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 #ifdef __clang__ 44 #define __SECTION_FLAGS_RODATA 45 #else 46 /* 47 * Override sections flags/type generated by the C compiler to make sure they 48 * are: "a",%progbits (thus creating an allocatable, non-writeable, non- 49 * executable data section). 50 * The trailing COMMENT_CHAR comments out the flags generated by the compiler. 51 * This avoids a harmless warning with GCC. 52 */ 53 #if defined(__aarch64__) || defined(__arm__) 54 #define COMMENT_CHAR "//" 55 #else 56 #define COMMENT_CHAR "#" 57 #endif 58 #define __SECTION_FLAGS_RODATA ",\"a\",%progbits " COMMENT_CHAR 59 #endif 60 #define __rodata __section(".rodata" __SECTION_FLAGS_RODATA) 61 #define __rodata_dummy __section(".rodata.dummy" __SECTION_FLAGS_RODATA) 62 #define __rodata_unpaged(x) \ 63 __section(".rodata.__unpaged." x __SECTION_FLAGS_RODATA) 64 #ifdef CFG_VIRTUALIZATION 65 #define __nex_bss __section(".nex_bss") 66 #define __nex_data __section(".nex_data") 67 #else /* CFG_VIRTUALIZATION */ 68 #define __nex_bss 69 #define __nex_data 70 #endif /* CFG_VIRTUALIZATION */ 71 #define __noprof __attribute__((no_instrument_function)) 72 #define __nostackcheck __attribute__((no_instrument_function)) 73 74 #define __compiler_bswap64(x) __builtin_bswap64((x)) 75 #define __compiler_bswap32(x) __builtin_bswap32((x)) 76 #define __compiler_bswap16(x) __builtin_bswap16((x)) 77 78 #define __GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + \ 79 __GNUC_PATCHLEVEL__) 80 81 #if __GCC_VERSION >= 50100 && !defined(__CHECKER__) 82 #define __HAVE_BUILTIN_OVERFLOW 1 83 #endif 84 85 #if __GCC_VERSION >= 90100 && !defined(__CHECKER__) 86 #define __HAVE_SINGLE_ARGUMENT_STATIC_ASSERT 1 87 #endif 88 89 #ifdef __HAVE_BUILTIN_OVERFLOW 90 #define __compiler_add_overflow(a, b, res) \ 91 __builtin_add_overflow((a), (b), (res)) 92 93 #define __compiler_sub_overflow(a, b, res) \ 94 __builtin_sub_overflow((a), (b), (res)) 95 96 #define __compiler_mul_overflow(a, b, res) \ 97 __builtin_mul_overflow((a), (b), (res)) 98 #else /*!__HAVE_BUILTIN_OVERFLOW*/ 99 100 /* 101 * Copied/inspired from https://www.fefe.de/intof.html 102 */ 103 104 #define __INTOF_ASSIGN(dest, src) (__extension__({ \ 105 typeof(src) __intof_x = (src); \ 106 typeof(dest) __intof_y = __intof_x; \ 107 (((uintmax_t)__intof_x == (uintmax_t)__intof_y) && \ 108 ((__intof_x < 1) == (__intof_y < 1)) ? \ 109 (void)((dest) = __intof_y) , 0 : 1); \ 110 })) 111 112 #define __INTOF_ADD(c, a, b) (__extension__({ \ 113 typeof(a) __intofa_a = (a); \ 114 typeof(b) __intofa_b = (b); \ 115 intmax_t __intofa_a_signed = __intofa_a; \ 116 uintmax_t __intofa_a_unsigned = __intofa_a; \ 117 intmax_t __intofa_b_signed = __intofa_b; \ 118 uintmax_t __intofa_b_unsigned = __intofa_b; \ 119 \ 120 __intofa_b < 1 ? \ 121 __intofa_a < 1 ? \ 122 ((INTMAX_MIN - __intofa_b_signed <= \ 123 __intofa_a_signed)) ? \ 124 __INTOF_ASSIGN((c), __intofa_a_signed + \ 125 __intofa_b_signed) : 1 \ 126 : \ 127 ((__intofa_a_unsigned >= (uintmax_t)-__intofa_b) ? \ 128 __INTOF_ASSIGN((c), __intofa_a_unsigned + \ 129 __intofa_b_signed) \ 130 : \ 131 __INTOF_ASSIGN((c), \ 132 (intmax_t)(__intofa_a_unsigned + \ 133 __intofa_b_signed))) \ 134 : \ 135 __intofa_a < 1 ? \ 136 ((__intofa_b_unsigned >= (uintmax_t)-__intofa_a) ? \ 137 __INTOF_ASSIGN((c), __intofa_a_signed + \ 138 __intofa_b_unsigned) \ 139 : \ 140 __INTOF_ASSIGN((c), \ 141 (intmax_t)(__intofa_a_signed + \ 142 __intofa_b_unsigned))) \ 143 : \ 144 ((UINTMAX_MAX - __intofa_b_unsigned >= \ 145 __intofa_a_unsigned) ? \ 146 __INTOF_ASSIGN((c), __intofa_a_unsigned + \ 147 __intofa_b_unsigned) : 1); \ 148 })) 149 150 #define __INTOF_SUB(c, a, b) (__extension__({ \ 151 typeof(a) __intofs_a = a; \ 152 typeof(b) __intofs_b = b; \ 153 intmax_t __intofs_a_signed = __intofs_a; \ 154 uintmax_t __intofs_a_unsigned = __intofs_a; \ 155 intmax_t __intofs_b_signed = __intofs_b; \ 156 uintmax_t __intofs_b_unsigned = __intofs_b; \ 157 \ 158 __intofs_b < 1 ? \ 159 __intofs_a < 1 ? \ 160 ((INTMAX_MAX + __intofs_b_signed >= \ 161 __intofs_a_signed) ? \ 162 __INTOF_ASSIGN((c), __intofs_a_signed - \ 163 __intofs_b_signed) : 1) \ 164 : \ 165 (((uintmax_t)(UINTMAX_MAX + __intofs_b_signed) >= \ 166 __intofs_a_unsigned) ? \ 167 __INTOF_ASSIGN((c), __intofs_a - \ 168 __intofs_b) : 1) \ 169 : \ 170 __intofs_a < 1 ? \ 171 (((intmax_t)(INTMAX_MIN + __intofs_b) <= \ 172 __intofs_a_signed) ? \ 173 __INTOF_ASSIGN((c), \ 174 (intmax_t)(__intofs_a_signed - \ 175 __intofs_b_unsigned)) : 1) \ 176 : \ 177 ((__intofs_b_unsigned <= __intofs_a_unsigned) ? \ 178 __INTOF_ASSIGN((c), __intofs_a_unsigned - \ 179 __intofs_b_unsigned) \ 180 : \ 181 __INTOF_ASSIGN((c), \ 182 (intmax_t)(__intofs_a_unsigned - \ 183 __intofs_b_unsigned))); \ 184 })) 185 186 /* 187 * Dealing with detecting overflow in multiplication of integers. 188 * 189 * First step is to remove two corner cases with the minum signed integer 190 * which can't be represented as a positive integer + sign. 191 * Multiply with 0 or 1 can't overflow, no checking needed of the operation, 192 * only if it can be assigned to the result. 193 * 194 * After the corner cases are eliminated we convert the two factors to 195 * positive unsigned values, keeping track of the original in another 196 * variable which is used at the end to determine the sign of the product. 197 * 198 * The two terms (a and b) are divided into upper and lower half (x1 upper 199 * and x0 lower), so the product is: 200 * ((a1 << hshift) + a0) * ((b1 << hshift) + b0) 201 * which also is: 202 * ((a1 * b1) << (hshift * 2)) + (T1) 203 * ((a1 * b0 + a0 * b1) << hshift) + (T2) 204 * (a0 * b0) (T3) 205 * 206 * From this we can tell and (a1 * b1) has to be 0 or we'll overflow, that 207 * is, at least one of a1 or b1 has to be 0. Once this has been checked the 208 * addition: ((a1 * b0) << hshift) + ((a0 * b1) << hshift) 209 * isn't an addition as one of the terms will be 0. 210 * 211 * Since each factor in: (a0 * b0) 212 * only uses half the capicity of the underlaying type it can't overflow 213 * 214 * The addition of T2 and T3 can overflow so we use __INTOF_ADD() to 215 * perform that addition. If the addition succeeds without overflow the 216 * result is assigned the required sign and checked for overflow again. 217 */ 218 219 #define __intof_mul_negate ((__intof_oa < 1) != (__intof_ob < 1)) 220 #define __intof_mul_hshift (sizeof(uintmax_t) * 8 / 2) 221 #define __intof_mul_hmask (UINTMAX_MAX >> __intof_mul_hshift) 222 #define __intof_mul_a0 ((uintmax_t)(__intof_a) >> __intof_mul_hshift) 223 #define __intof_mul_b0 ((uintmax_t)(__intof_b) >> __intof_mul_hshift) 224 #define __intof_mul_a1 ((uintmax_t)(__intof_a) & __intof_mul_hmask) 225 #define __intof_mul_b1 ((uintmax_t)(__intof_b) & __intof_mul_hmask) 226 #define __intof_mul_t (__intof_mul_a1 * __intof_mul_b0 + \ 227 __intof_mul_a0 * __intof_mul_b1) 228 229 #define __INTOF_MUL(c, a, b) (__extension__({ \ 230 typeof(a) __intof_oa = (a); \ 231 typeof(a) __intof_a = __intof_oa < 1 ? -__intof_oa : __intof_oa; \ 232 typeof(b) __intof_ob = (b); \ 233 typeof(b) __intof_b = __intof_ob < 1 ? -__intof_ob : __intof_ob; \ 234 typeof(c) __intof_c; \ 235 \ 236 __intof_oa == 0 || __intof_ob == 0 || \ 237 __intof_oa == 1 || __intof_ob == 1 ? \ 238 __INTOF_ASSIGN((c), __intof_oa * __intof_ob) : \ 239 (__intof_mul_a0 && __intof_mul_b0) || \ 240 __intof_mul_t > __intof_mul_hmask ? 1 : \ 241 __INTOF_ADD((__intof_c), __intof_mul_t << __intof_mul_hshift, \ 242 __intof_mul_a1 * __intof_mul_b1) ? 1 : \ 243 __intof_mul_negate ? __INTOF_ASSIGN((c), -__intof_c) : \ 244 __INTOF_ASSIGN((c), __intof_c); \ 245 })) 246 247 #define __compiler_add_overflow(a, b, res) __INTOF_ADD(*(res), (a), (b)) 248 #define __compiler_sub_overflow(a, b, res) __INTOF_SUB(*(res), (a), (b)) 249 #define __compiler_mul_overflow(a, b, res) __INTOF_MUL(*(res), (a), (b)) 250 251 #endif /*!__HAVE_BUILTIN_OVERFLOW*/ 252 253 #define __compiler_compare_and_swap(p, oval, nval) \ 254 __atomic_compare_exchange_n((p), (oval), (nval), true, \ 255 __ATOMIC_ACQUIRE, __ATOMIC_RELAXED) \ 256 257 #define __compiler_atomic_load(p) __atomic_load_n((p), __ATOMIC_RELAXED) 258 #define __compiler_atomic_store(p, val) \ 259 __atomic_store_n((p), (val), __ATOMIC_RELAXED) 260 261 #define barrier() asm volatile ("" : : : "memory") 262 263 #ifndef __has_attribute 264 #define __has_attribute(x) 0 265 #endif 266 267 #if __has_attribute(__fallthrough__) 268 #define fallthrough __attribute__((__fallthrough__)) 269 #else 270 #define fallthrough do {} while (0) /* fallthrough */ 271 #endif 272 273 #endif /*COMPILER_H*/ 274