1 #ifndef _LINUX_KERNEL_H 2 #define _LINUX_KERNEL_H 3 4 #include <linux/types.h> 5 #include <linux/printk.h> /* for printf/pr_* utilities */ 6 7 #define USHRT_MAX ((u16)(~0U)) 8 #define SHRT_MAX ((s16)(USHRT_MAX>>1)) 9 #define SHRT_MIN ((s16)(-SHRT_MAX - 1)) 10 #define INT_MAX ((int)(~0U>>1)) 11 #define INT_MIN (-INT_MAX - 1) 12 #define UINT_MAX (~0U) 13 #define LONG_MAX ((long)(~0UL>>1)) 14 #define LONG_MIN (-LONG_MAX - 1) 15 #define ULONG_MAX (~0UL) 16 #define LLONG_MAX ((long long)(~0ULL>>1)) 17 #define LLONG_MIN (-LLONG_MAX - 1) 18 #define ULLONG_MAX (~0ULL) 19 #ifndef SIZE_MAX 20 #define SIZE_MAX (~(size_t)0) 21 #endif 22 23 #define U8_MAX ((u8)~0U) 24 #define S8_MAX ((s8)(U8_MAX>>1)) 25 #define S8_MIN ((s8)(-S8_MAX - 1)) 26 #define U16_MAX ((u16)~0U) 27 #define S16_MAX ((s16)(U16_MAX>>1)) 28 #define S16_MIN ((s16)(-S16_MAX - 1)) 29 #define U32_MAX ((u32)~0U) 30 #define S32_MAX ((s32)(U32_MAX>>1)) 31 #define S32_MIN ((s32)(-S32_MAX - 1)) 32 #define U64_MAX ((u64)~0ULL) 33 #define S64_MAX ((s64)(U64_MAX>>1)) 34 #define S64_MIN ((s64)(-S64_MAX - 1)) 35 36 /* Aliases defined by stdint.h */ 37 #define UINT32_MAX U32_MAX 38 #define UINT64_MAX U64_MAX 39 40 #define INT32_MAX S32_MAX 41 42 #define STACK_MAGIC 0xdeadbeef 43 44 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) 45 46 #define ALIGN(x,a) __ALIGN_MASK((x),(typeof(x))(a)-1) 47 #define ALIGN_DOWN(x, a) ALIGN((x) - ((a) - 1), (a)) 48 #define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask)) 49 #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a))) 50 #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) 51 52 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) 53 54 /* 55 * This looks more complex than it should be. But we need to 56 * get the type for the ~ right in round_down (it needs to be 57 * as wide as the result!), and we want to evaluate the macro 58 * arguments just once each. 59 */ 60 #define __round_mask(x, y) ((__typeof__(x))((y)-1)) 61 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) 62 #define round_down(x, y) ((x) & ~__round_mask(x, y)) 63 64 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) 65 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) 66 67 #define DIV_ROUND_DOWN_ULL(ll, d) \ 68 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; }) 69 70 #define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d)) 71 72 #if BITS_PER_LONG == 32 73 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d) 74 #else 75 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d) 76 #endif 77 78 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */ 79 #define roundup(x, y) ( \ 80 { \ 81 const typeof(y) __y = y; \ 82 (((x) + (__y - 1)) / __y) * __y; \ 83 } \ 84 ) 85 #define rounddown(x, y) ( \ 86 { \ 87 typeof(x) __x = (x); \ 88 __x - (__x % (y)); \ 89 } \ 90 ) 91 92 /* 93 * Divide positive or negative dividend by positive divisor and round 94 * to closest integer. Result is undefined for negative divisors and 95 * for negative dividends if the divisor variable type is unsigned. 96 */ 97 #define DIV_ROUND_CLOSEST(x, divisor)( \ 98 { \ 99 typeof(x) __x = x; \ 100 typeof(divisor) __d = divisor; \ 101 (((typeof(x))-1) > 0 || \ 102 ((typeof(divisor))-1) > 0 || (__x) > 0) ? \ 103 (((__x) + ((__d) / 2)) / (__d)) : \ 104 (((__x) - ((__d) / 2)) / (__d)); \ 105 } \ 106 ) 107 /* 108 * Same as above but for u64 dividends. divisor must be a 32-bit 109 * number. 110 */ 111 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \ 112 { \ 113 typeof(divisor) __d = divisor; \ 114 unsigned long long _tmp = (x) + (__d) / 2; \ 115 do_div(_tmp, __d); \ 116 _tmp; \ 117 } \ 118 ) 119 120 /* 121 * Multiplies an integer by a fraction, while avoiding unnecessary 122 * overflow or loss of precision. 123 */ 124 #define mult_frac(x, numer, denom)( \ 125 { \ 126 typeof(x) quot = (x) / (denom); \ 127 typeof(x) rem = (x) % (denom); \ 128 (quot * (numer)) + ((rem * (numer)) / (denom)); \ 129 } \ 130 ) 131 132 /** 133 * upper_32_bits - return bits 32-63 of a number 134 * @n: the number we're accessing 135 * 136 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress 137 * the "right shift count >= width of type" warning when that quantity is 138 * 32-bits. 139 */ 140 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) 141 142 /** 143 * lower_32_bits - return bits 0-31 of a number 144 * @n: the number we're accessing 145 */ 146 #define lower_32_bits(n) ((u32)(n)) 147 148 /* 149 * abs() handles unsigned and signed longs, ints, shorts and chars. For all 150 * input types abs() returns a signed long. 151 * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64() 152 * for those. 153 */ 154 #define abs(x) ({ \ 155 long ret; \ 156 if (sizeof(x) == sizeof(long)) { \ 157 long __x = (x); \ 158 ret = (__x < 0) ? -__x : __x; \ 159 } else { \ 160 int __x = (x); \ 161 ret = (__x < 0) ? -__x : __x; \ 162 } \ 163 ret; \ 164 }) 165 166 #define abs64(x) ({ \ 167 s64 __x = (x); \ 168 (__x < 0) ? -__x : __x; \ 169 }) 170 171 /* 172 * min()/max()/clamp() macros that also do 173 * strict type-checking.. See the 174 * "unnecessary" pointer comparison. 175 */ 176 #define min(x, y) ({ \ 177 typeof(x) _min1 = (x); \ 178 typeof(y) _min2 = (y); \ 179 (void) (&_min1 == &_min2); \ 180 _min1 < _min2 ? _min1 : _min2; }) 181 182 #define max(x, y) ({ \ 183 typeof(x) _max1 = (x); \ 184 typeof(y) _max2 = (y); \ 185 (void) (&_max1 == &_max2); \ 186 _max1 > _max2 ? _max1 : _max2; }) 187 188 #define min3(x, y, z) min((typeof(x))min(x, y), z) 189 #define max3(x, y, z) max((typeof(x))max(x, y), z) 190 191 /** 192 * min_not_zero - return the minimum that is _not_ zero, unless both are zero 193 * @x: value1 194 * @y: value2 195 */ 196 #define min_not_zero(x, y) ({ \ 197 typeof(x) __x = (x); \ 198 typeof(y) __y = (y); \ 199 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); }) 200 201 /** 202 * clamp - return a value clamped to a given range with strict typechecking 203 * @val: current value 204 * @lo: lowest allowable value 205 * @hi: highest allowable value 206 * 207 * This macro does strict typechecking of lo/hi to make sure they are of the 208 * same type as val. See the unnecessary pointer comparisons. 209 */ 210 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi) 211 212 /* 213 * ..and if you can't take the strict 214 * types, you can specify one yourself. 215 * 216 * Or not use min/max/clamp at all, of course. 217 */ 218 #define min_t(type, x, y) ({ \ 219 type __min1 = (x); \ 220 type __min2 = (y); \ 221 __min1 < __min2 ? __min1: __min2; }) 222 223 #define max_t(type, x, y) ({ \ 224 type __max1 = (x); \ 225 type __max2 = (y); \ 226 __max1 > __max2 ? __max1: __max2; }) 227 228 /** 229 * clamp_t - return a value clamped to a given range using a given type 230 * @type: the type of variable to use 231 * @val: current value 232 * @lo: minimum allowable value 233 * @hi: maximum allowable value 234 * 235 * This macro does no typechecking and uses temporary variables of type 236 * 'type' to make all the comparisons. 237 */ 238 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) 239 240 /** 241 * clamp_val - return a value clamped to a given range using val's type 242 * @val: current value 243 * @lo: minimum allowable value 244 * @hi: maximum allowable value 245 * 246 * This macro does no typechecking and uses temporary variables of whatever 247 * type the input argument 'val' is. This is useful when val is an unsigned 248 * type and min and max are literals that will otherwise be assigned a signed 249 * integer type. 250 */ 251 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi) 252 253 254 /* 255 * swap - swap value of @a and @b 256 */ 257 #define swap(a, b) \ 258 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) 259 260 /** 261 * container_of - cast a member of a structure out to the containing structure 262 * @ptr: the pointer to the member. 263 * @type: the type of the container struct this is embedded in. 264 * @member: the name of the member within the struct. 265 * 266 */ 267 #define container_of(ptr, type, member) ({ \ 268 const typeof( ((type *)0)->member ) *__mptr = (ptr); \ 269 (type *)( (char *)__mptr - offsetof(type,member) );}) 270 271 #endif 272