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.
189 config MICROCODE_OLD_INTERFACE
195 tristate "/dev/cpu/*/msr - Model-specific register support"
197 This device gives privileged processes access to the x86
198 Model-Specific Registers (MSRs). It is a character device with
199 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
200 MSR accesses are directed to a specific CPU on multi-processor
204 tristate "/dev/cpu/*/cpuid - CPU information support"
206 This device gives processes access to the x86 CPUID instruction to
207 be executed on a specific processor. It is a character device
208 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
213 depends on SMP && !MK8
216 config MATH_EMULATION
229 config X86_LOCAL_APIC
234 bool "MTRR (Memory Type Range Register) support"
236 On Intel P6 family processors (Pentium Pro, Pentium II and later)
237 the Memory Type Range Registers (MTRRs) may be used to control
238 processor access to memory ranges. This is most useful if you have
239 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
240 allows bus write transfers to be combined into a larger transfer
241 before bursting over the PCI/AGP bus. This can increase performance
242 of image write operations 2.5 times or more. Saying Y here creates a
243 /proc/mtrr file which may be used to manipulate your processor's
244 MTRRs. Typically the X server should use this.
246 This code has a reasonably generic interface so that similar
247 control registers on other processors can be easily supported
250 Saying Y here also fixes a problem with buggy SMP BIOSes which only
251 set the MTRRs for the boot CPU and not for the secondary CPUs. This
252 can lead to all sorts of problems, so it's good to say Y here.
254 Just say Y here, all x86-64 machines support MTRRs.
256 See <file:Documentation/mtrr.txt> for more information.
259 bool "Symmetric multi-processing support"
261 This enables support for systems with more than one CPU. If you have
262 a system with only one CPU, like most personal computers, say N. If
263 you have a system with more than one CPU, say Y.
265 If you say N here, the kernel will run on single and multiprocessor
266 machines, but will use only one CPU of a multiprocessor machine. If
267 you say Y here, the kernel will run on many, but not all,
268 singleprocessor machines. On a singleprocessor machine, the kernel
269 will run faster if you say N here.
271 If you don't know what to do here, say N.
274 bool "SMT (Hyperthreading) scheduler support"
278 SMT scheduler support improves the CPU scheduler's decision making
279 when dealing with Intel Pentium 4 chips with HyperThreading at a
280 cost of slightly increased overhead in some places. If unsure say
284 bool "Multi-core scheduler support"
288 Multi-core scheduler support improves the CPU scheduler's decision
289 making when dealing with multi-core CPU chips at a cost of slightly
290 increased overhead in some places. If unsure say N here.
292 source "kernel/Kconfig.preempt"
295 bool "Non Uniform Memory Access (NUMA) Support"
298 Enable NUMA (Non Uniform Memory Access) support. The kernel
299 will try to allocate memory used by a CPU on the local memory
300 controller of the CPU and add some more NUMA awareness to the kernel.
301 This code is recommended on all multiprocessor Opteron systems.
302 If the system is EM64T, you should say N unless your system is EM64T
306 bool "Old style AMD Opteron NUMA detection"
307 depends on NUMA && PCI
310 Enable K8 NUMA node topology detection. You should say Y here if
311 you have a multi processor AMD K8 system. This uses an old
312 method to read the NUMA configurtion directly from the builtin
313 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
314 instead, which also takes priority if both are compiled in.
319 depends on NEED_MULTIPLE_NODES
321 # Dummy CONFIG option to select ACPI_NUMA from drivers/acpi/Kconfig.
323 config X86_64_ACPI_NUMA
324 bool "ACPI NUMA detection"
331 Enable ACPI SRAT based node topology detection.
334 bool "NUMA emulation"
337 Enable NUMA emulation. A flat machine will be split
338 into virtual nodes when booted with "numa=fake=N", where N is the
339 number of nodes. This is only useful for debugging.
341 config ARCH_DISCONTIGMEM_ENABLE
347 config ARCH_DISCONTIGMEM_ENABLE
351 config ARCH_DISCONTIGMEM_DEFAULT
355 config ARCH_SPARSEMEM_ENABLE
357 depends on (NUMA || EXPERIMENTAL)
359 config ARCH_MEMORY_PROBE
361 depends on MEMORY_HOTPLUG
363 config ARCH_FLATMEM_ENABLE
369 config HAVE_ARCH_EARLY_PFN_TO_NID
373 config OUT_OF_LINE_PFN_TO_PAGE
375 depends on DISCONTIGMEM
378 int "Maximum number of CPUs (2-256)"
383 This allows you to specify the maximum number of CPUs which this
384 kernel will support. Current maximum is 256 CPUs due to
385 APIC addressing limits. Less depending on the hardware.
387 This is purely to save memory - each supported CPU requires
388 memory in the static kernel configuration.
391 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
392 depends on SMP && HOTPLUG && EXPERIMENTAL
394 Say Y here to experiment with turning CPUs off and on. CPUs
395 can be controlled through /sys/devices/system/cpu/cpu#.
396 Say N if you want to disable CPU hotplug.
398 config ARCH_ENABLE_MEMORY_HOTPLUG
405 Use the IA-PC HPET (High Precision Event Timer) to manage
406 time in preference to the PIT and RTC, if a HPET is
407 present. The HPET provides a stable time base on SMP
408 systems, unlike the TSC, but it is more expensive to access,
409 as it is off-chip. You can find the HPET spec at
410 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
412 config HPET_EMULATE_RTC
413 bool "Provide RTC interrupt"
414 depends on HPET_TIMER && RTC=y
416 # Mark as embedded because too many people got it wrong.
417 # The code disables itself when not needed.
419 bool "IOMMU support" if EMBEDDED
425 Support for full DMA access of devices with 32bit memory access only
426 on systems with more than 3GB. This is usually needed for USB,
427 sound, many IDE/SATA chipsets and some other devices.
428 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
429 based IOMMU and a software bounce buffer based IOMMU used on Intel
430 systems and as fallback.
431 The code is only active when needed (enough memory and limited
432 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
436 bool "IBM Calgary IOMMU support"
438 depends on PCI && EXPERIMENTAL
440 Support for hardware IOMMUs in IBM's xSeries x366 and x460
441 systems. Needed to run systems with more than 3GB of memory
442 properly with 32-bit PCI devices that do not support DAC
443 (Double Address Cycle). Calgary also supports bus level
444 isolation, where all DMAs pass through the IOMMU. This
445 prevents them from going anywhere except their intended
446 destination. This catches hard-to-find kernel bugs and
447 mis-behaving drivers and devices that do not use the DMA-API
448 properly to set up their DMA buffers. The IOMMU can be
449 turned off at boot time with the iommu=off parameter.
450 Normally the kernel will make the right choice by itself.
453 # need this always selected by IOMMU for the VIA workaround
458 bool "Machine check support" if EMBEDDED
461 Include a machine check error handler to report hardware errors.
462 This version will require the mcelog utility to decode some
463 machine check error logs. See
464 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
467 bool "Intel MCE features"
468 depends on X86_MCE && X86_LOCAL_APIC
471 Additional support for intel specific MCE features such as
475 bool "AMD MCE features"
476 depends on X86_MCE && X86_LOCAL_APIC
479 Additional support for AMD specific MCE features such as
480 the DRAM Error Threshold.
483 bool "kexec system call"
485 kexec is a system call that implements the ability to shutdown your
486 current kernel, and to start another kernel. It is like a reboot
487 but it is independent of the system firmware. And like a reboot
488 you can start any kernel with it, not just Linux.
490 The name comes from the similarity to the exec system call.
492 It is an ongoing process to be certain the hardware in a machine
493 is properly shutdown, so do not be surprised if this code does not
494 initially work for you. It may help to enable device hotplugging
495 support. As of this writing the exact hardware interface is
496 strongly in flux, so no good recommendation can be made.
499 bool "kernel crash dumps (EXPERIMENTAL)"
500 depends on EXPERIMENTAL
502 Generate crash dump after being started by kexec.
503 This should be normally only set in special crash dump kernels
504 which are loaded in the main kernel with kexec-tools into
505 a specially reserved region and then later executed after
506 a crash by kdump/kexec. The crash dump kernel must be compiled
507 to a memory address not used by the main kernel or BIOS using
509 For more details see Documentation/kdump/kdump.txt
511 config PHYSICAL_START
512 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
513 default "0x1000000" if CRASH_DUMP
516 This gives the physical address where the kernel is loaded. Normally
517 for regular kernels this value is 0x200000 (2MB). But in the case
518 of kexec on panic the fail safe kernel needs to run at a different
519 address than the panic-ed kernel. This option is used to set the load
520 address for kernels used to capture crash dump on being kexec'ed
521 after panic. The default value for crash dump kernels is
522 0x1000000 (16MB). This can also be set based on the "X" value as
523 specified in the "crashkernel=YM@XM" command line boot parameter
524 passed to the panic-ed kernel. Typically this parameter is set as
525 crashkernel=64M@16M. Please take a look at
526 Documentation/kdump/kdump.txt for more details about crash dumps.
528 Don't change this unless you know what you are doing.
531 bool "Enable seccomp to safely compute untrusted bytecode"
535 This kernel feature is useful for number crunching applications
536 that may need to compute untrusted bytecode during their
537 execution. By using pipes or other transports made available to
538 the process as file descriptors supporting the read/write
539 syscalls, it's possible to isolate those applications in
540 their own address space using seccomp. Once seccomp is
541 enabled via /proc/<pid>/seccomp, it cannot be disabled
542 and the task is only allowed to execute a few safe syscalls
543 defined by each seccomp mode.
545 If unsure, say Y. Only embedded should say N here.
547 config CC_STACKPROTECTOR
548 bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
549 depends on EXPERIMENTAL
551 This option turns on the -fstack-protector GCC feature. This
552 feature puts, at the beginning of critical functions, a canary
553 value on the stack just before the return address, and validates
554 the value just before actually returning. Stack based buffer
555 overflows (that need to overwrite this return address) now also
556 overwrite the canary, which gets detected and the attack is then
557 neutralized via a kernel panic.
559 This feature requires gcc version 4.2 or above, or a distribution
560 gcc with the feature backported. Older versions are automatically
561 detected and for those versions, this configuration option is ignored.
563 config CC_STACKPROTECTOR_ALL
564 bool "Use stack-protector for all functions"
565 depends on CC_STACKPROTECTOR
567 Normally, GCC only inserts the canary value protection for
568 functions that use large-ish on-stack buffers. By enabling
569 this option, GCC will be asked to do this for ALL functions.
571 source kernel/Kconfig.hz
574 bool "Function reordering"
577 This option enables the toolchain to reorder functions for a more
578 optimal TLB usage. If you have pretty much any version of binutils,
579 this can increase your kernel build time by roughly one minute.
583 depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
588 # Use the generic interrupt handling code in kernel/irq/:
590 config GENERIC_HARDIRQS
594 config GENERIC_IRQ_PROBE
598 # we have no ISA slots, but we do have ISA-style DMA.
603 config GENERIC_PENDING_IRQ
605 depends on GENERIC_HARDIRQS && SMP
608 menu "Power management options"
610 source kernel/power/Kconfig
612 source "drivers/acpi/Kconfig"
614 source "arch/x86_64/kernel/cpufreq/Kconfig"
618 menu "Bus options (PCI etc.)"
623 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
630 bool "Support mmconfig PCI config space access"
631 depends on PCI && ACPI
633 source "drivers/pci/pcie/Kconfig"
635 source "drivers/pci/Kconfig"
637 source "drivers/pcmcia/Kconfig"
639 source "drivers/pci/hotplug/Kconfig"
644 menu "Executable file formats / Emulations"
646 source "fs/Kconfig.binfmt"
648 config IA32_EMULATION
649 bool "IA32 Emulation"
651 Include code to run 32-bit programs under a 64-bit kernel. You should likely
652 turn this on, unless you're 100% sure that you don't have any 32-bit programs
656 tristate "IA32 a.out support"
657 depends on IA32_EMULATION
659 Support old a.out binaries in the 32bit emulation.
663 depends on IA32_EMULATION
666 config SYSVIPC_COMPAT
668 depends on COMPAT && SYSVIPC
675 source drivers/Kconfig
677 source "drivers/firmware/Kconfig"
681 menu "Instrumentation Support"
682 depends on EXPERIMENTAL
684 source "arch/x86_64/oprofile/Kconfig"
687 bool "Kprobes (EXPERIMENTAL)"
688 depends on EXPERIMENTAL && MODULES
690 Kprobes allows you to trap at almost any kernel address and
691 execute a callback function. register_kprobe() establishes
692 a probepoint and specifies the callback. Kprobes is useful
693 for kernel debugging, non-intrusive instrumentation and testing.
694 If in doubt, say "N".
697 source "arch/x86_64/Kconfig.debug"
699 source "security/Kconfig"
701 source "crypto/Kconfig"