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 LOCKDEP_SUPPORT
35 config STACKTRACE_SUPPORT
39 config SEMAPHORE_SLEEPERS
53 config RWSEM_GENERIC_SPINLOCK
57 config RWSEM_XCHGADD_ALGORITHM
60 config GENERIC_HWEIGHT
64 config GENERIC_CALIBRATE_DELAY
76 config GENERIC_ISA_DMA
84 config ARCH_MAY_HAVE_PC_FDC
99 menu "Processor type and features"
102 prompt "Subarchitecture Type"
108 Choose this option if your computer is a standard PC or compatible.
111 bool "Support for ScaleMP vSMP"
114 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
115 supposed to run on these EM64T-based machines. Only choose this option
116 if you have one of these machines.
121 prompt "Processor family"
125 bool "AMD-Opteron/Athlon64"
127 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
132 Optimize for Intel Pentium 4 and Xeon CPUs with Intel
133 Extended Memory 64 Technology(EM64T). For details see
134 <http://www.intel.com/technology/64bitextensions/>.
137 bool "Generic-x86-64"
144 # Define implied options from the CPU selection here
146 config X86_L1_CACHE_BYTES
148 default "128" if GENERIC_CPU || MPSC
151 config X86_L1_CACHE_SHIFT
153 default "7" if GENERIC_CPU || MPSC
156 config X86_INTERNODE_CACHE_BYTES
158 default "4096" if X86_VSMP
159 default X86_L1_CACHE_BYTES if !X86_VSMP
170 tristate "/dev/cpu/microcode - Intel CPU microcode support"
172 If you say Y here the 'File systems' section, you will be
173 able to update the microcode on Intel processors. You will
174 obviously need the actual microcode binary data itself which is
175 not shipped with the Linux kernel.
177 For latest news and information on obtaining all the required
178 ingredients for this driver, check:
179 <http://www.urbanmyth.org/microcode/>.
181 To compile this driver as a module, choose M here: the
182 module will be called microcode.
183 If you use modprobe or kmod you may also want to add the line
184 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
187 tristate "/dev/cpu/*/msr - Model-specific register support"
189 This device gives privileged processes access to the x86
190 Model-Specific Registers (MSRs). It is a character device with
191 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
192 MSR accesses are directed to a specific CPU on multi-processor
196 tristate "/dev/cpu/*/cpuid - CPU information support"
198 This device gives processes access to the x86 CPUID instruction to
199 be executed on a specific processor. It is a character device
200 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
205 depends on SMP && !MK8
208 config MATH_EMULATION
221 config X86_LOCAL_APIC
226 bool "MTRR (Memory Type Range Register) support"
228 On Intel P6 family processors (Pentium Pro, Pentium II and later)
229 the Memory Type Range Registers (MTRRs) may be used to control
230 processor access to memory ranges. This is most useful if you have
231 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
232 allows bus write transfers to be combined into a larger transfer
233 before bursting over the PCI/AGP bus. This can increase performance
234 of image write operations 2.5 times or more. Saying Y here creates a
235 /proc/mtrr file which may be used to manipulate your processor's
236 MTRRs. Typically the X server should use this.
238 This code has a reasonably generic interface so that similar
239 control registers on other processors can be easily supported
242 Saying Y here also fixes a problem with buggy SMP BIOSes which only
243 set the MTRRs for the boot CPU and not for the secondary CPUs. This
244 can lead to all sorts of problems, so it's good to say Y here.
246 Just say Y here, all x86-64 machines support MTRRs.
248 See <file:Documentation/mtrr.txt> for more information.
251 bool "Symmetric multi-processing support"
253 This enables support for systems with more than one CPU. If you have
254 a system with only one CPU, like most personal computers, say N. If
255 you have a system with more than one CPU, say Y.
257 If you say N here, the kernel will run on single and multiprocessor
258 machines, but will use only one CPU of a multiprocessor machine. If
259 you say Y here, the kernel will run on many, but not all,
260 singleprocessor machines. On a singleprocessor machine, the kernel
261 will run faster if you say N here.
263 If you don't know what to do here, say N.
266 bool "SMT (Hyperthreading) scheduler support"
270 SMT scheduler support improves the CPU scheduler's decision making
271 when dealing with Intel Pentium 4 chips with HyperThreading at a
272 cost of slightly increased overhead in some places. If unsure say
276 bool "Multi-core scheduler support"
280 Multi-core scheduler support improves the CPU scheduler's decision
281 making when dealing with multi-core CPU chips at a cost of slightly
282 increased overhead in some places. If unsure say N here.
284 source "kernel/Kconfig.preempt"
287 bool "Non Uniform Memory Access (NUMA) Support"
290 Enable NUMA (Non Uniform Memory Access) support. The kernel
291 will try to allocate memory used by a CPU on the local memory
292 controller of the CPU and add some more NUMA awareness to the kernel.
293 This code is recommended on all multiprocessor Opteron systems.
294 If the system is EM64T, you should say N unless your system is EM64T
298 bool "Old style AMD Opteron NUMA detection"
299 depends on NUMA && PCI
302 Enable K8 NUMA node topology detection. You should say Y here if
303 you have a multi processor AMD K8 system. This uses an old
304 method to read the NUMA configurtion directly from the builtin
305 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
306 instead, which also takes priority if both are compiled in.
311 depends on NEED_MULTIPLE_NODES
313 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
315 config X86_64_ACPI_NUMA
316 bool "ACPI NUMA detection"
323 Enable ACPI SRAT based node topology detection.
326 bool "NUMA emulation"
329 Enable NUMA emulation. A flat machine will be split
330 into virtual nodes when booted with "numa=fake=N", where N is the
331 number of nodes. This is only useful for debugging.
333 config ARCH_DISCONTIGMEM_ENABLE
339 config ARCH_DISCONTIGMEM_ENABLE
343 config ARCH_DISCONTIGMEM_DEFAULT
347 config ARCH_SPARSEMEM_ENABLE
349 depends on (NUMA || EXPERIMENTAL)
351 config ARCH_MEMORY_PROBE
353 depends on MEMORY_HOTPLUG
355 config ARCH_FLATMEM_ENABLE
361 config HAVE_ARCH_EARLY_PFN_TO_NID
365 config OUT_OF_LINE_PFN_TO_PAGE
367 depends on DISCONTIGMEM
370 int "Maximum number of CPUs (2-256)"
375 This allows you to specify the maximum number of CPUs which this
376 kernel will support. Current maximum is 256 CPUs due to
377 APIC addressing limits. Less depending on the hardware.
379 This is purely to save memory - each supported CPU requires
380 memory in the static kernel configuration.
383 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
384 depends on SMP && HOTPLUG && EXPERIMENTAL
386 Say Y here to experiment with turning CPUs off and on. CPUs
387 can be controlled through /sys/devices/system/cpu/cpu#.
388 Say N if you want to disable CPU hotplug.
390 config ARCH_ENABLE_MEMORY_HOTPLUG
397 Use the IA-PC HPET (High Precision Event Timer) to manage
398 time in preference to the PIT and RTC, if a HPET is
399 present. The HPET provides a stable time base on SMP
400 systems, unlike the TSC, but it is more expensive to access,
401 as it is off-chip. You can find the HPET spec at
402 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
404 config HPET_EMULATE_RTC
405 bool "Provide RTC interrupt"
406 depends on HPET_TIMER && RTC=y
408 # Mark as embedded because too many people got it wrong.
409 # The code disables itself when not needed.
411 bool "IOMMU support" if EMBEDDED
417 Support for full DMA access of devices with 32bit memory access only
418 on systems with more than 3GB. This is usually needed for USB,
419 sound, many IDE/SATA chipsets and some other devices.
420 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
421 based IOMMU and a software bounce buffer based IOMMU used on Intel
422 systems and as fallback.
423 The code is only active when needed (enough memory and limited
424 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
428 bool "IBM Calgary IOMMU support"
430 depends on PCI && EXPERIMENTAL
432 Support for hardware IOMMUs in IBM's xSeries x366 and x460
433 systems. Needed to run systems with more than 3GB of memory
434 properly with 32-bit PCI devices that do not support DAC
435 (Double Address Cycle). Calgary also supports bus level
436 isolation, where all DMAs pass through the IOMMU. This
437 prevents them from going anywhere except their intended
438 destination. This catches hard-to-find kernel bugs and
439 mis-behaving drivers and devices that do not use the DMA-API
440 properly to set up their DMA buffers. The IOMMU can be
441 turned off at boot time with the iommu=off parameter.
442 Normally the kernel will make the right choice by itself.
445 # need this always selected by IOMMU for the VIA workaround
450 bool "Machine check support" if EMBEDDED
453 Include a machine check error handler to report hardware errors.
454 This version will require the mcelog utility to decode some
455 machine check error logs. See
456 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
459 bool "Intel MCE features"
460 depends on X86_MCE && X86_LOCAL_APIC
463 Additional support for intel specific MCE features such as
467 bool "AMD MCE features"
468 depends on X86_MCE && X86_LOCAL_APIC
471 Additional support for AMD specific MCE features such as
472 the DRAM Error Threshold.
475 bool "kexec system call"
477 kexec is a system call that implements the ability to shutdown your
478 current kernel, and to start another kernel. It is like a reboot
479 but it is independent of the system firmware. And like a reboot
480 you can start any kernel with it, not just Linux.
482 The name comes from the similarity to the exec system call.
484 It is an ongoing process to be certain the hardware in a machine
485 is properly shutdown, so do not be surprised if this code does not
486 initially work for you. It may help to enable device hotplugging
487 support. As of this writing the exact hardware interface is
488 strongly in flux, so no good recommendation can be made.
491 bool "kernel crash dumps (EXPERIMENTAL)"
492 depends on EXPERIMENTAL
494 Generate crash dump after being started by kexec.
495 This should be normally only set in special crash dump kernels
496 which are loaded in the main kernel with kexec-tools into
497 a specially reserved region and then later executed after
498 a crash by kdump/kexec. The crash dump kernel must be compiled
499 to a memory address not used by the main kernel or BIOS using
501 For more details see Documentation/kdump/kdump.txt
503 config PHYSICAL_START
504 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
505 default "0x1000000" if CRASH_DUMP
508 This gives the physical address where the kernel is loaded. Normally
509 for regular kernels this value is 0x200000 (2MB). But in the case
510 of kexec on panic the fail safe kernel needs to run at a different
511 address than the panic-ed kernel. This option is used to set the load
512 address for kernels used to capture crash dump on being kexec'ed
513 after panic. The default value for crash dump kernels is
514 0x1000000 (16MB). This can also be set based on the "X" value as
515 specified in the "crashkernel=YM@XM" command line boot parameter
516 passed to the panic-ed kernel. Typically this parameter is set as
517 crashkernel=64M@16M. Please take a look at
518 Documentation/kdump/kdump.txt for more details about crash dumps.
520 Don't change this unless you know what you are doing.
523 bool "Enable seccomp to safely compute untrusted bytecode"
527 This kernel feature is useful for number crunching applications
528 that may need to compute untrusted bytecode during their
529 execution. By using pipes or other transports made available to
530 the process as file descriptors supporting the read/write
531 syscalls, it's possible to isolate those applications in
532 their own address space using seccomp. Once seccomp is
533 enabled via /proc/<pid>/seccomp, it cannot be disabled
534 and the task is only allowed to execute a few safe syscalls
535 defined by each seccomp mode.
537 If unsure, say Y. Only embedded should say N here.
539 config CC_STACKPROTECTOR
540 bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
541 depends on EXPERIMENTAL
543 This option turns on the -fstack-protector GCC feature. This
544 feature puts, at the beginning of critical functions, a canary
545 value on the stack just before the return address, and validates
546 the value just before actually returning. Stack based buffer
547 overflows (that need to overwrite this return address) now also
548 overwrite the canary, which gets detected and the attack is then
549 neutralized via a kernel panic.
551 This feature requires gcc version 4.2 or above, or a distribution
552 gcc with the feature backported. Older versions are automatically
553 detected and for those versions, this configuration option is ignored.
555 config CC_STACKPROTECTOR_ALL
556 bool "Use stack-protector for all functions"
557 depends on CC_STACKPROTECTOR
559 Normally, GCC only inserts the canary value protection for
560 functions that use large-ish on-stack buffers. By enabling
561 this option, GCC will be asked to do this for ALL functions.
563 source kernel/Kconfig.hz
566 bool "Function reordering"
569 This option enables the toolchain to reorder functions for a more
570 optimal TLB usage. If you have pretty much any version of binutils,
571 this can increase your kernel build time by roughly one minute.
575 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
580 # Use the generic interrupt handling code in kernel/irq/:
582 config GENERIC_HARDIRQS
586 config GENERIC_IRQ_PROBE
590 # we have no ISA slots, but we do have ISA-style DMA.
595 config GENERIC_PENDING_IRQ
597 depends on GENERIC_HARDIRQS && SMP
600 menu "Power management options"
602 source kernel/power/Kconfig
604 source "drivers/acpi/Kconfig"
606 source "arch/x86_64/kernel/cpufreq/Kconfig"
610 menu "Bus options (PCI etc.)"
615 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
622 bool "Support mmconfig PCI config space access"
623 depends on PCI && ACPI
625 source "drivers/pci/pcie/Kconfig"
627 source "drivers/pci/Kconfig"
629 source "drivers/pcmcia/Kconfig"
631 source "drivers/pci/hotplug/Kconfig"
636 menu "Executable file formats / Emulations"
638 source "fs/Kconfig.binfmt"
640 config IA32_EMULATION
641 bool "IA32 Emulation"
643 Include code to run 32-bit programs under a 64-bit kernel. You should likely
644 turn this on, unless you're 100% sure that you don't have any 32-bit programs
648 tristate "IA32 a.out support"
649 depends on IA32_EMULATION
651 Support old a.out binaries in the 32bit emulation.
655 depends on IA32_EMULATION
658 config SYSVIPC_COMPAT
660 depends on COMPAT && SYSVIPC
667 source drivers/Kconfig
669 source "drivers/firmware/Kconfig"
673 menu "Instrumentation Support"
674 depends on EXPERIMENTAL
676 source "arch/x86_64/oprofile/Kconfig"
679 bool "Kprobes (EXPERIMENTAL)"
680 depends on EXPERIMENTAL && MODULES
682 Kprobes allows you to trap at almost any kernel address and
683 execute a callback function. register_kprobe() establishes
684 a probepoint and specifies the callback. Kprobes is useful
685 for kernel debugging, non-intrusive instrumentation and testing.
686 If in doubt, say "N".
689 source "arch/x86_64/Kconfig.debug"
691 source "security/Kconfig"
693 source "crypto/Kconfig"