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.
141 Select this for an AMD Elan processor.
143 Do not use this option for K6/Athlon/Opteron processors!
145 If unsure, choose "PC-compatible" instead.
149 select SMP if !BROKEN
151 Voyager is an MCA-based 32-way capable SMP architecture proprietary
152 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
156 If you do not specifically know you have a Voyager based machine,
157 say N here, otherwise the kernel you build will not be bootable.
160 bool "NUMAQ (IBM/Sequent)"
164 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
165 multiquad box. This changes the way that processors are bootstrapped,
166 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
167 You will need a new lynxer.elf file to flash your firmware with - send
168 email to <Martin.Bligh@us.ibm.com>.
171 bool "Summit/EXA (IBM x440)"
174 This option is needed for IBM systems that use the Summit/EXA chipset.
175 In particular, it is needed for the x440.
177 If you don't have one of these computers, you should say N here.
178 If you want to build a NUMA kernel, you must select ACPI.
181 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
184 This option is needed for the systems that have more than 8 CPUs
185 and if the system is not of any sub-arch type above.
187 If you don't have such a system, you should say N here.
190 bool "SGI 320/540 (Visual Workstation)"
192 The SGI Visual Workstation series is an IA32-based workstation
193 based on SGI systems chips with some legacy PC hardware attached.
195 Say Y here to create a kernel to run on the SGI 320 or 540.
197 A kernel compiled for the Visual Workstation will not run on PCs
198 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
200 config X86_GENERICARCH
201 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
203 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
204 It is intended for a generic binary kernel.
205 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
208 bool "Support for Unisys ES7000 IA32 series"
211 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
212 supposed to run on an IA32-based Unisys ES7000 system.
213 Only choose this option if you have such a system, otherwise you
218 config SCHED_NO_NO_OMIT_FRAME_POINTER
219 bool "Single-depth WCHAN output"
222 Calculate simpler /proc/<PID>/wchan values. If this option
223 is disabled then wchan values will recurse back to the
224 caller function. This provides more accurate wchan values,
225 at the expense of slightly more scheduling overhead.
227 If in doubt, say "Y".
231 depends on !(X86_VISWS || X86_VOYAGER)
233 This changes the kernel so it can modify itself when it is run
234 under a hypervisor, potentially improving performance significantly
235 over full virtualization. However, when run without a hypervisor
236 the kernel is theoretically slower and slightly larger.
238 menuconfig PARAVIRT_GUEST
239 bool "Paravirtualized guest support"
241 Say Y here to get to see options related to running Linux under
242 various hypervisors. This option alone does not add any kernel code.
244 If you say N, all options in this submenu will be skipped and disabled.
248 source "arch/x86/xen/Kconfig"
251 bool "VMI Guest support"
253 depends on !(X86_VISWS || X86_VOYAGER)
255 VMI provides a paravirtualized interface to the VMware ESX server
256 (it could be used by other hypervisors in theory too, but is not
257 at the moment), by linking the kernel to a GPL-ed ROM module
258 provided by the hypervisor.
260 source "arch/x86/lguest/Kconfig"
267 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
270 config HAVE_ARCH_PARSE_SRAT
275 config X86_SUMMIT_NUMA
278 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
280 config X86_CYCLONE_TIMER
283 depends on X86_SUMMIT || X86_GENERICARCH
285 config ES7000_CLUSTERED_APIC
288 depends on SMP && X86_ES7000 && MPENTIUMIII
290 source "arch/i386/Kconfig.cpu"
293 bool "HPET Timer Support"
295 This enables the use of the HPET for the kernel's internal timer.
296 HPET is the next generation timer replacing legacy 8254s.
297 You can safely choose Y here. However, HPET will only be
298 activated if the platform and the BIOS support this feature.
299 Otherwise the 8254 will be used for timing services.
301 Choose N to continue using the legacy 8254 timer.
303 config HPET_EMULATE_RTC
305 depends on HPET_TIMER && RTC=y
309 int "Maximum number of CPUs (2-255)"
312 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
315 This allows you to specify the maximum number of CPUs which this
316 kernel will support. The maximum supported value is 255 and the
317 minimum value which makes sense is 2.
319 This is purely to save memory - each supported CPU adds
320 approximately eight kilobytes to the kernel image.
323 bool "SMT (Hyperthreading) scheduler support"
326 SMT scheduler support improves the CPU scheduler's decision making
327 when dealing with Intel Pentium 4 chips with HyperThreading at a
328 cost of slightly increased overhead in some places. If unsure say
332 bool "Multi-core scheduler support"
336 Multi-core scheduler support improves the CPU scheduler's decision
337 making when dealing with multi-core CPU chips at a cost of slightly
338 increased overhead in some places. If unsure say N here.
340 source "kernel/Kconfig.preempt"
343 bool "Local APIC support on uniprocessors"
344 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
346 A local APIC (Advanced Programmable Interrupt Controller) is an
347 integrated interrupt controller in the CPU. If you have a single-CPU
348 system which has a processor with a local APIC, you can say Y here to
349 enable and use it. If you say Y here even though your machine doesn't
350 have a local APIC, then the kernel will still run with no slowdown at
351 all. The local APIC supports CPU-generated self-interrupts (timer,
352 performance counters), and the NMI watchdog which detects hard
356 bool "IO-APIC support on uniprocessors"
357 depends on X86_UP_APIC
359 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
360 SMP-capable replacement for PC-style interrupt controllers. Most
361 SMP systems and many recent uniprocessor systems have one.
363 If you have a single-CPU system with an IO-APIC, you can say Y here
364 to use it. If you say Y here even though your machine doesn't have
365 an IO-APIC, then the kernel will still run with no slowdown at all.
367 config X86_LOCAL_APIC
369 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
374 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
377 config X86_VISWS_APIC
383 bool "Machine Check Exception"
384 depends on !X86_VOYAGER
386 Machine Check Exception support allows the processor to notify the
387 kernel if it detects a problem (e.g. overheating, component failure).
388 The action the kernel takes depends on the severity of the problem,
389 ranging from a warning message on the console, to halting the machine.
390 Your processor must be a Pentium or newer to support this - check the
391 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
392 have a design flaw which leads to false MCE events - hence MCE is
393 disabled on all P5 processors, unless explicitly enabled with "mce"
394 as a boot argument. Similarly, if MCE is built in and creates a
395 problem on some new non-standard machine, you can boot with "nomce"
396 to disable it. MCE support simply ignores non-MCE processors like
397 the 386 and 486, so nearly everyone can say Y here.
399 config X86_MCE_NONFATAL
400 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
403 Enabling this feature starts a timer that triggers every 5 seconds which
404 will look at the machine check registers to see if anything happened.
405 Non-fatal problems automatically get corrected (but still logged).
406 Disable this if you don't want to see these messages.
407 Seeing the messages this option prints out may be indicative of dying
408 or out-of-spec (ie, overclocked) hardware.
409 This option only does something on certain CPUs.
410 (AMD Athlon/Duron and Intel Pentium 4)
412 config X86_MCE_P4THERMAL
413 bool "check for P4 thermal throttling interrupt."
414 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
416 Enabling this feature will cause a message to be printed when the P4
417 enters thermal throttling.
421 bool "Enable VM86 support" if EMBEDDED
423 This option is required by programs like DOSEMU to run 16-bit legacy
424 code on X86 processors. It also may be needed by software like
425 XFree86 to initialize some video cards via BIOS. Disabling this
426 option saves about 6k.
429 tristate "Toshiba Laptop support"
431 This adds a driver to safely access the System Management Mode of
432 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
433 not work on models with a Phoenix BIOS. The System Management Mode
434 is used to set the BIOS and power saving options on Toshiba portables.
436 For information on utilities to make use of this driver see the
437 Toshiba Linux utilities web site at:
438 <http://www.buzzard.org.uk/toshiba/>.
440 Say Y if you intend to run this kernel on a Toshiba portable.
444 tristate "Dell laptop support"
446 This adds a driver to safely access the System Management Mode
447 of the CPU on the Dell Inspiron 8000. The System Management Mode
448 is used to read cpu temperature and cooling fan status and to
449 control the fans on the I8K portables.
451 This driver has been tested only on the Inspiron 8000 but it may
452 also work with other Dell laptops. You can force loading on other
453 models by passing the parameter `force=1' to the module. Use at
456 For information on utilities to make use of this driver see the
457 I8K Linux utilities web site at:
458 <http://people.debian.org/~dz/i8k/>
460 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
463 config X86_REBOOTFIXUPS
464 bool "Enable X86 board specific fixups for reboot"
468 This enables chipset and/or board specific fixups to be done
469 in order to get reboot to work correctly. This is only needed on
470 some combinations of hardware and BIOS. The symptom, for which
471 this config is intended, is when reboot ends with a stalled/hung
474 Currently, the only fixup is for the Geode machines using
475 CS5530A and CS5536 chipsets.
477 Say Y if you want to enable the fixup. Currently, it's safe to
478 enable this option even if you don't need it.
482 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
485 If you say Y here, you will be able to update the microcode on
486 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
487 Pentium III, Pentium 4, Xeon etc. You will obviously need the
488 actual microcode binary data itself which is not shipped with the
491 For latest news and information on obtaining all the required
492 ingredients for this driver, check:
493 <http://www.urbanmyth.org/microcode/>.
495 To compile this driver as a module, choose M here: the
496 module will be called microcode.
498 config MICROCODE_OLD_INTERFACE
504 tristate "/dev/cpu/*/msr - Model-specific register support"
506 This device gives privileged processes access to the x86
507 Model-Specific Registers (MSRs). It is a character device with
508 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
509 MSR accesses are directed to a specific CPU on multi-processor
513 tristate "/dev/cpu/*/cpuid - CPU information support"
515 This device gives processes access to the x86 CPUID instruction to
516 be executed on a specific processor. It is a character device
517 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
520 source "drivers/firmware/Kconfig"
523 prompt "High Memory Support"
524 default HIGHMEM4G if !X86_NUMAQ
525 default HIGHMEM64G if X86_NUMAQ
529 depends on !X86_NUMAQ
531 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
532 However, the address space of 32-bit x86 processors is only 4
533 Gigabytes large. That means that, if you have a large amount of
534 physical memory, not all of it can be "permanently mapped" by the
535 kernel. The physical memory that's not permanently mapped is called
538 If you are compiling a kernel which will never run on a machine with
539 more than 1 Gigabyte total physical RAM, answer "off" here (default
540 choice and suitable for most users). This will result in a "3GB/1GB"
541 split: 3GB are mapped so that each process sees a 3GB virtual memory
542 space and the remaining part of the 4GB virtual memory space is used
543 by the kernel to permanently map as much physical memory as
546 If the machine has between 1 and 4 Gigabytes physical RAM, then
549 If more than 4 Gigabytes is used then answer "64GB" here. This
550 selection turns Intel PAE (Physical Address Extension) mode on.
551 PAE implements 3-level paging on IA32 processors. PAE is fully
552 supported by Linux, PAE mode is implemented on all recent Intel
553 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
554 then the kernel will not boot on CPUs that don't support PAE!
556 The actual amount of total physical memory will either be
557 auto detected or can be forced by using a kernel command line option
558 such as "mem=256M". (Try "man bootparam" or see the documentation of
559 your boot loader (lilo or loadlin) about how to pass options to the
560 kernel at boot time.)
562 If unsure, say "off".
566 depends on !X86_NUMAQ
568 Select this if you have a 32-bit processor and between 1 and 4
569 gigabytes of physical RAM.
573 depends on !M386 && !M486
576 Select this if you have a 32-bit processor and more than 4
577 gigabytes of physical RAM.
582 depends on EXPERIMENTAL
583 prompt "Memory split" if EMBEDDED
586 Select the desired split between kernel and user memory.
588 If the address range available to the kernel is less than the
589 physical memory installed, the remaining memory will be available
590 as "high memory". Accessing high memory is a little more costly
591 than low memory, as it needs to be mapped into the kernel first.
592 Note that increasing the kernel address space limits the range
593 available to user programs, making the address space there
594 tighter. Selecting anything other than the default 3G/1G split
595 will also likely make your kernel incompatible with binary-only
598 If you are not absolutely sure what you are doing, leave this
602 bool "3G/1G user/kernel split"
603 config VMSPLIT_3G_OPT
605 bool "3G/1G user/kernel split (for full 1G low memory)"
607 bool "2G/2G user/kernel split"
608 config VMSPLIT_2G_OPT
610 bool "2G/2G user/kernel split (for full 2G low memory)"
612 bool "1G/3G user/kernel split"
617 default 0xB0000000 if VMSPLIT_3G_OPT
618 default 0x80000000 if VMSPLIT_2G
619 default 0x78000000 if VMSPLIT_2G_OPT
620 default 0x40000000 if VMSPLIT_1G
625 depends on HIGHMEM64G || HIGHMEM4G
629 bool "PAE (Physical Address Extension) Support"
631 depends on !HIGHMEM4G
632 select RESOURCES_64BIT
634 PAE is required for NX support, and furthermore enables
635 larger swapspace support for non-overcommit purposes. It
636 has the cost of more pagetable lookup overhead, and also
637 consumes more pagetable space per process.
639 # Common NUMA Features
641 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
642 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL
644 default y if (X86_NUMAQ || X86_SUMMIT)
646 NUMA support for i386. This is currently highly experimental
647 and should be only used for kernel development. It might also
650 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
651 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
655 default "4" if X86_NUMAQ
657 depends on NEED_MULTIPLE_NODES
659 config HAVE_ARCH_BOOTMEM_NODE
664 config ARCH_HAVE_MEMORY_PRESENT
666 depends on DISCONTIGMEM
669 config NEED_NODE_MEMMAP_SIZE
671 depends on DISCONTIGMEM || SPARSEMEM
674 config HAVE_ARCH_ALLOC_REMAP
679 config ARCH_FLATMEM_ENABLE
681 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
683 config ARCH_DISCONTIGMEM_ENABLE
687 config ARCH_DISCONTIGMEM_DEFAULT
691 config ARCH_SPARSEMEM_ENABLE
693 depends on (NUMA || (X86_PC && EXPERIMENTAL))
694 select SPARSEMEM_STATIC
696 config ARCH_SELECT_MEMORY_MODEL
698 depends on ARCH_SPARSEMEM_ENABLE
700 config ARCH_POPULATES_NODE_MAP
706 bool "Allocate 3rd-level pagetables from highmem"
707 depends on HIGHMEM4G || HIGHMEM64G
709 The VM uses one page table entry for each page of physical memory.
710 For systems with a lot of RAM, this can be wasteful of precious
711 low memory. Setting this option will put user-space page table
712 entries in high memory.
714 config MATH_EMULATION
715 bool "Math emulation"
717 Linux can emulate a math coprocessor (used for floating point
718 operations) if you don't have one. 486DX and Pentium processors have
719 a math coprocessor built in, 486SX and 386 do not, unless you added
720 a 487DX or 387, respectively. (The messages during boot time can
721 give you some hints here ["man dmesg"].) Everyone needs either a
722 coprocessor or this emulation.
724 If you don't have a math coprocessor, you need to say Y here; if you
725 say Y here even though you have a coprocessor, the coprocessor will
726 be used nevertheless. (This behavior can be changed with the kernel
727 command line option "no387", which comes handy if your coprocessor
728 is broken. Try "man bootparam" or see the documentation of your boot
729 loader (lilo or loadlin) about how to pass options to the kernel at
730 boot time.) This means that it is a good idea to say Y here if you
731 intend to use this kernel on different machines.
733 More information about the internals of the Linux math coprocessor
734 emulation can be found in <file:arch/x86/math-emu/README>.
736 If you are not sure, say Y; apart from resulting in a 66 KB bigger
737 kernel, it won't hurt.
740 bool "MTRR (Memory Type Range Register) support"
742 On Intel P6 family processors (Pentium Pro, Pentium II and later)
743 the Memory Type Range Registers (MTRRs) may be used to control
744 processor access to memory ranges. This is most useful if you have
745 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
746 allows bus write transfers to be combined into a larger transfer
747 before bursting over the PCI/AGP bus. This can increase performance
748 of image write operations 2.5 times or more. Saying Y here creates a
749 /proc/mtrr file which may be used to manipulate your processor's
750 MTRRs. Typically the X server should use this.
752 This code has a reasonably generic interface so that similar
753 control registers on other processors can be easily supported
756 The Cyrix 6x86, 6x86MX and M II processors have Address Range
757 Registers (ARRs) which provide a similar functionality to MTRRs. For
758 these, the ARRs are used to emulate the MTRRs.
759 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
760 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
761 write-combining. All of these processors are supported by this code
762 and it makes sense to say Y here if you have one of them.
764 Saying Y here also fixes a problem with buggy SMP BIOSes which only
765 set the MTRRs for the boot CPU and not for the secondary CPUs. This
766 can lead to all sorts of problems, so it's good to say Y here.
768 You can safely say Y even if your machine doesn't have MTRRs, you'll
769 just add about 9 KB to your kernel.
771 See <file:Documentation/mtrr.txt> for more information.
774 bool "Boot from EFI support"
778 This enables the kernel to boot on EFI platforms using
779 system configuration information passed to it from the firmware.
780 This also enables the kernel to use any EFI runtime services that are
781 available (such as the EFI variable services).
783 This option is only useful on systems that have EFI firmware
784 and will result in a kernel image that is ~8k larger. In addition,
785 you must use the latest ELILO loader available at
786 <http://elilo.sourceforge.net> in order to take advantage of
787 kernel initialization using EFI information (neither GRUB nor LILO know
788 anything about EFI). However, even with this option, the resultant
789 kernel should continue to boot on existing non-EFI platforms.
792 bool "Enable kernel irq balancing"
793 depends on SMP && X86_IO_APIC
796 The default yes will allow the kernel to do irq load balancing.
797 Saying no will keep the kernel from doing irq load balancing.
799 # turning this on wastes a bunch of space.
800 # Summit needs it only when NUMA is on
803 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
807 bool "Enable seccomp to safely compute untrusted bytecode"
811 This kernel feature is useful for number crunching applications
812 that may need to compute untrusted bytecode during their
813 execution. By using pipes or other transports made available to
814 the process as file descriptors supporting the read/write
815 syscalls, it's possible to isolate those applications in
816 their own address space using seccomp. Once seccomp is
817 enabled via /proc/<pid>/seccomp, it cannot be disabled
818 and the task is only allowed to execute a few safe syscalls
819 defined by each seccomp mode.
821 If unsure, say Y. Only embedded should say N here.
823 source kernel/Kconfig.hz
826 bool "kexec system call"
828 kexec is a system call that implements the ability to shutdown your
829 current kernel, and to start another kernel. It is like a reboot
830 but it is independent of the system firmware. And like a reboot
831 you can start any kernel with it, not just Linux.
833 The name comes from the similarity to the exec system call.
835 It is an ongoing process to be certain the hardware in a machine
836 is properly shutdown, so do not be surprised if this code does not
837 initially work for you. It may help to enable device hotplugging
838 support. As of this writing the exact hardware interface is
839 strongly in flux, so no good recommendation can be made.
842 bool "kernel crash dumps (EXPERIMENTAL)"
843 depends on EXPERIMENTAL
846 Generate crash dump after being started by kexec.
847 This should be normally only set in special crash dump kernels
848 which are loaded in the main kernel with kexec-tools into
849 a specially reserved region and then later executed after
850 a crash by kdump/kexec. The crash dump kernel must be compiled
851 to a memory address not used by the main kernel or BIOS using
852 PHYSICAL_START, or it must be built as a relocatable image
853 (CONFIG_RELOCATABLE=y).
854 For more details see Documentation/kdump/kdump.txt
856 config PHYSICAL_START
857 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
858 default "0x1000000" if X86_NUMAQ
861 This gives the physical address where the kernel is loaded.
863 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
864 bzImage will decompress itself to above physical address and
865 run from there. Otherwise, bzImage will run from the address where
866 it has been loaded by the boot loader and will ignore above physical
869 In normal kdump cases one does not have to set/change this option
870 as now bzImage can be compiled as a completely relocatable image
871 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
872 address. This option is mainly useful for the folks who don't want
873 to use a bzImage for capturing the crash dump and want to use a
874 vmlinux instead. vmlinux is not relocatable hence a kernel needs
875 to be specifically compiled to run from a specific memory area
876 (normally a reserved region) and this option comes handy.
878 So if you are using bzImage for capturing the crash dump, leave
879 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
880 Otherwise if you plan to use vmlinux for capturing the crash dump
881 change this value to start of the reserved region (Typically 16MB
882 0x1000000). In other words, it can be set based on the "X" value as
883 specified in the "crashkernel=YM@XM" command line boot parameter
884 passed to the panic-ed kernel. Typically this parameter is set as
885 crashkernel=64M@16M. Please take a look at
886 Documentation/kdump/kdump.txt for more details about crash dumps.
888 Usage of bzImage for capturing the crash dump is recommended as
889 one does not have to build two kernels. Same kernel can be used
890 as production kernel and capture kernel. Above option should have
891 gone away after relocatable bzImage support is introduced. But it
892 is present because there are users out there who continue to use
893 vmlinux for dump capture. This option should go away down the
896 Don't change this unless you know what you are doing.
899 bool "Build a relocatable kernel (EXPERIMENTAL)"
900 depends on EXPERIMENTAL
902 This builds a kernel image that retains relocation information
903 so it can be loaded someplace besides the default 1MB.
904 The relocations tend to make the kernel binary about 10% larger,
905 but are discarded at runtime.
907 One use is for the kexec on panic case where the recovery kernel
908 must live at a different physical address than the primary
911 config PHYSICAL_ALIGN
912 hex "Alignment value to which kernel should be aligned"
914 range 0x2000 0x400000
916 This value puts the alignment restrictions on physical address
917 where kernel is loaded and run from. Kernel is compiled for an
918 address which meets above alignment restriction.
920 If bootloader loads the kernel at a non-aligned address and
921 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
922 address aligned to above value and run from there.
924 If bootloader loads the kernel at a non-aligned address and
925 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
926 load address and decompress itself to the address it has been
927 compiled for and run from there. The address for which kernel is
928 compiled already meets above alignment restrictions. Hence the
929 end result is that kernel runs from a physical address meeting
930 above alignment restrictions.
932 Don't change this unless you know what you are doing.
935 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
936 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
938 Say Y here to experiment with turning CPUs off and on, and to
939 enable suspend on SMP systems. CPUs can be controlled through
940 /sys/devices/system/cpu.
943 bool "Compat VDSO support"
946 Map the VDSO to the predictable old-style address too.
948 Say N here if you are running a sufficiently recent glibc
949 version (2.3.3 or later), to remove the high-mapped
950 VDSO mapping and to exclusively use the randomized VDSO.
956 config ARCH_ENABLE_MEMORY_HOTPLUG
960 menu "Power management options (ACPI, APM)"
961 depends on !X86_VOYAGER
963 source kernel/power/Kconfig
965 source "drivers/acpi/Kconfig"
968 tristate "APM (Advanced Power Management) BIOS support"
969 depends on PM_SLEEP && !X86_VISWS
971 APM is a BIOS specification for saving power using several different
972 techniques. This is mostly useful for battery powered laptops with
973 APM compliant BIOSes. If you say Y here, the system time will be
974 reset after a RESUME operation, the /proc/apm device will provide
975 battery status information, and user-space programs will receive
976 notification of APM "events" (e.g. battery status change).
978 If you select "Y" here, you can disable actual use of the APM
979 BIOS by passing the "apm=off" option to the kernel at boot time.
981 Note that the APM support is almost completely disabled for
982 machines with more than one CPU.
984 In order to use APM, you will need supporting software. For location
985 and more information, read <file:Documentation/pm.txt> and the
986 Battery Powered Linux mini-HOWTO, available from
987 <http://www.tldp.org/docs.html#howto>.
989 This driver does not spin down disk drives (see the hdparm(8)
990 manpage ("man 8 hdparm") for that), and it doesn't turn off
991 VESA-compliant "green" monitors.
993 This driver does not support the TI 4000M TravelMate and the ACER
994 486/DX4/75 because they don't have compliant BIOSes. Many "green"
995 desktop machines also don't have compliant BIOSes, and this driver
996 may cause those machines to panic during the boot phase.
998 Generally, if you don't have a battery in your machine, there isn't
999 much point in using this driver and you should say N. If you get
1000 random kernel OOPSes or reboots that don't seem to be related to
1001 anything, try disabling/enabling this option (or disabling/enabling
1004 Some other things you should try when experiencing seemingly random,
1007 1) make sure that you have enough swap space and that it is
1009 2) pass the "no-hlt" option to the kernel
1010 3) switch on floating point emulation in the kernel and pass
1011 the "no387" option to the kernel
1012 4) pass the "floppy=nodma" option to the kernel
1013 5) pass the "mem=4M" option to the kernel (thereby disabling
1014 all but the first 4 MB of RAM)
1015 6) make sure that the CPU is not over clocked.
1016 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1017 8) disable the cache from your BIOS settings
1018 9) install a fan for the video card or exchange video RAM
1019 10) install a better fan for the CPU
1020 11) exchange RAM chips
1021 12) exchange the motherboard.
1023 To compile this driver as a module, choose M here: the
1024 module will be called apm.
1028 config APM_IGNORE_USER_SUSPEND
1029 bool "Ignore USER SUSPEND"
1031 This option will ignore USER SUSPEND requests. On machines with a
1032 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1033 series notebooks, it is necessary to say Y because of a BIOS bug.
1035 config APM_DO_ENABLE
1036 bool "Enable PM at boot time"
1038 Enable APM features at boot time. From page 36 of the APM BIOS
1039 specification: "When disabled, the APM BIOS does not automatically
1040 power manage devices, enter the Standby State, enter the Suspend
1041 State, or take power saving steps in response to CPU Idle calls."
1042 This driver will make CPU Idle calls when Linux is idle (unless this
1043 feature is turned off -- see "Do CPU IDLE calls", below). This
1044 should always save battery power, but more complicated APM features
1045 will be dependent on your BIOS implementation. You may need to turn
1046 this option off if your computer hangs at boot time when using APM
1047 support, or if it beeps continuously instead of suspending. Turn
1048 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1049 T400CDT. This is off by default since most machines do fine without
1053 bool "Make CPU Idle calls when idle"
1055 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1056 On some machines, this can activate improved power savings, such as
1057 a slowed CPU clock rate, when the machine is idle. These idle calls
1058 are made after the idle loop has run for some length of time (e.g.,
1059 333 mS). On some machines, this will cause a hang at boot time or
1060 whenever the CPU becomes idle. (On machines with more than one CPU,
1061 this option does nothing.)
1063 config APM_DISPLAY_BLANK
1064 bool "Enable console blanking using APM"
1066 Enable console blanking using the APM. Some laptops can use this to
1067 turn off the LCD backlight when the screen blanker of the Linux
1068 virtual console blanks the screen. Note that this is only used by
1069 the virtual console screen blanker, and won't turn off the backlight
1070 when using the X Window system. This also doesn't have anything to
1071 do with your VESA-compliant power-saving monitor. Further, this
1072 option doesn't work for all laptops -- it might not turn off your
1073 backlight at all, or it might print a lot of errors to the console,
1074 especially if you are using gpm.
1076 config APM_ALLOW_INTS
1077 bool "Allow interrupts during APM BIOS calls"
1079 Normally we disable external interrupts while we are making calls to
1080 the APM BIOS as a measure to lessen the effects of a badly behaving
1081 BIOS implementation. The BIOS should reenable interrupts if it
1082 needs to. Unfortunately, some BIOSes do not -- especially those in
1083 many of the newer IBM Thinkpads. If you experience hangs when you
1084 suspend, try setting this to Y. Otherwise, say N.
1086 config APM_REAL_MODE_POWER_OFF
1087 bool "Use real mode APM BIOS call to power off"
1089 Use real mode APM BIOS calls to switch off the computer. This is
1090 a work-around for a number of buggy BIOSes. Switch this option on if
1091 your computer crashes instead of powering off properly.
1095 source "arch/x86/kernel/cpu/cpufreq/Kconfig_32"
1097 source "drivers/cpuidle/Kconfig"
1101 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1104 bool "PCI support" if !X86_VISWS
1105 depends on !X86_VOYAGER
1106 default y if X86_VISWS
1107 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1109 Find out whether you have a PCI motherboard. PCI is the name of a
1110 bus system, i.e. the way the CPU talks to the other stuff inside
1111 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1112 VESA. If you have PCI, say Y, otherwise N.
1114 The PCI-HOWTO, available from
1115 <http://www.tldp.org/docs.html#howto>, contains valuable
1116 information about which PCI hardware does work under Linux and which
1120 prompt "PCI access mode"
1121 depends on PCI && !X86_VISWS
1124 On PCI systems, the BIOS can be used to detect the PCI devices and
1125 determine their configuration. However, some old PCI motherboards
1126 have BIOS bugs and may crash if this is done. Also, some embedded
1127 PCI-based systems don't have any BIOS at all. Linux can also try to
1128 detect the PCI hardware directly without using the BIOS.
1130 With this option, you can specify how Linux should detect the
1131 PCI devices. If you choose "BIOS", the BIOS will be used,
1132 if you choose "Direct", the BIOS won't be used, and if you
1133 choose "MMConfig", then PCI Express MMCONFIG will be used.
1134 If you choose "Any", the kernel will try MMCONFIG, then the
1135 direct access method and falls back to the BIOS if that doesn't
1136 work. If unsure, go with the default, which is "Any".
1141 config PCI_GOMMCONFIG
1154 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1159 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1164 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1172 source "drivers/pci/pcie/Kconfig"
1174 source "drivers/pci/Kconfig"
1182 depends on !(X86_VOYAGER || X86_VISWS)
1184 Find out whether you have ISA slots on your motherboard. ISA is the
1185 name of a bus system, i.e. the way the CPU talks to the other stuff
1186 inside your box. Other bus systems are PCI, EISA, MicroChannel
1187 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1188 newer boards don't support it. If you have ISA, say Y, otherwise N.
1194 The Extended Industry Standard Architecture (EISA) bus was
1195 developed as an open alternative to the IBM MicroChannel bus.
1197 The EISA bus provided some of the features of the IBM MicroChannel
1198 bus while maintaining backward compatibility with cards made for
1199 the older ISA bus. The EISA bus saw limited use between 1988 and
1200 1995 when it was made obsolete by the PCI bus.
1202 Say Y here if you are building a kernel for an EISA-based machine.
1206 source "drivers/eisa/Kconfig"
1209 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1210 default y if X86_VOYAGER
1212 MicroChannel Architecture is found in some IBM PS/2 machines and
1213 laptops. It is a bus system similar to PCI or ISA. See
1214 <file:Documentation/mca.txt> (and especially the web page given
1215 there) before attempting to build an MCA bus kernel.
1217 source "drivers/mca/Kconfig"
1220 tristate "NatSemi SCx200 support"
1221 depends on !X86_VOYAGER
1223 This provides basic support for National Semiconductor's
1224 (now AMD's) Geode processors. The driver probes for the
1225 PCI-IDs of several on-chip devices, so its a good dependency
1226 for other scx200_* drivers.
1228 If compiled as a module, the driver is named scx200.
1230 config SCx200HR_TIMER
1231 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1232 depends on SCx200 && GENERIC_TIME
1235 This driver provides a clocksource built upon the on-chip
1236 27MHz high-resolution timer. Its also a workaround for
1237 NSC Geode SC-1100's buggy TSC, which loses time when the
1238 processor goes idle (as is done by the scheduler). The
1239 other workaround is idle=poll boot option.
1241 config GEODE_MFGPT_TIMER
1242 bool "Geode Multi-Function General Purpose Timer (MFGPT) events"
1243 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1246 This driver provides a clock event source based on the MFGPT
1247 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1248 MFGPTs have a better resolution and max interval than the
1249 generic PIT, and are suitable for use as high-res timers.
1253 depends on AGP_AMD64
1255 source "drivers/pcmcia/Kconfig"
1257 source "drivers/pci/hotplug/Kconfig"
1261 menu "Executable file formats"
1263 source "fs/Kconfig.binfmt"
1267 source "net/Kconfig"
1269 source "drivers/Kconfig"
1273 source "kernel/Kconfig.instrumentation"
1275 source "arch/x86/Kconfig.debug"
1277 source "security/Kconfig"
1279 source "crypto/Kconfig"
1281 source "lib/Kconfig"
1284 # Use the generic interrupt handling code in kernel/irq/:
1286 config GENERIC_HARDIRQS
1290 config GENERIC_IRQ_PROBE
1294 config GENERIC_PENDING_IRQ
1296 depends on GENERIC_HARDIRQS && SMP
1301 depends on SMP && !X86_VOYAGER
1306 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1309 config X86_BIOS_REBOOT
1311 depends on !(X86_VISWS || X86_VOYAGER)
1314 config X86_TRAMPOLINE
1316 depends on X86_SMP || (X86_VOYAGER && SMP)
projects / mirror_ubuntu-bionic-kernel.git / blob