1====================
2The Linux Kernel API
3====================
4
5
6List Management Functions
7=========================
8
9.. kernel-doc:: include/linux/list.h
10   :internal:
11
12Basic C Library Functions
13=========================
14
15When writing drivers, you cannot in general use routines which are from
16the C Library. Some of the functions have been found generally useful
17and they are listed below. The behaviour of these functions may vary
18slightly from those defined by ANSI, and these deviations are noted in
19the text.
20
21String Conversions
22------------------
23
24.. kernel-doc:: lib/vsprintf.c
25   :export:
26
27.. kernel-doc:: include/linux/kernel.h
28   :functions: kstrtol
29
30.. kernel-doc:: include/linux/kernel.h
31   :functions: kstrtoul
32
33.. kernel-doc:: lib/kstrtox.c
34   :export:
35
36String Manipulation
37-------------------
38
39.. kernel-doc:: lib/string.c
40   :export:
41
42Bit Operations
43--------------
44
45.. kernel-doc:: arch/x86/include/asm/bitops.h
46   :internal:
47
48Basic Kernel Library Functions
49==============================
50
51The Linux kernel provides more basic utility functions.
52
53Bitmap Operations
54-----------------
55
56.. kernel-doc:: lib/bitmap.c
57   :doc: bitmap introduction
58
59.. kernel-doc:: include/linux/bitmap.h
60   :doc: declare bitmap
61
62.. kernel-doc:: include/linux/bitmap.h
63   :doc: bitmap overview
64
65.. kernel-doc:: include/linux/bitmap.h
66   :doc: bitmap bitops
67
68.. kernel-doc:: lib/bitmap.c
69   :export:
70
71.. kernel-doc:: lib/bitmap.c
72   :internal:
73
74.. kernel-doc:: include/linux/bitmap.h
75   :internal:
76
77Command-line Parsing
78--------------------
79
80.. kernel-doc:: lib/cmdline.c
81   :export:
82
83CRC Functions
84-------------
85
86.. kernel-doc:: lib/crc4.c
87   :export:
88
89.. kernel-doc:: lib/crc7.c
90   :export:
91
92.. kernel-doc:: lib/crc8.c
93   :export:
94
95.. kernel-doc:: lib/crc16.c
96   :export:
97
98.. kernel-doc:: lib/crc32.c
99
100.. kernel-doc:: lib/crc-ccitt.c
101   :export:
102
103.. kernel-doc:: lib/crc-itu-t.c
104   :export:
105
106idr/ida Functions
107-----------------
108
109.. kernel-doc:: include/linux/idr.h
110   :doc: idr sync
111
112.. kernel-doc:: lib/idr.c
113   :doc: IDA description
114
115.. kernel-doc:: lib/idr.c
116   :export:
117
118Math Functions in Linux
119=======================
120
121Base 2 log and power Functions
122------------------------------
123
124.. kernel-doc:: include/linux/log2.h
125   :internal:
126
127Division Functions
128------------------
129
130.. kernel-doc:: include/asm-generic/div64.h
131   :functions: do_div
132
133.. kernel-doc:: include/linux/math64.h
134   :internal:
135
136.. kernel-doc:: lib/div64.c
137   :functions: div_s64_rem div64_u64_rem div64_u64 div64_s64
138
139.. kernel-doc:: lib/gcd.c
140   :export:
141
142Memory Management in Linux
143==========================
144
145The Slab Cache
146--------------
147
148.. kernel-doc:: include/linux/slab.h
149   :internal:
150
151.. kernel-doc:: mm/slab.c
152   :export:
153
154.. kernel-doc:: mm/util.c
155   :export:
156
157User Space Memory Access
158------------------------
159
160.. kernel-doc:: arch/x86/include/asm/uaccess.h
161   :internal:
162
163.. kernel-doc:: arch/x86/lib/usercopy_32.c
164   :export:
165
166More Memory Management Functions
167--------------------------------
168
169.. kernel-doc:: mm/readahead.c
170   :export:
171
172.. kernel-doc:: mm/filemap.c
173   :export:
174
175.. kernel-doc:: mm/memory.c
176   :export:
177
178.. kernel-doc:: mm/vmalloc.c
179   :export:
180
181.. kernel-doc:: mm/page_alloc.c
182   :internal:
183
184.. kernel-doc:: mm/mempool.c
185   :export:
186
187.. kernel-doc:: mm/dmapool.c
188   :export:
189
190.. kernel-doc:: mm/page-writeback.c
191   :export:
192
193.. kernel-doc:: mm/truncate.c
194   :export:
195
196Kernel IPC facilities
197=====================
198
199IPC utilities
200-------------
201
202.. kernel-doc:: ipc/util.c
203   :internal:
204
205FIFO Buffer
206===========
207
208kfifo interface
209---------------
210
211.. kernel-doc:: include/linux/kfifo.h
212   :internal:
213
214relay interface support
215=======================
216
217Relay interface support is designed to provide an efficient mechanism
218for tools and facilities to relay large amounts of data from kernel
219space to user space.
220
221relay interface
222---------------
223
224.. kernel-doc:: kernel/relay.c
225   :export:
226
227.. kernel-doc:: kernel/relay.c
228   :internal:
229
230Module Support
231==============
232
233Module Loading
234--------------
235
236.. kernel-doc:: kernel/kmod.c
237   :export:
238
239Inter Module support
240--------------------
241
242Refer to the file kernel/module.c for more information.
243
244Hardware Interfaces
245===================
246
247Interrupt Handling
248------------------
249
250.. kernel-doc:: kernel/irq/manage.c
251   :export:
252
253DMA Channels
254------------
255
256.. kernel-doc:: kernel/dma.c
257   :export:
258
259Resources Management
260--------------------
261
262.. kernel-doc:: kernel/resource.c
263   :internal:
264
265.. kernel-doc:: kernel/resource.c
266   :export:
267
268MTRR Handling
269-------------
270
271.. kernel-doc:: arch/x86/kernel/cpu/mtrr/main.c
272   :export:
273
274Security Framework
275==================
276
277.. kernel-doc:: security/security.c
278   :internal:
279
280.. kernel-doc:: security/inode.c
281   :export:
282
283Audit Interfaces
284================
285
286.. kernel-doc:: kernel/audit.c
287   :export:
288
289.. kernel-doc:: kernel/auditsc.c
290   :internal:
291
292.. kernel-doc:: kernel/auditfilter.c
293   :internal:
294
295Accounting Framework
296====================
297
298.. kernel-doc:: kernel/acct.c
299   :internal:
300
301Block Devices
302=============
303
304.. kernel-doc:: block/blk-core.c
305   :export:
306
307.. kernel-doc:: block/blk-core.c
308   :internal:
309
310.. kernel-doc:: block/blk-map.c
311   :export:
312
313.. kernel-doc:: block/blk-sysfs.c
314   :internal:
315
316.. kernel-doc:: block/blk-settings.c
317   :export:
318
319.. kernel-doc:: block/blk-exec.c
320   :export:
321
322.. kernel-doc:: block/blk-flush.c
323   :export:
324
325.. kernel-doc:: block/blk-lib.c
326   :export:
327
328.. kernel-doc:: block/blk-tag.c
329   :export:
330
331.. kernel-doc:: block/blk-tag.c
332   :internal:
333
334.. kernel-doc:: block/blk-integrity.c
335   :export:
336
337.. kernel-doc:: kernel/trace/blktrace.c
338   :internal:
339
340.. kernel-doc:: block/genhd.c
341   :internal:
342
343.. kernel-doc:: block/genhd.c
344   :export:
345
346Char devices
347============
348
349.. kernel-doc:: fs/char_dev.c
350   :export:
351
352Clock Framework
353===============
354
355The clock framework defines programming interfaces to support software
356management of the system clock tree. This framework is widely used with
357System-On-Chip (SOC) platforms to support power management and various
358devices which may need custom clock rates. Note that these "clocks"
359don't relate to timekeeping or real time clocks (RTCs), each of which
360have separate frameworks. These :c:type:`struct clk <clk>`
361instances may be used to manage for example a 96 MHz signal that is used
362to shift bits into and out of peripherals or busses, or otherwise
363trigger synchronous state machine transitions in system hardware.
364
365Power management is supported by explicit software clock gating: unused
366clocks are disabled, so the system doesn't waste power changing the
367state of transistors that aren't in active use. On some systems this may
368be backed by hardware clock gating, where clocks are gated without being
369disabled in software. Sections of chips that are powered but not clocked
370may be able to retain their last state. This low power state is often
371called a *retention mode*. This mode still incurs leakage currents,
372especially with finer circuit geometries, but for CMOS circuits power is
373mostly used by clocked state changes.
374
375Power-aware drivers only enable their clocks when the device they manage
376is in active use. Also, system sleep states often differ according to
377which clock domains are active: while a "standby" state may allow wakeup
378from several active domains, a "mem" (suspend-to-RAM) state may require
379a more wholesale shutdown of clocks derived from higher speed PLLs and
380oscillators, limiting the number of possible wakeup event sources. A
381driver's suspend method may need to be aware of system-specific clock
382constraints on the target sleep state.
383
384Some platforms support programmable clock generators. These can be used
385by external chips of various kinds, such as other CPUs, multimedia
386codecs, and devices with strict requirements for interface clocking.
387
388.. kernel-doc:: include/linux/clk.h
389   :internal:
390
391Synchronization Primitives
392==========================
393
394Read-Copy Update (RCU)
395----------------------
396
397.. kernel-doc:: include/linux/rcupdate.h
398
399.. kernel-doc:: include/linux/rcupdate_wait.h
400
401.. kernel-doc:: include/linux/rcutree.h
402
403.. kernel-doc:: kernel/rcu/tree.c
404
405.. kernel-doc:: kernel/rcu/tree_plugin.h
406
407.. kernel-doc:: kernel/rcu/tree_exp.h
408
409.. kernel-doc:: kernel/rcu/update.c
410
411.. kernel-doc:: include/linux/srcu.h
412
413.. kernel-doc:: kernel/rcu/srcutree.c
414
415.. kernel-doc:: include/linux/rculist_bl.h
416
417.. kernel-doc:: include/linux/rculist.h
418
419.. kernel-doc:: include/linux/rculist_nulls.h
420
421.. kernel-doc:: include/linux/rcu_sync.h
422
423.. kernel-doc:: kernel/rcu/sync.c
424
425