kernel.h 7.0 KB

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  1. #ifndef _LINUX_KERNEL_H
  2. #define _LINUX_KERNEL_H
  3. #include <linux/types.h>
  4. #define USHRT_MAX ((u16)(~0U))
  5. #define SHRT_MAX ((s16)(USHRT_MAX>>1))
  6. #define SHRT_MIN ((s16)(-SHRT_MAX - 1))
  7. #define INT_MAX ((int)(~0U>>1))
  8. #define INT_MIN (-INT_MAX - 1)
  9. #define UINT_MAX (~0U)
  10. #define LONG_MAX ((long)(~0UL>>1))
  11. #define LONG_MIN (-LONG_MAX - 1)
  12. #define ULONG_MAX (~0UL)
  13. #define LLONG_MAX ((long long)(~0ULL>>1))
  14. #define LLONG_MIN (-LLONG_MAX - 1)
  15. #define ULLONG_MAX (~0ULL)
  16. #define SIZE_MAX (~(size_t)0)
  17. #define U8_MAX ((u8)~0U)
  18. #define S8_MAX ((s8)(U8_MAX>>1))
  19. #define S8_MIN ((s8)(-S8_MAX - 1))
  20. #define U16_MAX ((u16)~0U)
  21. #define S16_MAX ((s16)(U16_MAX>>1))
  22. #define S16_MIN ((s16)(-S16_MAX - 1))
  23. #define U32_MAX ((u32)~0U)
  24. #define S32_MAX ((s32)(U32_MAX>>1))
  25. #define S32_MIN ((s32)(-S32_MAX - 1))
  26. #define U64_MAX ((u64)~0ULL)
  27. #define S64_MAX ((s64)(U64_MAX>>1))
  28. #define S64_MIN ((s64)(-S64_MAX - 1))
  29. #define STACK_MAGIC 0xdeadbeef
  30. #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
  31. #define ALIGN(x,a) __ALIGN_MASK((x),(typeof(x))(a)-1)
  32. #define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
  33. #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
  34. #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
  35. #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  36. /*
  37. * This looks more complex than it should be. But we need to
  38. * get the type for the ~ right in round_down (it needs to be
  39. * as wide as the result!), and we want to evaluate the macro
  40. * arguments just once each.
  41. */
  42. #define __round_mask(x, y) ((__typeof__(x))((y)-1))
  43. #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  44. #define round_down(x, y) ((x) & ~__round_mask(x, y))
  45. #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  46. #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  47. #if BITS_PER_LONG == 32
  48. # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  49. #else
  50. # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  51. #endif
  52. /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  53. #define roundup(x, y) ( \
  54. { \
  55. const typeof(y) __y = y; \
  56. (((x) + (__y - 1)) / __y) * __y; \
  57. } \
  58. )
  59. #define rounddown(x, y) ( \
  60. { \
  61. typeof(x) __x = (x); \
  62. __x - (__x % (y)); \
  63. } \
  64. )
  65. /*
  66. * Divide positive or negative dividend by positive divisor and round
  67. * to closest integer. Result is undefined for negative divisors and
  68. * for negative dividends if the divisor variable type is unsigned.
  69. */
  70. #define DIV_ROUND_CLOSEST(x, divisor)( \
  71. { \
  72. typeof(x) __x = x; \
  73. typeof(divisor) __d = divisor; \
  74. (((typeof(x))-1) > 0 || \
  75. ((typeof(divisor))-1) > 0 || (__x) > 0) ? \
  76. (((__x) + ((__d) / 2)) / (__d)) : \
  77. (((__x) - ((__d) / 2)) / (__d)); \
  78. } \
  79. )
  80. /*
  81. * Multiplies an integer by a fraction, while avoiding unnecessary
  82. * overflow or loss of precision.
  83. */
  84. #define mult_frac(x, numer, denom)( \
  85. { \
  86. typeof(x) quot = (x) / (denom); \
  87. typeof(x) rem = (x) % (denom); \
  88. (quot * (numer)) + ((rem * (numer)) / (denom)); \
  89. } \
  90. )
  91. /**
  92. * upper_32_bits - return bits 32-63 of a number
  93. * @n: the number we're accessing
  94. *
  95. * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
  96. * the "right shift count >= width of type" warning when that quantity is
  97. * 32-bits.
  98. */
  99. #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  100. /**
  101. * lower_32_bits - return bits 0-31 of a number
  102. * @n: the number we're accessing
  103. */
  104. #define lower_32_bits(n) ((u32)(n))
  105. /*
  106. * abs() handles unsigned and signed longs, ints, shorts and chars. For all
  107. * input types abs() returns a signed long.
  108. * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
  109. * for those.
  110. */
  111. #define abs(x) ({ \
  112. long ret; \
  113. if (sizeof(x) == sizeof(long)) { \
  114. long __x = (x); \
  115. ret = (__x < 0) ? -__x : __x; \
  116. } else { \
  117. int __x = (x); \
  118. ret = (__x < 0) ? -__x : __x; \
  119. } \
  120. ret; \
  121. })
  122. #define abs64(x) ({ \
  123. s64 __x = (x); \
  124. (__x < 0) ? -__x : __x; \
  125. })
  126. /*
  127. * min()/max()/clamp() macros that also do
  128. * strict type-checking.. See the
  129. * "unnecessary" pointer comparison.
  130. */
  131. #define min(x, y) ({ \
  132. typeof(x) _min1 = (x); \
  133. typeof(y) _min2 = (y); \
  134. _min1 < _min2 ? _min1 : _min2; })
  135. #define max(x, y) ({ \
  136. typeof(x) _max1 = (x); \
  137. typeof(y) _max2 = (y); \
  138. _max1 > _max2 ? _max1 : _max2; })
  139. #define min3(x, y, z) ({ \
  140. typeof(x) _min1 = (x); \
  141. typeof(y) _min2 = (y); \
  142. typeof(z) _min3 = (z); \
  143. _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
  144. (_min2 < _min3 ? _min2 : _min3); })
  145. #define max3(x, y, z) ({ \
  146. typeof(x) _max1 = (x); \
  147. typeof(y) _max2 = (y); \
  148. typeof(z) _max3 = (z); \
  149. _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
  150. (_max2 > _max3 ? _max2 : _max3); })
  151. /**
  152. * min_not_zero - return the minimum that is _not_ zero, unless both are zero
  153. * @x: value1
  154. * @y: value2
  155. */
  156. #define min_not_zero(x, y) ({ \
  157. typeof(x) __x = (x); \
  158. typeof(y) __y = (y); \
  159. __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
  160. /**
  161. * clamp - return a value clamped to a given range with strict typechecking
  162. * @val: current value
  163. * @lo: lowest allowable value
  164. * @hi: highest allowable value
  165. *
  166. * This macro does strict typechecking of lo/hi to make sure they are of the
  167. * same type as val. See the unnecessary pointer comparisons.
  168. */
  169. #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
  170. /*
  171. * ..and if you can't take the strict
  172. * types, you can specify one yourself.
  173. *
  174. * Or not use min/max/clamp at all, of course.
  175. */
  176. #define min_t(type, x, y) ({ \
  177. type __min1 = (x); \
  178. type __min2 = (y); \
  179. __min1 < __min2 ? __min1: __min2; })
  180. #define max_t(type, x, y) ({ \
  181. type __max1 = (x); \
  182. type __max2 = (y); \
  183. __max1 > __max2 ? __max1: __max2; })
  184. /**
  185. * clamp_t - return a value clamped to a given range using a given type
  186. * @type: the type of variable to use
  187. * @val: current value
  188. * @lo: minimum allowable value
  189. * @hi: maximum allowable value
  190. *
  191. * This macro does no typechecking and uses temporary variables of type
  192. * 'type' to make all the comparisons.
  193. */
  194. #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
  195. /**
  196. * clamp_val - return a value clamped to a given range using val's type
  197. * @val: current value
  198. * @lo: minimum allowable value
  199. * @hi: maximum allowable value
  200. *
  201. * This macro does no typechecking and uses temporary variables of whatever
  202. * type the input argument 'val' is. This is useful when val is an unsigned
  203. * type and min and max are literals that will otherwise be assigned a signed
  204. * integer type.
  205. */
  206. #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
  207. /*
  208. * swap - swap value of @a and @b
  209. */
  210. #define swap(a, b) \
  211. do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
  212. /**
  213. * container_of - cast a member of a structure out to the containing structure
  214. * @ptr: the pointer to the member.
  215. * @type: the type of the container struct this is embedded in.
  216. * @member: the name of the member within the struct.
  217. *
  218. */
  219. #define container_of(ptr, type, member) ({ \
  220. const typeof( ((type *)0)->member ) *__mptr = (ptr); \
  221. (type *)( (char *)__mptr - offsetof(type,member) );})
  222. #endif