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)
413 config ARCH_MEMORY_PROBE
415 depends on MEMORY_HOTPLUG
417 config ARCH_FLATMEM_ENABLE
423 config MEMORY_HOTPLUG_RESERVE
425 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
427 config HAVE_ARCH_EARLY_PFN_TO_NID
431 config OUT_OF_LINE_PFN_TO_PAGE
433 depends on DISCONTIGMEM
436 int "Maximum number of CPUs (2-255)"
441 This allows you to specify the maximum number of CPUs which this
442 kernel will support. Current maximum is 255 CPUs due to
443 APIC addressing limits. Less depending on the hardware.
445 This is purely to save memory - each supported CPU requires
446 memory in the static kernel configuration.
448 config PHYSICAL_ALIGN
453 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
454 depends on SMP && HOTPLUG && EXPERIMENTAL
456 Say Y here to experiment with turning CPUs off and on. CPUs
457 can be controlled through /sys/devices/system/cpu/cpu#.
458 This is also required for suspend/hibernation on SMP systems.
460 Say N if you want to disable CPU hotplug and don't need to
463 config ARCH_ENABLE_MEMORY_HOTPLUG
470 Use the IA-PC HPET (High Precision Event Timer) to manage
471 time in preference to the PIT and RTC, if a HPET is
472 present. The HPET provides a stable time base on SMP
473 systems, unlike the TSC, but it is more expensive to access,
474 as it is off-chip. You can find the HPET spec at
475 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
477 config HPET_EMULATE_RTC
478 bool "Provide RTC interrupt"
479 depends on HPET_TIMER && RTC=y
481 # Mark as embedded because too many people got it wrong.
482 # The code disables itself when not needed.
484 bool "IOMMU support" if EMBEDDED
490 Support for full DMA access of devices with 32bit memory access only
491 on systems with more than 3GB. This is usually needed for USB,
492 sound, many IDE/SATA chipsets and some other devices.
493 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
494 based hardware IOMMU and a software bounce buffer based IOMMU used
495 on Intel systems and as fallback.
496 The code is only active when needed (enough memory and limited
497 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
501 bool "IBM Calgary IOMMU support"
503 depends on PCI && EXPERIMENTAL
505 Support for hardware IOMMUs in IBM's xSeries x366 and x460
506 systems. Needed to run systems with more than 3GB of memory
507 properly with 32-bit PCI devices that do not support DAC
508 (Double Address Cycle). Calgary also supports bus level
509 isolation, where all DMAs pass through the IOMMU. This
510 prevents them from going anywhere except their intended
511 destination. This catches hard-to-find kernel bugs and
512 mis-behaving drivers and devices that do not use the DMA-API
513 properly to set up their DMA buffers. The IOMMU can be
514 turned off at boot time with the iommu=off parameter.
515 Normally the kernel will make the right choice by itself.
518 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
519 bool "Should Calgary be enabled by default?"
521 depends on CALGARY_IOMMU
523 Should Calgary be enabled by default? if you choose 'y', Calgary
524 will be used (if it exists). If you choose 'n', Calgary will not be
525 used even if it exists. If you choose 'n' and would like to use
526 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
529 # need this always selected by IOMMU for the VIA workaround
533 Support for software bounce buffers used on x86-64 systems
534 which don't have a hardware IOMMU (e.g. the current generation
535 of Intel's x86-64 CPUs). Using this PCI devices which can only
536 access 32-bits of memory can be used on systems with more than
537 3 GB of memory. If unsure, say Y.
540 bool "Machine check support" if EMBEDDED
543 Include a machine check error handler to report hardware errors.
544 This version will require the mcelog utility to decode some
545 machine check error logs. See
546 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
549 bool "Intel MCE features"
550 depends on X86_MCE && X86_LOCAL_APIC
553 Additional support for intel specific MCE features such as
557 bool "AMD MCE features"
558 depends on X86_MCE && X86_LOCAL_APIC
561 Additional support for AMD specific MCE features such as
562 the DRAM Error Threshold.
565 bool "kexec system call"
567 kexec is a system call that implements the ability to shutdown your
568 current kernel, and to start another kernel. It is like a reboot
569 but it is independent of the system firmware. And like a reboot
570 you can start any kernel with it, not just Linux.
572 The name comes from the similarity to the exec system call.
574 It is an ongoing process to be certain the hardware in a machine
575 is properly shutdown, so do not be surprised if this code does not
576 initially work for you. It may help to enable device hotplugging
577 support. As of this writing the exact hardware interface is
578 strongly in flux, so no good recommendation can be made.
581 bool "kernel crash dumps (EXPERIMENTAL)"
582 depends on EXPERIMENTAL
584 Generate crash dump after being started by kexec.
585 This should be normally only set in special crash dump kernels
586 which are loaded in the main kernel with kexec-tools into
587 a specially reserved region and then later executed after
588 a crash by kdump/kexec. The crash dump kernel must be compiled
589 to a memory address not used by the main kernel or BIOS using
591 For more details see Documentation/kdump/kdump.txt
594 bool "Build a relocatable kernel(EXPERIMENTAL)"
595 depends on EXPERIMENTAL
597 Builds a relocatable kernel. This enables loading and running
598 a kernel binary from a different physical address than it has
601 One use is for the kexec on panic case where the recovery kernel
602 must live at a different physical address than the primary
605 Note: If CONFIG_RELOCATABLE=y, then kernel run from the address
606 it has been loaded at and compile time physical address
607 (CONFIG_PHYSICAL_START) is ignored.
609 config PHYSICAL_START
610 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
613 This gives the physical address where the kernel is loaded. It
614 should be aligned to 2MB boundary.
616 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
617 bzImage will decompress itself to above physical address and
618 run from there. Otherwise, bzImage will run from the address where
619 it has been loaded by the boot loader and will ignore above physical
622 In normal kdump cases one does not have to set/change this option
623 as now bzImage can be compiled as a completely relocatable image
624 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
625 address. This option is mainly useful for the folks who don't want
626 to use a bzImage for capturing the crash dump and want to use a
629 So if you are using bzImage for capturing the crash dump, leave
630 the value here unchanged to 0x200000 and set CONFIG_RELOCATABLE=y.
631 Otherwise if you plan to use vmlinux for capturing the crash dump
632 change this value to start of the reserved region (Typically 16MB
633 0x1000000). In other words, it can be set based on the "X" value as
634 specified in the "crashkernel=YM@XM" command line boot parameter
635 passed to the panic-ed kernel. Typically this parameter is set as
636 crashkernel=64M@16M. Please take a look at
637 Documentation/kdump/kdump.txt for more details about crash dumps.
639 Usage of bzImage for capturing the crash dump is advantageous as
640 one does not have to build two kernels. Same kernel can be used
641 as production kernel and capture kernel.
643 Don't change this unless you know what you are doing.
646 bool "Enable seccomp to safely compute untrusted bytecode"
650 This kernel feature is useful for number crunching applications
651 that may need to compute untrusted bytecode during their
652 execution. By using pipes or other transports made available to
653 the process as file descriptors supporting the read/write
654 syscalls, it's possible to isolate those applications in
655 their own address space using seccomp. Once seccomp is
656 enabled via /proc/<pid>/seccomp, it cannot be disabled
657 and the task is only allowed to execute a few safe syscalls
658 defined by each seccomp mode.
660 If unsure, say Y. Only embedded should say N here.
662 config CC_STACKPROTECTOR
663 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
664 depends on EXPERIMENTAL
666 This option turns on the -fstack-protector GCC feature. This
667 feature puts, at the beginning of critical functions, a canary
668 value on the stack just before the return address, and validates
669 the value just before actually returning. Stack based buffer
670 overflows (that need to overwrite this return address) now also
671 overwrite the canary, which gets detected and the attack is then
672 neutralized via a kernel panic.
674 This feature requires gcc version 4.2 or above, or a distribution
675 gcc with the feature backported. Older versions are automatically
676 detected and for those versions, this configuration option is ignored.
678 config CC_STACKPROTECTOR_ALL
679 bool "Use stack-protector for all functions"
680 depends on CC_STACKPROTECTOR
682 Normally, GCC only inserts the canary value protection for
683 functions that use large-ish on-stack buffers. By enabling
684 this option, GCC will be asked to do this for ALL functions.
686 source kernel/Kconfig.hz
690 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
695 # Use the generic interrupt handling code in kernel/irq/:
697 config GENERIC_HARDIRQS
701 config GENERIC_IRQ_PROBE
705 # we have no ISA slots, but we do have ISA-style DMA.
710 config GENERIC_PENDING_IRQ
712 depends on GENERIC_HARDIRQS && SMP
715 menu "Power management options"
717 source kernel/power/Kconfig
719 source "drivers/acpi/Kconfig"
721 source "arch/x86/kernel/cpufreq/Kconfig"
725 menu "Bus options (PCI etc.)"
729 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
731 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
738 bool "Support mmconfig PCI config space access"
739 depends on PCI && ACPI
746 source "drivers/pci/pcie/Kconfig"
748 source "drivers/pci/Kconfig"
750 source "drivers/pcmcia/Kconfig"
752 source "drivers/pci/hotplug/Kconfig"
757 menu "Executable file formats / Emulations"
759 source "fs/Kconfig.binfmt"
761 config IA32_EMULATION
762 bool "IA32 Emulation"
764 Include code to run 32-bit programs under a 64-bit kernel. You should likely
765 turn this on, unless you're 100% sure that you don't have any 32-bit programs
769 tristate "IA32 a.out support"
770 depends on IA32_EMULATION
772 Support old a.out binaries in the 32bit emulation.
776 depends on IA32_EMULATION
779 config COMPAT_FOR_U64_ALIGNMENT
782 config SYSVIPC_COMPAT
784 depends on COMPAT && SYSVIPC
791 source drivers/Kconfig
793 source "drivers/firmware/Kconfig"
797 menu "Instrumentation Support"
798 depends on EXPERIMENTAL
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"