2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
6 mainmenu "Linux Kernel Configuration"
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.
21 config CLOCKSOURCE_WATCHDOG
25 config GENERIC_CLOCKEVENTS
29 config GENERIC_CLOCKEVENTS_BROADCAST
33 config LOCKDEP_SUPPORT
37 config STACKTRACE_SUPPORT
41 config SEMAPHORE_SLEEPERS
60 config GENERIC_ISA_DMA
73 config GENERIC_HWEIGHT
77 config ARCH_MAY_HAVE_PC_FDC
87 menu "Processor type and features"
89 source "kernel/time/Kconfig"
92 bool "Symmetric multi-processing support"
94 This enables support for systems with more than one CPU. If you have
95 a system with only one CPU, like most personal computers, say N. If
96 you have a system with more than one CPU, say Y.
98 If you say N here, the kernel will run on single and multiprocessor
99 machines, but will use only one CPU of a multiprocessor machine. If
100 you say Y here, the kernel will run on many, but not all,
101 singleprocessor machines. On a singleprocessor machine, the kernel
102 will run faster if you say N here.
104 Note that if you say Y here and choose architecture "586" or
105 "Pentium" under "Processor family", the kernel will not work on 486
106 architectures. Similarly, multiprocessor kernels for the "PPro"
107 architecture may not work on all Pentium based boards.
109 People using multiprocessor machines who say Y here should also say
110 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
111 Management" code will be disabled if you say Y here.
113 See also the <file:Documentation/smp.txt>,
114 <file:Documentation/i386/IO-APIC.txt>,
115 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
116 <http://www.tldp.org/docs.html#howto>.
118 If you don't know what to do here, say N.
121 prompt "Subarchitecture Type"
127 Choose this option if your computer is a standard PC or compatible.
132 Select this for an AMD Elan processor.
134 Do not use this option for K6/Athlon/Opteron processors!
136 If unsure, choose "PC-compatible" instead.
141 Voyager is an MCA-based 32-way capable SMP architecture proprietary
142 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
146 If you do not specifically know you have a Voyager based machine,
147 say N here, otherwise the kernel you build will not be bootable.
150 bool "NUMAQ (IBM/Sequent)"
154 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
155 multiquad box. This changes the way that processors are bootstrapped,
156 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
157 You will need a new lynxer.elf file to flash your firmware with - send
158 email to <Martin.Bligh@us.ibm.com>.
161 bool "Summit/EXA (IBM x440)"
164 This option is needed for IBM systems that use the Summit/EXA chipset.
165 In particular, it is needed for the x440.
167 If you don't have one of these computers, you should say N here.
168 If you want to build a NUMA kernel, you must select ACPI.
171 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
174 This option is needed for the systems that have more than 8 CPUs
175 and if the system is not of any sub-arch type above.
177 If you don't have such a system, you should say N here.
180 bool "SGI 320/540 (Visual Workstation)"
182 The SGI Visual Workstation series is an IA32-based workstation
183 based on SGI systems chips with some legacy PC hardware attached.
185 Say Y here to create a kernel to run on the SGI 320 or 540.
187 A kernel compiled for the Visual Workstation will not run on PCs
188 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
190 config X86_GENERICARCH
191 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
193 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
194 It is intended for a generic binary kernel.
195 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
198 bool "Support for Unisys ES7000 IA32 series"
201 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
202 supposed to run on an IA32-based Unisys ES7000 system.
203 Only choose this option if you have such a system, otherwise you
209 bool "Paravirtualization support (EXPERIMENTAL)"
210 depends on EXPERIMENTAL
211 depends on !(X86_VISWS || X86_VOYAGER)
213 Paravirtualization is a way of running multiple instances of
214 Linux on the same machine, under a hypervisor. This option
215 changes the kernel so it can modify itself when it is run
216 under a hypervisor, improving performance significantly.
217 However, when run without a hypervisor the kernel is
218 theoretically slower. If in doubt, say N.
221 bool "VMI Paravirt-ops support"
222 depends on PARAVIRT && !NO_HZ
225 VMI provides a paravirtualized interface to multiple hypervisors
226 include VMware ESX server and Xen by connecting to a ROM module
227 provided by the hypervisor.
232 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
235 config HAVE_ARCH_PARSE_SRAT
240 config X86_SUMMIT_NUMA
243 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
245 config X86_CYCLONE_TIMER
248 depends on X86_SUMMIT || X86_GENERICARCH
250 config ES7000_CLUSTERED_APIC
253 depends on SMP && X86_ES7000 && MPENTIUMIII
255 source "arch/i386/Kconfig.cpu"
258 bool "HPET Timer Support"
260 This enables the use of the HPET for the kernel's internal timer.
261 HPET is the next generation timer replacing legacy 8254s.
262 You can safely choose Y here. However, HPET will only be
263 activated if the platform and the BIOS support this feature.
264 Otherwise the 8254 will be used for timing services.
266 Choose N to continue using the legacy 8254 timer.
268 config HPET_EMULATE_RTC
270 depends on HPET_TIMER && RTC=y
274 int "Maximum number of CPUs (2-255)"
277 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
280 This allows you to specify the maximum number of CPUs which this
281 kernel will support. The maximum supported value is 255 and the
282 minimum value which makes sense is 2.
284 This is purely to save memory - each supported CPU adds
285 approximately eight kilobytes to the kernel image.
288 bool "SMT (Hyperthreading) scheduler support"
291 SMT scheduler support improves the CPU scheduler's decision making
292 when dealing with Intel Pentium 4 chips with HyperThreading at a
293 cost of slightly increased overhead in some places. If unsure say
297 bool "Multi-core scheduler support"
301 Multi-core scheduler support improves the CPU scheduler's decision
302 making when dealing with multi-core CPU chips at a cost of slightly
303 increased overhead in some places. If unsure say N here.
305 source "kernel/Kconfig.preempt"
308 bool "Local APIC support on uniprocessors"
309 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
311 A local APIC (Advanced Programmable Interrupt Controller) is an
312 integrated interrupt controller in the CPU. If you have a single-CPU
313 system which has a processor with a local APIC, you can say Y here to
314 enable and use it. If you say Y here even though your machine doesn't
315 have a local APIC, then the kernel will still run with no slowdown at
316 all. The local APIC supports CPU-generated self-interrupts (timer,
317 performance counters), and the NMI watchdog which detects hard
321 bool "IO-APIC support on uniprocessors"
322 depends on X86_UP_APIC
324 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
325 SMP-capable replacement for PC-style interrupt controllers. Most
326 SMP systems and many recent uniprocessor systems have one.
328 If you have a single-CPU system with an IO-APIC, you can say Y here
329 to use it. If you say Y here even though your machine doesn't have
330 an IO-APIC, then the kernel will still run with no slowdown at all.
332 config X86_LOCAL_APIC
334 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
339 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
342 config X86_VISWS_APIC
348 bool "Machine Check Exception"
349 depends on !X86_VOYAGER
351 Machine Check Exception support allows the processor to notify the
352 kernel if it detects a problem (e.g. overheating, component failure).
353 The action the kernel takes depends on the severity of the problem,
354 ranging from a warning message on the console, to halting the machine.
355 Your processor must be a Pentium or newer to support this - check the
356 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
357 have a design flaw which leads to false MCE events - hence MCE is
358 disabled on all P5 processors, unless explicitly enabled with "mce"
359 as a boot argument. Similarly, if MCE is built in and creates a
360 problem on some new non-standard machine, you can boot with "nomce"
361 to disable it. MCE support simply ignores non-MCE processors like
362 the 386 and 486, so nearly everyone can say Y here.
364 config X86_MCE_NONFATAL
365 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
368 Enabling this feature starts a timer that triggers every 5 seconds which
369 will look at the machine check registers to see if anything happened.
370 Non-fatal problems automatically get corrected (but still logged).
371 Disable this if you don't want to see these messages.
372 Seeing the messages this option prints out may be indicative of dying hardware,
373 or out-of-spec (ie, overclocked) hardware.
374 This option only does something on certain CPUs.
375 (AMD Athlon/Duron and Intel Pentium 4)
377 config X86_MCE_P4THERMAL
378 bool "check for P4 thermal throttling interrupt."
379 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
381 Enabling this feature will cause a message to be printed when the P4
382 enters thermal throttling.
386 bool "Enable VM86 support" if EMBEDDED
388 This option is required by programs like DOSEMU to run 16-bit legacy
389 code on X86 processors. It also may be needed by software like
390 XFree86 to initialize some video cards via BIOS. Disabling this
391 option saves about 6k.
394 tristate "Toshiba Laptop support"
396 This adds a driver to safely access the System Management Mode of
397 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
398 not work on models with a Phoenix BIOS. The System Management Mode
399 is used to set the BIOS and power saving options on Toshiba portables.
401 For information on utilities to make use of this driver see the
402 Toshiba Linux utilities web site at:
403 <http://www.buzzard.org.uk/toshiba/>.
405 Say Y if you intend to run this kernel on a Toshiba portable.
409 tristate "Dell laptop support"
411 This adds a driver to safely access the System Management Mode
412 of the CPU on the Dell Inspiron 8000. The System Management Mode
413 is used to read cpu temperature and cooling fan status and to
414 control the fans on the I8K portables.
416 This driver has been tested only on the Inspiron 8000 but it may
417 also work with other Dell laptops. You can force loading on other
418 models by passing the parameter `force=1' to the module. Use at
421 For information on utilities to make use of this driver see the
422 I8K Linux utilities web site at:
423 <http://people.debian.org/~dz/i8k/>
425 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
428 config X86_REBOOTFIXUPS
429 bool "Enable X86 board specific fixups for reboot"
433 This enables chipset and/or board specific fixups to be done
434 in order to get reboot to work correctly. This is only needed on
435 some combinations of hardware and BIOS. The symptom, for which
436 this config is intended, is when reboot ends with a stalled/hung
439 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
442 Say Y if you want to enable the fixup. Currently, it's safe to
443 enable this option even if you don't need it.
447 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
450 If you say Y here and also to "/dev file system support" in the
451 'File systems' section, you will be able to update the microcode on
452 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
453 Pentium III, Pentium 4, Xeon etc. You will obviously need the
454 actual microcode binary data itself which is not shipped with the
457 For latest news and information on obtaining all the required
458 ingredients for this driver, check:
459 <http://www.urbanmyth.org/microcode/>.
461 To compile this driver as a module, choose M here: the
462 module will be called microcode.
464 config MICROCODE_OLD_INTERFACE
470 tristate "/dev/cpu/*/msr - Model-specific register support"
472 This device gives privileged processes access to the x86
473 Model-Specific Registers (MSRs). It is a character device with
474 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
475 MSR accesses are directed to a specific CPU on multi-processor
479 tristate "/dev/cpu/*/cpuid - CPU information support"
481 This device gives processes access to the x86 CPUID instruction to
482 be executed on a specific processor. It is a character device
483 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
486 source "drivers/firmware/Kconfig"
489 prompt "High Memory Support"
490 default HIGHMEM4G if !X86_NUMAQ
491 default HIGHMEM64G if X86_NUMAQ
495 depends on !X86_NUMAQ
497 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
498 However, the address space of 32-bit x86 processors is only 4
499 Gigabytes large. That means that, if you have a large amount of
500 physical memory, not all of it can be "permanently mapped" by the
501 kernel. The physical memory that's not permanently mapped is called
504 If you are compiling a kernel which will never run on a machine with
505 more than 1 Gigabyte total physical RAM, answer "off" here (default
506 choice and suitable for most users). This will result in a "3GB/1GB"
507 split: 3GB are mapped so that each process sees a 3GB virtual memory
508 space and the remaining part of the 4GB virtual memory space is used
509 by the kernel to permanently map as much physical memory as
512 If the machine has between 1 and 4 Gigabytes physical RAM, then
515 If more than 4 Gigabytes is used then answer "64GB" here. This
516 selection turns Intel PAE (Physical Address Extension) mode on.
517 PAE implements 3-level paging on IA32 processors. PAE is fully
518 supported by Linux, PAE mode is implemented on all recent Intel
519 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
520 then the kernel will not boot on CPUs that don't support PAE!
522 The actual amount of total physical memory will either be
523 auto detected or can be forced by using a kernel command line option
524 such as "mem=256M". (Try "man bootparam" or see the documentation of
525 your boot loader (lilo or loadlin) about how to pass options to the
526 kernel at boot time.)
528 If unsure, say "off".
532 depends on !X86_NUMAQ
534 Select this if you have a 32-bit processor and between 1 and 4
535 gigabytes of physical RAM.
539 depends on X86_CMPXCHG64
541 Select this if you have a 32-bit processor and more than 4
542 gigabytes of physical RAM.
547 depends on EXPERIMENTAL
548 prompt "Memory split" if EMBEDDED
551 Select the desired split between kernel and user memory.
553 If the address range available to the kernel is less than the
554 physical memory installed, the remaining memory will be available
555 as "high memory". Accessing high memory is a little more costly
556 than low memory, as it needs to be mapped into the kernel first.
557 Note that increasing the kernel address space limits the range
558 available to user programs, making the address space there
559 tighter. Selecting anything other than the default 3G/1G split
560 will also likely make your kernel incompatible with binary-only
563 If you are not absolutely sure what you are doing, leave this
567 bool "3G/1G user/kernel split"
568 config VMSPLIT_3G_OPT
570 bool "3G/1G user/kernel split (for full 1G low memory)"
572 bool "2G/2G user/kernel split"
574 bool "1G/3G user/kernel split"
579 default 0xB0000000 if VMSPLIT_3G_OPT
580 default 0x78000000 if VMSPLIT_2G
581 default 0x40000000 if VMSPLIT_1G
586 depends on HIGHMEM64G || HIGHMEM4G
591 depends on HIGHMEM64G
593 select RESOURCES_64BIT
595 # Common NUMA Features
597 bool "Numa Memory Allocation and Scheduler Support"
598 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
600 default y if (X86_NUMAQ || X86_SUMMIT)
602 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
603 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
607 default "4" if X86_NUMAQ
609 depends on NEED_MULTIPLE_NODES
611 config HAVE_ARCH_BOOTMEM_NODE
616 config ARCH_HAVE_MEMORY_PRESENT
618 depends on DISCONTIGMEM
621 config NEED_NODE_MEMMAP_SIZE
623 depends on DISCONTIGMEM || SPARSEMEM
626 config HAVE_ARCH_ALLOC_REMAP
631 config ARCH_FLATMEM_ENABLE
633 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
635 config ARCH_DISCONTIGMEM_ENABLE
639 config ARCH_DISCONTIGMEM_DEFAULT
643 config ARCH_SPARSEMEM_ENABLE
645 depends on (NUMA || (X86_PC && EXPERIMENTAL))
646 select SPARSEMEM_STATIC
648 config ARCH_SELECT_MEMORY_MODEL
650 depends on ARCH_SPARSEMEM_ENABLE
652 config ARCH_POPULATES_NODE_MAP
658 bool "Allocate 3rd-level pagetables from highmem"
659 depends on HIGHMEM4G || HIGHMEM64G
661 The VM uses one page table entry for each page of physical memory.
662 For systems with a lot of RAM, this can be wasteful of precious
663 low memory. Setting this option will put user-space page table
664 entries in high memory.
666 config MATH_EMULATION
667 bool "Math emulation"
669 Linux can emulate a math coprocessor (used for floating point
670 operations) if you don't have one. 486DX and Pentium processors have
671 a math coprocessor built in, 486SX and 386 do not, unless you added
672 a 487DX or 387, respectively. (The messages during boot time can
673 give you some hints here ["man dmesg"].) Everyone needs either a
674 coprocessor or this emulation.
676 If you don't have a math coprocessor, you need to say Y here; if you
677 say Y here even though you have a coprocessor, the coprocessor will
678 be used nevertheless. (This behavior can be changed with the kernel
679 command line option "no387", which comes handy if your coprocessor
680 is broken. Try "man bootparam" or see the documentation of your boot
681 loader (lilo or loadlin) about how to pass options to the kernel at
682 boot time.) This means that it is a good idea to say Y here if you
683 intend to use this kernel on different machines.
685 More information about the internals of the Linux math coprocessor
686 emulation can be found in <file:arch/i386/math-emu/README>.
688 If you are not sure, say Y; apart from resulting in a 66 KB bigger
689 kernel, it won't hurt.
692 bool "MTRR (Memory Type Range Register) support"
694 On Intel P6 family processors (Pentium Pro, Pentium II and later)
695 the Memory Type Range Registers (MTRRs) may be used to control
696 processor access to memory ranges. This is most useful if you have
697 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
698 allows bus write transfers to be combined into a larger transfer
699 before bursting over the PCI/AGP bus. This can increase performance
700 of image write operations 2.5 times or more. Saying Y here creates a
701 /proc/mtrr file which may be used to manipulate your processor's
702 MTRRs. Typically the X server should use this.
704 This code has a reasonably generic interface so that similar
705 control registers on other processors can be easily supported
708 The Cyrix 6x86, 6x86MX and M II processors have Address Range
709 Registers (ARRs) which provide a similar functionality to MTRRs. For
710 these, the ARRs are used to emulate the MTRRs.
711 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
712 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
713 write-combining. All of these processors are supported by this code
714 and it makes sense to say Y here if you have one of them.
716 Saying Y here also fixes a problem with buggy SMP BIOSes which only
717 set the MTRRs for the boot CPU and not for the secondary CPUs. This
718 can lead to all sorts of problems, so it's good to say Y here.
720 You can safely say Y even if your machine doesn't have MTRRs, you'll
721 just add about 9 KB to your kernel.
723 See <file:Documentation/mtrr.txt> for more information.
726 bool "Boot from EFI support"
730 This enables the kernel to boot on EFI platforms using
731 system configuration information passed to it from the firmware.
732 This also enables the kernel to use any EFI runtime services that are
733 available (such as the EFI variable services).
735 This option is only useful on systems that have EFI firmware
736 and will result in a kernel image that is ~8k larger. In addition,
737 you must use the latest ELILO loader available at
738 <http://elilo.sourceforge.net> in order to take advantage of
739 kernel initialization using EFI information (neither GRUB nor LILO know
740 anything about EFI). However, even with this option, the resultant
741 kernel should continue to boot on existing non-EFI platforms.
744 bool "Enable kernel irq balancing"
745 depends on SMP && X86_IO_APIC
748 The default yes will allow the kernel to do irq load balancing.
749 Saying no will keep the kernel from doing irq load balancing.
751 # turning this on wastes a bunch of space.
752 # Summit needs it only when NUMA is on
755 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
759 bool "Enable seccomp to safely compute untrusted bytecode"
763 This kernel feature is useful for number crunching applications
764 that may need to compute untrusted bytecode during their
765 execution. By using pipes or other transports made available to
766 the process as file descriptors supporting the read/write
767 syscalls, it's possible to isolate those applications in
768 their own address space using seccomp. Once seccomp is
769 enabled via /proc/<pid>/seccomp, it cannot be disabled
770 and the task is only allowed to execute a few safe syscalls
771 defined by each seccomp mode.
773 If unsure, say Y. Only embedded should say N here.
775 source kernel/Kconfig.hz
778 bool "kexec system call"
780 kexec is a system call that implements the ability to shutdown your
781 current kernel, and to start another kernel. It is like a reboot
782 but it is independent of the system firmware. And like a reboot
783 you can start any kernel with it, not just Linux.
785 The name comes from the similarity to the exec system call.
787 It is an ongoing process to be certain the hardware in a machine
788 is properly shutdown, so do not be surprised if this code does not
789 initially work for you. It may help to enable device hotplugging
790 support. As of this writing the exact hardware interface is
791 strongly in flux, so no good recommendation can be made.
794 bool "kernel crash dumps (EXPERIMENTAL)"
795 depends on EXPERIMENTAL
798 Generate crash dump after being started by kexec.
799 This should be normally only set in special crash dump kernels
800 which are loaded in the main kernel with kexec-tools into
801 a specially reserved region and then later executed after
802 a crash by kdump/kexec. The crash dump kernel must be compiled
803 to a memory address not used by the main kernel or BIOS using
805 For more details see Documentation/kdump/kdump.txt
807 config PHYSICAL_START
808 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
811 This gives the physical address where the kernel is loaded.
813 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
814 bzImage will decompress itself to above physical address and
815 run from there. Otherwise, bzImage will run from the address where
816 it has been loaded by the boot loader and will ignore above physical
819 In normal kdump cases one does not have to set/change this option
820 as now bzImage can be compiled as a completely relocatable image
821 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
822 address. This option is mainly useful for the folks who don't want
823 to use a bzImage for capturing the crash dump and want to use a
824 vmlinux instead. vmlinux is not relocatable hence a kernel needs
825 to be specifically compiled to run from a specific memory area
826 (normally a reserved region) and this option comes handy.
828 So if you are using bzImage for capturing the crash dump, leave
829 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
830 Otherwise if you plan to use vmlinux for capturing the crash dump
831 change this value to start of the reserved region (Typically 16MB
832 0x1000000). In other words, it can be set based on the "X" value as
833 specified in the "crashkernel=YM@XM" command line boot parameter
834 passed to the panic-ed kernel. Typically this parameter is set as
835 crashkernel=64M@16M. Please take a look at
836 Documentation/kdump/kdump.txt for more details about crash dumps.
838 Usage of bzImage for capturing the crash dump is recommended as
839 one does not have to build two kernels. Same kernel can be used
840 as production kernel and capture kernel. Above option should have
841 gone away after relocatable bzImage support is introduced. But it
842 is present because there are users out there who continue to use
843 vmlinux for dump capture. This option should go away down the
846 Don't change this unless you know what you are doing.
849 bool "Build a relocatable kernel(EXPERIMENTAL)"
850 depends on EXPERIMENTAL
852 This build a kernel image that retains relocation information
853 so it can be loaded someplace besides the default 1MB.
854 The relocations tend to the kernel binary about 10% larger,
855 but are discarded at runtime.
857 One use is for the kexec on panic case where the recovery kernel
858 must live at a different physical address than the primary
861 config PHYSICAL_ALIGN
862 hex "Alignment value to which kernel should be aligned"
864 range 0x2000 0x400000
866 This value puts the alignment restrictions on physical address
867 where kernel is loaded and run from. Kernel is compiled for an
868 address which meets above alignment restriction.
870 If bootloader loads the kernel at a non-aligned address and
871 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
872 address aligned to above value and run from there.
874 If bootloader loads the kernel at a non-aligned address and
875 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
876 load address and decompress itself to the address it has been
877 compiled for and run from there. The address for which kernel is
878 compiled already meets above alignment restrictions. Hence the
879 end result is that kernel runs from a physical address meeting
880 above alignment restrictions.
882 Don't change this unless you know what you are doing.
885 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
886 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
888 Say Y here to experiment with turning CPUs off and on, and to
889 enable suspend on SMP systems. CPUs can be controlled through
890 /sys/devices/system/cpu.
893 bool "Compat VDSO support"
897 Map the VDSO to the predictable old-style address too.
899 Say N here if you are running a sufficiently recent glibc
900 version (2.3.3 or later), to remove the high-mapped
901 VDSO mapping and to exclusively use the randomized VDSO.
907 config ARCH_ENABLE_MEMORY_HOTPLUG
911 menu "Power management options (ACPI, APM)"
912 depends on !X86_VOYAGER
914 source kernel/power/Kconfig
916 source "drivers/acpi/Kconfig"
918 menu "APM (Advanced Power Management) BIOS Support"
919 depends on PM && !X86_VISWS
922 tristate "APM (Advanced Power Management) BIOS support"
925 APM is a BIOS specification for saving power using several different
926 techniques. This is mostly useful for battery powered laptops with
927 APM compliant BIOSes. If you say Y here, the system time will be
928 reset after a RESUME operation, the /proc/apm device will provide
929 battery status information, and user-space programs will receive
930 notification of APM "events" (e.g. battery status change).
932 If you select "Y" here, you can disable actual use of the APM
933 BIOS by passing the "apm=off" option to the kernel at boot time.
935 Note that the APM support is almost completely disabled for
936 machines with more than one CPU.
938 In order to use APM, you will need supporting software. For location
939 and more information, read <file:Documentation/pm.txt> and the
940 Battery Powered Linux mini-HOWTO, available from
941 <http://www.tldp.org/docs.html#howto>.
943 This driver does not spin down disk drives (see the hdparm(8)
944 manpage ("man 8 hdparm") for that), and it doesn't turn off
945 VESA-compliant "green" monitors.
947 This driver does not support the TI 4000M TravelMate and the ACER
948 486/DX4/75 because they don't have compliant BIOSes. Many "green"
949 desktop machines also don't have compliant BIOSes, and this driver
950 may cause those machines to panic during the boot phase.
952 Generally, if you don't have a battery in your machine, there isn't
953 much point in using this driver and you should say N. If you get
954 random kernel OOPSes or reboots that don't seem to be related to
955 anything, try disabling/enabling this option (or disabling/enabling
958 Some other things you should try when experiencing seemingly random,
961 1) make sure that you have enough swap space and that it is
963 2) pass the "no-hlt" option to the kernel
964 3) switch on floating point emulation in the kernel and pass
965 the "no387" option to the kernel
966 4) pass the "floppy=nodma" option to the kernel
967 5) pass the "mem=4M" option to the kernel (thereby disabling
968 all but the first 4 MB of RAM)
969 6) make sure that the CPU is not over clocked.
970 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
971 8) disable the cache from your BIOS settings
972 9) install a fan for the video card or exchange video RAM
973 10) install a better fan for the CPU
974 11) exchange RAM chips
975 12) exchange the motherboard.
977 To compile this driver as a module, choose M here: the
978 module will be called apm.
980 config APM_IGNORE_USER_SUSPEND
981 bool "Ignore USER SUSPEND"
984 This option will ignore USER SUSPEND requests. On machines with a
985 compliant APM BIOS, you want to say N. However, on the NEC Versa M
986 series notebooks, it is necessary to say Y because of a BIOS bug.
989 bool "Enable PM at boot time"
992 Enable APM features at boot time. From page 36 of the APM BIOS
993 specification: "When disabled, the APM BIOS does not automatically
994 power manage devices, enter the Standby State, enter the Suspend
995 State, or take power saving steps in response to CPU Idle calls."
996 This driver will make CPU Idle calls when Linux is idle (unless this
997 feature is turned off -- see "Do CPU IDLE calls", below). This
998 should always save battery power, but more complicated APM features
999 will be dependent on your BIOS implementation. You may need to turn
1000 this option off if your computer hangs at boot time when using APM
1001 support, or if it beeps continuously instead of suspending. Turn
1002 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1003 T400CDT. This is off by default since most machines do fine without
1007 bool "Make CPU Idle calls when idle"
1010 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1011 On some machines, this can activate improved power savings, such as
1012 a slowed CPU clock rate, when the machine is idle. These idle calls
1013 are made after the idle loop has run for some length of time (e.g.,
1014 333 mS). On some machines, this will cause a hang at boot time or
1015 whenever the CPU becomes idle. (On machines with more than one CPU,
1016 this option does nothing.)
1018 config APM_DISPLAY_BLANK
1019 bool "Enable console blanking using APM"
1022 Enable console blanking using the APM. Some laptops can use this to
1023 turn off the LCD backlight when the screen blanker of the Linux
1024 virtual console blanks the screen. Note that this is only used by
1025 the virtual console screen blanker, and won't turn off the backlight
1026 when using the X Window system. This also doesn't have anything to
1027 do with your VESA-compliant power-saving monitor. Further, this
1028 option doesn't work for all laptops -- it might not turn off your
1029 backlight at all, or it might print a lot of errors to the console,
1030 especially if you are using gpm.
1032 config APM_RTC_IS_GMT
1033 bool "RTC stores time in GMT"
1036 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1037 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1040 It is in fact recommended to store GMT in your RTC, because then you
1041 don't have to worry about daylight savings time changes. The only
1042 reason not to use GMT in your RTC is if you also run a broken OS
1043 that doesn't understand GMT.
1045 config APM_ALLOW_INTS
1046 bool "Allow interrupts during APM BIOS calls"
1049 Normally we disable external interrupts while we are making calls to
1050 the APM BIOS as a measure to lessen the effects of a badly behaving
1051 BIOS implementation. The BIOS should reenable interrupts if it
1052 needs to. Unfortunately, some BIOSes do not -- especially those in
1053 many of the newer IBM Thinkpads. If you experience hangs when you
1054 suspend, try setting this to Y. Otherwise, say N.
1056 config APM_REAL_MODE_POWER_OFF
1057 bool "Use real mode APM BIOS call to power off"
1060 Use real mode APM BIOS calls to switch off the computer. This is
1061 a work-around for a number of buggy BIOSes. Switch this option on if
1062 your computer crashes instead of powering off properly.
1066 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1070 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1073 bool "PCI support" if !X86_VISWS
1074 depends on !X86_VOYAGER
1075 default y if X86_VISWS
1077 Find out whether you have a PCI motherboard. PCI is the name of a
1078 bus system, i.e. the way the CPU talks to the other stuff inside
1079 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1080 VESA. If you have PCI, say Y, otherwise N.
1082 The PCI-HOWTO, available from
1083 <http://www.tldp.org/docs.html#howto>, contains valuable
1084 information about which PCI hardware does work under Linux and which
1088 prompt "PCI access mode"
1089 depends on PCI && !X86_VISWS
1092 On PCI systems, the BIOS can be used to detect the PCI devices and
1093 determine their configuration. However, some old PCI motherboards
1094 have BIOS bugs and may crash if this is done. Also, some embedded
1095 PCI-based systems don't have any BIOS at all. Linux can also try to
1096 detect the PCI hardware directly without using the BIOS.
1098 With this option, you can specify how Linux should detect the
1099 PCI devices. If you choose "BIOS", the BIOS will be used,
1100 if you choose "Direct", the BIOS won't be used, and if you
1101 choose "MMConfig", then PCI Express MMCONFIG will be used.
1102 If you choose "Any", the kernel will try MMCONFIG, then the
1103 direct access method and falls back to the BIOS if that doesn't
1104 work. If unsure, go with the default, which is "Any".
1109 config PCI_GOMMCONFIG
1122 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1127 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1132 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1135 source "drivers/pci/pcie/Kconfig"
1137 source "drivers/pci/Kconfig"
1145 depends on !(X86_VOYAGER || X86_VISWS)
1147 Find out whether you have ISA slots on your motherboard. ISA is the
1148 name of a bus system, i.e. the way the CPU talks to the other stuff
1149 inside your box. Other bus systems are PCI, EISA, MicroChannel
1150 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1151 newer boards don't support it. If you have ISA, say Y, otherwise N.
1157 The Extended Industry Standard Architecture (EISA) bus was
1158 developed as an open alternative to the IBM MicroChannel bus.
1160 The EISA bus provided some of the features of the IBM MicroChannel
1161 bus while maintaining backward compatibility with cards made for
1162 the older ISA bus. The EISA bus saw limited use between 1988 and
1163 1995 when it was made obsolete by the PCI bus.
1165 Say Y here if you are building a kernel for an EISA-based machine.
1169 source "drivers/eisa/Kconfig"
1172 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1173 default y if X86_VOYAGER
1175 MicroChannel Architecture is found in some IBM PS/2 machines and
1176 laptops. It is a bus system similar to PCI or ISA. See
1177 <file:Documentation/mca.txt> (and especially the web page given
1178 there) before attempting to build an MCA bus kernel.
1180 source "drivers/mca/Kconfig"
1183 tristate "NatSemi SCx200 support"
1184 depends on !X86_VOYAGER
1186 This provides basic support for National Semiconductor's
1187 (now AMD's) Geode processors. The driver probes for the
1188 PCI-IDs of several on-chip devices, so its a good dependency
1189 for other scx200_* drivers.
1191 If compiled as a module, the driver is named scx200.
1193 config SCx200HR_TIMER
1194 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1195 depends on SCx200 && GENERIC_TIME
1198 This driver provides a clocksource built upon the on-chip
1199 27MHz high-resolution timer. Its also a workaround for
1200 NSC Geode SC-1100's buggy TSC, which loses time when the
1201 processor goes idle (as is done by the scheduler). The
1202 other workaround is idle=poll boot option.
1206 depends on AGP_AMD64
1208 source "drivers/pcmcia/Kconfig"
1210 source "drivers/pci/hotplug/Kconfig"
1214 menu "Executable file formats"
1216 source "fs/Kconfig.binfmt"
1220 source "net/Kconfig"
1222 source "drivers/Kconfig"
1226 menu "Instrumentation Support"
1227 depends on EXPERIMENTAL
1229 source "arch/i386/oprofile/Kconfig"
1232 bool "Kprobes (EXPERIMENTAL)"
1233 depends on KALLSYMS && EXPERIMENTAL && MODULES
1235 Kprobes allows you to trap at almost any kernel address and
1236 execute a callback function. register_kprobe() establishes
1237 a probepoint and specifies the callback. Kprobes is useful
1238 for kernel debugging, non-intrusive instrumentation and testing.
1239 If in doubt, say "N".
1242 source "arch/i386/Kconfig.debug"
1244 source "security/Kconfig"
1246 source "crypto/Kconfig"
1248 source "lib/Kconfig"
1251 # Use the generic interrupt handling code in kernel/irq/:
1253 config GENERIC_HARDIRQS
1257 config GENERIC_IRQ_PROBE
1261 config GENERIC_PENDING_IRQ
1263 depends on GENERIC_HARDIRQS && SMP
1268 depends on SMP && !X86_VOYAGER
1273 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1276 config X86_BIOS_REBOOT
1278 depends on !(X86_VISWS || X86_VOYAGER)
1281 config X86_TRAMPOLINE
1283 depends on X86_SMP || (X86_VOYAGER && SMP)
1295 Switches the regular HZ timer off when the system is going idle.
1296 This helps a hypervisor detect that the Linux system is idle,
1297 reducing the overhead of idle systems.
projects / linux-2.6 / blob