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 GENERIC_TIME_VSYSCALL
35 config GENERIC_CMOS_UPDATE
39 config CLOCKSOURCE_WATCHDOG
43 config GENERIC_CLOCKEVENTS
47 config GENERIC_CLOCKEVENTS_BROADCAST
55 config LOCKDEP_SUPPORT
59 config STACKTRACE_SUPPORT
63 config SEMAPHORE_SLEEPERS
81 config GENERIC_HWEIGHT
85 config GENERIC_ISA_DMA
93 config ARCH_MAY_HAVE_PC_FDC
97 config ARCH_POPULATES_NODE_MAP
114 source "init/Kconfig"
117 menu "Processor type and features"
119 source "kernel/time/Kconfig"
122 prompt "Subarchitecture Type"
128 Choose this option if your computer is a standard PC or compatible.
131 bool "Support for ScaleMP vSMP"
132 depends on X86_64 && PCI
134 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
135 supposed to run on these EM64T-based machines. Only choose this option
136 if you have one of these machines.
140 source "arch/x86/Kconfig.cpu"
143 tristate "/dev/cpu/microcode - Intel CPU microcode support"
146 If you say Y here the 'File systems' section, you will be
147 able to update the microcode on Intel processors. You will
148 obviously need the actual microcode binary data itself which is
149 not shipped with the Linux kernel.
151 For latest news and information on obtaining all the required
152 ingredients for this driver, check:
153 <http://www.urbanmyth.org/microcode/>.
155 To compile this driver as a module, choose M here: the
156 module will be called microcode.
157 If you use modprobe or kmod you may also want to add the line
158 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
160 config MICROCODE_OLD_INTERFACE
166 tristate "/dev/cpu/*/msr - Model-specific register support"
168 This device gives privileged processes access to the x86
169 Model-Specific Registers (MSRs). It is a character device with
170 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
171 MSR accesses are directed to a specific CPU on multi-processor
175 tristate "/dev/cpu/*/cpuid - CPU information support"
177 This device gives processes access to the x86 CPUID instruction to
178 be executed on a specific processor. It is a character device
179 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
184 depends on SMP && !MK8
187 config MATH_EMULATION
200 config X86_LOCAL_APIC
205 bool "MTRR (Memory Type Range Register) support"
207 On Intel P6 family processors (Pentium Pro, Pentium II and later)
208 the Memory Type Range Registers (MTRRs) may be used to control
209 processor access to memory ranges. This is most useful if you have
210 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
211 allows bus write transfers to be combined into a larger transfer
212 before bursting over the PCI/AGP bus. This can increase performance
213 of image write operations 2.5 times or more. Saying Y here creates a
214 /proc/mtrr file which may be used to manipulate your processor's
215 MTRRs. Typically the X server should use this.
217 This code has a reasonably generic interface so that similar
218 control registers on other processors can be easily supported
221 Saying Y here also fixes a problem with buggy SMP BIOSes which only
222 set the MTRRs for the boot CPU and not for the secondary CPUs. This
223 can lead to all sorts of problems, so it's good to say Y here.
225 Just say Y here, all x86-64 machines support MTRRs.
227 See <file:Documentation/mtrr.txt> for more information.
230 bool "Symmetric multi-processing support"
232 This enables support for systems with more than one CPU. If you have
233 a system with only one CPU, like most personal computers, say N. If
234 you have a system with more than one CPU, say Y.
236 If you say N here, the kernel will run on single and multiprocessor
237 machines, but will use only one CPU of a multiprocessor machine. If
238 you say Y here, the kernel will run on many, but not all,
239 singleprocessor machines. On a singleprocessor machine, the kernel
240 will run faster if you say N here.
242 If you don't know what to do here, say N.
245 bool "SMT (Hyperthreading) scheduler support"
249 SMT scheduler support improves the CPU scheduler's decision making
250 when dealing with Intel Pentium 4 chips with HyperThreading at a
251 cost of slightly increased overhead in some places. If unsure say
255 bool "Multi-core scheduler support"
259 Multi-core scheduler support improves the CPU scheduler's decision
260 making when dealing with multi-core CPU chips at a cost of slightly
261 increased overhead in some places. If unsure say N here.
263 source "kernel/Kconfig.preempt"
266 bool "Non Uniform Memory Access (NUMA) Support"
269 Enable NUMA (Non Uniform Memory Access) support. The kernel
270 will try to allocate memory used by a CPU on the local memory
271 controller of the CPU and add some more NUMA awareness to the kernel.
272 This code is recommended on all multiprocessor Opteron systems.
273 If the system is EM64T, you should say N unless your system is EM64T
277 bool "Old style AMD Opteron NUMA detection"
278 depends on X86_64 && NUMA && PCI
281 Enable K8 NUMA node topology detection. You should say Y here if
282 you have a multi processor AMD K8 system. This uses an old
283 method to read the NUMA configuration directly from the builtin
284 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
285 instead, which also takes priority if both are compiled in.
289 default "6" if X86_64
290 depends on NEED_MULTIPLE_NODES
292 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
294 config X86_64_ACPI_NUMA
295 bool "ACPI NUMA detection"
296 depends on X86_64 && NUMA
302 Enable ACPI SRAT based node topology detection.
305 bool "NUMA emulation"
306 depends on X86_64 && NUMA
308 Enable NUMA emulation. A flat machine will be split
309 into virtual nodes when booted with "numa=fake=N", where N is the
310 number of nodes. This is only useful for debugging.
312 config ARCH_DISCONTIGMEM_ENABLE
317 config ARCH_DISCONTIGMEM_DEFAULT
321 config ARCH_SPARSEMEM_ENABLE
323 depends on (NUMA || EXPERIMENTAL)
324 select SPARSEMEM_VMEMMAP_ENABLE
326 config ARCH_MEMORY_PROBE
328 depends on MEMORY_HOTPLUG
330 config ARCH_FLATMEM_ENABLE
336 config MEMORY_HOTPLUG_RESERVE
338 depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
340 config HAVE_ARCH_EARLY_PFN_TO_NID
344 config OUT_OF_LINE_PFN_TO_PAGE
346 depends on DISCONTIGMEM
349 int "Maximum number of CPUs (2-255)"
354 This allows you to specify the maximum number of CPUs which this
355 kernel will support. Current maximum is 255 CPUs due to
356 APIC addressing limits. Less depending on the hardware.
358 This is purely to save memory - each supported CPU requires
359 memory in the static kernel configuration.
361 config PHYSICAL_ALIGN
363 default "0x200000" if X86_64
366 bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
367 depends on SMP && HOTPLUG && EXPERIMENTAL
369 Say Y here to experiment with turning CPUs off and on. CPUs
370 can be controlled through /sys/devices/system/cpu/cpu#.
371 This is also required for suspend/hibernation on SMP systems.
373 Say N if you want to disable CPU hotplug and don't need to
376 config ARCH_ENABLE_MEMORY_HOTPLUG
383 Use the IA-PC HPET (High Precision Event Timer) to manage
384 time in preference to the PIT and RTC, if a HPET is
385 present. The HPET provides a stable time base on SMP
386 systems, unlike the TSC, but it is more expensive to access,
387 as it is off-chip. You can find the HPET spec at
388 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
390 config HPET_EMULATE_RTC
392 depends on HPET_TIMER && RTC=y
395 # Mark as embedded because too many people got it wrong.
396 # The code disables itself when not needed.
398 bool "GART IOMMU support" if EMBEDDED
402 depends on X86_64 && PCI
404 Support for full DMA access of devices with 32bit memory access only
405 on systems with more than 3GB. This is usually needed for USB,
406 sound, many IDE/SATA chipsets and some other devices.
407 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
408 based hardware IOMMU and a software bounce buffer based IOMMU used
409 on Intel systems and as fallback.
410 The code is only active when needed (enough memory and limited
411 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
415 bool "IBM Calgary IOMMU support"
417 depends on X86_64 && PCI && EXPERIMENTAL
419 Support for hardware IOMMUs in IBM's xSeries x366 and x460
420 systems. Needed to run systems with more than 3GB of memory
421 properly with 32-bit PCI devices that do not support DAC
422 (Double Address Cycle). Calgary also supports bus level
423 isolation, where all DMAs pass through the IOMMU. This
424 prevents them from going anywhere except their intended
425 destination. This catches hard-to-find kernel bugs and
426 mis-behaving drivers and devices that do not use the DMA-API
427 properly to set up their DMA buffers. The IOMMU can be
428 turned off at boot time with the iommu=off parameter.
429 Normally the kernel will make the right choice by itself.
432 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
433 bool "Should Calgary be enabled by default?"
435 depends on CALGARY_IOMMU
437 Should Calgary be enabled by default? if you choose 'y', Calgary
438 will be used (if it exists). If you choose 'n', Calgary will not be
439 used even if it exists. If you choose 'n' and would like to use
440 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
443 # need this always selected by IOMMU for the VIA workaround
447 Support for software bounce buffers used on x86-64 systems
448 which don't have a hardware IOMMU (e.g. the current generation
449 of Intel's x86-64 CPUs). Using this PCI devices which can only
450 access 32-bits of memory can be used on systems with more than
451 3 GB of memory. If unsure, say Y.
454 bool "Machine check support" if EMBEDDED
457 Include a machine check error handler to report hardware errors.
458 This version will require the mcelog utility to decode some
459 machine check error logs. See
460 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
463 bool "Intel MCE features"
464 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
467 Additional support for intel specific MCE features such as
471 bool "AMD MCE features"
472 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
475 Additional support for AMD specific MCE features such as
476 the DRAM Error Threshold.
479 bool "kexec system call"
481 kexec is a system call that implements the ability to shutdown your
482 current kernel, and to start another kernel. It is like a reboot
483 but it is independent of the system firmware. And like a reboot
484 you can start any kernel with it, not just Linux.
486 The name comes from the similarity to the exec system call.
488 It is an ongoing process to be certain the hardware in a machine
489 is properly shutdown, so do not be surprised if this code does not
490 initially work for you. It may help to enable device hotplugging
491 support. As of this writing the exact hardware interface is
492 strongly in flux, so no good recommendation can be made.
495 bool "kernel crash dumps (EXPERIMENTAL)"
496 depends on EXPERIMENTAL
498 Generate crash dump after being started by kexec.
499 This should be normally only set in special crash dump kernels
500 which are loaded in the main kernel with kexec-tools into
501 a specially reserved region and then later executed after
502 a crash by kdump/kexec. The crash dump kernel must be compiled
503 to a memory address not used by the main kernel or BIOS using
504 PHYSICAL_START, or it must be built as a relocatable image
505 (CONFIG_RELOCATABLE=y).
506 For more details see Documentation/kdump/kdump.txt
509 bool "Build a relocatable kernel (EXPERIMENTAL)"
510 depends on EXPERIMENTAL
512 Builds a relocatable kernel. This enables loading and running
513 a kernel binary from a different physical address than it has
516 One use is for the kexec on panic case where the recovery kernel
517 must live at a different physical address than the primary
520 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
521 it has been loaded at and the compile time physical address
522 (CONFIG_PHYSICAL_START) is ignored.
524 config PHYSICAL_START
525 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
528 This gives the physical address where the kernel is loaded. It
529 should be aligned to 2MB boundary.
531 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
532 bzImage will decompress itself to above physical address and
533 run from there. Otherwise, bzImage will run from the address where
534 it has been loaded by the boot loader and will ignore above physical
537 In normal kdump cases one does not have to set/change this option
538 as now bzImage can be compiled as a completely relocatable image
539 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
540 address. This option is mainly useful for the folks who don't want
541 to use a bzImage for capturing the crash dump and want to use a
544 So if you are using bzImage for capturing the crash dump, leave
545 the value here unchanged to 0x200000 and set CONFIG_RELOCATABLE=y.
546 Otherwise if you plan to use vmlinux for capturing the crash dump
547 change this value to start of the reserved region (Typically 16MB
548 0x1000000). In other words, it can be set based on the "X" value as
549 specified in the "crashkernel=YM@XM" command line boot parameter
550 passed to the panic-ed kernel. Typically this parameter is set as
551 crashkernel=64M@16M. Please take a look at
552 Documentation/kdump/kdump.txt for more details about crash dumps.
554 Usage of bzImage for capturing the crash dump is advantageous as
555 one does not have to build two kernels. Same kernel can be used
556 as production kernel and capture kernel.
558 Don't change this unless you know what you are doing.
561 bool "Enable seccomp to safely compute untrusted bytecode"
565 This kernel feature is useful for number crunching applications
566 that may need to compute untrusted bytecode during their
567 execution. By using pipes or other transports made available to
568 the process as file descriptors supporting the read/write
569 syscalls, it's possible to isolate those applications in
570 their own address space using seccomp. Once seccomp is
571 enabled via /proc/<pid>/seccomp, it cannot be disabled
572 and the task is only allowed to execute a few safe syscalls
573 defined by each seccomp mode.
575 If unsure, say Y. Only embedded should say N here.
577 config CC_STACKPROTECTOR
578 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
579 depends on X86_64 && EXPERIMENTAL
581 This option turns on the -fstack-protector GCC feature. This
582 feature puts, at the beginning of critical functions, a canary
583 value on the stack just before the return address, and validates
584 the value just before actually returning. Stack based buffer
585 overflows (that need to overwrite this return address) now also
586 overwrite the canary, which gets detected and the attack is then
587 neutralized via a kernel panic.
589 This feature requires gcc version 4.2 or above, or a distribution
590 gcc with the feature backported. Older versions are automatically
591 detected and for those versions, this configuration option is ignored.
593 config CC_STACKPROTECTOR_ALL
594 bool "Use stack-protector for all functions"
595 depends on CC_STACKPROTECTOR
597 Normally, GCC only inserts the canary value protection for
598 functions that use large-ish on-stack buffers. By enabling
599 this option, GCC will be asked to do this for ALL functions.
601 source kernel/Kconfig.hz
605 depends on AGP_AMD64 || GART_IOMMU || (PCI && NUMA)
610 # Use the generic interrupt handling code in kernel/irq/:
612 config GENERIC_HARDIRQS
616 config GENERIC_IRQ_PROBE
620 config GENERIC_PENDING_IRQ
622 depends on GENERIC_HARDIRQS && SMP
625 source "arch/x86/Kconfig"