| 33,19 → 33,43 |
|---|
| |
| typedef struct { volatile __u64 count; } atomic_t; |
| |
| /* |
| * TODO: these are just placeholders for real implementations of atomic_inc and atomic_dec. |
| * WARNING: the following functions cause the code to be preemption-unsafe !!! |
| /** Atomic add operation. |
| * |
| * Use atomic compare and swap operation to atomically add signed value. |
| * |
| * @param val Atomic variable. |
| * @param i Signed value to be added. |
| * |
| * @return Value of the atomic variable as it existed before addition. |
| */ |
| static inline count_t atomic_add(atomic_t *val, int i) |
| { |
| __u64 a, b; |
| volatile __u64 x = (__u64) &val->count; |
| |
| __asm__ volatile ( |
| "0:\n" |
| "ldx %0, %1\n" |
| "add %1, %3, %2\n" |
| "casx %0, %1, %2\n" |
| "cmp %1, %2\n" |
| "bne 0b\n" |
| "nop\n" |
| : "=m" (*((__u64 *)x)), "=r" (a), "=r" (b) |
| : "r" (i) |
| ); |
| |
| return a; |
| } |
| |
| static inline void atomic_inc(atomic_t *val) |
| { |
| val->count++; |
| (void) atomic_add(val, 1); |
| } |
| |
| static inline void atomic_dec(atomic_t *val) |
| { |
| val->count--; |
| (void) atomic_add(val, -1); |
| } |
| |
| static inline void atomic_set(atomic_t *val, __u64 i) |