| 1 | /***************************************************************************** |
| 2 | * kernelutils-x386.h |
| 3 | * |
| 4 | * This file holds the code needed by LTT usertrace that comes from the |
| 5 | * kernel headers. Since including kernel headers is not recommended in |
| 6 | * userspace programs/libraries, we rewrote implementations HIGHLY INSPIRED |
| 7 | * (i.e. copied/pasted) from the original kernel headers (2.6.17). |
| 8 | * |
| 9 | * Martin Bisson, July 2006 |
| 10 | * Mathieu Desnoyers, August 2006 |
| 11 | */ |
| 12 | |
| 13 | #ifndef _KERNELUTILS_I386_H |
| 14 | #define _KERNELUTILS_I386_H |
| 15 | |
| 16 | #ifdef __cplusplus |
| 17 | extern "C" { |
| 18 | #endif |
| 19 | |
| 20 | // We are careful, so we assume a possibly SMP machine |
| 21 | #define LOCK "lock ; " |
| 22 | #define LOCK_PREFIX "lock ; " |
| 23 | |
| 24 | |
| 25 | // From atomic.h |
| 26 | |
| 27 | |
| 28 | /* |
| 29 | * Make sure gcc doesn't try to be clever and move things around |
| 30 | * on us. We need to use _exactly_ the address the user gave us, |
| 31 | * not some alias that contains the same information. |
| 32 | */ |
| 33 | typedef struct { volatile int counter; } atomic_t; |
| 34 | |
| 35 | |
| 36 | /** |
| 37 | * atomic_read - read atomic variable |
| 38 | * @v: pointer of type atomic_t |
| 39 | * |
| 40 | * Atomically reads the value of @v. |
| 41 | */ |
| 42 | #define atomic_read(v) ((v)->counter) |
| 43 | |
| 44 | /** |
| 45 | * atomic_add - add integer to atomic variable |
| 46 | * @i: integer value to add |
| 47 | * @v: pointer of type atomic_t |
| 48 | * |
| 49 | * Atomically adds @i to @v. |
| 50 | */ |
| 51 | static __inline__ void atomic_add(int i, atomic_t *v) |
| 52 | { |
| 53 | __asm__ __volatile__( |
| 54 | LOCK "addl %1,%0" |
| 55 | :"=m" (v->counter) |
| 56 | :"ir" (i), "m" (v->counter)); |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * atomic_inc - increment atomic variable |
| 61 | * @v: pointer of type atomic_t |
| 62 | * |
| 63 | * Atomically increments @v by 1. |
| 64 | */ |
| 65 | static __inline__ void atomic_inc(atomic_t *v) |
| 66 | { |
| 67 | __asm__ __volatile__( |
| 68 | LOCK "incl %0" |
| 69 | :"=m" (v->counter) |
| 70 | :"m" (v->counter)); |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * atomic_add_return - add and return |
| 75 | * @i: integer value to add |
| 76 | * @v: pointer of type atomic_t |
| 77 | * |
| 78 | * Atomically adds @i to @v and returns @i + @v |
| 79 | */ |
| 80 | static __inline__ int atomic_add_return(int i, atomic_t *v) |
| 81 | { |
| 82 | int __i = i; |
| 83 | __asm__ __volatile__( |
| 84 | LOCK "xaddl %0, %1;" |
| 85 | :"=r"(i) |
| 86 | :"m"(v->counter), "0"(i)); |
| 87 | return i + __i; |
| 88 | } |
| 89 | |
| 90 | |
| 91 | |
| 92 | |
| 93 | // From system.h |
| 94 | |
| 95 | struct __xchg_dummy { unsigned long a[100]; }; |
| 96 | #define __xg(x) ((struct __xchg_dummy *)(x)) |
| 97 | |
| 98 | |
| 99 | /* |
| 100 | * Atomic compare and exchange. Compare OLD with MEM, if identical, |
| 101 | * store NEW in MEM. Return the initial value in MEM. Success is |
| 102 | * indicated by comparing RETURN with OLD. |
| 103 | */ |
| 104 | |
| 105 | #define __HAVE_ARCH_CMPXCHG 1 |
| 106 | #define cmpxchg(ptr,o,n)\ |
| 107 | ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\ |
| 108 | (unsigned long)(n),sizeof(*(ptr)))) |
| 109 | |
| 110 | static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, |
| 111 | unsigned long newval, int size) |
| 112 | { |
| 113 | unsigned long prev; |
| 114 | switch (size) { |
| 115 | case 1: |
| 116 | __asm__ __volatile__(LOCK_PREFIX "cmpxchgb %b1,%2" |
| 117 | : "=a"(prev) |
| 118 | : "q"(newval), "m"(*__xg(ptr)), "0"(old) |
| 119 | : "memory"); |
| 120 | return prev; |
| 121 | case 2: |
| 122 | __asm__ __volatile__(LOCK_PREFIX "cmpxchgw %w1,%2" |
| 123 | : "=a"(prev) |
| 124 | : "r"(newval), "m"(*__xg(ptr)), "0"(old) |
| 125 | : "memory"); |
| 126 | return prev; |
| 127 | case 4: |
| 128 | __asm__ __volatile__(LOCK_PREFIX "cmpxchgl %1,%2" |
| 129 | : "=a"(prev) |
| 130 | : "r"(newval), "m"(*__xg(ptr)), "0"(old) |
| 131 | : "memory"); |
| 132 | return prev; |
| 133 | } |
| 134 | return old; |
| 135 | } |
| 136 | |
| 137 | |
| 138 | // From msr.h |
| 139 | |
| 140 | #define rdtscll(val) \ |
| 141 | __asm__ __volatile__("rdtsc" : "=A" (val)) |
| 142 | |
| 143 | // From timex.h |
| 144 | |
| 145 | typedef unsigned long long cycles_t; |
| 146 | |
| 147 | static inline cycles_t get_cycles (void) |
| 148 | { |
| 149 | unsigned long long ret; |
| 150 | |
| 151 | rdtscll(ret); |
| 152 | return ret; |
| 153 | } |
| 154 | |
| 155 | #ifdef __cplusplus |
| 156 | } /* end of extern "C" */ |
| 157 | #endif |
| 158 | |
| 159 | #endif // _KERNELUTILS_I386_H |