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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 PARAVIRT
218 bool "Paravirtualization support (EXPERIMENTAL)"
219 depends on EXPERIMENTAL
220 depends on !(X86_VISWS || X86_VOYAGER)
221 help
222 Paravirtualization is a way of running multiple instances of
223 Linux on the same machine, under a hypervisor. This option
224 changes the kernel so it can modify itself when it is run
225 under a hypervisor, improving performance significantly.
226 However, when run without a hypervisor the kernel is
227 theoretically slower. If in doubt, say N.
229 source "arch/i386/xen/Kconfig"
231 config VMI
232 bool "VMI Paravirt-ops support"
233 depends on PARAVIRT
234 help
235 VMI provides a paravirtualized interface to the VMware ESX server
236 (it could be used by other hypervisors in theory too, but is not
237 at the moment), by linking the kernel to a GPL-ed ROM module
238 provided by the hypervisor.
240 config ACPI_SRAT
241 bool
242 default y
243 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
244 select ACPI_NUMA
246 config HAVE_ARCH_PARSE_SRAT
247 bool
248 default y
249 depends on ACPI_SRAT
251 config X86_SUMMIT_NUMA
252 bool
253 default y
254 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
256 config X86_CYCLONE_TIMER
257 bool
258 default y
259 depends on X86_SUMMIT || X86_GENERICARCH
261 config ES7000_CLUSTERED_APIC
262 bool
263 default y
264 depends on SMP && X86_ES7000 && MPENTIUMIII
266 source "arch/i386/Kconfig.cpu"
268 config HPET_TIMER
269 bool "HPET Timer Support"
270 help
271 This enables the use of the HPET for the kernel's internal timer.
272 HPET is the next generation timer replacing legacy 8254s.
273 You can safely choose Y here. However, HPET will only be
274 activated if the platform and the BIOS support this feature.
275 Otherwise the 8254 will be used for timing services.
277 Choose N to continue using the legacy 8254 timer.
279 config HPET_EMULATE_RTC
280 bool
281 depends on HPET_TIMER && RTC=y
282 default y
284 config NR_CPUS
285 int "Maximum number of CPUs (2-255)"
286 range 2 255
287 depends on SMP
288 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
289 default "8"
290 help
291 This allows you to specify the maximum number of CPUs which this
292 kernel will support. The maximum supported value is 255 and the
293 minimum value which makes sense is 2.
295 This is purely to save memory - each supported CPU adds
296 approximately eight kilobytes to the kernel image.
298 config SCHED_SMT
299 bool "SMT (Hyperthreading) scheduler support"
300 depends on X86_HT
301 help
302 SMT scheduler support improves the CPU scheduler's decision making
303 when dealing with Intel Pentium 4 chips with HyperThreading at a
304 cost of slightly increased overhead in some places. If unsure say
305 N here.
307 config SCHED_MC
308 bool "Multi-core scheduler support"
309 depends on X86_HT
310 default y
311 help
312 Multi-core scheduler support improves the CPU scheduler's decision
313 making when dealing with multi-core CPU chips at a cost of slightly
314 increased overhead in some places. If unsure say N here.
316 source "kernel/Kconfig.preempt"
318 config X86_UP_APIC
319 bool "Local APIC support on uniprocessors"
320 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
321 help
322 A local APIC (Advanced Programmable Interrupt Controller) is an
323 integrated interrupt controller in the CPU. If you have a single-CPU
324 system which has a processor with a local APIC, you can say Y here to
325 enable and use it. If you say Y here even though your machine doesn't
326 have a local APIC, then the kernel will still run with no slowdown at
327 all. The local APIC supports CPU-generated self-interrupts (timer,
328 performance counters), and the NMI watchdog which detects hard
329 lockups.
331 config X86_UP_IOAPIC
332 bool "IO-APIC support on uniprocessors"
333 depends on X86_UP_APIC
334 help
335 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
336 SMP-capable replacement for PC-style interrupt controllers. Most
337 SMP systems and many recent uniprocessor systems have one.
339 If you have a single-CPU system with an IO-APIC, you can say Y here
340 to use it. If you say Y here even though your machine doesn't have
341 an IO-APIC, then the kernel will still run with no slowdown at all.
343 config X86_LOCAL_APIC
344 bool
345 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
346 default y
348 config X86_IO_APIC
349 bool
350 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
351 default y
353 config X86_VISWS_APIC
354 bool
355 depends on X86_VISWS
356 default y
358 config X86_MCE
359 bool "Machine Check Exception"
360 depends on !X86_VOYAGER
361 ---help---
362 Machine Check Exception support allows the processor to notify the
363 kernel if it detects a problem (e.g. overheating, component failure).
364 The action the kernel takes depends on the severity of the problem,
365 ranging from a warning message on the console, to halting the machine.
366 Your processor must be a Pentium or newer to support this - check the
367 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
368 have a design flaw which leads to false MCE events - hence MCE is
369 disabled on all P5 processors, unless explicitly enabled with "mce"
370 as a boot argument. Similarly, if MCE is built in and creates a
371 problem on some new non-standard machine, you can boot with "nomce"
372 to disable it. MCE support simply ignores non-MCE processors like
373 the 386 and 486, so nearly everyone can say Y here.
375 config X86_MCE_NONFATAL
376 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
377 depends on X86_MCE
378 help
379 Enabling this feature starts a timer that triggers every 5 seconds which
380 will look at the machine check registers to see if anything happened.
381 Non-fatal problems automatically get corrected (but still logged).
382 Disable this if you don't want to see these messages.
383 Seeing the messages this option prints out may be indicative of dying hardware,
384 or out-of-spec (ie, overclocked) hardware.
385 This option only does something on certain CPUs.
386 (AMD Athlon/Duron and Intel Pentium 4)
388 config X86_MCE_P4THERMAL
389 bool "check for P4 thermal throttling interrupt."
390 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
391 help
392 Enabling this feature will cause a message to be printed when the P4
393 enters thermal throttling.
395 config VM86
396 default y
397 bool "Enable VM86 support" if EMBEDDED
398 help
399 This option is required by programs like DOSEMU to run 16-bit legacy
400 code on X86 processors. It also may be needed by software like
401 XFree86 to initialize some video cards via BIOS. Disabling this
402 option saves about 6k.
404 config TOSHIBA
405 tristate "Toshiba Laptop support"
406 ---help---
407 This adds a driver to safely access the System Management Mode of
408 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
409 not work on models with a Phoenix BIOS. The System Management Mode
410 is used to set the BIOS and power saving options on Toshiba portables.
412 For information on utilities to make use of this driver see the
413 Toshiba Linux utilities web site at:
414 <http://www.buzzard.org.uk/toshiba/>.
416 Say Y if you intend to run this kernel on a Toshiba portable.
417 Say N otherwise.
419 config I8K
420 tristate "Dell laptop support"
421 ---help---
422 This adds a driver to safely access the System Management Mode
423 of the CPU on the Dell Inspiron 8000. The System Management Mode
424 is used to read cpu temperature and cooling fan status and to
425 control the fans on the I8K portables.
427 This driver has been tested only on the Inspiron 8000 but it may
428 also work with other Dell laptops. You can force loading on other
429 models by passing the parameter `force=1' to the module. Use at
430 your own risk.
432 For information on utilities to make use of this driver see the
433 I8K Linux utilities web site at:
434 <http://people.debian.org/~dz/i8k/>
436 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
437 Say N otherwise.
439 config X86_REBOOTFIXUPS
440 bool "Enable X86 board specific fixups for reboot"
441 depends on X86
442 default n
443 ---help---
444 This enables chipset and/or board specific fixups to be done
445 in order to get reboot to work correctly. This is only needed on
446 some combinations of hardware and BIOS. The symptom, for which
447 this config is intended, is when reboot ends with a stalled/hung
448 system.
450 Currently, the only fixup is for the Geode machines using
451 CS5530A and CS5536 chipsets.
453 Say Y if you want to enable the fixup. Currently, it's safe to
454 enable this option even if you don't need it.
455 Say N otherwise.
457 config MICROCODE
458 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
459 select FW_LOADER
460 ---help---
461 If you say Y here, you will be able to update the microcode on
462 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
463 Pentium III, Pentium 4, Xeon etc. You will obviously need the
464 actual microcode binary data itself which is not shipped with the
465 Linux kernel.
467 For latest news and information on obtaining all the required
468 ingredients for this driver, check:
469 <http://www.urbanmyth.org/microcode/>.
471 To compile this driver as a module, choose M here: the
472 module will be called microcode.
474 config MICROCODE_OLD_INTERFACE
475 bool
476 depends on MICROCODE
477 default y
479 config X86_MSR
480 tristate "/dev/cpu/*/msr - Model-specific register support"
481 help
482 This device gives privileged processes access to the x86
483 Model-Specific Registers (MSRs). It is a character device with
484 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
485 MSR accesses are directed to a specific CPU on multi-processor
486 systems.
488 config X86_CPUID
489 tristate "/dev/cpu/*/cpuid - CPU information support"
490 help
491 This device gives processes access to the x86 CPUID instruction to
492 be executed on a specific processor. It is a character device
493 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
494 /dev/cpu/31/cpuid.
496 source "drivers/firmware/Kconfig"
498 choice
499 prompt "High Memory Support"
500 default HIGHMEM4G if !X86_NUMAQ
501 default HIGHMEM64G if X86_NUMAQ
503 config NOHIGHMEM
504 bool "off"
505 depends on !X86_NUMAQ
506 ---help---
507 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
508 However, the address space of 32-bit x86 processors is only 4
509 Gigabytes large. That means that, if you have a large amount of
510 physical memory, not all of it can be "permanently mapped" by the
511 kernel. The physical memory that's not permanently mapped is called
512 "high memory".
514 If you are compiling a kernel which will never run on a machine with
515 more than 1 Gigabyte total physical RAM, answer "off" here (default
516 choice and suitable for most users). This will result in a "3GB/1GB"
517 split: 3GB are mapped so that each process sees a 3GB virtual memory
518 space and the remaining part of the 4GB virtual memory space is used
519 by the kernel to permanently map as much physical memory as
520 possible.
522 If the machine has between 1 and 4 Gigabytes physical RAM, then
523 answer "4GB" here.
525 If more than 4 Gigabytes is used then answer "64GB" here. This
526 selection turns Intel PAE (Physical Address Extension) mode on.
527 PAE implements 3-level paging on IA32 processors. PAE is fully
528 supported by Linux, PAE mode is implemented on all recent Intel
529 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
530 then the kernel will not boot on CPUs that don't support PAE!
532 The actual amount of total physical memory will either be
533 auto detected or can be forced by using a kernel command line option
534 such as "mem=256M". (Try "man bootparam" or see the documentation of
535 your boot loader (lilo or loadlin) about how to pass options to the
536 kernel at boot time.)
538 If unsure, say "off".
540 config HIGHMEM4G
541 bool "4GB"
542 depends on !X86_NUMAQ
543 help
544 Select this if you have a 32-bit processor and between 1 and 4
545 gigabytes of physical RAM.
547 config HIGHMEM64G
548 bool "64GB"
549 depends on !M386 && !M486
550 select X86_PAE
551 help
552 Select this if you have a 32-bit processor and more than 4
553 gigabytes of physical RAM.
555 endchoice
557 choice
558 depends on EXPERIMENTAL
559 prompt "Memory split" if EMBEDDED
560 default VMSPLIT_3G
561 help
562 Select the desired split between kernel and user memory.
564 If the address range available to the kernel is less than the
565 physical memory installed, the remaining memory will be available
566 as "high memory". Accessing high memory is a little more costly
567 than low memory, as it needs to be mapped into the kernel first.
568 Note that increasing the kernel address space limits the range
569 available to user programs, making the address space there
570 tighter. Selecting anything other than the default 3G/1G split
571 will also likely make your kernel incompatible with binary-only
572 kernel modules.
574 If you are not absolutely sure what you are doing, leave this
575 option alone!
577 config VMSPLIT_3G
578 bool "3G/1G user/kernel split"
579 config VMSPLIT_3G_OPT
580 depends on !X86_PAE
581 bool "3G/1G user/kernel split (for full 1G low memory)"
582 config VMSPLIT_2G
583 bool "2G/2G user/kernel split"
584 config VMSPLIT_2G_OPT
585 depends on !X86_PAE
586 bool "2G/2G user/kernel split (for full 2G low memory)"
587 config VMSPLIT_1G
588 bool "1G/3G user/kernel split"
589 endchoice
591 config PAGE_OFFSET
592 hex
593 default 0xB0000000 if VMSPLIT_3G_OPT
594 default 0x80000000 if VMSPLIT_2G
595 default 0x78000000 if VMSPLIT_2G_OPT
596 default 0x40000000 if VMSPLIT_1G
597 default 0xC0000000
599 config HIGHMEM
600 bool
601 depends on HIGHMEM64G || HIGHMEM4G
602 default y
604 config X86_PAE
605 bool "PAE (Physical Address Extension) Support"
606 default n
607 depends on !HIGHMEM4G
608 select RESOURCES_64BIT
609 help
610 PAE is required for NX support, and furthermore enables
611 larger swapspace support for non-overcommit purposes. It
612 has the cost of more pagetable lookup overhead, and also
613 consumes more pagetable space per process.
615 # Common NUMA Features
616 config NUMA
617 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
618 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL
619 default n if X86_PC
620 default y if (X86_NUMAQ || X86_SUMMIT)
621 help
622 NUMA support for i386. This is currently high experimental
623 and should be only used for kernel development. It might also
624 cause boot failures.
626 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
627 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
629 config NODES_SHIFT
630 int
631 default "4" if X86_NUMAQ
632 default "3"
633 depends on NEED_MULTIPLE_NODES
635 config HAVE_ARCH_BOOTMEM_NODE
636 bool
637 depends on NUMA
638 default y
640 config ARCH_HAVE_MEMORY_PRESENT
641 bool
642 depends on DISCONTIGMEM
643 default y
645 config NEED_NODE_MEMMAP_SIZE
646 bool
647 depends on DISCONTIGMEM || SPARSEMEM
648 default y
650 config HAVE_ARCH_ALLOC_REMAP
651 bool
652 depends on NUMA
653 default y
655 config ARCH_FLATMEM_ENABLE
656 def_bool y
657 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
659 config ARCH_DISCONTIGMEM_ENABLE
660 def_bool y
661 depends on NUMA
663 config ARCH_DISCONTIGMEM_DEFAULT
664 def_bool y
665 depends on NUMA
667 config ARCH_SPARSEMEM_ENABLE
668 def_bool y
669 depends on (NUMA || (X86_PC && EXPERIMENTAL))
670 select SPARSEMEM_STATIC
672 config ARCH_SELECT_MEMORY_MODEL
673 def_bool y
674 depends on ARCH_SPARSEMEM_ENABLE
676 config ARCH_POPULATES_NODE_MAP
677 def_bool y
679 source "mm/Kconfig"
681 config HIGHPTE
682 bool "Allocate 3rd-level pagetables from highmem"
683 depends on HIGHMEM4G || HIGHMEM64G
684 help
685 The VM uses one page table entry for each page of physical memory.
686 For systems with a lot of RAM, this can be wasteful of precious
687 low memory. Setting this option will put user-space page table
688 entries in high memory.
690 config MATH_EMULATION
691 bool "Math emulation"
692 ---help---
693 Linux can emulate a math coprocessor (used for floating point
694 operations) if you don't have one. 486DX and Pentium processors have
695 a math coprocessor built in, 486SX and 386 do not, unless you added
696 a 487DX or 387, respectively. (The messages during boot time can
697 give you some hints here ["man dmesg"].) Everyone needs either a
698 coprocessor or this emulation.
700 If you don't have a math coprocessor, you need to say Y here; if you
701 say Y here even though you have a coprocessor, the coprocessor will
702 be used nevertheless. (This behavior can be changed with the kernel
703 command line option "no387", which comes handy if your coprocessor
704 is broken. Try "man bootparam" or see the documentation of your boot
705 loader (lilo or loadlin) about how to pass options to the kernel at
706 boot time.) This means that it is a good idea to say Y here if you
707 intend to use this kernel on different machines.
709 More information about the internals of the Linux math coprocessor
710 emulation can be found in <file:arch/i386/math-emu/README>.
712 If you are not sure, say Y; apart from resulting in a 66 KB bigger
713 kernel, it won't hurt.
715 config MTRR
716 bool "MTRR (Memory Type Range Register) support"
717 ---help---
718 On Intel P6 family processors (Pentium Pro, Pentium II and later)
719 the Memory Type Range Registers (MTRRs) may be used to control
720 processor access to memory ranges. This is most useful if you have
721 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
722 allows bus write transfers to be combined into a larger transfer
723 before bursting over the PCI/AGP bus. This can increase performance
724 of image write operations 2.5 times or more. Saying Y here creates a
725 /proc/mtrr file which may be used to manipulate your processor's
726 MTRRs. Typically the X server should use this.
728 This code has a reasonably generic interface so that similar
729 control registers on other processors can be easily supported
730 as well:
732 The Cyrix 6x86, 6x86MX and M II processors have Address Range
733 Registers (ARRs) which provide a similar functionality to MTRRs. For
734 these, the ARRs are used to emulate the MTRRs.
735 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
736 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
737 write-combining. All of these processors are supported by this code
738 and it makes sense to say Y here if you have one of them.
740 Saying Y here also fixes a problem with buggy SMP BIOSes which only
741 set the MTRRs for the boot CPU and not for the secondary CPUs. This
742 can lead to all sorts of problems, so it's good to say Y here.
744 You can safely say Y even if your machine doesn't have MTRRs, you'll
745 just add about 9 KB to your kernel.
747 See <file:Documentation/mtrr.txt> for more information.
749 config EFI
750 bool "Boot from EFI support"
751 depends on ACPI
752 default n
753 ---help---
754 This enables the kernel to boot on EFI platforms using
755 system configuration information passed to it from the firmware.
756 This also enables the kernel to use any EFI runtime services that are
757 available (such as the EFI variable services).
759 This option is only useful on systems that have EFI firmware
760 and will result in a kernel image that is ~8k larger. In addition,
761 you must use the latest ELILO loader available at
762 <http://elilo.sourceforge.net> in order to take advantage of
763 kernel initialization using EFI information (neither GRUB nor LILO know
764 anything about EFI). However, even with this option, the resultant
765 kernel should continue to boot on existing non-EFI platforms.
767 config IRQBALANCE
768 bool "Enable kernel irq balancing"
769 depends on SMP && X86_IO_APIC
770 default y
771 help
772 The default yes will allow the kernel to do irq load balancing.
773 Saying no will keep the kernel from doing irq load balancing.
775 # turning this on wastes a bunch of space.
776 # Summit needs it only when NUMA is on
777 config BOOT_IOREMAP
778 bool
779 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
780 default y
782 config SECCOMP
783 bool "Enable seccomp to safely compute untrusted bytecode"
784 depends on PROC_FS
785 default y
786 help
787 This kernel feature is useful for number crunching applications
788 that may need to compute untrusted bytecode during their
789 execution. By using pipes or other transports made available to
790 the process as file descriptors supporting the read/write
791 syscalls, it's possible to isolate those applications in
792 their own address space using seccomp. Once seccomp is
793 enabled via /proc/<pid>/seccomp, it cannot be disabled
794 and the task is only allowed to execute a few safe syscalls
795 defined by each seccomp mode.
797 If unsure, say Y. Only embedded should say N here.
799 source kernel/Kconfig.hz
801 config KEXEC
802 bool "kexec system call"
803 help
804 kexec is a system call that implements the ability to shutdown your
805 current kernel, and to start another kernel. It is like a reboot
806 but it is independent of the system firmware. And like a reboot
807 you can start any kernel with it, not just Linux.
809 The name comes from the similarity to the exec system call.
811 It is an ongoing process to be certain the hardware in a machine
812 is properly shutdown, so do not be surprised if this code does not
813 initially work for you. It may help to enable device hotplugging
814 support. As of this writing the exact hardware interface is
815 strongly in flux, so no good recommendation can be made.
817 config CRASH_DUMP
818 bool "kernel crash dumps (EXPERIMENTAL)"
819 depends on EXPERIMENTAL
820 depends on HIGHMEM
821 help
822 Generate crash dump after being started by kexec.
823 This should be normally only set in special crash dump kernels
824 which are loaded in the main kernel with kexec-tools into
825 a specially reserved region and then later executed after
826 a crash by kdump/kexec. The crash dump kernel must be compiled
827 to a memory address not used by the main kernel or BIOS using
828 PHYSICAL_START.
829 For more details see Documentation/kdump/kdump.txt
831 config PHYSICAL_START
832 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
833 default "0x1000000" if X86_NUMAQ
834 default "0x100000"
835 help
836 This gives the physical address where the kernel is loaded.
838 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
839 bzImage will decompress itself to above physical address and
840 run from there. Otherwise, bzImage will run from the address where
841 it has been loaded by the boot loader and will ignore above physical
842 address.
844 In normal kdump cases one does not have to set/change this option
845 as now bzImage can be compiled as a completely relocatable image
846 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
847 address. This option is mainly useful for the folks who don't want
848 to use a bzImage for capturing the crash dump and want to use a
849 vmlinux instead. vmlinux is not relocatable hence a kernel needs
850 to be specifically compiled to run from a specific memory area
851 (normally a reserved region) and this option comes handy.
853 So if you are using bzImage for capturing the crash dump, leave
854 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
855 Otherwise if you plan to use vmlinux for capturing the crash dump
856 change this value to start of the reserved region (Typically 16MB
857 0x1000000). In other words, it can be set based on the "X" value as
858 specified in the "crashkernel=YM@XM" command line boot parameter
859 passed to the panic-ed kernel. Typically this parameter is set as
860 crashkernel=64M@16M. Please take a look at
861 Documentation/kdump/kdump.txt for more details about crash dumps.
863 Usage of bzImage for capturing the crash dump is recommended as
864 one does not have to build two kernels. Same kernel can be used
865 as production kernel and capture kernel. Above option should have
866 gone away after relocatable bzImage support is introduced. But it
867 is present because there are users out there who continue to use
868 vmlinux for dump capture. This option should go away down the
869 line.
871 Don't change this unless you know what you are doing.
873 config RELOCATABLE
874 bool "Build a relocatable kernel(EXPERIMENTAL)"
875 depends on EXPERIMENTAL
876 help
877 This builds a kernel image that retains relocation information
878 so it can be loaded someplace besides the default 1MB.
879 The relocations tend to make the kernel binary about 10% larger,
880 but are discarded at runtime.
882 One use is for the kexec on panic case where the recovery kernel
883 must live at a different physical address than the primary
884 kernel.
886 config PHYSICAL_ALIGN
887 hex "Alignment value to which kernel should be aligned"
888 default "0x100000"
889 range 0x2000 0x400000
890 help
891 This value puts the alignment restrictions on physical address
892 where kernel is loaded and run from. Kernel is compiled for an
893 address which meets above alignment restriction.
895 If bootloader loads the kernel at a non-aligned address and
896 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
897 address aligned to above value and run from there.
899 If bootloader loads the kernel at a non-aligned address and
900 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
901 load address and decompress itself to the address it has been
902 compiled for and run from there. The address for which kernel is
903 compiled already meets above alignment restrictions. Hence the
904 end result is that kernel runs from a physical address meeting
905 above alignment restrictions.
907 Don't change this unless you know what you are doing.
909 config HOTPLUG_CPU
910 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
911 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
912 ---help---
913 Say Y here to experiment with turning CPUs off and on, and to
914 enable suspend on SMP systems. CPUs can be controlled through
915 /sys/devices/system/cpu.
917 config COMPAT_VDSO
918 bool "Compat VDSO support"
919 default y
920 help
921 Map the VDSO to the predictable old-style address too.
922 ---help---
923 Say N here if you are running a sufficiently recent glibc
924 version (2.3.3 or later), to remove the high-mapped
925 VDSO mapping and to exclusively use the randomized VDSO.
927 If unsure, say Y.
929 endmenu
931 config ARCH_ENABLE_MEMORY_HOTPLUG
932 def_bool y
933 depends on HIGHMEM
935 menu "Power management options (ACPI, APM)"
936 depends on !X86_VOYAGER
938 source kernel/power/Kconfig
940 source "drivers/acpi/Kconfig"
942 menuconfig APM
943 tristate "APM (Advanced Power Management) BIOS support"
944 depends on PM_SLEEP && !X86_VISWS
945 ---help---
946 APM is a BIOS specification for saving power using several different
947 techniques. This is mostly useful for battery powered laptops with
948 APM compliant BIOSes. If you say Y here, the system time will be
949 reset after a RESUME operation, the /proc/apm device will provide
950 battery status information, and user-space programs will receive
951 notification of APM "events" (e.g. battery status change).
953 If you select "Y" here, you can disable actual use of the APM
954 BIOS by passing the "apm=off" option to the kernel at boot time.
956 Note that the APM support is almost completely disabled for
957 machines with more than one CPU.
959 In order to use APM, you will need supporting software. For location
960 and more information, read <file:Documentation/pm.txt> and the
961 Battery Powered Linux mini-HOWTO, available from
962 <http://www.tldp.org/docs.html#howto>.
964 This driver does not spin down disk drives (see the hdparm(8)
965 manpage ("man 8 hdparm") for that), and it doesn't turn off
966 VESA-compliant "green" monitors.
968 This driver does not support the TI 4000M TravelMate and the ACER
969 486/DX4/75 because they don't have compliant BIOSes. Many "green"
970 desktop machines also don't have compliant BIOSes, and this driver
971 may cause those machines to panic during the boot phase.
973 Generally, if you don't have a battery in your machine, there isn't
974 much point in using this driver and you should say N. If you get
975 random kernel OOPSes or reboots that don't seem to be related to
976 anything, try disabling/enabling this option (or disabling/enabling
977 APM in your BIOS).
979 Some other things you should try when experiencing seemingly random,
980 "weird" problems:
982 1) make sure that you have enough swap space and that it is
983 enabled.
984 2) pass the "no-hlt" option to the kernel
985 3) switch on floating point emulation in the kernel and pass
986 the "no387" option to the kernel
987 4) pass the "floppy=nodma" option to the kernel
988 5) pass the "mem=4M" option to the kernel (thereby disabling
989 all but the first 4 MB of RAM)
990 6) make sure that the CPU is not over clocked.
991 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
992 8) disable the cache from your BIOS settings
993 9) install a fan for the video card or exchange video RAM
994 10) install a better fan for the CPU
995 11) exchange RAM chips
996 12) exchange the motherboard.
998 To compile this driver as a module, choose M here: the
999 module will be called apm.
1001 if APM
1003 config APM_IGNORE_USER_SUSPEND
1004 bool "Ignore USER SUSPEND"
1005 help
1006 This option will ignore USER SUSPEND requests. On machines with a
1007 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1008 series notebooks, it is necessary to say Y because of a BIOS bug.
1010 config APM_DO_ENABLE
1011 bool "Enable PM at boot time"
1012 ---help---
1013 Enable APM features at boot time. From page 36 of the APM BIOS
1014 specification: "When disabled, the APM BIOS does not automatically
1015 power manage devices, enter the Standby State, enter the Suspend
1016 State, or take power saving steps in response to CPU Idle calls."
1017 This driver will make CPU Idle calls when Linux is idle (unless this
1018 feature is turned off -- see "Do CPU IDLE calls", below). This
1019 should always save battery power, but more complicated APM features
1020 will be dependent on your BIOS implementation. You may need to turn
1021 this option off if your computer hangs at boot time when using APM
1022 support, or if it beeps continuously instead of suspending. Turn
1023 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1024 T400CDT. This is off by default since most machines do fine without
1025 this feature.
1027 config APM_CPU_IDLE
1028 bool "Make CPU Idle calls when idle"
1029 help
1030 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1031 On some machines, this can activate improved power savings, such as
1032 a slowed CPU clock rate, when the machine is idle. These idle calls
1033 are made after the idle loop has run for some length of time (e.g.,
1034 333 mS). On some machines, this will cause a hang at boot time or
1035 whenever the CPU becomes idle. (On machines with more than one CPU,
1036 this option does nothing.)
1038 config APM_DISPLAY_BLANK
1039 bool "Enable console blanking using APM"
1040 help
1041 Enable console blanking using the APM. Some laptops can use this to
1042 turn off the LCD backlight when the screen blanker of the Linux
1043 virtual console blanks the screen. Note that this is only used by
1044 the virtual console screen blanker, and won't turn off the backlight
1045 when using the X Window system. This also doesn't have anything to
1046 do with your VESA-compliant power-saving monitor. Further, this
1047 option doesn't work for all laptops -- it might not turn off your
1048 backlight at all, or it might print a lot of errors to the console,
1049 especially if you are using gpm.
1051 config APM_ALLOW_INTS
1052 bool "Allow interrupts during APM BIOS calls"
1053 help
1054 Normally we disable external interrupts while we are making calls to
1055 the APM BIOS as a measure to lessen the effects of a badly behaving
1056 BIOS implementation. The BIOS should reenable interrupts if it
1057 needs to. Unfortunately, some BIOSes do not -- especially those in
1058 many of the newer IBM Thinkpads. If you experience hangs when you
1059 suspend, try setting this to Y. Otherwise, say N.
1061 config APM_REAL_MODE_POWER_OFF
1062 bool "Use real mode APM BIOS call to power off"
1063 help
1064 Use real mode APM BIOS calls to switch off the computer. This is
1065 a work-around for a number of buggy BIOSes. Switch this option on if
1066 your computer crashes instead of powering off properly.
1068 endif # APM
1070 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1072 endmenu
1074 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1076 config PCI
1077 bool "PCI support" if !X86_VISWS
1078 depends on !X86_VOYAGER
1079 default y if X86_VISWS
1080 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1081 help
1082 Find out whether you have a PCI motherboard. PCI is the name of a
1083 bus system, i.e. the way the CPU talks to the other stuff inside
1084 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1085 VESA. If you have PCI, say Y, otherwise N.
1087 The PCI-HOWTO, available from
1088 <http://www.tldp.org/docs.html#howto>, contains valuable
1089 information about which PCI hardware does work under Linux and which
1090 doesn't.
1092 choice
1093 prompt "PCI access mode"
1094 depends on PCI && !X86_VISWS
1095 default PCI_GOANY
1096 ---help---
1097 On PCI systems, the BIOS can be used to detect the PCI devices and
1098 determine their configuration. However, some old PCI motherboards
1099 have BIOS bugs and may crash if this is done. Also, some embedded
1100 PCI-based systems don't have any BIOS at all. Linux can also try to
1101 detect the PCI hardware directly without using the BIOS.
1103 With this option, you can specify how Linux should detect the
1104 PCI devices. If you choose "BIOS", the BIOS will be used,
1105 if you choose "Direct", the BIOS won't be used, and if you
1106 choose "MMConfig", then PCI Express MMCONFIG will be used.
1107 If you choose "Any", the kernel will try MMCONFIG, then the
1108 direct access method and falls back to the BIOS if that doesn't
1109 work. If unsure, go with the default, which is "Any".
1111 config PCI_GOBIOS
1112 bool "BIOS"
1114 config PCI_GOMMCONFIG
1115 bool "MMConfig"
1117 config PCI_GODIRECT
1118 bool "Direct"
1120 config PCI_GOANY
1121 bool "Any"
1123 endchoice
1125 config PCI_BIOS
1126 bool
1127 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1128 default y
1130 config PCI_DIRECT
1131 bool
1132 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1133 default y
1135 config PCI_MMCONFIG
1136 bool
1137 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1138 default y
1140 source "drivers/pci/pcie/Kconfig"
1142 source "drivers/pci/Kconfig"
1144 config ISA_DMA_API
1145 bool
1146 default y
1148 config ISA
1149 bool "ISA support"
1150 depends on !(X86_VOYAGER || X86_VISWS)
1151 help
1152 Find out whether you have ISA slots on your motherboard. ISA is the
1153 name of a bus system, i.e. the way the CPU talks to the other stuff
1154 inside your box. Other bus systems are PCI, EISA, MicroChannel
1155 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1156 newer boards don't support it. If you have ISA, say Y, otherwise N.
1158 config EISA
1159 bool "EISA support"
1160 depends on ISA
1161 ---help---
1162 The Extended Industry Standard Architecture (EISA) bus was
1163 developed as an open alternative to the IBM MicroChannel bus.
1165 The EISA bus provided some of the features of the IBM MicroChannel
1166 bus while maintaining backward compatibility with cards made for
1167 the older ISA bus. The EISA bus saw limited use between 1988 and
1168 1995 when it was made obsolete by the PCI bus.
1170 Say Y here if you are building a kernel for an EISA-based machine.
1172 Otherwise, say N.
1174 source "drivers/eisa/Kconfig"
1176 config MCA
1177 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1178 default y if X86_VOYAGER
1179 help
1180 MicroChannel Architecture is found in some IBM PS/2 machines and
1181 laptops. It is a bus system similar to PCI or ISA. See
1182 <file:Documentation/mca.txt> (and especially the web page given
1183 there) before attempting to build an MCA bus kernel.
1185 source "drivers/mca/Kconfig"
1187 config SCx200
1188 tristate "NatSemi SCx200 support"
1189 depends on !X86_VOYAGER
1190 help
1191 This provides basic support for National Semiconductor's
1192 (now AMD's) Geode processors. The driver probes for the
1193 PCI-IDs of several on-chip devices, so its a good dependency
1194 for other scx200_* drivers.
1196 If compiled as a module, the driver is named scx200.
1198 config SCx200HR_TIMER
1199 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1200 depends on SCx200 && GENERIC_TIME
1201 default y
1202 help
1203 This driver provides a clocksource built upon the on-chip
1204 27MHz high-resolution timer. Its also a workaround for
1205 NSC Geode SC-1100's buggy TSC, which loses time when the
1206 processor goes idle (as is done by the scheduler). The
1207 other workaround is idle=poll boot option.
1209 config K8_NB
1210 def_bool y
1211 depends on AGP_AMD64
1213 source "drivers/pcmcia/Kconfig"
1215 source "drivers/pci/hotplug/Kconfig"
1217 endmenu
1219 menu "Executable file formats"
1221 source "fs/Kconfig.binfmt"
1223 endmenu
1225 source "net/Kconfig"
1227 source "drivers/Kconfig"
1229 source "fs/Kconfig"
1231 menuconfig INSTRUMENTATION
1232 bool "Instrumentation Support"
1233 depends on EXPERIMENTAL
1234 default y
1235 ---help---
1236 Say Y here to get to see options related to performance measurement,
1237 debugging, and testing. This option alone does not add any kernel code.
1239 If you say N, all options in this submenu will be skipped and disabled.
1241 if INSTRUMENTATION
1243 source "arch/i386/oprofile/Kconfig"
1245 config KPROBES
1246 bool "Kprobes"
1247 depends on KALLSYMS && MODULES
1248 help
1249 Kprobes allows you to trap at almost any kernel address and
1250 execute a callback function. register_kprobe() establishes
1251 a probepoint and specifies the callback. Kprobes is useful
1252 for kernel debugging, non-intrusive instrumentation and testing.
1253 If in doubt, say "N".
1255 endif # INSTRUMENTATION
1257 source "arch/i386/Kconfig.debug"
1259 source "security/Kconfig"
1261 source "crypto/Kconfig"
1263 source "lib/Kconfig"
1265 #
1266 # Use the generic interrupt handling code in kernel/irq/:
1267 #
1268 config GENERIC_HARDIRQS
1269 bool
1270 default y
1272 config GENERIC_IRQ_PROBE
1273 bool
1274 default y
1276 config GENERIC_PENDING_IRQ
1277 bool
1278 depends on GENERIC_HARDIRQS && SMP
1279 default y
1281 config X86_SMP
1282 bool
1283 depends on SMP && !X86_VOYAGER
1284 default y
1286 config X86_HT
1287 bool
1288 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1289 default y
1291 config X86_BIOS_REBOOT
1292 bool
1293 depends on !(X86_VISWS || X86_VOYAGER)
1294 default y
1296 config X86_TRAMPOLINE
1297 bool
1298 depends on X86_SMP || (X86_VOYAGER && SMP)
1299 default y
1301 config KTIME_SCALAR
1302 bool
1303 default y