2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
5 # Note: ISA is disabled and will hopefully never be enabled.
6 # If you managed to buy an ISA x86-64 box you'll have to fix all the
7 # ISA drivers you need yourself.
10 mainmenu "Linux Kernel Configuration"
16 Port to the x86-64 architecture. x86-64 is a 64-bit extension to the
17 classical 32-bit x86 architecture. For details see
18 <http://www.x86-64.org/>.
31 config GENERIC_TIME_VSYSCALL
35 config GENERIC_CMOS_UPDATE
39 config CLOCKSOURCE_WATCHDOG
43 config GENERIC_CLOCKEVENTS
47 config GENERIC_CLOCKEVENTS_BROADCAST
55 config LOCKDEP_SUPPORT
59 config STACKTRACE_SUPPORT
63 config SEMAPHORE_SLEEPERS
81 config RWSEM_GENERIC_SPINLOCK
85 config RWSEM_XCHGADD_ALGORITHM
88 config GENERIC_HWEIGHT
92 config GENERIC_CALIBRATE_DELAY
104 config GENERIC_ISA_DMA
112 config ARCH_MAY_HAVE_PC_FDC
116 config ARCH_POPULATES_NODE_MAP
132 config ARCH_HAS_ILOG2_U32
136 config ARCH_HAS_ILOG2_U64
140 source "init/Kconfig"
143 menu "Processor type and features"
145 source "kernel/time/Kconfig"
148 prompt "Subarchitecture Type"
154 Choose this option if your computer is a standard PC or compatible.
157 bool "Support for ScaleMP vSMP"
160 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
161 supposed to run on these EM64T-based machines. Only choose this option
162 if you have one of these machines.
167 prompt "Processor family"
171 bool "AMD-Opteron/Athlon64"
173 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
176 bool "Intel P4 / older Netburst based Xeon"
178 Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
179 with Intel Extended Memory 64 Technology(EM64T). For details see
180 <http://www.intel.com/technology/64bitextensions/>.
181 Note that the latest Xeons (Xeon 51xx and 53xx) are not based on the
182 Netburst core and shouldn't use this option. You can distinguish them
183 using the cpu family field
184 in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one
185 (this rule only applies to systems that support EM64T)
188 bool "Intel Core2 / newer Xeon"
190 Optimize for Intel Core2 and newer Xeons (51xx)
191 You can distinguish the newer Xeons from the older ones using
192 the cpu family field in /proc/cpuinfo. 15 is an older Xeon
193 (use CONFIG_MPSC then), 6 is a newer one. This rule only
194 applies to CPUs that support EM64T.
197 bool "Generic-x86-64"
200 Run equally well on all x86-64 CPUs.
205 # Define implied options from the CPU selection here
207 config X86_L1_CACHE_BYTES
209 default "128" if GENERIC_CPU || MPSC
210 default "64" if MK8 || MCORE2
212 config X86_L1_CACHE_SHIFT
214 default "7" if GENERIC_CPU || MPSC
215 default "6" if MK8 || MCORE2
217 config X86_INTERNODE_CACHE_BYTES
219 default "4096" if X86_VSMP
220 default X86_L1_CACHE_BYTES if !X86_VSMP
231 tristate "/dev/cpu/microcode - Intel CPU microcode support"
234 If you say Y here the 'File systems' section, you will be
235 able to update the microcode on Intel processors. You will
236 obviously need the actual microcode binary data itself which is
237 not shipped with the Linux kernel.
239 For latest news and information on obtaining all the required
240 ingredients for this driver, check:
241 <http://www.urbanmyth.org/microcode/>.
243 To compile this driver as a module, choose M here: the
244 module will be called microcode.
245 If you use modprobe or kmod you may also want to add the line
246 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
248 config MICROCODE_OLD_INTERFACE
254 tristate "/dev/cpu/*/msr - Model-specific register support"
256 This device gives privileged processes access to the x86
257 Model-Specific Registers (MSRs). It is a character device with
258 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
259 MSR accesses are directed to a specific CPU on multi-processor
263 tristate "/dev/cpu/*/cpuid - CPU information support"
265 This device gives processes access to the x86 CPUID instruction to
266 be executed on a specific processor. It is a character device
267 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
272 depends on SMP && !MK8
275 config MATH_EMULATION
288 config X86_LOCAL_APIC
293 bool "MTRR (Memory Type Range Register) support"
295 On Intel P6 family processors (Pentium Pro, Pentium II and later)
296 the Memory Type Range Registers (MTRRs) may be used to control
297 processor access to memory ranges. This is most useful if you have
298 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
299 allows bus write transfers to be combined into a larger transfer
300 before bursting over the PCI/AGP bus. This can increase performance
301 of image write operations 2.5 times or more. Saying Y here creates a
302 /proc/mtrr file which may be used to manipulate your processor's
303 MTRRs. Typically the X server should use this.
305 This code has a reasonably generic interface so that similar
306 control registers on other processors can be easily supported
309 Saying Y here also fixes a problem with buggy SMP BIOSes which only
310 set the MTRRs for the boot CPU and not for the secondary CPUs. This
311 can lead to all sorts of problems, so it's good to say Y here.
313 Just say Y here, all x86-64 machines support MTRRs.
315 See <file:Documentation/mtrr.txt> for more information.
318 bool "Symmetric multi-processing support"
320 This enables support for systems with more than one CPU. If you have
321 a system with only one CPU, like most personal computers, say N. If
322 you have a system with more than one CPU, say Y.
324 If you say N here, the kernel will run on single and multiprocessor
325 machines, but will use only one CPU of a multiprocessor machine. If
326 you say Y here, the kernel will run on many, but not all,
327 singleprocessor machines. On a singleprocessor machine, the kernel
328 will run faster if you say N here.
330 If you don't know what to do here, say N.
333 bool "SMT (Hyperthreading) scheduler support"
337 SMT scheduler support improves the CPU scheduler's decision making
338 when dealing with Intel Pentium 4 chips with HyperThreading at a
339 cost of slightly increased overhead in some places. If unsure say
343 bool "Multi-core scheduler support"
347 Multi-core scheduler support improves the CPU scheduler's decision
348 making when dealing with multi-core CPU chips at a cost of slightly
349 increased overhead in some places. If unsure say N here.
351 source "kernel/Kconfig.preempt"
354 bool "Non Uniform Memory Access (NUMA) Support"
357 Enable NUMA (Non Uniform Memory Access) support. The kernel
358 will try to allocate memory used by a CPU on the local memory
359 controller of the CPU and add some more NUMA awareness to the kernel.
360 This code is recommended on all multiprocessor Opteron systems.
361 If the system is EM64T, you should say N unless your system is EM64T
365 bool "Old style AMD Opteron NUMA detection"
366 depends on NUMA && PCI
369 Enable K8 NUMA node topology detection. You should say Y here if
370 you have a multi processor AMD K8 system. This uses an old
371 method to read the NUMA configuration directly from the builtin
372 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
373 instead, which also takes priority if both are compiled in.
378 depends on NEED_MULTIPLE_NODES
380 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
382 config X86_64_ACPI_NUMA
383 bool "ACPI NUMA detection"
390 Enable ACPI SRAT based node topology detection.
393 bool "NUMA emulation"
396 Enable NUMA emulation. A flat machine will be split
397 into virtual nodes when booted with "numa=fake=N", where N is the
398 number of nodes. This is only useful for debugging.
400 config ARCH_DISCONTIGMEM_ENABLE
405 config ARCH_DISCONTIGMEM_DEFAULT
409 config ARCH_SPARSEMEM_ENABLE
411 depends on (NUMA || EXPERIMENTAL)
412 select SPARSEMEM_VMEMMAP_ENABLE
414 config ARCH_MEMORY_PROBE
416 depends on MEMORY_HOTPLUG
418 config ARCH_FLATMEM_ENABLE
424 config MEMORY_HOTPLUG_RESERVE
426 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
428 config HAVE_ARCH_EARLY_PFN_TO_NID
432 config OUT_OF_LINE_PFN_TO_PAGE
434 depends on DISCONTIGMEM
437 int "Maximum number of CPUs (2-255)"
442 This allows you to specify the maximum number of CPUs which this
443 kernel will support. Current maximum is 255 CPUs due to
444 APIC addressing limits. Less depending on the hardware.
446 This is purely to save memory - each supported CPU requires
447 memory in the static kernel configuration.
449 config PHYSICAL_ALIGN
454 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
455 depends on SMP && HOTPLUG && EXPERIMENTAL
457 Say Y here to experiment with turning CPUs off and on. CPUs
458 can be controlled through /sys/devices/system/cpu/cpu#.
459 This is also required for suspend/hibernation on SMP systems.
461 Say N if you want to disable CPU hotplug and don't need to
464 config ARCH_ENABLE_MEMORY_HOTPLUG
471 Use the IA-PC HPET (High Precision Event Timer) to manage
472 time in preference to the PIT and RTC, if a HPET is
473 present. The HPET provides a stable time base on SMP
474 systems, unlike the TSC, but it is more expensive to access,
475 as it is off-chip. You can find the HPET spec at
476 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
478 config HPET_EMULATE_RTC
479 bool "Provide RTC interrupt"
480 depends on HPET_TIMER && RTC=y
482 # Mark as embedded because too many people got it wrong.
483 # The code disables itself when not needed.
485 bool "IOMMU support" if EMBEDDED
491 Support for full DMA access of devices with 32bit memory access only
492 on systems with more than 3GB. This is usually needed for USB,
493 sound, many IDE/SATA chipsets and some other devices.
494 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
495 based hardware IOMMU and a software bounce buffer based IOMMU used
496 on Intel systems and as fallback.
497 The code is only active when needed (enough memory and limited
498 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
502 bool "IBM Calgary IOMMU support"
504 depends on PCI && EXPERIMENTAL
506 Support for hardware IOMMUs in IBM's xSeries x366 and x460
507 systems. Needed to run systems with more than 3GB of memory
508 properly with 32-bit PCI devices that do not support DAC
509 (Double Address Cycle). Calgary also supports bus level
510 isolation, where all DMAs pass through the IOMMU. This
511 prevents them from going anywhere except their intended
512 destination. This catches hard-to-find kernel bugs and
513 mis-behaving drivers and devices that do not use the DMA-API
514 properly to set up their DMA buffers. The IOMMU can be
515 turned off at boot time with the iommu=off parameter.
516 Normally the kernel will make the right choice by itself.
519 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
520 bool "Should Calgary be enabled by default?"
522 depends on CALGARY_IOMMU
524 Should Calgary be enabled by default? if you choose 'y', Calgary
525 will be used (if it exists). If you choose 'n', Calgary will not be
526 used even if it exists. If you choose 'n' and would like to use
527 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
530 # need this always selected by IOMMU for the VIA workaround
534 Support for software bounce buffers used on x86-64 systems
535 which don't have a hardware IOMMU (e.g. the current generation
536 of Intel's x86-64 CPUs). Using this PCI devices which can only
537 access 32-bits of memory can be used on systems with more than
538 3 GB of memory. If unsure, say Y.
541 bool "Machine check support" if EMBEDDED
544 Include a machine check error handler to report hardware errors.
545 This version will require the mcelog utility to decode some
546 machine check error logs. See
547 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
550 bool "Intel MCE features"
551 depends on X86_MCE && X86_LOCAL_APIC
554 Additional support for intel specific MCE features such as
558 bool "AMD MCE features"
559 depends on X86_MCE && X86_LOCAL_APIC
562 Additional support for AMD specific MCE features such as
563 the DRAM Error Threshold.
566 bool "kexec system call"
568 kexec is a system call that implements the ability to shutdown your
569 current kernel, and to start another kernel. It is like a reboot
570 but it is independent of the system firmware. And like a reboot
571 you can start any kernel with it, not just Linux.
573 The name comes from the similarity to the exec system call.
575 It is an ongoing process to be certain the hardware in a machine
576 is properly shutdown, so do not be surprised if this code does not
577 initially work for you. It may help to enable device hotplugging
578 support. As of this writing the exact hardware interface is
579 strongly in flux, so no good recommendation can be made.
582 bool "kernel crash dumps (EXPERIMENTAL)"
583 depends on EXPERIMENTAL
585 Generate crash dump after being started by kexec.
586 This should be normally only set in special crash dump kernels
587 which are loaded in the main kernel with kexec-tools into
588 a specially reserved region and then later executed after
589 a crash by kdump/kexec. The crash dump kernel must be compiled
590 to a memory address not used by the main kernel or BIOS using
592 For more details see Documentation/kdump/kdump.txt
595 bool "Build a relocatable kernel(EXPERIMENTAL)"
596 depends on EXPERIMENTAL
598 Builds a relocatable kernel. This enables loading and running
599 a kernel binary from a different physical address than it has
602 One use is for the kexec on panic case where the recovery kernel
603 must live at a different physical address than the primary
606 Note: If CONFIG_RELOCATABLE=y, then kernel run from the address
607 it has been loaded at and compile time physical address
608 (CONFIG_PHYSICAL_START) is ignored.
610 config PHYSICAL_START
611 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
614 This gives the physical address where the kernel is loaded. It
615 should be aligned to 2MB boundary.
617 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
618 bzImage will decompress itself to above physical address and
619 run from there. Otherwise, bzImage will run from the address where
620 it has been loaded by the boot loader and will ignore above physical
623 In normal kdump cases one does not have to set/change this option
624 as now bzImage can be compiled as a completely relocatable image
625 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
626 address. This option is mainly useful for the folks who don't want
627 to use a bzImage for capturing the crash dump and want to use a
630 So if you are using bzImage for capturing the crash dump, leave
631 the value here unchanged to 0x200000 and set CONFIG_RELOCATABLE=y.
632 Otherwise if you plan to use vmlinux for capturing the crash dump
633 change this value to start of the reserved region (Typically 16MB
634 0x1000000). In other words, it can be set based on the "X" value as
635 specified in the "crashkernel=YM@XM" command line boot parameter
636 passed to the panic-ed kernel. Typically this parameter is set as
637 crashkernel=64M@16M. Please take a look at
638 Documentation/kdump/kdump.txt for more details about crash dumps.
640 Usage of bzImage for capturing the crash dump is advantageous as
641 one does not have to build two kernels. Same kernel can be used
642 as production kernel and capture kernel.
644 Don't change this unless you know what you are doing.
647 bool "Enable seccomp to safely compute untrusted bytecode"
651 This kernel feature is useful for number crunching applications
652 that may need to compute untrusted bytecode during their
653 execution. By using pipes or other transports made available to
654 the process as file descriptors supporting the read/write
655 syscalls, it's possible to isolate those applications in
656 their own address space using seccomp. Once seccomp is
657 enabled via /proc/<pid>/seccomp, it cannot be disabled
658 and the task is only allowed to execute a few safe syscalls
659 defined by each seccomp mode.
661 If unsure, say Y. Only embedded should say N here.
663 config CC_STACKPROTECTOR
664 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
665 depends on EXPERIMENTAL
667 This option turns on the -fstack-protector GCC feature. This
668 feature puts, at the beginning of critical functions, a canary
669 value on the stack just before the return address, and validates
670 the value just before actually returning. Stack based buffer
671 overflows (that need to overwrite this return address) now also
672 overwrite the canary, which gets detected and the attack is then
673 neutralized via a kernel panic.
675 This feature requires gcc version 4.2 or above, or a distribution
676 gcc with the feature backported. Older versions are automatically
677 detected and for those versions, this configuration option is ignored.
679 config CC_STACKPROTECTOR_ALL
680 bool "Use stack-protector for all functions"
681 depends on CC_STACKPROTECTOR
683 Normally, GCC only inserts the canary value protection for
684 functions that use large-ish on-stack buffers. By enabling
685 this option, GCC will be asked to do this for ALL functions.
687 source kernel/Kconfig.hz
691 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
696 # Use the generic interrupt handling code in kernel/irq/:
698 config GENERIC_HARDIRQS
702 config GENERIC_IRQ_PROBE
706 # we have no ISA slots, but we do have ISA-style DMA.
711 config GENERIC_PENDING_IRQ
713 depends on GENERIC_HARDIRQS && SMP
716 menu "Power management options"
718 source kernel/power/Kconfig
720 source "drivers/acpi/Kconfig"
722 source "arch/x86/kernel/cpufreq/Kconfig"
726 menu "Bus options (PCI etc.)"
730 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
732 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
739 bool "Support mmconfig PCI config space access"
740 depends on PCI && ACPI
747 source "drivers/pci/pcie/Kconfig"
749 source "drivers/pci/Kconfig"
751 source "drivers/pcmcia/Kconfig"
753 source "drivers/pci/hotplug/Kconfig"
758 menu "Executable file formats / Emulations"
760 source "fs/Kconfig.binfmt"
762 config IA32_EMULATION
763 bool "IA32 Emulation"
765 Include code to run 32-bit programs under a 64-bit kernel. You should likely
766 turn this on, unless you're 100% sure that you don't have any 32-bit programs
770 tristate "IA32 a.out support"
771 depends on IA32_EMULATION
773 Support old a.out binaries in the 32bit emulation.
777 depends on IA32_EMULATION
780 config COMPAT_FOR_U64_ALIGNMENT
783 config SYSVIPC_COMPAT
785 depends on COMPAT && SYSVIPC
792 source drivers/Kconfig
794 source "drivers/firmware/Kconfig"
798 menu "Instrumentation Support"
800 source "arch/x86/oprofile/Kconfig"
804 depends on KALLSYMS && MODULES
806 Kprobes allows you to trap at almost any kernel address and
807 execute a callback function. register_kprobe() establishes
808 a probepoint and specifies the callback. Kprobes is useful
809 for kernel debugging, non-intrusive instrumentation and testing.
810 If in doubt, say "N".
813 source "arch/x86_64/Kconfig.debug"
815 source "security/Kconfig"
817 source "crypto/Kconfig"