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 LOCKDEP_SUPPORT
35 config STACKTRACE_SUPPORT
37 depends on !X86_64_XEN
40 config SEMAPHORE_SLEEPERS
54 config RWSEM_GENERIC_SPINLOCK
58 config RWSEM_XCHGADD_ALGORITHM
61 config GENERIC_HWEIGHT
65 config GENERIC_CALIBRATE_DELAY
77 config GENERIC_ISA_DMA
85 config ARCH_MAY_HAVE_PC_FDC
89 config ARCH_POPULATES_NODE_MAP
105 config ARCH_HAS_ILOG2_U32
109 config ARCH_HAS_ILOG2_U64
113 source "init/Kconfig"
116 menu "Processor type and features"
119 prompt "Subarchitecture Type"
125 Choose this option if your computer is a standard PC or compatible.
128 bool "Support for ScaleMP vSMP"
131 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
132 supposed to run on these EM64T-based machines. Only choose this option
133 if you have one of these machines.
138 prompt "Processor family"
142 bool "AMD-Opteron/Athlon64"
144 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
147 bool "Intel P4 / older Netburst based Xeon"
149 Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
150 with Intel Extended Memory 64 Technology(EM64T). For details see
151 <http://www.intel.com/technology/64bitextensions/>.
152 Note the the latest Xeons (Xeon 51xx and 53xx) are not based on the
153 Netburst core and shouldn't use this option. You can distingush them
154 using the cpu family field
155 in /proc/cpuinfo. Family 15 is a older Xeon, Family 6 a newer one
156 (this rule only applies to system that support EM64T)
159 bool "Intel Core2 / newer Xeon"
161 Optimize for Intel Core2 and newer Xeons (51xx)
162 You can distingush the newer Xeons from the older ones using
163 the cpu family field in /proc/cpuinfo. 15 is a older Xeon
164 (use CONFIG_MPSC then), 6 is a newer one. This rule only
165 applies to CPUs that support EM64T.
168 bool "Generic-x86-64"
171 Run equally well on all x86-64 CPUs.
176 bool "Enable Xen compatible kernel"
179 This option will compile a kernel compatible with Xen hypervisor
183 depends on X86_64_XEN
188 depends on X86_64_XEN
192 # Define implied options from the CPU selection here
194 config X86_L1_CACHE_BYTES
196 default "128" if GENERIC_CPU || MPSC
197 default "64" if MK8 || MCORE2
199 config X86_L1_CACHE_SHIFT
201 default "7" if GENERIC_CPU || MPSC
202 default "6" if MK8 || MCORE2
204 config X86_INTERNODE_CACHE_BYTES
206 default "4096" if X86_VSMP
207 default X86_L1_CACHE_BYTES if !X86_VSMP
211 depends on !X86_64_XEN
219 tristate "/dev/cpu/microcode - Intel CPU microcode support"
222 If you say Y here the 'File systems' section, you will be
223 able to update the microcode on Intel processors. You will
224 obviously need the actual microcode binary data itself which is
225 not shipped with the Linux kernel.
227 For latest news and information on obtaining all the required
228 ingredients for this driver, check:
229 <http://www.urbanmyth.org/microcode/>.
231 To compile this driver as a module, choose M here: the
232 module will be called microcode.
233 If you use modprobe or kmod you may also want to add the line
234 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
236 config MICROCODE_OLD_INTERFACE
242 tristate "/dev/cpu/*/msr - Model-specific register support"
244 This device gives privileged processes access to the x86
245 Model-Specific Registers (MSRs). It is a character device with
246 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
247 MSR accesses are directed to a specific CPU on multi-processor
251 tristate "/dev/cpu/*/cpuid - CPU information support"
253 This device gives processes access to the x86 CPUID instruction to
254 be executed on a specific processor. It is a character device
255 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
260 depends on SMP && !MK8 && !X86_64_XEN
263 config MATH_EMULATION
274 depends !XEN_UNPRIVILEGED_GUEST
277 config X86_XEN_GENAPIC
280 default XEN_PRIVILEGED_GUEST || SMP
282 config X86_LOCAL_APIC
284 depends !XEN_UNPRIVILEGED_GUEST
288 bool "MTRR (Memory Type Range Register) support"
289 depends on !XEN_UNPRIVILEGED_GUEST
291 On Intel P6 family processors (Pentium Pro, Pentium II and later)
292 the Memory Type Range Registers (MTRRs) may be used to control
293 processor access to memory ranges. This is most useful if you have
294 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
295 allows bus write transfers to be combined into a larger transfer
296 before bursting over the PCI/AGP bus. This can increase performance
297 of image write operations 2.5 times or more. Saying Y here creates a
298 /proc/mtrr file which may be used to manipulate your processor's
299 MTRRs. Typically the X server should use this.
301 This code has a reasonably generic interface so that similar
302 control registers on other processors can be easily supported
305 Saying Y here also fixes a problem with buggy SMP BIOSes which only
306 set the MTRRs for the boot CPU and not for the secondary CPUs. This
307 can lead to all sorts of problems, so it's good to say Y here.
309 Just say Y here, all x86-64 machines support MTRRs.
311 See <file:Documentation/mtrr.txt> for more information.
314 bool "Symmetric multi-processing support"
316 This enables support for systems with more than one CPU. If you have
317 a system with only one CPU, like most personal computers, say N. If
318 you have a system with more than one CPU, say Y.
320 If you say N here, the kernel will run on single and multiprocessor
321 machines, but will use only one CPU of a multiprocessor machine. If
322 you say Y here, the kernel will run on many, but not all,
323 singleprocessor machines. On a singleprocessor machine, the kernel
324 will run faster if you say N here.
326 If you don't know what to do here, say N.
329 bool "SMT (Hyperthreading) scheduler support"
330 depends on SMP && !X86_64_XEN
333 SMT scheduler support improves the CPU scheduler's decision making
334 when dealing with Intel Pentium 4 chips with HyperThreading at a
335 cost of slightly increased overhead in some places. If unsure say
339 bool "Multi-core scheduler support"
340 depends on SMP && !X86_64_XEN
343 Multi-core scheduler support improves the CPU scheduler's decision
344 making when dealing with multi-core CPU chips at a cost of slightly
345 increased overhead in some places. If unsure say N here.
347 source "kernel/Kconfig.preempt"
350 bool "Non Uniform Memory Access (NUMA) Support"
351 depends on SMP && !X86_64_XEN
353 Enable NUMA (Non Uniform Memory Access) support. The kernel
354 will try to allocate memory used by a CPU on the local memory
355 controller of the CPU and add some more NUMA awareness to the kernel.
356 This code is recommended on all multiprocessor Opteron systems.
357 If the system is EM64T, you should say N unless your system is EM64T
361 bool "Old style AMD Opteron NUMA detection"
362 depends on NUMA && PCI
365 Enable K8 NUMA node topology detection. You should say Y here if
366 you have a multi processor AMD K8 system. This uses an old
367 method to read the NUMA configuration directly from the builtin
368 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
369 instead, which also takes priority if both are compiled in.
374 depends on NEED_MULTIPLE_NODES
376 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
378 config X86_64_ACPI_NUMA
379 bool "ACPI NUMA detection"
386 Enable ACPI SRAT based node topology detection.
389 bool "NUMA emulation"
392 Enable NUMA emulation. A flat machine will be split
393 into virtual nodes when booted with "numa=fake=N", where N is the
394 number of nodes. This is only useful for debugging.
396 config ARCH_DISCONTIGMEM_ENABLE
401 config ARCH_DISCONTIGMEM_DEFAULT
405 config ARCH_SPARSEMEM_ENABLE
407 depends on (NUMA || EXPERIMENTAL) && !X86_64_XEN
409 config ARCH_MEMORY_PROBE
411 depends on MEMORY_HOTPLUG
413 config ARCH_FLATMEM_ENABLE
419 config MEMORY_HOTPLUG_RESERVE
421 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
423 config HAVE_ARCH_EARLY_PFN_TO_NID
427 config OUT_OF_LINE_PFN_TO_PAGE
429 depends on DISCONTIGMEM
432 int "Maximum number of CPUs (2-256)"
435 default "16" if X86_64_XEN
438 This allows you to specify the maximum number of CPUs which this
439 kernel will support. Current maximum is 256 CPUs due to
440 APIC addressing limits. Less depending on the hardware.
442 This is purely to save memory - each supported CPU requires
443 memory in the static kernel configuration.
446 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
447 depends on SMP && HOTPLUG && EXPERIMENTAL
449 Say Y here to experiment with turning CPUs off and on. CPUs
450 can be controlled through /sys/devices/system/cpu/cpu#.
451 Say N if you want to disable CPU hotplug.
453 config ARCH_ENABLE_MEMORY_HOTPLUG
458 depends on !X86_64_XEN
461 Use the IA-PC HPET (High Precision Event Timer) to manage
462 time in preference to the PIT and RTC, if a HPET is
463 present. The HPET provides a stable time base on SMP
464 systems, unlike the TSC, but it is more expensive to access,
465 as it is off-chip. You can find the HPET spec at
466 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
468 config HPET_EMULATE_RTC
469 bool "Provide RTC interrupt"
470 depends on HPET_TIMER && RTC=y
472 # Mark as embedded because too many people got it wrong.
473 # The code disables itself when not needed.
475 bool "IOMMU support" if EMBEDDED
479 depends on PCI && !X86_64_XEN
481 Support for full DMA access of devices with 32bit memory access only
482 on systems with more than 3GB. This is usually needed for USB,
483 sound, many IDE/SATA chipsets and some other devices.
484 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
485 based IOMMU and a software bounce buffer based IOMMU used on Intel
486 systems and as fallback.
487 The code is only active when needed (enough memory and limited
488 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
492 bool "IBM Calgary IOMMU support"
494 depends on PCI && EXPERIMENTAL
496 Support for hardware IOMMUs in IBM's xSeries x366 and x460
497 systems. Needed to run systems with more than 3GB of memory
498 properly with 32-bit PCI devices that do not support DAC
499 (Double Address Cycle). Calgary also supports bus level
500 isolation, where all DMAs pass through the IOMMU. This
501 prevents them from going anywhere except their intended
502 destination. This catches hard-to-find kernel bugs and
503 mis-behaving drivers and devices that do not use the DMA-API
504 properly to set up their DMA buffers. The IOMMU can be
505 turned off at boot time with the iommu=off parameter.
506 Normally the kernel will make the right choice by itself.
509 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
510 bool "Should Calgary be enabled by default?"
512 depends on CALGARY_IOMMU
514 Should Calgary be enabled by default? if you choose 'y', Calgary
515 will be used (if it exists). If you choose 'n', Calgary will not be
516 used even if it exists. If you choose 'n' and would like to use
517 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
520 # need this always selected by IOMMU for the VIA workaround
525 bool "Machine check support" if EMBEDDED
526 depends on !X86_64_XEN
529 Include a machine check error handler to report hardware errors.
530 This version will require the mcelog utility to decode some
531 machine check error logs. See
532 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
535 bool "Intel MCE features"
536 depends on X86_MCE && X86_LOCAL_APIC
539 Additional support for intel specific MCE features such as
543 bool "AMD MCE features"
544 depends on X86_MCE && X86_LOCAL_APIC
547 Additional support for AMD specific MCE features such as
548 the DRAM Error Threshold.
551 bool "kexec system call"
552 depends on !X86_64_XEN
554 kexec is a system call that implements the ability to shutdown your
555 current kernel, and to start another kernel. It is like a reboot
556 but it is independent of the system firmware. And like a reboot
557 you can start any kernel with it, not just Linux.
559 The name comes from the similarity to the exec system call.
561 It is an ongoing process to be certain the hardware in a machine
562 is properly shutdown, so do not be surprised if this code does not
563 initially work for you. It may help to enable device hotplugging
564 support. As of this writing the exact hardware interface is
565 strongly in flux, so no good recommendation can be made.
568 bool "kernel crash dumps (EXPERIMENTAL)"
569 depends on EXPERIMENTAL
571 Generate crash dump after being started by kexec.
572 This should be normally only set in special crash dump kernels
573 which are loaded in the main kernel with kexec-tools into
574 a specially reserved region and then later executed after
575 a crash by kdump/kexec. The crash dump kernel must be compiled
576 to a memory address not used by the main kernel or BIOS using
578 For more details see Documentation/kdump/kdump.txt
580 config PHYSICAL_START
581 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
582 default "0x1000000" if CRASH_DUMP
585 This gives the physical address where the kernel is loaded. Normally
586 for regular kernels this value is 0x200000 (2MB). But in the case
587 of kexec on panic the fail safe kernel needs to run at a different
588 address than the panic-ed kernel. This option is used to set the load
589 address for kernels used to capture crash dump on being kexec'ed
590 after panic. The default value for crash dump kernels is
591 0x1000000 (16MB). This can also be set based on the "X" value as
592 specified in the "crashkernel=YM@XM" command line boot parameter
593 passed to the panic-ed kernel. Typically this parameter is set as
594 crashkernel=64M@16M. Please take a look at
595 Documentation/kdump/kdump.txt for more details about crash dumps.
597 Don't change this unless you know what you are doing.
600 bool "Enable seccomp to safely compute untrusted bytecode"
604 This kernel feature is useful for number crunching applications
605 that may need to compute untrusted bytecode during their
606 execution. By using pipes or other transports made available to
607 the process as file descriptors supporting the read/write
608 syscalls, it's possible to isolate those applications in
609 their own address space using seccomp. Once seccomp is
610 enabled via /proc/<pid>/seccomp, it cannot be disabled
611 and the task is only allowed to execute a few safe syscalls
612 defined by each seccomp mode.
614 If unsure, say Y. Only embedded should say N here.
616 config CC_STACKPROTECTOR
617 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
618 depends on EXPERIMENTAL
620 This option turns on the -fstack-protector GCC feature. This
621 feature puts, at the beginning of critical functions, a canary
622 value on the stack just before the return address, and validates
623 the value just before actually returning. Stack based buffer
624 overflows (that need to overwrite this return address) now also
625 overwrite the canary, which gets detected and the attack is then
626 neutralized via a kernel panic.
628 This feature requires gcc version 4.2 or above, or a distribution
629 gcc with the feature backported. Older versions are automatically
630 detected and for those versions, this configuration option is ignored.
632 config CC_STACKPROTECTOR_ALL
633 bool "Use stack-protector for all functions"
634 depends on CC_STACKPROTECTOR
636 Normally, GCC only inserts the canary value protection for
637 functions that use large-ish on-stack buffers. By enabling
638 this option, GCC will be asked to do this for ALL functions.
640 source kernel/Kconfig.hz
643 bool "Function reordering"
646 This option enables the toolchain to reorder functions for a more
647 optimal TLB usage. If you have pretty much any version of binutils,
648 this can increase your kernel build time by roughly one minute.
652 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
657 # Use the generic interrupt handling code in kernel/irq/:
659 config GENERIC_HARDIRQS
663 config GENERIC_IRQ_PROBE
667 # we have no ISA slots, but we do have ISA-style DMA.
672 config GENERIC_PENDING_IRQ
674 depends on GENERIC_HARDIRQS && SMP
677 menu "Power management options"
678 depends on !XEN_UNPRIVILEGED_GUEST
681 source kernel/power/Kconfig
684 source "drivers/acpi/Kconfig"
686 source "arch/x86_64/kernel/cpufreq/Kconfig"
690 menu "Bus options (PCI etc.)"
695 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
702 bool "Support mmconfig PCI config space access"
703 depends on PCI && ACPI
705 config XEN_PCIDEV_FRONTEND
706 bool "Xen PCI Frontend"
707 depends on PCI && X86_64_XEN
710 The PCI device frontend driver allows the kernel to import arbitrary
711 PCI devices from a PCI backend to support PCI driver domains.
713 config XEN_PCIDEV_FE_DEBUG
714 bool "Xen PCI Frontend Debugging"
715 depends on XEN_PCIDEV_FRONTEND
718 Enables some debug statements within the PCI Frontend.
720 source "drivers/pci/pcie/Kconfig"
722 source "drivers/pci/Kconfig"
724 source "drivers/pcmcia/Kconfig"
726 source "drivers/pci/hotplug/Kconfig"
731 menu "Executable file formats / Emulations"
733 source "fs/Kconfig.binfmt"
735 config IA32_EMULATION
736 bool "IA32 Emulation"
738 Include code to run 32-bit programs under a 64-bit kernel. You should likely
739 turn this on, unless you're 100% sure that you don't have any 32-bit programs
743 tristate "IA32 a.out support"
744 depends on IA32_EMULATION
746 Support old a.out binaries in the 32bit emulation.
750 depends on IA32_EMULATION
753 config SYSVIPC_COMPAT
755 depends on COMPAT && SYSVIPC
762 source drivers/Kconfig
764 source "drivers/firmware/Kconfig"
768 menu "Instrumentation Support"
769 depends on EXPERIMENTAL
771 source "arch/x86_64/oprofile/Kconfig"
774 bool "Kprobes (EXPERIMENTAL)"
775 depends on KALLSYMS && EXPERIMENTAL && MODULES
777 Kprobes allows you to trap at almost any kernel address and
778 execute a callback function. register_kprobe() establishes
779 a probepoint and specifies the callback. Kprobes is useful
780 for kernel debugging, non-intrusive instrumentation and testing.
781 If in doubt, say "N".
784 source "arch/x86_64/Kconfig.debug"
786 source "kernel/vserver/Kconfig"
788 source "security/Kconfig"
790 source "crypto/Kconfig"
792 source "drivers/xen/Kconfig"