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#ifndef SSIZE_MAX 23#define SSIZE_MAX ((ssize_t)(SIZE_MAX >> 1)) 24#endif 25 26#define U8_MAX ((u8)~0U) 27#define S8_MAX ((s8)(U8_MAX>>1)) 28#define S8_MIN ((s8)(-S8_MAX - 1)) 29#define U16_MAX ((u16)~0U) 30#define S16_MAX ((s16)(U16_MAX>>1)) 31#define S16_MIN ((s16)(-S16_MAX - 1)) 32#define U32_MAX ((u32)~0U) 33#define S32_MAX ((s32)(U32_MAX>>1)) 34#define S32_MIN ((s32)(-S32_MAX - 1)) 35#define U64_MAX ((u64)~0ULL) 36#define S64_MAX ((s64)(U64_MAX>>1)) 37#define S64_MIN ((s64)(-S64_MAX - 1)) 38 39/* Aliases defined by stdint.h */ 40#define UINT32_MAX U32_MAX 41#define UINT64_MAX U64_MAX 42 43#define INT32_MAX S32_MAX 44 45#define STACK_MAGIC 0xdeadbeef 46 47#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) 48 49#define ALIGN(x,a) __ALIGN_MASK((x),(typeof(x))(a)-1) 50#define ALIGN_DOWN(x, a) ALIGN((x) - ((a) - 1), (a)) 51#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask)) 52#define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a))) 53#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) 54 55#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) 56 57/* 58 * This looks more complex than it should be. But we need to 59 * get the type for the ~ right in round_down (it needs to be 60 * as wide as the result!), and we want to evaluate the macro 61 * arguments just once each. 62 */ 63#define __round_mask(x, y) ((__typeof__(x))((y)-1)) 64#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) 65#define round_down(x, y) ((x) & ~__round_mask(x, y)) 66 67#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) 68#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) 69 70#define DIV_ROUND_DOWN_ULL(ll, d) \ 71 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; }) 72 73#define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d)) 74 75#define ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 76 77#if BITS_PER_LONG == 32 78# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d) 79#else 80# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d) 81#endif 82 83/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */ 84#define roundup(x, y) ( \ 85{ \ 86 const typeof(y) __y = y; \ 87 (((x) + (__y - 1)) / __y) * __y; \ 88} \ 89) 90#define rounddown(x, y) ( \ 91{ \ 92 typeof(x) __x = (x); \ 93 __x - (__x % (y)); \ 94} \ 95) 96 97/* 98 * Divide positive or negative dividend by positive divisor and round 99 * to closest integer. Result is undefined for negative divisors and 100 * for negative dividends if the divisor variable type is unsigned. 101 */ 102#define DIV_ROUND_CLOSEST(x, divisor)( \ 103{ \ 104 typeof(x) __x = x; \ 105 typeof(divisor) __d = divisor; \ 106 (((typeof(x))-1) > 0 || \ 107 ((typeof(divisor))-1) > 0 || (__x) > 0) ? \ 108 (((__x) + ((__d) / 2)) / (__d)) : \ 109 (((__x) - ((__d) / 2)) / (__d)); \ 110} \ 111) 112/* 113 * Same as above but for u64 dividends. divisor must be a 32-bit 114 * number. 115 */ 116#define DIV_ROUND_CLOSEST_ULL(x, divisor)( \ 117{ \ 118 typeof(divisor) __d = divisor; \ 119 unsigned long long _tmp = (x) + (__d) / 2; \ 120 do_div(_tmp, __d); \ 121 _tmp; \ 122} \ 123) 124 125/* 126 * Multiplies an integer by a fraction, while avoiding unnecessary 127 * overflow or loss of precision. 128 */ 129#define mult_frac(x, numer, denom)( \ 130{ \ 131 typeof(x) quot = (x) / (denom); \ 132 typeof(x) rem = (x) % (denom); \ 133 (quot * (numer)) + ((rem * (numer)) / (denom)); \ 134} \ 135) 136 137/** 138 * upper_32_bits - return bits 32-63 of a number 139 * @n: the number we're accessing 140 * 141 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress 142 * the "right shift count >= width of type" warning when that quantity is 143 * 32-bits. 144 */ 145#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) 146 147/** 148 * lower_32_bits - return bits 0-31 of a number 149 * @n: the number we're accessing 150 */ 151#define lower_32_bits(n) ((u32)(n)) 152 153/* 154 * abs() handles unsigned and signed longs, ints, shorts and chars. For all 155 * input types abs() returns a signed long. 156 * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64() 157 * for those. 158 */ 159#define abs(x) ({ \ 160 long ret; \ 161 if (sizeof(x) == sizeof(long)) { \ 162 long __x = (x); \ 163 ret = (__x < 0) ? -__x : __x; \ 164 } else { \ 165 int __x = (x); \ 166 ret = (__x < 0) ? -__x : __x; \ 167 } \ 168 ret; \ 169 }) 170 171#define abs64(x) ({ \ 172 s64 __x = (x); \ 173 (__x < 0) ? -__x : __x; \ 174 }) 175 176/* 177 * min()/max()/clamp() macros that also do 178 * strict type-checking.. See the 179 * "unnecessary" pointer comparison. 180 */ 181#define min(x, y) ({ \ 182 typeof(x) _min1 = (x); \ 183 typeof(y) _min2 = (y); \ 184 (void) (&_min1 == &_min2); \ 185 _min1 < _min2 ? _min1 : _min2; }) 186 187#define max(x, y) ({ \ 188 typeof(x) _max1 = (x); \ 189 typeof(y) _max2 = (y); \ 190 (void) (&_max1 == &_max2); \ 191 _max1 > _max2 ? _max1 : _max2; }) 192 193#define min3(x, y, z) min((typeof(x))min(x, y), z) 194#define max3(x, y, z) max((typeof(x))max(x, y), z) 195 196/** 197 * min_not_zero - return the minimum that is _not_ zero, unless both are zero 198 * @x: value1 199 * @y: value2 200 */ 201#define min_not_zero(x, y) ({ \ 202 typeof(x) __x = (x); \ 203 typeof(y) __y = (y); \ 204 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); }) 205 206/** 207 * clamp - return a value clamped to a given range with strict typechecking 208 * @val: current value 209 * @lo: lowest allowable value 210 * @hi: highest allowable value 211 * 212 * This macro does strict typechecking of lo/hi to make sure they are of the 213 * same type as val. See the unnecessary pointer comparisons. 214 */ 215#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi) 216 217/* 218 * ..and if you can't take the strict 219 * types, you can specify one yourself. 220 * 221 * Or not use min/max/clamp at all, of course. 222 */ 223#define min_t(type, x, y) ({ \ 224 type __min1 = (x); \ 225 type __min2 = (y); \ 226 __min1 < __min2 ? __min1: __min2; }) 227 228#define max_t(type, x, y) ({ \ 229 type __max1 = (x); \ 230 type __max2 = (y); \ 231 __max1 > __max2 ? __max1: __max2; }) 232 233/** 234 * clamp_t - return a value clamped to a given range using a given type 235 * @type: the type of variable to use 236 * @val: current value 237 * @lo: minimum allowable value 238 * @hi: maximum allowable value 239 * 240 * This macro does no typechecking and uses temporary variables of type 241 * 'type' to make all the comparisons. 242 */ 243#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) 244 245/** 246 * clamp_val - return a value clamped to a given range using val's type 247 * @val: current value 248 * @lo: minimum allowable value 249 * @hi: maximum allowable value 250 * 251 * This macro does no typechecking and uses temporary variables of whatever 252 * type the input argument 'val' is. This is useful when val is an unsigned 253 * type and min and max are literals that will otherwise be assigned a signed 254 * integer type. 255 */ 256#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi) 257 258 259/* 260 * swap - swap value of @a and @b 261 */ 262#define swap(a, b) \ 263 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) 264 265/** 266 * container_of - cast a member of a structure out to the containing structure 267 * @ptr: the pointer to the member. 268 * @type: the type of the container struct this is embedded in. 269 * @member: the name of the member within the struct. 270 * 271 */ 272#define container_of(ptr, type, member) ({ \ 273 const typeof( ((type *)0)->member ) *__mptr = (ptr); \ 274 (type *)( (char *)__mptr - offsetof(type,member) );}) 275 276/* 277 * check_member() - Check the offset of a structure member 278 * 279 * @structure: Name of structure (e.g. global_data) 280 * @member: Name of member (e.g. baudrate) 281 * @offset: Expected offset in bytes 282 */ 283#define check_member(structure, member, offset) _Static_assert( \ 284 offsetof(struct structure, member) == (offset), \ 285 "`struct " #structure "` offset for `" #member "` is not " #offset) 286 287#define __find_closest(x, a, as, op) \ 288({ \ 289 typeof(as) __fc_i, __fc_as = (as) - 1; \ 290 typeof(x) __fc_x = (x); \ 291 typeof(*a) const *__fc_a = (a); \ 292 for (__fc_i = 0; __fc_i < __fc_as; __fc_i++) { \ 293 if (__fc_x op DIV_ROUND_CLOSEST(__fc_a[__fc_i] + \ 294 __fc_a[__fc_i + 1], 2)) \ 295 break; \ 296 } \ 297 (__fc_i); \ 298}) 299 300/** 301 * find_closest - locate the closest element in a sorted array 302 * @x: The reference value. 303 * @a: The array in which to look for the closest element. Must be sorted 304 * in ascending order. 305 * @as: Size of 'a'. 306 * 307 * Returns the index of the element closest to 'x'. 308 */ 309#define find_closest(x, a, as) __find_closest(x, a, as, <=) 310 311#endif 312