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
88 config ARCH_POPULATES_NODE_MAP
102 menu "Processor type and features"
105 prompt "Subarchitecture Type"
111 Choose this option if your computer is a standard PC or compatible.
114 bool "Support for ScaleMP vSMP"
117 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
118 supposed to run on these EM64T-based machines. Only choose this option
119 if you have one of these machines.
124 prompt "Processor family"
128 bool "AMD-Opteron/Athlon64"
130 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
133 bool "Intel P4 / older Netburst based Xeon"
135 Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
136 with Intel Extended Memory 64 Technology(EM64T). For details see
137 <http://www.intel.com/technology/64bitextensions/>.
138 Note the the latest Xeons (Xeon 51xx and 53xx) are not based on the
139 Netburst core and shouldn't use this option. You can distingush them
140 using the cpu family field
141 in /proc/cpuinfo. Family 15 is a older Xeon, Family 6 a newer one
142 (this rule only applies to system that support EM64T)
145 bool "Intel Core2 / newer Xeon"
147 Optimize for Intel Core2 and newer Xeons (51xx)
148 You can distingush the newer Xeons from the older ones using
149 the cpu family field in /proc/cpuinfo. 15 is a older Xeon
150 (use CONFIG_MPSC then), 6 is a newer one. This rule only
151 applies to CPUs that support EM64T.
154 bool "Generic-x86-64"
157 Run equally well on all x86-64 CPUs.
162 # Define implied options from the CPU selection here
164 config X86_L1_CACHE_BYTES
166 default "128" if GENERIC_CPU || MPSC
167 default "64" if MK8 || MCORE2
169 config X86_L1_CACHE_SHIFT
171 default "7" if GENERIC_CPU || MPSC
172 default "6" if MK8 || MCORE2
174 config X86_INTERNODE_CACHE_BYTES
176 default "4096" if X86_VSMP
177 default X86_L1_CACHE_BYTES if !X86_VSMP
188 tristate "/dev/cpu/microcode - Intel CPU microcode support"
191 If you say Y here the 'File systems' section, you will be
192 able to update the microcode on Intel processors. You will
193 obviously need the actual microcode binary data itself which is
194 not shipped with the Linux kernel.
196 For latest news and information on obtaining all the required
197 ingredients for this driver, check:
198 <http://www.urbanmyth.org/microcode/>.
200 To compile this driver as a module, choose M here: the
201 module will be called microcode.
202 If you use modprobe or kmod you may also want to add the line
203 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
205 config MICROCODE_OLD_INTERFACE
211 tristate "/dev/cpu/*/msr - Model-specific register support"
213 This device gives privileged processes access to the x86
214 Model-Specific Registers (MSRs). It is a character device with
215 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
216 MSR accesses are directed to a specific CPU on multi-processor
220 tristate "/dev/cpu/*/cpuid - CPU information support"
222 This device gives processes access to the x86 CPUID instruction to
223 be executed on a specific processor. It is a character device
224 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
229 depends on SMP && !MK8
232 config MATH_EMULATION
245 config X86_LOCAL_APIC
250 bool "MTRR (Memory Type Range Register) support"
252 On Intel P6 family processors (Pentium Pro, Pentium II and later)
253 the Memory Type Range Registers (MTRRs) may be used to control
254 processor access to memory ranges. This is most useful if you have
255 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
256 allows bus write transfers to be combined into a larger transfer
257 before bursting over the PCI/AGP bus. This can increase performance
258 of image write operations 2.5 times or more. Saying Y here creates a
259 /proc/mtrr file which may be used to manipulate your processor's
260 MTRRs. Typically the X server should use this.
262 This code has a reasonably generic interface so that similar
263 control registers on other processors can be easily supported
266 Saying Y here also fixes a problem with buggy SMP BIOSes which only
267 set the MTRRs for the boot CPU and not for the secondary CPUs. This
268 can lead to all sorts of problems, so it's good to say Y here.
270 Just say Y here, all x86-64 machines support MTRRs.
272 See <file:Documentation/mtrr.txt> for more information.
275 bool "Symmetric multi-processing support"
277 This enables support for systems with more than one CPU. If you have
278 a system with only one CPU, like most personal computers, say N. If
279 you have a system with more than one CPU, say Y.
281 If you say N here, the kernel will run on single and multiprocessor
282 machines, but will use only one CPU of a multiprocessor machine. If
283 you say Y here, the kernel will run on many, but not all,
284 singleprocessor machines. On a singleprocessor machine, the kernel
285 will run faster if you say N here.
287 If you don't know what to do here, say N.
290 bool "SMT (Hyperthreading) scheduler support"
294 SMT scheduler support improves the CPU scheduler's decision making
295 when dealing with Intel Pentium 4 chips with HyperThreading at a
296 cost of slightly increased overhead in some places. If unsure say
300 bool "Multi-core scheduler support"
304 Multi-core scheduler support improves the CPU scheduler's decision
305 making when dealing with multi-core CPU chips at a cost of slightly
306 increased overhead in some places. If unsure say N here.
308 source "kernel/Kconfig.preempt"
311 bool "Non Uniform Memory Access (NUMA) Support"
314 Enable NUMA (Non Uniform Memory Access) support. The kernel
315 will try to allocate memory used by a CPU on the local memory
316 controller of the CPU and add some more NUMA awareness to the kernel.
317 This code is recommended on all multiprocessor Opteron systems.
318 If the system is EM64T, you should say N unless your system is EM64T
322 bool "Old style AMD Opteron NUMA detection"
323 depends on NUMA && PCI
326 Enable K8 NUMA node topology detection. You should say Y here if
327 you have a multi processor AMD K8 system. This uses an old
328 method to read the NUMA configuration directly from the builtin
329 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
330 instead, which also takes priority if both are compiled in.
335 depends on NEED_MULTIPLE_NODES
337 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
339 config X86_64_ACPI_NUMA
340 bool "ACPI NUMA detection"
347 Enable ACPI SRAT based node topology detection.
350 bool "NUMA emulation"
353 Enable NUMA emulation. A flat machine will be split
354 into virtual nodes when booted with "numa=fake=N", where N is the
355 number of nodes. This is only useful for debugging.
357 config ARCH_DISCONTIGMEM_ENABLE
362 config ARCH_DISCONTIGMEM_DEFAULT
366 config ARCH_SPARSEMEM_ENABLE
368 depends on (NUMA || EXPERIMENTAL)
370 config ARCH_MEMORY_PROBE
372 depends on MEMORY_HOTPLUG
374 config ARCH_FLATMEM_ENABLE
380 config MEMORY_HOTPLUG_RESERVE
382 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
384 config HAVE_ARCH_EARLY_PFN_TO_NID
388 config OUT_OF_LINE_PFN_TO_PAGE
390 depends on DISCONTIGMEM
393 int "Maximum number of CPUs (2-256)"
398 This allows you to specify the maximum number of CPUs which this
399 kernel will support. Current maximum is 256 CPUs due to
400 APIC addressing limits. Less depending on the hardware.
402 This is purely to save memory - each supported CPU requires
403 memory in the static kernel configuration.
406 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
407 depends on SMP && HOTPLUG && EXPERIMENTAL
409 Say Y here to experiment with turning CPUs off and on. CPUs
410 can be controlled through /sys/devices/system/cpu/cpu#.
411 Say N if you want to disable CPU hotplug.
413 config ARCH_ENABLE_MEMORY_HOTPLUG
420 Use the IA-PC HPET (High Precision Event Timer) to manage
421 time in preference to the PIT and RTC, if a HPET is
422 present. The HPET provides a stable time base on SMP
423 systems, unlike the TSC, but it is more expensive to access,
424 as it is off-chip. You can find the HPET spec at
425 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
427 config HPET_EMULATE_RTC
428 bool "Provide RTC interrupt"
429 depends on HPET_TIMER && RTC=y
431 # Mark as embedded because too many people got it wrong.
432 # The code disables itself when not needed.
434 bool "IOMMU support" if EMBEDDED
440 Support for full DMA access of devices with 32bit memory access only
441 on systems with more than 3GB. This is usually needed for USB,
442 sound, many IDE/SATA chipsets and some other devices.
443 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
444 based IOMMU and a software bounce buffer based IOMMU used on Intel
445 systems and as fallback.
446 The code is only active when needed (enough memory and limited
447 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
451 bool "IBM Calgary IOMMU support"
453 depends on PCI && EXPERIMENTAL
455 Support for hardware IOMMUs in IBM's xSeries x366 and x460
456 systems. Needed to run systems with more than 3GB of memory
457 properly with 32-bit PCI devices that do not support DAC
458 (Double Address Cycle). Calgary also supports bus level
459 isolation, where all DMAs pass through the IOMMU. This
460 prevents them from going anywhere except their intended
461 destination. This catches hard-to-find kernel bugs and
462 mis-behaving drivers and devices that do not use the DMA-API
463 properly to set up their DMA buffers. The IOMMU can be
464 turned off at boot time with the iommu=off parameter.
465 Normally the kernel will make the right choice by itself.
468 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
469 bool "Should Calgary be enabled by default?"
471 depends on CALGARY_IOMMU
473 Should Calgary be enabled by default? if you choose 'y', Calgary
474 will be used (if it exists). If you choose 'n', Calgary will not be
475 used even if it exists. If you choose 'n' and would like to use
476 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
479 # need this always selected by IOMMU for the VIA workaround
484 bool "Machine check support" if EMBEDDED
487 Include a machine check error handler to report hardware errors.
488 This version will require the mcelog utility to decode some
489 machine check error logs. See
490 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
493 bool "Intel MCE features"
494 depends on X86_MCE && X86_LOCAL_APIC
497 Additional support for intel specific MCE features such as
501 bool "AMD MCE features"
502 depends on X86_MCE && X86_LOCAL_APIC
505 Additional support for AMD specific MCE features such as
506 the DRAM Error Threshold.
509 bool "kexec system call"
511 kexec is a system call that implements the ability to shutdown your
512 current kernel, and to start another kernel. It is like a reboot
513 but it is independent of the system firmware. And like a reboot
514 you can start any kernel with it, not just Linux.
516 The name comes from the similarity to the exec system call.
518 It is an ongoing process to be certain the hardware in a machine
519 is properly shutdown, so do not be surprised if this code does not
520 initially work for you. It may help to enable device hotplugging
521 support. As of this writing the exact hardware interface is
522 strongly in flux, so no good recommendation can be made.
525 bool "kernel crash dumps (EXPERIMENTAL)"
526 depends on EXPERIMENTAL
528 Generate crash dump after being started by kexec.
529 This should be normally only set in special crash dump kernels
530 which are loaded in the main kernel with kexec-tools into
531 a specially reserved region and then later executed after
532 a crash by kdump/kexec. The crash dump kernel must be compiled
533 to a memory address not used by the main kernel or BIOS using
535 For more details see Documentation/kdump/kdump.txt
537 config PHYSICAL_START
538 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
539 default "0x1000000" if CRASH_DUMP
542 This gives the physical address where the kernel is loaded. Normally
543 for regular kernels this value is 0x200000 (2MB). But in the case
544 of kexec on panic the fail safe kernel needs to run at a different
545 address than the panic-ed kernel. This option is used to set the load
546 address for kernels used to capture crash dump on being kexec'ed
547 after panic. The default value for crash dump kernels is
548 0x1000000 (16MB). This can also be set based on the "X" value as
549 specified in the "crashkernel=YM@XM" command line boot parameter
550 passed to the panic-ed kernel. Typically this parameter is set as
551 crashkernel=64M@16M. Please take a look at
552 Documentation/kdump/kdump.txt for more details about crash dumps.
554 Don't change this unless you know what you are doing.
557 bool "Enable seccomp to safely compute untrusted bytecode"
561 This kernel feature is useful for number crunching applications
562 that may need to compute untrusted bytecode during their
563 execution. By using pipes or other transports made available to
564 the process as file descriptors supporting the read/write
565 syscalls, it's possible to isolate those applications in
566 their own address space using seccomp. Once seccomp is
567 enabled via /proc/<pid>/seccomp, it cannot be disabled
568 and the task is only allowed to execute a few safe syscalls
569 defined by each seccomp mode.
571 If unsure, say Y. Only embedded should say N here.
573 config CC_STACKPROTECTOR
574 bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
575 depends on EXPERIMENTAL
577 This option turns on the -fstack-protector GCC feature. This
578 feature puts, at the beginning of critical functions, a canary
579 value on the stack just before the return address, and validates
580 the value just before actually returning. Stack based buffer
581 overflows (that need to overwrite this return address) now also
582 overwrite the canary, which gets detected and the attack is then
583 neutralized via a kernel panic.
585 This feature requires gcc version 4.2 or above, or a distribution
586 gcc with the feature backported. Older versions are automatically
587 detected and for those versions, this configuration option is ignored.
589 config CC_STACKPROTECTOR_ALL
590 bool "Use stack-protector for all functions"
591 depends on CC_STACKPROTECTOR
593 Normally, GCC only inserts the canary value protection for
594 functions that use large-ish on-stack buffers. By enabling
595 this option, GCC will be asked to do this for ALL functions.
597 source kernel/Kconfig.hz
600 bool "Function reordering"
603 This option enables the toolchain to reorder functions for a more
604 optimal TLB usage. If you have pretty much any version of binutils,
605 this can increase your kernel build time by roughly one minute.
609 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
614 # Use the generic interrupt handling code in kernel/irq/:
616 config GENERIC_HARDIRQS
620 config GENERIC_IRQ_PROBE
624 # we have no ISA slots, but we do have ISA-style DMA.
629 config GENERIC_PENDING_IRQ
631 depends on GENERIC_HARDIRQS && SMP
634 menu "Power management options"
636 source kernel/power/Kconfig
638 source "drivers/acpi/Kconfig"
640 source "arch/x86_64/kernel/cpufreq/Kconfig"
644 menu "Bus options (PCI etc.)"
649 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
656 bool "Support mmconfig PCI config space access"
657 depends on PCI && ACPI
659 source "drivers/pci/pcie/Kconfig"
661 source "drivers/pci/Kconfig"
663 source "drivers/pcmcia/Kconfig"
665 source "drivers/pci/hotplug/Kconfig"
670 menu "Executable file formats / Emulations"
672 source "fs/Kconfig.binfmt"
674 config IA32_EMULATION
675 bool "IA32 Emulation"
677 Include code to run 32-bit programs under a 64-bit kernel. You should likely
678 turn this on, unless you're 100% sure that you don't have any 32-bit programs
682 tristate "IA32 a.out support"
683 depends on IA32_EMULATION
685 Support old a.out binaries in the 32bit emulation.
689 depends on IA32_EMULATION
692 config SYSVIPC_COMPAT
694 depends on COMPAT && SYSVIPC
701 source drivers/Kconfig
703 source "drivers/firmware/Kconfig"
707 menu "Instrumentation Support"
708 depends on EXPERIMENTAL
710 source "arch/x86_64/oprofile/Kconfig"
713 bool "Kprobes (EXPERIMENTAL)"
714 depends on KALLSYMS && EXPERIMENTAL && MODULES
716 Kprobes allows you to trap at almost any kernel address and
717 execute a callback function. register_kprobe() establishes
718 a probepoint and specifies the callback. Kprobes is useful
719 for kernel debugging, non-intrusive instrumentation and testing.
720 If in doubt, say "N".
723 source "arch/x86_64/Kconfig.debug"
725 source "security/Kconfig"
727 source "crypto/Kconfig"