7 option env="KERNELVERSION"
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
16 default "$ARCH_DEFCONFIG"
17 default "arch/$ARCH/defconfig"
26 config BUILDTIME_EXTABLE_SORT
36 depends on BROKEN || !SMP
39 config INIT_ENV_ARG_LIMIT
44 Maximum of each of the number of arguments and environment
45 variables passed to init from the kernel command line.
49 string "Cross-compiler tool prefix"
51 Same as running 'make CROSS_COMPILE=prefix-' but stored for
52 default make runs in this kernel build directory. You don't
53 need to set this unless you want the configured kernel build
54 directory to select the cross-compiler automatically.
57 bool "Compile also drivers which will not load"
60 Some drivers can be compiled on a different platform than they are
61 intended to be run on. Despite they cannot be loaded there (or even
62 when they load they cannot be used due to missing HW support),
63 developers still, opposing to distributors, might want to build such
64 drivers to compile-test them.
66 If you are a developer and want to build everything available, say Y
67 here. If you are a user/distributor, say N here to exclude useless
68 drivers to be distributed.
71 string "Local version - append to kernel release"
73 Append an extra string to the end of your kernel version.
74 This will show up when you type uname, for example.
75 The string you set here will be appended after the contents of
76 any files with a filename matching localversion* in your
77 object and source tree, in that order. Your total string can
78 be a maximum of 64 characters.
80 config LOCALVERSION_AUTO
81 bool "Automatically append version information to the version string"
84 This will try to automatically determine if the current tree is a
85 release tree by looking for git tags that belong to the current
88 A string of the format -gxxxxxxxx will be added to the localversion
89 if a git-based tree is found. The string generated by this will be
90 appended after any matching localversion* files, and after the value
91 set in CONFIG_LOCALVERSION.
93 (The actual string used here is the first eight characters produced
94 by running the command:
96 $ git rev-parse --verify HEAD
98 which is done within the script "scripts/setlocalversion".)
100 config HAVE_KERNEL_GZIP
103 config HAVE_KERNEL_BZIP2
106 config HAVE_KERNEL_LZMA
109 config HAVE_KERNEL_XZ
112 config HAVE_KERNEL_LZO
115 config HAVE_KERNEL_LZ4
119 prompt "Kernel compression mode"
121 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
123 The linux kernel is a kind of self-extracting executable.
124 Several compression algorithms are available, which differ
125 in efficiency, compression and decompression speed.
126 Compression speed is only relevant when building a kernel.
127 Decompression speed is relevant at each boot.
129 If you have any problems with bzip2 or lzma compressed
130 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
131 version of this functionality (bzip2 only), for 2.4, was
132 supplied by Christian Ludwig)
134 High compression options are mostly useful for users, who
135 are low on disk space (embedded systems), but for whom ram
138 If in doubt, select 'gzip'
142 depends on HAVE_KERNEL_GZIP
144 The old and tried gzip compression. It provides a good balance
145 between compression ratio and decompression speed.
149 depends on HAVE_KERNEL_BZIP2
151 Its compression ratio and speed is intermediate.
152 Decompression speed is slowest among the choices. The kernel
153 size is about 10% smaller with bzip2, in comparison to gzip.
154 Bzip2 uses a large amount of memory. For modern kernels you
155 will need at least 8MB RAM or more for booting.
159 depends on HAVE_KERNEL_LZMA
161 This compression algorithm's ratio is best. Decompression speed
162 is between gzip and bzip2. Compression is slowest.
163 The kernel size is about 33% smaller with LZMA in comparison to gzip.
167 depends on HAVE_KERNEL_XZ
169 XZ uses the LZMA2 algorithm and instruction set specific
170 BCJ filters which can improve compression ratio of executable
171 code. The size of the kernel is about 30% smaller with XZ in
172 comparison to gzip. On architectures for which there is a BCJ
173 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
174 will create a few percent smaller kernel than plain LZMA.
176 The speed is about the same as with LZMA: The decompression
177 speed of XZ is better than that of bzip2 but worse than gzip
178 and LZO. Compression is slow.
182 depends on HAVE_KERNEL_LZO
184 Its compression ratio is the poorest among the choices. The kernel
185 size is about 10% bigger than gzip; however its speed
186 (both compression and decompression) is the fastest.
190 depends on HAVE_KERNEL_LZ4
192 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
193 A preliminary version of LZ4 de/compression tool is available at
194 <https://code.google.com/p/lz4/>.
196 Its compression ratio is worse than LZO. The size of the kernel
197 is about 8% bigger than LZO. But the decompression speed is
202 config DEFAULT_HOSTNAME
203 string "Default hostname"
206 This option determines the default system hostname before userspace
207 calls sethostname(2). The kernel traditionally uses "(none)" here,
208 but you may wish to use a different default here to make a minimal
209 system more usable with less configuration.
212 bool "Support for paging of anonymous memory (swap)"
213 depends on MMU && BLOCK
216 This option allows you to choose whether you want to have support
217 for so called swap devices or swap files in your kernel that are
218 used to provide more virtual memory than the actual RAM present
219 in your computer. If unsure say Y.
224 Inter Process Communication is a suite of library functions and
225 system calls which let processes (running programs) synchronize and
226 exchange information. It is generally considered to be a good thing,
227 and some programs won't run unless you say Y here. In particular, if
228 you want to run the DOS emulator dosemu under Linux (read the
229 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
230 you'll need to say Y here.
232 You can find documentation about IPC with "info ipc" and also in
233 section 6.4 of the Linux Programmer's Guide, available from
234 <http://www.tldp.org/guides.html>.
236 config SYSVIPC_SYSCTL
243 bool "POSIX Message Queues"
246 POSIX variant of message queues is a part of IPC. In POSIX message
247 queues every message has a priority which decides about succession
248 of receiving it by a process. If you want to compile and run
249 programs written e.g. for Solaris with use of its POSIX message
250 queues (functions mq_*) say Y here.
252 POSIX message queues are visible as a filesystem called 'mqueue'
253 and can be mounted somewhere if you want to do filesystem
254 operations on message queues.
258 config POSIX_MQUEUE_SYSCTL
260 depends on POSIX_MQUEUE
265 bool "open by fhandle syscalls"
268 If you say Y here, a user level program will be able to map
269 file names to handle and then later use the handle for
270 different file system operations. This is useful in implementing
271 userspace file servers, which now track files using handles instead
272 of names. The handle would remain the same even if file names
273 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
277 bool "Auditing support"
280 Enable auditing infrastructure that can be used with another
281 kernel subsystem, such as SELinux (which requires this for
282 logging of avc messages output). Does not do system-call
283 auditing without CONFIG_AUDITSYSCALL.
286 bool "Enable system-call auditing support"
287 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
288 default y if SECURITY_SELINUX
290 Enable low-overhead system-call auditing infrastructure that
291 can be used independently or with another kernel subsystem,
296 depends on AUDITSYSCALL
301 depends on AUDITSYSCALL
304 config AUDIT_LOGINUID_IMMUTABLE
305 bool "Make audit loginuid immutable"
308 The config option toggles if a task setting its loginuid requires
309 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
310 but should instead only allow setting its loginuid if it was never
311 previously set. On systems which use systemd or a similar central
312 process to restart login services this should be set to true. On older
313 systems in which an admin would typically have to directly stop and
314 start processes this should be set to false. Setting this to true allows
315 one to drop potentially dangerous capabilites from the login tasks,
316 but may not be backwards compatible with older init systems.
318 source "kernel/irq/Kconfig"
319 source "kernel/time/Kconfig"
321 menu "CPU/Task time and stats accounting"
323 config VIRT_CPU_ACCOUNTING
327 prompt "Cputime accounting"
328 default TICK_CPU_ACCOUNTING if !PPC64
329 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
331 # Kind of a stub config for the pure tick based cputime accounting
332 config TICK_CPU_ACCOUNTING
333 bool "Simple tick based cputime accounting"
334 depends on !S390 && !NO_HZ_FULL
336 This is the basic tick based cputime accounting that maintains
337 statistics about user, system and idle time spent on per jiffies
342 config VIRT_CPU_ACCOUNTING_NATIVE
343 bool "Deterministic task and CPU time accounting"
344 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
345 select VIRT_CPU_ACCOUNTING
347 Select this option to enable more accurate task and CPU time
348 accounting. This is done by reading a CPU counter on each
349 kernel entry and exit and on transitions within the kernel
350 between system, softirq and hardirq state, so there is a
351 small performance impact. In the case of s390 or IBM POWER > 5,
352 this also enables accounting of stolen time on logically-partitioned
355 config VIRT_CPU_ACCOUNTING_GEN
356 bool "Full dynticks CPU time accounting"
357 depends on HAVE_CONTEXT_TRACKING && 64BIT
358 select VIRT_CPU_ACCOUNTING
359 select CONTEXT_TRACKING
361 Select this option to enable task and CPU time accounting on full
362 dynticks systems. This accounting is implemented by watching every
363 kernel-user boundaries using the context tracking subsystem.
364 The accounting is thus performed at the expense of some significant
367 For now this is only useful if you are working on the full
368 dynticks subsystem development.
372 config IRQ_TIME_ACCOUNTING
373 bool "Fine granularity task level IRQ time accounting"
374 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
376 Select this option to enable fine granularity task irq time
377 accounting. This is done by reading a timestamp on each
378 transitions between softirq and hardirq state, so there can be a
379 small performance impact.
381 If in doubt, say N here.
385 config BSD_PROCESS_ACCT
386 bool "BSD Process Accounting"
388 If you say Y here, a user level program will be able to instruct the
389 kernel (via a special system call) to write process accounting
390 information to a file: whenever a process exits, information about
391 that process will be appended to the file by the kernel. The
392 information includes things such as creation time, owning user,
393 command name, memory usage, controlling terminal etc. (the complete
394 list is in the struct acct in <file:include/linux/acct.h>). It is
395 up to the user level program to do useful things with this
396 information. This is generally a good idea, so say Y.
398 config BSD_PROCESS_ACCT_V3
399 bool "BSD Process Accounting version 3 file format"
400 depends on BSD_PROCESS_ACCT
403 If you say Y here, the process accounting information is written
404 in a new file format that also logs the process IDs of each
405 process and it's parent. Note that this file format is incompatible
406 with previous v0/v1/v2 file formats, so you will need updated tools
407 for processing it. A preliminary version of these tools is available
408 at <http://www.gnu.org/software/acct/>.
411 bool "Export task/process statistics through netlink"
415 Export selected statistics for tasks/processes through the
416 generic netlink interface. Unlike BSD process accounting, the
417 statistics are available during the lifetime of tasks/processes as
418 responses to commands. Like BSD accounting, they are sent to user
423 config TASK_DELAY_ACCT
424 bool "Enable per-task delay accounting"
427 Collect information on time spent by a task waiting for system
428 resources like cpu, synchronous block I/O completion and swapping
429 in pages. Such statistics can help in setting a task's priorities
430 relative to other tasks for cpu, io, rss limits etc.
435 bool "Enable extended accounting over taskstats"
438 Collect extended task accounting data and send the data
439 to userland for processing over the taskstats interface.
443 config TASK_IO_ACCOUNTING
444 bool "Enable per-task storage I/O accounting"
445 depends on TASK_XACCT
447 Collect information on the number of bytes of storage I/O which this
452 endmenu # "CPU/Task time and stats accounting"
457 prompt "RCU Implementation"
461 bool "Tree-based hierarchical RCU"
462 depends on !PREEMPT && SMP
465 This option selects the RCU implementation that is
466 designed for very large SMP system with hundreds or
467 thousands of CPUs. It also scales down nicely to
470 config TREE_PREEMPT_RCU
471 bool "Preemptible tree-based hierarchical RCU"
475 This option selects the RCU implementation that is
476 designed for very large SMP systems with hundreds or
477 thousands of CPUs, but for which real-time response
478 is also required. It also scales down nicely to
481 Select this option if you are unsure.
484 bool "UP-only small-memory-footprint RCU"
485 depends on !PREEMPT && !SMP
487 This option selects the RCU implementation that is
488 designed for UP systems from which real-time response
489 is not required. This option greatly reduces the
490 memory footprint of RCU.
495 def_bool TREE_PREEMPT_RCU
497 This option enables preemptible-RCU code that is common between
498 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
500 config RCU_STALL_COMMON
501 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
503 This option enables RCU CPU stall code that is common between
504 the TINY and TREE variants of RCU. The purpose is to allow
505 the tiny variants to disable RCU CPU stall warnings, while
506 making these warnings mandatory for the tree variants.
508 config CONTEXT_TRACKING
512 bool "Consider userspace as in RCU extended quiescent state"
513 depends on HAVE_CONTEXT_TRACKING && SMP
514 select CONTEXT_TRACKING
516 This option sets hooks on kernel / userspace boundaries and
517 puts RCU in extended quiescent state when the CPU runs in
518 userspace. It means that when a CPU runs in userspace, it is
519 excluded from the global RCU state machine and thus doesn't
520 try to keep the timer tick on for RCU.
522 Unless you want to hack and help the development of the full
523 dynticks mode, you shouldn't enable this option. It also
524 adds unnecessary overhead.
528 config CONTEXT_TRACKING_FORCE
529 bool "Force context tracking"
530 depends on CONTEXT_TRACKING
531 default CONTEXT_TRACKING
533 Probe on user/kernel boundaries by default in order to
534 test the features that rely on it such as userspace RCU extended
536 This test is there for debugging until we have a real user like the
540 int "Tree-based hierarchical RCU fanout value"
543 depends on TREE_RCU || TREE_PREEMPT_RCU
547 This option controls the fanout of hierarchical implementations
548 of RCU, allowing RCU to work efficiently on machines with
549 large numbers of CPUs. This value must be at least the fourth
550 root of NR_CPUS, which allows NR_CPUS to be insanely large.
551 The default value of RCU_FANOUT should be used for production
552 systems, but if you are stress-testing the RCU implementation
553 itself, small RCU_FANOUT values allow you to test large-system
554 code paths on small(er) systems.
556 Select a specific number if testing RCU itself.
557 Take the default if unsure.
559 config RCU_FANOUT_LEAF
560 int "Tree-based hierarchical RCU leaf-level fanout value"
561 range 2 RCU_FANOUT if 64BIT
562 range 2 RCU_FANOUT if !64BIT
563 depends on TREE_RCU || TREE_PREEMPT_RCU
566 This option controls the leaf-level fanout of hierarchical
567 implementations of RCU, and allows trading off cache misses
568 against lock contention. Systems that synchronize their
569 scheduling-clock interrupts for energy-efficiency reasons will
570 want the default because the smaller leaf-level fanout keeps
571 lock contention levels acceptably low. Very large systems
572 (hundreds or thousands of CPUs) will instead want to set this
573 value to the maximum value possible in order to reduce the
574 number of cache misses incurred during RCU's grace-period
575 initialization. These systems tend to run CPU-bound, and thus
576 are not helped by synchronized interrupts, and thus tend to
577 skew them, which reduces lock contention enough that large
578 leaf-level fanouts work well.
580 Select a specific number if testing RCU itself.
582 Select the maximum permissible value for large systems.
584 Take the default if unsure.
586 config RCU_FANOUT_EXACT
587 bool "Disable tree-based hierarchical RCU auto-balancing"
588 depends on TREE_RCU || TREE_PREEMPT_RCU
591 This option forces use of the exact RCU_FANOUT value specified,
592 regardless of imbalances in the hierarchy. This is useful for
593 testing RCU itself, and might one day be useful on systems with
594 strong NUMA behavior.
596 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
600 config RCU_FAST_NO_HZ
601 bool "Accelerate last non-dyntick-idle CPU's grace periods"
602 depends on NO_HZ_COMMON && SMP
605 This option permits CPUs to enter dynticks-idle state even if
606 they have RCU callbacks queued, and prevents RCU from waking
607 these CPUs up more than roughly once every four jiffies (by
608 default, you can adjust this using the rcutree.rcu_idle_gp_delay
609 parameter), thus improving energy efficiency. On the other
610 hand, this option increases the duration of RCU grace periods,
611 for example, slowing down synchronize_rcu().
613 Say Y if energy efficiency is critically important, and you
614 don't care about increased grace-period durations.
616 Say N if you are unsure.
618 config TREE_RCU_TRACE
619 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
622 This option provides tracing for the TREE_RCU and
623 TREE_PREEMPT_RCU implementations, permitting Makefile to
624 trivially select kernel/rcutree_trace.c.
627 bool "Enable RCU priority boosting"
628 depends on RT_MUTEXES && PREEMPT_RCU
631 This option boosts the priority of preempted RCU readers that
632 block the current preemptible RCU grace period for too long.
633 This option also prevents heavy loads from blocking RCU
634 callback invocation for all flavors of RCU.
636 Say Y here if you are working with real-time apps or heavy loads
637 Say N here if you are unsure.
639 config RCU_BOOST_PRIO
640 int "Real-time priority to boost RCU readers to"
645 This option specifies the real-time priority to which long-term
646 preempted RCU readers are to be boosted. If you are working
647 with a real-time application that has one or more CPU-bound
648 threads running at a real-time priority level, you should set
649 RCU_BOOST_PRIO to a priority higher then the highest-priority
650 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
651 of 1 is appropriate in the common case, which is real-time
652 applications that do not have any CPU-bound threads.
654 Some real-time applications might not have a single real-time
655 thread that saturates a given CPU, but instead might have
656 multiple real-time threads that, taken together, fully utilize
657 that CPU. In this case, you should set RCU_BOOST_PRIO to
658 a priority higher than the lowest-priority thread that is
659 conspiring to prevent the CPU from running any non-real-time
660 tasks. For example, if one thread at priority 10 and another
661 thread at priority 5 are between themselves fully consuming
662 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
663 set to priority 6 or higher.
665 Specify the real-time priority, or take the default if unsure.
667 config RCU_BOOST_DELAY
668 int "Milliseconds to delay boosting after RCU grace-period start"
673 This option specifies the time to wait after the beginning of
674 a given grace period before priority-boosting preempted RCU
675 readers blocking that grace period. Note that any RCU reader
676 blocking an expedited RCU grace period is boosted immediately.
678 Accept the default if unsure.
681 bool "Offload RCU callback processing from boot-selected CPUs"
682 depends on TREE_RCU || TREE_PREEMPT_RCU
685 Use this option to reduce OS jitter for aggressive HPC or
686 real-time workloads. It can also be used to offload RCU
687 callback invocation to energy-efficient CPUs in battery-powered
688 asymmetric multiprocessors.
690 This option offloads callback invocation from the set of
691 CPUs specified at boot time by the rcu_nocbs parameter.
692 For each such CPU, a kthread ("rcuox/N") will be created to
693 invoke callbacks, where the "N" is the CPU being offloaded,
694 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
695 "s" for RCU-sched. Nothing prevents this kthread from running
696 on the specified CPUs, but (1) the kthreads may be preempted
697 between each callback, and (2) affinity or cgroups can be used
698 to force the kthreads to run on whatever set of CPUs is desired.
700 Say Y here if you want to help to debug reduced OS jitter.
701 Say N here if you are unsure.
704 prompt "Build-forced no-CBs CPUs"
705 default RCU_NOCB_CPU_NONE
707 This option allows no-CBs CPUs (whose RCU callbacks are invoked
708 from kthreads rather than from softirq context) to be specified
709 at build time. Additional no-CBs CPUs may be specified by
710 the rcu_nocbs= boot parameter.
712 config RCU_NOCB_CPU_NONE
713 bool "No build_forced no-CBs CPUs"
714 depends on RCU_NOCB_CPU && !NO_HZ_FULL
716 This option does not force any of the CPUs to be no-CBs CPUs.
717 Only CPUs designated by the rcu_nocbs= boot parameter will be
718 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
719 kthreads whose names begin with "rcuo". All other CPUs will
720 invoke their own RCU callbacks in softirq context.
722 Select this option if you want to choose no-CBs CPUs at
723 boot time, for example, to allow testing of different no-CBs
724 configurations without having to rebuild the kernel each time.
726 config RCU_NOCB_CPU_ZERO
727 bool "CPU 0 is a build_forced no-CBs CPU"
728 depends on RCU_NOCB_CPU && !NO_HZ_FULL
730 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
731 callbacks are invoked by a per-CPU kthread whose name begins
732 with "rcuo". Additional CPUs may be designated as no-CBs
733 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
734 All other CPUs will invoke their own RCU callbacks in softirq
737 Select this if CPU 0 needs to be a no-CBs CPU for real-time
738 or energy-efficiency reasons, but the real reason it exists
739 is to ensure that randconfig testing covers mixed systems.
741 config RCU_NOCB_CPU_ALL
742 bool "All CPUs are build_forced no-CBs CPUs"
743 depends on RCU_NOCB_CPU
745 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
746 boot parameter will be ignored. All CPUs' RCU callbacks will
747 be executed in the context of per-CPU rcuo kthreads created for
748 this purpose. Assuming that the kthreads whose names start with
749 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
750 on the remaining CPUs, but might decrease memory locality during
751 RCU-callback invocation, thus potentially degrading throughput.
753 Select this if all CPUs need to be no-CBs CPUs for real-time
754 or energy-efficiency reasons.
758 endmenu # "RCU Subsystem"
761 tristate "Kernel .config support"
763 This option enables the complete Linux kernel ".config" file
764 contents to be saved in the kernel. It provides documentation
765 of which kernel options are used in a running kernel or in an
766 on-disk kernel. This information can be extracted from the kernel
767 image file with the script scripts/extract-ikconfig and used as
768 input to rebuild the current kernel or to build another kernel.
769 It can also be extracted from a running kernel by reading
770 /proc/config.gz if enabled (below).
773 bool "Enable access to .config through /proc/config.gz"
774 depends on IKCONFIG && PROC_FS
776 This option enables access to the kernel configuration file
777 through /proc/config.gz.
780 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
784 Select kernel log buffer size as a power of 2.
794 # Architectures with an unreliable sched_clock() should select this:
796 config HAVE_UNSTABLE_SCHED_CLOCK
799 config GENERIC_SCHED_CLOCK
803 # For architectures that want to enable the support for NUMA-affine scheduler
806 config ARCH_SUPPORTS_NUMA_BALANCING
809 # For architectures that (ab)use NUMA to represent different memory regions
810 # all cpu-local but of different latencies, such as SuperH.
812 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
816 # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
817 config ARCH_WANTS_PROT_NUMA_PROT_NONE
820 config ARCH_USES_NUMA_PROT_NONE
823 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
824 depends on NUMA_BALANCING
826 config NUMA_BALANCING_DEFAULT_ENABLED
827 bool "Automatically enable NUMA aware memory/task placement"
829 depends on NUMA_BALANCING
831 If set, autonumic NUMA balancing will be enabled if running on a NUMA
834 config NUMA_BALANCING
835 bool "Memory placement aware NUMA scheduler"
836 depends on ARCH_SUPPORTS_NUMA_BALANCING
837 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
838 depends on SMP && NUMA && MIGRATION
840 This option adds support for automatic NUMA aware memory/task placement.
841 The mechanism is quite primitive and is based on migrating memory when
842 it is references to the node the task is running on.
844 This system will be inactive on UMA systems.
847 boolean "Control Group support"
850 This option adds support for grouping sets of processes together, for
851 use with process control subsystems such as Cpusets, CFS, memory
852 controls or device isolation.
854 - Documentation/scheduler/sched-design-CFS.txt (CFS)
855 - Documentation/cgroups/ (features for grouping, isolation
856 and resource control)
863 bool "Example debug cgroup subsystem"
866 This option enables a simple cgroup subsystem that
867 exports useful debugging information about the cgroups
872 config CGROUP_FREEZER
873 bool "Freezer cgroup subsystem"
875 Provides a way to freeze and unfreeze all tasks in a
879 bool "Device controller for cgroups"
881 Provides a cgroup implementing whitelists for devices which
882 a process in the cgroup can mknod or open.
885 bool "Cpuset support"
887 This option will let you create and manage CPUSETs which
888 allow dynamically partitioning a system into sets of CPUs and
889 Memory Nodes and assigning tasks to run only within those sets.
890 This is primarily useful on large SMP or NUMA systems.
894 config PROC_PID_CPUSET
895 bool "Include legacy /proc/<pid>/cpuset file"
899 config CGROUP_CPUACCT
900 bool "Simple CPU accounting cgroup subsystem"
902 Provides a simple Resource Controller for monitoring the
903 total CPU consumed by the tasks in a cgroup.
905 config RESOURCE_COUNTERS
906 bool "Resource counters"
908 This option enables controller independent resource accounting
909 infrastructure that works with cgroups.
912 bool "Memory Resource Controller for Control Groups"
913 depends on RESOURCE_COUNTERS
916 Provides a memory resource controller that manages both anonymous
917 memory and page cache. (See Documentation/cgroups/memory.txt)
919 Note that setting this option increases fixed memory overhead
920 associated with each page of memory in the system. By this,
921 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
922 usage tracking struct at boot. Total amount of this is printed out
925 Only enable when you're ok with these trade offs and really
926 sure you need the memory resource controller. Even when you enable
927 this, you can set "cgroup_disable=memory" at your boot option to
928 disable memory resource controller and you can avoid overheads.
929 (and lose benefits of memory resource controller)
931 This config option also selects MM_OWNER config option, which
932 could in turn add some fork/exit overhead.
935 bool "Memory Resource Controller Swap Extension"
936 depends on MEMCG && SWAP
938 Add swap management feature to memory resource controller. When you
939 enable this, you can limit mem+swap usage per cgroup. In other words,
940 when you disable this, memory resource controller has no cares to
941 usage of swap...a process can exhaust all of the swap. This extension
942 is useful when you want to avoid exhaustion swap but this itself
943 adds more overheads and consumes memory for remembering information.
944 Especially if you use 32bit system or small memory system, please
945 be careful about enabling this. When memory resource controller
946 is disabled by boot option, this will be automatically disabled and
947 there will be no overhead from this. Even when you set this config=y,
948 if boot option "swapaccount=0" is set, swap will not be accounted.
949 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
950 size is 4096bytes, 512k per 1Gbytes of swap.
951 config MEMCG_SWAP_ENABLED
952 bool "Memory Resource Controller Swap Extension enabled by default"
953 depends on MEMCG_SWAP
956 Memory Resource Controller Swap Extension comes with its price in
957 a bigger memory consumption. General purpose distribution kernels
958 which want to enable the feature but keep it disabled by default
959 and let the user enable it by swapaccount=1 boot command line
960 parameter should have this option unselected.
961 For those who want to have the feature enabled by default should
962 select this option (if, for some reason, they need to disable it
963 then swapaccount=0 does the trick).
965 bool "Memory Resource Controller Kernel Memory accounting"
967 depends on SLUB || SLAB
969 The Kernel Memory extension for Memory Resource Controller can limit
970 the amount of memory used by kernel objects in the system. Those are
971 fundamentally different from the entities handled by the standard
972 Memory Controller, which are page-based, and can be swapped. Users of
973 the kmem extension can use it to guarantee that no group of processes
974 will ever exhaust kernel resources alone.
976 config CGROUP_HUGETLB
977 bool "HugeTLB Resource Controller for Control Groups"
978 depends on RESOURCE_COUNTERS && HUGETLB_PAGE
981 Provides a cgroup Resource Controller for HugeTLB pages.
982 When you enable this, you can put a per cgroup limit on HugeTLB usage.
983 The limit is enforced during page fault. Since HugeTLB doesn't
984 support page reclaim, enforcing the limit at page fault time implies
985 that, the application will get SIGBUS signal if it tries to access
986 HugeTLB pages beyond its limit. This requires the application to know
987 beforehand how much HugeTLB pages it would require for its use. The
988 control group is tracked in the third page lru pointer. This means
989 that we cannot use the controller with huge page less than 3 pages.
992 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
993 depends on PERF_EVENTS && CGROUPS
995 This option extends the per-cpu mode to restrict monitoring to
996 threads which belong to the cgroup specified and run on the
1001 menuconfig CGROUP_SCHED
1002 bool "Group CPU scheduler"
1005 This feature lets CPU scheduler recognize task groups and control CPU
1006 bandwidth allocation to such task groups. It uses cgroups to group
1010 config FAIR_GROUP_SCHED
1011 bool "Group scheduling for SCHED_OTHER"
1012 depends on CGROUP_SCHED
1013 default CGROUP_SCHED
1015 config CFS_BANDWIDTH
1016 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1017 depends on FAIR_GROUP_SCHED
1020 This option allows users to define CPU bandwidth rates (limits) for
1021 tasks running within the fair group scheduler. Groups with no limit
1022 set are considered to be unconstrained and will run with no
1024 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1026 config RT_GROUP_SCHED
1027 bool "Group scheduling for SCHED_RR/FIFO"
1028 depends on CGROUP_SCHED
1031 This feature lets you explicitly allocate real CPU bandwidth
1032 to task groups. If enabled, it will also make it impossible to
1033 schedule realtime tasks for non-root users until you allocate
1034 realtime bandwidth for them.
1035 See Documentation/scheduler/sched-rt-group.txt for more information.
1040 bool "Block IO controller"
1044 Generic block IO controller cgroup interface. This is the common
1045 cgroup interface which should be used by various IO controlling
1048 Currently, CFQ IO scheduler uses it to recognize task groups and
1049 control disk bandwidth allocation (proportional time slice allocation)
1050 to such task groups. It is also used by bio throttling logic in
1051 block layer to implement upper limit in IO rates on a device.
1053 This option only enables generic Block IO controller infrastructure.
1054 One needs to also enable actual IO controlling logic/policy. For
1055 enabling proportional weight division of disk bandwidth in CFQ, set
1056 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1057 CONFIG_BLK_DEV_THROTTLING=y.
1059 See Documentation/cgroups/blkio-controller.txt for more information.
1061 config DEBUG_BLK_CGROUP
1062 bool "Enable Block IO controller debugging"
1063 depends on BLK_CGROUP
1066 Enable some debugging help. Currently it exports additional stat
1067 files in a cgroup which can be useful for debugging.
1071 config CHECKPOINT_RESTORE
1072 bool "Checkpoint/restore support" if EXPERT
1075 Enables additional kernel features in a sake of checkpoint/restore.
1076 In particular it adds auxiliary prctl codes to setup process text,
1077 data and heap segment sizes, and a few additional /proc filesystem
1080 If unsure, say N here.
1082 menuconfig NAMESPACES
1083 bool "Namespaces support" if EXPERT
1086 Provides the way to make tasks work with different objects using
1087 the same id. For example same IPC id may refer to different objects
1088 or same user id or pid may refer to different tasks when used in
1089 different namespaces.
1094 bool "UTS namespace"
1097 In this namespace tasks see different info provided with the
1101 bool "IPC namespace"
1102 depends on (SYSVIPC || POSIX_MQUEUE)
1105 In this namespace tasks work with IPC ids which correspond to
1106 different IPC objects in different namespaces.
1109 bool "User namespace"
1110 depends on UIDGID_CONVERTED
1111 select UIDGID_STRICT_TYPE_CHECKS
1115 This allows containers, i.e. vservers, to use user namespaces
1116 to provide different user info for different servers.
1118 When user namespaces are enabled in the kernel it is
1119 recommended that the MEMCG and MEMCG_KMEM options also be
1120 enabled and that user-space use the memory control groups to
1121 limit the amount of memory a memory unprivileged users can
1127 bool "PID Namespaces"
1130 Support process id namespaces. This allows having multiple
1131 processes with the same pid as long as they are in different
1132 pid namespaces. This is a building block of containers.
1135 bool "Network namespace"
1139 Allow user space to create what appear to be multiple instances
1140 of the network stack.
1144 config UIDGID_CONVERTED
1145 # True if all of the selected software conmponents are known
1146 # to have uid_t and gid_t converted to kuid_t and kgid_t
1147 # where appropriate and are otherwise safe to use with
1148 # the user namespace.
1153 depends on XFS_FS = n
1155 config UIDGID_STRICT_TYPE_CHECKS
1156 bool "Require conversions between uid/gids and their internal representation"
1157 depends on UIDGID_CONVERTED
1160 While the nececessary conversions are being added to all subsystems this option allows
1161 the code to continue to build for unconverted subsystems.
1163 Say Y here if you want the strict type checking enabled
1165 config SCHED_AUTOGROUP
1166 bool "Automatic process group scheduling"
1170 select FAIR_GROUP_SCHED
1172 This option optimizes the scheduler for common desktop workloads by
1173 automatically creating and populating task groups. This separation
1174 of workloads isolates aggressive CPU burners (like build jobs) from
1175 desktop applications. Task group autogeneration is currently based
1181 config SYSFS_DEPRECATED
1182 bool "Enable deprecated sysfs features to support old userspace tools"
1186 This option adds code that switches the layout of the "block" class
1187 devices, to not show up in /sys/class/block/, but only in
1190 This switch is only active when the sysfs.deprecated=1 boot option is
1191 passed or the SYSFS_DEPRECATED_V2 option is set.
1193 This option allows new kernels to run on old distributions and tools,
1194 which might get confused by /sys/class/block/. Since 2007/2008 all
1195 major distributions and tools handle this just fine.
1197 Recent distributions and userspace tools after 2009/2010 depend on
1198 the existence of /sys/class/block/, and will not work with this
1201 Only if you are using a new kernel on an old distribution, you might
1204 config SYSFS_DEPRECATED_V2
1205 bool "Enable deprecated sysfs features by default"
1208 depends on SYSFS_DEPRECATED
1210 Enable deprecated sysfs by default.
1212 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1215 Only if you are using a new kernel on an old distribution, you might
1216 need to say Y here. Even then, odds are you would not need it
1217 enabled, you can always pass the boot option if absolutely necessary.
1220 bool "Kernel->user space relay support (formerly relayfs)"
1222 This option enables support for relay interface support in
1223 certain file systems (such as debugfs).
1224 It is designed to provide an efficient mechanism for tools and
1225 facilities to relay large amounts of data from kernel space to
1230 config BLK_DEV_INITRD
1231 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1232 depends on BROKEN || !FRV
1234 The initial RAM filesystem is a ramfs which is loaded by the
1235 boot loader (loadlin or lilo) and that is mounted as root
1236 before the normal boot procedure. It is typically used to
1237 load modules needed to mount the "real" root file system,
1238 etc. See <file:Documentation/initrd.txt> for details.
1240 If RAM disk support (BLK_DEV_RAM) is also included, this
1241 also enables initial RAM disk (initrd) support and adds
1242 15 Kbytes (more on some other architectures) to the kernel size.
1248 source "usr/Kconfig"
1252 config CC_OPTIMIZE_FOR_SIZE
1253 bool "Optimize for size"
1255 Enabling this option will pass "-Os" instead of "-O2" to gcc
1256 resulting in a smaller kernel.
1269 config SYSCTL_EXCEPTION_TRACE
1272 Enable support for /proc/sys/debug/exception-trace.
1274 config SYSCTL_ARCH_UNALIGN_NO_WARN
1277 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1278 Allows arch to define/use @no_unaligned_warning to possibly warn
1279 about unaligned access emulation going on under the hood.
1281 config SYSCTL_ARCH_UNALIGN_ALLOW
1284 Enable support for /proc/sys/kernel/unaligned-trap
1285 Allows arches to define/use @unaligned_enabled to runtime toggle
1286 the unaligned access emulation.
1287 see arch/parisc/kernel/unaligned.c for reference
1289 config HAVE_PCSPKR_PLATFORM
1293 bool "Configure standard kernel features (expert users)"
1294 # Unhide debug options, to make the on-by-default options visible
1297 This option allows certain base kernel options and settings
1298 to be disabled or tweaked. This is for specialized
1299 environments which can tolerate a "non-standard" kernel.
1300 Only use this if you really know what you are doing.
1303 bool "Enable 16-bit UID system calls" if EXPERT
1304 depends on HAVE_UID16
1307 This enables the legacy 16-bit UID syscall wrappers.
1309 config SYSCTL_SYSCALL
1310 bool "Sysctl syscall support" if EXPERT
1311 depends on PROC_SYSCTL
1315 sys_sysctl uses binary paths that have been found challenging
1316 to properly maintain and use. The interface in /proc/sys
1317 using paths with ascii names is now the primary path to this
1320 Almost nothing using the binary sysctl interface so if you are
1321 trying to save some space it is probably safe to disable this,
1322 making your kernel marginally smaller.
1324 If unsure say N here.
1327 bool "Load all symbols for debugging/ksymoops" if EXPERT
1330 Say Y here to let the kernel print out symbolic crash information and
1331 symbolic stack backtraces. This increases the size of the kernel
1332 somewhat, as all symbols have to be loaded into the kernel image.
1335 bool "Include all symbols in kallsyms"
1336 depends on DEBUG_KERNEL && KALLSYMS
1338 Normally kallsyms only contains the symbols of functions for nicer
1339 OOPS messages and backtraces (i.e., symbols from the text and inittext
1340 sections). This is sufficient for most cases. And only in very rare
1341 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1342 names of variables from the data sections, etc).
1344 This option makes sure that all symbols are loaded into the kernel
1345 image (i.e., symbols from all sections) in cost of increased kernel
1346 size (depending on the kernel configuration, it may be 300KiB or
1347 something like this).
1349 Say N unless you really need all symbols.
1353 bool "Enable support for printk" if EXPERT
1356 This option enables normal printk support. Removing it
1357 eliminates most of the message strings from the kernel image
1358 and makes the kernel more or less silent. As this makes it
1359 very difficult to diagnose system problems, saying N here is
1360 strongly discouraged.
1363 bool "BUG() support" if EXPERT
1366 Disabling this option eliminates support for BUG and WARN, reducing
1367 the size of your kernel image and potentially quietly ignoring
1368 numerous fatal conditions. You should only consider disabling this
1369 option for embedded systems with no facilities for reporting errors.
1375 bool "Enable ELF core dumps" if EXPERT
1377 Enable support for generating core dumps. Disabling saves about 4k.
1380 config PCSPKR_PLATFORM
1381 bool "Enable PC-Speaker support" if EXPERT
1382 depends on HAVE_PCSPKR_PLATFORM
1386 This option allows to disable the internal PC-Speaker
1387 support, saving some memory.
1391 bool "Enable full-sized data structures for core" if EXPERT
1393 Disabling this option reduces the size of miscellaneous core
1394 kernel data structures. This saves memory on small machines,
1395 but may reduce performance.
1398 bool "Enable futex support" if EXPERT
1402 Disabling this option will cause the kernel to be built without
1403 support for "fast userspace mutexes". The resulting kernel may not
1404 run glibc-based applications correctly.
1407 bool "Enable eventpoll support" if EXPERT
1411 Disabling this option will cause the kernel to be built without
1412 support for epoll family of system calls.
1415 bool "Enable signalfd() system call" if EXPERT
1419 Enable the signalfd() system call that allows to receive signals
1420 on a file descriptor.
1425 bool "Enable timerfd() system call" if EXPERT
1429 Enable the timerfd() system call that allows to receive timer
1430 events on a file descriptor.
1435 bool "Enable eventfd() system call" if EXPERT
1439 Enable the eventfd() system call that allows to receive both
1440 kernel notification (ie. KAIO) or userspace notifications.
1445 bool "Use full shmem filesystem" if EXPERT
1449 The shmem is an internal filesystem used to manage shared memory.
1450 It is backed by swap and manages resource limits. It is also exported
1451 to userspace as tmpfs if TMPFS is enabled. Disabling this
1452 option replaces shmem and tmpfs with the much simpler ramfs code,
1453 which may be appropriate on small systems without swap.
1456 bool "Enable AIO support" if EXPERT
1459 This option enables POSIX asynchronous I/O which may by used
1460 by some high performance threaded applications. Disabling
1461 this option saves about 7k.
1465 bool "Enable PCI quirk workarounds" if EXPERT
1468 This enables workarounds for various PCI chipset
1469 bugs/quirks. Disable this only if your target machine is
1470 unaffected by PCI quirks.
1473 bool "Embedded system"
1476 This option should be enabled if compiling the kernel for
1477 an embedded system so certain expert options are available
1480 config HAVE_PERF_EVENTS
1483 See tools/perf/design.txt for details.
1485 config PERF_USE_VMALLOC
1488 See tools/perf/design.txt for details
1490 menu "Kernel Performance Events And Counters"
1493 bool "Kernel performance events and counters"
1494 default y if PROFILING
1495 depends on HAVE_PERF_EVENTS
1499 Enable kernel support for various performance events provided
1500 by software and hardware.
1502 Software events are supported either built-in or via the
1503 use of generic tracepoints.
1505 Most modern CPUs support performance events via performance
1506 counter registers. These registers count the number of certain
1507 types of hw events: such as instructions executed, cachemisses
1508 suffered, or branches mis-predicted - without slowing down the
1509 kernel or applications. These registers can also trigger interrupts
1510 when a threshold number of events have passed - and can thus be
1511 used to profile the code that runs on that CPU.
1513 The Linux Performance Event subsystem provides an abstraction of
1514 these software and hardware event capabilities, available via a
1515 system call and used by the "perf" utility in tools/perf/. It
1516 provides per task and per CPU counters, and it provides event
1517 capabilities on top of those.
1521 config DEBUG_PERF_USE_VMALLOC
1523 bool "Debug: use vmalloc to back perf mmap() buffers"
1524 depends on PERF_EVENTS && DEBUG_KERNEL
1525 select PERF_USE_VMALLOC
1527 Use vmalloc memory to back perf mmap() buffers.
1529 Mostly useful for debugging the vmalloc code on platforms
1530 that don't require it.
1536 config VM_EVENT_COUNTERS
1538 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1540 VM event counters are needed for event counts to be shown.
1541 This option allows the disabling of the VM event counters
1542 on EXPERT systems. /proc/vmstat will only show page counts
1543 if VM event counters are disabled.
1547 bool "Enable SLUB debugging support" if EXPERT
1548 depends on SLUB && SYSFS
1550 SLUB has extensive debug support features. Disabling these can
1551 result in significant savings in code size. This also disables
1552 SLUB sysfs support. /sys/slab will not exist and there will be
1553 no support for cache validation etc.
1556 bool "Disable heap randomization"
1559 Randomizing heap placement makes heap exploits harder, but it
1560 also breaks ancient binaries (including anything libc5 based).
1561 This option changes the bootup default to heap randomization
1562 disabled, and can be overridden at runtime by setting
1563 /proc/sys/kernel/randomize_va_space to 2.
1565 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1568 prompt "Choose SLAB allocator"
1571 This option allows to select a slab allocator.
1576 The regular slab allocator that is established and known to work
1577 well in all environments. It organizes cache hot objects in
1578 per cpu and per node queues.
1581 bool "SLUB (Unqueued Allocator)"
1583 SLUB is a slab allocator that minimizes cache line usage
1584 instead of managing queues of cached objects (SLAB approach).
1585 Per cpu caching is realized using slabs of objects instead
1586 of queues of objects. SLUB can use memory efficiently
1587 and has enhanced diagnostics. SLUB is the default choice for
1592 bool "SLOB (Simple Allocator)"
1594 SLOB replaces the stock allocator with a drastically simpler
1595 allocator. SLOB is generally more space efficient but
1596 does not perform as well on large systems.
1600 config SLUB_CPU_PARTIAL
1603 bool "SLUB per cpu partial cache"
1605 Per cpu partial caches accellerate objects allocation and freeing
1606 that is local to a processor at the price of more indeterminism
1607 in the latency of the free. On overflow these caches will be cleared
1608 which requires the taking of locks that may cause latency spikes.
1609 Typically one would choose no for a realtime system.
1611 config MMAP_ALLOW_UNINITIALIZED
1612 bool "Allow mmapped anonymous memory to be uninitialized"
1613 depends on EXPERT && !MMU
1616 Normally, and according to the Linux spec, anonymous memory obtained
1617 from mmap() has it's contents cleared before it is passed to
1618 userspace. Enabling this config option allows you to request that
1619 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1620 providing a huge performance boost. If this option is not enabled,
1621 then the flag will be ignored.
1623 This is taken advantage of by uClibc's malloc(), and also by
1624 ELF-FDPIC binfmt's brk and stack allocator.
1626 Because of the obvious security issues, this option should only be
1627 enabled on embedded devices where you control what is run in
1628 userspace. Since that isn't generally a problem on no-MMU systems,
1629 it is normally safe to say Y here.
1631 See Documentation/nommu-mmap.txt for more information.
1634 bool "Profiling support"
1636 Say Y here to enable the extended profiling support mechanisms used
1637 by profilers such as OProfile.
1640 # Place an empty function call at each tracepoint site. Can be
1641 # dynamically changed for a probe function.
1646 source "arch/Kconfig"
1648 endmenu # General setup
1650 config HAVE_GENERIC_DMA_COHERENT
1657 depends on SLAB || SLUB_DEBUG
1665 default 0 if BASE_FULL
1666 default 1 if !BASE_FULL
1669 bool "Enable loadable module support"
1671 Kernel modules are small pieces of compiled code which can
1672 be inserted in the running kernel, rather than being
1673 permanently built into the kernel. You use the "modprobe"
1674 tool to add (and sometimes remove) them. If you say Y here,
1675 many parts of the kernel can be built as modules (by
1676 answering M instead of Y where indicated): this is most
1677 useful for infrequently used options which are not required
1678 for booting. For more information, see the man pages for
1679 modprobe, lsmod, modinfo, insmod and rmmod.
1681 If you say Y here, you will need to run "make
1682 modules_install" to put the modules under /lib/modules/
1683 where modprobe can find them (you may need to be root to do
1690 config MODULE_FORCE_LOAD
1691 bool "Forced module loading"
1694 Allow loading of modules without version information (ie. modprobe
1695 --force). Forced module loading sets the 'F' (forced) taint flag and
1696 is usually a really bad idea.
1698 config MODULE_UNLOAD
1699 bool "Module unloading"
1701 Without this option you will not be able to unload any
1702 modules (note that some modules may not be unloadable
1703 anyway), which makes your kernel smaller, faster
1704 and simpler. If unsure, say Y.
1706 config MODULE_FORCE_UNLOAD
1707 bool "Forced module unloading"
1708 depends on MODULE_UNLOAD
1710 This option allows you to force a module to unload, even if the
1711 kernel believes it is unsafe: the kernel will remove the module
1712 without waiting for anyone to stop using it (using the -f option to
1713 rmmod). This is mainly for kernel developers and desperate users.
1717 bool "Module versioning support"
1719 Usually, you have to use modules compiled with your kernel.
1720 Saying Y here makes it sometimes possible to use modules
1721 compiled for different kernels, by adding enough information
1722 to the modules to (hopefully) spot any changes which would
1723 make them incompatible with the kernel you are running. If
1726 config MODULE_SRCVERSION_ALL
1727 bool "Source checksum for all modules"
1729 Modules which contain a MODULE_VERSION get an extra "srcversion"
1730 field inserted into their modinfo section, which contains a
1731 sum of the source files which made it. This helps maintainers
1732 see exactly which source was used to build a module (since
1733 others sometimes change the module source without updating
1734 the version). With this option, such a "srcversion" field
1735 will be created for all modules. If unsure, say N.
1738 bool "Module signature verification"
1742 select ASYMMETRIC_KEY_TYPE
1743 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1744 select PUBLIC_KEY_ALGO_RSA
1747 select X509_CERTIFICATE_PARSER
1749 Check modules for valid signatures upon load: the signature
1750 is simply appended to the module. For more information see
1751 Documentation/module-signing.txt.
1753 !!!WARNING!!! If you enable this option, you MUST make sure that the
1754 module DOES NOT get stripped after being signed. This includes the
1755 debuginfo strip done by some packagers (such as rpmbuild) and
1756 inclusion into an initramfs that wants the module size reduced.
1758 config MODULE_SIG_FORCE
1759 bool "Require modules to be validly signed"
1760 depends on MODULE_SIG
1762 Reject unsigned modules or signed modules for which we don't have a
1763 key. Without this, such modules will simply taint the kernel.
1765 config MODULE_SIG_ALL
1766 bool "Automatically sign all modules"
1768 depends on MODULE_SIG
1770 Sign all modules during make modules_install. Without this option,
1771 modules must be signed manually, using the scripts/sign-file tool.
1773 comment "Do not forget to sign required modules with scripts/sign-file"
1774 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1777 prompt "Which hash algorithm should modules be signed with?"
1778 depends on MODULE_SIG
1780 This determines which sort of hashing algorithm will be used during
1781 signature generation. This algorithm _must_ be built into the kernel
1782 directly so that signature verification can take place. It is not
1783 possible to load a signed module containing the algorithm to check
1784 the signature on that module.
1786 config MODULE_SIG_SHA1
1787 bool "Sign modules with SHA-1"
1790 config MODULE_SIG_SHA224
1791 bool "Sign modules with SHA-224"
1792 select CRYPTO_SHA256
1794 config MODULE_SIG_SHA256
1795 bool "Sign modules with SHA-256"
1796 select CRYPTO_SHA256
1798 config MODULE_SIG_SHA384
1799 bool "Sign modules with SHA-384"
1800 select CRYPTO_SHA512
1802 config MODULE_SIG_SHA512
1803 bool "Sign modules with SHA-512"
1804 select CRYPTO_SHA512
1808 config MODULE_SIG_HASH
1810 depends on MODULE_SIG
1811 default "sha1" if MODULE_SIG_SHA1
1812 default "sha224" if MODULE_SIG_SHA224
1813 default "sha256" if MODULE_SIG_SHA256
1814 default "sha384" if MODULE_SIG_SHA384
1815 default "sha512" if MODULE_SIG_SHA512
1819 config INIT_ALL_POSSIBLE
1822 Back when each arch used to define their own cpu_online_mask and
1823 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1824 with all 1s, and others with all 0s. When they were centralised,
1825 it was better to provide this option than to break all the archs
1826 and have several arch maintainers pursuing me down dark alleys.
1831 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1833 Need stop_machine() primitive.
1835 source "block/Kconfig"
1837 config PREEMPT_NOTIFIERS
1844 # Can be selected by architectures with broken toolchains
1845 # that get confused by correct const<->read_only section
1847 config BROKEN_RODATA
1853 Build a simple ASN.1 grammar compiler that produces a bytecode output
1854 that can be interpreted by the ASN.1 stream decoder and used to
1855 inform it as to what tags are to be expected in a stream and what
1856 functions to call on what tags.
1858 source "kernel/Kconfig.locks"
projects / linux-2.6-block.git / blob