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
39 config SEMAPHORE_SLEEPERS
57 config RWSEM_GENERIC_SPINLOCK
61 config RWSEM_XCHGADD_ALGORITHM
64 config GENERIC_HWEIGHT
68 config GENERIC_CALIBRATE_DELAY
80 config GENERIC_ISA_DMA
88 config ARCH_MAY_HAVE_PC_FDC
92 config ARCH_POPULATES_NODE_MAP
108 config ARCH_HAS_ILOG2_U32
112 config ARCH_HAS_ILOG2_U64
116 source "init/Kconfig"
119 menu "Processor type and features"
122 prompt "Subarchitecture Type"
128 Choose this option if your computer is a standard PC or compatible.
131 bool "Support for ScaleMP vSMP"
134 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
135 supposed to run on these EM64T-based machines. Only choose this option
136 if you have one of these machines.
141 prompt "Processor family"
145 bool "AMD-Opteron/Athlon64"
147 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
150 bool "Intel P4 / older Netburst based Xeon"
152 Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
153 with Intel Extended Memory 64 Technology(EM64T). For details see
154 <http://www.intel.com/technology/64bitextensions/>.
155 Note the the latest Xeons (Xeon 51xx and 53xx) are not based on the
156 Netburst core and shouldn't use this option. You can distingush them
157 using the cpu family field
158 in /proc/cpuinfo. Family 15 is a older Xeon, Family 6 a newer one
159 (this rule only applies to system that support EM64T)
162 bool "Intel Core2 / newer Xeon"
164 Optimize for Intel Core2 and newer Xeons (51xx)
165 You can distingush the newer Xeons from the older ones using
166 the cpu family field in /proc/cpuinfo. 15 is a older Xeon
167 (use CONFIG_MPSC then), 6 is a newer one. This rule only
168 applies to CPUs that support EM64T.
171 bool "Generic-x86-64"
174 Run equally well on all x86-64 CPUs.
179 # Define implied options from the CPU selection here
181 config X86_L1_CACHE_BYTES
183 default "128" if GENERIC_CPU || MPSC
184 default "64" if MK8 || MCORE2
186 config X86_L1_CACHE_SHIFT
188 default "7" if GENERIC_CPU || MPSC
189 default "6" if MK8 || MCORE2
191 config X86_INTERNODE_CACHE_BYTES
193 default "4096" if X86_VSMP
194 default X86_L1_CACHE_BYTES if !X86_VSMP
205 tristate "/dev/cpu/microcode - Intel CPU microcode support"
208 If you say Y here the 'File systems' section, you will be
209 able to update the microcode on Intel processors. You will
210 obviously need the actual microcode binary data itself which is
211 not shipped with the Linux kernel.
213 For latest news and information on obtaining all the required
214 ingredients for this driver, check:
215 <http://www.urbanmyth.org/microcode/>.
217 To compile this driver as a module, choose M here: the
218 module will be called microcode.
219 If you use modprobe or kmod you may also want to add the line
220 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
222 config MICROCODE_OLD_INTERFACE
228 tristate "/dev/cpu/*/msr - Model-specific register support"
230 This device gives privileged processes access to the x86
231 Model-Specific Registers (MSRs). It is a character device with
232 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
233 MSR accesses are directed to a specific CPU on multi-processor
237 tristate "/dev/cpu/*/cpuid - CPU information support"
239 This device gives processes access to the x86 CPUID instruction to
240 be executed on a specific processor. It is a character device
241 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
246 depends on SMP && !MK8
249 config MATH_EMULATION
262 config X86_LOCAL_APIC
267 bool "MTRR (Memory Type Range Register) support"
269 On Intel P6 family processors (Pentium Pro, Pentium II and later)
270 the Memory Type Range Registers (MTRRs) may be used to control
271 processor access to memory ranges. This is most useful if you have
272 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
273 allows bus write transfers to be combined into a larger transfer
274 before bursting over the PCI/AGP bus. This can increase performance
275 of image write operations 2.5 times or more. Saying Y here creates a
276 /proc/mtrr file which may be used to manipulate your processor's
277 MTRRs. Typically the X server should use this.
279 This code has a reasonably generic interface so that similar
280 control registers on other processors can be easily supported
283 Saying Y here also fixes a problem with buggy SMP BIOSes which only
284 set the MTRRs for the boot CPU and not for the secondary CPUs. This
285 can lead to all sorts of problems, so it's good to say Y here.
287 Just say Y here, all x86-64 machines support MTRRs.
289 See <file:Documentation/mtrr.txt> for more information.
292 bool "Symmetric multi-processing support"
294 This enables support for systems with more than one CPU. If you have
295 a system with only one CPU, like most personal computers, say N. If
296 you have a system with more than one CPU, say Y.
298 If you say N here, the kernel will run on single and multiprocessor
299 machines, but will use only one CPU of a multiprocessor machine. If
300 you say Y here, the kernel will run on many, but not all,
301 singleprocessor machines. On a singleprocessor machine, the kernel
302 will run faster if you say N here.
304 If you don't know what to do here, say N.
307 bool "SMT (Hyperthreading) scheduler support"
311 SMT scheduler support improves the CPU scheduler's decision making
312 when dealing with Intel Pentium 4 chips with HyperThreading at a
313 cost of slightly increased overhead in some places. If unsure say
317 bool "Multi-core scheduler support"
321 Multi-core scheduler support improves the CPU scheduler's decision
322 making when dealing with multi-core CPU chips at a cost of slightly
323 increased overhead in some places. If unsure say N here.
325 source "kernel/Kconfig.preempt"
328 bool "Non Uniform Memory Access (NUMA) Support"
331 Enable NUMA (Non Uniform Memory Access) support. The kernel
332 will try to allocate memory used by a CPU on the local memory
333 controller of the CPU and add some more NUMA awareness to the kernel.
334 This code is recommended on all multiprocessor Opteron systems.
335 If the system is EM64T, you should say N unless your system is EM64T
339 bool "Old style AMD Opteron NUMA detection"
340 depends on NUMA && PCI
343 Enable K8 NUMA node topology detection. You should say Y here if
344 you have a multi processor AMD K8 system. This uses an old
345 method to read the NUMA configuration directly from the builtin
346 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
347 instead, which also takes priority if both are compiled in.
352 depends on NEED_MULTIPLE_NODES
354 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
356 config X86_64_ACPI_NUMA
357 bool "ACPI NUMA detection"
364 Enable ACPI SRAT based node topology detection.
367 bool "NUMA emulation"
370 Enable NUMA emulation. A flat machine will be split
371 into virtual nodes when booted with "numa=fake=N", where N is the
372 number of nodes. This is only useful for debugging.
374 config ARCH_DISCONTIGMEM_ENABLE
379 config ARCH_DISCONTIGMEM_DEFAULT
383 config ARCH_SPARSEMEM_ENABLE
385 depends on (NUMA || EXPERIMENTAL)
387 config ARCH_MEMORY_PROBE
389 depends on MEMORY_HOTPLUG
391 config ARCH_FLATMEM_ENABLE
397 config MEMORY_HOTPLUG_RESERVE
399 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
401 config HAVE_ARCH_EARLY_PFN_TO_NID
405 config OUT_OF_LINE_PFN_TO_PAGE
407 depends on DISCONTIGMEM
410 int "Maximum number of CPUs (2-256)"
415 This allows you to specify the maximum number of CPUs which this
416 kernel will support. Current maximum is 256 CPUs due to
417 APIC addressing limits. Less depending on the hardware.
419 This is purely to save memory - each supported CPU requires
420 memory in the static kernel configuration.
423 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
424 depends on SMP && HOTPLUG && EXPERIMENTAL
426 Say Y here to experiment with turning CPUs off and on. CPUs
427 can be controlled through /sys/devices/system/cpu/cpu#.
428 Say N if you want to disable CPU hotplug.
430 config ARCH_ENABLE_MEMORY_HOTPLUG
437 Use the IA-PC HPET (High Precision Event Timer) to manage
438 time in preference to the PIT and RTC, if a HPET is
439 present. The HPET provides a stable time base on SMP
440 systems, unlike the TSC, but it is more expensive to access,
441 as it is off-chip. You can find the HPET spec at
442 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
444 config HPET_EMULATE_RTC
445 bool "Provide RTC interrupt"
446 depends on HPET_TIMER && RTC=y
448 # Mark as embedded because too many people got it wrong.
449 # The code disables itself when not needed.
451 bool "IOMMU support" if EMBEDDED
457 Support for full DMA access of devices with 32bit memory access only
458 on systems with more than 3GB. This is usually needed for USB,
459 sound, many IDE/SATA chipsets and some other devices.
460 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
461 based IOMMU and a software bounce buffer based IOMMU used on Intel
462 systems and as fallback.
463 The code is only active when needed (enough memory and limited
464 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
468 bool "IBM Calgary IOMMU support"
470 depends on PCI && EXPERIMENTAL
472 Support for hardware IOMMUs in IBM's xSeries x366 and x460
473 systems. Needed to run systems with more than 3GB of memory
474 properly with 32-bit PCI devices that do not support DAC
475 (Double Address Cycle). Calgary also supports bus level
476 isolation, where all DMAs pass through the IOMMU. This
477 prevents them from going anywhere except their intended
478 destination. This catches hard-to-find kernel bugs and
479 mis-behaving drivers and devices that do not use the DMA-API
480 properly to set up their DMA buffers. The IOMMU can be
481 turned off at boot time with the iommu=off parameter.
482 Normally the kernel will make the right choice by itself.
485 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
486 bool "Should Calgary be enabled by default?"
488 depends on CALGARY_IOMMU
490 Should Calgary be enabled by default? if you choose 'y', Calgary
491 will be used (if it exists). If you choose 'n', Calgary will not be
492 used even if it exists. If you choose 'n' and would like to use
493 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
496 # need this always selected by IOMMU for the VIA workaround
501 bool "Machine check support" if EMBEDDED
504 Include a machine check error handler to report hardware errors.
505 This version will require the mcelog utility to decode some
506 machine check error logs. See
507 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
510 bool "Intel MCE features"
511 depends on X86_MCE && X86_LOCAL_APIC
514 Additional support for intel specific MCE features such as
518 bool "AMD MCE features"
519 depends on X86_MCE && X86_LOCAL_APIC
522 Additional support for AMD specific MCE features such as
523 the DRAM Error Threshold.
526 bool "kexec system call"
528 kexec is a system call that implements the ability to shutdown your
529 current kernel, and to start another kernel. It is like a reboot
530 but it is independent of the system firmware. And like a reboot
531 you can start any kernel with it, not just Linux.
533 The name comes from the similarity to the exec system call.
535 It is an ongoing process to be certain the hardware in a machine
536 is properly shutdown, so do not be surprised if this code does not
537 initially work for you. It may help to enable device hotplugging
538 support. As of this writing the exact hardware interface is
539 strongly in flux, so no good recommendation can be made.
542 bool "kernel crash dumps (EXPERIMENTAL)"
543 depends on EXPERIMENTAL
545 Generate crash dump after being started by kexec.
546 This should be normally only set in special crash dump kernels
547 which are loaded in the main kernel with kexec-tools into
548 a specially reserved region and then later executed after
549 a crash by kdump/kexec. The crash dump kernel must be compiled
550 to a memory address not used by the main kernel or BIOS using
552 For more details see Documentation/kdump/kdump.txt
554 config PHYSICAL_START
555 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
556 default "0x1000000" if CRASH_DUMP
559 This gives the physical address where the kernel is loaded. Normally
560 for regular kernels this value is 0x200000 (2MB). But in the case
561 of kexec on panic the fail safe kernel needs to run at a different
562 address than the panic-ed kernel. This option is used to set the load
563 address for kernels used to capture crash dump on being kexec'ed
564 after panic. The default value for crash dump kernels is
565 0x1000000 (16MB). This can also be set based on the "X" value as
566 specified in the "crashkernel=YM@XM" command line boot parameter
567 passed to the panic-ed kernel. Typically this parameter is set as
568 crashkernel=64M@16M. Please take a look at
569 Documentation/kdump/kdump.txt for more details about crash dumps.
571 Don't change this unless you know what you are doing.
574 bool "Enable seccomp to safely compute untrusted bytecode"
578 This kernel feature is useful for number crunching applications
579 that may need to compute untrusted bytecode during their
580 execution. By using pipes or other transports made available to
581 the process as file descriptors supporting the read/write
582 syscalls, it's possible to isolate those applications in
583 their own address space using seccomp. Once seccomp is
584 enabled via /proc/<pid>/seccomp, it cannot be disabled
585 and the task is only allowed to execute a few safe syscalls
586 defined by each seccomp mode.
588 If unsure, say Y. Only embedded should say N here.
590 config CC_STACKPROTECTOR
591 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
592 depends on EXPERIMENTAL
594 This option turns on the -fstack-protector GCC feature. This
595 feature puts, at the beginning of critical functions, a canary
596 value on the stack just before the return address, and validates
597 the value just before actually returning. Stack based buffer
598 overflows (that need to overwrite this return address) now also
599 overwrite the canary, which gets detected and the attack is then
600 neutralized via a kernel panic.
602 This feature requires gcc version 4.2 or above, or a distribution
603 gcc with the feature backported. Older versions are automatically
604 detected and for those versions, this configuration option is ignored.
606 config CC_STACKPROTECTOR_ALL
607 bool "Use stack-protector for all functions"
608 depends on CC_STACKPROTECTOR
610 Normally, GCC only inserts the canary value protection for
611 functions that use large-ish on-stack buffers. By enabling
612 this option, GCC will be asked to do this for ALL functions.
614 source kernel/Kconfig.hz
617 bool "Function reordering"
620 This option enables the toolchain to reorder functions for a more
621 optimal TLB usage. If you have pretty much any version of binutils,
622 this can increase your kernel build time by roughly one minute.
626 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
631 # Use the generic interrupt handling code in kernel/irq/:
633 config GENERIC_HARDIRQS
637 config GENERIC_IRQ_PROBE
641 # we have no ISA slots, but we do have ISA-style DMA.
646 config GENERIC_PENDING_IRQ
648 depends on GENERIC_HARDIRQS && SMP
651 menu "Power management options"
653 source kernel/power/Kconfig
655 source "drivers/acpi/Kconfig"
657 source "arch/x86_64/kernel/cpufreq/Kconfig"
661 menu "Bus options (PCI etc.)"
666 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
673 bool "Support mmconfig PCI config space access"
674 depends on PCI && ACPI
676 source "drivers/pci/pcie/Kconfig"
678 source "drivers/pci/Kconfig"
680 source "drivers/pcmcia/Kconfig"
682 source "drivers/pci/hotplug/Kconfig"
687 menu "Executable file formats / Emulations"
689 source "fs/Kconfig.binfmt"
691 config IA32_EMULATION
692 bool "IA32 Emulation"
694 Include code to run 32-bit programs under a 64-bit kernel. You should likely
695 turn this on, unless you're 100% sure that you don't have any 32-bit programs
699 tristate "IA32 a.out support"
700 depends on IA32_EMULATION
702 Support old a.out binaries in the 32bit emulation.
706 depends on IA32_EMULATION
709 config SYSVIPC_COMPAT
711 depends on COMPAT && SYSVIPC
718 source drivers/Kconfig
720 source "drivers/firmware/Kconfig"
724 menu "Instrumentation Support"
725 depends on EXPERIMENTAL
727 source "arch/x86_64/oprofile/Kconfig"
730 bool "Kprobes (EXPERIMENTAL)"
731 depends on KALLSYMS && EXPERIMENTAL && MODULES
733 Kprobes allows you to trap at almost any kernel address and
734 execute a callback function. register_kprobe() establishes
735 a probepoint and specifies the callback. Kprobes is useful
736 for kernel debugging, non-intrusive instrumentation and testing.
737 If in doubt, say "N".
740 source "arch/x86_64/Kconfig.debug"
742 source "security/Kconfig"
744 source "crypto/Kconfig"