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
43 config LOCKDEP_SUPPORT
47 config STACKTRACE_SUPPORT
51 config SEMAPHORE_SLEEPERS
69 config RWSEM_GENERIC_SPINLOCK
73 config RWSEM_XCHGADD_ALGORITHM
76 config GENERIC_HWEIGHT
80 config GENERIC_CALIBRATE_DELAY
92 config GENERIC_ISA_DMA
100 config ARCH_MAY_HAVE_PC_FDC
104 config ARCH_POPULATES_NODE_MAP
120 config ARCH_HAS_ILOG2_U32
124 config ARCH_HAS_ILOG2_U64
128 source "init/Kconfig"
131 menu "Processor type and features"
134 prompt "Subarchitecture Type"
140 Choose this option if your computer is a standard PC or compatible.
143 bool "Support for ScaleMP vSMP"
146 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
147 supposed to run on these EM64T-based machines. Only choose this option
148 if you have one of these machines.
153 prompt "Processor family"
157 bool "AMD-Opteron/Athlon64"
159 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
162 bool "Intel P4 / older Netburst based Xeon"
164 Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
165 with Intel Extended Memory 64 Technology(EM64T). For details see
166 <http://www.intel.com/technology/64bitextensions/>.
167 Note that the latest Xeons (Xeon 51xx and 53xx) are not based on the
168 Netburst core and shouldn't use this option. You can distinguish them
169 using the cpu family field
170 in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one
171 (this rule only applies to systems that support EM64T)
174 bool "Intel Core2 / newer Xeon"
176 Optimize for Intel Core2 and newer Xeons (51xx)
177 You can distinguish the newer Xeons from the older ones using
178 the cpu family field in /proc/cpuinfo. 15 is an older Xeon
179 (use CONFIG_MPSC then), 6 is a newer one. This rule only
180 applies to CPUs that support EM64T.
183 bool "Generic-x86-64"
186 Run equally well on all x86-64 CPUs.
191 # Define implied options from the CPU selection here
193 config X86_L1_CACHE_BYTES
195 default "128" if GENERIC_CPU || MPSC
196 default "64" if MK8 || MCORE2
198 config X86_L1_CACHE_SHIFT
200 default "7" if GENERIC_CPU || MPSC
201 default "6" if MK8 || MCORE2
203 config X86_INTERNODE_CACHE_BYTES
205 default "4096" if X86_VSMP
206 default X86_L1_CACHE_BYTES if !X86_VSMP
217 tristate "/dev/cpu/microcode - Intel CPU microcode support"
220 If you say Y here the 'File systems' section, you will be
221 able to update the microcode on Intel processors. You will
222 obviously need the actual microcode binary data itself which is
223 not shipped with the Linux kernel.
225 For latest news and information on obtaining all the required
226 ingredients for this driver, check:
227 <http://www.urbanmyth.org/microcode/>.
229 To compile this driver as a module, choose M here: the
230 module will be called microcode.
231 If you use modprobe or kmod you may also want to add the line
232 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
234 config MICROCODE_OLD_INTERFACE
240 tristate "/dev/cpu/*/msr - Model-specific register support"
242 This device gives privileged processes access to the x86
243 Model-Specific Registers (MSRs). It is a character device with
244 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
245 MSR accesses are directed to a specific CPU on multi-processor
249 tristate "/dev/cpu/*/cpuid - CPU information support"
251 This device gives processes access to the x86 CPUID instruction to
252 be executed on a specific processor. It is a character device
253 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
258 depends on SMP && !MK8
261 config MATH_EMULATION
274 config X86_LOCAL_APIC
279 bool "MTRR (Memory Type Range Register) support"
281 On Intel P6 family processors (Pentium Pro, Pentium II and later)
282 the Memory Type Range Registers (MTRRs) may be used to control
283 processor access to memory ranges. This is most useful if you have
284 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
285 allows bus write transfers to be combined into a larger transfer
286 before bursting over the PCI/AGP bus. This can increase performance
287 of image write operations 2.5 times or more. Saying Y here creates a
288 /proc/mtrr file which may be used to manipulate your processor's
289 MTRRs. Typically the X server should use this.
291 This code has a reasonably generic interface so that similar
292 control registers on other processors can be easily supported
295 Saying Y here also fixes a problem with buggy SMP BIOSes which only
296 set the MTRRs for the boot CPU and not for the secondary CPUs. This
297 can lead to all sorts of problems, so it's good to say Y here.
299 Just say Y here, all x86-64 machines support MTRRs.
301 See <file:Documentation/mtrr.txt> for more information.
304 bool "Symmetric multi-processing support"
306 This enables support for systems with more than one CPU. If you have
307 a system with only one CPU, like most personal computers, say N. If
308 you have a system with more than one CPU, say Y.
310 If you say N here, the kernel will run on single and multiprocessor
311 machines, but will use only one CPU of a multiprocessor machine. If
312 you say Y here, the kernel will run on many, but not all,
313 singleprocessor machines. On a singleprocessor machine, the kernel
314 will run faster if you say N here.
316 If you don't know what to do here, say N.
319 bool "SMT (Hyperthreading) scheduler support"
323 SMT scheduler support improves the CPU scheduler's decision making
324 when dealing with Intel Pentium 4 chips with HyperThreading at a
325 cost of slightly increased overhead in some places. If unsure say
329 bool "Multi-core scheduler support"
333 Multi-core scheduler support improves the CPU scheduler's decision
334 making when dealing with multi-core CPU chips at a cost of slightly
335 increased overhead in some places. If unsure say N here.
337 source "kernel/Kconfig.preempt"
340 bool "Non Uniform Memory Access (NUMA) Support"
343 Enable NUMA (Non Uniform Memory Access) support. The kernel
344 will try to allocate memory used by a CPU on the local memory
345 controller of the CPU and add some more NUMA awareness to the kernel.
346 This code is recommended on all multiprocessor Opteron systems.
347 If the system is EM64T, you should say N unless your system is EM64T
351 bool "Old style AMD Opteron NUMA detection"
352 depends on NUMA && PCI
355 Enable K8 NUMA node topology detection. You should say Y here if
356 you have a multi processor AMD K8 system. This uses an old
357 method to read the NUMA configuration directly from the builtin
358 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
359 instead, which also takes priority if both are compiled in.
364 depends on NEED_MULTIPLE_NODES
366 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
368 config X86_64_ACPI_NUMA
369 bool "ACPI NUMA detection"
376 Enable ACPI SRAT based node topology detection.
379 bool "NUMA emulation"
382 Enable NUMA emulation. A flat machine will be split
383 into virtual nodes when booted with "numa=fake=N", where N is the
384 number of nodes. This is only useful for debugging.
386 config ARCH_DISCONTIGMEM_ENABLE
391 config ARCH_DISCONTIGMEM_DEFAULT
395 config ARCH_SPARSEMEM_ENABLE
397 depends on (NUMA || EXPERIMENTAL)
399 config ARCH_MEMORY_PROBE
401 depends on MEMORY_HOTPLUG
403 config ARCH_FLATMEM_ENABLE
409 config MEMORY_HOTPLUG_RESERVE
411 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
413 config HAVE_ARCH_EARLY_PFN_TO_NID
417 config OUT_OF_LINE_PFN_TO_PAGE
419 depends on DISCONTIGMEM
422 int "Maximum number of CPUs (2-255)"
427 This allows you to specify the maximum number of CPUs which this
428 kernel will support. Current maximum is 255 CPUs due to
429 APIC addressing limits. Less depending on the hardware.
431 This is purely to save memory - each supported CPU requires
432 memory in the static kernel configuration.
434 config PHYSICAL_ALIGN
439 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
440 depends on SMP && HOTPLUG && EXPERIMENTAL
442 Say Y here to experiment with turning CPUs off and on. CPUs
443 can be controlled through /sys/devices/system/cpu/cpu#.
444 This is also required for suspend/hibernation on SMP systems.
446 Say N if you want to disable CPU hotplug and don't need to
449 config ARCH_ENABLE_MEMORY_HOTPLUG
456 Use the IA-PC HPET (High Precision Event Timer) to manage
457 time in preference to the PIT and RTC, if a HPET is
458 present. The HPET provides a stable time base on SMP
459 systems, unlike the TSC, but it is more expensive to access,
460 as it is off-chip. You can find the HPET spec at
461 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
463 config HPET_EMULATE_RTC
464 bool "Provide RTC interrupt"
465 depends on HPET_TIMER && RTC=y
467 # Mark as embedded because too many people got it wrong.
468 # The code disables itself when not needed.
470 bool "IOMMU support" if EMBEDDED
476 Support for full DMA access of devices with 32bit memory access only
477 on systems with more than 3GB. This is usually needed for USB,
478 sound, many IDE/SATA chipsets and some other devices.
479 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
480 based hardware IOMMU and a software bounce buffer based IOMMU used
481 on Intel systems and as fallback.
482 The code is only active when needed (enough memory and limited
483 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
487 bool "IBM Calgary IOMMU support"
489 depends on PCI && EXPERIMENTAL
491 Support for hardware IOMMUs in IBM's xSeries x366 and x460
492 systems. Needed to run systems with more than 3GB of memory
493 properly with 32-bit PCI devices that do not support DAC
494 (Double Address Cycle). Calgary also supports bus level
495 isolation, where all DMAs pass through the IOMMU. This
496 prevents them from going anywhere except their intended
497 destination. This catches hard-to-find kernel bugs and
498 mis-behaving drivers and devices that do not use the DMA-API
499 properly to set up their DMA buffers. The IOMMU can be
500 turned off at boot time with the iommu=off parameter.
501 Normally the kernel will make the right choice by itself.
504 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
505 bool "Should Calgary be enabled by default?"
507 depends on CALGARY_IOMMU
509 Should Calgary be enabled by default? if you choose 'y', Calgary
510 will be used (if it exists). If you choose 'n', Calgary will not be
511 used even if it exists. If you choose 'n' and would like to use
512 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
515 # need this always selected by IOMMU for the VIA workaround
519 Support for software bounce buffers used on x86-64 systems
520 which don't have a hardware IOMMU (e.g. the current generation
521 of Intel's x86-64 CPUs). Using this PCI devices which can only
522 access 32-bits of memory can be used on systems with more than
523 3 GB of memory. If unsure, say Y.
526 bool "Machine check support" if EMBEDDED
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"
553 kexec is a system call that implements the ability to shutdown your
554 current kernel, and to start another kernel. It is like a reboot
555 but it is independent of the system firmware. And like a reboot
556 you can start any kernel with it, not just Linux.
558 The name comes from the similarity to the exec system call.
560 It is an ongoing process to be certain the hardware in a machine
561 is properly shutdown, so do not be surprised if this code does not
562 initially work for you. It may help to enable device hotplugging
563 support. As of this writing the exact hardware interface is
564 strongly in flux, so no good recommendation can be made.
567 bool "kernel crash dumps (EXPERIMENTAL)"
568 depends on EXPERIMENTAL
570 Generate crash dump after being started by kexec.
571 This should be normally only set in special crash dump kernels
572 which are loaded in the main kernel with kexec-tools into
573 a specially reserved region and then later executed after
574 a crash by kdump/kexec. The crash dump kernel must be compiled
575 to a memory address not used by the main kernel or BIOS using
577 For more details see Documentation/kdump/kdump.txt
580 bool "Build a relocatable kernel(EXPERIMENTAL)"
581 depends on EXPERIMENTAL
583 Builds a relocatable kernel. This enables loading and running
584 a kernel binary from a different physical address than it has
587 One use is for the kexec on panic case where the recovery kernel
588 must live at a different physical address than the primary
591 Note: If CONFIG_RELOCATABLE=y, then kernel run from the address
592 it has been loaded at and compile time physical address
593 (CONFIG_PHYSICAL_START) is ignored.
595 config PHYSICAL_START
596 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
599 This gives the physical address where the kernel is loaded. It
600 should be aligned to 2MB boundary.
602 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
603 bzImage will decompress itself to above physical address and
604 run from there. Otherwise, bzImage will run from the address where
605 it has been loaded by the boot loader and will ignore above physical
608 In normal kdump cases one does not have to set/change this option
609 as now bzImage can be compiled as a completely relocatable image
610 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
611 address. This option is mainly useful for the folks who don't want
612 to use a bzImage for capturing the crash dump and want to use a
615 So if you are using bzImage for capturing the crash dump, leave
616 the value here unchanged to 0x200000 and set CONFIG_RELOCATABLE=y.
617 Otherwise if you plan to use vmlinux for capturing the crash dump
618 change this value to start of the reserved region (Typically 16MB
619 0x1000000). In other words, it can be set based on the "X" value as
620 specified in the "crashkernel=YM@XM" command line boot parameter
621 passed to the panic-ed kernel. Typically this parameter is set as
622 crashkernel=64M@16M. Please take a look at
623 Documentation/kdump/kdump.txt for more details about crash dumps.
625 Usage of bzImage for capturing the crash dump is advantageous as
626 one does not have to build two kernels. Same kernel can be used
627 as production kernel and capture kernel.
629 Don't change this unless you know what you are doing.
632 bool "Enable seccomp to safely compute untrusted bytecode"
636 This kernel feature is useful for number crunching applications
637 that may need to compute untrusted bytecode during their
638 execution. By using pipes or other transports made available to
639 the process as file descriptors supporting the read/write
640 syscalls, it's possible to isolate those applications in
641 their own address space using seccomp. Once seccomp is
642 enabled via /proc/<pid>/seccomp, it cannot be disabled
643 and the task is only allowed to execute a few safe syscalls
644 defined by each seccomp mode.
646 If unsure, say Y. Only embedded should say N here.
648 config CC_STACKPROTECTOR
649 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
650 depends on EXPERIMENTAL
652 This option turns on the -fstack-protector GCC feature. This
653 feature puts, at the beginning of critical functions, a canary
654 value on the stack just before the return address, and validates
655 the value just before actually returning. Stack based buffer
656 overflows (that need to overwrite this return address) now also
657 overwrite the canary, which gets detected and the attack is then
658 neutralized via a kernel panic.
660 This feature requires gcc version 4.2 or above, or a distribution
661 gcc with the feature backported. Older versions are automatically
662 detected and for those versions, this configuration option is ignored.
664 config CC_STACKPROTECTOR_ALL
665 bool "Use stack-protector for all functions"
666 depends on CC_STACKPROTECTOR
668 Normally, GCC only inserts the canary value protection for
669 functions that use large-ish on-stack buffers. By enabling
670 this option, GCC will be asked to do this for ALL functions.
672 source kernel/Kconfig.hz
676 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
681 # Use the generic interrupt handling code in kernel/irq/:
683 config GENERIC_HARDIRQS
687 config GENERIC_IRQ_PROBE
691 # we have no ISA slots, but we do have ISA-style DMA.
696 config GENERIC_PENDING_IRQ
698 depends on GENERIC_HARDIRQS && SMP
701 menu "Power management options"
703 source kernel/power/Kconfig
705 source "drivers/acpi/Kconfig"
707 source "arch/x86/kernel/cpufreq/Kconfig"
711 menu "Bus options (PCI etc.)"
715 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
717 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
724 bool "Support mmconfig PCI config space access"
725 depends on PCI && ACPI
727 source "drivers/pci/pcie/Kconfig"
729 source "drivers/pci/Kconfig"
731 source "drivers/pcmcia/Kconfig"
733 source "drivers/pci/hotplug/Kconfig"
738 menu "Executable file formats / Emulations"
740 source "fs/Kconfig.binfmt"
742 config IA32_EMULATION
743 bool "IA32 Emulation"
745 Include code to run 32-bit programs under a 64-bit kernel. You should likely
746 turn this on, unless you're 100% sure that you don't have any 32-bit programs
750 tristate "IA32 a.out support"
751 depends on IA32_EMULATION
753 Support old a.out binaries in the 32bit emulation.
757 depends on IA32_EMULATION
760 config COMPAT_FOR_U64_ALIGNMENT
763 config SYSVIPC_COMPAT
765 depends on COMPAT && SYSVIPC
772 source drivers/Kconfig
774 source "drivers/firmware/Kconfig"
778 menu "Instrumentation Support"
779 depends on EXPERIMENTAL
781 source "arch/x86_64/oprofile/Kconfig"
785 depends on KALLSYMS && MODULES
787 Kprobes allows you to trap at almost any kernel address and
788 execute a callback function. register_kprobe() establishes
789 a probepoint and specifies the callback. Kprobes is useful
790 for kernel debugging, non-intrusive instrumentation and testing.
791 If in doubt, say "N".
794 source "arch/x86_64/Kconfig.debug"
796 source "security/Kconfig"
798 source "crypto/Kconfig"