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
32 depends on X86_LOCAL_APIC
34 config LOCKDEP_SUPPORT
38 config STACKTRACE_SUPPORT
42 config SEMAPHORE_SLEEPERS
65 config GENERIC_ISA_DMA
78 config GENERIC_HWEIGHT
82 config ARCH_MAY_HAVE_PC_FDC
92 menu "Processor type and features"
94 source "kernel/time/Kconfig"
97 bool "Symmetric multi-processing support"
99 This enables support for systems with more than one CPU. If you have
100 a system with only one CPU, like most personal computers, say N. If
101 you have a system with more than one CPU, say Y.
103 If you say N here, the kernel will run on single and multiprocessor
104 machines, but will use only one CPU of a multiprocessor machine. If
105 you say Y here, the kernel will run on many, but not all,
106 singleprocessor machines. On a singleprocessor machine, the kernel
107 will run faster if you say N here.
109 Note that if you say Y here and choose architecture "586" or
110 "Pentium" under "Processor family", the kernel will not work on 486
111 architectures. Similarly, multiprocessor kernels for the "PPro"
112 architecture may not work on all Pentium based boards.
114 People using multiprocessor machines who say Y here should also say
115 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
116 Management" code will be disabled if you say Y here.
118 See also the <file:Documentation/smp.txt>,
119 <file:Documentation/i386/IO-APIC.txt>,
120 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
121 <http://www.tldp.org/docs.html#howto>.
123 If you don't know what to do here, say N.
126 prompt "Subarchitecture Type"
132 Choose this option if your computer is a standard PC or compatible.
137 Select this for an AMD Elan processor.
139 Do not use this option for K6/Athlon/Opteron processors!
141 If unsure, choose "PC-compatible" instead.
146 Voyager is an MCA-based 32-way capable SMP architecture proprietary
147 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
151 If you do not specifically know you have a Voyager based machine,
152 say N here, otherwise the kernel you build will not be bootable.
155 bool "NUMAQ (IBM/Sequent)"
159 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
160 multiquad box. This changes the way that processors are bootstrapped,
161 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
162 You will need a new lynxer.elf file to flash your firmware with - send
163 email to <Martin.Bligh@us.ibm.com>.
166 bool "Summit/EXA (IBM x440)"
169 This option is needed for IBM systems that use the Summit/EXA chipset.
170 In particular, it is needed for the x440.
172 If you don't have one of these computers, you should say N here.
173 If you want to build a NUMA kernel, you must select ACPI.
176 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
179 This option is needed for the systems that have more than 8 CPUs
180 and if the system is not of any sub-arch type above.
182 If you don't have such a system, you should say N here.
185 bool "SGI 320/540 (Visual Workstation)"
187 The SGI Visual Workstation series is an IA32-based workstation
188 based on SGI systems chips with some legacy PC hardware attached.
190 Say Y here to create a kernel to run on the SGI 320 or 540.
192 A kernel compiled for the Visual Workstation will not run on PCs
193 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
195 config X86_GENERICARCH
196 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
198 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
199 It is intended for a generic binary kernel.
200 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
203 bool "Support for Unisys ES7000 IA32 series"
206 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
207 supposed to run on an IA32-based Unisys ES7000 system.
208 Only choose this option if you have such a system, otherwise you
214 bool "Paravirtualization support (EXPERIMENTAL)"
215 depends on EXPERIMENTAL
216 depends on !(X86_VISWS || X86_VOYAGER)
218 Paravirtualization is a way of running multiple instances of
219 Linux on the same machine, under a hypervisor. This option
220 changes the kernel so it can modify itself when it is run
221 under a hypervisor, improving performance significantly.
222 However, when run without a hypervisor the kernel is
223 theoretically slower. If in doubt, say N.
225 source "arch/i386/xen/Kconfig"
228 bool "VMI Paravirt-ops support"
231 VMI provides a paravirtualized interface to the VMware ESX server
232 (it could be used by other hypervisors in theory too, but is not
233 at the moment), by linking the kernel to a GPL-ed ROM module
234 provided by the hypervisor.
239 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
242 config HAVE_ARCH_PARSE_SRAT
247 config X86_SUMMIT_NUMA
250 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
252 config X86_CYCLONE_TIMER
255 depends on X86_SUMMIT || X86_GENERICARCH
257 config ES7000_CLUSTERED_APIC
260 depends on SMP && X86_ES7000 && MPENTIUMIII
262 source "arch/i386/Kconfig.cpu"
265 bool "HPET Timer Support"
267 This enables the use of the HPET for the kernel's internal timer.
268 HPET is the next generation timer replacing legacy 8254s.
269 You can safely choose Y here. However, HPET will only be
270 activated if the platform and the BIOS support this feature.
271 Otherwise the 8254 will be used for timing services.
273 Choose N to continue using the legacy 8254 timer.
275 config HPET_EMULATE_RTC
277 depends on HPET_TIMER && RTC=y
281 int "Maximum number of CPUs (2-255)"
284 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
287 This allows you to specify the maximum number of CPUs which this
288 kernel will support. The maximum supported value is 255 and the
289 minimum value which makes sense is 2.
291 This is purely to save memory - each supported CPU adds
292 approximately eight kilobytes to the kernel image.
295 bool "SMT (Hyperthreading) scheduler support"
298 SMT scheduler support improves the CPU scheduler's decision making
299 when dealing with Intel Pentium 4 chips with HyperThreading at a
300 cost of slightly increased overhead in some places. If unsure say
304 bool "Multi-core scheduler support"
308 Multi-core scheduler support improves the CPU scheduler's decision
309 making when dealing with multi-core CPU chips at a cost of slightly
310 increased overhead in some places. If unsure say N here.
312 source "kernel/Kconfig.preempt"
315 bool "Local APIC support on uniprocessors"
316 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
318 A local APIC (Advanced Programmable Interrupt Controller) is an
319 integrated interrupt controller in the CPU. If you have a single-CPU
320 system which has a processor with a local APIC, you can say Y here to
321 enable and use it. If you say Y here even though your machine doesn't
322 have a local APIC, then the kernel will still run with no slowdown at
323 all. The local APIC supports CPU-generated self-interrupts (timer,
324 performance counters), and the NMI watchdog which detects hard
328 bool "IO-APIC support on uniprocessors"
329 depends on X86_UP_APIC
331 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
332 SMP-capable replacement for PC-style interrupt controllers. Most
333 SMP systems and many recent uniprocessor systems have one.
335 If you have a single-CPU system with an IO-APIC, you can say Y here
336 to use it. If you say Y here even though your machine doesn't have
337 an IO-APIC, then the kernel will still run with no slowdown at all.
339 config X86_LOCAL_APIC
341 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
346 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
349 config X86_VISWS_APIC
355 bool "Machine Check Exception"
356 depends on !X86_VOYAGER
358 Machine Check Exception support allows the processor to notify the
359 kernel if it detects a problem (e.g. overheating, component failure).
360 The action the kernel takes depends on the severity of the problem,
361 ranging from a warning message on the console, to halting the machine.
362 Your processor must be a Pentium or newer to support this - check the
363 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
364 have a design flaw which leads to false MCE events - hence MCE is
365 disabled on all P5 processors, unless explicitly enabled with "mce"
366 as a boot argument. Similarly, if MCE is built in and creates a
367 problem on some new non-standard machine, you can boot with "nomce"
368 to disable it. MCE support simply ignores non-MCE processors like
369 the 386 and 486, so nearly everyone can say Y here.
371 config X86_MCE_NONFATAL
372 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
375 Enabling this feature starts a timer that triggers every 5 seconds which
376 will look at the machine check registers to see if anything happened.
377 Non-fatal problems automatically get corrected (but still logged).
378 Disable this if you don't want to see these messages.
379 Seeing the messages this option prints out may be indicative of dying hardware,
380 or out-of-spec (ie, overclocked) hardware.
381 This option only does something on certain CPUs.
382 (AMD Athlon/Duron and Intel Pentium 4)
384 config X86_MCE_P4THERMAL
385 bool "check for P4 thermal throttling interrupt."
386 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
388 Enabling this feature will cause a message to be printed when the P4
389 enters thermal throttling.
393 bool "Enable VM86 support" if EMBEDDED
395 This option is required by programs like DOSEMU to run 16-bit legacy
396 code on X86 processors. It also may be needed by software like
397 XFree86 to initialize some video cards via BIOS. Disabling this
398 option saves about 6k.
401 tristate "Toshiba Laptop support"
403 This adds a driver to safely access the System Management Mode of
404 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
405 not work on models with a Phoenix BIOS. The System Management Mode
406 is used to set the BIOS and power saving options on Toshiba portables.
408 For information on utilities to make use of this driver see the
409 Toshiba Linux utilities web site at:
410 <http://www.buzzard.org.uk/toshiba/>.
412 Say Y if you intend to run this kernel on a Toshiba portable.
416 tristate "Dell laptop support"
418 This adds a driver to safely access the System Management Mode
419 of the CPU on the Dell Inspiron 8000. The System Management Mode
420 is used to read cpu temperature and cooling fan status and to
421 control the fans on the I8K portables.
423 This driver has been tested only on the Inspiron 8000 but it may
424 also work with other Dell laptops. You can force loading on other
425 models by passing the parameter `force=1' to the module. Use at
428 For information on utilities to make use of this driver see the
429 I8K Linux utilities web site at:
430 <http://people.debian.org/~dz/i8k/>
432 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
435 config X86_REBOOTFIXUPS
436 bool "Enable X86 board specific fixups for reboot"
440 This enables chipset and/or board specific fixups to be done
441 in order to get reboot to work correctly. This is only needed on
442 some combinations of hardware and BIOS. The symptom, for which
443 this config is intended, is when reboot ends with a stalled/hung
446 Currently, the only fixup is for the Geode machines using
447 CS5530A and CS5536 chipsets.
449 Say Y if you want to enable the fixup. Currently, it's safe to
450 enable this option even if you don't need it.
454 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
457 If you say Y here and also to "/dev file system support" in the
458 'File systems' section, you will be able to update the microcode on
459 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
460 Pentium III, Pentium 4, Xeon etc. You will obviously need the
461 actual microcode binary data itself which is not shipped with the
464 For latest news and information on obtaining all the required
465 ingredients for this driver, check:
466 <http://www.urbanmyth.org/microcode/>.
468 To compile this driver as a module, choose M here: the
469 module will be called microcode.
471 config MICROCODE_OLD_INTERFACE
477 tristate "/dev/cpu/*/msr - Model-specific register support"
479 This device gives privileged processes access to the x86
480 Model-Specific Registers (MSRs). It is a character device with
481 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
482 MSR accesses are directed to a specific CPU on multi-processor
486 tristate "/dev/cpu/*/cpuid - CPU information support"
488 This device gives processes access to the x86 CPUID instruction to
489 be executed on a specific processor. It is a character device
490 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
493 source "drivers/firmware/Kconfig"
496 prompt "High Memory Support"
497 default HIGHMEM4G if !X86_NUMAQ
498 default HIGHMEM64G if X86_NUMAQ
502 depends on !X86_NUMAQ
504 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
505 However, the address space of 32-bit x86 processors is only 4
506 Gigabytes large. That means that, if you have a large amount of
507 physical memory, not all of it can be "permanently mapped" by the
508 kernel. The physical memory that's not permanently mapped is called
511 If you are compiling a kernel which will never run on a machine with
512 more than 1 Gigabyte total physical RAM, answer "off" here (default
513 choice and suitable for most users). This will result in a "3GB/1GB"
514 split: 3GB are mapped so that each process sees a 3GB virtual memory
515 space and the remaining part of the 4GB virtual memory space is used
516 by the kernel to permanently map as much physical memory as
519 If the machine has between 1 and 4 Gigabytes physical RAM, then
522 If more than 4 Gigabytes is used then answer "64GB" here. This
523 selection turns Intel PAE (Physical Address Extension) mode on.
524 PAE implements 3-level paging on IA32 processors. PAE is fully
525 supported by Linux, PAE mode is implemented on all recent Intel
526 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
527 then the kernel will not boot on CPUs that don't support PAE!
529 The actual amount of total physical memory will either be
530 auto detected or can be forced by using a kernel command line option
531 such as "mem=256M". (Try "man bootparam" or see the documentation of
532 your boot loader (lilo or loadlin) about how to pass options to the
533 kernel at boot time.)
535 If unsure, say "off".
539 depends on !X86_NUMAQ
541 Select this if you have a 32-bit processor and between 1 and 4
542 gigabytes of physical RAM.
546 depends on !M386 && !M486
548 Select this if you have a 32-bit processor and more than 4
549 gigabytes of physical RAM.
554 depends on EXPERIMENTAL
555 prompt "Memory split" if EMBEDDED
558 Select the desired split between kernel and user memory.
560 If the address range available to the kernel is less than the
561 physical memory installed, the remaining memory will be available
562 as "high memory". Accessing high memory is a little more costly
563 than low memory, as it needs to be mapped into the kernel first.
564 Note that increasing the kernel address space limits the range
565 available to user programs, making the address space there
566 tighter. Selecting anything other than the default 3G/1G split
567 will also likely make your kernel incompatible with binary-only
570 If you are not absolutely sure what you are doing, leave this
574 bool "3G/1G user/kernel split"
575 config VMSPLIT_3G_OPT
577 bool "3G/1G user/kernel split (for full 1G low memory)"
579 bool "2G/2G user/kernel split"
580 config VMSPLIT_2G_OPT
582 bool "2G/2G user/kernel split (for full 2G low memory)"
584 bool "1G/3G user/kernel split"
589 default 0xB0000000 if VMSPLIT_3G_OPT
590 default 0x80000000 if VMSPLIT_2G
591 default 0x78000000 if VMSPLIT_2G_OPT
592 default 0x40000000 if VMSPLIT_1G
597 depends on HIGHMEM64G || HIGHMEM4G
602 depends on HIGHMEM64G
604 select RESOURCES_64BIT
606 # Common NUMA Features
608 bool "Numa Memory Allocation and Scheduler Support"
609 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
611 default y if (X86_NUMAQ || X86_SUMMIT)
613 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
614 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
618 default "4" if X86_NUMAQ
620 depends on NEED_MULTIPLE_NODES
622 config HAVE_ARCH_BOOTMEM_NODE
627 config ARCH_HAVE_MEMORY_PRESENT
629 depends on DISCONTIGMEM
632 config NEED_NODE_MEMMAP_SIZE
634 depends on DISCONTIGMEM || SPARSEMEM
637 config HAVE_ARCH_ALLOC_REMAP
642 config ARCH_FLATMEM_ENABLE
644 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
646 config ARCH_DISCONTIGMEM_ENABLE
650 config ARCH_DISCONTIGMEM_DEFAULT
654 config ARCH_SPARSEMEM_ENABLE
656 depends on (NUMA || (X86_PC && EXPERIMENTAL))
657 select SPARSEMEM_STATIC
659 config ARCH_SELECT_MEMORY_MODEL
661 depends on ARCH_SPARSEMEM_ENABLE
663 config ARCH_POPULATES_NODE_MAP
669 bool "Allocate 3rd-level pagetables from highmem"
670 depends on HIGHMEM4G || HIGHMEM64G
672 The VM uses one page table entry for each page of physical memory.
673 For systems with a lot of RAM, this can be wasteful of precious
674 low memory. Setting this option will put user-space page table
675 entries in high memory.
677 config MATH_EMULATION
678 bool "Math emulation"
680 Linux can emulate a math coprocessor (used for floating point
681 operations) if you don't have one. 486DX and Pentium processors have
682 a math coprocessor built in, 486SX and 386 do not, unless you added
683 a 487DX or 387, respectively. (The messages during boot time can
684 give you some hints here ["man dmesg"].) Everyone needs either a
685 coprocessor or this emulation.
687 If you don't have a math coprocessor, you need to say Y here; if you
688 say Y here even though you have a coprocessor, the coprocessor will
689 be used nevertheless. (This behavior can be changed with the kernel
690 command line option "no387", which comes handy if your coprocessor
691 is broken. Try "man bootparam" or see the documentation of your boot
692 loader (lilo or loadlin) about how to pass options to the kernel at
693 boot time.) This means that it is a good idea to say Y here if you
694 intend to use this kernel on different machines.
696 More information about the internals of the Linux math coprocessor
697 emulation can be found in <file:arch/i386/math-emu/README>.
699 If you are not sure, say Y; apart from resulting in a 66 KB bigger
700 kernel, it won't hurt.
703 bool "MTRR (Memory Type Range Register) support"
705 On Intel P6 family processors (Pentium Pro, Pentium II and later)
706 the Memory Type Range Registers (MTRRs) may be used to control
707 processor access to memory ranges. This is most useful if you have
708 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
709 allows bus write transfers to be combined into a larger transfer
710 before bursting over the PCI/AGP bus. This can increase performance
711 of image write operations 2.5 times or more. Saying Y here creates a
712 /proc/mtrr file which may be used to manipulate your processor's
713 MTRRs. Typically the X server should use this.
715 This code has a reasonably generic interface so that similar
716 control registers on other processors can be easily supported
719 The Cyrix 6x86, 6x86MX and M II processors have Address Range
720 Registers (ARRs) which provide a similar functionality to MTRRs. For
721 these, the ARRs are used to emulate the MTRRs.
722 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
723 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
724 write-combining. All of these processors are supported by this code
725 and it makes sense to say Y here if you have one of them.
727 Saying Y here also fixes a problem with buggy SMP BIOSes which only
728 set the MTRRs for the boot CPU and not for the secondary CPUs. This
729 can lead to all sorts of problems, so it's good to say Y here.
731 You can safely say Y even if your machine doesn't have MTRRs, you'll
732 just add about 9 KB to your kernel.
734 See <file:Documentation/mtrr.txt> for more information.
737 bool "Boot from EFI support"
741 This enables the kernel to boot on EFI platforms using
742 system configuration information passed to it from the firmware.
743 This also enables the kernel to use any EFI runtime services that are
744 available (such as the EFI variable services).
746 This option is only useful on systems that have EFI firmware
747 and will result in a kernel image that is ~8k larger. In addition,
748 you must use the latest ELILO loader available at
749 <http://elilo.sourceforge.net> in order to take advantage of
750 kernel initialization using EFI information (neither GRUB nor LILO know
751 anything about EFI). However, even with this option, the resultant
752 kernel should continue to boot on existing non-EFI platforms.
755 bool "Enable kernel irq balancing"
756 depends on SMP && X86_IO_APIC
759 The default yes will allow the kernel to do irq load balancing.
760 Saying no will keep the kernel from doing irq load balancing.
762 # turning this on wastes a bunch of space.
763 # Summit needs it only when NUMA is on
766 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
770 bool "Enable seccomp to safely compute untrusted bytecode"
774 This kernel feature is useful for number crunching applications
775 that may need to compute untrusted bytecode during their
776 execution. By using pipes or other transports made available to
777 the process as file descriptors supporting the read/write
778 syscalls, it's possible to isolate those applications in
779 their own address space using seccomp. Once seccomp is
780 enabled via /proc/<pid>/seccomp, it cannot be disabled
781 and the task is only allowed to execute a few safe syscalls
782 defined by each seccomp mode.
784 If unsure, say Y. Only embedded should say N here.
786 source kernel/Kconfig.hz
789 bool "kexec system call"
791 kexec is a system call that implements the ability to shutdown your
792 current kernel, and to start another kernel. It is like a reboot
793 but it is independent of the system firmware. And like a reboot
794 you can start any kernel with it, not just Linux.
796 The name comes from the similarity to the exec system call.
798 It is an ongoing process to be certain the hardware in a machine
799 is properly shutdown, so do not be surprised if this code does not
800 initially work for you. It may help to enable device hotplugging
801 support. As of this writing the exact hardware interface is
802 strongly in flux, so no good recommendation can be made.
805 bool "kernel crash dumps (EXPERIMENTAL)"
806 depends on EXPERIMENTAL
809 Generate crash dump after being started by kexec.
810 This should be normally only set in special crash dump kernels
811 which are loaded in the main kernel with kexec-tools into
812 a specially reserved region and then later executed after
813 a crash by kdump/kexec. The crash dump kernel must be compiled
814 to a memory address not used by the main kernel or BIOS using
816 For more details see Documentation/kdump/kdump.txt
818 config PHYSICAL_START
819 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
822 This gives the physical address where the kernel is loaded.
824 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
825 bzImage will decompress itself to above physical address and
826 run from there. Otherwise, bzImage will run from the address where
827 it has been loaded by the boot loader and will ignore above physical
830 In normal kdump cases one does not have to set/change this option
831 as now bzImage can be compiled as a completely relocatable image
832 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
833 address. This option is mainly useful for the folks who don't want
834 to use a bzImage for capturing the crash dump and want to use a
835 vmlinux instead. vmlinux is not relocatable hence a kernel needs
836 to be specifically compiled to run from a specific memory area
837 (normally a reserved region) and this option comes handy.
839 So if you are using bzImage for capturing the crash dump, leave
840 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
841 Otherwise if you plan to use vmlinux for capturing the crash dump
842 change this value to start of the reserved region (Typically 16MB
843 0x1000000). In other words, it can be set based on the "X" value as
844 specified in the "crashkernel=YM@XM" command line boot parameter
845 passed to the panic-ed kernel. Typically this parameter is set as
846 crashkernel=64M@16M. Please take a look at
847 Documentation/kdump/kdump.txt for more details about crash dumps.
849 Usage of bzImage for capturing the crash dump is recommended as
850 one does not have to build two kernels. Same kernel can be used
851 as production kernel and capture kernel. Above option should have
852 gone away after relocatable bzImage support is introduced. But it
853 is present because there are users out there who continue to use
854 vmlinux for dump capture. This option should go away down the
857 Don't change this unless you know what you are doing.
860 bool "Build a relocatable kernel(EXPERIMENTAL)"
861 depends on EXPERIMENTAL
863 This builds a kernel image that retains relocation information
864 so it can be loaded someplace besides the default 1MB.
865 The relocations tend to make the kernel binary about 10% larger,
866 but are discarded at runtime.
868 One use is for the kexec on panic case where the recovery kernel
869 must live at a different physical address than the primary
872 config PHYSICAL_ALIGN
873 hex "Alignment value to which kernel should be aligned"
875 range 0x2000 0x400000
877 This value puts the alignment restrictions on physical address
878 where kernel is loaded and run from. Kernel is compiled for an
879 address which meets above alignment restriction.
881 If bootloader loads the kernel at a non-aligned address and
882 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
883 address aligned to above value and run from there.
885 If bootloader loads the kernel at a non-aligned address and
886 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
887 load address and decompress itself to the address it has been
888 compiled for and run from there. The address for which kernel is
889 compiled already meets above alignment restrictions. Hence the
890 end result is that kernel runs from a physical address meeting
891 above alignment restrictions.
893 Don't change this unless you know what you are doing.
896 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
897 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
899 Say Y here to experiment with turning CPUs off and on, and to
900 enable suspend on SMP systems. CPUs can be controlled through
901 /sys/devices/system/cpu.
904 bool "Compat VDSO support"
907 Map the VDSO to the predictable old-style address too.
909 Say N here if you are running a sufficiently recent glibc
910 version (2.3.3 or later), to remove the high-mapped
911 VDSO mapping and to exclusively use the randomized VDSO.
917 config ARCH_ENABLE_MEMORY_HOTPLUG
921 menu "Power management options (ACPI, APM)"
922 depends on !X86_VOYAGER
924 source kernel/power/Kconfig
926 source "drivers/acpi/Kconfig"
929 tristate "APM (Advanced Power Management) BIOS support"
930 depends on PM && !X86_VISWS
932 APM is a BIOS specification for saving power using several different
933 techniques. This is mostly useful for battery powered laptops with
934 APM compliant BIOSes. If you say Y here, the system time will be
935 reset after a RESUME operation, the /proc/apm device will provide
936 battery status information, and user-space programs will receive
937 notification of APM "events" (e.g. battery status change).
939 If you select "Y" here, you can disable actual use of the APM
940 BIOS by passing the "apm=off" option to the kernel at boot time.
942 Note that the APM support is almost completely disabled for
943 machines with more than one CPU.
945 In order to use APM, you will need supporting software. For location
946 and more information, read <file:Documentation/pm.txt> and the
947 Battery Powered Linux mini-HOWTO, available from
948 <http://www.tldp.org/docs.html#howto>.
950 This driver does not spin down disk drives (see the hdparm(8)
951 manpage ("man 8 hdparm") for that), and it doesn't turn off
952 VESA-compliant "green" monitors.
954 This driver does not support the TI 4000M TravelMate and the ACER
955 486/DX4/75 because they don't have compliant BIOSes. Many "green"
956 desktop machines also don't have compliant BIOSes, and this driver
957 may cause those machines to panic during the boot phase.
959 Generally, if you don't have a battery in your machine, there isn't
960 much point in using this driver and you should say N. If you get
961 random kernel OOPSes or reboots that don't seem to be related to
962 anything, try disabling/enabling this option (or disabling/enabling
965 Some other things you should try when experiencing seemingly random,
968 1) make sure that you have enough swap space and that it is
970 2) pass the "no-hlt" option to the kernel
971 3) switch on floating point emulation in the kernel and pass
972 the "no387" option to the kernel
973 4) pass the "floppy=nodma" option to the kernel
974 5) pass the "mem=4M" option to the kernel (thereby disabling
975 all but the first 4 MB of RAM)
976 6) make sure that the CPU is not over clocked.
977 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
978 8) disable the cache from your BIOS settings
979 9) install a fan for the video card or exchange video RAM
980 10) install a better fan for the CPU
981 11) exchange RAM chips
982 12) exchange the motherboard.
984 To compile this driver as a module, choose M here: the
985 module will be called apm.
989 config APM_IGNORE_USER_SUSPEND
990 bool "Ignore USER SUSPEND"
992 This option will ignore USER SUSPEND requests. On machines with a
993 compliant APM BIOS, you want to say N. However, on the NEC Versa M
994 series notebooks, it is necessary to say Y because of a BIOS bug.
997 bool "Enable PM at boot time"
999 Enable APM features at boot time. From page 36 of the APM BIOS
1000 specification: "When disabled, the APM BIOS does not automatically
1001 power manage devices, enter the Standby State, enter the Suspend
1002 State, or take power saving steps in response to CPU Idle calls."
1003 This driver will make CPU Idle calls when Linux is idle (unless this
1004 feature is turned off -- see "Do CPU IDLE calls", below). This
1005 should always save battery power, but more complicated APM features
1006 will be dependent on your BIOS implementation. You may need to turn
1007 this option off if your computer hangs at boot time when using APM
1008 support, or if it beeps continuously instead of suspending. Turn
1009 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1010 T400CDT. This is off by default since most machines do fine without
1014 bool "Make CPU Idle calls when idle"
1016 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1017 On some machines, this can activate improved power savings, such as
1018 a slowed CPU clock rate, when the machine is idle. These idle calls
1019 are made after the idle loop has run for some length of time (e.g.,
1020 333 mS). On some machines, this will cause a hang at boot time or
1021 whenever the CPU becomes idle. (On machines with more than one CPU,
1022 this option does nothing.)
1024 config APM_DISPLAY_BLANK
1025 bool "Enable console blanking using APM"
1027 Enable console blanking using the APM. Some laptops can use this to
1028 turn off the LCD backlight when the screen blanker of the Linux
1029 virtual console blanks the screen. Note that this is only used by
1030 the virtual console screen blanker, and won't turn off the backlight
1031 when using the X Window system. This also doesn't have anything to
1032 do with your VESA-compliant power-saving monitor. Further, this
1033 option doesn't work for all laptops -- it might not turn off your
1034 backlight at all, or it might print a lot of errors to the console,
1035 especially if you are using gpm.
1037 config APM_ALLOW_INTS
1038 bool "Allow interrupts during APM BIOS calls"
1040 Normally we disable external interrupts while we are making calls to
1041 the APM BIOS as a measure to lessen the effects of a badly behaving
1042 BIOS implementation. The BIOS should reenable interrupts if it
1043 needs to. Unfortunately, some BIOSes do not -- especially those in
1044 many of the newer IBM Thinkpads. If you experience hangs when you
1045 suspend, try setting this to Y. Otherwise, say N.
1047 config APM_REAL_MODE_POWER_OFF
1048 bool "Use real mode APM BIOS call to power off"
1050 Use real mode APM BIOS calls to switch off the computer. This is
1051 a work-around for a number of buggy BIOSes. Switch this option on if
1052 your computer crashes instead of powering off properly.
1056 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1060 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1063 bool "PCI support" if !X86_VISWS
1064 depends on !X86_VOYAGER
1065 default y if X86_VISWS
1066 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1068 Find out whether you have a PCI motherboard. PCI is the name of a
1069 bus system, i.e. the way the CPU talks to the other stuff inside
1070 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1071 VESA. If you have PCI, say Y, otherwise N.
1073 The PCI-HOWTO, available from
1074 <http://www.tldp.org/docs.html#howto>, contains valuable
1075 information about which PCI hardware does work under Linux and which
1079 prompt "PCI access mode"
1080 depends on PCI && !X86_VISWS
1083 On PCI systems, the BIOS can be used to detect the PCI devices and
1084 determine their configuration. However, some old PCI motherboards
1085 have BIOS bugs and may crash if this is done. Also, some embedded
1086 PCI-based systems don't have any BIOS at all. Linux can also try to
1087 detect the PCI hardware directly without using the BIOS.
1089 With this option, you can specify how Linux should detect the
1090 PCI devices. If you choose "BIOS", the BIOS will be used,
1091 if you choose "Direct", the BIOS won't be used, and if you
1092 choose "MMConfig", then PCI Express MMCONFIG will be used.
1093 If you choose "Any", the kernel will try MMCONFIG, then the
1094 direct access method and falls back to the BIOS if that doesn't
1095 work. If unsure, go with the default, which is "Any".
1100 config PCI_GOMMCONFIG
1113 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1118 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1123 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1126 source "drivers/pci/pcie/Kconfig"
1128 source "drivers/pci/Kconfig"
1136 depends on !(X86_VOYAGER || X86_VISWS)
1138 Find out whether you have ISA slots on your motherboard. ISA is the
1139 name of a bus system, i.e. the way the CPU talks to the other stuff
1140 inside your box. Other bus systems are PCI, EISA, MicroChannel
1141 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1142 newer boards don't support it. If you have ISA, say Y, otherwise N.
1148 The Extended Industry Standard Architecture (EISA) bus was
1149 developed as an open alternative to the IBM MicroChannel bus.
1151 The EISA bus provided some of the features of the IBM MicroChannel
1152 bus while maintaining backward compatibility with cards made for
1153 the older ISA bus. The EISA bus saw limited use between 1988 and
1154 1995 when it was made obsolete by the PCI bus.
1156 Say Y here if you are building a kernel for an EISA-based machine.
1160 source "drivers/eisa/Kconfig"
1163 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1164 default y if X86_VOYAGER
1166 MicroChannel Architecture is found in some IBM PS/2 machines and
1167 laptops. It is a bus system similar to PCI or ISA. See
1168 <file:Documentation/mca.txt> (and especially the web page given
1169 there) before attempting to build an MCA bus kernel.
1171 source "drivers/mca/Kconfig"
1174 tristate "NatSemi SCx200 support"
1175 depends on !X86_VOYAGER
1177 This provides basic support for National Semiconductor's
1178 (now AMD's) Geode processors. The driver probes for the
1179 PCI-IDs of several on-chip devices, so its a good dependency
1180 for other scx200_* drivers.
1182 If compiled as a module, the driver is named scx200.
1184 config SCx200HR_TIMER
1185 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1186 depends on SCx200 && GENERIC_TIME
1189 This driver provides a clocksource built upon the on-chip
1190 27MHz high-resolution timer. Its also a workaround for
1191 NSC Geode SC-1100's buggy TSC, which loses time when the
1192 processor goes idle (as is done by the scheduler). The
1193 other workaround is idle=poll boot option.
1197 depends on AGP_AMD64
1199 source "drivers/pcmcia/Kconfig"
1201 source "drivers/pci/hotplug/Kconfig"
1205 menu "Executable file formats"
1207 source "fs/Kconfig.binfmt"
1211 source "net/Kconfig"
1213 source "drivers/Kconfig"
1217 menuconfig INSTRUMENTATION
1218 bool "Instrumentation Support"
1219 depends on EXPERIMENTAL
1224 source "arch/i386/oprofile/Kconfig"
1228 depends on KALLSYMS && MODULES
1230 Kprobes allows you to trap at almost any kernel address and
1231 execute a callback function. register_kprobe() establishes
1232 a probepoint and specifies the callback. Kprobes is useful
1233 for kernel debugging, non-intrusive instrumentation and testing.
1234 If in doubt, say "N".
1236 endif # INSTRUMENTATION
1238 source "arch/i386/Kconfig.debug"
1240 source "security/Kconfig"
1242 source "crypto/Kconfig"
1244 source "lib/Kconfig"
1247 # Use the generic interrupt handling code in kernel/irq/:
1249 config GENERIC_HARDIRQS
1253 config GENERIC_IRQ_PROBE
1257 config GENERIC_PENDING_IRQ
1259 depends on GENERIC_HARDIRQS && SMP
1264 depends on SMP && !X86_VOYAGER
1269 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1272 config X86_BIOS_REBOOT
1274 depends on !(X86_VISWS || X86_VOYAGER)
1277 config X86_TRAMPOLINE
1279 depends on X86_SMP || (X86_VOYAGER && SMP)
projects / linux-2.6 / blob