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/>.
35 config LOCKDEP_SUPPORT
39 config STACKTRACE_SUPPORT
43 config SEMAPHORE_SLEEPERS
61 config RWSEM_GENERIC_SPINLOCK
65 config RWSEM_XCHGADD_ALGORITHM
68 config GENERIC_HWEIGHT
72 config GENERIC_CALIBRATE_DELAY
84 config GENERIC_ISA_DMA
92 config ARCH_MAY_HAVE_PC_FDC
96 config ARCH_POPULATES_NODE_MAP
112 config ARCH_HAS_ILOG2_U32
116 config ARCH_HAS_ILOG2_U64
120 source "init/Kconfig"
123 menu "Processor type and features"
126 prompt "Subarchitecture Type"
132 Choose this option if your computer is a standard PC or compatible.
135 bool "Support for ScaleMP vSMP"
138 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
139 supposed to run on these EM64T-based machines. Only choose this option
140 if you have one of these machines.
145 prompt "Processor family"
149 bool "AMD-Opteron/Athlon64"
151 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
154 bool "Intel P4 / older Netburst based Xeon"
156 Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
157 with Intel Extended Memory 64 Technology(EM64T). For details see
158 <http://www.intel.com/technology/64bitextensions/>.
159 Note that the latest Xeons (Xeon 51xx and 53xx) are not based on the
160 Netburst core and shouldn't use this option. You can distinguish them
161 using the cpu family field
162 in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one
163 (this rule only applies to systems that support EM64T)
166 bool "Intel Core2 / newer Xeon"
168 Optimize for Intel Core2 and newer Xeons (51xx)
169 You can distinguish the newer Xeons from the older ones using
170 the cpu family field in /proc/cpuinfo. 15 is an older Xeon
171 (use CONFIG_MPSC then), 6 is a newer one. This rule only
172 applies to CPUs that support EM64T.
175 bool "Generic-x86-64"
178 Run equally well on all x86-64 CPUs.
183 # Define implied options from the CPU selection here
185 config X86_L1_CACHE_BYTES
187 default "128" if GENERIC_CPU || MPSC
188 default "64" if MK8 || MCORE2
190 config X86_L1_CACHE_SHIFT
192 default "7" if GENERIC_CPU || MPSC
193 default "6" if MK8 || MCORE2
195 config X86_INTERNODE_CACHE_BYTES
197 default "4096" if X86_VSMP
198 default X86_L1_CACHE_BYTES if !X86_VSMP
209 tristate "/dev/cpu/microcode - Intel CPU microcode support"
212 If you say Y here the 'File systems' section, you will be
213 able to update the microcode on Intel processors. You will
214 obviously need the actual microcode binary data itself which is
215 not shipped with the Linux kernel.
217 For latest news and information on obtaining all the required
218 ingredients for this driver, check:
219 <http://www.urbanmyth.org/microcode/>.
221 To compile this driver as a module, choose M here: the
222 module will be called microcode.
223 If you use modprobe or kmod you may also want to add the line
224 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
226 config MICROCODE_OLD_INTERFACE
232 tristate "/dev/cpu/*/msr - Model-specific register support"
234 This device gives privileged processes access to the x86
235 Model-Specific Registers (MSRs). It is a character device with
236 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
237 MSR accesses are directed to a specific CPU on multi-processor
241 tristate "/dev/cpu/*/cpuid - CPU information support"
243 This device gives processes access to the x86 CPUID instruction to
244 be executed on a specific processor. It is a character device
245 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
250 depends on SMP && !MK8
253 config MATH_EMULATION
266 config X86_LOCAL_APIC
271 bool "MTRR (Memory Type Range Register) support"
273 On Intel P6 family processors (Pentium Pro, Pentium II and later)
274 the Memory Type Range Registers (MTRRs) may be used to control
275 processor access to memory ranges. This is most useful if you have
276 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
277 allows bus write transfers to be combined into a larger transfer
278 before bursting over the PCI/AGP bus. This can increase performance
279 of image write operations 2.5 times or more. Saying Y here creates a
280 /proc/mtrr file which may be used to manipulate your processor's
281 MTRRs. Typically the X server should use this.
283 This code has a reasonably generic interface so that similar
284 control registers on other processors can be easily supported
287 Saying Y here also fixes a problem with buggy SMP BIOSes which only
288 set the MTRRs for the boot CPU and not for the secondary CPUs. This
289 can lead to all sorts of problems, so it's good to say Y here.
291 Just say Y here, all x86-64 machines support MTRRs.
293 See <file:Documentation/mtrr.txt> for more information.
296 bool "Symmetric multi-processing support"
298 This enables support for systems with more than one CPU. If you have
299 a system with only one CPU, like most personal computers, say N. If
300 you have a system with more than one CPU, say Y.
302 If you say N here, the kernel will run on single and multiprocessor
303 machines, but will use only one CPU of a multiprocessor machine. If
304 you say Y here, the kernel will run on many, but not all,
305 singleprocessor machines. On a singleprocessor machine, the kernel
306 will run faster if you say N here.
308 If you don't know what to do here, say N.
311 bool "SMT (Hyperthreading) scheduler support"
315 SMT scheduler support improves the CPU scheduler's decision making
316 when dealing with Intel Pentium 4 chips with HyperThreading at a
317 cost of slightly increased overhead in some places. If unsure say
321 bool "Multi-core scheduler support"
325 Multi-core scheduler support improves the CPU scheduler's decision
326 making when dealing with multi-core CPU chips at a cost of slightly
327 increased overhead in some places. If unsure say N here.
329 source "kernel/Kconfig.preempt"
332 bool "Non Uniform Memory Access (NUMA) Support"
335 Enable NUMA (Non Uniform Memory Access) support. The kernel
336 will try to allocate memory used by a CPU on the local memory
337 controller of the CPU and add some more NUMA awareness to the kernel.
338 This code is recommended on all multiprocessor Opteron systems.
339 If the system is EM64T, you should say N unless your system is EM64T
343 bool "Old style AMD Opteron NUMA detection"
344 depends on NUMA && PCI
347 Enable K8 NUMA node topology detection. You should say Y here if
348 you have a multi processor AMD K8 system. This uses an old
349 method to read the NUMA configuration directly from the builtin
350 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
351 instead, which also takes priority if both are compiled in.
356 depends on NEED_MULTIPLE_NODES
358 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
360 config X86_64_ACPI_NUMA
361 bool "ACPI NUMA detection"
368 Enable ACPI SRAT based node topology detection.
371 bool "NUMA emulation"
374 Enable NUMA emulation. A flat machine will be split
375 into virtual nodes when booted with "numa=fake=N", where N is the
376 number of nodes. This is only useful for debugging.
378 config ARCH_DISCONTIGMEM_ENABLE
383 config ARCH_DISCONTIGMEM_DEFAULT
387 config ARCH_SPARSEMEM_ENABLE
389 depends on (NUMA || EXPERIMENTAL)
391 config ARCH_MEMORY_PROBE
393 depends on MEMORY_HOTPLUG
395 config ARCH_FLATMEM_ENABLE
401 config MEMORY_HOTPLUG_RESERVE
403 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
405 config HAVE_ARCH_EARLY_PFN_TO_NID
409 config OUT_OF_LINE_PFN_TO_PAGE
411 depends on DISCONTIGMEM
414 int "Maximum number of CPUs (2-256)"
419 This allows you to specify the maximum number of CPUs which this
420 kernel will support. Current maximum is 256 CPUs due to
421 APIC addressing limits. Less depending on the hardware.
423 This is purely to save memory - each supported CPU requires
424 memory in the static kernel configuration.
427 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
428 depends on SMP && HOTPLUG && EXPERIMENTAL
430 Say Y here to experiment with turning CPUs off and on. CPUs
431 can be controlled through /sys/devices/system/cpu/cpu#.
432 Say N if you want to disable CPU hotplug.
434 config ARCH_ENABLE_MEMORY_HOTPLUG
441 Use the IA-PC HPET (High Precision Event Timer) to manage
442 time in preference to the PIT and RTC, if a HPET is
443 present. The HPET provides a stable time base on SMP
444 systems, unlike the TSC, but it is more expensive to access,
445 as it is off-chip. You can find the HPET spec at
446 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
448 config HPET_EMULATE_RTC
449 bool "Provide RTC interrupt"
450 depends on HPET_TIMER && RTC=y
452 # Mark as embedded because too many people got it wrong.
453 # The code disables itself when not needed.
455 bool "IOMMU support" if EMBEDDED
461 Support for full DMA access of devices with 32bit memory access only
462 on systems with more than 3GB. This is usually needed for USB,
463 sound, many IDE/SATA chipsets and some other devices.
464 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
465 based hardware IOMMU and a software bounce buffer based IOMMU used
466 on Intel systems and as fallback.
467 The code is only active when needed (enough memory and limited
468 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
472 bool "IBM Calgary IOMMU support"
474 depends on PCI && EXPERIMENTAL
476 Support for hardware IOMMUs in IBM's xSeries x366 and x460
477 systems. Needed to run systems with more than 3GB of memory
478 properly with 32-bit PCI devices that do not support DAC
479 (Double Address Cycle). Calgary also supports bus level
480 isolation, where all DMAs pass through the IOMMU. This
481 prevents them from going anywhere except their intended
482 destination. This catches hard-to-find kernel bugs and
483 mis-behaving drivers and devices that do not use the DMA-API
484 properly to set up their DMA buffers. The IOMMU can be
485 turned off at boot time with the iommu=off parameter.
486 Normally the kernel will make the right choice by itself.
489 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
490 bool "Should Calgary be enabled by default?"
492 depends on CALGARY_IOMMU
494 Should Calgary be enabled by default? if you choose 'y', Calgary
495 will be used (if it exists). If you choose 'n', Calgary will not be
496 used even if it exists. If you choose 'n' and would like to use
497 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
500 # need this always selected by IOMMU for the VIA workaround
504 Support for software bounce buffers used on x86-64 systems
505 which don't have a hardware IOMMU (e.g. the current generation
506 of Intel's x86-64 CPUs). Using this PCI devices which can only
507 access 32-bits of memory can be used on systems with more than
508 3 GB of memory. If unsure, say Y.
511 bool "Machine check support" if EMBEDDED
514 Include a machine check error handler to report hardware errors.
515 This version will require the mcelog utility to decode some
516 machine check error logs. See
517 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
520 bool "Intel MCE features"
521 depends on X86_MCE && X86_LOCAL_APIC
524 Additional support for intel specific MCE features such as
528 bool "AMD MCE features"
529 depends on X86_MCE && X86_LOCAL_APIC
532 Additional support for AMD specific MCE features such as
533 the DRAM Error Threshold.
536 bool "kexec system call"
538 kexec is a system call that implements the ability to shutdown your
539 current kernel, and to start another kernel. It is like a reboot
540 but it is independent of the system firmware. And like a reboot
541 you can start any kernel with it, not just Linux.
543 The name comes from the similarity to the exec system call.
545 It is an ongoing process to be certain the hardware in a machine
546 is properly shutdown, so do not be surprised if this code does not
547 initially work for you. It may help to enable device hotplugging
548 support. As of this writing the exact hardware interface is
549 strongly in flux, so no good recommendation can be made.
552 bool "kernel crash dumps (EXPERIMENTAL)"
553 depends on EXPERIMENTAL
555 Generate crash dump after being started by kexec.
556 This should be normally only set in special crash dump kernels
557 which are loaded in the main kernel with kexec-tools into
558 a specially reserved region and then later executed after
559 a crash by kdump/kexec. The crash dump kernel must be compiled
560 to a memory address not used by the main kernel or BIOS using
562 For more details see Documentation/kdump/kdump.txt
564 config PHYSICAL_START
565 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
566 default "0x1000000" if CRASH_DUMP
569 This gives the physical address where the kernel is loaded. Normally
570 for regular kernels this value is 0x200000 (2MB). But in the case
571 of kexec on panic the fail safe kernel needs to run at a different
572 address than the panic-ed kernel. This option is used to set the load
573 address for kernels used to capture crash dump on being kexec'ed
574 after panic. The default value for crash dump kernels is
575 0x1000000 (16MB). This can also be set based on the "X" value as
576 specified in the "crashkernel=YM@XM" command line boot parameter
577 passed to the panic-ed kernel. Typically this parameter is set as
578 crashkernel=64M@16M. Please take a look at
579 Documentation/kdump/kdump.txt for more details about crash dumps.
581 Don't change this unless you know what you are doing.
584 bool "Enable seccomp to safely compute untrusted bytecode"
588 This kernel feature is useful for number crunching applications
589 that may need to compute untrusted bytecode during their
590 execution. By using pipes or other transports made available to
591 the process as file descriptors supporting the read/write
592 syscalls, it's possible to isolate those applications in
593 their own address space using seccomp. Once seccomp is
594 enabled via /proc/<pid>/seccomp, it cannot be disabled
595 and the task is only allowed to execute a few safe syscalls
596 defined by each seccomp mode.
598 If unsure, say Y. Only embedded should say N here.
600 config CC_STACKPROTECTOR
601 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
602 depends on EXPERIMENTAL
604 This option turns on the -fstack-protector GCC feature. This
605 feature puts, at the beginning of critical functions, a canary
606 value on the stack just before the return address, and validates
607 the value just before actually returning. Stack based buffer
608 overflows (that need to overwrite this return address) now also
609 overwrite the canary, which gets detected and the attack is then
610 neutralized via a kernel panic.
612 This feature requires gcc version 4.2 or above, or a distribution
613 gcc with the feature backported. Older versions are automatically
614 detected and for those versions, this configuration option is ignored.
616 config CC_STACKPROTECTOR_ALL
617 bool "Use stack-protector for all functions"
618 depends on CC_STACKPROTECTOR
620 Normally, GCC only inserts the canary value protection for
621 functions that use large-ish on-stack buffers. By enabling
622 this option, GCC will be asked to do this for ALL functions.
624 source kernel/Kconfig.hz
627 bool "Function reordering"
630 This option enables the toolchain to reorder functions for a more
631 optimal TLB usage. If you have pretty much any version of binutils,
632 this can increase your kernel build time by roughly one minute.
636 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
641 # Use the generic interrupt handling code in kernel/irq/:
643 config GENERIC_HARDIRQS
647 config GENERIC_IRQ_PROBE
651 # we have no ISA slots, but we do have ISA-style DMA.
656 config GENERIC_PENDING_IRQ
658 depends on GENERIC_HARDIRQS && SMP
661 menu "Power management options"
663 source kernel/power/Kconfig
665 source "drivers/acpi/Kconfig"
667 source "arch/x86_64/kernel/cpufreq/Kconfig"
671 menu "Bus options (PCI etc.)"
676 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
683 bool "Support mmconfig PCI config space access"
684 depends on PCI && ACPI
686 source "drivers/pci/pcie/Kconfig"
688 source "drivers/pci/Kconfig"
690 source "drivers/pcmcia/Kconfig"
692 source "drivers/pci/hotplug/Kconfig"
697 menu "Executable file formats / Emulations"
699 source "fs/Kconfig.binfmt"
701 config IA32_EMULATION
702 bool "IA32 Emulation"
704 Include code to run 32-bit programs under a 64-bit kernel. You should likely
705 turn this on, unless you're 100% sure that you don't have any 32-bit programs
709 tristate "IA32 a.out support"
710 depends on IA32_EMULATION
712 Support old a.out binaries in the 32bit emulation.
716 depends on IA32_EMULATION
719 config SYSVIPC_COMPAT
721 depends on COMPAT && SYSVIPC
728 source drivers/Kconfig
730 source "drivers/firmware/Kconfig"
734 menu "Instrumentation Support"
735 depends on EXPERIMENTAL
737 source "arch/x86_64/oprofile/Kconfig"
740 bool "Kprobes (EXPERIMENTAL)"
741 depends on KALLSYMS && EXPERIMENTAL && MODULES
743 Kprobes allows you to trap at almost any kernel address and
744 execute a callback function. register_kprobe() establishes
745 a probepoint and specifies the callback. Kprobes is useful
746 for kernel debugging, non-intrusive instrumentation and testing.
747 If in doubt, say "N".
750 source "arch/x86_64/Kconfig.debug"
752 source "security/Kconfig"
754 source "crypto/Kconfig"