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
39 config LOCKDEP_SUPPORT
43 config STACKTRACE_SUPPORT
47 config SEMAPHORE_SLEEPERS
65 config RWSEM_GENERIC_SPINLOCK
69 config RWSEM_XCHGADD_ALGORITHM
72 config GENERIC_HWEIGHT
76 config GENERIC_CALIBRATE_DELAY
88 config GENERIC_ISA_DMA
96 config ARCH_MAY_HAVE_PC_FDC
100 config ARCH_POPULATES_NODE_MAP
116 config ARCH_HAS_ILOG2_U32
120 config ARCH_HAS_ILOG2_U64
124 source "init/Kconfig"
127 menu "Processor type and features"
130 prompt "Subarchitecture Type"
136 Choose this option if your computer is a standard PC or compatible.
139 bool "Support for ScaleMP vSMP"
142 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
143 supposed to run on these EM64T-based machines. Only choose this option
144 if you have one of these machines.
149 prompt "Processor family"
153 bool "AMD-Opteron/Athlon64"
155 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
158 bool "Intel P4 / older Netburst based Xeon"
160 Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
161 with Intel Extended Memory 64 Technology(EM64T). For details see
162 <http://www.intel.com/technology/64bitextensions/>.
163 Note that the latest Xeons (Xeon 51xx and 53xx) are not based on the
164 Netburst core and shouldn't use this option. You can distinguish them
165 using the cpu family field
166 in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one
167 (this rule only applies to systems that support EM64T)
170 bool "Intel Core2 / newer Xeon"
172 Optimize for Intel Core2 and newer Xeons (51xx)
173 You can distinguish the newer Xeons from the older ones using
174 the cpu family field in /proc/cpuinfo. 15 is an older Xeon
175 (use CONFIG_MPSC then), 6 is a newer one. This rule only
176 applies to CPUs that support EM64T.
179 bool "Generic-x86-64"
182 Run equally well on all x86-64 CPUs.
187 # Define implied options from the CPU selection here
189 config X86_L1_CACHE_BYTES
191 default "128" if GENERIC_CPU || MPSC
192 default "64" if MK8 || MCORE2
194 config X86_L1_CACHE_SHIFT
196 default "7" if GENERIC_CPU || MPSC
197 default "6" if MK8 || MCORE2
199 config X86_INTERNODE_CACHE_BYTES
201 default "4096" if X86_VSMP
202 default X86_L1_CACHE_BYTES if !X86_VSMP
213 tristate "/dev/cpu/microcode - Intel CPU microcode support"
216 If you say Y here the 'File systems' section, you will be
217 able to update the microcode on Intel processors. You will
218 obviously need the actual microcode binary data itself which is
219 not shipped with the Linux kernel.
221 For latest news and information on obtaining all the required
222 ingredients for this driver, check:
223 <http://www.urbanmyth.org/microcode/>.
225 To compile this driver as a module, choose M here: the
226 module will be called microcode.
227 If you use modprobe or kmod you may also want to add the line
228 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
230 config MICROCODE_OLD_INTERFACE
236 tristate "/dev/cpu/*/msr - Model-specific register support"
238 This device gives privileged processes access to the x86
239 Model-Specific Registers (MSRs). It is a character device with
240 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
241 MSR accesses are directed to a specific CPU on multi-processor
245 tristate "/dev/cpu/*/cpuid - CPU information support"
247 This device gives processes access to the x86 CPUID instruction to
248 be executed on a specific processor. It is a character device
249 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
254 depends on SMP && !MK8
257 config MATH_EMULATION
270 config X86_LOCAL_APIC
275 bool "MTRR (Memory Type Range Register) support"
277 On Intel P6 family processors (Pentium Pro, Pentium II and later)
278 the Memory Type Range Registers (MTRRs) may be used to control
279 processor access to memory ranges. This is most useful if you have
280 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
281 allows bus write transfers to be combined into a larger transfer
282 before bursting over the PCI/AGP bus. This can increase performance
283 of image write operations 2.5 times or more. Saying Y here creates a
284 /proc/mtrr file which may be used to manipulate your processor's
285 MTRRs. Typically the X server should use this.
287 This code has a reasonably generic interface so that similar
288 control registers on other processors can be easily supported
291 Saying Y here also fixes a problem with buggy SMP BIOSes which only
292 set the MTRRs for the boot CPU and not for the secondary CPUs. This
293 can lead to all sorts of problems, so it's good to say Y here.
295 Just say Y here, all x86-64 machines support MTRRs.
297 See <file:Documentation/mtrr.txt> for more information.
300 bool "Symmetric multi-processing support"
302 This enables support for systems with more than one CPU. If you have
303 a system with only one CPU, like most personal computers, say N. If
304 you have a system with more than one CPU, say Y.
306 If you say N here, the kernel will run on single and multiprocessor
307 machines, but will use only one CPU of a multiprocessor machine. If
308 you say Y here, the kernel will run on many, but not all,
309 singleprocessor machines. On a singleprocessor machine, the kernel
310 will run faster if you say N here.
312 If you don't know what to do here, say N.
315 bool "SMT (Hyperthreading) scheduler support"
319 SMT scheduler support improves the CPU scheduler's decision making
320 when dealing with Intel Pentium 4 chips with HyperThreading at a
321 cost of slightly increased overhead in some places. If unsure say
325 bool "Multi-core scheduler support"
329 Multi-core scheduler support improves the CPU scheduler's decision
330 making when dealing with multi-core CPU chips at a cost of slightly
331 increased overhead in some places. If unsure say N here.
333 source "kernel/Kconfig.preempt"
336 bool "Non Uniform Memory Access (NUMA) Support"
339 Enable NUMA (Non Uniform Memory Access) support. The kernel
340 will try to allocate memory used by a CPU on the local memory
341 controller of the CPU and add some more NUMA awareness to the kernel.
342 This code is recommended on all multiprocessor Opteron systems.
343 If the system is EM64T, you should say N unless your system is EM64T
347 bool "Old style AMD Opteron NUMA detection"
348 depends on NUMA && PCI
351 Enable K8 NUMA node topology detection. You should say Y here if
352 you have a multi processor AMD K8 system. This uses an old
353 method to read the NUMA configuration directly from the builtin
354 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
355 instead, which also takes priority if both are compiled in.
360 depends on NEED_MULTIPLE_NODES
362 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
364 config X86_64_ACPI_NUMA
365 bool "ACPI NUMA detection"
372 Enable ACPI SRAT based node topology detection.
375 bool "NUMA emulation"
378 Enable NUMA emulation. A flat machine will be split
379 into virtual nodes when booted with "numa=fake=N", where N is the
380 number of nodes. This is only useful for debugging.
382 config ARCH_DISCONTIGMEM_ENABLE
387 config ARCH_DISCONTIGMEM_DEFAULT
391 config ARCH_SPARSEMEM_ENABLE
393 depends on (NUMA || EXPERIMENTAL)
395 config ARCH_MEMORY_PROBE
397 depends on MEMORY_HOTPLUG
399 config ARCH_FLATMEM_ENABLE
405 config MEMORY_HOTPLUG_RESERVE
407 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
409 config HAVE_ARCH_EARLY_PFN_TO_NID
413 config OUT_OF_LINE_PFN_TO_PAGE
415 depends on DISCONTIGMEM
418 int "Maximum number of CPUs (2-255)"
423 This allows you to specify the maximum number of CPUs which this
424 kernel will support. Current maximum is 255 CPUs due to
425 APIC addressing limits. Less depending on the hardware.
427 This is purely to save memory - each supported CPU requires
428 memory in the static kernel configuration.
431 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
432 depends on SMP && HOTPLUG && EXPERIMENTAL
434 Say Y here to experiment with turning CPUs off and on. CPUs
435 can be controlled through /sys/devices/system/cpu/cpu#.
436 Say N if you want to disable CPU hotplug.
438 config ARCH_ENABLE_MEMORY_HOTPLUG
445 Use the IA-PC HPET (High Precision Event Timer) to manage
446 time in preference to the PIT and RTC, if a HPET is
447 present. The HPET provides a stable time base on SMP
448 systems, unlike the TSC, but it is more expensive to access,
449 as it is off-chip. You can find the HPET spec at
450 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
452 config HPET_EMULATE_RTC
453 bool "Provide RTC interrupt"
454 depends on HPET_TIMER && RTC=y
456 # Mark as embedded because too many people got it wrong.
457 # The code disables itself when not needed.
459 bool "IOMMU support" if EMBEDDED
465 Support for full DMA access of devices with 32bit memory access only
466 on systems with more than 3GB. This is usually needed for USB,
467 sound, many IDE/SATA chipsets and some other devices.
468 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
469 based hardware IOMMU and a software bounce buffer based IOMMU used
470 on Intel systems and as fallback.
471 The code is only active when needed (enough memory and limited
472 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
476 bool "IBM Calgary IOMMU support"
478 depends on PCI && EXPERIMENTAL
480 Support for hardware IOMMUs in IBM's xSeries x366 and x460
481 systems. Needed to run systems with more than 3GB of memory
482 properly with 32-bit PCI devices that do not support DAC
483 (Double Address Cycle). Calgary also supports bus level
484 isolation, where all DMAs pass through the IOMMU. This
485 prevents them from going anywhere except their intended
486 destination. This catches hard-to-find kernel bugs and
487 mis-behaving drivers and devices that do not use the DMA-API
488 properly to set up their DMA buffers. The IOMMU can be
489 turned off at boot time with the iommu=off parameter.
490 Normally the kernel will make the right choice by itself.
493 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
494 bool "Should Calgary be enabled by default?"
496 depends on CALGARY_IOMMU
498 Should Calgary be enabled by default? if you choose 'y', Calgary
499 will be used (if it exists). If you choose 'n', Calgary will not be
500 used even if it exists. If you choose 'n' and would like to use
501 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
504 # need this always selected by IOMMU for the VIA workaround
508 Support for software bounce buffers used on x86-64 systems
509 which don't have a hardware IOMMU (e.g. the current generation
510 of Intel's x86-64 CPUs). Using this PCI devices which can only
511 access 32-bits of memory can be used on systems with more than
512 3 GB of memory. If unsure, say Y.
515 bool "Machine check support" if EMBEDDED
518 Include a machine check error handler to report hardware errors.
519 This version will require the mcelog utility to decode some
520 machine check error logs. See
521 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
524 bool "Intel MCE features"
525 depends on X86_MCE && X86_LOCAL_APIC
528 Additional support for intel specific MCE features such as
532 bool "AMD MCE features"
533 depends on X86_MCE && X86_LOCAL_APIC
536 Additional support for AMD specific MCE features such as
537 the DRAM Error Threshold.
540 bool "kexec system call"
542 kexec is a system call that implements the ability to shutdown your
543 current kernel, and to start another kernel. It is like a reboot
544 but it is independent of the system firmware. And like a reboot
545 you can start any kernel with it, not just Linux.
547 The name comes from the similarity to the exec system call.
549 It is an ongoing process to be certain the hardware in a machine
550 is properly shutdown, so do not be surprised if this code does not
551 initially work for you. It may help to enable device hotplugging
552 support. As of this writing the exact hardware interface is
553 strongly in flux, so no good recommendation can be made.
556 bool "kernel crash dumps (EXPERIMENTAL)"
557 depends on EXPERIMENTAL
559 Generate crash dump after being started by kexec.
560 This should be normally only set in special crash dump kernels
561 which are loaded in the main kernel with kexec-tools into
562 a specially reserved region and then later executed after
563 a crash by kdump/kexec. The crash dump kernel must be compiled
564 to a memory address not used by the main kernel or BIOS using
566 For more details see Documentation/kdump/kdump.txt
569 bool "Build a relocatable kernel(EXPERIMENTAL)"
570 depends on EXPERIMENTAL
572 Builds a relocatable kernel. This enables loading and running
573 a kernel binary from a different physical address than it has
576 One use is for the kexec on panic case where the recovery kernel
577 must live at a different physical address than the primary
580 Note: If CONFIG_RELOCATABLE=y, then kernel run from the address
581 it has been loaded at and compile time physical address
582 (CONFIG_PHYSICAL_START) is ignored.
584 config PHYSICAL_START
585 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
588 This gives the physical address where the kernel is loaded. It
589 should be aligned to 2MB boundary.
591 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
592 bzImage will decompress itself to above physical address and
593 run from there. Otherwise, bzImage will run from the address where
594 it has been loaded by the boot loader and will ignore above physical
597 In normal kdump cases one does not have to set/change this option
598 as now bzImage can be compiled as a completely relocatable image
599 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
600 address. This option is mainly useful for the folks who don't want
601 to use a bzImage for capturing the crash dump and want to use a
604 So if you are using bzImage for capturing the crash dump, leave
605 the value here unchanged to 0x200000 and set CONFIG_RELOCATABLE=y.
606 Otherwise if you plan to use vmlinux for capturing the crash dump
607 change this value to start of the reserved region (Typically 16MB
608 0x1000000). In other words, it can be set based on the "X" value as
609 specified in the "crashkernel=YM@XM" command line boot parameter
610 passed to the panic-ed kernel. Typically this parameter is set as
611 crashkernel=64M@16M. Please take a look at
612 Documentation/kdump/kdump.txt for more details about crash dumps.
614 Usage of bzImage for capturing the crash dump is advantageous as
615 one does not have to build two kernels. Same kernel can be used
616 as production kernel and capture kernel.
618 Don't change this unless you know what you are doing.
621 bool "Enable seccomp to safely compute untrusted bytecode"
625 This kernel feature is useful for number crunching applications
626 that may need to compute untrusted bytecode during their
627 execution. By using pipes or other transports made available to
628 the process as file descriptors supporting the read/write
629 syscalls, it's possible to isolate those applications in
630 their own address space using seccomp. Once seccomp is
631 enabled via /proc/<pid>/seccomp, it cannot be disabled
632 and the task is only allowed to execute a few safe syscalls
633 defined by each seccomp mode.
635 If unsure, say Y. Only embedded should say N here.
637 config CC_STACKPROTECTOR
638 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
639 depends on EXPERIMENTAL
641 This option turns on the -fstack-protector GCC feature. This
642 feature puts, at the beginning of critical functions, a canary
643 value on the stack just before the return address, and validates
644 the value just before actually returning. Stack based buffer
645 overflows (that need to overwrite this return address) now also
646 overwrite the canary, which gets detected and the attack is then
647 neutralized via a kernel panic.
649 This feature requires gcc version 4.2 or above, or a distribution
650 gcc with the feature backported. Older versions are automatically
651 detected and for those versions, this configuration option is ignored.
653 config CC_STACKPROTECTOR_ALL
654 bool "Use stack-protector for all functions"
655 depends on CC_STACKPROTECTOR
657 Normally, GCC only inserts the canary value protection for
658 functions that use large-ish on-stack buffers. By enabling
659 this option, GCC will be asked to do this for ALL functions.
661 source kernel/Kconfig.hz
664 bool "Function reordering"
667 This option enables the toolchain to reorder functions for a more
668 optimal TLB usage. If you have pretty much any version of binutils,
669 this can increase your kernel build time by roughly one minute.
673 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
678 # Use the generic interrupt handling code in kernel/irq/:
680 config GENERIC_HARDIRQS
684 config GENERIC_IRQ_PROBE
688 # we have no ISA slots, but we do have ISA-style DMA.
693 config GENERIC_PENDING_IRQ
695 depends on GENERIC_HARDIRQS && SMP
698 menu "Power management options"
700 source kernel/power/Kconfig
702 source "drivers/acpi/Kconfig"
704 source "arch/x86_64/kernel/cpufreq/Kconfig"
708 menu "Bus options (PCI etc.)"
713 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
720 bool "Support mmconfig PCI config space access"
721 depends on PCI && ACPI
723 source "drivers/pci/pcie/Kconfig"
725 source "drivers/pci/Kconfig"
727 source "drivers/pcmcia/Kconfig"
729 source "drivers/pci/hotplug/Kconfig"
734 menu "Executable file formats / Emulations"
736 source "fs/Kconfig.binfmt"
738 config IA32_EMULATION
739 bool "IA32 Emulation"
741 Include code to run 32-bit programs under a 64-bit kernel. You should likely
742 turn this on, unless you're 100% sure that you don't have any 32-bit programs
746 tristate "IA32 a.out support"
747 depends on IA32_EMULATION
749 Support old a.out binaries in the 32bit emulation.
753 depends on IA32_EMULATION
756 config SYSVIPC_COMPAT
758 depends on COMPAT && SYSVIPC
765 source drivers/Kconfig
767 source "drivers/firmware/Kconfig"
771 menu "Instrumentation Support"
772 depends on EXPERIMENTAL
774 source "arch/x86_64/oprofile/Kconfig"
777 bool "Kprobes (EXPERIMENTAL)"
778 depends on KALLSYMS && EXPERIMENTAL && MODULES
780 Kprobes allows you to trap at almost any kernel address and
781 execute a callback function. register_kprobe() establishes
782 a probepoint and specifies the callback. Kprobes is useful
783 for kernel debugging, non-intrusive instrumentation and testing.
784 If in doubt, say "N".
787 source "arch/x86_64/Kconfig.debug"
789 source "security/Kconfig"
791 source "crypto/Kconfig"