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
106Math Functions in Linux
107=======================
108
109Base 2 log and power Functions
110------------------------------
111
112.. kernel-doc:: include/linux/log2.h
113   :internal:
114
115Division Functions
116------------------
117
118.. kernel-doc:: include/asm-generic/div64.h
119   :functions: do_div
120
121.. kernel-doc:: include/linux/math64.h
122   :internal:
123
124.. kernel-doc:: lib/div64.c
125   :functions: div_s64_rem div64_u64_rem div64_u64 div64_s64
126
127.. kernel-doc:: lib/gcd.c
128   :export:
129
130Sorting
131-------
132
133.. kernel-doc:: lib/sort.c
134   :export:
135
136.. kernel-doc:: lib/list_sort.c
137   :export:
138
139UUID/GUID
140---------
141
142.. kernel-doc:: lib/uuid.c
143   :export:
144
145Memory Management in Linux
146==========================
147
148The Slab Cache
149--------------
150
151.. kernel-doc:: include/linux/slab.h
152   :internal:
153
154.. kernel-doc:: mm/slab.c
155   :export:
156
157.. kernel-doc:: mm/util.c
158   :export:
159
160User Space Memory Access
161------------------------
162
163.. kernel-doc:: arch/x86/include/asm/uaccess.h
164   :internal:
165
166.. kernel-doc:: arch/x86/lib/usercopy_32.c
167   :export:
168
169More Memory Management Functions
170--------------------------------
171
172.. kernel-doc:: mm/readahead.c
173   :export:
174
175.. kernel-doc:: mm/filemap.c
176   :export:
177
178.. kernel-doc:: mm/memory.c
179   :export:
180
181.. kernel-doc:: mm/vmalloc.c
182   :export:
183
184.. kernel-doc:: mm/page_alloc.c
185   :internal:
186
187.. kernel-doc:: mm/mempool.c
188   :export:
189
190.. kernel-doc:: mm/dmapool.c
191   :export:
192
193.. kernel-doc:: mm/page-writeback.c
194   :export:
195
196.. kernel-doc:: mm/truncate.c
197   :export:
198
199Kernel IPC facilities
200=====================
201
202IPC utilities
203-------------
204
205.. kernel-doc:: ipc/util.c
206   :internal:
207
208FIFO Buffer
209===========
210
211kfifo interface
212---------------
213
214.. kernel-doc:: include/linux/kfifo.h
215   :internal:
216
217relay interface support
218=======================
219
220Relay interface support is designed to provide an efficient mechanism
221for tools and facilities to relay large amounts of data from kernel
222space to user space.
223
224relay interface
225---------------
226
227.. kernel-doc:: kernel/relay.c
228   :export:
229
230.. kernel-doc:: kernel/relay.c
231   :internal:
232
233Module Support
234==============
235
236Module Loading
237--------------
238
239.. kernel-doc:: kernel/kmod.c
240   :export:
241
242Inter Module support
243--------------------
244
245Refer to the file kernel/module.c for more information.
246
247Hardware Interfaces
248===================
249
250Interrupt Handling
251------------------
252
253.. kernel-doc:: kernel/irq/manage.c
254   :export:
255
256DMA Channels
257------------
258
259.. kernel-doc:: kernel/dma.c
260   :export:
261
262Resources Management
263--------------------
264
265.. kernel-doc:: kernel/resource.c
266   :internal:
267
268.. kernel-doc:: kernel/resource.c
269   :export:
270
271MTRR Handling
272-------------
273
274.. kernel-doc:: arch/x86/kernel/cpu/mtrr/main.c
275   :export:
276
277Security Framework
278==================
279
280.. kernel-doc:: security/security.c
281   :internal:
282
283.. kernel-doc:: security/inode.c
284   :export:
285
286Audit Interfaces
287================
288
289.. kernel-doc:: kernel/audit.c
290   :export:
291
292.. kernel-doc:: kernel/auditsc.c
293   :internal:
294
295.. kernel-doc:: kernel/auditfilter.c
296   :internal:
297
298Accounting Framework
299====================
300
301.. kernel-doc:: kernel/acct.c
302   :internal:
303
304Block Devices
305=============
306
307.. kernel-doc:: block/blk-core.c
308   :export:
309
310.. kernel-doc:: block/blk-core.c
311   :internal:
312
313.. kernel-doc:: block/blk-map.c
314   :export:
315
316.. kernel-doc:: block/blk-sysfs.c
317   :internal:
318
319.. kernel-doc:: block/blk-settings.c
320   :export:
321
322.. kernel-doc:: block/blk-exec.c
323   :export:
324
325.. kernel-doc:: block/blk-flush.c
326   :export:
327
328.. kernel-doc:: block/blk-lib.c
329   :export:
330
331.. kernel-doc:: block/blk-tag.c
332   :export:
333
334.. kernel-doc:: block/blk-tag.c
335   :internal:
336
337.. kernel-doc:: block/blk-integrity.c
338   :export:
339
340.. kernel-doc:: kernel/trace/blktrace.c
341   :internal:
342
343.. kernel-doc:: block/genhd.c
344   :internal:
345
346.. kernel-doc:: block/genhd.c
347   :export:
348
349Char devices
350============
351
352.. kernel-doc:: fs/char_dev.c
353   :export:
354
355Clock Framework
356===============
357
358The clock framework defines programming interfaces to support software
359management of the system clock tree. This framework is widely used with
360System-On-Chip (SOC) platforms to support power management and various
361devices which may need custom clock rates. Note that these "clocks"
362don't relate to timekeeping or real time clocks (RTCs), each of which
363have separate frameworks. These :c:type:`struct clk <clk>`
364instances may be used to manage for example a 96 MHz signal that is used
365to shift bits into and out of peripherals or busses, or otherwise
366trigger synchronous state machine transitions in system hardware.
367
368Power management is supported by explicit software clock gating: unused
369clocks are disabled, so the system doesn't waste power changing the
370state of transistors that aren't in active use. On some systems this may
371be backed by hardware clock gating, where clocks are gated without being
372disabled in software. Sections of chips that are powered but not clocked
373may be able to retain their last state. This low power state is often
374called a *retention mode*. This mode still incurs leakage currents,
375especially with finer circuit geometries, but for CMOS circuits power is
376mostly used by clocked state changes.
377
378Power-aware drivers only enable their clocks when the device they manage
379is in active use. Also, system sleep states often differ according to
380which clock domains are active: while a "standby" state may allow wakeup
381from several active domains, a "mem" (suspend-to-RAM) state may require
382a more wholesale shutdown of clocks derived from higher speed PLLs and
383oscillators, limiting the number of possible wakeup event sources. A
384driver's suspend method may need to be aware of system-specific clock
385constraints on the target sleep state.
386
387Some platforms support programmable clock generators. These can be used
388by external chips of various kinds, such as other CPUs, multimedia
389codecs, and devices with strict requirements for interface clocking.
390
391.. kernel-doc:: include/linux/clk.h
392   :internal:
393
394Synchronization Primitives
395==========================
396
397Read-Copy Update (RCU)
398----------------------
399
400.. kernel-doc:: include/linux/rcupdate.h
401
402.. kernel-doc:: include/linux/rcupdate_wait.h
403
404.. kernel-doc:: include/linux/rcutree.h
405
406.. kernel-doc:: kernel/rcu/tree.c
407
408.. kernel-doc:: kernel/rcu/tree_plugin.h
409
410.. kernel-doc:: kernel/rcu/tree_exp.h
411
412.. kernel-doc:: kernel/rcu/update.c
413
414.. kernel-doc:: include/linux/srcu.h
415
416.. kernel-doc:: kernel/rcu/srcutree.c
417
418.. kernel-doc:: include/linux/rculist_bl.h
419
420.. kernel-doc:: include/linux/rculist.h
421
422.. kernel-doc:: include/linux/rculist_nulls.h
423
424.. kernel-doc:: include/linux/rcu_sync.h
425
426.. kernel-doc:: kernel/rcu/sync.c
427
428