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
29 config THREAD_INFO_IN_TASK
32 Select this to move thread_info off the stack into task_struct. To
33 make this work, an arch will need to remove all thread_info fields
34 except flags and fix any runtime bugs.
36 One subtle change that will be needed is to use try_get_task_stack()
37 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
46 depends on BROKEN || !SMP
49 config INIT_ENV_ARG_LIMIT
54 Maximum of each of the number of arguments and environment
55 variables passed to init from the kernel command line.
59 string "Cross-compiler tool prefix"
61 Same as running 'make CROSS_COMPILE=prefix-' but stored for
62 default make runs in this kernel build directory. You don't
63 need to set this unless you want the configured kernel build
64 directory to select the cross-compiler automatically.
67 bool "Compile also drivers which will not load"
71 Some drivers can be compiled on a different platform than they are
72 intended to be run on. Despite they cannot be loaded there (or even
73 when they load they cannot be used due to missing HW support),
74 developers still, opposing to distributors, might want to build such
75 drivers to compile-test them.
77 If you are a developer and want to build everything available, say Y
78 here. If you are a user/distributor, say N here to exclude useless
79 drivers to be distributed.
82 string "Local version - append to kernel release"
84 Append an extra string to the end of your kernel version.
85 This will show up when you type uname, for example.
86 The string you set here will be appended after the contents of
87 any files with a filename matching localversion* in your
88 object and source tree, in that order. Your total string can
89 be a maximum of 64 characters.
91 config LOCALVERSION_AUTO
92 bool "Automatically append version information to the version string"
94 depends on !COMPILE_TEST
96 This will try to automatically determine if the current tree is a
97 release tree by looking for git tags that belong to the current
100 A string of the format -gxxxxxxxx will be added to the localversion
101 if a git-based tree is found. The string generated by this will be
102 appended after any matching localversion* files, and after the value
103 set in CONFIG_LOCALVERSION.
105 (The actual string used here is the first eight characters produced
106 by running the command:
108 $ git rev-parse --verify HEAD
110 which is done within the script "scripts/setlocalversion".)
112 config HAVE_KERNEL_GZIP
115 config HAVE_KERNEL_BZIP2
118 config HAVE_KERNEL_LZMA
121 config HAVE_KERNEL_XZ
124 config HAVE_KERNEL_LZO
127 config HAVE_KERNEL_LZ4
131 prompt "Kernel compression mode"
133 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
135 The linux kernel is a kind of self-extracting executable.
136 Several compression algorithms are available, which differ
137 in efficiency, compression and decompression speed.
138 Compression speed is only relevant when building a kernel.
139 Decompression speed is relevant at each boot.
141 If you have any problems with bzip2 or lzma compressed
142 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
143 version of this functionality (bzip2 only), for 2.4, was
144 supplied by Christian Ludwig)
146 High compression options are mostly useful for users, who
147 are low on disk space (embedded systems), but for whom ram
150 If in doubt, select 'gzip'
154 depends on HAVE_KERNEL_GZIP
156 The old and tried gzip compression. It provides a good balance
157 between compression ratio and decompression speed.
161 depends on HAVE_KERNEL_BZIP2
163 Its compression ratio and speed is intermediate.
164 Decompression speed is slowest among the choices. The kernel
165 size is about 10% smaller with bzip2, in comparison to gzip.
166 Bzip2 uses a large amount of memory. For modern kernels you
167 will need at least 8MB RAM or more for booting.
171 depends on HAVE_KERNEL_LZMA
173 This compression algorithm's ratio is best. Decompression speed
174 is between gzip and bzip2. Compression is slowest.
175 The kernel size is about 33% smaller with LZMA in comparison to gzip.
179 depends on HAVE_KERNEL_XZ
181 XZ uses the LZMA2 algorithm and instruction set specific
182 BCJ filters which can improve compression ratio of executable
183 code. The size of the kernel is about 30% smaller with XZ in
184 comparison to gzip. On architectures for which there is a BCJ
185 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
186 will create a few percent smaller kernel than plain LZMA.
188 The speed is about the same as with LZMA: The decompression
189 speed of XZ is better than that of bzip2 but worse than gzip
190 and LZO. Compression is slow.
194 depends on HAVE_KERNEL_LZO
196 Its compression ratio is the poorest among the choices. The kernel
197 size is about 10% bigger than gzip; however its speed
198 (both compression and decompression) is the fastest.
202 depends on HAVE_KERNEL_LZ4
204 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
205 A preliminary version of LZ4 de/compression tool is available at
206 <https://code.google.com/p/lz4/>.
208 Its compression ratio is worse than LZO. The size of the kernel
209 is about 8% bigger than LZO. But the decompression speed is
214 config DEFAULT_HOSTNAME
215 string "Default hostname"
218 This option determines the default system hostname before userspace
219 calls sethostname(2). The kernel traditionally uses "(none)" here,
220 but you may wish to use a different default here to make a minimal
221 system more usable with less configuration.
224 bool "Support for paging of anonymous memory (swap)"
225 depends on MMU && BLOCK
228 This option allows you to choose whether you want to have support
229 for so called swap devices or swap files in your kernel that are
230 used to provide more virtual memory than the actual RAM present
231 in your computer. If unsure say Y.
236 Inter Process Communication is a suite of library functions and
237 system calls which let processes (running programs) synchronize and
238 exchange information. It is generally considered to be a good thing,
239 and some programs won't run unless you say Y here. In particular, if
240 you want to run the DOS emulator dosemu under Linux (read the
241 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
242 you'll need to say Y here.
244 You can find documentation about IPC with "info ipc" and also in
245 section 6.4 of the Linux Programmer's Guide, available from
246 <http://www.tldp.org/guides.html>.
248 config SYSVIPC_SYSCTL
255 bool "POSIX Message Queues"
258 POSIX variant of message queues is a part of IPC. In POSIX message
259 queues every message has a priority which decides about succession
260 of receiving it by a process. If you want to compile and run
261 programs written e.g. for Solaris with use of its POSIX message
262 queues (functions mq_*) say Y here.
264 POSIX message queues are visible as a filesystem called 'mqueue'
265 and can be mounted somewhere if you want to do filesystem
266 operations on message queues.
270 config POSIX_MQUEUE_SYSCTL
272 depends on POSIX_MQUEUE
276 config CROSS_MEMORY_ATTACH
277 bool "Enable process_vm_readv/writev syscalls"
281 Enabling this option adds the system calls process_vm_readv and
282 process_vm_writev which allow a process with the correct privileges
283 to directly read from or write to another process' address space.
284 See the man page for more details.
287 bool "uselib syscall"
288 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
290 This option enables the uselib syscall, a system call used in the
291 dynamic linker from libc5 and earlier. glibc does not use this
292 system call. If you intend to run programs built on libc5 or
293 earlier, you may need to enable this syscall. Current systems
294 running glibc can safely disable this.
297 bool "Auditing support"
300 Enable auditing infrastructure that can be used with another
301 kernel subsystem, such as SELinux (which requires this for
302 logging of avc messages output). System call auditing is included
303 on architectures which support it.
305 config HAVE_ARCH_AUDITSYSCALL
310 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
314 depends on AUDITSYSCALL
319 depends on AUDITSYSCALL
322 source "kernel/irq/Kconfig"
323 source "kernel/time/Kconfig"
325 menu "CPU/Task time and stats accounting"
327 config VIRT_CPU_ACCOUNTING
331 prompt "Cputime accounting"
332 default TICK_CPU_ACCOUNTING if !PPC64
333 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
335 # Kind of a stub config for the pure tick based cputime accounting
336 config TICK_CPU_ACCOUNTING
337 bool "Simple tick based cputime accounting"
338 depends on !S390 && !NO_HZ_FULL
340 This is the basic tick based cputime accounting that maintains
341 statistics about user, system and idle time spent on per jiffies
346 config VIRT_CPU_ACCOUNTING_NATIVE
347 bool "Deterministic task and CPU time accounting"
348 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
349 select VIRT_CPU_ACCOUNTING
351 Select this option to enable more accurate task and CPU time
352 accounting. This is done by reading a CPU counter on each
353 kernel entry and exit and on transitions within the kernel
354 between system, softirq and hardirq state, so there is a
355 small performance impact. In the case of s390 or IBM POWER > 5,
356 this also enables accounting of stolen time on logically-partitioned
359 config VIRT_CPU_ACCOUNTING_GEN
360 bool "Full dynticks CPU time accounting"
361 depends on HAVE_CONTEXT_TRACKING
362 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
363 select VIRT_CPU_ACCOUNTING
364 select CONTEXT_TRACKING
366 Select this option to enable task and CPU time accounting on full
367 dynticks systems. This accounting is implemented by watching every
368 kernel-user boundaries using the context tracking subsystem.
369 The accounting is thus performed at the expense of some significant
372 For now this is only useful if you are working on the full
373 dynticks subsystem development.
379 config IRQ_TIME_ACCOUNTING
380 bool "Fine granularity task level IRQ time accounting"
381 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
383 Select this option to enable fine granularity task irq time
384 accounting. This is done by reading a timestamp on each
385 transitions between softirq and hardirq state, so there can be a
386 small performance impact.
388 If in doubt, say N here.
390 config BSD_PROCESS_ACCT
391 bool "BSD Process Accounting"
394 If you say Y here, a user level program will be able to instruct the
395 kernel (via a special system call) to write process accounting
396 information to a file: whenever a process exits, information about
397 that process will be appended to the file by the kernel. The
398 information includes things such as creation time, owning user,
399 command name, memory usage, controlling terminal etc. (the complete
400 list is in the struct acct in <file:include/linux/acct.h>). It is
401 up to the user level program to do useful things with this
402 information. This is generally a good idea, so say Y.
404 config BSD_PROCESS_ACCT_V3
405 bool "BSD Process Accounting version 3 file format"
406 depends on BSD_PROCESS_ACCT
409 If you say Y here, the process accounting information is written
410 in a new file format that also logs the process IDs of each
411 process and it's parent. Note that this file format is incompatible
412 with previous v0/v1/v2 file formats, so you will need updated tools
413 for processing it. A preliminary version of these tools is available
414 at <http://www.gnu.org/software/acct/>.
417 bool "Export task/process statistics through netlink"
422 Export selected statistics for tasks/processes through the
423 generic netlink interface. Unlike BSD process accounting, the
424 statistics are available during the lifetime of tasks/processes as
425 responses to commands. Like BSD accounting, they are sent to user
430 config TASK_DELAY_ACCT
431 bool "Enable per-task delay accounting"
435 Collect information on time spent by a task waiting for system
436 resources like cpu, synchronous block I/O completion and swapping
437 in pages. Such statistics can help in setting a task's priorities
438 relative to other tasks for cpu, io, rss limits etc.
443 bool "Enable extended accounting over taskstats"
446 Collect extended task accounting data and send the data
447 to userland for processing over the taskstats interface.
451 config TASK_IO_ACCOUNTING
452 bool "Enable per-task storage I/O accounting"
453 depends on TASK_XACCT
455 Collect information on the number of bytes of storage I/O which this
460 endmenu # "CPU/Task time and stats accounting"
466 Make sure that CPUs running critical tasks are not disturbed by
467 any source of "noise" such as unbound workqueues, timers, kthreads...
468 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
469 the "isolcpus=" boot parameter.
473 source "kernel/rcu/Kconfig"
480 tristate "Kernel .config support"
483 This option enables the complete Linux kernel ".config" file
484 contents to be saved in the kernel. It provides documentation
485 of which kernel options are used in a running kernel or in an
486 on-disk kernel. This information can be extracted from the kernel
487 image file with the script scripts/extract-ikconfig and used as
488 input to rebuild the current kernel or to build another kernel.
489 It can also be extracted from a running kernel by reading
490 /proc/config.gz if enabled (below).
493 bool "Enable access to .config through /proc/config.gz"
494 depends on IKCONFIG && PROC_FS
496 This option enables access to the kernel configuration file
497 through /proc/config.gz.
500 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
505 Select the minimal kernel log buffer size as a power of 2.
506 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
507 parameter, see below. Any higher size also might be forced
508 by "log_buf_len" boot parameter.
518 config LOG_CPU_MAX_BUF_SHIFT
519 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
522 default 12 if !BASE_SMALL
523 default 0 if BASE_SMALL
526 This option allows to increase the default ring buffer size
527 according to the number of CPUs. The value defines the contribution
528 of each CPU as a power of 2. The used space is typically only few
529 lines however it might be much more when problems are reported,
532 The increased size means that a new buffer has to be allocated and
533 the original static one is unused. It makes sense only on systems
534 with more CPUs. Therefore this value is used only when the sum of
535 contributions is greater than the half of the default kernel ring
536 buffer as defined by LOG_BUF_SHIFT. The default values are set
537 so that more than 64 CPUs are needed to trigger the allocation.
539 Also this option is ignored when "log_buf_len" kernel parameter is
540 used as it forces an exact (power of two) size of the ring buffer.
542 The number of possible CPUs is used for this computation ignoring
543 hotplugging making the computation optimal for the worst case
544 scenario while allowing a simple algorithm to be used from bootup.
546 Examples shift values and their meaning:
547 17 => 128 KB for each CPU
548 16 => 64 KB for each CPU
549 15 => 32 KB for each CPU
550 14 => 16 KB for each CPU
551 13 => 8 KB for each CPU
552 12 => 4 KB for each CPU
554 config PRINTK_SAFE_LOG_BUF_SHIFT
555 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
560 Select the size of an alternate printk per-CPU buffer where messages
561 printed from usafe contexts are temporary stored. One example would
562 be NMI messages, another one - printk recursion. The messages are
563 copied to the main log buffer in a safe context to avoid a deadlock.
564 The value defines the size as a power of 2.
566 Those messages are rare and limited. The largest one is when
567 a backtrace is printed. It usually fits into 4KB. Select
568 8KB if you want to be on the safe side.
571 17 => 128 KB for each CPU
572 16 => 64 KB for each CPU
573 15 => 32 KB for each CPU
574 14 => 16 KB for each CPU
575 13 => 8 KB for each CPU
576 12 => 4 KB for each CPU
579 # Architectures with an unreliable sched_clock() should select this:
581 config HAVE_UNSTABLE_SCHED_CLOCK
584 config GENERIC_SCHED_CLOCK
588 # For architectures that want to enable the support for NUMA-affine scheduler
591 config ARCH_SUPPORTS_NUMA_BALANCING
595 # For architectures that prefer to flush all TLBs after a number of pages
596 # are unmapped instead of sending one IPI per page to flush. The architecture
597 # must provide guarantees on what happens if a clean TLB cache entry is
598 # written after the unmap. Details are in mm/rmap.c near the check for
599 # should_defer_flush. The architecture should also consider if the full flush
600 # and the refill costs are offset by the savings of sending fewer IPIs.
601 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
605 # For architectures that know their GCC __int128 support is sound
607 config ARCH_SUPPORTS_INT128
610 # For architectures that (ab)use NUMA to represent different memory regions
611 # all cpu-local but of different latencies, such as SuperH.
613 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
616 config NUMA_BALANCING
617 bool "Memory placement aware NUMA scheduler"
618 depends on ARCH_SUPPORTS_NUMA_BALANCING
619 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
620 depends on SMP && NUMA && MIGRATION
622 This option adds support for automatic NUMA aware memory/task placement.
623 The mechanism is quite primitive and is based on migrating memory when
624 it has references to the node the task is running on.
626 This system will be inactive on UMA systems.
628 config NUMA_BALANCING_DEFAULT_ENABLED
629 bool "Automatically enable NUMA aware memory/task placement"
631 depends on NUMA_BALANCING
633 If set, automatic NUMA balancing will be enabled if running on a NUMA
637 bool "Control Group support"
640 This option adds support for grouping sets of processes together, for
641 use with process control subsystems such as Cpusets, CFS, memory
642 controls or device isolation.
644 - Documentation/scheduler/sched-design-CFS.txt (CFS)
645 - Documentation/cgroup-v1/ (features for grouping, isolation
646 and resource control)
656 bool "Memory controller"
660 Provides control over the memory footprint of tasks in a cgroup.
663 bool "Swap controller"
664 depends on MEMCG && SWAP
666 Provides control over the swap space consumed by tasks in a cgroup.
668 config MEMCG_SWAP_ENABLED
669 bool "Swap controller enabled by default"
670 depends on MEMCG_SWAP
673 Memory Resource Controller Swap Extension comes with its price in
674 a bigger memory consumption. General purpose distribution kernels
675 which want to enable the feature but keep it disabled by default
676 and let the user enable it by swapaccount=1 boot command line
677 parameter should have this option unselected.
678 For those who want to have the feature enabled by default should
679 select this option (if, for some reason, they need to disable it
680 then swapaccount=0 does the trick).
687 Generic block IO controller cgroup interface. This is the common
688 cgroup interface which should be used by various IO controlling
691 Currently, CFQ IO scheduler uses it to recognize task groups and
692 control disk bandwidth allocation (proportional time slice allocation)
693 to such task groups. It is also used by bio throttling logic in
694 block layer to implement upper limit in IO rates on a device.
696 This option only enables generic Block IO controller infrastructure.
697 One needs to also enable actual IO controlling logic/policy. For
698 enabling proportional weight division of disk bandwidth in CFQ, set
699 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
700 CONFIG_BLK_DEV_THROTTLING=y.
702 See Documentation/cgroup-v1/blkio-controller.txt for more information.
704 config DEBUG_BLK_CGROUP
705 bool "IO controller debugging"
706 depends on BLK_CGROUP
709 Enable some debugging help. Currently it exports additional stat
710 files in a cgroup which can be useful for debugging.
712 config CGROUP_WRITEBACK
714 depends on MEMCG && BLK_CGROUP
717 menuconfig CGROUP_SCHED
718 bool "CPU controller"
721 This feature lets CPU scheduler recognize task groups and control CPU
722 bandwidth allocation to such task groups. It uses cgroups to group
726 config FAIR_GROUP_SCHED
727 bool "Group scheduling for SCHED_OTHER"
728 depends on CGROUP_SCHED
732 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
733 depends on FAIR_GROUP_SCHED
736 This option allows users to define CPU bandwidth rates (limits) for
737 tasks running within the fair group scheduler. Groups with no limit
738 set are considered to be unconstrained and will run with no
740 See tip/Documentation/scheduler/sched-bwc.txt for more information.
742 config RT_GROUP_SCHED
743 bool "Group scheduling for SCHED_RR/FIFO"
744 depends on CGROUP_SCHED
747 This feature lets you explicitly allocate real CPU bandwidth
748 to task groups. If enabled, it will also make it impossible to
749 schedule realtime tasks for non-root users until you allocate
750 realtime bandwidth for them.
751 See Documentation/scheduler/sched-rt-group.txt for more information.
756 bool "PIDs controller"
758 Provides enforcement of process number limits in the scope of a
759 cgroup. Any attempt to fork more processes than is allowed in the
760 cgroup will fail. PIDs are fundamentally a global resource because it
761 is fairly trivial to reach PID exhaustion before you reach even a
762 conservative kmemcg limit. As a result, it is possible to grind a
763 system to halt without being limited by other cgroup policies. The
764 PIDs controller is designed to stop this from happening.
766 It should be noted that organisational operations (such as attaching
767 to a cgroup hierarchy will *not* be blocked by the PIDs controller),
768 since the PIDs limit only affects a process's ability to fork, not to
772 bool "RDMA controller"
774 Provides enforcement of RDMA resources defined by IB stack.
775 It is fairly easy for consumers to exhaust RDMA resources, which
776 can result into resource unavailability to other consumers.
777 RDMA controller is designed to stop this from happening.
778 Attaching processes with active RDMA resources to the cgroup
779 hierarchy is allowed even if can cross the hierarchy's limit.
781 config CGROUP_FREEZER
782 bool "Freezer controller"
784 Provides a way to freeze and unfreeze all tasks in a
787 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
788 controller includes important in-kernel memory consumers per default.
790 If you're using cgroup2, say N.
792 config CGROUP_HUGETLB
793 bool "HugeTLB controller"
794 depends on HUGETLB_PAGE
798 Provides a cgroup controller for HugeTLB pages.
799 When you enable this, you can put a per cgroup limit on HugeTLB usage.
800 The limit is enforced during page fault. Since HugeTLB doesn't
801 support page reclaim, enforcing the limit at page fault time implies
802 that, the application will get SIGBUS signal if it tries to access
803 HugeTLB pages beyond its limit. This requires the application to know
804 beforehand how much HugeTLB pages it would require for its use. The
805 control group is tracked in the third page lru pointer. This means
806 that we cannot use the controller with huge page less than 3 pages.
809 bool "Cpuset controller"
812 This option will let you create and manage CPUSETs which
813 allow dynamically partitioning a system into sets of CPUs and
814 Memory Nodes and assigning tasks to run only within those sets.
815 This is primarily useful on large SMP or NUMA systems.
819 config PROC_PID_CPUSET
820 bool "Include legacy /proc/<pid>/cpuset file"
825 bool "Device controller"
827 Provides a cgroup controller implementing whitelists for
828 devices which a process in the cgroup can mknod or open.
830 config CGROUP_CPUACCT
831 bool "Simple CPU accounting controller"
833 Provides a simple controller for monitoring the
834 total CPU consumed by the tasks in a cgroup.
837 bool "Perf controller"
838 depends on PERF_EVENTS
840 This option extends the perf per-cpu mode to restrict monitoring
841 to threads which belong to the cgroup specified and run on the
847 bool "Support for eBPF programs attached to cgroups"
848 depends on BPF_SYSCALL
849 select SOCK_CGROUP_DATA
851 Allow attaching eBPF programs to a cgroup using the bpf(2)
852 syscall command BPF_PROG_ATTACH.
854 In which context these programs are accessed depends on the type
855 of attachment. For instance, programs that are attached using
856 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
860 bool "Debug controller"
862 depends on DEBUG_KERNEL
864 This option enables a simple controller that exports
865 debugging information about the cgroups framework. This
866 controller is for control cgroup debugging only. Its
867 interfaces are not stable.
871 config SOCK_CGROUP_DATA
877 menuconfig NAMESPACES
878 bool "Namespaces support" if EXPERT
882 Provides the way to make tasks work with different objects using
883 the same id. For example same IPC id may refer to different objects
884 or same user id or pid may refer to different tasks when used in
885 different namespaces.
893 In this namespace tasks see different info provided with the
898 depends on (SYSVIPC || POSIX_MQUEUE)
901 In this namespace tasks work with IPC ids which correspond to
902 different IPC objects in different namespaces.
905 bool "User namespace"
908 This allows containers, i.e. vservers, to use user namespaces
909 to provide different user info for different servers.
911 When user namespaces are enabled in the kernel it is
912 recommended that the MEMCG option also be enabled and that
913 user-space use the memory control groups to limit the amount
914 of memory a memory unprivileged users can use.
919 bool "PID Namespaces"
922 Support process id namespaces. This allows having multiple
923 processes with the same pid as long as they are in different
924 pid namespaces. This is a building block of containers.
927 bool "Network namespace"
931 Allow user space to create what appear to be multiple instances
932 of the network stack.
936 config SCHED_AUTOGROUP
937 bool "Automatic process group scheduling"
940 select FAIR_GROUP_SCHED
942 This option optimizes the scheduler for common desktop workloads by
943 automatically creating and populating task groups. This separation
944 of workloads isolates aggressive CPU burners (like build jobs) from
945 desktop applications. Task group autogeneration is currently based
948 config SYSFS_DEPRECATED
949 bool "Enable deprecated sysfs features to support old userspace tools"
953 This option adds code that switches the layout of the "block" class
954 devices, to not show up in /sys/class/block/, but only in
957 This switch is only active when the sysfs.deprecated=1 boot option is
958 passed or the SYSFS_DEPRECATED_V2 option is set.
960 This option allows new kernels to run on old distributions and tools,
961 which might get confused by /sys/class/block/. Since 2007/2008 all
962 major distributions and tools handle this just fine.
964 Recent distributions and userspace tools after 2009/2010 depend on
965 the existence of /sys/class/block/, and will not work with this
968 Only if you are using a new kernel on an old distribution, you might
971 config SYSFS_DEPRECATED_V2
972 bool "Enable deprecated sysfs features by default"
975 depends on SYSFS_DEPRECATED
977 Enable deprecated sysfs by default.
979 See the CONFIG_SYSFS_DEPRECATED option for more details about this
982 Only if you are using a new kernel on an old distribution, you might
983 need to say Y here. Even then, odds are you would not need it
984 enabled, you can always pass the boot option if absolutely necessary.
987 bool "Kernel->user space relay support (formerly relayfs)"
990 This option enables support for relay interface support in
991 certain file systems (such as debugfs).
992 It is designed to provide an efficient mechanism for tools and
993 facilities to relay large amounts of data from kernel space to
998 config BLK_DEV_INITRD
999 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1000 depends on BROKEN || !FRV
1002 The initial RAM filesystem is a ramfs which is loaded by the
1003 boot loader (loadlin or lilo) and that is mounted as root
1004 before the normal boot procedure. It is typically used to
1005 load modules needed to mount the "real" root file system,
1006 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1008 If RAM disk support (BLK_DEV_RAM) is also included, this
1009 also enables initial RAM disk (initrd) support and adds
1010 15 Kbytes (more on some other architectures) to the kernel size.
1016 source "usr/Kconfig"
1021 prompt "Compiler optimization level"
1022 default CC_OPTIMIZE_FOR_PERFORMANCE
1024 config CC_OPTIMIZE_FOR_PERFORMANCE
1025 bool "Optimize for performance"
1027 This is the default optimization level for the kernel, building
1028 with the "-O2" compiler flag for best performance and most
1029 helpful compile-time warnings.
1031 config CC_OPTIMIZE_FOR_SIZE
1032 bool "Optimize for size"
1034 Enabling this option will pass "-Os" instead of "-O2" to
1035 your compiler resulting in a smaller kernel.
1050 config SYSCTL_EXCEPTION_TRACE
1053 Enable support for /proc/sys/debug/exception-trace.
1055 config SYSCTL_ARCH_UNALIGN_NO_WARN
1058 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1059 Allows arch to define/use @no_unaligned_warning to possibly warn
1060 about unaligned access emulation going on under the hood.
1062 config SYSCTL_ARCH_UNALIGN_ALLOW
1065 Enable support for /proc/sys/kernel/unaligned-trap
1066 Allows arches to define/use @unaligned_enabled to runtime toggle
1067 the unaligned access emulation.
1068 see arch/parisc/kernel/unaligned.c for reference
1070 config HAVE_PCSPKR_PLATFORM
1073 # interpreter that classic socket filters depend on
1078 bool "Configure standard kernel features (expert users)"
1079 # Unhide debug options, to make the on-by-default options visible
1082 This option allows certain base kernel options and settings
1083 to be disabled or tweaked. This is for specialized
1084 environments which can tolerate a "non-standard" kernel.
1085 Only use this if you really know what you are doing.
1088 bool "Enable 16-bit UID system calls" if EXPERT
1089 depends on HAVE_UID16 && MULTIUSER
1092 This enables the legacy 16-bit UID syscall wrappers.
1095 bool "Multiple users, groups and capabilities support" if EXPERT
1098 This option enables support for non-root users, groups and
1101 If you say N here, all processes will run with UID 0, GID 0, and all
1102 possible capabilities. Saying N here also compiles out support for
1103 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1106 If unsure, say Y here.
1108 config SGETMASK_SYSCALL
1109 bool "sgetmask/ssetmask syscalls support" if EXPERT
1110 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1112 sys_sgetmask and sys_ssetmask are obsolete system calls
1113 no longer supported in libc but still enabled by default in some
1116 If unsure, leave the default option here.
1118 config SYSFS_SYSCALL
1119 bool "Sysfs syscall support" if EXPERT
1122 sys_sysfs is an obsolete system call no longer supported in libc.
1123 Note that disabling this option is more secure but might break
1124 compatibility with some systems.
1126 If unsure say Y here.
1128 config SYSCTL_SYSCALL
1129 bool "Sysctl syscall support" if EXPERT
1130 depends on PROC_SYSCTL
1134 sys_sysctl uses binary paths that have been found challenging
1135 to properly maintain and use. The interface in /proc/sys
1136 using paths with ascii names is now the primary path to this
1139 Almost nothing using the binary sysctl interface so if you are
1140 trying to save some space it is probably safe to disable this,
1141 making your kernel marginally smaller.
1143 If unsure say N here.
1146 bool "open by fhandle syscalls" if EXPERT
1150 If you say Y here, a user level program will be able to map
1151 file names to handle and then later use the handle for
1152 different file system operations. This is useful in implementing
1153 userspace file servers, which now track files using handles instead
1154 of names. The handle would remain the same even if file names
1155 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1159 bool "Posix Clocks & timers" if EXPERT
1162 This includes native support for POSIX timers to the kernel.
1163 Some embedded systems have no use for them and therefore they
1164 can be configured out to reduce the size of the kernel image.
1166 When this option is disabled, the following syscalls won't be
1167 available: timer_create, timer_gettime: timer_getoverrun,
1168 timer_settime, timer_delete, clock_adjtime, getitimer,
1169 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1170 clock_getres and clock_nanosleep syscalls will be limited to
1171 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1177 bool "Enable support for printk" if EXPERT
1180 This option enables normal printk support. Removing it
1181 eliminates most of the message strings from the kernel image
1182 and makes the kernel more or less silent. As this makes it
1183 very difficult to diagnose system problems, saying N here is
1184 strongly discouraged.
1192 bool "BUG() support" if EXPERT
1195 Disabling this option eliminates support for BUG and WARN, reducing
1196 the size of your kernel image and potentially quietly ignoring
1197 numerous fatal conditions. You should only consider disabling this
1198 option for embedded systems with no facilities for reporting errors.
1204 bool "Enable ELF core dumps" if EXPERT
1206 Enable support for generating core dumps. Disabling saves about 4k.
1209 config PCSPKR_PLATFORM
1210 bool "Enable PC-Speaker support" if EXPERT
1211 depends on HAVE_PCSPKR_PLATFORM
1215 This option allows to disable the internal PC-Speaker
1216 support, saving some memory.
1220 bool "Enable full-sized data structures for core" if EXPERT
1222 Disabling this option reduces the size of miscellaneous core
1223 kernel data structures. This saves memory on small machines,
1224 but may reduce performance.
1227 bool "Enable futex support" if EXPERT
1231 Disabling this option will cause the kernel to be built without
1232 support for "fast userspace mutexes". The resulting kernel may not
1233 run glibc-based applications correctly.
1237 depends on FUTEX && RT_MUTEXES
1240 config HAVE_FUTEX_CMPXCHG
1244 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1245 is implemented and always working. This removes a couple of runtime
1249 bool "Enable eventpoll support" if EXPERT
1253 Disabling this option will cause the kernel to be built without
1254 support for epoll family of system calls.
1257 bool "Enable signalfd() system call" if EXPERT
1261 Enable the signalfd() system call that allows to receive signals
1262 on a file descriptor.
1267 bool "Enable timerfd() system call" if EXPERT
1271 Enable the timerfd() system call that allows to receive timer
1272 events on a file descriptor.
1277 bool "Enable eventfd() system call" if EXPERT
1281 Enable the eventfd() system call that allows to receive both
1282 kernel notification (ie. KAIO) or userspace notifications.
1287 bool "Use full shmem filesystem" if EXPERT
1291 The shmem is an internal filesystem used to manage shared memory.
1292 It is backed by swap and manages resource limits. It is also exported
1293 to userspace as tmpfs if TMPFS is enabled. Disabling this
1294 option replaces shmem and tmpfs with the much simpler ramfs code,
1295 which may be appropriate on small systems without swap.
1298 bool "Enable AIO support" if EXPERT
1301 This option enables POSIX asynchronous I/O which may by used
1302 by some high performance threaded applications. Disabling
1303 this option saves about 7k.
1305 config ADVISE_SYSCALLS
1306 bool "Enable madvise/fadvise syscalls" if EXPERT
1309 This option enables the madvise and fadvise syscalls, used by
1310 applications to advise the kernel about their future memory or file
1311 usage, improving performance. If building an embedded system where no
1312 applications use these syscalls, you can disable this option to save
1316 bool "Enable membarrier() system call" if EXPERT
1319 Enable the membarrier() system call that allows issuing memory
1320 barriers across all running threads, which can be used to distribute
1321 the cost of user-space memory barriers asymmetrically by transforming
1322 pairs of memory barriers into pairs consisting of membarrier() and a
1327 config CHECKPOINT_RESTORE
1328 bool "Checkpoint/restore support" if EXPERT
1329 select PROC_CHILDREN
1332 Enables additional kernel features in a sake of checkpoint/restore.
1333 In particular it adds auxiliary prctl codes to setup process text,
1334 data and heap segment sizes, and a few additional /proc filesystem
1337 If unsure, say N here.
1340 bool "Load all symbols for debugging/ksymoops" if EXPERT
1343 Say Y here to let the kernel print out symbolic crash information and
1344 symbolic stack backtraces. This increases the size of the kernel
1345 somewhat, as all symbols have to be loaded into the kernel image.
1348 bool "Include all symbols in kallsyms"
1349 depends on DEBUG_KERNEL && KALLSYMS
1351 Normally kallsyms only contains the symbols of functions for nicer
1352 OOPS messages and backtraces (i.e., symbols from the text and inittext
1353 sections). This is sufficient for most cases. And only in very rare
1354 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1355 names of variables from the data sections, etc).
1357 This option makes sure that all symbols are loaded into the kernel
1358 image (i.e., symbols from all sections) in cost of increased kernel
1359 size (depending on the kernel configuration, it may be 300KiB or
1360 something like this).
1362 Say N unless you really need all symbols.
1364 config KALLSYMS_ABSOLUTE_PERCPU
1367 default X86_64 && SMP
1369 config KALLSYMS_BASE_RELATIVE
1372 default !IA64 && !(TILE && 64BIT)
1374 Instead of emitting them as absolute values in the native word size,
1375 emit the symbol references in the kallsyms table as 32-bit entries,
1376 each containing a relative value in the range [base, base + U32_MAX]
1377 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
1378 an absolute value in the range [0, S32_MAX] or a relative value in the
1379 range [base, base + S32_MAX], where base is the lowest relative symbol
1380 address encountered in the image.
1382 On 64-bit builds, this reduces the size of the address table by 50%,
1383 but more importantly, it results in entries whose values are build
1384 time constants, and no relocation pass is required at runtime to fix
1385 up the entries based on the runtime load address of the kernel.
1387 # end of the "standard kernel features (expert users)" menu
1389 # syscall, maps, verifier
1391 bool "Enable bpf() system call"
1396 Enable the bpf() system call that allows to manipulate eBPF
1397 programs and maps via file descriptors.
1400 bool "Enable userfaultfd() system call"
1404 Enable the userfaultfd() system call that allows to intercept and
1405 handle page faults in userland.
1408 bool "Embedded system"
1409 option allnoconfig_y
1412 This option should be enabled if compiling the kernel for
1413 an embedded system so certain expert options are available
1416 config HAVE_PERF_EVENTS
1419 See tools/perf/design.txt for details.
1421 config PERF_USE_VMALLOC
1424 See tools/perf/design.txt for details
1427 bool "PC/104 support"
1429 Expose PC/104 form factor device drivers and options available for
1430 selection and configuration. Enable this option if your target
1431 machine has a PC/104 bus.
1433 menu "Kernel Performance Events And Counters"
1436 bool "Kernel performance events and counters"
1437 default y if PROFILING
1438 depends on HAVE_PERF_EVENTS
1443 Enable kernel support for various performance events provided
1444 by software and hardware.
1446 Software events are supported either built-in or via the
1447 use of generic tracepoints.
1449 Most modern CPUs support performance events via performance
1450 counter registers. These registers count the number of certain
1451 types of hw events: such as instructions executed, cachemisses
1452 suffered, or branches mis-predicted - without slowing down the
1453 kernel or applications. These registers can also trigger interrupts
1454 when a threshold number of events have passed - and can thus be
1455 used to profile the code that runs on that CPU.
1457 The Linux Performance Event subsystem provides an abstraction of
1458 these software and hardware event capabilities, available via a
1459 system call and used by the "perf" utility in tools/perf/. It
1460 provides per task and per CPU counters, and it provides event
1461 capabilities on top of those.
1465 config DEBUG_PERF_USE_VMALLOC
1467 bool "Debug: use vmalloc to back perf mmap() buffers"
1468 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1469 select PERF_USE_VMALLOC
1471 Use vmalloc memory to back perf mmap() buffers.
1473 Mostly useful for debugging the vmalloc code on platforms
1474 that don't require it.
1480 config VM_EVENT_COUNTERS
1482 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1484 VM event counters are needed for event counts to be shown.
1485 This option allows the disabling of the VM event counters
1486 on EXPERT systems. /proc/vmstat will only show page counts
1487 if VM event counters are disabled.
1491 bool "Enable SLUB debugging support" if EXPERT
1492 depends on SLUB && SYSFS
1494 SLUB has extensive debug support features. Disabling these can
1495 result in significant savings in code size. This also disables
1496 SLUB sysfs support. /sys/slab will not exist and there will be
1497 no support for cache validation etc.
1499 config SLUB_MEMCG_SYSFS_ON
1501 bool "Enable memcg SLUB sysfs support by default" if EXPERT
1502 depends on SLUB && SYSFS && MEMCG
1504 SLUB creates a directory under /sys/kernel/slab for each
1505 allocation cache to host info and debug files. If memory
1506 cgroup is enabled, each cache can have per memory cgroup
1507 caches. SLUB can create the same sysfs directories for these
1508 caches under /sys/kernel/slab/CACHE/cgroup but it can lead
1509 to a very high number of debug files being created. This is
1510 controlled by slub_memcg_sysfs boot parameter and this
1511 config option determines the parameter's default value.
1514 bool "Disable heap randomization"
1517 Randomizing heap placement makes heap exploits harder, but it
1518 also breaks ancient binaries (including anything libc5 based).
1519 This option changes the bootup default to heap randomization
1520 disabled, and can be overridden at runtime by setting
1521 /proc/sys/kernel/randomize_va_space to 2.
1523 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1526 prompt "Choose SLAB allocator"
1529 This option allows to select a slab allocator.
1533 select HAVE_HARDENED_USERCOPY_ALLOCATOR
1535 The regular slab allocator that is established and known to work
1536 well in all environments. It organizes cache hot objects in
1537 per cpu and per node queues.
1540 bool "SLUB (Unqueued Allocator)"
1541 select HAVE_HARDENED_USERCOPY_ALLOCATOR
1543 SLUB is a slab allocator that minimizes cache line usage
1544 instead of managing queues of cached objects (SLAB approach).
1545 Per cpu caching is realized using slabs of objects instead
1546 of queues of objects. SLUB can use memory efficiently
1547 and has enhanced diagnostics. SLUB is the default choice for
1552 bool "SLOB (Simple Allocator)"
1554 SLOB replaces the stock allocator with a drastically simpler
1555 allocator. SLOB is generally more space efficient but
1556 does not perform as well on large systems.
1560 config SLAB_MERGE_DEFAULT
1561 bool "Allow slab caches to be merged"
1564 For reduced kernel memory fragmentation, slab caches can be
1565 merged when they share the same size and other characteristics.
1566 This carries a risk of kernel heap overflows being able to
1567 overwrite objects from merged caches (and more easily control
1568 cache layout), which makes such heap attacks easier to exploit
1569 by attackers. By keeping caches unmerged, these kinds of exploits
1570 can usually only damage objects in the same cache. To disable
1571 merging at runtime, "slab_nomerge" can be passed on the kernel
1574 config SLAB_FREELIST_RANDOM
1576 depends on SLAB || SLUB
1577 bool "SLAB freelist randomization"
1579 Randomizes the freelist order used on creating new pages. This
1580 security feature reduces the predictability of the kernel slab
1581 allocator against heap overflows.
1583 config SLAB_FREELIST_HARDENED
1584 bool "Harden slab freelist metadata"
1587 Many kernel heap attacks try to target slab cache metadata and
1588 other infrastructure. This options makes minor performance
1589 sacrifies to harden the kernel slab allocator against common
1590 freelist exploit methods.
1592 config SLUB_CPU_PARTIAL
1594 depends on SLUB && SMP
1595 bool "SLUB per cpu partial cache"
1597 Per cpu partial caches accellerate objects allocation and freeing
1598 that is local to a processor at the price of more indeterminism
1599 in the latency of the free. On overflow these caches will be cleared
1600 which requires the taking of locks that may cause latency spikes.
1601 Typically one would choose no for a realtime system.
1603 config MMAP_ALLOW_UNINITIALIZED
1604 bool "Allow mmapped anonymous memory to be uninitialized"
1605 depends on EXPERT && !MMU
1608 Normally, and according to the Linux spec, anonymous memory obtained
1609 from mmap() has it's contents cleared before it is passed to
1610 userspace. Enabling this config option allows you to request that
1611 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1612 providing a huge performance boost. If this option is not enabled,
1613 then the flag will be ignored.
1615 This is taken advantage of by uClibc's malloc(), and also by
1616 ELF-FDPIC binfmt's brk and stack allocator.
1618 Because of the obvious security issues, this option should only be
1619 enabled on embedded devices where you control what is run in
1620 userspace. Since that isn't generally a problem on no-MMU systems,
1621 it is normally safe to say Y here.
1623 See Documentation/nommu-mmap.txt for more information.
1625 config SYSTEM_DATA_VERIFICATION
1627 select SYSTEM_TRUSTED_KEYRING
1631 select ASYMMETRIC_KEY_TYPE
1632 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1635 select X509_CERTIFICATE_PARSER
1636 select PKCS7_MESSAGE_PARSER
1638 Provide PKCS#7 message verification using the contents of the system
1639 trusted keyring to provide public keys. This then can be used for
1640 module verification, kexec image verification and firmware blob
1644 bool "Profiling support"
1646 Say Y here to enable the extended profiling support mechanisms used
1647 by profilers such as OProfile.
1650 # Place an empty function call at each tracepoint site. Can be
1651 # dynamically changed for a probe function.
1656 source "arch/Kconfig"
1658 endmenu # General setup
1660 config HAVE_GENERIC_DMA_COHERENT
1669 default 0 if BASE_FULL
1670 default 1 if !BASE_FULL
1673 bool "Enable loadable module support"
1676 Kernel modules are small pieces of compiled code which can
1677 be inserted in the running kernel, rather than being
1678 permanently built into the kernel. You use the "modprobe"
1679 tool to add (and sometimes remove) them. If you say Y here,
1680 many parts of the kernel can be built as modules (by
1681 answering M instead of Y where indicated): this is most
1682 useful for infrequently used options which are not required
1683 for booting. For more information, see the man pages for
1684 modprobe, lsmod, modinfo, insmod and rmmod.
1686 If you say Y here, you will need to run "make
1687 modules_install" to put the modules under /lib/modules/
1688 where modprobe can find them (you may need to be root to do
1695 config MODULE_FORCE_LOAD
1696 bool "Forced module loading"
1699 Allow loading of modules without version information (ie. modprobe
1700 --force). Forced module loading sets the 'F' (forced) taint flag and
1701 is usually a really bad idea.
1703 config MODULE_UNLOAD
1704 bool "Module unloading"
1706 Without this option you will not be able to unload any
1707 modules (note that some modules may not be unloadable
1708 anyway), which makes your kernel smaller, faster
1709 and simpler. If unsure, say Y.
1711 config MODULE_FORCE_UNLOAD
1712 bool "Forced module unloading"
1713 depends on MODULE_UNLOAD
1715 This option allows you to force a module to unload, even if the
1716 kernel believes it is unsafe: the kernel will remove the module
1717 without waiting for anyone to stop using it (using the -f option to
1718 rmmod). This is mainly for kernel developers and desperate users.
1722 bool "Module versioning support"
1724 Usually, you have to use modules compiled with your kernel.
1725 Saying Y here makes it sometimes possible to use modules
1726 compiled for different kernels, by adding enough information
1727 to the modules to (hopefully) spot any changes which would
1728 make them incompatible with the kernel you are running. If
1731 config MODULE_REL_CRCS
1733 depends on MODVERSIONS
1735 config MODULE_SRCVERSION_ALL
1736 bool "Source checksum for all modules"
1738 Modules which contain a MODULE_VERSION get an extra "srcversion"
1739 field inserted into their modinfo section, which contains a
1740 sum of the source files which made it. This helps maintainers
1741 see exactly which source was used to build a module (since
1742 others sometimes change the module source without updating
1743 the version). With this option, such a "srcversion" field
1744 will be created for all modules. If unsure, say N.
1747 bool "Module signature verification"
1749 select SYSTEM_DATA_VERIFICATION
1751 Check modules for valid signatures upon load: the signature
1752 is simply appended to the module. For more information see
1753 <file:Documentation/admin-guide/module-signing.rst>.
1755 Note that this option adds the OpenSSL development packages as a
1756 kernel build dependency so that the signing tool can use its crypto
1759 !!!WARNING!!! If you enable this option, you MUST make sure that the
1760 module DOES NOT get stripped after being signed. This includes the
1761 debuginfo strip done by some packagers (such as rpmbuild) and
1762 inclusion into an initramfs that wants the module size reduced.
1764 config MODULE_SIG_FORCE
1765 bool "Require modules to be validly signed"
1766 depends on MODULE_SIG
1768 Reject unsigned modules or signed modules for which we don't have a
1769 key. Without this, such modules will simply taint the kernel.
1771 config MODULE_SIG_ALL
1772 bool "Automatically sign all modules"
1774 depends on MODULE_SIG
1776 Sign all modules during make modules_install. Without this option,
1777 modules must be signed manually, using the scripts/sign-file tool.
1779 comment "Do not forget to sign required modules with scripts/sign-file"
1780 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1783 prompt "Which hash algorithm should modules be signed with?"
1784 depends on MODULE_SIG
1786 This determines which sort of hashing algorithm will be used during
1787 signature generation. This algorithm _must_ be built into the kernel
1788 directly so that signature verification can take place. It is not
1789 possible to load a signed module containing the algorithm to check
1790 the signature on that module.
1792 config MODULE_SIG_SHA1
1793 bool "Sign modules with SHA-1"
1796 config MODULE_SIG_SHA224
1797 bool "Sign modules with SHA-224"
1798 select CRYPTO_SHA256
1800 config MODULE_SIG_SHA256
1801 bool "Sign modules with SHA-256"
1802 select CRYPTO_SHA256
1804 config MODULE_SIG_SHA384
1805 bool "Sign modules with SHA-384"
1806 select CRYPTO_SHA512
1808 config MODULE_SIG_SHA512
1809 bool "Sign modules with SHA-512"
1810 select CRYPTO_SHA512
1814 config MODULE_SIG_HASH
1816 depends on MODULE_SIG
1817 default "sha1" if MODULE_SIG_SHA1
1818 default "sha224" if MODULE_SIG_SHA224
1819 default "sha256" if MODULE_SIG_SHA256
1820 default "sha384" if MODULE_SIG_SHA384
1821 default "sha512" if MODULE_SIG_SHA512
1823 config MODULE_COMPRESS
1824 bool "Compress modules on installation"
1828 Compresses kernel modules when 'make modules_install' is run; gzip or
1829 xz depending on "Compression algorithm" below.
1831 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
1833 Out-of-tree kernel modules installed using Kbuild will also be
1834 compressed upon installation.
1836 Note: for modules inside an initrd or initramfs, it's more efficient
1837 to compress the whole initrd or initramfs instead.
1839 Note: This is fully compatible with signed modules.
1844 prompt "Compression algorithm"
1845 depends on MODULE_COMPRESS
1846 default MODULE_COMPRESS_GZIP
1848 This determines which sort of compression will be used during
1849 'make modules_install'.
1851 GZIP (default) and XZ are supported.
1853 config MODULE_COMPRESS_GZIP
1856 config MODULE_COMPRESS_XZ
1861 config TRIM_UNUSED_KSYMS
1862 bool "Trim unused exported kernel symbols"
1863 depends on MODULES && !UNUSED_SYMBOLS
1865 The kernel and some modules make many symbols available for
1866 other modules to use via EXPORT_SYMBOL() and variants. Depending
1867 on the set of modules being selected in your kernel configuration,
1868 many of those exported symbols might never be used.
1870 This option allows for unused exported symbols to be dropped from
1871 the build. In turn, this provides the compiler more opportunities
1872 (especially when using LTO) for optimizing the code and reducing
1873 binary size. This might have some security advantages as well.
1875 If unsure, or if you need to build out-of-tree modules, say N.
1879 config MODULES_TREE_LOOKUP
1881 depends on PERF_EVENTS || TRACING
1883 config INIT_ALL_POSSIBLE
1886 Back when each arch used to define their own cpu_online_mask and
1887 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1888 with all 1s, and others with all 0s. When they were centralised,
1889 it was better to provide this option than to break all the archs
1890 and have several arch maintainers pursuing me down dark alleys.
1892 source "block/Kconfig"
1894 config PREEMPT_NOTIFIERS
1904 Build a simple ASN.1 grammar compiler that produces a bytecode output
1905 that can be interpreted by the ASN.1 stream decoder and used to
1906 inform it as to what tags are to be expected in a stream and what
1907 functions to call on what tags.
1909 source "kernel/Kconfig.locks"
git.samba.org / sfrench / cifs-2.6.git / blob