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 GENERIC_CMOS_UPDATE
25 config CLOCKSOURCE_WATCHDOG
29 config GENERIC_CLOCKEVENTS
33 config GENERIC_CLOCKEVENTS_BROADCAST
36 depends on X86_LOCAL_APIC
38 config LOCKDEP_SUPPORT
42 config STACKTRACE_SUPPORT
46 config SEMAPHORE_SLEEPERS
69 config GENERIC_ISA_DMA
82 config GENERIC_HWEIGHT
86 config ARCH_MAY_HAVE_PC_FDC
96 menu "Processor type and features"
98 source "kernel/time/Kconfig"
101 bool "Symmetric multi-processing support"
103 This enables support for systems with more than one CPU. If you have
104 a system with only one CPU, like most personal computers, say N. If
105 you have a system with more than one CPU, say Y.
107 If you say N here, the kernel will run on single and multiprocessor
108 machines, but will use only one CPU of a multiprocessor machine. If
109 you say Y here, the kernel will run on many, but not all,
110 singleprocessor machines. On a singleprocessor machine, the kernel
111 will run faster if you say N here.
113 Note that if you say Y here and choose architecture "586" or
114 "Pentium" under "Processor family", the kernel will not work on 486
115 architectures. Similarly, multiprocessor kernels for the "PPro"
116 architecture may not work on all Pentium based boards.
118 People using multiprocessor machines who say Y here should also say
119 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
120 Management" code will be disabled if you say Y here.
122 See also the <file:Documentation/smp.txt>,
123 <file:Documentation/i386/IO-APIC.txt>,
124 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
125 <http://www.tldp.org/docs.html#howto>.
127 If you don't know what to do here, say N.
130 prompt "Subarchitecture Type"
136 Choose this option if your computer is a standard PC or compatible.
142 Select this for an AMD Elan processor.
144 Do not use this option for K6/Athlon/Opteron processors!
146 If unsure, choose "PC-compatible" instead.
151 select SMP if !BROKEN
153 Voyager is an MCA-based 32-way capable SMP architecture proprietary
154 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
158 If you do not specifically know you have a Voyager based machine,
159 say N here, otherwise the kernel you build will not be bootable.
162 bool "NUMAQ (IBM/Sequent)"
167 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
168 multiquad box. This changes the way that processors are bootstrapped,
169 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
170 You will need a new lynxer.elf file to flash your firmware with - send
171 email to <Martin.Bligh@us.ibm.com>.
174 bool "Summit/EXA (IBM x440)"
175 depends on X86_32 && SMP
177 This option is needed for IBM systems that use the Summit/EXA chipset.
178 In particular, it is needed for the x440.
180 If you don't have one of these computers, you should say N here.
181 If you want to build a NUMA kernel, you must select ACPI.
184 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
185 depends on X86_32 && SMP
187 This option is needed for the systems that have more than 8 CPUs
188 and if the system is not of any sub-arch type above.
190 If you don't have such a system, you should say N here.
193 bool "SGI 320/540 (Visual Workstation)"
196 The SGI Visual Workstation series is an IA32-based workstation
197 based on SGI systems chips with some legacy PC hardware attached.
199 Say Y here to create a kernel to run on the SGI 320 or 540.
201 A kernel compiled for the Visual Workstation will not run on PCs
202 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
204 config X86_GENERICARCH
205 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
208 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
209 It is intended for a generic binary kernel.
210 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
213 bool "Support for Unisys ES7000 IA32 series"
214 depends on X86_32 && SMP
216 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
217 supposed to run on an IA32-based Unisys ES7000 system.
218 Only choose this option if you have such a system, otherwise you
223 config SCHED_NO_NO_OMIT_FRAME_POINTER
224 bool "Single-depth WCHAN output"
228 Calculate simpler /proc/<PID>/wchan values. If this option
229 is disabled then wchan values will recurse back to the
230 caller function. This provides more accurate wchan values,
231 at the expense of slightly more scheduling overhead.
233 If in doubt, say "Y".
237 depends on X86_32 && !(X86_VISWS || X86_VOYAGER)
239 This changes the kernel so it can modify itself when it is run
240 under a hypervisor, potentially improving performance significantly
241 over full virtualization. However, when run without a hypervisor
242 the kernel is theoretically slower and slightly larger.
244 menuconfig PARAVIRT_GUEST
245 bool "Paravirtualized guest support"
248 Say Y here to get to see options related to running Linux under
249 various hypervisors. This option alone does not add any kernel code.
251 If you say N, all options in this submenu will be skipped and disabled.
255 source "arch/x86/xen/Kconfig"
258 bool "VMI Guest support"
260 depends on !(X86_VISWS || X86_VOYAGER)
262 VMI provides a paravirtualized interface to the VMware ESX server
263 (it could be used by other hypervisors in theory too, but is not
264 at the moment), by linking the kernel to a GPL-ed ROM module
265 provided by the hypervisor.
267 source "arch/x86/lguest/Kconfig"
274 depends on X86_32 && ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
277 config HAVE_ARCH_PARSE_SRAT
282 config X86_SUMMIT_NUMA
285 depends on X86_32 && NUMA && (X86_SUMMIT || X86_GENERICARCH)
287 config X86_CYCLONE_TIMER
290 depends on X86_32 && X86_SUMMIT || X86_GENERICARCH
292 config ES7000_CLUSTERED_APIC
295 depends on SMP && X86_ES7000 && MPENTIUMIII
297 source "arch/x86/Kconfig.cpu"
301 prompt "HPET Timer Support" if X86_32
303 This enables the use of the HPET for the kernel's internal timer.
304 HPET is the next generation timer replacing legacy 8254s.
305 You can safely choose Y here. However, HPET will only be
306 activated if the platform and the BIOS support this feature.
307 Otherwise the 8254 will be used for timing services.
309 Choose N to continue using the legacy 8254 timer.
311 config HPET_EMULATE_RTC
313 depends on HPET_TIMER && RTC=y
317 int "Maximum number of CPUs (2-255)"
320 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
323 This allows you to specify the maximum number of CPUs which this
324 kernel will support. The maximum supported value is 255 and the
325 minimum value which makes sense is 2.
327 This is purely to save memory - each supported CPU adds
328 approximately eight kilobytes to the kernel image.
331 bool "SMT (Hyperthreading) scheduler support"
334 SMT scheduler support improves the CPU scheduler's decision making
335 when dealing with Intel Pentium 4 chips with HyperThreading at a
336 cost of slightly increased overhead in some places. If unsure say
340 bool "Multi-core scheduler support"
344 Multi-core scheduler support improves the CPU scheduler's decision
345 making when dealing with multi-core CPU chips at a cost of slightly
346 increased overhead in some places. If unsure say N here.
348 source "kernel/Kconfig.preempt"
351 bool "Local APIC support on uniprocessors"
352 depends on X86_32 && !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
354 A local APIC (Advanced Programmable Interrupt Controller) is an
355 integrated interrupt controller in the CPU. If you have a single-CPU
356 system which has a processor with a local APIC, you can say Y here to
357 enable and use it. If you say Y here even though your machine doesn't
358 have a local APIC, then the kernel will still run with no slowdown at
359 all. The local APIC supports CPU-generated self-interrupts (timer,
360 performance counters), and the NMI watchdog which detects hard
364 bool "IO-APIC support on uniprocessors"
365 depends on X86_UP_APIC
367 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
368 SMP-capable replacement for PC-style interrupt controllers. Most
369 SMP systems and many recent uniprocessor systems have one.
371 If you have a single-CPU system with an IO-APIC, you can say Y here
372 to use it. If you say Y here even though your machine doesn't have
373 an IO-APIC, then the kernel will still run with no slowdown at all.
375 config X86_LOCAL_APIC
377 depends on X86_32 && (X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH)
382 depends on X86_32 && (X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH)
385 config X86_VISWS_APIC
387 depends on X86_32 && X86_VISWS
391 bool "Machine Check Exception"
392 depends on !X86_VOYAGER
394 Machine Check Exception support allows the processor to notify the
395 kernel if it detects a problem (e.g. overheating, component failure).
396 The action the kernel takes depends on the severity of the problem,
397 ranging from a warning message on the console, to halting the machine.
398 Your processor must be a Pentium or newer to support this - check the
399 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
400 have a design flaw which leads to false MCE events - hence MCE is
401 disabled on all P5 processors, unless explicitly enabled with "mce"
402 as a boot argument. Similarly, if MCE is built in and creates a
403 problem on some new non-standard machine, you can boot with "nomce"
404 to disable it. MCE support simply ignores non-MCE processors like
405 the 386 and 486, so nearly everyone can say Y here.
407 config X86_MCE_NONFATAL
408 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
409 depends on X86_32 && X86_MCE
411 Enabling this feature starts a timer that triggers every 5 seconds which
412 will look at the machine check registers to see if anything happened.
413 Non-fatal problems automatically get corrected (but still logged).
414 Disable this if you don't want to see these messages.
415 Seeing the messages this option prints out may be indicative of dying
416 or out-of-spec (ie, overclocked) hardware.
417 This option only does something on certain CPUs.
418 (AMD Athlon/Duron and Intel Pentium 4)
420 config X86_MCE_P4THERMAL
421 bool "check for P4 thermal throttling interrupt."
422 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
424 Enabling this feature will cause a message to be printed when the P4
425 enters thermal throttling.
428 bool "Enable VM86 support" if EMBEDDED
432 This option is required by programs like DOSEMU to run 16-bit legacy
433 code on X86 processors. It also may be needed by software like
434 XFree86 to initialize some video cards via BIOS. Disabling this
435 option saves about 6k.
438 tristate "Toshiba Laptop support"
441 This adds a driver to safely access the System Management Mode of
442 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
443 not work on models with a Phoenix BIOS. The System Management Mode
444 is used to set the BIOS and power saving options on Toshiba portables.
446 For information on utilities to make use of this driver see the
447 Toshiba Linux utilities web site at:
448 <http://www.buzzard.org.uk/toshiba/>.
450 Say Y if you intend to run this kernel on a Toshiba portable.
454 tristate "Dell laptop support"
457 This adds a driver to safely access the System Management Mode
458 of the CPU on the Dell Inspiron 8000. The System Management Mode
459 is used to read cpu temperature and cooling fan status and to
460 control the fans on the I8K portables.
462 This driver has been tested only on the Inspiron 8000 but it may
463 also work with other Dell laptops. You can force loading on other
464 models by passing the parameter `force=1' to the module. Use at
467 For information on utilities to make use of this driver see the
468 I8K Linux utilities web site at:
469 <http://people.debian.org/~dz/i8k/>
471 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
474 config X86_REBOOTFIXUPS
475 bool "Enable X86 board specific fixups for reboot"
476 depends on X86_32 && X86
479 This enables chipset and/or board specific fixups to be done
480 in order to get reboot to work correctly. This is only needed on
481 some combinations of hardware and BIOS. The symptom, for which
482 this config is intended, is when reboot ends with a stalled/hung
485 Currently, the only fixup is for the Geode machines using
486 CS5530A and CS5536 chipsets.
488 Say Y if you want to enable the fixup. Currently, it's safe to
489 enable this option even if you don't need it.
493 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
496 If you say Y here, you will be able to update the microcode on
497 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
498 Pentium III, Pentium 4, Xeon etc. You will obviously need the
499 actual microcode binary data itself which is not shipped with the
502 For latest news and information on obtaining all the required
503 ingredients for this driver, check:
504 <http://www.urbanmyth.org/microcode/>.
506 To compile this driver as a module, choose M here: the
507 module will be called microcode.
509 config MICROCODE_OLD_INTERFACE
515 tristate "/dev/cpu/*/msr - Model-specific register support"
517 This device gives privileged processes access to the x86
518 Model-Specific Registers (MSRs). It is a character device with
519 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
520 MSR accesses are directed to a specific CPU on multi-processor
524 tristate "/dev/cpu/*/cpuid - CPU information support"
526 This device gives processes access to the x86 CPUID instruction to
527 be executed on a specific processor. It is a character device
528 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
532 prompt "High Memory Support"
533 default HIGHMEM4G if !X86_NUMAQ
534 default HIGHMEM64G if X86_NUMAQ
539 depends on !X86_NUMAQ
541 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
542 However, the address space of 32-bit x86 processors is only 4
543 Gigabytes large. That means that, if you have a large amount of
544 physical memory, not all of it can be "permanently mapped" by the
545 kernel. The physical memory that's not permanently mapped is called
548 If you are compiling a kernel which will never run on a machine with
549 more than 1 Gigabyte total physical RAM, answer "off" here (default
550 choice and suitable for most users). This will result in a "3GB/1GB"
551 split: 3GB are mapped so that each process sees a 3GB virtual memory
552 space and the remaining part of the 4GB virtual memory space is used
553 by the kernel to permanently map as much physical memory as
556 If the machine has between 1 and 4 Gigabytes physical RAM, then
559 If more than 4 Gigabytes is used then answer "64GB" here. This
560 selection turns Intel PAE (Physical Address Extension) mode on.
561 PAE implements 3-level paging on IA32 processors. PAE is fully
562 supported by Linux, PAE mode is implemented on all recent Intel
563 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
564 then the kernel will not boot on CPUs that don't support PAE!
566 The actual amount of total physical memory will either be
567 auto detected or can be forced by using a kernel command line option
568 such as "mem=256M". (Try "man bootparam" or see the documentation of
569 your boot loader (lilo or loadlin) about how to pass options to the
570 kernel at boot time.)
572 If unsure, say "off".
576 depends on !X86_NUMAQ
578 Select this if you have a 32-bit processor and between 1 and 4
579 gigabytes of physical RAM.
583 depends on !M386 && !M486
586 Select this if you have a 32-bit processor and more than 4
587 gigabytes of physical RAM.
592 depends on EXPERIMENTAL
593 prompt "Memory split" if EMBEDDED
597 Select the desired split between kernel and user memory.
599 If the address range available to the kernel is less than the
600 physical memory installed, the remaining memory will be available
601 as "high memory". Accessing high memory is a little more costly
602 than low memory, as it needs to be mapped into the kernel first.
603 Note that increasing the kernel address space limits the range
604 available to user programs, making the address space there
605 tighter. Selecting anything other than the default 3G/1G split
606 will also likely make your kernel incompatible with binary-only
609 If you are not absolutely sure what you are doing, leave this
613 bool "3G/1G user/kernel split"
614 config VMSPLIT_3G_OPT
616 bool "3G/1G user/kernel split (for full 1G low memory)"
618 bool "2G/2G user/kernel split"
619 config VMSPLIT_2G_OPT
621 bool "2G/2G user/kernel split (for full 2G low memory)"
623 bool "1G/3G user/kernel split"
628 default 0xB0000000 if VMSPLIT_3G_OPT
629 default 0x80000000 if VMSPLIT_2G
630 default 0x78000000 if VMSPLIT_2G_OPT
631 default 0x40000000 if VMSPLIT_1G
637 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
641 bool "PAE (Physical Address Extension) Support"
643 depends on X86_32 && !HIGHMEM4G
644 select RESOURCES_64BIT
646 PAE is required for NX support, and furthermore enables
647 larger swapspace support for non-overcommit purposes. It
648 has the cost of more pagetable lookup overhead, and also
649 consumes more pagetable space per process.
651 # Common NUMA Features
653 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
654 depends on X86_32 && SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL
656 default y if (X86_NUMAQ || X86_SUMMIT)
658 NUMA support for i386. This is currently highly experimental
659 and should be only used for kernel development. It might also
662 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
663 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
667 default "4" if X86_NUMAQ
669 depends on NEED_MULTIPLE_NODES
671 config HAVE_ARCH_BOOTMEM_NODE
673 depends on X86_32 && NUMA
676 config ARCH_HAVE_MEMORY_PRESENT
678 depends on X86_32 && DISCONTIGMEM
681 config NEED_NODE_MEMMAP_SIZE
683 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
686 config HAVE_ARCH_ALLOC_REMAP
688 depends on X86_32 && NUMA
691 config ARCH_FLATMEM_ENABLE
693 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && X86_PC
695 config ARCH_DISCONTIGMEM_ENABLE
699 config ARCH_DISCONTIGMEM_DEFAULT
703 config ARCH_SPARSEMEM_ENABLE
705 depends on (NUMA || (X86_PC && EXPERIMENTAL))
706 select SPARSEMEM_STATIC if X86_32
708 config ARCH_SELECT_MEMORY_MODEL
710 depends on X86_32 && ARCH_SPARSEMEM_ENABLE
712 config ARCH_POPULATES_NODE_MAP
718 bool "Allocate 3rd-level pagetables from highmem"
719 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
721 The VM uses one page table entry for each page of physical memory.
722 For systems with a lot of RAM, this can be wasteful of precious
723 low memory. Setting this option will put user-space page table
724 entries in high memory.
726 config MATH_EMULATION
728 prompt "Math emulation" if X86_32
730 Linux can emulate a math coprocessor (used for floating point
731 operations) if you don't have one. 486DX and Pentium processors have
732 a math coprocessor built in, 486SX and 386 do not, unless you added
733 a 487DX or 387, respectively. (The messages during boot time can
734 give you some hints here ["man dmesg"].) Everyone needs either a
735 coprocessor or this emulation.
737 If you don't have a math coprocessor, you need to say Y here; if you
738 say Y here even though you have a coprocessor, the coprocessor will
739 be used nevertheless. (This behavior can be changed with the kernel
740 command line option "no387", which comes handy if your coprocessor
741 is broken. Try "man bootparam" or see the documentation of your boot
742 loader (lilo or loadlin) about how to pass options to the kernel at
743 boot time.) This means that it is a good idea to say Y here if you
744 intend to use this kernel on different machines.
746 More information about the internals of the Linux math coprocessor
747 emulation can be found in <file:arch/x86/math-emu/README>.
749 If you are not sure, say Y; apart from resulting in a 66 KB bigger
750 kernel, it won't hurt.
753 bool "MTRR (Memory Type Range Register) support"
755 On Intel P6 family processors (Pentium Pro, Pentium II and later)
756 the Memory Type Range Registers (MTRRs) may be used to control
757 processor access to memory ranges. This is most useful if you have
758 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
759 allows bus write transfers to be combined into a larger transfer
760 before bursting over the PCI/AGP bus. This can increase performance
761 of image write operations 2.5 times or more. Saying Y here creates a
762 /proc/mtrr file which may be used to manipulate your processor's
763 MTRRs. Typically the X server should use this.
765 This code has a reasonably generic interface so that similar
766 control registers on other processors can be easily supported
769 The Cyrix 6x86, 6x86MX and M II processors have Address Range
770 Registers (ARRs) which provide a similar functionality to MTRRs. For
771 these, the ARRs are used to emulate the MTRRs.
772 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
773 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
774 write-combining. All of these processors are supported by this code
775 and it makes sense to say Y here if you have one of them.
777 Saying Y here also fixes a problem with buggy SMP BIOSes which only
778 set the MTRRs for the boot CPU and not for the secondary CPUs. This
779 can lead to all sorts of problems, so it's good to say Y here.
781 You can safely say Y even if your machine doesn't have MTRRs, you'll
782 just add about 9 KB to your kernel.
784 See <file:Documentation/mtrr.txt> for more information.
787 bool "Boot from EFI support"
788 depends on X86_32 && ACPI
791 This enables the kernel to boot on EFI platforms using
792 system configuration information passed to it from the firmware.
793 This also enables the kernel to use any EFI runtime services that are
794 available (such as the EFI variable services).
796 This option is only useful on systems that have EFI firmware
797 and will result in a kernel image that is ~8k larger. In addition,
798 you must use the latest ELILO loader available at
799 <http://elilo.sourceforge.net> in order to take advantage of
800 kernel initialization using EFI information (neither GRUB nor LILO know
801 anything about EFI). However, even with this option, the resultant
802 kernel should continue to boot on existing non-EFI platforms.
805 bool "Enable kernel irq balancing"
806 depends on X86_32 && SMP && X86_IO_APIC
809 The default yes will allow the kernel to do irq load balancing.
810 Saying no will keep the kernel from doing irq load balancing.
812 # turning this on wastes a bunch of space.
813 # Summit needs it only when NUMA is on
816 depends on X86_32 && (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
820 bool "Enable seccomp to safely compute untrusted bytecode"
824 This kernel feature is useful for number crunching applications
825 that may need to compute untrusted bytecode during their
826 execution. By using pipes or other transports made available to
827 the process as file descriptors supporting the read/write
828 syscalls, it's possible to isolate those applications in
829 their own address space using seccomp. Once seccomp is
830 enabled via /proc/<pid>/seccomp, it cannot be disabled
831 and the task is only allowed to execute a few safe syscalls
832 defined by each seccomp mode.
834 If unsure, say Y. Only embedded should say N here.
836 source kernel/Kconfig.hz
839 bool "kexec system call"
841 kexec is a system call that implements the ability to shutdown your
842 current kernel, and to start another kernel. It is like a reboot
843 but it is independent of the system firmware. And like a reboot
844 you can start any kernel with it, not just Linux.
846 The name comes from the similarity to the exec system call.
848 It is an ongoing process to be certain the hardware in a machine
849 is properly shutdown, so do not be surprised if this code does not
850 initially work for you. It may help to enable device hotplugging
851 support. As of this writing the exact hardware interface is
852 strongly in flux, so no good recommendation can be made.
855 bool "kernel crash dumps (EXPERIMENTAL)"
856 depends on EXPERIMENTAL
859 Generate crash dump after being started by kexec.
860 This should be normally only set in special crash dump kernels
861 which are loaded in the main kernel with kexec-tools into
862 a specially reserved region and then later executed after
863 a crash by kdump/kexec. The crash dump kernel must be compiled
864 to a memory address not used by the main kernel or BIOS using
865 PHYSICAL_START, or it must be built as a relocatable image
866 (CONFIG_RELOCATABLE=y).
867 For more details see Documentation/kdump/kdump.txt
869 config PHYSICAL_START
870 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
871 default "0x1000000" if X86_NUMAQ
874 This gives the physical address where the kernel is loaded.
876 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
877 bzImage will decompress itself to above physical address and
878 run from there. Otherwise, bzImage will run from the address where
879 it has been loaded by the boot loader and will ignore above physical
882 In normal kdump cases one does not have to set/change this option
883 as now bzImage can be compiled as a completely relocatable image
884 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
885 address. This option is mainly useful for the folks who don't want
886 to use a bzImage for capturing the crash dump and want to use a
887 vmlinux instead. vmlinux is not relocatable hence a kernel needs
888 to be specifically compiled to run from a specific memory area
889 (normally a reserved region) and this option comes handy.
891 So if you are using bzImage for capturing the crash dump, leave
892 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
893 Otherwise if you plan to use vmlinux for capturing the crash dump
894 change this value to start of the reserved region (Typically 16MB
895 0x1000000). In other words, it can be set based on the "X" value as
896 specified in the "crashkernel=YM@XM" command line boot parameter
897 passed to the panic-ed kernel. Typically this parameter is set as
898 crashkernel=64M@16M. Please take a look at
899 Documentation/kdump/kdump.txt for more details about crash dumps.
901 Usage of bzImage for capturing the crash dump is recommended as
902 one does not have to build two kernels. Same kernel can be used
903 as production kernel and capture kernel. Above option should have
904 gone away after relocatable bzImage support is introduced. But it
905 is present because there are users out there who continue to use
906 vmlinux for dump capture. This option should go away down the
909 Don't change this unless you know what you are doing.
912 bool "Build a relocatable kernel (EXPERIMENTAL)"
913 depends on EXPERIMENTAL
915 This builds a kernel image that retains relocation information
916 so it can be loaded someplace besides the default 1MB.
917 The relocations tend to make the kernel binary about 10% larger,
918 but are discarded at runtime.
920 One use is for the kexec on panic case where the recovery kernel
921 must live at a different physical address than the primary
924 config PHYSICAL_ALIGN
926 prompt "Alignment value to which kernel should be aligned" if X86_32
928 range 0x2000 0x400000
930 This value puts the alignment restrictions on physical address
931 where kernel is loaded and run from. Kernel is compiled for an
932 address which meets above alignment restriction.
934 If bootloader loads the kernel at a non-aligned address and
935 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
936 address aligned to above value and run from there.
938 If bootloader loads the kernel at a non-aligned address and
939 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
940 load address and decompress itself to the address it has been
941 compiled for and run from there. The address for which kernel is
942 compiled already meets above alignment restrictions. Hence the
943 end result is that kernel runs from a physical address meeting
944 above alignment restrictions.
946 Don't change this unless you know what you are doing.
949 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
950 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
952 Say Y here to experiment with turning CPUs off and on, and to
953 enable suspend on SMP systems. CPUs can be controlled through
954 /sys/devices/system/cpu.
957 bool "Compat VDSO support"
961 Map the VDSO to the predictable old-style address too.
963 Say N here if you are running a sufficiently recent glibc
964 version (2.3.3 or later), to remove the high-mapped
965 VDSO mapping and to exclusively use the randomized VDSO.
971 config ARCH_ENABLE_MEMORY_HOTPLUG
977 # Use the generic interrupt handling code in kernel/irq/:
979 config GENERIC_HARDIRQS
983 config GENERIC_IRQ_PROBE
987 config GENERIC_PENDING_IRQ
989 depends on GENERIC_HARDIRQS && SMP
994 depends on X86_32 && SMP && !X86_VOYAGER
999 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1002 config X86_BIOS_REBOOT
1004 depends on X86_32 && !(X86_VISWS || X86_VOYAGER)
1007 config X86_TRAMPOLINE
1009 depends on X86_SMP || (X86_VOYAGER && SMP)
1015 source "arch/x86/Kconfig"
projects / linux-2.6 / blob