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 LOCKDEP_SUPPORT
25 config STACKTRACE_SUPPORT
29 config SEMAPHORE_SLEEPERS
44 config GENERIC_ISA_DMA
57 config GENERIC_HWEIGHT
61 config ARCH_MAY_HAVE_PC_FDC
71 menu "Processor type and features"
74 bool "Symmetric multi-processing support"
76 This enables support for systems with more than one CPU. If you have
77 a system with only one CPU, like most personal computers, say N. If
78 you have a system with more than one CPU, say Y.
80 If you say N here, the kernel will run on single and multiprocessor
81 machines, but will use only one CPU of a multiprocessor machine. If
82 you say Y here, the kernel will run on many, but not all,
83 singleprocessor machines. On a singleprocessor machine, the kernel
84 will run faster if you say N here.
86 Note that if you say Y here and choose architecture "586" or
87 "Pentium" under "Processor family", the kernel will not work on 486
88 architectures. Similarly, multiprocessor kernels for the "PPro"
89 architecture may not work on all Pentium based boards.
91 People using multiprocessor machines who say Y here should also say
92 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
93 Management" code will be disabled if you say Y here.
95 See also the <file:Documentation/smp.txt>,
96 <file:Documentation/i386/IO-APIC.txt>,
97 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
98 <http://www.tldp.org/docs.html#howto>.
100 If you don't know what to do here, say N.
103 prompt "Subarchitecture Type"
109 Choose this option if your computer is a standard PC or compatible.
114 Select this for an AMD Elan processor.
116 Do not use this option for K6/Athlon/Opteron processors!
118 If unsure, choose "PC-compatible" instead.
123 Voyager is an MCA-based 32-way capable SMP architecture proprietary
124 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
128 If you do not specifically know you have a Voyager based machine,
129 say N here, otherwise the kernel you build will not be bootable.
132 bool "NUMAQ (IBM/Sequent)"
136 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
137 multiquad box. This changes the way that processors are bootstrapped,
138 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
139 You will need a new lynxer.elf file to flash your firmware with - send
140 email to <Martin.Bligh@us.ibm.com>.
143 bool "Summit/EXA (IBM x440)"
146 This option is needed for IBM systems that use the Summit/EXA chipset.
147 In particular, it is needed for the x440.
149 If you don't have one of these computers, you should say N here.
150 If you want to build a NUMA kernel, you must select ACPI.
153 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
156 This option is needed for the systems that have more than 8 CPUs
157 and if the system is not of any sub-arch type above.
159 If you don't have such a system, you should say N here.
162 bool "SGI 320/540 (Visual Workstation)"
164 The SGI Visual Workstation series is an IA32-based workstation
165 based on SGI systems chips with some legacy PC hardware attached.
167 Say Y here to create a kernel to run on the SGI 320 or 540.
169 A kernel compiled for the Visual Workstation will not run on PCs
170 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
172 config X86_GENERICARCH
173 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
175 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
176 It is intended for a generic binary kernel.
177 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
180 bool "Support for Unisys ES7000 IA32 series"
183 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
184 supposed to run on an IA32-based Unisys ES7000 system.
185 Only choose this option if you have such a system, otherwise you
191 bool "Paravirtualization support (EXPERIMENTAL)"
192 depends on EXPERIMENTAL
193 depends on !(X86_VISWS || X86_VOYAGER)
195 Paravirtualization is a way of running multiple instances of
196 Linux on the same machine, under a hypervisor. This option
197 changes the kernel so it can modify itself when it is run
198 under a hypervisor, improving performance significantly.
199 However, when run without a hypervisor the kernel is
200 theoretically slower. If in doubt, say N.
205 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
208 config HAVE_ARCH_PARSE_SRAT
213 config X86_SUMMIT_NUMA
216 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
218 config X86_CYCLONE_TIMER
221 depends on X86_SUMMIT || X86_GENERICARCH
223 config ES7000_CLUSTERED_APIC
226 depends on SMP && X86_ES7000 && MPENTIUMIII
228 source "arch/i386/Kconfig.cpu"
231 bool "HPET Timer Support"
233 This enables the use of the HPET for the kernel's internal timer.
234 HPET is the next generation timer replacing legacy 8254s.
235 You can safely choose Y here. However, HPET will only be
236 activated if the platform and the BIOS support this feature.
237 Otherwise the 8254 will be used for timing services.
239 Choose N to continue using the legacy 8254 timer.
241 config HPET_EMULATE_RTC
243 depends on HPET_TIMER && RTC=y
247 int "Maximum number of CPUs (2-255)"
250 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
253 This allows you to specify the maximum number of CPUs which this
254 kernel will support. The maximum supported value is 255 and the
255 minimum value which makes sense is 2.
257 This is purely to save memory - each supported CPU adds
258 approximately eight kilobytes to the kernel image.
261 bool "SMT (Hyperthreading) scheduler support"
264 SMT scheduler support improves the CPU scheduler's decision making
265 when dealing with Intel Pentium 4 chips with HyperThreading at a
266 cost of slightly increased overhead in some places. If unsure say
270 bool "Multi-core scheduler support"
274 Multi-core scheduler support improves the CPU scheduler's decision
275 making when dealing with multi-core CPU chips at a cost of slightly
276 increased overhead in some places. If unsure say N here.
278 source "kernel/Kconfig.preempt"
281 bool "Local APIC support on uniprocessors"
282 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
284 A local APIC (Advanced Programmable Interrupt Controller) is an
285 integrated interrupt controller in the CPU. If you have a single-CPU
286 system which has a processor with a local APIC, you can say Y here to
287 enable and use it. If you say Y here even though your machine doesn't
288 have a local APIC, then the kernel will still run with no slowdown at
289 all. The local APIC supports CPU-generated self-interrupts (timer,
290 performance counters), and the NMI watchdog which detects hard
294 bool "IO-APIC support on uniprocessors"
295 depends on X86_UP_APIC
297 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
298 SMP-capable replacement for PC-style interrupt controllers. Most
299 SMP systems and many recent uniprocessor systems have one.
301 If you have a single-CPU system with an IO-APIC, you can say Y here
302 to use it. If you say Y here even though your machine doesn't have
303 an IO-APIC, then the kernel will still run with no slowdown at all.
305 config X86_LOCAL_APIC
307 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
312 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
315 config X86_VISWS_APIC
321 bool "Machine Check Exception"
322 depends on !X86_VOYAGER
324 Machine Check Exception support allows the processor to notify the
325 kernel if it detects a problem (e.g. overheating, component failure).
326 The action the kernel takes depends on the severity of the problem,
327 ranging from a warning message on the console, to halting the machine.
328 Your processor must be a Pentium or newer to support this - check the
329 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
330 have a design flaw which leads to false MCE events - hence MCE is
331 disabled on all P5 processors, unless explicitly enabled with "mce"
332 as a boot argument. Similarly, if MCE is built in and creates a
333 problem on some new non-standard machine, you can boot with "nomce"
334 to disable it. MCE support simply ignores non-MCE processors like
335 the 386 and 486, so nearly everyone can say Y here.
337 config X86_MCE_NONFATAL
338 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
341 Enabling this feature starts a timer that triggers every 5 seconds which
342 will look at the machine check registers to see if anything happened.
343 Non-fatal problems automatically get corrected (but still logged).
344 Disable this if you don't want to see these messages.
345 Seeing the messages this option prints out may be indicative of dying hardware,
346 or out-of-spec (ie, overclocked) hardware.
347 This option only does something on certain CPUs.
348 (AMD Athlon/Duron and Intel Pentium 4)
350 config X86_MCE_P4THERMAL
351 bool "check for P4 thermal throttling interrupt."
352 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
354 Enabling this feature will cause a message to be printed when the P4
355 enters thermal throttling.
359 bool "Enable VM86 support" if EMBEDDED
361 This option is required by programs like DOSEMU to run 16-bit legacy
362 code on X86 processors. It also may be needed by software like
363 XFree86 to initialize some video cards via BIOS. Disabling this
364 option saves about 6k.
367 tristate "Toshiba Laptop support"
369 This adds a driver to safely access the System Management Mode of
370 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
371 not work on models with a Phoenix BIOS. The System Management Mode
372 is used to set the BIOS and power saving options on Toshiba portables.
374 For information on utilities to make use of this driver see the
375 Toshiba Linux utilities web site at:
376 <http://www.buzzard.org.uk/toshiba/>.
378 Say Y if you intend to run this kernel on a Toshiba portable.
382 tristate "Dell laptop support"
384 This adds a driver to safely access the System Management Mode
385 of the CPU on the Dell Inspiron 8000. The System Management Mode
386 is used to read cpu temperature and cooling fan status and to
387 control the fans on the I8K portables.
389 This driver has been tested only on the Inspiron 8000 but it may
390 also work with other Dell laptops. You can force loading on other
391 models by passing the parameter `force=1' to the module. Use at
394 For information on utilities to make use of this driver see the
395 I8K Linux utilities web site at:
396 <http://people.debian.org/~dz/i8k/>
398 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
401 config X86_REBOOTFIXUPS
402 bool "Enable X86 board specific fixups for reboot"
406 This enables chipset and/or board specific fixups to be done
407 in order to get reboot to work correctly. This is only needed on
408 some combinations of hardware and BIOS. The symptom, for which
409 this config is intended, is when reboot ends with a stalled/hung
412 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
415 Say Y if you want to enable the fixup. Currently, it's safe to
416 enable this option even if you don't need it.
420 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
423 If you say Y here and also to "/dev file system support" in the
424 'File systems' section, you will be able to update the microcode on
425 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
426 Pentium III, Pentium 4, Xeon etc. You will obviously need the
427 actual microcode binary data itself which is not shipped with the
430 For latest news and information on obtaining all the required
431 ingredients for this driver, check:
432 <http://www.urbanmyth.org/microcode/>.
434 To compile this driver as a module, choose M here: the
435 module will be called microcode.
437 config MICROCODE_OLD_INTERFACE
443 tristate "/dev/cpu/*/msr - Model-specific register support"
445 This device gives privileged processes access to the x86
446 Model-Specific Registers (MSRs). It is a character device with
447 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
448 MSR accesses are directed to a specific CPU on multi-processor
452 tristate "/dev/cpu/*/cpuid - CPU information support"
454 This device gives processes access to the x86 CPUID instruction to
455 be executed on a specific processor. It is a character device
456 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
459 source "drivers/firmware/Kconfig"
462 prompt "High Memory Support"
463 default HIGHMEM4G if !X86_NUMAQ
464 default HIGHMEM64G if X86_NUMAQ
468 depends on !X86_NUMAQ
470 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
471 However, the address space of 32-bit x86 processors is only 4
472 Gigabytes large. That means that, if you have a large amount of
473 physical memory, not all of it can be "permanently mapped" by the
474 kernel. The physical memory that's not permanently mapped is called
477 If you are compiling a kernel which will never run on a machine with
478 more than 1 Gigabyte total physical RAM, answer "off" here (default
479 choice and suitable for most users). This will result in a "3GB/1GB"
480 split: 3GB are mapped so that each process sees a 3GB virtual memory
481 space and the remaining part of the 4GB virtual memory space is used
482 by the kernel to permanently map as much physical memory as
485 If the machine has between 1 and 4 Gigabytes physical RAM, then
488 If more than 4 Gigabytes is used then answer "64GB" here. This
489 selection turns Intel PAE (Physical Address Extension) mode on.
490 PAE implements 3-level paging on IA32 processors. PAE is fully
491 supported by Linux, PAE mode is implemented on all recent Intel
492 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
493 then the kernel will not boot on CPUs that don't support PAE!
495 The actual amount of total physical memory will either be
496 auto detected or can be forced by using a kernel command line option
497 such as "mem=256M". (Try "man bootparam" or see the documentation of
498 your boot loader (lilo or loadlin) about how to pass options to the
499 kernel at boot time.)
501 If unsure, say "off".
505 depends on !X86_NUMAQ
507 Select this if you have a 32-bit processor and between 1 and 4
508 gigabytes of physical RAM.
512 depends on X86_CMPXCHG64
514 Select this if you have a 32-bit processor and more than 4
515 gigabytes of physical RAM.
520 depends on EXPERIMENTAL
521 prompt "Memory split" if EMBEDDED
524 Select the desired split between kernel and user memory.
526 If the address range available to the kernel is less than the
527 physical memory installed, the remaining memory will be available
528 as "high memory". Accessing high memory is a little more costly
529 than low memory, as it needs to be mapped into the kernel first.
530 Note that increasing the kernel address space limits the range
531 available to user programs, making the address space there
532 tighter. Selecting anything other than the default 3G/1G split
533 will also likely make your kernel incompatible with binary-only
536 If you are not absolutely sure what you are doing, leave this
540 bool "3G/1G user/kernel split"
541 config VMSPLIT_3G_OPT
543 bool "3G/1G user/kernel split (for full 1G low memory)"
545 bool "2G/2G user/kernel split"
547 bool "1G/3G user/kernel split"
552 default 0xB0000000 if VMSPLIT_3G_OPT
553 default 0x78000000 if VMSPLIT_2G
554 default 0x40000000 if VMSPLIT_1G
559 depends on HIGHMEM64G || HIGHMEM4G
564 depends on HIGHMEM64G
566 select RESOURCES_64BIT
568 # Common NUMA Features
570 bool "Numa Memory Allocation and Scheduler Support"
571 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
573 default y if (X86_NUMAQ || X86_SUMMIT)
575 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
576 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
580 default "4" if X86_NUMAQ
582 depends on NEED_MULTIPLE_NODES
584 config HAVE_ARCH_BOOTMEM_NODE
589 config ARCH_HAVE_MEMORY_PRESENT
591 depends on DISCONTIGMEM
594 config NEED_NODE_MEMMAP_SIZE
596 depends on DISCONTIGMEM || SPARSEMEM
599 config HAVE_ARCH_ALLOC_REMAP
604 config ARCH_FLATMEM_ENABLE
606 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
608 config ARCH_DISCONTIGMEM_ENABLE
612 config ARCH_DISCONTIGMEM_DEFAULT
616 config ARCH_SPARSEMEM_ENABLE
618 depends on (NUMA || (X86_PC && EXPERIMENTAL))
619 select SPARSEMEM_STATIC
621 config ARCH_SELECT_MEMORY_MODEL
623 depends on ARCH_SPARSEMEM_ENABLE
625 config ARCH_POPULATES_NODE_MAP
631 bool "Allocate 3rd-level pagetables from highmem"
632 depends on HIGHMEM4G || HIGHMEM64G
634 The VM uses one page table entry for each page of physical memory.
635 For systems with a lot of RAM, this can be wasteful of precious
636 low memory. Setting this option will put user-space page table
637 entries in high memory.
639 config MATH_EMULATION
640 bool "Math emulation"
642 Linux can emulate a math coprocessor (used for floating point
643 operations) if you don't have one. 486DX and Pentium processors have
644 a math coprocessor built in, 486SX and 386 do not, unless you added
645 a 487DX or 387, respectively. (The messages during boot time can
646 give you some hints here ["man dmesg"].) Everyone needs either a
647 coprocessor or this emulation.
649 If you don't have a math coprocessor, you need to say Y here; if you
650 say Y here even though you have a coprocessor, the coprocessor will
651 be used nevertheless. (This behavior can be changed with the kernel
652 command line option "no387", which comes handy if your coprocessor
653 is broken. Try "man bootparam" or see the documentation of your boot
654 loader (lilo or loadlin) about how to pass options to the kernel at
655 boot time.) This means that it is a good idea to say Y here if you
656 intend to use this kernel on different machines.
658 More information about the internals of the Linux math coprocessor
659 emulation can be found in <file:arch/i386/math-emu/README>.
661 If you are not sure, say Y; apart from resulting in a 66 KB bigger
662 kernel, it won't hurt.
665 bool "MTRR (Memory Type Range Register) support"
667 On Intel P6 family processors (Pentium Pro, Pentium II and later)
668 the Memory Type Range Registers (MTRRs) may be used to control
669 processor access to memory ranges. This is most useful if you have
670 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
671 allows bus write transfers to be combined into a larger transfer
672 before bursting over the PCI/AGP bus. This can increase performance
673 of image write operations 2.5 times or more. Saying Y here creates a
674 /proc/mtrr file which may be used to manipulate your processor's
675 MTRRs. Typically the X server should use this.
677 This code has a reasonably generic interface so that similar
678 control registers on other processors can be easily supported
681 The Cyrix 6x86, 6x86MX and M II processors have Address Range
682 Registers (ARRs) which provide a similar functionality to MTRRs. For
683 these, the ARRs are used to emulate the MTRRs.
684 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
685 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
686 write-combining. All of these processors are supported by this code
687 and it makes sense to say Y here if you have one of them.
689 Saying Y here also fixes a problem with buggy SMP BIOSes which only
690 set the MTRRs for the boot CPU and not for the secondary CPUs. This
691 can lead to all sorts of problems, so it's good to say Y here.
693 You can safely say Y even if your machine doesn't have MTRRs, you'll
694 just add about 9 KB to your kernel.
696 See <file:Documentation/mtrr.txt> for more information.
699 bool "Boot from EFI support"
703 This enables the kernel to boot on EFI platforms using
704 system configuration information passed to it from the firmware.
705 This also enables the kernel to use any EFI runtime services that are
706 available (such as the EFI variable services).
708 This option is only useful on systems that have EFI firmware
709 and will result in a kernel image that is ~8k larger. In addition,
710 you must use the latest ELILO loader available at
711 <http://elilo.sourceforge.net> in order to take advantage of
712 kernel initialization using EFI information (neither GRUB nor LILO know
713 anything about EFI). However, even with this option, the resultant
714 kernel should continue to boot on existing non-EFI platforms.
717 bool "Enable kernel irq balancing"
718 depends on SMP && X86_IO_APIC
721 The default yes will allow the kernel to do irq load balancing.
722 Saying no will keep the kernel from doing irq load balancing.
724 # turning this on wastes a bunch of space.
725 # Summit needs it only when NUMA is on
728 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
732 bool "Enable seccomp to safely compute untrusted bytecode"
736 This kernel feature is useful for number crunching applications
737 that may need to compute untrusted bytecode during their
738 execution. By using pipes or other transports made available to
739 the process as file descriptors supporting the read/write
740 syscalls, it's possible to isolate those applications in
741 their own address space using seccomp. Once seccomp is
742 enabled via /proc/<pid>/seccomp, it cannot be disabled
743 and the task is only allowed to execute a few safe syscalls
744 defined by each seccomp mode.
746 If unsure, say Y. Only embedded should say N here.
748 source kernel/Kconfig.hz
751 bool "kexec system call"
753 kexec is a system call that implements the ability to shutdown your
754 current kernel, and to start another kernel. It is like a reboot
755 but it is independent of the system firmware. And like a reboot
756 you can start any kernel with it, not just Linux.
758 The name comes from the similarity to the exec system call.
760 It is an ongoing process to be certain the hardware in a machine
761 is properly shutdown, so do not be surprised if this code does not
762 initially work for you. It may help to enable device hotplugging
763 support. As of this writing the exact hardware interface is
764 strongly in flux, so no good recommendation can be made.
767 bool "kernel crash dumps (EXPERIMENTAL)"
768 depends on EXPERIMENTAL
771 Generate crash dump after being started by kexec.
772 This should be normally only set in special crash dump kernels
773 which are loaded in the main kernel with kexec-tools into
774 a specially reserved region and then later executed after
775 a crash by kdump/kexec. The crash dump kernel must be compiled
776 to a memory address not used by the main kernel or BIOS using
778 For more details see Documentation/kdump/kdump.txt
780 config PHYSICAL_START
781 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
784 This gives the physical address where the kernel is loaded.
786 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
787 bzImage will decompress itself to above physical address and
788 run from there. Otherwise, bzImage will run from the address where
789 it has been loaded by the boot loader and will ignore above physical
792 In normal kdump cases one does not have to set/change this option
793 as now bzImage can be compiled as a completely relocatable image
794 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
795 address. This option is mainly useful for the folks who don't want
796 to use a bzImage for capturing the crash dump and want to use a
797 vmlinux instead. vmlinux is not relocatable hence a kernel needs
798 to be specifically compiled to run from a specific memory area
799 (normally a reserved region) and this option comes handy.
801 So if you are using bzImage for capturing the crash dump, leave
802 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
803 Otherwise if you plan to use vmlinux for capturing the crash dump
804 change this value to start of the reserved region (Typically 16MB
805 0x1000000). In other words, it can be set based on the "X" value as
806 specified in the "crashkernel=YM@XM" command line boot parameter
807 passed to the panic-ed kernel. Typically this parameter is set as
808 crashkernel=64M@16M. Please take a look at
809 Documentation/kdump/kdump.txt for more details about crash dumps.
811 Usage of bzImage for capturing the crash dump is recommended as
812 one does not have to build two kernels. Same kernel can be used
813 as production kernel and capture kernel. Above option should have
814 gone away after relocatable bzImage support is introduced. But it
815 is present because there are users out there who continue to use
816 vmlinux for dump capture. This option should go away down the
819 Don't change this unless you know what you are doing.
822 bool "Build a relocatable kernel(EXPERIMENTAL)"
823 depends on EXPERIMENTAL
825 This build a kernel image that retains relocation information
826 so it can be loaded someplace besides the default 1MB.
827 The relocations tend to the kernel binary about 10% larger,
828 but are discarded at runtime.
830 One use is for the kexec on panic case where the recovery kernel
831 must live at a different physical address than the primary
834 config PHYSICAL_ALIGN
835 hex "Alignment value to which kernel should be aligned"
837 range 0x2000 0x400000
839 This value puts the alignment restrictions on physical address
840 where kernel is loaded and run from. Kernel is compiled for an
841 address which meets above alignment restriction.
843 If bootloader loads the kernel at a non-aligned address and
844 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
845 address aligned to above value and run from there.
847 If bootloader loads the kernel at a non-aligned address and
848 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
849 load address and decompress itself to the address it has been
850 compiled for and run from there. The address for which kernel is
851 compiled already meets above alignment restrictions. Hence the
852 end result is that kernel runs from a physical address meeting
853 above alignment restrictions.
855 Don't change this unless you know what you are doing.
858 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
859 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
861 Say Y here to experiment with turning CPUs off and on, and to
862 enable suspend on SMP systems. CPUs can be controlled through
863 /sys/devices/system/cpu.
866 bool "Compat VDSO support"
870 Map the VDSO to the predictable old-style address too.
872 Say N here if you are running a sufficiently recent glibc
873 version (2.3.3 or later), to remove the high-mapped
874 VDSO mapping and to exclusively use the randomized VDSO.
880 config ARCH_ENABLE_MEMORY_HOTPLUG
884 menu "Power management options (ACPI, APM)"
885 depends on !X86_VOYAGER
887 source kernel/power/Kconfig
889 source "drivers/acpi/Kconfig"
891 menu "APM (Advanced Power Management) BIOS Support"
892 depends on PM && !X86_VISWS
895 tristate "APM (Advanced Power Management) BIOS support"
898 APM is a BIOS specification for saving power using several different
899 techniques. This is mostly useful for battery powered laptops with
900 APM compliant BIOSes. If you say Y here, the system time will be
901 reset after a RESUME operation, the /proc/apm device will provide
902 battery status information, and user-space programs will receive
903 notification of APM "events" (e.g. battery status change).
905 If you select "Y" here, you can disable actual use of the APM
906 BIOS by passing the "apm=off" option to the kernel at boot time.
908 Note that the APM support is almost completely disabled for
909 machines with more than one CPU.
911 In order to use APM, you will need supporting software. For location
912 and more information, read <file:Documentation/pm.txt> and the
913 Battery Powered Linux mini-HOWTO, available from
914 <http://www.tldp.org/docs.html#howto>.
916 This driver does not spin down disk drives (see the hdparm(8)
917 manpage ("man 8 hdparm") for that), and it doesn't turn off
918 VESA-compliant "green" monitors.
920 This driver does not support the TI 4000M TravelMate and the ACER
921 486/DX4/75 because they don't have compliant BIOSes. Many "green"
922 desktop machines also don't have compliant BIOSes, and this driver
923 may cause those machines to panic during the boot phase.
925 Generally, if you don't have a battery in your machine, there isn't
926 much point in using this driver and you should say N. If you get
927 random kernel OOPSes or reboots that don't seem to be related to
928 anything, try disabling/enabling this option (or disabling/enabling
931 Some other things you should try when experiencing seemingly random,
934 1) make sure that you have enough swap space and that it is
936 2) pass the "no-hlt" option to the kernel
937 3) switch on floating point emulation in the kernel and pass
938 the "no387" option to the kernel
939 4) pass the "floppy=nodma" option to the kernel
940 5) pass the "mem=4M" option to the kernel (thereby disabling
941 all but the first 4 MB of RAM)
942 6) make sure that the CPU is not over clocked.
943 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
944 8) disable the cache from your BIOS settings
945 9) install a fan for the video card or exchange video RAM
946 10) install a better fan for the CPU
947 11) exchange RAM chips
948 12) exchange the motherboard.
950 To compile this driver as a module, choose M here: the
951 module will be called apm.
953 config APM_IGNORE_USER_SUSPEND
954 bool "Ignore USER SUSPEND"
957 This option will ignore USER SUSPEND requests. On machines with a
958 compliant APM BIOS, you want to say N. However, on the NEC Versa M
959 series notebooks, it is necessary to say Y because of a BIOS bug.
962 bool "Enable PM at boot time"
965 Enable APM features at boot time. From page 36 of the APM BIOS
966 specification: "When disabled, the APM BIOS does not automatically
967 power manage devices, enter the Standby State, enter the Suspend
968 State, or take power saving steps in response to CPU Idle calls."
969 This driver will make CPU Idle calls when Linux is idle (unless this
970 feature is turned off -- see "Do CPU IDLE calls", below). This
971 should always save battery power, but more complicated APM features
972 will be dependent on your BIOS implementation. You may need to turn
973 this option off if your computer hangs at boot time when using APM
974 support, or if it beeps continuously instead of suspending. Turn
975 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
976 T400CDT. This is off by default since most machines do fine without
980 bool "Make CPU Idle calls when idle"
983 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
984 On some machines, this can activate improved power savings, such as
985 a slowed CPU clock rate, when the machine is idle. These idle calls
986 are made after the idle loop has run for some length of time (e.g.,
987 333 mS). On some machines, this will cause a hang at boot time or
988 whenever the CPU becomes idle. (On machines with more than one CPU,
989 this option does nothing.)
991 config APM_DISPLAY_BLANK
992 bool "Enable console blanking using APM"
995 Enable console blanking using the APM. Some laptops can use this to
996 turn off the LCD backlight when the screen blanker of the Linux
997 virtual console blanks the screen. Note that this is only used by
998 the virtual console screen blanker, and won't turn off the backlight
999 when using the X Window system. This also doesn't have anything to
1000 do with your VESA-compliant power-saving monitor. Further, this
1001 option doesn't work for all laptops -- it might not turn off your
1002 backlight at all, or it might print a lot of errors to the console,
1003 especially if you are using gpm.
1005 config APM_RTC_IS_GMT
1006 bool "RTC stores time in GMT"
1009 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1010 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1013 It is in fact recommended to store GMT in your RTC, because then you
1014 don't have to worry about daylight savings time changes. The only
1015 reason not to use GMT in your RTC is if you also run a broken OS
1016 that doesn't understand GMT.
1018 config APM_ALLOW_INTS
1019 bool "Allow interrupts during APM BIOS calls"
1022 Normally we disable external interrupts while we are making calls to
1023 the APM BIOS as a measure to lessen the effects of a badly behaving
1024 BIOS implementation. The BIOS should reenable interrupts if it
1025 needs to. Unfortunately, some BIOSes do not -- especially those in
1026 many of the newer IBM Thinkpads. If you experience hangs when you
1027 suspend, try setting this to Y. Otherwise, say N.
1029 config APM_REAL_MODE_POWER_OFF
1030 bool "Use real mode APM BIOS call to power off"
1033 Use real mode APM BIOS calls to switch off the computer. This is
1034 a work-around for a number of buggy BIOSes. Switch this option on if
1035 your computer crashes instead of powering off properly.
1039 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1043 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1046 bool "PCI support" if !X86_VISWS
1047 depends on !X86_VOYAGER
1048 default y if X86_VISWS
1050 Find out whether you have a PCI motherboard. PCI is the name of a
1051 bus system, i.e. the way the CPU talks to the other stuff inside
1052 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1053 VESA. If you have PCI, say Y, otherwise N.
1055 The PCI-HOWTO, available from
1056 <http://www.tldp.org/docs.html#howto>, contains valuable
1057 information about which PCI hardware does work under Linux and which
1061 prompt "PCI access mode"
1062 depends on PCI && !X86_VISWS
1065 On PCI systems, the BIOS can be used to detect the PCI devices and
1066 determine their configuration. However, some old PCI motherboards
1067 have BIOS bugs and may crash if this is done. Also, some embedded
1068 PCI-based systems don't have any BIOS at all. Linux can also try to
1069 detect the PCI hardware directly without using the BIOS.
1071 With this option, you can specify how Linux should detect the
1072 PCI devices. If you choose "BIOS", the BIOS will be used,
1073 if you choose "Direct", the BIOS won't be used, and if you
1074 choose "MMConfig", then PCI Express MMCONFIG will be used.
1075 If you choose "Any", the kernel will try MMCONFIG, then the
1076 direct access method and falls back to the BIOS if that doesn't
1077 work. If unsure, go with the default, which is "Any".
1082 config PCI_GOMMCONFIG
1095 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1100 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1105 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1108 source "drivers/pci/pcie/Kconfig"
1110 source "drivers/pci/Kconfig"
1118 depends on !(X86_VOYAGER || X86_VISWS)
1120 Find out whether you have ISA slots on your motherboard. ISA is the
1121 name of a bus system, i.e. the way the CPU talks to the other stuff
1122 inside your box. Other bus systems are PCI, EISA, MicroChannel
1123 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1124 newer boards don't support it. If you have ISA, say Y, otherwise N.
1130 The Extended Industry Standard Architecture (EISA) bus was
1131 developed as an open alternative to the IBM MicroChannel bus.
1133 The EISA bus provided some of the features of the IBM MicroChannel
1134 bus while maintaining backward compatibility with cards made for
1135 the older ISA bus. The EISA bus saw limited use between 1988 and
1136 1995 when it was made obsolete by the PCI bus.
1138 Say Y here if you are building a kernel for an EISA-based machine.
1142 source "drivers/eisa/Kconfig"
1145 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1146 default y if X86_VOYAGER
1148 MicroChannel Architecture is found in some IBM PS/2 machines and
1149 laptops. It is a bus system similar to PCI or ISA. See
1150 <file:Documentation/mca.txt> (and especially the web page given
1151 there) before attempting to build an MCA bus kernel.
1153 source "drivers/mca/Kconfig"
1156 tristate "NatSemi SCx200 support"
1157 depends on !X86_VOYAGER
1159 This provides basic support for National Semiconductor's
1160 (now AMD's) Geode processors. The driver probes for the
1161 PCI-IDs of several on-chip devices, so its a good dependency
1162 for other scx200_* drivers.
1164 If compiled as a module, the driver is named scx200.
1166 config SCx200HR_TIMER
1167 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1168 depends on SCx200 && GENERIC_TIME
1171 This driver provides a clocksource built upon the on-chip
1172 27MHz high-resolution timer. Its also a workaround for
1173 NSC Geode SC-1100's buggy TSC, which loses time when the
1174 processor goes idle (as is done by the scheduler). The
1175 other workaround is idle=poll boot option.
1179 depends on AGP_AMD64
1181 source "drivers/pcmcia/Kconfig"
1183 source "drivers/pci/hotplug/Kconfig"
1187 menu "Executable file formats"
1189 source "fs/Kconfig.binfmt"
1193 source "net/Kconfig"
1195 source "drivers/Kconfig"
1199 menu "Instrumentation Support"
1200 depends on EXPERIMENTAL
1202 source "arch/i386/oprofile/Kconfig"
1205 bool "Kprobes (EXPERIMENTAL)"
1206 depends on KALLSYMS && EXPERIMENTAL && MODULES
1208 Kprobes allows you to trap at almost any kernel address and
1209 execute a callback function. register_kprobe() establishes
1210 a probepoint and specifies the callback. Kprobes is useful
1211 for kernel debugging, non-intrusive instrumentation and testing.
1212 If in doubt, say "N".
1215 source "arch/i386/Kconfig.debug"
1217 source "security/Kconfig"
1219 source "crypto/Kconfig"
1221 source "lib/Kconfig"
1224 # Use the generic interrupt handling code in kernel/irq/:
1226 config GENERIC_HARDIRQS
1230 config GENERIC_IRQ_PROBE
1234 config GENERIC_PENDING_IRQ
1236 depends on GENERIC_HARDIRQS && SMP
1241 depends on SMP && !X86_VOYAGER
1246 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1249 config X86_BIOS_REBOOT
1251 depends on !(X86_VISWS || X86_VOYAGER)
1254 config X86_TRAMPOLINE
1256 depends on X86_SMP || (X86_VOYAGER && SMP)
projects / linux-2.6 / blob