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:: include/linux/err.h
108 .. kernel-doc:: lib/sort.c
111 .. kernel-doc:: lib/list_sort.c
117 .. kernel-doc:: lib/textsearch.c
120 .. kernel-doc:: lib/textsearch.c
123 .. kernel-doc:: include/linux/textsearch.h
124 :functions: textsearch_find textsearch_next \
125 textsearch_get_pattern textsearch_get_pattern_len
127 CRC and Math Functions in Linux
128 ===============================
130 Arithmetic Overflow Checking
131 ----------------------------
133 .. kernel-doc:: include/linux/overflow.h
139 .. kernel-doc:: lib/crc4.c
142 .. kernel-doc:: lib/crc7.c
145 .. kernel-doc:: lib/crc8.c
148 .. kernel-doc:: lib/crc16.c
151 .. kernel-doc:: lib/crc32.c
153 .. kernel-doc:: lib/crc-ccitt.c
156 .. kernel-doc:: lib/crc-itu-t.c
159 Base 2 log and power Functions
160 ------------------------------
162 .. kernel-doc:: include/linux/log2.h
165 Integer power Functions
166 -----------------------
168 .. kernel-doc:: lib/math/int_pow.c
171 .. kernel-doc:: lib/math/int_sqrt.c
177 .. kernel-doc:: include/asm-generic/div64.h
180 .. kernel-doc:: include/linux/math64.h
183 .. kernel-doc:: lib/math/gcd.c
189 .. kernel-doc:: lib/uuid.c
192 Kernel IPC facilities
193 =====================
198 .. kernel-doc:: ipc/util.c
207 .. kernel-doc:: include/linux/kfifo.h
210 relay interface support
211 =======================
213 Relay interface support is designed to provide an efficient mechanism
214 for tools and facilities to relay large amounts of data from kernel
220 .. kernel-doc:: kernel/relay.c
223 .. kernel-doc:: kernel/relay.c
229 Kernel module auto-loading
230 --------------------------
232 .. kernel-doc:: kernel/module/kmod.c
238 .. kernel-doc:: kernel/module/stats.c
239 :doc: module debugging statistics overview
241 dup_failed_modules - tracks duplicate failed modules
242 ****************************************************
244 .. kernel-doc:: kernel/module/stats.c
245 :doc: dup_failed_modules - tracks duplicate failed modules
247 module statistics debugfs counters
248 **********************************
250 .. kernel-doc:: kernel/module/stats.c
251 :doc: module statistics debugfs counters
256 Refer to the files in kernel/module/ for more information.
264 .. kernel-doc:: kernel/dma.c
270 .. kernel-doc:: kernel/resource.c
273 .. kernel-doc:: kernel/resource.c
279 .. kernel-doc:: arch/x86/kernel/cpu/mtrr/mtrr.c
285 .. kernel-doc:: security/security.c
288 .. kernel-doc:: security/inode.c
294 .. kernel-doc:: kernel/audit.c
297 .. kernel-doc:: kernel/auditsc.c
300 .. kernel-doc:: kernel/auditfilter.c
306 .. kernel-doc:: kernel/acct.c
312 .. kernel-doc:: include/linux/bio.h
313 .. kernel-doc:: block/blk-core.c
316 .. kernel-doc:: block/blk-core.c
319 .. kernel-doc:: block/blk-map.c
322 .. kernel-doc:: block/blk-sysfs.c
325 .. kernel-doc:: block/blk-settings.c
328 .. kernel-doc:: block/blk-flush.c
331 .. kernel-doc:: block/blk-lib.c
334 .. kernel-doc:: block/blk-integrity.c
337 .. kernel-doc:: kernel/trace/blktrace.c
340 .. kernel-doc:: block/genhd.c
343 .. kernel-doc:: block/genhd.c
346 .. kernel-doc:: block/bdev.c
352 .. kernel-doc:: fs/char_dev.c
358 The clock framework defines programming interfaces to support software
359 management of the system clock tree. This framework is widely used with
360 System-On-Chip (SOC) platforms to support power management and various
361 devices which may need custom clock rates. Note that these "clocks"
362 don't relate to timekeeping or real time clocks (RTCs), each of which
363 have separate frameworks. These :c:type:`struct clk <clk>`
364 instances may be used to manage for example a 96 MHz signal that is used
365 to shift bits into and out of peripherals or busses, or otherwise
366 trigger synchronous state machine transitions in system hardware.
368 Power management is supported by explicit software clock gating: unused
369 clocks are disabled, so the system doesn't waste power changing the
370 state of transistors that aren't in active use. On some systems this may
371 be backed by hardware clock gating, where clocks are gated without being
372 disabled in software. Sections of chips that are powered but not clocked
373 may be able to retain their last state. This low power state is often
374 called a *retention mode*. This mode still incurs leakage currents,
375 especially with finer circuit geometries, but for CMOS circuits power is
376 mostly used by clocked state changes.
378 Power-aware drivers only enable their clocks when the device they manage
379 is in active use. Also, system sleep states often differ according to
380 which clock domains are active: while a "standby" state may allow wakeup
381 from several active domains, a "mem" (suspend-to-RAM) state may require
382 a more wholesale shutdown of clocks derived from higher speed PLLs and
383 oscillators, limiting the number of possible wakeup event sources. A
384 driver's suspend method may need to be aware of system-specific clock
385 constraints on the target sleep state.
387 Some platforms support programmable clock generators. These can be used
388 by external chips of various kinds, such as other CPUs, multimedia
389 codecs, and devices with strict requirements for interface clocking.
391 .. kernel-doc:: include/linux/clk.h
394 Synchronization Primitives
395 ==========================
397 Read-Copy Update (RCU)
398 ----------------------
400 .. kernel-doc:: include/linux/rcupdate.h
402 .. kernel-doc:: kernel/rcu/tree.c
404 .. kernel-doc:: kernel/rcu/tree_exp.h
406 .. kernel-doc:: kernel/rcu/update.c
408 .. kernel-doc:: include/linux/srcu.h
410 .. kernel-doc:: kernel/rcu/srcutree.c
412 .. kernel-doc:: include/linux/rculist_bl.h
414 .. kernel-doc:: include/linux/rculist.h
416 .. kernel-doc:: include/linux/rculist_nulls.h
418 .. kernel-doc:: include/linux/rcu_sync.h
420 .. kernel-doc:: kernel/rcu/sync.c
422 .. kernel-doc:: kernel/rcu/tasks.h
424 .. kernel-doc:: kernel/rcu/tree_stall.h
426 .. kernel-doc:: include/linux/rcupdate_trace.h
428 .. kernel-doc:: include/linux/rcupdate_wait.h
430 .. kernel-doc:: include/linux/rcuref.h
432 .. kernel-doc:: include/linux/rcutree.h