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
61 config GENERIC_ISA_DMA
74 config GENERIC_HWEIGHT
78 config ARCH_MAY_HAVE_PC_FDC
88 menu "Processor type and features"
90 source "kernel/time/Kconfig"
93 bool "Symmetric multi-processing support"
95 This enables support for systems with more than one CPU. If you have
96 a system with only one CPU, like most personal computers, say N. If
97 you have a system with more than one CPU, say Y.
99 If you say N here, the kernel will run on single and multiprocessor
100 machines, but will use only one CPU of a multiprocessor machine. If
101 you say Y here, the kernel will run on many, but not all,
102 singleprocessor machines. On a singleprocessor machine, the kernel
103 will run faster if you say N here.
105 Note that if you say Y here and choose architecture "586" or
106 "Pentium" under "Processor family", the kernel will not work on 486
107 architectures. Similarly, multiprocessor kernels for the "PPro"
108 architecture may not work on all Pentium based boards.
110 People using multiprocessor machines who say Y here should also say
111 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
112 Management" code will be disabled if you say Y here.
114 See also the <file:Documentation/smp.txt>,
115 <file:Documentation/i386/IO-APIC.txt>,
116 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
117 <http://www.tldp.org/docs.html#howto>.
119 If you don't know what to do here, say N.
122 prompt "Subarchitecture Type"
128 Choose this option if your computer is a standard PC or compatible.
133 Select this for an AMD Elan processor.
135 Do not use this option for K6/Athlon/Opteron processors!
137 If unsure, choose "PC-compatible" instead.
142 Voyager is an MCA-based 32-way capable SMP architecture proprietary
143 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
147 If you do not specifically know you have a Voyager based machine,
148 say N here, otherwise the kernel you build will not be bootable.
151 bool "NUMAQ (IBM/Sequent)"
155 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
156 multiquad box. This changes the way that processors are bootstrapped,
157 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
158 You will need a new lynxer.elf file to flash your firmware with - send
159 email to <Martin.Bligh@us.ibm.com>.
162 bool "Summit/EXA (IBM x440)"
165 This option is needed for IBM systems that use the Summit/EXA chipset.
166 In particular, it is needed for the x440.
168 If you don't have one of these computers, you should say N here.
169 If you want to build a NUMA kernel, you must select ACPI.
172 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
175 This option is needed for the systems that have more than 8 CPUs
176 and if the system is not of any sub-arch type above.
178 If you don't have such a system, you should say N here.
181 bool "SGI 320/540 (Visual Workstation)"
183 The SGI Visual Workstation series is an IA32-based workstation
184 based on SGI systems chips with some legacy PC hardware attached.
186 Say Y here to create a kernel to run on the SGI 320 or 540.
188 A kernel compiled for the Visual Workstation will not run on PCs
189 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
191 config X86_GENERICARCH
192 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
194 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
195 It is intended for a generic binary kernel.
196 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
199 bool "Support for Unisys ES7000 IA32 series"
202 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
203 supposed to run on an IA32-based Unisys ES7000 system.
204 Only choose this option if you have such a system, otherwise you
210 bool "Paravirtualization support (EXPERIMENTAL)"
211 depends on EXPERIMENTAL
212 depends on !(X86_VISWS || X86_VOYAGER)
214 Paravirtualization is a way of running multiple instances of
215 Linux on the same machine, under a hypervisor. This option
216 changes the kernel so it can modify itself when it is run
217 under a hypervisor, improving performance significantly.
218 However, when run without a hypervisor the kernel is
219 theoretically slower. If in doubt, say N.
222 bool "VMI Paravirt-ops support"
225 VMI provides a paravirtualized interface to the VMware ESX server
226 (it could be used by other hypervisors in theory too, but is not
227 at the moment), by linking the kernel to a GPL-ed ROM module
228 provided by the hypervisor.
233 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
236 config HAVE_ARCH_PARSE_SRAT
241 config X86_SUMMIT_NUMA
244 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
246 config X86_CYCLONE_TIMER
249 depends on X86_SUMMIT || X86_GENERICARCH
251 config ES7000_CLUSTERED_APIC
254 depends on SMP && X86_ES7000 && MPENTIUMIII
256 source "arch/i386/Kconfig.cpu"
259 bool "HPET Timer Support"
261 This enables the use of the HPET for the kernel's internal timer.
262 HPET is the next generation timer replacing legacy 8254s.
263 You can safely choose Y here. However, HPET will only be
264 activated if the platform and the BIOS support this feature.
265 Otherwise the 8254 will be used for timing services.
267 Choose N to continue using the legacy 8254 timer.
269 config HPET_EMULATE_RTC
271 depends on HPET_TIMER && RTC=y
275 int "Maximum number of CPUs (2-255)"
278 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
281 This allows you to specify the maximum number of CPUs which this
282 kernel will support. The maximum supported value is 255 and the
283 minimum value which makes sense is 2.
285 This is purely to save memory - each supported CPU adds
286 approximately eight kilobytes to the kernel image.
289 bool "SMT (Hyperthreading) scheduler support"
292 SMT scheduler support improves the CPU scheduler's decision making
293 when dealing with Intel Pentium 4 chips with HyperThreading at a
294 cost of slightly increased overhead in some places. If unsure say
298 bool "Multi-core scheduler support"
302 Multi-core scheduler support improves the CPU scheduler's decision
303 making when dealing with multi-core CPU chips at a cost of slightly
304 increased overhead in some places. If unsure say N here.
306 source "kernel/Kconfig.preempt"
309 bool "Local APIC support on uniprocessors"
310 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
312 A local APIC (Advanced Programmable Interrupt Controller) is an
313 integrated interrupt controller in the CPU. If you have a single-CPU
314 system which has a processor with a local APIC, you can say Y here to
315 enable and use it. If you say Y here even though your machine doesn't
316 have a local APIC, then the kernel will still run with no slowdown at
317 all. The local APIC supports CPU-generated self-interrupts (timer,
318 performance counters), and the NMI watchdog which detects hard
322 bool "IO-APIC support on uniprocessors"
323 depends on X86_UP_APIC
325 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
326 SMP-capable replacement for PC-style interrupt controllers. Most
327 SMP systems and many recent uniprocessor systems have one.
329 If you have a single-CPU system with an IO-APIC, you can say Y here
330 to use it. If you say Y here even though your machine doesn't have
331 an IO-APIC, then the kernel will still run with no slowdown at all.
333 config X86_LOCAL_APIC
335 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
340 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
343 config X86_VISWS_APIC
349 bool "Machine Check Exception"
350 depends on !X86_VOYAGER
352 Machine Check Exception support allows the processor to notify the
353 kernel if it detects a problem (e.g. overheating, component failure).
354 The action the kernel takes depends on the severity of the problem,
355 ranging from a warning message on the console, to halting the machine.
356 Your processor must be a Pentium or newer to support this - check the
357 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
358 have a design flaw which leads to false MCE events - hence MCE is
359 disabled on all P5 processors, unless explicitly enabled with "mce"
360 as a boot argument. Similarly, if MCE is built in and creates a
361 problem on some new non-standard machine, you can boot with "nomce"
362 to disable it. MCE support simply ignores non-MCE processors like
363 the 386 and 486, so nearly everyone can say Y here.
365 config X86_MCE_NONFATAL
366 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
369 Enabling this feature starts a timer that triggers every 5 seconds which
370 will look at the machine check registers to see if anything happened.
371 Non-fatal problems automatically get corrected (but still logged).
372 Disable this if you don't want to see these messages.
373 Seeing the messages this option prints out may be indicative of dying hardware,
374 or out-of-spec (ie, overclocked) hardware.
375 This option only does something on certain CPUs.
376 (AMD Athlon/Duron and Intel Pentium 4)
378 config X86_MCE_P4THERMAL
379 bool "check for P4 thermal throttling interrupt."
380 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
382 Enabling this feature will cause a message to be printed when the P4
383 enters thermal throttling.
387 bool "Enable VM86 support" if EMBEDDED
389 This option is required by programs like DOSEMU to run 16-bit legacy
390 code on X86 processors. It also may be needed by software like
391 XFree86 to initialize some video cards via BIOS. Disabling this
392 option saves about 6k.
395 tristate "Toshiba Laptop support"
397 This adds a driver to safely access the System Management Mode of
398 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
399 not work on models with a Phoenix BIOS. The System Management Mode
400 is used to set the BIOS and power saving options on Toshiba portables.
402 For information on utilities to make use of this driver see the
403 Toshiba Linux utilities web site at:
404 <http://www.buzzard.org.uk/toshiba/>.
406 Say Y if you intend to run this kernel on a Toshiba portable.
410 tristate "Dell laptop support"
412 This adds a driver to safely access the System Management Mode
413 of the CPU on the Dell Inspiron 8000. The System Management Mode
414 is used to read cpu temperature and cooling fan status and to
415 control the fans on the I8K portables.
417 This driver has been tested only on the Inspiron 8000 but it may
418 also work with other Dell laptops. You can force loading on other
419 models by passing the parameter `force=1' to the module. Use at
422 For information on utilities to make use of this driver see the
423 I8K Linux utilities web site at:
424 <http://people.debian.org/~dz/i8k/>
426 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
429 config X86_REBOOTFIXUPS
430 bool "Enable X86 board specific fixups for reboot"
434 This enables chipset and/or board specific fixups to be done
435 in order to get reboot to work correctly. This is only needed on
436 some combinations of hardware and BIOS. The symptom, for which
437 this config is intended, is when reboot ends with a stalled/hung
440 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
443 Say Y if you want to enable the fixup. Currently, it's safe to
444 enable this option even if you don't need it.
448 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
451 If you say Y here and also to "/dev file system support" in the
452 'File systems' section, you will be able to update the microcode on
453 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
454 Pentium III, Pentium 4, Xeon etc. You will obviously need the
455 actual microcode binary data itself which is not shipped with the
458 For latest news and information on obtaining all the required
459 ingredients for this driver, check:
460 <http://www.urbanmyth.org/microcode/>.
462 To compile this driver as a module, choose M here: the
463 module will be called microcode.
465 config MICROCODE_OLD_INTERFACE
471 tristate "/dev/cpu/*/msr - Model-specific register support"
473 This device gives privileged processes access to the x86
474 Model-Specific Registers (MSRs). It is a character device with
475 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
476 MSR accesses are directed to a specific CPU on multi-processor
480 tristate "/dev/cpu/*/cpuid - CPU information support"
482 This device gives processes access to the x86 CPUID instruction to
483 be executed on a specific processor. It is a character device
484 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
487 source "drivers/firmware/Kconfig"
490 prompt "High Memory Support"
491 default HIGHMEM4G if !X86_NUMAQ
492 default HIGHMEM64G if X86_NUMAQ
496 depends on !X86_NUMAQ
498 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
499 However, the address space of 32-bit x86 processors is only 4
500 Gigabytes large. That means that, if you have a large amount of
501 physical memory, not all of it can be "permanently mapped" by the
502 kernel. The physical memory that's not permanently mapped is called
505 If you are compiling a kernel which will never run on a machine with
506 more than 1 Gigabyte total physical RAM, answer "off" here (default
507 choice and suitable for most users). This will result in a "3GB/1GB"
508 split: 3GB are mapped so that each process sees a 3GB virtual memory
509 space and the remaining part of the 4GB virtual memory space is used
510 by the kernel to permanently map as much physical memory as
513 If the machine has between 1 and 4 Gigabytes physical RAM, then
516 If more than 4 Gigabytes is used then answer "64GB" here. This
517 selection turns Intel PAE (Physical Address Extension) mode on.
518 PAE implements 3-level paging on IA32 processors. PAE is fully
519 supported by Linux, PAE mode is implemented on all recent Intel
520 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
521 then the kernel will not boot on CPUs that don't support PAE!
523 The actual amount of total physical memory will either be
524 auto detected or can be forced by using a kernel command line option
525 such as "mem=256M". (Try "man bootparam" or see the documentation of
526 your boot loader (lilo or loadlin) about how to pass options to the
527 kernel at boot time.)
529 If unsure, say "off".
533 depends on !X86_NUMAQ
535 Select this if you have a 32-bit processor and between 1 and 4
536 gigabytes of physical RAM.
540 depends on X86_CMPXCHG64
542 Select this if you have a 32-bit processor and more than 4
543 gigabytes of physical RAM.
548 depends on EXPERIMENTAL
549 prompt "Memory split" if EMBEDDED
552 Select the desired split between kernel and user memory.
554 If the address range available to the kernel is less than the
555 physical memory installed, the remaining memory will be available
556 as "high memory". Accessing high memory is a little more costly
557 than low memory, as it needs to be mapped into the kernel first.
558 Note that increasing the kernel address space limits the range
559 available to user programs, making the address space there
560 tighter. Selecting anything other than the default 3G/1G split
561 will also likely make your kernel incompatible with binary-only
564 If you are not absolutely sure what you are doing, leave this
568 bool "3G/1G user/kernel split"
569 config VMSPLIT_3G_OPT
571 bool "3G/1G user/kernel split (for full 1G low memory)"
573 bool "2G/2G user/kernel split"
574 config VMSPLIT_2G_OPT
576 bool "2G/2G user/kernel split (for full 2G low memory)"
578 bool "1G/3G user/kernel split"
583 default 0xB0000000 if VMSPLIT_3G_OPT
584 default 0x80000000 if VMSPLIT_2G
585 default 0x78000000 if VMSPLIT_2G_OPT
586 default 0x40000000 if VMSPLIT_1G
591 depends on HIGHMEM64G || HIGHMEM4G
596 depends on HIGHMEM64G
598 select RESOURCES_64BIT
600 # Common NUMA Features
602 bool "Numa Memory Allocation and Scheduler Support"
603 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
605 default y if (X86_NUMAQ || X86_SUMMIT)
607 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
608 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
612 default "4" if X86_NUMAQ
614 depends on NEED_MULTIPLE_NODES
616 config HAVE_ARCH_BOOTMEM_NODE
621 config ARCH_HAVE_MEMORY_PRESENT
623 depends on DISCONTIGMEM
626 config NEED_NODE_MEMMAP_SIZE
628 depends on DISCONTIGMEM || SPARSEMEM
631 config HAVE_ARCH_ALLOC_REMAP
636 config ARCH_FLATMEM_ENABLE
638 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
640 config ARCH_DISCONTIGMEM_ENABLE
644 config ARCH_DISCONTIGMEM_DEFAULT
648 config ARCH_SPARSEMEM_ENABLE
650 depends on (NUMA || (X86_PC && EXPERIMENTAL))
651 select SPARSEMEM_STATIC
653 config ARCH_SELECT_MEMORY_MODEL
655 depends on ARCH_SPARSEMEM_ENABLE
657 config ARCH_POPULATES_NODE_MAP
663 bool "Allocate 3rd-level pagetables from highmem"
664 depends on HIGHMEM4G || HIGHMEM64G
666 The VM uses one page table entry for each page of physical memory.
667 For systems with a lot of RAM, this can be wasteful of precious
668 low memory. Setting this option will put user-space page table
669 entries in high memory.
671 config MATH_EMULATION
672 bool "Math emulation"
674 Linux can emulate a math coprocessor (used for floating point
675 operations) if you don't have one. 486DX and Pentium processors have
676 a math coprocessor built in, 486SX and 386 do not, unless you added
677 a 487DX or 387, respectively. (The messages during boot time can
678 give you some hints here ["man dmesg"].) Everyone needs either a
679 coprocessor or this emulation.
681 If you don't have a math coprocessor, you need to say Y here; if you
682 say Y here even though you have a coprocessor, the coprocessor will
683 be used nevertheless. (This behavior can be changed with the kernel
684 command line option "no387", which comes handy if your coprocessor
685 is broken. Try "man bootparam" or see the documentation of your boot
686 loader (lilo or loadlin) about how to pass options to the kernel at
687 boot time.) This means that it is a good idea to say Y here if you
688 intend to use this kernel on different machines.
690 More information about the internals of the Linux math coprocessor
691 emulation can be found in <file:arch/i386/math-emu/README>.
693 If you are not sure, say Y; apart from resulting in a 66 KB bigger
694 kernel, it won't hurt.
697 bool "MTRR (Memory Type Range Register) support"
699 On Intel P6 family processors (Pentium Pro, Pentium II and later)
700 the Memory Type Range Registers (MTRRs) may be used to control
701 processor access to memory ranges. This is most useful if you have
702 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
703 allows bus write transfers to be combined into a larger transfer
704 before bursting over the PCI/AGP bus. This can increase performance
705 of image write operations 2.5 times or more. Saying Y here creates a
706 /proc/mtrr file which may be used to manipulate your processor's
707 MTRRs. Typically the X server should use this.
709 This code has a reasonably generic interface so that similar
710 control registers on other processors can be easily supported
713 The Cyrix 6x86, 6x86MX and M II processors have Address Range
714 Registers (ARRs) which provide a similar functionality to MTRRs. For
715 these, the ARRs are used to emulate the MTRRs.
716 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
717 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
718 write-combining. All of these processors are supported by this code
719 and it makes sense to say Y here if you have one of them.
721 Saying Y here also fixes a problem with buggy SMP BIOSes which only
722 set the MTRRs for the boot CPU and not for the secondary CPUs. This
723 can lead to all sorts of problems, so it's good to say Y here.
725 You can safely say Y even if your machine doesn't have MTRRs, you'll
726 just add about 9 KB to your kernel.
728 See <file:Documentation/mtrr.txt> for more information.
731 bool "Boot from EFI support"
735 This enables the kernel to boot on EFI platforms using
736 system configuration information passed to it from the firmware.
737 This also enables the kernel to use any EFI runtime services that are
738 available (such as the EFI variable services).
740 This option is only useful on systems that have EFI firmware
741 and will result in a kernel image that is ~8k larger. In addition,
742 you must use the latest ELILO loader available at
743 <http://elilo.sourceforge.net> in order to take advantage of
744 kernel initialization using EFI information (neither GRUB nor LILO know
745 anything about EFI). However, even with this option, the resultant
746 kernel should continue to boot on existing non-EFI platforms.
749 bool "Enable kernel irq balancing"
750 depends on SMP && X86_IO_APIC
753 The default yes will allow the kernel to do irq load balancing.
754 Saying no will keep the kernel from doing irq load balancing.
756 # turning this on wastes a bunch of space.
757 # Summit needs it only when NUMA is on
760 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
764 bool "Enable seccomp to safely compute untrusted bytecode"
768 This kernel feature is useful for number crunching applications
769 that may need to compute untrusted bytecode during their
770 execution. By using pipes or other transports made available to
771 the process as file descriptors supporting the read/write
772 syscalls, it's possible to isolate those applications in
773 their own address space using seccomp. Once seccomp is
774 enabled via /proc/<pid>/seccomp, it cannot be disabled
775 and the task is only allowed to execute a few safe syscalls
776 defined by each seccomp mode.
778 If unsure, say Y. Only embedded should say N here.
780 source kernel/Kconfig.hz
783 bool "kexec system call"
785 kexec is a system call that implements the ability to shutdown your
786 current kernel, and to start another kernel. It is like a reboot
787 but it is independent of the system firmware. And like a reboot
788 you can start any kernel with it, not just Linux.
790 The name comes from the similarity to the exec system call.
792 It is an ongoing process to be certain the hardware in a machine
793 is properly shutdown, so do not be surprised if this code does not
794 initially work for you. It may help to enable device hotplugging
795 support. As of this writing the exact hardware interface is
796 strongly in flux, so no good recommendation can be made.
799 bool "kernel crash dumps (EXPERIMENTAL)"
800 depends on EXPERIMENTAL
803 Generate crash dump after being started by kexec.
804 This should be normally only set in special crash dump kernels
805 which are loaded in the main kernel with kexec-tools into
806 a specially reserved region and then later executed after
807 a crash by kdump/kexec. The crash dump kernel must be compiled
808 to a memory address not used by the main kernel or BIOS using
810 For more details see Documentation/kdump/kdump.txt
812 config PHYSICAL_START
813 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
816 This gives the physical address where the kernel is loaded.
818 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
819 bzImage will decompress itself to above physical address and
820 run from there. Otherwise, bzImage will run from the address where
821 it has been loaded by the boot loader and will ignore above physical
824 In normal kdump cases one does not have to set/change this option
825 as now bzImage can be compiled as a completely relocatable image
826 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
827 address. This option is mainly useful for the folks who don't want
828 to use a bzImage for capturing the crash dump and want to use a
829 vmlinux instead. vmlinux is not relocatable hence a kernel needs
830 to be specifically compiled to run from a specific memory area
831 (normally a reserved region) and this option comes handy.
833 So if you are using bzImage for capturing the crash dump, leave
834 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
835 Otherwise if you plan to use vmlinux for capturing the crash dump
836 change this value to start of the reserved region (Typically 16MB
837 0x1000000). In other words, it can be set based on the "X" value as
838 specified in the "crashkernel=YM@XM" command line boot parameter
839 passed to the panic-ed kernel. Typically this parameter is set as
840 crashkernel=64M@16M. Please take a look at
841 Documentation/kdump/kdump.txt for more details about crash dumps.
843 Usage of bzImage for capturing the crash dump is recommended as
844 one does not have to build two kernels. Same kernel can be used
845 as production kernel and capture kernel. Above option should have
846 gone away after relocatable bzImage support is introduced. But it
847 is present because there are users out there who continue to use
848 vmlinux for dump capture. This option should go away down the
851 Don't change this unless you know what you are doing.
854 bool "Build a relocatable kernel(EXPERIMENTAL)"
855 depends on EXPERIMENTAL
857 This build a kernel image that retains relocation information
858 so it can be loaded someplace besides the default 1MB.
859 The relocations tend to the kernel binary about 10% larger,
860 but are discarded at runtime.
862 One use is for the kexec on panic case where the recovery kernel
863 must live at a different physical address than the primary
866 config PHYSICAL_ALIGN
867 hex "Alignment value to which kernel should be aligned"
869 range 0x2000 0x400000
871 This value puts the alignment restrictions on physical address
872 where kernel is loaded and run from. Kernel is compiled for an
873 address which meets above alignment restriction.
875 If bootloader loads the kernel at a non-aligned address and
876 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
877 address aligned to above value and run from there.
879 If bootloader loads the kernel at a non-aligned address and
880 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
881 load address and decompress itself to the address it has been
882 compiled for and run from there. The address for which kernel is
883 compiled already meets above alignment restrictions. Hence the
884 end result is that kernel runs from a physical address meeting
885 above alignment restrictions.
887 Don't change this unless you know what you are doing.
890 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
891 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
893 Say Y here to experiment with turning CPUs off and on, and to
894 enable suspend on SMP systems. CPUs can be controlled through
895 /sys/devices/system/cpu.
898 bool "Compat VDSO support"
901 Map the VDSO to the predictable old-style address too.
903 Say N here if you are running a sufficiently recent glibc
904 version (2.3.3 or later), to remove the high-mapped
905 VDSO mapping and to exclusively use the randomized VDSO.
911 config ARCH_ENABLE_MEMORY_HOTPLUG
915 menu "Power management options (ACPI, APM)"
916 depends on !X86_VOYAGER
918 source kernel/power/Kconfig
920 source "drivers/acpi/Kconfig"
923 tristate "APM (Advanced Power Management) BIOS support"
924 depends on PM && !X86_VISWS
926 APM is a BIOS specification for saving power using several different
927 techniques. This is mostly useful for battery powered laptops with
928 APM compliant BIOSes. If you say Y here, the system time will be
929 reset after a RESUME operation, the /proc/apm device will provide
930 battery status information, and user-space programs will receive
931 notification of APM "events" (e.g. battery status change).
933 If you select "Y" here, you can disable actual use of the APM
934 BIOS by passing the "apm=off" option to the kernel at boot time.
936 Note that the APM support is almost completely disabled for
937 machines with more than one CPU.
939 In order to use APM, you will need supporting software. For location
940 and more information, read <file:Documentation/pm.txt> and the
941 Battery Powered Linux mini-HOWTO, available from
942 <http://www.tldp.org/docs.html#howto>.
944 This driver does not spin down disk drives (see the hdparm(8)
945 manpage ("man 8 hdparm") for that), and it doesn't turn off
946 VESA-compliant "green" monitors.
948 This driver does not support the TI 4000M TravelMate and the ACER
949 486/DX4/75 because they don't have compliant BIOSes. Many "green"
950 desktop machines also don't have compliant BIOSes, and this driver
951 may cause those machines to panic during the boot phase.
953 Generally, if you don't have a battery in your machine, there isn't
954 much point in using this driver and you should say N. If you get
955 random kernel OOPSes or reboots that don't seem to be related to
956 anything, try disabling/enabling this option (or disabling/enabling
959 Some other things you should try when experiencing seemingly random,
962 1) make sure that you have enough swap space and that it is
964 2) pass the "no-hlt" option to the kernel
965 3) switch on floating point emulation in the kernel and pass
966 the "no387" option to the kernel
967 4) pass the "floppy=nodma" option to the kernel
968 5) pass the "mem=4M" option to the kernel (thereby disabling
969 all but the first 4 MB of RAM)
970 6) make sure that the CPU is not over clocked.
971 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
972 8) disable the cache from your BIOS settings
973 9) install a fan for the video card or exchange video RAM
974 10) install a better fan for the CPU
975 11) exchange RAM chips
976 12) exchange the motherboard.
978 To compile this driver as a module, choose M here: the
979 module will be called apm.
983 config APM_IGNORE_USER_SUSPEND
984 bool "Ignore USER SUSPEND"
986 This option will ignore USER SUSPEND requests. On machines with a
987 compliant APM BIOS, you want to say N. However, on the NEC Versa M
988 series notebooks, it is necessary to say Y because of a BIOS bug.
991 bool "Enable PM at boot time"
993 Enable APM features at boot time. From page 36 of the APM BIOS
994 specification: "When disabled, the APM BIOS does not automatically
995 power manage devices, enter the Standby State, enter the Suspend
996 State, or take power saving steps in response to CPU Idle calls."
997 This driver will make CPU Idle calls when Linux is idle (unless this
998 feature is turned off -- see "Do CPU IDLE calls", below). This
999 should always save battery power, but more complicated APM features
1000 will be dependent on your BIOS implementation. You may need to turn
1001 this option off if your computer hangs at boot time when using APM
1002 support, or if it beeps continuously instead of suspending. Turn
1003 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1004 T400CDT. This is off by default since most machines do fine without
1008 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"
1021 Enable console blanking using the APM. Some laptops can use this to
1022 turn off the LCD backlight when the screen blanker of the Linux
1023 virtual console blanks the screen. Note that this is only used by
1024 the virtual console screen blanker, and won't turn off the backlight
1025 when using the X Window system. This also doesn't have anything to
1026 do with your VESA-compliant power-saving monitor. Further, this
1027 option doesn't work for all laptops -- it might not turn off your
1028 backlight at all, or it might print a lot of errors to the console,
1029 especially if you are using gpm.
1031 config APM_ALLOW_INTS
1032 bool "Allow interrupts during APM BIOS calls"
1034 Normally we disable external interrupts while we are making calls to
1035 the APM BIOS as a measure to lessen the effects of a badly behaving
1036 BIOS implementation. The BIOS should reenable interrupts if it
1037 needs to. Unfortunately, some BIOSes do not -- especially those in
1038 many of the newer IBM Thinkpads. If you experience hangs when you
1039 suspend, try setting this to Y. Otherwise, say N.
1041 config APM_REAL_MODE_POWER_OFF
1042 bool "Use real mode APM BIOS call to power off"
1044 Use real mode APM BIOS calls to switch off the computer. This is
1045 a work-around for a number of buggy BIOSes. Switch this option on if
1046 your computer crashes instead of powering off properly.
1050 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1054 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1057 bool "PCI support" if !X86_VISWS
1058 depends on !X86_VOYAGER
1059 default y if X86_VISWS
1060 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1062 Find out whether you have a PCI motherboard. PCI is the name of a
1063 bus system, i.e. the way the CPU talks to the other stuff inside
1064 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1065 VESA. If you have PCI, say Y, otherwise N.
1067 The PCI-HOWTO, available from
1068 <http://www.tldp.org/docs.html#howto>, contains valuable
1069 information about which PCI hardware does work under Linux and which
1073 prompt "PCI access mode"
1074 depends on PCI && !X86_VISWS
1077 On PCI systems, the BIOS can be used to detect the PCI devices and
1078 determine their configuration. However, some old PCI motherboards
1079 have BIOS bugs and may crash if this is done. Also, some embedded
1080 PCI-based systems don't have any BIOS at all. Linux can also try to
1081 detect the PCI hardware directly without using the BIOS.
1083 With this option, you can specify how Linux should detect the
1084 PCI devices. If you choose "BIOS", the BIOS will be used,
1085 if you choose "Direct", the BIOS won't be used, and if you
1086 choose "MMConfig", then PCI Express MMCONFIG will be used.
1087 If you choose "Any", the kernel will try MMCONFIG, then the
1088 direct access method and falls back to the BIOS if that doesn't
1089 work. If unsure, go with the default, which is "Any".
1094 config PCI_GOMMCONFIG
1107 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1112 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1117 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1120 source "drivers/pci/pcie/Kconfig"
1122 source "drivers/pci/Kconfig"
1130 depends on !(X86_VOYAGER || X86_VISWS)
1132 Find out whether you have ISA slots on your motherboard. ISA is the
1133 name of a bus system, i.e. the way the CPU talks to the other stuff
1134 inside your box. Other bus systems are PCI, EISA, MicroChannel
1135 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1136 newer boards don't support it. If you have ISA, say Y, otherwise N.
1142 The Extended Industry Standard Architecture (EISA) bus was
1143 developed as an open alternative to the IBM MicroChannel bus.
1145 The EISA bus provided some of the features of the IBM MicroChannel
1146 bus while maintaining backward compatibility with cards made for
1147 the older ISA bus. The EISA bus saw limited use between 1988 and
1148 1995 when it was made obsolete by the PCI bus.
1150 Say Y here if you are building a kernel for an EISA-based machine.
1154 source "drivers/eisa/Kconfig"
1157 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1158 default y if X86_VOYAGER
1160 MicroChannel Architecture is found in some IBM PS/2 machines and
1161 laptops. It is a bus system similar to PCI or ISA. See
1162 <file:Documentation/mca.txt> (and especially the web page given
1163 there) before attempting to build an MCA bus kernel.
1165 source "drivers/mca/Kconfig"
1168 tristate "NatSemi SCx200 support"
1169 depends on !X86_VOYAGER
1171 This provides basic support for National Semiconductor's
1172 (now AMD's) Geode processors. The driver probes for the
1173 PCI-IDs of several on-chip devices, so its a good dependency
1174 for other scx200_* drivers.
1176 If compiled as a module, the driver is named scx200.
1178 config SCx200HR_TIMER
1179 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1180 depends on SCx200 && GENERIC_TIME
1183 This driver provides a clocksource built upon the on-chip
1184 27MHz high-resolution timer. Its also a workaround for
1185 NSC Geode SC-1100's buggy TSC, which loses time when the
1186 processor goes idle (as is done by the scheduler). The
1187 other workaround is idle=poll boot option.
1191 depends on AGP_AMD64
1193 source "drivers/pcmcia/Kconfig"
1195 source "drivers/pci/hotplug/Kconfig"
1199 menu "Executable file formats"
1201 source "fs/Kconfig.binfmt"
1205 source "net/Kconfig"
1207 source "drivers/Kconfig"
1211 menu "Instrumentation Support"
1212 depends on EXPERIMENTAL
1214 source "arch/i386/oprofile/Kconfig"
1217 bool "Kprobes (EXPERIMENTAL)"
1218 depends on KALLSYMS && EXPERIMENTAL && MODULES
1220 Kprobes allows you to trap at almost any kernel address and
1221 execute a callback function. register_kprobe() establishes
1222 a probepoint and specifies the callback. Kprobes is useful
1223 for kernel debugging, non-intrusive instrumentation and testing.
1224 If in doubt, say "N".
1227 source "arch/i386/Kconfig.debug"
1229 source "security/Kconfig"
1231 source "crypto/Kconfig"
1233 source "lib/Kconfig"
1236 # Use the generic interrupt handling code in kernel/irq/:
1238 config GENERIC_HARDIRQS
1242 config GENERIC_IRQ_PROBE
1246 config GENERIC_PENDING_IRQ
1248 depends on GENERIC_HARDIRQS && SMP
1253 depends on SMP && !X86_VOYAGER
1258 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1261 config X86_BIOS_REBOOT
1263 depends on !(X86_VISWS || X86_VOYAGER)
1266 config X86_TRAMPOLINE
1268 depends on X86_SMP || (X86_VOYAGER && SMP)
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