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, Pentium D and older Nocona/Dempsey
179 Xeon CPUs with Intel 64bit which is compatible with x86-64.
180 Note that the latest Xeons (Xeon 51xx and 53xx) are not based on the
181 Netburst core and shouldn't use this option. You can distinguish them
182 using the cpu family field
183 in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one.
186 bool "Intel Core2 / newer Xeon"
188 Optimize for Intel Core2 and newer Xeons (51xx)
189 You can distinguish the newer Xeons from the older ones using
190 the cpu family field in /proc/cpuinfo. 15 is an older Xeon
191 (use CONFIG_MPSC then), 6 is a newer one.
194 bool "Generic-x86-64"
197 Run equally well on all x86-64 CPUs.
202 # Define implied options from the CPU selection here
204 config X86_L1_CACHE_BYTES
206 default "128" if GENERIC_CPU || MPSC
207 default "64" if MK8 || MCORE2
209 config X86_L1_CACHE_SHIFT
211 default "7" if GENERIC_CPU || MPSC
212 default "6" if MK8 || MCORE2
214 config X86_INTERNODE_CACHE_BYTES
216 default "4096" if X86_VSMP
217 default X86_L1_CACHE_BYTES if !X86_VSMP
228 tristate "/dev/cpu/microcode - Intel CPU microcode support"
231 If you say Y here the 'File systems' section, you will be
232 able to update the microcode on Intel processors. You will
233 obviously need the actual microcode binary data itself which is
234 not shipped with the Linux kernel.
236 For latest news and information on obtaining all the required
237 ingredients for this driver, check:
238 <http://www.urbanmyth.org/microcode/>.
240 To compile this driver as a module, choose M here: the
241 module will be called microcode.
242 If you use modprobe or kmod you may also want to add the line
243 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
245 config MICROCODE_OLD_INTERFACE
251 tristate "/dev/cpu/*/msr - Model-specific register support"
253 This device gives privileged processes access to the x86
254 Model-Specific Registers (MSRs). It is a character device with
255 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
256 MSR accesses are directed to a specific CPU on multi-processor
260 tristate "/dev/cpu/*/cpuid - CPU information support"
262 This device gives processes access to the x86 CPUID instruction to
263 be executed on a specific processor. It is a character device
264 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
269 depends on SMP && !MK8
272 config MATH_EMULATION
285 config X86_LOCAL_APIC
290 bool "MTRR (Memory Type Range Register) support"
292 On Intel P6 family processors (Pentium Pro, Pentium II and later)
293 the Memory Type Range Registers (MTRRs) may be used to control
294 processor access to memory ranges. This is most useful if you have
295 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
296 allows bus write transfers to be combined into a larger transfer
297 before bursting over the PCI/AGP bus. This can increase performance
298 of image write operations 2.5 times or more. Saying Y here creates a
299 /proc/mtrr file which may be used to manipulate your processor's
300 MTRRs. Typically the X server should use this.
302 This code has a reasonably generic interface so that similar
303 control registers on other processors can be easily supported
306 Saying Y here also fixes a problem with buggy SMP BIOSes which only
307 set the MTRRs for the boot CPU and not for the secondary CPUs. This
308 can lead to all sorts of problems, so it's good to say Y here.
310 Just say Y here, all x86-64 machines support MTRRs.
312 See <file:Documentation/mtrr.txt> for more information.
315 bool "Symmetric multi-processing support"
317 This enables support for systems with more than one CPU. If you have
318 a system with only one CPU, like most personal computers, say N. If
319 you have a system with more than one CPU, say Y.
321 If you say N here, the kernel will run on single and multiprocessor
322 machines, but will use only one CPU of a multiprocessor machine. If
323 you say Y here, the kernel will run on many, but not all,
324 singleprocessor machines. On a singleprocessor machine, the kernel
325 will run faster if you say N here.
327 If you don't know what to do here, say N.
330 bool "SMT (Hyperthreading) scheduler support"
334 SMT scheduler support improves the CPU scheduler's decision making
335 when dealing with Intel Pentium 4 chips with HyperThreading at a
336 cost of slightly increased overhead in some places. If unsure say
340 bool "Multi-core scheduler support"
344 Multi-core scheduler support improves the CPU scheduler's decision
345 making when dealing with multi-core CPU chips at a cost of slightly
346 increased overhead in some places. If unsure say N here.
348 source "kernel/Kconfig.preempt"
351 bool "Non Uniform Memory Access (NUMA) Support"
354 Enable NUMA (Non Uniform Memory Access) support. The kernel
355 will try to allocate memory used by a CPU on the local memory
356 controller of the CPU and add some more NUMA awareness to the kernel.
357 This code is recommended on all multiprocessor Opteron systems.
358 If the system is EM64T, you should say N unless your system is EM64T
362 bool "Old style AMD Opteron NUMA detection"
363 depends on NUMA && PCI
366 Enable K8 NUMA node topology detection. You should say Y here if
367 you have a multi processor AMD K8 system. This uses an old
368 method to read the NUMA configuration directly from the builtin
369 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
370 instead, which also takes priority if both are compiled in.
375 depends on NEED_MULTIPLE_NODES
377 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
379 config X86_64_ACPI_NUMA
380 bool "ACPI NUMA detection"
387 Enable ACPI SRAT based node topology detection.
390 bool "NUMA emulation"
393 Enable NUMA emulation. A flat machine will be split
394 into virtual nodes when booted with "numa=fake=N", where N is the
395 number of nodes. This is only useful for debugging.
397 config ARCH_DISCONTIGMEM_ENABLE
402 config ARCH_DISCONTIGMEM_DEFAULT
406 config ARCH_SPARSEMEM_ENABLE
408 depends on (NUMA || EXPERIMENTAL)
409 select SPARSEMEM_VMEMMAP_ENABLE
411 config ARCH_MEMORY_PROBE
413 depends on MEMORY_HOTPLUG
415 config ARCH_FLATMEM_ENABLE
421 config MEMORY_HOTPLUG_RESERVE
423 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
425 config HAVE_ARCH_EARLY_PFN_TO_NID
429 config OUT_OF_LINE_PFN_TO_PAGE
431 depends on DISCONTIGMEM
434 int "Maximum number of CPUs (2-255)"
439 This allows you to specify the maximum number of CPUs which this
440 kernel will support. Current maximum is 255 CPUs due to
441 APIC addressing limits. Less depending on the hardware.
443 This is purely to save memory - each supported CPU requires
444 memory in the static kernel configuration.
446 config PHYSICAL_ALIGN
451 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
452 depends on SMP && HOTPLUG && EXPERIMENTAL
454 Say Y here to experiment with turning CPUs off and on. CPUs
455 can be controlled through /sys/devices/system/cpu/cpu#.
456 This is also required for suspend/hibernation on SMP systems.
458 Say N if you want to disable CPU hotplug and don't need to
461 config ARCH_ENABLE_MEMORY_HOTPLUG
468 Use the IA-PC HPET (High Precision Event Timer) to manage
469 time in preference to the PIT and RTC, if a HPET is
470 present. The HPET provides a stable time base on SMP
471 systems, unlike the TSC, but it is more expensive to access,
472 as it is off-chip. You can find the HPET spec at
473 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
475 config HPET_EMULATE_RTC
476 bool "Provide RTC interrupt"
477 depends on HPET_TIMER && RTC=y
479 # Mark as embedded because too many people got it wrong.
480 # The code disables itself when not needed.
482 bool "IOMMU support" if EMBEDDED
488 Support for full DMA access of devices with 32bit memory access only
489 on systems with more than 3GB. This is usually needed for USB,
490 sound, many IDE/SATA chipsets and some other devices.
491 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
492 based hardware IOMMU and a software bounce buffer based IOMMU used
493 on Intel systems and as fallback.
494 The code is only active when needed (enough memory and limited
495 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
499 bool "IBM Calgary IOMMU support"
501 depends on PCI && EXPERIMENTAL
503 Support for hardware IOMMUs in IBM's xSeries x366 and x460
504 systems. Needed to run systems with more than 3GB of memory
505 properly with 32-bit PCI devices that do not support DAC
506 (Double Address Cycle). Calgary also supports bus level
507 isolation, where all DMAs pass through the IOMMU. This
508 prevents them from going anywhere except their intended
509 destination. This catches hard-to-find kernel bugs and
510 mis-behaving drivers and devices that do not use the DMA-API
511 properly to set up their DMA buffers. The IOMMU can be
512 turned off at boot time with the iommu=off parameter.
513 Normally the kernel will make the right choice by itself.
516 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
517 bool "Should Calgary be enabled by default?"
519 depends on CALGARY_IOMMU
521 Should Calgary be enabled by default? if you choose 'y', Calgary
522 will be used (if it exists). If you choose 'n', Calgary will not be
523 used even if it exists. If you choose 'n' and would like to use
524 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
527 # need this always selected by IOMMU for the VIA workaround
531 Support for software bounce buffers used on x86-64 systems
532 which don't have a hardware IOMMU (e.g. the current generation
533 of Intel's x86-64 CPUs). Using this PCI devices which can only
534 access 32-bits of memory can be used on systems with more than
535 3 GB of memory. If unsure, say Y.
538 bool "Machine check support" if EMBEDDED
541 Include a machine check error handler to report hardware errors.
542 This version will require the mcelog utility to decode some
543 machine check error logs. See
544 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
547 bool "Intel MCE features"
548 depends on X86_MCE && X86_LOCAL_APIC
551 Additional support for intel specific MCE features such as
555 bool "AMD MCE features"
556 depends on X86_MCE && X86_LOCAL_APIC
559 Additional support for AMD specific MCE features such as
560 the DRAM Error Threshold.
563 bool "kexec system call"
565 kexec is a system call that implements the ability to shutdown your
566 current kernel, and to start another kernel. It is like a reboot
567 but it is independent of the system firmware. And like a reboot
568 you can start any kernel with it, not just Linux.
570 The name comes from the similarity to the exec system call.
572 It is an ongoing process to be certain the hardware in a machine
573 is properly shutdown, so do not be surprised if this code does not
574 initially work for you. It may help to enable device hotplugging
575 support. As of this writing the exact hardware interface is
576 strongly in flux, so no good recommendation can be made.
579 bool "kernel crash dumps (EXPERIMENTAL)"
580 depends on EXPERIMENTAL
582 Generate crash dump after being started by kexec.
583 This should be normally only set in special crash dump kernels
584 which are loaded in the main kernel with kexec-tools into
585 a specially reserved region and then later executed after
586 a crash by kdump/kexec. The crash dump kernel must be compiled
587 to a memory address not used by the main kernel or BIOS using
588 PHYSICAL_START, or it must be built as a relocatable image
589 (CONFIG_RELOCATABLE=y).
590 For more details see Documentation/kdump/kdump.txt
593 bool "Build a relocatable kernel (EXPERIMENTAL)"
594 depends on EXPERIMENTAL
596 Builds a relocatable kernel. This enables loading and running
597 a kernel binary from a different physical address than it has
600 One use is for the kexec on panic case where the recovery kernel
601 must live at a different physical address than the primary
604 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
605 it has been loaded at and the compile time physical address
606 (CONFIG_PHYSICAL_START) is ignored.
608 config PHYSICAL_START
609 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
612 This gives the physical address where the kernel is loaded. It
613 should be aligned to 2MB boundary.
615 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
616 bzImage will decompress itself to above physical address and
617 run from there. Otherwise, bzImage will run from the address where
618 it has been loaded by the boot loader and will ignore above physical
621 In normal kdump cases one does not have to set/change this option
622 as now bzImage can be compiled as a completely relocatable image
623 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
624 address. This option is mainly useful for the folks who don't want
625 to use a bzImage for capturing the crash dump and want to use a
628 So if you are using bzImage for capturing the crash dump, leave
629 the value here unchanged to 0x200000 and set CONFIG_RELOCATABLE=y.
630 Otherwise if you plan to use vmlinux for capturing the crash dump
631 change this value to start of the reserved region (Typically 16MB
632 0x1000000). In other words, it can be set based on the "X" value as
633 specified in the "crashkernel=YM@XM" command line boot parameter
634 passed to the panic-ed kernel. Typically this parameter is set as
635 crashkernel=64M@16M. Please take a look at
636 Documentation/kdump/kdump.txt for more details about crash dumps.
638 Usage of bzImage for capturing the crash dump is advantageous as
639 one does not have to build two kernels. Same kernel can be used
640 as production kernel and capture kernel.
642 Don't change this unless you know what you are doing.
645 bool "Enable seccomp to safely compute untrusted bytecode"
649 This kernel feature is useful for number crunching applications
650 that may need to compute untrusted bytecode during their
651 execution. By using pipes or other transports made available to
652 the process as file descriptors supporting the read/write
653 syscalls, it's possible to isolate those applications in
654 their own address space using seccomp. Once seccomp is
655 enabled via /proc/<pid>/seccomp, it cannot be disabled
656 and the task is only allowed to execute a few safe syscalls
657 defined by each seccomp mode.
659 If unsure, say Y. Only embedded should say N here.
661 config CC_STACKPROTECTOR
662 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
663 depends on EXPERIMENTAL
665 This option turns on the -fstack-protector GCC feature. This
666 feature puts, at the beginning of critical functions, a canary
667 value on the stack just before the return address, and validates
668 the value just before actually returning. Stack based buffer
669 overflows (that need to overwrite this return address) now also
670 overwrite the canary, which gets detected and the attack is then
671 neutralized via a kernel panic.
673 This feature requires gcc version 4.2 or above, or a distribution
674 gcc with the feature backported. Older versions are automatically
675 detected and for those versions, this configuration option is ignored.
677 config CC_STACKPROTECTOR_ALL
678 bool "Use stack-protector for all functions"
679 depends on CC_STACKPROTECTOR
681 Normally, GCC only inserts the canary value protection for
682 functions that use large-ish on-stack buffers. By enabling
683 this option, GCC will be asked to do this for ALL functions.
685 source kernel/Kconfig.hz
689 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
694 # Use the generic interrupt handling code in kernel/irq/:
696 config GENERIC_HARDIRQS
700 config GENERIC_IRQ_PROBE
704 # we have no ISA slots, but we do have ISA-style DMA.
709 config GENERIC_PENDING_IRQ
711 depends on GENERIC_HARDIRQS && SMP
714 menu "Power management options"
716 source kernel/power/Kconfig
718 source "drivers/acpi/Kconfig"
720 source "arch/x86/kernel/cpufreq/Kconfig"
724 menu "Bus options (PCI etc.)"
728 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
730 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
737 bool "Support mmconfig PCI config space access"
738 depends on PCI && ACPI
745 source "drivers/pci/pcie/Kconfig"
747 source "drivers/pci/Kconfig"
749 source "drivers/pcmcia/Kconfig"
751 source "drivers/pci/hotplug/Kconfig"
756 menu "Executable file formats / Emulations"
758 source "fs/Kconfig.binfmt"
760 config IA32_EMULATION
761 bool "IA32 Emulation"
763 Include code to run 32-bit programs under a 64-bit kernel. You should likely
764 turn this on, unless you're 100% sure that you don't have any 32-bit programs
768 tristate "IA32 a.out support"
769 depends on IA32_EMULATION
771 Support old a.out binaries in the 32bit emulation.
775 depends on IA32_EMULATION
778 config COMPAT_FOR_U64_ALIGNMENT
781 config SYSVIPC_COMPAT
783 depends on COMPAT && SYSVIPC
790 source drivers/Kconfig
792 source "drivers/firmware/Kconfig"
796 menu "Instrumentation Support"
798 source "arch/x86/oprofile/Kconfig"
802 depends on KALLSYMS && MODULES
804 Kprobes allows you to trap at almost any kernel address and
805 execute a callback function. register_kprobe() establishes
806 a probepoint and specifies the callback. Kprobes is useful
807 for kernel debugging, non-intrusive instrumentation and testing.
808 If in doubt, say "N".
811 source "arch/x86_64/Kconfig.debug"
813 source "security/Kconfig"
815 source "crypto/Kconfig"