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/>.
37 config RWSEM_GENERIC_SPINLOCK
41 config RWSEM_XCHGADD_ALGORITHM
44 config GENERIC_CALIBRATE_DELAY
56 config GENERIC_ISA_DMA
67 menu "Processor type and features"
70 prompt "Processor family"
74 bool "AMD-Opteron/Athlon64"
76 Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
81 Optimize for Intel Pentium 4 and Xeon CPUs with Intel
82 Extended Memory 64 Technology(EM64T). For details see
83 <http://www.intel.com/technology/64bitextensions/>.
93 # Define implied options from the CPU selection here
95 config X86_L1_CACHE_BYTES
97 default "128" if GENERIC_CPU || MPSC
100 config X86_L1_CACHE_SHIFT
102 default "7" if GENERIC_CPU || MPSC
114 tristate "/dev/cpu/microcode - Intel CPU microcode support"
116 If you say Y here the 'File systems' section, you will be
117 able to update the microcode on Intel processors. You will
118 obviously need the actual microcode binary data itself which is
119 not shipped with the Linux kernel.
121 For latest news and information on obtaining all the required
122 ingredients for this driver, check:
123 <http://www.urbanmyth.org/microcode/>.
125 To compile this driver as a module, choose M here: the
126 module will be called microcode.
127 If you use modprobe or kmod you may also want to add the line
128 'alias char-major-10-184 microcode' to your /etc/modules.conf file.
131 tristate "/dev/cpu/*/msr - Model-specific register support"
133 This device gives privileged processes access to the x86
134 Model-Specific Registers (MSRs). It is a character device with
135 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
136 MSR accesses are directed to a specific CPU on multi-processor
140 tristate "/dev/cpu/*/cpuid - CPU information support"
142 This device gives processes access to the x86 CPUID instruction to
143 be executed on a specific processor. It is a character device
144 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
147 # disable it for opteron optimized builds because it pulls in ACPI_BOOT
150 depends on SMP && !MK8
153 config MATH_EMULATION
166 config X86_LOCAL_APIC
171 bool "MTRR (Memory Type Range Register) support"
173 On Intel P6 family processors (Pentium Pro, Pentium II and later)
174 the Memory Type Range Registers (MTRRs) may be used to control
175 processor access to memory ranges. This is most useful if you have
176 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
177 allows bus write transfers to be combined into a larger transfer
178 before bursting over the PCI/AGP bus. This can increase performance
179 of image write operations 2.5 times or more. Saying Y here creates a
180 /proc/mtrr file which may be used to manipulate your processor's
181 MTRRs. Typically the X server should use this.
183 This code has a reasonably generic interface so that similar
184 control registers on other processors can be easily supported
187 Saying Y here also fixes a problem with buggy SMP BIOSes which only
188 set the MTRRs for the boot CPU and not for the secondary CPUs. This
189 can lead to all sorts of problems, so it's good to say Y here.
191 Just say Y here, all x86-64 machines support MTRRs.
193 See <file:Documentation/mtrr.txt> for more information.
196 bool "Symmetric multi-processing support"
198 This enables support for systems with more than one CPU. If you have
199 a system with only one CPU, like most personal computers, say N. If
200 you have a system with more than one CPU, say Y.
202 If you say N here, the kernel will run on single and multiprocessor
203 machines, but will use only one CPU of a multiprocessor machine. If
204 you say Y here, the kernel will run on many, but not all,
205 singleprocessor machines. On a singleprocessor machine, the kernel
206 will run faster if you say N here.
208 If you don't know what to do here, say N.
211 bool "Preemptible Kernel"
213 This option reduces the latency of the kernel when reacting to
214 real-time or interactive events by allowing a low priority process to
215 be preempted even if it is in kernel mode executing a system call.
216 This allows applications to run more reliably even when the system is
217 under load. On contrary it may also break your drivers and add
218 priority inheritance problems to your system. Don't select it if
219 you rely on a stable system or have slightly obscure hardware.
220 It's also not very well tested on x86-64 currently.
221 You have been warned.
223 Say Y here if you are feeling brave and building a kernel for a
224 desktop, embedded or real-time system. Say N if you are unsure.
227 bool "Preempt The Big Kernel Lock"
231 This option reduces the latency of the kernel by making the
232 big kernel lock preemptible.
234 Say Y here if you are building a kernel for a desktop system.
235 Say N if you are unsure.
238 bool "SMT (Hyperthreading) scheduler support"
242 SMT scheduler support improves the CPU scheduler's decision making
243 when dealing with Intel Pentium 4 chips with HyperThreading at a
244 cost of slightly increased overhead in some places. If unsure say
248 bool "K8 NUMA support"
252 Enable NUMA (Non Unified Memory Architecture) support for
253 AMD Opteron Multiprocessor systems. The kernel will try to allocate
254 memory used by a CPU on the local memory controller of the CPU
255 and add some more NUMA awareness to the kernel.
256 This code is recommended on all multiprocessor Opteron systems
257 and normally doesn't hurt on others.
260 bool "NUMA emulation support"
264 Enable NUMA emulation. A flat machine will be split
265 into virtual nodes when booted with "numa=fake=N", where N is the
266 number of nodes. This is only useful for debugging.
268 config ARCH_DISCONTIGMEM_ENABLE
285 int "Maximum number of CPUs (2-256)"
290 This allows you to specify the maximum number of CPUs which this
291 kernel will support. Current maximum is 256 CPUs due to
292 APIC addressing limits. Less depending on the hardware.
294 This is purely to save memory - each supported CPU requires
295 memory in the static kernel configuration.
301 Use the IA-PC HPET (High Precision Event Timer) to manage
302 time in preference to the PIT and RTC, if a HPET is
303 present. The HPET provides a stable time base on SMP
304 systems, unlike the TSC, but it is more expensive to access,
305 as it is off-chip. You can find the HPET spec at
306 <http://www.intel.com/labs/platcomp/hpet/hpetspec.htm>.
313 Support the ACPI PM timer for time keeping. This is slow,
314 but is useful on some chipsets without HPET on systems with more
315 than one CPU. On a single processor or single socket multi core
316 system it is normally not required.
317 When the PM timer is active 64bit vsyscalls are disabled
318 and should not be enabled (/proc/sys/kernel/vsyscall64 should
320 The kernel selects the PM timer only as a last resort, so it is
321 useful to enable just in case.
323 config HPET_EMULATE_RTC
324 bool "Provide RTC interrupt"
325 depends on HPET_TIMER && RTC=y
331 Support the K8 IOMMU. Needed to run systems with more than 4GB of memory
332 properly with 32-bit PCI devices that do not support DAC (Double Address
333 Cycle). The IOMMU can be turned off at runtime with the iommu=off parameter.
334 Normally the kernel will take the right choice by itself.
337 # need this always enabled with GART_IOMMU for the VIA workaround
340 depends on GART_IOMMU
345 depends on !GART_IOMMU && !SWIOTLB
348 Don't use IOMMU code. This will cause problems when you have more than 4GB
349 of memory and any 32-bit devices. Don't turn on unless you know what you
353 bool "Machine check support" if EMBEDDED
356 Include a machine check error handler to report hardware errors.
357 This version will require the mcelog utility to decode some
358 machine check error logs. See
359 ftp://ftp.x86-64.org/pub/linux/tools/mcelog
362 bool "Intel MCE features"
363 depends on X86_MCE && X86_LOCAL_APIC
366 Additional support for intel specific MCE features such as
370 bool "Enable seccomp to safely compute untrusted bytecode"
374 This kernel feature is useful for number crunching applications
375 that may need to compute untrusted bytecode during their
376 execution. By using pipes or other transports made available to
377 the process as file descriptors supporting the read/write
378 syscalls, it's possible to isolate those applications in
379 their own address space using seccomp. Once seccomp is
380 enabled via /proc/<pid>/seccomp, it cannot be disabled
381 and the task is only allowed to execute a few safe syscalls
382 defined by each seccomp mode.
384 If unsure, say Y. Only embedded should say N here.
389 # Use the generic interrupt handling code in kernel/irq/:
391 config GENERIC_HARDIRQS
395 config GENERIC_IRQ_PROBE
399 # we have no ISA slots, but we do have ISA-style DMA.
404 menu "Power management options"
406 source kernel/power/Kconfig
408 source "drivers/acpi/Kconfig"
410 source "arch/x86_64/kernel/cpufreq/Kconfig"
414 menu "Bus options (PCI etc.)"
419 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
426 bool "Support mmconfig PCI config space access"
427 depends on PCI && ACPI
431 bool "Unordered IO mapping access"
432 depends on EXPERIMENTAL
434 Use unordered stores to access IO memory mappings in device drivers.
435 Still very experimental. When a driver works on IA64/ppc64/pa-risc it should
436 work with this option, but it makes the drivers behave differently
437 from i386. Requires that the driver writer used memory barriers
440 source "drivers/pci/pcie/Kconfig"
442 source "drivers/pci/Kconfig"
444 source "drivers/pcmcia/Kconfig"
446 source "drivers/pci/hotplug/Kconfig"
451 menu "Executable file formats / Emulations"
453 source "fs/Kconfig.binfmt"
455 config IA32_EMULATION
456 bool "IA32 Emulation"
458 Include code to run 32-bit programs under a 64-bit kernel. You should likely
459 turn this on, unless you're 100% sure that you don't have any 32-bit programs
463 bool "IA32 a.out support"
464 depends on IA32_EMULATION
466 Support old a.out binaries in the 32bit emulation.
470 depends on IA32_EMULATION
473 config SYSVIPC_COMPAT
475 depends on COMPAT && SYSVIPC
480 depends on IA32_EMULATION
485 source drivers/Kconfig
487 source "drivers/firmware/Kconfig"
491 source "arch/x86_64/oprofile/Kconfig"
493 source "arch/x86_64/Kconfig.debug"
495 source "security/Kconfig"
497 source "crypto/Kconfig"