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"
176 If you say Y here the 'File systems' section, you will be
177 able to update the microcode on Intel processors. You will
178 obviously need the actual microcode binary data itself which is
179 not shipped with the Linux kernel.
181 For latest news and information on obtaining all the required
182 ingredients for this driver, check:
183 <http://www.urbanmyth.org/microcode/>.
185 To compile this driver as a module, choose M here: the
186 module will be called microcode.
187 If you use modprobe or kmod you may also want to add the line
188 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
190 config MICROCODE_OLD_INTERFACE
196 tristate "/dev/cpu/*/msr - Model-specific register support"
198 This device gives privileged processes access to the x86
199 Model-Specific Registers (MSRs). It is a character device with
200 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
201 MSR accesses are directed to a specific CPU on multi-processor
205 tristate "/dev/cpu/*/cpuid - CPU information support"
207 This device gives processes access to the x86 CPUID instruction to
208 be executed on a specific processor. It is a character device
209 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
214 depends on SMP && !MK8
217 config MATH_EMULATION
230 config X86_LOCAL_APIC
235 bool "MTRR (Memory Type Range Register) support"
237 On Intel P6 family processors (Pentium Pro, Pentium II and later)
238 the Memory Type Range Registers (MTRRs) may be used to control
239 processor access to memory ranges. This is most useful if you have
240 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
241 allows bus write transfers to be combined into a larger transfer
242 before bursting over the PCI/AGP bus. This can increase performance
243 of image write operations 2.5 times or more. Saying Y here creates a
244 /proc/mtrr file which may be used to manipulate your processor's
245 MTRRs. Typically the X server should use this.
247 This code has a reasonably generic interface so that similar
248 control registers on other processors can be easily supported
251 Saying Y here also fixes a problem with buggy SMP BIOSes which only
252 set the MTRRs for the boot CPU and not for the secondary CPUs. This
253 can lead to all sorts of problems, so it's good to say Y here.
255 Just say Y here, all x86-64 machines support MTRRs.
257 See <file:Documentation/mtrr.txt> for more information.
260 bool "Symmetric multi-processing support"
262 This enables support for systems with more than one CPU. If you have
263 a system with only one CPU, like most personal computers, say N. If
264 you have a system with more than one CPU, say Y.
266 If you say N here, the kernel will run on single and multiprocessor
267 machines, but will use only one CPU of a multiprocessor machine. If
268 you say Y here, the kernel will run on many, but not all,
269 singleprocessor machines. On a singleprocessor machine, the kernel
270 will run faster if you say N here.
272 If you don't know what to do here, say N.
275 bool "SMT (Hyperthreading) scheduler support"
279 SMT scheduler support improves the CPU scheduler's decision making
280 when dealing with Intel Pentium 4 chips with HyperThreading at a
281 cost of slightly increased overhead in some places. If unsure say
285 bool "Multi-core scheduler support"
289 Multi-core scheduler support improves the CPU scheduler's decision
290 making when dealing with multi-core CPU chips at a cost of slightly
291 increased overhead in some places. If unsure say N here.
293 source "kernel/Kconfig.preempt"
296 bool "Non Uniform Memory Access (NUMA) Support"
299 Enable NUMA (Non Uniform Memory Access) support. The kernel
300 will try to allocate memory used by a CPU on the local memory
301 controller of the CPU and add some more NUMA awareness to the kernel.
302 This code is recommended on all multiprocessor Opteron systems.
303 If the system is EM64T, you should say N unless your system is EM64T
307 bool "Old style AMD Opteron NUMA detection"
308 depends on NUMA && PCI
311 Enable K8 NUMA node topology detection. You should say Y here if
312 you have a multi processor AMD K8 system. This uses an old
313 method to read the NUMA configuration directly from the builtin
314 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
315 instead, which also takes priority if both are compiled in.
320 depends on NEED_MULTIPLE_NODES
322 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
324 config X86_64_ACPI_NUMA
325 bool "ACPI NUMA detection"
332 Enable ACPI SRAT based node topology detection.
335 bool "NUMA emulation"
338 Enable NUMA emulation. A flat machine will be split
339 into virtual nodes when booted with "numa=fake=N", where N is the
340 number of nodes. This is only useful for debugging.
342 config ARCH_DISCONTIGMEM_ENABLE
348 config ARCH_DISCONTIGMEM_ENABLE
352 config ARCH_DISCONTIGMEM_DEFAULT
356 config ARCH_SPARSEMEM_ENABLE
358 depends on (NUMA || EXPERIMENTAL)
360 config ARCH_MEMORY_PROBE
362 depends on MEMORY_HOTPLUG
364 config ARCH_FLATMEM_ENABLE
370 config MEMORY_HOTPLUG_RESERVE
372 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
374 config HAVE_ARCH_EARLY_PFN_TO_NID
378 config OUT_OF_LINE_PFN_TO_PAGE
380 depends on DISCONTIGMEM
383 int "Maximum number of CPUs (2-256)"
388 This allows you to specify the maximum number of CPUs which this
389 kernel will support. Current maximum is 256 CPUs due to
390 APIC addressing limits. Less depending on the hardware.
392 This is purely to save memory - each supported CPU requires
393 memory in the static kernel configuration.
396 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
397 depends on SMP && HOTPLUG && EXPERIMENTAL
399 Say Y here to experiment with turning CPUs off and on. CPUs
400 can be controlled through /sys/devices/system/cpu/cpu#.
401 Say N if you want to disable CPU hotplug.
403 config ARCH_ENABLE_MEMORY_HOTPLUG
410 Use the IA-PC HPET (High Precision Event Timer) to manage
411 time in preference to the PIT and RTC, if a HPET is
412 present. The HPET provides a stable time base on SMP
413 systems, unlike the TSC, but it is more expensive to access,
414 as it is off-chip. You can find the HPET spec at
415 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
417 config HPET_EMULATE_RTC
418 bool "Provide RTC interrupt"
419 depends on HPET_TIMER && RTC=y
421 # Mark as embedded because too many people got it wrong.
422 # The code disables itself when not needed.
424 bool "IOMMU support" if EMBEDDED
430 Support for full DMA access of devices with 32bit memory access only
431 on systems with more than 3GB. This is usually needed for USB,
432 sound, many IDE/SATA chipsets and some other devices.
433 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
434 based IOMMU and a software bounce buffer based IOMMU used on Intel
435 systems and as fallback.
436 The code is only active when needed (enough memory and limited
437 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
441 bool "IBM Calgary IOMMU support"
443 depends on PCI && EXPERIMENTAL
445 Support for hardware IOMMUs in IBM's xSeries x366 and x460
446 systems. Needed to run systems with more than 3GB of memory
447 properly with 32-bit PCI devices that do not support DAC
448 (Double Address Cycle). Calgary also supports bus level
449 isolation, where all DMAs pass through the IOMMU. This
450 prevents them from going anywhere except their intended
451 destination. This catches hard-to-find kernel bugs and
452 mis-behaving drivers and devices that do not use the DMA-API
453 properly to set up their DMA buffers. The IOMMU can be
454 turned off at boot time with the iommu=off parameter.
455 Normally the kernel will make the right choice by itself.
458 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
459 bool "Should Calgary be enabled by default?"
461 depends on CALGARY_IOMMU
463 Should Calgary be enabled by default? if you choose 'y', Calgary
464 will be used (if it exists). If you choose 'n', Calgary will not be
465 used even if it exists. If you choose 'n' and would like to use
466 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
469 # need this always selected by IOMMU for the VIA workaround
474 bool "Machine check support" if EMBEDDED
477 Include a machine check error handler to report hardware errors.
478 This version will require the mcelog utility to decode some
479 machine check error logs. See
480 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
483 bool "Intel MCE features"
484 depends on X86_MCE && X86_LOCAL_APIC
487 Additional support for intel specific MCE features such as
491 bool "AMD MCE features"
492 depends on X86_MCE && X86_LOCAL_APIC
495 Additional support for AMD specific MCE features such as
496 the DRAM Error Threshold.
499 bool "kexec system call"
501 kexec is a system call that implements the ability to shutdown your
502 current kernel, and to start another kernel. It is like a reboot
503 but it is independent of the system firmware. And like a reboot
504 you can start any kernel with it, not just Linux.
506 The name comes from the similarity to the exec system call.
508 It is an ongoing process to be certain the hardware in a machine
509 is properly shutdown, so do not be surprised if this code does not
510 initially work for you. It may help to enable device hotplugging
511 support. As of this writing the exact hardware interface is
512 strongly in flux, so no good recommendation can be made.
515 bool "kernel crash dumps (EXPERIMENTAL)"
516 depends on EXPERIMENTAL
518 Generate crash dump after being started by kexec.
519 This should be normally only set in special crash dump kernels
520 which are loaded in the main kernel with kexec-tools into
521 a specially reserved region and then later executed after
522 a crash by kdump/kexec. The crash dump kernel must be compiled
523 to a memory address not used by the main kernel or BIOS using
525 For more details see Documentation/kdump/kdump.txt
527 config PHYSICAL_START
528 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
529 default "0x1000000" if CRASH_DUMP
532 This gives the physical address where the kernel is loaded. Normally
533 for regular kernels this value is 0x200000 (2MB). But in the case
534 of kexec on panic the fail safe kernel needs to run at a different
535 address than the panic-ed kernel. This option is used to set the load
536 address for kernels used to capture crash dump on being kexec'ed
537 after panic. The default value for crash dump kernels is
538 0x1000000 (16MB). This can also be set based on the "X" value as
539 specified in the "crashkernel=YM@XM" command line boot parameter
540 passed to the panic-ed kernel. Typically this parameter is set as
541 crashkernel=64M@16M. Please take a look at
542 Documentation/kdump/kdump.txt for more details about crash dumps.
544 Don't change this unless you know what you are doing.
547 bool "Enable seccomp to safely compute untrusted bytecode"
551 This kernel feature is useful for number crunching applications
552 that may need to compute untrusted bytecode during their
553 execution. By using pipes or other transports made available to
554 the process as file descriptors supporting the read/write
555 syscalls, it's possible to isolate those applications in
556 their own address space using seccomp. Once seccomp is
557 enabled via /proc/<pid>/seccomp, it cannot be disabled
558 and the task is only allowed to execute a few safe syscalls
559 defined by each seccomp mode.
561 If unsure, say Y. Only embedded should say N here.
563 config CC_STACKPROTECTOR
564 bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
565 depends on EXPERIMENTAL
567 This option turns on the -fstack-protector GCC feature. This
568 feature puts, at the beginning of critical functions, a canary
569 value on the stack just before the return address, and validates
570 the value just before actually returning. Stack based buffer
571 overflows (that need to overwrite this return address) now also
572 overwrite the canary, which gets detected and the attack is then
573 neutralized via a kernel panic.
575 This feature requires gcc version 4.2 or above, or a distribution
576 gcc with the feature backported. Older versions are automatically
577 detected and for those versions, this configuration option is ignored.
579 config CC_STACKPROTECTOR_ALL
580 bool "Use stack-protector for all functions"
581 depends on CC_STACKPROTECTOR
583 Normally, GCC only inserts the canary value protection for
584 functions that use large-ish on-stack buffers. By enabling
585 this option, GCC will be asked to do this for ALL functions.
587 source kernel/Kconfig.hz
590 bool "Function reordering"
593 This option enables the toolchain to reorder functions for a more
594 optimal TLB usage. If you have pretty much any version of binutils,
595 this can increase your kernel build time by roughly one minute.
599 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
604 # Use the generic interrupt handling code in kernel/irq/:
606 config GENERIC_HARDIRQS
610 config GENERIC_IRQ_PROBE
614 # we have no ISA slots, but we do have ISA-style DMA.
619 config GENERIC_PENDING_IRQ
621 depends on GENERIC_HARDIRQS && SMP
624 menu "Power management options"
626 source kernel/power/Kconfig
628 source "drivers/acpi/Kconfig"
630 source "arch/x86_64/kernel/cpufreq/Kconfig"
634 menu "Bus options (PCI etc.)"
639 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
646 bool "Support mmconfig PCI config space access"
647 depends on PCI && ACPI
649 source "drivers/pci/pcie/Kconfig"
651 source "drivers/pci/Kconfig"
653 source "drivers/pcmcia/Kconfig"
655 source "drivers/pci/hotplug/Kconfig"
660 menu "Executable file formats / Emulations"
662 source "fs/Kconfig.binfmt"
664 config IA32_EMULATION
665 bool "IA32 Emulation"
667 Include code to run 32-bit programs under a 64-bit kernel. You should likely
668 turn this on, unless you're 100% sure that you don't have any 32-bit programs
672 tristate "IA32 a.out support"
673 depends on IA32_EMULATION
675 Support old a.out binaries in the 32bit emulation.
679 depends on IA32_EMULATION
682 config SYSVIPC_COMPAT
684 depends on COMPAT && SYSVIPC
691 source drivers/Kconfig
693 source "drivers/firmware/Kconfig"
697 menu "Instrumentation Support"
698 depends on EXPERIMENTAL
700 source "arch/x86_64/oprofile/Kconfig"
703 bool "Kprobes (EXPERIMENTAL)"
704 depends on KALLSYMS && EXPERIMENTAL && MODULES
706 Kprobes allows you to trap at almost any kernel address and
707 execute a callback function. register_kprobe() establishes
708 a probepoint and specifies the callback. Kprobes is useful
709 for kernel debugging, non-intrusive instrumentation and testing.
710 If in doubt, say "N".
713 source "arch/x86_64/Kconfig.debug"
715 source "security/Kconfig"
717 source "crypto/Kconfig"