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 string "Local version - append to kernel release"
59 Append an extra string to the end of your kernel version.
60 This will show up when you type uname, for example.
61 The string you set here will be appended after the contents of
62 any files with a filename matching localversion* in your
63 object and source tree, in that order. Your total string can
64 be a maximum of 64 characters.
66 config LOCALVERSION_AUTO
67 bool "Automatically append version information to the version string"
70 This will try to automatically determine if the current tree is a
71 release tree by looking for git tags that belong to the current
74 A string of the format -gxxxxxxxx will be added to the localversion
75 if a git-based tree is found. The string generated by this will be
76 appended after any matching localversion* files, and after the value
77 set in CONFIG_LOCALVERSION.
79 (The actual string used here is the first eight characters produced
80 by running the command:
82 $ git rev-parse --verify HEAD
84 which is done within the script "scripts/setlocalversion".)
86 config HAVE_KERNEL_GZIP
89 config HAVE_KERNEL_BZIP2
92 config HAVE_KERNEL_LZMA
98 config HAVE_KERNEL_LZO
102 prompt "Kernel compression mode"
104 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
106 The linux kernel is a kind of self-extracting executable.
107 Several compression algorithms are available, which differ
108 in efficiency, compression and decompression speed.
109 Compression speed is only relevant when building a kernel.
110 Decompression speed is relevant at each boot.
112 If you have any problems with bzip2 or lzma compressed
113 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
114 version of this functionality (bzip2 only), for 2.4, was
115 supplied by Christian Ludwig)
117 High compression options are mostly useful for users, who
118 are low on disk space (embedded systems), but for whom ram
121 If in doubt, select 'gzip'
125 depends on HAVE_KERNEL_GZIP
127 The old and tried gzip compression. It provides a good balance
128 between compression ratio and decompression speed.
132 depends on HAVE_KERNEL_BZIP2
134 Its compression ratio and speed is intermediate.
135 Decompression speed is slowest among the choices. The kernel
136 size is about 10% smaller with bzip2, in comparison to gzip.
137 Bzip2 uses a large amount of memory. For modern kernels you
138 will need at least 8MB RAM or more for booting.
142 depends on HAVE_KERNEL_LZMA
144 This compression algorithm's ratio is best. Decompression speed
145 is between gzip and bzip2. Compression is slowest.
146 The kernel size is about 33% smaller with LZMA in comparison to gzip.
150 depends on HAVE_KERNEL_XZ
152 XZ uses the LZMA2 algorithm and instruction set specific
153 BCJ filters which can improve compression ratio of executable
154 code. The size of the kernel is about 30% smaller with XZ in
155 comparison to gzip. On architectures for which there is a BCJ
156 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
157 will create a few percent smaller kernel than plain LZMA.
159 The speed is about the same as with LZMA: The decompression
160 speed of XZ is better than that of bzip2 but worse than gzip
161 and LZO. Compression is slow.
165 depends on HAVE_KERNEL_LZO
167 Its compression ratio is the poorest among the choices. The kernel
168 size is about 10% bigger than gzip; however its speed
169 (both compression and decompression) is the fastest.
173 config DEFAULT_HOSTNAME
174 string "Default hostname"
177 This option determines the default system hostname before userspace
178 calls sethostname(2). The kernel traditionally uses "(none)" here,
179 but you may wish to use a different default here to make a minimal
180 system more usable with less configuration.
183 bool "Support for paging of anonymous memory (swap)"
184 depends on MMU && BLOCK
187 This option allows you to choose whether you want to have support
188 for so called swap devices or swap files in your kernel that are
189 used to provide more virtual memory than the actual RAM present
190 in your computer. If unsure say Y.
195 Inter Process Communication is a suite of library functions and
196 system calls which let processes (running programs) synchronize and
197 exchange information. It is generally considered to be a good thing,
198 and some programs won't run unless you say Y here. In particular, if
199 you want to run the DOS emulator dosemu under Linux (read the
200 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
201 you'll need to say Y here.
203 You can find documentation about IPC with "info ipc" and also in
204 section 6.4 of the Linux Programmer's Guide, available from
205 <http://www.tldp.org/guides.html>.
207 config SYSVIPC_SYSCTL
214 bool "POSIX Message Queues"
217 POSIX variant of message queues is a part of IPC. In POSIX message
218 queues every message has a priority which decides about succession
219 of receiving it by a process. If you want to compile and run
220 programs written e.g. for Solaris with use of its POSIX message
221 queues (functions mq_*) say Y here.
223 POSIX message queues are visible as a filesystem called 'mqueue'
224 and can be mounted somewhere if you want to do filesystem
225 operations on message queues.
229 config POSIX_MQUEUE_SYSCTL
231 depends on POSIX_MQUEUE
236 bool "open by fhandle syscalls"
239 If you say Y here, a user level program will be able to map
240 file names to handle and then later use the handle for
241 different file system operations. This is useful in implementing
242 userspace file servers, which now track files using handles instead
243 of names. The handle would remain the same even if file names
244 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
248 bool "Auditing support"
251 Enable auditing infrastructure that can be used with another
252 kernel subsystem, such as SELinux (which requires this for
253 logging of avc messages output). Does not do system-call
254 auditing without CONFIG_AUDITSYSCALL.
257 bool "Enable system-call auditing support"
258 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
259 default y if SECURITY_SELINUX
261 Enable low-overhead system-call auditing infrastructure that
262 can be used independently or with another kernel subsystem,
267 depends on AUDITSYSCALL
272 depends on AUDITSYSCALL
275 config AUDIT_LOGINUID_IMMUTABLE
276 bool "Make audit loginuid immutable"
279 The config option toggles if a task setting its loginuid requires
280 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
281 but should instead only allow setting its loginuid if it was never
282 previously set. On systems which use systemd or a similar central
283 process to restart login services this should be set to true. On older
284 systems in which an admin would typically have to directly stop and
285 start processes this should be set to false. Setting this to true allows
286 one to drop potentially dangerous capabilites from the login tasks,
287 but may not be backwards compatible with older init systems.
289 source "kernel/irq/Kconfig"
290 source "kernel/time/Kconfig"
292 menu "CPU/Task time and stats accounting"
294 config VIRT_CPU_ACCOUNTING
298 prompt "Cputime accounting"
299 default TICK_CPU_ACCOUNTING if !PPC64
300 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
302 # Kind of a stub config for the pure tick based cputime accounting
303 config TICK_CPU_ACCOUNTING
304 bool "Simple tick based cputime accounting"
305 depends on !S390 && !NO_HZ_FULL
307 This is the basic tick based cputime accounting that maintains
308 statistics about user, system and idle time spent on per jiffies
313 config VIRT_CPU_ACCOUNTING_NATIVE
314 bool "Deterministic task and CPU time accounting"
315 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
316 select VIRT_CPU_ACCOUNTING
318 Select this option to enable more accurate task and CPU time
319 accounting. This is done by reading a CPU counter on each
320 kernel entry and exit and on transitions within the kernel
321 between system, softirq and hardirq state, so there is a
322 small performance impact. In the case of s390 or IBM POWER > 5,
323 this also enables accounting of stolen time on logically-partitioned
326 config VIRT_CPU_ACCOUNTING_GEN
327 bool "Full dynticks CPU time accounting"
328 depends on HAVE_CONTEXT_TRACKING && 64BIT
329 select VIRT_CPU_ACCOUNTING
330 select CONTEXT_TRACKING
332 Select this option to enable task and CPU time accounting on full
333 dynticks systems. This accounting is implemented by watching every
334 kernel-user boundaries using the context tracking subsystem.
335 The accounting is thus performed at the expense of some significant
338 For now this is only useful if you are working on the full
339 dynticks subsystem development.
343 config IRQ_TIME_ACCOUNTING
344 bool "Fine granularity task level IRQ time accounting"
345 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
347 Select this option to enable fine granularity task irq time
348 accounting. This is done by reading a timestamp on each
349 transitions between softirq and hardirq state, so there can be a
350 small performance impact.
352 If in doubt, say N here.
356 config BSD_PROCESS_ACCT
357 bool "BSD Process Accounting"
359 If you say Y here, a user level program will be able to instruct the
360 kernel (via a special system call) to write process accounting
361 information to a file: whenever a process exits, information about
362 that process will be appended to the file by the kernel. The
363 information includes things such as creation time, owning user,
364 command name, memory usage, controlling terminal etc. (the complete
365 list is in the struct acct in <file:include/linux/acct.h>). It is
366 up to the user level program to do useful things with this
367 information. This is generally a good idea, so say Y.
369 config BSD_PROCESS_ACCT_V3
370 bool "BSD Process Accounting version 3 file format"
371 depends on BSD_PROCESS_ACCT
374 If you say Y here, the process accounting information is written
375 in a new file format that also logs the process IDs of each
376 process and it's parent. Note that this file format is incompatible
377 with previous v0/v1/v2 file formats, so you will need updated tools
378 for processing it. A preliminary version of these tools is available
379 at <http://www.gnu.org/software/acct/>.
382 bool "Export task/process statistics through netlink"
386 Export selected statistics for tasks/processes through the
387 generic netlink interface. Unlike BSD process accounting, the
388 statistics are available during the lifetime of tasks/processes as
389 responses to commands. Like BSD accounting, they are sent to user
394 config TASK_DELAY_ACCT
395 bool "Enable per-task delay accounting"
398 Collect information on time spent by a task waiting for system
399 resources like cpu, synchronous block I/O completion and swapping
400 in pages. Such statistics can help in setting a task's priorities
401 relative to other tasks for cpu, io, rss limits etc.
406 bool "Enable extended accounting over taskstats"
409 Collect extended task accounting data and send the data
410 to userland for processing over the taskstats interface.
414 config TASK_IO_ACCOUNTING
415 bool "Enable per-task storage I/O accounting"
416 depends on TASK_XACCT
418 Collect information on the number of bytes of storage I/O which this
423 endmenu # "CPU/Task time and stats accounting"
428 prompt "RCU Implementation"
432 bool "Tree-based hierarchical RCU"
433 depends on !PREEMPT && SMP
436 This option selects the RCU implementation that is
437 designed for very large SMP system with hundreds or
438 thousands of CPUs. It also scales down nicely to
441 config TREE_PREEMPT_RCU
442 bool "Preemptible tree-based hierarchical RCU"
445 This option selects the RCU implementation that is
446 designed for very large SMP systems with hundreds or
447 thousands of CPUs, but for which real-time response
448 is also required. It also scales down nicely to
451 Select this option if you are unsure.
454 bool "UP-only small-memory-footprint RCU"
455 depends on !PREEMPT && !SMP
457 This option selects the RCU implementation that is
458 designed for UP systems from which real-time response
459 is not required. This option greatly reduces the
460 memory footprint of RCU.
462 config TINY_PREEMPT_RCU
463 bool "Preemptible UP-only small-memory-footprint RCU"
464 depends on PREEMPT && !SMP
466 This option selects the RCU implementation that is designed
467 for real-time UP systems. This option greatly reduces the
468 memory footprint of RCU.
473 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
475 This option enables preemptible-RCU code that is common between
476 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
478 config RCU_STALL_COMMON
479 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
481 This option enables RCU CPU stall code that is common between
482 the TINY and TREE variants of RCU. The purpose is to allow
483 the tiny variants to disable RCU CPU stall warnings, while
484 making these warnings mandatory for the tree variants.
486 config CONTEXT_TRACKING
490 bool "Consider userspace as in RCU extended quiescent state"
491 depends on HAVE_CONTEXT_TRACKING && SMP
492 select CONTEXT_TRACKING
494 This option sets hooks on kernel / userspace boundaries and
495 puts RCU in extended quiescent state when the CPU runs in
496 userspace. It means that when a CPU runs in userspace, it is
497 excluded from the global RCU state machine and thus doesn't
498 try to keep the timer tick on for RCU.
500 Unless you want to hack and help the development of the full
501 dynticks mode, you shouldn't enable this option. It also
502 adds unnecessary overhead.
506 config CONTEXT_TRACKING_FORCE
507 bool "Force context tracking"
508 depends on CONTEXT_TRACKING
509 default CONTEXT_TRACKING
511 Probe on user/kernel boundaries by default in order to
512 test the features that rely on it such as userspace RCU extended
514 This test is there for debugging until we have a real user like the
518 int "Tree-based hierarchical RCU fanout value"
521 depends on TREE_RCU || TREE_PREEMPT_RCU
525 This option controls the fanout of hierarchical implementations
526 of RCU, allowing RCU to work efficiently on machines with
527 large numbers of CPUs. This value must be at least the fourth
528 root of NR_CPUS, which allows NR_CPUS to be insanely large.
529 The default value of RCU_FANOUT should be used for production
530 systems, but if you are stress-testing the RCU implementation
531 itself, small RCU_FANOUT values allow you to test large-system
532 code paths on small(er) systems.
534 Select a specific number if testing RCU itself.
535 Take the default if unsure.
537 config RCU_FANOUT_LEAF
538 int "Tree-based hierarchical RCU leaf-level fanout value"
539 range 2 RCU_FANOUT if 64BIT
540 range 2 RCU_FANOUT if !64BIT
541 depends on TREE_RCU || TREE_PREEMPT_RCU
544 This option controls the leaf-level fanout of hierarchical
545 implementations of RCU, and allows trading off cache misses
546 against lock contention. Systems that synchronize their
547 scheduling-clock interrupts for energy-efficiency reasons will
548 want the default because the smaller leaf-level fanout keeps
549 lock contention levels acceptably low. Very large systems
550 (hundreds or thousands of CPUs) will instead want to set this
551 value to the maximum value possible in order to reduce the
552 number of cache misses incurred during RCU's grace-period
553 initialization. These systems tend to run CPU-bound, and thus
554 are not helped by synchronized interrupts, and thus tend to
555 skew them, which reduces lock contention enough that large
556 leaf-level fanouts work well.
558 Select a specific number if testing RCU itself.
560 Select the maximum permissible value for large systems.
562 Take the default if unsure.
564 config RCU_FANOUT_EXACT
565 bool "Disable tree-based hierarchical RCU auto-balancing"
566 depends on TREE_RCU || TREE_PREEMPT_RCU
569 This option forces use of the exact RCU_FANOUT value specified,
570 regardless of imbalances in the hierarchy. This is useful for
571 testing RCU itself, and might one day be useful on systems with
572 strong NUMA behavior.
574 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
578 config RCU_FAST_NO_HZ
579 bool "Accelerate last non-dyntick-idle CPU's grace periods"
580 depends on NO_HZ_COMMON && SMP
583 This option permits CPUs to enter dynticks-idle state even if
584 they have RCU callbacks queued, and prevents RCU from waking
585 these CPUs up more than roughly once every four jiffies (by
586 default, you can adjust this using the rcutree.rcu_idle_gp_delay
587 parameter), thus improving energy efficiency. On the other
588 hand, this option increases the duration of RCU grace periods,
589 for example, slowing down synchronize_rcu().
591 Say Y if energy efficiency is critically important, and you
592 don't care about increased grace-period durations.
594 Say N if you are unsure.
596 config TREE_RCU_TRACE
597 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
600 This option provides tracing for the TREE_RCU and
601 TREE_PREEMPT_RCU implementations, permitting Makefile to
602 trivially select kernel/rcutree_trace.c.
605 bool "Enable RCU priority boosting"
606 depends on RT_MUTEXES && PREEMPT_RCU
609 This option boosts the priority of preempted RCU readers that
610 block the current preemptible RCU grace period for too long.
611 This option also prevents heavy loads from blocking RCU
612 callback invocation for all flavors of RCU.
614 Say Y here if you are working with real-time apps or heavy loads
615 Say N here if you are unsure.
617 config RCU_BOOST_PRIO
618 int "Real-time priority to boost RCU readers to"
623 This option specifies the real-time priority to which long-term
624 preempted RCU readers are to be boosted. If you are working
625 with a real-time application that has one or more CPU-bound
626 threads running at a real-time priority level, you should set
627 RCU_BOOST_PRIO to a priority higher then the highest-priority
628 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
629 of 1 is appropriate in the common case, which is real-time
630 applications that do not have any CPU-bound threads.
632 Some real-time applications might not have a single real-time
633 thread that saturates a given CPU, but instead might have
634 multiple real-time threads that, taken together, fully utilize
635 that CPU. In this case, you should set RCU_BOOST_PRIO to
636 a priority higher than the lowest-priority thread that is
637 conspiring to prevent the CPU from running any non-real-time
638 tasks. For example, if one thread at priority 10 and another
639 thread at priority 5 are between themselves fully consuming
640 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
641 set to priority 6 or higher.
643 Specify the real-time priority, or take the default if unsure.
645 config RCU_BOOST_DELAY
646 int "Milliseconds to delay boosting after RCU grace-period start"
651 This option specifies the time to wait after the beginning of
652 a given grace period before priority-boosting preempted RCU
653 readers blocking that grace period. Note that any RCU reader
654 blocking an expedited RCU grace period is boosted immediately.
656 Accept the default if unsure.
659 bool "Offload RCU callback processing from boot-selected CPUs (EXPERIMENTAL"
660 depends on TREE_RCU || TREE_PREEMPT_RCU
663 Use this option to reduce OS jitter for aggressive HPC or
664 real-time workloads. It can also be used to offload RCU
665 callback invocation to energy-efficient CPUs in battery-powered
666 asymmetric multiprocessors.
668 This option offloads callback invocation from the set of
669 CPUs specified at boot time by the rcu_nocbs parameter.
670 For each such CPU, a kthread ("rcuox/N") will be created to
671 invoke callbacks, where the "N" is the CPU being offloaded,
672 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
673 "s" for RCU-sched. Nothing prevents this kthread from running
674 on the specified CPUs, but (1) the kthreads may be preempted
675 between each callback, and (2) affinity or cgroups can be used
676 to force the kthreads to run on whatever set of CPUs is desired.
678 Say Y here if you want to help to debug reduced OS jitter.
679 Say N here if you are unsure.
682 prompt "Build-forced no-CBs CPUs"
683 default RCU_NOCB_CPU_NONE
685 This option allows no-CBs CPUs to be specified at build time.
686 Additional no-CBs CPUs may be specified by the rcu_nocbs=
689 config RCU_NOCB_CPU_NONE
690 bool "No build_forced no-CBs CPUs"
691 depends on RCU_NOCB_CPU && !NO_HZ_FULL
693 This option does not force any of the CPUs to be no-CBs CPUs.
694 Only CPUs designated by the rcu_nocbs= boot parameter will be
697 config RCU_NOCB_CPU_ZERO
698 bool "CPU 0 is a build_forced no-CBs CPU"
699 depends on RCU_NOCB_CPU && !NO_HZ_FULL
701 This option forces CPU 0 to be a no-CBs CPU. Additional CPUs
702 may be designated as no-CBs CPUs using the rcu_nocbs= boot
703 parameter will be no-CBs CPUs.
705 Select this if CPU 0 needs to be a no-CBs CPU for real-time
706 or energy-efficiency reasons.
708 config RCU_NOCB_CPU_ALL
709 bool "All CPUs are build_forced no-CBs CPUs"
710 depends on RCU_NOCB_CPU
712 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
713 boot parameter will be ignored.
715 Select this if all CPUs need to be no-CBs CPUs for real-time
716 or energy-efficiency reasons.
720 endmenu # "RCU Subsystem"
723 tristate "Kernel .config support"
725 This option enables the complete Linux kernel ".config" file
726 contents to be saved in the kernel. It provides documentation
727 of which kernel options are used in a running kernel or in an
728 on-disk kernel. This information can be extracted from the kernel
729 image file with the script scripts/extract-ikconfig and used as
730 input to rebuild the current kernel or to build another kernel.
731 It can also be extracted from a running kernel by reading
732 /proc/config.gz if enabled (below).
735 bool "Enable access to .config through /proc/config.gz"
736 depends on IKCONFIG && PROC_FS
738 This option enables access to the kernel configuration file
739 through /proc/config.gz.
742 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
746 Select kernel log buffer size as a power of 2.
756 # Architectures with an unreliable sched_clock() should select this:
758 config HAVE_UNSTABLE_SCHED_CLOCK
761 config GENERIC_SCHED_CLOCK
765 # For architectures that want to enable the support for NUMA-affine scheduler
768 config ARCH_SUPPORTS_NUMA_BALANCING
771 # For architectures that (ab)use NUMA to represent different memory regions
772 # all cpu-local but of different latencies, such as SuperH.
774 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
778 # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
779 config ARCH_WANTS_PROT_NUMA_PROT_NONE
782 config ARCH_USES_NUMA_PROT_NONE
785 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
786 depends on NUMA_BALANCING
788 config NUMA_BALANCING_DEFAULT_ENABLED
789 bool "Automatically enable NUMA aware memory/task placement"
791 depends on NUMA_BALANCING
793 If set, autonumic NUMA balancing will be enabled if running on a NUMA
796 config NUMA_BALANCING
797 bool "Memory placement aware NUMA scheduler"
798 depends on ARCH_SUPPORTS_NUMA_BALANCING
799 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
800 depends on SMP && NUMA && MIGRATION
802 This option adds support for automatic NUMA aware memory/task placement.
803 The mechanism is quite primitive and is based on migrating memory when
804 it is references to the node the task is running on.
806 This system will be inactive on UMA systems.
809 boolean "Control Group support"
812 This option adds support for grouping sets of processes together, for
813 use with process control subsystems such as Cpusets, CFS, memory
814 controls or device isolation.
816 - Documentation/scheduler/sched-design-CFS.txt (CFS)
817 - Documentation/cgroups/ (features for grouping, isolation
818 and resource control)
825 bool "Example debug cgroup subsystem"
828 This option enables a simple cgroup subsystem that
829 exports useful debugging information about the cgroups
834 config CGROUP_FREEZER
835 bool "Freezer cgroup subsystem"
837 Provides a way to freeze and unfreeze all tasks in a
841 bool "Device controller for cgroups"
843 Provides a cgroup implementing whitelists for devices which
844 a process in the cgroup can mknod or open.
847 bool "Cpuset support"
849 This option will let you create and manage CPUSETs which
850 allow dynamically partitioning a system into sets of CPUs and
851 Memory Nodes and assigning tasks to run only within those sets.
852 This is primarily useful on large SMP or NUMA systems.
856 config PROC_PID_CPUSET
857 bool "Include legacy /proc/<pid>/cpuset file"
861 config CGROUP_CPUACCT
862 bool "Simple CPU accounting cgroup subsystem"
864 Provides a simple Resource Controller for monitoring the
865 total CPU consumed by the tasks in a cgroup.
867 config RESOURCE_COUNTERS
868 bool "Resource counters"
870 This option enables controller independent resource accounting
871 infrastructure that works with cgroups.
874 bool "Memory Resource Controller for Control Groups"
875 depends on RESOURCE_COUNTERS
878 Provides a memory resource controller that manages both anonymous
879 memory and page cache. (See Documentation/cgroups/memory.txt)
881 Note that setting this option increases fixed memory overhead
882 associated with each page of memory in the system. By this,
883 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
884 usage tracking struct at boot. Total amount of this is printed out
887 Only enable when you're ok with these trade offs and really
888 sure you need the memory resource controller. Even when you enable
889 this, you can set "cgroup_disable=memory" at your boot option to
890 disable memory resource controller and you can avoid overheads.
891 (and lose benefits of memory resource controller)
893 This config option also selects MM_OWNER config option, which
894 could in turn add some fork/exit overhead.
897 bool "Memory Resource Controller Swap Extension"
898 depends on MEMCG && SWAP
900 Add swap management feature to memory resource controller. When you
901 enable this, you can limit mem+swap usage per cgroup. In other words,
902 when you disable this, memory resource controller has no cares to
903 usage of swap...a process can exhaust all of the swap. This extension
904 is useful when you want to avoid exhaustion swap but this itself
905 adds more overheads and consumes memory for remembering information.
906 Especially if you use 32bit system or small memory system, please
907 be careful about enabling this. When memory resource controller
908 is disabled by boot option, this will be automatically disabled and
909 there will be no overhead from this. Even when you set this config=y,
910 if boot option "swapaccount=0" is set, swap will not be accounted.
911 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
912 size is 4096bytes, 512k per 1Gbytes of swap.
913 config MEMCG_SWAP_ENABLED
914 bool "Memory Resource Controller Swap Extension enabled by default"
915 depends on MEMCG_SWAP
918 Memory Resource Controller Swap Extension comes with its price in
919 a bigger memory consumption. General purpose distribution kernels
920 which want to enable the feature but keep it disabled by default
921 and let the user enable it by swapaccount boot command line
922 parameter should have this option unselected.
923 For those who want to have the feature enabled by default should
924 select this option (if, for some reason, they need to disable it
925 then swapaccount=0 does the trick).
927 bool "Memory Resource Controller Kernel Memory accounting"
929 depends on SLUB || SLAB
931 The Kernel Memory extension for Memory Resource Controller can limit
932 the amount of memory used by kernel objects in the system. Those are
933 fundamentally different from the entities handled by the standard
934 Memory Controller, which are page-based, and can be swapped. Users of
935 the kmem extension can use it to guarantee that no group of processes
936 will ever exhaust kernel resources alone.
938 config CGROUP_HUGETLB
939 bool "HugeTLB Resource Controller for Control Groups"
940 depends on RESOURCE_COUNTERS && HUGETLB_PAGE
943 Provides a cgroup Resource Controller for HugeTLB pages.
944 When you enable this, you can put a per cgroup limit on HugeTLB usage.
945 The limit is enforced during page fault. Since HugeTLB doesn't
946 support page reclaim, enforcing the limit at page fault time implies
947 that, the application will get SIGBUS signal if it tries to access
948 HugeTLB pages beyond its limit. This requires the application to know
949 beforehand how much HugeTLB pages it would require for its use. The
950 control group is tracked in the third page lru pointer. This means
951 that we cannot use the controller with huge page less than 3 pages.
954 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
955 depends on PERF_EVENTS && CGROUPS
957 This option extends the per-cpu mode to restrict monitoring to
958 threads which belong to the cgroup specified and run on the
963 menuconfig CGROUP_SCHED
964 bool "Group CPU scheduler"
967 This feature lets CPU scheduler recognize task groups and control CPU
968 bandwidth allocation to such task groups. It uses cgroups to group
972 config FAIR_GROUP_SCHED
973 bool "Group scheduling for SCHED_OTHER"
974 depends on CGROUP_SCHED
978 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
979 depends on FAIR_GROUP_SCHED
982 This option allows users to define CPU bandwidth rates (limits) for
983 tasks running within the fair group scheduler. Groups with no limit
984 set are considered to be unconstrained and will run with no
986 See tip/Documentation/scheduler/sched-bwc.txt for more information.
988 config RT_GROUP_SCHED
989 bool "Group scheduling for SCHED_RR/FIFO"
990 depends on CGROUP_SCHED
993 This feature lets you explicitly allocate real CPU bandwidth
994 to task groups. If enabled, it will also make it impossible to
995 schedule realtime tasks for non-root users until you allocate
996 realtime bandwidth for them.
997 See Documentation/scheduler/sched-rt-group.txt for more information.
1002 bool "Block IO controller"
1006 Generic block IO controller cgroup interface. This is the common
1007 cgroup interface which should be used by various IO controlling
1010 Currently, CFQ IO scheduler uses it to recognize task groups and
1011 control disk bandwidth allocation (proportional time slice allocation)
1012 to such task groups. It is also used by bio throttling logic in
1013 block layer to implement upper limit in IO rates on a device.
1015 This option only enables generic Block IO controller infrastructure.
1016 One needs to also enable actual IO controlling logic/policy. For
1017 enabling proportional weight division of disk bandwidth in CFQ, set
1018 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1019 CONFIG_BLK_DEV_THROTTLING=y.
1021 See Documentation/cgroups/blkio-controller.txt for more information.
1023 config DEBUG_BLK_CGROUP
1024 bool "Enable Block IO controller debugging"
1025 depends on BLK_CGROUP
1028 Enable some debugging help. Currently it exports additional stat
1029 files in a cgroup which can be useful for debugging.
1033 config CHECKPOINT_RESTORE
1034 bool "Checkpoint/restore support" if EXPERT
1037 Enables additional kernel features in a sake of checkpoint/restore.
1038 In particular it adds auxiliary prctl codes to setup process text,
1039 data and heap segment sizes, and a few additional /proc filesystem
1042 If unsure, say N here.
1044 menuconfig NAMESPACES
1045 bool "Namespaces support" if EXPERT
1048 Provides the way to make tasks work with different objects using
1049 the same id. For example same IPC id may refer to different objects
1050 or same user id or pid may refer to different tasks when used in
1051 different namespaces.
1056 bool "UTS namespace"
1059 In this namespace tasks see different info provided with the
1063 bool "IPC namespace"
1064 depends on (SYSVIPC || POSIX_MQUEUE)
1067 In this namespace tasks work with IPC ids which correspond to
1068 different IPC objects in different namespaces.
1071 bool "User namespace"
1072 depends on UIDGID_CONVERTED
1073 select UIDGID_STRICT_TYPE_CHECKS
1077 This allows containers, i.e. vservers, to use user namespaces
1078 to provide different user info for different servers.
1080 When user namespaces are enabled in the kernel it is
1081 recommended that the MEMCG and MEMCG_KMEM options also be
1082 enabled and that user-space use the memory control groups to
1083 limit the amount of memory a memory unprivileged users can
1089 bool "PID Namespaces"
1092 Support process id namespaces. This allows having multiple
1093 processes with the same pid as long as they are in different
1094 pid namespaces. This is a building block of containers.
1097 bool "Network namespace"
1101 Allow user space to create what appear to be multiple instances
1102 of the network stack.
1106 config UIDGID_CONVERTED
1107 # True if all of the selected software conmponents are known
1108 # to have uid_t and gid_t converted to kuid_t and kgid_t
1109 # where appropriate and are otherwise safe to use with
1110 # the user namespace.
1115 depends on XFS_FS = n
1117 config UIDGID_STRICT_TYPE_CHECKS
1118 bool "Require conversions between uid/gids and their internal representation"
1119 depends on UIDGID_CONVERTED
1122 While the nececessary conversions are being added to all subsystems this option allows
1123 the code to continue to build for unconverted subsystems.
1125 Say Y here if you want the strict type checking enabled
1127 config SCHED_AUTOGROUP
1128 bool "Automatic process group scheduling"
1132 select FAIR_GROUP_SCHED
1134 This option optimizes the scheduler for common desktop workloads by
1135 automatically creating and populating task groups. This separation
1136 of workloads isolates aggressive CPU burners (like build jobs) from
1137 desktop applications. Task group autogeneration is currently based
1143 config SYSFS_DEPRECATED
1144 bool "Enable deprecated sysfs features to support old userspace tools"
1148 This option adds code that switches the layout of the "block" class
1149 devices, to not show up in /sys/class/block/, but only in
1152 This switch is only active when the sysfs.deprecated=1 boot option is
1153 passed or the SYSFS_DEPRECATED_V2 option is set.
1155 This option allows new kernels to run on old distributions and tools,
1156 which might get confused by /sys/class/block/. Since 2007/2008 all
1157 major distributions and tools handle this just fine.
1159 Recent distributions and userspace tools after 2009/2010 depend on
1160 the existence of /sys/class/block/, and will not work with this
1163 Only if you are using a new kernel on an old distribution, you might
1166 config SYSFS_DEPRECATED_V2
1167 bool "Enable deprecated sysfs features by default"
1170 depends on SYSFS_DEPRECATED
1172 Enable deprecated sysfs by default.
1174 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1177 Only if you are using a new kernel on an old distribution, you might
1178 need to say Y here. Even then, odds are you would not need it
1179 enabled, you can always pass the boot option if absolutely necessary.
1182 bool "Kernel->user space relay support (formerly relayfs)"
1184 This option enables support for relay interface support in
1185 certain file systems (such as debugfs).
1186 It is designed to provide an efficient mechanism for tools and
1187 facilities to relay large amounts of data from kernel space to
1192 config BLK_DEV_INITRD
1193 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1194 depends on BROKEN || !FRV
1196 The initial RAM filesystem is a ramfs which is loaded by the
1197 boot loader (loadlin or lilo) and that is mounted as root
1198 before the normal boot procedure. It is typically used to
1199 load modules needed to mount the "real" root file system,
1200 etc. See <file:Documentation/initrd.txt> for details.
1202 If RAM disk support (BLK_DEV_RAM) is also included, this
1203 also enables initial RAM disk (initrd) support and adds
1204 15 Kbytes (more on some other architectures) to the kernel size.
1210 source "usr/Kconfig"
1214 config CC_OPTIMIZE_FOR_SIZE
1215 bool "Optimize for size"
1217 Enabling this option will pass "-Os" instead of "-O2" to gcc
1218 resulting in a smaller kernel.
1231 config SYSCTL_EXCEPTION_TRACE
1234 Enable support for /proc/sys/debug/exception-trace.
1236 config SYSCTL_ARCH_UNALIGN_NO_WARN
1239 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1240 Allows arch to define/use @no_unaligned_warning to possibly warn
1241 about unaligned access emulation going on under the hood.
1243 config SYSCTL_ARCH_UNALIGN_ALLOW
1246 Enable support for /proc/sys/kernel/unaligned-trap
1247 Allows arches to define/use @unaligned_enabled to runtime toggle
1248 the unaligned access emulation.
1249 see arch/parisc/kernel/unaligned.c for reference
1254 config HAVE_PCSPKR_PLATFORM
1257 config PANIC_TIMEOUT
1258 int "Default panic timeout"
1261 Set default panic timeout.
1264 bool "Configure standard kernel features (expert users)"
1265 # Unhide debug options, to make the on-by-default options visible
1268 This option allows certain base kernel options and settings
1269 to be disabled or tweaked. This is for specialized
1270 environments which can tolerate a "non-standard" kernel.
1271 Only use this if you really know what you are doing.
1274 bool "Enable 16-bit UID system calls" if EXPERT
1275 depends on HAVE_UID16
1278 This enables the legacy 16-bit UID syscall wrappers.
1280 config SYSCTL_SYSCALL
1281 bool "Sysctl syscall support" if EXPERT
1282 depends on PROC_SYSCTL
1286 sys_sysctl uses binary paths that have been found challenging
1287 to properly maintain and use. The interface in /proc/sys
1288 using paths with ascii names is now the primary path to this
1291 Almost nothing using the binary sysctl interface so if you are
1292 trying to save some space it is probably safe to disable this,
1293 making your kernel marginally smaller.
1295 If unsure say N here.
1298 bool "Load all symbols for debugging/ksymoops" if EXPERT
1301 Say Y here to let the kernel print out symbolic crash information and
1302 symbolic stack backtraces. This increases the size of the kernel
1303 somewhat, as all symbols have to be loaded into the kernel image.
1306 bool "Include all symbols in kallsyms"
1307 depends on DEBUG_KERNEL && KALLSYMS
1309 Normally kallsyms only contains the symbols of functions for nicer
1310 OOPS messages and backtraces (i.e., symbols from the text and inittext
1311 sections). This is sufficient for most cases. And only in very rare
1312 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1313 names of variables from the data sections, etc).
1315 This option makes sure that all symbols are loaded into the kernel
1316 image (i.e., symbols from all sections) in cost of increased kernel
1317 size (depending on the kernel configuration, it may be 300KiB or
1318 something like this).
1320 Say N unless you really need all symbols.
1324 bool "Enable support for printk" if EXPERT
1327 This option enables normal printk support. Removing it
1328 eliminates most of the message strings from the kernel image
1329 and makes the kernel more or less silent. As this makes it
1330 very difficult to diagnose system problems, saying N here is
1331 strongly discouraged.
1334 bool "BUG() support" if EXPERT
1337 Disabling this option eliminates support for BUG and WARN, reducing
1338 the size of your kernel image and potentially quietly ignoring
1339 numerous fatal conditions. You should only consider disabling this
1340 option for embedded systems with no facilities for reporting errors.
1346 bool "Enable ELF core dumps" if EXPERT
1348 Enable support for generating core dumps. Disabling saves about 4k.
1351 config PCSPKR_PLATFORM
1352 bool "Enable PC-Speaker support" if EXPERT
1353 depends on HAVE_PCSPKR_PLATFORM
1357 This option allows to disable the internal PC-Speaker
1358 support, saving some memory.
1362 bool "Enable full-sized data structures for core" if EXPERT
1364 Disabling this option reduces the size of miscellaneous core
1365 kernel data structures. This saves memory on small machines,
1366 but may reduce performance.
1369 bool "Enable futex support" if EXPERT
1373 Disabling this option will cause the kernel to be built without
1374 support for "fast userspace mutexes". The resulting kernel may not
1375 run glibc-based applications correctly.
1377 config HAVE_FUTEX_CMPXCHG
1381 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1382 is implemented and always working. This removes a couple of runtime
1386 bool "Enable eventpoll support" if EXPERT
1390 Disabling this option will cause the kernel to be built without
1391 support for epoll family of system calls.
1394 bool "Enable signalfd() system call" if EXPERT
1398 Enable the signalfd() system call that allows to receive signals
1399 on a file descriptor.
1404 bool "Enable timerfd() system call" if EXPERT
1408 Enable the timerfd() system call that allows to receive timer
1409 events on a file descriptor.
1414 bool "Enable eventfd() system call" if EXPERT
1418 Enable the eventfd() system call that allows to receive both
1419 kernel notification (ie. KAIO) or userspace notifications.
1424 bool "Use full shmem filesystem" if EXPERT
1428 The shmem is an internal filesystem used to manage shared memory.
1429 It is backed by swap and manages resource limits. It is also exported
1430 to userspace as tmpfs if TMPFS is enabled. Disabling this
1431 option replaces shmem and tmpfs with the much simpler ramfs code,
1432 which may be appropriate on small systems without swap.
1435 bool "Enable AIO support" if EXPERT
1438 This option enables POSIX asynchronous I/O which may by used
1439 by some high performance threaded applications. Disabling
1440 this option saves about 7k.
1444 bool "Enable PCI quirk workarounds" if EXPERT
1447 This enables workarounds for various PCI chipset
1448 bugs/quirks. Disable this only if your target machine is
1449 unaffected by PCI quirks.
1452 bool "Embedded system"
1455 This option should be enabled if compiling the kernel for
1456 an embedded system so certain expert options are available
1459 config HAVE_PERF_EVENTS
1462 See tools/perf/design.txt for details.
1464 config PERF_USE_VMALLOC
1467 See tools/perf/design.txt for details
1469 menu "Kernel Performance Events And Counters"
1472 bool "Kernel performance events and counters"
1473 default y if PROFILING
1474 depends on HAVE_PERF_EVENTS
1478 Enable kernel support for various performance events provided
1479 by software and hardware.
1481 Software events are supported either built-in or via the
1482 use of generic tracepoints.
1484 Most modern CPUs support performance events via performance
1485 counter registers. These registers count the number of certain
1486 types of hw events: such as instructions executed, cachemisses
1487 suffered, or branches mis-predicted - without slowing down the
1488 kernel or applications. These registers can also trigger interrupts
1489 when a threshold number of events have passed - and can thus be
1490 used to profile the code that runs on that CPU.
1492 The Linux Performance Event subsystem provides an abstraction of
1493 these software and hardware event capabilities, available via a
1494 system call and used by the "perf" utility in tools/perf/. It
1495 provides per task and per CPU counters, and it provides event
1496 capabilities on top of those.
1500 config DEBUG_PERF_USE_VMALLOC
1502 bool "Debug: use vmalloc to back perf mmap() buffers"
1503 depends on PERF_EVENTS && DEBUG_KERNEL
1504 select PERF_USE_VMALLOC
1506 Use vmalloc memory to back perf mmap() buffers.
1508 Mostly useful for debugging the vmalloc code on platforms
1509 that don't require it.
1515 config VM_EVENT_COUNTERS
1517 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1519 VM event counters are needed for event counts to be shown.
1520 This option allows the disabling of the VM event counters
1521 on EXPERT systems. /proc/vmstat will only show page counts
1522 if VM event counters are disabled.
1526 bool "Enable SLUB debugging support" if EXPERT
1527 depends on SLUB && SYSFS
1529 SLUB has extensive debug support features. Disabling these can
1530 result in significant savings in code size. This also disables
1531 SLUB sysfs support. /sys/slab will not exist and there will be
1532 no support for cache validation etc.
1535 bool "Disable heap randomization"
1538 Randomizing heap placement makes heap exploits harder, but it
1539 also breaks ancient binaries (including anything libc5 based).
1540 This option changes the bootup default to heap randomization
1541 disabled, and can be overridden at runtime by setting
1542 /proc/sys/kernel/randomize_va_space to 2.
1544 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1547 prompt "Choose SLAB allocator"
1550 This option allows to select a slab allocator.
1555 The regular slab allocator that is established and known to work
1556 well in all environments. It organizes cache hot objects in
1557 per cpu and per node queues.
1560 bool "SLUB (Unqueued Allocator)"
1562 SLUB is a slab allocator that minimizes cache line usage
1563 instead of managing queues of cached objects (SLAB approach).
1564 Per cpu caching is realized using slabs of objects instead
1565 of queues of objects. SLUB can use memory efficiently
1566 and has enhanced diagnostics. SLUB is the default choice for
1571 bool "SLOB (Simple Allocator)"
1573 SLOB replaces the stock allocator with a drastically simpler
1574 allocator. SLOB is generally more space efficient but
1575 does not perform as well on large systems.
1579 config MMAP_ALLOW_UNINITIALIZED
1580 bool "Allow mmapped anonymous memory to be uninitialized"
1581 depends on EXPERT && !MMU
1584 Normally, and according to the Linux spec, anonymous memory obtained
1585 from mmap() has it's contents cleared before it is passed to
1586 userspace. Enabling this config option allows you to request that
1587 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1588 providing a huge performance boost. If this option is not enabled,
1589 then the flag will be ignored.
1591 This is taken advantage of by uClibc's malloc(), and also by
1592 ELF-FDPIC binfmt's brk and stack allocator.
1594 Because of the obvious security issues, this option should only be
1595 enabled on embedded devices where you control what is run in
1596 userspace. Since that isn't generally a problem on no-MMU systems,
1597 it is normally safe to say Y here.
1599 See Documentation/nommu-mmap.txt for more information.
1602 bool "Profiling support"
1604 Say Y here to enable the extended profiling support mechanisms used
1605 by profilers such as OProfile.
1608 # Place an empty function call at each tracepoint site. Can be
1609 # dynamically changed for a probe function.
1614 source "arch/Kconfig"
1616 endmenu # General setup
1618 config HAVE_GENERIC_DMA_COHERENT
1625 depends on SLAB || SLUB_DEBUG
1633 default 0 if BASE_FULL
1634 default 1 if !BASE_FULL
1637 bool "Enable loadable module support"
1639 Kernel modules are small pieces of compiled code which can
1640 be inserted in the running kernel, rather than being
1641 permanently built into the kernel. You use the "modprobe"
1642 tool to add (and sometimes remove) them. If you say Y here,
1643 many parts of the kernel can be built as modules (by
1644 answering M instead of Y where indicated): this is most
1645 useful for infrequently used options which are not required
1646 for booting. For more information, see the man pages for
1647 modprobe, lsmod, modinfo, insmod and rmmod.
1649 If you say Y here, you will need to run "make
1650 modules_install" to put the modules under /lib/modules/
1651 where modprobe can find them (you may need to be root to do
1658 config MODULE_FORCE_LOAD
1659 bool "Forced module loading"
1662 Allow loading of modules without version information (ie. modprobe
1663 --force). Forced module loading sets the 'F' (forced) taint flag and
1664 is usually a really bad idea.
1666 config MODULE_UNLOAD
1667 bool "Module unloading"
1669 Without this option you will not be able to unload any
1670 modules (note that some modules may not be unloadable
1671 anyway), which makes your kernel smaller, faster
1672 and simpler. If unsure, say Y.
1674 config MODULE_FORCE_UNLOAD
1675 bool "Forced module unloading"
1676 depends on MODULE_UNLOAD
1678 This option allows you to force a module to unload, even if the
1679 kernel believes it is unsafe: the kernel will remove the module
1680 without waiting for anyone to stop using it (using the -f option to
1681 rmmod). This is mainly for kernel developers and desperate users.
1685 bool "Module versioning support"
1687 Usually, you have to use modules compiled with your kernel.
1688 Saying Y here makes it sometimes possible to use modules
1689 compiled for different kernels, by adding enough information
1690 to the modules to (hopefully) spot any changes which would
1691 make them incompatible with the kernel you are running. If
1694 config MODULE_SRCVERSION_ALL
1695 bool "Source checksum for all modules"
1697 Modules which contain a MODULE_VERSION get an extra "srcversion"
1698 field inserted into their modinfo section, which contains a
1699 sum of the source files which made it. This helps maintainers
1700 see exactly which source was used to build a module (since
1701 others sometimes change the module source without updating
1702 the version). With this option, such a "srcversion" field
1703 will be created for all modules. If unsure, say N.
1706 bool "Module signature verification"
1710 select ASYMMETRIC_KEY_TYPE
1711 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1712 select PUBLIC_KEY_ALGO_RSA
1715 select X509_CERTIFICATE_PARSER
1717 Check modules for valid signatures upon load: the signature
1718 is simply appended to the module. For more information see
1719 Documentation/module-signing.txt.
1721 !!!WARNING!!! If you enable this option, you MUST make sure that the
1722 module DOES NOT get stripped after being signed. This includes the
1723 debuginfo strip done by some packagers (such as rpmbuild) and
1724 inclusion into an initramfs that wants the module size reduced.
1726 config MODULE_SIG_FORCE
1727 bool "Require modules to be validly signed"
1728 depends on MODULE_SIG
1730 Reject unsigned modules or signed modules for which we don't have a
1731 key. Without this, such modules will simply taint the kernel.
1733 config MODULE_SIG_ALL
1734 bool "Automatically sign all modules"
1736 depends on MODULE_SIG
1738 Sign all modules during make modules_install. Without this option,
1739 modules must be signed manually, using the scripts/sign-file tool.
1741 comment "Do not forget to sign required modules with scripts/sign-file"
1742 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1745 prompt "Which hash algorithm should modules be signed with?"
1746 depends on MODULE_SIG
1748 This determines which sort of hashing algorithm will be used during
1749 signature generation. This algorithm _must_ be built into the kernel
1750 directly so that signature verification can take place. It is not
1751 possible to load a signed module containing the algorithm to check
1752 the signature on that module.
1754 config MODULE_SIG_SHA1
1755 bool "Sign modules with SHA-1"
1758 config MODULE_SIG_SHA224
1759 bool "Sign modules with SHA-224"
1760 select CRYPTO_SHA256
1762 config MODULE_SIG_SHA256
1763 bool "Sign modules with SHA-256"
1764 select CRYPTO_SHA256
1766 config MODULE_SIG_SHA384
1767 bool "Sign modules with SHA-384"
1768 select CRYPTO_SHA512
1770 config MODULE_SIG_SHA512
1771 bool "Sign modules with SHA-512"
1772 select CRYPTO_SHA512
1776 config MODULE_SIG_HASH
1778 depends on MODULE_SIG
1779 default "sha1" if MODULE_SIG_SHA1
1780 default "sha224" if MODULE_SIG_SHA224
1781 default "sha256" if MODULE_SIG_SHA256
1782 default "sha384" if MODULE_SIG_SHA384
1783 default "sha512" if MODULE_SIG_SHA512
1787 config INIT_ALL_POSSIBLE
1790 Back when each arch used to define their own cpu_online_mask and
1791 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1792 with all 1s, and others with all 0s. When they were centralised,
1793 it was better to provide this option than to break all the archs
1794 and have several arch maintainers pursuing me down dark alleys.
1799 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1801 Need stop_machine() primitive.
1803 source "block/Kconfig"
1805 config PREEMPT_NOTIFIERS
1812 # Can be selected by architectures with broken toolchains
1813 # that get confused by correct const<->read_only section
1815 config BROKEN_RODATA
1821 Build a simple ASN.1 grammar compiler that produces a bytecode output
1822 that can be interpreted by the ASN.1 stream decoder and used to
1823 inform it as to what tags are to be expected in a stream and what
1824 functions to call on what tags.
1826 source "kernel/Kconfig.locks"
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