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.
285 config HAVE_ARCH_AUDITSYSCALL
289 bool "Enable system-call auditing support"
290 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
291 default y if SECURITY_SELINUX
293 Enable low-overhead system-call auditing infrastructure that
294 can be used independently or with another kernel subsystem,
299 depends on AUDITSYSCALL
304 depends on AUDITSYSCALL
307 source "kernel/irq/Kconfig"
308 source "kernel/time/Kconfig"
310 menu "CPU/Task time and stats accounting"
312 config VIRT_CPU_ACCOUNTING
316 prompt "Cputime accounting"
317 default TICK_CPU_ACCOUNTING if !PPC64
318 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
320 # Kind of a stub config for the pure tick based cputime accounting
321 config TICK_CPU_ACCOUNTING
322 bool "Simple tick based cputime accounting"
323 depends on !S390 && !NO_HZ_FULL
325 This is the basic tick based cputime accounting that maintains
326 statistics about user, system and idle time spent on per jiffies
331 config VIRT_CPU_ACCOUNTING_NATIVE
332 bool "Deterministic task and CPU time accounting"
333 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
334 select VIRT_CPU_ACCOUNTING
336 Select this option to enable more accurate task and CPU time
337 accounting. This is done by reading a CPU counter on each
338 kernel entry and exit and on transitions within the kernel
339 between system, softirq and hardirq state, so there is a
340 small performance impact. In the case of s390 or IBM POWER > 5,
341 this also enables accounting of stolen time on logically-partitioned
344 config VIRT_CPU_ACCOUNTING_GEN
345 bool "Full dynticks CPU time accounting"
346 depends on HAVE_CONTEXT_TRACKING
347 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
348 select VIRT_CPU_ACCOUNTING
349 select CONTEXT_TRACKING
351 Select this option to enable task and CPU time accounting on full
352 dynticks systems. This accounting is implemented by watching every
353 kernel-user boundaries using the context tracking subsystem.
354 The accounting is thus performed at the expense of some significant
357 For now this is only useful if you are working on the full
358 dynticks subsystem development.
362 config IRQ_TIME_ACCOUNTING
363 bool "Fine granularity task level IRQ time accounting"
364 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
366 Select this option to enable fine granularity task irq time
367 accounting. This is done by reading a timestamp on each
368 transitions between softirq and hardirq state, so there can be a
369 small performance impact.
371 If in doubt, say N here.
375 config BSD_PROCESS_ACCT
376 bool "BSD Process Accounting"
378 If you say Y here, a user level program will be able to instruct the
379 kernel (via a special system call) to write process accounting
380 information to a file: whenever a process exits, information about
381 that process will be appended to the file by the kernel. The
382 information includes things such as creation time, owning user,
383 command name, memory usage, controlling terminal etc. (the complete
384 list is in the struct acct in <file:include/linux/acct.h>). It is
385 up to the user level program to do useful things with this
386 information. This is generally a good idea, so say Y.
388 config BSD_PROCESS_ACCT_V3
389 bool "BSD Process Accounting version 3 file format"
390 depends on BSD_PROCESS_ACCT
393 If you say Y here, the process accounting information is written
394 in a new file format that also logs the process IDs of each
395 process and it's parent. Note that this file format is incompatible
396 with previous v0/v1/v2 file formats, so you will need updated tools
397 for processing it. A preliminary version of these tools is available
398 at <http://www.gnu.org/software/acct/>.
401 bool "Export task/process statistics through netlink"
405 Export selected statistics for tasks/processes through the
406 generic netlink interface. Unlike BSD process accounting, the
407 statistics are available during the lifetime of tasks/processes as
408 responses to commands. Like BSD accounting, they are sent to user
413 config TASK_DELAY_ACCT
414 bool "Enable per-task delay accounting"
417 Collect information on time spent by a task waiting for system
418 resources like cpu, synchronous block I/O completion and swapping
419 in pages. Such statistics can help in setting a task's priorities
420 relative to other tasks for cpu, io, rss limits etc.
425 bool "Enable extended accounting over taskstats"
428 Collect extended task accounting data and send the data
429 to userland for processing over the taskstats interface.
433 config TASK_IO_ACCOUNTING
434 bool "Enable per-task storage I/O accounting"
435 depends on TASK_XACCT
437 Collect information on the number of bytes of storage I/O which this
442 endmenu # "CPU/Task time and stats accounting"
447 prompt "RCU Implementation"
451 bool "Tree-based hierarchical RCU"
452 depends on !PREEMPT && SMP
455 This option selects the RCU implementation that is
456 designed for very large SMP system with hundreds or
457 thousands of CPUs. It also scales down nicely to
460 config TREE_PREEMPT_RCU
461 bool "Preemptible tree-based hierarchical RCU"
465 This option selects the RCU implementation that is
466 designed for very large SMP systems with hundreds or
467 thousands of CPUs, but for which real-time response
468 is also required. It also scales down nicely to
471 Select this option if you are unsure.
474 bool "UP-only small-memory-footprint RCU"
475 depends on !PREEMPT && !SMP
477 This option selects the RCU implementation that is
478 designed for UP systems from which real-time response
479 is not required. This option greatly reduces the
480 memory footprint of RCU.
485 def_bool TREE_PREEMPT_RCU
487 This option enables preemptible-RCU code that is common between
488 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
490 config RCU_STALL_COMMON
491 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
493 This option enables RCU CPU stall code that is common between
494 the TINY and TREE variants of RCU. The purpose is to allow
495 the tiny variants to disable RCU CPU stall warnings, while
496 making these warnings mandatory for the tree variants.
498 config CONTEXT_TRACKING
502 bool "Consider userspace as in RCU extended quiescent state"
503 depends on HAVE_CONTEXT_TRACKING && SMP
504 select CONTEXT_TRACKING
506 This option sets hooks on kernel / userspace boundaries and
507 puts RCU in extended quiescent state when the CPU runs in
508 userspace. It means that when a CPU runs in userspace, it is
509 excluded from the global RCU state machine and thus doesn't
510 try to keep the timer tick on for RCU.
512 Unless you want to hack and help the development of the full
513 dynticks mode, you shouldn't enable this option. It also
514 adds unnecessary overhead.
518 config CONTEXT_TRACKING_FORCE
519 bool "Force context tracking"
520 depends on CONTEXT_TRACKING
521 default y if !NO_HZ_FULL
523 The major pre-requirement for full dynticks to work is to
524 support the context tracking subsystem. But there are also
525 other dependencies to provide in order to make the full
528 This option stands for testing when an arch implements the
529 context tracking backend but doesn't yet fullfill all the
530 requirements to make the full dynticks feature working.
531 Without the full dynticks, there is no way to test the support
532 for context tracking and the subsystems that rely on it: RCU
533 userspace extended quiescent state and tickless cputime
534 accounting. This option copes with the absence of the full
535 dynticks subsystem by forcing the context tracking on all
538 Say Y only if you're working on the developpement of an
539 architecture backend for the context tracking.
541 Say N otherwise, this option brings an overhead that you
542 don't want in production.
546 int "Tree-based hierarchical RCU fanout value"
549 depends on TREE_RCU || TREE_PREEMPT_RCU
553 This option controls the fanout of hierarchical implementations
554 of RCU, allowing RCU to work efficiently on machines with
555 large numbers of CPUs. This value must be at least the fourth
556 root of NR_CPUS, which allows NR_CPUS to be insanely large.
557 The default value of RCU_FANOUT should be used for production
558 systems, but if you are stress-testing the RCU implementation
559 itself, small RCU_FANOUT values allow you to test large-system
560 code paths on small(er) systems.
562 Select a specific number if testing RCU itself.
563 Take the default if unsure.
565 config RCU_FANOUT_LEAF
566 int "Tree-based hierarchical RCU leaf-level fanout value"
567 range 2 RCU_FANOUT if 64BIT
568 range 2 RCU_FANOUT if !64BIT
569 depends on TREE_RCU || TREE_PREEMPT_RCU
572 This option controls the leaf-level fanout of hierarchical
573 implementations of RCU, and allows trading off cache misses
574 against lock contention. Systems that synchronize their
575 scheduling-clock interrupts for energy-efficiency reasons will
576 want the default because the smaller leaf-level fanout keeps
577 lock contention levels acceptably low. Very large systems
578 (hundreds or thousands of CPUs) will instead want to set this
579 value to the maximum value possible in order to reduce the
580 number of cache misses incurred during RCU's grace-period
581 initialization. These systems tend to run CPU-bound, and thus
582 are not helped by synchronized interrupts, and thus tend to
583 skew them, which reduces lock contention enough that large
584 leaf-level fanouts work well.
586 Select a specific number if testing RCU itself.
588 Select the maximum permissible value for large systems.
590 Take the default if unsure.
592 config RCU_FANOUT_EXACT
593 bool "Disable tree-based hierarchical RCU auto-balancing"
594 depends on TREE_RCU || TREE_PREEMPT_RCU
597 This option forces use of the exact RCU_FANOUT value specified,
598 regardless of imbalances in the hierarchy. This is useful for
599 testing RCU itself, and might one day be useful on systems with
600 strong NUMA behavior.
602 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
606 config RCU_FAST_NO_HZ
607 bool "Accelerate last non-dyntick-idle CPU's grace periods"
608 depends on NO_HZ_COMMON && SMP
611 This option permits CPUs to enter dynticks-idle state even if
612 they have RCU callbacks queued, and prevents RCU from waking
613 these CPUs up more than roughly once every four jiffies (by
614 default, you can adjust this using the rcutree.rcu_idle_gp_delay
615 parameter), thus improving energy efficiency. On the other
616 hand, this option increases the duration of RCU grace periods,
617 for example, slowing down synchronize_rcu().
619 Say Y if energy efficiency is critically important, and you
620 don't care about increased grace-period durations.
622 Say N if you are unsure.
624 config TREE_RCU_TRACE
625 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
628 This option provides tracing for the TREE_RCU and
629 TREE_PREEMPT_RCU implementations, permitting Makefile to
630 trivially select kernel/rcutree_trace.c.
633 bool "Enable RCU priority boosting"
634 depends on RT_MUTEXES && PREEMPT_RCU
637 This option boosts the priority of preempted RCU readers that
638 block the current preemptible RCU grace period for too long.
639 This option also prevents heavy loads from blocking RCU
640 callback invocation for all flavors of RCU.
642 Say Y here if you are working with real-time apps or heavy loads
643 Say N here if you are unsure.
645 config RCU_BOOST_PRIO
646 int "Real-time priority to boost RCU readers to"
651 This option specifies the real-time priority to which long-term
652 preempted RCU readers are to be boosted. If you are working
653 with a real-time application that has one or more CPU-bound
654 threads running at a real-time priority level, you should set
655 RCU_BOOST_PRIO to a priority higher then the highest-priority
656 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
657 of 1 is appropriate in the common case, which is real-time
658 applications that do not have any CPU-bound threads.
660 Some real-time applications might not have a single real-time
661 thread that saturates a given CPU, but instead might have
662 multiple real-time threads that, taken together, fully utilize
663 that CPU. In this case, you should set RCU_BOOST_PRIO to
664 a priority higher than the lowest-priority thread that is
665 conspiring to prevent the CPU from running any non-real-time
666 tasks. For example, if one thread at priority 10 and another
667 thread at priority 5 are between themselves fully consuming
668 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
669 set to priority 6 or higher.
671 Specify the real-time priority, or take the default if unsure.
673 config RCU_BOOST_DELAY
674 int "Milliseconds to delay boosting after RCU grace-period start"
679 This option specifies the time to wait after the beginning of
680 a given grace period before priority-boosting preempted RCU
681 readers blocking that grace period. Note that any RCU reader
682 blocking an expedited RCU grace period is boosted immediately.
684 Accept the default if unsure.
687 bool "Offload RCU callback processing from boot-selected CPUs"
688 depends on TREE_RCU || TREE_PREEMPT_RCU
691 Use this option to reduce OS jitter for aggressive HPC or
692 real-time workloads. It can also be used to offload RCU
693 callback invocation to energy-efficient CPUs in battery-powered
694 asymmetric multiprocessors.
696 This option offloads callback invocation from the set of
697 CPUs specified at boot time by the rcu_nocbs parameter.
698 For each such CPU, a kthread ("rcuox/N") will be created to
699 invoke callbacks, where the "N" is the CPU being offloaded,
700 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
701 "s" for RCU-sched. Nothing prevents this kthread from running
702 on the specified CPUs, but (1) the kthreads may be preempted
703 between each callback, and (2) affinity or cgroups can be used
704 to force the kthreads to run on whatever set of CPUs is desired.
706 Say Y here if you want to help to debug reduced OS jitter.
707 Say N here if you are unsure.
710 prompt "Build-forced no-CBs CPUs"
711 default RCU_NOCB_CPU_NONE
713 This option allows no-CBs CPUs (whose RCU callbacks are invoked
714 from kthreads rather than from softirq context) to be specified
715 at build time. Additional no-CBs CPUs may be specified by
716 the rcu_nocbs= boot parameter.
718 config RCU_NOCB_CPU_NONE
719 bool "No build_forced no-CBs CPUs"
720 depends on RCU_NOCB_CPU && !NO_HZ_FULL
722 This option does not force any of the CPUs to be no-CBs CPUs.
723 Only CPUs designated by the rcu_nocbs= boot parameter will be
724 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
725 kthreads whose names begin with "rcuo". All other CPUs will
726 invoke their own RCU callbacks in softirq context.
728 Select this option if you want to choose no-CBs CPUs at
729 boot time, for example, to allow testing of different no-CBs
730 configurations without having to rebuild the kernel each time.
732 config RCU_NOCB_CPU_ZERO
733 bool "CPU 0 is a build_forced no-CBs CPU"
734 depends on RCU_NOCB_CPU && !NO_HZ_FULL
736 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
737 callbacks are invoked by a per-CPU kthread whose name begins
738 with "rcuo". Additional CPUs may be designated as no-CBs
739 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
740 All other CPUs will invoke their own RCU callbacks in softirq
743 Select this if CPU 0 needs to be a no-CBs CPU for real-time
744 or energy-efficiency reasons, but the real reason it exists
745 is to ensure that randconfig testing covers mixed systems.
747 config RCU_NOCB_CPU_ALL
748 bool "All CPUs are build_forced no-CBs CPUs"
749 depends on RCU_NOCB_CPU
751 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
752 boot parameter will be ignored. All CPUs' RCU callbacks will
753 be executed in the context of per-CPU rcuo kthreads created for
754 this purpose. Assuming that the kthreads whose names start with
755 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
756 on the remaining CPUs, but might decrease memory locality during
757 RCU-callback invocation, thus potentially degrading throughput.
759 Select this if all CPUs need to be no-CBs CPUs for real-time
760 or energy-efficiency reasons.
764 endmenu # "RCU Subsystem"
767 tristate "Kernel .config support"
769 This option enables the complete Linux kernel ".config" file
770 contents to be saved in the kernel. It provides documentation
771 of which kernel options are used in a running kernel or in an
772 on-disk kernel. This information can be extracted from the kernel
773 image file with the script scripts/extract-ikconfig and used as
774 input to rebuild the current kernel or to build another kernel.
775 It can also be extracted from a running kernel by reading
776 /proc/config.gz if enabled (below).
779 bool "Enable access to .config through /proc/config.gz"
780 depends on IKCONFIG && PROC_FS
782 This option enables access to the kernel configuration file
783 through /proc/config.gz.
786 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
790 Select kernel log buffer size as a power of 2.
800 # Architectures with an unreliable sched_clock() should select this:
802 config HAVE_UNSTABLE_SCHED_CLOCK
805 config GENERIC_SCHED_CLOCK
809 # For architectures that want to enable the support for NUMA-affine scheduler
812 config ARCH_SUPPORTS_NUMA_BALANCING
816 # For architectures that know their GCC __int128 support is sound
818 config ARCH_SUPPORTS_INT128
821 # For architectures that (ab)use NUMA to represent different memory regions
822 # all cpu-local but of different latencies, such as SuperH.
824 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
828 # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
829 config ARCH_WANTS_PROT_NUMA_PROT_NONE
832 config ARCH_USES_NUMA_PROT_NONE
835 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
836 depends on NUMA_BALANCING
838 config NUMA_BALANCING_DEFAULT_ENABLED
839 bool "Automatically enable NUMA aware memory/task placement"
841 depends on NUMA_BALANCING
843 If set, automatic NUMA balancing will be enabled if running on a NUMA
846 config NUMA_BALANCING
847 bool "Memory placement aware NUMA scheduler"
848 depends on ARCH_SUPPORTS_NUMA_BALANCING
849 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
850 depends on SMP && NUMA && MIGRATION
852 This option adds support for automatic NUMA aware memory/task placement.
853 The mechanism is quite primitive and is based on migrating memory when
854 it has references to the node the task is running on.
856 This system will be inactive on UMA systems.
859 boolean "Control Group support"
862 This option adds support for grouping sets of processes together, for
863 use with process control subsystems such as Cpusets, CFS, memory
864 controls or device isolation.
866 - Documentation/scheduler/sched-design-CFS.txt (CFS)
867 - Documentation/cgroups/ (features for grouping, isolation
868 and resource control)
875 bool "Example debug cgroup subsystem"
878 This option enables a simple cgroup subsystem that
879 exports useful debugging information about the cgroups
884 config CGROUP_FREEZER
885 bool "Freezer cgroup subsystem"
887 Provides a way to freeze and unfreeze all tasks in a
891 bool "Device controller for cgroups"
893 Provides a cgroup implementing whitelists for devices which
894 a process in the cgroup can mknod or open.
897 bool "Cpuset support"
899 This option will let you create and manage CPUSETs which
900 allow dynamically partitioning a system into sets of CPUs and
901 Memory Nodes and assigning tasks to run only within those sets.
902 This is primarily useful on large SMP or NUMA systems.
906 config PROC_PID_CPUSET
907 bool "Include legacy /proc/<pid>/cpuset file"
911 config CGROUP_CPUACCT
912 bool "Simple CPU accounting cgroup subsystem"
914 Provides a simple Resource Controller for monitoring the
915 total CPU consumed by the tasks in a cgroup.
917 config RESOURCE_COUNTERS
918 bool "Resource counters"
920 This option enables controller independent resource accounting
921 infrastructure that works with cgroups.
924 bool "Memory Resource Controller for Control Groups"
925 depends on RESOURCE_COUNTERS
928 Provides a memory resource controller that manages both anonymous
929 memory and page cache. (See Documentation/cgroups/memory.txt)
931 Note that setting this option increases fixed memory overhead
932 associated with each page of memory in the system. By this,
933 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
934 usage tracking struct at boot. Total amount of this is printed out
937 Only enable when you're ok with these trade offs and really
938 sure you need the memory resource controller. Even when you enable
939 this, you can set "cgroup_disable=memory" at your boot option to
940 disable memory resource controller and you can avoid overheads.
941 (and lose benefits of memory resource controller)
943 This config option also selects MM_OWNER config option, which
944 could in turn add some fork/exit overhead.
947 bool "Memory Resource Controller Swap Extension"
948 depends on MEMCG && SWAP
950 Add swap management feature to memory resource controller. When you
951 enable this, you can limit mem+swap usage per cgroup. In other words,
952 when you disable this, memory resource controller has no cares to
953 usage of swap...a process can exhaust all of the swap. This extension
954 is useful when you want to avoid exhaustion swap but this itself
955 adds more overheads and consumes memory for remembering information.
956 Especially if you use 32bit system or small memory system, please
957 be careful about enabling this. When memory resource controller
958 is disabled by boot option, this will be automatically disabled and
959 there will be no overhead from this. Even when you set this config=y,
960 if boot option "swapaccount=0" is set, swap will not be accounted.
961 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
962 size is 4096bytes, 512k per 1Gbytes of swap.
963 config MEMCG_SWAP_ENABLED
964 bool "Memory Resource Controller Swap Extension enabled by default"
965 depends on MEMCG_SWAP
968 Memory Resource Controller Swap Extension comes with its price in
969 a bigger memory consumption. General purpose distribution kernels
970 which want to enable the feature but keep it disabled by default
971 and let the user enable it by swapaccount=1 boot command line
972 parameter should have this option unselected.
973 For those who want to have the feature enabled by default should
974 select this option (if, for some reason, they need to disable it
975 then swapaccount=0 does the trick).
977 bool "Memory Resource Controller Kernel Memory accounting"
979 depends on SLUB || SLAB
981 The Kernel Memory extension for Memory Resource Controller can limit
982 the amount of memory used by kernel objects in the system. Those are
983 fundamentally different from the entities handled by the standard
984 Memory Controller, which are page-based, and can be swapped. Users of
985 the kmem extension can use it to guarantee that no group of processes
986 will ever exhaust kernel resources alone.
988 config CGROUP_HUGETLB
989 bool "HugeTLB Resource Controller for Control Groups"
990 depends on RESOURCE_COUNTERS && HUGETLB_PAGE
993 Provides a cgroup Resource Controller for HugeTLB pages.
994 When you enable this, you can put a per cgroup limit on HugeTLB usage.
995 The limit is enforced during page fault. Since HugeTLB doesn't
996 support page reclaim, enforcing the limit at page fault time implies
997 that, the application will get SIGBUS signal if it tries to access
998 HugeTLB pages beyond its limit. This requires the application to know
999 beforehand how much HugeTLB pages it would require for its use. The
1000 control group is tracked in the third page lru pointer. This means
1001 that we cannot use the controller with huge page less than 3 pages.
1004 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1005 depends on PERF_EVENTS && CGROUPS
1007 This option extends the per-cpu mode to restrict monitoring to
1008 threads which belong to the cgroup specified and run on the
1013 menuconfig CGROUP_SCHED
1014 bool "Group CPU scheduler"
1017 This feature lets CPU scheduler recognize task groups and control CPU
1018 bandwidth allocation to such task groups. It uses cgroups to group
1022 config FAIR_GROUP_SCHED
1023 bool "Group scheduling for SCHED_OTHER"
1024 depends on CGROUP_SCHED
1025 default CGROUP_SCHED
1027 config CFS_BANDWIDTH
1028 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1029 depends on FAIR_GROUP_SCHED
1032 This option allows users to define CPU bandwidth rates (limits) for
1033 tasks running within the fair group scheduler. Groups with no limit
1034 set are considered to be unconstrained and will run with no
1036 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1038 config RT_GROUP_SCHED
1039 bool "Group scheduling for SCHED_RR/FIFO"
1040 depends on CGROUP_SCHED
1043 This feature lets you explicitly allocate real CPU bandwidth
1044 to task groups. If enabled, it will also make it impossible to
1045 schedule realtime tasks for non-root users until you allocate
1046 realtime bandwidth for them.
1047 See Documentation/scheduler/sched-rt-group.txt for more information.
1052 bool "Block IO controller"
1056 Generic block IO controller cgroup interface. This is the common
1057 cgroup interface which should be used by various IO controlling
1060 Currently, CFQ IO scheduler uses it to recognize task groups and
1061 control disk bandwidth allocation (proportional time slice allocation)
1062 to such task groups. It is also used by bio throttling logic in
1063 block layer to implement upper limit in IO rates on a device.
1065 This option only enables generic Block IO controller infrastructure.
1066 One needs to also enable actual IO controlling logic/policy. For
1067 enabling proportional weight division of disk bandwidth in CFQ, set
1068 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1069 CONFIG_BLK_DEV_THROTTLING=y.
1071 See Documentation/cgroups/blkio-controller.txt for more information.
1073 config DEBUG_BLK_CGROUP
1074 bool "Enable Block IO controller debugging"
1075 depends on BLK_CGROUP
1078 Enable some debugging help. Currently it exports additional stat
1079 files in a cgroup which can be useful for debugging.
1083 config CHECKPOINT_RESTORE
1084 bool "Checkpoint/restore support" if EXPERT
1087 Enables additional kernel features in a sake of checkpoint/restore.
1088 In particular it adds auxiliary prctl codes to setup process text,
1089 data and heap segment sizes, and a few additional /proc filesystem
1092 If unsure, say N here.
1094 menuconfig NAMESPACES
1095 bool "Namespaces support" if EXPERT
1098 Provides the way to make tasks work with different objects using
1099 the same id. For example same IPC id may refer to different objects
1100 or same user id or pid may refer to different tasks when used in
1101 different namespaces.
1106 bool "UTS namespace"
1109 In this namespace tasks see different info provided with the
1113 bool "IPC namespace"
1114 depends on (SYSVIPC || POSIX_MQUEUE)
1117 In this namespace tasks work with IPC ids which correspond to
1118 different IPC objects in different namespaces.
1121 bool "User namespace"
1122 select UIDGID_STRICT_TYPE_CHECKS
1126 This allows containers, i.e. vservers, to use user namespaces
1127 to provide different user info for different servers.
1129 When user namespaces are enabled in the kernel it is
1130 recommended that the MEMCG and MEMCG_KMEM options also be
1131 enabled and that user-space use the memory control groups to
1132 limit the amount of memory a memory unprivileged users can
1138 bool "PID Namespaces"
1141 Support process id namespaces. This allows having multiple
1142 processes with the same pid as long as they are in different
1143 pid namespaces. This is a building block of containers.
1146 bool "Network namespace"
1150 Allow user space to create what appear to be multiple instances
1151 of the network stack.
1155 config UIDGID_STRICT_TYPE_CHECKS
1156 bool "Require conversions between uid/gids and their internal representation"
1159 While the nececessary conversions are being added to all subsystems this option allows
1160 the code to continue to build for unconverted subsystems.
1162 Say Y here if you want the strict type checking enabled
1164 config SCHED_AUTOGROUP
1165 bool "Automatic process group scheduling"
1169 select FAIR_GROUP_SCHED
1171 This option optimizes the scheduler for common desktop workloads by
1172 automatically creating and populating task groups. This separation
1173 of workloads isolates aggressive CPU burners (like build jobs) from
1174 desktop applications. Task group autogeneration is currently based
1180 config SYSFS_DEPRECATED
1181 bool "Enable deprecated sysfs features to support old userspace tools"
1185 This option adds code that switches the layout of the "block" class
1186 devices, to not show up in /sys/class/block/, but only in
1189 This switch is only active when the sysfs.deprecated=1 boot option is
1190 passed or the SYSFS_DEPRECATED_V2 option is set.
1192 This option allows new kernels to run on old distributions and tools,
1193 which might get confused by /sys/class/block/. Since 2007/2008 all
1194 major distributions and tools handle this just fine.
1196 Recent distributions and userspace tools after 2009/2010 depend on
1197 the existence of /sys/class/block/, and will not work with this
1200 Only if you are using a new kernel on an old distribution, you might
1203 config SYSFS_DEPRECATED_V2
1204 bool "Enable deprecated sysfs features by default"
1207 depends on SYSFS_DEPRECATED
1209 Enable deprecated sysfs by default.
1211 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1214 Only if you are using a new kernel on an old distribution, you might
1215 need to say Y here. Even then, odds are you would not need it
1216 enabled, you can always pass the boot option if absolutely necessary.
1219 bool "Kernel->user space relay support (formerly relayfs)"
1221 This option enables support for relay interface support in
1222 certain file systems (such as debugfs).
1223 It is designed to provide an efficient mechanism for tools and
1224 facilities to relay large amounts of data from kernel space to
1229 config BLK_DEV_INITRD
1230 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1231 depends on BROKEN || !FRV
1233 The initial RAM filesystem is a ramfs which is loaded by the
1234 boot loader (loadlin or lilo) and that is mounted as root
1235 before the normal boot procedure. It is typically used to
1236 load modules needed to mount the "real" root file system,
1237 etc. See <file:Documentation/initrd.txt> for details.
1239 If RAM disk support (BLK_DEV_RAM) is also included, this
1240 also enables initial RAM disk (initrd) support and adds
1241 15 Kbytes (more on some other architectures) to the kernel size.
1247 source "usr/Kconfig"
1251 config CC_OPTIMIZE_FOR_SIZE
1252 bool "Optimize for size"
1254 Enabling this option will pass "-Os" instead of "-O2" to gcc
1255 resulting in a smaller kernel.
1268 config SYSCTL_EXCEPTION_TRACE
1271 Enable support for /proc/sys/debug/exception-trace.
1273 config SYSCTL_ARCH_UNALIGN_NO_WARN
1276 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1277 Allows arch to define/use @no_unaligned_warning to possibly warn
1278 about unaligned access emulation going on under the hood.
1280 config SYSCTL_ARCH_UNALIGN_ALLOW
1283 Enable support for /proc/sys/kernel/unaligned-trap
1284 Allows arches to define/use @unaligned_enabled to runtime toggle
1285 the unaligned access emulation.
1286 see arch/parisc/kernel/unaligned.c for reference
1288 config HAVE_PCSPKR_PLATFORM
1292 bool "Configure standard kernel features (expert users)"
1293 # Unhide debug options, to make the on-by-default options visible
1296 This option allows certain base kernel options and settings
1297 to be disabled or tweaked. This is for specialized
1298 environments which can tolerate a "non-standard" kernel.
1299 Only use this if you really know what you are doing.
1302 bool "Enable 16-bit UID system calls" if EXPERT
1303 depends on HAVE_UID16
1306 This enables the legacy 16-bit UID syscall wrappers.
1308 config SYSCTL_SYSCALL
1309 bool "Sysctl syscall support" if EXPERT
1310 depends on PROC_SYSCTL
1314 sys_sysctl uses binary paths that have been found challenging
1315 to properly maintain and use. The interface in /proc/sys
1316 using paths with ascii names is now the primary path to this
1319 Almost nothing using the binary sysctl interface so if you are
1320 trying to save some space it is probably safe to disable this,
1321 making your kernel marginally smaller.
1323 If unsure say N here.
1326 bool "Load all symbols for debugging/ksymoops" if EXPERT
1329 Say Y here to let the kernel print out symbolic crash information and
1330 symbolic stack backtraces. This increases the size of the kernel
1331 somewhat, as all symbols have to be loaded into the kernel image.
1334 bool "Include all symbols in kallsyms"
1335 depends on DEBUG_KERNEL && KALLSYMS
1337 Normally kallsyms only contains the symbols of functions for nicer
1338 OOPS messages and backtraces (i.e., symbols from the text and inittext
1339 sections). This is sufficient for most cases. And only in very rare
1340 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1341 names of variables from the data sections, etc).
1343 This option makes sure that all symbols are loaded into the kernel
1344 image (i.e., symbols from all sections) in cost of increased kernel
1345 size (depending on the kernel configuration, it may be 300KiB or
1346 something like this).
1348 Say N unless you really need all symbols.
1352 bool "Enable support for printk" if EXPERT
1355 This option enables normal printk support. Removing it
1356 eliminates most of the message strings from the kernel image
1357 and makes the kernel more or less silent. As this makes it
1358 very difficult to diagnose system problems, saying N here is
1359 strongly discouraged.
1362 bool "BUG() support" if EXPERT
1365 Disabling this option eliminates support for BUG and WARN, reducing
1366 the size of your kernel image and potentially quietly ignoring
1367 numerous fatal conditions. You should only consider disabling this
1368 option for embedded systems with no facilities for reporting errors.
1374 bool "Enable ELF core dumps" if EXPERT
1376 Enable support for generating core dumps. Disabling saves about 4k.
1379 config PCSPKR_PLATFORM
1380 bool "Enable PC-Speaker support" if EXPERT
1381 depends on HAVE_PCSPKR_PLATFORM
1385 This option allows to disable the internal PC-Speaker
1386 support, saving some memory.
1390 bool "Enable full-sized data structures for core" if EXPERT
1392 Disabling this option reduces the size of miscellaneous core
1393 kernel data structures. This saves memory on small machines,
1394 but may reduce performance.
1397 bool "Enable futex support" if EXPERT
1401 Disabling this option will cause the kernel to be built without
1402 support for "fast userspace mutexes". The resulting kernel may not
1403 run glibc-based applications correctly.
1406 bool "Enable eventpoll support" if EXPERT
1410 Disabling this option will cause the kernel to be built without
1411 support for epoll family of system calls.
1414 bool "Enable signalfd() system call" if EXPERT
1418 Enable the signalfd() system call that allows to receive signals
1419 on a file descriptor.
1424 bool "Enable timerfd() system call" if EXPERT
1428 Enable the timerfd() system call that allows to receive timer
1429 events on a file descriptor.
1434 bool "Enable eventfd() system call" if EXPERT
1438 Enable the eventfd() system call that allows to receive both
1439 kernel notification (ie. KAIO) or userspace notifications.
1444 bool "Use full shmem filesystem" if EXPERT
1448 The shmem is an internal filesystem used to manage shared memory.
1449 It is backed by swap and manages resource limits. It is also exported
1450 to userspace as tmpfs if TMPFS is enabled. Disabling this
1451 option replaces shmem and tmpfs with the much simpler ramfs code,
1452 which may be appropriate on small systems without swap.
1455 bool "Enable AIO support" if EXPERT
1458 This option enables POSIX asynchronous I/O which may by used
1459 by some high performance threaded applications. Disabling
1460 this option saves about 7k.
1464 bool "Enable PCI quirk workarounds" if EXPERT
1467 This enables workarounds for various PCI chipset
1468 bugs/quirks. Disable this only if your target machine is
1469 unaffected by PCI quirks.
1472 bool "Embedded system"
1475 This option should be enabled if compiling the kernel for
1476 an embedded system so certain expert options are available
1479 config HAVE_PERF_EVENTS
1482 See tools/perf/design.txt for details.
1484 config PERF_USE_VMALLOC
1487 See tools/perf/design.txt for details
1489 menu "Kernel Performance Events And Counters"
1492 bool "Kernel performance events and counters"
1493 default y if PROFILING
1494 depends on HAVE_PERF_EVENTS
1498 Enable kernel support for various performance events provided
1499 by software and hardware.
1501 Software events are supported either built-in or via the
1502 use of generic tracepoints.
1504 Most modern CPUs support performance events via performance
1505 counter registers. These registers count the number of certain
1506 types of hw events: such as instructions executed, cachemisses
1507 suffered, or branches mis-predicted - without slowing down the
1508 kernel or applications. These registers can also trigger interrupts
1509 when a threshold number of events have passed - and can thus be
1510 used to profile the code that runs on that CPU.
1512 The Linux Performance Event subsystem provides an abstraction of
1513 these software and hardware event capabilities, available via a
1514 system call and used by the "perf" utility in tools/perf/. It
1515 provides per task and per CPU counters, and it provides event
1516 capabilities on top of those.
1520 config DEBUG_PERF_USE_VMALLOC
1522 bool "Debug: use vmalloc to back perf mmap() buffers"
1523 depends on PERF_EVENTS && DEBUG_KERNEL
1524 select PERF_USE_VMALLOC
1526 Use vmalloc memory to back perf mmap() buffers.
1528 Mostly useful for debugging the vmalloc code on platforms
1529 that don't require it.
1535 config VM_EVENT_COUNTERS
1537 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1539 VM event counters are needed for event counts to be shown.
1540 This option allows the disabling of the VM event counters
1541 on EXPERT systems. /proc/vmstat will only show page counts
1542 if VM event counters are disabled.
1546 bool "Enable SLUB debugging support" if EXPERT
1547 depends on SLUB && SYSFS
1549 SLUB has extensive debug support features. Disabling these can
1550 result in significant savings in code size. This also disables
1551 SLUB sysfs support. /sys/slab will not exist and there will be
1552 no support for cache validation etc.
1555 bool "Disable heap randomization"
1558 Randomizing heap placement makes heap exploits harder, but it
1559 also breaks ancient binaries (including anything libc5 based).
1560 This option changes the bootup default to heap randomization
1561 disabled, and can be overridden at runtime by setting
1562 /proc/sys/kernel/randomize_va_space to 2.
1564 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1567 prompt "Choose SLAB allocator"
1570 This option allows to select a slab allocator.
1575 The regular slab allocator that is established and known to work
1576 well in all environments. It organizes cache hot objects in
1577 per cpu and per node queues.
1580 bool "SLUB (Unqueued Allocator)"
1582 SLUB is a slab allocator that minimizes cache line usage
1583 instead of managing queues of cached objects (SLAB approach).
1584 Per cpu caching is realized using slabs of objects instead
1585 of queues of objects. SLUB can use memory efficiently
1586 and has enhanced diagnostics. SLUB is the default choice for
1591 bool "SLOB (Simple Allocator)"
1593 SLOB replaces the stock allocator with a drastically simpler
1594 allocator. SLOB is generally more space efficient but
1595 does not perform as well on large systems.
1599 config SLUB_CPU_PARTIAL
1601 depends on SLUB && SMP
1602 bool "SLUB per cpu partial cache"
1604 Per cpu partial caches accellerate objects allocation and freeing
1605 that is local to a processor at the price of more indeterminism
1606 in the latency of the free. On overflow these caches will be cleared
1607 which requires the taking of locks that may cause latency spikes.
1608 Typically one would choose no for a realtime system.
1610 config MMAP_ALLOW_UNINITIALIZED
1611 bool "Allow mmapped anonymous memory to be uninitialized"
1612 depends on EXPERT && !MMU
1615 Normally, and according to the Linux spec, anonymous memory obtained
1616 from mmap() has it's contents cleared before it is passed to
1617 userspace. Enabling this config option allows you to request that
1618 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1619 providing a huge performance boost. If this option is not enabled,
1620 then the flag will be ignored.
1622 This is taken advantage of by uClibc's malloc(), and also by
1623 ELF-FDPIC binfmt's brk and stack allocator.
1625 Because of the obvious security issues, this option should only be
1626 enabled on embedded devices where you control what is run in
1627 userspace. Since that isn't generally a problem on no-MMU systems,
1628 it is normally safe to say Y here.
1630 See Documentation/nommu-mmap.txt for more information.
1633 bool "Profiling support"
1635 Say Y here to enable the extended profiling support mechanisms used
1636 by profilers such as OProfile.
1639 # Place an empty function call at each tracepoint site. Can be
1640 # dynamically changed for a probe function.
1645 source "arch/Kconfig"
1647 endmenu # General setup
1649 config HAVE_GENERIC_DMA_COHERENT
1656 depends on SLAB || SLUB_DEBUG
1664 default 0 if BASE_FULL
1665 default 1 if !BASE_FULL
1667 config SYSTEM_TRUSTED_KEYRING
1668 bool "Provide system-wide ring of trusted keys"
1671 Provide a system keyring to which trusted keys can be added. Keys in
1672 the keyring are considered to be trusted. Keys may be added at will
1673 by the kernel from compiled-in data and from hardware key stores, but
1674 userspace may only add extra keys if those keys can be verified by
1675 keys already in the keyring.
1677 Keys in this keyring are used by module signature checking.
1680 bool "Enable loadable module support"
1683 Kernel modules are small pieces of compiled code which can
1684 be inserted in the running kernel, rather than being
1685 permanently built into the kernel. You use the "modprobe"
1686 tool to add (and sometimes remove) them. If you say Y here,
1687 many parts of the kernel can be built as modules (by
1688 answering M instead of Y where indicated): this is most
1689 useful for infrequently used options which are not required
1690 for booting. For more information, see the man pages for
1691 modprobe, lsmod, modinfo, insmod and rmmod.
1693 If you say Y here, you will need to run "make
1694 modules_install" to put the modules under /lib/modules/
1695 where modprobe can find them (you may need to be root to do
1702 config MODULE_FORCE_LOAD
1703 bool "Forced module loading"
1706 Allow loading of modules without version information (ie. modprobe
1707 --force). Forced module loading sets the 'F' (forced) taint flag and
1708 is usually a really bad idea.
1710 config MODULE_UNLOAD
1711 bool "Module unloading"
1713 Without this option you will not be able to unload any
1714 modules (note that some modules may not be unloadable
1715 anyway), which makes your kernel smaller, faster
1716 and simpler. If unsure, say Y.
1718 config MODULE_FORCE_UNLOAD
1719 bool "Forced module unloading"
1720 depends on MODULE_UNLOAD
1722 This option allows you to force a module to unload, even if the
1723 kernel believes it is unsafe: the kernel will remove the module
1724 without waiting for anyone to stop using it (using the -f option to
1725 rmmod). This is mainly for kernel developers and desperate users.
1729 bool "Module versioning support"
1731 Usually, you have to use modules compiled with your kernel.
1732 Saying Y here makes it sometimes possible to use modules
1733 compiled for different kernels, by adding enough information
1734 to the modules to (hopefully) spot any changes which would
1735 make them incompatible with the kernel you are running. If
1738 config MODULE_SRCVERSION_ALL
1739 bool "Source checksum for all modules"
1741 Modules which contain a MODULE_VERSION get an extra "srcversion"
1742 field inserted into their modinfo section, which contains a
1743 sum of the source files which made it. This helps maintainers
1744 see exactly which source was used to build a module (since
1745 others sometimes change the module source without updating
1746 the version). With this option, such a "srcversion" field
1747 will be created for all modules. If unsure, say N.
1750 bool "Module signature verification"
1752 select SYSTEM_TRUSTED_KEYRING
1755 select ASYMMETRIC_KEY_TYPE
1756 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1757 select PUBLIC_KEY_ALGO_RSA
1760 select X509_CERTIFICATE_PARSER
1762 Check modules for valid signatures upon load: the signature
1763 is simply appended to the module. For more information see
1764 Documentation/module-signing.txt.
1766 !!!WARNING!!! If you enable this option, you MUST make sure that the
1767 module DOES NOT get stripped after being signed. This includes the
1768 debuginfo strip done by some packagers (such as rpmbuild) and
1769 inclusion into an initramfs that wants the module size reduced.
1771 config MODULE_SIG_FORCE
1772 bool "Require modules to be validly signed"
1773 depends on MODULE_SIG
1775 Reject unsigned modules or signed modules for which we don't have a
1776 key. Without this, such modules will simply taint the kernel.
1778 config MODULE_SIG_ALL
1779 bool "Automatically sign all modules"
1781 depends on MODULE_SIG
1783 Sign all modules during make modules_install. Without this option,
1784 modules must be signed manually, using the scripts/sign-file tool.
1786 comment "Do not forget to sign required modules with scripts/sign-file"
1787 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1790 prompt "Which hash algorithm should modules be signed with?"
1791 depends on MODULE_SIG
1793 This determines which sort of hashing algorithm will be used during
1794 signature generation. This algorithm _must_ be built into the kernel
1795 directly so that signature verification can take place. It is not
1796 possible to load a signed module containing the algorithm to check
1797 the signature on that module.
1799 config MODULE_SIG_SHA1
1800 bool "Sign modules with SHA-1"
1803 config MODULE_SIG_SHA224
1804 bool "Sign modules with SHA-224"
1805 select CRYPTO_SHA256
1807 config MODULE_SIG_SHA256
1808 bool "Sign modules with SHA-256"
1809 select CRYPTO_SHA256
1811 config MODULE_SIG_SHA384
1812 bool "Sign modules with SHA-384"
1813 select CRYPTO_SHA512
1815 config MODULE_SIG_SHA512
1816 bool "Sign modules with SHA-512"
1817 select CRYPTO_SHA512
1821 config MODULE_SIG_HASH
1823 depends on MODULE_SIG
1824 default "sha1" if MODULE_SIG_SHA1
1825 default "sha224" if MODULE_SIG_SHA224
1826 default "sha256" if MODULE_SIG_SHA256
1827 default "sha384" if MODULE_SIG_SHA384
1828 default "sha512" if MODULE_SIG_SHA512
1832 config INIT_ALL_POSSIBLE
1835 Back when each arch used to define their own cpu_online_mask and
1836 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1837 with all 1s, and others with all 0s. When they were centralised,
1838 it was better to provide this option than to break all the archs
1839 and have several arch maintainers pursuing me down dark alleys.
1844 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1846 Need stop_machine() primitive.
1848 source "block/Kconfig"
1850 config PREEMPT_NOTIFIERS
1857 # Can be selected by architectures with broken toolchains
1858 # that get confused by correct const<->read_only section
1860 config BROKEN_RODATA
1866 Build a simple ASN.1 grammar compiler that produces a bytecode output
1867 that can be interpreted by the ASN.1 stream decoder and used to
1868 inform it as to what tags are to be expected in a stream and what
1869 functions to call on what tags.
1871 source "kernel/Kconfig.locks"
projects / cascardo / linux.git / blob