kernel.h 6.8 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247
  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. #ifndef SIZE_MAX
  17. #define SIZE_MAX (~(size_t)0)
  18. #endif
  19. #define U8_MAX ((u8)~0U)
  20. #define S8_MAX ((s8)(U8_MAX>>1))
  21. #define S8_MIN ((s8)(-S8_MAX - 1))
  22. #define U16_MAX ((u16)~0U)
  23. #define S16_MAX ((s16)(U16_MAX>>1))
  24. #define S16_MIN ((s16)(-S16_MAX - 1))
  25. #define U32_MAX ((u32)~0U)
  26. #define S32_MAX ((s32)(U32_MAX>>1))
  27. #define S32_MIN ((s32)(-S32_MAX - 1))
  28. #define U64_MAX ((u64)~0ULL)
  29. #define S64_MAX ((s64)(U64_MAX>>1))
  30. #define S64_MIN ((s64)(-S64_MAX - 1))
  31. #define STACK_MAGIC 0xdeadbeef
  32. #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
  33. #define ALIGN(x,a) __ALIGN_MASK((x),(typeof(x))(a)-1)
  34. #define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
  35. #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
  36. #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
  37. #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  38. /*
  39. * This looks more complex than it should be. But we need to
  40. * get the type for the ~ right in round_down (it needs to be
  41. * as wide as the result!), and we want to evaluate the macro
  42. * arguments just once each.
  43. */
  44. #define __round_mask(x, y) ((__typeof__(x))((y)-1))
  45. #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  46. #define round_down(x, y) ((x) & ~__round_mask(x, y))
  47. #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  48. #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  49. #if BITS_PER_LONG == 32
  50. # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  51. #else
  52. # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  53. #endif
  54. /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  55. #define roundup(x, y) ( \
  56. { \
  57. const typeof(y) __y = y; \
  58. (((x) + (__y - 1)) / __y) * __y; \
  59. } \
  60. )
  61. #define rounddown(x, y) ( \
  62. { \
  63. typeof(x) __x = (x); \
  64. __x - (__x % (y)); \
  65. } \
  66. )
  67. /*
  68. * Divide positive or negative dividend by positive divisor and round
  69. * to closest integer. Result is undefined for negative divisors and
  70. * for negative dividends if the divisor variable type is unsigned.
  71. */
  72. #define DIV_ROUND_CLOSEST(x, divisor)( \
  73. { \
  74. typeof(x) __x = x; \
  75. typeof(divisor) __d = divisor; \
  76. (((typeof(x))-1) > 0 || \
  77. ((typeof(divisor))-1) > 0 || (__x) > 0) ? \
  78. (((__x) + ((__d) / 2)) / (__d)) : \
  79. (((__x) - ((__d) / 2)) / (__d)); \
  80. } \
  81. )
  82. /*
  83. * Multiplies an integer by a fraction, while avoiding unnecessary
  84. * overflow or loss of precision.
  85. */
  86. #define mult_frac(x, numer, denom)( \
  87. { \
  88. typeof(x) quot = (x) / (denom); \
  89. typeof(x) rem = (x) % (denom); \
  90. (quot * (numer)) + ((rem * (numer)) / (denom)); \
  91. } \
  92. )
  93. /**
  94. * upper_32_bits - return bits 32-63 of a number
  95. * @n: the number we're accessing
  96. *
  97. * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
  98. * the "right shift count >= width of type" warning when that quantity is
  99. * 32-bits.
  100. */
  101. #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  102. /**
  103. * lower_32_bits - return bits 0-31 of a number
  104. * @n: the number we're accessing
  105. */
  106. #define lower_32_bits(n) ((u32)(n))
  107. /*
  108. * abs() handles unsigned and signed longs, ints, shorts and chars. For all
  109. * input types abs() returns a signed long.
  110. * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
  111. * for those.
  112. */
  113. #define abs(x) ({ \
  114. long ret; \
  115. if (sizeof(x) == sizeof(long)) { \
  116. long __x = (x); \
  117. ret = (__x < 0) ? -__x : __x; \
  118. } else { \
  119. int __x = (x); \
  120. ret = (__x < 0) ? -__x : __x; \
  121. } \
  122. ret; \
  123. })
  124. #define abs64(x) ({ \
  125. s64 __x = (x); \
  126. (__x < 0) ? -__x : __x; \
  127. })
  128. /*
  129. * min()/max()/clamp() macros that also do
  130. * strict type-checking.. See the
  131. * "unnecessary" pointer comparison.
  132. */
  133. #define min(x, y) ({ \
  134. typeof(x) _min1 = (x); \
  135. typeof(y) _min2 = (y); \
  136. (void) (&_min1 == &_min2); \
  137. _min1 < _min2 ? _min1 : _min2; })
  138. #define max(x, y) ({ \
  139. typeof(x) _max1 = (x); \
  140. typeof(y) _max2 = (y); \
  141. (void) (&_max1 == &_max2); \
  142. _max1 > _max2 ? _max1 : _max2; })
  143. #define min3(x, y, z) min((typeof(x))min(x, y), z)
  144. #define max3(x, y, z) max((typeof(x))max(x, y), z)
  145. /**
  146. * min_not_zero - return the minimum that is _not_ zero, unless both are zero
  147. * @x: value1
  148. * @y: value2
  149. */
  150. #define min_not_zero(x, y) ({ \
  151. typeof(x) __x = (x); \
  152. typeof(y) __y = (y); \
  153. __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
  154. /**
  155. * clamp - return a value clamped to a given range with strict typechecking
  156. * @val: current value
  157. * @lo: lowest allowable value
  158. * @hi: highest allowable value
  159. *
  160. * This macro does strict typechecking of lo/hi to make sure they are of the
  161. * same type as val. See the unnecessary pointer comparisons.
  162. */
  163. #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
  164. /*
  165. * ..and if you can't take the strict
  166. * types, you can specify one yourself.
  167. *
  168. * Or not use min/max/clamp at all, of course.
  169. */
  170. #define min_t(type, x, y) ({ \
  171. type __min1 = (x); \
  172. type __min2 = (y); \
  173. __min1 < __min2 ? __min1: __min2; })
  174. #define max_t(type, x, y) ({ \
  175. type __max1 = (x); \
  176. type __max2 = (y); \
  177. __max1 > __max2 ? __max1: __max2; })
  178. /**
  179. * clamp_t - return a value clamped to a given range using a given type
  180. * @type: the type of variable to use
  181. * @val: current value
  182. * @lo: minimum allowable value
  183. * @hi: maximum allowable value
  184. *
  185. * This macro does no typechecking and uses temporary variables of type
  186. * 'type' to make all the comparisons.
  187. */
  188. #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
  189. /**
  190. * clamp_val - return a value clamped to a given range using val's type
  191. * @val: current value
  192. * @lo: minimum allowable value
  193. * @hi: maximum allowable value
  194. *
  195. * This macro does no typechecking and uses temporary variables of whatever
  196. * type the input argument 'val' is. This is useful when val is an unsigned
  197. * type and min and max are literals that will otherwise be assigned a signed
  198. * integer type.
  199. */
  200. #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
  201. /*
  202. * swap - swap value of @a and @b
  203. */
  204. #define swap(a, b) \
  205. do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
  206. /**
  207. * container_of - cast a member of a structure out to the containing structure
  208. * @ptr: the pointer to the member.
  209. * @type: the type of the container struct this is embedded in.
  210. * @member: the name of the member within the struct.
  211. *
  212. */
  213. #define container_of(ptr, type, member) ({ \
  214. const typeof( ((type *)0)->member ) *__mptr = (ptr); \
  215. (type *)( (char *)__mptr - offsetof(type,member) );})
  216. #endif