# Select 32 or 64 bit config 64BIT bool "64-bit kernel" if ARCH = "x86" default ARCH = "x86_64" ---help--- Say yes to build a 64-bit kernel - formerly known as x86_64 Say no to build a 32-bit kernel - formerly known as i386 config X86_32 def_bool !64BIT select CLKSRC_I8253 config X86_64 def_bool 64BIT ### Arch settings config X86 def_bool y select HAVE_AOUT if X86_32 select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_IDE select HAVE_OPROFILE select HAVE_PERF_EVENTS select HAVE_IRQ_WORK select HAVE_IOREMAP_PROT select HAVE_KPROBES select HAVE_MEMBLOCK select ARCH_WANT_OPTIONAL_GPIOLIB select ARCH_WANT_FRAME_POINTERS select HAVE_DMA_ATTRS select HAVE_KRETPROBES select HAVE_OPTPROBES select HAVE_FTRACE_MCOUNT_RECORD select HAVE_C_RECORDMCOUNT select HAVE_DYNAMIC_FTRACE select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_GRAPH_FP_TEST select HAVE_FUNCTION_TRACE_MCOUNT_TEST select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE select HAVE_SYSCALL_TRACEPOINTS select HAVE_KVM select HAVE_ARCH_KGDB select HAVE_ARCH_TRACEHOOK select HAVE_GENERIC_DMA_COHERENT if X86_32 select HAVE_EFFICIENT_UNALIGNED_ACCESS select USER_STACKTRACE_SUPPORT select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_DMA_API_DEBUG select HAVE_KERNEL_GZIP select HAVE_KERNEL_BZIP2 select HAVE_KERNEL_LZMA select HAVE_KERNEL_XZ select HAVE_KERNEL_LZO select HAVE_HW_BREAKPOINT select HAVE_MIXED_BREAKPOINTS_REGS select PERF_EVENTS select HAVE_PERF_EVENTS_NMI select ANON_INODES select HAVE_ARCH_KMEMCHECK select HAVE_USER_RETURN_NOTIFIER select HAVE_ARCH_JUMP_LABEL select HAVE_TEXT_POKE_SMP select HAVE_GENERIC_HARDIRQS select HAVE_SPARSE_IRQ select GENERIC_FIND_FIRST_BIT select GENERIC_IRQ_PROBE select GENERIC_PENDING_IRQ if SMP select GENERIC_IRQ_SHOW select IRQ_FORCED_THREADING select USE_GENERIC_SMP_HELPERS if SMP select HAVE_BPF_JIT if (X86_64 && NET) select I8253_LOCK config INSTRUCTION_DECODER def_bool (KPROBES || PERF_EVENTS) config OUTPUT_FORMAT string default "elf32-i386" if X86_32 default "elf64-x86-64" if X86_64 config ARCH_DEFCONFIG string default "arch/x86/configs/i386_defconfig" if X86_32 default "arch/x86/configs/x86_64_defconfig" if X86_64 config GENERIC_CMOS_UPDATE def_bool y config CLOCKSOURCE_WATCHDOG def_bool y config GENERIC_CLOCKEVENTS def_bool y config GENERIC_CLOCKEVENTS_BROADCAST def_bool y depends on X86_64 || (X86_32 && X86_LOCAL_APIC) config LOCKDEP_SUPPORT def_bool y config STACKTRACE_SUPPORT def_bool y config HAVE_LATENCYTOP_SUPPORT def_bool y config MMU def_bool y config ZONE_DMA bool "DMA memory allocation support" if EXPERT default y help DMA memory allocation support allows devices with less than 32-bit addressing to allocate within the first 16MB of address space. Disable if no such devices will be used. If unsure, say Y. config SBUS bool config NEED_DMA_MAP_STATE def_bool (X86_64 || DMAR || DMA_API_DEBUG) config NEED_SG_DMA_LENGTH def_bool y config GENERIC_ISA_DMA def_bool ISA_DMA_API config GENERIC_IOMAP def_bool y config GENERIC_BUG def_bool y depends on BUG select GENERIC_BUG_RELATIVE_POINTERS if X86_64 config GENERIC_BUG_RELATIVE_POINTERS bool config GENERIC_HWEIGHT def_bool y config GENERIC_GPIO bool config ARCH_MAY_HAVE_PC_FDC def_bool ISA_DMA_API config RWSEM_GENERIC_SPINLOCK def_bool !X86_XADD config RWSEM_XCHGADD_ALGORITHM def_bool X86_XADD config ARCH_HAS_CPU_IDLE_WAIT def_bool y config GENERIC_CALIBRATE_DELAY def_bool y config GENERIC_TIME_VSYSCALL bool default X86_64 config ARCH_HAS_CPU_RELAX def_bool y config ARCH_HAS_DEFAULT_IDLE def_bool y config ARCH_HAS_CACHE_LINE_SIZE def_bool y config HAVE_SETUP_PER_CPU_AREA def_bool y config NEED_PER_CPU_EMBED_FIRST_CHUNK def_bool y config NEED_PER_CPU_PAGE_FIRST_CHUNK def_bool y config HAVE_CPUMASK_OF_CPU_MAP def_bool X86_64_SMP config ARCH_HIBERNATION_POSSIBLE def_bool y config ARCH_SUSPEND_POSSIBLE def_bool y config ZONE_DMA32 bool default X86_64 config ARCH_POPULATES_NODE_MAP def_bool y config AUDIT_ARCH bool default X86_64 config ARCH_SUPPORTS_OPTIMIZED_INLINING def_bool y config ARCH_SUPPORTS_DEBUG_PAGEALLOC def_bool y config HAVE_INTEL_TXT def_bool y depends on EXPERIMENTAL && DMAR && ACPI config X86_32_SMP def_bool y depends on X86_32 && SMP config X86_64_SMP def_bool y depends on X86_64 && SMP config X86_HT def_bool y depends on SMP config X86_32_LAZY_GS def_bool y depends on X86_32 && !CC_STACKPROTECTOR config ARCH_HWEIGHT_CFLAGS string default "-fcall-saved-ecx -fcall-saved-edx" if X86_32 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64 config KTIME_SCALAR def_bool X86_32 config ARCH_CPU_PROBE_RELEASE def_bool y depends on HOTPLUG_CPU source "init/Kconfig" source "kernel/Kconfig.freezer" menu "Processor type and features" source "kernel/time/Kconfig" 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. Note that if you say Y here and choose architecture "586" or "Pentium" under "Processor family", the kernel will not work on 486 architectures. Similarly, multiprocessor kernels for the "PPro" architecture may not work on all Pentium based boards. People using multiprocessor machines who say Y here should also say Y to "Enhanced Real Time Clock Support", below. The "Advanced Power Management" code will be disabled if you say Y here. See also , and the SMP-HOWTO available at . If you don't know what to do here, say N. config X86_X2APIC bool "Support x2apic" depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP ---help--- This enables x2apic support on CPUs that have this feature. This allows 32-bit apic IDs (so it can support very large systems), and accesses the local apic via MSRs not via mmio. If you don't know what to do here, say N. config X86_MPPARSE bool "Enable MPS table" if ACPI default y depends on X86_LOCAL_APIC ---help--- For old smp systems that do not have proper acpi support. Newer systems (esp with 64bit cpus) with acpi support, MADT and DSDT will override it config X86_BIGSMP bool "Support for big SMP systems with more than 8 CPUs" depends on X86_32 && SMP ---help--- This option is needed for the systems that have more than 8 CPUs if X86_32 config X86_EXTENDED_PLATFORM bool "Support for extended (non-PC) x86 platforms" default y ---help--- If you disable this option then the kernel will only support standard PC platforms. (which covers the vast majority of systems out there.) If you enable this option then you'll be able to select support for the following (non-PC) 32 bit x86 platforms: AMD Elan NUMAQ (IBM/Sequent) RDC R-321x SoC SGI 320/540 (Visual Workstation) Summit/EXA (IBM x440) Unisys ES7000 IA32 series Moorestown MID devices If you have one of these systems, or if you want to build a generic distribution kernel, say Y here - otherwise say N. endif if X86_64 config X86_EXTENDED_PLATFORM bool "Support for extended (non-PC) x86 platforms" default y ---help--- If you disable this option then the kernel will only support standard PC platforms. (which covers the vast majority of systems out there.) If you enable this option then you'll be able to select support for the following (non-PC) 64 bit x86 platforms: ScaleMP vSMP SGI Ultraviolet If you have one of these systems, or if you want to build a generic distribution kernel, say Y here - otherwise say N. endif # This is an alphabetically sorted list of 64 bit extended platforms # Please maintain the alphabetic order if and when there are additions config X86_VSMP bool "ScaleMP vSMP" select PARAVIRT_GUEST select PARAVIRT depends on X86_64 && PCI depends on X86_EXTENDED_PLATFORM ---help--- Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is supposed to run on these EM64T-based machines. Only choose this option if you have one of these machines. config X86_UV bool "SGI Ultraviolet" depends on X86_64 depends on X86_EXTENDED_PLATFORM depends on NUMA depends on X86_X2APIC ---help--- This option is needed in order to support SGI Ultraviolet systems. If you don't have one of these, you should say N here. # Following is an alphabetically sorted list of 32 bit extended platforms # Please maintain the alphabetic order if and when there are additions config X86_INTEL_CE bool "CE4100 TV platform" depends on PCI depends on PCI_GODIRECT depends on X86_32 depends on X86_EXTENDED_PLATFORM select X86_REBOOTFIXUPS select OF select OF_EARLY_FLATTREE ---help--- Select for the Intel CE media processor (CE4100) SOC. This option compiles in support for the CE4100 SOC for settop boxes and media devices. config X86_MRST bool "Moorestown MID platform" depends on PCI depends on PCI_GOANY depends on X86_32 depends on X86_EXTENDED_PLATFORM depends on X86_IO_APIC select APB_TIMER select I2C select SPI select INTEL_SCU_IPC select X86_PLATFORM_DEVICES ---help--- Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin Internet Device(MID) platform. Moorestown consists of two chips: Lincroft (CPU core, graphics, and memory controller) and Langwell IOH. Unlike standard x86 PCs, Moorestown does not have many legacy devices nor standard legacy replacement devices/features. e.g. Moorestown does not contain i8259, i8254, HPET, legacy BIOS, most of the io ports. config X86_RDC321X bool "RDC R-321x SoC" depends on X86_32 depends on X86_EXTENDED_PLATFORM select M486 select X86_REBOOTFIXUPS ---help--- This option is needed for RDC R-321x system-on-chip, also known as R-8610-(G). If you don't have one of these chips, you should say N here. config X86_32_NON_STANDARD bool "Support non-standard 32-bit SMP architectures" depends on X86_32 && SMP depends on X86_EXTENDED_PLATFORM ---help--- This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default subarchitectures. It is intended for a generic binary kernel. if you select them all, kernel will probe it one by one. and will fallback to default. # Alphabetically sorted list of Non standard 32 bit platforms config X86_NUMAQ bool "NUMAQ (IBM/Sequent)" depends on X86_32_NON_STANDARD depends on PCI select NUMA select X86_MPPARSE ---help--- This option is used for getting Linux to run on a NUMAQ (IBM/Sequent) NUMA multiquad box. This changes the way that processors are bootstrapped, and uses Clustered Logical APIC addressing mode instead of Flat Logical. You will need a new lynxer.elf file to flash your firmware with - send email to . config X86_SUPPORTS_MEMORY_FAILURE def_bool y # MCE code calls memory_failure(): depends on X86_MCE # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: depends on !X86_NUMAQ # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: depends on X86_64 || !SPARSEMEM select ARCH_SUPPORTS_MEMORY_FAILURE config X86_VISWS bool "SGI 320/540 (Visual Workstation)" depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT depends on X86_32_NON_STANDARD ---help--- The SGI Visual Workstation series is an IA32-based workstation based on SGI systems chips with some legacy PC hardware attached. Say Y here to create a kernel to run on the SGI 320 or 540. A kernel compiled for the Visual Workstation will run on general PCs as well. See for details. config X86_SUMMIT bool "Summit/EXA (IBM x440)" depends on X86_32_NON_STANDARD ---help--- This option is needed for IBM systems that use the Summit/EXA chipset. In particular, it is needed for the x440. config X86_ES7000 bool "Unisys ES7000 IA32 series" depends on X86_32_NON_STANDARD && X86_BIGSMP ---help--- Support for Unisys ES7000 systems. Say 'Y' here if this kernel is supposed to run on an IA32-based Unisys ES7000 system. config X86_32_IRIS tristate "Eurobraille/Iris poweroff module" depends on X86_32 ---help--- The Iris machines from EuroBraille do not have APM or ACPI support to shut themselves down properly. A special I/O sequence is needed to do so, which is what this module does at kernel shutdown. This is only for Iris machines from EuroBraille. If unused, say N. config SCHED_OMIT_FRAME_POINTER def_bool y prompt "Single-depth WCHAN output" depends on X86 ---help--- Calculate simpler /proc//wchan values. If this option is disabled then wchan values will recurse back to the caller function. This provides more accurate wchan values, at the expense of slightly more scheduling overhead. If in doubt, say "Y". menuconfig PARAVIRT_GUEST bool "Paravirtualized guest support" ---help--- Say Y here to get to see options related to running Linux under various hypervisors. This option alone does not add any kernel code. If you say N, all options in this submenu will be skipped and disabled. if PARAVIRT_GUEST source "arch/x86/xen/Kconfig" config KVM_CLOCK bool "KVM paravirtualized clock" select PARAVIRT select PARAVIRT_CLOCK ---help--- Turning on this option will allow you to run a paravirtualized clock when running over the KVM hypervisor. Instead of relying on a PIT (or probably other) emulation by the underlying device model, the host provides the guest with timing infrastructure such as time of day, and system time config KVM_GUEST bool "KVM Guest support" select PARAVIRT ---help--- This option enables various optimizations for running under the KVM hypervisor. source "arch/x86/lguest/Kconfig" config PARAVIRT bool "Enable paravirtualization code" ---help--- This changes the kernel so it can modify itself when it is run under a hypervisor, potentially improving performance significantly over full virtualization. However, when run without a hypervisor the kernel is theoretically slower and slightly larger. config PARAVIRT_SPINLOCKS bool "Paravirtualization layer for spinlocks" depends on PARAVIRT && SMP && EXPERIMENTAL ---help--- Paravirtualized spinlocks allow a pvops backend to replace the spinlock implementation with something virtualization-friendly (for example, block the virtual CPU rather than spinning). Unfortunately the downside is an up to 5% performance hit on native kernels, with various workloads. If you are unsure how to answer this question, answer N. config PARAVIRT_CLOCK bool endif config PARAVIRT_DEBUG bool "paravirt-ops debugging" depends on PARAVIRT && DEBUG_KERNEL ---help--- Enable to debug paravirt_ops internals. Specifically, BUG if a paravirt_op is missing when it is called. config NO_BOOTMEM def_bool y config MEMTEST bool "Memtest" ---help--- This option adds a kernel parameter 'memtest', which allows memtest to be set. memtest=0, mean disabled; -- default memtest=1, mean do 1 test pattern; ... memtest=4, mean do 4 test patterns. If you are unsure how to answer this question, answer N. config X86_SUMMIT_NUMA def_bool y depends on X86_32 && NUMA && X86_32_NON_STANDARD config X86_CYCLONE_TIMER def_bool y depends on X86_32_NON_STANDARD source "arch/x86/Kconfig.cpu" config HPET_TIMER def_bool X86_64 prompt "HPET Timer Support" if X86_32 ---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. HPET is the next generation timer replacing legacy 8254s. The HPET provides a stable time base on SMP systems, unlike the TSC, but it is more expensive to access, as it is off-chip. You can find the HPET spec at . You can safely choose Y here. However, HPET will only be activated if the platform and the BIOS support this feature. Otherwise the 8254 will be used for timing services. Choose N to continue using the legacy 8254 timer. config HPET_EMULATE_RTC def_bool y depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) config APB_TIMER def_bool y if MRST prompt "Langwell APB Timer Support" if X86_MRST help APB timer is the replacement for 8254, HPET on X86 MID platforms. The APBT provides a stable time base on SMP systems, unlike the TSC, but it is more expensive to access, as it is off-chip. APB timers are always running regardless of CPU C states, they are used as per CPU clockevent device when possible. # Mark as expert because too many people got it wrong. # The code disables itself when not needed. config DMI default y bool "Enable DMI scanning" if EXPERT ---help--- Enabled scanning of DMI to identify machine quirks. Say Y here unless you have verified that your setup is not affected by entries in the DMI blacklist. Required by PNP BIOS code. config GART_IOMMU bool "GART IOMMU support" if EXPERT default y select SWIOTLB depends on X86_64 && PCI && AMD_NB ---help--- Support for full DMA access of devices with 32bit memory access only on systems with more than 3GB. This is usually needed for USB, sound, many IDE/SATA chipsets and some other devices. Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART based hardware IOMMU and a software bounce buffer based IOMMU used on Intel systems and as fallback. The code is only active when needed (enough memory and limited device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified too. config CALGARY_IOMMU bool "IBM Calgary IOMMU support" select SWIOTLB depends on X86_64 && PCI && EXPERIMENTAL ---help--- Support for hardware IOMMUs in IBM's xSeries x366 and x460 systems. Needed to run systems with more than 3GB of memory properly with 32-bit PCI devices that do not support DAC (Double Address Cycle). Calgary also supports bus level isolation, where all DMAs pass through the IOMMU. This prevents them from going anywhere except their intended destination. This catches hard-to-find kernel bugs and mis-behaving drivers and devices that do not use the DMA-API properly to set up their DMA buffers. The IOMMU can be turned off at boot time with the iommu=off parameter. Normally the kernel will make the right choice by itself. If unsure, say Y. config CALGARY_IOMMU_ENABLED_BY_DEFAULT def_bool y prompt "Should Calgary be enabled by default?" depends on CALGARY_IOMMU ---help--- Should Calgary be enabled by default? if you choose 'y', Calgary will be used (if it exists). If you choose 'n', Calgary will not be used even if it exists. If you choose 'n' and would like to use Calgary anyway, pass 'iommu=calgary' on the kernel command line. If unsure, say Y. config AMD_IOMMU bool "AMD IOMMU support" select SWIOTLB select PCI_MSI select PCI_IOV depends on X86_64 && PCI && ACPI ---help--- With this option you can enable support for AMD IOMMU hardware in your system. An IOMMU is a hardware component which provides remapping of DMA memory accesses from devices. With an AMD IOMMU you can isolate the the DMA memory of different devices and protect the system from misbehaving device drivers or hardware. You can find out if your system has an AMD IOMMU if you look into your BIOS for an option to enable it or if you have an IVRS ACPI table. config AMD_IOMMU_STATS bool "Export AMD IOMMU statistics to debugfs" depends on AMD_IOMMU select DEBUG_FS ---help--- This option enables code in the AMD IOMMU driver to collect various statistics about whats happening in the driver and exports that information to userspace via debugfs. If unsure, say N. # need this always selected by IOMMU for the VIA workaround config SWIOTLB def_bool y if X86_64 ---help--- Support for software bounce buffers used on x86-64 systems which don't have a hardware IOMMU (e.g. the current generation of Intel's x86-64 CPUs). Using this PCI devices which can only access 32-bits of memory can be used on systems with more than 3 GB of memory. If unsure, say Y. config IOMMU_HELPER def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU) config IOMMU_API def_bool (AMD_IOMMU || DMAR) config MAXSMP bool "Enable Maximum number of SMP Processors and NUMA Nodes" depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL select CPUMASK_OFFSTACK ---help--- Enable maximum number of CPUS and NUMA Nodes for this architecture. If unsure, say N. config NR_CPUS int "Maximum number of CPUs" if SMP && !MAXSMP range 2 8 if SMP && X86_32 && !X86_BIGSMP range 2 512 if SMP && !MAXSMP default "1" if !SMP default "4096" if MAXSMP default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000) default "8" if SMP ---help--- This allows you to specify the maximum number of CPUs which this kernel will support. The maximum supported value is 512 and the minimum value which makes sense is 2. This is purely to save memory - each supported CPU adds approximately eight kilobytes to the kernel image. config SCHED_SMT bool "SMT (Hyperthreading) scheduler support" depends on X86_HT ---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 SCHED_MC def_bool y prompt "Multi-core scheduler support" depends on X86_HT ---help--- Multi-core scheduler support improves the CPU scheduler's decision making when dealing with multi-core CPU chips at a cost of slightly increased overhead in some places. If unsure say N here. config IRQ_TIME_ACCOUNTING bool "Fine granularity task level IRQ time accounting" default n ---help--- Select this option to enable fine granularity task irq time accounting. This is done by reading a timestamp on each transitions between softirq and hardirq state, so there can be a small performance impact. If in doubt, say N here. source "kernel/Kconfig.preempt" config X86_UP_APIC bool "Local APIC support on uniprocessors" depends on X86_32 && !SMP && !X86_32_NON_STANDARD ---help--- A local APIC (Advanced Programmable Interrupt Controller) is an integrated interrupt controller in the CPU. If you have a single-CPU system which has a processor with a local APIC, you can say Y here to enable and use it. If you say Y here even though your machine doesn't have a local APIC, then the kernel will still run with no slowdown at all. The local APIC supports CPU-generated self-interrupts (timer, performance counters), and the NMI watchdog which detects hard lockups. config X86_UP_IOAPIC bool "IO-APIC support on uniprocessors" depends on X86_UP_APIC ---help--- An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an SMP-capable replacement for PC-style interrupt controllers. Most SMP systems and many recent uniprocessor systems have one. If you have a single-CPU system with an IO-APIC, you can say Y here to use it. If you say Y here even though your machine doesn't have an IO-APIC, then the kernel will still run with no slowdown at all. config X86_LOCAL_APIC def_bool y depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC config X86_IO_APIC def_bool y depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC config X86_VISWS_APIC def_bool y depends on X86_32 && X86_VISWS config X86_REROUTE_FOR_BROKEN_BOOT_IRQS bool "Reroute for broken boot IRQs" depends on X86_IO_APIC ---help--- This option enables a workaround that fixes a source of spurious interrupts. This is recommended when threaded interrupt handling is used on systems where the generation of superfluous "boot interrupts" cannot be disabled. Some chipsets generate a legacy INTx "boot IRQ" when the IRQ entry in the chipset's IO-APIC is masked (as, e.g. the RT kernel does during interrupt handling). On chipsets where this boot IRQ generation cannot be disabled, this workaround keeps the original IRQ line masked so that only the equivalent "boot IRQ" is delivered to the CPUs. The workaround also tells the kernel to set up the IRQ handler on the boot IRQ line. In this way only one interrupt is delivered to the kernel. Otherwise the spurious second interrupt may cause the kernel to bring down (vital) interrupt lines. Only affects "broken" chipsets. Interrupt sharing may be increased on these systems. config X86_MCE bool "Machine Check / overheating reporting" ---help--- Machine Check support allows the processor to notify the kernel if it detects a problem (e.g. overheating, data corruption). The action the kernel takes depends on the severity of the problem, ranging from warning messages to halting the machine. config X86_MCE_INTEL def_bool y prompt "Intel MCE features" depends on X86_MCE && X86_LOCAL_APIC ---help--- Additional support for intel specific MCE features such as the thermal monitor. config X86_MCE_AMD def_bool y prompt "AMD MCE features" depends on X86_MCE && X86_LOCAL_APIC ---help--- Additional support for AMD specific MCE features such as the DRAM Error Threshold. config X86_ANCIENT_MCE bool "Support for old Pentium 5 / WinChip machine checks" depends on X86_32 && X86_MCE ---help--- Include support for machine check handling on old Pentium 5 or WinChip systems. These typically need to be enabled explicitely on the command line. config X86_MCE_THRESHOLD depends on X86_MCE_AMD || X86_MCE_INTEL def_bool y config X86_MCE_INJECT depends on X86_MCE tristate "Machine check injector support" ---help--- Provide support for injecting machine checks for testing purposes. If you don't know what a machine check is and you don't do kernel QA it is safe to say n. config X86_THERMAL_VECTOR def_bool y depends on X86_MCE_INTEL config VM86 bool "Enable VM86 support" if EXPERT default y depends on X86_32 ---help--- This option is required by programs like DOSEMU to run 16-bit legacy code on X86 processors. It also may be needed by software like XFree86 to initialize some video cards via BIOS. Disabling this option saves about 6k. config TOSHIBA tristate "Toshiba Laptop support" depends on X86_32 ---help--- This adds a driver to safely access the System Management Mode of the CPU on Toshiba portables with a genuine Toshiba BIOS. It does not work on models with a Phoenix BIOS. The System Management Mode is used to set the BIOS and power saving options on Toshiba portables. For information on utilities to make use of this driver see the Toshiba Linux utilities web site at: . Say Y if you intend to run this kernel on a Toshiba portable. Say N otherwise. config I8K tristate "Dell laptop support" select HWMON ---help--- This adds a driver to safely access the System Management Mode of the CPU on the Dell Inspiron 8000. The System Management Mode is used to read cpu temperature and cooling fan status and to control the fans on the I8K portables. This driver has been tested only on the Inspiron 8000 but it may also work with other Dell laptops. You can force loading on other models by passing the parameter `force=1' to the module. Use at your own risk. For information on utilities to make use of this driver see the I8K Linux utilities web site at: Say Y if you intend to run this kernel on a Dell Inspiron 8000. Say N otherwise. config X86_REBOOTFIXUPS bool "Enable X86 board specific fixups for reboot" depends on X86_32 ---help--- This enables chipset and/or board specific fixups to be done in order to get reboot to work correctly. This is only needed on some combinations of hardware and BIOS. The symptom, for which this config is intended, is when reboot ends with a stalled/hung system. Currently, the only fixup is for the Geode machines using CS5530A and CS5536 chipsets and the RDC R-321x SoC. Say Y if you want to enable the fixup. Currently, it's safe to enable this option even if you don't need it. Say N otherwise. config MICROCODE tristate "/dev/cpu/microcode - microcode support" select FW_LOADER ---help--- If you say Y here, you will be able to update the microcode on certain Intel and AMD processors. The Intel support is for the IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The AMD support is for family 0x10 and 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra. You will obviously need the actual microcode binary data itself which is not shipped with the Linux kernel. This option selects the general module only, you need to select at least one vendor specific module as well. To compile this driver as a module, choose M here: the module will be called microcode. config MICROCODE_INTEL bool "Intel microcode patch loading support" depends on MICROCODE default MICROCODE select FW_LOADER ---help--- This options enables microcode patch loading support for Intel processors. For latest news and information on obtaining all the required Intel ingredients for this driver, check: . config MICROCODE_AMD bool "AMD microcode patch loading support" depends on MICROCODE select FW_LOADER ---help--- If you select this option, microcode patch loading support for AMD processors will be enabled. config MICROCODE_OLD_INTERFACE def_bool y depends on MICROCODE 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. choice prompt "High Memory Support" default HIGHMEM64G if X86_NUMAQ default HIGHMEM4G depends on X86_32 config NOHIGHMEM bool "off" depends on !X86_NUMAQ ---help--- Linux can use up to 64 Gigabytes of physical memory on x86 systems. However, the address space of 32-bit x86 processors is only 4 Gigabytes large. That means that, if you have a large amount of physical memory, not all of it can be "permanently mapped" by the kernel. The physical memory that's not permanently mapped is called "high memory". If you are compiling a kernel which will never run on a machine with more than 1 Gigabyte total physical RAM, answer "off" here (default choice and suitable for most users). This will result in a "3GB/1GB" split: 3GB are mapped so that each process sees a 3GB virtual memory space and the remaining part of the 4GB virtual memory space is used by the kernel to permanently map as much physical memory as possible. If the machine has between 1 and 4 Gigabytes physical RAM, then answer "4GB" here. If more than 4 Gigabytes is used then answer "64GB" here. This selection turns Intel PAE (Physical Address Extension) mode on. PAE implements 3-level paging on IA32 processors. PAE is fully supported by Linux, PAE mode is implemented on all recent Intel processors (Pentium Pro and better). NOTE: If you say "64GB" here, then the kernel will not boot on CPUs that don't support PAE! The actual amount of total physical memory will either be auto detected or can be forced by using a kernel command line option such as "mem=256M". (Try "man bootparam" or see the documentation of your boot loader (lilo or loadlin) about how to pass options to the kernel at boot time.) If unsure, say "off". config HIGHMEM4G bool "4GB" depends on !X86_NUMAQ ---help--- Select this if you have a 32-bit processor and between 1 and 4 gigabytes of physical RAM. config HIGHMEM64G bool "64GB" depends on !M386 && !M486 select X86_PAE ---help--- Select this if you have a 32-bit processor and more than 4 gigabytes of physical RAM. endchoice choice depends on EXPERIMENTAL prompt "Memory split" if EXPERT default VMSPLIT_3G depends on X86_32 ---help--- Select the desired split between kernel and user memory. If the address range available to the kernel is less than the physical memory installed, the remaining memory will be available as "high memory". Accessing high memory is a little more costly than low memory, as it needs to be mapped into the kernel first. Note that increasing the kernel address space limits the range available to user programs, making the address space there tighter. Selecting anything other than the default 3G/1G split will also likely make your kernel incompatible with binary-only kernel modules. If you are not absolutely sure what you are doing, leave this option alone! config VMSPLIT_3G bool "3G/1G user/kernel split" config VMSPLIT_3G_OPT depends on !X86_PAE bool "3G/1G user/kernel split (for full 1G low memory)" config VMSPLIT_2G bool "2G/2G user/kernel split" config VMSPLIT_2G_OPT depends on !X86_PAE bool "2G/2G user/kernel split (for full 2G low memory)" config VMSPLIT_1G bool "1G/3G user/kernel split" endchoice config PAGE_OFFSET hex default 0xB0000000 if VMSPLIT_3G_OPT default 0x80000000 if VMSPLIT_2G default 0x78000000 if VMSPLIT_2G_OPT default 0x40000000 if VMSPLIT_1G default 0xC0000000 depends on X86_32 config HIGHMEM def_bool y depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) config X86_PAE bool "PAE (Physical Address Extension) Support" depends on X86_32 && !HIGHMEM4G ---help--- PAE is required for NX support, and furthermore enables larger swapspace support for non-overcommit purposes. It has the cost of more pagetable lookup overhead, and also consumes more pagetable space per process. config ARCH_PHYS_ADDR_T_64BIT def_bool X86_64 || X86_PAE config ARCH_DMA_ADDR_T_64BIT def_bool X86_64 || HIGHMEM64G config DIRECT_GBPAGES bool "Enable 1GB pages for kernel pagetables" if EXPERT default y depends on X86_64 ---help--- Allow the kernel linear mapping to use 1GB pages on CPUs that support it. This can improve the kernel's performance a tiny bit by reducing TLB pressure. If in doubt, say "Y". # Common NUMA Features config NUMA bool "Numa Memory Allocation and Scheduler Support" depends on SMP depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL) default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP) ---help--- Enable NUMA (Non Uniform Memory Access) support. 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. For 64-bit this is recommended if the system is Intel Core i7 (or later), AMD Opteron, or EM64T NUMA. For 32-bit this is only needed on (rare) 32-bit-only platforms that support NUMA topologies, such as NUMAQ / Summit, or if you boot a 32-bit kernel on a 64-bit NUMA platform. Otherwise, you should say N. comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI" depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI) config AMD_NUMA def_bool y prompt "Old style AMD Opteron NUMA detection" depends on NUMA && PCI ---help--- Enable AMD NUMA node topology detection. You should say Y here if you have a multi processor AMD system. This uses an old method to read the NUMA configuration directly from the builtin Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, which also takes priority if both are compiled in. config X86_64_ACPI_NUMA def_bool y prompt "ACPI NUMA detection" depends on X86_64 && NUMA && ACPI && PCI select ACPI_NUMA ---help--- Enable ACPI SRAT based node topology detection. # Some NUMA nodes have memory ranges that span # other nodes. Even though a pfn is valid and # between a node's start and end pfns, it may not # reside on that node. See memmap_init_zone() # for details. config NODES_SPAN_OTHER_NODES def_bool y depends on X86_64_ACPI_NUMA config NUMA_EMU bool "NUMA emulation" depends on NUMA ---help--- Enable NUMA emulation. A flat machine will be split into virtual nodes when booted with "numa=fake=N", where N is the number of nodes. This is only useful for debugging. config NODES_SHIFT int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP range 1 10 default "10" if MAXSMP default "6" if X86_64 default "4" if X86_NUMAQ default "3" depends on NEED_MULTIPLE_NODES ---help--- Specify the maximum number of NUMA Nodes available on the target system. Increases memory reserved to accommodate various tables. config HAVE_ARCH_BOOTMEM def_bool y depends on X86_32 && NUMA config HAVE_ARCH_ALLOC_REMAP def_bool y depends on X86_32 && NUMA config ARCH_HAVE_MEMORY_PRESENT def_bool y depends on X86_32 && DISCONTIGMEM config NEED_NODE_MEMMAP_SIZE def_bool y depends on X86_32 && (DISCONTIGMEM || SPARSEMEM) config ARCH_FLATMEM_ENABLE def_bool y depends on X86_32 && !NUMA config ARCH_DISCONTIGMEM_ENABLE def_bool y depends on NUMA && X86_32 config ARCH_DISCONTIGMEM_DEFAULT def_bool y depends on NUMA && X86_32 config ARCH_SPARSEMEM_ENABLE def_bool y depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD select SPARSEMEM_STATIC if X86_32 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 config ARCH_SPARSEMEM_DEFAULT def_bool y depends on X86_64 config ARCH_SELECT_MEMORY_MODEL def_bool y depends on ARCH_SPARSEMEM_ENABLE config ARCH_MEMORY_PROBE def_bool X86_64 depends on MEMORY_HOTPLUG config ARCH_PROC_KCORE_TEXT def_bool y depends on X86_64 && PROC_KCORE config ILLEGAL_POINTER_VALUE hex default 0 if X86_32 default 0xdead000000000000 if X86_64 source "mm/Kconfig" config HIGHPTE bool "Allocate 3rd-level pagetables from highmem" depends on HIGHMEM ---help--- The VM uses one page table entry for each page of physical memory. For systems with a lot of RAM, this can be wasteful of precious low memory. Setting this option will put user-space page table entries in high memory. config X86_CHECK_BIOS_CORRUPTION bool "Check for low memory corruption" ---help--- Periodically check for memory corruption in low memory, which is suspected to be caused by BIOS. Even when enabled in the configuration, it is disabled at runtime. Enable it by setting "memory_corruption_check=1" on the kernel command line. By default it scans the low 64k of memory every 60 seconds; see the memory_corruption_check_size and memory_corruption_check_period parameters in Documentation/kernel-parameters.txt to adjust this. When enabled with the default parameters, this option has almost no overhead, as it reserves a relatively small amount of memory and scans it infrequently. It both detects corruption and prevents it from affecting the running system. It is, however, intended as a diagnostic tool; if repeatable BIOS-originated corruption always affects the same memory, you can use memmap= to prevent the kernel from using that memory. config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK bool "Set the default setting of memory_corruption_check" depends on X86_CHECK_BIOS_CORRUPTION default y ---help--- Set whether the default state of memory_corruption_check is on or off. config X86_RESERVE_LOW int "Amount of low memory, in kilobytes, to reserve for the BIOS" default 64 range 4 640 ---help--- Specify the amount of low memory to reserve for the BIOS. The first page contains BIOS data structures that the kernel must not use, so that page must always be reserved. By default we reserve the first 64K of physical RAM, as a number of BIOSes are known to corrupt that memory range during events such as suspend/resume or monitor cable insertion, so it must not be used by the kernel. You can set this to 4 if you are absolutely sure that you trust the BIOS to get all its memory reservations and usages right. If you know your BIOS have problems beyond the default 64K area, you can set this to 640 to avoid using the entire low memory range. If you have doubts about the BIOS (e.g. suspend/resume does not work or there's kernel crashes after certain hardware hotplug events) then you might want to enable X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical corruption patterns. Leave this to the default value of 64 if you are unsure. config MATH_EMULATION bool prompt "Math emulation" if X86_32 ---help--- Linux can emulate a math coprocessor (used for floating point operations) if you don't have one. 486DX and Pentium processors have a math coprocessor built in, 486SX and 386 do not, unless you added a 487DX or 387, respectively. (The messages during boot time can give you some hints here ["man dmesg"].) Everyone needs either a coprocessor or this emulation. If you don't have a math coprocessor, you need to say Y here; if you say Y here even though you have a coprocessor, the coprocessor will be used nevertheless. (This behavior can be changed with the kernel command line option "no387", which comes handy if your coprocessor is broken. Try "man bootparam" or see the documentation of your boot loader (lilo or loadlin) about how to pass options to the kernel at boot time.) This means that it is a good idea to say Y here if you intend to use this kernel on different machines. More information about the internals of the Linux math coprocessor emulation can be found in . If you are not sure, say Y; apart from resulting in a 66 KB bigger kernel, it won't hurt. config MTRR def_bool y prompt "MTRR (Memory Type Range Register) support" if EXPERT ---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: The Cyrix 6x86, 6x86MX and M II processors have Address Range Registers (ARRs) which provide a similar functionality to MTRRs. For these, the ARRs are used to emulate the MTRRs. The AMD K6-2 (stepping 8 and above) and K6-3 processors have two MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. All of these processors are supported by this code and it makes sense to say Y here if you have one of them. 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. You can safely say Y even if your machine doesn't have MTRRs, you'll just add about 9 KB to your kernel. See for more information. config MTRR_SANITIZER def_bool y prompt "MTRR cleanup support" depends on MTRR ---help--- Convert MTRR layout from continuous to discrete, so X drivers can add writeback entries. Can be disabled with disable_mtrr_cleanup on the kernel command line. The largest mtrr entry size for a continuous block can be set with mtrr_chunk_size. If unsure, say Y. config MTRR_SANITIZER_ENABLE_DEFAULT int "MTRR cleanup enable value (0-1)" range 0 1 default "0" depends on MTRR_SANITIZER ---help--- Enable mtrr cleanup default value config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT int "MTRR cleanup spare reg num (0-7)" range 0 7 default "1" depends on MTRR_SANITIZER ---help--- mtrr cleanup spare entries default, it can be changed via mtrr_spare_reg_nr=N on the kernel command line. config X86_PAT def_bool y prompt "x86 PAT support" if EXPERT depends on MTRR ---help--- Use PAT attributes to setup page level cache control. PATs are the modern equivalents of MTRRs and are much more flexible than MTRRs. Say N here if you see bootup problems (boot crash, boot hang, spontaneous reboots) or a non-working video driver. If unsure, say Y. config ARCH_USES_PG_UNCACHED def_bool y depends on X86_PAT config EFI bool "EFI runtime service support" depends on ACPI ---help--- This enables the kernel to use EFI runtime services that are available (such as the EFI variable services). This option is only useful on systems that have EFI firmware. In addition, you should use the latest ELILO loader available at in order to take advantage of EFI runtime services. However, even with this option, the resultant kernel should continue to boot on existing non-EFI platforms. config SECCOMP def_bool y prompt "Enable seccomp to safely compute untrusted bytecode" ---help--- This kernel feature is useful for number crunching applications that may need to compute untrusted bytecode during their execution. By using pipes or other transports made available to the process as file descriptors supporting the read/write syscalls, it's possible to isolate those applications in their own address space using seccomp. Once seccomp is enabled via prctl(PR_SET_SECCOMP), it cannot be disabled and the task is only allowed to execute a few safe syscalls defined by each seccomp mode. If unsure, say Y. Only embedded should say N here. config CC_STACKPROTECTOR bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)" ---help--- This option turns on the -fstack-protector GCC feature. This feature puts, at the beginning of functions, a canary value on the stack just before the return address, and validates the value just before actually returning. Stack based buffer overflows (that need to overwrite this return address) now also overwrite the canary, which gets detected and the attack is then neutralized via a kernel panic. This feature requires gcc version 4.2 or above, or a distribution gcc with the feature backported. Older versions are automatically detected and for those versions, this configuration option is ignored. (and a warning is printed during bootup) source kernel/Kconfig.hz config KEXEC bool "kexec system call" ---help--- kexec is a system call that implements the ability to shutdown your current kernel, and to start another kernel. It is like a reboot but it is independent of the system firmware. And like a reboot you can start any kernel with it, not just Linux. The name comes from the similarity to the exec system call. It is an ongoing process to be certain the hardware in a machine is properly shutdown, so do not be surprised if this code does not initially work for you. It may help to enable device hotplugging support. As of this writing the exact hardware interface is strongly in flux, so no good recommendation can be made. config CRASH_DUMP bool "kernel crash dumps" depends on X86_64 || (X86_32 && HIGHMEM) ---help--- Generate crash dump after being started by kexec. This should be normally only set in special crash dump kernels which are loaded in the main kernel with kexec-tools into a specially reserved region and then later executed after a crash by kdump/kexec. The crash dump kernel must be compiled to a memory address not used by the main kernel or BIOS using PHYSICAL_START, or it must be built as a relocatable image (CONFIG_RELOCATABLE=y). For more details see Documentation/kdump/kdump.txt config KEXEC_JUMP bool "kexec jump (EXPERIMENTAL)" depends on EXPERIMENTAL depends on KEXEC && HIBERNATION ---help--- Jump between original kernel and kexeced kernel and invoke code in physical address mode via KEXEC config PHYSICAL_START hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) default "0x1000000" ---help--- This gives the physical address where the kernel is loaded. If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then bzImage will decompress itself to above physical address and run from there. Otherwise, bzImage will run from the address where it has been loaded by the boot loader and will ignore above physical address. In normal kdump cases one does not have to set/change this option as now bzImage can be compiled as a completely relocatable image (CONFIG_RELOCATABLE=y) and be used to load and run from a different address. This option is mainly useful for the folks who don't want to use a bzImage for capturing the crash dump and want to use a vmlinux instead. vmlinux is not relocatable hence a kernel needs to be specifically compiled to run from a specific memory area (normally a reserved region) and this option comes handy. So if you are using bzImage for capturing the crash dump, leave the value here unchanged to 0x1000000 and set CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux for capturing the crash dump change this value to start of the reserved region. In other words, it can be set based on the "X" value as specified in the "crashkernel=YM@XM" command line boot parameter passed to the panic-ed kernel. Please take a look at Documentation/kdump/kdump.txt for more details about crash dumps. Usage of bzImage for capturing the crash dump is recommended as one does not have to build two kernels. Same kernel can be used as production kernel and capture kernel. Above option should have gone away after relocatable bzImage support is introduced. But it is present because there are users out there who continue to use vmlinux for dump capture. This option should go away down the line. Don't change this unless you know what you are doing. config RELOCATABLE bool "Build a relocatable kernel" default y ---help--- This builds a kernel image that retains relocation information so it can be loaded someplace besides the default 1MB. The relocations tend to make the kernel binary about 10% larger, but are discarded at runtime. One use is for the kexec on panic case where the recovery kernel must live at a different physical address than the primary kernel. Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address it has been loaded at and the compile time physical address (CONFIG_PHYSICAL_START) is ignored. # Relocation on x86-32 needs some additional build support config X86_NEED_RELOCS def_bool y depends on X86_32 && RELOCATABLE config PHYSICAL_ALIGN hex "Alignment value to which kernel should be aligned" if X86_32 default "0x1000000" range 0x2000 0x1000000 ---help--- This value puts the alignment restrictions on physical address where kernel is loaded and run from. Kernel is compiled for an address which meets above alignment restriction. If bootloader loads the kernel at a non-aligned address and CONFIG_RELOCATABLE is set, kernel will move itself to nearest address aligned to above value and run from there. If bootloader loads the kernel at a non-aligned address and CONFIG_RELOCATABLE is not set, kernel will ignore the run time load address and decompress itself to the address it has been compiled for and run from there. The address for which kernel is compiled already meets above alignment restrictions. Hence the end result is that kernel runs from a physical address meeting above alignment restrictions. Don't change this unless you know what you are doing. config HOTPLUG_CPU bool "Support for hot-pluggable CPUs" depends on SMP && HOTPLUG ---help--- Say Y here to allow turning CPUs off and on. CPUs can be controlled through /sys/devices/system/cpu. ( Note: power management support will enable this option automatically on SMP systems. ) Say N if you want to disable CPU hotplug. config COMPAT_VDSO def_bool y prompt "Compat VDSO support" depends on X86_32 || IA32_EMULATION ---help--- Map the 32-bit VDSO to the predictable old-style address too. Say N here if you are running a sufficiently recent glibc version (2.3.3 or later), to remove the high-mapped VDSO mapping and to exclusively use the randomized VDSO. If unsure, say Y. config CMDLINE_BOOL bool "Built-in kernel command line" ---help--- Allow for specifying boot arguments to the kernel at build time. On some systems (e.g. embedded ones), it is necessary or convenient to provide some or all of the kernel boot arguments with the kernel itself (that is, to not rely on the boot loader to provide them.) To compile command line arguments into the kernel, set this option to 'Y', then fill in the the boot arguments in CONFIG_CMDLINE. Systems with fully functional boot loaders (i.e. non-embedded) should leave this option set to 'N'. config CMDLINE string "Built-in kernel command string" depends on CMDLINE_BOOL default "" ---help--- Enter arguments here that should be compiled into the kernel image and used at boot time. If the boot loader provides a command line at boot time, it is appended to this string to form the full kernel command line, when the system boots. However, you can use the CONFIG_CMDLINE_OVERRIDE option to change this behavior. In most cases, the command line (whether built-in or provided by the boot loader) should specify the device for the root file system. config CMDLINE_OVERRIDE bool "Built-in command line overrides boot loader arguments" depends on CMDLINE_BOOL ---help--- Set this option to 'Y' to have the kernel ignore the boot loader command line, and use ONLY the built-in command line. This is used to work around broken boot loaders. This should be set to 'N' under normal conditions. endmenu config ARCH_ENABLE_MEMORY_HOTPLUG def_bool y depends on X86_64 || (X86_32 && HIGHMEM) config ARCH_ENABLE_MEMORY_HOTREMOVE def_bool y depends on MEMORY_HOTPLUG config USE_PERCPU_NUMA_NODE_ID def_bool y depends on NUMA menu "Power management and ACPI options" config ARCH_HIBERNATION_HEADER def_bool y depends on X86_64 && HIBERNATION source "kernel/power/Kconfig" source "drivers/acpi/Kconfig" source "drivers/sfi/Kconfig" config X86_APM_BOOT def_bool y depends on APM || APM_MODULE menuconfig APM tristate "APM (Advanced Power Management) BIOS support" depends on X86_32 && PM_SLEEP ---help--- APM is a BIOS specification for saving power using several different techniques. This is mostly useful for battery powered laptops with APM compliant BIOSes. If you say Y here, the system time will be reset after a RESUME operation, the /proc/apm device will provide battery status information, and user-space programs will receive notification of APM "events" (e.g. battery status change). If you select "Y" here, you can disable actual use of the APM BIOS by passing the "apm=off" option to the kernel at boot time. Note that the APM support is almost completely disabled for machines with more than one CPU. In order to use APM, you will need supporting software. For location and more information, read and the Battery Powered Linux mini-HOWTO, available from . This driver does not spin down disk drives (see the hdparm(8) manpage ("man 8 hdparm") for that), and it doesn't turn off VESA-compliant "green" monitors. This driver does not support the TI 4000M TravelMate and the ACER 486/DX4/75 because they don't have compliant BIOSes. Many "green" desktop machines also don't have compliant BIOSes, and this driver may cause those machines to panic during the boot phase. Generally, if you don't have a battery in your machine, there isn't much point in using this driver and you should say N. If you get random kernel OOPSes or reboots that don't seem to be related to anything, try disabling/enabling this option (or disabling/enabling APM in your BIOS). Some other things you should try when experiencing seemingly random, "weird" problems: 1) make sure that you have enough swap space and that it is enabled. 2) pass the "no-hlt" option to the kernel 3) switch on floating point emulation in the kernel and pass the "no387" option to the kernel 4) pass the "floppy=nodma" option to the kernel 5) pass the "mem=4M" option to the kernel (thereby disabling all but the first 4 MB of RAM) 6) make sure that the CPU is not over clocked. 7) read the sig11 FAQ at 8) disable the cache from your BIOS settings 9) install a fan for the video card or exchange video RAM 10) install a better fan for the CPU 11) exchange RAM chips 12) exchange the motherboard. To compile this driver as a module, choose M here: the module will be called apm. if APM config APM_IGNORE_USER_SUSPEND bool "Ignore USER SUSPEND" ---help--- This option will ignore USER SUSPEND requests. On machines with a compliant APM BIOS, you want to say N. However, on the NEC Versa M series notebooks, it is necessary to say Y because of a BIOS bug. config APM_DO_ENABLE bool "Enable PM at boot time" ---help--- Enable APM features at boot time. From page 36 of the APM BIOS specification: "When disabled, the APM BIOS does not automatically power manage devices, enter the Standby State, enter the Suspend State, or take power saving steps in response to CPU Idle calls." This driver will make CPU Idle calls when Linux is idle (unless this feature is turned off -- see "Do CPU IDLE calls", below). This should always save battery power, but more complicated APM features will be dependent on your BIOS implementation. You may need to turn this option off if your computer hangs at boot time when using APM support, or if it beeps continuously instead of suspending. Turn this off if you have a NEC UltraLite Versa 33/C or a Toshiba T400CDT. This is off by default since most machines do fine without this feature. config APM_CPU_IDLE bool "Make CPU Idle calls when idle" ---help--- Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. On some machines, this can activate improved power savings, such as a slowed CPU clock rate, when the machine is idle. These idle calls are made after the idle loop has run for some length of time (e.g., 333 mS). On some machines, this will cause a hang at boot time or whenever the CPU becomes idle. (On machines with more than one CPU, this option does nothing.) config APM_DISPLAY_BLANK bool "Enable console blanking using APM" ---help--- Enable console blanking using the APM. Some laptops can use this to turn off the LCD backlight when the screen blanker of the Linux virtual console blanks the screen. Note that this is only used by the virtual console screen blanker, and won't turn off the backlight when using the X Window system. This also doesn't have anything to do with your VESA-compliant power-saving monitor. Further, this option doesn't work for all laptops -- it might not turn off your backlight at all, or it might print a lot of errors to the console, especially if you are using gpm. config APM_ALLOW_INTS bool "Allow interrupts during APM BIOS calls" ---help--- Normally we disable external interrupts while we are making calls to the APM BIOS as a measure to lessen the effects of a badly behaving BIOS implementation. The BIOS should reenable interrupts if it needs to. Unfortunately, some BIOSes do not -- especially those in many of the newer IBM Thinkpads. If you experience hangs when you suspend, try setting this to Y. Otherwise, say N. endif # APM source "drivers/cpufreq/Kconfig" source "drivers/cpuidle/Kconfig" source "drivers/idle/Kconfig" endmenu menu "Bus options (PCI etc.)" config PCI bool "PCI support" default y select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC) ---help--- Find out whether you have a PCI motherboard. PCI is the name of a bus system, i.e. the way the CPU talks to the other stuff inside your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or VESA. If you have PCI, say Y, otherwise N. choice prompt "PCI access mode" depends on X86_32 && PCI default PCI_GOANY ---help--- On PCI systems, the BIOS can be used to detect the PCI devices and determine their configuration. However, some old PCI motherboards have BIOS bugs and may crash if this is done. Also, some embedded PCI-based systems don't have any BIOS at all. Linux can also try to detect the PCI hardware directly without using the BIOS. With this option, you can specify how Linux should detect the PCI devices. If you choose "BIOS", the BIOS will be used, if you choose "Direct", the BIOS won't be used, and if you choose "MMConfig", then PCI Express MMCONFIG will be used. If you choose "Any", the kernel will try MMCONFIG, then the direct access method and falls back to the BIOS if that doesn't work. If unsure, go with the default, which is "Any". config PCI_GOBIOS bool "BIOS" config PCI_GOMMCONFIG bool "MMConfig" config PCI_GODIRECT bool "Direct" config PCI_GOOLPC bool "OLPC XO-1" depends on OLPC config PCI_GOANY bool "Any" endchoice config PCI_BIOS def_bool y depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) # x86-64 doesn't support PCI BIOS access from long mode so always go direct. config PCI_DIRECT def_bool y depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC)) config PCI_MMCONFIG def_bool y depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY) config PCI_OLPC def_bool y depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) config PCI_XEN def_bool y depends on PCI && XEN select SWIOTLB_XEN config PCI_DOMAINS def_bool y depends on PCI config PCI_MMCONFIG bool "Support mmconfig PCI config space access" depends on X86_64 && PCI && ACPI config PCI_CNB20LE_QUIRK bool "Read CNB20LE Host Bridge Windows" if EXPERT default n depends on PCI && EXPERIMENTAL help Read the PCI windows out of the CNB20LE host bridge. This allows PCI hotplug to work on systems with the CNB20LE chipset which do not have ACPI. There's no public spec for this chipset, and this functionality is known to be incomplete. You should say N unless you know you need this. config DMAR bool "Support for DMA Remapping Devices (EXPERIMENTAL)" depends on PCI_MSI && ACPI && EXPERIMENTAL help DMA remapping (DMAR) devices support enables independent address translations for Direct Memory Access (DMA) from devices. These DMA remapping devices are reported via ACPI tables and include PCI device scope covered by these DMA remapping devices. config DMAR_DEFAULT_ON def_bool y prompt "Enable DMA Remapping Devices by default" depends on DMAR help Selecting this option will enable a DMAR device at boot time if one is found. If this option is not selected, DMAR support can be enabled by passing intel_iommu=on to the kernel. It is recommended you say N here while the DMAR code remains experimental. config DMAR_BROKEN_GFX_WA bool "Workaround broken graphics drivers (going away soon)" depends on DMAR && BROKEN ---help--- Current Graphics drivers tend to use physical address for DMA and avoid using DMA APIs. Setting this config option permits the IOMMU driver to set a unity map for all the OS-visible memory. Hence the driver can continue to use physical addresses for DMA, at least until this option is removed in the 2.6.32 kernel. config DMAR_FLOPPY_WA def_bool y depends on DMAR ---help--- Floppy disk drivers are known to bypass DMA API calls thereby failing to work when IOMMU is enabled. This workaround will setup a 1:1 mapping for the first 16MiB to make floppy (an ISA device) work. config INTR_REMAP bool "Support for Interrupt Remapping (EXPERIMENTAL)" depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL ---help--- Supports Interrupt remapping for IO-APIC and MSI devices. To use x2apic mode in the CPU's which support x2APIC enhancements or to support platforms with CPU's having > 8 bit APIC ID, say Y. source "drivers/pci/pcie/Kconfig" source "drivers/pci/Kconfig" # x86_64 have no ISA slots, but can have ISA-style DMA. config ISA_DMA_API bool "ISA-style DMA support" if (X86_64 && EXPERT) default y help Enables ISA-style DMA support for devices requiring such controllers. If unsure, say Y. if X86_32 config ISA bool "ISA support" ---help--- Find out whether you have ISA slots on your motherboard. ISA is the name of a bus system, i.e. the way the CPU talks to the other stuff inside your box. Other bus systems are PCI, EISA, MicroChannel (MCA) or VESA. ISA is an older system, now being displaced by PCI; newer boards don't support it. If you have ISA, say Y, otherwise N. config EISA bool "EISA support" depends on ISA ---help--- The Extended Industry Standard Architecture (EISA) bus was developed as an open alternative to the IBM MicroChannel bus. The EISA bus provided some of the features of the IBM MicroChannel bus while maintaining backward compatibility with cards made for the older ISA bus. The EISA bus saw limited use between 1988 and 1995 when it was made obsolete by the PCI bus. Say Y here if you are building a kernel for an EISA-based machine. Otherwise, say N. source "drivers/eisa/Kconfig" config MCA bool "MCA support" ---help--- MicroChannel Architecture is found in some IBM PS/2 machines and laptops. It is a bus system similar to PCI or ISA. See (and especially the web page given there) before attempting to build an MCA bus kernel. source "drivers/mca/Kconfig" config SCx200 tristate "NatSemi SCx200 support" ---help--- This provides basic support for National Semiconductor's (now AMD's) Geode processors. The driver probes for the PCI-IDs of several on-chip devices, so its a good dependency for other scx200_* drivers. If compiled as a module, the driver is named scx200. config SCx200HR_TIMER tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" depends on SCx200 default y ---help--- This driver provides a clocksource built upon the on-chip 27MHz high-resolution timer. Its also a workaround for NSC Geode SC-1100's buggy TSC, which loses time when the processor goes idle (as is done by the scheduler). The other workaround is idle=poll boot option. config OLPC bool "One Laptop Per Child support" depends on !X86_PAE select GPIOLIB select OF select OF_PROMTREE ---help--- Add support for detecting the unique features of the OLPC XO hardware. config OLPC_XO1 tristate "OLPC XO-1 support" depends on OLPC && MFD_CS5535 ---help--- Add support for non-essential features of the OLPC XO-1 laptop. endif # X86_32 config AMD_NB def_bool y depends on CPU_SUP_AMD && PCI source "drivers/pcmcia/Kconfig" source "drivers/pci/hotplug/Kconfig" config RAPIDIO bool "RapidIO support" depends on PCI default n help If you say Y here, the kernel will include drivers and infrastructure code to support RapidIO interconnect devices. source "drivers/rapidio/Kconfig" endmenu menu "Executable file formats / Emulations" source "fs/Kconfig.binfmt" config IA32_EMULATION bool "IA32 Emulation" depends on X86_64 select COMPAT_BINFMT_ELF ---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 tristate "IA32 a.out support" depends on IA32_EMULATION ---help--- Support old a.out binaries in the 32bit emulation. config COMPAT def_bool y depends on IA32_EMULATION config COMPAT_FOR_U64_ALIGNMENT def_bool COMPAT depends on X86_64 config SYSVIPC_COMPAT def_bool y depends on COMPAT && SYSVIPC config KEYS_COMPAT bool depends on COMPAT && KEYS default y endmenu config HAVE_ATOMIC_IOMAP def_bool y depends on X86_32 config HAVE_TEXT_POKE_SMP bool select STOP_MACHINE if SMP source "net/Kconfig" source "drivers/Kconfig" source "drivers/firmware/Kconfig" source "fs/Kconfig" source "arch/x86/Kconfig.debug" source "security/Kconfig" source "crypto/Kconfig" source "arch/x86/kvm/Kconfig" source "lib/Kconfig"