6 List Management Functions
7 =========================
9 .. kernel-doc:: include/linux/list.h
12 Basic C Library Functions
13 =========================
15 When writing drivers, you cannot in general use routines which are from
16 the C Library. Some of the functions have been found generally useful
17 and they are listed below. The behaviour of these functions may vary
18 slightly from those defined by ANSI, and these deviations are noted in
24 .. kernel-doc:: lib/vsprintf.c
27 .. kernel-doc:: include/linux/kstrtox.h
28 :functions: kstrtol kstrtoul
30 .. kernel-doc:: lib/kstrtox.c
33 .. kernel-doc:: lib/string_helpers.c
39 .. kernel-doc:: include/linux/fortify-string.h
42 .. kernel-doc:: lib/string.c
45 .. kernel-doc:: include/linux/string.h
48 .. kernel-doc:: mm/util.c
49 :functions: kstrdup kstrdup_const kstrndup kmemdup kmemdup_nul memdup_user
50 vmemdup_user strndup_user memdup_user_nul
52 Basic Kernel Library Functions
53 ==============================
55 The Linux kernel provides more basic utility functions.
60 .. kernel-doc:: include/asm-generic/bitops/instrumented-atomic.h
63 .. kernel-doc:: include/asm-generic/bitops/instrumented-non-atomic.h
66 .. kernel-doc:: include/asm-generic/bitops/instrumented-lock.h
72 .. kernel-doc:: lib/bitmap.c
73 :doc: bitmap introduction
75 .. kernel-doc:: include/linux/bitmap.h
78 .. kernel-doc:: include/linux/bitmap.h
81 .. kernel-doc:: include/linux/bitmap.h
84 .. kernel-doc:: lib/bitmap.c
87 .. kernel-doc:: lib/bitmap.c
90 .. kernel-doc:: include/linux/bitmap.h
96 .. kernel-doc:: lib/cmdline.c
102 .. kernel-doc:: lib/sort.c
105 .. kernel-doc:: lib/list_sort.c
111 .. kernel-doc:: lib/textsearch.c
114 .. kernel-doc:: lib/textsearch.c
117 .. kernel-doc:: include/linux/textsearch.h
118 :functions: textsearch_find textsearch_next \
119 textsearch_get_pattern textsearch_get_pattern_len
121 CRC and Math Functions in Linux
122 ===============================
124 Arithmetic Overflow Checking
125 ----------------------------
127 .. kernel-doc:: include/linux/overflow.h
133 .. kernel-doc:: lib/crc4.c
136 .. kernel-doc:: lib/crc7.c
139 .. kernel-doc:: lib/crc8.c
142 .. kernel-doc:: lib/crc16.c
145 .. kernel-doc:: lib/crc32.c
147 .. kernel-doc:: lib/crc-ccitt.c
150 .. kernel-doc:: lib/crc-itu-t.c
153 Base 2 log and power Functions
154 ------------------------------
156 .. kernel-doc:: include/linux/log2.h
159 Integer power Functions
160 -----------------------
162 .. kernel-doc:: lib/math/int_pow.c
165 .. kernel-doc:: lib/math/int_sqrt.c
171 .. kernel-doc:: include/asm-generic/div64.h
174 .. kernel-doc:: include/linux/math64.h
177 .. kernel-doc:: lib/math/gcd.c
183 .. kernel-doc:: lib/uuid.c
186 Kernel IPC facilities
187 =====================
192 .. kernel-doc:: ipc/util.c
201 .. kernel-doc:: include/linux/kfifo.h
204 relay interface support
205 =======================
207 Relay interface support is designed to provide an efficient mechanism
208 for tools and facilities to relay large amounts of data from kernel
214 .. kernel-doc:: kernel/relay.c
217 .. kernel-doc:: kernel/relay.c
223 Kernel module auto-loading
224 --------------------------
226 .. kernel-doc:: kernel/module/kmod.c
232 .. kernel-doc:: kernel/module/stats.c
233 :doc: module debugging statistics overview
235 dup_failed_modules - tracks duplicate failed modules
236 ****************************************************
238 .. kernel-doc:: kernel/module/stats.c
239 :doc: dup_failed_modules - tracks duplicate failed modules
241 module statistics debugfs counters
242 **********************************
244 .. kernel-doc:: kernel/module/stats.c
245 :doc: module statistics debugfs counters
250 Refer to the files in kernel/module/ for more information.
258 .. kernel-doc:: kernel/dma.c
264 .. kernel-doc:: kernel/resource.c
267 .. kernel-doc:: kernel/resource.c
273 .. kernel-doc:: arch/x86/kernel/cpu/mtrr/mtrr.c
279 .. kernel-doc:: security/security.c
282 .. kernel-doc:: security/inode.c
288 .. kernel-doc:: kernel/audit.c
291 .. kernel-doc:: kernel/auditsc.c
294 .. kernel-doc:: kernel/auditfilter.c
300 .. kernel-doc:: kernel/acct.c
306 .. kernel-doc:: include/linux/bio.h
307 .. kernel-doc:: block/blk-core.c
310 .. kernel-doc:: block/blk-core.c
313 .. kernel-doc:: block/blk-map.c
316 .. kernel-doc:: block/blk-sysfs.c
319 .. kernel-doc:: block/blk-settings.c
322 .. kernel-doc:: block/blk-flush.c
325 .. kernel-doc:: block/blk-lib.c
328 .. kernel-doc:: block/blk-integrity.c
331 .. kernel-doc:: kernel/trace/blktrace.c
334 .. kernel-doc:: block/genhd.c
337 .. kernel-doc:: block/genhd.c
340 .. kernel-doc:: block/bdev.c
346 .. kernel-doc:: fs/char_dev.c
352 The clock framework defines programming interfaces to support software
353 management of the system clock tree. This framework is widely used with
354 System-On-Chip (SOC) platforms to support power management and various
355 devices which may need custom clock rates. Note that these "clocks"
356 don't relate to timekeeping or real time clocks (RTCs), each of which
357 have separate frameworks. These :c:type:`struct clk <clk>`
358 instances may be used to manage for example a 96 MHz signal that is used
359 to shift bits into and out of peripherals or busses, or otherwise
360 trigger synchronous state machine transitions in system hardware.
362 Power management is supported by explicit software clock gating: unused
363 clocks are disabled, so the system doesn't waste power changing the
364 state of transistors that aren't in active use. On some systems this may
365 be backed by hardware clock gating, where clocks are gated without being
366 disabled in software. Sections of chips that are powered but not clocked
367 may be able to retain their last state. This low power state is often
368 called a *retention mode*. This mode still incurs leakage currents,
369 especially with finer circuit geometries, but for CMOS circuits power is
370 mostly used by clocked state changes.
372 Power-aware drivers only enable their clocks when the device they manage
373 is in active use. Also, system sleep states often differ according to
374 which clock domains are active: while a "standby" state may allow wakeup
375 from several active domains, a "mem" (suspend-to-RAM) state may require
376 a more wholesale shutdown of clocks derived from higher speed PLLs and
377 oscillators, limiting the number of possible wakeup event sources. A
378 driver's suspend method may need to be aware of system-specific clock
379 constraints on the target sleep state.
381 Some platforms support programmable clock generators. These can be used
382 by external chips of various kinds, such as other CPUs, multimedia
383 codecs, and devices with strict requirements for interface clocking.
385 .. kernel-doc:: include/linux/clk.h
388 Synchronization Primitives
389 ==========================
391 Read-Copy Update (RCU)
392 ----------------------
394 .. kernel-doc:: include/linux/rcupdate.h
396 .. kernel-doc:: kernel/rcu/tree.c
398 .. kernel-doc:: kernel/rcu/tree_exp.h
400 .. kernel-doc:: kernel/rcu/update.c
402 .. kernel-doc:: include/linux/srcu.h
404 .. kernel-doc:: kernel/rcu/srcutree.c
406 .. kernel-doc:: include/linux/rculist_bl.h
408 .. kernel-doc:: include/linux/rculist.h
410 .. kernel-doc:: include/linux/rculist_nulls.h
412 .. kernel-doc:: include/linux/rcu_sync.h
414 .. kernel-doc:: kernel/rcu/sync.c