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 GENERIC_CMOS_UPDATE
25 config CLOCKSOURCE_WATCHDOG
29 config GENERIC_CLOCKEVENTS
33 config GENERIC_CLOCKEVENTS_BROADCAST
36 depends on X86_LOCAL_APIC
38 config LOCKDEP_SUPPORT
42 config STACKTRACE_SUPPORT
46 config SEMAPHORE_SLEEPERS
69 config GENERIC_ISA_DMA
82 config GENERIC_HWEIGHT
86 config ARCH_MAY_HAVE_PC_FDC
96 menu "Processor type and features"
98 source "kernel/time/Kconfig"
101 bool "Symmetric multi-processing support"
103 This enables support for systems with more than one CPU. If you have
104 a system with only one CPU, like most personal computers, say N. If
105 you have a system with more than one CPU, say Y.
107 If you say N here, the kernel will run on single and multiprocessor
108 machines, but will use only one CPU of a multiprocessor machine. If
109 you say Y here, the kernel will run on many, but not all,
110 singleprocessor machines. On a singleprocessor machine, the kernel
111 will run faster if you say N here.
113 Note that if you say Y here and choose architecture "586" or
114 "Pentium" under "Processor family", the kernel will not work on 486
115 architectures. Similarly, multiprocessor kernels for the "PPro"
116 architecture may not work on all Pentium based boards.
118 People using multiprocessor machines who say Y here should also say
119 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
120 Management" code will be disabled if you say Y here.
122 See also the <file:Documentation/smp.txt>,
123 <file:Documentation/i386/IO-APIC.txt>,
124 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
125 <http://www.tldp.org/docs.html#howto>.
127 If you don't know what to do here, say N.
130 prompt "Subarchitecture Type"
136 Choose this option if your computer is a standard PC or compatible.
141 Select this for an AMD Elan processor.
143 Do not use this option for K6/Athlon/Opteron processors!
145 If unsure, choose "PC-compatible" instead.
150 Voyager is an MCA-based 32-way capable SMP architecture proprietary
151 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
155 If you do not specifically know you have a Voyager based machine,
156 say N here, otherwise the kernel you build will not be bootable.
159 bool "NUMAQ (IBM/Sequent)"
163 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
164 multiquad box. This changes the way that processors are bootstrapped,
165 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
166 You will need a new lynxer.elf file to flash your firmware with - send
167 email to <Martin.Bligh@us.ibm.com>.
170 bool "Summit/EXA (IBM x440)"
173 This option is needed for IBM systems that use the Summit/EXA chipset.
174 In particular, it is needed for the x440.
176 If you don't have one of these computers, you should say N here.
177 If you want to build a NUMA kernel, you must select ACPI.
180 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
183 This option is needed for the systems that have more than 8 CPUs
184 and if the system is not of any sub-arch type above.
186 If you don't have such a system, you should say N here.
189 bool "SGI 320/540 (Visual Workstation)"
191 The SGI Visual Workstation series is an IA32-based workstation
192 based on SGI systems chips with some legacy PC hardware attached.
194 Say Y here to create a kernel to run on the SGI 320 or 540.
196 A kernel compiled for the Visual Workstation will not run on PCs
197 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
199 config X86_GENERICARCH
200 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
202 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
203 It is intended for a generic binary kernel.
204 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
207 bool "Support for Unisys ES7000 IA32 series"
210 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
211 supposed to run on an IA32-based Unisys ES7000 system.
212 Only choose this option if you have such a system, otherwise you
218 bool "Paravirtualization support (EXPERIMENTAL)"
219 depends on EXPERIMENTAL
220 depends on !(X86_VISWS || X86_VOYAGER)
222 Paravirtualization is a way of running multiple instances of
223 Linux on the same machine, under a hypervisor. This option
224 changes the kernel so it can modify itself when it is run
225 under a hypervisor, improving performance significantly.
226 However, when run without a hypervisor the kernel is
227 theoretically slower. If in doubt, say N.
229 source "arch/i386/xen/Kconfig"
232 bool "VMI Paravirt-ops support"
235 VMI provides a paravirtualized interface to the VMware ESX server
236 (it could be used by other hypervisors in theory too, but is not
237 at the moment), by linking the kernel to a GPL-ed ROM module
238 provided by the hypervisor.
243 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
246 config HAVE_ARCH_PARSE_SRAT
251 config X86_SUMMIT_NUMA
254 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
256 config X86_CYCLONE_TIMER
259 depends on X86_SUMMIT || X86_GENERICARCH
261 config ES7000_CLUSTERED_APIC
264 depends on SMP && X86_ES7000 && MPENTIUMIII
266 source "arch/i386/Kconfig.cpu"
269 bool "HPET Timer Support"
271 This enables the use of the HPET for the kernel's internal timer.
272 HPET is the next generation timer replacing legacy 8254s.
273 You can safely choose Y here. However, HPET will only be
274 activated if the platform and the BIOS support this feature.
275 Otherwise the 8254 will be used for timing services.
277 Choose N to continue using the legacy 8254 timer.
279 config HPET_EMULATE_RTC
281 depends on HPET_TIMER && RTC=y
285 int "Maximum number of CPUs (2-255)"
288 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
291 This allows you to specify the maximum number of CPUs which this
292 kernel will support. The maximum supported value is 255 and the
293 minimum value which makes sense is 2.
295 This is purely to save memory - each supported CPU adds
296 approximately eight kilobytes to the kernel image.
299 bool "SMT (Hyperthreading) scheduler support"
302 SMT scheduler support improves the CPU scheduler's decision making
303 when dealing with Intel Pentium 4 chips with HyperThreading at a
304 cost of slightly increased overhead in some places. If unsure say
308 bool "Multi-core scheduler support"
312 Multi-core scheduler support improves the CPU scheduler's decision
313 making when dealing with multi-core CPU chips at a cost of slightly
314 increased overhead in some places. If unsure say N here.
316 source "kernel/Kconfig.preempt"
319 bool "Local APIC support on uniprocessors"
320 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
322 A local APIC (Advanced Programmable Interrupt Controller) is an
323 integrated interrupt controller in the CPU. If you have a single-CPU
324 system which has a processor with a local APIC, you can say Y here to
325 enable and use it. If you say Y here even though your machine doesn't
326 have a local APIC, then the kernel will still run with no slowdown at
327 all. The local APIC supports CPU-generated self-interrupts (timer,
328 performance counters), and the NMI watchdog which detects hard
332 bool "IO-APIC support on uniprocessors"
333 depends on X86_UP_APIC
335 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
336 SMP-capable replacement for PC-style interrupt controllers. Most
337 SMP systems and many recent uniprocessor systems have one.
339 If you have a single-CPU system with an IO-APIC, you can say Y here
340 to use it. If you say Y here even though your machine doesn't have
341 an IO-APIC, then the kernel will still run with no slowdown at all.
343 config X86_LOCAL_APIC
345 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
350 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
353 config X86_VISWS_APIC
359 bool "Machine Check Exception"
360 depends on !X86_VOYAGER
362 Machine Check Exception support allows the processor to notify the
363 kernel if it detects a problem (e.g. overheating, component failure).
364 The action the kernel takes depends on the severity of the problem,
365 ranging from a warning message on the console, to halting the machine.
366 Your processor must be a Pentium or newer to support this - check the
367 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
368 have a design flaw which leads to false MCE events - hence MCE is
369 disabled on all P5 processors, unless explicitly enabled with "mce"
370 as a boot argument. Similarly, if MCE is built in and creates a
371 problem on some new non-standard machine, you can boot with "nomce"
372 to disable it. MCE support simply ignores non-MCE processors like
373 the 386 and 486, so nearly everyone can say Y here.
375 config X86_MCE_NONFATAL
376 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
379 Enabling this feature starts a timer that triggers every 5 seconds which
380 will look at the machine check registers to see if anything happened.
381 Non-fatal problems automatically get corrected (but still logged).
382 Disable this if you don't want to see these messages.
383 Seeing the messages this option prints out may be indicative of dying hardware,
384 or out-of-spec (ie, overclocked) hardware.
385 This option only does something on certain CPUs.
386 (AMD Athlon/Duron and Intel Pentium 4)
388 config X86_MCE_P4THERMAL
389 bool "check for P4 thermal throttling interrupt."
390 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
392 Enabling this feature will cause a message to be printed when the P4
393 enters thermal throttling.
397 bool "Enable VM86 support" if EMBEDDED
399 This option is required by programs like DOSEMU to run 16-bit legacy
400 code on X86 processors. It also may be needed by software like
401 XFree86 to initialize some video cards via BIOS. Disabling this
402 option saves about 6k.
405 tristate "Toshiba Laptop support"
407 This adds a driver to safely access the System Management Mode of
408 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
409 not work on models with a Phoenix BIOS. The System Management Mode
410 is used to set the BIOS and power saving options on Toshiba portables.
412 For information on utilities to make use of this driver see the
413 Toshiba Linux utilities web site at:
414 <http://www.buzzard.org.uk/toshiba/>.
416 Say Y if you intend to run this kernel on a Toshiba portable.
420 tristate "Dell laptop support"
422 This adds a driver to safely access the System Management Mode
423 of the CPU on the Dell Inspiron 8000. The System Management Mode
424 is used to read cpu temperature and cooling fan status and to
425 control the fans on the I8K portables.
427 This driver has been tested only on the Inspiron 8000 but it may
428 also work with other Dell laptops. You can force loading on other
429 models by passing the parameter `force=1' to the module. Use at
432 For information on utilities to make use of this driver see the
433 I8K Linux utilities web site at:
434 <http://people.debian.org/~dz/i8k/>
436 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
439 config X86_REBOOTFIXUPS
440 bool "Enable X86 board specific fixups for reboot"
444 This enables chipset and/or board specific fixups to be done
445 in order to get reboot to work correctly. This is only needed on
446 some combinations of hardware and BIOS. The symptom, for which
447 this config is intended, is when reboot ends with a stalled/hung
450 Currently, the only fixup is for the Geode machines using
451 CS5530A and CS5536 chipsets.
453 Say Y if you want to enable the fixup. Currently, it's safe to
454 enable this option even if you don't need it.
458 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
461 If you say Y here and also to "/dev file system support" in the
462 'File systems' section, you will be able to update the microcode on
463 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
464 Pentium III, Pentium 4, Xeon etc. You will obviously need the
465 actual microcode binary data itself which is not shipped with the
468 For latest news and information on obtaining all the required
469 ingredients for this driver, check:
470 <http://www.urbanmyth.org/microcode/>.
472 To compile this driver as a module, choose M here: the
473 module will be called microcode.
475 config MICROCODE_OLD_INTERFACE
481 tristate "/dev/cpu/*/msr - Model-specific register support"
483 This device gives privileged processes access to the x86
484 Model-Specific Registers (MSRs). It is a character device with
485 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
486 MSR accesses are directed to a specific CPU on multi-processor
490 tristate "/dev/cpu/*/cpuid - CPU information support"
492 This device gives processes access to the x86 CPUID instruction to
493 be executed on a specific processor. It is a character device
494 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
497 source "drivers/firmware/Kconfig"
500 prompt "High Memory Support"
501 default HIGHMEM4G if !X86_NUMAQ
502 default HIGHMEM64G if X86_NUMAQ
506 depends on !X86_NUMAQ
508 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
509 However, the address space of 32-bit x86 processors is only 4
510 Gigabytes large. That means that, if you have a large amount of
511 physical memory, not all of it can be "permanently mapped" by the
512 kernel. The physical memory that's not permanently mapped is called
515 If you are compiling a kernel which will never run on a machine with
516 more than 1 Gigabyte total physical RAM, answer "off" here (default
517 choice and suitable for most users). This will result in a "3GB/1GB"
518 split: 3GB are mapped so that each process sees a 3GB virtual memory
519 space and the remaining part of the 4GB virtual memory space is used
520 by the kernel to permanently map as much physical memory as
523 If the machine has between 1 and 4 Gigabytes physical RAM, then
526 If more than 4 Gigabytes is used then answer "64GB" here. This
527 selection turns Intel PAE (Physical Address Extension) mode on.
528 PAE implements 3-level paging on IA32 processors. PAE is fully
529 supported by Linux, PAE mode is implemented on all recent Intel
530 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
531 then the kernel will not boot on CPUs that don't support PAE!
533 The actual amount of total physical memory will either be
534 auto detected or can be forced by using a kernel command line option
535 such as "mem=256M". (Try "man bootparam" or see the documentation of
536 your boot loader (lilo or loadlin) about how to pass options to the
537 kernel at boot time.)
539 If unsure, say "off".
543 depends on !X86_NUMAQ
545 Select this if you have a 32-bit processor and between 1 and 4
546 gigabytes of physical RAM.
550 depends on !M386 && !M486
552 Select this if you have a 32-bit processor and more than 4
553 gigabytes of physical RAM.
558 depends on EXPERIMENTAL
559 prompt "Memory split" if EMBEDDED
562 Select the desired split between kernel and user memory.
564 If the address range available to the kernel is less than the
565 physical memory installed, the remaining memory will be available
566 as "high memory". Accessing high memory is a little more costly
567 than low memory, as it needs to be mapped into the kernel first.
568 Note that increasing the kernel address space limits the range
569 available to user programs, making the address space there
570 tighter. Selecting anything other than the default 3G/1G split
571 will also likely make your kernel incompatible with binary-only
574 If you are not absolutely sure what you are doing, leave this
578 bool "3G/1G user/kernel split"
579 config VMSPLIT_3G_OPT
581 bool "3G/1G user/kernel split (for full 1G low memory)"
583 bool "2G/2G user/kernel split"
584 config VMSPLIT_2G_OPT
586 bool "2G/2G user/kernel split (for full 2G low memory)"
588 bool "1G/3G user/kernel split"
593 default 0xB0000000 if VMSPLIT_3G_OPT
594 default 0x80000000 if VMSPLIT_2G
595 default 0x78000000 if VMSPLIT_2G_OPT
596 default 0x40000000 if VMSPLIT_1G
601 depends on HIGHMEM64G || HIGHMEM4G
606 depends on HIGHMEM64G
608 select RESOURCES_64BIT
610 # Common NUMA Features
612 bool "Numa Memory Allocation and Scheduler Support"
613 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
615 default y if (X86_NUMAQ || X86_SUMMIT)
617 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
618 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
622 default "4" if X86_NUMAQ
624 depends on NEED_MULTIPLE_NODES
626 config HAVE_ARCH_BOOTMEM_NODE
631 config ARCH_HAVE_MEMORY_PRESENT
633 depends on DISCONTIGMEM
636 config NEED_NODE_MEMMAP_SIZE
638 depends on DISCONTIGMEM || SPARSEMEM
641 config HAVE_ARCH_ALLOC_REMAP
646 config ARCH_FLATMEM_ENABLE
648 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
650 config ARCH_DISCONTIGMEM_ENABLE
654 config ARCH_DISCONTIGMEM_DEFAULT
658 config ARCH_SPARSEMEM_ENABLE
660 depends on (NUMA || (X86_PC && EXPERIMENTAL))
661 select SPARSEMEM_STATIC
663 config ARCH_SELECT_MEMORY_MODEL
665 depends on ARCH_SPARSEMEM_ENABLE
667 config ARCH_POPULATES_NODE_MAP
673 bool "Allocate 3rd-level pagetables from highmem"
674 depends on HIGHMEM4G || HIGHMEM64G
676 The VM uses one page table entry for each page of physical memory.
677 For systems with a lot of RAM, this can be wasteful of precious
678 low memory. Setting this option will put user-space page table
679 entries in high memory.
681 config MATH_EMULATION
682 bool "Math emulation"
684 Linux can emulate a math coprocessor (used for floating point
685 operations) if you don't have one. 486DX and Pentium processors have
686 a math coprocessor built in, 486SX and 386 do not, unless you added
687 a 487DX or 387, respectively. (The messages during boot time can
688 give you some hints here ["man dmesg"].) Everyone needs either a
689 coprocessor or this emulation.
691 If you don't have a math coprocessor, you need to say Y here; if you
692 say Y here even though you have a coprocessor, the coprocessor will
693 be used nevertheless. (This behavior can be changed with the kernel
694 command line option "no387", which comes handy if your coprocessor
695 is broken. Try "man bootparam" or see the documentation of your boot
696 loader (lilo or loadlin) about how to pass options to the kernel at
697 boot time.) This means that it is a good idea to say Y here if you
698 intend to use this kernel on different machines.
700 More information about the internals of the Linux math coprocessor
701 emulation can be found in <file:arch/i386/math-emu/README>.
703 If you are not sure, say Y; apart from resulting in a 66 KB bigger
704 kernel, it won't hurt.
707 bool "MTRR (Memory Type Range Register) support"
709 On Intel P6 family processors (Pentium Pro, Pentium II and later)
710 the Memory Type Range Registers (MTRRs) may be used to control
711 processor access to memory ranges. This is most useful if you have
712 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
713 allows bus write transfers to be combined into a larger transfer
714 before bursting over the PCI/AGP bus. This can increase performance
715 of image write operations 2.5 times or more. Saying Y here creates a
716 /proc/mtrr file which may be used to manipulate your processor's
717 MTRRs. Typically the X server should use this.
719 This code has a reasonably generic interface so that similar
720 control registers on other processors can be easily supported
723 The Cyrix 6x86, 6x86MX and M II processors have Address Range
724 Registers (ARRs) which provide a similar functionality to MTRRs. For
725 these, the ARRs are used to emulate the MTRRs.
726 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
727 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
728 write-combining. All of these processors are supported by this code
729 and it makes sense to say Y here if you have one of them.
731 Saying Y here also fixes a problem with buggy SMP BIOSes which only
732 set the MTRRs for the boot CPU and not for the secondary CPUs. This
733 can lead to all sorts of problems, so it's good to say Y here.
735 You can safely say Y even if your machine doesn't have MTRRs, you'll
736 just add about 9 KB to your kernel.
738 See <file:Documentation/mtrr.txt> for more information.
741 bool "Boot from EFI support"
745 This enables the kernel to boot on EFI platforms using
746 system configuration information passed to it from the firmware.
747 This also enables the kernel to use any EFI runtime services that are
748 available (such as the EFI variable services).
750 This option is only useful on systems that have EFI firmware
751 and will result in a kernel image that is ~8k larger. In addition,
752 you must use the latest ELILO loader available at
753 <http://elilo.sourceforge.net> in order to take advantage of
754 kernel initialization using EFI information (neither GRUB nor LILO know
755 anything about EFI). However, even with this option, the resultant
756 kernel should continue to boot on existing non-EFI platforms.
759 bool "Enable kernel irq balancing"
760 depends on SMP && X86_IO_APIC
763 The default yes will allow the kernel to do irq load balancing.
764 Saying no will keep the kernel from doing irq load balancing.
766 # turning this on wastes a bunch of space.
767 # Summit needs it only when NUMA is on
770 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
774 bool "Enable seccomp to safely compute untrusted bytecode"
778 This kernel feature is useful for number crunching applications
779 that may need to compute untrusted bytecode during their
780 execution. By using pipes or other transports made available to
781 the process as file descriptors supporting the read/write
782 syscalls, it's possible to isolate those applications in
783 their own address space using seccomp. Once seccomp is
784 enabled via /proc/<pid>/seccomp, it cannot be disabled
785 and the task is only allowed to execute a few safe syscalls
786 defined by each seccomp mode.
788 If unsure, say Y. Only embedded should say N here.
790 source kernel/Kconfig.hz
793 bool "kexec system call"
795 kexec is a system call that implements the ability to shutdown your
796 current kernel, and to start another kernel. It is like a reboot
797 but it is independent of the system firmware. And like a reboot
798 you can start any kernel with it, not just Linux.
800 The name comes from the similarity to the exec system call.
802 It is an ongoing process to be certain the hardware in a machine
803 is properly shutdown, so do not be surprised if this code does not
804 initially work for you. It may help to enable device hotplugging
805 support. As of this writing the exact hardware interface is
806 strongly in flux, so no good recommendation can be made.
809 bool "kernel crash dumps (EXPERIMENTAL)"
810 depends on EXPERIMENTAL
813 Generate crash dump after being started by kexec.
814 This should be normally only set in special crash dump kernels
815 which are loaded in the main kernel with kexec-tools into
816 a specially reserved region and then later executed after
817 a crash by kdump/kexec. The crash dump kernel must be compiled
818 to a memory address not used by the main kernel or BIOS using
820 For more details see Documentation/kdump/kdump.txt
822 config PHYSICAL_START
823 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
826 This gives the physical address where the kernel is loaded.
828 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
829 bzImage will decompress itself to above physical address and
830 run from there. Otherwise, bzImage will run from the address where
831 it has been loaded by the boot loader and will ignore above physical
834 In normal kdump cases one does not have to set/change this option
835 as now bzImage can be compiled as a completely relocatable image
836 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
837 address. This option is mainly useful for the folks who don't want
838 to use a bzImage for capturing the crash dump and want to use a
839 vmlinux instead. vmlinux is not relocatable hence a kernel needs
840 to be specifically compiled to run from a specific memory area
841 (normally a reserved region) and this option comes handy.
843 So if you are using bzImage for capturing the crash dump, leave
844 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
845 Otherwise if you plan to use vmlinux for capturing the crash dump
846 change this value to start of the reserved region (Typically 16MB
847 0x1000000). In other words, it can be set based on the "X" value as
848 specified in the "crashkernel=YM@XM" command line boot parameter
849 passed to the panic-ed kernel. Typically this parameter is set as
850 crashkernel=64M@16M. Please take a look at
851 Documentation/kdump/kdump.txt for more details about crash dumps.
853 Usage of bzImage for capturing the crash dump is recommended as
854 one does not have to build two kernels. Same kernel can be used
855 as production kernel and capture kernel. Above option should have
856 gone away after relocatable bzImage support is introduced. But it
857 is present because there are users out there who continue to use
858 vmlinux for dump capture. This option should go away down the
861 Don't change this unless you know what you are doing.
864 bool "Build a relocatable kernel(EXPERIMENTAL)"
865 depends on EXPERIMENTAL
867 This builds a kernel image that retains relocation information
868 so it can be loaded someplace besides the default 1MB.
869 The relocations tend to make the kernel binary about 10% larger,
870 but are discarded at runtime.
872 One use is for the kexec on panic case where the recovery kernel
873 must live at a different physical address than the primary
876 config PHYSICAL_ALIGN
877 hex "Alignment value to which kernel should be aligned"
879 range 0x2000 0x400000
881 This value puts the alignment restrictions on physical address
882 where kernel is loaded and run from. Kernel is compiled for an
883 address which meets above alignment restriction.
885 If bootloader loads the kernel at a non-aligned address and
886 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
887 address aligned to above value and run from there.
889 If bootloader loads the kernel at a non-aligned address and
890 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
891 load address and decompress itself to the address it has been
892 compiled for and run from there. The address for which kernel is
893 compiled already meets above alignment restrictions. Hence the
894 end result is that kernel runs from a physical address meeting
895 above alignment restrictions.
897 Don't change this unless you know what you are doing.
900 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
901 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
903 Say Y here to experiment with turning CPUs off and on, and to
904 enable suspend on SMP systems. CPUs can be controlled through
905 /sys/devices/system/cpu.
908 bool "Compat VDSO support"
911 Map the VDSO to the predictable old-style address too.
913 Say N here if you are running a sufficiently recent glibc
914 version (2.3.3 or later), to remove the high-mapped
915 VDSO mapping and to exclusively use the randomized VDSO.
921 config ARCH_ENABLE_MEMORY_HOTPLUG
925 menu "Power management options (ACPI, APM)"
926 depends on !X86_VOYAGER
928 source kernel/power/Kconfig
930 source "drivers/acpi/Kconfig"
933 tristate "APM (Advanced Power Management) BIOS support"
934 depends on PM && !X86_VISWS
936 APM is a BIOS specification for saving power using several different
937 techniques. This is mostly useful for battery powered laptops with
938 APM compliant BIOSes. If you say Y here, the system time will be
939 reset after a RESUME operation, the /proc/apm device will provide
940 battery status information, and user-space programs will receive
941 notification of APM "events" (e.g. battery status change).
943 If you select "Y" here, you can disable actual use of the APM
944 BIOS by passing the "apm=off" option to the kernel at boot time.
946 Note that the APM support is almost completely disabled for
947 machines with more than one CPU.
949 In order to use APM, you will need supporting software. For location
950 and more information, read <file:Documentation/pm.txt> and the
951 Battery Powered Linux mini-HOWTO, available from
952 <http://www.tldp.org/docs.html#howto>.
954 This driver does not spin down disk drives (see the hdparm(8)
955 manpage ("man 8 hdparm") for that), and it doesn't turn off
956 VESA-compliant "green" monitors.
958 This driver does not support the TI 4000M TravelMate and the ACER
959 486/DX4/75 because they don't have compliant BIOSes. Many "green"
960 desktop machines also don't have compliant BIOSes, and this driver
961 may cause those machines to panic during the boot phase.
963 Generally, if you don't have a battery in your machine, there isn't
964 much point in using this driver and you should say N. If you get
965 random kernel OOPSes or reboots that don't seem to be related to
966 anything, try disabling/enabling this option (or disabling/enabling
969 Some other things you should try when experiencing seemingly random,
972 1) make sure that you have enough swap space and that it is
974 2) pass the "no-hlt" option to the kernel
975 3) switch on floating point emulation in the kernel and pass
976 the "no387" option to the kernel
977 4) pass the "floppy=nodma" option to the kernel
978 5) pass the "mem=4M" option to the kernel (thereby disabling
979 all but the first 4 MB of RAM)
980 6) make sure that the CPU is not over clocked.
981 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
982 8) disable the cache from your BIOS settings
983 9) install a fan for the video card or exchange video RAM
984 10) install a better fan for the CPU
985 11) exchange RAM chips
986 12) exchange the motherboard.
988 To compile this driver as a module, choose M here: the
989 module will be called apm.
993 config APM_IGNORE_USER_SUSPEND
994 bool "Ignore USER SUSPEND"
996 This option will ignore USER SUSPEND requests. On machines with a
997 compliant APM BIOS, you want to say N. However, on the NEC Versa M
998 series notebooks, it is necessary to say Y because of a BIOS bug.
1000 config APM_DO_ENABLE
1001 bool "Enable PM at boot time"
1003 Enable APM features at boot time. From page 36 of the APM BIOS
1004 specification: "When disabled, the APM BIOS does not automatically
1005 power manage devices, enter the Standby State, enter the Suspend
1006 State, or take power saving steps in response to CPU Idle calls."
1007 This driver will make CPU Idle calls when Linux is idle (unless this
1008 feature is turned off -- see "Do CPU IDLE calls", below). This
1009 should always save battery power, but more complicated APM features
1010 will be dependent on your BIOS implementation. You may need to turn
1011 this option off if your computer hangs at boot time when using APM
1012 support, or if it beeps continuously instead of suspending. Turn
1013 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1014 T400CDT. This is off by default since most machines do fine without
1018 bool "Make CPU Idle calls when idle"
1020 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1021 On some machines, this can activate improved power savings, such as
1022 a slowed CPU clock rate, when the machine is idle. These idle calls
1023 are made after the idle loop has run for some length of time (e.g.,
1024 333 mS). On some machines, this will cause a hang at boot time or
1025 whenever the CPU becomes idle. (On machines with more than one CPU,
1026 this option does nothing.)
1028 config APM_DISPLAY_BLANK
1029 bool "Enable console blanking using APM"
1031 Enable console blanking using the APM. Some laptops can use this to
1032 turn off the LCD backlight when the screen blanker of the Linux
1033 virtual console blanks the screen. Note that this is only used by
1034 the virtual console screen blanker, and won't turn off the backlight
1035 when using the X Window system. This also doesn't have anything to
1036 do with your VESA-compliant power-saving monitor. Further, this
1037 option doesn't work for all laptops -- it might not turn off your
1038 backlight at all, or it might print a lot of errors to the console,
1039 especially if you are using gpm.
1041 config APM_ALLOW_INTS
1042 bool "Allow interrupts during APM BIOS calls"
1044 Normally we disable external interrupts while we are making calls to
1045 the APM BIOS as a measure to lessen the effects of a badly behaving
1046 BIOS implementation. The BIOS should reenable interrupts if it
1047 needs to. Unfortunately, some BIOSes do not -- especially those in
1048 many of the newer IBM Thinkpads. If you experience hangs when you
1049 suspend, try setting this to Y. Otherwise, say N.
1051 config APM_REAL_MODE_POWER_OFF
1052 bool "Use real mode APM BIOS call to power off"
1054 Use real mode APM BIOS calls to switch off the computer. This is
1055 a work-around for a number of buggy BIOSes. Switch this option on if
1056 your computer crashes instead of powering off properly.
1060 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1064 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1067 bool "PCI support" if !X86_VISWS
1068 depends on !X86_VOYAGER
1069 default y if X86_VISWS
1070 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1072 Find out whether you have a PCI motherboard. PCI is the name of a
1073 bus system, i.e. the way the CPU talks to the other stuff inside
1074 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1075 VESA. If you have PCI, say Y, otherwise N.
1077 The PCI-HOWTO, available from
1078 <http://www.tldp.org/docs.html#howto>, contains valuable
1079 information about which PCI hardware does work under Linux and which
1083 prompt "PCI access mode"
1084 depends on PCI && !X86_VISWS
1087 On PCI systems, the BIOS can be used to detect the PCI devices and
1088 determine their configuration. However, some old PCI motherboards
1089 have BIOS bugs and may crash if this is done. Also, some embedded
1090 PCI-based systems don't have any BIOS at all. Linux can also try to
1091 detect the PCI hardware directly without using the BIOS.
1093 With this option, you can specify how Linux should detect the
1094 PCI devices. If you choose "BIOS", the BIOS will be used,
1095 if you choose "Direct", the BIOS won't be used, and if you
1096 choose "MMConfig", then PCI Express MMCONFIG will be used.
1097 If you choose "Any", the kernel will try MMCONFIG, then the
1098 direct access method and falls back to the BIOS if that doesn't
1099 work. If unsure, go with the default, which is "Any".
1104 config PCI_GOMMCONFIG
1117 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1122 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1127 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1130 source "drivers/pci/pcie/Kconfig"
1132 source "drivers/pci/Kconfig"
1140 depends on !(X86_VOYAGER || X86_VISWS)
1142 Find out whether you have ISA slots on your motherboard. ISA is the
1143 name of a bus system, i.e. the way the CPU talks to the other stuff
1144 inside your box. Other bus systems are PCI, EISA, MicroChannel
1145 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1146 newer boards don't support it. If you have ISA, say Y, otherwise N.
1152 The Extended Industry Standard Architecture (EISA) bus was
1153 developed as an open alternative to the IBM MicroChannel bus.
1155 The EISA bus provided some of the features of the IBM MicroChannel
1156 bus while maintaining backward compatibility with cards made for
1157 the older ISA bus. The EISA bus saw limited use between 1988 and
1158 1995 when it was made obsolete by the PCI bus.
1160 Say Y here if you are building a kernel for an EISA-based machine.
1164 source "drivers/eisa/Kconfig"
1167 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1168 default y if X86_VOYAGER
1170 MicroChannel Architecture is found in some IBM PS/2 machines and
1171 laptops. It is a bus system similar to PCI or ISA. See
1172 <file:Documentation/mca.txt> (and especially the web page given
1173 there) before attempting to build an MCA bus kernel.
1175 source "drivers/mca/Kconfig"
1178 tristate "NatSemi SCx200 support"
1179 depends on !X86_VOYAGER
1181 This provides basic support for National Semiconductor's
1182 (now AMD's) Geode processors. The driver probes for the
1183 PCI-IDs of several on-chip devices, so its a good dependency
1184 for other scx200_* drivers.
1186 If compiled as a module, the driver is named scx200.
1188 config SCx200HR_TIMER
1189 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1190 depends on SCx200 && GENERIC_TIME
1193 This driver provides a clocksource built upon the on-chip
1194 27MHz high-resolution timer. Its also a workaround for
1195 NSC Geode SC-1100's buggy TSC, which loses time when the
1196 processor goes idle (as is done by the scheduler). The
1197 other workaround is idle=poll boot option.
1201 depends on AGP_AMD64
1203 source "drivers/pcmcia/Kconfig"
1205 source "drivers/pci/hotplug/Kconfig"
1209 menu "Executable file formats"
1211 source "fs/Kconfig.binfmt"
1215 source "net/Kconfig"
1217 source "drivers/Kconfig"
1221 menuconfig INSTRUMENTATION
1222 bool "Instrumentation Support"
1223 depends on EXPERIMENTAL
1228 source "arch/i386/oprofile/Kconfig"
1232 depends on KALLSYMS && MODULES
1234 Kprobes allows you to trap at almost any kernel address and
1235 execute a callback function. register_kprobe() establishes
1236 a probepoint and specifies the callback. Kprobes is useful
1237 for kernel debugging, non-intrusive instrumentation and testing.
1238 If in doubt, say "N".
1240 endif # INSTRUMENTATION
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)
projects / linux-2.6 / blob