# # For a description of the syntax of this configuration file, # see Documentation/kbuild/kconfig-language.txt. # mainmenu "Linux Kernel Configuration" config X86_32 bool default y help This is Linux's home port. Linux was originally native to the Intel 386, and runs on all the later x86 processors including the Intel 486, 586, Pentiums, and various instruction-set-compatible chips by AMD, Cyrix, and others. config GENERIC_TIME bool default y config GENERIC_CMOS_UPDATE bool default y config CLOCKSOURCE_WATCHDOG bool default y config GENERIC_CLOCKEVENTS bool default y config GENERIC_CLOCKEVENTS_BROADCAST bool default y depends on X86_LOCAL_APIC config LOCKDEP_SUPPORT bool default y config STACKTRACE_SUPPORT bool default y config SEMAPHORE_SLEEPERS bool default y config X86 bool default y config MMU bool default y config ZONE_DMA bool default y config QUICKLIST bool default y config SBUS bool config GENERIC_ISA_DMA bool default y config GENERIC_IOMAP bool default y config GENERIC_BUG bool default y depends on BUG config GENERIC_HWEIGHT bool default y config ARCH_MAY_HAVE_PC_FDC bool default y config DMI bool default y 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" 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)" 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 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 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 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)" 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)" 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 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. endchoice config SCHED_NO_NO_OMIT_FRAME_POINTER bool "Single-depth WCHAN output" default y 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_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" 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 bool default y depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH) select ACPI_NUMA config HAVE_ARCH_PARSE_SRAT bool default y depends on ACPI_SRAT config X86_SUMMIT_NUMA bool default y depends on NUMA && (X86_SUMMIT || X86_GENERICARCH) config X86_CYCLONE_TIMER bool default y depends on X86_SUMMIT || X86_GENERICARCH config ES7000_CLUSTERED_APIC bool default y depends on SMP && X86_ES7000 && MPENTIUMIII source "arch/x86/Kconfig.cpu" config HPET_TIMER bool "HPET Timer Support" help This enables the use of the HPET for the kernel's internal timer. HPET is the next generation timer replacing legacy 8254s. 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 bool depends on HPET_TIMER && RTC=y default 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_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 bool "Multi-core scheduler support" depends on X86_HT default y 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 !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 bool depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH default y config X86_IO_APIC bool depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH default y config X86_VISWS_APIC bool depends on X86_VISWS default y 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_NONFATAL tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4" depends on 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_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 default y bool "Enable VM86 support" if EMBEDDED 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" ---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" ---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 default n ---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 bool depends on MICROCODE default y 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. source "drivers/firmware/Kconfig" choice prompt "High Memory Support" default HIGHMEM4G if !X86_NUMAQ default HIGHMEM64G if X86_NUMAQ 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 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 config HIGHMEM bool depends on HIGHMEM64G || HIGHMEM4G default y config X86_PAE bool "PAE (Physical Address Extension) Support" default n depends on !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 && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL default n if X86_PC default y if (X86_NUMAQ || X86_SUMMIT) help NUMA support for i386. This is currently highly experimental and should be only used for kernel development. It might also cause boot failures. comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI" depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI) config NODES_SHIFT int default "4" if X86_NUMAQ default "3" depends on NEED_MULTIPLE_NODES config HAVE_ARCH_BOOTMEM_NODE bool depends on NUMA default y config ARCH_HAVE_MEMORY_PRESENT bool depends on DISCONTIGMEM default y config NEED_NODE_MEMMAP_SIZE bool depends on DISCONTIGMEM || SPARSEMEM default y config HAVE_ARCH_ALLOC_REMAP bool depends on NUMA default y config ARCH_FLATMEM_ENABLE def_bool y depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC) config ARCH_DISCONTIGMEM_ENABLE def_bool y depends on NUMA config ARCH_DISCONTIGMEM_DEFAULT def_bool y depends on NUMA config ARCH_SPARSEMEM_ENABLE def_bool y depends on (NUMA || (X86_PC && EXPERIMENTAL)) select SPARSEMEM_STATIC config ARCH_SELECT_MEMORY_MODEL def_bool y depends on ARCH_SPARSEMEM_ENABLE config ARCH_POPULATES_NODE_MAP def_bool y source "mm/Kconfig" config HIGHPTE bool "Allocate 3rd-level pagetables from highmem" depends on 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 "Math emulation" ---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 bool "Boot from EFI support" depends on ACPI default n ---help--- This enables the kernel to boot on EFI platforms using system configuration information passed to it from the firmware. This also enables the kernel to use any EFI runtime services that are available (such as the EFI variable services). This option is only useful on systems that have EFI firmware and will result in a kernel image that is ~8k larger. In addition, you must use the latest ELILO loader available at in order to take advantage of kernel initialization using EFI information (neither GRUB nor LILO know anything about EFI). However, even with this option, the resultant kernel should continue to boot on existing non-EFI platforms. config IRQBALANCE bool "Enable kernel irq balancing" depends on SMP && X86_IO_APIC default y 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 bool depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI)) default y config SECCOMP bool "Enable seccomp to safely compute untrusted bytecode" depends on PROC_FS default y 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. 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 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 "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. config PHYSICAL_ALIGN hex "Alignment value to which kernel should be aligned" default "0x100000" 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. config COMPAT_VDSO bool "Compat VDSO support" default y help Map the 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 HIGHMEM menu "Power management options (ACPI, APM)" depends on !X86_VOYAGER source kernel/power/Kconfig source "drivers/acpi/Kconfig" menuconfig APM tristate "APM (Advanced Power Management) BIOS support" depends on 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, PCMCIA, EISA, MCA, ISA)" config PCI bool "PCI support" if !X86_VISWS depends on !X86_VOYAGER default y if X86_VISWS 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 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 bool depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY) default y config PCI_DIRECT bool depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS) default y config PCI_MMCONFIG bool depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY) default y config PCI_DOMAINS bool depends on PCI default y source "drivers/pci/pcie/Kconfig" source "drivers/pci/Kconfig" config ISA_DMA_API bool default y 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 bool "Geode Multi-Function General Purpose Timer (MFGPT) events" depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS default y 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. config K8_NB def_bool y depends on AGP_AMD64 source "drivers/pcmcia/Kconfig" source "drivers/pci/hotplug/Kconfig" endmenu menu "Executable file formats" source "fs/Kconfig.binfmt" endmenu source "net/Kconfig" source "drivers/Kconfig" source "fs/Kconfig" source "kernel/Kconfig.instrumentation" source "arch/x86/Kconfig.debug" source "security/Kconfig" source "crypto/Kconfig" source "lib/Kconfig" # # 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_VOYAGER default y config X86_HT bool depends on SMP && !(X86_VISWS || X86_VOYAGER) default y config X86_BIOS_REBOOT bool depends on !(X86_VISWS || X86_VOYAGER) default y config X86_TRAMPOLINE bool depends on X86_SMP || (X86_VOYAGER && SMP) default y config KTIME_SCALAR bool default y