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 # need this always selected by IOMMU for the VIA workaround
463 bool "Machine check support" if EMBEDDED
466 Include a machine check error handler to report hardware errors.
467 This version will require the mcelog utility to decode some
468 machine check error logs. See
469 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
472 bool "Intel MCE features"
473 depends on X86_MCE && X86_LOCAL_APIC
476 Additional support for intel specific MCE features such as
480 bool "AMD MCE features"
481 depends on X86_MCE && X86_LOCAL_APIC
484 Additional support for AMD specific MCE features such as
485 the DRAM Error Threshold.
488 bool "kexec system call"
490 kexec is a system call that implements the ability to shutdown your
491 current kernel, and to start another kernel. It is like a reboot
492 but it is independent of the system firmware. And like a reboot
493 you can start any kernel with it, not just Linux.
495 The name comes from the similarity to the exec system call.
497 It is an ongoing process to be certain the hardware in a machine
498 is properly shutdown, so do not be surprised if this code does not
499 initially work for you. It may help to enable device hotplugging
500 support. As of this writing the exact hardware interface is
501 strongly in flux, so no good recommendation can be made.
504 bool "kernel crash dumps (EXPERIMENTAL)"
505 depends on EXPERIMENTAL
507 Generate crash dump after being started by kexec.
508 This should be normally only set in special crash dump kernels
509 which are loaded in the main kernel with kexec-tools into
510 a specially reserved region and then later executed after
511 a crash by kdump/kexec. The crash dump kernel must be compiled
512 to a memory address not used by the main kernel or BIOS using
514 For more details see Documentation/kdump/kdump.txt
516 config PHYSICAL_START
517 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
518 default "0x1000000" if CRASH_DUMP
521 This gives the physical address where the kernel is loaded. Normally
522 for regular kernels this value is 0x200000 (2MB). But in the case
523 of kexec on panic the fail safe kernel needs to run at a different
524 address than the panic-ed kernel. This option is used to set the load
525 address for kernels used to capture crash dump on being kexec'ed
526 after panic. The default value for crash dump kernels is
527 0x1000000 (16MB). This can also be set based on the "X" value as
528 specified in the "crashkernel=YM@XM" command line boot parameter
529 passed to the panic-ed kernel. Typically this parameter is set as
530 crashkernel=64M@16M. Please take a look at
531 Documentation/kdump/kdump.txt for more details about crash dumps.
533 Don't change this unless you know what you are doing.
536 bool "Enable seccomp to safely compute untrusted bytecode"
540 This kernel feature is useful for number crunching applications
541 that may need to compute untrusted bytecode during their
542 execution. By using pipes or other transports made available to
543 the process as file descriptors supporting the read/write
544 syscalls, it's possible to isolate those applications in
545 their own address space using seccomp. Once seccomp is
546 enabled via /proc/<pid>/seccomp, it cannot be disabled
547 and the task is only allowed to execute a few safe syscalls
548 defined by each seccomp mode.
550 If unsure, say Y. Only embedded should say N here.
552 config CC_STACKPROTECTOR
553 bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
554 depends on EXPERIMENTAL
556 This option turns on the -fstack-protector GCC feature. This
557 feature puts, at the beginning of critical functions, a canary
558 value on the stack just before the return address, and validates
559 the value just before actually returning. Stack based buffer
560 overflows (that need to overwrite this return address) now also
561 overwrite the canary, which gets detected and the attack is then
562 neutralized via a kernel panic.
564 This feature requires gcc version 4.2 or above, or a distribution
565 gcc with the feature backported. Older versions are automatically
566 detected and for those versions, this configuration option is ignored.
568 config CC_STACKPROTECTOR_ALL
569 bool "Use stack-protector for all functions"
570 depends on CC_STACKPROTECTOR
572 Normally, GCC only inserts the canary value protection for
573 functions that use large-ish on-stack buffers. By enabling
574 this option, GCC will be asked to do this for ALL functions.
576 source kernel/Kconfig.hz
579 bool "Function reordering"
582 This option enables the toolchain to reorder functions for a more
583 optimal TLB usage. If you have pretty much any version of binutils,
584 this can increase your kernel build time by roughly one minute.
588 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
593 # Use the generic interrupt handling code in kernel/irq/:
595 config GENERIC_HARDIRQS
599 config GENERIC_IRQ_PROBE
603 # we have no ISA slots, but we do have ISA-style DMA.
608 config GENERIC_PENDING_IRQ
610 depends on GENERIC_HARDIRQS && SMP
613 menu "Power management options"
615 source kernel/power/Kconfig
617 source "drivers/acpi/Kconfig"
619 source "arch/x86_64/kernel/cpufreq/Kconfig"
623 menu "Bus options (PCI etc.)"
628 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
635 bool "Support mmconfig PCI config space access"
636 depends on PCI && ACPI
638 source "drivers/pci/pcie/Kconfig"
640 source "drivers/pci/Kconfig"
642 source "drivers/pcmcia/Kconfig"
644 source "drivers/pci/hotplug/Kconfig"
649 menu "Executable file formats / Emulations"
651 source "fs/Kconfig.binfmt"
653 config IA32_EMULATION
654 bool "IA32 Emulation"
656 Include code to run 32-bit programs under a 64-bit kernel. You should likely
657 turn this on, unless you're 100% sure that you don't have any 32-bit programs
661 tristate "IA32 a.out support"
662 depends on IA32_EMULATION
664 Support old a.out binaries in the 32bit emulation.
668 depends on IA32_EMULATION
671 config SYSVIPC_COMPAT
673 depends on COMPAT && SYSVIPC
680 source drivers/Kconfig
682 source "drivers/firmware/Kconfig"
686 menu "Instrumentation Support"
687 depends on EXPERIMENTAL
689 source "arch/x86_64/oprofile/Kconfig"
692 bool "Kprobes (EXPERIMENTAL)"
693 depends on KALLSYMS && EXPERIMENTAL && MODULES
695 Kprobes allows you to trap at almost any kernel address and
696 execute a callback function. register_kprobe() establishes
697 a probepoint and specifies the callback. Kprobes is useful
698 for kernel debugging, non-intrusive instrumentation and testing.
699 If in doubt, say "N".
702 source "arch/x86_64/Kconfig.debug"
704 source "security/Kconfig"
706 source "crypto/Kconfig"