# # For a description of the syntax of this configuration file, # see Documentation/kbuild/kconfig-language.txt. # config MMU bool default y config RWSEM_GENERIC_SPINLOCK bool config RWSEM_XCHGADD_ALGORITHM bool default y config GENERIC_BUST_SPINLOCK bool mainmenu "Linux Kernel Configuration" config ARCH_S390 bool default y config UID16 bool default y depends on ARCH_S390X = 'n' source "init/Kconfig" menu "Base setup" comment "Processor type and features" config ARCH_S390X bool "64 bit kernel" help Select this option if you have a 64 bit IBM zSeries machine and want to use the 64 bit addressing mode. config 64BIT def_bool ARCH_S390X config ARCH_S390_31 bool depends on ARCH_S390X = 'n' default y choice prompt "Processor type" default MARCH_G5 config MARCH_G5 bool "S/390 model G5 and G6" depends on ARCH_S390_31 help Select this to build a 31 bit kernel that works on all S/390 and zSeries machines. config MARCH_Z900 bool "IBM eServer zSeries model z800 and z900" help Select this to optimize for zSeries machines. This will enable some optimizations that are not available on older 31 bit only CPUs. config MARCH_Z990 bool "IBM eServer zSeries model z990" help Select this enable optimizations for model z990. This will be slightly faster but does not work on older machines such as the z900. endchoice 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. See also the and the SMP-HOWTO available at . Even if you don't know what to do here, say Y. config NR_CPUS int "Maximum number of CPUs (2-64)" range 2 64 depends on SMP default "32" help This allows you to specify the maximum number of CPUs which this kernel will support. The maximum supported value is 64 and the minimum value which makes sense is 2. This is purely to save memory - each supported CPU adds approximately sixteen kilobytes to the kernel image. config MATHEMU bool "IEEE FPU emulation" depends on MARCH_G5 help This option is required for IEEE compliant floating point arithmetic on older S/390 machines. Say Y unless you know your machine doesn't need this. config S390_SUPPORT bool "Kernel support for 31 bit emulation" depends on ARCH_S390X help Select this option if you want to enable your system kernel to handle system-calls from ELF binaries for 31 bit ESA. This option (and some other stuff like libraries and such) is needed for executing 31 bit applications. It is safe to say "Y". config COMPAT bool depends on S390_SUPPORT default y config SYSVIPC_COMPAT bool depends on COMPAT && SYSVIPC default y config BINFMT_ELF32 tristate "Kernel support for 31 bit ELF binaries" depends on S390_SUPPORT help This allows you to run 32-bit Linux/ELF binaries on your zSeries in 64 bit mode. Everybody wants this; say Y. comment "I/O subsystem configuration" config MACHCHK_WARNING bool "Process warning machine checks" help Select this option if you want the machine check handler on IBM S/390 or zSeries to process warning machine checks (e.g. on power failures). If unsure, say "Y". config QDIO tristate "QDIO support" ---help--- This driver provides the Queued Direct I/O base support for the IBM S/390 (G5 and G6) and eServer zSeries (z800, z900 and z990). For details please refer to the documentation provided by IBM at To compile this driver as a module, choose M here: the module will be called qdio. If unsure, say Y. config QDIO_PERF_STATS bool "Performance statistics in /proc" depends on QDIO help Say Y here to get performance statistics in /proc/qdio_perf If unsure, say N. comment "Misc" config PREEMPT bool "Preemptible Kernel" help This option reduces the latency of the kernel when reacting to real-time or interactive events by allowing a low priority process to be preempted even if it is in kernel mode executing a system call. This allows applications to run more reliably even when the system is under load. Say N if you are unsure. config IPL bool "Builtin IPL record support" help If you want to use the produced kernel to IPL directly from a device, you have to merge a bootsector specific to the device into the first bytes of the kernel. You will have to select the IPL device. choice prompt "IPL method generated into head.S" depends on IPL default IPL_TAPE help Select "tape" if you want to IPL the image from a Tape. Select "vm_reader" if you are running under VM/ESA and want to IPL the image from the emulated card reader. config IPL_TAPE bool "tape" config IPL_VM bool "vm_reader" endchoice source "fs/Kconfig.binfmt" config PROCESS_DEBUG bool "Show crashed user process info" help Say Y to print all process fault locations to the console. This is a debugging option; you probably do not want to set it unless you are an S390 port maintainer. config PFAULT bool "Pseudo page fault support" help Select this option, if you want to use PFAULT pseudo page fault handling under VM. If running native or in LPAR, this option has no effect. If your VM does not support PFAULT, PAGEEX pseudo page fault handling will be used. Note that VM 4.2 supports PFAULT but has a bug in its implementation that causes some problems. Everybody who wants to run Linux under VM != VM4.2 should select this option. config SHARED_KERNEL bool "VM shared kernel support" help Select this option, if you want to share the text segment of the Linux kernel between different VM guests. This reduces memory usage with lots of guests but greatly increases kernel size. You should only select this option if you know what you are doing and want to exploit this feature. config CMM tristate "Cooperative memory management" help Select this option, if you want to enable the kernel interface to reduce the memory size of the system. This is accomplished by allocating pages of memory and put them "on hold". This only makes sense for a system running under VM where the unused pages will be reused by VM for other guest systems. The interface allows an external monitor to balance memory of many systems. Everybody who wants to run Linux under VM should select this option. config CMM_PROC bool "/proc interface to cooperative memory management" depends on CMM help Select this option to enable the /proc interface to the cooperative memory management. config CMM_IUCV bool "IUCV special message interface to cooperative memory management" depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) help Select this option to enable the special message interface to the cooperative memory management. config VIRT_TIMER bool "Virtual CPU timer support" help This provides a kernel interface for virtual CPU timers. Default is disabled. config APPLDATA_BASE bool "Linux - VM Monitor Stream, base infrastructure" depends on PROC_FS && VIRT_TIMER=y help This provides a kernel interface for creating and updating z/VM APPLDATA monitor records. The monitor records are updated at certain time intervals, once the timer is started. Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, i.e. enables or disables monitoring on the Linux side. A custom interval value (in seconds) can be written to /proc/appldata/interval. Defaults are 60 seconds interval and timer off. The /proc entries can also be read from, showing the current settings. config APPLDATA_MEM tristate "Monitor memory management statistics" depends on APPLDATA_BASE help This provides memory management related data to the Linux - VM Monitor Stream, like paging/swapping rate, memory utilisation, etc. Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM APPLDATA monitor record, i.e. enables or disables monitoring this record on the z/VM side. Default is disabled. The /proc entry can also be read from, showing the current settings. This can also be compiled as a module, which will be called appldata_mem.o. config APPLDATA_OS tristate "Monitor OS statistics" depends on APPLDATA_BASE help This provides OS related data to the Linux - VM Monitor Stream, like CPU utilisation, etc. Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM APPLDATA monitor record, i.e. enables or disables monitoring this record on the z/VM side. Default is disabled. This can also be compiled as a module, which will be called appldata_os.o. config APPLDATA_NET_SUM tristate "Monitor overall network statistics" depends on APPLDATA_BASE help This provides network related data to the Linux - VM Monitor Stream, currently there is only a total sum of network I/O statistics, no per-interface data. Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM APPLDATA monitor record, i.e. enables or disables monitoring this record on the z/VM side. Default is disabled. This can also be compiled as a module, which will be called appldata_net_sum.o. config NO_IDLE_HZ bool "No HZ timer ticks in idle" help Switches the regular HZ timer off when the system is going idle. This helps z/VM to detect that the Linux system is idle. VM can then "swap-out" this guest which reduces memory usage. It also reduces the overhead of idle systems. The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer. hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ timer is active. config NO_IDLE_HZ_INIT bool "HZ timer in idle off by default" depends on NO_IDLE_HZ help The HZ timer is switched off in idle by default. That means the HZ timer is already disabled at boot time. endmenu config PCMCIA bool default n source "drivers/base/Kconfig" source "drivers/scsi/Kconfig" source "drivers/s390/Kconfig" source "net/Kconfig" source "fs/Kconfig" source "arch/s390/oprofile/Kconfig" menu "Kernel hacking" config DEBUG_KERNEL bool "Kernel debugging" help Say Y here if you are developing drivers or trying to debug and identify kernel problems. config MAGIC_SYSRQ bool "Magic SysRq key" depends on DEBUG_KERNEL help If you say Y here, you will have some control over the system even if the system crashes for example during kernel debugging (e.g., you will be able to flush the buffer cache to disk, reboot the system immediately or dump some status information). This is accomplished by pressing various keys while holding SysRq (Alt+PrintScreen). It also works on a serial console (on PC hardware at least), if you send a BREAK and then within 5 seconds a command keypress. The keys are documented in . Don't say Y unless you really know what this hack does. config DEBUG_SLAB bool "Debug memory allocations" depends on DEBUG_KERNEL help Say Y here to have the kernel do limited verification on memory allocation as well as poisoning memory on free to catch use of freed memory. config KALLSYMS bool "Load all symbols for debugging/kksymoops" depends on DEBUG_KERNEL help Say Y here to let the kernel print out symbolic crash information and symbolic stack backtraces. This increases the size of the kernel somewhat, as all symbols have to be loaded into the kernel image. config DEBUG_INFO bool "Compile the kernel with debug info" depends on DEBUG_KERNEL help If you say Y here the resulting kernel image will include debugging info resulting in a larger kernel image. Say Y here only if you plan to use gdb to debug the kernel. If you don't debug the kernel, you can say N. config DEBUG_SPINLOCK_SLEEP bool "Sleep-inside-spinlock checking" help If you say Y here, various routines which may sleep will become very noisy if they are called with a spinlock held. endmenu source "security/Kconfig" source "crypto/Kconfig" source "lib/Kconfig"