Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _ASM_X86_LOCAL_H
       3             : #define _ASM_X86_LOCAL_H
       4             : 
       5             : #include <linux/percpu.h>
       6             : 
       7             : #include <linux/atomic.h>
       8             : #include <asm/asm.h>
       9             : 
      10             : typedef struct {
      11             :         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)
      17             : #define local_set(l, i) atomic_long_set(&(l)->a, (i))
      18             : 
      19             : static inline void local_inc(local_t *l)
      20             : {
      21           0 :         asm volatile(_ASM_INC "%0"
      22             :                      : "+m" (l->a.counter));
      23             : }
      24             : 
      25             : static inline void local_dec(local_t *l)
      26             : {
      27           0 :         asm volatile(_ASM_DEC "%0"
      28             :                      : "+m" (l->a.counter));
      29             : }
      30             : 
      31             : static inline void local_add(long i, local_t *l)
      32             : {
      33             :         asm volatile(_ASM_ADD "%1,%0"
      34             :                      : "+m" (l->a.counter)
      35             :                      : "ir" (i));
      36             : }
      37             : 
      38             : static inline void local_sub(long i, local_t *l)
      39             : {
      40             :         asm volatile(_ASM_SUB "%1,%0"
      41             :                      : "+m" (l->a.counter)
      42             :                      : "ir" (i));
      43             : }
      44             : 
      45             : /**
      46             :  * local_sub_and_test - subtract value from variable and test result
      47             :  * @i: integer value to subtract
      48             :  * @l: pointer to type local_t
      49             :  *
      50             :  * Atomically subtracts @i from @l and returns
      51             :  * true if the result is zero, or false for all
      52             :  * other cases.
      53             :  */
      54             : static inline bool local_sub_and_test(long i, local_t *l)
      55             : {
      56             :         return GEN_BINARY_RMWcc(_ASM_SUB, l->a.counter, e, "er", i);
      57             : }
      58             : 
      59             : /**
      60             :  * local_dec_and_test - decrement and test
      61             :  * @l: pointer to type local_t
      62             :  *
      63             :  * Atomically decrements @l by 1 and
      64             :  * returns true if the result is 0, or false for all other
      65             :  * cases.
      66             :  */
      67             : static inline bool local_dec_and_test(local_t *l)
      68             : {
      69             :         return GEN_UNARY_RMWcc(_ASM_DEC, l->a.counter, e);
      70             : }
      71             : 
      72             : /**
      73             :  * local_inc_and_test - increment and test
      74             :  * @l: pointer to type local_t
      75             :  *
      76             :  * Atomically increments @l by 1
      77             :  * and returns true if the result is zero, or false for all
      78             :  * other cases.
      79             :  */
      80             : static inline bool local_inc_and_test(local_t *l)
      81             : {
      82             :         return GEN_UNARY_RMWcc(_ASM_INC, l->a.counter, e);
      83             : }
      84             : 
      85             : /**
      86             :  * local_add_negative - add and test if negative
      87             :  * @i: integer value to add
      88             :  * @l: pointer to type local_t
      89             :  *
      90             :  * Atomically adds @i to @l and returns true
      91             :  * if the result is negative, or false when
      92             :  * result is greater than or equal to zero.
      93             :  */
      94             : static inline bool local_add_negative(long i, local_t *l)
      95             : {
      96             :         return GEN_BINARY_RMWcc(_ASM_ADD, l->a.counter, s, "er", i);
      97             : }
      98             : 
      99             : /**
     100             :  * local_add_return - add and return
     101             :  * @i: integer value to add
     102             :  * @l: pointer to type local_t
     103             :  *
     104             :  * Atomically adds @i to @l and returns @i + @l
     105             :  */
     106             : static inline long local_add_return(long i, local_t *l)
     107             : {
     108             :         long __i = i;
     109             :         asm volatile(_ASM_XADD "%0, %1;"
     110             :                      : "+r" (i), "+m" (l->a.counter)
     111             :                      : : "memory");
     112             :         return i + __i;
     113             : }
     114             : 
     115             : static inline long local_sub_return(long i, local_t *l)
     116             : {
     117             :         return local_add_return(-i, l);
     118             : }
     119             : 
     120             : #define local_inc_return(l)  (local_add_return(1, l))
     121             : #define local_dec_return(l)  (local_sub_return(1, l))
     122             : 
     123             : #define local_cmpxchg(l, o, n) \
     124             :         (cmpxchg_local(&((l)->a.counter), (o), (n)))
     125             : /* Always has a lock prefix */
     126             : #define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
     127             : 
     128             : /**
     129             :  * local_add_unless - add unless the number is a given value
     130             :  * @l: pointer of type local_t
     131             :  * @a: the amount to add to l...
     132             :  * @u: ...unless l is equal to u.
     133             :  *
     134             :  * Atomically adds @a to @l, so long as it was not @u.
     135             :  * Returns non-zero if @l was not @u, and zero otherwise.
     136             :  */
     137             : #define local_add_unless(l, a, u)                               \
     138             : ({                                                              \
     139             :         long c, old;                                            \
     140             :         c = local_read((l));                                    \
     141             :         for (;;) {                                              \
     142             :                 if (unlikely(c == (u)))                         \
     143             :                         break;                                  \
     144             :                 old = local_cmpxchg((l), c, c + (a));           \
     145             :                 if (likely(old == c))                           \
     146             :                         break;                                  \
     147             :                 c = old;                                        \
     148             :         }                                                       \
     149             :         c != (u);                                               \
     150             : })
     151             : #define local_inc_not_zero(l) local_add_unless((l), 1, 0)
     152             : 
     153             : /* On x86_32, these are no better than the atomic variants.
     154             :  * On x86-64 these are better than the atomic variants on SMP kernels
     155             :  * because they dont use a lock prefix.
     156             :  */
     157             : #define __local_inc(l)          local_inc(l)
     158             : #define __local_dec(l)          local_dec(l)
     159             : #define __local_add(i, l)       local_add((i), (l))
     160             : #define __local_sub(i, l)       local_sub((i), (l))
     161             : 
     162             : #endif /* _ASM_X86_LOCAL_H */