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
116 prompt "Kernel compression mode"
118 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
120 The linux kernel is a kind of self-extracting executable.
121 Several compression algorithms are available, which differ
122 in efficiency, compression and decompression speed.
123 Compression speed is only relevant when building a kernel.
124 Decompression speed is relevant at each boot.
126 If you have any problems with bzip2 or lzma compressed
127 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
128 version of this functionality (bzip2 only), for 2.4, was
129 supplied by Christian Ludwig)
131 High compression options are mostly useful for users, who
132 are low on disk space (embedded systems), but for whom ram
135 If in doubt, select 'gzip'
139 depends on HAVE_KERNEL_GZIP
141 The old and tried gzip compression. It provides a good balance
142 between compression ratio and decompression speed.
146 depends on HAVE_KERNEL_BZIP2
148 Its compression ratio and speed is intermediate.
149 Decompression speed is slowest among the choices. The kernel
150 size is about 10% smaller with bzip2, in comparison to gzip.
151 Bzip2 uses a large amount of memory. For modern kernels you
152 will need at least 8MB RAM or more for booting.
156 depends on HAVE_KERNEL_LZMA
158 This compression algorithm's ratio is best. Decompression speed
159 is between gzip and bzip2. Compression is slowest.
160 The kernel size is about 33% smaller with LZMA in comparison to gzip.
164 depends on HAVE_KERNEL_XZ
166 XZ uses the LZMA2 algorithm and instruction set specific
167 BCJ filters which can improve compression ratio of executable
168 code. The size of the kernel is about 30% smaller with XZ in
169 comparison to gzip. On architectures for which there is a BCJ
170 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
171 will create a few percent smaller kernel than plain LZMA.
173 The speed is about the same as with LZMA: The decompression
174 speed of XZ is better than that of bzip2 but worse than gzip
175 and LZO. Compression is slow.
179 depends on HAVE_KERNEL_LZO
181 Its compression ratio is the poorest among the choices. The kernel
182 size is about 10% bigger than gzip; however its speed
183 (both compression and decompression) is the fastest.
187 config DEFAULT_HOSTNAME
188 string "Default hostname"
191 This option determines the default system hostname before userspace
192 calls sethostname(2). The kernel traditionally uses "(none)" here,
193 but you may wish to use a different default here to make a minimal
194 system more usable with less configuration.
197 bool "Support for paging of anonymous memory (swap)"
198 depends on MMU && BLOCK
201 This option allows you to choose whether you want to have support
202 for so called swap devices or swap files in your kernel that are
203 used to provide more virtual memory than the actual RAM present
204 in your computer. If unsure say Y.
209 Inter Process Communication is a suite of library functions and
210 system calls which let processes (running programs) synchronize and
211 exchange information. It is generally considered to be a good thing,
212 and some programs won't run unless you say Y here. In particular, if
213 you want to run the DOS emulator dosemu under Linux (read the
214 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
215 you'll need to say Y here.
217 You can find documentation about IPC with "info ipc" and also in
218 section 6.4 of the Linux Programmer's Guide, available from
219 <http://www.tldp.org/guides.html>.
221 config SYSVIPC_SYSCTL
228 bool "POSIX Message Queues"
231 POSIX variant of message queues is a part of IPC. In POSIX message
232 queues every message has a priority which decides about succession
233 of receiving it by a process. If you want to compile and run
234 programs written e.g. for Solaris with use of its POSIX message
235 queues (functions mq_*) say Y here.
237 POSIX message queues are visible as a filesystem called 'mqueue'
238 and can be mounted somewhere if you want to do filesystem
239 operations on message queues.
243 config POSIX_MQUEUE_SYSCTL
245 depends on POSIX_MQUEUE
250 bool "open by fhandle syscalls"
253 If you say Y here, a user level program will be able to map
254 file names to handle and then later use the handle for
255 different file system operations. This is useful in implementing
256 userspace file servers, which now track files using handles instead
257 of names. The handle would remain the same even if file names
258 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
262 bool "Auditing support"
265 Enable auditing infrastructure that can be used with another
266 kernel subsystem, such as SELinux (which requires this for
267 logging of avc messages output). Does not do system-call
268 auditing without CONFIG_AUDITSYSCALL.
271 bool "Enable system-call auditing support"
272 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
273 default y if SECURITY_SELINUX
275 Enable low-overhead system-call auditing infrastructure that
276 can be used independently or with another kernel subsystem,
281 depends on AUDITSYSCALL
286 depends on AUDITSYSCALL
289 config AUDIT_LOGINUID_IMMUTABLE
290 bool "Make audit loginuid immutable"
293 The config option toggles if a task setting its loginuid requires
294 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
295 but should instead only allow setting its loginuid if it was never
296 previously set. On systems which use systemd or a similar central
297 process to restart login services this should be set to true. On older
298 systems in which an admin would typically have to directly stop and
299 start processes this should be set to false. Setting this to true allows
300 one to drop potentially dangerous capabilites from the login tasks,
301 but may not be backwards compatible with older init systems.
303 source "kernel/irq/Kconfig"
304 source "kernel/time/Kconfig"
306 menu "CPU/Task time and stats accounting"
308 config VIRT_CPU_ACCOUNTING
312 prompt "Cputime accounting"
313 default TICK_CPU_ACCOUNTING if !PPC64
314 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
316 # Kind of a stub config for the pure tick based cputime accounting
317 config TICK_CPU_ACCOUNTING
318 bool "Simple tick based cputime accounting"
319 depends on !S390 && !NO_HZ_FULL
321 This is the basic tick based cputime accounting that maintains
322 statistics about user, system and idle time spent on per jiffies
327 config VIRT_CPU_ACCOUNTING_NATIVE
328 bool "Deterministic task and CPU time accounting"
329 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
330 select VIRT_CPU_ACCOUNTING
332 Select this option to enable more accurate task and CPU time
333 accounting. This is done by reading a CPU counter on each
334 kernel entry and exit and on transitions within the kernel
335 between system, softirq and hardirq state, so there is a
336 small performance impact. In the case of s390 or IBM POWER > 5,
337 this also enables accounting of stolen time on logically-partitioned
340 config VIRT_CPU_ACCOUNTING_GEN
341 bool "Full dynticks CPU time accounting"
342 depends on HAVE_CONTEXT_TRACKING && 64BIT
343 select VIRT_CPU_ACCOUNTING
344 select CONTEXT_TRACKING
346 Select this option to enable task and CPU time accounting on full
347 dynticks systems. This accounting is implemented by watching every
348 kernel-user boundaries using the context tracking subsystem.
349 The accounting is thus performed at the expense of some significant
352 For now this is only useful if you are working on the full
353 dynticks subsystem development.
357 config IRQ_TIME_ACCOUNTING
358 bool "Fine granularity task level IRQ time accounting"
359 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
361 Select this option to enable fine granularity task irq time
362 accounting. This is done by reading a timestamp on each
363 transitions between softirq and hardirq state, so there can be a
364 small performance impact.
366 If in doubt, say N here.
370 config BSD_PROCESS_ACCT
371 bool "BSD Process Accounting"
373 If you say Y here, a user level program will be able to instruct the
374 kernel (via a special system call) to write process accounting
375 information to a file: whenever a process exits, information about
376 that process will be appended to the file by the kernel. The
377 information includes things such as creation time, owning user,
378 command name, memory usage, controlling terminal etc. (the complete
379 list is in the struct acct in <file:include/linux/acct.h>). It is
380 up to the user level program to do useful things with this
381 information. This is generally a good idea, so say Y.
383 config BSD_PROCESS_ACCT_V3
384 bool "BSD Process Accounting version 3 file format"
385 depends on BSD_PROCESS_ACCT
388 If you say Y here, the process accounting information is written
389 in a new file format that also logs the process IDs of each
390 process and it's parent. Note that this file format is incompatible
391 with previous v0/v1/v2 file formats, so you will need updated tools
392 for processing it. A preliminary version of these tools is available
393 at <http://www.gnu.org/software/acct/>.
396 bool "Export task/process statistics through netlink"
400 Export selected statistics for tasks/processes through the
401 generic netlink interface. Unlike BSD process accounting, the
402 statistics are available during the lifetime of tasks/processes as
403 responses to commands. Like BSD accounting, they are sent to user
408 config TASK_DELAY_ACCT
409 bool "Enable per-task delay accounting"
412 Collect information on time spent by a task waiting for system
413 resources like cpu, synchronous block I/O completion and swapping
414 in pages. Such statistics can help in setting a task's priorities
415 relative to other tasks for cpu, io, rss limits etc.
420 bool "Enable extended accounting over taskstats"
423 Collect extended task accounting data and send the data
424 to userland for processing over the taskstats interface.
428 config TASK_IO_ACCOUNTING
429 bool "Enable per-task storage I/O accounting"
430 depends on TASK_XACCT
432 Collect information on the number of bytes of storage I/O which this
437 endmenu # "CPU/Task time and stats accounting"
442 prompt "RCU Implementation"
446 bool "Tree-based hierarchical RCU"
447 depends on !PREEMPT && SMP
450 This option selects the RCU implementation that is
451 designed for very large SMP system with hundreds or
452 thousands of CPUs. It also scales down nicely to
455 config TREE_PREEMPT_RCU
456 bool "Preemptible tree-based hierarchical RCU"
459 This option selects the RCU implementation that is
460 designed for very large SMP systems with hundreds or
461 thousands of CPUs, but for which real-time response
462 is also required. It also scales down nicely to
465 Select this option if you are unsure.
468 bool "UP-only small-memory-footprint RCU"
469 depends on !PREEMPT && !SMP
471 This option selects the RCU implementation that is
472 designed for UP systems from which real-time response
473 is not required. This option greatly reduces the
474 memory footprint of RCU.
479 def_bool TREE_PREEMPT_RCU
481 This option enables preemptible-RCU code that is common between
482 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
484 config RCU_STALL_COMMON
485 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
487 This option enables RCU CPU stall code that is common between
488 the TINY and TREE variants of RCU. The purpose is to allow
489 the tiny variants to disable RCU CPU stall warnings, while
490 making these warnings mandatory for the tree variants.
492 config CONTEXT_TRACKING
496 bool "Consider userspace as in RCU extended quiescent state"
497 depends on HAVE_CONTEXT_TRACKING && SMP
498 select CONTEXT_TRACKING
500 This option sets hooks on kernel / userspace boundaries and
501 puts RCU in extended quiescent state when the CPU runs in
502 userspace. It means that when a CPU runs in userspace, it is
503 excluded from the global RCU state machine and thus doesn't
504 try to keep the timer tick on for RCU.
506 Unless you want to hack and help the development of the full
507 dynticks mode, you shouldn't enable this option. It also
508 adds unnecessary overhead.
512 config CONTEXT_TRACKING_FORCE
513 bool "Force context tracking"
514 depends on CONTEXT_TRACKING
515 default CONTEXT_TRACKING
517 Probe on user/kernel boundaries by default in order to
518 test the features that rely on it such as userspace RCU extended
520 This test is there for debugging until we have a real user like the
524 int "Tree-based hierarchical RCU fanout value"
527 depends on TREE_RCU || TREE_PREEMPT_RCU
531 This option controls the fanout of hierarchical implementations
532 of RCU, allowing RCU to work efficiently on machines with
533 large numbers of CPUs. This value must be at least the fourth
534 root of NR_CPUS, which allows NR_CPUS to be insanely large.
535 The default value of RCU_FANOUT should be used for production
536 systems, but if you are stress-testing the RCU implementation
537 itself, small RCU_FANOUT values allow you to test large-system
538 code paths on small(er) systems.
540 Select a specific number if testing RCU itself.
541 Take the default if unsure.
543 config RCU_FANOUT_LEAF
544 int "Tree-based hierarchical RCU leaf-level fanout value"
545 range 2 RCU_FANOUT if 64BIT
546 range 2 RCU_FANOUT if !64BIT
547 depends on TREE_RCU || TREE_PREEMPT_RCU
550 This option controls the leaf-level fanout of hierarchical
551 implementations of RCU, and allows trading off cache misses
552 against lock contention. Systems that synchronize their
553 scheduling-clock interrupts for energy-efficiency reasons will
554 want the default because the smaller leaf-level fanout keeps
555 lock contention levels acceptably low. Very large systems
556 (hundreds or thousands of CPUs) will instead want to set this
557 value to the maximum value possible in order to reduce the
558 number of cache misses incurred during RCU's grace-period
559 initialization. These systems tend to run CPU-bound, and thus
560 are not helped by synchronized interrupts, and thus tend to
561 skew them, which reduces lock contention enough that large
562 leaf-level fanouts work well.
564 Select a specific number if testing RCU itself.
566 Select the maximum permissible value for large systems.
568 Take the default if unsure.
570 config RCU_FANOUT_EXACT
571 bool "Disable tree-based hierarchical RCU auto-balancing"
572 depends on TREE_RCU || TREE_PREEMPT_RCU
575 This option forces use of the exact RCU_FANOUT value specified,
576 regardless of imbalances in the hierarchy. This is useful for
577 testing RCU itself, and might one day be useful on systems with
578 strong NUMA behavior.
580 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
584 config RCU_FAST_NO_HZ
585 bool "Accelerate last non-dyntick-idle CPU's grace periods"
586 depends on NO_HZ_COMMON && SMP
589 This option permits CPUs to enter dynticks-idle state even if
590 they have RCU callbacks queued, and prevents RCU from waking
591 these CPUs up more than roughly once every four jiffies (by
592 default, you can adjust this using the rcutree.rcu_idle_gp_delay
593 parameter), thus improving energy efficiency. On the other
594 hand, this option increases the duration of RCU grace periods,
595 for example, slowing down synchronize_rcu().
597 Say Y if energy efficiency is critically important, and you
598 don't care about increased grace-period durations.
600 Say N if you are unsure.
602 config TREE_RCU_TRACE
603 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
606 This option provides tracing for the TREE_RCU and
607 TREE_PREEMPT_RCU implementations, permitting Makefile to
608 trivially select kernel/rcutree_trace.c.
611 bool "Enable RCU priority boosting"
612 depends on RT_MUTEXES && PREEMPT_RCU
615 This option boosts the priority of preempted RCU readers that
616 block the current preemptible RCU grace period for too long.
617 This option also prevents heavy loads from blocking RCU
618 callback invocation for all flavors of RCU.
620 Say Y here if you are working with real-time apps or heavy loads
621 Say N here if you are unsure.
623 config RCU_BOOST_PRIO
624 int "Real-time priority to boost RCU readers to"
629 This option specifies the real-time priority to which long-term
630 preempted RCU readers are to be boosted. If you are working
631 with a real-time application that has one or more CPU-bound
632 threads running at a real-time priority level, you should set
633 RCU_BOOST_PRIO to a priority higher then the highest-priority
634 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
635 of 1 is appropriate in the common case, which is real-time
636 applications that do not have any CPU-bound threads.
638 Some real-time applications might not have a single real-time
639 thread that saturates a given CPU, but instead might have
640 multiple real-time threads that, taken together, fully utilize
641 that CPU. In this case, you should set RCU_BOOST_PRIO to
642 a priority higher than the lowest-priority thread that is
643 conspiring to prevent the CPU from running any non-real-time
644 tasks. For example, if one thread at priority 10 and another
645 thread at priority 5 are between themselves fully consuming
646 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
647 set to priority 6 or higher.
649 Specify the real-time priority, or take the default if unsure.
651 config RCU_BOOST_DELAY
652 int "Milliseconds to delay boosting after RCU grace-period start"
657 This option specifies the time to wait after the beginning of
658 a given grace period before priority-boosting preempted RCU
659 readers blocking that grace period. Note that any RCU reader
660 blocking an expedited RCU grace period is boosted immediately.
662 Accept the default if unsure.
665 bool "Offload RCU callback processing from boot-selected CPUs"
666 depends on TREE_RCU || TREE_PREEMPT_RCU
669 Use this option to reduce OS jitter for aggressive HPC or
670 real-time workloads. It can also be used to offload RCU
671 callback invocation to energy-efficient CPUs in battery-powered
672 asymmetric multiprocessors.
674 This option offloads callback invocation from the set of
675 CPUs specified at boot time by the rcu_nocbs parameter.
676 For each such CPU, a kthread ("rcuox/N") will be created to
677 invoke callbacks, where the "N" is the CPU being offloaded,
678 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
679 "s" for RCU-sched. Nothing prevents this kthread from running
680 on the specified CPUs, but (1) the kthreads may be preempted
681 between each callback, and (2) affinity or cgroups can be used
682 to force the kthreads to run on whatever set of CPUs is desired.
684 Say Y here if you want to help to debug reduced OS jitter.
685 Say N here if you are unsure.
688 prompt "Build-forced no-CBs CPUs"
689 default RCU_NOCB_CPU_NONE
691 This option allows no-CBs CPUs (whose RCU callbacks are invoked
692 from kthreads rather than from softirq context) to be specified
693 at build time. Additional no-CBs CPUs may be specified by
694 the rcu_nocbs= boot parameter.
696 config RCU_NOCB_CPU_NONE
697 bool "No build_forced no-CBs CPUs"
698 depends on RCU_NOCB_CPU && !NO_HZ_FULL
700 This option does not force any of the CPUs to be no-CBs CPUs.
701 Only CPUs designated by the rcu_nocbs= boot parameter will be
702 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
703 kthreads whose names begin with "rcuo". All other CPUs will
704 invoke their own RCU callbacks in softirq context.
706 Select this option if you want to choose no-CBs CPUs at
707 boot time, for example, to allow testing of different no-CBs
708 configurations without having to rebuild the kernel each time.
710 config RCU_NOCB_CPU_ZERO
711 bool "CPU 0 is a build_forced no-CBs CPU"
712 depends on RCU_NOCB_CPU && !NO_HZ_FULL
714 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
715 callbacks are invoked by a per-CPU kthread whose name begins
716 with "rcuo". Additional CPUs may be designated as no-CBs
717 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
718 All other CPUs will invoke their own RCU callbacks in softirq
721 Select this if CPU 0 needs to be a no-CBs CPU for real-time
722 or energy-efficiency reasons, but the real reason it exists
723 is to ensure that randconfig testing covers mixed systems.
725 config RCU_NOCB_CPU_ALL
726 bool "All CPUs are build_forced no-CBs CPUs"
727 depends on RCU_NOCB_CPU
729 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
730 boot parameter will be ignored. All CPUs' RCU callbacks will
731 be executed in the context of per-CPU rcuo kthreads created for
732 this purpose. Assuming that the kthreads whose names start with
733 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
734 on the remaining CPUs, but might decrease memory locality during
735 RCU-callback invocation, thus potentially degrading throughput.
737 Select this if all CPUs need to be no-CBs CPUs for real-time
738 or energy-efficiency reasons.
742 endmenu # "RCU Subsystem"
745 tristate "Kernel .config support"
747 This option enables the complete Linux kernel ".config" file
748 contents to be saved in the kernel. It provides documentation
749 of which kernel options are used in a running kernel or in an
750 on-disk kernel. This information can be extracted from the kernel
751 image file with the script scripts/extract-ikconfig and used as
752 input to rebuild the current kernel or to build another kernel.
753 It can also be extracted from a running kernel by reading
754 /proc/config.gz if enabled (below).
757 bool "Enable access to .config through /proc/config.gz"
758 depends on IKCONFIG && PROC_FS
760 This option enables access to the kernel configuration file
761 through /proc/config.gz.
764 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
768 Select kernel log buffer size as a power of 2.
778 # Architectures with an unreliable sched_clock() should select this:
780 config HAVE_UNSTABLE_SCHED_CLOCK
784 # For architectures that want to enable the support for NUMA-affine scheduler
787 config ARCH_SUPPORTS_NUMA_BALANCING
790 # For architectures that (ab)use NUMA to represent different memory regions
791 # all cpu-local but of different latencies, such as SuperH.
793 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
797 # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
798 config ARCH_WANTS_PROT_NUMA_PROT_NONE
801 config ARCH_USES_NUMA_PROT_NONE
804 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
805 depends on NUMA_BALANCING
807 config NUMA_BALANCING_DEFAULT_ENABLED
808 bool "Automatically enable NUMA aware memory/task placement"
810 depends on NUMA_BALANCING
812 If set, autonumic NUMA balancing will be enabled if running on a NUMA
815 config NUMA_BALANCING
816 bool "Memory placement aware NUMA scheduler"
817 depends on ARCH_SUPPORTS_NUMA_BALANCING
818 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
819 depends on SMP && NUMA && MIGRATION
821 This option adds support for automatic NUMA aware memory/task placement.
822 The mechanism is quite primitive and is based on migrating memory when
823 it is references to the node the task is running on.
825 This system will be inactive on UMA systems.
828 boolean "Control Group support"
831 This option adds support for grouping sets of processes together, for
832 use with process control subsystems such as Cpusets, CFS, memory
833 controls or device isolation.
835 - Documentation/scheduler/sched-design-CFS.txt (CFS)
836 - Documentation/cgroups/ (features for grouping, isolation
837 and resource control)
844 bool "Example debug cgroup subsystem"
847 This option enables a simple cgroup subsystem that
848 exports useful debugging information about the cgroups
853 config CGROUP_FREEZER
854 bool "Freezer cgroup subsystem"
856 Provides a way to freeze and unfreeze all tasks in a
860 bool "Device controller for cgroups"
862 Provides a cgroup implementing whitelists for devices which
863 a process in the cgroup can mknod or open.
866 bool "Cpuset support"
868 This option will let you create and manage CPUSETs which
869 allow dynamically partitioning a system into sets of CPUs and
870 Memory Nodes and assigning tasks to run only within those sets.
871 This is primarily useful on large SMP or NUMA systems.
875 config PROC_PID_CPUSET
876 bool "Include legacy /proc/<pid>/cpuset file"
880 config CGROUP_CPUACCT
881 bool "Simple CPU accounting cgroup subsystem"
883 Provides a simple Resource Controller for monitoring the
884 total CPU consumed by the tasks in a cgroup.
886 config RESOURCE_COUNTERS
887 bool "Resource counters"
889 This option enables controller independent resource accounting
890 infrastructure that works with cgroups.
893 bool "Memory Resource Controller for Control Groups"
894 depends on RESOURCE_COUNTERS
897 Provides a memory resource controller that manages both anonymous
898 memory and page cache. (See Documentation/cgroups/memory.txt)
900 Note that setting this option increases fixed memory overhead
901 associated with each page of memory in the system. By this,
902 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
903 usage tracking struct at boot. Total amount of this is printed out
906 Only enable when you're ok with these trade offs and really
907 sure you need the memory resource controller. Even when you enable
908 this, you can set "cgroup_disable=memory" at your boot option to
909 disable memory resource controller and you can avoid overheads.
910 (and lose benefits of memory resource controller)
912 This config option also selects MM_OWNER config option, which
913 could in turn add some fork/exit overhead.
916 bool "Memory Resource Controller Swap Extension"
917 depends on MEMCG && SWAP
919 Add swap management feature to memory resource controller. When you
920 enable this, you can limit mem+swap usage per cgroup. In other words,
921 when you disable this, memory resource controller has no cares to
922 usage of swap...a process can exhaust all of the swap. This extension
923 is useful when you want to avoid exhaustion swap but this itself
924 adds more overheads and consumes memory for remembering information.
925 Especially if you use 32bit system or small memory system, please
926 be careful about enabling this. When memory resource controller
927 is disabled by boot option, this will be automatically disabled and
928 there will be no overhead from this. Even when you set this config=y,
929 if boot option "swapaccount=0" is set, swap will not be accounted.
930 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
931 size is 4096bytes, 512k per 1Gbytes of swap.
932 config MEMCG_SWAP_ENABLED
933 bool "Memory Resource Controller Swap Extension enabled by default"
934 depends on MEMCG_SWAP
937 Memory Resource Controller Swap Extension comes with its price in
938 a bigger memory consumption. General purpose distribution kernels
939 which want to enable the feature but keep it disabled by default
940 and let the user enable it by swapaccount boot command line
941 parameter should have this option unselected.
942 For those who want to have the feature enabled by default should
943 select this option (if, for some reason, they need to disable it
944 then swapaccount=0 does the trick).
946 bool "Memory Resource Controller Kernel Memory accounting"
948 depends on SLUB || SLAB
950 The Kernel Memory extension for Memory Resource Controller can limit
951 the amount of memory used by kernel objects in the system. Those are
952 fundamentally different from the entities handled by the standard
953 Memory Controller, which are page-based, and can be swapped. Users of
954 the kmem extension can use it to guarantee that no group of processes
955 will ever exhaust kernel resources alone.
957 config CGROUP_HUGETLB
958 bool "HugeTLB Resource Controller for Control Groups"
959 depends on RESOURCE_COUNTERS && HUGETLB_PAGE
962 Provides a cgroup Resource Controller for HugeTLB pages.
963 When you enable this, you can put a per cgroup limit on HugeTLB usage.
964 The limit is enforced during page fault. Since HugeTLB doesn't
965 support page reclaim, enforcing the limit at page fault time implies
966 that, the application will get SIGBUS signal if it tries to access
967 HugeTLB pages beyond its limit. This requires the application to know
968 beforehand how much HugeTLB pages it would require for its use. The
969 control group is tracked in the third page lru pointer. This means
970 that we cannot use the controller with huge page less than 3 pages.
973 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
974 depends on PERF_EVENTS && CGROUPS
976 This option extends the per-cpu mode to restrict monitoring to
977 threads which belong to the cgroup specified and run on the
982 menuconfig CGROUP_SCHED
983 bool "Group CPU scheduler"
986 This feature lets CPU scheduler recognize task groups and control CPU
987 bandwidth allocation to such task groups. It uses cgroups to group
991 config FAIR_GROUP_SCHED
992 bool "Group scheduling for SCHED_OTHER"
993 depends on CGROUP_SCHED
997 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
998 depends on FAIR_GROUP_SCHED
1001 This option allows users to define CPU bandwidth rates (limits) for
1002 tasks running within the fair group scheduler. Groups with no limit
1003 set are considered to be unconstrained and will run with no
1005 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1007 config RT_GROUP_SCHED
1008 bool "Group scheduling for SCHED_RR/FIFO"
1009 depends on CGROUP_SCHED
1012 This feature lets you explicitly allocate real CPU bandwidth
1013 to task groups. If enabled, it will also make it impossible to
1014 schedule realtime tasks for non-root users until you allocate
1015 realtime bandwidth for them.
1016 See Documentation/scheduler/sched-rt-group.txt for more information.
1021 bool "Block IO controller"
1025 Generic block IO controller cgroup interface. This is the common
1026 cgroup interface which should be used by various IO controlling
1029 Currently, CFQ IO scheduler uses it to recognize task groups and
1030 control disk bandwidth allocation (proportional time slice allocation)
1031 to such task groups. It is also used by bio throttling logic in
1032 block layer to implement upper limit in IO rates on a device.
1034 This option only enables generic Block IO controller infrastructure.
1035 One needs to also enable actual IO controlling logic/policy. For
1036 enabling proportional weight division of disk bandwidth in CFQ, set
1037 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1038 CONFIG_BLK_DEV_THROTTLING=y.
1040 See Documentation/cgroups/blkio-controller.txt for more information.
1042 config DEBUG_BLK_CGROUP
1043 bool "Enable Block IO controller debugging"
1044 depends on BLK_CGROUP
1047 Enable some debugging help. Currently it exports additional stat
1048 files in a cgroup which can be useful for debugging.
1052 config CHECKPOINT_RESTORE
1053 bool "Checkpoint/restore support" if EXPERT
1056 Enables additional kernel features in a sake of checkpoint/restore.
1057 In particular it adds auxiliary prctl codes to setup process text,
1058 data and heap segment sizes, and a few additional /proc filesystem
1061 If unsure, say N here.
1063 menuconfig NAMESPACES
1064 bool "Namespaces support" if EXPERT
1067 Provides the way to make tasks work with different objects using
1068 the same id. For example same IPC id may refer to different objects
1069 or same user id or pid may refer to different tasks when used in
1070 different namespaces.
1075 bool "UTS namespace"
1078 In this namespace tasks see different info provided with the
1082 bool "IPC namespace"
1083 depends on (SYSVIPC || POSIX_MQUEUE)
1086 In this namespace tasks work with IPC ids which correspond to
1087 different IPC objects in different namespaces.
1090 bool "User namespace"
1091 depends on UIDGID_CONVERTED
1092 select UIDGID_STRICT_TYPE_CHECKS
1096 This allows containers, i.e. vservers, to use user namespaces
1097 to provide different user info for different servers.
1099 When user namespaces are enabled in the kernel it is
1100 recommended that the MEMCG and MEMCG_KMEM options also be
1101 enabled and that user-space use the memory control groups to
1102 limit the amount of memory a memory unprivileged users can
1108 bool "PID Namespaces"
1111 Support process id namespaces. This allows having multiple
1112 processes with the same pid as long as they are in different
1113 pid namespaces. This is a building block of containers.
1116 bool "Network namespace"
1120 Allow user space to create what appear to be multiple instances
1121 of the network stack.
1125 config UIDGID_CONVERTED
1126 # True if all of the selected software conmponents are known
1127 # to have uid_t and gid_t converted to kuid_t and kgid_t
1128 # where appropriate and are otherwise safe to use with
1129 # the user namespace.
1134 depends on XFS_FS = n
1136 config UIDGID_STRICT_TYPE_CHECKS
1137 bool "Require conversions between uid/gids and their internal representation"
1138 depends on UIDGID_CONVERTED
1141 While the nececessary conversions are being added to all subsystems this option allows
1142 the code to continue to build for unconverted subsystems.
1144 Say Y here if you want the strict type checking enabled
1146 config SCHED_AUTOGROUP
1147 bool "Automatic process group scheduling"
1151 select FAIR_GROUP_SCHED
1153 This option optimizes the scheduler for common desktop workloads by
1154 automatically creating and populating task groups. This separation
1155 of workloads isolates aggressive CPU burners (like build jobs) from
1156 desktop applications. Task group autogeneration is currently based
1162 config SYSFS_DEPRECATED
1163 bool "Enable deprecated sysfs features to support old userspace tools"
1167 This option adds code that switches the layout of the "block" class
1168 devices, to not show up in /sys/class/block/, but only in
1171 This switch is only active when the sysfs.deprecated=1 boot option is
1172 passed or the SYSFS_DEPRECATED_V2 option is set.
1174 This option allows new kernels to run on old distributions and tools,
1175 which might get confused by /sys/class/block/. Since 2007/2008 all
1176 major distributions and tools handle this just fine.
1178 Recent distributions and userspace tools after 2009/2010 depend on
1179 the existence of /sys/class/block/, and will not work with this
1182 Only if you are using a new kernel on an old distribution, you might
1185 config SYSFS_DEPRECATED_V2
1186 bool "Enable deprecated sysfs features by default"
1189 depends on SYSFS_DEPRECATED
1191 Enable deprecated sysfs by default.
1193 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1196 Only if you are using a new kernel on an old distribution, you might
1197 need to say Y here. Even then, odds are you would not need it
1198 enabled, you can always pass the boot option if absolutely necessary.
1201 bool "Kernel->user space relay support (formerly relayfs)"
1203 This option enables support for relay interface support in
1204 certain file systems (such as debugfs).
1205 It is designed to provide an efficient mechanism for tools and
1206 facilities to relay large amounts of data from kernel space to
1211 config BLK_DEV_INITRD
1212 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1213 depends on BROKEN || !FRV
1215 The initial RAM filesystem is a ramfs which is loaded by the
1216 boot loader (loadlin or lilo) and that is mounted as root
1217 before the normal boot procedure. It is typically used to
1218 load modules needed to mount the "real" root file system,
1219 etc. See <file:Documentation/initrd.txt> for details.
1221 If RAM disk support (BLK_DEV_RAM) is also included, this
1222 also enables initial RAM disk (initrd) support and adds
1223 15 Kbytes (more on some other architectures) to the kernel size.
1229 source "usr/Kconfig"
1233 config CC_OPTIMIZE_FOR_SIZE
1234 bool "Optimize for size"
1236 Enabling this option will pass "-Os" instead of "-O2" to gcc
1237 resulting in a smaller kernel.
1250 config SYSCTL_EXCEPTION_TRACE
1253 Enable support for /proc/sys/debug/exception-trace.
1255 config SYSCTL_ARCH_UNALIGN_NO_WARN
1258 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1259 Allows arch to define/use @no_unaligned_warning to possibly warn
1260 about unaligned access emulation going on under the hood.
1262 config SYSCTL_ARCH_UNALIGN_ALLOW
1265 Enable support for /proc/sys/kernel/unaligned-trap
1266 Allows arches to define/use @unaligned_enabled to runtime toggle
1267 the unaligned access emulation.
1268 see arch/parisc/kernel/unaligned.c for reference
1270 config HAVE_PCSPKR_PLATFORM
1274 bool "Configure standard kernel features (expert users)"
1275 # Unhide debug options, to make the on-by-default options visible
1278 This option allows certain base kernel options and settings
1279 to be disabled or tweaked. This is for specialized
1280 environments which can tolerate a "non-standard" kernel.
1281 Only use this if you really know what you are doing.
1284 bool "Enable 16-bit UID system calls" if EXPERT
1285 depends on HAVE_UID16
1288 This enables the legacy 16-bit UID syscall wrappers.
1290 config SYSCTL_SYSCALL
1291 bool "Sysctl syscall support" if EXPERT
1292 depends on PROC_SYSCTL
1296 sys_sysctl uses binary paths that have been found challenging
1297 to properly maintain and use. The interface in /proc/sys
1298 using paths with ascii names is now the primary path to this
1301 Almost nothing using the binary sysctl interface so if you are
1302 trying to save some space it is probably safe to disable this,
1303 making your kernel marginally smaller.
1305 If unsure say N here.
1308 bool "Load all symbols for debugging/ksymoops" if EXPERT
1311 Say Y here to let the kernel print out symbolic crash information and
1312 symbolic stack backtraces. This increases the size of the kernel
1313 somewhat, as all symbols have to be loaded into the kernel image.
1316 bool "Include all symbols in kallsyms"
1317 depends on DEBUG_KERNEL && KALLSYMS
1319 Normally kallsyms only contains the symbols of functions for nicer
1320 OOPS messages and backtraces (i.e., symbols from the text and inittext
1321 sections). This is sufficient for most cases. And only in very rare
1322 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1323 names of variables from the data sections, etc).
1325 This option makes sure that all symbols are loaded into the kernel
1326 image (i.e., symbols from all sections) in cost of increased kernel
1327 size (depending on the kernel configuration, it may be 300KiB or
1328 something like this).
1330 Say N unless you really need all symbols.
1334 bool "Enable support for printk" if EXPERT
1337 This option enables normal printk support. Removing it
1338 eliminates most of the message strings from the kernel image
1339 and makes the kernel more or less silent. As this makes it
1340 very difficult to diagnose system problems, saying N here is
1341 strongly discouraged.
1344 bool "BUG() support" if EXPERT
1347 Disabling this option eliminates support for BUG and WARN, reducing
1348 the size of your kernel image and potentially quietly ignoring
1349 numerous fatal conditions. You should only consider disabling this
1350 option for embedded systems with no facilities for reporting errors.
1356 bool "Enable ELF core dumps" if EXPERT
1358 Enable support for generating core dumps. Disabling saves about 4k.
1361 config PCSPKR_PLATFORM
1362 bool "Enable PC-Speaker support" if EXPERT
1363 depends on HAVE_PCSPKR_PLATFORM
1367 This option allows to disable the internal PC-Speaker
1368 support, saving some memory.
1372 bool "Enable full-sized data structures for core" if EXPERT
1374 Disabling this option reduces the size of miscellaneous core
1375 kernel data structures. This saves memory on small machines,
1376 but may reduce performance.
1379 bool "Enable futex support" if EXPERT
1383 Disabling this option will cause the kernel to be built without
1384 support for "fast userspace mutexes". The resulting kernel may not
1385 run glibc-based applications correctly.
1388 bool "Enable eventpoll support" if EXPERT
1392 Disabling this option will cause the kernel to be built without
1393 support for epoll family of system calls.
1396 bool "Enable signalfd() system call" if EXPERT
1400 Enable the signalfd() system call that allows to receive signals
1401 on a file descriptor.
1406 bool "Enable timerfd() system call" if EXPERT
1410 Enable the timerfd() system call that allows to receive timer
1411 events on a file descriptor.
1416 bool "Enable eventfd() system call" if EXPERT
1420 Enable the eventfd() system call that allows to receive both
1421 kernel notification (ie. KAIO) or userspace notifications.
1426 bool "Use full shmem filesystem" if EXPERT
1430 The shmem is an internal filesystem used to manage shared memory.
1431 It is backed by swap and manages resource limits. It is also exported
1432 to userspace as tmpfs if TMPFS is enabled. Disabling this
1433 option replaces shmem and tmpfs with the much simpler ramfs code,
1434 which may be appropriate on small systems without swap.
1437 bool "Enable AIO support" if EXPERT
1440 This option enables POSIX asynchronous I/O which may by used
1441 by some high performance threaded applications. Disabling
1442 this option saves about 7k.
1446 bool "Enable PCI quirk workarounds" if EXPERT
1449 This enables workarounds for various PCI chipset
1450 bugs/quirks. Disable this only if your target machine is
1451 unaffected by PCI quirks.
1454 bool "Embedded system"
1457 This option should be enabled if compiling the kernel for
1458 an embedded system so certain expert options are available
1461 config HAVE_PERF_EVENTS
1464 See tools/perf/design.txt for details.
1466 config PERF_USE_VMALLOC
1469 See tools/perf/design.txt for details
1471 menu "Kernel Performance Events And Counters"
1474 bool "Kernel performance events and counters"
1475 default y if PROFILING
1476 depends on HAVE_PERF_EVENTS
1480 Enable kernel support for various performance events provided
1481 by software and hardware.
1483 Software events are supported either built-in or via the
1484 use of generic tracepoints.
1486 Most modern CPUs support performance events via performance
1487 counter registers. These registers count the number of certain
1488 types of hw events: such as instructions executed, cachemisses
1489 suffered, or branches mis-predicted - without slowing down the
1490 kernel or applications. These registers can also trigger interrupts
1491 when a threshold number of events have passed - and can thus be
1492 used to profile the code that runs on that CPU.
1494 The Linux Performance Event subsystem provides an abstraction of
1495 these software and hardware event capabilities, available via a
1496 system call and used by the "perf" utility in tools/perf/. It
1497 provides per task and per CPU counters, and it provides event
1498 capabilities on top of those.
1502 config DEBUG_PERF_USE_VMALLOC
1504 bool "Debug: use vmalloc to back perf mmap() buffers"
1505 depends on PERF_EVENTS && DEBUG_KERNEL
1506 select PERF_USE_VMALLOC
1508 Use vmalloc memory to back perf mmap() buffers.
1510 Mostly useful for debugging the vmalloc code on platforms
1511 that don't require it.
1517 config VM_EVENT_COUNTERS
1519 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1521 VM event counters are needed for event counts to be shown.
1522 This option allows the disabling of the VM event counters
1523 on EXPERT systems. /proc/vmstat will only show page counts
1524 if VM event counters are disabled.
1528 bool "Enable SLUB debugging support" if EXPERT
1529 depends on SLUB && SYSFS
1531 SLUB has extensive debug support features. Disabling these can
1532 result in significant savings in code size. This also disables
1533 SLUB sysfs support. /sys/slab will not exist and there will be
1534 no support for cache validation etc.
1537 bool "Disable heap randomization"
1540 Randomizing heap placement makes heap exploits harder, but it
1541 also breaks ancient binaries (including anything libc5 based).
1542 This option changes the bootup default to heap randomization
1543 disabled, and can be overridden at runtime by setting
1544 /proc/sys/kernel/randomize_va_space to 2.
1546 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1549 prompt "Choose SLAB allocator"
1552 This option allows to select a slab allocator.
1557 The regular slab allocator that is established and known to work
1558 well in all environments. It organizes cache hot objects in
1559 per cpu and per node queues.
1562 bool "SLUB (Unqueued Allocator)"
1564 SLUB is a slab allocator that minimizes cache line usage
1565 instead of managing queues of cached objects (SLAB approach).
1566 Per cpu caching is realized using slabs of objects instead
1567 of queues of objects. SLUB can use memory efficiently
1568 and has enhanced diagnostics. SLUB is the default choice for
1573 bool "SLOB (Simple Allocator)"
1575 SLOB replaces the stock allocator with a drastically simpler
1576 allocator. SLOB is generally more space efficient but
1577 does not perform as well on large systems.
1581 config MMAP_ALLOW_UNINITIALIZED
1582 bool "Allow mmapped anonymous memory to be uninitialized"
1583 depends on EXPERT && !MMU
1586 Normally, and according to the Linux spec, anonymous memory obtained
1587 from mmap() has it's contents cleared before it is passed to
1588 userspace. Enabling this config option allows you to request that
1589 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1590 providing a huge performance boost. If this option is not enabled,
1591 then the flag will be ignored.
1593 This is taken advantage of by uClibc's malloc(), and also by
1594 ELF-FDPIC binfmt's brk and stack allocator.
1596 Because of the obvious security issues, this option should only be
1597 enabled on embedded devices where you control what is run in
1598 userspace. Since that isn't generally a problem on no-MMU systems,
1599 it is normally safe to say Y here.
1601 See Documentation/nommu-mmap.txt for more information.
1604 bool "Profiling support"
1606 Say Y here to enable the extended profiling support mechanisms used
1607 by profilers such as OProfile.
1610 # Place an empty function call at each tracepoint site. Can be
1611 # dynamically changed for a probe function.
1616 source "arch/Kconfig"
1618 endmenu # General setup
1620 config HAVE_GENERIC_DMA_COHERENT
1627 depends on SLAB || SLUB_DEBUG
1635 default 0 if BASE_FULL
1636 default 1 if !BASE_FULL
1639 bool "Enable loadable module support"
1641 Kernel modules are small pieces of compiled code which can
1642 be inserted in the running kernel, rather than being
1643 permanently built into the kernel. You use the "modprobe"
1644 tool to add (and sometimes remove) them. If you say Y here,
1645 many parts of the kernel can be built as modules (by
1646 answering M instead of Y where indicated): this is most
1647 useful for infrequently used options which are not required
1648 for booting. For more information, see the man pages for
1649 modprobe, lsmod, modinfo, insmod and rmmod.
1651 If you say Y here, you will need to run "make
1652 modules_install" to put the modules under /lib/modules/
1653 where modprobe can find them (you may need to be root to do
1660 config MODULE_FORCE_LOAD
1661 bool "Forced module loading"
1664 Allow loading of modules without version information (ie. modprobe
1665 --force). Forced module loading sets the 'F' (forced) taint flag and
1666 is usually a really bad idea.
1668 config MODULE_UNLOAD
1669 bool "Module unloading"
1671 Without this option you will not be able to unload any
1672 modules (note that some modules may not be unloadable
1673 anyway), which makes your kernel smaller, faster
1674 and simpler. If unsure, say Y.
1676 config MODULE_FORCE_UNLOAD
1677 bool "Forced module unloading"
1678 depends on MODULE_UNLOAD
1680 This option allows you to force a module to unload, even if the
1681 kernel believes it is unsafe: the kernel will remove the module
1682 without waiting for anyone to stop using it (using the -f option to
1683 rmmod). This is mainly for kernel developers and desperate users.
1687 bool "Module versioning support"
1689 Usually, you have to use modules compiled with your kernel.
1690 Saying Y here makes it sometimes possible to use modules
1691 compiled for different kernels, by adding enough information
1692 to the modules to (hopefully) spot any changes which would
1693 make them incompatible with the kernel you are running. If
1696 config MODULE_SRCVERSION_ALL
1697 bool "Source checksum for all modules"
1699 Modules which contain a MODULE_VERSION get an extra "srcversion"
1700 field inserted into their modinfo section, which contains a
1701 sum of the source files which made it. This helps maintainers
1702 see exactly which source was used to build a module (since
1703 others sometimes change the module source without updating
1704 the version). With this option, such a "srcversion" field
1705 will be created for all modules. If unsure, say N.
1708 bool "Module signature verification"
1712 select ASYMMETRIC_KEY_TYPE
1713 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1714 select PUBLIC_KEY_ALGO_RSA
1717 select X509_CERTIFICATE_PARSER
1719 Check modules for valid signatures upon load: the signature
1720 is simply appended to the module. For more information see
1721 Documentation/module-signing.txt.
1723 !!!WARNING!!! If you enable this option, you MUST make sure that the
1724 module DOES NOT get stripped after being signed. This includes the
1725 debuginfo strip done by some packagers (such as rpmbuild) and
1726 inclusion into an initramfs that wants the module size reduced.
1728 config MODULE_SIG_FORCE
1729 bool "Require modules to be validly signed"
1730 depends on MODULE_SIG
1732 Reject unsigned modules or signed modules for which we don't have a
1733 key. Without this, such modules will simply taint the kernel.
1735 config MODULE_SIG_ALL
1736 bool "Automatically sign all modules"
1738 depends on MODULE_SIG
1740 Sign all modules during make modules_install. Without this option,
1741 modules must be signed manually, using the scripts/sign-file tool.
1743 comment "Do not forget to sign required modules with scripts/sign-file"
1744 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1747 prompt "Which hash algorithm should modules be signed with?"
1748 depends on MODULE_SIG
1750 This determines which sort of hashing algorithm will be used during
1751 signature generation. This algorithm _must_ be built into the kernel
1752 directly so that signature verification can take place. It is not
1753 possible to load a signed module containing the algorithm to check
1754 the signature on that module.
1756 config MODULE_SIG_SHA1
1757 bool "Sign modules with SHA-1"
1760 config MODULE_SIG_SHA224
1761 bool "Sign modules with SHA-224"
1762 select CRYPTO_SHA256
1764 config MODULE_SIG_SHA256
1765 bool "Sign modules with SHA-256"
1766 select CRYPTO_SHA256
1768 config MODULE_SIG_SHA384
1769 bool "Sign modules with SHA-384"
1770 select CRYPTO_SHA512
1772 config MODULE_SIG_SHA512
1773 bool "Sign modules with SHA-512"
1774 select CRYPTO_SHA512
1778 config MODULE_SIG_HASH
1780 depends on MODULE_SIG
1781 default "sha1" if MODULE_SIG_SHA1
1782 default "sha224" if MODULE_SIG_SHA224
1783 default "sha256" if MODULE_SIG_SHA256
1784 default "sha384" if MODULE_SIG_SHA384
1785 default "sha512" if MODULE_SIG_SHA512
1789 config INIT_ALL_POSSIBLE
1792 Back when each arch used to define their own cpu_online_mask and
1793 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1794 with all 1s, and others with all 0s. When they were centralised,
1795 it was better to provide this option than to break all the archs
1796 and have several arch maintainers pursuing me down dark alleys.
1801 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1803 Need stop_machine() primitive.
1805 source "block/Kconfig"
1807 config PREEMPT_NOTIFIERS
1814 # Can be selected by architectures with broken toolchains
1815 # that get confused by correct const<->read_only section
1817 config BROKEN_RODATA
1823 Build a simple ASN.1 grammar compiler that produces a bytecode output
1824 that can be interpreted by the ASN.1 stream decoder and used to
1825 inform it as to what tags are to be expected in a stream and what
1826 functions to call on what tags.
1828 source "kernel/Kconfig.locks"
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