xref: /openbmc/linux/init/Kconfig (revision 84764a41)
1config ARCH
2	string
3	option env="ARCH"
4
5config KERNELVERSION
6	string
7	option env="KERNELVERSION"
8
9config DEFCONFIG_LIST
10	string
11	depends on !UML
12	option defconfig_list
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"
18
19config CONSTRUCTORS
20	bool
21	depends on !UML
22
23config HAVE_IRQ_WORK
24	bool
25
26config IRQ_WORK
27	bool
28	depends on HAVE_IRQ_WORK
29
30config BUILDTIME_EXTABLE_SORT
31	bool
32
33menu "General setup"
34
35config EXPERIMENTAL
36	bool "Prompt for development and/or incomplete code/drivers"
37	---help---
38	  Some of the various things that Linux supports (such as network
39	  drivers, file systems, network protocols, etc.) can be in a state
40	  of development where the functionality, stability, or the level of
41	  testing is not yet high enough for general use. This is usually
42	  known as the "alpha-test" phase among developers. If a feature is
43	  currently in alpha-test, then the developers usually discourage
44	  uninformed widespread use of this feature by the general public to
45	  avoid "Why doesn't this work?" type mail messages. However, active
46	  testing and use of these systems is welcomed. Just be aware that it
47	  may not meet the normal level of reliability or it may fail to work
48	  in some special cases. Detailed bug reports from people familiar
49	  with the kernel internals are usually welcomed by the developers
50	  (before submitting bug reports, please read the documents
51	  <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
52	  <file:Documentation/BUG-HUNTING>, and
53	  <file:Documentation/oops-tracing.txt> in the kernel source).
54
55	  This option will also make obsoleted drivers available. These are
56	  drivers that have been replaced by something else, and/or are
57	  scheduled to be removed in a future kernel release.
58
59	  Unless you intend to help test and develop a feature or driver that
60	  falls into this category, or you have a situation that requires
61	  using these features, you should probably say N here, which will
62	  cause the configurator to present you with fewer choices. If
63	  you say Y here, you will be offered the choice of using features or
64	  drivers that are currently considered to be in the alpha-test phase.
65
66config BROKEN
67	bool
68
69config BROKEN_ON_SMP
70	bool
71	depends on BROKEN || !SMP
72	default y
73
74config INIT_ENV_ARG_LIMIT
75	int
76	default 32 if !UML
77	default 128 if UML
78	help
79	  Maximum of each of the number of arguments and environment
80	  variables passed to init from the kernel command line.
81
82
83config CROSS_COMPILE
84	string "Cross-compiler tool prefix"
85	help
86	  Same as running 'make CROSS_COMPILE=prefix-' but stored for
87	  default make runs in this kernel build directory.  You don't
88	  need to set this unless you want the configured kernel build
89	  directory to select the cross-compiler automatically.
90
91config LOCALVERSION
92	string "Local version - append to kernel release"
93	help
94	  Append an extra string to the end of your kernel version.
95	  This will show up when you type uname, for example.
96	  The string you set here will be appended after the contents of
97	  any files with a filename matching localversion* in your
98	  object and source tree, in that order.  Your total string can
99	  be a maximum of 64 characters.
100
101config LOCALVERSION_AUTO
102	bool "Automatically append version information to the version string"
103	default y
104	help
105	  This will try to automatically determine if the current tree is a
106	  release tree by looking for git tags that belong to the current
107	  top of tree revision.
108
109	  A string of the format -gxxxxxxxx will be added to the localversion
110	  if a git-based tree is found.  The string generated by this will be
111	  appended after any matching localversion* files, and after the value
112	  set in CONFIG_LOCALVERSION.
113
114	  (The actual string used here is the first eight characters produced
115	  by running the command:
116
117	    $ git rev-parse --verify HEAD
118
119	  which is done within the script "scripts/setlocalversion".)
120
121config HAVE_KERNEL_GZIP
122	bool
123
124config HAVE_KERNEL_BZIP2
125	bool
126
127config HAVE_KERNEL_LZMA
128	bool
129
130config HAVE_KERNEL_XZ
131	bool
132
133config HAVE_KERNEL_LZO
134	bool
135
136choice
137	prompt "Kernel compression mode"
138	default KERNEL_GZIP
139	depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
140	help
141	  The linux kernel is a kind of self-extracting executable.
142	  Several compression algorithms are available, which differ
143	  in efficiency, compression and decompression speed.
144	  Compression speed is only relevant when building a kernel.
145	  Decompression speed is relevant at each boot.
146
147	  If you have any problems with bzip2 or lzma compressed
148	  kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
149	  version of this functionality (bzip2 only), for 2.4, was
150	  supplied by Christian Ludwig)
151
152	  High compression options are mostly useful for users, who
153	  are low on disk space (embedded systems), but for whom ram
154	  size matters less.
155
156	  If in doubt, select 'gzip'
157
158config KERNEL_GZIP
159	bool "Gzip"
160	depends on HAVE_KERNEL_GZIP
161	help
162	  The old and tried gzip compression. It provides a good balance
163	  between compression ratio and decompression speed.
164
165config KERNEL_BZIP2
166	bool "Bzip2"
167	depends on HAVE_KERNEL_BZIP2
168	help
169	  Its compression ratio and speed is intermediate.
170	  Decompression speed is slowest among the choices.  The kernel
171	  size is about 10% smaller with bzip2, in comparison to gzip.
172	  Bzip2 uses a large amount of memory. For modern kernels you
173	  will need at least 8MB RAM or more for booting.
174
175config KERNEL_LZMA
176	bool "LZMA"
177	depends on HAVE_KERNEL_LZMA
178	help
179	  This compression algorithm's ratio is best.  Decompression speed
180	  is between gzip and bzip2.  Compression is slowest.
181	  The kernel size is about 33% smaller with LZMA in comparison to gzip.
182
183config KERNEL_XZ
184	bool "XZ"
185	depends on HAVE_KERNEL_XZ
186	help
187	  XZ uses the LZMA2 algorithm and instruction set specific
188	  BCJ filters which can improve compression ratio of executable
189	  code. The size of the kernel is about 30% smaller with XZ in
190	  comparison to gzip. On architectures for which there is a BCJ
191	  filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
192	  will create a few percent smaller kernel than plain LZMA.
193
194	  The speed is about the same as with LZMA: The decompression
195	  speed of XZ is better than that of bzip2 but worse than gzip
196	  and LZO. Compression is slow.
197
198config KERNEL_LZO
199	bool "LZO"
200	depends on HAVE_KERNEL_LZO
201	help
202	  Its compression ratio is the poorest among the choices. The kernel
203	  size is about 10% bigger than gzip; however its speed
204	  (both compression and decompression) is the fastest.
205
206endchoice
207
208config DEFAULT_HOSTNAME
209	string "Default hostname"
210	default "(none)"
211	help
212	  This option determines the default system hostname before userspace
213	  calls sethostname(2). The kernel traditionally uses "(none)" here,
214	  but you may wish to use a different default here to make a minimal
215	  system more usable with less configuration.
216
217config SWAP
218	bool "Support for paging of anonymous memory (swap)"
219	depends on MMU && BLOCK
220	default y
221	help
222	  This option allows you to choose whether you want to have support
223	  for so called swap devices or swap files in your kernel that are
224	  used to provide more virtual memory than the actual RAM present
225	  in your computer.  If unsure say Y.
226
227config SYSVIPC
228	bool "System V IPC"
229	---help---
230	  Inter Process Communication is a suite of library functions and
231	  system calls which let processes (running programs) synchronize and
232	  exchange information. It is generally considered to be a good thing,
233	  and some programs won't run unless you say Y here. In particular, if
234	  you want to run the DOS emulator dosemu under Linux (read the
235	  DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
236	  you'll need to say Y here.
237
238	  You can find documentation about IPC with "info ipc" and also in
239	  section 6.4 of the Linux Programmer's Guide, available from
240	  <http://www.tldp.org/guides.html>.
241
242config SYSVIPC_SYSCTL
243	bool
244	depends on SYSVIPC
245	depends on SYSCTL
246	default y
247
248config POSIX_MQUEUE
249	bool "POSIX Message Queues"
250	depends on NET && EXPERIMENTAL
251	---help---
252	  POSIX variant of message queues is a part of IPC. In POSIX message
253	  queues every message has a priority which decides about succession
254	  of receiving it by a process. If you want to compile and run
255	  programs written e.g. for Solaris with use of its POSIX message
256	  queues (functions mq_*) say Y here.
257
258	  POSIX message queues are visible as a filesystem called 'mqueue'
259	  and can be mounted somewhere if you want to do filesystem
260	  operations on message queues.
261
262	  If unsure, say Y.
263
264config POSIX_MQUEUE_SYSCTL
265	bool
266	depends on POSIX_MQUEUE
267	depends on SYSCTL
268	default y
269
270config FHANDLE
271	bool "open by fhandle syscalls"
272	select EXPORTFS
273	help
274	  If you say Y here, a user level program will be able to map
275	  file names to handle and then later use the handle for
276	  different file system operations. This is useful in implementing
277	  userspace file servers, which now track files using handles instead
278	  of names. The handle would remain the same even if file names
279	  get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
280	  syscalls.
281
282config AUDIT
283	bool "Auditing support"
284	depends on NET
285	help
286	  Enable auditing infrastructure that can be used with another
287	  kernel subsystem, such as SELinux (which requires this for
288	  logging of avc messages output).  Does not do system-call
289	  auditing without CONFIG_AUDITSYSCALL.
290
291config AUDITSYSCALL
292	bool "Enable system-call auditing support"
293	depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
294	default y if SECURITY_SELINUX
295	help
296	  Enable low-overhead system-call auditing infrastructure that
297	  can be used independently or with another kernel subsystem,
298	  such as SELinux.
299
300config AUDIT_WATCH
301	def_bool y
302	depends on AUDITSYSCALL
303	select FSNOTIFY
304
305config AUDIT_TREE
306	def_bool y
307	depends on AUDITSYSCALL
308	select FSNOTIFY
309
310config AUDIT_LOGINUID_IMMUTABLE
311	bool "Make audit loginuid immutable"
312	depends on AUDIT
313	help
314	  The config option toggles if a task setting its loginuid requires
315	  CAP_SYS_AUDITCONTROL or if that task should require no special permissions
316	  but should instead only allow setting its loginuid if it was never
317	  previously set.  On systems which use systemd or a similar central
318	  process to restart login services this should be set to true.  On older
319	  systems in which an admin would typically have to directly stop and
320	  start processes this should be set to false.  Setting this to true allows
321	  one to drop potentially dangerous capabilites from the login tasks,
322	  but may not be backwards compatible with older init systems.
323
324source "kernel/irq/Kconfig"
325source "kernel/time/Kconfig"
326
327menu "CPU/Task time and stats accounting"
328
329choice
330	prompt "Cputime accounting"
331	default TICK_CPU_ACCOUNTING if !PPC64
332	default VIRT_CPU_ACCOUNTING if PPC64
333
334# Kind of a stub config for the pure tick based cputime accounting
335config TICK_CPU_ACCOUNTING
336	bool "Simple tick based cputime accounting"
337	depends on !S390
338	help
339	  This is the basic tick based cputime accounting that maintains
340	  statistics about user, system and idle time spent on per jiffies
341	  granularity.
342
343	  If unsure, say Y.
344
345config VIRT_CPU_ACCOUNTING
346	bool "Deterministic task and CPU time accounting"
347	depends on HAVE_VIRT_CPU_ACCOUNTING
348	help
349	  Select this option to enable more accurate task and CPU time
350	  accounting.  This is done by reading a CPU counter on each
351	  kernel entry and exit and on transitions within the kernel
352	  between system, softirq and hardirq state, so there is a
353	  small performance impact.  In the case of s390 or IBM POWER > 5,
354	  this also enables accounting of stolen time on logically-partitioned
355	  systems.
356
357config IRQ_TIME_ACCOUNTING
358	bool "Fine granularity task level IRQ time accounting"
359	depends on HAVE_IRQ_TIME_ACCOUNTING
360	help
361	  Select this option to enable fine granularity task irq time
362	  accounting. This is done by reading a timestamp on each
363	  transitions between softirq and hardirq state, so there can be a
364	  small performance impact.
365
366	  If in doubt, say N here.
367
368endchoice
369
370config BSD_PROCESS_ACCT
371	bool "BSD Process Accounting"
372	help
373	  If you say Y here, a user level program will be able to instruct the
374	  kernel (via a special system call) to write process accounting
375	  information to a file: whenever a process exits, information about
376	  that process will be appended to the file by the kernel.  The
377	  information includes things such as creation time, owning user,
378	  command name, memory usage, controlling terminal etc. (the complete
379	  list is in the struct acct in <file:include/linux/acct.h>).  It is
380	  up to the user level program to do useful things with this
381	  information.  This is generally a good idea, so say Y.
382
383config BSD_PROCESS_ACCT_V3
384	bool "BSD Process Accounting version 3 file format"
385	depends on BSD_PROCESS_ACCT
386	default n
387	help
388	  If you say Y here, the process accounting information is written
389	  in a new file format that also logs the process IDs of each
390	  process and it's parent. Note that this file format is incompatible
391	  with previous v0/v1/v2 file formats, so you will need updated tools
392	  for processing it. A preliminary version of these tools is available
393	  at <http://www.gnu.org/software/acct/>.
394
395config TASKSTATS
396	bool "Export task/process statistics through netlink (EXPERIMENTAL)"
397	depends on NET
398	default n
399	help
400	  Export selected statistics for tasks/processes through the
401	  generic netlink interface. Unlike BSD process accounting, the
402	  statistics are available during the lifetime of tasks/processes as
403	  responses to commands. Like BSD accounting, they are sent to user
404	  space on task exit.
405
406	  Say N if unsure.
407
408config TASK_DELAY_ACCT
409	bool "Enable per-task delay accounting (EXPERIMENTAL)"
410	depends on TASKSTATS
411	help
412	  Collect information on time spent by a task waiting for system
413	  resources like cpu, synchronous block I/O completion and swapping
414	  in pages. Such statistics can help in setting a task's priorities
415	  relative to other tasks for cpu, io, rss limits etc.
416
417	  Say N if unsure.
418
419config TASK_XACCT
420	bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
421	depends on TASKSTATS
422	help
423	  Collect extended task accounting data and send the data
424	  to userland for processing over the taskstats interface.
425
426	  Say N if unsure.
427
428config TASK_IO_ACCOUNTING
429	bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
430	depends on TASK_XACCT
431	help
432	  Collect information on the number of bytes of storage I/O which this
433	  task has caused.
434
435	  Say N if unsure.
436
437endmenu # "CPU/Task time and stats accounting"
438
439menu "RCU Subsystem"
440
441choice
442	prompt "RCU Implementation"
443	default TREE_RCU
444
445config TREE_RCU
446	bool "Tree-based hierarchical RCU"
447	depends on !PREEMPT && SMP
448	help
449	  This option selects the RCU implementation that is
450	  designed for very large SMP system with hundreds or
451	  thousands of CPUs.  It also scales down nicely to
452	  smaller systems.
453
454config TREE_PREEMPT_RCU
455	bool "Preemptible tree-based hierarchical RCU"
456	depends on PREEMPT && SMP
457	help
458	  This option selects the RCU implementation that is
459	  designed for very large SMP systems with hundreds or
460	  thousands of CPUs, but for which real-time response
461	  is also required.  It also scales down nicely to
462	  smaller systems.
463
464config TINY_RCU
465	bool "UP-only small-memory-footprint RCU"
466	depends on !PREEMPT && !SMP
467	help
468	  This option selects the RCU implementation that is
469	  designed for UP systems from which real-time response
470	  is not required.  This option greatly reduces the
471	  memory footprint of RCU.
472
473config TINY_PREEMPT_RCU
474	bool "Preemptible UP-only small-memory-footprint RCU"
475	depends on PREEMPT && !SMP
476	help
477	  This option selects the RCU implementation that is designed
478	  for real-time UP systems.  This option greatly reduces the
479	  memory footprint of RCU.
480
481endchoice
482
483config PREEMPT_RCU
484	def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
485	help
486	  This option enables preemptible-RCU code that is common between
487	  the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
488
489config RCU_USER_QS
490	bool "Consider userspace as in RCU extended quiescent state"
491	depends on HAVE_RCU_USER_QS && SMP
492	help
493	  This option sets hooks on kernel / userspace boundaries and
494	  puts RCU in extended quiescent state when the CPU runs in
495	  userspace. It means that when a CPU runs in userspace, it is
496	  excluded from the global RCU state machine and thus doesn't
497	  to keep the timer tick on for RCU.
498
499	  Unless you want to hack and help the development of the full
500	  tickless feature, you shouldn't enable this option. It adds
501	  unnecessary overhead.
502
503	  If unsure say N
504
505config RCU_USER_QS_FORCE
506	bool "Force userspace extended QS by default"
507	depends on RCU_USER_QS
508	help
509	  Set the hooks in user/kernel boundaries by default in order to
510	  test this feature that treats userspace as an extended quiescent
511	  state until we have a real user like a full adaptive nohz option.
512
513	  Unless you want to hack and help the development of the full
514	  tickless feature, you shouldn't enable this option. It adds
515	  unnecessary overhead.
516
517	  If unsure say N
518
519config RCU_FANOUT
520	int "Tree-based hierarchical RCU fanout value"
521	range 2 64 if 64BIT
522	range 2 32 if !64BIT
523	depends on TREE_RCU || TREE_PREEMPT_RCU
524	default 64 if 64BIT
525	default 32 if !64BIT
526	help
527	  This option controls the fanout of hierarchical implementations
528	  of RCU, allowing RCU to work efficiently on machines with
529	  large numbers of CPUs.  This value must be at least the fourth
530	  root of NR_CPUS, which allows NR_CPUS to be insanely large.
531	  The default value of RCU_FANOUT should be used for production
532	  systems, but if you are stress-testing the RCU implementation
533	  itself, small RCU_FANOUT values allow you to test large-system
534	  code paths on small(er) systems.
535
536	  Select a specific number if testing RCU itself.
537	  Take the default if unsure.
538
539config RCU_FANOUT_LEAF
540	int "Tree-based hierarchical RCU leaf-level fanout value"
541	range 2 RCU_FANOUT if 64BIT
542	range 2 RCU_FANOUT if !64BIT
543	depends on TREE_RCU || TREE_PREEMPT_RCU
544	default 16
545	help
546	  This option controls the leaf-level fanout of hierarchical
547	  implementations of RCU, and allows trading off cache misses
548	  against lock contention.  Systems that synchronize their
549	  scheduling-clock interrupts for energy-efficiency reasons will
550	  want the default because the smaller leaf-level fanout keeps
551	  lock contention levels acceptably low.  Very large systems
552	  (hundreds or thousands of CPUs) will instead want to set this
553	  value to the maximum value possible in order to reduce the
554	  number of cache misses incurred during RCU's grace-period
555	  initialization.  These systems tend to run CPU-bound, and thus
556	  are not helped by synchronized interrupts, and thus tend to
557	  skew them, which reduces lock contention enough that large
558	  leaf-level fanouts work well.
559
560	  Select a specific number if testing RCU itself.
561
562	  Select the maximum permissible value for large systems.
563
564	  Take the default if unsure.
565
566config RCU_FANOUT_EXACT
567	bool "Disable tree-based hierarchical RCU auto-balancing"
568	depends on TREE_RCU || TREE_PREEMPT_RCU
569	default n
570	help
571	  This option forces use of the exact RCU_FANOUT value specified,
572	  regardless of imbalances in the hierarchy.  This is useful for
573	  testing RCU itself, and might one day be useful on systems with
574	  strong NUMA behavior.
575
576	  Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
577
578	  Say N if unsure.
579
580config RCU_FAST_NO_HZ
581	bool "Accelerate last non-dyntick-idle CPU's grace periods"
582	depends on NO_HZ && SMP
583	default n
584	help
585	  This option causes RCU to attempt to accelerate grace periods
586	  in order to allow CPUs to enter dynticks-idle state more
587	  quickly.  On the other hand, this option increases the overhead
588	  of the dynticks-idle checking, particularly on systems with
589	  large numbers of CPUs.
590
591	  Say Y if energy efficiency is critically important, particularly
592	  	if you have relatively few CPUs.
593
594	  Say N if you are unsure.
595
596config TREE_RCU_TRACE
597	def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
598	select DEBUG_FS
599	help
600	  This option provides tracing for the TREE_RCU and
601	  TREE_PREEMPT_RCU implementations, permitting Makefile to
602	  trivially select kernel/rcutree_trace.c.
603
604config RCU_BOOST
605	bool "Enable RCU priority boosting"
606	depends on RT_MUTEXES && PREEMPT_RCU
607	default n
608	help
609	  This option boosts the priority of preempted RCU readers that
610	  block the current preemptible RCU grace period for too long.
611	  This option also prevents heavy loads from blocking RCU
612	  callback invocation for all flavors of RCU.
613
614	  Say Y here if you are working with real-time apps or heavy loads
615	  Say N here if you are unsure.
616
617config RCU_BOOST_PRIO
618	int "Real-time priority to boost RCU readers to"
619	range 1 99
620	depends on RCU_BOOST
621	default 1
622	help
623	  This option specifies the real-time priority to which long-term
624	  preempted RCU readers are to be boosted.  If you are working
625	  with a real-time application that has one or more CPU-bound
626	  threads running at a real-time priority level, you should set
627	  RCU_BOOST_PRIO to a priority higher then the highest-priority
628	  real-time CPU-bound thread.  The default RCU_BOOST_PRIO value
629	  of 1 is appropriate in the common case, which is real-time
630	  applications that do not have any CPU-bound threads.
631
632	  Some real-time applications might not have a single real-time
633	  thread that saturates a given CPU, but instead might have
634	  multiple real-time threads that, taken together, fully utilize
635	  that CPU.  In this case, you should set RCU_BOOST_PRIO to
636	  a priority higher than the lowest-priority thread that is
637	  conspiring to prevent the CPU from running any non-real-time
638	  tasks.  For example, if one thread at priority 10 and another
639	  thread at priority 5 are between themselves fully consuming
640	  the CPU time on a given CPU, then RCU_BOOST_PRIO should be
641	  set to priority 6 or higher.
642
643	  Specify the real-time priority, or take the default if unsure.
644
645config RCU_BOOST_DELAY
646	int "Milliseconds to delay boosting after RCU grace-period start"
647	range 0 3000
648	depends on RCU_BOOST
649	default 500
650	help
651	  This option specifies the time to wait after the beginning of
652	  a given grace period before priority-boosting preempted RCU
653	  readers blocking that grace period.  Note that any RCU reader
654	  blocking an expedited RCU grace period is boosted immediately.
655
656	  Accept the default if unsure.
657
658endmenu # "RCU Subsystem"
659
660config IKCONFIG
661	tristate "Kernel .config support"
662	---help---
663	  This option enables the complete Linux kernel ".config" file
664	  contents to be saved in the kernel. It provides documentation
665	  of which kernel options are used in a running kernel or in an
666	  on-disk kernel.  This information can be extracted from the kernel
667	  image file with the script scripts/extract-ikconfig and used as
668	  input to rebuild the current kernel or to build another kernel.
669	  It can also be extracted from a running kernel by reading
670	  /proc/config.gz if enabled (below).
671
672config IKCONFIG_PROC
673	bool "Enable access to .config through /proc/config.gz"
674	depends on IKCONFIG && PROC_FS
675	---help---
676	  This option enables access to the kernel configuration file
677	  through /proc/config.gz.
678
679config LOG_BUF_SHIFT
680	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
681	range 12 21
682	default 17
683	help
684	  Select kernel log buffer size as a power of 2.
685	  Examples:
686	  	     17 => 128 KB
687		     16 => 64 KB
688	             15 => 32 KB
689	             14 => 16 KB
690		     13 =>  8 KB
691		     12 =>  4 KB
692
693#
694# Architectures with an unreliable sched_clock() should select this:
695#
696config HAVE_UNSTABLE_SCHED_CLOCK
697	bool
698
699menuconfig CGROUPS
700	boolean "Control Group support"
701	depends on EVENTFD
702	help
703	  This option adds support for grouping sets of processes together, for
704	  use with process control subsystems such as Cpusets, CFS, memory
705	  controls or device isolation.
706	  See
707		- Documentation/scheduler/sched-design-CFS.txt	(CFS)
708		- Documentation/cgroups/ (features for grouping, isolation
709					  and resource control)
710
711	  Say N if unsure.
712
713if CGROUPS
714
715config CGROUP_DEBUG
716	bool "Example debug cgroup subsystem"
717	default n
718	help
719	  This option enables a simple cgroup subsystem that
720	  exports useful debugging information about the cgroups
721	  framework.
722
723	  Say N if unsure.
724
725config CGROUP_FREEZER
726	bool "Freezer cgroup subsystem"
727	help
728	  Provides a way to freeze and unfreeze all tasks in a
729	  cgroup.
730
731config CGROUP_DEVICE
732	bool "Device controller for cgroups"
733	help
734	  Provides a cgroup implementing whitelists for devices which
735	  a process in the cgroup can mknod or open.
736
737config CPUSETS
738	bool "Cpuset support"
739	help
740	  This option will let you create and manage CPUSETs which
741	  allow dynamically partitioning a system into sets of CPUs and
742	  Memory Nodes and assigning tasks to run only within those sets.
743	  This is primarily useful on large SMP or NUMA systems.
744
745	  Say N if unsure.
746
747config PROC_PID_CPUSET
748	bool "Include legacy /proc/<pid>/cpuset file"
749	depends on CPUSETS
750	default y
751
752config CGROUP_CPUACCT
753	bool "Simple CPU accounting cgroup subsystem"
754	help
755	  Provides a simple Resource Controller for monitoring the
756	  total CPU consumed by the tasks in a cgroup.
757
758config RESOURCE_COUNTERS
759	bool "Resource counters"
760	help
761	  This option enables controller independent resource accounting
762	  infrastructure that works with cgroups.
763
764config MEMCG
765	bool "Memory Resource Controller for Control Groups"
766	depends on RESOURCE_COUNTERS
767	select MM_OWNER
768	help
769	  Provides a memory resource controller that manages both anonymous
770	  memory and page cache. (See Documentation/cgroups/memory.txt)
771
772	  Note that setting this option increases fixed memory overhead
773	  associated with each page of memory in the system. By this,
774	  20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
775	  usage tracking struct at boot. Total amount of this is printed out
776	  at boot.
777
778	  Only enable when you're ok with these trade offs and really
779	  sure you need the memory resource controller. Even when you enable
780	  this, you can set "cgroup_disable=memory" at your boot option to
781	  disable memory resource controller and you can avoid overheads.
782	  (and lose benefits of memory resource controller)
783
784	  This config option also selects MM_OWNER config option, which
785	  could in turn add some fork/exit overhead.
786
787config MEMCG_SWAP
788	bool "Memory Resource Controller Swap Extension"
789	depends on MEMCG && SWAP
790	help
791	  Add swap management feature to memory resource controller. When you
792	  enable this, you can limit mem+swap usage per cgroup. In other words,
793	  when you disable this, memory resource controller has no cares to
794	  usage of swap...a process can exhaust all of the swap. This extension
795	  is useful when you want to avoid exhaustion swap but this itself
796	  adds more overheads and consumes memory for remembering information.
797	  Especially if you use 32bit system or small memory system, please
798	  be careful about enabling this. When memory resource controller
799	  is disabled by boot option, this will be automatically disabled and
800	  there will be no overhead from this. Even when you set this config=y,
801	  if boot option "swapaccount=0" is set, swap will not be accounted.
802	  Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
803	  size is 4096bytes, 512k per 1Gbytes of swap.
804config MEMCG_SWAP_ENABLED
805	bool "Memory Resource Controller Swap Extension enabled by default"
806	depends on MEMCG_SWAP
807	default y
808	help
809	  Memory Resource Controller Swap Extension comes with its price in
810	  a bigger memory consumption. General purpose distribution kernels
811	  which want to enable the feature but keep it disabled by default
812	  and let the user enable it by swapaccount boot command line
813	  parameter should have this option unselected.
814	  For those who want to have the feature enabled by default should
815	  select this option (if, for some reason, they need to disable it
816	  then swapaccount=0 does the trick).
817config MEMCG_KMEM
818	bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
819	depends on MEMCG && EXPERIMENTAL
820	default n
821	help
822	  The Kernel Memory extension for Memory Resource Controller can limit
823	  the amount of memory used by kernel objects in the system. Those are
824	  fundamentally different from the entities handled by the standard
825	  Memory Controller, which are page-based, and can be swapped. Users of
826	  the kmem extension can use it to guarantee that no group of processes
827	  will ever exhaust kernel resources alone.
828
829config CGROUP_HUGETLB
830	bool "HugeTLB Resource Controller for Control Groups"
831	depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
832	default n
833	help
834	  Provides a cgroup Resource Controller for HugeTLB pages.
835	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
836	  The limit is enforced during page fault. Since HugeTLB doesn't
837	  support page reclaim, enforcing the limit at page fault time implies
838	  that, the application will get SIGBUS signal if it tries to access
839	  HugeTLB pages beyond its limit. This requires the application to know
840	  beforehand how much HugeTLB pages it would require for its use. The
841	  control group is tracked in the third page lru pointer. This means
842	  that we cannot use the controller with huge page less than 3 pages.
843
844config CGROUP_PERF
845	bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
846	depends on PERF_EVENTS && CGROUPS
847	help
848	  This option extends the per-cpu mode to restrict monitoring to
849	  threads which belong to the cgroup specified and run on the
850	  designated cpu.
851
852	  Say N if unsure.
853
854menuconfig CGROUP_SCHED
855	bool "Group CPU scheduler"
856	default n
857	help
858	  This feature lets CPU scheduler recognize task groups and control CPU
859	  bandwidth allocation to such task groups. It uses cgroups to group
860	  tasks.
861
862if CGROUP_SCHED
863config FAIR_GROUP_SCHED
864	bool "Group scheduling for SCHED_OTHER"
865	depends on CGROUP_SCHED
866	default CGROUP_SCHED
867
868config CFS_BANDWIDTH
869	bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
870	depends on EXPERIMENTAL
871	depends on FAIR_GROUP_SCHED
872	default n
873	help
874	  This option allows users to define CPU bandwidth rates (limits) for
875	  tasks running within the fair group scheduler.  Groups with no limit
876	  set are considered to be unconstrained and will run with no
877	  restriction.
878	  See tip/Documentation/scheduler/sched-bwc.txt for more information.
879
880config RT_GROUP_SCHED
881	bool "Group scheduling for SCHED_RR/FIFO"
882	depends on EXPERIMENTAL
883	depends on CGROUP_SCHED
884	default n
885	help
886	  This feature lets you explicitly allocate real CPU bandwidth
887	  to task groups. If enabled, it will also make it impossible to
888	  schedule realtime tasks for non-root users until you allocate
889	  realtime bandwidth for them.
890	  See Documentation/scheduler/sched-rt-group.txt for more information.
891
892endif #CGROUP_SCHED
893
894config BLK_CGROUP
895	bool "Block IO controller"
896	depends on BLOCK
897	default n
898	---help---
899	Generic block IO controller cgroup interface. This is the common
900	cgroup interface which should be used by various IO controlling
901	policies.
902
903	Currently, CFQ IO scheduler uses it to recognize task groups and
904	control disk bandwidth allocation (proportional time slice allocation)
905	to such task groups. It is also used by bio throttling logic in
906	block layer to implement upper limit in IO rates on a device.
907
908	This option only enables generic Block IO controller infrastructure.
909	One needs to also enable actual IO controlling logic/policy. For
910	enabling proportional weight division of disk bandwidth in CFQ, set
911	CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
912	CONFIG_BLK_DEV_THROTTLING=y.
913
914	See Documentation/cgroups/blkio-controller.txt for more information.
915
916config DEBUG_BLK_CGROUP
917	bool "Enable Block IO controller debugging"
918	depends on BLK_CGROUP
919	default n
920	---help---
921	Enable some debugging help. Currently it exports additional stat
922	files in a cgroup which can be useful for debugging.
923
924endif # CGROUPS
925
926config CHECKPOINT_RESTORE
927	bool "Checkpoint/restore support" if EXPERT
928	default n
929	help
930	  Enables additional kernel features in a sake of checkpoint/restore.
931	  In particular it adds auxiliary prctl codes to setup process text,
932	  data and heap segment sizes, and a few additional /proc filesystem
933	  entries.
934
935	  If unsure, say N here.
936
937menuconfig NAMESPACES
938	bool "Namespaces support" if EXPERT
939	default !EXPERT
940	help
941	  Provides the way to make tasks work with different objects using
942	  the same id. For example same IPC id may refer to different objects
943	  or same user id or pid may refer to different tasks when used in
944	  different namespaces.
945
946if NAMESPACES
947
948config UTS_NS
949	bool "UTS namespace"
950	default y
951	help
952	  In this namespace tasks see different info provided with the
953	  uname() system call
954
955config IPC_NS
956	bool "IPC namespace"
957	depends on (SYSVIPC || POSIX_MQUEUE)
958	default y
959	help
960	  In this namespace tasks work with IPC ids which correspond to
961	  different IPC objects in different namespaces.
962
963config USER_NS
964	bool "User namespace (EXPERIMENTAL)"
965	depends on EXPERIMENTAL
966	depends on UIDGID_CONVERTED
967	select UIDGID_STRICT_TYPE_CHECKS
968
969	default n
970	help
971	  This allows containers, i.e. vservers, to use user namespaces
972	  to provide different user info for different servers.
973	  If unsure, say N.
974
975config PID_NS
976	bool "PID Namespaces"
977	default y
978	help
979	  Support process id namespaces.  This allows having multiple
980	  processes with the same pid as long as they are in different
981	  pid namespaces.  This is a building block of containers.
982
983config NET_NS
984	bool "Network namespace"
985	depends on NET
986	default y
987	help
988	  Allow user space to create what appear to be multiple instances
989	  of the network stack.
990
991endif # NAMESPACES
992
993config UIDGID_CONVERTED
994	# True if all of the selected software conmponents are known
995	# to have uid_t and gid_t converted to kuid_t and kgid_t
996	# where appropriate and are otherwise safe to use with
997	# the user namespace.
998	bool
999	default y
1000
1001	# Networking
1002	depends on NET_9P = n
1003
1004	# Filesystems
1005	depends on 9P_FS = n
1006	depends on AFS_FS = n
1007	depends on AUTOFS4_FS = n
1008	depends on CEPH_FS = n
1009	depends on CIFS = n
1010	depends on CODA_FS = n
1011	depends on FUSE_FS = n
1012	depends on GFS2_FS = n
1013	depends on NCP_FS = n
1014	depends on NFSD = n
1015	depends on NFS_FS = n
1016	depends on OCFS2_FS = n
1017	depends on XFS_FS = n
1018
1019config UIDGID_STRICT_TYPE_CHECKS
1020	bool "Require conversions between uid/gids and their internal representation"
1021	depends on UIDGID_CONVERTED
1022	default n
1023	help
1024	 While the nececessary conversions are being added to all subsystems this option allows
1025	 the code to continue to build for unconverted subsystems.
1026
1027	 Say Y here if you want the strict type checking enabled
1028
1029config SCHED_AUTOGROUP
1030	bool "Automatic process group scheduling"
1031	select EVENTFD
1032	select CGROUPS
1033	select CGROUP_SCHED
1034	select FAIR_GROUP_SCHED
1035	help
1036	  This option optimizes the scheduler for common desktop workloads by
1037	  automatically creating and populating task groups.  This separation
1038	  of workloads isolates aggressive CPU burners (like build jobs) from
1039	  desktop applications.  Task group autogeneration is currently based
1040	  upon task session.
1041
1042config MM_OWNER
1043	bool
1044
1045config SYSFS_DEPRECATED
1046	bool "Enable deprecated sysfs features to support old userspace tools"
1047	depends on SYSFS
1048	default n
1049	help
1050	  This option adds code that switches the layout of the "block" class
1051	  devices, to not show up in /sys/class/block/, but only in
1052	  /sys/block/.
1053
1054	  This switch is only active when the sysfs.deprecated=1 boot option is
1055	  passed or the SYSFS_DEPRECATED_V2 option is set.
1056
1057	  This option allows new kernels to run on old distributions and tools,
1058	  which might get confused by /sys/class/block/. Since 2007/2008 all
1059	  major distributions and tools handle this just fine.
1060
1061	  Recent distributions and userspace tools after 2009/2010 depend on
1062	  the existence of /sys/class/block/, and will not work with this
1063	  option enabled.
1064
1065	  Only if you are using a new kernel on an old distribution, you might
1066	  need to say Y here.
1067
1068config SYSFS_DEPRECATED_V2
1069	bool "Enable deprecated sysfs features by default"
1070	default n
1071	depends on SYSFS
1072	depends on SYSFS_DEPRECATED
1073	help
1074	  Enable deprecated sysfs by default.
1075
1076	  See the CONFIG_SYSFS_DEPRECATED option for more details about this
1077	  option.
1078
1079	  Only if you are using a new kernel on an old distribution, you might
1080	  need to say Y here. Even then, odds are you would not need it
1081	  enabled, you can always pass the boot option if absolutely necessary.
1082
1083config RELAY
1084	bool "Kernel->user space relay support (formerly relayfs)"
1085	help
1086	  This option enables support for relay interface support in
1087	  certain file systems (such as debugfs).
1088	  It is designed to provide an efficient mechanism for tools and
1089	  facilities to relay large amounts of data from kernel space to
1090	  user space.
1091
1092	  If unsure, say N.
1093
1094config BLK_DEV_INITRD
1095	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1096	depends on BROKEN || !FRV
1097	help
1098	  The initial RAM filesystem is a ramfs which is loaded by the
1099	  boot loader (loadlin or lilo) and that is mounted as root
1100	  before the normal boot procedure. It is typically used to
1101	  load modules needed to mount the "real" root file system,
1102	  etc. See <file:Documentation/initrd.txt> for details.
1103
1104	  If RAM disk support (BLK_DEV_RAM) is also included, this
1105	  also enables initial RAM disk (initrd) support and adds
1106	  15 Kbytes (more on some other architectures) to the kernel size.
1107
1108	  If unsure say Y.
1109
1110if BLK_DEV_INITRD
1111
1112source "usr/Kconfig"
1113
1114endif
1115
1116config CC_OPTIMIZE_FOR_SIZE
1117	bool "Optimize for size"
1118	help
1119	  Enabling this option will pass "-Os" instead of "-O2" to gcc
1120	  resulting in a smaller kernel.
1121
1122	  If unsure, say Y.
1123
1124config SYSCTL
1125	bool
1126
1127config ANON_INODES
1128	bool
1129
1130menuconfig EXPERT
1131	bool "Configure standard kernel features (expert users)"
1132	# Unhide debug options, to make the on-by-default options visible
1133	select DEBUG_KERNEL
1134	help
1135	  This option allows certain base kernel options and settings
1136          to be disabled or tweaked. This is for specialized
1137          environments which can tolerate a "non-standard" kernel.
1138          Only use this if you really know what you are doing.
1139
1140config HAVE_UID16
1141	bool
1142
1143config UID16
1144	bool "Enable 16-bit UID system calls" if EXPERT
1145	depends on HAVE_UID16
1146	default y
1147	help
1148	  This enables the legacy 16-bit UID syscall wrappers.
1149
1150config SYSCTL_SYSCALL
1151	bool "Sysctl syscall support" if EXPERT
1152	depends on PROC_SYSCTL
1153	default n
1154	select SYSCTL
1155	---help---
1156	  sys_sysctl uses binary paths that have been found challenging
1157	  to properly maintain and use.  The interface in /proc/sys
1158	  using paths with ascii names is now the primary path to this
1159	  information.
1160
1161	  Almost nothing using the binary sysctl interface so if you are
1162	  trying to save some space it is probably safe to disable this,
1163	  making your kernel marginally smaller.
1164
1165	  If unsure say N here.
1166
1167config SYSCTL_EXCEPTION_TRACE
1168	bool
1169	help
1170	  Enable support for /proc/sys/debug/exception-trace.
1171
1172config KALLSYMS
1173	 bool "Load all symbols for debugging/ksymoops" if EXPERT
1174	 default y
1175	 help
1176	   Say Y here to let the kernel print out symbolic crash information and
1177	   symbolic stack backtraces. This increases the size of the kernel
1178	   somewhat, as all symbols have to be loaded into the kernel image.
1179
1180config KALLSYMS_ALL
1181	bool "Include all symbols in kallsyms"
1182	depends on DEBUG_KERNEL && KALLSYMS
1183	help
1184	   Normally kallsyms only contains the symbols of functions for nicer
1185	   OOPS messages and backtraces (i.e., symbols from the text and inittext
1186	   sections). This is sufficient for most cases. And only in very rare
1187	   cases (e.g., when a debugger is used) all symbols are required (e.g.,
1188	   names of variables from the data sections, etc).
1189
1190	   This option makes sure that all symbols are loaded into the kernel
1191	   image (i.e., symbols from all sections) in cost of increased kernel
1192	   size (depending on the kernel configuration, it may be 300KiB or
1193	   something like this).
1194
1195	   Say N unless you really need all symbols.
1196
1197config HOTPLUG
1198	def_bool y
1199
1200config PRINTK
1201	default y
1202	bool "Enable support for printk" if EXPERT
1203	help
1204	  This option enables normal printk support. Removing it
1205	  eliminates most of the message strings from the kernel image
1206	  and makes the kernel more or less silent. As this makes it
1207	  very difficult to diagnose system problems, saying N here is
1208	  strongly discouraged.
1209
1210config BUG
1211	bool "BUG() support" if EXPERT
1212	default y
1213	help
1214          Disabling this option eliminates support for BUG and WARN, reducing
1215          the size of your kernel image and potentially quietly ignoring
1216          numerous fatal conditions. You should only consider disabling this
1217          option for embedded systems with no facilities for reporting errors.
1218          Just say Y.
1219
1220config ELF_CORE
1221	depends on COREDUMP
1222	default y
1223	bool "Enable ELF core dumps" if EXPERT
1224	help
1225	  Enable support for generating core dumps. Disabling saves about 4k.
1226
1227
1228config PCSPKR_PLATFORM
1229	bool "Enable PC-Speaker support" if EXPERT
1230	depends on HAVE_PCSPKR_PLATFORM
1231	select I8253_LOCK
1232	default y
1233	help
1234          This option allows to disable the internal PC-Speaker
1235          support, saving some memory.
1236
1237config HAVE_PCSPKR_PLATFORM
1238	bool
1239
1240config BASE_FULL
1241	default y
1242	bool "Enable full-sized data structures for core" if EXPERT
1243	help
1244	  Disabling this option reduces the size of miscellaneous core
1245	  kernel data structures. This saves memory on small machines,
1246	  but may reduce performance.
1247
1248config FUTEX
1249	bool "Enable futex support" if EXPERT
1250	default y
1251	select RT_MUTEXES
1252	help
1253	  Disabling this option will cause the kernel to be built without
1254	  support for "fast userspace mutexes".  The resulting kernel may not
1255	  run glibc-based applications correctly.
1256
1257config EPOLL
1258	bool "Enable eventpoll support" if EXPERT
1259	default y
1260	select ANON_INODES
1261	help
1262	  Disabling this option will cause the kernel to be built without
1263	  support for epoll family of system calls.
1264
1265config SIGNALFD
1266	bool "Enable signalfd() system call" if EXPERT
1267	select ANON_INODES
1268	default y
1269	help
1270	  Enable the signalfd() system call that allows to receive signals
1271	  on a file descriptor.
1272
1273	  If unsure, say Y.
1274
1275config TIMERFD
1276	bool "Enable timerfd() system call" if EXPERT
1277	select ANON_INODES
1278	default y
1279	help
1280	  Enable the timerfd() system call that allows to receive timer
1281	  events on a file descriptor.
1282
1283	  If unsure, say Y.
1284
1285config EVENTFD
1286	bool "Enable eventfd() system call" if EXPERT
1287	select ANON_INODES
1288	default y
1289	help
1290	  Enable the eventfd() system call that allows to receive both
1291	  kernel notification (ie. KAIO) or userspace notifications.
1292
1293	  If unsure, say Y.
1294
1295config SHMEM
1296	bool "Use full shmem filesystem" if EXPERT
1297	default y
1298	depends on MMU
1299	help
1300	  The shmem is an internal filesystem used to manage shared memory.
1301	  It is backed by swap and manages resource limits. It is also exported
1302	  to userspace as tmpfs if TMPFS is enabled. Disabling this
1303	  option replaces shmem and tmpfs with the much simpler ramfs code,
1304	  which may be appropriate on small systems without swap.
1305
1306config AIO
1307	bool "Enable AIO support" if EXPERT
1308	default y
1309	help
1310	  This option enables POSIX asynchronous I/O which may by used
1311          by some high performance threaded applications. Disabling
1312          this option saves about 7k.
1313
1314config EMBEDDED
1315	bool "Embedded system"
1316	select EXPERT
1317	help
1318	  This option should be enabled if compiling the kernel for
1319	  an embedded system so certain expert options are available
1320	  for configuration.
1321
1322config HAVE_PERF_EVENTS
1323	bool
1324	help
1325	  See tools/perf/design.txt for details.
1326
1327config PERF_USE_VMALLOC
1328	bool
1329	help
1330	  See tools/perf/design.txt for details
1331
1332menu "Kernel Performance Events And Counters"
1333
1334config PERF_EVENTS
1335	bool "Kernel performance events and counters"
1336	default y if PROFILING
1337	depends on HAVE_PERF_EVENTS
1338	select ANON_INODES
1339	select IRQ_WORK
1340	help
1341	  Enable kernel support for various performance events provided
1342	  by software and hardware.
1343
1344	  Software events are supported either built-in or via the
1345	  use of generic tracepoints.
1346
1347	  Most modern CPUs support performance events via performance
1348	  counter registers. These registers count the number of certain
1349	  types of hw events: such as instructions executed, cachemisses
1350	  suffered, or branches mis-predicted - without slowing down the
1351	  kernel or applications. These registers can also trigger interrupts
1352	  when a threshold number of events have passed - and can thus be
1353	  used to profile the code that runs on that CPU.
1354
1355	  The Linux Performance Event subsystem provides an abstraction of
1356	  these software and hardware event capabilities, available via a
1357	  system call and used by the "perf" utility in tools/perf/. It
1358	  provides per task and per CPU counters, and it provides event
1359	  capabilities on top of those.
1360
1361	  Say Y if unsure.
1362
1363config DEBUG_PERF_USE_VMALLOC
1364	default n
1365	bool "Debug: use vmalloc to back perf mmap() buffers"
1366	depends on PERF_EVENTS && DEBUG_KERNEL
1367	select PERF_USE_VMALLOC
1368	help
1369	 Use vmalloc memory to back perf mmap() buffers.
1370
1371	 Mostly useful for debugging the vmalloc code on platforms
1372	 that don't require it.
1373
1374	 Say N if unsure.
1375
1376endmenu
1377
1378config VM_EVENT_COUNTERS
1379	default y
1380	bool "Enable VM event counters for /proc/vmstat" if EXPERT
1381	help
1382	  VM event counters are needed for event counts to be shown.
1383	  This option allows the disabling of the VM event counters
1384	  on EXPERT systems.  /proc/vmstat will only show page counts
1385	  if VM event counters are disabled.
1386
1387config PCI_QUIRKS
1388	default y
1389	bool "Enable PCI quirk workarounds" if EXPERT
1390	depends on PCI
1391	help
1392	  This enables workarounds for various PCI chipset
1393          bugs/quirks. Disable this only if your target machine is
1394          unaffected by PCI quirks.
1395
1396config SLUB_DEBUG
1397	default y
1398	bool "Enable SLUB debugging support" if EXPERT
1399	depends on SLUB && SYSFS
1400	help
1401	  SLUB has extensive debug support features. Disabling these can
1402	  result in significant savings in code size. This also disables
1403	  SLUB sysfs support. /sys/slab will not exist and there will be
1404	  no support for cache validation etc.
1405
1406config COMPAT_BRK
1407	bool "Disable heap randomization"
1408	default y
1409	help
1410	  Randomizing heap placement makes heap exploits harder, but it
1411	  also breaks ancient binaries (including anything libc5 based).
1412	  This option changes the bootup default to heap randomization
1413	  disabled, and can be overridden at runtime by setting
1414	  /proc/sys/kernel/randomize_va_space to 2.
1415
1416	  On non-ancient distros (post-2000 ones) N is usually a safe choice.
1417
1418choice
1419	prompt "Choose SLAB allocator"
1420	default SLUB
1421	help
1422	   This option allows to select a slab allocator.
1423
1424config SLAB
1425	bool "SLAB"
1426	help
1427	  The regular slab allocator that is established and known to work
1428	  well in all environments. It organizes cache hot objects in
1429	  per cpu and per node queues.
1430
1431config SLUB
1432	bool "SLUB (Unqueued Allocator)"
1433	help
1434	   SLUB is a slab allocator that minimizes cache line usage
1435	   instead of managing queues of cached objects (SLAB approach).
1436	   Per cpu caching is realized using slabs of objects instead
1437	   of queues of objects. SLUB can use memory efficiently
1438	   and has enhanced diagnostics. SLUB is the default choice for
1439	   a slab allocator.
1440
1441config SLOB
1442	depends on EXPERT
1443	bool "SLOB (Simple Allocator)"
1444	help
1445	   SLOB replaces the stock allocator with a drastically simpler
1446	   allocator. SLOB is generally more space efficient but
1447	   does not perform as well on large systems.
1448
1449endchoice
1450
1451config MMAP_ALLOW_UNINITIALIZED
1452	bool "Allow mmapped anonymous memory to be uninitialized"
1453	depends on EXPERT && !MMU
1454	default n
1455	help
1456	  Normally, and according to the Linux spec, anonymous memory obtained
1457	  from mmap() has it's contents cleared before it is passed to
1458	  userspace.  Enabling this config option allows you to request that
1459	  mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1460	  providing a huge performance boost.  If this option is not enabled,
1461	  then the flag will be ignored.
1462
1463	  This is taken advantage of by uClibc's malloc(), and also by
1464	  ELF-FDPIC binfmt's brk and stack allocator.
1465
1466	  Because of the obvious security issues, this option should only be
1467	  enabled on embedded devices where you control what is run in
1468	  userspace.  Since that isn't generally a problem on no-MMU systems,
1469	  it is normally safe to say Y here.
1470
1471	  See Documentation/nommu-mmap.txt for more information.
1472
1473config PROFILING
1474	bool "Profiling support"
1475	help
1476	  Say Y here to enable the extended profiling support mechanisms used
1477	  by profilers such as OProfile.
1478
1479#
1480# Place an empty function call at each tracepoint site. Can be
1481# dynamically changed for a probe function.
1482#
1483config TRACEPOINTS
1484	bool
1485
1486source "arch/Kconfig"
1487
1488endmenu		# General setup
1489
1490config HAVE_GENERIC_DMA_COHERENT
1491	bool
1492	default n
1493
1494config SLABINFO
1495	bool
1496	depends on PROC_FS
1497	depends on SLAB || SLUB_DEBUG
1498	default y
1499
1500config RT_MUTEXES
1501	boolean
1502
1503config BASE_SMALL
1504	int
1505	default 0 if BASE_FULL
1506	default 1 if !BASE_FULL
1507
1508menuconfig MODULES
1509	bool "Enable loadable module support"
1510	help
1511	  Kernel modules are small pieces of compiled code which can
1512	  be inserted in the running kernel, rather than being
1513	  permanently built into the kernel.  You use the "modprobe"
1514	  tool to add (and sometimes remove) them.  If you say Y here,
1515	  many parts of the kernel can be built as modules (by
1516	  answering M instead of Y where indicated): this is most
1517	  useful for infrequently used options which are not required
1518	  for booting.  For more information, see the man pages for
1519	  modprobe, lsmod, modinfo, insmod and rmmod.
1520
1521	  If you say Y here, you will need to run "make
1522	  modules_install" to put the modules under /lib/modules/
1523	  where modprobe can find them (you may need to be root to do
1524	  this).
1525
1526	  If unsure, say Y.
1527
1528if MODULES
1529
1530config MODULE_FORCE_LOAD
1531	bool "Forced module loading"
1532	default n
1533	help
1534	  Allow loading of modules without version information (ie. modprobe
1535	  --force).  Forced module loading sets the 'F' (forced) taint flag and
1536	  is usually a really bad idea.
1537
1538config MODULE_UNLOAD
1539	bool "Module unloading"
1540	help
1541	  Without this option you will not be able to unload any
1542	  modules (note that some modules may not be unloadable
1543	  anyway), which makes your kernel smaller, faster
1544	  and simpler.  If unsure, say Y.
1545
1546config MODULE_FORCE_UNLOAD
1547	bool "Forced module unloading"
1548	depends on MODULE_UNLOAD && EXPERIMENTAL
1549	help
1550	  This option allows you to force a module to unload, even if the
1551	  kernel believes it is unsafe: the kernel will remove the module
1552	  without waiting for anyone to stop using it (using the -f option to
1553	  rmmod).  This is mainly for kernel developers and desperate users.
1554	  If unsure, say N.
1555
1556config MODVERSIONS
1557	bool "Module versioning support"
1558	help
1559	  Usually, you have to use modules compiled with your kernel.
1560	  Saying Y here makes it sometimes possible to use modules
1561	  compiled for different kernels, by adding enough information
1562	  to the modules to (hopefully) spot any changes which would
1563	  make them incompatible with the kernel you are running.  If
1564	  unsure, say N.
1565
1566config MODULE_SRCVERSION_ALL
1567	bool "Source checksum for all modules"
1568	help
1569	  Modules which contain a MODULE_VERSION get an extra "srcversion"
1570	  field inserted into their modinfo section, which contains a
1571    	  sum of the source files which made it.  This helps maintainers
1572	  see exactly which source was used to build a module (since
1573	  others sometimes change the module source without updating
1574	  the version).  With this option, such a "srcversion" field
1575	  will be created for all modules.  If unsure, say N.
1576
1577config MODULE_SIG
1578	bool "Module signature verification"
1579	depends on MODULES
1580	select KEYS
1581	select CRYPTO
1582	select ASYMMETRIC_KEY_TYPE
1583	select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1584	select PUBLIC_KEY_ALGO_RSA
1585	select ASN1
1586	select OID_REGISTRY
1587	select X509_CERTIFICATE_PARSER
1588	help
1589	  Check modules for valid signatures upon load: the signature
1590	  is simply appended to the module. For more information see
1591	  Documentation/module-signing.txt.
1592
1593	  !!!WARNING!!!  If you enable this option, you MUST make sure that the
1594	  module DOES NOT get stripped after being signed.  This includes the
1595	  debuginfo strip done by some packagers (such as rpmbuild) and
1596	  inclusion into an initramfs that wants the module size reduced.
1597
1598config MODULE_SIG_FORCE
1599	bool "Require modules to be validly signed"
1600	depends on MODULE_SIG
1601	help
1602	  Reject unsigned modules or signed modules for which we don't have a
1603	  key.  Without this, such modules will simply taint the kernel.
1604
1605choice
1606	prompt "Which hash algorithm should modules be signed with?"
1607	depends on MODULE_SIG
1608	help
1609	  This determines which sort of hashing algorithm will be used during
1610	  signature generation.  This algorithm _must_ be built into the kernel
1611	  directly so that signature verification can take place.  It is not
1612	  possible to load a signed module containing the algorithm to check
1613	  the signature on that module.
1614
1615config MODULE_SIG_SHA1
1616	bool "Sign modules with SHA-1"
1617	select CRYPTO_SHA1
1618
1619config MODULE_SIG_SHA224
1620	bool "Sign modules with SHA-224"
1621	select CRYPTO_SHA256
1622
1623config MODULE_SIG_SHA256
1624	bool "Sign modules with SHA-256"
1625	select CRYPTO_SHA256
1626
1627config MODULE_SIG_SHA384
1628	bool "Sign modules with SHA-384"
1629	select CRYPTO_SHA512
1630
1631config MODULE_SIG_SHA512
1632	bool "Sign modules with SHA-512"
1633	select CRYPTO_SHA512
1634
1635endchoice
1636
1637endif # MODULES
1638
1639config INIT_ALL_POSSIBLE
1640	bool
1641	help
1642	  Back when each arch used to define their own cpu_online_mask and
1643	  cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1644	  with all 1s, and others with all 0s.  When they were centralised,
1645	  it was better to provide this option than to break all the archs
1646	  and have several arch maintainers pursuing me down dark alleys.
1647
1648config STOP_MACHINE
1649	bool
1650	default y
1651	depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1652	help
1653	  Need stop_machine() primitive.
1654
1655source "block/Kconfig"
1656
1657config PREEMPT_NOTIFIERS
1658	bool
1659
1660config PADATA
1661	depends on SMP
1662	bool
1663
1664# Can be selected by architectures with broken toolchains
1665# that get confused by correct const<->read_only section
1666# mappings
1667config BROKEN_RODATA
1668	bool
1669
1670config ASN1
1671	tristate
1672	help
1673	  Build a simple ASN.1 grammar compiler that produces a bytecode output
1674	  that can be interpreted by the ASN.1 stream decoder and used to
1675	  inform it as to what tags are to be expected in a stream and what
1676	  functions to call on what tags.
1677
1678source "kernel/Kconfig.locks"
1679