arch/hexagon/include/asm/atomic.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Atomic operations for the Hexagon architecture
   4  *
   5  * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
   6  */
   7
   8 #ifndef _ASM_ATOMIC_H
   9 #define _ASM_ATOMIC_H
  10
  11 #include <linux/types.h>
  12 #include <asm/cmpxchg.h>
  13 #include <asm/barrier.h>
  14
  15 #define ATOMIC_INIT(i)          { (i) }
  16
  17 /*  Normal writes in our arch don't clear lock reservations  */
  18
  19 static inline void atomic_set(atomic_t *v, int new)
  20 {
  21         asm volatile(
  22                 "1:     r6 = memw_locked(%0);\n"
  23                 "       memw_locked(%0,p0) = %1;\n"
  24                 "       if (!P0) jump 1b;\n"
  25                 :
  26                 : "r" (&v->counter), "r" (new)
  27                 : "memory", "p0", "r6"
  28         );
  29 }
  30
  31 #define atomic_set_release(v, i)        atomic_set((v), (i))
  32
  33 /**
  34  * atomic_read - reads a word, atomically
  35  * @v: pointer to atomic value
  36  *
  37  * Assumes all word reads on our architecture are atomic.
  38  */
  39 #define atomic_read(v)          READ_ONCE((v)->counter)
  40
  41 /**
  42  * atomic_xchg - atomic
  43  * @v: pointer to memory to change
  44  * @new: new value (technically passed in a register -- see xchg)
  45  */
  46 #define atomic_xchg(v, new)     (xchg(&((v)->counter), (new)))
  47
  48
  49 /**
  50  * atomic_cmpxchg - atomic compare-and-exchange values
  51  * @v: pointer to value to change
  52  * @old:  desired old value to match
  53  * @new:  new value to put in
  54  *
  55  * Parameters are then pointer, value-in-register, value-in-register,
  56  * and the output is the old value.
  57  *
  58  * Apparently this is complicated for archs that don't support
  59  * the memw_locked like we do (or it's broken or whatever).
  60  *
  61  * Kind of the lynchpin of the rest of the generically defined routines.
  62  * Remember V2 had that bug with dotnew predicate set by memw_locked.
  63  *
  64  * "old" is "expected" old val, __oldval is actual old value
  65  */
  66 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
  67 {
  68         int __oldval;
  69
  70         asm volatile(
  71                 "1:     %0 = memw_locked(%1);\n"
  72                 "       { P0 = cmp.eq(%0,%2);\n"
  73                 "         if (!P0.new) jump:nt 2f; }\n"
  74                 "       memw_locked(%1,P0) = %3;\n"
  75                 "       if (!P0) jump 1b;\n"
  76                 "2:\n"
  77                 : "=&r" (__oldval)
  78                 : "r" (&v->counter), "r" (old), "r" (new)
  79                 : "memory", "p0"
  80         );
  81
  82         return __oldval;
  83 }
  84
  85 #define ATOMIC_OP(op)                                                   \
  86 static inline void atomic_##op(int i, atomic_t *v)                      \
  87 {                                                                       \
  88         int output;                                                     \
  89                                                                         \
  90         __asm__ __volatile__ (                                          \
  91                 "1:     %0 = memw_locked(%1);\n"                        \
  92                 "       %0 = "#op "(%0,%2);\n"                          \
  93                 "       memw_locked(%1,P3)=%0;\n"                       \
  94                 "       if !P3 jump 1b;\n"                              \
  95                 : "=&r" (output)                                        \
  96                 : "r" (&v->counter), "r" (i)                            \
  97                 : "memory", "p3"                                        \
  98         );                                                              \
  99 }                                                                       \
 100
 101 #define ATOMIC_OP_RETURN(op)                                            \
 102 static inline int atomic_##op##_return(int i, atomic_t *v)              \
 103 {                                                                       \
 104         int output;                                                     \
 105                                                                         \
 106         __asm__ __volatile__ (                                          \
 107                 "1:     %0 = memw_locked(%1);\n"                        \
 108                 "       %0 = "#op "(%0,%2);\n"                          \
 109                 "       memw_locked(%1,P3)=%0;\n"                       \
 110                 "       if !P3 jump 1b;\n"                              \
 111                 : "=&r" (output)                                        \
 112                 : "r" (&v->counter), "r" (i)                            \
 113                 : "memory", "p3"                                        \
 114         );                                                              \
 115         return output;                                                  \
 116 }
 117
 118 #define ATOMIC_FETCH_OP(op)                                             \
 119 static inline int atomic_fetch_##op(int i, atomic_t *v)                 \
 120 {                                                                       \
 121         int output, val;                                                \
 122                                                                         \
 123         __asm__ __volatile__ (                                          \
 124                 "1:     %0 = memw_locked(%2);\n"                        \
 125                 "       %1 = "#op "(%0,%3);\n"                          \
 126                 "       memw_locked(%2,P3)=%1;\n"                       \
 127                 "       if !P3 jump 1b;\n"                              \
 128                 : "=&r" (output), "=&r" (val)                           \
 129                 : "r" (&v->counter), "r" (i)                            \
 130                 : "memory", "p3"                                        \
 131         );                                                              \
 132         return output;                                                  \
 133 }
 134
 135 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
 136
 137 ATOMIC_OPS(add)
 138 ATOMIC_OPS(sub)
 139
 140 #undef ATOMIC_OPS
 141 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
 142
 143 ATOMIC_OPS(and)
 144 ATOMIC_OPS(or)
 145 ATOMIC_OPS(xor)
 146
 147 #undef ATOMIC_OPS
 148 #undef ATOMIC_FETCH_OP
 149 #undef ATOMIC_OP_RETURN
 150 #undef ATOMIC_OP
 151
 152 /**
 153  * atomic_fetch_add_unless - add unless the number is a given value
 154  * @v: pointer to value
 155  * @a: amount to add
 156  * @u: unless value is equal to u
 157  *
 158  * Returns old value.
 159  *
 160  */
 161
 162 static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
 163 {
 164         int __oldval;
 165         register int tmp;
 166
 167         asm volatile(
 168                 "1:     %0 = memw_locked(%2);"
 169                 "       {"
 170                 "               p3 = cmp.eq(%0, %4);"
 171                 "               if (p3.new) jump:nt 2f;"
 172                 "               %1 = add(%0, %3);"
 173                 "       }"
 174                 "       memw_locked(%2, p3) = %1;"
 175                 "       {"
 176                 "               if !p3 jump 1b;"
 177                 "       }"
 178                 "2:"
 179                 : "=&r" (__oldval), "=&r" (tmp)
 180                 : "r" (v), "r" (a), "r" (u)
 181                 : "memory", "p3"
 182         );
 183         return __oldval;
 184 }
 185 #define atomic_fetch_add_unless atomic_fetch_add_unless
 186
 187 #endif