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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 help
150 Voyager is an MCA-based 32-way capable SMP architecture proprietary
151 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
153 *** WARNING ***
155 If you do not specifically know you have a Voyager based machine,
156 say N here, otherwise the kernel you build will not be bootable.
158 config X86_NUMAQ
159 bool "NUMAQ (IBM/Sequent)"
160 select SMP
161 select NUMA
162 help
163 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
164 multiquad box. This changes the way that processors are bootstrapped,
165 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
166 You will need a new lynxer.elf file to flash your firmware with - send
167 email to <Martin.Bligh@us.ibm.com>.
169 config X86_SUMMIT
170 bool "Summit/EXA (IBM x440)"
171 depends on SMP
172 help
173 This option is needed for IBM systems that use the Summit/EXA chipset.
174 In particular, it is needed for the x440.
176 If you don't have one of these computers, you should say N here.
177 If you want to build a NUMA kernel, you must select ACPI.
179 config X86_BIGSMP
180 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
181 depends on SMP
182 help
183 This option is needed for the systems that have more than 8 CPUs
184 and if the system is not of any sub-arch type above.
186 If you don't have such a system, you should say N here.
188 config X86_VISWS
189 bool "SGI 320/540 (Visual Workstation)"
190 help
191 The SGI Visual Workstation series is an IA32-based workstation
192 based on SGI systems chips with some legacy PC hardware attached.
194 Say Y here to create a kernel to run on the SGI 320 or 540.
196 A kernel compiled for the Visual Workstation will not run on PCs
197 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
199 config X86_GENERICARCH
200 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
201 help
202 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
203 It is intended for a generic binary kernel.
204 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
206 config X86_ES7000
207 bool "Support for Unisys ES7000 IA32 series"
208 depends on SMP
209 help
210 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
211 supposed to run on an IA32-based Unisys ES7000 system.
212 Only choose this option if you have such a system, otherwise you
213 should say N here.
215 endchoice
217 config SCHED_NO_NO_OMIT_FRAME_POINTER
218 bool "Single-depth WCHAN output"
219 default y
220 help
221 Calculate simpler /proc/<PID>/wchan values. If this option
222 is disabled then wchan values will recurse back to the
223 caller function. This provides more accurate wchan values,
224 at the expense of slightly more scheduling overhead.
226 If in doubt, say "Y".
228 config PARAVIRT
229 bool "Paravirtualization support (EXPERIMENTAL)"
230 depends on EXPERIMENTAL
231 depends on !(X86_VISWS || X86_VOYAGER)
232 help
233 Paravirtualization is a way of running multiple instances of
234 Linux on the same machine, under a hypervisor. This option
235 changes the kernel so it can modify itself when it is run
236 under a hypervisor, improving performance significantly.
237 However, when run without a hypervisor the kernel is
238 theoretically slower. If in doubt, say N.
240 source "arch/x86/xen/Kconfig"
242 config VMI
243 bool "VMI Paravirt-ops support"
244 depends on PARAVIRT
245 help
246 VMI provides a paravirtualized interface to the VMware ESX server
247 (it could be used by other hypervisors in theory too, but is not
248 at the moment), by linking the kernel to a GPL-ed ROM module
249 provided by the hypervisor.
251 config ACPI_SRAT
252 bool
253 default y
254 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
255 select ACPI_NUMA
257 config HAVE_ARCH_PARSE_SRAT
258 bool
259 default y
260 depends on ACPI_SRAT
262 config X86_SUMMIT_NUMA
263 bool
264 default y
265 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
267 config X86_CYCLONE_TIMER
268 bool
269 default y
270 depends on X86_SUMMIT || X86_GENERICARCH
272 config ES7000_CLUSTERED_APIC
273 bool
274 default y
275 depends on SMP && X86_ES7000 && MPENTIUMIII
277 source "arch/i386/Kconfig.cpu"
279 config HPET_TIMER
280 bool "HPET Timer Support"
281 help
282 This enables the use of the HPET for the kernel's internal timer.
283 HPET is the next generation timer replacing legacy 8254s.
284 You can safely choose Y here. However, HPET will only be
285 activated if the platform and the BIOS support this feature.
286 Otherwise the 8254 will be used for timing services.
288 Choose N to continue using the legacy 8254 timer.
290 config HPET_EMULATE_RTC
291 bool
292 depends on HPET_TIMER && RTC=y
293 default y
295 config NR_CPUS
296 int "Maximum number of CPUs (2-255)"
297 range 2 255
298 depends on SMP
299 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
300 default "8"
301 help
302 This allows you to specify the maximum number of CPUs which this
303 kernel will support. The maximum supported value is 255 and the
304 minimum value which makes sense is 2.
306 This is purely to save memory - each supported CPU adds
307 approximately eight kilobytes to the kernel image.
309 config SCHED_SMT
310 bool "SMT (Hyperthreading) scheduler support"
311 depends on X86_HT
312 help
313 SMT scheduler support improves the CPU scheduler's decision making
314 when dealing with Intel Pentium 4 chips with HyperThreading at a
315 cost of slightly increased overhead in some places. If unsure say
316 N here.
318 config SCHED_MC
319 bool "Multi-core scheduler support"
320 depends on X86_HT
321 default y
322 help
323 Multi-core scheduler support improves the CPU scheduler's decision
324 making when dealing with multi-core CPU chips at a cost of slightly
325 increased overhead in some places. If unsure say N here.
327 source "kernel/Kconfig.preempt"
329 config X86_UP_APIC
330 bool "Local APIC support on uniprocessors"
331 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
332 help
333 A local APIC (Advanced Programmable Interrupt Controller) is an
334 integrated interrupt controller in the CPU. If you have a single-CPU
335 system which has a processor with a local APIC, you can say Y here to
336 enable and use it. If you say Y here even though your machine doesn't
337 have a local APIC, then the kernel will still run with no slowdown at
338 all. The local APIC supports CPU-generated self-interrupts (timer,
339 performance counters), and the NMI watchdog which detects hard
340 lockups.
342 config X86_UP_IOAPIC
343 bool "IO-APIC support on uniprocessors"
344 depends on X86_UP_APIC
345 help
346 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
347 SMP-capable replacement for PC-style interrupt controllers. Most
348 SMP systems and many recent uniprocessor systems have one.
350 If you have a single-CPU system with an IO-APIC, you can say Y here
351 to use it. If you say Y here even though your machine doesn't have
352 an IO-APIC, then the kernel will still run with no slowdown at all.
354 config X86_LOCAL_APIC
355 bool
356 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
357 default y
359 config X86_IO_APIC
360 bool
361 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
362 default y
364 config X86_VISWS_APIC
365 bool
366 depends on X86_VISWS
367 default y
369 config X86_MCE
370 bool "Machine Check Exception"
371 depends on !X86_VOYAGER
372 ---help---
373 Machine Check Exception support allows the processor to notify the
374 kernel if it detects a problem (e.g. overheating, component failure).
375 The action the kernel takes depends on the severity of the problem,
376 ranging from a warning message on the console, to halting the machine.
377 Your processor must be a Pentium or newer to support this - check the
378 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
379 have a design flaw which leads to false MCE events - hence MCE is
380 disabled on all P5 processors, unless explicitly enabled with "mce"
381 as a boot argument. Similarly, if MCE is built in and creates a
382 problem on some new non-standard machine, you can boot with "nomce"
383 to disable it. MCE support simply ignores non-MCE processors like
384 the 386 and 486, so nearly everyone can say Y here.
386 config X86_MCE_NONFATAL
387 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
388 depends on X86_MCE
389 help
390 Enabling this feature starts a timer that triggers every 5 seconds which
391 will look at the machine check registers to see if anything happened.
392 Non-fatal problems automatically get corrected (but still logged).
393 Disable this if you don't want to see these messages.
394 Seeing the messages this option prints out may be indicative of dying hardware,
395 or out-of-spec (ie, overclocked) hardware.
396 This option only does something on certain CPUs.
397 (AMD Athlon/Duron and Intel Pentium 4)
399 config X86_MCE_P4THERMAL
400 bool "check for P4 thermal throttling interrupt."
401 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
402 help
403 Enabling this feature will cause a message to be printed when the P4
404 enters thermal throttling.
406 config VM86
407 default y
408 bool "Enable VM86 support" if EMBEDDED
409 help
410 This option is required by programs like DOSEMU to run 16-bit legacy
411 code on X86 processors. It also may be needed by software like
412 XFree86 to initialize some video cards via BIOS. Disabling this
413 option saves about 6k.
415 config TOSHIBA
416 tristate "Toshiba Laptop support"
417 ---help---
418 This adds a driver to safely access the System Management Mode of
419 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
420 not work on models with a Phoenix BIOS. The System Management Mode
421 is used to set the BIOS and power saving options on Toshiba portables.
423 For information on utilities to make use of this driver see the
424 Toshiba Linux utilities web site at:
425 <http://www.buzzard.org.uk/toshiba/>.
427 Say Y if you intend to run this kernel on a Toshiba portable.
428 Say N otherwise.
430 config I8K
431 tristate "Dell laptop support"
432 ---help---
433 This adds a driver to safely access the System Management Mode
434 of the CPU on the Dell Inspiron 8000. The System Management Mode
435 is used to read cpu temperature and cooling fan status and to
436 control the fans on the I8K portables.
438 This driver has been tested only on the Inspiron 8000 but it may
439 also work with other Dell laptops. You can force loading on other
440 models by passing the parameter `force=1' to the module. Use at
441 your own risk.
443 For information on utilities to make use of this driver see the
444 I8K Linux utilities web site at:
445 <http://people.debian.org/~dz/i8k/>
447 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
448 Say N otherwise.
450 config X86_REBOOTFIXUPS
451 bool "Enable X86 board specific fixups for reboot"
452 depends on X86
453 default n
454 ---help---
455 This enables chipset and/or board specific fixups to be done
456 in order to get reboot to work correctly. This is only needed on
457 some combinations of hardware and BIOS. The symptom, for which
458 this config is intended, is when reboot ends with a stalled/hung
459 system.
461 Currently, the only fixup is for the Geode machines using
462 CS5530A and CS5536 chipsets.
464 Say Y if you want to enable the fixup. Currently, it's safe to
465 enable this option even if you don't need it.
466 Say N otherwise.
468 config MICROCODE
469 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
470 select FW_LOADER
471 ---help---
472 If you say Y here, you will be able to update the microcode on
473 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
474 Pentium III, Pentium 4, Xeon etc. You will obviously need the
475 actual microcode binary data itself which is not shipped with the
476 Linux kernel.
478 For latest news and information on obtaining all the required
479 ingredients for this driver, check:
480 <http://www.urbanmyth.org/microcode/>.
482 To compile this driver as a module, choose M here: the
483 module will be called microcode.
485 config MICROCODE_OLD_INTERFACE
486 bool
487 depends on MICROCODE
488 default y
490 config X86_MSR
491 tristate "/dev/cpu/*/msr - Model-specific register support"
492 help
493 This device gives privileged processes access to the x86
494 Model-Specific Registers (MSRs). It is a character device with
495 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
496 MSR accesses are directed to a specific CPU on multi-processor
497 systems.
499 config X86_CPUID
500 tristate "/dev/cpu/*/cpuid - CPU information support"
501 help
502 This device gives processes access to the x86 CPUID instruction to
503 be executed on a specific processor. It is a character device
504 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
505 /dev/cpu/31/cpuid.
507 source "drivers/firmware/Kconfig"
509 choice
510 prompt "High Memory Support"
511 default HIGHMEM4G if !X86_NUMAQ
512 default HIGHMEM64G if X86_NUMAQ
514 config NOHIGHMEM
515 bool "off"
516 depends on !X86_NUMAQ
517 ---help---
518 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
519 However, the address space of 32-bit x86 processors is only 4
520 Gigabytes large. That means that, if you have a large amount of
521 physical memory, not all of it can be "permanently mapped" by the
522 kernel. The physical memory that's not permanently mapped is called
523 "high memory".
525 If you are compiling a kernel which will never run on a machine with
526 more than 1 Gigabyte total physical RAM, answer "off" here (default
527 choice and suitable for most users). This will result in a "3GB/1GB"
528 split: 3GB are mapped so that each process sees a 3GB virtual memory
529 space and the remaining part of the 4GB virtual memory space is used
530 by the kernel to permanently map as much physical memory as
531 possible.
533 If the machine has between 1 and 4 Gigabytes physical RAM, then
534 answer "4GB" here.
536 If more than 4 Gigabytes is used then answer "64GB" here. This
537 selection turns Intel PAE (Physical Address Extension) mode on.
538 PAE implements 3-level paging on IA32 processors. PAE is fully
539 supported by Linux, PAE mode is implemented on all recent Intel
540 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
541 then the kernel will not boot on CPUs that don't support PAE!
543 The actual amount of total physical memory will either be
544 auto detected or can be forced by using a kernel command line option
545 such as "mem=256M". (Try "man bootparam" or see the documentation of
546 your boot loader (lilo or loadlin) about how to pass options to the
547 kernel at boot time.)
549 If unsure, say "off".
551 config HIGHMEM4G
552 bool "4GB"
553 depends on !X86_NUMAQ
554 help
555 Select this if you have a 32-bit processor and between 1 and 4
556 gigabytes of physical RAM.
558 config HIGHMEM64G
559 bool "64GB"
560 depends on !M386 && !M486
561 select X86_PAE
562 help
563 Select this if you have a 32-bit processor and more than 4
564 gigabytes of physical RAM.
566 endchoice
568 choice
569 depends on EXPERIMENTAL
570 prompt "Memory split" if EMBEDDED
571 default VMSPLIT_3G
572 help
573 Select the desired split between kernel and user memory.
575 If the address range available to the kernel is less than the
576 physical memory installed, the remaining memory will be available
577 as "high memory". Accessing high memory is a little more costly
578 than low memory, as it needs to be mapped into the kernel first.
579 Note that increasing the kernel address space limits the range
580 available to user programs, making the address space there
581 tighter. Selecting anything other than the default 3G/1G split
582 will also likely make your kernel incompatible with binary-only
583 kernel modules.
585 If you are not absolutely sure what you are doing, leave this
586 option alone!
588 config VMSPLIT_3G
589 bool "3G/1G user/kernel split"
590 config VMSPLIT_3G_OPT
591 depends on !X86_PAE
592 bool "3G/1G user/kernel split (for full 1G low memory)"
593 config VMSPLIT_2G
594 bool "2G/2G user/kernel split"
595 config VMSPLIT_2G_OPT
596 depends on !X86_PAE
597 bool "2G/2G user/kernel split (for full 2G low memory)"
598 config VMSPLIT_1G
599 bool "1G/3G user/kernel split"
600 endchoice
602 config PAGE_OFFSET
603 hex
604 default 0xB0000000 if VMSPLIT_3G_OPT
605 default 0x80000000 if VMSPLIT_2G
606 default 0x78000000 if VMSPLIT_2G_OPT
607 default 0x40000000 if VMSPLIT_1G
608 default 0xC0000000
610 config HIGHMEM
611 bool
612 depends on HIGHMEM64G || HIGHMEM4G
613 default y
615 config X86_PAE
616 bool "PAE (Physical Address Extension) Support"
617 default n
618 depends on !HIGHMEM4G
619 select RESOURCES_64BIT
620 help
621 PAE is required for NX support, and furthermore enables
622 larger swapspace support for non-overcommit purposes. It
623 has the cost of more pagetable lookup overhead, and also
624 consumes more pagetable space per process.
626 # Common NUMA Features
627 config NUMA
628 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
629 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL
630 default n if X86_PC
631 default y if (X86_NUMAQ || X86_SUMMIT)
632 help
633 NUMA support for i386. This is currently high experimental
634 and should be only used for kernel development. It might also
635 cause boot failures.
637 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
638 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
640 config NODES_SHIFT
641 int
642 default "4" if X86_NUMAQ
643 default "3"
644 depends on NEED_MULTIPLE_NODES
646 config HAVE_ARCH_BOOTMEM_NODE
647 bool
648 depends on NUMA
649 default y
651 config ARCH_HAVE_MEMORY_PRESENT
652 bool
653 depends on DISCONTIGMEM
654 default y
656 config NEED_NODE_MEMMAP_SIZE
657 bool
658 depends on DISCONTIGMEM || SPARSEMEM
659 default y
661 config HAVE_ARCH_ALLOC_REMAP
662 bool
663 depends on NUMA
664 default y
666 config ARCH_FLATMEM_ENABLE
667 def_bool y
668 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
670 config ARCH_DISCONTIGMEM_ENABLE
671 def_bool y
672 depends on NUMA
674 config ARCH_DISCONTIGMEM_DEFAULT
675 def_bool y
676 depends on NUMA
678 config ARCH_SPARSEMEM_ENABLE
679 def_bool y
680 depends on (NUMA || (X86_PC && EXPERIMENTAL))
681 select SPARSEMEM_STATIC
683 config ARCH_SELECT_MEMORY_MODEL
684 def_bool y
685 depends on ARCH_SPARSEMEM_ENABLE
687 config ARCH_POPULATES_NODE_MAP
688 def_bool y
690 source "mm/Kconfig"
692 config HIGHPTE
693 bool "Allocate 3rd-level pagetables from highmem"
694 depends on HIGHMEM4G || HIGHMEM64G
695 help
696 The VM uses one page table entry for each page of physical memory.
697 For systems with a lot of RAM, this can be wasteful of precious
698 low memory. Setting this option will put user-space page table
699 entries in high memory.
701 config MATH_EMULATION
702 bool "Math emulation"
703 ---help---
704 Linux can emulate a math coprocessor (used for floating point
705 operations) if you don't have one. 486DX and Pentium processors have
706 a math coprocessor built in, 486SX and 386 do not, unless you added
707 a 487DX or 387, respectively. (The messages during boot time can
708 give you some hints here ["man dmesg"].) Everyone needs either a
709 coprocessor or this emulation.
711 If you don't have a math coprocessor, you need to say Y here; if you
712 say Y here even though you have a coprocessor, the coprocessor will
713 be used nevertheless. (This behavior can be changed with the kernel
714 command line option "no387", which comes handy if your coprocessor
715 is broken. Try "man bootparam" or see the documentation of your boot
716 loader (lilo or loadlin) about how to pass options to the kernel at
717 boot time.) This means that it is a good idea to say Y here if you
718 intend to use this kernel on different machines.
720 More information about the internals of the Linux math coprocessor
721 emulation can be found in <file:arch/x86/math-emu/README>.
723 If you are not sure, say Y; apart from resulting in a 66 KB bigger
724 kernel, it won't hurt.
726 config MTRR
727 bool "MTRR (Memory Type Range Register) support"
728 ---help---
729 On Intel P6 family processors (Pentium Pro, Pentium II and later)
730 the Memory Type Range Registers (MTRRs) may be used to control
731 processor access to memory ranges. This is most useful if you have
732 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
733 allows bus write transfers to be combined into a larger transfer
734 before bursting over the PCI/AGP bus. This can increase performance
735 of image write operations 2.5 times or more. Saying Y here creates a
736 /proc/mtrr file which may be used to manipulate your processor's
737 MTRRs. Typically the X server should use this.
739 This code has a reasonably generic interface so that similar
740 control registers on other processors can be easily supported
741 as well:
743 The Cyrix 6x86, 6x86MX and M II processors have Address Range
744 Registers (ARRs) which provide a similar functionality to MTRRs. For
745 these, the ARRs are used to emulate the MTRRs.
746 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
747 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
748 write-combining. All of these processors are supported by this code
749 and it makes sense to say Y here if you have one of them.
751 Saying Y here also fixes a problem with buggy SMP BIOSes which only
752 set the MTRRs for the boot CPU and not for the secondary CPUs. This
753 can lead to all sorts of problems, so it's good to say Y here.
755 You can safely say Y even if your machine doesn't have MTRRs, you'll
756 just add about 9 KB to your kernel.
758 See <file:Documentation/mtrr.txt> for more information.
760 config EFI
761 bool "Boot from EFI support"
762 depends on ACPI
763 default n
764 ---help---
765 This enables the kernel to boot on EFI platforms using
766 system configuration information passed to it from the firmware.
767 This also enables the kernel to use any EFI runtime services that are
768 available (such as the EFI variable services).
770 This option is only useful on systems that have EFI firmware
771 and will result in a kernel image that is ~8k larger. In addition,
772 you must use the latest ELILO loader available at
773 <http://elilo.sourceforge.net> in order to take advantage of
774 kernel initialization using EFI information (neither GRUB nor LILO know
775 anything about EFI). However, even with this option, the resultant
776 kernel should continue to boot on existing non-EFI platforms.
778 config IRQBALANCE
779 bool "Enable kernel irq balancing"
780 depends on SMP && X86_IO_APIC
781 default y
782 help
783 The default yes will allow the kernel to do irq load balancing.
784 Saying no will keep the kernel from doing irq load balancing.
786 # turning this on wastes a bunch of space.
787 # Summit needs it only when NUMA is on
788 config BOOT_IOREMAP
789 bool
790 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
791 default y
793 config SECCOMP
794 bool "Enable seccomp to safely compute untrusted bytecode"
795 depends on PROC_FS
796 default y
797 help
798 This kernel feature is useful for number crunching applications
799 that may need to compute untrusted bytecode during their
800 execution. By using pipes or other transports made available to
801 the process as file descriptors supporting the read/write
802 syscalls, it's possible to isolate those applications in
803 their own address space using seccomp. Once seccomp is
804 enabled via /proc/<pid>/seccomp, it cannot be disabled
805 and the task is only allowed to execute a few safe syscalls
806 defined by each seccomp mode.
808 If unsure, say Y. Only embedded should say N here.
810 source kernel/Kconfig.hz
812 config KEXEC
813 bool "kexec system call"
814 help
815 kexec is a system call that implements the ability to shutdown your
816 current kernel, and to start another kernel. It is like a reboot
817 but it is independent of the system firmware. And like a reboot
818 you can start any kernel with it, not just Linux.
820 The name comes from the similarity to the exec system call.
822 It is an ongoing process to be certain the hardware in a machine
823 is properly shutdown, so do not be surprised if this code does not
824 initially work for you. It may help to enable device hotplugging
825 support. As of this writing the exact hardware interface is
826 strongly in flux, so no good recommendation can be made.
828 config CRASH_DUMP
829 bool "kernel crash dumps (EXPERIMENTAL)"
830 depends on EXPERIMENTAL
831 depends on HIGHMEM
832 help
833 Generate crash dump after being started by kexec.
834 This should be normally only set in special crash dump kernels
835 which are loaded in the main kernel with kexec-tools into
836 a specially reserved region and then later executed after
837 a crash by kdump/kexec. The crash dump kernel must be compiled
838 to a memory address not used by the main kernel or BIOS using
839 PHYSICAL_START.
840 For more details see Documentation/kdump/kdump.txt
842 config PHYSICAL_START
843 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
844 default "0x1000000" if X86_NUMAQ
845 default "0x100000"
846 help
847 This gives the physical address where the kernel is loaded.
849 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
850 bzImage will decompress itself to above physical address and
851 run from there. Otherwise, bzImage will run from the address where
852 it has been loaded by the boot loader and will ignore above physical
853 address.
855 In normal kdump cases one does not have to set/change this option
856 as now bzImage can be compiled as a completely relocatable image
857 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
858 address. This option is mainly useful for the folks who don't want
859 to use a bzImage for capturing the crash dump and want to use a
860 vmlinux instead. vmlinux is not relocatable hence a kernel needs
861 to be specifically compiled to run from a specific memory area
862 (normally a reserved region) and this option comes handy.
864 So if you are using bzImage for capturing the crash dump, leave
865 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
866 Otherwise if you plan to use vmlinux for capturing the crash dump
867 change this value to start of the reserved region (Typically 16MB
868 0x1000000). In other words, it can be set based on the "X" value as
869 specified in the "crashkernel=YM@XM" command line boot parameter
870 passed to the panic-ed kernel. Typically this parameter is set as
871 crashkernel=64M@16M. Please take a look at
872 Documentation/kdump/kdump.txt for more details about crash dumps.
874 Usage of bzImage for capturing the crash dump is recommended as
875 one does not have to build two kernels. Same kernel can be used
876 as production kernel and capture kernel. Above option should have
877 gone away after relocatable bzImage support is introduced. But it
878 is present because there are users out there who continue to use
879 vmlinux for dump capture. This option should go away down the
880 line.
882 Don't change this unless you know what you are doing.
884 config RELOCATABLE
885 bool "Build a relocatable kernel(EXPERIMENTAL)"
886 depends on EXPERIMENTAL
887 help
888 This builds a kernel image that retains relocation information
889 so it can be loaded someplace besides the default 1MB.
890 The relocations tend to make the kernel binary about 10% larger,
891 but are discarded at runtime.
893 One use is for the kexec on panic case where the recovery kernel
894 must live at a different physical address than the primary
895 kernel.
897 config PHYSICAL_ALIGN
898 hex "Alignment value to which kernel should be aligned"
899 default "0x100000"
900 range 0x2000 0x400000
901 help
902 This value puts the alignment restrictions on physical address
903 where kernel is loaded and run from. Kernel is compiled for an
904 address which meets above alignment restriction.
906 If bootloader loads the kernel at a non-aligned address and
907 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
908 address aligned to above value and run from there.
910 If bootloader loads the kernel at a non-aligned address and
911 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
912 load address and decompress itself to the address it has been
913 compiled for and run from there. The address for which kernel is
914 compiled already meets above alignment restrictions. Hence the
915 end result is that kernel runs from a physical address meeting
916 above alignment restrictions.
918 Don't change this unless you know what you are doing.
920 config HOTPLUG_CPU
921 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
922 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
923 ---help---
924 Say Y here to experiment with turning CPUs off and on, and to
925 enable suspend on SMP systems. CPUs can be controlled through
926 /sys/devices/system/cpu.
928 config COMPAT_VDSO
929 bool "Compat VDSO support"
930 default y
931 help
932 Map the VDSO to the predictable old-style address too.
933 ---help---
934 Say N here if you are running a sufficiently recent glibc
935 version (2.3.3 or later), to remove the high-mapped
936 VDSO mapping and to exclusively use the randomized VDSO.
938 If unsure, say Y.
940 endmenu
942 config ARCH_ENABLE_MEMORY_HOTPLUG
943 def_bool y
944 depends on HIGHMEM
946 menu "Power management options (ACPI, APM)"
947 depends on !X86_VOYAGER
949 source kernel/power/Kconfig
951 source "drivers/acpi/Kconfig"
953 menuconfig APM
954 tristate "APM (Advanced Power Management) BIOS support"
955 depends on PM_SLEEP && !X86_VISWS
956 ---help---
957 APM is a BIOS specification for saving power using several different
958 techniques. This is mostly useful for battery powered laptops with
959 APM compliant BIOSes. If you say Y here, the system time will be
960 reset after a RESUME operation, the /proc/apm device will provide
961 battery status information, and user-space programs will receive
962 notification of APM "events" (e.g. battery status change).
964 If you select "Y" here, you can disable actual use of the APM
965 BIOS by passing the "apm=off" option to the kernel at boot time.
967 Note that the APM support is almost completely disabled for
968 machines with more than one CPU.
970 In order to use APM, you will need supporting software. For location
971 and more information, read <file:Documentation/pm.txt> and the
972 Battery Powered Linux mini-HOWTO, available from
973 <http://www.tldp.org/docs.html#howto>.
975 This driver does not spin down disk drives (see the hdparm(8)
976 manpage ("man 8 hdparm") for that), and it doesn't turn off
977 VESA-compliant "green" monitors.
979 This driver does not support the TI 4000M TravelMate and the ACER
980 486/DX4/75 because they don't have compliant BIOSes. Many "green"
981 desktop machines also don't have compliant BIOSes, and this driver
982 may cause those machines to panic during the boot phase.
984 Generally, if you don't have a battery in your machine, there isn't
985 much point in using this driver and you should say N. If you get
986 random kernel OOPSes or reboots that don't seem to be related to
987 anything, try disabling/enabling this option (or disabling/enabling
988 APM in your BIOS).
990 Some other things you should try when experiencing seemingly random,
991 "weird" problems:
993 1) make sure that you have enough swap space and that it is
994 enabled.
995 2) pass the "no-hlt" option to the kernel
996 3) switch on floating point emulation in the kernel and pass
997 the "no387" option to the kernel
998 4) pass the "floppy=nodma" option to the kernel
999 5) pass the "mem=4M" option to the kernel (thereby disabling
1000 all but the first 4 MB of RAM)
1001 6) make sure that the CPU is not over clocked.
1002 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1003 8) disable the cache from your BIOS settings
1004 9) install a fan for the video card or exchange video RAM
1005 10) install a better fan for the CPU
1006 11) exchange RAM chips
1007 12) exchange the motherboard.
1009 To compile this driver as a module, choose M here: the
1010 module will be called apm.
1012 if APM
1014 config APM_IGNORE_USER_SUSPEND
1015 bool "Ignore USER SUSPEND"
1016 help
1017 This option will ignore USER SUSPEND requests. On machines with a
1018 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1019 series notebooks, it is necessary to say Y because of a BIOS bug.
1021 config APM_DO_ENABLE
1022 bool "Enable PM at boot time"
1023 ---help---
1024 Enable APM features at boot time. From page 36 of the APM BIOS
1025 specification: "When disabled, the APM BIOS does not automatically
1026 power manage devices, enter the Standby State, enter the Suspend
1027 State, or take power saving steps in response to CPU Idle calls."
1028 This driver will make CPU Idle calls when Linux is idle (unless this
1029 feature is turned off -- see "Do CPU IDLE calls", below). This
1030 should always save battery power, but more complicated APM features
1031 will be dependent on your BIOS implementation. You may need to turn
1032 this option off if your computer hangs at boot time when using APM
1033 support, or if it beeps continuously instead of suspending. Turn
1034 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1035 T400CDT. This is off by default since most machines do fine without
1036 this feature.
1038 config APM_CPU_IDLE
1039 bool "Make CPU Idle calls when idle"
1040 help
1041 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1042 On some machines, this can activate improved power savings, such as
1043 a slowed CPU clock rate, when the machine is idle. These idle calls
1044 are made after the idle loop has run for some length of time (e.g.,
1045 333 mS). On some machines, this will cause a hang at boot time or
1046 whenever the CPU becomes idle. (On machines with more than one CPU,
1047 this option does nothing.)
1049 config APM_DISPLAY_BLANK
1050 bool "Enable console blanking using APM"
1051 help
1052 Enable console blanking using the APM. Some laptops can use this to
1053 turn off the LCD backlight when the screen blanker of the Linux
1054 virtual console blanks the screen. Note that this is only used by
1055 the virtual console screen blanker, and won't turn off the backlight
1056 when using the X Window system. This also doesn't have anything to
1057 do with your VESA-compliant power-saving monitor. Further, this
1058 option doesn't work for all laptops -- it might not turn off your
1059 backlight at all, or it might print a lot of errors to the console,
1060 especially if you are using gpm.
1062 config APM_ALLOW_INTS
1063 bool "Allow interrupts during APM BIOS calls"
1064 help
1065 Normally we disable external interrupts while we are making calls to
1066 the APM BIOS as a measure to lessen the effects of a badly behaving
1067 BIOS implementation. The BIOS should reenable interrupts if it
1068 needs to. Unfortunately, some BIOSes do not -- especially those in
1069 many of the newer IBM Thinkpads. If you experience hangs when you
1070 suspend, try setting this to Y. Otherwise, say N.
1072 config APM_REAL_MODE_POWER_OFF
1073 bool "Use real mode APM BIOS call to power off"
1074 help
1075 Use real mode APM BIOS calls to switch off the computer. This is
1076 a work-around for a number of buggy BIOSes. Switch this option on if
1077 your computer crashes instead of powering off properly.
1079 endif # APM
1081 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1083 endmenu
1085 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1087 config PCI
1088 bool "PCI support" if !X86_VISWS
1089 depends on !X86_VOYAGER
1090 default y if X86_VISWS
1091 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1092 help
1093 Find out whether you have a PCI motherboard. PCI is the name of a
1094 bus system, i.e. the way the CPU talks to the other stuff inside
1095 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1096 VESA. If you have PCI, say Y, otherwise N.
1098 The PCI-HOWTO, available from
1099 <http://www.tldp.org/docs.html#howto>, contains valuable
1100 information about which PCI hardware does work under Linux and which
1101 doesn't.
1103 choice
1104 prompt "PCI access mode"
1105 depends on PCI && !X86_VISWS
1106 default PCI_GOANY
1107 ---help---
1108 On PCI systems, the BIOS can be used to detect the PCI devices and
1109 determine their configuration. However, some old PCI motherboards
1110 have BIOS bugs and may crash if this is done. Also, some embedded
1111 PCI-based systems don't have any BIOS at all. Linux can also try to
1112 detect the PCI hardware directly without using the BIOS.
1114 With this option, you can specify how Linux should detect the
1115 PCI devices. If you choose "BIOS", the BIOS will be used,
1116 if you choose "Direct", the BIOS won't be used, and if you
1117 choose "MMConfig", then PCI Express MMCONFIG will be used.
1118 If you choose "Any", the kernel will try MMCONFIG, then the
1119 direct access method and falls back to the BIOS if that doesn't
1120 work. If unsure, go with the default, which is "Any".
1122 config PCI_GOBIOS
1123 bool "BIOS"
1125 config PCI_GOMMCONFIG
1126 bool "MMConfig"
1128 config PCI_GODIRECT
1129 bool "Direct"
1131 config PCI_GOANY
1132 bool "Any"
1134 endchoice
1136 config PCI_BIOS
1137 bool
1138 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1139 default y
1141 config PCI_DIRECT
1142 bool
1143 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1144 default y
1146 config PCI_MMCONFIG
1147 bool
1148 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1149 default y
1151 config PCI_DOMAINS
1152 bool
1153 depends on PCI
1154 default y
1156 source "drivers/pci/pcie/Kconfig"
1158 source "drivers/pci/Kconfig"
1160 config ISA_DMA_API
1161 bool
1162 default y
1164 config ISA
1165 bool "ISA support"
1166 depends on !(X86_VOYAGER || X86_VISWS)
1167 help
1168 Find out whether you have ISA slots on your motherboard. ISA is the
1169 name of a bus system, i.e. the way the CPU talks to the other stuff
1170 inside your box. Other bus systems are PCI, EISA, MicroChannel
1171 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1172 newer boards don't support it. If you have ISA, say Y, otherwise N.
1174 config EISA
1175 bool "EISA support"
1176 depends on ISA
1177 ---help---
1178 The Extended Industry Standard Architecture (EISA) bus was
1179 developed as an open alternative to the IBM MicroChannel bus.
1181 The EISA bus provided some of the features of the IBM MicroChannel
1182 bus while maintaining backward compatibility with cards made for
1183 the older ISA bus. The EISA bus saw limited use between 1988 and
1184 1995 when it was made obsolete by the PCI bus.
1186 Say Y here if you are building a kernel for an EISA-based machine.
1188 Otherwise, say N.
1190 source "drivers/eisa/Kconfig"
1192 config MCA
1193 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1194 default y if X86_VOYAGER
1195 help
1196 MicroChannel Architecture is found in some IBM PS/2 machines and
1197 laptops. It is a bus system similar to PCI or ISA. See
1198 <file:Documentation/mca.txt> (and especially the web page given
1199 there) before attempting to build an MCA bus kernel.
1201 source "drivers/mca/Kconfig"
1203 config SCx200
1204 tristate "NatSemi SCx200 support"
1205 depends on !X86_VOYAGER
1206 help
1207 This provides basic support for National Semiconductor's
1208 (now AMD's) Geode processors. The driver probes for the
1209 PCI-IDs of several on-chip devices, so its a good dependency
1210 for other scx200_* drivers.
1212 If compiled as a module, the driver is named scx200.
1214 config SCx200HR_TIMER
1215 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1216 depends on SCx200 && GENERIC_TIME
1217 default y
1218 help
1219 This driver provides a clocksource built upon the on-chip
1220 27MHz high-resolution timer. Its also a workaround for
1221 NSC Geode SC-1100's buggy TSC, which loses time when the
1222 processor goes idle (as is done by the scheduler). The
1223 other workaround is idle=poll boot option.
1225 config GEODE_MFGPT_TIMER
1226 bool "Geode Multi-Function General Purpose Timer (MFGPT) events"
1227 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1228 default y
1229 help
1230 This driver provides a clock event source based on the MFGPT
1231 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1232 MFGPTs have a better resolution and max interval than the
1233 generic PIT, and are suitable for use as high-res timers.
1235 config K8_NB
1236 def_bool y
1237 depends on AGP_AMD64
1239 source "drivers/pcmcia/Kconfig"
1241 source "drivers/pci/hotplug/Kconfig"
1243 endmenu
1245 menu "Executable file formats"
1247 source "fs/Kconfig.binfmt"
1249 endmenu
1251 source "net/Kconfig"
1253 source "drivers/Kconfig"
1255 source "fs/Kconfig"
1257 menuconfig INSTRUMENTATION
1258 bool "Instrumentation Support"
1259 default y
1260 ---help---
1261 Say Y here to get to see options related to performance measurement,
1262 debugging, and testing. This option alone does not add any kernel code.
1264 If you say N, all options in this submenu will be skipped and disabled.
1266 if INSTRUMENTATION
1268 source "arch/x86/oprofile/Kconfig"
1270 config KPROBES
1271 bool "Kprobes"
1272 depends on KALLSYMS && MODULES
1273 help
1274 Kprobes allows you to trap at almost any kernel address and
1275 execute a callback function. register_kprobe() establishes
1276 a probepoint and specifies the callback. Kprobes is useful
1277 for kernel debugging, non-intrusive instrumentation and testing.
1278 If in doubt, say "N".
1280 endif # INSTRUMENTATION
1282 source "arch/i386/Kconfig.debug"
1284 source "security/Kconfig"
1286 source "crypto/Kconfig"
1288 source "lib/Kconfig"
1290 #
1291 # Use the generic interrupt handling code in kernel/irq/:
1292 #
1293 config GENERIC_HARDIRQS
1294 bool
1295 default y
1297 config GENERIC_IRQ_PROBE
1298 bool
1299 default y
1301 config GENERIC_PENDING_IRQ
1302 bool
1303 depends on GENERIC_HARDIRQS && SMP
1304 default y
1306 config X86_SMP
1307 bool
1308 depends on SMP && !X86_VOYAGER
1309 default y
1311 config X86_HT
1312 bool
1313 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1314 default y
1316 config X86_BIOS_REBOOT
1317 bool
1318 depends on !(X86_VISWS || X86_VOYAGER)
1319 default y
1321 config X86_TRAMPOLINE
1322 bool
1323 depends on X86_SMP || (X86_VOYAGER && SMP)
1324 default y
1326 config KTIME_SCALAR
1327 bool
1328 default y