| 1 | // SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 2 | // |
| 3 | // SPDX-License-Identifier: LGPL-2.1-or-later |
| 4 | |
| 5 | #ifndef _URCU_COMPILER_H |
| 6 | #define _URCU_COMPILER_H |
| 7 | |
| 8 | /* |
| 9 | * Compiler definitions. |
| 10 | */ |
| 11 | |
| 12 | #include <stddef.h> /* for offsetof */ |
| 13 | |
| 14 | #if defined __cplusplus |
| 15 | # include <type_traits> /* for std::remove_cv */ |
| 16 | #endif |
| 17 | |
| 18 | #include <urcu/config.h> |
| 19 | |
| 20 | #define caa_likely(x) __builtin_expect(!!(x), 1) |
| 21 | #define caa_unlikely(x) __builtin_expect(!!(x), 0) |
| 22 | |
| 23 | #ifdef CONFIG_RCU_USE_ATOMIC_BUILTINS |
| 24 | # define cmm_barrier() __atomic_signal_fence(__ATOMIC_SEQ_CST) |
| 25 | #else |
| 26 | # define cmm_barrier() __asm__ __volatile__ ("" : : : "memory") |
| 27 | #endif |
| 28 | |
| 29 | /* |
| 30 | * Instruct the compiler to perform only a single access to a variable |
| 31 | * (prohibits merging and refetching). The compiler is also forbidden to reorder |
| 32 | * successive instances of CMM_ACCESS_ONCE(), but only when the compiler is aware of |
| 33 | * particular ordering. Compiler ordering can be ensured, for example, by |
| 34 | * putting two CMM_ACCESS_ONCE() in separate C statements. |
| 35 | * |
| 36 | * This macro does absolutely -nothing- to prevent the CPU from reordering, |
| 37 | * merging, or refetching absolutely anything at any time. Its main intended |
| 38 | * use is to mediate communication between process-level code and irq/NMI |
| 39 | * handlers, all running on the same CPU. |
| 40 | */ |
| 41 | #define CMM_ACCESS_ONCE(x) (*(__volatile__ __typeof__(x) *)&(x)) |
| 42 | |
| 43 | #ifndef caa_max |
| 44 | #define caa_max(a,b) ((a)>(b)?(a):(b)) |
| 45 | #endif |
| 46 | |
| 47 | #ifndef caa_min |
| 48 | #define caa_min(a,b) ((a)<(b)?(a):(b)) |
| 49 | #endif |
| 50 | |
| 51 | #if defined(__SIZEOF_LONG__) |
| 52 | #define CAA_BITS_PER_LONG (__SIZEOF_LONG__ * 8) |
| 53 | #elif defined(_LP64) |
| 54 | #define CAA_BITS_PER_LONG 64 |
| 55 | #else |
| 56 | #define CAA_BITS_PER_LONG 32 |
| 57 | #endif |
| 58 | |
| 59 | /* |
| 60 | * caa_container_of - Get the address of an object containing a field. |
| 61 | * |
| 62 | * @ptr: pointer to the field. |
| 63 | * @type: type of the object. |
| 64 | * @member: name of the field within the object. |
| 65 | */ |
| 66 | #define caa_container_of(ptr, type, member) \ |
| 67 | __extension__ \ |
| 68 | ({ \ |
| 69 | const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \ |
| 70 | (type *)((char *)__ptr - offsetof(type, member)); \ |
| 71 | }) |
| 72 | |
| 73 | /* |
| 74 | * caa_container_of_check_null - Get the address of an object containing a field. |
| 75 | * |
| 76 | * @ptr: pointer to the field. |
| 77 | * @type: type of the object. |
| 78 | * @member: name of the field within the object. |
| 79 | * |
| 80 | * Return the address of the object containing the field. Return NULL if |
| 81 | * @ptr is NULL. |
| 82 | */ |
| 83 | #define caa_container_of_check_null(ptr, type, member) \ |
| 84 | __extension__ \ |
| 85 | ({ \ |
| 86 | const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \ |
| 87 | (__ptr) ? (type *)((char *)__ptr - offsetof(type, member)) : NULL; \ |
| 88 | }) |
| 89 | |
| 90 | #define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); })) |
| 91 | #define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond)) |
| 92 | |
| 93 | /* |
| 94 | * __rcu is an annotation that documents RCU pointer accesses that need |
| 95 | * to be protected by a read-side critical section. Eventually, a static |
| 96 | * checker will be able to use this annotation to detect incorrect RCU |
| 97 | * usage. |
| 98 | */ |
| 99 | #define __rcu |
| 100 | |
| 101 | #ifdef __cplusplus |
| 102 | #define URCU_FORCE_CAST(_type, arg) (reinterpret_cast<typename std::remove_cv<_type>::type>(arg)) |
| 103 | #else |
| 104 | #define URCU_FORCE_CAST(type, arg) ((type) (arg)) |
| 105 | #endif |
| 106 | |
| 107 | #define caa_is_signed_type(type) ((type) -1 < (type) 0) |
| 108 | |
| 109 | /* |
| 110 | * Cast to unsigned long, sign-extending if @v is signed. |
| 111 | * Note: casting to a larger type or to same type size keeps the sign of |
| 112 | * the expression being cast (see C99 6.3.1.3). |
| 113 | */ |
| 114 | #define caa_cast_long_keep_sign(v) ((unsigned long) (v)) |
| 115 | |
| 116 | #if defined (__GNUC__) \ |
| 117 | && ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5) \ |
| 118 | || __GNUC__ >= 5) |
| 119 | #define CDS_DEPRECATED(msg) \ |
| 120 | __attribute__((deprecated(msg))) |
| 121 | #else |
| 122 | #define CDS_DEPRECATED(msg) \ |
| 123 | __attribute__((deprecated)) |
| 124 | #endif |
| 125 | |
| 126 | #define CAA_ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) |
| 127 | |
| 128 | /* |
| 129 | * URCU_GCC_VERSION is used to blacklist specific GCC versions with known |
| 130 | * bugs, clang also defines these macros to an equivalent GCC version it |
| 131 | * claims to support, so exclude it. |
| 132 | */ |
| 133 | #if defined(__GNUC__) && !defined(__clang__) |
| 134 | # define URCU_GCC_VERSION (__GNUC__ * 10000 \ |
| 135 | + __GNUC_MINOR__ * 100 \ |
| 136 | + __GNUC_PATCHLEVEL__) |
| 137 | #endif |
| 138 | |
| 139 | #ifdef __cplusplus |
| 140 | #define caa_unqual_scalar_typeof(x) \ |
| 141 | std::remove_cv<std::remove_reference<decltype(x)>::type>::type |
| 142 | #else |
| 143 | #define caa_scalar_type_to_expr(type) \ |
| 144 | unsigned type: (unsigned type)0, \ |
| 145 | signed type: (signed type)0 |
| 146 | |
| 147 | /* |
| 148 | * Use C11 _Generic to express unqualified type from expression. This removes |
| 149 | * volatile qualifier from expression type. |
| 150 | */ |
| 151 | #define caa_unqual_scalar_typeof(x) \ |
| 152 | __typeof__( \ |
| 153 | _Generic((x), \ |
| 154 | char: (char)0, \ |
| 155 | caa_scalar_type_to_expr(char), \ |
| 156 | caa_scalar_type_to_expr(short), \ |
| 157 | caa_scalar_type_to_expr(int), \ |
| 158 | caa_scalar_type_to_expr(long), \ |
| 159 | caa_scalar_type_to_expr(long long), \ |
| 160 | default: (x) \ |
| 161 | ) \ |
| 162 | ) |
| 163 | #endif |
| 164 | |
| 165 | /* |
| 166 | * Allow user to manually define CMM_SANITIZE_THREAD if their toolchain is not |
| 167 | * supported by this check. |
| 168 | */ |
| 169 | #ifndef CMM_SANITIZE_THREAD |
| 170 | # if defined(__GNUC__) && defined(__SANITIZE_THREAD__) |
| 171 | # define CMM_SANITIZE_THREAD |
| 172 | # elif defined(__clang__) && defined(__has_feature) |
| 173 | # if __has_feature(thread_sanitizer) |
| 174 | # define CMM_SANITIZE_THREAD |
| 175 | # endif |
| 176 | # endif |
| 177 | #endif /* !CMM_SANITIZE_THREAD */ |
| 178 | |
| 179 | /* |
| 180 | * Helper to add the volatile qualifier to a pointer. |
| 181 | */ |
| 182 | #if defined __cplusplus |
| 183 | template <typename T> |
| 184 | volatile T cmm_cast_volatile(T t) |
| 185 | { |
| 186 | return static_cast<volatile T>(t); |
| 187 | } |
| 188 | #else |
| 189 | # define cmm_cast_volatile(ptr) \ |
| 190 | __extension__ \ |
| 191 | ({ \ |
| 192 | (volatile __typeof__(ptr))(ptr); \ |
| 193 | }) |
| 194 | #endif |
| 195 | |
| 196 | /* |
| 197 | * Compile time assertion. |
| 198 | * - predicate: boolean expression to evaluate, |
| 199 | * - msg: string to print to the user on failure when `static_assert()` is |
| 200 | * supported, |
| 201 | * - c_identifier_msg: message to be included in the typedef to emulate a |
| 202 | * static assertion. This parameter must be a valid C identifier as it will |
| 203 | * be used as a typedef name. |
| 204 | */ |
| 205 | #ifdef __cplusplus |
| 206 | #define urcu_static_assert(predicate, msg, c_identifier_msg) \ |
| 207 | static_assert(predicate, msg) |
| 208 | #elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) |
| 209 | #define urcu_static_assert(predicate, msg, c_identifier_msg) \ |
| 210 | _Static_assert(predicate, msg) |
| 211 | #else |
| 212 | /* |
| 213 | * Evaluates the predicate and emit a compilation error on failure. |
| 214 | * |
| 215 | * If the predicate evaluates to true, this macro emits a function |
| 216 | * prototype with an argument type which is an array of size 0. |
| 217 | * |
| 218 | * If the predicate evaluates to false, this macro emits a function |
| 219 | * prototype with an argument type which is an array of negative size |
| 220 | * which is invalid in C and forces a compiler error. The |
| 221 | * c_identifier_msg parameter is used as the argument identifier so it |
| 222 | * is printed to the user when the error is reported. |
| 223 | */ |
| 224 | #define urcu_static_assert(predicate, msg, c_identifier_msg) \ |
| 225 | void urcu_static_assert_proto(char c_identifier_msg[2*!!(predicate)-1]) |
| 226 | #endif |
| 227 | |
| 228 | #endif /* _URCU_COMPILER_H */ |