7 option env="KERNELVERSION"
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
16 default "$ARCH_DEFCONFIG"
17 default "arch/$ARCH/defconfig"
26 config BUILDTIME_EXTABLE_SORT
36 depends on BROKEN || !SMP
39 config INIT_ENV_ARG_LIMIT
44 Maximum of each of the number of arguments and environment
45 variables passed to init from the kernel command line.
49 string "Cross-compiler tool prefix"
51 Same as running 'make CROSS_COMPILE=prefix-' but stored for
52 default make runs in this kernel build directory. You don't
53 need to set this unless you want the configured kernel build
54 directory to select the cross-compiler automatically.
57 bool "Compile also drivers which will not load"
60 Some drivers can be compiled on a different platform than they are
61 intended to be run on. Despite they cannot be loaded there (or even
62 when they load they cannot be used due to missing HW support),
63 developers still, opposing to distributors, might want to build such
64 drivers to compile-test them.
66 If you are a developer and want to build everything available, say Y
67 here. If you are a user/distributor, say N here to exclude useless
68 drivers to be distributed.
71 string "Local version - append to kernel release"
73 Append an extra string to the end of your kernel version.
74 This will show up when you type uname, for example.
75 The string you set here will be appended after the contents of
76 any files with a filename matching localversion* in your
77 object and source tree, in that order. Your total string can
78 be a maximum of 64 characters.
80 config LOCALVERSION_AUTO
81 bool "Automatically append version information to the version string"
84 This will try to automatically determine if the current tree is a
85 release tree by looking for git tags that belong to the current
88 A string of the format -gxxxxxxxx will be added to the localversion
89 if a git-based tree is found. The string generated by this will be
90 appended after any matching localversion* files, and after the value
91 set in CONFIG_LOCALVERSION.
93 (The actual string used here is the first eight characters produced
94 by running the command:
96 $ git rev-parse --verify HEAD
98 which is done within the script "scripts/setlocalversion".)
100 config HAVE_KERNEL_GZIP
103 config HAVE_KERNEL_BZIP2
106 config HAVE_KERNEL_LZMA
109 config HAVE_KERNEL_XZ
112 config HAVE_KERNEL_LZO
115 config HAVE_KERNEL_LZ4
119 prompt "Kernel compression mode"
121 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
123 The linux kernel is a kind of self-extracting executable.
124 Several compression algorithms are available, which differ
125 in efficiency, compression and decompression speed.
126 Compression speed is only relevant when building a kernel.
127 Decompression speed is relevant at each boot.
129 If you have any problems with bzip2 or lzma compressed
130 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
131 version of this functionality (bzip2 only), for 2.4, was
132 supplied by Christian Ludwig)
134 High compression options are mostly useful for users, who
135 are low on disk space (embedded systems), but for whom ram
138 If in doubt, select 'gzip'
142 depends on HAVE_KERNEL_GZIP
144 The old and tried gzip compression. It provides a good balance
145 between compression ratio and decompression speed.
149 depends on HAVE_KERNEL_BZIP2
151 Its compression ratio and speed is intermediate.
152 Decompression speed is slowest among the choices. The kernel
153 size is about 10% smaller with bzip2, in comparison to gzip.
154 Bzip2 uses a large amount of memory. For modern kernels you
155 will need at least 8MB RAM or more for booting.
159 depends on HAVE_KERNEL_LZMA
161 This compression algorithm's ratio is best. Decompression speed
162 is between gzip and bzip2. Compression is slowest.
163 The kernel size is about 33% smaller with LZMA in comparison to gzip.
167 depends on HAVE_KERNEL_XZ
169 XZ uses the LZMA2 algorithm and instruction set specific
170 BCJ filters which can improve compression ratio of executable
171 code. The size of the kernel is about 30% smaller with XZ in
172 comparison to gzip. On architectures for which there is a BCJ
173 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
174 will create a few percent smaller kernel than plain LZMA.
176 The speed is about the same as with LZMA: The decompression
177 speed of XZ is better than that of bzip2 but worse than gzip
178 and LZO. Compression is slow.
182 depends on HAVE_KERNEL_LZO
184 Its compression ratio is the poorest among the choices. The kernel
185 size is about 10% bigger than gzip; however its speed
186 (both compression and decompression) is the fastest.
190 depends on HAVE_KERNEL_LZ4
192 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
193 A preliminary version of LZ4 de/compression tool is available at
194 <https://code.google.com/p/lz4/>.
196 Its compression ratio is worse than LZO. The size of the kernel
197 is about 8% bigger than LZO. But the decompression speed is
202 config DEFAULT_HOSTNAME
203 string "Default hostname"
206 This option determines the default system hostname before userspace
207 calls sethostname(2). The kernel traditionally uses "(none)" here,
208 but you may wish to use a different default here to make a minimal
209 system more usable with less configuration.
212 bool "Support for paging of anonymous memory (swap)"
213 depends on MMU && BLOCK
216 This option allows you to choose whether you want to have support
217 for so called swap devices or swap files in your kernel that are
218 used to provide more virtual memory than the actual RAM present
219 in your computer. If unsure say Y.
224 Inter Process Communication is a suite of library functions and
225 system calls which let processes (running programs) synchronize and
226 exchange information. It is generally considered to be a good thing,
227 and some programs won't run unless you say Y here. In particular, if
228 you want to run the DOS emulator dosemu under Linux (read the
229 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
230 you'll need to say Y here.
232 You can find documentation about IPC with "info ipc" and also in
233 section 6.4 of the Linux Programmer's Guide, available from
234 <http://www.tldp.org/guides.html>.
236 config SYSVIPC_SYSCTL
243 bool "POSIX Message Queues"
246 POSIX variant of message queues is a part of IPC. In POSIX message
247 queues every message has a priority which decides about succession
248 of receiving it by a process. If you want to compile and run
249 programs written e.g. for Solaris with use of its POSIX message
250 queues (functions mq_*) say Y here.
252 POSIX message queues are visible as a filesystem called 'mqueue'
253 and can be mounted somewhere if you want to do filesystem
254 operations on message queues.
258 config POSIX_MQUEUE_SYSCTL
260 depends on POSIX_MQUEUE
265 bool "open by fhandle syscalls"
268 If you say Y here, a user level program will be able to map
269 file names to handle and then later use the handle for
270 different file system operations. This is useful in implementing
271 userspace file servers, which now track files using handles instead
272 of names. The handle would remain the same even if file names
273 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
277 bool "Auditing support"
280 Enable auditing infrastructure that can be used with another
281 kernel subsystem, such as SELinux (which requires this for
282 logging of avc messages output). Does not do system-call
283 auditing without CONFIG_AUDITSYSCALL.
286 bool "Enable system-call auditing support"
287 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
288 default y if SECURITY_SELINUX
290 Enable low-overhead system-call auditing infrastructure that
291 can be used independently or with another kernel subsystem,
296 depends on AUDITSYSCALL
301 depends on AUDITSYSCALL
304 source "kernel/irq/Kconfig"
305 source "kernel/time/Kconfig"
307 menu "CPU/Task time and stats accounting"
309 config VIRT_CPU_ACCOUNTING
313 prompt "Cputime accounting"
314 default TICK_CPU_ACCOUNTING if !PPC64
315 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
317 # Kind of a stub config for the pure tick based cputime accounting
318 config TICK_CPU_ACCOUNTING
319 bool "Simple tick based cputime accounting"
320 depends on !S390 && !NO_HZ_FULL
322 This is the basic tick based cputime accounting that maintains
323 statistics about user, system and idle time spent on per jiffies
328 config VIRT_CPU_ACCOUNTING_NATIVE
329 bool "Deterministic task and CPU time accounting"
330 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
331 select VIRT_CPU_ACCOUNTING
333 Select this option to enable more accurate task and CPU time
334 accounting. This is done by reading a CPU counter on each
335 kernel entry and exit and on transitions within the kernel
336 between system, softirq and hardirq state, so there is a
337 small performance impact. In the case of s390 or IBM POWER > 5,
338 this also enables accounting of stolen time on logically-partitioned
341 config VIRT_CPU_ACCOUNTING_GEN
342 bool "Full dynticks CPU time accounting"
343 depends on HAVE_CONTEXT_TRACKING && 64BIT
344 select VIRT_CPU_ACCOUNTING
345 select CONTEXT_TRACKING
347 Select this option to enable task and CPU time accounting on full
348 dynticks systems. This accounting is implemented by watching every
349 kernel-user boundaries using the context tracking subsystem.
350 The accounting is thus performed at the expense of some significant
353 For now this is only useful if you are working on the full
354 dynticks subsystem development.
358 config IRQ_TIME_ACCOUNTING
359 bool "Fine granularity task level IRQ time accounting"
360 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
362 Select this option to enable fine granularity task irq time
363 accounting. This is done by reading a timestamp on each
364 transitions between softirq and hardirq state, so there can be a
365 small performance impact.
367 If in doubt, say N here.
371 config BSD_PROCESS_ACCT
372 bool "BSD Process Accounting"
374 If you say Y here, a user level program will be able to instruct the
375 kernel (via a special system call) to write process accounting
376 information to a file: whenever a process exits, information about
377 that process will be appended to the file by the kernel. The
378 information includes things such as creation time, owning user,
379 command name, memory usage, controlling terminal etc. (the complete
380 list is in the struct acct in <file:include/linux/acct.h>). It is
381 up to the user level program to do useful things with this
382 information. This is generally a good idea, so say Y.
384 config BSD_PROCESS_ACCT_V3
385 bool "BSD Process Accounting version 3 file format"
386 depends on BSD_PROCESS_ACCT
389 If you say Y here, the process accounting information is written
390 in a new file format that also logs the process IDs of each
391 process and it's parent. Note that this file format is incompatible
392 with previous v0/v1/v2 file formats, so you will need updated tools
393 for processing it. A preliminary version of these tools is available
394 at <http://www.gnu.org/software/acct/>.
397 bool "Export task/process statistics through netlink"
401 Export selected statistics for tasks/processes through the
402 generic netlink interface. Unlike BSD process accounting, the
403 statistics are available during the lifetime of tasks/processes as
404 responses to commands. Like BSD accounting, they are sent to user
409 config TASK_DELAY_ACCT
410 bool "Enable per-task delay accounting"
413 Collect information on time spent by a task waiting for system
414 resources like cpu, synchronous block I/O completion and swapping
415 in pages. Such statistics can help in setting a task's priorities
416 relative to other tasks for cpu, io, rss limits etc.
421 bool "Enable extended accounting over taskstats"
424 Collect extended task accounting data and send the data
425 to userland for processing over the taskstats interface.
429 config TASK_IO_ACCOUNTING
430 bool "Enable per-task storage I/O accounting"
431 depends on TASK_XACCT
433 Collect information on the number of bytes of storage I/O which this
438 endmenu # "CPU/Task time and stats accounting"
443 prompt "RCU Implementation"
447 bool "Tree-based hierarchical RCU"
448 depends on !PREEMPT && SMP
451 This option selects the RCU implementation that is
452 designed for very large SMP system with hundreds or
453 thousands of CPUs. It also scales down nicely to
456 config TREE_PREEMPT_RCU
457 bool "Preemptible tree-based hierarchical RCU"
460 This option selects the RCU implementation that is
461 designed for very large SMP systems with hundreds or
462 thousands of CPUs, but for which real-time response
463 is also required. It also scales down nicely to
466 Select this option if you are unsure.
469 bool "UP-only small-memory-footprint RCU"
470 depends on !PREEMPT && !SMP
472 This option selects the RCU implementation that is
473 designed for UP systems from which real-time response
474 is not required. This option greatly reduces the
475 memory footprint of RCU.
480 def_bool TREE_PREEMPT_RCU
482 This option enables preemptible-RCU code that is common between
483 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
485 config RCU_STALL_COMMON
486 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
488 This option enables RCU CPU stall code that is common between
489 the TINY and TREE variants of RCU. The purpose is to allow
490 the tiny variants to disable RCU CPU stall warnings, while
491 making these warnings mandatory for the tree variants.
493 config CONTEXT_TRACKING
497 bool "Consider userspace as in RCU extended quiescent state"
498 depends on HAVE_CONTEXT_TRACKING && SMP
499 select CONTEXT_TRACKING
501 This option sets hooks on kernel / userspace boundaries and
502 puts RCU in extended quiescent state when the CPU runs in
503 userspace. It means that when a CPU runs in userspace, it is
504 excluded from the global RCU state machine and thus doesn't
505 try to keep the timer tick on for RCU.
507 Unless you want to hack and help the development of the full
508 dynticks mode, you shouldn't enable this option. It also
509 adds unnecessary overhead.
513 config CONTEXT_TRACKING_FORCE
514 bool "Force context tracking"
515 depends on CONTEXT_TRACKING
516 default CONTEXT_TRACKING
518 Probe on user/kernel boundaries by default in order to
519 test the features that rely on it such as userspace RCU extended
521 This test is there for debugging until we have a real user like the
525 int "Tree-based hierarchical RCU fanout value"
528 depends on TREE_RCU || TREE_PREEMPT_RCU
532 This option controls the fanout of hierarchical implementations
533 of RCU, allowing RCU to work efficiently on machines with
534 large numbers of CPUs. This value must be at least the fourth
535 root of NR_CPUS, which allows NR_CPUS to be insanely large.
536 The default value of RCU_FANOUT should be used for production
537 systems, but if you are stress-testing the RCU implementation
538 itself, small RCU_FANOUT values allow you to test large-system
539 code paths on small(er) systems.
541 Select a specific number if testing RCU itself.
542 Take the default if unsure.
544 config RCU_FANOUT_LEAF
545 int "Tree-based hierarchical RCU leaf-level fanout value"
546 range 2 RCU_FANOUT if 64BIT
547 range 2 RCU_FANOUT if !64BIT
548 depends on TREE_RCU || TREE_PREEMPT_RCU
551 This option controls the leaf-level fanout of hierarchical
552 implementations of RCU, and allows trading off cache misses
553 against lock contention. Systems that synchronize their
554 scheduling-clock interrupts for energy-efficiency reasons will
555 want the default because the smaller leaf-level fanout keeps
556 lock contention levels acceptably low. Very large systems
557 (hundreds or thousands of CPUs) will instead want to set this
558 value to the maximum value possible in order to reduce the
559 number of cache misses incurred during RCU's grace-period
560 initialization. These systems tend to run CPU-bound, and thus
561 are not helped by synchronized interrupts, and thus tend to
562 skew them, which reduces lock contention enough that large
563 leaf-level fanouts work well.
565 Select a specific number if testing RCU itself.
567 Select the maximum permissible value for large systems.
569 Take the default if unsure.
571 config RCU_FANOUT_EXACT
572 bool "Disable tree-based hierarchical RCU auto-balancing"
573 depends on TREE_RCU || TREE_PREEMPT_RCU
576 This option forces use of the exact RCU_FANOUT value specified,
577 regardless of imbalances in the hierarchy. This is useful for
578 testing RCU itself, and might one day be useful on systems with
579 strong NUMA behavior.
581 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
585 config RCU_FAST_NO_HZ
586 bool "Accelerate last non-dyntick-idle CPU's grace periods"
587 depends on NO_HZ_COMMON && SMP
590 This option permits CPUs to enter dynticks-idle state even if
591 they have RCU callbacks queued, and prevents RCU from waking
592 these CPUs up more than roughly once every four jiffies (by
593 default, you can adjust this using the rcutree.rcu_idle_gp_delay
594 parameter), thus improving energy efficiency. On the other
595 hand, this option increases the duration of RCU grace periods,
596 for example, slowing down synchronize_rcu().
598 Say Y if energy efficiency is critically important, and you
599 don't care about increased grace-period durations.
601 Say N if you are unsure.
603 config TREE_RCU_TRACE
604 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
607 This option provides tracing for the TREE_RCU and
608 TREE_PREEMPT_RCU implementations, permitting Makefile to
609 trivially select kernel/rcutree_trace.c.
612 bool "Enable RCU priority boosting"
613 depends on RT_MUTEXES && PREEMPT_RCU
616 This option boosts the priority of preempted RCU readers that
617 block the current preemptible RCU grace period for too long.
618 This option also prevents heavy loads from blocking RCU
619 callback invocation for all flavors of RCU.
621 Say Y here if you are working with real-time apps or heavy loads
622 Say N here if you are unsure.
624 config RCU_BOOST_PRIO
625 int "Real-time priority to boost RCU readers to"
630 This option specifies the real-time priority to which long-term
631 preempted RCU readers are to be boosted. If you are working
632 with a real-time application that has one or more CPU-bound
633 threads running at a real-time priority level, you should set
634 RCU_BOOST_PRIO to a priority higher then the highest-priority
635 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
636 of 1 is appropriate in the common case, which is real-time
637 applications that do not have any CPU-bound threads.
639 Some real-time applications might not have a single real-time
640 thread that saturates a given CPU, but instead might have
641 multiple real-time threads that, taken together, fully utilize
642 that CPU. In this case, you should set RCU_BOOST_PRIO to
643 a priority higher than the lowest-priority thread that is
644 conspiring to prevent the CPU from running any non-real-time
645 tasks. For example, if one thread at priority 10 and another
646 thread at priority 5 are between themselves fully consuming
647 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
648 set to priority 6 or higher.
650 Specify the real-time priority, or take the default if unsure.
652 config RCU_BOOST_DELAY
653 int "Milliseconds to delay boosting after RCU grace-period start"
658 This option specifies the time to wait after the beginning of
659 a given grace period before priority-boosting preempted RCU
660 readers blocking that grace period. Note that any RCU reader
661 blocking an expedited RCU grace period is boosted immediately.
663 Accept the default if unsure.
666 bool "Offload RCU callback processing from boot-selected CPUs"
667 depends on TREE_RCU || TREE_PREEMPT_RCU
670 Use this option to reduce OS jitter for aggressive HPC or
671 real-time workloads. It can also be used to offload RCU
672 callback invocation to energy-efficient CPUs in battery-powered
673 asymmetric multiprocessors.
675 This option offloads callback invocation from the set of
676 CPUs specified at boot time by the rcu_nocbs parameter.
677 For each such CPU, a kthread ("rcuox/N") will be created to
678 invoke callbacks, where the "N" is the CPU being offloaded,
679 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
680 "s" for RCU-sched. Nothing prevents this kthread from running
681 on the specified CPUs, but (1) the kthreads may be preempted
682 between each callback, and (2) affinity or cgroups can be used
683 to force the kthreads to run on whatever set of CPUs is desired.
685 Say Y here if you want to help to debug reduced OS jitter.
686 Say N here if you are unsure.
689 prompt "Build-forced no-CBs CPUs"
690 default RCU_NOCB_CPU_NONE
692 This option allows no-CBs CPUs (whose RCU callbacks are invoked
693 from kthreads rather than from softirq context) to be specified
694 at build time. Additional no-CBs CPUs may be specified by
695 the rcu_nocbs= boot parameter.
697 config RCU_NOCB_CPU_NONE
698 bool "No build_forced no-CBs CPUs"
699 depends on RCU_NOCB_CPU && !NO_HZ_FULL
701 This option does not force any of the CPUs to be no-CBs CPUs.
702 Only CPUs designated by the rcu_nocbs= boot parameter will be
703 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
704 kthreads whose names begin with "rcuo". All other CPUs will
705 invoke their own RCU callbacks in softirq context.
707 Select this option if you want to choose no-CBs CPUs at
708 boot time, for example, to allow testing of different no-CBs
709 configurations without having to rebuild the kernel each time.
711 config RCU_NOCB_CPU_ZERO
712 bool "CPU 0 is a build_forced no-CBs CPU"
713 depends on RCU_NOCB_CPU && !NO_HZ_FULL
715 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
716 callbacks are invoked by a per-CPU kthread whose name begins
717 with "rcuo". Additional CPUs may be designated as no-CBs
718 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
719 All other CPUs will invoke their own RCU callbacks in softirq
722 Select this if CPU 0 needs to be a no-CBs CPU for real-time
723 or energy-efficiency reasons, but the real reason it exists
724 is to ensure that randconfig testing covers mixed systems.
726 config RCU_NOCB_CPU_ALL
727 bool "All CPUs are build_forced no-CBs CPUs"
728 depends on RCU_NOCB_CPU
730 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
731 boot parameter will be ignored. All CPUs' RCU callbacks will
732 be executed in the context of per-CPU rcuo kthreads created for
733 this purpose. Assuming that the kthreads whose names start with
734 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
735 on the remaining CPUs, but might decrease memory locality during
736 RCU-callback invocation, thus potentially degrading throughput.
738 Select this if all CPUs need to be no-CBs CPUs for real-time
739 or energy-efficiency reasons.
743 endmenu # "RCU Subsystem"
746 tristate "Kernel .config support"
748 This option enables the complete Linux kernel ".config" file
749 contents to be saved in the kernel. It provides documentation
750 of which kernel options are used in a running kernel or in an
751 on-disk kernel. This information can be extracted from the kernel
752 image file with the script scripts/extract-ikconfig and used as
753 input to rebuild the current kernel or to build another kernel.
754 It can also be extracted from a running kernel by reading
755 /proc/config.gz if enabled (below).
758 bool "Enable access to .config through /proc/config.gz"
759 depends on IKCONFIG && PROC_FS
761 This option enables access to the kernel configuration file
762 through /proc/config.gz.
765 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
769 Select kernel log buffer size as a power of 2.
779 # Architectures with an unreliable sched_clock() should select this:
781 config HAVE_UNSTABLE_SCHED_CLOCK
784 config GENERIC_SCHED_CLOCK
788 # For architectures that want to enable the support for NUMA-affine scheduler
791 config ARCH_SUPPORTS_NUMA_BALANCING
794 # For architectures that (ab)use NUMA to represent different memory regions
795 # all cpu-local but of different latencies, such as SuperH.
797 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
801 # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
802 config ARCH_WANTS_PROT_NUMA_PROT_NONE
805 config ARCH_USES_NUMA_PROT_NONE
808 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
809 depends on NUMA_BALANCING
811 config NUMA_BALANCING_DEFAULT_ENABLED
812 bool "Automatically enable NUMA aware memory/task placement"
814 depends on NUMA_BALANCING
816 If set, autonumic NUMA balancing will be enabled if running on a NUMA
819 config NUMA_BALANCING
820 bool "Memory placement aware NUMA scheduler"
821 depends on ARCH_SUPPORTS_NUMA_BALANCING
822 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
823 depends on SMP && NUMA && MIGRATION
825 This option adds support for automatic NUMA aware memory/task placement.
826 The mechanism is quite primitive and is based on migrating memory when
827 it is references to the node the task is running on.
829 This system will be inactive on UMA systems.
832 boolean "Control Group support"
835 This option adds support for grouping sets of processes together, for
836 use with process control subsystems such as Cpusets, CFS, memory
837 controls or device isolation.
839 - Documentation/scheduler/sched-design-CFS.txt (CFS)
840 - Documentation/cgroups/ (features for grouping, isolation
841 and resource control)
848 bool "Example debug cgroup subsystem"
851 This option enables a simple cgroup subsystem that
852 exports useful debugging information about the cgroups
857 config CGROUP_FREEZER
858 bool "Freezer cgroup subsystem"
860 Provides a way to freeze and unfreeze all tasks in a
864 bool "Device controller for cgroups"
866 Provides a cgroup implementing whitelists for devices which
867 a process in the cgroup can mknod or open.
870 bool "Cpuset support"
872 This option will let you create and manage CPUSETs which
873 allow dynamically partitioning a system into sets of CPUs and
874 Memory Nodes and assigning tasks to run only within those sets.
875 This is primarily useful on large SMP or NUMA systems.
879 config PROC_PID_CPUSET
880 bool "Include legacy /proc/<pid>/cpuset file"
884 config CGROUP_CPUACCT
885 bool "Simple CPU accounting cgroup subsystem"
887 Provides a simple Resource Controller for monitoring the
888 total CPU consumed by the tasks in a cgroup.
890 config RESOURCE_COUNTERS
891 bool "Resource counters"
893 This option enables controller independent resource accounting
894 infrastructure that works with cgroups.
897 bool "Memory Resource Controller for Control Groups"
898 depends on RESOURCE_COUNTERS
901 Provides a memory resource controller that manages both anonymous
902 memory and page cache. (See Documentation/cgroups/memory.txt)
904 Note that setting this option increases fixed memory overhead
905 associated with each page of memory in the system. By this,
906 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
907 usage tracking struct at boot. Total amount of this is printed out
910 Only enable when you're ok with these trade offs and really
911 sure you need the memory resource controller. Even when you enable
912 this, you can set "cgroup_disable=memory" at your boot option to
913 disable memory resource controller and you can avoid overheads.
914 (and lose benefits of memory resource controller)
916 This config option also selects MM_OWNER config option, which
917 could in turn add some fork/exit overhead.
920 bool "Memory Resource Controller Swap Extension"
921 depends on MEMCG && SWAP
923 Add swap management feature to memory resource controller. When you
924 enable this, you can limit mem+swap usage per cgroup. In other words,
925 when you disable this, memory resource controller has no cares to
926 usage of swap...a process can exhaust all of the swap. This extension
927 is useful when you want to avoid exhaustion swap but this itself
928 adds more overheads and consumes memory for remembering information.
929 Especially if you use 32bit system or small memory system, please
930 be careful about enabling this. When memory resource controller
931 is disabled by boot option, this will be automatically disabled and
932 there will be no overhead from this. Even when you set this config=y,
933 if boot option "swapaccount=0" is set, swap will not be accounted.
934 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
935 size is 4096bytes, 512k per 1Gbytes of swap.
936 config MEMCG_SWAP_ENABLED
937 bool "Memory Resource Controller Swap Extension enabled by default"
938 depends on MEMCG_SWAP
941 Memory Resource Controller Swap Extension comes with its price in
942 a bigger memory consumption. General purpose distribution kernels
943 which want to enable the feature but keep it disabled by default
944 and let the user enable it by swapaccount=1 boot command line
945 parameter should have this option unselected.
946 For those who want to have the feature enabled by default should
947 select this option (if, for some reason, they need to disable it
948 then swapaccount=0 does the trick).
950 bool "Memory Resource Controller Kernel Memory accounting"
952 depends on SLUB || SLAB
954 The Kernel Memory extension for Memory Resource Controller can limit
955 the amount of memory used by kernel objects in the system. Those are
956 fundamentally different from the entities handled by the standard
957 Memory Controller, which are page-based, and can be swapped. Users of
958 the kmem extension can use it to guarantee that no group of processes
959 will ever exhaust kernel resources alone.
961 config CGROUP_HUGETLB
962 bool "HugeTLB Resource Controller for Control Groups"
963 depends on RESOURCE_COUNTERS && HUGETLB_PAGE
966 Provides a cgroup Resource Controller for HugeTLB pages.
967 When you enable this, you can put a per cgroup limit on HugeTLB usage.
968 The limit is enforced during page fault. Since HugeTLB doesn't
969 support page reclaim, enforcing the limit at page fault time implies
970 that, the application will get SIGBUS signal if it tries to access
971 HugeTLB pages beyond its limit. This requires the application to know
972 beforehand how much HugeTLB pages it would require for its use. The
973 control group is tracked in the third page lru pointer. This means
974 that we cannot use the controller with huge page less than 3 pages.
977 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
978 depends on PERF_EVENTS && CGROUPS
980 This option extends the per-cpu mode to restrict monitoring to
981 threads which belong to the cgroup specified and run on the
986 menuconfig CGROUP_SCHED
987 bool "Group CPU scheduler"
990 This feature lets CPU scheduler recognize task groups and control CPU
991 bandwidth allocation to such task groups. It uses cgroups to group
995 config FAIR_GROUP_SCHED
996 bool "Group scheduling for SCHED_OTHER"
997 depends on CGROUP_SCHED
1000 config CFS_BANDWIDTH
1001 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1002 depends on FAIR_GROUP_SCHED
1005 This option allows users to define CPU bandwidth rates (limits) for
1006 tasks running within the fair group scheduler. Groups with no limit
1007 set are considered to be unconstrained and will run with no
1009 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1011 config RT_GROUP_SCHED
1012 bool "Group scheduling for SCHED_RR/FIFO"
1013 depends on CGROUP_SCHED
1016 This feature lets you explicitly allocate real CPU bandwidth
1017 to task groups. If enabled, it will also make it impossible to
1018 schedule realtime tasks for non-root users until you allocate
1019 realtime bandwidth for them.
1020 See Documentation/scheduler/sched-rt-group.txt for more information.
1025 bool "Block IO controller"
1029 Generic block IO controller cgroup interface. This is the common
1030 cgroup interface which should be used by various IO controlling
1033 Currently, CFQ IO scheduler uses it to recognize task groups and
1034 control disk bandwidth allocation (proportional time slice allocation)
1035 to such task groups. It is also used by bio throttling logic in
1036 block layer to implement upper limit in IO rates on a device.
1038 This option only enables generic Block IO controller infrastructure.
1039 One needs to also enable actual IO controlling logic/policy. For
1040 enabling proportional weight division of disk bandwidth in CFQ, set
1041 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1042 CONFIG_BLK_DEV_THROTTLING=y.
1044 See Documentation/cgroups/blkio-controller.txt for more information.
1046 config DEBUG_BLK_CGROUP
1047 bool "Enable Block IO controller debugging"
1048 depends on BLK_CGROUP
1051 Enable some debugging help. Currently it exports additional stat
1052 files in a cgroup which can be useful for debugging.
1056 config CHECKPOINT_RESTORE
1057 bool "Checkpoint/restore support" if EXPERT
1060 Enables additional kernel features in a sake of checkpoint/restore.
1061 In particular it adds auxiliary prctl codes to setup process text,
1062 data and heap segment sizes, and a few additional /proc filesystem
1065 If unsure, say N here.
1067 menuconfig NAMESPACES
1068 bool "Namespaces support" if EXPERT
1071 Provides the way to make tasks work with different objects using
1072 the same id. For example same IPC id may refer to different objects
1073 or same user id or pid may refer to different tasks when used in
1074 different namespaces.
1079 bool "UTS namespace"
1082 In this namespace tasks see different info provided with the
1086 bool "IPC namespace"
1087 depends on (SYSVIPC || POSIX_MQUEUE)
1090 In this namespace tasks work with IPC ids which correspond to
1091 different IPC objects in different namespaces.
1094 bool "User namespace"
1095 depends on UIDGID_CONVERTED
1096 select UIDGID_STRICT_TYPE_CHECKS
1100 This allows containers, i.e. vservers, to use user namespaces
1101 to provide different user info for different servers.
1103 When user namespaces are enabled in the kernel it is
1104 recommended that the MEMCG and MEMCG_KMEM options also be
1105 enabled and that user-space use the memory control groups to
1106 limit the amount of memory a memory unprivileged users can
1112 bool "PID Namespaces"
1115 Support process id namespaces. This allows having multiple
1116 processes with the same pid as long as they are in different
1117 pid namespaces. This is a building block of containers.
1120 bool "Network namespace"
1124 Allow user space to create what appear to be multiple instances
1125 of the network stack.
1129 config UIDGID_CONVERTED
1130 # True if all of the selected software conmponents are known
1131 # to have uid_t and gid_t converted to kuid_t and kgid_t
1132 # where appropriate and are otherwise safe to use with
1133 # the user namespace.
1138 depends on XFS_FS = n
1140 config UIDGID_STRICT_TYPE_CHECKS
1141 bool "Require conversions between uid/gids and their internal representation"
1142 depends on UIDGID_CONVERTED
1145 While the nececessary conversions are being added to all subsystems this option allows
1146 the code to continue to build for unconverted subsystems.
1148 Say Y here if you want the strict type checking enabled
1150 config SCHED_AUTOGROUP
1151 bool "Automatic process group scheduling"
1155 select FAIR_GROUP_SCHED
1157 This option optimizes the scheduler for common desktop workloads by
1158 automatically creating and populating task groups. This separation
1159 of workloads isolates aggressive CPU burners (like build jobs) from
1160 desktop applications. Task group autogeneration is currently based
1166 config SYSFS_DEPRECATED
1167 bool "Enable deprecated sysfs features to support old userspace tools"
1171 This option adds code that switches the layout of the "block" class
1172 devices, to not show up in /sys/class/block/, but only in
1175 This switch is only active when the sysfs.deprecated=1 boot option is
1176 passed or the SYSFS_DEPRECATED_V2 option is set.
1178 This option allows new kernels to run on old distributions and tools,
1179 which might get confused by /sys/class/block/. Since 2007/2008 all
1180 major distributions and tools handle this just fine.
1182 Recent distributions and userspace tools after 2009/2010 depend on
1183 the existence of /sys/class/block/, and will not work with this
1186 Only if you are using a new kernel on an old distribution, you might
1189 config SYSFS_DEPRECATED_V2
1190 bool "Enable deprecated sysfs features by default"
1193 depends on SYSFS_DEPRECATED
1195 Enable deprecated sysfs by default.
1197 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1200 Only if you are using a new kernel on an old distribution, you might
1201 need to say Y here. Even then, odds are you would not need it
1202 enabled, you can always pass the boot option if absolutely necessary.
1205 bool "Kernel->user space relay support (formerly relayfs)"
1207 This option enables support for relay interface support in
1208 certain file systems (such as debugfs).
1209 It is designed to provide an efficient mechanism for tools and
1210 facilities to relay large amounts of data from kernel space to
1215 config BLK_DEV_INITRD
1216 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1217 depends on BROKEN || !FRV
1219 The initial RAM filesystem is a ramfs which is loaded by the
1220 boot loader (loadlin or lilo) and that is mounted as root
1221 before the normal boot procedure. It is typically used to
1222 load modules needed to mount the "real" root file system,
1223 etc. See <file:Documentation/initrd.txt> for details.
1225 If RAM disk support (BLK_DEV_RAM) is also included, this
1226 also enables initial RAM disk (initrd) support and adds
1227 15 Kbytes (more on some other architectures) to the kernel size.
1233 source "usr/Kconfig"
1237 config CC_OPTIMIZE_FOR_SIZE
1238 bool "Optimize for size"
1240 Enabling this option will pass "-Os" instead of "-O2" to gcc
1241 resulting in a smaller kernel.
1254 config SYSCTL_EXCEPTION_TRACE
1257 Enable support for /proc/sys/debug/exception-trace.
1259 config SYSCTL_ARCH_UNALIGN_NO_WARN
1262 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1263 Allows arch to define/use @no_unaligned_warning to possibly warn
1264 about unaligned access emulation going on under the hood.
1266 config SYSCTL_ARCH_UNALIGN_ALLOW
1269 Enable support for /proc/sys/kernel/unaligned-trap
1270 Allows arches to define/use @unaligned_enabled to runtime toggle
1271 the unaligned access emulation.
1272 see arch/parisc/kernel/unaligned.c for reference
1274 config HAVE_PCSPKR_PLATFORM
1278 bool "Configure standard kernel features (expert users)"
1279 # Unhide debug options, to make the on-by-default options visible
1282 This option allows certain base kernel options and settings
1283 to be disabled or tweaked. This is for specialized
1284 environments which can tolerate a "non-standard" kernel.
1285 Only use this if you really know what you are doing.
1288 bool "Enable 16-bit UID system calls" if EXPERT
1289 depends on HAVE_UID16
1292 This enables the legacy 16-bit UID syscall wrappers.
1294 config SYSCTL_SYSCALL
1295 bool "Sysctl syscall support" if EXPERT
1296 depends on PROC_SYSCTL
1300 sys_sysctl uses binary paths that have been found challenging
1301 to properly maintain and use. The interface in /proc/sys
1302 using paths with ascii names is now the primary path to this
1305 Almost nothing using the binary sysctl interface so if you are
1306 trying to save some space it is probably safe to disable this,
1307 making your kernel marginally smaller.
1309 If unsure say N here.
1312 bool "Load all symbols for debugging/ksymoops" if EXPERT
1315 Say Y here to let the kernel print out symbolic crash information and
1316 symbolic stack backtraces. This increases the size of the kernel
1317 somewhat, as all symbols have to be loaded into the kernel image.
1320 bool "Include all symbols in kallsyms"
1321 depends on DEBUG_KERNEL && KALLSYMS
1323 Normally kallsyms only contains the symbols of functions for nicer
1324 OOPS messages and backtraces (i.e., symbols from the text and inittext
1325 sections). This is sufficient for most cases. And only in very rare
1326 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1327 names of variables from the data sections, etc).
1329 This option makes sure that all symbols are loaded into the kernel
1330 image (i.e., symbols from all sections) in cost of increased kernel
1331 size (depending on the kernel configuration, it may be 300KiB or
1332 something like this).
1334 Say N unless you really need all symbols.
1338 bool "Enable support for printk" if EXPERT
1341 This option enables normal printk support. Removing it
1342 eliminates most of the message strings from the kernel image
1343 and makes the kernel more or less silent. As this makes it
1344 very difficult to diagnose system problems, saying N here is
1345 strongly discouraged.
1348 bool "BUG() support" if EXPERT
1351 Disabling this option eliminates support for BUG and WARN, reducing
1352 the size of your kernel image and potentially quietly ignoring
1353 numerous fatal conditions. You should only consider disabling this
1354 option for embedded systems with no facilities for reporting errors.
1360 bool "Enable ELF core dumps" if EXPERT
1362 Enable support for generating core dumps. Disabling saves about 4k.
1365 config PCSPKR_PLATFORM
1366 bool "Enable PC-Speaker support" if EXPERT
1367 depends on HAVE_PCSPKR_PLATFORM
1371 This option allows to disable the internal PC-Speaker
1372 support, saving some memory.
1376 bool "Enable full-sized data structures for core" if EXPERT
1378 Disabling this option reduces the size of miscellaneous core
1379 kernel data structures. This saves memory on small machines,
1380 but may reduce performance.
1383 bool "Enable futex support" if EXPERT
1387 Disabling this option will cause the kernel to be built without
1388 support for "fast userspace mutexes". The resulting kernel may not
1389 run glibc-based applications correctly.
1392 bool "Enable eventpoll support" if EXPERT
1396 Disabling this option will cause the kernel to be built without
1397 support for epoll family of system calls.
1400 bool "Enable signalfd() system call" if EXPERT
1404 Enable the signalfd() system call that allows to receive signals
1405 on a file descriptor.
1410 bool "Enable timerfd() system call" if EXPERT
1414 Enable the timerfd() system call that allows to receive timer
1415 events on a file descriptor.
1420 bool "Enable eventfd() system call" if EXPERT
1424 Enable the eventfd() system call that allows to receive both
1425 kernel notification (ie. KAIO) or userspace notifications.
1430 bool "Use full shmem filesystem" if EXPERT
1434 The shmem is an internal filesystem used to manage shared memory.
1435 It is backed by swap and manages resource limits. It is also exported
1436 to userspace as tmpfs if TMPFS is enabled. Disabling this
1437 option replaces shmem and tmpfs with the much simpler ramfs code,
1438 which may be appropriate on small systems without swap.
1441 bool "Enable AIO support" if EXPERT
1444 This option enables POSIX asynchronous I/O which may by used
1445 by some high performance threaded applications. Disabling
1446 this option saves about 7k.
1450 bool "Enable PCI quirk workarounds" if EXPERT
1453 This enables workarounds for various PCI chipset
1454 bugs/quirks. Disable this only if your target machine is
1455 unaffected by PCI quirks.
1458 bool "Embedded system"
1461 This option should be enabled if compiling the kernel for
1462 an embedded system so certain expert options are available
1465 config HAVE_PERF_EVENTS
1468 See tools/perf/design.txt for details.
1470 config PERF_USE_VMALLOC
1473 See tools/perf/design.txt for details
1475 menu "Kernel Performance Events And Counters"
1478 bool "Kernel performance events and counters"
1479 default y if PROFILING
1480 depends on HAVE_PERF_EVENTS
1484 Enable kernel support for various performance events provided
1485 by software and hardware.
1487 Software events are supported either built-in or via the
1488 use of generic tracepoints.
1490 Most modern CPUs support performance events via performance
1491 counter registers. These registers count the number of certain
1492 types of hw events: such as instructions executed, cachemisses
1493 suffered, or branches mis-predicted - without slowing down the
1494 kernel or applications. These registers can also trigger interrupts
1495 when a threshold number of events have passed - and can thus be
1496 used to profile the code that runs on that CPU.
1498 The Linux Performance Event subsystem provides an abstraction of
1499 these software and hardware event capabilities, available via a
1500 system call and used by the "perf" utility in tools/perf/. It
1501 provides per task and per CPU counters, and it provides event
1502 capabilities on top of those.
1506 config DEBUG_PERF_USE_VMALLOC
1508 bool "Debug: use vmalloc to back perf mmap() buffers"
1509 depends on PERF_EVENTS && DEBUG_KERNEL
1510 select PERF_USE_VMALLOC
1512 Use vmalloc memory to back perf mmap() buffers.
1514 Mostly useful for debugging the vmalloc code on platforms
1515 that don't require it.
1521 config VM_EVENT_COUNTERS
1523 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1525 VM event counters are needed for event counts to be shown.
1526 This option allows the disabling of the VM event counters
1527 on EXPERT systems. /proc/vmstat will only show page counts
1528 if VM event counters are disabled.
1532 bool "Enable SLUB debugging support" if EXPERT
1533 depends on SLUB && SYSFS
1535 SLUB has extensive debug support features. Disabling these can
1536 result in significant savings in code size. This also disables
1537 SLUB sysfs support. /sys/slab will not exist and there will be
1538 no support for cache validation etc.
1541 bool "Disable heap randomization"
1544 Randomizing heap placement makes heap exploits harder, but it
1545 also breaks ancient binaries (including anything libc5 based).
1546 This option changes the bootup default to heap randomization
1547 disabled, and can be overridden at runtime by setting
1548 /proc/sys/kernel/randomize_va_space to 2.
1550 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1553 prompt "Choose SLAB allocator"
1556 This option allows to select a slab allocator.
1561 The regular slab allocator that is established and known to work
1562 well in all environments. It organizes cache hot objects in
1563 per cpu and per node queues.
1566 bool "SLUB (Unqueued Allocator)"
1568 SLUB is a slab allocator that minimizes cache line usage
1569 instead of managing queues of cached objects (SLAB approach).
1570 Per cpu caching is realized using slabs of objects instead
1571 of queues of objects. SLUB can use memory efficiently
1572 and has enhanced diagnostics. SLUB is the default choice for
1577 bool "SLOB (Simple Allocator)"
1579 SLOB replaces the stock allocator with a drastically simpler
1580 allocator. SLOB is generally more space efficient but
1581 does not perform as well on large systems.
1585 config SLUB_CPU_PARTIAL
1588 bool "SLUB per cpu partial cache"
1590 Per cpu partial caches accellerate objects allocation and freeing
1591 that is local to a processor at the price of more indeterminism
1592 in the latency of the free. On overflow these caches will be cleared
1593 which requires the taking of locks that may cause latency spikes.
1594 Typically one would choose no for a realtime system.
1596 config MMAP_ALLOW_UNINITIALIZED
1597 bool "Allow mmapped anonymous memory to be uninitialized"
1598 depends on EXPERT && !MMU
1601 Normally, and according to the Linux spec, anonymous memory obtained
1602 from mmap() has it's contents cleared before it is passed to
1603 userspace. Enabling this config option allows you to request that
1604 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1605 providing a huge performance boost. If this option is not enabled,
1606 then the flag will be ignored.
1608 This is taken advantage of by uClibc's malloc(), and also by
1609 ELF-FDPIC binfmt's brk and stack allocator.
1611 Because of the obvious security issues, this option should only be
1612 enabled on embedded devices where you control what is run in
1613 userspace. Since that isn't generally a problem on no-MMU systems,
1614 it is normally safe to say Y here.
1616 See Documentation/nommu-mmap.txt for more information.
1619 bool "Profiling support"
1621 Say Y here to enable the extended profiling support mechanisms used
1622 by profilers such as OProfile.
1625 # Place an empty function call at each tracepoint site. Can be
1626 # dynamically changed for a probe function.
1631 source "arch/Kconfig"
1633 endmenu # General setup
1635 config HAVE_GENERIC_DMA_COHERENT
1642 depends on SLAB || SLUB_DEBUG
1650 default 0 if BASE_FULL
1651 default 1 if !BASE_FULL
1654 bool "Enable loadable module support"
1656 Kernel modules are small pieces of compiled code which can
1657 be inserted in the running kernel, rather than being
1658 permanently built into the kernel. You use the "modprobe"
1659 tool to add (and sometimes remove) them. If you say Y here,
1660 many parts of the kernel can be built as modules (by
1661 answering M instead of Y where indicated): this is most
1662 useful for infrequently used options which are not required
1663 for booting. For more information, see the man pages for
1664 modprobe, lsmod, modinfo, insmod and rmmod.
1666 If you say Y here, you will need to run "make
1667 modules_install" to put the modules under /lib/modules/
1668 where modprobe can find them (you may need to be root to do
1675 config MODULE_FORCE_LOAD
1676 bool "Forced module loading"
1679 Allow loading of modules without version information (ie. modprobe
1680 --force). Forced module loading sets the 'F' (forced) taint flag and
1681 is usually a really bad idea.
1683 config MODULE_UNLOAD
1684 bool "Module unloading"
1686 Without this option you will not be able to unload any
1687 modules (note that some modules may not be unloadable
1688 anyway), which makes your kernel smaller, faster
1689 and simpler. If unsure, say Y.
1691 config MODULE_FORCE_UNLOAD
1692 bool "Forced module unloading"
1693 depends on MODULE_UNLOAD
1695 This option allows you to force a module to unload, even if the
1696 kernel believes it is unsafe: the kernel will remove the module
1697 without waiting for anyone to stop using it (using the -f option to
1698 rmmod). This is mainly for kernel developers and desperate users.
1702 bool "Module versioning support"
1704 Usually, you have to use modules compiled with your kernel.
1705 Saying Y here makes it sometimes possible to use modules
1706 compiled for different kernels, by adding enough information
1707 to the modules to (hopefully) spot any changes which would
1708 make them incompatible with the kernel you are running. If
1711 config MODULE_SRCVERSION_ALL
1712 bool "Source checksum for all modules"
1714 Modules which contain a MODULE_VERSION get an extra "srcversion"
1715 field inserted into their modinfo section, which contains a
1716 sum of the source files which made it. This helps maintainers
1717 see exactly which source was used to build a module (since
1718 others sometimes change the module source without updating
1719 the version). With this option, such a "srcversion" field
1720 will be created for all modules. If unsure, say N.
1723 bool "Module signature verification"
1727 select ASYMMETRIC_KEY_TYPE
1728 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1729 select PUBLIC_KEY_ALGO_RSA
1732 select X509_CERTIFICATE_PARSER
1734 Check modules for valid signatures upon load: the signature
1735 is simply appended to the module. For more information see
1736 Documentation/module-signing.txt.
1738 !!!WARNING!!! If you enable this option, you MUST make sure that the
1739 module DOES NOT get stripped after being signed. This includes the
1740 debuginfo strip done by some packagers (such as rpmbuild) and
1741 inclusion into an initramfs that wants the module size reduced.
1743 config MODULE_SIG_FORCE
1744 bool "Require modules to be validly signed"
1745 depends on MODULE_SIG
1747 Reject unsigned modules or signed modules for which we don't have a
1748 key. Without this, such modules will simply taint the kernel.
1750 config MODULE_SIG_ALL
1751 bool "Automatically sign all modules"
1753 depends on MODULE_SIG
1755 Sign all modules during make modules_install. Without this option,
1756 modules must be signed manually, using the scripts/sign-file tool.
1758 comment "Do not forget to sign required modules with scripts/sign-file"
1759 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1762 prompt "Which hash algorithm should modules be signed with?"
1763 depends on MODULE_SIG
1765 This determines which sort of hashing algorithm will be used during
1766 signature generation. This algorithm _must_ be built into the kernel
1767 directly so that signature verification can take place. It is not
1768 possible to load a signed module containing the algorithm to check
1769 the signature on that module.
1771 config MODULE_SIG_SHA1
1772 bool "Sign modules with SHA-1"
1775 config MODULE_SIG_SHA224
1776 bool "Sign modules with SHA-224"
1777 select CRYPTO_SHA256
1779 config MODULE_SIG_SHA256
1780 bool "Sign modules with SHA-256"
1781 select CRYPTO_SHA256
1783 config MODULE_SIG_SHA384
1784 bool "Sign modules with SHA-384"
1785 select CRYPTO_SHA512
1787 config MODULE_SIG_SHA512
1788 bool "Sign modules with SHA-512"
1789 select CRYPTO_SHA512
1793 config MODULE_SIG_HASH
1795 depends on MODULE_SIG
1796 default "sha1" if MODULE_SIG_SHA1
1797 default "sha224" if MODULE_SIG_SHA224
1798 default "sha256" if MODULE_SIG_SHA256
1799 default "sha384" if MODULE_SIG_SHA384
1800 default "sha512" if MODULE_SIG_SHA512
1804 config INIT_ALL_POSSIBLE
1807 Back when each arch used to define their own cpu_online_mask and
1808 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1809 with all 1s, and others with all 0s. When they were centralised,
1810 it was better to provide this option than to break all the archs
1811 and have several arch maintainers pursuing me down dark alleys.
1816 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1818 Need stop_machine() primitive.
1820 source "block/Kconfig"
1822 config PREEMPT_NOTIFIERS
1829 # Can be selected by architectures with broken toolchains
1830 # that get confused by correct const<->read_only section
1832 config BROKEN_RODATA
1838 Build a simple ASN.1 grammar compiler that produces a bytecode output
1839 that can be interpreted by the ASN.1 stream decoder and used to
1840 inform it as to what tags are to be expected in a stream and what
1841 functions to call on what tags.
1843 source "kernel/Kconfig.locks"
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