ar71xx: fix spelling in mach-rb922.c
[openwrt/openwrt.git] / config / Config-kernel.in
1 # Copyright (C) 2006-2014 OpenWrt.org
2 #
3 # This is free software, licensed under the GNU General Public License v2.
4 # See /LICENSE for more information.
5 #
6
7 config KERNEL_BUILD_USER
8 string "Custom Kernel Build User Name"
9 default ""
10 help
11 Sets the Kernel build user string, which for example will be returned
12 by 'uname -a' on running systems.
13 If not set, uses system user at build time.
14
15 config KERNEL_BUILD_DOMAIN
16 string "Custom Kernel Build Domain Name"
17 default ""
18 help
19 Sets the Kernel build domain string, which for example will be
20 returned by 'uname -a' on running systems.
21 If not set, uses system hostname at build time.
22
23 config KERNEL_PRINTK
24 bool "Enable support for printk"
25 default y
26
27 config KERNEL_CRASHLOG
28 bool "Crash logging"
29 depends on !(arm || powerpc || sparc || TARGET_uml || i386 || x86_64)
30 default y
31
32 config KERNEL_SWAP
33 bool "Support for paging of anonymous memory (swap)"
34 default y
35
36 config KERNEL_DEBUG_FS
37 bool "Compile the kernel with debug filesystem enabled"
38 default y
39 help
40 debugfs is a virtual file system that kernel developers use to put
41 debugging files into. Enable this option to be able to read and
42 write to these files. Many common debugging facilities, such as
43 ftrace, require the existence of debugfs.
44
45 config KERNEL_ARM_PMU
46 bool
47 default n
48 depends on (arm || arm64)
49
50 config KERNEL_PERF_EVENTS
51 bool "Compile the kernel with performance events and counters"
52 default n
53 select KERNEL_ARM_PMU if (arm || arm64)
54
55 config KERNEL_PROFILING
56 bool "Compile the kernel with profiling enabled"
57 default n
58 select KERNEL_PERF_EVENTS
59 help
60 Enable the extended profiling support mechanisms used by profilers such
61 as OProfile.
62
63 config KERNEL_KALLSYMS
64 bool "Compile the kernel with symbol table information"
65 default y if !SMALL_FLASH
66 help
67 This will give you more information in stack traces from kernel oopses.
68
69 config KERNEL_FTRACE
70 bool "Compile the kernel with tracing support"
71 depends on !TARGET_uml
72 default n
73
74 config KERNEL_FTRACE_SYSCALLS
75 bool "Trace system calls"
76 depends on KERNEL_FTRACE
77 default n
78
79 config KERNEL_ENABLE_DEFAULT_TRACERS
80 bool "Trace process context switches and events"
81 depends on KERNEL_FTRACE
82 default n
83
84 config KERNEL_FUNCTION_TRACER
85 bool "Function tracer"
86 depends on KERNEL_FTRACE
87 default n
88
89 config KERNEL_FUNCTION_GRAPH_TRACER
90 bool "Function graph tracer"
91 depends on KERNEL_FUNCTION_TRACER
92 default n
93
94 config KERNEL_DYNAMIC_FTRACE
95 bool "Enable/disable function tracing dynamically"
96 depends on KERNEL_FUNCTION_TRACER
97 default n
98
99 config KERNEL_FUNCTION_PROFILER
100 bool "Function profiler"
101 depends on KERNEL_FUNCTION_TRACER
102 default n
103
104 config KERNEL_DEBUG_KERNEL
105 bool
106 default n
107
108 config KERNEL_DEBUG_INFO
109 bool "Compile the kernel with debug information"
110 default y
111 select KERNEL_DEBUG_KERNEL
112 help
113 This will compile your kernel and modules with debug information.
114
115 config KERNEL_DEBUG_LL_UART_NONE
116 bool
117 default n
118 depends on arm
119
120 config KERNEL_DEBUG_LL
121 bool
122 default n
123 depends on arm
124 select KERNEL_DEBUG_LL_UART_NONE
125 help
126 ARM low level debugging.
127
128 config KERNEL_DYNAMIC_DEBUG
129 bool "Compile the kernel with dynamic printk"
130 select KERNEL_DEBUG_FS
131 default n
132 help
133 Compiles debug level messages into the kernel, which would not
134 otherwise be available at runtime. These messages can then be
135 enabled/disabled based on various levels of scope - per source file,
136 function, module, format string, and line number. This mechanism
137 implicitly compiles in all pr_debug() and dev_dbg() calls, which
138 enlarges the kernel text size by about 2%.
139
140 config KERNEL_EARLY_PRINTK
141 bool "Compile the kernel with early printk"
142 default y if TARGET_bcm53xx
143 default n
144 depends on arm
145 select KERNEL_DEBUG_KERNEL
146 select KERNEL_DEBUG_LL if arm
147 help
148 Compile the kernel with early printk support. This is only useful for
149 debugging purposes to send messages over the serial console in early boot.
150 Enable this to debug early boot problems.
151
152 config KERNEL_KPROBES
153 bool "Compile the kernel with kprobes support"
154 default n
155 select KERNEL_FTRACE
156 select KERNEL_PERF_EVENTS
157 help
158 Compiles the kernel with KPROBES support, which allows you to trap
159 at almost any kernel address and execute a callback function.
160 register_kprobe() establishes a probepoint and specifies the
161 callback. Kprobes is useful for kernel debugging, non-intrusive
162 instrumentation and testing.
163 If in doubt, say "N".
164
165 config KERNEL_KPROBE_EVENT
166 bool
167 default y if KERNEL_KPROBES
168
169 config KERNEL_AIO
170 bool "Compile the kernel with asynchronous IO support"
171 default n
172
173 config KERNEL_FHANDLE
174 bool "Compile the kernel with support for fhandle syscalls"
175 default n
176
177 config KERNEL_FANOTIFY
178 bool "Compile the kernel with modern file notification support"
179 default n
180
181 config KERNEL_BLK_DEV_BSG
182 bool "Compile the kernel with SCSI generic v4 support for any block device"
183 default n
184
185 config KERNEL_MAGIC_SYSRQ
186 bool "Compile the kernel with SysRq support"
187 default y
188
189 config KERNEL_DEBUG_PINCTRL
190 bool "Compile the kernel with pinctrl debugging"
191 select KERNEL_DEBUG_KERNEL
192
193 config KERNEL_DEBUG_GPIO
194 bool "Compile the kernel with gpio debugging"
195 select KERNEL_DEBUG_KERNEL
196
197 config KERNEL_COREDUMP
198 bool
199
200 config KERNEL_ELF_CORE
201 bool "Enable process core dump support"
202 select KERNEL_COREDUMP
203 default y
204
205 config KERNEL_PROVE_LOCKING
206 bool "Enable kernel lock checking"
207 select KERNEL_DEBUG_KERNEL
208 default n
209
210 config KERNEL_PRINTK_TIME
211 bool "Enable printk timestamps"
212 default y
213
214 config KERNEL_SLUB_DEBUG
215 bool
216
217 config KERNEL_SLUB_DEBUG_ON
218 bool
219
220 config KERNEL_SLABINFO
221 select KERNEL_SLUB_DEBUG
222 select KERNEL_SLUB_DEBUG_ON
223 bool "Enable /proc slab debug info"
224
225 config KERNEL_PROC_PAGE_MONITOR
226 bool "Enable /proc page monitoring"
227
228 config KERNEL_RELAY
229 bool
230
231 config KERNEL_KEXEC
232 bool "Enable kexec support"
233
234 config KERNEL_PROC_VMCORE
235 bool
236
237 config KERNEL_CRASH_DUMP
238 depends on i386 || x86_64 || arm || armeb
239 select KERNEL_KEXEC
240 select KERNEL_PROC_VMCORE
241 bool "Enable support for kexec crashdump"
242 default y
243
244 config USE_RFKILL
245 bool "Enable rfkill support"
246 default RFKILL_SUPPORT
247
248 config USE_SPARSE
249 bool "Enable sparse check during kernel build"
250 default n
251
252 config KERNEL_DEVTMPFS
253 bool "Compile the kernel with device tmpfs enabled"
254 default n
255 help
256 devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
257 devices nodes for all registered devices to simplify boot, but leaves more
258 complex tasks to userspace (e.g. udev).
259
260 if KERNEL_DEVTMPFS
261
262 config KERNEL_DEVTMPFS_MOUNT
263 bool "Automatically mount devtmpfs after root filesystem is mounted"
264 default n
265
266 endif
267
268 config KERNEL_KEYS
269 bool "Enable kernel access key retention support"
270 default n
271
272 config KERNEL_PERSISTENT_KEYRINGS
273 bool "Enable kernel persistent keyrings"
274 depends on KERNEL_KEYS
275 default n
276
277 config KERNEL_BIG_KEYS
278 bool "Enable large payload keys on kernel keyrings"
279 depends on KERNEL_KEYS
280 default n
281
282 config KERNEL_ENCRYPTED_KEYS
283 tristate "Enable keys with encrypted payloads on kernel keyrings"
284 depends on KERNEL_KEYS
285 default n
286
287 #
288 # CGROUP support symbols
289 #
290
291 config KERNEL_CGROUPS
292 bool "Enable kernel cgroups"
293 default n
294
295 if KERNEL_CGROUPS
296
297 config KERNEL_CGROUP_DEBUG
298 bool "Example debug cgroup subsystem"
299 default n
300 help
301 This option enables a simple cgroup subsystem that
302 exports useful debugging information about the cgroups
303 framework.
304
305 config KERNEL_FREEZER
306 bool
307 default y if KERNEL_CGROUP_FREEZER
308
309 config KERNEL_CGROUP_FREEZER
310 bool "Freezer cgroup subsystem"
311 default y
312 help
313 Provides a way to freeze and unfreeze all tasks in a
314 cgroup.
315
316 config KERNEL_CGROUP_DEVICE
317 bool "Device controller for cgroups"
318 default y
319 help
320 Provides a cgroup implementing whitelists for devices which
321 a process in the cgroup can mknod or open.
322
323 config KERNEL_CGROUP_PIDS
324 bool "PIDs cgroup subsystem"
325 default y
326 help
327 Provides enforcement of process number limits in the scope of a
328 cgroup.
329
330 config KERNEL_CPUSETS
331 bool "Cpuset support"
332 default n
333 help
334 This option will let you create and manage CPUSETs which
335 allow dynamically partitioning a system into sets of CPUs and
336 Memory Nodes and assigning tasks to run only within those sets.
337 This is primarily useful on large SMP or NUMA systems.
338
339 config KERNEL_PROC_PID_CPUSET
340 bool "Include legacy /proc/<pid>/cpuset file"
341 default n
342 depends on KERNEL_CPUSETS
343
344 config KERNEL_CGROUP_CPUACCT
345 bool "Simple CPU accounting cgroup subsystem"
346 default n
347 help
348 Provides a simple Resource Controller for monitoring the
349 total CPU consumed by the tasks in a cgroup.
350
351 config KERNEL_RESOURCE_COUNTERS
352 bool "Resource counters"
353 default n
354 help
355 This option enables controller independent resource accounting
356 infrastructure that works with cgroups.
357
358 config KERNEL_MM_OWNER
359 bool
360 default y if KERNEL_MEMCG
361
362 config KERNEL_MEMCG
363 bool "Memory Resource Controller for Control Groups"
364 default n
365 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
366 help
367 Provides a memory resource controller that manages both anonymous
368 memory and page cache. (See Documentation/cgroups/memory.txt)
369
370 Note that setting this option increases fixed memory overhead
371 associated with each page of memory in the system. By this,
372 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
373 usage tracking struct at boot. Total amount of this is printed out
374 at boot.
375
376 Only enable when you're ok with these tradeoffs and really
377 sure you need the memory resource controller. Even when you enable
378 this, you can set "cgroup_disable=memory" at your boot option to
379 disable memory resource controller and you can avoid overheads
380 (but lose benefits of memory resource controller).
381
382 This config option also selects MM_OWNER config option, which
383 could in turn add some fork/exit overhead.
384
385 config KERNEL_MEMCG_SWAP
386 bool "Memory Resource Controller Swap Extension"
387 default n
388 depends on KERNEL_MEMCG
389 help
390 Add swap management feature to memory resource controller. When you
391 enable this, you can limit mem+swap usage per cgroup. In other words,
392 when you disable this, memory resource controller has no cares to
393 usage of swap...a process can exhaust all of the swap. This extension
394 is useful when you want to avoid exhaustion swap but this itself
395 adds more overheads and consumes memory for remembering information.
396 Especially if you use 32bit system or small memory system, please
397 be careful about enabling this. When memory resource controller
398 is disabled by boot option, this will be automatically disabled and
399 there will be no overhead from this. Even when you set this config=y,
400 if boot option "swapaccount=0" is set, swap will not be accounted.
401 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
402 size is 4096bytes, 512k per 1Gbytes of swap.
403
404 config KERNEL_MEMCG_SWAP_ENABLED
405 bool "Memory Resource Controller Swap Extension enabled by default"
406 default n
407 depends on KERNEL_MEMCG_SWAP
408 help
409 Memory Resource Controller Swap Extension comes with its price in
410 a bigger memory consumption. General purpose distribution kernels
411 which want to enable the feature but keep it disabled by default
412 and let the user enable it by swapaccount boot command line
413 parameter should have this option unselected.
414
415 Those who want to have the feature enabled by default should
416 select this option (if, for some reason, they need to disable it,
417 then swapaccount=0 does the trick).
418
419
420 config KERNEL_MEMCG_KMEM
421 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
422 default n
423 depends on KERNEL_MEMCG
424 help
425 The Kernel Memory extension for Memory Resource Controller can limit
426 the amount of memory used by kernel objects in the system. Those are
427 fundamentally different from the entities handled by the standard
428 Memory Controller, which are page-based, and can be swapped. Users of
429 the kmem extension can use it to guarantee that no group of processes
430 will ever exhaust kernel resources alone.
431
432 config KERNEL_CGROUP_PERF
433 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
434 select KERNEL_PERF_EVENTS
435 default n
436 help
437 This option extends the per-cpu mode to restrict monitoring to
438 threads which belong to the cgroup specified and run on the
439 designated cpu.
440
441 menuconfig KERNEL_CGROUP_SCHED
442 bool "Group CPU scheduler"
443 default n
444 help
445 This feature lets CPU scheduler recognize task groups and control CPU
446 bandwidth allocation to such task groups. It uses cgroups to group
447 tasks.
448
449 if KERNEL_CGROUP_SCHED
450
451 config KERNEL_FAIR_GROUP_SCHED
452 bool "Group scheduling for SCHED_OTHER"
453 default n
454
455 config KERNEL_CFS_BANDWIDTH
456 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
457 default n
458 depends on KERNEL_FAIR_GROUP_SCHED
459 help
460 This option allows users to define CPU bandwidth rates (limits) for
461 tasks running within the fair group scheduler. Groups with no limit
462 set are considered to be unconstrained and will run with no
463 restriction.
464 See tip/Documentation/scheduler/sched-bwc.txt for more information.
465
466 config KERNEL_RT_GROUP_SCHED
467 bool "Group scheduling for SCHED_RR/FIFO"
468 default n
469 help
470 This feature lets you explicitly allocate real CPU bandwidth
471 to task groups. If enabled, it will also make it impossible to
472 schedule realtime tasks for non-root users until you allocate
473 realtime bandwidth for them.
474
475 endif
476
477 config KERNEL_BLK_CGROUP
478 bool "Block IO controller"
479 default y
480 help
481 Generic block IO controller cgroup interface. This is the common
482 cgroup interface which should be used by various IO controlling
483 policies.
484
485 Currently, CFQ IO scheduler uses it to recognize task groups and
486 control disk bandwidth allocation (proportional time slice allocation)
487 to such task groups. It is also used by bio throttling logic in
488 block layer to implement upper limit in IO rates on a device.
489
490 This option only enables generic Block IO controller infrastructure.
491 One needs to also enable actual IO controlling logic/policy. For
492 enabling proportional weight division of disk bandwidth in CFQ, set
493 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
494 CONFIG_BLK_DEV_THROTTLING=y.
495
496 config KERNEL_DEBUG_BLK_CGROUP
497 bool "Enable Block IO controller debugging"
498 default n
499 depends on KERNEL_BLK_CGROUP
500 help
501 Enable some debugging help. Currently it exports additional stat
502 files in a cgroup which can be useful for debugging.
503
504 config KERNEL_NET_CLS_CGROUP
505 bool "Control Group Classifier"
506 default y
507
508 config KERNEL_NETPRIO_CGROUP
509 bool "Network priority cgroup"
510 default y
511
512 endif
513
514 #
515 # Namespace support symbols
516 #
517
518 config KERNEL_NAMESPACES
519 bool "Enable kernel namespaces"
520 default n
521
522 if KERNEL_NAMESPACES
523
524 config KERNEL_UTS_NS
525 bool "UTS namespace"
526 default y
527 help
528 In this namespace, tasks see different info provided
529 with the uname() system call.
530
531 config KERNEL_IPC_NS
532 bool "IPC namespace"
533 default y
534 help
535 In this namespace, tasks work with IPC ids which correspond to
536 different IPC objects in different namespaces.
537
538 config KERNEL_USER_NS
539 bool "User namespace (EXPERIMENTAL)"
540 default y
541 help
542 This allows containers, i.e. vservers, to use user namespaces
543 to provide different user info for different servers.
544
545 config KERNEL_PID_NS
546 bool "PID Namespaces"
547 default y
548 help
549 Support process id namespaces. This allows having multiple
550 processes with the same pid as long as they are in different
551 pid namespaces. This is a building block of containers.
552
553 config KERNEL_NET_NS
554 bool "Network namespace"
555 default y
556 help
557 Allow user space to create what appear to be multiple instances
558 of the network stack.
559
560 endif
561
562 #
563 # LXC related symbols
564 #
565
566 config KERNEL_LXC_MISC
567 bool "Enable miscellaneous LXC related options"
568 default n
569
570 if KERNEL_LXC_MISC
571
572 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
573 bool "Support multiple instances of devpts"
574 default y
575 help
576 Enable support for multiple instances of devpts filesystem.
577 If you want to have isolated PTY namespaces (eg: in containers),
578 say Y here. Otherwise, say N. If enabled, each mount of devpts
579 filesystem with the '-o newinstance' option will create an
580 independent PTY namespace.
581
582 config KERNEL_POSIX_MQUEUE
583 bool "POSIX Message Queues"
584 default y
585 help
586 POSIX variant of message queues is a part of IPC. In POSIX message
587 queues every message has a priority which decides about succession
588 of receiving it by a process. If you want to compile and run
589 programs written e.g. for Solaris with use of its POSIX message
590 queues (functions mq_*) say Y here.
591
592 POSIX message queues are visible as a filesystem called 'mqueue'
593 and can be mounted somewhere if you want to do filesystem
594 operations on message queues.
595
596 endif
597
598 config KERNEL_SECCOMP_FILTER
599 bool
600 default n
601
602 config KERNEL_SECCOMP
603 bool "Enable seccomp support"
604 depends on !(TARGET_uml)
605 select KERNEL_SECCOMP_FILTER
606 default n
607 help
608 Build kernel with support for seccomp.
609
610 #
611 # IPv6 configuration
612 #
613
614 config KERNEL_IPV6
615 def_bool IPV6
616
617 if KERNEL_IPV6
618
619 config KERNEL_IPV6_MULTIPLE_TABLES
620 def_bool y
621
622 config KERNEL_IPV6_SUBTREES
623 def_bool y
624
625 config KERNEL_IPV6_MROUTE
626 def_bool y
627
628 config KERNEL_IPV6_PIMSM_V2
629 def_bool n
630
631 endif
632
633 #
634 # NFS related symbols
635 #
636 config KERNEL_IP_PNP
637 bool "Compile the kernel with rootfs on NFS"
638 help
639 If you want to make your kernel boot off a NFS server as root
640 filesystem, select Y here.
641
642 if KERNEL_IP_PNP
643
644 config KERNEL_IP_PNP_DHCP
645 def_bool y
646
647 config KERNEL_IP_PNP_BOOTP
648 def_bool n
649
650 config KERNEL_IP_PNP_RARP
651 def_bool n
652
653 config KERNEL_NFS_FS
654 def_bool y
655
656 config KERNEL_NFS_V2
657 def_bool y
658
659 config KERNEL_NFS_V3
660 def_bool y
661
662 config KERNEL_ROOT_NFS
663 def_bool y
664
665 endif
666
667 menu "Filesystem ACL and attr support options"
668 config USE_FS_ACL_ATTR
669 bool "Use filesystem ACL and attr support by default"
670 default n
671 help
672 Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
673 for kernel and packages, except tmpfs, flash filesystems,
674 and old NFS. Also enable userspace extended attribute support
675 by default. (OpenWrt already has an expection it will be
676 present in the kernel).
677
678 config KERNEL_FS_POSIX_ACL
679 bool "Enable POSIX ACL support"
680 default y if USE_FS_ACL_ATTR
681
682 config KERNEL_BTRFS_FS_POSIX_ACL
683 bool "Enable POSIX ACL for BtrFS Filesystems"
684 select KERNEL_FS_POSIX_ACL
685 default y if USE_FS_ACL_ATTR
686
687 config KERNEL_EXT4_FS_POSIX_ACL
688 bool "Enable POSIX ACL for Ext4 Filesystems"
689 select KERNEL_FS_POSIX_ACL
690 default y if USE_FS_ACL_ATTR
691
692 config KERNEL_F2FS_FS_POSIX_ACL
693 bool "Enable POSIX ACL for F2FS Filesystems"
694 select KERNEL_FS_POSIX_ACL
695 default n
696
697 config KERNEL_JFFS2_FS_POSIX_ACL
698 bool "Enable POSIX ACL for JFFS2 Filesystems"
699 select KERNEL_FS_POSIX_ACL
700 default n
701
702 config KERNEL_TMPFS_POSIX_ACL
703 bool "Enable POSIX ACL for TMPFS Filesystems"
704 select KERNEL_FS_POSIX_ACL
705 default n
706
707 config KERNEL_CIFS_ACL
708 bool "Enable CIFS ACLs"
709 select KERNEL_FS_POSIX_ACL
710 default y if USE_FS_ACL_ATTR
711
712 config KERNEL_HFS_FS_POSIX_ACL
713 bool "Enable POSIX ACL for HFS Filesystems"
714 select KERNEL_FS_POSIX_ACL
715 default y if USE_FS_ACL_ATTR
716
717 config KERNEL_HFSPLUG_FS_POSIX_ACL
718 bool "Enable POSIX ACL for HFS+ Filesystems"
719 select KERNEL_FS_POSIX_ACL
720 default y if USE_FS_ACL_ATTR
721
722 config KERNEL_NFS_ACL_SUPPORT
723 bool "Enable ACLs for NFS"
724 default y if USE_FS_ACL_ATTR
725
726 config KERNEL_NFS_V3_ACL_SUPPORT
727 bool "Enable ACLs for NFSv3"
728 default n
729
730 config KERNEL_NFSD_V2_ACL_SUPPORT
731 bool "Enable ACLs for NFSDv2"
732 default n
733
734 config KERNEL_NFSD_V3_ACL_SUPPORT
735 bool "Enable ACLs for NFSDv3"
736 default n
737
738 config KERNEL_REISER_FS_POSIX_ACL
739 bool "Enable POSIX ACLs for ReiserFS"
740 select KERNEL_FS_POSIX_ACL
741 default y if USE_FS_ACL_ATTR
742
743 config KERNEL_XFS_POSIX_ACL
744 bool "Enable POSIX ACLs for XFS"
745 select KERNEL_FS_POSIX_ACL
746 default y if USE_FS_ACL_ATTR
747
748 config KERNEL_JFS_POSIX_ACL
749 bool "Enable POSIX ACLs for JFS"
750 select KERNEL_FS_POSIX_ACL
751 default y if USE_FS_ACL_ATTR
752
753 endmenu
754
755 config KERNEL_DEVMEM
756 bool "/dev/mem virtual device support"
757 help
758 Say Y here if you want to support the /dev/mem device.
759 The /dev/mem device is used to access areas of physical
760 memory.
761
762 config KERNEL_DEVKMEM
763 bool "/dev/kmem virtual device support"
764 help
765 Say Y here if you want to support the /dev/kmem device. The
766 /dev/kmem device is rarely used, but can be used for certain
767 kind of kernel debugging operations.