# x86 configuration mainmenu "Linux Kernel Configuration for x86" # 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 config X86_64 def_bool 64BIT ### Arch settings config X86 def_bool y config GENERIC_LOCKBREAK def_bool n config GENERIC_TIME def_bool y 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 SEMAPHORE_SLEEPERS def_bool y config MMU def_bool y config ZONE_DMA def_bool y config QUICKLIST def_bool X86_32 config SBUS bool config GENERIC_ISA_DMA def_bool y config GENERIC_IOMAP def_bool y config GENERIC_BUG def_bool y depends on BUG config GENERIC_HWEIGHT def_bool y config ARCH_MAY_HAVE_PC_FDC def_bool y config DMI def_bool y config RWSEM_GENERIC_SPINLOCK def_bool !X86_XADD config RWSEM_XCHGADD_ALGORITHM def_bool X86_XADD config ARCH_HAS_ILOG2_U32 def_bool n config ARCH_HAS_ILOG2_U64 def_bool n config GENERIC_CALIBRATE_DELAY def_bool y config GENERIC_TIME_VSYSCALL bool default X86_64 config ARCH_SETS_UP_PER_CPU_AREA def_bool X86_64 config ARCH_SUPPORTS_OPROFILE bool default y config ZONE_DMA32 bool default X86_64 config ARCH_POPULATES_NODE_MAP def_bool y config AUDIT_ARCH bool default X86_64 # Use the generic interrupt handling code in kernel/irq/: config GENERIC_HARDIRQS bool default y config GENERIC_IRQ_PROBE bool default y config GENERIC_PENDING_IRQ bool depends on GENERIC_HARDIRQS && SMP default y config X86_SMP bool depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64) default y 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 bool depends on SMP depends on (X86_32 && !(X86_VISWS || X86_VOYAGER)) || (X86_64 && !MK8) default y config X86_BIOS_REBOOT bool depends on X86_32 && !(X86_VISWS || X86_VOYAGER) default y config X86_TRAMPOLINE bool depends on X86_SMP || (X86_VOYAGER && SMP) default y config KTIME_SCALAR def_bool X86_32 source "init/Kconfig" 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 the , , and the SMP-HOWTO available at . If you don't know what to do here, say N. choice prompt "Subarchitecture Type" default X86_PC config X86_PC bool "PC-compatible" help Choose this option if your computer is a standard PC or compatible. config X86_ELAN bool "AMD Elan" depends on X86_32 help Select this for an AMD Elan processor. Do not use this option for K6/Athlon/Opteron processors! If unsure, choose "PC-compatible" instead. config X86_VOYAGER bool "Voyager (NCR)" depends on X86_32 select SMP if !BROKEN help Voyager is an MCA-based 32-way capable SMP architecture proprietary to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based. *** WARNING *** If you do not specifically know you have a Voyager based machine, say N here, otherwise the kernel you build will not be bootable. config X86_NUMAQ bool "NUMAQ (IBM/Sequent)" select SMP select NUMA depends on X86_32 help This option is used for getting Linux to run on a (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_SUMMIT bool "Summit/EXA (IBM x440)" depends on X86_32 && SMP help This option is needed for IBM systems that use the Summit/EXA chipset. In particular, it is needed for the x440. If you don't have one of these computers, you should say N here. If you want to build a NUMA kernel, you must select ACPI. config X86_BIGSMP bool "Support for other sub-arch 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 and if the system is not of any sub-arch type above. If you don't have such a system, you should say N here. config X86_VISWS bool "SGI 320/540 (Visual Workstation)" depends on X86_32 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 not run on PCs and vice versa. See for details. config X86_GENERICARCH bool "Generic architecture (Summit, bigsmp, ES7000, default)" depends on X86_32 help This option compiles in the Summit, bigsmp, ES7000, default subarchitectures. It is intended for a generic binary kernel. If you want a NUMA kernel, select ACPI. We need SRAT for NUMA. config X86_ES7000 bool "Support for Unisys ES7000 IA32 series" depends on X86_32 && SMP help Support for Unisys ES7000 systems. Say 'Y' here if this kernel is supposed to run on an IA32-based Unisys ES7000 system. Only choose this option if you have such a system, otherwise you should say N here. config X86_VSMP bool "Support for ScaleMP vSMP" depends on X86_64 && PCI 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. endchoice config SCHED_NO_NO_OMIT_FRAME_POINTER def_bool y prompt "Single-depth WCHAN output" depends on X86_32 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". config PARAVIRT bool depends on X86_32 && !(X86_VISWS || X86_VOYAGER) 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. menuconfig PARAVIRT_GUEST bool "Paravirtualized guest support" depends on X86_32 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 VMI bool "VMI Guest support" select PARAVIRT depends on !(X86_VISWS || X86_VOYAGER) help VMI provides a paravirtualized interface to the VMware ESX server (it could be used by other hypervisors in theory too, but is not at the moment), by linking the kernel to a GPL-ed ROM module provided by the hypervisor. source "arch/x86/lguest/Kconfig" endif config ACPI_SRAT def_bool y depends on X86_32 && ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH) select ACPI_NUMA config HAVE_ARCH_PARSE_SRAT def_bool y depends on ACPI_SRAT config X86_SUMMIT_NUMA def_bool y depends on X86_32 && NUMA && (X86_SUMMIT || X86_GENERICARCH) config X86_CYCLONE_TIMER def_bool y depends on X86_32 && X86_SUMMIT || X86_GENERICARCH config ES7000_CLUSTERED_APIC def_bool y depends on SMP && X86_ES7000 && MPENTIUMIII 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 # Mark as embedded because too many people got it wrong. # The code disables itself when not needed. config GART_IOMMU bool "GART IOMMU support" if EMBEDDED default y select SWIOTLB select AGP depends on X86_64 && PCI 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. # need this always selected by IOMMU for the VIA workaround config SWIOTLB bool 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 NR_CPUS int "Maximum number of CPUs (2-255)" range 2 255 depends on SMP default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000 default "8" help This allows you to specify the maximum number of CPUs which this kernel will support. The maximum supported value is 255 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_64 && SMP) || (X86_32 && 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_64 && SMP) || (X86_32 && 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. source "kernel/Kconfig.preempt" config X86_UP_APIC bool "Local APIC support on uniprocessors" depends on X86_32 && !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH) 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 || (X86_32 && (X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH)) config X86_IO_APIC def_bool y depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH)) config X86_VISWS_APIC def_bool y depends on X86_32 && X86_VISWS config X86_MCE bool "Machine Check Exception" depends on !X86_VOYAGER ---help--- Machine Check Exception support allows the processor to notify the kernel if it detects a problem (e.g. overheating, component failure). The action the kernel takes depends on the severity of the problem, ranging from a warning message on the console, to halting the machine. Your processor must be a Pentium or newer to support this - check the flags in /proc/cpuinfo for mce. Note that some older Pentium systems have a design flaw which leads to false MCE events - hence MCE is disabled on all P5 processors, unless explicitly enabled with "mce" as a boot argument. Similarly, if MCE is built in and creates a problem on some new non-standard machine, you can boot with "nomce" to disable it. MCE support simply ignores non-MCE processors like the 386 and 486, so nearly everyone can say Y here. config X86_MCE_INTEL def_bool y prompt "Intel MCE features" depends on X86_64 && 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_64 && X86_MCE && X86_LOCAL_APIC help Additional support for AMD specific MCE features such as the DRAM Error Threshold. config X86_MCE_NONFATAL tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4" depends on X86_32 && X86_MCE help Enabling this feature starts a timer that triggers every 5 seconds which will look at the machine check registers to see if anything happened. Non-fatal problems automatically get corrected (but still logged). Disable this if you don't want to see these messages. Seeing the messages this option prints out may be indicative of dying or out-of-spec (ie, overclocked) hardware. This option only does something on certain CPUs. (AMD Athlon/Duron and Intel Pentium 4) config X86_MCE_P4THERMAL bool "check for P4 thermal throttling interrupt." depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS help Enabling this feature will cause a message to be printed when the P4 enters thermal throttling. config VM86 bool "Enable VM86 support" if EMBEDDED 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" depends on X86_32 ---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 def_bool n prompt "Enable X86 board specific fixups for reboot" depends on X86_32 && X86 ---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. 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 - Intel IA32 CPU microcode support" select FW_LOADER ---help--- If you say Y here, you will be able to update the microcode on Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. 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. 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 HIGHMEM4G if !X86_NUMAQ default HIGHMEM64G if X86_NUMAQ 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 EMBEDDED 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 def_bool n prompt "PAE (Physical Address Extension) Support" depends on X86_32 && !HIGHMEM4G select RESOURCES_64BIT 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. # Common NUMA Features config NUMA bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)" depends on SMP depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL) default n if X86_PC default y if (X86_NUMAQ || X86_SUMMIT) 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 i386 this is currently highly experimental and should be only used for kernel development. It might also cause boot failures. For x86_64 this is recommended on all multiprocessor Opteron systems. If the system is EM64T, you should say N unless your system is EM64T NUMA. comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI" depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI) config K8_NUMA def_bool y prompt "Old style AMD Opteron NUMA detection" depends on X86_64 && NUMA && PCI help Enable K8 NUMA node topology detection. You should say Y here if you have a multi processor AMD K8 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. config NUMA_EMU bool "NUMA emulation" depends on X86_64 && 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 range 1 15 if X86_64 default "6" if X86_64 default "4" if X86_NUMAQ default "3" depends on NEED_MULTIPLE_NODES config HAVE_ARCH_BOOTMEM_NODE 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 HAVE_ARCH_ALLOC_REMAP def_bool y depends on X86_32 && NUMA config ARCH_FLATMEM_ENABLE def_bool y depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && X86_PC && !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_DEFAULT def_bool y depends on X86_64 config ARCH_SPARSEMEM_ENABLE def_bool y depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) select SPARSEMEM_STATIC if X86_32 select SPARSEMEM_VMEMMAP_ENABLE if 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 source "mm/Kconfig" config HIGHPTE bool "Allocate 3rd-level pagetables from highmem" depends on X86_32 && (HIGHMEM4G || HIGHMEM64G) 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 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 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: 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 EFI def_bool n prompt "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 IRQBALANCE def_bool y prompt "Enable kernel irq balancing" depends on X86_32 && SMP && X86_IO_APIC help The default yes will allow the kernel to do irq load balancing. Saying no will keep the kernel from doing irq load balancing. # turning this on wastes a bunch of space. # Summit needs it only when NUMA is on config BOOT_IOREMAP def_bool y depends on X86_32 && (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI)) config SECCOMP def_bool y prompt "Enable seccomp to safely compute untrusted bytecode" depends on PROC_FS 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 /proc//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)" depends on X86_64 && EXPERIMENTAL help This option turns on the -fstack-protector GCC feature. This feature puts, at the beginning of critical 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. config CC_STACKPROTECTOR_ALL bool "Use stack-protector for all functions" depends on CC_STACKPROTECTOR help Normally, GCC only inserts the canary value protection for functions that use large-ish on-stack buffers. By enabling this option, GCC will be asked to do this for ALL functions. 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 (EXPERIMENTAL)" depends on EXPERIMENTAL 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 PHYSICAL_START hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP) default "0x1000000" if X86_NUMAQ default "0x200000" if X86_64 default "0x100000" 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 0x100000 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 (Typically 16MB 0x1000000). 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. Typically this parameter is set as crashkernel=64M@16M. 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 (EXPERIMENTAL)" depends on EXPERIMENTAL 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. config PHYSICAL_ALIGN hex prompt "Alignment value to which kernel should be aligned" if X86_32 default "0x100000" if X86_32 default "0x200000" if X86_64 range 0x2000 0x400000 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 suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)" depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER ---help--- Say Y here to experiment with turning CPUs off and on, and to enable suspend on SMP systems. CPUs can be controlled through /sys/devices/system/cpu. Say N if you want to disable CPU hotplug and don't need to suspend. 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. ---help--- 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. endmenu config ARCH_ENABLE_MEMORY_HOTPLUG def_bool y depends on X86_64 || (X86_32 && HIGHMEM) config HAVE_ARCH_EARLY_PFN_TO_NID def_bool X86_64 depends on NUMA menu "Power management options" depends on !X86_VOYAGER config ARCH_HIBERNATION_HEADER def_bool y depends on X86_64 && HIBERNATION source "kernel/power/Kconfig" source "drivers/acpi/Kconfig" config X86_APM_BOOT bool default y depends on APM || APM_MODULE menuconfig APM tristate "APM (Advanced Power Management) BIOS support" depends on X86_32 && PM_SLEEP && !X86_VISWS ---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. config APM_REAL_MODE_POWER_OFF bool "Use real mode APM BIOS call to power off" help Use real mode APM BIOS calls to switch off the computer. This is a work-around for a number of buggy BIOSes. Switch this option on if your computer crashes instead of powering off properly. endif # APM source "arch/x86/kernel/cpu/cpufreq/Kconfig" source "drivers/cpuidle/Kconfig" endmenu menu "Bus options (PCI etc.)" config PCI bool "PCI support" if !X86_VISWS depends on !X86_VOYAGER 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. The PCI-HOWTO, available from , contains valuable information about which PCI hardware does work under Linux and which doesn't. choice prompt "PCI access mode" depends on X86_32 && PCI && !X86_VISWS 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_GOANY bool "Any" endchoice config PCI_BIOS def_bool y depends on X86_32 && !X86_VISWS && 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) || X86_VISWS) config PCI_MMCONFIG def_bool y depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY) 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 DMAR bool "Support for DMA Remapping Devices (EXPERIMENTAL)" depends on X86_64 && 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_GFX_WA def_bool y prompt "Support for Graphics workaround" depends on DMAR 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. config DMAR_FLOPPY_WA def_bool y depends on DMAR help Floppy disk drivers are know to bypass DMA API calls thereby failing to work when IOMMU is enabled. This workaround will setup a 1:1 mapping for the first 16M to make floppy (an ISA device) work. source "drivers/pci/pcie/Kconfig" source "drivers/pci/Kconfig" # x86_64 have no ISA slots, but do have ISA-style DMA. config ISA_DMA_API def_bool y if X86_32 config ISA bool "ISA support" depends on !(X86_VOYAGER || X86_VISWS) 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" if !(X86_VISWS || X86_VOYAGER) default y if X86_VOYAGER 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" depends on !X86_VOYAGER 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 && GENERIC_TIME 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 GEODE_MFGPT_TIMER def_bool y prompt "Geode Multi-Function General Purpose Timer (MFGPT) events" depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS help This driver provides a clock event source based on the MFGPT timer(s) in the CS5535 and CS5536 companion chip for the geode. MFGPTs have a better resolution and max interval than the generic PIT, and are suitable for use as high-res timers. endif # X86_32 config K8_NB def_bool y depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA))) 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" 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 X86_64 && COMPAT && SYSVIPC endmenu source "net/Kconfig" source "drivers/Kconfig" source "drivers/firmware/Kconfig" source "fs/Kconfig" source "kernel/Kconfig.instrumentation" source "arch/x86/Kconfig.debug" source "security/Kconfig" source "crypto/Kconfig" source "lib/Kconfig"