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 #endif 288