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
48 config GENERIC_ISA_DMA
61 config GENERIC_HWEIGHT
65 config ARCH_MAY_HAVE_PC_FDC
75 menu "Processor type and features"
78 bool "Symmetric multi-processing support"
80 This enables support for systems with more than one CPU. If you have
81 a system with only one CPU, like most personal computers, say N. If
82 you have a system with more than one CPU, say Y.
84 If you say N here, the kernel will run on single and multiprocessor
85 machines, but will use only one CPU of a multiprocessor machine. If
86 you say Y here, the kernel will run on many, but not all,
87 singleprocessor machines. On a singleprocessor machine, the kernel
88 will run faster if you say N here.
90 Note that if you say Y here and choose architecture "586" or
91 "Pentium" under "Processor family", the kernel will not work on 486
92 architectures. Similarly, multiprocessor kernels for the "PPro"
93 architecture may not work on all Pentium based boards.
95 People using multiprocessor machines who say Y here should also say
96 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
97 Management" code will be disabled if you say Y here.
99 See also the <file:Documentation/smp.txt>,
100 <file:Documentation/i386/IO-APIC.txt>,
101 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
102 <http://www.tldp.org/docs.html#howto>.
104 If you don't know what to do here, say N.
107 prompt "Subarchitecture Type"
113 Choose this option if your computer is a standard PC or compatible.
118 Select this for an AMD Elan processor.
120 Do not use this option for K6/Athlon/Opteron processors!
122 If unsure, choose "PC-compatible" instead.
127 Voyager is an MCA-based 32-way capable SMP architecture proprietary
128 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
132 If you do not specifically know you have a Voyager based machine,
133 say N here, otherwise the kernel you build will not be bootable.
136 bool "NUMAQ (IBM/Sequent)"
140 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
141 multiquad box. This changes the way that processors are bootstrapped,
142 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
143 You will need a new lynxer.elf file to flash your firmware with - send
144 email to <Martin.Bligh@us.ibm.com>.
147 bool "Summit/EXA (IBM x440)"
150 This option is needed for IBM systems that use the Summit/EXA chipset.
151 In particular, it is needed for the x440.
153 If you don't have one of these computers, you should say N here.
154 If you want to build a NUMA kernel, you must select ACPI.
157 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
160 This option is needed for the systems that have more than 8 CPUs
161 and if the system is not of any sub-arch type above.
163 If you don't have such a system, you should say N here.
166 bool "SGI 320/540 (Visual Workstation)"
168 The SGI Visual Workstation series is an IA32-based workstation
169 based on SGI systems chips with some legacy PC hardware attached.
171 Say Y here to create a kernel to run on the SGI 320 or 540.
173 A kernel compiled for the Visual Workstation will not run on PCs
174 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
176 config X86_GENERICARCH
177 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
179 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
180 It is intended for a generic binary kernel.
181 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
184 bool "Support for Unisys ES7000 IA32 series"
187 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
188 supposed to run on an IA32-based Unisys ES7000 system.
189 Only choose this option if you have such a system, otherwise you
195 bool "Paravirtualization support (EXPERIMENTAL)"
196 depends on EXPERIMENTAL
197 depends on !(X86_VISWS || X86_VOYAGER)
199 Paravirtualization is a way of running multiple instances of
200 Linux on the same machine, under a hypervisor. This option
201 changes the kernel so it can modify itself when it is run
202 under a hypervisor, improving performance significantly.
203 However, when run without a hypervisor the kernel is
204 theoretically slower. If in doubt, say N.
209 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
212 config HAVE_ARCH_PARSE_SRAT
217 config X86_SUMMIT_NUMA
220 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
222 config X86_CYCLONE_TIMER
225 depends on X86_SUMMIT || X86_GENERICARCH
227 config ES7000_CLUSTERED_APIC
230 depends on SMP && X86_ES7000 && MPENTIUMIII
232 source "arch/i386/Kconfig.cpu"
235 bool "HPET Timer Support"
237 This enables the use of the HPET for the kernel's internal timer.
238 HPET is the next generation timer replacing legacy 8254s.
239 You can safely choose Y here. However, HPET will only be
240 activated if the platform and the BIOS support this feature.
241 Otherwise the 8254 will be used for timing services.
243 Choose N to continue using the legacy 8254 timer.
245 config HPET_EMULATE_RTC
247 depends on HPET_TIMER && RTC=y
251 int "Maximum number of CPUs (2-255)"
254 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
257 This allows you to specify the maximum number of CPUs which this
258 kernel will support. The maximum supported value is 255 and the
259 minimum value which makes sense is 2.
261 This is purely to save memory - each supported CPU adds
262 approximately eight kilobytes to the kernel image.
265 bool "SMT (Hyperthreading) scheduler support"
268 SMT scheduler support improves the CPU scheduler's decision making
269 when dealing with Intel Pentium 4 chips with HyperThreading at a
270 cost of slightly increased overhead in some places. If unsure say
274 bool "Multi-core scheduler support"
278 Multi-core scheduler support improves the CPU scheduler's decision
279 making when dealing with multi-core CPU chips at a cost of slightly
280 increased overhead in some places. If unsure say N here.
282 source "kernel/Kconfig.preempt"
285 bool "Local APIC support on uniprocessors"
286 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
288 A local APIC (Advanced Programmable Interrupt Controller) is an
289 integrated interrupt controller in the CPU. If you have a single-CPU
290 system which has a processor with a local APIC, you can say Y here to
291 enable and use it. If you say Y here even though your machine doesn't
292 have a local APIC, then the kernel will still run with no slowdown at
293 all. The local APIC supports CPU-generated self-interrupts (timer,
294 performance counters), and the NMI watchdog which detects hard
298 bool "IO-APIC support on uniprocessors"
299 depends on X86_UP_APIC
301 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
302 SMP-capable replacement for PC-style interrupt controllers. Most
303 SMP systems and many recent uniprocessor systems have one.
305 If you have a single-CPU system with an IO-APIC, you can say Y here
306 to use it. If you say Y here even though your machine doesn't have
307 an IO-APIC, then the kernel will still run with no slowdown at all.
309 config X86_LOCAL_APIC
311 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
316 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
319 config X86_VISWS_APIC
325 bool "Machine Check Exception"
326 depends on !X86_VOYAGER
328 Machine Check Exception support allows the processor to notify the
329 kernel if it detects a problem (e.g. overheating, component failure).
330 The action the kernel takes depends on the severity of the problem,
331 ranging from a warning message on the console, to halting the machine.
332 Your processor must be a Pentium or newer to support this - check the
333 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
334 have a design flaw which leads to false MCE events - hence MCE is
335 disabled on all P5 processors, unless explicitly enabled with "mce"
336 as a boot argument. Similarly, if MCE is built in and creates a
337 problem on some new non-standard machine, you can boot with "nomce"
338 to disable it. MCE support simply ignores non-MCE processors like
339 the 386 and 486, so nearly everyone can say Y here.
341 config X86_MCE_NONFATAL
342 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
345 Enabling this feature starts a timer that triggers every 5 seconds which
346 will look at the machine check registers to see if anything happened.
347 Non-fatal problems automatically get corrected (but still logged).
348 Disable this if you don't want to see these messages.
349 Seeing the messages this option prints out may be indicative of dying hardware,
350 or out-of-spec (ie, overclocked) hardware.
351 This option only does something on certain CPUs.
352 (AMD Athlon/Duron and Intel Pentium 4)
354 config X86_MCE_P4THERMAL
355 bool "check for P4 thermal throttling interrupt."
356 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
358 Enabling this feature will cause a message to be printed when the P4
359 enters thermal throttling.
363 bool "Enable VM86 support" if EMBEDDED
365 This option is required by programs like DOSEMU to run 16-bit legacy
366 code on X86 processors. It also may be needed by software like
367 XFree86 to initialize some video cards via BIOS. Disabling this
368 option saves about 6k.
371 tristate "Toshiba Laptop support"
373 This adds a driver to safely access the System Management Mode of
374 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
375 not work on models with a Phoenix BIOS. The System Management Mode
376 is used to set the BIOS and power saving options on Toshiba portables.
378 For information on utilities to make use of this driver see the
379 Toshiba Linux utilities web site at:
380 <http://www.buzzard.org.uk/toshiba/>.
382 Say Y if you intend to run this kernel on a Toshiba portable.
386 tristate "Dell laptop support"
388 This adds a driver to safely access the System Management Mode
389 of the CPU on the Dell Inspiron 8000. The System Management Mode
390 is used to read cpu temperature and cooling fan status and to
391 control the fans on the I8K portables.
393 This driver has been tested only on the Inspiron 8000 but it may
394 also work with other Dell laptops. You can force loading on other
395 models by passing the parameter `force=1' to the module. Use at
398 For information on utilities to make use of this driver see the
399 I8K Linux utilities web site at:
400 <http://people.debian.org/~dz/i8k/>
402 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
405 config X86_REBOOTFIXUPS
406 bool "Enable X86 board specific fixups for reboot"
410 This enables chipset and/or board specific fixups to be done
411 in order to get reboot to work correctly. This is only needed on
412 some combinations of hardware and BIOS. The symptom, for which
413 this config is intended, is when reboot ends with a stalled/hung
416 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
419 Say Y if you want to enable the fixup. Currently, it's safe to
420 enable this option even if you don't need it.
424 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
427 If you say Y here and also to "/dev file system support" in the
428 'File systems' section, you will be able to update the microcode on
429 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
430 Pentium III, Pentium 4, Xeon etc. You will obviously need the
431 actual microcode binary data itself which is not shipped with the
434 For latest news and information on obtaining all the required
435 ingredients for this driver, check:
436 <http://www.urbanmyth.org/microcode/>.
438 To compile this driver as a module, choose M here: the
439 module will be called microcode.
441 config MICROCODE_OLD_INTERFACE
447 tristate "/dev/cpu/*/msr - Model-specific register support"
449 This device gives privileged processes access to the x86
450 Model-Specific Registers (MSRs). It is a character device with
451 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
452 MSR accesses are directed to a specific CPU on multi-processor
456 tristate "/dev/cpu/*/cpuid - CPU information support"
458 This device gives processes access to the x86 CPUID instruction to
459 be executed on a specific processor. It is a character device
460 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
463 source "drivers/firmware/Kconfig"
466 prompt "High Memory Support"
467 default HIGHMEM4G if !X86_NUMAQ
468 default HIGHMEM64G if X86_NUMAQ
472 depends on !X86_NUMAQ
474 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
475 However, the address space of 32-bit x86 processors is only 4
476 Gigabytes large. That means that, if you have a large amount of
477 physical memory, not all of it can be "permanently mapped" by the
478 kernel. The physical memory that's not permanently mapped is called
481 If you are compiling a kernel which will never run on a machine with
482 more than 1 Gigabyte total physical RAM, answer "off" here (default
483 choice and suitable for most users). This will result in a "3GB/1GB"
484 split: 3GB are mapped so that each process sees a 3GB virtual memory
485 space and the remaining part of the 4GB virtual memory space is used
486 by the kernel to permanently map as much physical memory as
489 If the machine has between 1 and 4 Gigabytes physical RAM, then
492 If more than 4 Gigabytes is used then answer "64GB" here. This
493 selection turns Intel PAE (Physical Address Extension) mode on.
494 PAE implements 3-level paging on IA32 processors. PAE is fully
495 supported by Linux, PAE mode is implemented on all recent Intel
496 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
497 then the kernel will not boot on CPUs that don't support PAE!
499 The actual amount of total physical memory will either be
500 auto detected or can be forced by using a kernel command line option
501 such as "mem=256M". (Try "man bootparam" or see the documentation of
502 your boot loader (lilo or loadlin) about how to pass options to the
503 kernel at boot time.)
505 If unsure, say "off".
509 depends on !X86_NUMAQ
511 Select this if you have a 32-bit processor and between 1 and 4
512 gigabytes of physical RAM.
516 depends on X86_CMPXCHG64
518 Select this if you have a 32-bit processor and more than 4
519 gigabytes of physical RAM.
524 depends on EXPERIMENTAL
525 prompt "Memory split" if EMBEDDED
528 Select the desired split between kernel and user memory.
530 If the address range available to the kernel is less than the
531 physical memory installed, the remaining memory will be available
532 as "high memory". Accessing high memory is a little more costly
533 than low memory, as it needs to be mapped into the kernel first.
534 Note that increasing the kernel address space limits the range
535 available to user programs, making the address space there
536 tighter. Selecting anything other than the default 3G/1G split
537 will also likely make your kernel incompatible with binary-only
540 If you are not absolutely sure what you are doing, leave this
544 bool "3G/1G user/kernel split"
545 config VMSPLIT_3G_OPT
547 bool "3G/1G user/kernel split (for full 1G low memory)"
549 bool "2G/2G user/kernel split"
551 bool "1G/3G user/kernel split"
556 default 0xB0000000 if VMSPLIT_3G_OPT
557 default 0x78000000 if VMSPLIT_2G
558 default 0x40000000 if VMSPLIT_1G
563 depends on HIGHMEM64G || HIGHMEM4G
568 depends on HIGHMEM64G
570 select RESOURCES_64BIT
572 # Common NUMA Features
574 bool "Numa Memory Allocation and Scheduler Support"
575 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
577 default y if (X86_NUMAQ || X86_SUMMIT)
579 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
580 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
584 default "4" if X86_NUMAQ
586 depends on NEED_MULTIPLE_NODES
588 config HAVE_ARCH_BOOTMEM_NODE
593 config ARCH_HAVE_MEMORY_PRESENT
595 depends on DISCONTIGMEM
598 config NEED_NODE_MEMMAP_SIZE
600 depends on DISCONTIGMEM || SPARSEMEM
603 config HAVE_ARCH_ALLOC_REMAP
608 config ARCH_FLATMEM_ENABLE
610 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
612 config ARCH_DISCONTIGMEM_ENABLE
616 config ARCH_DISCONTIGMEM_DEFAULT
620 config ARCH_SPARSEMEM_ENABLE
622 depends on (NUMA || (X86_PC && EXPERIMENTAL))
623 select SPARSEMEM_STATIC
625 config ARCH_SELECT_MEMORY_MODEL
627 depends on ARCH_SPARSEMEM_ENABLE
629 config ARCH_POPULATES_NODE_MAP
635 bool "Allocate 3rd-level pagetables from highmem"
636 depends on HIGHMEM4G || HIGHMEM64G
638 The VM uses one page table entry for each page of physical memory.
639 For systems with a lot of RAM, this can be wasteful of precious
640 low memory. Setting this option will put user-space page table
641 entries in high memory.
643 config MATH_EMULATION
644 bool "Math emulation"
646 Linux can emulate a math coprocessor (used for floating point
647 operations) if you don't have one. 486DX and Pentium processors have
648 a math coprocessor built in, 486SX and 386 do not, unless you added
649 a 487DX or 387, respectively. (The messages during boot time can
650 give you some hints here ["man dmesg"].) Everyone needs either a
651 coprocessor or this emulation.
653 If you don't have a math coprocessor, you need to say Y here; if you
654 say Y here even though you have a coprocessor, the coprocessor will
655 be used nevertheless. (This behavior can be changed with the kernel
656 command line option "no387", which comes handy if your coprocessor
657 is broken. Try "man bootparam" or see the documentation of your boot
658 loader (lilo or loadlin) about how to pass options to the kernel at
659 boot time.) This means that it is a good idea to say Y here if you
660 intend to use this kernel on different machines.
662 More information about the internals of the Linux math coprocessor
663 emulation can be found in <file:arch/i386/math-emu/README>.
665 If you are not sure, say Y; apart from resulting in a 66 KB bigger
666 kernel, it won't hurt.
669 bool "MTRR (Memory Type Range Register) support"
671 On Intel P6 family processors (Pentium Pro, Pentium II and later)
672 the Memory Type Range Registers (MTRRs) may be used to control
673 processor access to memory ranges. This is most useful if you have
674 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
675 allows bus write transfers to be combined into a larger transfer
676 before bursting over the PCI/AGP bus. This can increase performance
677 of image write operations 2.5 times or more. Saying Y here creates a
678 /proc/mtrr file which may be used to manipulate your processor's
679 MTRRs. Typically the X server should use this.
681 This code has a reasonably generic interface so that similar
682 control registers on other processors can be easily supported
685 The Cyrix 6x86, 6x86MX and M II processors have Address Range
686 Registers (ARRs) which provide a similar functionality to MTRRs. For
687 these, the ARRs are used to emulate the MTRRs.
688 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
689 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
690 write-combining. All of these processors are supported by this code
691 and it makes sense to say Y here if you have one of them.
693 Saying Y here also fixes a problem with buggy SMP BIOSes which only
694 set the MTRRs for the boot CPU and not for the secondary CPUs. This
695 can lead to all sorts of problems, so it's good to say Y here.
697 You can safely say Y even if your machine doesn't have MTRRs, you'll
698 just add about 9 KB to your kernel.
700 See <file:Documentation/mtrr.txt> for more information.
703 bool "Boot from EFI support"
707 This enables the kernel to boot on EFI platforms using
708 system configuration information passed to it from the firmware.
709 This also enables the kernel to use any EFI runtime services that are
710 available (such as the EFI variable services).
712 This option is only useful on systems that have EFI firmware
713 and will result in a kernel image that is ~8k larger. In addition,
714 you must use the latest ELILO loader available at
715 <http://elilo.sourceforge.net> in order to take advantage of
716 kernel initialization using EFI information (neither GRUB nor LILO know
717 anything about EFI). However, even with this option, the resultant
718 kernel should continue to boot on existing non-EFI platforms.
721 bool "Enable kernel irq balancing"
722 depends on SMP && X86_IO_APIC
725 The default yes will allow the kernel to do irq load balancing.
726 Saying no will keep the kernel from doing irq load balancing.
728 # turning this on wastes a bunch of space.
729 # Summit needs it only when NUMA is on
732 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
736 bool "Enable seccomp to safely compute untrusted bytecode"
740 This kernel feature is useful for number crunching applications
741 that may need to compute untrusted bytecode during their
742 execution. By using pipes or other transports made available to
743 the process as file descriptors supporting the read/write
744 syscalls, it's possible to isolate those applications in
745 their own address space using seccomp. Once seccomp is
746 enabled via /proc/<pid>/seccomp, it cannot be disabled
747 and the task is only allowed to execute a few safe syscalls
748 defined by each seccomp mode.
750 If unsure, say Y. Only embedded should say N here.
752 source kernel/Kconfig.hz
755 bool "kexec system call"
757 kexec is a system call that implements the ability to shutdown your
758 current kernel, and to start another kernel. It is like a reboot
759 but it is independent of the system firmware. And like a reboot
760 you can start any kernel with it, not just Linux.
762 The name comes from the similarity to the exec system call.
764 It is an ongoing process to be certain the hardware in a machine
765 is properly shutdown, so do not be surprised if this code does not
766 initially work for you. It may help to enable device hotplugging
767 support. As of this writing the exact hardware interface is
768 strongly in flux, so no good recommendation can be made.
771 bool "kernel crash dumps (EXPERIMENTAL)"
772 depends on EXPERIMENTAL
775 Generate crash dump after being started by kexec.
776 This should be normally only set in special crash dump kernels
777 which are loaded in the main kernel with kexec-tools into
778 a specially reserved region and then later executed after
779 a crash by kdump/kexec. The crash dump kernel must be compiled
780 to a memory address not used by the main kernel or BIOS using
782 For more details see Documentation/kdump/kdump.txt
784 config PHYSICAL_START
785 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
788 This gives the physical address where the kernel is loaded.
790 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
791 bzImage will decompress itself to above physical address and
792 run from there. Otherwise, bzImage will run from the address where
793 it has been loaded by the boot loader and will ignore above physical
796 In normal kdump cases one does not have to set/change this option
797 as now bzImage can be compiled as a completely relocatable image
798 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
799 address. This option is mainly useful for the folks who don't want
800 to use a bzImage for capturing the crash dump and want to use a
801 vmlinux instead. vmlinux is not relocatable hence a kernel needs
802 to be specifically compiled to run from a specific memory area
803 (normally a reserved region) and this option comes handy.
805 So if you are using bzImage for capturing the crash dump, leave
806 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
807 Otherwise if you plan to use vmlinux for capturing the crash dump
808 change this value to start of the reserved region (Typically 16MB
809 0x1000000). In other words, it can be set based on the "X" value as
810 specified in the "crashkernel=YM@XM" command line boot parameter
811 passed to the panic-ed kernel. Typically this parameter is set as
812 crashkernel=64M@16M. Please take a look at
813 Documentation/kdump/kdump.txt for more details about crash dumps.
815 Usage of bzImage for capturing the crash dump is recommended as
816 one does not have to build two kernels. Same kernel can be used
817 as production kernel and capture kernel. Above option should have
818 gone away after relocatable bzImage support is introduced. But it
819 is present because there are users out there who continue to use
820 vmlinux for dump capture. This option should go away down the
823 Don't change this unless you know what you are doing.
826 bool "Build a relocatable kernel(EXPERIMENTAL)"
827 depends on EXPERIMENTAL
829 This build a kernel image that retains relocation information
830 so it can be loaded someplace besides the default 1MB.
831 The relocations tend to the kernel binary about 10% larger,
832 but are discarded at runtime.
834 One use is for the kexec on panic case where the recovery kernel
835 must live at a different physical address than the primary
838 config PHYSICAL_ALIGN
839 hex "Alignment value to which kernel should be aligned"
841 range 0x2000 0x400000
843 This value puts the alignment restrictions on physical address
844 where kernel is loaded and run from. Kernel is compiled for an
845 address which meets above alignment restriction.
847 If bootloader loads the kernel at a non-aligned address and
848 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
849 address aligned to above value and run from there.
851 If bootloader loads the kernel at a non-aligned address and
852 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
853 load address and decompress itself to the address it has been
854 compiled for and run from there. The address for which kernel is
855 compiled already meets above alignment restrictions. Hence the
856 end result is that kernel runs from a physical address meeting
857 above alignment restrictions.
859 Don't change this unless you know what you are doing.
862 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
863 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
865 Say Y here to experiment with turning CPUs off and on, and to
866 enable suspend on SMP systems. CPUs can be controlled through
867 /sys/devices/system/cpu.
870 bool "Compat VDSO support"
874 Map the VDSO to the predictable old-style address too.
876 Say N here if you are running a sufficiently recent glibc
877 version (2.3.3 or later), to remove the high-mapped
878 VDSO mapping and to exclusively use the randomized VDSO.
884 config ARCH_ENABLE_MEMORY_HOTPLUG
888 menu "Power management options (ACPI, APM)"
889 depends on !X86_VOYAGER
891 source kernel/power/Kconfig
893 source "drivers/acpi/Kconfig"
895 menu "APM (Advanced Power Management) BIOS Support"
896 depends on PM && !X86_VISWS
899 tristate "APM (Advanced Power Management) BIOS support"
902 APM is a BIOS specification for saving power using several different
903 techniques. This is mostly useful for battery powered laptops with
904 APM compliant BIOSes. If you say Y here, the system time will be
905 reset after a RESUME operation, the /proc/apm device will provide
906 battery status information, and user-space programs will receive
907 notification of APM "events" (e.g. battery status change).
909 If you select "Y" here, you can disable actual use of the APM
910 BIOS by passing the "apm=off" option to the kernel at boot time.
912 Note that the APM support is almost completely disabled for
913 machines with more than one CPU.
915 In order to use APM, you will need supporting software. For location
916 and more information, read <file:Documentation/pm.txt> and the
917 Battery Powered Linux mini-HOWTO, available from
918 <http://www.tldp.org/docs.html#howto>.
920 This driver does not spin down disk drives (see the hdparm(8)
921 manpage ("man 8 hdparm") for that), and it doesn't turn off
922 VESA-compliant "green" monitors.
924 This driver does not support the TI 4000M TravelMate and the ACER
925 486/DX4/75 because they don't have compliant BIOSes. Many "green"
926 desktop machines also don't have compliant BIOSes, and this driver
927 may cause those machines to panic during the boot phase.
929 Generally, if you don't have a battery in your machine, there isn't
930 much point in using this driver and you should say N. If you get
931 random kernel OOPSes or reboots that don't seem to be related to
932 anything, try disabling/enabling this option (or disabling/enabling
935 Some other things you should try when experiencing seemingly random,
938 1) make sure that you have enough swap space and that it is
940 2) pass the "no-hlt" option to the kernel
941 3) switch on floating point emulation in the kernel and pass
942 the "no387" option to the kernel
943 4) pass the "floppy=nodma" option to the kernel
944 5) pass the "mem=4M" option to the kernel (thereby disabling
945 all but the first 4 MB of RAM)
946 6) make sure that the CPU is not over clocked.
947 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
948 8) disable the cache from your BIOS settings
949 9) install a fan for the video card or exchange video RAM
950 10) install a better fan for the CPU
951 11) exchange RAM chips
952 12) exchange the motherboard.
954 To compile this driver as a module, choose M here: the
955 module will be called apm.
957 config APM_IGNORE_USER_SUSPEND
958 bool "Ignore USER SUSPEND"
961 This option will ignore USER SUSPEND requests. On machines with a
962 compliant APM BIOS, you want to say N. However, on the NEC Versa M
963 series notebooks, it is necessary to say Y because of a BIOS bug.
966 bool "Enable PM at boot time"
969 Enable APM features at boot time. From page 36 of the APM BIOS
970 specification: "When disabled, the APM BIOS does not automatically
971 power manage devices, enter the Standby State, enter the Suspend
972 State, or take power saving steps in response to CPU Idle calls."
973 This driver will make CPU Idle calls when Linux is idle (unless this
974 feature is turned off -- see "Do CPU IDLE calls", below). This
975 should always save battery power, but more complicated APM features
976 will be dependent on your BIOS implementation. You may need to turn
977 this option off if your computer hangs at boot time when using APM
978 support, or if it beeps continuously instead of suspending. Turn
979 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
980 T400CDT. This is off by default since most machines do fine without
984 bool "Make CPU Idle calls when idle"
987 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
988 On some machines, this can activate improved power savings, such as
989 a slowed CPU clock rate, when the machine is idle. These idle calls
990 are made after the idle loop has run for some length of time (e.g.,
991 333 mS). On some machines, this will cause a hang at boot time or
992 whenever the CPU becomes idle. (On machines with more than one CPU,
993 this option does nothing.)
995 config APM_DISPLAY_BLANK
996 bool "Enable console blanking using APM"
999 Enable console blanking using the APM. Some laptops can use this to
1000 turn off the LCD backlight when the screen blanker of the Linux
1001 virtual console blanks the screen. Note that this is only used by
1002 the virtual console screen blanker, and won't turn off the backlight
1003 when using the X Window system. This also doesn't have anything to
1004 do with your VESA-compliant power-saving monitor. Further, this
1005 option doesn't work for all laptops -- it might not turn off your
1006 backlight at all, or it might print a lot of errors to the console,
1007 especially if you are using gpm.
1009 config APM_RTC_IS_GMT
1010 bool "RTC stores time in GMT"
1013 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1014 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1017 It is in fact recommended to store GMT in your RTC, because then you
1018 don't have to worry about daylight savings time changes. The only
1019 reason not to use GMT in your RTC is if you also run a broken OS
1020 that doesn't understand GMT.
1022 config APM_ALLOW_INTS
1023 bool "Allow interrupts during APM BIOS calls"
1026 Normally we disable external interrupts while we are making calls to
1027 the APM BIOS as a measure to lessen the effects of a badly behaving
1028 BIOS implementation. The BIOS should reenable interrupts if it
1029 needs to. Unfortunately, some BIOSes do not -- especially those in
1030 many of the newer IBM Thinkpads. If you experience hangs when you
1031 suspend, try setting this to Y. Otherwise, say N.
1033 config APM_REAL_MODE_POWER_OFF
1034 bool "Use real mode APM BIOS call to power off"
1037 Use real mode APM BIOS calls to switch off the computer. This is
1038 a work-around for a number of buggy BIOSes. Switch this option on if
1039 your computer crashes instead of powering off properly.
1043 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1047 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1050 bool "PCI support" if !X86_VISWS
1051 depends on !X86_VOYAGER
1052 default y if X86_VISWS
1054 Find out whether you have a PCI motherboard. PCI is the name of a
1055 bus system, i.e. the way the CPU talks to the other stuff inside
1056 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1057 VESA. If you have PCI, say Y, otherwise N.
1059 The PCI-HOWTO, available from
1060 <http://www.tldp.org/docs.html#howto>, contains valuable
1061 information about which PCI hardware does work under Linux and which
1065 prompt "PCI access mode"
1066 depends on PCI && !X86_VISWS
1069 On PCI systems, the BIOS can be used to detect the PCI devices and
1070 determine their configuration. However, some old PCI motherboards
1071 have BIOS bugs and may crash if this is done. Also, some embedded
1072 PCI-based systems don't have any BIOS at all. Linux can also try to
1073 detect the PCI hardware directly without using the BIOS.
1075 With this option, you can specify how Linux should detect the
1076 PCI devices. If you choose "BIOS", the BIOS will be used,
1077 if you choose "Direct", the BIOS won't be used, and if you
1078 choose "MMConfig", then PCI Express MMCONFIG will be used.
1079 If you choose "Any", the kernel will try MMCONFIG, then the
1080 direct access method and falls back to the BIOS if that doesn't
1081 work. If unsure, go with the default, which is "Any".
1086 config PCI_GOMMCONFIG
1099 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1104 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1109 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1112 source "drivers/pci/pcie/Kconfig"
1114 source "drivers/pci/Kconfig"
1122 depends on !(X86_VOYAGER || X86_VISWS)
1124 Find out whether you have ISA slots on your motherboard. ISA is the
1125 name of a bus system, i.e. the way the CPU talks to the other stuff
1126 inside your box. Other bus systems are PCI, EISA, MicroChannel
1127 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1128 newer boards don't support it. If you have ISA, say Y, otherwise N.
1134 The Extended Industry Standard Architecture (EISA) bus was
1135 developed as an open alternative to the IBM MicroChannel bus.
1137 The EISA bus provided some of the features of the IBM MicroChannel
1138 bus while maintaining backward compatibility with cards made for
1139 the older ISA bus. The EISA bus saw limited use between 1988 and
1140 1995 when it was made obsolete by the PCI bus.
1142 Say Y here if you are building a kernel for an EISA-based machine.
1146 source "drivers/eisa/Kconfig"
1149 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1150 default y if X86_VOYAGER
1152 MicroChannel Architecture is found in some IBM PS/2 machines and
1153 laptops. It is a bus system similar to PCI or ISA. See
1154 <file:Documentation/mca.txt> (and especially the web page given
1155 there) before attempting to build an MCA bus kernel.
1157 source "drivers/mca/Kconfig"
1160 tristate "NatSemi SCx200 support"
1161 depends on !X86_VOYAGER
1163 This provides basic support for National Semiconductor's
1164 (now AMD's) Geode processors. The driver probes for the
1165 PCI-IDs of several on-chip devices, so its a good dependency
1166 for other scx200_* drivers.
1168 If compiled as a module, the driver is named scx200.
1170 config SCx200HR_TIMER
1171 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1172 depends on SCx200 && GENERIC_TIME
1175 This driver provides a clocksource built upon the on-chip
1176 27MHz high-resolution timer. Its also a workaround for
1177 NSC Geode SC-1100's buggy TSC, which loses time when the
1178 processor goes idle (as is done by the scheduler). The
1179 other workaround is idle=poll boot option.
1183 depends on AGP_AMD64
1185 source "drivers/pcmcia/Kconfig"
1187 source "drivers/pci/hotplug/Kconfig"
1191 menu "Executable file formats"
1193 source "fs/Kconfig.binfmt"
1197 source "net/Kconfig"
1199 source "drivers/Kconfig"
1203 menu "Instrumentation Support"
1204 depends on EXPERIMENTAL
1206 source "arch/i386/oprofile/Kconfig"
1209 bool "Kprobes (EXPERIMENTAL)"
1210 depends on KALLSYMS && EXPERIMENTAL && MODULES
1212 Kprobes allows you to trap at almost any kernel address and
1213 execute a callback function. register_kprobe() establishes
1214 a probepoint and specifies the callback. Kprobes is useful
1215 for kernel debugging, non-intrusive instrumentation and testing.
1216 If in doubt, say "N".
1219 source "arch/i386/Kconfig.debug"
1221 source "security/Kconfig"
1223 source "crypto/Kconfig"
1225 source "lib/Kconfig"
1228 # Use the generic interrupt handling code in kernel/irq/:
1230 config GENERIC_HARDIRQS
1234 config GENERIC_IRQ_PROBE
1238 config GENERIC_PENDING_IRQ
1240 depends on GENERIC_HARDIRQS && SMP
1245 depends on SMP && !X86_VOYAGER
1250 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1253 config X86_BIOS_REBOOT
1255 depends on !(X86_VISWS || X86_VOYAGER)
1258 config X86_TRAMPOLINE
1260 depends on X86_SMP || (X86_VOYAGER && SMP)
projects / linux-2.6 / blob