# # 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. # someone write a better help text please. 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 in the future do more optimizations. This may improve performance or it may not. Code is still experimental. Say N if unsure. 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 "security/Kconfig" source "crypto/Kconfig" source "lib/Kconfig"