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.
135 Optimize for Intel Pentium 4 and Xeon CPUs with Intel
136 Extended Memory 64 Technology(EM64T). For details see
137 <http://www.intel.com/technology/64bitextensions/>.
140 bool "Generic-x86-64"
147 # Define implied options from the CPU selection here
149 config X86_L1_CACHE_BYTES
151 default "128" if GENERIC_CPU || MPSC
154 config X86_L1_CACHE_SHIFT
156 default "7" if GENERIC_CPU || MPSC
159 config X86_INTERNODE_CACHE_BYTES
161 default "4096" if X86_VSMP
162 default X86_L1_CACHE_BYTES if !X86_VSMP
173 tristate "/dev/cpu/microcode - Intel CPU microcode support"
175 If you say Y here the 'File systems' section, you will be
176 able to update the microcode on Intel processors. You will
177 obviously need the actual microcode binary data itself which is
178 not shipped with the Linux kernel.
180 For latest news and information on obtaining all the required
181 ingredients for this driver, check:
182 <http://www.urbanmyth.org/microcode/>.
184 To compile this driver as a module, choose M here: the
185 module will be called microcode.
186 If you use modprobe or kmod you may also want to add the line
187 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
190 tristate "/dev/cpu/*/msr - Model-specific register support"
192 This device gives privileged processes access to the x86
193 Model-Specific Registers (MSRs). It is a character device with
194 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
195 MSR accesses are directed to a specific CPU on multi-processor
199 tristate "/dev/cpu/*/cpuid - CPU information support"
201 This device gives processes access to the x86 CPUID instruction to
202 be executed on a specific processor. It is a character device
203 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
208 depends on SMP && !MK8
211 config MATH_EMULATION
224 config X86_LOCAL_APIC
229 bool "MTRR (Memory Type Range Register) support"
231 On Intel P6 family processors (Pentium Pro, Pentium II and later)
232 the Memory Type Range Registers (MTRRs) may be used to control
233 processor access to memory ranges. This is most useful if you have
234 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
235 allows bus write transfers to be combined into a larger transfer
236 before bursting over the PCI/AGP bus. This can increase performance
237 of image write operations 2.5 times or more. Saying Y here creates a
238 /proc/mtrr file which may be used to manipulate your processor's
239 MTRRs. Typically the X server should use this.
241 This code has a reasonably generic interface so that similar
242 control registers on other processors can be easily supported
245 Saying Y here also fixes a problem with buggy SMP BIOSes which only
246 set the MTRRs for the boot CPU and not for the secondary CPUs. This
247 can lead to all sorts of problems, so it's good to say Y here.
249 Just say Y here, all x86-64 machines support MTRRs.
251 See <file:Documentation/mtrr.txt> for more information.
254 bool "Symmetric multi-processing support"
256 This enables support for systems with more than one CPU. If you have
257 a system with only one CPU, like most personal computers, say N. If
258 you have a system with more than one CPU, say Y.
260 If you say N here, the kernel will run on single and multiprocessor
261 machines, but will use only one CPU of a multiprocessor machine. If
262 you say Y here, the kernel will run on many, but not all,
263 singleprocessor machines. On a singleprocessor machine, the kernel
264 will run faster if you say N here.
266 If you don't know what to do here, say N.
269 bool "SMT (Hyperthreading) scheduler support"
273 SMT scheduler support improves the CPU scheduler's decision making
274 when dealing with Intel Pentium 4 chips with HyperThreading at a
275 cost of slightly increased overhead in some places. If unsure say
279 bool "Multi-core scheduler support"
283 Multi-core scheduler support improves the CPU scheduler's decision
284 making when dealing with multi-core CPU chips at a cost of slightly
285 increased overhead in some places. If unsure say N here.
287 source "kernel/Kconfig.preempt"
290 bool "Non Uniform Memory Access (NUMA) Support"
293 Enable NUMA (Non Uniform Memory Access) support. The kernel
294 will try to allocate memory used by a CPU on the local memory
295 controller of the CPU and add some more NUMA awareness to the kernel.
296 This code is recommended on all multiprocessor Opteron systems.
297 If the system is EM64T, you should say N unless your system is EM64T
301 bool "Old style AMD Opteron NUMA detection"
302 depends on NUMA && PCI
305 Enable K8 NUMA node topology detection. You should say Y here if
306 you have a multi processor AMD K8 system. This uses an old
307 method to read the NUMA configurtion directly from the builtin
308 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
309 instead, which also takes priority if both are compiled in.
314 depends on NEED_MULTIPLE_NODES
316 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
318 config X86_64_ACPI_NUMA
319 bool "ACPI NUMA detection"
326 Enable ACPI SRAT based node topology detection.
329 bool "NUMA emulation"
332 Enable NUMA emulation. A flat machine will be split
333 into virtual nodes when booted with "numa=fake=N", where N is the
334 number of nodes. This is only useful for debugging.
336 config ARCH_DISCONTIGMEM_ENABLE
342 config ARCH_DISCONTIGMEM_ENABLE
346 config ARCH_DISCONTIGMEM_DEFAULT
350 config ARCH_SPARSEMEM_ENABLE
352 depends on (NUMA || EXPERIMENTAL)
354 config ARCH_MEMORY_PROBE
356 depends on MEMORY_HOTPLUG
358 config ARCH_FLATMEM_ENABLE
364 config HAVE_ARCH_EARLY_PFN_TO_NID
368 config OUT_OF_LINE_PFN_TO_PAGE
370 depends on DISCONTIGMEM
373 int "Maximum number of CPUs (2-256)"
378 This allows you to specify the maximum number of CPUs which this
379 kernel will support. Current maximum is 256 CPUs due to
380 APIC addressing limits. Less depending on the hardware.
382 This is purely to save memory - each supported CPU requires
383 memory in the static kernel configuration.
386 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
387 depends on SMP && HOTPLUG && EXPERIMENTAL
389 Say Y here to experiment with turning CPUs off and on. CPUs
390 can be controlled through /sys/devices/system/cpu/cpu#.
391 Say N if you want to disable CPU hotplug.
393 config ARCH_ENABLE_MEMORY_HOTPLUG
400 Use the IA-PC HPET (High Precision Event Timer) to manage
401 time in preference to the PIT and RTC, if a HPET is
402 present. The HPET provides a stable time base on SMP
403 systems, unlike the TSC, but it is more expensive to access,
404 as it is off-chip. You can find the HPET spec at
405 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
407 config HPET_EMULATE_RTC
408 bool "Provide RTC interrupt"
409 depends on HPET_TIMER && RTC=y
411 # Mark as embedded because too many people got it wrong.
412 # The code disables itself when not needed.
414 bool "IOMMU support" if EMBEDDED
420 Support for full DMA access of devices with 32bit memory access only
421 on systems with more than 3GB. This is usually needed for USB,
422 sound, many IDE/SATA chipsets and some other devices.
423 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
424 based IOMMU and a software bounce buffer based IOMMU used on Intel
425 systems and as fallback.
426 The code is only active when needed (enough memory and limited
427 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
431 bool "IBM Calgary IOMMU support"
433 depends on PCI && EXPERIMENTAL
435 Support for hardware IOMMUs in IBM's xSeries x366 and x460
436 systems. Needed to run systems with more than 3GB of memory
437 properly with 32-bit PCI devices that do not support DAC
438 (Double Address Cycle). Calgary also supports bus level
439 isolation, where all DMAs pass through the IOMMU. This
440 prevents them from going anywhere except their intended
441 destination. This catches hard-to-find kernel bugs and
442 mis-behaving drivers and devices that do not use the DMA-API
443 properly to set up their DMA buffers. The IOMMU can be
444 turned off at boot time with the iommu=off parameter.
445 Normally the kernel will make the right choice by itself.
448 # need this always selected by IOMMU for the VIA workaround
453 bool "Machine check support" if EMBEDDED
456 Include a machine check error handler to report hardware errors.
457 This version will require the mcelog utility to decode some
458 machine check error logs. See
459 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
462 bool "Intel MCE features"
463 depends on X86_MCE && X86_LOCAL_APIC
466 Additional support for intel specific MCE features such as
470 bool "AMD MCE features"
471 depends on X86_MCE && X86_LOCAL_APIC
474 Additional support for AMD specific MCE features such as
475 the DRAM Error Threshold.
478 bool "kexec system call"
480 kexec is a system call that implements the ability to shutdown your
481 current kernel, and to start another kernel. It is like a reboot
482 but it is independent of the system firmware. And like a reboot
483 you can start any kernel with it, not just Linux.
485 The name comes from the similarity to the exec system call.
487 It is an ongoing process to be certain the hardware in a machine
488 is properly shutdown, so do not be surprised if this code does not
489 initially work for you. It may help to enable device hotplugging
490 support. As of this writing the exact hardware interface is
491 strongly in flux, so no good recommendation can be made.
494 bool "kernel crash dumps (EXPERIMENTAL)"
495 depends on EXPERIMENTAL
497 Generate crash dump after being started by kexec.
498 This should be normally only set in special crash dump kernels
499 which are loaded in the main kernel with kexec-tools into
500 a specially reserved region and then later executed after
501 a crash by kdump/kexec. The crash dump kernel must be compiled
502 to a memory address not used by the main kernel or BIOS using
504 For more details see Documentation/kdump/kdump.txt
506 config PHYSICAL_START
507 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
508 default "0x1000000" if CRASH_DUMP
511 This gives the physical address where the kernel is loaded. Normally
512 for regular kernels this value is 0x200000 (2MB). But in the case
513 of kexec on panic the fail safe kernel needs to run at a different
514 address than the panic-ed kernel. This option is used to set the load
515 address for kernels used to capture crash dump on being kexec'ed
516 after panic. The default value for crash dump kernels is
517 0x1000000 (16MB). This can also be set based on the "X" value as
518 specified in the "crashkernel=YM@XM" command line boot parameter
519 passed to the panic-ed kernel. Typically this parameter is set as
520 crashkernel=64M@16M. Please take a look at
521 Documentation/kdump/kdump.txt for more details about crash dumps.
523 Don't change this unless you know what you are doing.
526 bool "Enable seccomp to safely compute untrusted bytecode"
530 This kernel feature is useful for number crunching applications
531 that may need to compute untrusted bytecode during their
532 execution. By using pipes or other transports made available to
533 the process as file descriptors supporting the read/write
534 syscalls, it's possible to isolate those applications in
535 their own address space using seccomp. Once seccomp is
536 enabled via /proc/<pid>/seccomp, it cannot be disabled
537 and the task is only allowed to execute a few safe syscalls
538 defined by each seccomp mode.
540 If unsure, say Y. Only embedded should say N here.
542 config CC_STACKPROTECTOR
543 bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
544 depends on EXPERIMENTAL
546 This option turns on the -fstack-protector GCC feature. This
547 feature puts, at the beginning of critical functions, a canary
548 value on the stack just before the return address, and validates
549 the value just before actually returning. Stack based buffer
550 overflows (that need to overwrite this return address) now also
551 overwrite the canary, which gets detected and the attack is then
552 neutralized via a kernel panic.
554 This feature requires gcc version 4.2 or above, or a distribution
555 gcc with the feature backported. Older versions are automatically
556 detected and for those versions, this configuration option is ignored.
558 config CC_STACKPROTECTOR_ALL
559 bool "Use stack-protector for all functions"
560 depends on CC_STACKPROTECTOR
562 Normally, GCC only inserts the canary value protection for
563 functions that use large-ish on-stack buffers. By enabling
564 this option, GCC will be asked to do this for ALL functions.
566 source kernel/Kconfig.hz
569 bool "Function reordering"
572 This option enables the toolchain to reorder functions for a more
573 optimal TLB usage. If you have pretty much any version of binutils,
574 this can increase your kernel build time by roughly one minute.
578 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
583 # Use the generic interrupt handling code in kernel/irq/:
585 config GENERIC_HARDIRQS
589 config GENERIC_IRQ_PROBE
593 # we have no ISA slots, but we do have ISA-style DMA.
598 config GENERIC_PENDING_IRQ
600 depends on GENERIC_HARDIRQS && SMP
603 menu "Power management options"
605 source kernel/power/Kconfig
607 source "drivers/acpi/Kconfig"
609 source "arch/x86_64/kernel/cpufreq/Kconfig"
613 menu "Bus options (PCI etc.)"
618 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
625 bool "Support mmconfig PCI config space access"
626 depends on PCI && ACPI
628 source "drivers/pci/pcie/Kconfig"
630 source "drivers/pci/Kconfig"
632 source "drivers/pcmcia/Kconfig"
634 source "drivers/pci/hotplug/Kconfig"
639 menu "Executable file formats / Emulations"
641 source "fs/Kconfig.binfmt"
643 config IA32_EMULATION
644 bool "IA32 Emulation"
646 Include code to run 32-bit programs under a 64-bit kernel. You should likely
647 turn this on, unless you're 100% sure that you don't have any 32-bit programs
651 tristate "IA32 a.out support"
652 depends on IA32_EMULATION
654 Support old a.out binaries in the 32bit emulation.
658 depends on IA32_EMULATION
661 config SYSVIPC_COMPAT
663 depends on COMPAT && SYSVIPC
670 source drivers/Kconfig
672 source "drivers/firmware/Kconfig"
676 menu "Instrumentation Support"
677 depends on EXPERIMENTAL
679 source "arch/x86_64/oprofile/Kconfig"
682 bool "Kprobes (EXPERIMENTAL)"
683 depends on EXPERIMENTAL && MODULES
685 Kprobes allows you to trap at almost any kernel address and
686 execute a callback function. register_kprobe() establishes
687 a probepoint and specifies the callback. Kprobes is useful
688 for kernel debugging, non-intrusive instrumentation and testing.
689 If in doubt, say "N".
692 source "arch/x86_64/Kconfig.debug"
694 source "security/Kconfig"
696 source "crypto/Kconfig"