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
363 config ARCH_DISCONTIGMEM_ENABLE
367 config ARCH_DISCONTIGMEM_DEFAULT
371 config ARCH_SPARSEMEM_ENABLE
373 depends on (NUMA || EXPERIMENTAL)
375 config ARCH_MEMORY_PROBE
377 depends on MEMORY_HOTPLUG
379 config ARCH_FLATMEM_ENABLE
385 config MEMORY_HOTPLUG_RESERVE
387 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
389 config HAVE_ARCH_EARLY_PFN_TO_NID
393 config OUT_OF_LINE_PFN_TO_PAGE
395 depends on DISCONTIGMEM
398 int "Maximum number of CPUs (2-256)"
403 This allows you to specify the maximum number of CPUs which this
404 kernel will support. Current maximum is 256 CPUs due to
405 APIC addressing limits. Less depending on the hardware.
407 This is purely to save memory - each supported CPU requires
408 memory in the static kernel configuration.
411 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
412 depends on SMP && HOTPLUG && EXPERIMENTAL
414 Say Y here to experiment with turning CPUs off and on. CPUs
415 can be controlled through /sys/devices/system/cpu/cpu#.
416 Say N if you want to disable CPU hotplug.
418 config ARCH_ENABLE_MEMORY_HOTPLUG
425 Use the IA-PC HPET (High Precision Event Timer) to manage
426 time in preference to the PIT and RTC, if a HPET is
427 present. The HPET provides a stable time base on SMP
428 systems, unlike the TSC, but it is more expensive to access,
429 as it is off-chip. You can find the HPET spec at
430 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
432 config HPET_EMULATE_RTC
433 bool "Provide RTC interrupt"
434 depends on HPET_TIMER && RTC=y
436 # Mark as embedded because too many people got it wrong.
437 # The code disables itself when not needed.
439 bool "IOMMU support" if EMBEDDED
445 Support for full DMA access of devices with 32bit memory access only
446 on systems with more than 3GB. This is usually needed for USB,
447 sound, many IDE/SATA chipsets and some other devices.
448 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
449 based IOMMU and a software bounce buffer based IOMMU used on Intel
450 systems and as fallback.
451 The code is only active when needed (enough memory and limited
452 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
456 bool "IBM Calgary IOMMU support"
458 depends on PCI && EXPERIMENTAL
460 Support for hardware IOMMUs in IBM's xSeries x366 and x460
461 systems. Needed to run systems with more than 3GB of memory
462 properly with 32-bit PCI devices that do not support DAC
463 (Double Address Cycle). Calgary also supports bus level
464 isolation, where all DMAs pass through the IOMMU. This
465 prevents them from going anywhere except their intended
466 destination. This catches hard-to-find kernel bugs and
467 mis-behaving drivers and devices that do not use the DMA-API
468 properly to set up their DMA buffers. The IOMMU can be
469 turned off at boot time with the iommu=off parameter.
470 Normally the kernel will make the right choice by itself.
473 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
474 bool "Should Calgary be enabled by default?"
476 depends on CALGARY_IOMMU
478 Should Calgary be enabled by default? if you choose 'y', Calgary
479 will be used (if it exists). If you choose 'n', Calgary will not be
480 used even if it exists. If you choose 'n' and would like to use
481 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
484 # need this always selected by IOMMU for the VIA workaround
489 bool "Machine check support" if EMBEDDED
492 Include a machine check error handler to report hardware errors.
493 This version will require the mcelog utility to decode some
494 machine check error logs. See
495 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
498 bool "Intel MCE features"
499 depends on X86_MCE && X86_LOCAL_APIC
502 Additional support for intel specific MCE features such as
506 bool "AMD MCE features"
507 depends on X86_MCE && X86_LOCAL_APIC
510 Additional support for AMD specific MCE features such as
511 the DRAM Error Threshold.
514 bool "kexec system call"
516 kexec is a system call that implements the ability to shutdown your
517 current kernel, and to start another kernel. It is like a reboot
518 but it is independent of the system firmware. And like a reboot
519 you can start any kernel with it, not just Linux.
521 The name comes from the similarity to the exec system call.
523 It is an ongoing process to be certain the hardware in a machine
524 is properly shutdown, so do not be surprised if this code does not
525 initially work for you. It may help to enable device hotplugging
526 support. As of this writing the exact hardware interface is
527 strongly in flux, so no good recommendation can be made.
530 bool "kernel crash dumps (EXPERIMENTAL)"
531 depends on EXPERIMENTAL
533 Generate crash dump after being started by kexec.
534 This should be normally only set in special crash dump kernels
535 which are loaded in the main kernel with kexec-tools into
536 a specially reserved region and then later executed after
537 a crash by kdump/kexec. The crash dump kernel must be compiled
538 to a memory address not used by the main kernel or BIOS using
540 For more details see Documentation/kdump/kdump.txt
542 config PHYSICAL_START
543 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
544 default "0x1000000" if CRASH_DUMP
547 This gives the physical address where the kernel is loaded. Normally
548 for regular kernels this value is 0x200000 (2MB). But in the case
549 of kexec on panic the fail safe kernel needs to run at a different
550 address than the panic-ed kernel. This option is used to set the load
551 address for kernels used to capture crash dump on being kexec'ed
552 after panic. The default value for crash dump kernels is
553 0x1000000 (16MB). This can also be set based on the "X" value as
554 specified in the "crashkernel=YM@XM" command line boot parameter
555 passed to the panic-ed kernel. Typically this parameter is set as
556 crashkernel=64M@16M. Please take a look at
557 Documentation/kdump/kdump.txt for more details about crash dumps.
559 Don't change this unless you know what you are doing.
562 bool "Enable seccomp to safely compute untrusted bytecode"
566 This kernel feature is useful for number crunching applications
567 that may need to compute untrusted bytecode during their
568 execution. By using pipes or other transports made available to
569 the process as file descriptors supporting the read/write
570 syscalls, it's possible to isolate those applications in
571 their own address space using seccomp. Once seccomp is
572 enabled via /proc/<pid>/seccomp, it cannot be disabled
573 and the task is only allowed to execute a few safe syscalls
574 defined by each seccomp mode.
576 If unsure, say Y. Only embedded should say N here.
578 config CC_STACKPROTECTOR
579 bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
580 depends on EXPERIMENTAL
582 This option turns on the -fstack-protector GCC feature. This
583 feature puts, at the beginning of critical functions, a canary
584 value on the stack just before the return address, and validates
585 the value just before actually returning. Stack based buffer
586 overflows (that need to overwrite this return address) now also
587 overwrite the canary, which gets detected and the attack is then
588 neutralized via a kernel panic.
590 This feature requires gcc version 4.2 or above, or a distribution
591 gcc with the feature backported. Older versions are automatically
592 detected and for those versions, this configuration option is ignored.
594 config CC_STACKPROTECTOR_ALL
595 bool "Use stack-protector for all functions"
596 depends on CC_STACKPROTECTOR
598 Normally, GCC only inserts the canary value protection for
599 functions that use large-ish on-stack buffers. By enabling
600 this option, GCC will be asked to do this for ALL functions.
602 source kernel/Kconfig.hz
605 bool "Function reordering"
608 This option enables the toolchain to reorder functions for a more
609 optimal TLB usage. If you have pretty much any version of binutils,
610 this can increase your kernel build time by roughly one minute.
614 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
619 # Use the generic interrupt handling code in kernel/irq/:
621 config GENERIC_HARDIRQS
625 config GENERIC_IRQ_PROBE
629 # we have no ISA slots, but we do have ISA-style DMA.
634 config GENERIC_PENDING_IRQ
636 depends on GENERIC_HARDIRQS && SMP
639 menu "Power management options"
641 source kernel/power/Kconfig
643 source "drivers/acpi/Kconfig"
645 source "arch/x86_64/kernel/cpufreq/Kconfig"
649 menu "Bus options (PCI etc.)"
654 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
661 bool "Support mmconfig PCI config space access"
662 depends on PCI && ACPI
664 source "drivers/pci/pcie/Kconfig"
666 source "drivers/pci/Kconfig"
668 source "drivers/pcmcia/Kconfig"
670 source "drivers/pci/hotplug/Kconfig"
675 menu "Executable file formats / Emulations"
677 source "fs/Kconfig.binfmt"
679 config IA32_EMULATION
680 bool "IA32 Emulation"
682 Include code to run 32-bit programs under a 64-bit kernel. You should likely
683 turn this on, unless you're 100% sure that you don't have any 32-bit programs
687 tristate "IA32 a.out support"
688 depends on IA32_EMULATION
690 Support old a.out binaries in the 32bit emulation.
694 depends on IA32_EMULATION
697 config SYSVIPC_COMPAT
699 depends on COMPAT && SYSVIPC
706 source drivers/Kconfig
708 source "drivers/firmware/Kconfig"
712 menu "Instrumentation Support"
713 depends on EXPERIMENTAL
715 source "arch/x86_64/oprofile/Kconfig"
718 bool "Kprobes (EXPERIMENTAL)"
719 depends on KALLSYMS && EXPERIMENTAL && MODULES
721 Kprobes allows you to trap at almost any kernel address and
722 execute a callback function. register_kprobe() establishes
723 a probepoint and specifies the callback. Kprobes is useful
724 for kernel debugging, non-intrusive instrumentation and testing.
725 If in doubt, say "N".
728 source "arch/x86_64/Kconfig.debug"
730 source "security/Kconfig"
732 source "crypto/Kconfig"