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.
22 config LOCKDEP_SUPPORT
26 config STACKTRACE_SUPPORT
30 config SEMAPHORE_SLEEPERS
45 config GENERIC_ISA_DMA
58 config GENERIC_HWEIGHT
62 config ARCH_MAY_HAVE_PC_FDC
72 menu "Processor type and features"
75 bool "Symmetric multi-processing support"
77 This enables support for systems with more than one CPU. If you have
78 a system with only one CPU, like most personal computers, say N. If
79 you have a system with more than one CPU, say Y.
81 If you say N here, the kernel will run on single and multiprocessor
82 machines, but will use only one CPU of a multiprocessor machine. If
83 you say Y here, the kernel will run on many, but not all,
84 singleprocessor machines. On a singleprocessor machine, the kernel
85 will run faster if you say N here.
87 Note that if you say Y here and choose architecture "586" or
88 "Pentium" under "Processor family", the kernel will not work on 486
89 architectures. Similarly, multiprocessor kernels for the "PPro"
90 architecture may not work on all Pentium based boards.
92 People using multiprocessor machines who say Y here should also say
93 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
94 Management" code will be disabled if you say Y here.
96 See also the <file:Documentation/smp.txt>,
97 <file:Documentation/i386/IO-APIC.txt>,
98 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
99 <http://www.tldp.org/docs.html#howto>.
101 If you don't know what to do here, say N.
104 prompt "Subarchitecture Type"
110 Choose this option if your computer is a standard PC or compatible.
113 bool "Xen-compatible"
114 select X86_UP_APIC if !SMP && XEN_PRIVILEGED_GUEST
115 select X86_UP_IOAPIC if !SMP && XEN_PRIVILEGED_GUEST
118 Choose this option if you plan to run this kernel on top of the
124 Select this for an AMD Elan processor.
126 Do not use this option for K6/Athlon/Opteron processors!
128 If unsure, choose "PC-compatible" instead.
133 Voyager is an MCA-based 32-way capable SMP architecture proprietary
134 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
138 If you do not specifically know you have a Voyager based machine,
139 say N here, otherwise the kernel you build will not be bootable.
142 bool "NUMAQ (IBM/Sequent)"
146 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
147 multiquad box. This changes the way that processors are bootstrapped,
148 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
149 You will need a new lynxer.elf file to flash your firmware with - send
150 email to <Martin.Bligh@us.ibm.com>.
153 bool "Summit/EXA (IBM x440)"
156 This option is needed for IBM systems that use the Summit/EXA chipset.
157 In particular, it is needed for the x440.
159 If you don't have one of these computers, you should say N here.
160 If you want to build a NUMA kernel, you must select ACPI.
163 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
166 This option is needed for the systems that have more than 8 CPUs
167 and if the system is not of any sub-arch type above.
169 If you don't have such a system, you should say N here.
172 bool "SGI 320/540 (Visual Workstation)"
174 The SGI Visual Workstation series is an IA32-based workstation
175 based on SGI systems chips with some legacy PC hardware attached.
177 Say Y here to create a kernel to run on the SGI 320 or 540.
179 A kernel compiled for the Visual Workstation will not run on PCs
180 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
182 config X86_GENERICARCH
183 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
185 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
186 It is intended for a generic binary kernel.
187 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
190 bool "Support for Unisys ES7000 IA32 series"
193 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
194 supposed to run on an IA32-based Unisys ES7000 system.
195 Only choose this option if you have such a system, otherwise you
201 bool "Paravirtualization support (EXPERIMENTAL)"
202 depends on EXPERIMENTAL
203 depends on !(X86_VISWS || X86_VOYAGER)
205 Paravirtualization is a way of running multiple instances of
206 Linux on the same machine, under a hypervisor. This option
207 changes the kernel so it can modify itself when it is run
208 under a hypervisor, improving performance significantly.
209 However, when run without a hypervisor the kernel is
210 theoretically slower. If in doubt, say N.
215 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
218 config HAVE_ARCH_PARSE_SRAT
223 config X86_SUMMIT_NUMA
226 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
228 config X86_CYCLONE_TIMER
231 depends on X86_SUMMIT || X86_GENERICARCH
233 config ES7000_CLUSTERED_APIC
236 depends on SMP && X86_ES7000 && MPENTIUMIII
238 source "arch/i386/Kconfig.cpu"
241 bool "HPET Timer Support"
244 This enables the use of the HPET for the kernel's internal timer.
245 HPET is the next generation timer replacing legacy 8254s.
246 You can safely choose Y here. However, HPET will only be
247 activated if the platform and the BIOS support this feature.
248 Otherwise the 8254 will be used for timing services.
250 Choose N to continue using the legacy 8254 timer.
252 config HPET_EMULATE_RTC
254 depends on HPET_TIMER && RTC=y
258 int "Maximum number of CPUs (2-255)"
261 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
264 This allows you to specify the maximum number of CPUs which this
265 kernel will support. The maximum supported value is 255 and the
266 minimum value which makes sense is 2.
268 This is purely to save memory - each supported CPU adds
269 approximately eight kilobytes to the kernel image.
272 bool "SMT (Hyperthreading) scheduler support"
275 SMT scheduler support improves the CPU scheduler's decision making
276 when dealing with Intel Pentium 4 chips with HyperThreading at a
277 cost of slightly increased overhead in some places. If unsure say
281 bool "Multi-core scheduler support"
285 Multi-core scheduler support improves the CPU scheduler's decision
286 making when dealing with multi-core CPU chips at a cost of slightly
287 increased overhead in some places. If unsure say N here.
289 source "kernel/Kconfig.preempt"
292 bool "Local APIC support on uniprocessors"
293 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH || XEN_UNPRIVILEGED_GUEST)
295 A local APIC (Advanced Programmable Interrupt Controller) is an
296 integrated interrupt controller in the CPU. If you have a single-CPU
297 system which has a processor with a local APIC, you can say Y here to
298 enable and use it. If you say Y here even though your machine doesn't
299 have a local APIC, then the kernel will still run with no slowdown at
300 all. The local APIC supports CPU-generated self-interrupts (timer,
301 performance counters), and the NMI watchdog which detects hard
305 bool "IO-APIC support on uniprocessors"
306 depends on X86_UP_APIC
308 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
309 SMP-capable replacement for PC-style interrupt controllers. Most
310 SMP systems and many recent uniprocessor systems have one.
312 If you have a single-CPU system with an IO-APIC, you can say Y here
313 to use it. If you say Y here even though your machine doesn't have
314 an IO-APIC, then the kernel will still run with no slowdown at all.
316 config X86_LOCAL_APIC
318 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !(X86_VOYAGER || XEN_UNPRIVILEGED_GUEST)) || X86_GENERICARCH
323 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER || XEN_UNPRIVILEGED_GUEST)) || X86_GENERICARCH
326 config X86_VISWS_APIC
332 bool "Machine Check Exception"
333 depends on !(X86_VOYAGER || X86_XEN)
335 Machine Check Exception support allows the processor to notify the
336 kernel if it detects a problem (e.g. overheating, component failure).
337 The action the kernel takes depends on the severity of the problem,
338 ranging from a warning message on the console, to halting the machine.
339 Your processor must be a Pentium or newer to support this - check the
340 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
341 have a design flaw which leads to false MCE events - hence MCE is
342 disabled on all P5 processors, unless explicitly enabled with "mce"
343 as a boot argument. Similarly, if MCE is built in and creates a
344 problem on some new non-standard machine, you can boot with "nomce"
345 to disable it. MCE support simply ignores non-MCE processors like
346 the 386 and 486, so nearly everyone can say Y here.
348 config X86_MCE_NONFATAL
349 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
352 Enabling this feature starts a timer that triggers every 5 seconds which
353 will look at the machine check registers to see if anything happened.
354 Non-fatal problems automatically get corrected (but still logged).
355 Disable this if you don't want to see these messages.
356 Seeing the messages this option prints out may be indicative of dying hardware,
357 or out-of-spec (ie, overclocked) hardware.
358 This option only does something on certain CPUs.
359 (AMD Athlon/Duron and Intel Pentium 4)
361 config X86_MCE_P4THERMAL
362 bool "check for P4 thermal throttling interrupt."
363 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
365 Enabling this feature will cause a message to be printed when the P4
366 enters thermal throttling.
370 bool "Enable VM86 support" if EMBEDDED
372 This option is required by programs like DOSEMU to run 16-bit legacy
373 code on X86 processors. It also may be needed by software like
374 XFree86 to initialize some video cards via BIOS. Disabling this
375 option saves about 6k.
378 tristate "Toshiba Laptop support"
380 This adds a driver to safely access the System Management Mode of
381 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
382 not work on models with a Phoenix BIOS. The System Management Mode
383 is used to set the BIOS and power saving options on Toshiba portables.
385 For information on utilities to make use of this driver see the
386 Toshiba Linux utilities web site at:
387 <http://www.buzzard.org.uk/toshiba/>.
389 Say Y if you intend to run this kernel on a Toshiba portable.
393 tristate "Dell laptop support"
395 This adds a driver to safely access the System Management Mode
396 of the CPU on the Dell Inspiron 8000. The System Management Mode
397 is used to read cpu temperature and cooling fan status and to
398 control the fans on the I8K portables.
400 This driver has been tested only on the Inspiron 8000 but it may
401 also work with other Dell laptops. You can force loading on other
402 models by passing the parameter `force=1' to the module. Use at
405 For information on utilities to make use of this driver see the
406 I8K Linux utilities web site at:
407 <http://people.debian.org/~dz/i8k/>
409 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
412 config X86_REBOOTFIXUPS
413 bool "Enable X86 board specific fixups for reboot"
417 This enables chipset and/or board specific fixups to be done
418 in order to get reboot to work correctly. This is only needed on
419 some combinations of hardware and BIOS. The symptom, for which
420 this config is intended, is when reboot ends with a stalled/hung
423 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
426 Say Y if you want to enable the fixup. Currently, it's safe to
427 enable this option even if you don't need it.
431 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
432 depends on !XEN_UNPRIVILEGED_GUEST
435 If you say Y here and also to "/dev file system support" in the
436 'File systems' section, you will be able to update the microcode on
437 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
438 Pentium III, Pentium 4, Xeon etc. You will obviously need the
439 actual microcode binary data itself which is not shipped with the
442 For latest news and information on obtaining all the required
443 ingredients for this driver, check:
444 <http://www.urbanmyth.org/microcode/>.
446 To compile this driver as a module, choose M here: the
447 module will be called microcode.
449 config MICROCODE_OLD_INTERFACE
455 tristate "/dev/cpu/*/msr - Model-specific register support"
458 This device gives privileged processes access to the x86
459 Model-Specific Registers (MSRs). It is a character device with
460 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
461 MSR accesses are directed to a specific CPU on multi-processor
465 tristate "/dev/cpu/*/cpuid - CPU information support"
467 This device gives processes access to the x86 CPUID instruction to
468 be executed on a specific processor. It is a character device
469 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
476 source "drivers/firmware/Kconfig"
479 prompt "High Memory Support"
480 default HIGHMEM4G if !X86_NUMAQ
481 default HIGHMEM64G if X86_NUMAQ
485 depends on !X86_NUMAQ
487 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
488 However, the address space of 32-bit x86 processors is only 4
489 Gigabytes large. That means that, if you have a large amount of
490 physical memory, not all of it can be "permanently mapped" by the
491 kernel. The physical memory that's not permanently mapped is called
494 If you are compiling a kernel which will never run on a machine with
495 more than 1 Gigabyte total physical RAM, answer "off" here (default
496 choice and suitable for most users). This will result in a "3GB/1GB"
497 split: 3GB are mapped so that each process sees a 3GB virtual memory
498 space and the remaining part of the 4GB virtual memory space is used
499 by the kernel to permanently map as much physical memory as
502 If the machine has between 1 and 4 Gigabytes physical RAM, then
505 If more than 4 Gigabytes is used then answer "64GB" here. This
506 selection turns Intel PAE (Physical Address Extension) mode on.
507 PAE implements 3-level paging on IA32 processors. PAE is fully
508 supported by Linux, PAE mode is implemented on all recent Intel
509 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
510 then the kernel will not boot on CPUs that don't support PAE!
512 The actual amount of total physical memory will either be
513 auto detected or can be forced by using a kernel command line option
514 such as "mem=256M". (Try "man bootparam" or see the documentation of
515 your boot loader (lilo or loadlin) about how to pass options to the
516 kernel at boot time.)
518 If unsure, say "off".
522 depends on !X86_NUMAQ
524 Select this if you have a 32-bit processor and between 1 and 4
525 gigabytes of physical RAM.
529 depends on X86_CMPXCHG64
531 Select this if you have a 32-bit processor and more than 4
532 gigabytes of physical RAM.
537 depends on EXPERIMENTAL
538 prompt "Memory split" if EMBEDDED
541 Select the desired split between kernel and user memory.
543 If the address range available to the kernel is less than the
544 physical memory installed, the remaining memory will be available
545 as "high memory". Accessing high memory is a little more costly
546 than low memory, as it needs to be mapped into the kernel first.
547 Note that increasing the kernel address space limits the range
548 available to user programs, making the address space there
549 tighter. Selecting anything other than the default 3G/1G split
550 will also likely make your kernel incompatible with binary-only
553 If you are not absolutely sure what you are doing, leave this
557 bool "3G/1G user/kernel split"
558 config VMSPLIT_3G_OPT
560 bool "3G/1G user/kernel split (for full 1G low memory)"
562 bool "2G/2G user/kernel split"
564 bool "1G/3G user/kernel split"
569 default 0xB0000000 if VMSPLIT_3G_OPT
570 default 0x78000000 if VMSPLIT_2G
571 default 0x40000000 if VMSPLIT_1G
576 depends on HIGHMEM64G || HIGHMEM4G
581 depends on HIGHMEM64G
583 select RESOURCES_64BIT
585 # Common NUMA Features
587 bool "Numa Memory Allocation and Scheduler Support"
588 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
590 default y if (X86_NUMAQ || X86_SUMMIT)
592 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
593 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
597 default "4" if X86_NUMAQ
599 depends on NEED_MULTIPLE_NODES
601 config HAVE_ARCH_BOOTMEM_NODE
606 config ARCH_HAVE_MEMORY_PRESENT
608 depends on DISCONTIGMEM
611 config NEED_NODE_MEMMAP_SIZE
613 depends on DISCONTIGMEM || SPARSEMEM
616 config HAVE_ARCH_ALLOC_REMAP
621 config ARCH_FLATMEM_ENABLE
623 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
625 config ARCH_DISCONTIGMEM_ENABLE
629 config ARCH_DISCONTIGMEM_DEFAULT
633 config ARCH_SPARSEMEM_ENABLE
635 depends on (NUMA || (X86_PC && EXPERIMENTAL))
636 select SPARSEMEM_STATIC
638 config ARCH_SELECT_MEMORY_MODEL
640 depends on ARCH_SPARSEMEM_ENABLE
642 config ARCH_POPULATES_NODE_MAP
648 bool "Allocate 3rd-level pagetables from highmem"
649 depends on (HIGHMEM4G || HIGHMEM64G) && !X86_XEN
651 The VM uses one page table entry for each page of physical memory.
652 For systems with a lot of RAM, this can be wasteful of precious
653 low memory. Setting this option will put user-space page table
654 entries in high memory.
656 config MATH_EMULATION
657 bool "Math emulation"
660 Linux can emulate a math coprocessor (used for floating point
661 operations) if you don't have one. 486DX and Pentium processors have
662 a math coprocessor built in, 486SX and 386 do not, unless you added
663 a 487DX or 387, respectively. (The messages during boot time can
664 give you some hints here ["man dmesg"].) Everyone needs either a
665 coprocessor or this emulation.
667 If you don't have a math coprocessor, you need to say Y here; if you
668 say Y here even though you have a coprocessor, the coprocessor will
669 be used nevertheless. (This behavior can be changed with the kernel
670 command line option "no387", which comes handy if your coprocessor
671 is broken. Try "man bootparam" or see the documentation of your boot
672 loader (lilo or loadlin) about how to pass options to the kernel at
673 boot time.) This means that it is a good idea to say Y here if you
674 intend to use this kernel on different machines.
676 More information about the internals of the Linux math coprocessor
677 emulation can be found in <file:arch/i386/math-emu/README>.
679 If you are not sure, say Y; apart from resulting in a 66 KB bigger
680 kernel, it won't hurt.
683 bool "MTRR (Memory Type Range Register) support"
684 depends on !XEN_UNPRIVILEGED_GUEST
687 On Intel P6 family processors (Pentium Pro, Pentium II and later)
688 the Memory Type Range Registers (MTRRs) may be used to control
689 processor access to memory ranges. This is most useful if you have
690 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
691 allows bus write transfers to be combined into a larger transfer
692 before bursting over the PCI/AGP bus. This can increase performance
693 of image write operations 2.5 times or more. Saying Y here creates a
694 /proc/mtrr file which may be used to manipulate your processor's
695 MTRRs. Typically the X server should use this.
697 This code has a reasonably generic interface so that similar
698 control registers on other processors can be easily supported
701 The Cyrix 6x86, 6x86MX and M II processors have Address Range
702 Registers (ARRs) which provide a similar functionality to MTRRs. For
703 these, the ARRs are used to emulate the MTRRs.
704 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
705 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
706 write-combining. All of these processors are supported by this code
707 and it makes sense to say Y here if you have one of them.
709 Saying Y here also fixes a problem with buggy SMP BIOSes which only
710 set the MTRRs for the boot CPU and not for the secondary CPUs. This
711 can lead to all sorts of problems, so it's good to say Y here.
713 You can safely say Y even if your machine doesn't have MTRRs, you'll
714 just add about 9 KB to your kernel.
716 See <file:Documentation/mtrr.txt> for more information.
719 bool "Boot from EFI support"
720 depends on ACPI && !X86_XEN
723 This enables the kernel to boot on EFI platforms using
724 system configuration information passed to it from the firmware.
725 This also enables the kernel to use any EFI runtime services that are
726 available (such as the EFI variable services).
728 This option is only useful on systems that have EFI firmware
729 and will result in a kernel image that is ~8k larger. In addition,
730 you must use the latest ELILO loader available at
731 <http://elilo.sourceforge.net> in order to take advantage of
732 kernel initialization using EFI information (neither GRUB nor LILO know
733 anything about EFI). However, even with this option, the resultant
734 kernel should continue to boot on existing non-EFI platforms.
737 bool "Enable kernel irq balancing"
738 depends on SMP && X86_IO_APIC && !X86_XEN
741 The default yes will allow the kernel to do irq load balancing.
742 Saying no will keep the kernel from doing irq load balancing.
744 # turning this on wastes a bunch of space.
745 # Summit needs it only when NUMA is on
748 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
752 bool "Enable seccomp to safely compute untrusted bytecode"
756 This kernel feature is useful for number crunching applications
757 that may need to compute untrusted bytecode during their
758 execution. By using pipes or other transports made available to
759 the process as file descriptors supporting the read/write
760 syscalls, it's possible to isolate those applications in
761 their own address space using seccomp. Once seccomp is
762 enabled via /proc/<pid>/seccomp, it cannot be disabled
763 and the task is only allowed to execute a few safe syscalls
764 defined by each seccomp mode.
766 If unsure, say Y. Only embedded should say N here.
768 source kernel/Kconfig.hz
771 bool "kexec system call"
774 kexec is a system call that implements the ability to shutdown your
775 current kernel, and to start another kernel. It is like a reboot
776 but it is independent of the system firmware. And like a reboot
777 you can start any kernel with it, not just Linux.
779 The name comes from the similarity to the exec system call.
781 It is an ongoing process to be certain the hardware in a machine
782 is properly shutdown, so do not be surprised if this code does not
783 initially work for you. It may help to enable device hotplugging
784 support. As of this writing the exact hardware interface is
785 strongly in flux, so no good recommendation can be made.
788 bool "kernel crash dumps (EXPERIMENTAL)"
789 depends on EXPERIMENTAL
792 Generate crash dump after being started by kexec.
793 This should be normally only set in special crash dump kernels
794 which are loaded in the main kernel with kexec-tools into
795 a specially reserved region and then later executed after
796 a crash by kdump/kexec. The crash dump kernel must be compiled
797 to a memory address not used by the main kernel or BIOS using
799 For more details see Documentation/kdump/kdump.txt
801 config PHYSICAL_START
802 hex "Physical address where the kernel is loaded"
805 This gives the physical address where the kernel is loaded.
807 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
808 bzImage will decompress itself to above physical address and
809 run from there. Otherwise, bzImage will run from the address where
810 it has been loaded by the boot loader and will ignore above physical
813 In normal kdump cases one does not have to set/change this option
814 as now bzImage can be compiled as a completely relocatable image
815 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
816 address. This option is mainly useful for the folks who don't want
817 to use a bzImage for capturing the crash dump and want to use a
818 vmlinux instead. vmlinux is not relocatable hence a kernel needs
819 to be specifically compiled to run from a specific memory area
820 (normally a reserved region) and this option comes handy.
822 So if you are using bzImage for capturing the crash dump, leave
823 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
824 Otherwise if you plan to use vmlinux for capturing the crash dump
825 change this value to start of the reserved region (Typically 16MB
826 0x1000000). In other words, it can be set based on the "X" value as
827 specified in the "crashkernel=YM@XM" command line boot parameter
828 passed to the panic-ed kernel. Typically this parameter is set as
829 crashkernel=64M@16M. Please take a look at
830 Documentation/kdump/kdump.txt for more details about crash dumps.
832 Usage of bzImage for capturing the crash dump is recommended as
833 one does not have to build two kernels. Same kernel can be used
834 as production kernel and capture kernel. Above option should have
835 gone away after relocatable bzImage support is introduced. But it
836 is present because there are users out there who continue to use
837 vmlinux for dump capture. This option should go away down the
840 Don't change this unless you know what you are doing.
843 bool "Build a relocatable kernel(EXPERIMENTAL)"
844 depends on EXPERIMENTAL
846 This build a kernel image that retains relocation information
847 so it can be loaded someplace besides the default 1MB.
848 The relocations tend to the kernel binary about 10% larger,
849 but are discarded at runtime.
851 One use is for the kexec on panic case where the recovery kernel
852 must live at a different physical address than the primary
855 config PHYSICAL_ALIGN
856 hex "Alignment value to which kernel should be aligned"
858 range 0x2000 0x400000
860 This value puts the alignment restrictions on physical address
861 where kernel is loaded and run from. Kernel is compiled for an
862 address which meets above alignment restriction.
864 If bootloader loads the kernel at a non-aligned address and
865 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
866 address aligned to above value and run from there.
868 If bootloader loads the kernel at a non-aligned address and
869 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
870 load address and decompress itself to the address it has been
871 compiled for and run from there. The address for which kernel is
872 compiled already meets above alignment restrictions. Hence the
873 end result is that kernel runs from a physical address meeting
874 above alignment restrictions.
876 Don't change this unless you know what you are doing.
879 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
880 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
882 Say Y here to experiment with turning CPUs off and on, and to
883 enable suspend on SMP systems. CPUs can be controlled through
884 /sys/devices/system/cpu.
887 bool "Compat VDSO support"
891 Map the VDSO to the predictable old-style address too.
893 Say N here if you are running a sufficiently recent glibc
894 version (2.3.3 or later), to remove the high-mapped
895 VDSO mapping and to exclusively use the randomized VDSO.
901 config ARCH_ENABLE_MEMORY_HOTPLUG
905 menu "Power management options (ACPI, APM)"
906 depends on !(X86_VOYAGER || XEN_UNPRIVILEGED_GUEST)
909 source kernel/power/Kconfig
912 source "drivers/acpi/Kconfig"
914 menu "APM (Advanced Power Management) BIOS Support"
915 depends on PM && !(X86_VISWS || X86_XEN)
918 tristate "APM (Advanced Power Management) BIOS support"
919 depends on PM && PM_LEGACY
921 APM is a BIOS specification for saving power using several different
922 techniques. This is mostly useful for battery powered laptops with
923 APM compliant BIOSes. If you say Y here, the system time will be
924 reset after a RESUME operation, the /proc/apm device will provide
925 battery status information, and user-space programs will receive
926 notification of APM "events" (e.g. battery status change).
928 If you select "Y" here, you can disable actual use of the APM
929 BIOS by passing the "apm=off" option to the kernel at boot time.
931 Note that the APM support is almost completely disabled for
932 machines with more than one CPU.
934 In order to use APM, you will need supporting software. For location
935 and more information, read <file:Documentation/pm.txt> and the
936 Battery Powered Linux mini-HOWTO, available from
937 <http://www.tldp.org/docs.html#howto>.
939 This driver does not spin down disk drives (see the hdparm(8)
940 manpage ("man 8 hdparm") for that), and it doesn't turn off
941 VESA-compliant "green" monitors.
943 This driver does not support the TI 4000M TravelMate and the ACER
944 486/DX4/75 because they don't have compliant BIOSes. Many "green"
945 desktop machines also don't have compliant BIOSes, and this driver
946 may cause those machines to panic during the boot phase.
948 Generally, if you don't have a battery in your machine, there isn't
949 much point in using this driver and you should say N. If you get
950 random kernel OOPSes or reboots that don't seem to be related to
951 anything, try disabling/enabling this option (or disabling/enabling
954 Some other things you should try when experiencing seemingly random,
957 1) make sure that you have enough swap space and that it is
959 2) pass the "no-hlt" option to the kernel
960 3) switch on floating point emulation in the kernel and pass
961 the "no387" option to the kernel
962 4) pass the "floppy=nodma" option to the kernel
963 5) pass the "mem=4M" option to the kernel (thereby disabling
964 all but the first 4 MB of RAM)
965 6) make sure that the CPU is not over clocked.
966 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
967 8) disable the cache from your BIOS settings
968 9) install a fan for the video card or exchange video RAM
969 10) install a better fan for the CPU
970 11) exchange RAM chips
971 12) exchange the motherboard.
973 To compile this driver as a module, choose M here: the
974 module will be called apm.
976 config APM_IGNORE_USER_SUSPEND
977 bool "Ignore USER SUSPEND"
980 This option will ignore USER SUSPEND requests. On machines with a
981 compliant APM BIOS, you want to say N. However, on the NEC Versa M
982 series notebooks, it is necessary to say Y because of a BIOS bug.
985 bool "Enable PM at boot time"
988 Enable APM features at boot time. From page 36 of the APM BIOS
989 specification: "When disabled, the APM BIOS does not automatically
990 power manage devices, enter the Standby State, enter the Suspend
991 State, or take power saving steps in response to CPU Idle calls."
992 This driver will make CPU Idle calls when Linux is idle (unless this
993 feature is turned off -- see "Do CPU IDLE calls", below). This
994 should always save battery power, but more complicated APM features
995 will be dependent on your BIOS implementation. You may need to turn
996 this option off if your computer hangs at boot time when using APM
997 support, or if it beeps continuously instead of suspending. Turn
998 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
999 T400CDT. This is off by default since most machines do fine without
1003 bool "Make CPU Idle calls when idle"
1006 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1007 On some machines, this can activate improved power savings, such as
1008 a slowed CPU clock rate, when the machine is idle. These idle calls
1009 are made after the idle loop has run for some length of time (e.g.,
1010 333 mS). On some machines, this will cause a hang at boot time or
1011 whenever the CPU becomes idle. (On machines with more than one CPU,
1012 this option does nothing.)
1014 config APM_DISPLAY_BLANK
1015 bool "Enable console blanking using APM"
1018 Enable console blanking using the APM. Some laptops can use this to
1019 turn off the LCD backlight when the screen blanker of the Linux
1020 virtual console blanks the screen. Note that this is only used by
1021 the virtual console screen blanker, and won't turn off the backlight
1022 when using the X Window system. This also doesn't have anything to
1023 do with your VESA-compliant power-saving monitor. Further, this
1024 option doesn't work for all laptops -- it might not turn off your
1025 backlight at all, or it might print a lot of errors to the console,
1026 especially if you are using gpm.
1028 config APM_RTC_IS_GMT
1029 bool "RTC stores time in GMT"
1032 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1033 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1036 It is in fact recommended to store GMT in your RTC, because then you
1037 don't have to worry about daylight savings time changes. The only
1038 reason not to use GMT in your RTC is if you also run a broken OS
1039 that doesn't understand GMT.
1041 config APM_ALLOW_INTS
1042 bool "Allow interrupts during APM BIOS calls"
1045 Normally we disable external interrupts while we are making calls to
1046 the APM BIOS as a measure to lessen the effects of a badly behaving
1047 BIOS implementation. The BIOS should reenable interrupts if it
1048 needs to. Unfortunately, some BIOSes do not -- especially those in
1049 many of the newer IBM Thinkpads. If you experience hangs when you
1050 suspend, try setting this to Y. Otherwise, say N.
1052 config APM_REAL_MODE_POWER_OFF
1053 bool "Use real mode APM BIOS call to power off"
1056 Use real mode APM BIOS calls to switch off the computer. This is
1057 a work-around for a number of buggy BIOSes. Switch this option on if
1058 your computer crashes instead of powering off properly.
1062 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1066 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1069 bool "PCI support" if !X86_VISWS
1070 depends on !X86_VOYAGER
1071 default y if X86_VISWS
1073 Find out whether you have a PCI motherboard. PCI is the name of a
1074 bus system, i.e. the way the CPU talks to the other stuff inside
1075 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1076 VESA. If you have PCI, say Y, otherwise N.
1078 The PCI-HOWTO, available from
1079 <http://www.tldp.org/docs.html#howto>, contains valuable
1080 information about which PCI hardware does work under Linux and which
1084 prompt "PCI access mode"
1085 depends on PCI && !X86_VISWS
1088 On PCI systems, the BIOS can be used to detect the PCI devices and
1089 determine their configuration. However, some old PCI motherboards
1090 have BIOS bugs and may crash if this is done. Also, some embedded
1091 PCI-based systems don't have any BIOS at all. Linux can also try to
1092 detect the PCI hardware directly without using the BIOS.
1094 With this option, you can specify how Linux should detect the
1095 PCI devices. If you choose "BIOS", the BIOS will be used,
1096 if you choose "Direct", the BIOS won't be used, and if you
1097 choose "MMConfig", then PCI Express MMCONFIG will be used.
1098 If you choose "Any", the kernel will try MMCONFIG, then the
1099 direct access method and falls back to the BIOS if that doesn't
1100 work. If unsure, go with the default, which is "Any".
1106 config PCI_GOMMCONFIG
1113 bool "Xen PCI Frontend"
1116 The PCI device frontend driver allows the kernel to import arbitrary
1117 PCI devices from a PCI backend to support PCI driver domains.
1126 depends on !(X86_VISWS || X86_XEN) && PCI && (PCI_GOBIOS || PCI_GOANY)
1131 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1136 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1139 config XEN_PCIDEV_FRONTEND
1141 depends on PCI && X86_XEN && (PCI_GOXEN_FE || PCI_GOANY)
1144 config XEN_PCIDEV_FE_DEBUG
1145 bool "Xen PCI Frontend Debugging"
1146 depends on XEN_PCIDEV_FRONTEND
1149 Enables some debug statements within the PCI Frontend.
1151 source "drivers/pci/pcie/Kconfig"
1153 source "drivers/pci/Kconfig"
1161 depends on !(X86_VOYAGER || X86_VISWS || X86_XEN)
1163 Find out whether you have ISA slots on your motherboard. ISA is the
1164 name of a bus system, i.e. the way the CPU talks to the other stuff
1165 inside your box. Other bus systems are PCI, EISA, MicroChannel
1166 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1167 newer boards don't support it. If you have ISA, say Y, otherwise N.
1173 The Extended Industry Standard Architecture (EISA) bus was
1174 developed as an open alternative to the IBM MicroChannel bus.
1176 The EISA bus provided some of the features of the IBM MicroChannel
1177 bus while maintaining backward compatibility with cards made for
1178 the older ISA bus. The EISA bus saw limited use between 1988 and
1179 1995 when it was made obsolete by the PCI bus.
1181 Say Y here if you are building a kernel for an EISA-based machine.
1185 source "drivers/eisa/Kconfig"
1188 bool "MCA support" if !(X86_VISWS || X86_VOYAGER || X86_XEN)
1189 default y if X86_VOYAGER
1191 MicroChannel Architecture is found in some IBM PS/2 machines and
1192 laptops. It is a bus system similar to PCI or ISA. See
1193 <file:Documentation/mca.txt> (and especially the web page given
1194 there) before attempting to build an MCA bus kernel.
1196 source "drivers/mca/Kconfig"
1199 tristate "NatSemi SCx200 support"
1200 depends on !X86_VOYAGER
1202 This provides basic support for National Semiconductor's
1203 (now AMD's) Geode processors. The driver probes for the
1204 PCI-IDs of several on-chip devices, so its a good dependency
1205 for other scx200_* drivers.
1207 If compiled as a module, the driver is named scx200.
1209 config SCx200HR_TIMER
1210 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1211 depends on SCx200 && GENERIC_TIME
1214 This driver provides a clocksource built upon the on-chip
1215 27MHz high-resolution timer. Its also a workaround for
1216 NSC Geode SC-1100's buggy TSC, which loses time when the
1217 processor goes idle (as is done by the scheduler). The
1218 other workaround is idle=poll boot option.
1222 depends on AGP_AMD64
1224 source "drivers/pcmcia/Kconfig"
1226 source "drivers/pci/hotplug/Kconfig"
1230 menu "Executable file formats"
1232 source "fs/Kconfig.binfmt"
1236 source "net/Kconfig"
1238 source "drivers/Kconfig"
1242 menu "Instrumentation Support"
1243 depends on EXPERIMENTAL
1245 source "arch/i386/oprofile/Kconfig"
1248 bool "Kprobes (EXPERIMENTAL)"
1249 depends on KALLSYMS && EXPERIMENTAL && MODULES
1251 Kprobes allows you to trap at almost any kernel address and
1252 execute a callback function. register_kprobe() establishes
1253 a probepoint and specifies the callback. Kprobes is useful
1254 for kernel debugging, non-intrusive instrumentation and testing.
1255 If in doubt, say "N".
1258 source "arch/i386/Kconfig.debug"
1260 source "kernel/vserver/Kconfig"
1262 source "security/Kconfig"
1264 source "crypto/Kconfig"
1266 source "drivers/xen/Kconfig"
1268 source "lib/Kconfig"
1271 # Use the generic interrupt handling code in kernel/irq/:
1273 config GENERIC_HARDIRQS
1277 config GENERIC_IRQ_PROBE
1281 config GENERIC_PENDING_IRQ
1283 depends on GENERIC_HARDIRQS && SMP
1288 depends on SMP && !X86_VOYAGER
1293 depends on SMP && !(X86_VISWS || X86_VOYAGER || X86_XEN)
1296 config X86_BIOS_REBOOT
1298 depends on !(X86_VISWS || X86_VOYAGER)
1301 config X86_TRAMPOLINE
1303 depends on X86_SMP || (X86_VOYAGER && SMP)
git://git.onelab.eu / linux-2.6.git / blob