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/>.
27 config LOCKDEP_SUPPORT
31 config STACKTRACE_SUPPORT
35 config SEMAPHORE_SLEEPERS
49 config RWSEM_GENERIC_SPINLOCK
53 config RWSEM_XCHGADD_ALGORITHM
56 config GENERIC_HWEIGHT
60 config GENERIC_CALIBRATE_DELAY
72 config GENERIC_ISA_DMA
80 config ARCH_MAY_HAVE_PC_FDC
95 menu "Processor type and features"
98 prompt "Subarchitecture Type"
104 Choose this option if your computer is a standard PC or compatible.
107 bool "Support for ScaleMP vSMP"
110 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
111 supposed to run on these EM64T-based machines. Only choose this option
112 if you have one of these machines.
117 prompt "Processor family"
121 bool "AMD-Opteron/Athlon64"
123 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
128 Optimize for Intel Pentium 4 and Xeon CPUs with Intel
129 Extended Memory 64 Technology(EM64T). For details see
130 <http://www.intel.com/technology/64bitextensions/>.
133 bool "Generic-x86-64"
140 # Define implied options from the CPU selection here
142 config X86_L1_CACHE_BYTES
144 default "128" if GENERIC_CPU || MPSC
147 config X86_L1_CACHE_SHIFT
149 default "7" if GENERIC_CPU || MPSC
152 config X86_INTERNODE_CACHE_BYTES
154 default "4096" if X86_VSMP
155 default X86_L1_CACHE_BYTES if !X86_VSMP
166 tristate "/dev/cpu/microcode - Intel CPU microcode support"
168 If you say Y here the 'File systems' section, you will be
169 able to update the microcode on Intel processors. You will
170 obviously need the actual microcode binary data itself which is
171 not shipped with the Linux kernel.
173 For latest news and information on obtaining all the required
174 ingredients for this driver, check:
175 <http://www.urbanmyth.org/microcode/>.
177 To compile this driver as a module, choose M here: the
178 module will be called microcode.
179 If you use modprobe or kmod you may also want to add the line
180 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
183 tristate "/dev/cpu/*/msr - Model-specific register support"
185 This device gives privileged processes access to the x86
186 Model-Specific Registers (MSRs). It is a character device with
187 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
188 MSR accesses are directed to a specific CPU on multi-processor
192 tristate "/dev/cpu/*/cpuid - CPU information support"
194 This device gives processes access to the x86 CPUID instruction to
195 be executed on a specific processor. It is a character device
196 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
201 depends on SMP && !MK8
204 config MATH_EMULATION
217 config X86_LOCAL_APIC
222 bool "MTRR (Memory Type Range Register) support"
224 On Intel P6 family processors (Pentium Pro, Pentium II and later)
225 the Memory Type Range Registers (MTRRs) may be used to control
226 processor access to memory ranges. This is most useful if you have
227 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
228 allows bus write transfers to be combined into a larger transfer
229 before bursting over the PCI/AGP bus. This can increase performance
230 of image write operations 2.5 times or more. Saying Y here creates a
231 /proc/mtrr file which may be used to manipulate your processor's
232 MTRRs. Typically the X server should use this.
234 This code has a reasonably generic interface so that similar
235 control registers on other processors can be easily supported
238 Saying Y here also fixes a problem with buggy SMP BIOSes which only
239 set the MTRRs for the boot CPU and not for the secondary CPUs. This
240 can lead to all sorts of problems, so it's good to say Y here.
242 Just say Y here, all x86-64 machines support MTRRs.
244 See <file:Documentation/mtrr.txt> for more information.
247 bool "Symmetric multi-processing support"
249 This enables support for systems with more than one CPU. If you have
250 a system with only one CPU, like most personal computers, say N. If
251 you have a system with more than one CPU, say Y.
253 If you say N here, the kernel will run on single and multiprocessor
254 machines, but will use only one CPU of a multiprocessor machine. If
255 you say Y here, the kernel will run on many, but not all,
256 singleprocessor machines. On a singleprocessor machine, the kernel
257 will run faster if you say N here.
259 If you don't know what to do here, say N.
262 bool "SMT (Hyperthreading) scheduler support"
266 SMT scheduler support improves the CPU scheduler's decision making
267 when dealing with Intel Pentium 4 chips with HyperThreading at a
268 cost of slightly increased overhead in some places. If unsure say
272 bool "Multi-core scheduler support"
276 Multi-core scheduler support improves the CPU scheduler's decision
277 making when dealing with multi-core CPU chips at a cost of slightly
278 increased overhead in some places. If unsure say N here.
280 source "kernel/Kconfig.preempt"
283 bool "Non Uniform Memory Access (NUMA) Support"
286 Enable NUMA (Non Uniform Memory Access) support. The kernel
287 will try to allocate memory used by a CPU on the local memory
288 controller of the CPU and add some more NUMA awareness to the kernel.
289 This code is recommended on all multiprocessor Opteron systems.
290 If the system is EM64T, you should say N unless your system is EM64T
294 bool "Old style AMD Opteron NUMA detection"
295 depends on NUMA && PCI
298 Enable K8 NUMA node topology detection. You should say Y here if
299 you have a multi processor AMD K8 system. This uses an old
300 method to read the NUMA configurtion directly from the builtin
301 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
302 instead, which also takes priority if both are compiled in.
307 depends on NEED_MULTIPLE_NODES
309 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
311 config X86_64_ACPI_NUMA
312 bool "ACPI NUMA detection"
319 Enable ACPI SRAT based node topology detection.
322 bool "NUMA emulation"
325 Enable NUMA emulation. A flat machine will be split
326 into virtual nodes when booted with "numa=fake=N", where N is the
327 number of nodes. This is only useful for debugging.
329 config ARCH_DISCONTIGMEM_ENABLE
335 config ARCH_DISCONTIGMEM_ENABLE
339 config ARCH_DISCONTIGMEM_DEFAULT
343 config ARCH_SPARSEMEM_ENABLE
345 depends on (NUMA || EXPERIMENTAL)
347 config ARCH_MEMORY_PROBE
349 depends on MEMORY_HOTPLUG
351 config ARCH_FLATMEM_ENABLE
357 config HAVE_ARCH_EARLY_PFN_TO_NID
361 config OUT_OF_LINE_PFN_TO_PAGE
363 depends on DISCONTIGMEM
366 int "Maximum number of CPUs (2-256)"
371 This allows you to specify the maximum number of CPUs which this
372 kernel will support. Current maximum is 256 CPUs due to
373 APIC addressing limits. Less depending on the hardware.
375 This is purely to save memory - each supported CPU requires
376 memory in the static kernel configuration.
379 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
380 depends on SMP && HOTPLUG && EXPERIMENTAL
382 Say Y here to experiment with turning CPUs off and on. CPUs
383 can be controlled through /sys/devices/system/cpu/cpu#.
384 Say N if you want to disable CPU hotplug.
386 config ARCH_ENABLE_MEMORY_HOTPLUG
393 Use the IA-PC HPET (High Precision Event Timer) to manage
394 time in preference to the PIT and RTC, if a HPET is
395 present. The HPET provides a stable time base on SMP
396 systems, unlike the TSC, but it is more expensive to access,
397 as it is off-chip. You can find the HPET spec at
398 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
400 config HPET_EMULATE_RTC
401 bool "Provide RTC interrupt"
402 depends on HPET_TIMER && RTC=y
404 # Mark as embedded because too many people got it wrong.
405 # The code disables itself when not needed.
407 bool "IOMMU support" if EMBEDDED
413 Support for full DMA access of devices with 32bit memory access only
414 on systems with more than 3GB. This is usually needed for USB,
415 sound, many IDE/SATA chipsets and some other devices.
416 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
417 based IOMMU and a software bounce buffer based IOMMU used on Intel
418 systems and as fallback.
419 The code is only active when needed (enough memory and limited
420 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
424 bool "IBM Calgary IOMMU support"
426 depends on PCI && EXPERIMENTAL
428 Support for hardware IOMMUs in IBM's xSeries x366 and x460
429 systems. Needed to run systems with more than 3GB of memory
430 properly with 32-bit PCI devices that do not support DAC
431 (Double Address Cycle). Calgary also supports bus level
432 isolation, where all DMAs pass through the IOMMU. This
433 prevents them from going anywhere except their intended
434 destination. This catches hard-to-find kernel bugs and
435 mis-behaving drivers and devices that do not use the DMA-API
436 properly to set up their DMA buffers. The IOMMU can be
437 turned off at boot time with the iommu=off parameter.
438 Normally the kernel will make the right choice by itself.
441 # need this always selected by IOMMU for the VIA workaround
446 bool "Machine check support" if EMBEDDED
449 Include a machine check error handler to report hardware errors.
450 This version will require the mcelog utility to decode some
451 machine check error logs. See
452 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
455 bool "Intel MCE features"
456 depends on X86_MCE && X86_LOCAL_APIC
459 Additional support for intel specific MCE features such as
463 bool "AMD MCE features"
464 depends on X86_MCE && X86_LOCAL_APIC
467 Additional support for AMD specific MCE features such as
468 the DRAM Error Threshold.
471 bool "kexec system call"
473 kexec is a system call that implements the ability to shutdown your
474 current kernel, and to start another kernel. It is like a reboot
475 but it is independent of the system firmware. And like a reboot
476 you can start any kernel with it, not just Linux.
478 The name comes from the similarity to the exec system call.
480 It is an ongoing process to be certain the hardware in a machine
481 is properly shutdown, so do not be surprised if this code does not
482 initially work for you. It may help to enable device hotplugging
483 support. As of this writing the exact hardware interface is
484 strongly in flux, so no good recommendation can be made.
487 bool "kernel crash dumps (EXPERIMENTAL)"
488 depends on EXPERIMENTAL
490 Generate crash dump after being started by kexec.
491 This should be normally only set in special crash dump kernels
492 which are loaded in the main kernel with kexec-tools into
493 a specially reserved region and then later executed after
494 a crash by kdump/kexec. The crash dump kernel must be compiled
495 to a memory address not used by the main kernel or BIOS using
497 For more details see Documentation/kdump/kdump.txt
499 config PHYSICAL_START
500 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
501 default "0x1000000" if CRASH_DUMP
504 This gives the physical address where the kernel is loaded. Normally
505 for regular kernels this value is 0x200000 (2MB). But in the case
506 of kexec on panic the fail safe kernel needs to run at a different
507 address than the panic-ed kernel. This option is used to set the load
508 address for kernels used to capture crash dump on being kexec'ed
509 after panic. The default value for crash dump kernels is
510 0x1000000 (16MB). This can also be set based on the "X" value as
511 specified in the "crashkernel=YM@XM" command line boot parameter
512 passed to the panic-ed kernel. Typically this parameter is set as
513 crashkernel=64M@16M. Please take a look at
514 Documentation/kdump/kdump.txt for more details about crash dumps.
516 Don't change this unless you know what you are doing.
519 bool "Enable seccomp to safely compute untrusted bytecode"
523 This kernel feature is useful for number crunching applications
524 that may need to compute untrusted bytecode during their
525 execution. By using pipes or other transports made available to
526 the process as file descriptors supporting the read/write
527 syscalls, it's possible to isolate those applications in
528 their own address space using seccomp. Once seccomp is
529 enabled via /proc/<pid>/seccomp, it cannot be disabled
530 and the task is only allowed to execute a few safe syscalls
531 defined by each seccomp mode.
533 If unsure, say Y. Only embedded should say N here.
535 config CC_STACKPROTECTOR
536 bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
537 depends on EXPERIMENTAL
539 This option turns on the -fstack-protector GCC feature. This
540 feature puts, at the beginning of critical functions, a canary
541 value on the stack just before the return address, and validates
542 the value just before actually returning. Stack based buffer
543 overflows (that need to overwrite this return address) now also
544 overwrite the canary, which gets detected and the attack is then
545 neutralized via a kernel panic.
547 This feature requires gcc version 4.2 or above, or a distribution
548 gcc with the feature backported. Older versions are automatically
549 detected and for those versions, this configuration option is ignored.
551 config CC_STACKPROTECTOR_ALL
552 bool "Use stack-protector for all functions"
553 depends on CC_STACKPROTECTOR
555 Normally, GCC only inserts the canary value protection for
556 functions that use large-ish on-stack buffers. By enabling
557 this option, GCC will be asked to do this for ALL functions.
559 source kernel/Kconfig.hz
562 bool "Function reordering"
565 This option enables the toolchain to reorder functions for a more
566 optimal TLB usage. If you have pretty much any version of binutils,
567 this can increase your kernel build time by roughly one minute.
571 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
576 # Use the generic interrupt handling code in kernel/irq/:
578 config GENERIC_HARDIRQS
582 config GENERIC_IRQ_PROBE
586 # we have no ISA slots, but we do have ISA-style DMA.
591 config GENERIC_PENDING_IRQ
593 depends on GENERIC_HARDIRQS && SMP
596 menu "Power management options"
598 source kernel/power/Kconfig
600 source "drivers/acpi/Kconfig"
602 source "arch/x86_64/kernel/cpufreq/Kconfig"
606 menu "Bus options (PCI etc.)"
611 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
618 bool "Support mmconfig PCI config space access"
619 depends on PCI && ACPI
621 source "drivers/pci/pcie/Kconfig"
623 source "drivers/pci/Kconfig"
625 source "drivers/pcmcia/Kconfig"
627 source "drivers/pci/hotplug/Kconfig"
632 menu "Executable file formats / Emulations"
634 source "fs/Kconfig.binfmt"
636 config IA32_EMULATION
637 bool "IA32 Emulation"
639 Include code to run 32-bit programs under a 64-bit kernel. You should likely
640 turn this on, unless you're 100% sure that you don't have any 32-bit programs
644 tristate "IA32 a.out support"
645 depends on IA32_EMULATION
647 Support old a.out binaries in the 32bit emulation.
651 depends on IA32_EMULATION
654 config SYSVIPC_COMPAT
656 depends on COMPAT && SYSVIPC
663 source drivers/Kconfig
665 source "drivers/firmware/Kconfig"
669 menu "Instrumentation Support"
670 depends on EXPERIMENTAL
672 source "arch/x86_64/oprofile/Kconfig"
675 bool "Kprobes (EXPERIMENTAL)"
676 depends on EXPERIMENTAL && MODULES
678 Kprobes allows you to trap at almost any kernel address and
679 execute a callback function. register_kprobe() establishes
680 a probepoint and specifies the callback. Kprobes is useful
681 for kernel debugging, non-intrusive instrumentation and testing.
682 If in doubt, say "N".
685 source "arch/x86_64/Kconfig.debug"
687 source "security/Kconfig"
689 source "crypto/Kconfig"