2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
6 mainmenu "Linux Kernel Configuration"
12 This is Linux's home port. Linux was originally native to the Intel
13 386, and runs on all the later x86 processors including the Intel
14 486, 586, Pentiums, and various instruction-set-compatible chips by
15 AMD, Cyrix, and others.
21 config CLOCKSOURCE_WATCHDOG
25 config GENERIC_CLOCKEVENTS
29 config GENERIC_CLOCKEVENTS_BROADCAST
33 config LOCKDEP_SUPPORT
37 config STACKTRACE_SUPPORT
41 config SEMAPHORE_SLEEPERS
60 config GENERIC_ISA_DMA
73 config GENERIC_HWEIGHT
77 config ARCH_MAY_HAVE_PC_FDC
87 menu "Processor type and features"
90 bool "Symmetric multi-processing support"
92 This enables support for systems with more than one CPU. If you have
93 a system with only one CPU, like most personal computers, say N. If
94 you have a system with more than one CPU, say Y.
96 If you say N here, the kernel will run on single and multiprocessor
97 machines, but will use only one CPU of a multiprocessor machine. If
98 you say Y here, the kernel will run on many, but not all,
99 singleprocessor machines. On a singleprocessor machine, the kernel
100 will run faster if you say N here.
102 Note that if you say Y here and choose architecture "586" or
103 "Pentium" under "Processor family", the kernel will not work on 486
104 architectures. Similarly, multiprocessor kernels for the "PPro"
105 architecture may not work on all Pentium based boards.
107 People using multiprocessor machines who say Y here should also say
108 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
109 Management" code will be disabled if you say Y here.
111 See also the <file:Documentation/smp.txt>,
112 <file:Documentation/i386/IO-APIC.txt>,
113 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
114 <http://www.tldp.org/docs.html#howto>.
116 If you don't know what to do here, say N.
119 prompt "Subarchitecture Type"
125 Choose this option if your computer is a standard PC or compatible.
130 Select this for an AMD Elan processor.
132 Do not use this option for K6/Athlon/Opteron processors!
134 If unsure, choose "PC-compatible" instead.
139 Voyager is an MCA-based 32-way capable SMP architecture proprietary
140 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
144 If you do not specifically know you have a Voyager based machine,
145 say N here, otherwise the kernel you build will not be bootable.
148 bool "NUMAQ (IBM/Sequent)"
152 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
153 multiquad box. This changes the way that processors are bootstrapped,
154 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
155 You will need a new lynxer.elf file to flash your firmware with - send
156 email to <Martin.Bligh@us.ibm.com>.
159 bool "Summit/EXA (IBM x440)"
162 This option is needed for IBM systems that use the Summit/EXA chipset.
163 In particular, it is needed for the x440.
165 If you don't have one of these computers, you should say N here.
166 If you want to build a NUMA kernel, you must select ACPI.
169 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
172 This option is needed for the systems that have more than 8 CPUs
173 and if the system is not of any sub-arch type above.
175 If you don't have such a system, you should say N here.
178 bool "SGI 320/540 (Visual Workstation)"
180 The SGI Visual Workstation series is an IA32-based workstation
181 based on SGI systems chips with some legacy PC hardware attached.
183 Say Y here to create a kernel to run on the SGI 320 or 540.
185 A kernel compiled for the Visual Workstation will not run on PCs
186 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
188 config X86_GENERICARCH
189 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
191 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
192 It is intended for a generic binary kernel.
193 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
196 bool "Support for Unisys ES7000 IA32 series"
199 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
200 supposed to run on an IA32-based Unisys ES7000 system.
201 Only choose this option if you have such a system, otherwise you
207 bool "Paravirtualization support (EXPERIMENTAL)"
208 depends on EXPERIMENTAL
209 depends on !(X86_VISWS || X86_VOYAGER)
211 Paravirtualization is a way of running multiple instances of
212 Linux on the same machine, under a hypervisor. This option
213 changes the kernel so it can modify itself when it is run
214 under a hypervisor, improving performance significantly.
215 However, when run without a hypervisor the kernel is
216 theoretically slower. If in doubt, say N.
219 bool "VMI Paravirt-ops support"
220 depends on PARAVIRT && !NO_HZ
223 VMI provides a paravirtualized interface to multiple hypervisors
224 include VMware ESX server and Xen by connecting to a ROM module
225 provided by the hypervisor.
230 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
233 config HAVE_ARCH_PARSE_SRAT
238 config X86_SUMMIT_NUMA
241 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
243 config X86_CYCLONE_TIMER
246 depends on X86_SUMMIT || X86_GENERICARCH
248 config ES7000_CLUSTERED_APIC
251 depends on SMP && X86_ES7000 && MPENTIUMIII
253 source "arch/i386/Kconfig.cpu"
256 bool "HPET Timer Support"
258 This enables the use of the HPET for the kernel's internal timer.
259 HPET is the next generation timer replacing legacy 8254s.
260 You can safely choose Y here. However, HPET will only be
261 activated if the platform and the BIOS support this feature.
262 Otherwise the 8254 will be used for timing services.
264 Choose N to continue using the legacy 8254 timer.
266 config HPET_EMULATE_RTC
268 depends on HPET_TIMER && RTC=y
272 int "Maximum number of CPUs (2-255)"
275 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
278 This allows you to specify the maximum number of CPUs which this
279 kernel will support. The maximum supported value is 255 and the
280 minimum value which makes sense is 2.
282 This is purely to save memory - each supported CPU adds
283 approximately eight kilobytes to the kernel image.
286 bool "SMT (Hyperthreading) scheduler support"
289 SMT scheduler support improves the CPU scheduler's decision making
290 when dealing with Intel Pentium 4 chips with HyperThreading at a
291 cost of slightly increased overhead in some places. If unsure say
295 bool "Multi-core scheduler support"
299 Multi-core scheduler support improves the CPU scheduler's decision
300 making when dealing with multi-core CPU chips at a cost of slightly
301 increased overhead in some places. If unsure say N here.
303 source "kernel/Kconfig.preempt"
306 bool "Local APIC support on uniprocessors"
307 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
309 A local APIC (Advanced Programmable Interrupt Controller) is an
310 integrated interrupt controller in the CPU. If you have a single-CPU
311 system which has a processor with a local APIC, you can say Y here to
312 enable and use it. If you say Y here even though your machine doesn't
313 have a local APIC, then the kernel will still run with no slowdown at
314 all. The local APIC supports CPU-generated self-interrupts (timer,
315 performance counters), and the NMI watchdog which detects hard
319 bool "IO-APIC support on uniprocessors"
320 depends on X86_UP_APIC
322 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
323 SMP-capable replacement for PC-style interrupt controllers. Most
324 SMP systems and many recent uniprocessor systems have one.
326 If you have a single-CPU system with an IO-APIC, you can say Y here
327 to use it. If you say Y here even though your machine doesn't have
328 an IO-APIC, then the kernel will still run with no slowdown at all.
330 config X86_LOCAL_APIC
332 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
337 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
340 config X86_VISWS_APIC
346 bool "Machine Check Exception"
347 depends on !X86_VOYAGER
349 Machine Check Exception support allows the processor to notify the
350 kernel if it detects a problem (e.g. overheating, component failure).
351 The action the kernel takes depends on the severity of the problem,
352 ranging from a warning message on the console, to halting the machine.
353 Your processor must be a Pentium or newer to support this - check the
354 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
355 have a design flaw which leads to false MCE events - hence MCE is
356 disabled on all P5 processors, unless explicitly enabled with "mce"
357 as a boot argument. Similarly, if MCE is built in and creates a
358 problem on some new non-standard machine, you can boot with "nomce"
359 to disable it. MCE support simply ignores non-MCE processors like
360 the 386 and 486, so nearly everyone can say Y here.
362 config X86_MCE_NONFATAL
363 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
366 Enabling this feature starts a timer that triggers every 5 seconds which
367 will look at the machine check registers to see if anything happened.
368 Non-fatal problems automatically get corrected (but still logged).
369 Disable this if you don't want to see these messages.
370 Seeing the messages this option prints out may be indicative of dying hardware,
371 or out-of-spec (ie, overclocked) hardware.
372 This option only does something on certain CPUs.
373 (AMD Athlon/Duron and Intel Pentium 4)
375 config X86_MCE_P4THERMAL
376 bool "check for P4 thermal throttling interrupt."
377 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
379 Enabling this feature will cause a message to be printed when the P4
380 enters thermal throttling.
384 bool "Enable VM86 support" if EMBEDDED
386 This option is required by programs like DOSEMU to run 16-bit legacy
387 code on X86 processors. It also may be needed by software like
388 XFree86 to initialize some video cards via BIOS. Disabling this
389 option saves about 6k.
392 tristate "Toshiba Laptop support"
394 This adds a driver to safely access the System Management Mode of
395 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
396 not work on models with a Phoenix BIOS. The System Management Mode
397 is used to set the BIOS and power saving options on Toshiba portables.
399 For information on utilities to make use of this driver see the
400 Toshiba Linux utilities web site at:
401 <http://www.buzzard.org.uk/toshiba/>.
403 Say Y if you intend to run this kernel on a Toshiba portable.
407 tristate "Dell laptop support"
409 This adds a driver to safely access the System Management Mode
410 of the CPU on the Dell Inspiron 8000. The System Management Mode
411 is used to read cpu temperature and cooling fan status and to
412 control the fans on the I8K portables.
414 This driver has been tested only on the Inspiron 8000 but it may
415 also work with other Dell laptops. You can force loading on other
416 models by passing the parameter `force=1' to the module. Use at
419 For information on utilities to make use of this driver see the
420 I8K Linux utilities web site at:
421 <http://people.debian.org/~dz/i8k/>
423 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
426 config X86_REBOOTFIXUPS
427 bool "Enable X86 board specific fixups for reboot"
431 This enables chipset and/or board specific fixups to be done
432 in order to get reboot to work correctly. This is only needed on
433 some combinations of hardware and BIOS. The symptom, for which
434 this config is intended, is when reboot ends with a stalled/hung
437 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
440 Say Y if you want to enable the fixup. Currently, it's safe to
441 enable this option even if you don't need it.
445 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
448 If you say Y here and also to "/dev file system support" in the
449 'File systems' section, you will be able to update the microcode on
450 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
451 Pentium III, Pentium 4, Xeon etc. You will obviously need the
452 actual microcode binary data itself which is not shipped with the
455 For latest news and information on obtaining all the required
456 ingredients for this driver, check:
457 <http://www.urbanmyth.org/microcode/>.
459 To compile this driver as a module, choose M here: the
460 module will be called microcode.
462 config MICROCODE_OLD_INTERFACE
468 tristate "/dev/cpu/*/msr - Model-specific register support"
470 This device gives privileged processes access to the x86
471 Model-Specific Registers (MSRs). It is a character device with
472 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
473 MSR accesses are directed to a specific CPU on multi-processor
477 tristate "/dev/cpu/*/cpuid - CPU information support"
479 This device gives processes access to the x86 CPUID instruction to
480 be executed on a specific processor. It is a character device
481 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
484 source "drivers/firmware/Kconfig"
487 prompt "High Memory Support"
488 default HIGHMEM4G if !X86_NUMAQ
489 default HIGHMEM64G if X86_NUMAQ
493 depends on !X86_NUMAQ
495 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
496 However, the address space of 32-bit x86 processors is only 4
497 Gigabytes large. That means that, if you have a large amount of
498 physical memory, not all of it can be "permanently mapped" by the
499 kernel. The physical memory that's not permanently mapped is called
502 If you are compiling a kernel which will never run on a machine with
503 more than 1 Gigabyte total physical RAM, answer "off" here (default
504 choice and suitable for most users). This will result in a "3GB/1GB"
505 split: 3GB are mapped so that each process sees a 3GB virtual memory
506 space and the remaining part of the 4GB virtual memory space is used
507 by the kernel to permanently map as much physical memory as
510 If the machine has between 1 and 4 Gigabytes physical RAM, then
513 If more than 4 Gigabytes is used then answer "64GB" here. This
514 selection turns Intel PAE (Physical Address Extension) mode on.
515 PAE implements 3-level paging on IA32 processors. PAE is fully
516 supported by Linux, PAE mode is implemented on all recent Intel
517 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
518 then the kernel will not boot on CPUs that don't support PAE!
520 The actual amount of total physical memory will either be
521 auto detected or can be forced by using a kernel command line option
522 such as "mem=256M". (Try "man bootparam" or see the documentation of
523 your boot loader (lilo or loadlin) about how to pass options to the
524 kernel at boot time.)
526 If unsure, say "off".
530 depends on !X86_NUMAQ
532 Select this if you have a 32-bit processor and between 1 and 4
533 gigabytes of physical RAM.
537 depends on X86_CMPXCHG64
539 Select this if you have a 32-bit processor and more than 4
540 gigabytes of physical RAM.
545 depends on EXPERIMENTAL
546 prompt "Memory split" if EMBEDDED
549 Select the desired split between kernel and user memory.
551 If the address range available to the kernel is less than the
552 physical memory installed, the remaining memory will be available
553 as "high memory". Accessing high memory is a little more costly
554 than low memory, as it needs to be mapped into the kernel first.
555 Note that increasing the kernel address space limits the range
556 available to user programs, making the address space there
557 tighter. Selecting anything other than the default 3G/1G split
558 will also likely make your kernel incompatible with binary-only
561 If you are not absolutely sure what you are doing, leave this
565 bool "3G/1G user/kernel split"
566 config VMSPLIT_3G_OPT
568 bool "3G/1G user/kernel split (for full 1G low memory)"
570 bool "2G/2G user/kernel split"
572 bool "1G/3G user/kernel split"
577 default 0xB0000000 if VMSPLIT_3G_OPT
578 default 0x78000000 if VMSPLIT_2G
579 default 0x40000000 if VMSPLIT_1G
584 depends on HIGHMEM64G || HIGHMEM4G
589 depends on HIGHMEM64G
591 select RESOURCES_64BIT
593 # Common NUMA Features
595 bool "Numa Memory Allocation and Scheduler Support"
596 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
598 default y if (X86_NUMAQ || X86_SUMMIT)
600 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
601 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
605 default "4" if X86_NUMAQ
607 depends on NEED_MULTIPLE_NODES
609 config HAVE_ARCH_BOOTMEM_NODE
614 config ARCH_HAVE_MEMORY_PRESENT
616 depends on DISCONTIGMEM
619 config NEED_NODE_MEMMAP_SIZE
621 depends on DISCONTIGMEM || SPARSEMEM
624 config HAVE_ARCH_ALLOC_REMAP
629 config ARCH_FLATMEM_ENABLE
631 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
633 config ARCH_DISCONTIGMEM_ENABLE
637 config ARCH_DISCONTIGMEM_DEFAULT
641 config ARCH_SPARSEMEM_ENABLE
643 depends on (NUMA || (X86_PC && EXPERIMENTAL))
644 select SPARSEMEM_STATIC
646 config ARCH_SELECT_MEMORY_MODEL
648 depends on ARCH_SPARSEMEM_ENABLE
650 config ARCH_POPULATES_NODE_MAP
656 bool "Allocate 3rd-level pagetables from highmem"
657 depends on HIGHMEM4G || HIGHMEM64G
659 The VM uses one page table entry for each page of physical memory.
660 For systems with a lot of RAM, this can be wasteful of precious
661 low memory. Setting this option will put user-space page table
662 entries in high memory.
664 config MATH_EMULATION
665 bool "Math emulation"
667 Linux can emulate a math coprocessor (used for floating point
668 operations) if you don't have one. 486DX and Pentium processors have
669 a math coprocessor built in, 486SX and 386 do not, unless you added
670 a 487DX or 387, respectively. (The messages during boot time can
671 give you some hints here ["man dmesg"].) Everyone needs either a
672 coprocessor or this emulation.
674 If you don't have a math coprocessor, you need to say Y here; if you
675 say Y here even though you have a coprocessor, the coprocessor will
676 be used nevertheless. (This behavior can be changed with the kernel
677 command line option "no387", which comes handy if your coprocessor
678 is broken. Try "man bootparam" or see the documentation of your boot
679 loader (lilo or loadlin) about how to pass options to the kernel at
680 boot time.) This means that it is a good idea to say Y here if you
681 intend to use this kernel on different machines.
683 More information about the internals of the Linux math coprocessor
684 emulation can be found in <file:arch/i386/math-emu/README>.
686 If you are not sure, say Y; apart from resulting in a 66 KB bigger
687 kernel, it won't hurt.
690 bool "MTRR (Memory Type Range Register) support"
692 On Intel P6 family processors (Pentium Pro, Pentium II and later)
693 the Memory Type Range Registers (MTRRs) may be used to control
694 processor access to memory ranges. This is most useful if you have
695 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
696 allows bus write transfers to be combined into a larger transfer
697 before bursting over the PCI/AGP bus. This can increase performance
698 of image write operations 2.5 times or more. Saying Y here creates a
699 /proc/mtrr file which may be used to manipulate your processor's
700 MTRRs. Typically the X server should use this.
702 This code has a reasonably generic interface so that similar
703 control registers on other processors can be easily supported
706 The Cyrix 6x86, 6x86MX and M II processors have Address Range
707 Registers (ARRs) which provide a similar functionality to MTRRs. For
708 these, the ARRs are used to emulate the MTRRs.
709 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
710 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
711 write-combining. All of these processors are supported by this code
712 and it makes sense to say Y here if you have one of them.
714 Saying Y here also fixes a problem with buggy SMP BIOSes which only
715 set the MTRRs for the boot CPU and not for the secondary CPUs. This
716 can lead to all sorts of problems, so it's good to say Y here.
718 You can safely say Y even if your machine doesn't have MTRRs, you'll
719 just add about 9 KB to your kernel.
721 See <file:Documentation/mtrr.txt> for more information.
724 bool "Boot from EFI support"
728 This enables the kernel to boot on EFI platforms using
729 system configuration information passed to it from the firmware.
730 This also enables the kernel to use any EFI runtime services that are
731 available (such as the EFI variable services).
733 This option is only useful on systems that have EFI firmware
734 and will result in a kernel image that is ~8k larger. In addition,
735 you must use the latest ELILO loader available at
736 <http://elilo.sourceforge.net> in order to take advantage of
737 kernel initialization using EFI information (neither GRUB nor LILO know
738 anything about EFI). However, even with this option, the resultant
739 kernel should continue to boot on existing non-EFI platforms.
742 bool "Enable kernel irq balancing"
743 depends on SMP && X86_IO_APIC
746 The default yes will allow the kernel to do irq load balancing.
747 Saying no will keep the kernel from doing irq load balancing.
749 # turning this on wastes a bunch of space.
750 # Summit needs it only when NUMA is on
753 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
757 bool "Enable seccomp to safely compute untrusted bytecode"
761 This kernel feature is useful for number crunching applications
762 that may need to compute untrusted bytecode during their
763 execution. By using pipes or other transports made available to
764 the process as file descriptors supporting the read/write
765 syscalls, it's possible to isolate those applications in
766 their own address space using seccomp. Once seccomp is
767 enabled via /proc/<pid>/seccomp, it cannot be disabled
768 and the task is only allowed to execute a few safe syscalls
769 defined by each seccomp mode.
771 If unsure, say Y. Only embedded should say N here.
773 source kernel/Kconfig.hz
776 bool "kexec system call"
778 kexec is a system call that implements the ability to shutdown your
779 current kernel, and to start another kernel. It is like a reboot
780 but it is independent of the system firmware. And like a reboot
781 you can start any kernel with it, not just Linux.
783 The name comes from the similarity to the exec system call.
785 It is an ongoing process to be certain the hardware in a machine
786 is properly shutdown, so do not be surprised if this code does not
787 initially work for you. It may help to enable device hotplugging
788 support. As of this writing the exact hardware interface is
789 strongly in flux, so no good recommendation can be made.
792 bool "kernel crash dumps (EXPERIMENTAL)"
793 depends on EXPERIMENTAL
796 Generate crash dump after being started by kexec.
797 This should be normally only set in special crash dump kernels
798 which are loaded in the main kernel with kexec-tools into
799 a specially reserved region and then later executed after
800 a crash by kdump/kexec. The crash dump kernel must be compiled
801 to a memory address not used by the main kernel or BIOS using
803 For more details see Documentation/kdump/kdump.txt
805 config PHYSICAL_START
806 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
809 This gives the physical address where the kernel is loaded.
811 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
812 bzImage will decompress itself to above physical address and
813 run from there. Otherwise, bzImage will run from the address where
814 it has been loaded by the boot loader and will ignore above physical
817 In normal kdump cases one does not have to set/change this option
818 as now bzImage can be compiled as a completely relocatable image
819 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
820 address. This option is mainly useful for the folks who don't want
821 to use a bzImage for capturing the crash dump and want to use a
822 vmlinux instead. vmlinux is not relocatable hence a kernel needs
823 to be specifically compiled to run from a specific memory area
824 (normally a reserved region) and this option comes handy.
826 So if you are using bzImage for capturing the crash dump, leave
827 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
828 Otherwise if you plan to use vmlinux for capturing the crash dump
829 change this value to start of the reserved region (Typically 16MB
830 0x1000000). In other words, it can be set based on the "X" value as
831 specified in the "crashkernel=YM@XM" command line boot parameter
832 passed to the panic-ed kernel. Typically this parameter is set as
833 crashkernel=64M@16M. Please take a look at
834 Documentation/kdump/kdump.txt for more details about crash dumps.
836 Usage of bzImage for capturing the crash dump is recommended as
837 one does not have to build two kernels. Same kernel can be used
838 as production kernel and capture kernel. Above option should have
839 gone away after relocatable bzImage support is introduced. But it
840 is present because there are users out there who continue to use
841 vmlinux for dump capture. This option should go away down the
844 Don't change this unless you know what you are doing.
847 bool "Build a relocatable kernel(EXPERIMENTAL)"
848 depends on EXPERIMENTAL
850 This build a kernel image that retains relocation information
851 so it can be loaded someplace besides the default 1MB.
852 The relocations tend to the kernel binary about 10% larger,
853 but are discarded at runtime.
855 One use is for the kexec on panic case where the recovery kernel
856 must live at a different physical address than the primary
859 config PHYSICAL_ALIGN
860 hex "Alignment value to which kernel should be aligned"
862 range 0x2000 0x400000
864 This value puts the alignment restrictions on physical address
865 where kernel is loaded and run from. Kernel is compiled for an
866 address which meets above alignment restriction.
868 If bootloader loads the kernel at a non-aligned address and
869 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
870 address aligned to above value and run from there.
872 If bootloader loads the kernel at a non-aligned address and
873 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
874 load address and decompress itself to the address it has been
875 compiled for and run from there. The address for which kernel is
876 compiled already meets above alignment restrictions. Hence the
877 end result is that kernel runs from a physical address meeting
878 above alignment restrictions.
880 Don't change this unless you know what you are doing.
883 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
884 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
886 Say Y here to experiment with turning CPUs off and on, and to
887 enable suspend on SMP systems. CPUs can be controlled through
888 /sys/devices/system/cpu.
891 bool "Compat VDSO support"
895 Map the VDSO to the predictable old-style address too.
897 Say N here if you are running a sufficiently recent glibc
898 version (2.3.3 or later), to remove the high-mapped
899 VDSO mapping and to exclusively use the randomized VDSO.
905 config ARCH_ENABLE_MEMORY_HOTPLUG
909 menu "Power management options (ACPI, APM)"
910 depends on !X86_VOYAGER
912 source kernel/power/Kconfig
914 source "drivers/acpi/Kconfig"
916 menu "APM (Advanced Power Management) BIOS Support"
917 depends on PM && !X86_VISWS
920 tristate "APM (Advanced Power Management) BIOS support"
923 APM is a BIOS specification for saving power using several different
924 techniques. This is mostly useful for battery powered laptops with
925 APM compliant BIOSes. If you say Y here, the system time will be
926 reset after a RESUME operation, the /proc/apm device will provide
927 battery status information, and user-space programs will receive
928 notification of APM "events" (e.g. battery status change).
930 If you select "Y" here, you can disable actual use of the APM
931 BIOS by passing the "apm=off" option to the kernel at boot time.
933 Note that the APM support is almost completely disabled for
934 machines with more than one CPU.
936 In order to use APM, you will need supporting software. For location
937 and more information, read <file:Documentation/pm.txt> and the
938 Battery Powered Linux mini-HOWTO, available from
939 <http://www.tldp.org/docs.html#howto>.
941 This driver does not spin down disk drives (see the hdparm(8)
942 manpage ("man 8 hdparm") for that), and it doesn't turn off
943 VESA-compliant "green" monitors.
945 This driver does not support the TI 4000M TravelMate and the ACER
946 486/DX4/75 because they don't have compliant BIOSes. Many "green"
947 desktop machines also don't have compliant BIOSes, and this driver
948 may cause those machines to panic during the boot phase.
950 Generally, if you don't have a battery in your machine, there isn't
951 much point in using this driver and you should say N. If you get
952 random kernel OOPSes or reboots that don't seem to be related to
953 anything, try disabling/enabling this option (or disabling/enabling
956 Some other things you should try when experiencing seemingly random,
959 1) make sure that you have enough swap space and that it is
961 2) pass the "no-hlt" option to the kernel
962 3) switch on floating point emulation in the kernel and pass
963 the "no387" option to the kernel
964 4) pass the "floppy=nodma" option to the kernel
965 5) pass the "mem=4M" option to the kernel (thereby disabling
966 all but the first 4 MB of RAM)
967 6) make sure that the CPU is not over clocked.
968 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
969 8) disable the cache from your BIOS settings
970 9) install a fan for the video card or exchange video RAM
971 10) install a better fan for the CPU
972 11) exchange RAM chips
973 12) exchange the motherboard.
975 To compile this driver as a module, choose M here: the
976 module will be called apm.
978 config APM_IGNORE_USER_SUSPEND
979 bool "Ignore USER SUSPEND"
982 This option will ignore USER SUSPEND requests. On machines with a
983 compliant APM BIOS, you want to say N. However, on the NEC Versa M
984 series notebooks, it is necessary to say Y because of a BIOS bug.
987 bool "Enable PM at boot time"
990 Enable APM features at boot time. From page 36 of the APM BIOS
991 specification: "When disabled, the APM BIOS does not automatically
992 power manage devices, enter the Standby State, enter the Suspend
993 State, or take power saving steps in response to CPU Idle calls."
994 This driver will make CPU Idle calls when Linux is idle (unless this
995 feature is turned off -- see "Do CPU IDLE calls", below). This
996 should always save battery power, but more complicated APM features
997 will be dependent on your BIOS implementation. You may need to turn
998 this option off if your computer hangs at boot time when using APM
999 support, or if it beeps continuously instead of suspending. Turn
1000 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1001 T400CDT. This is off by default since most machines do fine without
1005 bool "Make CPU Idle calls when idle"
1008 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1009 On some machines, this can activate improved power savings, such as
1010 a slowed CPU clock rate, when the machine is idle. These idle calls
1011 are made after the idle loop has run for some length of time (e.g.,
1012 333 mS). On some machines, this will cause a hang at boot time or
1013 whenever the CPU becomes idle. (On machines with more than one CPU,
1014 this option does nothing.)
1016 config APM_DISPLAY_BLANK
1017 bool "Enable console blanking using APM"
1020 Enable console blanking using the APM. Some laptops can use this to
1021 turn off the LCD backlight when the screen blanker of the Linux
1022 virtual console blanks the screen. Note that this is only used by
1023 the virtual console screen blanker, and won't turn off the backlight
1024 when using the X Window system. This also doesn't have anything to
1025 do with your VESA-compliant power-saving monitor. Further, this
1026 option doesn't work for all laptops -- it might not turn off your
1027 backlight at all, or it might print a lot of errors to the console,
1028 especially if you are using gpm.
1030 config APM_RTC_IS_GMT
1031 bool "RTC stores time in GMT"
1034 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1035 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1038 It is in fact recommended to store GMT in your RTC, because then you
1039 don't have to worry about daylight savings time changes. The only
1040 reason not to use GMT in your RTC is if you also run a broken OS
1041 that doesn't understand GMT.
1043 config APM_ALLOW_INTS
1044 bool "Allow interrupts during APM BIOS calls"
1047 Normally we disable external interrupts while we are making calls to
1048 the APM BIOS as a measure to lessen the effects of a badly behaving
1049 BIOS implementation. The BIOS should reenable interrupts if it
1050 needs to. Unfortunately, some BIOSes do not -- especially those in
1051 many of the newer IBM Thinkpads. If you experience hangs when you
1052 suspend, try setting this to Y. Otherwise, say N.
1054 config APM_REAL_MODE_POWER_OFF
1055 bool "Use real mode APM BIOS call to power off"
1058 Use real mode APM BIOS calls to switch off the computer. This is
1059 a work-around for a number of buggy BIOSes. Switch this option on if
1060 your computer crashes instead of powering off properly.
1064 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1068 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1071 bool "PCI support" if !X86_VISWS
1072 depends on !X86_VOYAGER
1073 default y if X86_VISWS
1075 Find out whether you have a PCI motherboard. PCI is the name of a
1076 bus system, i.e. the way the CPU talks to the other stuff inside
1077 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1078 VESA. If you have PCI, say Y, otherwise N.
1080 The PCI-HOWTO, available from
1081 <http://www.tldp.org/docs.html#howto>, contains valuable
1082 information about which PCI hardware does work under Linux and which
1086 prompt "PCI access mode"
1087 depends on PCI && !X86_VISWS
1090 On PCI systems, the BIOS can be used to detect the PCI devices and
1091 determine their configuration. However, some old PCI motherboards
1092 have BIOS bugs and may crash if this is done. Also, some embedded
1093 PCI-based systems don't have any BIOS at all. Linux can also try to
1094 detect the PCI hardware directly without using the BIOS.
1096 With this option, you can specify how Linux should detect the
1097 PCI devices. If you choose "BIOS", the BIOS will be used,
1098 if you choose "Direct", the BIOS won't be used, and if you
1099 choose "MMConfig", then PCI Express MMCONFIG will be used.
1100 If you choose "Any", the kernel will try MMCONFIG, then the
1101 direct access method and falls back to the BIOS if that doesn't
1102 work. If unsure, go with the default, which is "Any".
1107 config PCI_GOMMCONFIG
1120 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1125 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1130 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1133 source "drivers/pci/pcie/Kconfig"
1135 source "drivers/pci/Kconfig"
1143 depends on !(X86_VOYAGER || X86_VISWS)
1145 Find out whether you have ISA slots on your motherboard. ISA is the
1146 name of a bus system, i.e. the way the CPU talks to the other stuff
1147 inside your box. Other bus systems are PCI, EISA, MicroChannel
1148 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1149 newer boards don't support it. If you have ISA, say Y, otherwise N.
1155 The Extended Industry Standard Architecture (EISA) bus was
1156 developed as an open alternative to the IBM MicroChannel bus.
1158 The EISA bus provided some of the features of the IBM MicroChannel
1159 bus while maintaining backward compatibility with cards made for
1160 the older ISA bus. The EISA bus saw limited use between 1988 and
1161 1995 when it was made obsolete by the PCI bus.
1163 Say Y here if you are building a kernel for an EISA-based machine.
1167 source "drivers/eisa/Kconfig"
1170 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1171 default y if X86_VOYAGER
1173 MicroChannel Architecture is found in some IBM PS/2 machines and
1174 laptops. It is a bus system similar to PCI or ISA. See
1175 <file:Documentation/mca.txt> (and especially the web page given
1176 there) before attempting to build an MCA bus kernel.
1178 source "drivers/mca/Kconfig"
1181 tristate "NatSemi SCx200 support"
1182 depends on !X86_VOYAGER
1184 This provides basic support for National Semiconductor's
1185 (now AMD's) Geode processors. The driver probes for the
1186 PCI-IDs of several on-chip devices, so its a good dependency
1187 for other scx200_* drivers.
1189 If compiled as a module, the driver is named scx200.
1191 config SCx200HR_TIMER
1192 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1193 depends on SCx200 && GENERIC_TIME
1196 This driver provides a clocksource built upon the on-chip
1197 27MHz high-resolution timer. Its also a workaround for
1198 NSC Geode SC-1100's buggy TSC, which loses time when the
1199 processor goes idle (as is done by the scheduler). The
1200 other workaround is idle=poll boot option.
1204 depends on AGP_AMD64
1206 source "drivers/pcmcia/Kconfig"
1208 source "drivers/pci/hotplug/Kconfig"
1212 menu "Executable file formats"
1214 source "fs/Kconfig.binfmt"
1218 source "net/Kconfig"
1220 source "drivers/Kconfig"
1224 menu "Instrumentation Support"
1225 depends on EXPERIMENTAL
1227 source "arch/i386/oprofile/Kconfig"
1230 bool "Kprobes (EXPERIMENTAL)"
1231 depends on KALLSYMS && EXPERIMENTAL && MODULES
1233 Kprobes allows you to trap at almost any kernel address and
1234 execute a callback function. register_kprobe() establishes
1235 a probepoint and specifies the callback. Kprobes is useful
1236 for kernel debugging, non-intrusive instrumentation and testing.
1237 If in doubt, say "N".
1240 source "arch/i386/Kconfig.debug"
1242 source "security/Kconfig"
1244 source "crypto/Kconfig"
1246 source "lib/Kconfig"
1249 # Use the generic interrupt handling code in kernel/irq/:
1251 config GENERIC_HARDIRQS
1255 config GENERIC_IRQ_PROBE
1259 config GENERIC_PENDING_IRQ
1261 depends on GENERIC_HARDIRQS && SMP
1266 depends on SMP && !X86_VOYAGER
1271 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1274 config X86_BIOS_REBOOT
1276 depends on !(X86_VISWS || X86_VOYAGER)
1279 config X86_TRAMPOLINE
1281 depends on X86_SMP || (X86_VOYAGER && SMP)
1293 Switches the regular HZ timer off when the system is going idle.
1294 This helps a hypervisor detect that the Linux system is idle,
1295 reducing the overhead of idle systems.
git.samba.org / sfrench / cifs-2.6.git / blob