blob: f852c62b3319b514c9d9eff64994d4cf3a280ec8 [file] [log] [blame]
Harvey Harrison5638f992008-01-30 13:31:26 +01001#ifndef _ARCH_LOCAL_H
2#define _ARCH_LOCAL_H
3
4#include <linux/percpu.h>
5
6#include <asm/system.h>
7#include <asm/atomic.h>
8#include <asm/asm.h>
9
Harvey Harrison01c57fb2008-01-30 13:31:26 +010010typedef struct {
Harvey Harrison5638f992008-01-30 13:31:26 +010011 atomic_long_t a;
12} local_t;
13
14#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
15
16#define local_read(l) atomic_long_read(&(l)->a)
Harvey Harrison01c57fb2008-01-30 13:31:26 +010017#define local_set(l, i) atomic_long_set(&(l)->a, (i))
Harvey Harrison5638f992008-01-30 13:31:26 +010018
19static inline void local_inc(local_t *l)
20{
21 __asm__ __volatile__(
22 _ASM_INC "%0"
23 :"+m" (l->a.counter));
24}
25
26static inline void local_dec(local_t *l)
27{
28 __asm__ __volatile__(
29 _ASM_DEC "%0"
30 :"+m" (l->a.counter));
31}
32
33static inline void local_add(long i, local_t *l)
34{
35 __asm__ __volatile__(
36 _ASM_ADD "%1,%0"
37 :"+m" (l->a.counter)
38 :"ir" (i));
39}
40
41static inline void local_sub(long i, local_t *l)
42{
43 __asm__ __volatile__(
44 _ASM_SUB "%1,%0"
45 :"+m" (l->a.counter)
46 :"ir" (i));
47}
48
49/**
50 * local_sub_and_test - subtract value from variable and test result
51 * @i: integer value to subtract
52 * @l: pointer to type local_t
53 *
54 * Atomically subtracts @i from @l and returns
55 * true if the result is zero, or false for all
56 * other cases.
57 */
58static inline int local_sub_and_test(long i, local_t *l)
59{
60 unsigned char c;
61
62 __asm__ __volatile__(
63 _ASM_SUB "%2,%0; sete %1"
64 :"+m" (l->a.counter), "=qm" (c)
65 :"ir" (i) : "memory");
66 return c;
67}
68
69/**
70 * local_dec_and_test - decrement and test
71 * @l: pointer to type local_t
72 *
73 * Atomically decrements @l by 1 and
74 * returns true if the result is 0, or false for all other
75 * cases.
76 */
77static inline int local_dec_and_test(local_t *l)
78{
79 unsigned char c;
80
81 __asm__ __volatile__(
82 _ASM_DEC "%0; sete %1"
83 :"+m" (l->a.counter), "=qm" (c)
84 : : "memory");
85 return c != 0;
86}
87
88/**
89 * local_inc_and_test - increment and test
90 * @l: pointer to type local_t
91 *
92 * Atomically increments @l by 1
93 * and returns true if the result is zero, or false for all
94 * other cases.
95 */
96static inline int local_inc_and_test(local_t *l)
97{
98 unsigned char c;
99
100 __asm__ __volatile__(
101 _ASM_INC "%0; sete %1"
102 :"+m" (l->a.counter), "=qm" (c)
103 : : "memory");
104 return c != 0;
105}
106
107/**
108 * local_add_negative - add and test if negative
109 * @i: integer value to add
110 * @l: pointer to type local_t
111 *
112 * Atomically adds @i to @l and returns true
113 * if the result is negative, or false when
114 * result is greater than or equal to zero.
115 */
116static inline int local_add_negative(long i, local_t *l)
117{
118 unsigned char c;
119
120 __asm__ __volatile__(
121 _ASM_ADD "%2,%0; sets %1"
122 :"+m" (l->a.counter), "=qm" (c)
123 :"ir" (i) : "memory");
124 return c;
125}
126
127/**
128 * local_add_return - add and return
129 * @i: integer value to add
130 * @l: pointer to type local_t
131 *
132 * Atomically adds @i to @l and returns @i + @l
133 */
134static inline long local_add_return(long i, local_t *l)
135{
136 long __i;
137#ifdef CONFIG_M386
138 unsigned long flags;
Harvey Harrison01c57fb2008-01-30 13:31:26 +0100139 if (unlikely(boot_cpu_data.x86 <= 3))
Harvey Harrison5638f992008-01-30 13:31:26 +0100140 goto no_xadd;
Thomas Gleixner96a388d2007-10-11 11:20:03 +0200141#endif
Harvey Harrison5638f992008-01-30 13:31:26 +0100142 /* Modern 486+ processor */
143 __i = i;
144 __asm__ __volatile__(
145 _ASM_XADD "%0, %1;"
146 :"+r" (i), "+m" (l->a.counter)
147 : : "memory");
148 return i + __i;
149
150#ifdef CONFIG_M386
151no_xadd: /* Legacy 386 processor */
152 local_irq_save(flags);
153 __i = local_read(l);
154 local_set(l, i + __i);
155 local_irq_restore(flags);
156 return i + __i;
157#endif
158}
159
160static inline long local_sub_return(long i, local_t *l)
161{
Harvey Harrison01c57fb2008-01-30 13:31:26 +0100162 return local_add_return(-i, l);
Harvey Harrison5638f992008-01-30 13:31:26 +0100163}
164
Harvey Harrison01c57fb2008-01-30 13:31:26 +0100165#define local_inc_return(l) (local_add_return(1, l))
166#define local_dec_return(l) (local_sub_return(1, l))
Harvey Harrison5638f992008-01-30 13:31:26 +0100167
168#define local_cmpxchg(l, o, n) \
169 (cmpxchg_local(&((l)->a.counter), (o), (n)))
170/* Always has a lock prefix */
171#define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
172
173/**
174 * local_add_unless - add unless the number is a given value
175 * @l: pointer of type local_t
176 * @a: the amount to add to l...
177 * @u: ...unless l is equal to u.
178 *
179 * Atomically adds @a to @l, so long as it was not @u.
180 * Returns non-zero if @l was not @u, and zero otherwise.
181 */
182#define local_add_unless(l, a, u) \
183({ \
184 long c, old; \
185 c = local_read(l); \
186 for (;;) { \
187 if (unlikely(c == (u))) \
188 break; \
189 old = local_cmpxchg((l), c, c + (a)); \
190 if (likely(old == c)) \
191 break; \
192 c = old; \
193 } \
194 c != (u); \
195})
196#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
197
198/* On x86_32, these are no better than the atomic variants.
199 * On x86-64 these are better than the atomic variants on SMP kernels
200 * because they dont use a lock prefix.
201 */
202#define __local_inc(l) local_inc(l)
203#define __local_dec(l) local_dec(l)
Harvey Harrison01c57fb2008-01-30 13:31:26 +0100204#define __local_add(i, l) local_add((i), (l))
205#define __local_sub(i, l) local_sub((i), (l))
Harvey Harrison5638f992008-01-30 13:31:26 +0100206
207/* Use these for per-cpu local_t variables: on some archs they are
208 * much more efficient than these naive implementations. Note they take
209 * a variable, not an address.
210 *
211 * X86_64: This could be done better if we moved the per cpu data directly
212 * after GS.
213 */
214
215/* Need to disable preemption for the cpu local counters otherwise we could
216 still access a variable of a previous CPU in a non atomic way. */
217#define cpu_local_wrap_v(l) \
218 ({ local_t res__; \
219 preempt_disable(); \
220 res__ = (l); \
221 preempt_enable(); \
222 res__; })
223#define cpu_local_wrap(l) \
224 ({ preempt_disable(); \
225 l; \
226 preempt_enable(); }) \
227
228#define cpu_local_read(l) cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
229#define cpu_local_set(l, i) cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
230#define cpu_local_inc(l) cpu_local_wrap(local_inc(&__get_cpu_var(l)))
231#define cpu_local_dec(l) cpu_local_wrap(local_dec(&__get_cpu_var(l)))
232#define cpu_local_add(i, l) cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
233#define cpu_local_sub(i, l) cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))
234
235#define __cpu_local_inc(l) cpu_local_inc(l)
236#define __cpu_local_dec(l) cpu_local_dec(l)
237#define __cpu_local_add(i, l) cpu_local_add((i), (l))
238#define __cpu_local_sub(i, l) cpu_local_sub((i), (l))
239
240#endif /* _ARCH_LOCAL_H */