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/kernel.h
30 .. kernel-doc:: include/linux/kernel.h
33 .. kernel-doc:: lib/kstrtox.c
39 .. kernel-doc:: lib/string.c
45 .. kernel-doc:: arch/x86/include/asm/bitops.h
48 Basic Kernel Library Functions
49 ==============================
51 The Linux kernel provides more basic utility functions.
56 .. kernel-doc:: lib/bitmap.c
57 :doc: bitmap introduction
59 .. kernel-doc:: include/linux/bitmap.h
62 .. kernel-doc:: include/linux/bitmap.h
65 .. kernel-doc:: include/linux/bitmap.h
68 .. kernel-doc:: lib/bitmap.c
71 .. kernel-doc:: lib/bitmap.c
74 .. kernel-doc:: include/linux/bitmap.h
80 .. kernel-doc:: lib/cmdline.c
86 .. kernel-doc:: lib/crc4.c
89 .. kernel-doc:: lib/crc7.c
92 .. kernel-doc:: lib/crc8.c
95 .. kernel-doc:: lib/crc16.c
98 .. kernel-doc:: lib/crc32.c
100 .. kernel-doc:: lib/crc-ccitt.c
103 .. kernel-doc:: lib/crc-itu-t.c
109 .. kernel-doc:: include/linux/idr.h
112 .. kernel-doc:: lib/idr.c
113 :doc: IDA description
115 .. kernel-doc:: lib/idr.c
118 Math Functions in Linux
119 =======================
121 Base 2 log and power Functions
122 ------------------------------
124 .. kernel-doc:: include/linux/log2.h
130 .. kernel-doc:: include/asm-generic/div64.h
133 .. kernel-doc:: include/linux/math64.h
136 .. kernel-doc:: lib/div64.c
137 :functions: div_s64_rem div64_u64_rem div64_u64 div64_s64
139 .. kernel-doc:: lib/gcd.c
145 .. kernel-doc:: lib/sort.c
148 .. kernel-doc:: lib/list_sort.c
154 .. kernel-doc:: lib/uuid.c
157 Memory Management in Linux
158 ==========================
163 .. kernel-doc:: include/linux/slab.h
166 .. kernel-doc:: mm/slab.c
169 .. kernel-doc:: mm/util.c
172 User Space Memory Access
173 ------------------------
175 .. kernel-doc:: arch/x86/include/asm/uaccess.h
178 .. kernel-doc:: arch/x86/lib/usercopy_32.c
181 More Memory Management Functions
182 --------------------------------
184 .. kernel-doc:: mm/readahead.c
187 .. kernel-doc:: mm/filemap.c
190 .. kernel-doc:: mm/memory.c
193 .. kernel-doc:: mm/vmalloc.c
196 .. kernel-doc:: mm/page_alloc.c
199 .. kernel-doc:: mm/mempool.c
202 .. kernel-doc:: mm/dmapool.c
205 .. kernel-doc:: mm/page-writeback.c
208 .. kernel-doc:: mm/truncate.c
211 Kernel IPC facilities
212 =====================
217 .. kernel-doc:: ipc/util.c
226 .. kernel-doc:: include/linux/kfifo.h
229 relay interface support
230 =======================
232 Relay interface support is designed to provide an efficient mechanism
233 for tools and facilities to relay large amounts of data from kernel
239 .. kernel-doc:: kernel/relay.c
242 .. kernel-doc:: kernel/relay.c
251 .. kernel-doc:: kernel/kmod.c
257 Refer to the file kernel/module.c for more information.
265 .. kernel-doc:: kernel/irq/manage.c
271 .. kernel-doc:: kernel/dma.c
277 .. kernel-doc:: kernel/resource.c
280 .. kernel-doc:: kernel/resource.c
286 .. kernel-doc:: arch/x86/kernel/cpu/mtrr/main.c
292 .. kernel-doc:: security/security.c
295 .. kernel-doc:: security/inode.c
301 .. kernel-doc:: kernel/audit.c
304 .. kernel-doc:: kernel/auditsc.c
307 .. kernel-doc:: kernel/auditfilter.c
313 .. kernel-doc:: kernel/acct.c
319 .. kernel-doc:: block/blk-core.c
322 .. kernel-doc:: block/blk-core.c
325 .. kernel-doc:: block/blk-map.c
328 .. kernel-doc:: block/blk-sysfs.c
331 .. kernel-doc:: block/blk-settings.c
334 .. kernel-doc:: block/blk-exec.c
337 .. kernel-doc:: block/blk-flush.c
340 .. kernel-doc:: block/blk-lib.c
343 .. kernel-doc:: block/blk-tag.c
346 .. kernel-doc:: block/blk-tag.c
349 .. kernel-doc:: block/blk-integrity.c
352 .. kernel-doc:: kernel/trace/blktrace.c
355 .. kernel-doc:: block/genhd.c
358 .. kernel-doc:: block/genhd.c
364 .. kernel-doc:: fs/char_dev.c
370 The clock framework defines programming interfaces to support software
371 management of the system clock tree. This framework is widely used with
372 System-On-Chip (SOC) platforms to support power management and various
373 devices which may need custom clock rates. Note that these "clocks"
374 don't relate to timekeeping or real time clocks (RTCs), each of which
375 have separate frameworks. These :c:type:`struct clk <clk>`
376 instances may be used to manage for example a 96 MHz signal that is used
377 to shift bits into and out of peripherals or busses, or otherwise
378 trigger synchronous state machine transitions in system hardware.
380 Power management is supported by explicit software clock gating: unused
381 clocks are disabled, so the system doesn't waste power changing the
382 state of transistors that aren't in active use. On some systems this may
383 be backed by hardware clock gating, where clocks are gated without being
384 disabled in software. Sections of chips that are powered but not clocked
385 may be able to retain their last state. This low power state is often
386 called a *retention mode*. This mode still incurs leakage currents,
387 especially with finer circuit geometries, but for CMOS circuits power is
388 mostly used by clocked state changes.
390 Power-aware drivers only enable their clocks when the device they manage
391 is in active use. Also, system sleep states often differ according to
392 which clock domains are active: while a "standby" state may allow wakeup
393 from several active domains, a "mem" (suspend-to-RAM) state may require
394 a more wholesale shutdown of clocks derived from higher speed PLLs and
395 oscillators, limiting the number of possible wakeup event sources. A
396 driver's suspend method may need to be aware of system-specific clock
397 constraints on the target sleep state.
399 Some platforms support programmable clock generators. These can be used
400 by external chips of various kinds, such as other CPUs, multimedia
401 codecs, and devices with strict requirements for interface clocking.
403 .. kernel-doc:: include/linux/clk.h
406 Synchronization Primitives
407 ==========================
409 Read-Copy Update (RCU)
410 ----------------------
412 .. kernel-doc:: include/linux/rcupdate.h
414 .. kernel-doc:: include/linux/rcupdate_wait.h
416 .. kernel-doc:: include/linux/rcutree.h
418 .. kernel-doc:: kernel/rcu/tree.c
420 .. kernel-doc:: kernel/rcu/tree_plugin.h
422 .. kernel-doc:: kernel/rcu/tree_exp.h
424 .. kernel-doc:: kernel/rcu/update.c
426 .. kernel-doc:: include/linux/srcu.h
428 .. kernel-doc:: kernel/rcu/srcutree.c
430 .. kernel-doc:: include/linux/rculist_bl.h
432 .. kernel-doc:: include/linux/rculist.h
434 .. kernel-doc:: include/linux/rculist_nulls.h
436 .. kernel-doc:: include/linux/rcu_sync.h
438 .. kernel-doc:: kernel/rcu/sync.c