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
47 config LOCKDEP_SUPPORT
51 config STACKTRACE_SUPPORT
55 config SEMAPHORE_SLEEPERS
73 config RWSEM_GENERIC_SPINLOCK
77 config RWSEM_XCHGADD_ALGORITHM
80 config GENERIC_HWEIGHT
84 config GENERIC_CALIBRATE_DELAY
96 config GENERIC_ISA_DMA
104 config ARCH_MAY_HAVE_PC_FDC
108 config ARCH_POPULATES_NODE_MAP
124 config ARCH_HAS_ILOG2_U32
128 config ARCH_HAS_ILOG2_U64
132 source "init/Kconfig"
135 menu "Processor type and features"
138 prompt "Subarchitecture Type"
144 Choose this option if your computer is a standard PC or compatible.
147 bool "Support for ScaleMP vSMP"
150 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
151 supposed to run on these EM64T-based machines. Only choose this option
152 if you have one of these machines.
157 prompt "Processor family"
161 bool "AMD-Opteron/Athlon64"
163 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
166 bool "Intel P4 / older Netburst based Xeon"
168 Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
169 with Intel Extended Memory 64 Technology(EM64T). For details see
170 <http://www.intel.com/technology/64bitextensions/>.
171 Note that the latest Xeons (Xeon 51xx and 53xx) are not based on the
172 Netburst core and shouldn't use this option. You can distinguish them
173 using the cpu family field
174 in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one
175 (this rule only applies to systems that support EM64T)
178 bool "Intel Core2 / newer Xeon"
180 Optimize for Intel Core2 and newer Xeons (51xx)
181 You can distinguish the newer Xeons from the older ones using
182 the cpu family field in /proc/cpuinfo. 15 is an older Xeon
183 (use CONFIG_MPSC then), 6 is a newer one. This rule only
184 applies to CPUs that support EM64T.
187 bool "Generic-x86-64"
190 Run equally well on all x86-64 CPUs.
195 # Define implied options from the CPU selection here
197 config X86_L1_CACHE_BYTES
199 default "128" if GENERIC_CPU || MPSC
200 default "64" if MK8 || MCORE2
202 config X86_L1_CACHE_SHIFT
204 default "7" if GENERIC_CPU || MPSC
205 default "6" if MK8 || MCORE2
207 config X86_INTERNODE_CACHE_BYTES
209 default "4096" if X86_VSMP
210 default X86_L1_CACHE_BYTES if !X86_VSMP
221 tristate "/dev/cpu/microcode - Intel CPU microcode support"
224 If you say Y here the 'File systems' section, you will be
225 able to update the microcode on Intel processors. You will
226 obviously need the actual microcode binary data itself which is
227 not shipped with the Linux kernel.
229 For latest news and information on obtaining all the required
230 ingredients for this driver, check:
231 <http://www.urbanmyth.org/microcode/>.
233 To compile this driver as a module, choose M here: the
234 module will be called microcode.
235 If you use modprobe or kmod you may also want to add the line
236 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
238 config MICROCODE_OLD_INTERFACE
244 tristate "/dev/cpu/*/msr - Model-specific register support"
246 This device gives privileged processes access to the x86
247 Model-Specific Registers (MSRs). It is a character device with
248 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
249 MSR accesses are directed to a specific CPU on multi-processor
253 tristate "/dev/cpu/*/cpuid - CPU information support"
255 This device gives processes access to the x86 CPUID instruction to
256 be executed on a specific processor. It is a character device
257 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
262 depends on SMP && !MK8
265 config MATH_EMULATION
278 config X86_LOCAL_APIC
283 bool "MTRR (Memory Type Range Register) support"
285 On Intel P6 family processors (Pentium Pro, Pentium II and later)
286 the Memory Type Range Registers (MTRRs) may be used to control
287 processor access to memory ranges. This is most useful if you have
288 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
289 allows bus write transfers to be combined into a larger transfer
290 before bursting over the PCI/AGP bus. This can increase performance
291 of image write operations 2.5 times or more. Saying Y here creates a
292 /proc/mtrr file which may be used to manipulate your processor's
293 MTRRs. Typically the X server should use this.
295 This code has a reasonably generic interface so that similar
296 control registers on other processors can be easily supported
299 Saying Y here also fixes a problem with buggy SMP BIOSes which only
300 set the MTRRs for the boot CPU and not for the secondary CPUs. This
301 can lead to all sorts of problems, so it's good to say Y here.
303 Just say Y here, all x86-64 machines support MTRRs.
305 See <file:Documentation/mtrr.txt> for more information.
308 bool "Symmetric multi-processing support"
310 This enables support for systems with more than one CPU. If you have
311 a system with only one CPU, like most personal computers, say N. If
312 you have a system with more than one CPU, say Y.
314 If you say N here, the kernel will run on single and multiprocessor
315 machines, but will use only one CPU of a multiprocessor machine. If
316 you say Y here, the kernel will run on many, but not all,
317 singleprocessor machines. On a singleprocessor machine, the kernel
318 will run faster if you say N here.
320 If you don't know what to do here, say N.
323 bool "SMT (Hyperthreading) scheduler support"
327 SMT scheduler support improves the CPU scheduler's decision making
328 when dealing with Intel Pentium 4 chips with HyperThreading at a
329 cost of slightly increased overhead in some places. If unsure say
333 bool "Multi-core scheduler support"
337 Multi-core scheduler support improves the CPU scheduler's decision
338 making when dealing with multi-core CPU chips at a cost of slightly
339 increased overhead in some places. If unsure say N here.
341 source "kernel/Kconfig.preempt"
344 bool "Non Uniform Memory Access (NUMA) Support"
347 Enable NUMA (Non Uniform Memory Access) support. The kernel
348 will try to allocate memory used by a CPU on the local memory
349 controller of the CPU and add some more NUMA awareness to the kernel.
350 This code is recommended on all multiprocessor Opteron systems.
351 If the system is EM64T, you should say N unless your system is EM64T
355 bool "Old style AMD Opteron NUMA detection"
356 depends on NUMA && PCI
359 Enable K8 NUMA node topology detection. You should say Y here if
360 you have a multi processor AMD K8 system. This uses an old
361 method to read the NUMA configuration directly from the builtin
362 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
363 instead, which also takes priority if both are compiled in.
368 depends on NEED_MULTIPLE_NODES
370 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
372 config X86_64_ACPI_NUMA
373 bool "ACPI NUMA detection"
380 Enable ACPI SRAT based node topology detection.
383 bool "NUMA emulation"
386 Enable NUMA emulation. A flat machine will be split
387 into virtual nodes when booted with "numa=fake=N", where N is the
388 number of nodes. This is only useful for debugging.
390 config ARCH_DISCONTIGMEM_ENABLE
395 config ARCH_DISCONTIGMEM_DEFAULT
399 config ARCH_SPARSEMEM_ENABLE
401 depends on (NUMA || EXPERIMENTAL)
403 config ARCH_MEMORY_PROBE
405 depends on MEMORY_HOTPLUG
407 config ARCH_FLATMEM_ENABLE
413 config MEMORY_HOTPLUG_RESERVE
415 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
417 config HAVE_ARCH_EARLY_PFN_TO_NID
421 config OUT_OF_LINE_PFN_TO_PAGE
423 depends on DISCONTIGMEM
426 int "Maximum number of CPUs (2-255)"
431 This allows you to specify the maximum number of CPUs which this
432 kernel will support. Current maximum is 255 CPUs due to
433 APIC addressing limits. Less depending on the hardware.
435 This is purely to save memory - each supported CPU requires
436 memory in the static kernel configuration.
438 config PHYSICAL_ALIGN
443 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
444 depends on SMP && HOTPLUG && EXPERIMENTAL
446 Say Y here to experiment with turning CPUs off and on. CPUs
447 can be controlled through /sys/devices/system/cpu/cpu#.
448 This is also required for suspend/hibernation on SMP systems.
450 Say N if you want to disable CPU hotplug and don't need to
453 config ARCH_ENABLE_MEMORY_HOTPLUG
460 Use the IA-PC HPET (High Precision Event Timer) to manage
461 time in preference to the PIT and RTC, if a HPET is
462 present. The HPET provides a stable time base on SMP
463 systems, unlike the TSC, but it is more expensive to access,
464 as it is off-chip. You can find the HPET spec at
465 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
467 config HPET_EMULATE_RTC
468 bool "Provide RTC interrupt"
469 depends on HPET_TIMER && RTC=y
471 # Mark as embedded because too many people got it wrong.
472 # The code disables itself when not needed.
474 bool "IOMMU support" if EMBEDDED
480 Support for full DMA access of devices with 32bit memory access only
481 on systems with more than 3GB. This is usually needed for USB,
482 sound, many IDE/SATA chipsets and some other devices.
483 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
484 based hardware IOMMU and a software bounce buffer based IOMMU used
485 on Intel systems and as fallback.
486 The code is only active when needed (enough memory and limited
487 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
491 bool "IBM Calgary IOMMU support"
493 depends on PCI && EXPERIMENTAL
495 Support for hardware IOMMUs in IBM's xSeries x366 and x460
496 systems. Needed to run systems with more than 3GB of memory
497 properly with 32-bit PCI devices that do not support DAC
498 (Double Address Cycle). Calgary also supports bus level
499 isolation, where all DMAs pass through the IOMMU. This
500 prevents them from going anywhere except their intended
501 destination. This catches hard-to-find kernel bugs and
502 mis-behaving drivers and devices that do not use the DMA-API
503 properly to set up their DMA buffers. The IOMMU can be
504 turned off at boot time with the iommu=off parameter.
505 Normally the kernel will make the right choice by itself.
508 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
509 bool "Should Calgary be enabled by default?"
511 depends on CALGARY_IOMMU
513 Should Calgary be enabled by default? if you choose 'y', Calgary
514 will be used (if it exists). If you choose 'n', Calgary will not be
515 used even if it exists. If you choose 'n' and would like to use
516 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
519 # need this always selected by IOMMU for the VIA workaround
523 Support for software bounce buffers used on x86-64 systems
524 which don't have a hardware IOMMU (e.g. the current generation
525 of Intel's x86-64 CPUs). Using this PCI devices which can only
526 access 32-bits of memory can be used on systems with more than
527 3 GB of memory. If unsure, say Y.
530 bool "Machine check support" if EMBEDDED
533 Include a machine check error handler to report hardware errors.
534 This version will require the mcelog utility to decode some
535 machine check error logs. See
536 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
539 bool "Intel MCE features"
540 depends on X86_MCE && X86_LOCAL_APIC
543 Additional support for intel specific MCE features such as
547 bool "AMD MCE features"
548 depends on X86_MCE && X86_LOCAL_APIC
551 Additional support for AMD specific MCE features such as
552 the DRAM Error Threshold.
555 bool "kexec system call"
557 kexec is a system call that implements the ability to shutdown your
558 current kernel, and to start another kernel. It is like a reboot
559 but it is independent of the system firmware. And like a reboot
560 you can start any kernel with it, not just Linux.
562 The name comes from the similarity to the exec system call.
564 It is an ongoing process to be certain the hardware in a machine
565 is properly shutdown, so do not be surprised if this code does not
566 initially work for you. It may help to enable device hotplugging
567 support. As of this writing the exact hardware interface is
568 strongly in flux, so no good recommendation can be made.
571 bool "kernel crash dumps (EXPERIMENTAL)"
572 depends on EXPERIMENTAL
574 Generate crash dump after being started by kexec.
575 This should be normally only set in special crash dump kernels
576 which are loaded in the main kernel with kexec-tools into
577 a specially reserved region and then later executed after
578 a crash by kdump/kexec. The crash dump kernel must be compiled
579 to a memory address not used by the main kernel or BIOS using
581 For more details see Documentation/kdump/kdump.txt
584 bool "Build a relocatable kernel(EXPERIMENTAL)"
585 depends on EXPERIMENTAL
587 Builds a relocatable kernel. This enables loading and running
588 a kernel binary from a different physical address than it has
591 One use is for the kexec on panic case where the recovery kernel
592 must live at a different physical address than the primary
595 Note: If CONFIG_RELOCATABLE=y, then kernel run from the address
596 it has been loaded at and compile time physical address
597 (CONFIG_PHYSICAL_START) is ignored.
599 config PHYSICAL_START
600 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
603 This gives the physical address where the kernel is loaded. It
604 should be aligned to 2MB boundary.
606 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
607 bzImage will decompress itself to above physical address and
608 run from there. Otherwise, bzImage will run from the address where
609 it has been loaded by the boot loader and will ignore above physical
612 In normal kdump cases one does not have to set/change this option
613 as now bzImage can be compiled as a completely relocatable image
614 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
615 address. This option is mainly useful for the folks who don't want
616 to use a bzImage for capturing the crash dump and want to use a
619 So if you are using bzImage for capturing the crash dump, leave
620 the value here unchanged to 0x200000 and set CONFIG_RELOCATABLE=y.
621 Otherwise if you plan to use vmlinux for capturing the crash dump
622 change this value to start of the reserved region (Typically 16MB
623 0x1000000). In other words, it can be set based on the "X" value as
624 specified in the "crashkernel=YM@XM" command line boot parameter
625 passed to the panic-ed kernel. Typically this parameter is set as
626 crashkernel=64M@16M. Please take a look at
627 Documentation/kdump/kdump.txt for more details about crash dumps.
629 Usage of bzImage for capturing the crash dump is advantageous as
630 one does not have to build two kernels. Same kernel can be used
631 as production kernel and capture kernel.
633 Don't change this unless you know what you are doing.
636 bool "Enable seccomp to safely compute untrusted bytecode"
640 This kernel feature is useful for number crunching applications
641 that may need to compute untrusted bytecode during their
642 execution. By using pipes or other transports made available to
643 the process as file descriptors supporting the read/write
644 syscalls, it's possible to isolate those applications in
645 their own address space using seccomp. Once seccomp is
646 enabled via /proc/<pid>/seccomp, it cannot be disabled
647 and the task is only allowed to execute a few safe syscalls
648 defined by each seccomp mode.
650 If unsure, say Y. Only embedded should say N here.
652 config CC_STACKPROTECTOR
653 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
654 depends on EXPERIMENTAL
656 This option turns on the -fstack-protector GCC feature. This
657 feature puts, at the beginning of critical functions, a canary
658 value on the stack just before the return address, and validates
659 the value just before actually returning. Stack based buffer
660 overflows (that need to overwrite this return address) now also
661 overwrite the canary, which gets detected and the attack is then
662 neutralized via a kernel panic.
664 This feature requires gcc version 4.2 or above, or a distribution
665 gcc with the feature backported. Older versions are automatically
666 detected and for those versions, this configuration option is ignored.
668 config CC_STACKPROTECTOR_ALL
669 bool "Use stack-protector for all functions"
670 depends on CC_STACKPROTECTOR
672 Normally, GCC only inserts the canary value protection for
673 functions that use large-ish on-stack buffers. By enabling
674 this option, GCC will be asked to do this for ALL functions.
676 source kernel/Kconfig.hz
680 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
685 # Use the generic interrupt handling code in kernel/irq/:
687 config GENERIC_HARDIRQS
691 config GENERIC_IRQ_PROBE
695 # we have no ISA slots, but we do have ISA-style DMA.
700 config GENERIC_PENDING_IRQ
702 depends on GENERIC_HARDIRQS && SMP
705 menu "Power management options"
707 source kernel/power/Kconfig
709 source "drivers/acpi/Kconfig"
711 source "arch/x86/kernel/cpufreq/Kconfig"
715 menu "Bus options (PCI etc.)"
719 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
721 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
728 bool "Support mmconfig PCI config space access"
729 depends on PCI && ACPI
731 source "drivers/pci/pcie/Kconfig"
733 source "drivers/pci/Kconfig"
735 source "drivers/pcmcia/Kconfig"
737 source "drivers/pci/hotplug/Kconfig"
742 menu "Executable file formats / Emulations"
744 source "fs/Kconfig.binfmt"
746 config IA32_EMULATION
747 bool "IA32 Emulation"
749 Include code to run 32-bit programs under a 64-bit kernel. You should likely
750 turn this on, unless you're 100% sure that you don't have any 32-bit programs
754 tristate "IA32 a.out support"
755 depends on IA32_EMULATION
757 Support old a.out binaries in the 32bit emulation.
761 depends on IA32_EMULATION
764 config COMPAT_FOR_U64_ALIGNMENT
767 config SYSVIPC_COMPAT
769 depends on COMPAT && SYSVIPC
776 source drivers/Kconfig
778 source "drivers/firmware/Kconfig"
782 menu "Instrumentation Support"
783 depends on EXPERIMENTAL
785 source "arch/x86/oprofile/Kconfig"
789 depends on KALLSYMS && MODULES
791 Kprobes allows you to trap at almost any kernel address and
792 execute a callback function. register_kprobe() establishes
793 a probepoint and specifies the callback. Kprobes is useful
794 for kernel debugging, non-intrusive instrumentation and testing.
795 If in doubt, say "N".
798 source "arch/x86_64/Kconfig.debug"
800 source "security/Kconfig"
802 source "crypto/Kconfig"