1#ifndef __LINUX_SPINLOCK_H
2#define __LINUX_SPINLOCK_H
3
4/*
5 * include/linux/spinlock.h - generic spinlock/rwlock declarations
6 *
7 * here's the role of the various spinlock/rwlock related include files:
8 *
9 * on SMP builds:
10 *
11 *  asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
12 *                        initializers
13 *
14 *  linux/spinlock_types.h:
15 *                        defines the generic type and initializers
16 *
17 *  asm/spinlock.h:       contains the __raw_spin_*()/etc. lowlevel
18 *                        implementations, mostly inline assembly code
19 *
20 *   (also included on UP-debug builds:)
21 *
22 *  linux/spinlock_api_smp.h:
23 *                        contains the prototypes for the _spin_*() APIs.
24 *
25 *  linux/spinlock.h:     builds the final spin_*() APIs.
26 *
27 * on UP builds:
28 *
29 *  linux/spinlock_type_up.h:
30 *                        contains the generic, simplified UP spinlock type.
31 *                        (which is an empty structure on non-debug builds)
32 *
33 *  linux/spinlock_types.h:
34 *                        defines the generic type and initializers
35 *
36 *  linux/spinlock_up.h:
37 *                        contains the __raw_spin_*()/etc. version of UP
38 *                        builds. (which are NOPs on non-debug, non-preempt
39 *                        builds)
40 *
41 *   (included on UP-non-debug builds:)
42 *
43 *  linux/spinlock_api_up.h:
44 *                        builds the _spin_*() APIs.
45 *
46 *  linux/spinlock.h:     builds the final spin_*() APIs.
47 */
48
49#include <linux/preempt.h>
50#include <linux/linkage.h>
51#include <linux/compiler.h>
52#include <linux/thread_info.h>
53#include <linux/kernel.h>
54#include <linux/stringify.h>
55
56#include <asm/system.h>
57
58/*
59 * Must define these before including other files, inline functions need them
60 */
61#define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
62
63#define LOCK_SECTION_START(extra)               \
64        ".subsection 1\n\t"                     \
65        extra                                   \
66        ".ifndef " LOCK_SECTION_NAME "\n\t"     \
67        LOCK_SECTION_NAME ":\n\t"               \
68        ".endif\n"
69
70#define LOCK_SECTION_END                        \
71        ".previous\n\t"
72
73#define __lockfunc fastcall __attribute__((section(".spinlock.text")))
74
75/*
76 * Pull the raw_spinlock_t and raw_rwlock_t definitions:
77 */
78#include <linux/spinlock_types.h>
79
80extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
81
82/*
83 * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
84 */
85#ifdef CONFIG_SMP
86# include <asm/spinlock.h>
87#else
88# include <linux/spinlock_up.h>
89#endif
90
91#ifdef CONFIG_DEBUG_SPINLOCK
92  extern void __spin_lock_init(spinlock_t *lock, const char *name,
93			       struct lock_class_key *key);
94# define spin_lock_init(lock)					\
95do {								\
96	static struct lock_class_key __key;			\
97								\
98	__spin_lock_init((lock), #lock, &__key);		\
99} while (0)
100
101#else
102# define spin_lock_init(lock)					\
103	do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
104#endif
105
106#ifdef CONFIG_DEBUG_SPINLOCK
107  extern void __rwlock_init(rwlock_t *lock, const char *name,
108			    struct lock_class_key *key);
109# define rwlock_init(lock)					\
110do {								\
111	static struct lock_class_key __key;			\
112								\
113	__rwlock_init((lock), #lock, &__key);			\
114} while (0)
115#else
116# define rwlock_init(lock)					\
117	do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
118#endif
119
120#define spin_is_locked(lock)	__raw_spin_is_locked(&(lock)->raw_lock)
121
122/**
123 * spin_unlock_wait - wait until the spinlock gets unlocked
124 * @lock: the spinlock in question.
125 */
126#define spin_unlock_wait(lock)	__raw_spin_unlock_wait(&(lock)->raw_lock)
127
128/*
129 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
130 */
131#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
132# include <linux/spinlock_api_smp.h>
133#else
134# include <linux/spinlock_api_up.h>
135#endif
136
137#ifdef CONFIG_DEBUG_SPINLOCK
138 extern void _raw_spin_lock(spinlock_t *lock);
139#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
140 extern int _raw_spin_trylock(spinlock_t *lock);
141 extern void _raw_spin_unlock(spinlock_t *lock);
142 extern void _raw_read_lock(rwlock_t *lock);
143 extern int _raw_read_trylock(rwlock_t *lock);
144 extern void _raw_read_unlock(rwlock_t *lock);
145 extern void _raw_write_lock(rwlock_t *lock);
146 extern int _raw_write_trylock(rwlock_t *lock);
147 extern void _raw_write_unlock(rwlock_t *lock);
148#else
149# define _raw_spin_lock(lock)		__raw_spin_lock(&(lock)->raw_lock)
150# define _raw_spin_lock_flags(lock, flags) \
151		__raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
152# define _raw_spin_trylock(lock)	__raw_spin_trylock(&(lock)->raw_lock)
153# define _raw_spin_unlock(lock)		__raw_spin_unlock(&(lock)->raw_lock)
154# define _raw_read_lock(rwlock)		__raw_read_lock(&(rwlock)->raw_lock)
155# define _raw_read_trylock(rwlock)	__raw_read_trylock(&(rwlock)->raw_lock)
156# define _raw_read_unlock(rwlock)	__raw_read_unlock(&(rwlock)->raw_lock)
157# define _raw_write_lock(rwlock)	__raw_write_lock(&(rwlock)->raw_lock)
158# define _raw_write_trylock(rwlock)	__raw_write_trylock(&(rwlock)->raw_lock)
159# define _raw_write_unlock(rwlock)	__raw_write_unlock(&(rwlock)->raw_lock)
160#endif
161
162#define read_can_lock(rwlock)		__raw_read_can_lock(&(rwlock)->raw_lock)
163#define write_can_lock(rwlock)		__raw_write_can_lock(&(rwlock)->raw_lock)
164
165/*
166 * Define the various spin_lock and rw_lock methods.  Note we define these
167 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
168 * methods are defined as nops in the case they are not required.
169 */
170#define spin_trylock(lock)		__cond_lock(_spin_trylock(lock))
171#define read_trylock(lock)		__cond_lock(_read_trylock(lock))
172#define write_trylock(lock)		__cond_lock(_write_trylock(lock))
173
174#define spin_lock(lock)			_spin_lock(lock)
175
176#ifdef CONFIG_DEBUG_LOCK_ALLOC
177# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
178#else
179# define spin_lock_nested(lock, subclass) _spin_lock(lock)
180#endif
181
182#define write_lock(lock)		_write_lock(lock)
183#define read_lock(lock)			_read_lock(lock)
184
185#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
186#define spin_lock_irqsave(lock, flags)	flags = _spin_lock_irqsave(lock)
187#define read_lock_irqsave(lock, flags)	flags = _read_lock_irqsave(lock)
188#define write_lock_irqsave(lock, flags)	flags = _write_lock_irqsave(lock)
189#else
190#define spin_lock_irqsave(lock, flags)	_spin_lock_irqsave(lock, flags)
191#define read_lock_irqsave(lock, flags)	_read_lock_irqsave(lock, flags)
192#define write_lock_irqsave(lock, flags)	_write_lock_irqsave(lock, flags)
193#endif
194
195#define spin_lock_irq(lock)		_spin_lock_irq(lock)
196#define spin_lock_bh(lock)		_spin_lock_bh(lock)
197
198#define read_lock_irq(lock)		_read_lock_irq(lock)
199#define read_lock_bh(lock)		_read_lock_bh(lock)
200
201#define write_lock_irq(lock)		_write_lock_irq(lock)
202#define write_lock_bh(lock)		_write_lock_bh(lock)
203
204/*
205 * We inline the unlock functions in the nondebug case:
206 */
207#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
208	!defined(CONFIG_SMP)
209# define spin_unlock(lock)		_spin_unlock(lock)
210# define read_unlock(lock)		_read_unlock(lock)
211# define write_unlock(lock)		_write_unlock(lock)
212# define spin_unlock_irq(lock)		_spin_unlock_irq(lock)
213# define read_unlock_irq(lock)		_read_unlock_irq(lock)
214# define write_unlock_irq(lock)		_write_unlock_irq(lock)
215#else
216# define spin_unlock(lock)		__raw_spin_unlock(&(lock)->raw_lock)
217# define read_unlock(lock)		__raw_read_unlock(&(lock)->raw_lock)
218# define write_unlock(lock)		__raw_write_unlock(&(lock)->raw_lock)
219# define spin_unlock_irq(lock) \
220    do { __raw_spin_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
221# define read_unlock_irq(lock) \
222    do { __raw_read_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
223# define write_unlock_irq(lock) \
224    do { __raw_write_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
225#endif
226
227#define spin_unlock_irqrestore(lock, flags) \
228					_spin_unlock_irqrestore(lock, flags)
229#define spin_unlock_bh(lock)		_spin_unlock_bh(lock)
230
231#define read_unlock_irqrestore(lock, flags) \
232					_read_unlock_irqrestore(lock, flags)
233#define read_unlock_bh(lock)		_read_unlock_bh(lock)
234
235#define write_unlock_irqrestore(lock, flags) \
236					_write_unlock_irqrestore(lock, flags)
237#define write_unlock_bh(lock)		_write_unlock_bh(lock)
238
239#define spin_trylock_bh(lock)		__cond_lock(_spin_trylock_bh(lock))
240
241#define spin_trylock_irq(lock) \
242({ \
243	local_irq_disable(); \
244	_spin_trylock(lock) ? \
245	1 : ({ local_irq_enable(); 0;  }); \
246})
247
248#define spin_trylock_irqsave(lock, flags) \
249({ \
250	local_irq_save(flags); \
251	_spin_trylock(lock) ? \
252	1 : ({ local_irq_restore(flags); 0; }); \
253})
254
255/*
256 * Pull the atomic_t declaration:
257 * (asm-mips/atomic.h needs above definitions)
258 */
259#include <asm/atomic.h>
260/**
261 * atomic_dec_and_lock - lock on reaching reference count zero
262 * @atomic: the atomic counter
263 * @lock: the spinlock in question
264 */
265extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
266#define atomic_dec_and_lock(atomic, lock) \
267		__cond_lock(_atomic_dec_and_lock(atomic, lock))
268
269/**
270 * spin_can_lock - would spin_trylock() succeed?
271 * @lock: the spinlock in question.
272 */
273#define spin_can_lock(lock)	(!spin_is_locked(lock))
274
275#endif /* __LINUX_SPINLOCK_H */
276