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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 LOCKDEP_SUPPORT
22 bool
23 default y
25 config STACKTRACE_SUPPORT
26 bool
27 default y
29 config SEMAPHORE_SLEEPERS
30 bool
31 default y
33 config X86
34 bool
35 default y
37 config MMU
38 bool
39 default y
41 config SBUS
42 bool
44 config GENERIC_ISA_DMA
45 bool
46 default y
48 config GENERIC_IOMAP
49 bool
50 default y
52 config GENERIC_HWEIGHT
53 bool
54 default y
56 config ARCH_MAY_HAVE_PC_FDC
57 bool
58 default y
60 config DMI
61 bool
62 default y
64 source "init/Kconfig"
66 menu "Processor type and features"
68 config SMP
69 bool "Symmetric multi-processing support"
70 ---help---
71 This enables support for systems with more than one CPU. If you have
72 a system with only one CPU, like most personal computers, say N. If
73 you have a system with more than one CPU, say Y.
75 If you say N here, the kernel will run on single and multiprocessor
76 machines, but will use only one CPU of a multiprocessor machine. If
77 you say Y here, the kernel will run on many, but not all,
78 singleprocessor machines. On a singleprocessor machine, the kernel
79 will run faster if you say N here.
81 Note that if you say Y here and choose architecture "586" or
82 "Pentium" under "Processor family", the kernel will not work on 486
83 architectures. Similarly, multiprocessor kernels for the "PPro"
84 architecture may not work on all Pentium based boards.
86 People using multiprocessor machines who say Y here should also say
87 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
88 Management" code will be disabled if you say Y here.
90 See also the <file:Documentation/smp.txt>,
91 <file:Documentation/i386/IO-APIC.txt>,
92 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
93 <http://www.tldp.org/docs.html#howto>.
95 If you don't know what to do here, say N.
97 choice
98 prompt "Subarchitecture Type"
99 default X86_PC
101 config X86_PC
102 bool "PC-compatible"
103 help
104 Choose this option if your computer is a standard PC or compatible.
106 config X86_ELAN
107 bool "AMD Elan"
108 help
109 Select this for an AMD Elan processor.
111 Do not use this option for K6/Athlon/Opteron processors!
113 If unsure, choose "PC-compatible" instead.
115 config X86_VOYAGER
116 bool "Voyager (NCR)"
117 help
118 Voyager is an MCA-based 32-way capable SMP architecture proprietary
119 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
121 *** WARNING ***
123 If you do not specifically know you have a Voyager based machine,
124 say N here, otherwise the kernel you build will not be bootable.
126 config X86_NUMAQ
127 bool "NUMAQ (IBM/Sequent)"
128 select SMP
129 select NUMA
130 help
131 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
132 multiquad box. This changes the way that processors are bootstrapped,
133 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
134 You will need a new lynxer.elf file to flash your firmware with - send
135 email to <Martin.Bligh@us.ibm.com>.
137 config X86_SUMMIT
138 bool "Summit/EXA (IBM x440)"
139 depends on SMP
140 help
141 This option is needed for IBM systems that use the Summit/EXA chipset.
142 In particular, it is needed for the x440.
144 If you don't have one of these computers, you should say N here.
145 If you want to build a NUMA kernel, you must select ACPI.
147 config X86_BIGSMP
148 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
149 depends on SMP
150 help
151 This option is needed for the systems that have more than 8 CPUs
152 and if the system is not of any sub-arch type above.
154 If you don't have such a system, you should say N here.
156 config X86_VISWS
157 bool "SGI 320/540 (Visual Workstation)"
158 help
159 The SGI Visual Workstation series is an IA32-based workstation
160 based on SGI systems chips with some legacy PC hardware attached.
162 Say Y here to create a kernel to run on the SGI 320 or 540.
164 A kernel compiled for the Visual Workstation will not run on PCs
165 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
167 config X86_GENERICARCH
168 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
169 help
170 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
171 It is intended for a generic binary kernel.
172 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
174 config X86_ES7000
175 bool "Support for Unisys ES7000 IA32 series"
176 depends on SMP
177 help
178 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
179 supposed to run on an IA32-based Unisys ES7000 system.
180 Only choose this option if you have such a system, otherwise you
181 should say N here.
183 endchoice
185 config PARAVIRT
186 bool "Paravirtualization support (EXPERIMENTAL)"
187 depends on EXPERIMENTAL
188 help
189 Paravirtualization is a way of running multiple instances of
190 Linux on the same machine, under a hypervisor. This option
191 changes the kernel so it can modify itself when it is run
192 under a hypervisor, improving performance significantly.
193 However, when run without a hypervisor the kernel is
194 theoretically slower. If in doubt, say N.
196 config ACPI_SRAT
197 bool
198 default y
199 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
200 select ACPI_NUMA
202 config HAVE_ARCH_PARSE_SRAT
203 bool
204 default y
205 depends on ACPI_SRAT
207 config X86_SUMMIT_NUMA
208 bool
209 default y
210 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
212 config X86_CYCLONE_TIMER
213 bool
214 default y
215 depends on X86_SUMMIT || X86_GENERICARCH
217 config ES7000_CLUSTERED_APIC
218 bool
219 default y
220 depends on SMP && X86_ES7000 && MPENTIUMIII
222 source "arch/i386/Kconfig.cpu"
224 config HPET_TIMER
225 bool "HPET Timer Support"
226 help
227 This enables the use of the HPET for the kernel's internal timer.
228 HPET is the next generation timer replacing legacy 8254s.
229 You can safely choose Y here. However, HPET will only be
230 activated if the platform and the BIOS support this feature.
231 Otherwise the 8254 will be used for timing services.
233 Choose N to continue using the legacy 8254 timer.
235 config HPET_EMULATE_RTC
236 bool
237 depends on HPET_TIMER && RTC=y
238 default y
240 config NR_CPUS
241 int "Maximum number of CPUs (2-255)"
242 range 2 255
243 depends on SMP
244 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
245 default "8"
246 help
247 This allows you to specify the maximum number of CPUs which this
248 kernel will support. The maximum supported value is 255 and the
249 minimum value which makes sense is 2.
251 This is purely to save memory - each supported CPU adds
252 approximately eight kilobytes to the kernel image.
254 config SCHED_SMT
255 bool "SMT (Hyperthreading) scheduler support"
256 depends on X86_HT
257 help
258 SMT scheduler support improves the CPU scheduler's decision making
259 when dealing with Intel Pentium 4 chips with HyperThreading at a
260 cost of slightly increased overhead in some places. If unsure say
261 N here.
263 config SCHED_MC
264 bool "Multi-core scheduler support"
265 depends on X86_HT
266 default y
267 help
268 Multi-core scheduler support improves the CPU scheduler's decision
269 making when dealing with multi-core CPU chips at a cost of slightly
270 increased overhead in some places. If unsure say N here.
272 source "kernel/Kconfig.preempt"
274 config X86_UP_APIC
275 bool "Local APIC support on uniprocessors"
276 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
277 help
278 A local APIC (Advanced Programmable Interrupt Controller) is an
279 integrated interrupt controller in the CPU. If you have a single-CPU
280 system which has a processor with a local APIC, you can say Y here to
281 enable and use it. If you say Y here even though your machine doesn't
282 have a local APIC, then the kernel will still run with no slowdown at
283 all. The local APIC supports CPU-generated self-interrupts (timer,
284 performance counters), and the NMI watchdog which detects hard
285 lockups.
287 config X86_UP_IOAPIC
288 bool "IO-APIC support on uniprocessors"
289 depends on X86_UP_APIC
290 help
291 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
292 SMP-capable replacement for PC-style interrupt controllers. Most
293 SMP systems and many recent uniprocessor systems have one.
295 If you have a single-CPU system with an IO-APIC, you can say Y here
296 to use it. If you say Y here even though your machine doesn't have
297 an IO-APIC, then the kernel will still run with no slowdown at all.
299 config X86_LOCAL_APIC
300 bool
301 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
302 default y
304 config X86_IO_APIC
305 bool
306 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
307 default y
309 config X86_VISWS_APIC
310 bool
311 depends on X86_VISWS
312 default y
314 config X86_MCE
315 bool "Machine Check Exception"
316 depends on !X86_VOYAGER
317 ---help---
318 Machine Check Exception support allows the processor to notify the
319 kernel if it detects a problem (e.g. overheating, component failure).
320 The action the kernel takes depends on the severity of the problem,
321 ranging from a warning message on the console, to halting the machine.
322 Your processor must be a Pentium or newer to support this - check the
323 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
324 have a design flaw which leads to false MCE events - hence MCE is
325 disabled on all P5 processors, unless explicitly enabled with "mce"
326 as a boot argument. Similarly, if MCE is built in and creates a
327 problem on some new non-standard machine, you can boot with "nomce"
328 to disable it. MCE support simply ignores non-MCE processors like
329 the 386 and 486, so nearly everyone can say Y here.
331 config X86_MCE_NONFATAL
332 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
333 depends on X86_MCE
334 help
335 Enabling this feature starts a timer that triggers every 5 seconds which
336 will look at the machine check registers to see if anything happened.
337 Non-fatal problems automatically get corrected (but still logged).
338 Disable this if you don't want to see these messages.
339 Seeing the messages this option prints out may be indicative of dying hardware,
340 or out-of-spec (ie, overclocked) hardware.
341 This option only does something on certain CPUs.
342 (AMD Athlon/Duron and Intel Pentium 4)
344 config X86_MCE_P4THERMAL
345 bool "check for P4 thermal throttling interrupt."
346 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
347 help
348 Enabling this feature will cause a message to be printed when the P4
349 enters thermal throttling.
351 config VM86
352 default y
353 bool "Enable VM86 support" if EMBEDDED
354 help
355 This option is required by programs like DOSEMU to run 16-bit legacy
356 code on X86 processors. It also may be needed by software like
357 XFree86 to initialize some video cards via BIOS. Disabling this
358 option saves about 6k.
360 config TOSHIBA
361 tristate "Toshiba Laptop support"
362 ---help---
363 This adds a driver to safely access the System Management Mode of
364 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
365 not work on models with a Phoenix BIOS. The System Management Mode
366 is used to set the BIOS and power saving options on Toshiba portables.
368 For information on utilities to make use of this driver see the
369 Toshiba Linux utilities web site at:
370 <http://www.buzzard.org.uk/toshiba/>.
372 Say Y if you intend to run this kernel on a Toshiba portable.
373 Say N otherwise.
375 config I8K
376 tristate "Dell laptop support"
377 ---help---
378 This adds a driver to safely access the System Management Mode
379 of the CPU on the Dell Inspiron 8000. The System Management Mode
380 is used to read cpu temperature and cooling fan status and to
381 control the fans on the I8K portables.
383 This driver has been tested only on the Inspiron 8000 but it may
384 also work with other Dell laptops. You can force loading on other
385 models by passing the parameter `force=1' to the module. Use at
386 your own risk.
388 For information on utilities to make use of this driver see the
389 I8K Linux utilities web site at:
390 <http://people.debian.org/~dz/i8k/>
392 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
393 Say N otherwise.
395 config X86_REBOOTFIXUPS
396 bool "Enable X86 board specific fixups for reboot"
397 depends on X86
398 default n
399 ---help---
400 This enables chipset and/or board specific fixups to be done
401 in order to get reboot to work correctly. This is only needed on
402 some combinations of hardware and BIOS. The symptom, for which
403 this config is intended, is when reboot ends with a stalled/hung
404 system.
406 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
407 combination.
409 Say Y if you want to enable the fixup. Currently, it's safe to
410 enable this option even if you don't need it.
411 Say N otherwise.
413 config MICROCODE
414 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
415 select FW_LOADER
416 ---help---
417 If you say Y here and also to "/dev file system support" in the
418 'File systems' section, you will be able to update the microcode on
419 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
420 Pentium III, Pentium 4, Xeon etc. You will obviously need the
421 actual microcode binary data itself which is not shipped with the
422 Linux kernel.
424 For latest news and information on obtaining all the required
425 ingredients for this driver, check:
426 <http://www.urbanmyth.org/microcode/>.
428 To compile this driver as a module, choose M here: the
429 module will be called microcode.
431 config MICROCODE_OLD_INTERFACE
432 bool
433 depends on MICROCODE
434 default y
436 config X86_MSR
437 tristate "/dev/cpu/*/msr - Model-specific register support"
438 help
439 This device gives privileged processes access to the x86
440 Model-Specific Registers (MSRs). It is a character device with
441 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
442 MSR accesses are directed to a specific CPU on multi-processor
443 systems.
445 config X86_CPUID
446 tristate "/dev/cpu/*/cpuid - CPU information support"
447 help
448 This device gives processes access to the x86 CPUID instruction to
449 be executed on a specific processor. It is a character device
450 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
451 /dev/cpu/31/cpuid.
453 source "drivers/firmware/Kconfig"
455 choice
456 prompt "High Memory Support"
457 default NOHIGHMEM
459 config NOHIGHMEM
460 bool "off"
461 depends on !X86_NUMAQ
462 ---help---
463 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
464 However, the address space of 32-bit x86 processors is only 4
465 Gigabytes large. That means that, if you have a large amount of
466 physical memory, not all of it can be "permanently mapped" by the
467 kernel. The physical memory that's not permanently mapped is called
468 "high memory".
470 If you are compiling a kernel which will never run on a machine with
471 more than 1 Gigabyte total physical RAM, answer "off" here (default
472 choice and suitable for most users). This will result in a "3GB/1GB"
473 split: 3GB are mapped so that each process sees a 3GB virtual memory
474 space and the remaining part of the 4GB virtual memory space is used
475 by the kernel to permanently map as much physical memory as
476 possible.
478 If the machine has between 1 and 4 Gigabytes physical RAM, then
479 answer "4GB" here.
481 If more than 4 Gigabytes is used then answer "64GB" here. This
482 selection turns Intel PAE (Physical Address Extension) mode on.
483 PAE implements 3-level paging on IA32 processors. PAE is fully
484 supported by Linux, PAE mode is implemented on all recent Intel
485 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
486 then the kernel will not boot on CPUs that don't support PAE!
488 The actual amount of total physical memory will either be
489 auto detected or can be forced by using a kernel command line option
490 such as "mem=256M". (Try "man bootparam" or see the documentation of
491 your boot loader (lilo or loadlin) about how to pass options to the
492 kernel at boot time.)
494 If unsure, say "off".
496 config HIGHMEM4G
497 bool "4GB"
498 depends on !X86_NUMAQ
499 help
500 Select this if you have a 32-bit processor and between 1 and 4
501 gigabytes of physical RAM.
503 config HIGHMEM64G
504 bool "64GB"
505 depends on X86_CMPXCHG64
506 help
507 Select this if you have a 32-bit processor and more than 4
508 gigabytes of physical RAM.
510 endchoice
512 choice
513 depends on EXPERIMENTAL
514 prompt "Memory split" if EMBEDDED
515 default VMSPLIT_3G
516 help
517 Select the desired split between kernel and user memory.
519 If the address range available to the kernel is less than the
520 physical memory installed, the remaining memory will be available
521 as "high memory". Accessing high memory is a little more costly
522 than low memory, as it needs to be mapped into the kernel first.
523 Note that increasing the kernel address space limits the range
524 available to user programs, making the address space there
525 tighter. Selecting anything other than the default 3G/1G split
526 will also likely make your kernel incompatible with binary-only
527 kernel modules.
529 If you are not absolutely sure what you are doing, leave this
530 option alone!
532 config VMSPLIT_3G
533 bool "3G/1G user/kernel split"
534 config VMSPLIT_3G_OPT
535 depends on !HIGHMEM
536 bool "3G/1G user/kernel split (for full 1G low memory)"
537 config VMSPLIT_2G
538 bool "2G/2G user/kernel split"
539 config VMSPLIT_1G
540 bool "1G/3G user/kernel split"
541 endchoice
543 config PAGE_OFFSET
544 hex
545 default 0xB0000000 if VMSPLIT_3G_OPT
546 default 0x78000000 if VMSPLIT_2G
547 default 0x40000000 if VMSPLIT_1G
548 default 0xC0000000
550 config HIGHMEM
551 bool
552 depends on HIGHMEM64G || HIGHMEM4G
553 default y
555 config X86_PAE
556 bool
557 depends on HIGHMEM64G
558 default y
559 select RESOURCES_64BIT
561 # Common NUMA Features
562 config NUMA
563 bool "Numa Memory Allocation and Scheduler Support"
564 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
565 default n if X86_PC
566 default y if (X86_NUMAQ || X86_SUMMIT)
568 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
569 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
571 config NODES_SHIFT
572 int
573 default "4" if X86_NUMAQ
574 default "3"
575 depends on NEED_MULTIPLE_NODES
577 config HAVE_ARCH_BOOTMEM_NODE
578 bool
579 depends on NUMA
580 default y
582 config ARCH_HAVE_MEMORY_PRESENT
583 bool
584 depends on DISCONTIGMEM
585 default y
587 config NEED_NODE_MEMMAP_SIZE
588 bool
589 depends on DISCONTIGMEM || SPARSEMEM
590 default y
592 config HAVE_ARCH_ALLOC_REMAP
593 bool
594 depends on NUMA
595 default y
597 config ARCH_FLATMEM_ENABLE
598 def_bool y
599 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
601 config ARCH_DISCONTIGMEM_ENABLE
602 def_bool y
603 depends on NUMA
605 config ARCH_DISCONTIGMEM_DEFAULT
606 def_bool y
607 depends on NUMA
609 config ARCH_SPARSEMEM_ENABLE
610 def_bool y
611 depends on (NUMA || (X86_PC && EXPERIMENTAL))
612 select SPARSEMEM_STATIC
614 config ARCH_SELECT_MEMORY_MODEL
615 def_bool y
616 depends on ARCH_SPARSEMEM_ENABLE
618 config ARCH_POPULATES_NODE_MAP
619 def_bool y
621 source "mm/Kconfig"
623 config HIGHPTE
624 bool "Allocate 3rd-level pagetables from highmem"
625 depends on HIGHMEM4G || HIGHMEM64G
626 help
627 The VM uses one page table entry for each page of physical memory.
628 For systems with a lot of RAM, this can be wasteful of precious
629 low memory. Setting this option will put user-space page table
630 entries in high memory.
632 config MATH_EMULATION
633 bool "Math emulation"
634 ---help---
635 Linux can emulate a math coprocessor (used for floating point
636 operations) if you don't have one. 486DX and Pentium processors have
637 a math coprocessor built in, 486SX and 386 do not, unless you added
638 a 487DX or 387, respectively. (The messages during boot time can
639 give you some hints here ["man dmesg"].) Everyone needs either a
640 coprocessor or this emulation.
642 If you don't have a math coprocessor, you need to say Y here; if you
643 say Y here even though you have a coprocessor, the coprocessor will
644 be used nevertheless. (This behavior can be changed with the kernel
645 command line option "no387", which comes handy if your coprocessor
646 is broken. Try "man bootparam" or see the documentation of your boot
647 loader (lilo or loadlin) about how to pass options to the kernel at
648 boot time.) This means that it is a good idea to say Y here if you
649 intend to use this kernel on different machines.
651 More information about the internals of the Linux math coprocessor
652 emulation can be found in <file:arch/i386/math-emu/README>.
654 If you are not sure, say Y; apart from resulting in a 66 KB bigger
655 kernel, it won't hurt.
657 config MTRR
658 bool "MTRR (Memory Type Range Register) support"
659 ---help---
660 On Intel P6 family processors (Pentium Pro, Pentium II and later)
661 the Memory Type Range Registers (MTRRs) may be used to control
662 processor access to memory ranges. This is most useful if you have
663 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
664 allows bus write transfers to be combined into a larger transfer
665 before bursting over the PCI/AGP bus. This can increase performance
666 of image write operations 2.5 times or more. Saying Y here creates a
667 /proc/mtrr file which may be used to manipulate your processor's
668 MTRRs. Typically the X server should use this.
670 This code has a reasonably generic interface so that similar
671 control registers on other processors can be easily supported
672 as well:
674 The Cyrix 6x86, 6x86MX and M II processors have Address Range
675 Registers (ARRs) which provide a similar functionality to MTRRs. For
676 these, the ARRs are used to emulate the MTRRs.
677 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
678 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
679 write-combining. All of these processors are supported by this code
680 and it makes sense to say Y here if you have one of them.
682 Saying Y here also fixes a problem with buggy SMP BIOSes which only
683 set the MTRRs for the boot CPU and not for the secondary CPUs. This
684 can lead to all sorts of problems, so it's good to say Y here.
686 You can safely say Y even if your machine doesn't have MTRRs, you'll
687 just add about 9 KB to your kernel.
689 See <file:Documentation/mtrr.txt> for more information.
691 config EFI
692 bool "Boot from EFI support"
693 depends on ACPI
694 default n
695 ---help---
696 This enables the kernel to boot on EFI platforms using
697 system configuration information passed to it from the firmware.
698 This also enables the kernel to use any EFI runtime services that are
699 available (such as the EFI variable services).
701 This option is only useful on systems that have EFI firmware
702 and will result in a kernel image that is ~8k larger. In addition,
703 you must use the latest ELILO loader available at
704 <http://elilo.sourceforge.net> in order to take advantage of
705 kernel initialization using EFI information (neither GRUB nor LILO know
706 anything about EFI). However, even with this option, the resultant
707 kernel should continue to boot on existing non-EFI platforms.
709 config IRQBALANCE
710 bool "Enable kernel irq balancing"
711 depends on SMP && X86_IO_APIC
712 default y
713 help
714 The default yes will allow the kernel to do irq load balancing.
715 Saying no will keep the kernel from doing irq load balancing.
717 # turning this on wastes a bunch of space.
718 # Summit needs it only when NUMA is on
719 config BOOT_IOREMAP
720 bool
721 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
722 default y
724 config REGPARM
725 bool "Use register arguments"
726 default y
727 help
728 Compile the kernel with -mregparm=3. This instructs gcc to use
729 a more efficient function call ABI which passes the first three
730 arguments of a function call via registers, which results in denser
731 and faster code.
733 If this option is disabled, then the default ABI of passing
734 arguments via the stack is used.
736 If unsure, say Y.
738 config SECCOMP
739 bool "Enable seccomp to safely compute untrusted bytecode"
740 depends on PROC_FS
741 default y
742 help
743 This kernel feature is useful for number crunching applications
744 that may need to compute untrusted bytecode during their
745 execution. By using pipes or other transports made available to
746 the process as file descriptors supporting the read/write
747 syscalls, it's possible to isolate those applications in
748 their own address space using seccomp. Once seccomp is
749 enabled via /proc/<pid>/seccomp, it cannot be disabled
750 and the task is only allowed to execute a few safe syscalls
751 defined by each seccomp mode.
753 If unsure, say Y. Only embedded should say N here.
755 source kernel/Kconfig.hz
757 config KEXEC
758 bool "kexec system call"
759 help
760 kexec is a system call that implements the ability to shutdown your
761 current kernel, and to start another kernel. It is like a reboot
762 but it is independent of the system firmware. And like a reboot
763 you can start any kernel with it, not just Linux.
765 The name comes from the similarity to the exec system call.
767 It is an ongoing process to be certain the hardware in a machine
768 is properly shutdown, so do not be surprised if this code does not
769 initially work for you. It may help to enable device hotplugging
770 support. As of this writing the exact hardware interface is
771 strongly in flux, so no good recommendation can be made.
773 config CRASH_DUMP
774 bool "kernel crash dumps (EXPERIMENTAL)"
775 depends on EXPERIMENTAL
776 depends on HIGHMEM
777 help
778 Generate crash dump after being started by kexec.
779 This should be normally only set in special crash dump kernels
780 which are loaded in the main kernel with kexec-tools into
781 a specially reserved region and then later executed after
782 a crash by kdump/kexec. The crash dump kernel must be compiled
783 to a memory address not used by the main kernel or BIOS using
784 PHYSICAL_START.
785 For more details see Documentation/kdump/kdump.txt
787 config RELOCATABLE
788 bool "Build a relocatable kernel(EXPERIMENTAL)"
789 depends on EXPERIMENTAL
790 help
791 This build a kernel image that retains relocation information
792 so it can be loaded someplace besides the default 1MB.
793 The relocations tend to the kernel binary about 10% larger,
794 but are discarded at runtime.
796 One use is for the kexec on panic case where the recovery kernel
797 must live at a different physical address than the primary
798 kernel.
800 config PHYSICAL_ALIGN
801 hex "Alignment value to which kernel should be aligned"
802 default "0x100000"
803 range 0x2000 0x400000
804 help
805 This value puts the alignment restrictions on physical address
806 where kernel is loaded and run from. Kernel is compiled for an
807 address which meets above alignment restriction.
809 If bootloader loads the kernel at a non-aligned address and
810 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
811 address aligned to above value and run from there.
813 If bootloader loads the kernel at a non-aligned address and
814 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
815 load address and decompress itself to the address it has been
816 compiled for and run from there. The address for which kernel is
817 compiled already meets above alignment restrictions. Hence the
818 end result is that kernel runs from a physical address meeting
819 above alignment restrictions.
821 Don't change this unless you know what you are doing.
823 config HOTPLUG_CPU
824 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
825 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
826 ---help---
827 Say Y here to experiment with turning CPUs off and on, and to
828 enable suspend on SMP systems. CPUs can be controlled through
829 /sys/devices/system/cpu.
831 config COMPAT_VDSO
832 bool "Compat VDSO support"
833 default y
834 depends on !PARAVIRT
835 help
836 Map the VDSO to the predictable old-style address too.
837 ---help---
838 Say N here if you are running a sufficiently recent glibc
839 version (2.3.3 or later), to remove the high-mapped
840 VDSO mapping and to exclusively use the randomized VDSO.
842 If unsure, say Y.
844 endmenu
846 config ARCH_ENABLE_MEMORY_HOTPLUG
847 def_bool y
848 depends on HIGHMEM
850 menu "Power management options (ACPI, APM)"
851 depends on !X86_VOYAGER
853 source kernel/power/Kconfig
855 source "drivers/acpi/Kconfig"
857 menu "APM (Advanced Power Management) BIOS Support"
858 depends on PM && !X86_VISWS
860 config APM
861 tristate "APM (Advanced Power Management) BIOS support"
862 depends on PM
863 ---help---
864 APM is a BIOS specification for saving power using several different
865 techniques. This is mostly useful for battery powered laptops with
866 APM compliant BIOSes. If you say Y here, the system time will be
867 reset after a RESUME operation, the /proc/apm device will provide
868 battery status information, and user-space programs will receive
869 notification of APM "events" (e.g. battery status change).
871 If you select "Y" here, you can disable actual use of the APM
872 BIOS by passing the "apm=off" option to the kernel at boot time.
874 Note that the APM support is almost completely disabled for
875 machines with more than one CPU.
877 In order to use APM, you will need supporting software. For location
878 and more information, read <file:Documentation/pm.txt> and the
879 Battery Powered Linux mini-HOWTO, available from
880 <http://www.tldp.org/docs.html#howto>.
882 This driver does not spin down disk drives (see the hdparm(8)
883 manpage ("man 8 hdparm") for that), and it doesn't turn off
884 VESA-compliant "green" monitors.
886 This driver does not support the TI 4000M TravelMate and the ACER
887 486/DX4/75 because they don't have compliant BIOSes. Many "green"
888 desktop machines also don't have compliant BIOSes, and this driver
889 may cause those machines to panic during the boot phase.
891 Generally, if you don't have a battery in your machine, there isn't
892 much point in using this driver and you should say N. If you get
893 random kernel OOPSes or reboots that don't seem to be related to
894 anything, try disabling/enabling this option (or disabling/enabling
895 APM in your BIOS).
897 Some other things you should try when experiencing seemingly random,
898 "weird" problems:
900 1) make sure that you have enough swap space and that it is
901 enabled.
902 2) pass the "no-hlt" option to the kernel
903 3) switch on floating point emulation in the kernel and pass
904 the "no387" option to the kernel
905 4) pass the "floppy=nodma" option to the kernel
906 5) pass the "mem=4M" option to the kernel (thereby disabling
907 all but the first 4 MB of RAM)
908 6) make sure that the CPU is not over clocked.
909 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
910 8) disable the cache from your BIOS settings
911 9) install a fan for the video card or exchange video RAM
912 10) install a better fan for the CPU
913 11) exchange RAM chips
914 12) exchange the motherboard.
916 To compile this driver as a module, choose M here: the
917 module will be called apm.
919 config APM_IGNORE_USER_SUSPEND
920 bool "Ignore USER SUSPEND"
921 depends on APM
922 help
923 This option will ignore USER SUSPEND requests. On machines with a
924 compliant APM BIOS, you want to say N. However, on the NEC Versa M
925 series notebooks, it is necessary to say Y because of a BIOS bug.
927 config APM_DO_ENABLE
928 bool "Enable PM at boot time"
929 depends on APM
930 ---help---
931 Enable APM features at boot time. From page 36 of the APM BIOS
932 specification: "When disabled, the APM BIOS does not automatically
933 power manage devices, enter the Standby State, enter the Suspend
934 State, or take power saving steps in response to CPU Idle calls."
935 This driver will make CPU Idle calls when Linux is idle (unless this
936 feature is turned off -- see "Do CPU IDLE calls", below). This
937 should always save battery power, but more complicated APM features
938 will be dependent on your BIOS implementation. You may need to turn
939 this option off if your computer hangs at boot time when using APM
940 support, or if it beeps continuously instead of suspending. Turn
941 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
942 T400CDT. This is off by default since most machines do fine without
943 this feature.
945 config APM_CPU_IDLE
946 bool "Make CPU Idle calls when idle"
947 depends on APM
948 help
949 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
950 On some machines, this can activate improved power savings, such as
951 a slowed CPU clock rate, when the machine is idle. These idle calls
952 are made after the idle loop has run for some length of time (e.g.,
953 333 mS). On some machines, this will cause a hang at boot time or
954 whenever the CPU becomes idle. (On machines with more than one CPU,
955 this option does nothing.)
957 config APM_DISPLAY_BLANK
958 bool "Enable console blanking using APM"
959 depends on APM
960 help
961 Enable console blanking using the APM. Some laptops can use this to
962 turn off the LCD backlight when the screen blanker of the Linux
963 virtual console blanks the screen. Note that this is only used by
964 the virtual console screen blanker, and won't turn off the backlight
965 when using the X Window system. This also doesn't have anything to
966 do with your VESA-compliant power-saving monitor. Further, this
967 option doesn't work for all laptops -- it might not turn off your
968 backlight at all, or it might print a lot of errors to the console,
969 especially if you are using gpm.
971 config APM_RTC_IS_GMT
972 bool "RTC stores time in GMT"
973 depends on APM
974 help
975 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
976 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
977 stores localtime.
979 It is in fact recommended to store GMT in your RTC, because then you
980 don't have to worry about daylight savings time changes. The only
981 reason not to use GMT in your RTC is if you also run a broken OS
982 that doesn't understand GMT.
984 config APM_ALLOW_INTS
985 bool "Allow interrupts during APM BIOS calls"
986 depends on APM
987 help
988 Normally we disable external interrupts while we are making calls to
989 the APM BIOS as a measure to lessen the effects of a badly behaving
990 BIOS implementation. The BIOS should reenable interrupts if it
991 needs to. Unfortunately, some BIOSes do not -- especially those in
992 many of the newer IBM Thinkpads. If you experience hangs when you
993 suspend, try setting this to Y. Otherwise, say N.
995 config APM_REAL_MODE_POWER_OFF
996 bool "Use real mode APM BIOS call to power off"
997 depends on APM
998 help
999 Use real mode APM BIOS calls to switch off the computer. This is
1000 a work-around for a number of buggy BIOSes. Switch this option on if
1001 your computer crashes instead of powering off properly.
1003 endmenu
1005 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1007 endmenu
1009 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1011 config PCI
1012 bool "PCI support" if !X86_VISWS
1013 depends on !X86_VOYAGER
1014 default y if X86_VISWS
1015 help
1016 Find out whether you have a PCI motherboard. PCI is the name of a
1017 bus system, i.e. the way the CPU talks to the other stuff inside
1018 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1019 VESA. If you have PCI, say Y, otherwise N.
1021 The PCI-HOWTO, available from
1022 <http://www.tldp.org/docs.html#howto>, contains valuable
1023 information about which PCI hardware does work under Linux and which
1024 doesn't.
1026 choice
1027 prompt "PCI access mode"
1028 depends on PCI && !X86_VISWS
1029 default PCI_GOANY
1030 ---help---
1031 On PCI systems, the BIOS can be used to detect the PCI devices and
1032 determine their configuration. However, some old PCI motherboards
1033 have BIOS bugs and may crash if this is done. Also, some embedded
1034 PCI-based systems don't have any BIOS at all. Linux can also try to
1035 detect the PCI hardware directly without using the BIOS.
1037 With this option, you can specify how Linux should detect the
1038 PCI devices. If you choose "BIOS", the BIOS will be used,
1039 if you choose "Direct", the BIOS won't be used, and if you
1040 choose "MMConfig", then PCI Express MMCONFIG will be used.
1041 If you choose "Any", the kernel will try MMCONFIG, then the
1042 direct access method and falls back to the BIOS if that doesn't
1043 work. If unsure, go with the default, which is "Any".
1045 config PCI_GOBIOS
1046 bool "BIOS"
1048 config PCI_GOMMCONFIG
1049 bool "MMConfig"
1051 config PCI_GODIRECT
1052 bool "Direct"
1054 config PCI_GOANY
1055 bool "Any"
1057 endchoice
1059 config PCI_BIOS
1060 bool
1061 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1062 default y
1064 config PCI_DIRECT
1065 bool
1066 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1067 default y
1069 config PCI_MMCONFIG
1070 bool
1071 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1072 default y
1074 source "drivers/pci/pcie/Kconfig"
1076 source "drivers/pci/Kconfig"
1078 config ISA_DMA_API
1079 bool
1080 default y
1082 config ISA
1083 bool "ISA support"
1084 depends on !(X86_VOYAGER || X86_VISWS)
1085 help
1086 Find out whether you have ISA slots on your motherboard. ISA is the
1087 name of a bus system, i.e. the way the CPU talks to the other stuff
1088 inside your box. Other bus systems are PCI, EISA, MicroChannel
1089 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1090 newer boards don't support it. If you have ISA, say Y, otherwise N.
1092 config EISA
1093 bool "EISA support"
1094 depends on ISA
1095 ---help---
1096 The Extended Industry Standard Architecture (EISA) bus was
1097 developed as an open alternative to the IBM MicroChannel bus.
1099 The EISA bus provided some of the features of the IBM MicroChannel
1100 bus while maintaining backward compatibility with cards made for
1101 the older ISA bus. The EISA bus saw limited use between 1988 and
1102 1995 when it was made obsolete by the PCI bus.
1104 Say Y here if you are building a kernel for an EISA-based machine.
1106 Otherwise, say N.
1108 source "drivers/eisa/Kconfig"
1110 config MCA
1111 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1112 default y if X86_VOYAGER
1113 help
1114 MicroChannel Architecture is found in some IBM PS/2 machines and
1115 laptops. It is a bus system similar to PCI or ISA. See
1116 <file:Documentation/mca.txt> (and especially the web page given
1117 there) before attempting to build an MCA bus kernel.
1119 source "drivers/mca/Kconfig"
1121 config SCx200
1122 tristate "NatSemi SCx200 support"
1123 depends on !X86_VOYAGER
1124 help
1125 This provides basic support for National Semiconductor's
1126 (now AMD's) Geode processors. The driver probes for the
1127 PCI-IDs of several on-chip devices, so its a good dependency
1128 for other scx200_* drivers.
1130 If compiled as a module, the driver is named scx200.
1132 config SCx200HR_TIMER
1133 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1134 depends on SCx200 && GENERIC_TIME
1135 default y
1136 help
1137 This driver provides a clocksource built upon the on-chip
1138 27MHz high-resolution timer. Its also a workaround for
1139 NSC Geode SC-1100's buggy TSC, which loses time when the
1140 processor goes idle (as is done by the scheduler). The
1141 other workaround is idle=poll boot option.
1143 config K8_NB
1144 def_bool y
1145 depends on AGP_AMD64
1147 source "drivers/pcmcia/Kconfig"
1149 source "drivers/pci/hotplug/Kconfig"
1151 endmenu
1153 menu "Executable file formats"
1155 source "fs/Kconfig.binfmt"
1157 endmenu
1159 source "net/Kconfig"
1161 source "drivers/Kconfig"
1163 source "fs/Kconfig"
1165 menu "Instrumentation Support"
1166 depends on EXPERIMENTAL
1168 source "arch/i386/oprofile/Kconfig"
1170 config KPROBES
1171 bool "Kprobes (EXPERIMENTAL)"
1172 depends on KALLSYMS && EXPERIMENTAL && MODULES
1173 help
1174 Kprobes allows you to trap at almost any kernel address and
1175 execute a callback function. register_kprobe() establishes
1176 a probepoint and specifies the callback. Kprobes is useful
1177 for kernel debugging, non-intrusive instrumentation and testing.
1178 If in doubt, say "N".
1179 endmenu
1181 source "arch/i386/Kconfig.debug"
1183 source "security/Kconfig"
1185 source "crypto/Kconfig"
1187 source "lib/Kconfig"
1189 #
1190 # Use the generic interrupt handling code in kernel/irq/:
1191 #
1192 config GENERIC_HARDIRQS
1193 bool
1194 default y
1196 config GENERIC_IRQ_PROBE
1197 bool
1198 default y
1200 config GENERIC_PENDING_IRQ
1201 bool
1202 depends on GENERIC_HARDIRQS && SMP
1203 default y
1205 config X86_SMP
1206 bool
1207 depends on SMP && !X86_VOYAGER
1208 default y
1210 config X86_HT
1211 bool
1212 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1213 default y
1215 config X86_BIOS_REBOOT
1216 bool
1217 depends on !(X86_VISWS || X86_VOYAGER)
1218 default y
1220 config X86_TRAMPOLINE
1221 bool
1222 depends on X86_SMP || (X86_VOYAGER && SMP)
1223 default y
1225 config KTIME_SCALAR
1226 bool
1227 default y