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.
150 Voyager is an MCA-based 32-way capable SMP architecture proprietary
151 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
155 If you do not specifically know you have a Voyager based machine,
156 say N here, otherwise the kernel you build will not be bootable.
159 bool "NUMAQ (IBM/Sequent)"
163 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
164 multiquad box. This changes the way that processors are bootstrapped,
165 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
166 You will need a new lynxer.elf file to flash your firmware with - send
167 email to <Martin.Bligh@us.ibm.com>.
170 bool "Summit/EXA (IBM x440)"
173 This option is needed for IBM systems that use the Summit/EXA chipset.
174 In particular, it is needed for the x440.
176 If you don't have one of these computers, you should say N here.
177 If you want to build a NUMA kernel, you must select ACPI.
180 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
183 This option is needed for the systems that have more than 8 CPUs
184 and if the system is not of any sub-arch type above.
186 If you don't have such a system, you should say N here.
189 bool "SGI 320/540 (Visual Workstation)"
191 The SGI Visual Workstation series is an IA32-based workstation
192 based on SGI systems chips with some legacy PC hardware attached.
194 Say Y here to create a kernel to run on the SGI 320 or 540.
196 A kernel compiled for the Visual Workstation will not run on PCs
197 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
199 config X86_GENERICARCH
200 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
202 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
203 It is intended for a generic binary kernel.
204 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
207 bool "Support for Unisys ES7000 IA32 series"
210 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
211 supposed to run on an IA32-based Unisys ES7000 system.
212 Only choose this option if you have such a system, otherwise you
217 config SCHED_NO_NO_OMIT_FRAME_POINTER
218 bool "Single-depth WCHAN output"
221 Calculate simpler /proc/<PID>/wchan values. If this option
222 is disabled then wchan values will recurse back to the
223 caller function. This provides more accurate wchan values,
224 at the expense of slightly more scheduling overhead.
226 If in doubt, say "Y".
229 bool "Paravirtualization support (EXPERIMENTAL)"
230 depends on EXPERIMENTAL
231 depends on !(X86_VISWS || X86_VOYAGER)
233 Paravirtualization is a way of running multiple instances of
234 Linux on the same machine, under a hypervisor. This option
235 changes the kernel so it can modify itself when it is run
236 under a hypervisor, improving performance significantly.
237 However, when run without a hypervisor the kernel is
238 theoretically slower. If in doubt, say N.
240 source "arch/x86/xen/Kconfig"
243 bool "VMI Paravirt-ops support"
246 VMI provides a paravirtualized interface to the VMware ESX server
247 (it could be used by other hypervisors in theory too, but is not
248 at the moment), by linking the kernel to a GPL-ed ROM module
249 provided by the hypervisor.
254 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
257 config HAVE_ARCH_PARSE_SRAT
262 config X86_SUMMIT_NUMA
265 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
267 config X86_CYCLONE_TIMER
270 depends on X86_SUMMIT || X86_GENERICARCH
272 config ES7000_CLUSTERED_APIC
275 depends on SMP && X86_ES7000 && MPENTIUMIII
277 source "arch/i386/Kconfig.cpu"
280 bool "HPET Timer Support"
282 This enables the use of the HPET for the kernel's internal timer.
283 HPET is the next generation timer replacing legacy 8254s.
284 You can safely choose Y here. However, HPET will only be
285 activated if the platform and the BIOS support this feature.
286 Otherwise the 8254 will be used for timing services.
288 Choose N to continue using the legacy 8254 timer.
290 config HPET_EMULATE_RTC
292 depends on HPET_TIMER && RTC=y
296 int "Maximum number of CPUs (2-255)"
299 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
302 This allows you to specify the maximum number of CPUs which this
303 kernel will support. The maximum supported value is 255 and the
304 minimum value which makes sense is 2.
306 This is purely to save memory - each supported CPU adds
307 approximately eight kilobytes to the kernel image.
310 bool "SMT (Hyperthreading) scheduler support"
313 SMT scheduler support improves the CPU scheduler's decision making
314 when dealing with Intel Pentium 4 chips with HyperThreading at a
315 cost of slightly increased overhead in some places. If unsure say
319 bool "Multi-core scheduler support"
323 Multi-core scheduler support improves the CPU scheduler's decision
324 making when dealing with multi-core CPU chips at a cost of slightly
325 increased overhead in some places. If unsure say N here.
327 source "kernel/Kconfig.preempt"
330 bool "Local APIC support on uniprocessors"
331 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
333 A local APIC (Advanced Programmable Interrupt Controller) is an
334 integrated interrupt controller in the CPU. If you have a single-CPU
335 system which has a processor with a local APIC, you can say Y here to
336 enable and use it. If you say Y here even though your machine doesn't
337 have a local APIC, then the kernel will still run with no slowdown at
338 all. The local APIC supports CPU-generated self-interrupts (timer,
339 performance counters), and the NMI watchdog which detects hard
343 bool "IO-APIC support on uniprocessors"
344 depends on X86_UP_APIC
346 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
347 SMP-capable replacement for PC-style interrupt controllers. Most
348 SMP systems and many recent uniprocessor systems have one.
350 If you have a single-CPU system with an IO-APIC, you can say Y here
351 to use it. If you say Y here even though your machine doesn't have
352 an IO-APIC, then the kernel will still run with no slowdown at all.
354 config X86_LOCAL_APIC
356 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
361 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
364 config X86_VISWS_APIC
370 bool "Machine Check Exception"
371 depends on !X86_VOYAGER
373 Machine Check Exception support allows the processor to notify the
374 kernel if it detects a problem (e.g. overheating, component failure).
375 The action the kernel takes depends on the severity of the problem,
376 ranging from a warning message on the console, to halting the machine.
377 Your processor must be a Pentium or newer to support this - check the
378 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
379 have a design flaw which leads to false MCE events - hence MCE is
380 disabled on all P5 processors, unless explicitly enabled with "mce"
381 as a boot argument. Similarly, if MCE is built in and creates a
382 problem on some new non-standard machine, you can boot with "nomce"
383 to disable it. MCE support simply ignores non-MCE processors like
384 the 386 and 486, so nearly everyone can say Y here.
386 config X86_MCE_NONFATAL
387 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
390 Enabling this feature starts a timer that triggers every 5 seconds which
391 will look at the machine check registers to see if anything happened.
392 Non-fatal problems automatically get corrected (but still logged).
393 Disable this if you don't want to see these messages.
394 Seeing the messages this option prints out may be indicative of dying hardware,
395 or out-of-spec (ie, overclocked) hardware.
396 This option only does something on certain CPUs.
397 (AMD Athlon/Duron and Intel Pentium 4)
399 config X86_MCE_P4THERMAL
400 bool "check for P4 thermal throttling interrupt."
401 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
403 Enabling this feature will cause a message to be printed when the P4
404 enters thermal throttling.
408 bool "Enable VM86 support" if EMBEDDED
410 This option is required by programs like DOSEMU to run 16-bit legacy
411 code on X86 processors. It also may be needed by software like
412 XFree86 to initialize some video cards via BIOS. Disabling this
413 option saves about 6k.
416 tristate "Toshiba Laptop support"
418 This adds a driver to safely access the System Management Mode of
419 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
420 not work on models with a Phoenix BIOS. The System Management Mode
421 is used to set the BIOS and power saving options on Toshiba portables.
423 For information on utilities to make use of this driver see the
424 Toshiba Linux utilities web site at:
425 <http://www.buzzard.org.uk/toshiba/>.
427 Say Y if you intend to run this kernel on a Toshiba portable.
431 tristate "Dell laptop support"
433 This adds a driver to safely access the System Management Mode
434 of the CPU on the Dell Inspiron 8000. The System Management Mode
435 is used to read cpu temperature and cooling fan status and to
436 control the fans on the I8K portables.
438 This driver has been tested only on the Inspiron 8000 but it may
439 also work with other Dell laptops. You can force loading on other
440 models by passing the parameter `force=1' to the module. Use at
443 For information on utilities to make use of this driver see the
444 I8K Linux utilities web site at:
445 <http://people.debian.org/~dz/i8k/>
447 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
450 config X86_REBOOTFIXUPS
451 bool "Enable X86 board specific fixups for reboot"
455 This enables chipset and/or board specific fixups to be done
456 in order to get reboot to work correctly. This is only needed on
457 some combinations of hardware and BIOS. The symptom, for which
458 this config is intended, is when reboot ends with a stalled/hung
461 Currently, the only fixup is for the Geode machines using
462 CS5530A and CS5536 chipsets.
464 Say Y if you want to enable the fixup. Currently, it's safe to
465 enable this option even if you don't need it.
469 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
472 If you say Y here, you will be able to update the microcode on
473 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
474 Pentium III, Pentium 4, Xeon etc. You will obviously need the
475 actual microcode binary data itself which is not shipped with the
478 For latest news and information on obtaining all the required
479 ingredients for this driver, check:
480 <http://www.urbanmyth.org/microcode/>.
482 To compile this driver as a module, choose M here: the
483 module will be called microcode.
485 config MICROCODE_OLD_INTERFACE
491 tristate "/dev/cpu/*/msr - Model-specific register support"
493 This device gives privileged processes access to the x86
494 Model-Specific Registers (MSRs). It is a character device with
495 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
496 MSR accesses are directed to a specific CPU on multi-processor
500 tristate "/dev/cpu/*/cpuid - CPU information support"
502 This device gives processes access to the x86 CPUID instruction to
503 be executed on a specific processor. It is a character device
504 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
507 source "drivers/firmware/Kconfig"
510 prompt "High Memory Support"
511 default HIGHMEM4G if !X86_NUMAQ
512 default HIGHMEM64G if X86_NUMAQ
516 depends on !X86_NUMAQ
518 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
519 However, the address space of 32-bit x86 processors is only 4
520 Gigabytes large. That means that, if you have a large amount of
521 physical memory, not all of it can be "permanently mapped" by the
522 kernel. The physical memory that's not permanently mapped is called
525 If you are compiling a kernel which will never run on a machine with
526 more than 1 Gigabyte total physical RAM, answer "off" here (default
527 choice and suitable for most users). This will result in a "3GB/1GB"
528 split: 3GB are mapped so that each process sees a 3GB virtual memory
529 space and the remaining part of the 4GB virtual memory space is used
530 by the kernel to permanently map as much physical memory as
533 If the machine has between 1 and 4 Gigabytes physical RAM, then
536 If more than 4 Gigabytes is used then answer "64GB" here. This
537 selection turns Intel PAE (Physical Address Extension) mode on.
538 PAE implements 3-level paging on IA32 processors. PAE is fully
539 supported by Linux, PAE mode is implemented on all recent Intel
540 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
541 then the kernel will not boot on CPUs that don't support PAE!
543 The actual amount of total physical memory will either be
544 auto detected or can be forced by using a kernel command line option
545 such as "mem=256M". (Try "man bootparam" or see the documentation of
546 your boot loader (lilo or loadlin) about how to pass options to the
547 kernel at boot time.)
549 If unsure, say "off".
553 depends on !X86_NUMAQ
555 Select this if you have a 32-bit processor and between 1 and 4
556 gigabytes of physical RAM.
560 depends on !M386 && !M486
563 Select this if you have a 32-bit processor and more than 4
564 gigabytes of physical RAM.
569 depends on EXPERIMENTAL
570 prompt "Memory split" if EMBEDDED
573 Select the desired split between kernel and user memory.
575 If the address range available to the kernel is less than the
576 physical memory installed, the remaining memory will be available
577 as "high memory". Accessing high memory is a little more costly
578 than low memory, as it needs to be mapped into the kernel first.
579 Note that increasing the kernel address space limits the range
580 available to user programs, making the address space there
581 tighter. Selecting anything other than the default 3G/1G split
582 will also likely make your kernel incompatible with binary-only
585 If you are not absolutely sure what you are doing, leave this
589 bool "3G/1G user/kernel split"
590 config VMSPLIT_3G_OPT
592 bool "3G/1G user/kernel split (for full 1G low memory)"
594 bool "2G/2G user/kernel split"
595 config VMSPLIT_2G_OPT
597 bool "2G/2G user/kernel split (for full 2G low memory)"
599 bool "1G/3G user/kernel split"
604 default 0xB0000000 if VMSPLIT_3G_OPT
605 default 0x80000000 if VMSPLIT_2G
606 default 0x78000000 if VMSPLIT_2G_OPT
607 default 0x40000000 if VMSPLIT_1G
612 depends on HIGHMEM64G || HIGHMEM4G
616 bool "PAE (Physical Address Extension) Support"
618 depends on !HIGHMEM4G
619 select RESOURCES_64BIT
621 PAE is required for NX support, and furthermore enables
622 larger swapspace support for non-overcommit purposes. It
623 has the cost of more pagetable lookup overhead, and also
624 consumes more pagetable space per process.
626 # Common NUMA Features
628 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
629 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL
631 default y if (X86_NUMAQ || X86_SUMMIT)
633 NUMA support for i386. This is currently high experimental
634 and should be only used for kernel development. It might also
637 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
638 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
642 default "4" if X86_NUMAQ
644 depends on NEED_MULTIPLE_NODES
646 config HAVE_ARCH_BOOTMEM_NODE
651 config ARCH_HAVE_MEMORY_PRESENT
653 depends on DISCONTIGMEM
656 config NEED_NODE_MEMMAP_SIZE
658 depends on DISCONTIGMEM || SPARSEMEM
661 config HAVE_ARCH_ALLOC_REMAP
666 config ARCH_FLATMEM_ENABLE
668 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
670 config ARCH_DISCONTIGMEM_ENABLE
674 config ARCH_DISCONTIGMEM_DEFAULT
678 config ARCH_SPARSEMEM_ENABLE
680 depends on (NUMA || (X86_PC && EXPERIMENTAL))
681 select SPARSEMEM_STATIC
683 config ARCH_SELECT_MEMORY_MODEL
685 depends on ARCH_SPARSEMEM_ENABLE
687 config ARCH_POPULATES_NODE_MAP
693 bool "Allocate 3rd-level pagetables from highmem"
694 depends on HIGHMEM4G || HIGHMEM64G
696 The VM uses one page table entry for each page of physical memory.
697 For systems with a lot of RAM, this can be wasteful of precious
698 low memory. Setting this option will put user-space page table
699 entries in high memory.
701 config MATH_EMULATION
702 bool "Math emulation"
704 Linux can emulate a math coprocessor (used for floating point
705 operations) if you don't have one. 486DX and Pentium processors have
706 a math coprocessor built in, 486SX and 386 do not, unless you added
707 a 487DX or 387, respectively. (The messages during boot time can
708 give you some hints here ["man dmesg"].) Everyone needs either a
709 coprocessor or this emulation.
711 If you don't have a math coprocessor, you need to say Y here; if you
712 say Y here even though you have a coprocessor, the coprocessor will
713 be used nevertheless. (This behavior can be changed with the kernel
714 command line option "no387", which comes handy if your coprocessor
715 is broken. Try "man bootparam" or see the documentation of your boot
716 loader (lilo or loadlin) about how to pass options to the kernel at
717 boot time.) This means that it is a good idea to say Y here if you
718 intend to use this kernel on different machines.
720 More information about the internals of the Linux math coprocessor
721 emulation can be found in <file:arch/x86/math-emu/README>.
723 If you are not sure, say Y; apart from resulting in a 66 KB bigger
724 kernel, it won't hurt.
727 bool "MTRR (Memory Type Range Register) support"
729 On Intel P6 family processors (Pentium Pro, Pentium II and later)
730 the Memory Type Range Registers (MTRRs) may be used to control
731 processor access to memory ranges. This is most useful if you have
732 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
733 allows bus write transfers to be combined into a larger transfer
734 before bursting over the PCI/AGP bus. This can increase performance
735 of image write operations 2.5 times or more. Saying Y here creates a
736 /proc/mtrr file which may be used to manipulate your processor's
737 MTRRs. Typically the X server should use this.
739 This code has a reasonably generic interface so that similar
740 control registers on other processors can be easily supported
743 The Cyrix 6x86, 6x86MX and M II processors have Address Range
744 Registers (ARRs) which provide a similar functionality to MTRRs. For
745 these, the ARRs are used to emulate the MTRRs.
746 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
747 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
748 write-combining. All of these processors are supported by this code
749 and it makes sense to say Y here if you have one of them.
751 Saying Y here also fixes a problem with buggy SMP BIOSes which only
752 set the MTRRs for the boot CPU and not for the secondary CPUs. This
753 can lead to all sorts of problems, so it's good to say Y here.
755 You can safely say Y even if your machine doesn't have MTRRs, you'll
756 just add about 9 KB to your kernel.
758 See <file:Documentation/mtrr.txt> for more information.
761 bool "Boot from EFI support"
765 This enables the kernel to boot on EFI platforms using
766 system configuration information passed to it from the firmware.
767 This also enables the kernel to use any EFI runtime services that are
768 available (such as the EFI variable services).
770 This option is only useful on systems that have EFI firmware
771 and will result in a kernel image that is ~8k larger. In addition,
772 you must use the latest ELILO loader available at
773 <http://elilo.sourceforge.net> in order to take advantage of
774 kernel initialization using EFI information (neither GRUB nor LILO know
775 anything about EFI). However, even with this option, the resultant
776 kernel should continue to boot on existing non-EFI platforms.
779 bool "Enable kernel irq balancing"
780 depends on SMP && X86_IO_APIC
783 The default yes will allow the kernel to do irq load balancing.
784 Saying no will keep the kernel from doing irq load balancing.
786 # turning this on wastes a bunch of space.
787 # Summit needs it only when NUMA is on
790 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
794 bool "Enable seccomp to safely compute untrusted bytecode"
798 This kernel feature is useful for number crunching applications
799 that may need to compute untrusted bytecode during their
800 execution. By using pipes or other transports made available to
801 the process as file descriptors supporting the read/write
802 syscalls, it's possible to isolate those applications in
803 their own address space using seccomp. Once seccomp is
804 enabled via /proc/<pid>/seccomp, it cannot be disabled
805 and the task is only allowed to execute a few safe syscalls
806 defined by each seccomp mode.
808 If unsure, say Y. Only embedded should say N here.
810 source kernel/Kconfig.hz
813 bool "kexec system call"
815 kexec is a system call that implements the ability to shutdown your
816 current kernel, and to start another kernel. It is like a reboot
817 but it is independent of the system firmware. And like a reboot
818 you can start any kernel with it, not just Linux.
820 The name comes from the similarity to the exec system call.
822 It is an ongoing process to be certain the hardware in a machine
823 is properly shutdown, so do not be surprised if this code does not
824 initially work for you. It may help to enable device hotplugging
825 support. As of this writing the exact hardware interface is
826 strongly in flux, so no good recommendation can be made.
829 bool "kernel crash dumps (EXPERIMENTAL)"
830 depends on EXPERIMENTAL
833 Generate crash dump after being started by kexec.
834 This should be normally only set in special crash dump kernels
835 which are loaded in the main kernel with kexec-tools into
836 a specially reserved region and then later executed after
837 a crash by kdump/kexec. The crash dump kernel must be compiled
838 to a memory address not used by the main kernel or BIOS using
840 For more details see Documentation/kdump/kdump.txt
842 config PHYSICAL_START
843 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
844 default "0x1000000" if X86_NUMAQ
847 This gives the physical address where the kernel is loaded.
849 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
850 bzImage will decompress itself to above physical address and
851 run from there. Otherwise, bzImage will run from the address where
852 it has been loaded by the boot loader and will ignore above physical
855 In normal kdump cases one does not have to set/change this option
856 as now bzImage can be compiled as a completely relocatable image
857 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
858 address. This option is mainly useful for the folks who don't want
859 to use a bzImage for capturing the crash dump and want to use a
860 vmlinux instead. vmlinux is not relocatable hence a kernel needs
861 to be specifically compiled to run from a specific memory area
862 (normally a reserved region) and this option comes handy.
864 So if you are using bzImage for capturing the crash dump, leave
865 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
866 Otherwise if you plan to use vmlinux for capturing the crash dump
867 change this value to start of the reserved region (Typically 16MB
868 0x1000000). In other words, it can be set based on the "X" value as
869 specified in the "crashkernel=YM@XM" command line boot parameter
870 passed to the panic-ed kernel. Typically this parameter is set as
871 crashkernel=64M@16M. Please take a look at
872 Documentation/kdump/kdump.txt for more details about crash dumps.
874 Usage of bzImage for capturing the crash dump is recommended as
875 one does not have to build two kernels. Same kernel can be used
876 as production kernel and capture kernel. Above option should have
877 gone away after relocatable bzImage support is introduced. But it
878 is present because there are users out there who continue to use
879 vmlinux for dump capture. This option should go away down the
882 Don't change this unless you know what you are doing.
885 bool "Build a relocatable kernel(EXPERIMENTAL)"
886 depends on EXPERIMENTAL
888 This builds a kernel image that retains relocation information
889 so it can be loaded someplace besides the default 1MB.
890 The relocations tend to make the kernel binary about 10% larger,
891 but are discarded at runtime.
893 One use is for the kexec on panic case where the recovery kernel
894 must live at a different physical address than the primary
897 config PHYSICAL_ALIGN
898 hex "Alignment value to which kernel should be aligned"
900 range 0x2000 0x400000
902 This value puts the alignment restrictions on physical address
903 where kernel is loaded and run from. Kernel is compiled for an
904 address which meets above alignment restriction.
906 If bootloader loads the kernel at a non-aligned address and
907 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
908 address aligned to above value and run from there.
910 If bootloader loads the kernel at a non-aligned address and
911 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
912 load address and decompress itself to the address it has been
913 compiled for and run from there. The address for which kernel is
914 compiled already meets above alignment restrictions. Hence the
915 end result is that kernel runs from a physical address meeting
916 above alignment restrictions.
918 Don't change this unless you know what you are doing.
921 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
922 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
924 Say Y here to experiment with turning CPUs off and on, and to
925 enable suspend on SMP systems. CPUs can be controlled through
926 /sys/devices/system/cpu.
929 bool "Compat VDSO support"
932 Map the VDSO to the predictable old-style address too.
934 Say N here if you are running a sufficiently recent glibc
935 version (2.3.3 or later), to remove the high-mapped
936 VDSO mapping and to exclusively use the randomized VDSO.
942 config ARCH_ENABLE_MEMORY_HOTPLUG
946 menu "Power management options (ACPI, APM)"
947 depends on !X86_VOYAGER
949 source kernel/power/Kconfig
951 source "drivers/acpi/Kconfig"
954 tristate "APM (Advanced Power Management) BIOS support"
955 depends on PM_SLEEP && !X86_VISWS
957 APM is a BIOS specification for saving power using several different
958 techniques. This is mostly useful for battery powered laptops with
959 APM compliant BIOSes. If you say Y here, the system time will be
960 reset after a RESUME operation, the /proc/apm device will provide
961 battery status information, and user-space programs will receive
962 notification of APM "events" (e.g. battery status change).
964 If you select "Y" here, you can disable actual use of the APM
965 BIOS by passing the "apm=off" option to the kernel at boot time.
967 Note that the APM support is almost completely disabled for
968 machines with more than one CPU.
970 In order to use APM, you will need supporting software. For location
971 and more information, read <file:Documentation/pm.txt> and the
972 Battery Powered Linux mini-HOWTO, available from
973 <http://www.tldp.org/docs.html#howto>.
975 This driver does not spin down disk drives (see the hdparm(8)
976 manpage ("man 8 hdparm") for that), and it doesn't turn off
977 VESA-compliant "green" monitors.
979 This driver does not support the TI 4000M TravelMate and the ACER
980 486/DX4/75 because they don't have compliant BIOSes. Many "green"
981 desktop machines also don't have compliant BIOSes, and this driver
982 may cause those machines to panic during the boot phase.
984 Generally, if you don't have a battery in your machine, there isn't
985 much point in using this driver and you should say N. If you get
986 random kernel OOPSes or reboots that don't seem to be related to
987 anything, try disabling/enabling this option (or disabling/enabling
990 Some other things you should try when experiencing seemingly random,
993 1) make sure that you have enough swap space and that it is
995 2) pass the "no-hlt" option to the kernel
996 3) switch on floating point emulation in the kernel and pass
997 the "no387" option to the kernel
998 4) pass the "floppy=nodma" option to the kernel
999 5) pass the "mem=4M" option to the kernel (thereby disabling
1000 all but the first 4 MB of RAM)
1001 6) make sure that the CPU is not over clocked.
1002 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1003 8) disable the cache from your BIOS settings
1004 9) install a fan for the video card or exchange video RAM
1005 10) install a better fan for the CPU
1006 11) exchange RAM chips
1007 12) exchange the motherboard.
1009 To compile this driver as a module, choose M here: the
1010 module will be called apm.
1014 config APM_IGNORE_USER_SUSPEND
1015 bool "Ignore USER SUSPEND"
1017 This option will ignore USER SUSPEND requests. On machines with a
1018 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1019 series notebooks, it is necessary to say Y because of a BIOS bug.
1021 config APM_DO_ENABLE
1022 bool "Enable PM at boot time"
1024 Enable APM features at boot time. From page 36 of the APM BIOS
1025 specification: "When disabled, the APM BIOS does not automatically
1026 power manage devices, enter the Standby State, enter the Suspend
1027 State, or take power saving steps in response to CPU Idle calls."
1028 This driver will make CPU Idle calls when Linux is idle (unless this
1029 feature is turned off -- see "Do CPU IDLE calls", below). This
1030 should always save battery power, but more complicated APM features
1031 will be dependent on your BIOS implementation. You may need to turn
1032 this option off if your computer hangs at boot time when using APM
1033 support, or if it beeps continuously instead of suspending. Turn
1034 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1035 T400CDT. This is off by default since most machines do fine without
1039 bool "Make CPU Idle calls when idle"
1041 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1042 On some machines, this can activate improved power savings, such as
1043 a slowed CPU clock rate, when the machine is idle. These idle calls
1044 are made after the idle loop has run for some length of time (e.g.,
1045 333 mS). On some machines, this will cause a hang at boot time or
1046 whenever the CPU becomes idle. (On machines with more than one CPU,
1047 this option does nothing.)
1049 config APM_DISPLAY_BLANK
1050 bool "Enable console blanking using APM"
1052 Enable console blanking using the APM. Some laptops can use this to
1053 turn off the LCD backlight when the screen blanker of the Linux
1054 virtual console blanks the screen. Note that this is only used by
1055 the virtual console screen blanker, and won't turn off the backlight
1056 when using the X Window system. This also doesn't have anything to
1057 do with your VESA-compliant power-saving monitor. Further, this
1058 option doesn't work for all laptops -- it might not turn off your
1059 backlight at all, or it might print a lot of errors to the console,
1060 especially if you are using gpm.
1062 config APM_ALLOW_INTS
1063 bool "Allow interrupts during APM BIOS calls"
1065 Normally we disable external interrupts while we are making calls to
1066 the APM BIOS as a measure to lessen the effects of a badly behaving
1067 BIOS implementation. The BIOS should reenable interrupts if it
1068 needs to. Unfortunately, some BIOSes do not -- especially those in
1069 many of the newer IBM Thinkpads. If you experience hangs when you
1070 suspend, try setting this to Y. Otherwise, say N.
1072 config APM_REAL_MODE_POWER_OFF
1073 bool "Use real mode APM BIOS call to power off"
1075 Use real mode APM BIOS calls to switch off the computer. This is
1076 a work-around for a number of buggy BIOSes. Switch this option on if
1077 your computer crashes instead of powering off properly.
1081 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1085 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1088 bool "PCI support" if !X86_VISWS
1089 depends on !X86_VOYAGER
1090 default y if X86_VISWS
1091 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1093 Find out whether you have a PCI motherboard. PCI is the name of a
1094 bus system, i.e. the way the CPU talks to the other stuff inside
1095 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1096 VESA. If you have PCI, say Y, otherwise N.
1098 The PCI-HOWTO, available from
1099 <http://www.tldp.org/docs.html#howto>, contains valuable
1100 information about which PCI hardware does work under Linux and which
1104 prompt "PCI access mode"
1105 depends on PCI && !X86_VISWS
1108 On PCI systems, the BIOS can be used to detect the PCI devices and
1109 determine their configuration. However, some old PCI motherboards
1110 have BIOS bugs and may crash if this is done. Also, some embedded
1111 PCI-based systems don't have any BIOS at all. Linux can also try to
1112 detect the PCI hardware directly without using the BIOS.
1114 With this option, you can specify how Linux should detect the
1115 PCI devices. If you choose "BIOS", the BIOS will be used,
1116 if you choose "Direct", the BIOS won't be used, and if you
1117 choose "MMConfig", then PCI Express MMCONFIG will be used.
1118 If you choose "Any", the kernel will try MMCONFIG, then the
1119 direct access method and falls back to the BIOS if that doesn't
1120 work. If unsure, go with the default, which is "Any".
1125 config PCI_GOMMCONFIG
1138 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1143 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1148 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1156 source "drivers/pci/pcie/Kconfig"
1158 source "drivers/pci/Kconfig"
1166 depends on !(X86_VOYAGER || X86_VISWS)
1168 Find out whether you have ISA slots on your motherboard. ISA is the
1169 name of a bus system, i.e. the way the CPU talks to the other stuff
1170 inside your box. Other bus systems are PCI, EISA, MicroChannel
1171 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1172 newer boards don't support it. If you have ISA, say Y, otherwise N.
1178 The Extended Industry Standard Architecture (EISA) bus was
1179 developed as an open alternative to the IBM MicroChannel bus.
1181 The EISA bus provided some of the features of the IBM MicroChannel
1182 bus while maintaining backward compatibility with cards made for
1183 the older ISA bus. The EISA bus saw limited use between 1988 and
1184 1995 when it was made obsolete by the PCI bus.
1186 Say Y here if you are building a kernel for an EISA-based machine.
1190 source "drivers/eisa/Kconfig"
1193 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1194 default y if X86_VOYAGER
1196 MicroChannel Architecture is found in some IBM PS/2 machines and
1197 laptops. It is a bus system similar to PCI or ISA. See
1198 <file:Documentation/mca.txt> (and especially the web page given
1199 there) before attempting to build an MCA bus kernel.
1201 source "drivers/mca/Kconfig"
1204 tristate "NatSemi SCx200 support"
1205 depends on !X86_VOYAGER
1207 This provides basic support for National Semiconductor's
1208 (now AMD's) Geode processors. The driver probes for the
1209 PCI-IDs of several on-chip devices, so its a good dependency
1210 for other scx200_* drivers.
1212 If compiled as a module, the driver is named scx200.
1214 config SCx200HR_TIMER
1215 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1216 depends on SCx200 && GENERIC_TIME
1219 This driver provides a clocksource built upon the on-chip
1220 27MHz high-resolution timer. Its also a workaround for
1221 NSC Geode SC-1100's buggy TSC, which loses time when the
1222 processor goes idle (as is done by the scheduler). The
1223 other workaround is idle=poll boot option.
1225 config GEODE_MFGPT_TIMER
1226 bool "Geode Multi-Function General Purpose Timer (MFGPT) events"
1227 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1230 This driver provides a clock event source based on the MFGPT
1231 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1232 MFGPTs have a better resolution and max interval than the
1233 generic PIT, and are suitable for use as high-res timers.
1237 depends on AGP_AMD64
1239 source "drivers/pcmcia/Kconfig"
1241 source "drivers/pci/hotplug/Kconfig"
1245 menu "Executable file formats"
1247 source "fs/Kconfig.binfmt"
1251 source "net/Kconfig"
1253 source "drivers/Kconfig"
1257 menuconfig INSTRUMENTATION
1258 bool "Instrumentation Support"
1261 Say Y here to get to see options related to performance measurement,
1262 debugging, and testing. This option alone does not add any kernel code.
1264 If you say N, all options in this submenu will be skipped and disabled.
1268 source "arch/x86/oprofile/Kconfig"
1272 depends on KALLSYMS && MODULES
1274 Kprobes allows you to trap at almost any kernel address and
1275 execute a callback function. register_kprobe() establishes
1276 a probepoint and specifies the callback. Kprobes is useful
1277 for kernel debugging, non-intrusive instrumentation and testing.
1278 If in doubt, say "N".
1280 endif # INSTRUMENTATION
1282 source "arch/i386/Kconfig.debug"
1284 source "security/Kconfig"
1286 source "crypto/Kconfig"
1288 source "lib/Kconfig"
1291 # Use the generic interrupt handling code in kernel/irq/:
1293 config GENERIC_HARDIRQS
1297 config GENERIC_IRQ_PROBE
1301 config GENERIC_PENDING_IRQ
1303 depends on GENERIC_HARDIRQS && SMP
1308 depends on SMP && !X86_VOYAGER
1313 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1316 config X86_BIOS_REBOOT
1318 depends on !(X86_VISWS || X86_VOYAGER)
1321 config X86_TRAMPOLINE
1323 depends on X86_SMP || (X86_VOYAGER && SMP)
projects / firefly-linux-kernel-4.4.55.git / blob