say "off".
552 config HIGHMEM4G
553 bool "4GB"
554 depends on !X86_NUMAQ
555 help
556 Select this if you have a 32-bit processor and between 1 and 4
557 gigabytes of physical RAM.
559 config HIGHMEM64G
560 bool "64GB"
561 depends on !M386 && !M486
562 select X86_PAE
563 help
564 Select this if you have a 32-bit processor and more than 4
565 gigabytes of physical RAM.
567 endchoice
569 choice
570 depends on EXPERIMENTAL
571 prompt "Memory split" if EMBEDDED
572 default VMSPLIT_3G
573 help
574 Select the desired split between kernel and user memory.
576 If the address range available to the kernel is less than the
577 physical memory installed, the remaining memory will be available
578 as "high memory". Accessing high memory is a little more costly
579 than low memory, as it needs to be mapped into the kernel first.
580 Note that increasing the kernel address space limits the range
581 available to user programs, making the address space there
582 tighter. Selecting anything other than the default 3G/1G split
583 will also likely make your kernel incompatible with binary-only
584 kernel modules.
586 If you are not absolutely sure what you are doing, leave this
587 option alone!
589 config VMSPLIT_3G
590 bool "3G/1G user/kernel split"
591 config VMSPLIT_3G_OPT
592 depends on !X86_PAE
593 bool "3G/1G user/kernel split (for full 1G low memory)"
594 config VMSPLIT_2G
595 bool "2G/2G user/kernel split"
596 config VMSPLIT_2G_OPT
597 depends on !X86_PAE
598 bool "2G/2G user/kernel split (for full 2G low memory)"
599 config VMSPLIT_1G
600 bool "1G/3G user/kernel split"
601 endchoice
603 config PAGE_OFFSET
604 hex
605 default 0xB0000000 if VMSPLIT_3G_OPT
606 default 0x80000000 if VMSPLIT_2G
607 default 0x78000000 if VMSPLIT_2G_OPT
608 default 0x40000000 if VMSPLIT_1G
609 default 0xC0000000
611 config HIGHMEM
612 bool
613 depends on HIGHMEM64G || HIGHMEM4G
614 default y
616 config X86_PAE
617 bool "PAE (Physical Address Extension) Support"
618 default n
619 depends on !HIGHMEM4G
620 select RESOURCES_64BIT
621 help
622 PAE is required for NX support, and furthermore enables
623 larger swapspace support for non-overcommit purposes. It
624 has the cost of more pagetable lookup overhead, and also
625 consumes more pagetable space per process.
627 # Common NUMA Features
628 config NUMA
629 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
630 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL
631 default n if X86_PC
632 default y if (X86_NUMAQ || X86_SUMMIT)
633 help
634 NUMA support for i386. This is currently high experimental
635 and should be only used for kernel development. It might also
636 cause boot failures.
638 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
639 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
641 config NODES_SHIFT
642 int
643 default "4" if X86_NUMAQ
644 default "3"
645 depends on NEED_MULTIPLE_NODES
647 config HAVE_ARCH_BOOTMEM_NODE
648 bool
649 depends on NUMA
650 default y
652 config ARCH_HAVE_MEMORY_PRESENT
653 bool
654 depends on DISCONTIGMEM
655 default y
657 config NEED_NODE_MEMMAP_SIZE
658 bool
659 depends on DISCONTIGMEM || SPARSEMEM
660 default y
662 config HAVE_ARCH_ALLOC_REMAP
663 bool
664 depends on NUMA
665 default y
667 config ARCH_FLATMEM_ENABLE
668 def_bool y
669 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
671 config ARCH_DISCONTIGMEM_ENABLE
672 def_bool y
673 depends on NUMA
675 config ARCH_DISCONTIGMEM_DEFAULT
676 def_bool y
677 depends on NUMA
679 config ARCH_SPARSEMEM_ENABLE
680 def_bool y
681 depends on (NUMA || (X86_PC && EXPERIMENTAL))
682 select SPARSEMEM_STATIC
684 config ARCH_SELECT_MEMORY_MODEL
685 def_bool y
686 depends on ARCH_SPARSEMEM_ENABLE
688 config ARCH_POPULATES_NODE_MAP
689 def_bool y
691 source "mm/Kconfig"
693 config HIGHPTE
694 bool "Allocate 3rd-level pagetables from highmem"
695 depends on HIGHMEM4G || HIGHMEM64G
696 help
697 The VM uses one page table entry for each page of physical memory.
698 For systems with a lot of RAM, this can be wasteful of precious
699 low memory. Setting this option will put user-space page table
700 entries in high memory.
702 config MATH_EMULATION
703 bool "Math emulation"
704 ---help---
705 Linux can emulate a math coprocessor (used for floating point
706 operations) if you don't have one. 486DX and Pentium processors have
707 a math coprocessor built in, 486SX and 386 do not, unless you added
708 a 487DX or 387, respectively. (The messages during boot time can
709 give you some hints here ["man dmesg"].) Everyone needs either a
710 coprocessor or this emulation.
712 If you don't have a math coprocessor, you need to say Y here; if you
713 say Y here even though you have a coprocessor, the coprocessor will
714 be used nevertheless. (This behavior can be changed with the kernel
715 command line option "no387", which comes handy if your coprocessor
716 is broken. Try "man bootparam" or see the documentation of your boot
717 loader (lilo or loadlin) about how to pass options to the kernel at
718 boot time.) This means that it is a good idea to say Y here if you
719 intend to use this kernel on different machines.
721 More information about the internals of the Linux math coprocessor
722 emulation can be found in <file:arch/x86/math-emu/README>.
724 If you are not sure, say Y; apart from resulting in a 66 KB bigger
725 kernel, it won't hurt.
727 config MTRR
728 bool "MTRR (Memory Type Range Register) support"
729 ---help---
730 On Intel P6 family processors (Pentium Pro, Pentium II and later)
731 the Memory Type Range Registers (MTRRs) may be used to control
732 processor access to memory ranges. This is most useful if you have
733 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
734 allows bus write transfers to be combined into a larger transfer
735 before bursting over the PCI/AGP bus. This can increase performance
736 of image write operations 2.5 times or more. Saying Y here creates a
737 /proc/mtrr file which may be used to manipulate your processor's
738 MTRRs. Typically the X server should use this.
740 This code has a reasonably generic interface so that similar
741 control registers on other processors can be easily supported
742 as well:
744 The Cyrix 6x86, 6x86MX and M II processors have Address Range
745 Registers (ARRs) which provide a similar functionality to MTRRs. For
746 these, the ARRs are used to emulate the MTRRs.
747 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
748 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
749 write-combining. All of these processors are supported by this code
750 and it makes sense to say Y here if you have one of them.
752 Saying Y here also fixes a problem with buggy SMP BIOSes which only
753 set the MTRRs for the boot CPU and not for the secondary CPUs. This
754 can lead to all sorts of problems, so it's good to say Y here.
756 You can safely say Y even if your machine doesn't have MTRRs, you'll
757 just add about 9 KB to your kernel.
759 See <file:Documentation/mtrr.txt> for more information.
761 config EFI
762 bool "Boot from EFI support"
763 depends on ACPI
764 default n
765 ---help---
766 This enables the kernel to boot on EFI platforms using
767 system configuration information passed to it from the firmware.
768 This also enables the kernel to use any EFI runtime services that are
769 available (such as the EFI variable services).
771 This option is only useful on systems that have EFI firmware
772 and will result in a kernel image that is ~8k larger. In addition,
773 you must use the latest ELILO loader available at
774 <http://elilo.sourceforge.net> in order to take advantage of
775 kernel initialization using EFI information (neither GRUB nor LILO know
776 anything about EFI). However, even with this option, the resultant
777 kernel should continue to boot on existing non-EFI platforms.
779 config IRQBALANCE
780 bool "Enable kernel irq balancing"
781 depends on SMP && X86_IO_APIC
782 default y
783 help
784 The default yes will allow the kernel to do irq load balancing.
785 Saying no will keep the kernel from doing irq load balancing.
787 # turning this on wastes a bunch of space.
788 # Summit needs it only when NUMA is on
789 config BOOT_IOREMAP
790 bool
791 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
792 default y
794 config SECCOMP
795 bool "Enable seccomp to safely compute untrusted bytecode"
796 depends on PROC_FS
797 default y
798 help
799 This kernel feature is useful for number crunching applications
800 that may need to compute untrusted bytecode during their
801 execution. By using pipes or other transports made available to
802 the process as file descriptors supporting the read/write
803 syscalls, it's possible to isolate those applications in
804 their own address space using seccomp. Once seccomp is
805 enabled via /proc/<pid>/seccomp, it cannot be disabled
806 and the task is only allowed to execute a few safe syscalls
807 defined by each seccomp mode.
809 If unsure, say Y. Only embedded should say N here.
811 source kernel/Kconfig.hz
813 config KEXEC
814 bool "kexec system call"
815 help
816 kexec is a system call that implements the ability to shutdown your
817 current kernel, and to start another kernel. It is like a reboot
818 but it is independent of the system firmware. And like a reboot
819 you can start any kernel with it, not just Linux.
821 The name comes from the similarity to the exec system call.
823 It is an ongoing process to be certain the hardware in a machine
824 is properly shutdown, so do not be surprised if this code does not
825 initially work for you. It may help to enable device hotplugging
826 support. As of this writing the exact hardware interface is
827 strongly in flux, so no good recommendation can be made.
829 config CRASH_DUMP
830 bool "kernel crash dumps (EXPERIMENTAL)"
831 depends on EXPERIMENTAL
832 depends on HIGHMEM
833 help
834 Generate crash dump after being started by kexec.
835 This should be normally only set in special crash dump kernels
836 which are loaded in the main kernel with kexec-tools into
837 a specially reserved region and then later executed after
838 a crash by kdump/kexec. The crash dump kernel must be compiled
839 to a memory address not used by the main kernel or BIOS using
840 PHYSICAL_START, or it must be built as a relocatable image
841 (CONFIG_RELOCATABLE=y).
842 For more details see Documentation/kdump/kdump.txt
844 config PHYSICAL_START
845 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
846 default "0x1000000" if X86_NUMAQ
847 default "0x100000"
848 help
849 This gives the physical address where the kernel is loaded.
851 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
852 bzImage will decompress itself to above physical address and
853 run from there. Otherwise, bzImage will run from the address where
854 it has been loaded by the boot loader and will ignore above physical
855 address.
857 In normal kdump cases one does not have to set/change this option
858 as now bzImage can be compiled as a completely relocatable image
859 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
860 address. This option is mainly useful for the folks who don't want
861 to use a bzImage for capturing the crash dump and want to use a
862 vmlinux instead. vmlinux is not relocatable hence a kernel needs
863 to be specifically compiled to run from a specific memory area
864 (normally a reserved region) and this option comes handy.
866 So if you are using bzImage for capturing the crash dump, leave
867 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
868 Otherwise if you plan to use vmlinux for capturing the crash dump
869 change this value to start of the reserved region (Typically 16MB
870 0x1000000). In other words, it can be set based on the "X" value as
871 specified in the "crashkernel=YM@XM" command line boot parameter
872 passed to the panic-ed kernel. Typically this parameter is set as
873 crashkernel=64M@16M. Please take a look at
874 Documentation/kdump/kdump.txt for more details about crash dumps.
876 Usage of bzImage for capturing the crash dump is recommended as
877 one does not have to build two kernels. Same kernel can be used
878 as production kernel and capture kernel. Above option should have
879 gone away after relocatable bzImage support is introduced. But it
880 is present because there are users out there who continue to use
881 vmlinux for dump capture. This option should go away down the
882 line.
884 Don't change this unless you know what you are doing.
886 config RELOCATABLE
887 bool "Build a relocatable kernel (EXPERIMENTAL)"
888 depends on EXPERIMENTAL
889 help
890 This builds a kernel image that retains relocation information
891 so it can be loaded someplace besides the default 1MB.
892 The relocations tend to make the kernel binary about 10% larger,
893 but are discarded at runtime.
895 One use is for the kexec on panic case where the recovery kernel
896 must live at a different physical address than the primary
897 kernel.
899 config PHYSICAL_ALIGN
900 hex "Alignment value to which kernel should be aligned"
901 default "0x100000"
902 range 0x2000 0x400000
903 help
904 This value puts the alignment restrictions on physical address
905 where kernel is loaded and run from. Kernel is compiled for an
906 address which meets above alignment restriction.
908 If bootloader loads the kernel at a non-aligned address and
909 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
910 address aligned to above value and run from there.
912 If bootloader loads the kernel at a non-aligned address and
913 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
914 load address and decompress itself to the address it has been
915 compiled for and run from there. The address for which kernel is
916 compiled already meets above alignment restrictions. Hence the
917 end result is that kernel runs from a physical address meeting
918 above alignment restrictions.
920 Don't change this unless you know what you are doing.
922 config HOTPLUG_CPU
923 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
924 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
925 ---help---
926 Say Y here to experiment with turning CPUs off and on, and to
927 enable suspend on SMP systems. CPUs can be controlled through
928 /sys/devices/system/cpu.
930 config COMPAT_VDSO
931 bool "Compat VDSO support"
932 default y
933 help
934 Map the VDSO to the predictable old-style address too.
935 ---help---
936 Say N here if you are running a sufficiently recent glibc
937 version (2.3.3 or later), to remove the high-mapped
938 VDSO mapping and to exclusively use the randomized VDSO.
940 If unsure, say Y.
942 endmenu
944 config ARCH_ENABLE_MEMORY_HOTPLUG
945 def_bool y
946 depends on HIGHMEM
948 menu "Power management options (ACPI, APM)"
949 depends on !X86_VOYAGER
951 source kernel/power/Kconfig
953 source "drivers/acpi/Kconfig"
955 menuconfig APM
956 tristate "APM (Advanced Power Management) BIOS support"
957 depends on PM_SLEEP && !X86_VISWS
958 ---help---
959 APM is a BIOS specification for saving power using several different
960 techniques. This is mostly useful for battery powered laptops with
961 APM compliant BIOSes. If you say Y here, the system time will be
962 reset after a RESUME operation, the /proc/apm device will provide
963 battery status information, and user-space programs will receive
964 notification of APM "events" (e.g. battery status change).
966 If you select "Y" here, you can disable actual use of the APM
967 BIOS by passing the "apm=off" option to the kernel at boot time.
969 Note that the APM support is almost completely disabled for
970 machines with more than one CPU.
972 In order to use APM, you will need supporting software. For location
973 and more information, read <file:Documentation/pm.txt> and the
974 Battery Powered Linux mini-HOWTO, available from
975 <http://www.tldp.org/docs.html#howto>.
977 This driver does not spin down disk drives (see the hdparm(8)
978 manpage ("man 8 hdparm") for that), and it doesn't turn off
979 VESA-compliant "green" monitors.
981 This driver does not support the TI 4000M TravelMate and the ACER
982 486/DX4/75 because they don't have compliant BIOSes. Many "green"
983 desktop machines also don't have compliant BIOSes, and this driver
984 may cause those machines to panic during the boot phase.
986 Generally, if you don't have a battery in your machine, there isn't
987 much point in using this driver and you should say N. If you get
988 random kernel OOPSes or reboots that don't seem to be related to
989 anything, try disabling/enabling this option (or disabling/enabling
990 APM in your BIOS).
992 Some other things you should try when experiencing seemingly random,
993 "weird" problems:
995 1) make sure that you have enough swap space and that it is
996 enabled.
997 2) pass the "no-hlt" option to the kernel
998 3) switch on floating point emulation in the kernel and pass
999 the "no387" option to the kernel
1000 4) pass the "floppy=nodma" option to the kernel
1001 5) pass the "mem=4M" option to the kernel (thereby disabling
1002 all but the first 4 MB of RAM)
1003 6) make sure that the CPU is not over clocked.
1004 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1005 8) disable the cache from your BIOS settings
1006 9) install a fan for the video card or exchange video RAM
1007 10) install a better fan for the CPU
1008 11) exchange RAM chips
1009 12) exchange the motherboard.
1011 To compile this driver as a module, choose M here: the
1012 module will be called apm.
1014 if APM
1016 config APM_IGNORE_USER_SUSPEND
1017 bool "Ignore USER SUSPEND"
1018 help
1019 This option will ignore USER SUSPEND requests. On machines with a
1020 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1021 series notebooks, it is necessary to say Y because of a BIOS bug.
1023 config APM_DO_ENABLE
1024 bool "Enable PM at boot time"
1025 ---help---
1026 Enable APM features at boot time. From page 36 of the APM BIOS
1027 specification: "When disabled, the APM BIOS does not automatically
1028 power manage devices, enter the Standby State, enter the Suspend
1029 State, or take power saving steps in response to CPU Idle calls."
1030 This driver will make CPU Idle calls when Linux is idle (unless this
1031 feature is turned off -- see "Do CPU IDLE calls", below). This
1032 should always save battery power, but more complicated APM features
1033 will be dependent on your BIOS implementation. You may need to turn
1034 this option off if your computer hangs at boot time when using APM
1035 support, or if it beeps continuously instead of suspending. Turn
1036 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1037 T400CDT. This is off by default since most machines do fine without
1038 this feature.
1040 config APM_CPU_IDLE
1041 bool "Make CPU Idle calls when idle"
1042 help
1043 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1044 On some machines, this can activate improved power savings, such as
1045 a slowed CPU clock rate, when the machine is idle. These idle calls
1046 are made after the idle loop has run for some length of time (e.g.,
1047 333 mS). On some machines, this will cause a hang at boot time or
1048 whenever the CPU becomes idle. (On machines with more than one CPU,
1049 this option does nothing.)
1051 config APM_DISPLAY_BLANK
1052 bool "Enable console blanking using APM"
1053 help
1054 Enable console blanking using the APM. Some laptops can use this to
1055 turn off the LCD backlight when the screen blanker of the Linux
1056 virtual console blanks the screen. Note that this is only used by
1057 the virtual console screen blanker, and won't turn off the backlight
1058 when using the X Window system. This also doesn't have anything to
1059 do with your VESA-compliant power-saving monitor. Further, this
1060 option doesn't work for all laptops -- it might not turn off your
1061 backlight at all, or it might print a lot of errors to the console,
1062 especially if you are using gpm.
1064 config APM_ALLOW_INTS
1065 bool "Allow interrupts during APM BIOS calls"
1066 help
1067 Normally we disable external interrupts while we are making calls to
1068 the APM BIOS as a measure to lessen the effects of a badly behaving
1069 BIOS implementation. The BIOS should reenable interrupts if it
1070 needs to. Unfortunately, some BIOSes do not -- especially those in
1071 many of the newer IBM Thinkpads. If you experience hangs when you
1072 suspend, try setting this to Y. Otherwise, say N.
1074 config APM_REAL_MODE_POWER_OFF
1075 bool "Use real mode APM BIOS call to power off"
1076 help
1077 Use real mode APM BIOS calls to switch off the computer. This is
1078 a work-around for a number of buggy BIOSes. Switch this option on if
1079 your computer crashes instead of powering off properly.
1081 endif # APM
1083 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1085 endmenu
1087 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1089 config PCI
1090 bool "PCI support" if !X86_VISWS
1091 depends on !X86_VOYAGER
1092 default y if X86_VISWS
1093 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1094 help
1095 Find out whether you have a PCI motherboard. PCI is the name of a
1096 bus system, i.e. the way the CPU talks to the other stuff inside
1097 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1098 VESA. If you have PCI, say Y, otherwise N.
1100 The PCI-HOWTO, available from
1101 <http://www.tldp.org/docs.html#howto>, contains valuable
1102 information about which PCI hardware does work under Linux and which
1103 doesn't.
1105 choice
1106 prompt "PCI access mode"
1107 depends on PCI && !X86_VISWS
1108 default PCI_GOANY
1109 ---help---
1110 On PCI systems, the BIOS can be used to detect the PCI devices and
1111 determine their configuration. However, some old PCI motherboards
1112 have BIOS bugs and may crash if this is done. Also, some embedded
1113 PCI-based systems don't have any BIOS at all. Linux can also try to
1114 detect the PCI hardware directly without using the BIOS.
1116 With this option, you can specify how Linux should detect the
1117 PCI devices. If you choose "BIOS", the BIOS will be used,
1118 if you choose "Direct", the BIOS won't be used, and if you
1119 choose "MMConfig", then PCI Express MMCONFIG will be used.
1120 If you choose "Any", the kernel will try MMCONFIG, then the
1121 direct access method and falls back to the BIOS if that doesn't
1122 work. If unsure, go with the default, which is "Any".
1124 config PCI_GOBIOS
1125 bool "BIOS"
1127 config PCI_GOMMCONFIG
1128 bool "MMConfig"
1130 config PCI_GODIRECT
1131 bool "Direct"
1133 config PCI_GOANY
1134 bool "Any"
1136 endchoice
1138 config PCI_BIOS
1139 bool
1140 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1141 default y
1143 config PCI_DIRECT
1144 bool
1145 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1146 default y
1148 config PCI_MMCONFIG
1149 bool
1150 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1151 default y
1153 config PCI_DOMAINS
1154 bool
1155 depends on PCI
1156 default y
1158 source "drivers/pci/pcie/Kconfig"
1160 source "drivers/pci/Kconfig"
1162 config ISA_DMA_API
1163 bool
1164 default y
1166 config ISA
1167 bool "ISA support"
1168 depends on !(X86_VOYAGER || X86_VISWS)
1169 help
1170 Find out whether you have ISA slots on your motherboard. ISA is the
1171 name of a bus system, i.e. the way the CPU talks to the other stuff
1172 inside your box. Other bus systems are PCI, EISA, MicroChannel
1173 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1174 newer boards don't support it. If you have ISA, say Y, otherwise N.
1176 config EISA
1177 bool "EISA support"
1178 depends on ISA
1179 ---help---
1180 The Extended Industry Standard Architecture (EISA) bus was
1181 developed as an open alternative to the IBM MicroChannel bus.
1183 The EISA bus provided some of the features of the IBM MicroChannel
1184 bus while maintaining backward compatibility with cards made for
1185 the older ISA bus. The EISA bus saw limited use between 1988 and
1186 1995 when it was made obsolete by the PCI bus.
1188 Say Y here if you are building a kernel for an EISA-based machine.
1190 Otherwise, say N.
1192 source "drivers/eisa/Kconfig"
1194 config MCA
1195 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1196 default y if X86_VOYAGER
1197 help
1198 MicroChannel Architecture is found in some IBM PS/2 machines and
1199 laptops. It is a bus system similar to PCI or ISA. See
1200 <file:Documentation/mca.txt> (and especially the web page given
1201 there) before attempting to build an MCA bus kernel.
1203 source "drivers/mca/Kconfig"
1205 config SCx200
1206 tristate "NatSemi SCx200 support"
1207 depends on !X86_VOYAGER
1208 help
1209 This provides basic support for National Semiconductor's
1210 (now AMD's) Geode processors. The driver probes for the
1211 PCI-IDs of several on-chip devices, so its a good dependency
1212 for other scx200_* drivers.
1214 If compiled as a module, the driver is named scx200.
1216 config SCx200HR_TIMER
1217 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1218 depends on SCx200 && GENERIC_TIME
1219 default y
1220 help
1221 This driver provides a clocksource built upon the on-chip
1222 27MHz high-resolution timer. Its also a workaround for
1223 NSC Geode SC-1100's buggy TSC, which loses time when the
1224 processor goes idle (as is done by the scheduler). The
1225 other workaround is idle=poll boot option.
1227 config GEODE_MFGPT_TIMER
1228 bool "Geode Multi-Function General Purpose Timer (MFGPT) events"
1229 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1230 default y
1231 help
1232 This driver provides a clock event source based on the MFGPT
1233 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1234 MFGPTs have a better resolution and max interval than the
1235 generic PIT, and are suitable for use as high-res timers.
1237 config K8_NB
1238 def_bool y
1239 depends on AGP_AMD64
1241 source "drivers/pcmcia/Kconfig"
1243 source "drivers/pci/hotplug/Kconfig"
1245 endmenu
1247 menu "Executable file formats"
1249 source "fs/Kconfig.binfmt"
1251 endmenu
1253 source "net/Kconfig"
1255 source "drivers/Kconfig"
1257 source "fs/Kconfig"
1259 menuconfig INSTRUMENTATION
1260 bool "Instrumentation Support"
1261 default y
1262 ---help---
1263 Say Y here to get to see options related to performance measurement,
1264 debugging, and testing. This option alone does not add any kernel code.
1266 If you say N, all options in this submenu will be skipped and disabled.
1268 if INSTRUMENTATION
1270 source "arch/x86/oprofile/Kconfig"
1272 config KPROBES
1273 bool "Kprobes"
1274 depends on KALLSYMS && MODULES
1275 help
1276 Kprobes allows you to trap at almost any kernel address and
1277 execute a callback function. register_kprobe() establishes
1278 a probepoint and specifies the callback. Kprobes is useful
1279 for kernel debugging, non-intrusive instrumentation and testing.
1280 If in doubt, say "N".
1282 endif # INSTRUMENTATION
1284 source "arch/i386/Kconfig.debug"
1286 source "security/Kconfig"
1288 source "crypto/Kconfig"
1290 source "lib/Kconfig"
1292 #
1293 # Use the generic interrupt handling code in kernel/irq/:
1294 #
1295 config GENERIC_HARDIRQS
1296 bool
1297 default y
1299 config GENERIC_IRQ_PROBE
1300 bool
1301 default y
1303 config GENERIC_PENDING_IRQ
1304 bool
1305 depends on GENERIC_HARDIRQS && SMP
1306 default y
1308 config X86_SMP
1309 bool
1310 depends on SMP && !X86_VOYAGER
1311 default y
1313 config X86_HT
1314 bool
1315 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1316 default y
1318 config X86_BIOS_REBOOT
1319 bool
1320 depends on !(X86_VISWS || X86_VOYAGER)
1321 default y
1323 config X86_TRAMPOLINE
1324 bool
1325 depends on X86_SMP || (X86_VOYAGER && SMP)
1326 default y
1328 config KTIME_SCALAR
1329 bool
1330 default y