#
# For a description of the syntax of this configuration file,
# see Documentation/kbuild/kconfig-language.txt.
#
# Note: ISA is disabled and will hopefully never be enabled.
# If you managed to buy an ISA x86-64 box you'll have to fix all the
# ISA drivers you need yourself.
#
mainmenu "Linux Kernel Configuration"
config X86_64
bool
default y
help
Port to the x86-64 architecture. x86-64 is a 64-bit extension to the
classical 32-bit x86 architecture. For details see
.
config 64BIT
def_bool y
config X86
bool
default y
config MMU
bool
default y
config ISA
bool
config SBUS
bool
config RWSEM_GENERIC_SPINLOCK
bool
default y
config RWSEM_XCHGADD_ALGORITHM
bool
config X86_CMPXCHG
bool
default y
config EARLY_PRINTK
bool
default y
help
Write kernel log output directly into the VGA buffer or to a serial
port.
This is useful for kernel debugging when your machine crashes very
early before the console code is initialized. For normal operation
it is not recommended because it looks ugly and doesn't cooperate
with klogd/syslogd or the X server. You should normally N here,
unless you want to debug such a crash.
config HPET_TIMER
bool
default y
help
Use the IA-PC HPET (High Precision Event Timer) to manage
time in preference to the PIT and RTC, if a HPET is
present. The HPET provides a stable time base on SMP
systems, unlike the RTC, but it is more expensive to access,
as it is off-chip. You can find the HPET spec at
.
If unsure, say Y.
config HPET_EMULATE_RTC
def_bool HPET_TIMER && RTC=y
config GENERIC_ISA_DMA
bool
default y
source "init/Kconfig"
menu "Processor type and features"
choice
prompt "Processor family"
default MK8
config MK8
bool "AMD-Opteron/Athlon64"
help
Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
config MPSC
bool "Intel x86-64"
help
Optimize for Intel IA32 with 64bit extension CPUs
(Prescott/Nocona/Potomac)
config GENERIC_CPU
bool "Generic-x86-64"
help
Generic x86-64 CPU.
endchoice
#
# Define implied options from the CPU selection here
#
config X86_L1_CACHE_BYTES
int
default "128" if GENERIC_CPU || MPSC
default "64" if MK8
config X86_L1_CACHE_SHIFT
int
default "7" if GENERIC_CPU || MPSC
default "6" if MK8
config X86_TSC
bool
default y
config X86_GOOD_APIC
bool
default y
config MICROCODE
tristate "/dev/cpu/microcode - Intel CPU microcode support"
---help---
If you say Y here the 'File systems' section, you will be
able to update the microcode on Intel processors. You will
obviously need the actual microcode binary data itself which is
not shipped with the Linux kernel.
For latest news and information on obtaining all the required
ingredients for this driver, check:
.
To compile this driver as a module, choose M here: the
module will be called microcode.
If you use modprobe or kmod you may also want to add the line
'alias char-major-10-184 microcode' to your /etc/modules.conf file.
config X86_MSR
tristate "/dev/cpu/*/msr - Model-specific register support"
help
This device gives privileged processes access to the x86
Model-Specific Registers (MSRs). It is a character device with
major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
MSR accesses are directed to a specific CPU on multi-processor
systems.
config X86_CPUID
tristate "/dev/cpu/*/cpuid - CPU information support"
help
This device gives processes access to the x86 CPUID instruction to
be executed on a specific processor. It is a character device
with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
/dev/cpu/31/cpuid.
# disable it for opteron optimized builds because it pulls in ACPI_BOOT
config X86_HT
bool
depends on SMP && !MK8
default y
config MATH_EMULATION
bool
config MCA
bool
config EISA
bool
config X86_IO_APIC
bool
default y
config X86_LOCAL_APIC
bool
default y
config MTRR
bool "MTRR (Memory Type Range Register) support"
---help---
On Intel P6 family processors (Pentium Pro, Pentium II and later)
the Memory Type Range Registers (MTRRs) may be used to control
processor access to memory ranges. This is most useful if you have
a video (VGA) card on a PCI or AGP bus. Enabling write-combining
allows bus write transfers to be combined into a larger transfer
before bursting over the PCI/AGP bus. This can increase performance
of image write operations 2.5 times or more. Saying Y here creates a
/proc/mtrr file which may be used to manipulate your processor's
MTRRs. Typically the X server should use this.
This code has a reasonably generic interface so that similar
control registers on other processors can be easily supported
as well.
Saying Y here also fixes a problem with buggy SMP BIOSes which only
set the MTRRs for the boot CPU and not for the secondary CPUs. This
can lead to all sorts of problems, so it's good to say Y here.
Just say Y here, all x86-64 machines support MTRRs.
See for more information.
config SMP
bool "Symmetric multi-processing support"
---help---
This enables support for systems with more than one CPU. If you have
a system with only one CPU, like most personal computers, say N. If
you have a system with more than one CPU, say Y.
If you say N here, the kernel will run on single and multiprocessor
machines, but will use only one CPU of a multiprocessor machine. If
you say Y here, the kernel will run on many, but not all,
singleprocessor machines. On a singleprocessor machine, the kernel
will run faster if you say N here.
If you don't know what to do here, say N.
config PREEMPT
bool "Preemptible Kernel"
---help---
This option reduces the latency of the kernel when reacting to
real-time or interactive events by allowing a low priority process to
be preempted even if it is in kernel mode executing a system call.
This allows applications to run more reliably even when the system is
under load. On contrary it may also break your drivers and add
priority inheritance problems to your system. Don't select it if
you rely on a stable system or have slightly obscure hardware.
It's also not very well tested on x86-64 currently.
You have been warned.
Say Y here if you are feeling brave and building a kernel for a
desktop, embedded or real-time system. Say N if you are unsure.
config SCHED_SMT
bool "SMT (Hyperthreading) scheduler support"
depends on SMP
default off
help
SMT scheduler support improves the CPU scheduler's decision making
when dealing with Intel Pentium 4 chips with HyperThreading at a
cost of slightly increased overhead in some places. If unsure say
N here.
config K8_NUMA
bool "K8 NUMA support"
depends on SMP
help
Enable NUMA (Non Unified Memory Architecture) support for
AMD Opteron Multiprocessor systems. The kernel will try to allocate
memory used by a CPU on the local memory controller of the CPU
and add some more NUMA awareness to the kernel.
This code is recommended on all multiprocessor Opteron systems
and normally doesn't hurt on others.
config DISCONTIGMEM
bool
depends on K8_NUMA
default y
config NUMA
bool
depends on K8_NUMA
default y
config HAVE_DEC_LOCK
bool
depends on SMP
default y
# actually 64 maximum, but you need to fix the APIC code first
# to use clustered mode or whatever your big iron needs
config NR_CPUS
int "Maximum number of CPUs (2-8)"
range 2 8
depends on SMP
default "8"
help
This allows you to specify the maximum number of CPUs which this
kernel will support. The maximum supported value is 32 and the
minimum value which makes sense is 2.
This is purely to save memory - each supported CPU requires
memory in the static kernel configuration.
config GART_IOMMU
bool "IOMMU support"
help
Support the K8 IOMMU. Needed to run systems with more than 4GB of memory
properly with 32-bit PCI devices that do not support DAC (Double Address
Cycle). The IOMMU can be turned off at runtime with the iommu=off parameter.
Normally the kernel will take the right choice by itself.
If unsure say Y
# need this always enabled with GART_IOMMU for the VIA workaround
config SWIOTLB
bool
depends on GART_IOMMU
default y
config DUMMY_IOMMU
bool
depends on !GART_IOMMU && !SWIOTLB
default y
help
Don't use IOMMU code. This will cause problems when you have more than 4GB
of memory and any 32-bit devices. Don't turn on unless you know what you
are doing.
config X86_MCE
bool
default y
endmenu
menu "Power management options"
source kernel/power/Kconfig
source "drivers/acpi/Kconfig"
source "arch/x86_64/kernel/cpufreq/Kconfig"
endmenu
menu "Bus options (PCI etc.)"
config PCI
bool "PCI support"
# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
config PCI_DIRECT
bool
depends on PCI
default y
config PCI_MMCONFIG
bool "Support mmconfig PCI config space access"
depends on PCI
select ACPI_BOOT
source "drivers/pci/Kconfig"
source "drivers/pcmcia/Kconfig"
source "drivers/pci/hotplug/Kconfig"
endmenu
menu "Executable file formats / Emulations"
source "fs/Kconfig.binfmt"
config IA32_EMULATION
bool "IA32 Emulation"
help
Include code to run 32-bit programs under a 64-bit kernel. You should likely
turn this on, unless you're 100% sure that you don't have any 32-bit programs
left.
config IA32_AOUT
bool "IA32 a.out support"
depends on IA32_EMULATION
help
Support old a.out binaries in the 32bit emulation.
config COMPAT
bool
depends on IA32_EMULATION
default y
config SYSVIPC_COMPAT
bool
depends on COMPAT && SYSVIPC
default y
config UID16
bool
depends on IA32_EMULATION
default y
endmenu
source drivers/Kconfig
source "drivers/firmware/Kconfig"
source fs/Kconfig
source "arch/x86_64/oprofile/Kconfig"
menu "Kernel hacking"
config DEBUG_KERNEL
bool "Kernel debugging"
help
Say Y here if you are developing drivers or trying to debug and
identify kernel problems.
config DEBUG_SLAB
bool "Debug memory allocations"
depends on DEBUG_KERNEL
help
Say Y here to have the kernel do limited verification on memory
allocation as well as poisoning memory on free to catch use of freed
memory.
config MAGIC_SYSRQ
bool "Magic SysRq key"
help
If you say Y here, you will have some control over the system even
if the system crashes for example during kernel debugging (e.g., you
will be able to flush the buffer cache to disk, reboot the system
immediately or dump some status information). This is accomplished
by pressing various keys while holding SysRq (Alt+PrintScreen). It
also works on a serial console (on PC hardware at least), if you
send a BREAK and then within 5 seconds a command keypress. The
keys are documented in . Don't say Y
unless you really know what this hack does.
config DEBUG_SPINLOCK
bool "Spinlock debugging"
depends on DEBUG_KERNEL
help
Say Y here and build SMP to catch missing spinlock initialization
and certain other kinds of spinlock errors commonly made. This is
best used in conjunction with the NMI watchdog so that spinlock
deadlocks are also debuggable.
# !SMP for now because the context switch early causes GPF in segment reloading
# and the GS base checking does the wrong thing then, causing a hang.
config CHECKING
bool "Additional run-time checks"
depends on DEBUG_KERNEL && !SMP
help
Enables some internal consistency checks for kernel debugging.
You should normally say N.
config INIT_DEBUG
bool "Debug __init statements"
depends on DEBUG_KERNEL
help
Fill __init and __initdata at the end of boot. This helps debugging
illegal uses of __init and __initdata after initialization.
config DEBUG_INFO
bool "Compile the kernel with debug info"
depends on DEBUG_KERNEL
help
If you say Y here the resulting kernel image will include
debugging info resulting in a larger kernel image.
Say Y here only if you plan to use gdb to debug the kernel.
Please note that this option requires new binutils.
If you don't debug the kernel, you can say N.
config FRAME_POINTER
bool "Compile the kernel with frame pointers"
help
Compile the kernel with frame pointers. This may help for some
debugging with external debuggers. Note the standard oops backtracer
doesn't make use of this and the x86-64 kernel doesn't ensure an consistent
frame pointer through inline assembly (semaphores etc.)
Normally you should say N.
config IOMMU_DEBUG
depends on GART_IOMMU && DEBUG_KERNEL
bool "Enable IOMMU debugging"
help
Force the IOMMU to on even when you have less than 4GB of
memory and add debugging code. On overflow always panic. And
allow to enable IOMMU leak tracing. Can be disabled at boot
time with iommu=noforce. This will also enable scatter gather
list merging. Currently not recommended for production
code. When you use it make sure you have a big enough
IOMMU/AGP aperture. Most of the options enabled by this can
be set more finegrained using the iommu= command line
options. See Documentation/x86_64/boot-options.txt for more
details.
config IOMMU_LEAK
bool "IOMMU leak tracing"
depends on DEBUG_KERNEL
depends on IOMMU_DEBUG
help
Add a simple leak tracer to the IOMMU code. This is useful when you
are debugging a buggy device driver that leaks IOMMU mappings.
#config X86_REMOTE_DEBUG
# bool "kgdb debugging stub"
endmenu
source "kernel/vserver/Kconfig"
source "security/Kconfig"
source "crypto/Kconfig"
source "lib/Kconfig"