2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
6 mainmenu "Linux Kernel Configuration"
12 This is Linux's home port. Linux was originally native to the Intel
13 386, and runs on all the later x86 processors including the Intel
14 486, 586, Pentiums, and various instruction-set-compatible chips by
15 AMD, Cyrix, and others.
21 config CLOCKSOURCE_WATCHDOG
25 config GENERIC_CLOCKEVENTS
29 config GENERIC_CLOCKEVENTS_BROADCAST
32 depends on X86_LOCAL_APIC
34 config LOCKDEP_SUPPORT
38 config STACKTRACE_SUPPORT
42 config SEMAPHORE_SLEEPERS
65 config GENERIC_ISA_DMA
78 config GENERIC_HWEIGHT
82 config ARCH_MAY_HAVE_PC_FDC
92 menu "Processor type and features"
94 source "kernel/time/Kconfig"
97 bool "Symmetric multi-processing support"
99 This enables support for systems with more than one CPU. If you have
100 a system with only one CPU, like most personal computers, say N. If
101 you have a system with more than one CPU, say Y.
103 If you say N here, the kernel will run on single and multiprocessor
104 machines, but will use only one CPU of a multiprocessor machine. If
105 you say Y here, the kernel will run on many, but not all,
106 singleprocessor machines. On a singleprocessor machine, the kernel
107 will run faster if you say N here.
109 Note that if you say Y here and choose architecture "586" or
110 "Pentium" under "Processor family", the kernel will not work on 486
111 architectures. Similarly, multiprocessor kernels for the "PPro"
112 architecture may not work on all Pentium based boards.
114 People using multiprocessor machines who say Y here should also say
115 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
116 Management" code will be disabled if you say Y here.
118 See also the <file:Documentation/smp.txt>,
119 <file:Documentation/i386/IO-APIC.txt>,
120 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
121 <http://www.tldp.org/docs.html#howto>.
123 If you don't know what to do here, say N.
126 prompt "Subarchitecture Type"
132 Choose this option if your computer is a standard PC or compatible.
137 Select this for an AMD Elan processor.
139 Do not use this option for K6/Athlon/Opteron processors!
141 If unsure, choose "PC-compatible" instead.
146 Voyager is an MCA-based 32-way capable SMP architecture proprietary
147 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
151 If you do not specifically know you have a Voyager based machine,
152 say N here, otherwise the kernel you build will not be bootable.
155 bool "NUMAQ (IBM/Sequent)"
159 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
160 multiquad box. This changes the way that processors are bootstrapped,
161 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
162 You will need a new lynxer.elf file to flash your firmware with - send
163 email to <Martin.Bligh@us.ibm.com>.
166 bool "Summit/EXA (IBM x440)"
169 This option is needed for IBM systems that use the Summit/EXA chipset.
170 In particular, it is needed for the x440.
172 If you don't have one of these computers, you should say N here.
173 If you want to build a NUMA kernel, you must select ACPI.
176 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
179 This option is needed for the systems that have more than 8 CPUs
180 and if the system is not of any sub-arch type above.
182 If you don't have such a system, you should say N here.
185 bool "SGI 320/540 (Visual Workstation)"
187 The SGI Visual Workstation series is an IA32-based workstation
188 based on SGI systems chips with some legacy PC hardware attached.
190 Say Y here to create a kernel to run on the SGI 320 or 540.
192 A kernel compiled for the Visual Workstation will not run on PCs
193 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
195 config X86_GENERICARCH
196 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
198 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
199 It is intended for a generic binary kernel.
200 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
203 bool "Support for Unisys ES7000 IA32 series"
206 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
207 supposed to run on an IA32-based Unisys ES7000 system.
208 Only choose this option if you have such a system, otherwise you
214 bool "Paravirtualization support (EXPERIMENTAL)"
215 depends on EXPERIMENTAL
216 depends on !(X86_VISWS || X86_VOYAGER)
218 Paravirtualization is a way of running multiple instances of
219 Linux on the same machine, under a hypervisor. This option
220 changes the kernel so it can modify itself when it is run
221 under a hypervisor, improving performance significantly.
222 However, when run without a hypervisor the kernel is
223 theoretically slower. If in doubt, say N.
226 bool "VMI Paravirt-ops support"
229 VMI provides a paravirtualized interface to the VMware ESX server
230 (it could be used by other hypervisors in theory too, but is not
231 at the moment), by linking the kernel to a GPL-ed ROM module
232 provided by the hypervisor.
237 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
240 config HAVE_ARCH_PARSE_SRAT
245 config X86_SUMMIT_NUMA
248 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
250 config X86_CYCLONE_TIMER
253 depends on X86_SUMMIT || X86_GENERICARCH
255 config ES7000_CLUSTERED_APIC
258 depends on SMP && X86_ES7000 && MPENTIUMIII
260 source "arch/i386/Kconfig.cpu"
263 bool "HPET Timer Support"
265 This enables the use of the HPET for the kernel's internal timer.
266 HPET is the next generation timer replacing legacy 8254s.
267 You can safely choose Y here. However, HPET will only be
268 activated if the platform and the BIOS support this feature.
269 Otherwise the 8254 will be used for timing services.
271 Choose N to continue using the legacy 8254 timer.
273 config HPET_EMULATE_RTC
275 depends on HPET_TIMER && RTC=y
279 int "Maximum number of CPUs (2-255)"
282 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
285 This allows you to specify the maximum number of CPUs which this
286 kernel will support. The maximum supported value is 255 and the
287 minimum value which makes sense is 2.
289 This is purely to save memory - each supported CPU adds
290 approximately eight kilobytes to the kernel image.
293 bool "SMT (Hyperthreading) scheduler support"
296 SMT scheduler support improves the CPU scheduler's decision making
297 when dealing with Intel Pentium 4 chips with HyperThreading at a
298 cost of slightly increased overhead in some places. If unsure say
302 bool "Multi-core scheduler support"
306 Multi-core scheduler support improves the CPU scheduler's decision
307 making when dealing with multi-core CPU chips at a cost of slightly
308 increased overhead in some places. If unsure say N here.
310 source "kernel/Kconfig.preempt"
313 bool "Local APIC support on uniprocessors"
314 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
316 A local APIC (Advanced Programmable Interrupt Controller) is an
317 integrated interrupt controller in the CPU. If you have a single-CPU
318 system which has a processor with a local APIC, you can say Y here to
319 enable and use it. If you say Y here even though your machine doesn't
320 have a local APIC, then the kernel will still run with no slowdown at
321 all. The local APIC supports CPU-generated self-interrupts (timer,
322 performance counters), and the NMI watchdog which detects hard
326 bool "IO-APIC support on uniprocessors"
327 depends on X86_UP_APIC
329 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
330 SMP-capable replacement for PC-style interrupt controllers. Most
331 SMP systems and many recent uniprocessor systems have one.
333 If you have a single-CPU system with an IO-APIC, you can say Y here
334 to use it. If you say Y here even though your machine doesn't have
335 an IO-APIC, then the kernel will still run with no slowdown at all.
337 config X86_LOCAL_APIC
339 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
344 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
347 config X86_VISWS_APIC
353 bool "Machine Check Exception"
354 depends on !X86_VOYAGER
356 Machine Check Exception support allows the processor to notify the
357 kernel if it detects a problem (e.g. overheating, component failure).
358 The action the kernel takes depends on the severity of the problem,
359 ranging from a warning message on the console, to halting the machine.
360 Your processor must be a Pentium or newer to support this - check the
361 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
362 have a design flaw which leads to false MCE events - hence MCE is
363 disabled on all P5 processors, unless explicitly enabled with "mce"
364 as a boot argument. Similarly, if MCE is built in and creates a
365 problem on some new non-standard machine, you can boot with "nomce"
366 to disable it. MCE support simply ignores non-MCE processors like
367 the 386 and 486, so nearly everyone can say Y here.
369 config X86_MCE_NONFATAL
370 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
373 Enabling this feature starts a timer that triggers every 5 seconds which
374 will look at the machine check registers to see if anything happened.
375 Non-fatal problems automatically get corrected (but still logged).
376 Disable this if you don't want to see these messages.
377 Seeing the messages this option prints out may be indicative of dying hardware,
378 or out-of-spec (ie, overclocked) hardware.
379 This option only does something on certain CPUs.
380 (AMD Athlon/Duron and Intel Pentium 4)
382 config X86_MCE_P4THERMAL
383 bool "check for P4 thermal throttling interrupt."
384 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
386 Enabling this feature will cause a message to be printed when the P4
387 enters thermal throttling.
391 bool "Enable VM86 support" if EMBEDDED
393 This option is required by programs like DOSEMU to run 16-bit legacy
394 code on X86 processors. It also may be needed by software like
395 XFree86 to initialize some video cards via BIOS. Disabling this
396 option saves about 6k.
399 tristate "Toshiba Laptop support"
401 This adds a driver to safely access the System Management Mode of
402 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
403 not work on models with a Phoenix BIOS. The System Management Mode
404 is used to set the BIOS and power saving options on Toshiba portables.
406 For information on utilities to make use of this driver see the
407 Toshiba Linux utilities web site at:
408 <http://www.buzzard.org.uk/toshiba/>.
410 Say Y if you intend to run this kernel on a Toshiba portable.
414 tristate "Dell laptop support"
416 This adds a driver to safely access the System Management Mode
417 of the CPU on the Dell Inspiron 8000. The System Management Mode
418 is used to read cpu temperature and cooling fan status and to
419 control the fans on the I8K portables.
421 This driver has been tested only on the Inspiron 8000 but it may
422 also work with other Dell laptops. You can force loading on other
423 models by passing the parameter `force=1' to the module. Use at
426 For information on utilities to make use of this driver see the
427 I8K Linux utilities web site at:
428 <http://people.debian.org/~dz/i8k/>
430 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
433 config X86_REBOOTFIXUPS
434 bool "Enable X86 board specific fixups for reboot"
438 This enables chipset and/or board specific fixups to be done
439 in order to get reboot to work correctly. This is only needed on
440 some combinations of hardware and BIOS. The symptom, for which
441 this config is intended, is when reboot ends with a stalled/hung
444 Currently, the only fixup is for the Geode machines using
445 CS5530A and CS5536 chipsets.
447 Say Y if you want to enable the fixup. Currently, it's safe to
448 enable this option even if you don't need it.
452 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
455 If you say Y here and also to "/dev file system support" in the
456 'File systems' section, you will be able to update the microcode on
457 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
458 Pentium III, Pentium 4, Xeon etc. You will obviously need the
459 actual microcode binary data itself which is not shipped with the
462 For latest news and information on obtaining all the required
463 ingredients for this driver, check:
464 <http://www.urbanmyth.org/microcode/>.
466 To compile this driver as a module, choose M here: the
467 module will be called microcode.
469 config MICROCODE_OLD_INTERFACE
475 tristate "/dev/cpu/*/msr - Model-specific register support"
477 This device gives privileged processes access to the x86
478 Model-Specific Registers (MSRs). It is a character device with
479 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
480 MSR accesses are directed to a specific CPU on multi-processor
484 tristate "/dev/cpu/*/cpuid - CPU information support"
486 This device gives processes access to the x86 CPUID instruction to
487 be executed on a specific processor. It is a character device
488 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
491 source "drivers/firmware/Kconfig"
494 prompt "High Memory Support"
495 default HIGHMEM4G if !X86_NUMAQ
496 default HIGHMEM64G if X86_NUMAQ
500 depends on !X86_NUMAQ
502 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
503 However, the address space of 32-bit x86 processors is only 4
504 Gigabytes large. That means that, if you have a large amount of
505 physical memory, not all of it can be "permanently mapped" by the
506 kernel. The physical memory that's not permanently mapped is called
509 If you are compiling a kernel which will never run on a machine with
510 more than 1 Gigabyte total physical RAM, answer "off" here (default
511 choice and suitable for most users). This will result in a "3GB/1GB"
512 split: 3GB are mapped so that each process sees a 3GB virtual memory
513 space and the remaining part of the 4GB virtual memory space is used
514 by the kernel to permanently map as much physical memory as
517 If the machine has between 1 and 4 Gigabytes physical RAM, then
520 If more than 4 Gigabytes is used then answer "64GB" here. This
521 selection turns Intel PAE (Physical Address Extension) mode on.
522 PAE implements 3-level paging on IA32 processors. PAE is fully
523 supported by Linux, PAE mode is implemented on all recent Intel
524 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
525 then the kernel will not boot on CPUs that don't support PAE!
527 The actual amount of total physical memory will either be
528 auto detected or can be forced by using a kernel command line option
529 such as "mem=256M". (Try "man bootparam" or see the documentation of
530 your boot loader (lilo or loadlin) about how to pass options to the
531 kernel at boot time.)
533 If unsure, say "off".
537 depends on !X86_NUMAQ
539 Select this if you have a 32-bit processor and between 1 and 4
540 gigabytes of physical RAM.
544 depends on !M386 && !M486
546 Select this if you have a 32-bit processor and more than 4
547 gigabytes of physical RAM.
552 depends on EXPERIMENTAL
553 prompt "Memory split" if EMBEDDED
556 Select the desired split between kernel and user memory.
558 If the address range available to the kernel is less than the
559 physical memory installed, the remaining memory will be available
560 as "high memory". Accessing high memory is a little more costly
561 than low memory, as it needs to be mapped into the kernel first.
562 Note that increasing the kernel address space limits the range
563 available to user programs, making the address space there
564 tighter. Selecting anything other than the default 3G/1G split
565 will also likely make your kernel incompatible with binary-only
568 If you are not absolutely sure what you are doing, leave this
572 bool "3G/1G user/kernel split"
573 config VMSPLIT_3G_OPT
575 bool "3G/1G user/kernel split (for full 1G low memory)"
577 bool "2G/2G user/kernel split"
578 config VMSPLIT_2G_OPT
580 bool "2G/2G user/kernel split (for full 2G low memory)"
582 bool "1G/3G user/kernel split"
587 default 0xB0000000 if VMSPLIT_3G_OPT
588 default 0x80000000 if VMSPLIT_2G
589 default 0x78000000 if VMSPLIT_2G_OPT
590 default 0x40000000 if VMSPLIT_1G
595 depends on HIGHMEM64G || HIGHMEM4G
600 depends on HIGHMEM64G
602 select RESOURCES_64BIT
604 # Common NUMA Features
606 bool "Numa Memory Allocation and Scheduler Support"
607 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
609 default y if (X86_NUMAQ || X86_SUMMIT)
611 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
612 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
616 default "4" if X86_NUMAQ
618 depends on NEED_MULTIPLE_NODES
620 config HAVE_ARCH_BOOTMEM_NODE
625 config ARCH_HAVE_MEMORY_PRESENT
627 depends on DISCONTIGMEM
630 config NEED_NODE_MEMMAP_SIZE
632 depends on DISCONTIGMEM || SPARSEMEM
635 config HAVE_ARCH_ALLOC_REMAP
640 config ARCH_FLATMEM_ENABLE
642 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
644 config ARCH_DISCONTIGMEM_ENABLE
648 config ARCH_DISCONTIGMEM_DEFAULT
652 config ARCH_SPARSEMEM_ENABLE
654 depends on (NUMA || (X86_PC && EXPERIMENTAL))
655 select SPARSEMEM_STATIC
657 config ARCH_SELECT_MEMORY_MODEL
659 depends on ARCH_SPARSEMEM_ENABLE
661 config ARCH_POPULATES_NODE_MAP
667 bool "Allocate 3rd-level pagetables from highmem"
668 depends on HIGHMEM4G || HIGHMEM64G
670 The VM uses one page table entry for each page of physical memory.
671 For systems with a lot of RAM, this can be wasteful of precious
672 low memory. Setting this option will put user-space page table
673 entries in high memory.
675 config MATH_EMULATION
676 bool "Math emulation"
678 Linux can emulate a math coprocessor (used for floating point
679 operations) if you don't have one. 486DX and Pentium processors have
680 a math coprocessor built in, 486SX and 386 do not, unless you added
681 a 487DX or 387, respectively. (The messages during boot time can
682 give you some hints here ["man dmesg"].) Everyone needs either a
683 coprocessor or this emulation.
685 If you don't have a math coprocessor, you need to say Y here; if you
686 say Y here even though you have a coprocessor, the coprocessor will
687 be used nevertheless. (This behavior can be changed with the kernel
688 command line option "no387", which comes handy if your coprocessor
689 is broken. Try "man bootparam" or see the documentation of your boot
690 loader (lilo or loadlin) about how to pass options to the kernel at
691 boot time.) This means that it is a good idea to say Y here if you
692 intend to use this kernel on different machines.
694 More information about the internals of the Linux math coprocessor
695 emulation can be found in <file:arch/i386/math-emu/README>.
697 If you are not sure, say Y; apart from resulting in a 66 KB bigger
698 kernel, it won't hurt.
701 bool "MTRR (Memory Type Range Register) support"
703 On Intel P6 family processors (Pentium Pro, Pentium II and later)
704 the Memory Type Range Registers (MTRRs) may be used to control
705 processor access to memory ranges. This is most useful if you have
706 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
707 allows bus write transfers to be combined into a larger transfer
708 before bursting over the PCI/AGP bus. This can increase performance
709 of image write operations 2.5 times or more. Saying Y here creates a
710 /proc/mtrr file which may be used to manipulate your processor's
711 MTRRs. Typically the X server should use this.
713 This code has a reasonably generic interface so that similar
714 control registers on other processors can be easily supported
717 The Cyrix 6x86, 6x86MX and M II processors have Address Range
718 Registers (ARRs) which provide a similar functionality to MTRRs. For
719 these, the ARRs are used to emulate the MTRRs.
720 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
721 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
722 write-combining. All of these processors are supported by this code
723 and it makes sense to say Y here if you have one of them.
725 Saying Y here also fixes a problem with buggy SMP BIOSes which only
726 set the MTRRs for the boot CPU and not for the secondary CPUs. This
727 can lead to all sorts of problems, so it's good to say Y here.
729 You can safely say Y even if your machine doesn't have MTRRs, you'll
730 just add about 9 KB to your kernel.
732 See <file:Documentation/mtrr.txt> for more information.
735 bool "Boot from EFI support"
739 This enables the kernel to boot on EFI platforms using
740 system configuration information passed to it from the firmware.
741 This also enables the kernel to use any EFI runtime services that are
742 available (such as the EFI variable services).
744 This option is only useful on systems that have EFI firmware
745 and will result in a kernel image that is ~8k larger. In addition,
746 you must use the latest ELILO loader available at
747 <http://elilo.sourceforge.net> in order to take advantage of
748 kernel initialization using EFI information (neither GRUB nor LILO know
749 anything about EFI). However, even with this option, the resultant
750 kernel should continue to boot on existing non-EFI platforms.
753 bool "Enable kernel irq balancing"
754 depends on SMP && X86_IO_APIC
757 The default yes will allow the kernel to do irq load balancing.
758 Saying no will keep the kernel from doing irq load balancing.
760 # turning this on wastes a bunch of space.
761 # Summit needs it only when NUMA is on
764 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
768 bool "Enable seccomp to safely compute untrusted bytecode"
772 This kernel feature is useful for number crunching applications
773 that may need to compute untrusted bytecode during their
774 execution. By using pipes or other transports made available to
775 the process as file descriptors supporting the read/write
776 syscalls, it's possible to isolate those applications in
777 their own address space using seccomp. Once seccomp is
778 enabled via /proc/<pid>/seccomp, it cannot be disabled
779 and the task is only allowed to execute a few safe syscalls
780 defined by each seccomp mode.
782 If unsure, say Y. Only embedded should say N here.
784 source kernel/Kconfig.hz
787 bool "kexec system call"
789 kexec is a system call that implements the ability to shutdown your
790 current kernel, and to start another kernel. It is like a reboot
791 but it is independent of the system firmware. And like a reboot
792 you can start any kernel with it, not just Linux.
794 The name comes from the similarity to the exec system call.
796 It is an ongoing process to be certain the hardware in a machine
797 is properly shutdown, so do not be surprised if this code does not
798 initially work for you. It may help to enable device hotplugging
799 support. As of this writing the exact hardware interface is
800 strongly in flux, so no good recommendation can be made.
803 bool "kernel crash dumps (EXPERIMENTAL)"
804 depends on EXPERIMENTAL
807 Generate crash dump after being started by kexec.
808 This should be normally only set in special crash dump kernels
809 which are loaded in the main kernel with kexec-tools into
810 a specially reserved region and then later executed after
811 a crash by kdump/kexec. The crash dump kernel must be compiled
812 to a memory address not used by the main kernel or BIOS using
814 For more details see Documentation/kdump/kdump.txt
816 config PHYSICAL_START
817 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
820 This gives the physical address where the kernel is loaded.
822 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
823 bzImage will decompress itself to above physical address and
824 run from there. Otherwise, bzImage will run from the address where
825 it has been loaded by the boot loader and will ignore above physical
828 In normal kdump cases one does not have to set/change this option
829 as now bzImage can be compiled as a completely relocatable image
830 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
831 address. This option is mainly useful for the folks who don't want
832 to use a bzImage for capturing the crash dump and want to use a
833 vmlinux instead. vmlinux is not relocatable hence a kernel needs
834 to be specifically compiled to run from a specific memory area
835 (normally a reserved region) and this option comes handy.
837 So if you are using bzImage for capturing the crash dump, leave
838 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
839 Otherwise if you plan to use vmlinux for capturing the crash dump
840 change this value to start of the reserved region (Typically 16MB
841 0x1000000). In other words, it can be set based on the "X" value as
842 specified in the "crashkernel=YM@XM" command line boot parameter
843 passed to the panic-ed kernel. Typically this parameter is set as
844 crashkernel=64M@16M. Please take a look at
845 Documentation/kdump/kdump.txt for more details about crash dumps.
847 Usage of bzImage for capturing the crash dump is recommended as
848 one does not have to build two kernels. Same kernel can be used
849 as production kernel and capture kernel. Above option should have
850 gone away after relocatable bzImage support is introduced. But it
851 is present because there are users out there who continue to use
852 vmlinux for dump capture. This option should go away down the
855 Don't change this unless you know what you are doing.
858 bool "Build a relocatable kernel(EXPERIMENTAL)"
859 depends on EXPERIMENTAL
861 This builds a kernel image that retains relocation information
862 so it can be loaded someplace besides the default 1MB.
863 The relocations tend to make the kernel binary about 10% larger,
864 but are discarded at runtime.
866 One use is for the kexec on panic case where the recovery kernel
867 must live at a different physical address than the primary
870 config PHYSICAL_ALIGN
871 hex "Alignment value to which kernel should be aligned"
873 range 0x2000 0x400000
875 This value puts the alignment restrictions on physical address
876 where kernel is loaded and run from. Kernel is compiled for an
877 address which meets above alignment restriction.
879 If bootloader loads the kernel at a non-aligned address and
880 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
881 address aligned to above value and run from there.
883 If bootloader loads the kernel at a non-aligned address and
884 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
885 load address and decompress itself to the address it has been
886 compiled for and run from there. The address for which kernel is
887 compiled already meets above alignment restrictions. Hence the
888 end result is that kernel runs from a physical address meeting
889 above alignment restrictions.
891 Don't change this unless you know what you are doing.
894 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
895 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
897 Say Y here to experiment with turning CPUs off and on, and to
898 enable suspend on SMP systems. CPUs can be controlled through
899 /sys/devices/system/cpu.
902 bool "Compat VDSO support"
905 Map the VDSO to the predictable old-style address too.
907 Say N here if you are running a sufficiently recent glibc
908 version (2.3.3 or later), to remove the high-mapped
909 VDSO mapping and to exclusively use the randomized VDSO.
915 config ARCH_ENABLE_MEMORY_HOTPLUG
919 menu "Power management options (ACPI, APM)"
920 depends on !X86_VOYAGER
922 source kernel/power/Kconfig
924 source "drivers/acpi/Kconfig"
927 tristate "APM (Advanced Power Management) BIOS support"
928 depends on PM && !X86_VISWS
930 APM is a BIOS specification for saving power using several different
931 techniques. This is mostly useful for battery powered laptops with
932 APM compliant BIOSes. If you say Y here, the system time will be
933 reset after a RESUME operation, the /proc/apm device will provide
934 battery status information, and user-space programs will receive
935 notification of APM "events" (e.g. battery status change).
937 If you select "Y" here, you can disable actual use of the APM
938 BIOS by passing the "apm=off" option to the kernel at boot time.
940 Note that the APM support is almost completely disabled for
941 machines with more than one CPU.
943 In order to use APM, you will need supporting software. For location
944 and more information, read <file:Documentation/pm.txt> and the
945 Battery Powered Linux mini-HOWTO, available from
946 <http://www.tldp.org/docs.html#howto>.
948 This driver does not spin down disk drives (see the hdparm(8)
949 manpage ("man 8 hdparm") for that), and it doesn't turn off
950 VESA-compliant "green" monitors.
952 This driver does not support the TI 4000M TravelMate and the ACER
953 486/DX4/75 because they don't have compliant BIOSes. Many "green"
954 desktop machines also don't have compliant BIOSes, and this driver
955 may cause those machines to panic during the boot phase.
957 Generally, if you don't have a battery in your machine, there isn't
958 much point in using this driver and you should say N. If you get
959 random kernel OOPSes or reboots that don't seem to be related to
960 anything, try disabling/enabling this option (or disabling/enabling
963 Some other things you should try when experiencing seemingly random,
966 1) make sure that you have enough swap space and that it is
968 2) pass the "no-hlt" option to the kernel
969 3) switch on floating point emulation in the kernel and pass
970 the "no387" option to the kernel
971 4) pass the "floppy=nodma" option to the kernel
972 5) pass the "mem=4M" option to the kernel (thereby disabling
973 all but the first 4 MB of RAM)
974 6) make sure that the CPU is not over clocked.
975 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
976 8) disable the cache from your BIOS settings
977 9) install a fan for the video card or exchange video RAM
978 10) install a better fan for the CPU
979 11) exchange RAM chips
980 12) exchange the motherboard.
982 To compile this driver as a module, choose M here: the
983 module will be called apm.
987 config APM_IGNORE_USER_SUSPEND
988 bool "Ignore USER SUSPEND"
990 This option will ignore USER SUSPEND requests. On machines with a
991 compliant APM BIOS, you want to say N. However, on the NEC Versa M
992 series notebooks, it is necessary to say Y because of a BIOS bug.
995 bool "Enable PM at boot time"
997 Enable APM features at boot time. From page 36 of the APM BIOS
998 specification: "When disabled, the APM BIOS does not automatically
999 power manage devices, enter the Standby State, enter the Suspend
1000 State, or take power saving steps in response to CPU Idle calls."
1001 This driver will make CPU Idle calls when Linux is idle (unless this
1002 feature is turned off -- see "Do CPU IDLE calls", below). This
1003 should always save battery power, but more complicated APM features
1004 will be dependent on your BIOS implementation. You may need to turn
1005 this option off if your computer hangs at boot time when using APM
1006 support, or if it beeps continuously instead of suspending. Turn
1007 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1008 T400CDT. This is off by default since most machines do fine without
1012 bool "Make CPU Idle calls when idle"
1014 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1015 On some machines, this can activate improved power savings, such as
1016 a slowed CPU clock rate, when the machine is idle. These idle calls
1017 are made after the idle loop has run for some length of time (e.g.,
1018 333 mS). On some machines, this will cause a hang at boot time or
1019 whenever the CPU becomes idle. (On machines with more than one CPU,
1020 this option does nothing.)
1022 config APM_DISPLAY_BLANK
1023 bool "Enable console blanking using APM"
1025 Enable console blanking using the APM. Some laptops can use this to
1026 turn off the LCD backlight when the screen blanker of the Linux
1027 virtual console blanks the screen. Note that this is only used by
1028 the virtual console screen blanker, and won't turn off the backlight
1029 when using the X Window system. This also doesn't have anything to
1030 do with your VESA-compliant power-saving monitor. Further, this
1031 option doesn't work for all laptops -- it might not turn off your
1032 backlight at all, or it might print a lot of errors to the console,
1033 especially if you are using gpm.
1035 config APM_ALLOW_INTS
1036 bool "Allow interrupts during APM BIOS calls"
1038 Normally we disable external interrupts while we are making calls to
1039 the APM BIOS as a measure to lessen the effects of a badly behaving
1040 BIOS implementation. The BIOS should reenable interrupts if it
1041 needs to. Unfortunately, some BIOSes do not -- especially those in
1042 many of the newer IBM Thinkpads. If you experience hangs when you
1043 suspend, try setting this to Y. Otherwise, say N.
1045 config APM_REAL_MODE_POWER_OFF
1046 bool "Use real mode APM BIOS call to power off"
1048 Use real mode APM BIOS calls to switch off the computer. This is
1049 a work-around for a number of buggy BIOSes. Switch this option on if
1050 your computer crashes instead of powering off properly.
1054 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1058 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1061 bool "PCI support" if !X86_VISWS
1062 depends on !X86_VOYAGER
1063 default y if X86_VISWS
1064 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1066 Find out whether you have a PCI motherboard. PCI is the name of a
1067 bus system, i.e. the way the CPU talks to the other stuff inside
1068 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1069 VESA. If you have PCI, say Y, otherwise N.
1071 The PCI-HOWTO, available from
1072 <http://www.tldp.org/docs.html#howto>, contains valuable
1073 information about which PCI hardware does work under Linux and which
1077 prompt "PCI access mode"
1078 depends on PCI && !X86_VISWS
1081 On PCI systems, the BIOS can be used to detect the PCI devices and
1082 determine their configuration. However, some old PCI motherboards
1083 have BIOS bugs and may crash if this is done. Also, some embedded
1084 PCI-based systems don't have any BIOS at all. Linux can also try to
1085 detect the PCI hardware directly without using the BIOS.
1087 With this option, you can specify how Linux should detect the
1088 PCI devices. If you choose "BIOS", the BIOS will be used,
1089 if you choose "Direct", the BIOS won't be used, and if you
1090 choose "MMConfig", then PCI Express MMCONFIG will be used.
1091 If you choose "Any", the kernel will try MMCONFIG, then the
1092 direct access method and falls back to the BIOS if that doesn't
1093 work. If unsure, go with the default, which is "Any".
1098 config PCI_GOMMCONFIG
1111 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1116 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1121 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1124 source "drivers/pci/pcie/Kconfig"
1126 source "drivers/pci/Kconfig"
1134 depends on !(X86_VOYAGER || X86_VISWS)
1136 Find out whether you have ISA slots on your motherboard. ISA is the
1137 name of a bus system, i.e. the way the CPU talks to the other stuff
1138 inside your box. Other bus systems are PCI, EISA, MicroChannel
1139 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1140 newer boards don't support it. If you have ISA, say Y, otherwise N.
1146 The Extended Industry Standard Architecture (EISA) bus was
1147 developed as an open alternative to the IBM MicroChannel bus.
1149 The EISA bus provided some of the features of the IBM MicroChannel
1150 bus while maintaining backward compatibility with cards made for
1151 the older ISA bus. The EISA bus saw limited use between 1988 and
1152 1995 when it was made obsolete by the PCI bus.
1154 Say Y here if you are building a kernel for an EISA-based machine.
1158 source "drivers/eisa/Kconfig"
1161 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1162 default y if X86_VOYAGER
1164 MicroChannel Architecture is found in some IBM PS/2 machines and
1165 laptops. It is a bus system similar to PCI or ISA. See
1166 <file:Documentation/mca.txt> (and especially the web page given
1167 there) before attempting to build an MCA bus kernel.
1169 source "drivers/mca/Kconfig"
1172 tristate "NatSemi SCx200 support"
1173 depends on !X86_VOYAGER
1175 This provides basic support for National Semiconductor's
1176 (now AMD's) Geode processors. The driver probes for the
1177 PCI-IDs of several on-chip devices, so its a good dependency
1178 for other scx200_* drivers.
1180 If compiled as a module, the driver is named scx200.
1182 config SCx200HR_TIMER
1183 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1184 depends on SCx200 && GENERIC_TIME
1187 This driver provides a clocksource built upon the on-chip
1188 27MHz high-resolution timer. Its also a workaround for
1189 NSC Geode SC-1100's buggy TSC, which loses time when the
1190 processor goes idle (as is done by the scheduler). The
1191 other workaround is idle=poll boot option.
1195 depends on AGP_AMD64
1197 source "drivers/pcmcia/Kconfig"
1199 source "drivers/pci/hotplug/Kconfig"
1203 menu "Executable file formats"
1205 source "fs/Kconfig.binfmt"
1209 source "net/Kconfig"
1211 source "drivers/Kconfig"
1215 menu "Instrumentation Support"
1216 depends on EXPERIMENTAL
1218 source "arch/i386/oprofile/Kconfig"
1221 bool "Kprobes (EXPERIMENTAL)"
1222 depends on KALLSYMS && EXPERIMENTAL && MODULES
1224 Kprobes allows you to trap at almost any kernel address and
1225 execute a callback function. register_kprobe() establishes
1226 a probepoint and specifies the callback. Kprobes is useful
1227 for kernel debugging, non-intrusive instrumentation and testing.
1228 If in doubt, say "N".
1231 source "arch/i386/Kconfig.debug"
1233 source "security/Kconfig"
1235 source "crypto/Kconfig"
1237 source "lib/Kconfig"
1240 # Use the generic interrupt handling code in kernel/irq/:
1242 config GENERIC_HARDIRQS
1246 config GENERIC_IRQ_PROBE
1250 config GENERIC_PENDING_IRQ
1252 depends on GENERIC_HARDIRQS && SMP
1257 depends on SMP && !X86_VOYAGER
1262 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1265 config X86_BIOS_REBOOT
1267 depends on !(X86_VISWS || X86_VOYAGER)
1270 config X86_TRAMPOLINE
1272 depends on X86_SMP || (X86_VOYAGER && SMP)
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