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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 | #ifndef _ASM_X86_LOCAL_H
#define _ASM_X86_LOCAL_H
#include <linux/percpu.h>
#include <asm/system.h>
#include <asm/atomic.h>
#include <asm/asm.h>
typedef struct {
atomic_long_t a;
} local_t;
#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
#define local_read(l) atomic_long_read(&(l)->a)
#define local_set(l, i) atomic_long_set(&(l)->a, (i))
static inline void local_inc(local_t *l)
{
asm volatile(_ASM_INC "%0"
: "+m" (l->a.counter));
}
static inline void local_dec(local_t *l)
{
asm volatile(_ASM_DEC "%0"
: "+m" (l->a.counter));
}
static inline void local_add(long i, local_t *l)
{
asm volatile(_ASM_ADD "%1,%0"
: "+m" (l->a.counter)
: "ir" (i));
}
static inline void local_sub(long i, local_t *l)
{
asm volatile(_ASM_SUB "%1,%0"
: "+m" (l->a.counter)
: "ir" (i));
}
/**
* local_sub_and_test - subtract value from variable and test result
* @i: integer value to subtract
* @l: pointer to type local_t
*
* Atomically subtracts @i from @l and returns
* true if the result is zero, or false for all
* other cases.
*/
static inline int local_sub_and_test(long i, local_t *l)
{
unsigned char c;
asm volatile(_ASM_SUB "%2,%0; sete %1"
: "+m" (l->a.counter), "=qm" (c)
: "ir" (i) : "memory");
return c;
}
/**
* local_dec_and_test - decrement and test
* @l: pointer to type local_t
*
* Atomically decrements @l by 1 and
* returns true if the result is 0, or false for all other
* cases.
*/
static inline int local_dec_and_test(local_t *l)
{
unsigned char c;
asm volatile(_ASM_DEC "%0; sete %1"
: "+m" (l->a.counter), "=qm" (c)
: : "memory");
return c != 0;
}
/**
* local_inc_and_test - increment and test
* @l: pointer to type local_t
*
* Atomically increments @l by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
static inline int local_inc_and_test(local_t *l)
{
unsigned char c;
asm volatile(_ASM_INC "%0; sete %1"
: "+m" (l->a.counter), "=qm" (c)
: : "memory");
return c != 0;
}
/**
* local_add_negative - add and test if negative
* @i: integer value to add
* @l: pointer to type local_t
*
* Atomically adds @i to @l and returns true
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
static inline int local_add_negative(long i, local_t *l)
{
unsigned char c;
asm volatile(_ASM_ADD "%2,%0; sets %1"
: "+m" (l->a.counter), "=qm" (c)
: "ir" (i) : "memory");
return c;
}
/**
* local_add_return - add and return
* @i: integer value to add
* @l: pointer to type local_t
*
* Atomically adds @i to @l and returns @i + @l
*/
static inline long local_add_return(long i, local_t *l)
{
long __i;
#ifdef CONFIG_M386
unsigned long flags;
if (unlikely(boot_cpu_data.x86 <= 3))
goto no_xadd;
#endif
/* Modern 486+ processor */
__i = i;
asm volatile(_ASM_XADD "%0, %1;"
: "+r" (i), "+m" (l->a.counter)
: : "memory");
return i + __i;
#ifdef CONFIG_M386
no_xadd: /* Legacy 386 processor */
local_irq_save(flags);
__i = local_read(l);
local_set(l, i + __i);
local_irq_restore(flags);
return i + __i;
#endif
}
static inline long local_sub_return(long i, local_t *l)
{
return local_add_return(-i, l);
}
#define local_inc_return(l) (local_add_return(1, l))
#define local_dec_return(l) (local_sub_return(1, l))
#define local_cmpxchg(l, o, n) \
(cmpxchg_local(&((l)->a.counter), (o), (n)))
/* Always has a lock prefix */
#define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
/**
* local_add_unless - add unless the number is a given value
* @l: pointer of type local_t
* @a: the amount to add to l...
* @u: ...unless l is equal to u.
*
* Atomically adds @a to @l, so long as it was not @u.
* Returns non-zero if @l was not @u, and zero otherwise.
*/
#define local_add_unless(l, a, u) \
({ \
long c, old; \
c = local_read((l)); \
for (;;) { \
if (unlikely(c == (u))) \
break; \
old = local_cmpxchg((l), c, c + (a)); \
if (likely(old == c)) \
break; \
c = old; \
} \
c != (u); \
})
#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
/* On x86_32, these are no better than the atomic variants.
* On x86-64 these are better than the atomic variants on SMP kernels
* because they dont use a lock prefix.
*/
#define __local_inc(l) local_inc(l)
#define __local_dec(l) local_dec(l)
#define __local_add(i, l) local_add((i), (l))
#define __local_sub(i, l) local_sub((i), (l))
#endif /* _ASM_X86_LOCAL_H */
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