1 /* SPDX-License-Identifier: BSD-2-Clause */ 2 /* 3 * Copyright (c) 2014, STMicroelectronics International N.V. 4 */ 5 6 #ifndef COMPILER_H 7 #define COMPILER_H 8 9 /* 10 * Macros that should be used instead of using __attribute__ directly to 11 * ease portability and make the code easier to read. 12 * 13 * Some of the defines below is known to sometimes cause conflicts when 14 * this file is included from xtest in normal world. It is assumed that 15 * the conflicting defines has the same meaning in that environment. 16 * Surrounding the troublesome defines with #ifndef should be enough. 17 */ 18 #define __deprecated __attribute__((deprecated)) 19 #ifndef __packed 20 #define __packed __attribute__((packed)) 21 #endif 22 #define __weak __attribute__((weak)) 23 #ifndef __noreturn 24 #define __noreturn __attribute__((noreturn)) 25 #endif 26 #define __pure __attribute__((pure)) 27 #define __aligned(x) __attribute__((aligned(x))) 28 #define __printf(a, b) __attribute__((format(printf, a, b))) 29 #define __noinline __attribute__((noinline)) 30 #define __attr_const __attribute__((__const__)) 31 #ifndef __unused 32 #define __unused __attribute__((unused)) 33 #endif 34 #define __maybe_unused __attribute__((unused)) 35 #ifndef __used 36 #define __used __attribute__((__used__)) 37 #endif 38 #define __must_check __attribute__((warn_unused_result)) 39 #define __cold __attribute__((__cold__)) 40 #define __section(x) __attribute__((section(x))) 41 #define __data __section(".data") 42 #define __bss __section(".bss") 43 #define __rodata __section(".rodata") 44 #define __rodata_unpaged __section(".rodata.__unpaged") 45 #define __early_ta __section(".rodata.early_ta") 46 #define __noprof __attribute__((no_instrument_function)) 47 48 #define __compiler_bswap64(x) __builtin_bswap64((x)) 49 #define __compiler_bswap32(x) __builtin_bswap32((x)) 50 #define __compiler_bswap16(x) __builtin_bswap16((x)) 51 52 #define __GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + \ 53 __GNUC_PATCHLEVEL__) 54 55 #if __GCC_VERSION >= 50100 && !defined(__CHECKER__) 56 #define __HAVE_BUILTIN_OVERFLOW 1 57 #endif 58 59 #ifdef __HAVE_BUILTIN_OVERFLOW 60 #define __compiler_add_overflow(a, b, res) \ 61 __builtin_add_overflow((a), (b), (res)) 62 63 #define __compiler_sub_overflow(a, b, res) \ 64 __builtin_sub_overflow((a), (b), (res)) 65 66 #define __compiler_mul_overflow(a, b, res) \ 67 __builtin_mul_overflow((a), (b), (res)) 68 #else /*!__HAVE_BUILTIN_OVERFLOW*/ 69 70 /* 71 * Copied/inspired from https://www.fefe.de/intof.html 72 */ 73 74 #define __INTOF_ASSIGN(dest, src) (__extension__({ \ 75 typeof(src) __intof_x = (src); \ 76 typeof(dest) __intof_y = __intof_x; \ 77 (((uintmax_t)__intof_x == (uintmax_t)__intof_y) && \ 78 ((__intof_x < 1) == (__intof_y < 1)) ? \ 79 (void)((dest) = __intof_y) , 0 : 1); \ 80 })) 81 82 #define __INTOF_ADD(c, a, b) (__extension__({ \ 83 typeof(a) __intofa_a = (a); \ 84 typeof(b) __intofa_b = (b); \ 85 intmax_t __intofa_a_signed = __intofa_a; \ 86 uintmax_t __intofa_a_unsigned = __intofa_a; \ 87 intmax_t __intofa_b_signed = __intofa_b; \ 88 uintmax_t __intofa_b_unsigned = __intofa_b; \ 89 \ 90 __intofa_b < 1 ? \ 91 __intofa_a < 1 ? \ 92 ((INTMAX_MIN - __intofa_b_signed <= \ 93 __intofa_a_signed)) ? \ 94 __INTOF_ASSIGN((c), __intofa_a_signed + \ 95 __intofa_b_signed) : 1 \ 96 : \ 97 ((__intofa_a_unsigned >= (uintmax_t)-__intofa_b) ? \ 98 __INTOF_ASSIGN((c), __intofa_a_unsigned + \ 99 __intofa_b_signed) \ 100 : \ 101 __INTOF_ASSIGN((c), \ 102 (intmax_t)(__intofa_a_unsigned + \ 103 __intofa_b_signed))) \ 104 : \ 105 __intofa_a < 1 ? \ 106 ((__intofa_b_unsigned >= (uintmax_t)-__intofa_a) ? \ 107 __INTOF_ASSIGN((c), __intofa_a_signed + \ 108 __intofa_b_unsigned) \ 109 : \ 110 __INTOF_ASSIGN((c), \ 111 (intmax_t)(__intofa_a_signed + \ 112 __intofa_b_unsigned))) \ 113 : \ 114 ((UINTMAX_MAX - __intofa_b_unsigned >= \ 115 __intofa_a_unsigned) ? \ 116 __INTOF_ASSIGN((c), __intofa_a_unsigned + \ 117 __intofa_b_unsigned) : 1); \ 118 })) 119 120 #define __INTOF_SUB(c, a, b) (__extension__({ \ 121 typeof(a) __intofs_a = a; \ 122 typeof(b) __intofs_b = b; \ 123 intmax_t __intofs_a_signed = __intofs_a; \ 124 uintmax_t __intofs_a_unsigned = __intofs_a; \ 125 intmax_t __intofs_b_signed = __intofs_b; \ 126 uintmax_t __intofs_b_unsigned = __intofs_b; \ 127 \ 128 __intofs_b < 1 ? \ 129 __intofs_a < 1 ? \ 130 ((INTMAX_MAX + __intofs_b >= __intofs_a) ? \ 131 __INTOF_ASSIGN((c), __intofs_a_signed - \ 132 __intofs_b_signed) : 1) \ 133 : \ 134 (((uintmax_t)(UINTMAX_MAX + __intofs_b_signed) >= \ 135 __intofs_a_unsigned) ? \ 136 __INTOF_ASSIGN((c), __intofs_a - \ 137 __intofs_b) : 1) \ 138 : \ 139 __intofs_a < 1 ? \ 140 (((INTMAX_MIN + __intofs_b <= __intofs_a)) ? \ 141 __INTOF_ASSIGN((c), \ 142 (intmax_t)(__intofs_a_signed - \ 143 __intofs_b_unsigned)) : 1) \ 144 : \ 145 ((__intofs_b_unsigned <= __intofs_a_unsigned) ? \ 146 __INTOF_ASSIGN((c), __intofs_a_unsigned - \ 147 __intofs_b_unsigned) \ 148 : \ 149 __INTOF_ASSIGN((c), \ 150 (intmax_t)(__intofs_a_unsigned - \ 151 __intofs_b_unsigned))); \ 152 })) 153 154 /* 155 * Dealing with detecting overflow in multiplication of integers. 156 * 157 * First step is to remove two corner cases with the minum signed integer 158 * which can't be represented as a positive integer + sign. 159 * Multiply with 0 or 1 can't overflow, no checking needed of the operation, 160 * only if it can be assigned to the result. 161 * 162 * After the corner cases are eliminated we convert the two factors to 163 * positive unsigned values, keeping track of the original in another 164 * variable which is used at the end to determine the sign of the product. 165 * 166 * The two terms (a and b) are divided into upper and lower half (x1 upper 167 * and x0 lower), so the product is: 168 * ((a1 << hshift) + a0) * ((b1 << hshift) + b0) 169 * which also is: 170 * ((a1 * b1) << (hshift * 2)) + (T1) 171 * ((a1 * b0 + a0 * b1) << hshift) + (T2) 172 * (a0 * b0) (T3) 173 * 174 * From this we can tell and (a1 * b1) has to be 0 or we'll overflow, that 175 * is, at least one of a1 or b1 has to be 0. Once this has been checked the 176 * addition: ((a1 * b0) << hshift) + ((a0 * b1) << hshift) 177 * isn't an addition as one of the terms will be 0. 178 * 179 * Since each factor in: (a0 * b0) 180 * only uses half the capicity of the underlaying type it can't overflow 181 * 182 * The addition of T2 and T3 can overflow so we use __INTOF_ADD() to 183 * perform that addition. If the addition succeeds without overflow the 184 * result is assigned the required sign and checked for overflow again. 185 */ 186 187 #define __intof_mul_negate ((__intof_oa < 1) != (__intof_ob < 1)) 188 #define __intof_mul_hshift (sizeof(uintmax_t) * 8 / 2) 189 #define __intof_mul_hmask (UINTMAX_MAX >> __intof_mul_hshift) 190 #define __intof_mul_a0 ((uintmax_t)(__intof_a) >> __intof_mul_hshift) 191 #define __intof_mul_b0 ((uintmax_t)(__intof_b) >> __intof_mul_hshift) 192 #define __intof_mul_a1 ((uintmax_t)(__intof_a) & __intof_mul_hmask) 193 #define __intof_mul_b1 ((uintmax_t)(__intof_b) & __intof_mul_hmask) 194 #define __intof_mul_t (__intof_mul_a1 * __intof_mul_b0 + \ 195 __intof_mul_a0 * __intof_mul_b1) 196 197 #define __INTOF_MUL(c, a, b) (__extension__({ \ 198 typeof(a) __intof_oa = (a); \ 199 typeof(a) __intof_a = __intof_oa < 1 ? -__intof_oa : __intof_oa; \ 200 typeof(b) __intof_ob = (b); \ 201 typeof(b) __intof_b = __intof_ob < 1 ? -__intof_ob : __intof_ob; \ 202 typeof(c) __intof_c; \ 203 \ 204 __intof_oa == 0 || __intof_ob == 0 || \ 205 __intof_oa == 1 || __intof_ob == 1 ? \ 206 __INTOF_ASSIGN((c), __intof_oa * __intof_ob) : \ 207 (__intof_mul_a0 && __intof_mul_b0) || \ 208 __intof_mul_t > __intof_mul_hmask ? 1 : \ 209 __INTOF_ADD((__intof_c), __intof_mul_t << __intof_mul_hshift, \ 210 __intof_mul_a1 * __intof_mul_b1) ? 1 : \ 211 __intof_mul_negate ? __INTOF_ASSIGN((c), -__intof_c) : \ 212 __INTOF_ASSIGN((c), __intof_c); \ 213 })) 214 215 #define __compiler_add_overflow(a, b, res) __INTOF_ADD(*(res), (a), (b)) 216 #define __compiler_sub_overflow(a, b, res) __INTOF_SUB(*(res), (a), (b)) 217 #define __compiler_mul_overflow(a, b, res) __INTOF_MUL(*(res), (a), (b)) 218 219 #endif /*!__HAVE_BUILTIN_OVERFLOW*/ 220 221 #define __compiler_compare_and_swap(p, oval, nval) \ 222 __atomic_compare_exchange_n((p), (oval), (nval), true, \ 223 __ATOMIC_ACQUIRE, __ATOMIC_RELAXED) \ 224 225 #define __compiler_atomic_load(p) __atomic_load_n((p), __ATOMIC_RELAXED) 226 #define __compiler_atomic_store(p, val) \ 227 __atomic_store_n((p), (val), __ATOMIC_RELAXED) 228 229 #endif /*COMPILER_H*/ 230