1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_COMPILER_TYPES_H 3 #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead." 4 #endif 5 6 /* 7 * Common definitions for all gcc versions go here. 8 */ 9 #define GCC_VERSION (__GNUC__ * 10000 \ 10 + __GNUC_MINOR__ * 100 \ 11 + __GNUC_PATCHLEVEL__) 12 13 #if GCC_VERSION < 40600 14 # error Sorry, your compiler is too old - please upgrade it. 15 #elif defined(CONFIG_ARM64) && GCC_VERSION < 50100 16 /* 17 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293 18 * https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk 19 */ 20 # error Sorry, your version of GCC is too old - please use 5.1 or newer. 21 #endif 22 23 /* 24 * This macro obfuscates arithmetic on a variable address so that gcc 25 * shouldn't recognize the original var, and make assumptions about it. 26 * 27 * This is needed because the C standard makes it undefined to do 28 * pointer arithmetic on "objects" outside their boundaries and the 29 * gcc optimizers assume this is the case. In particular they 30 * assume such arithmetic does not wrap. 31 * 32 * A miscompilation has been observed because of this on PPC. 33 * To work around it we hide the relationship of the pointer and the object 34 * using this macro. 35 * 36 * Versions of the ppc64 compiler before 4.1 had a bug where use of 37 * RELOC_HIDE could trash r30. The bug can be worked around by changing 38 * the inline assembly constraint from =g to =r, in this particular 39 * case either is valid. 40 */ 41 #define RELOC_HIDE(ptr, off) \ 42 ({ \ 43 unsigned long __ptr; \ 44 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ 45 (typeof(ptr)) (__ptr + (off)); \ 46 }) 47 48 /* 49 * A trick to suppress uninitialized variable warning without generating any 50 * code 51 */ 52 #define uninitialized_var(x) x = x 53 54 #ifdef __CHECKER__ 55 #define __must_be_array(a) 0 56 #else 57 /* &a[0] degrades to a pointer: a different type from an array */ 58 #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) 59 #endif 60 61 #ifdef CONFIG_RETPOLINE 62 #define __noretpoline __attribute__((indirect_branch("keep"))) 63 #endif 64 65 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) 66 67 #define __optimize(level) __attribute__((__optimize__(level))) 68 69 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) 70 71 #ifndef __CHECKER__ 72 #define __compiletime_warning(message) __attribute__((warning(message))) 73 #define __compiletime_error(message) __attribute__((error(message))) 74 75 #ifdef LATENT_ENTROPY_PLUGIN 76 #define __latent_entropy __attribute__((latent_entropy)) 77 #endif 78 #endif /* __CHECKER__ */ 79 80 /* 81 * calling noreturn functions, __builtin_unreachable() and __builtin_trap() 82 * confuse the stack allocation in gcc, leading to overly large stack 83 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 84 * 85 * Adding an empty inline assembly before it works around the problem 86 */ 87 #define barrier_before_unreachable() asm volatile("") 88 89 /* 90 * Mark a position in code as unreachable. This can be used to 91 * suppress control flow warnings after asm blocks that transfer 92 * control elsewhere. 93 * 94 * Early snapshots of gcc 4.5 don't support this and we can't detect 95 * this in the preprocessor, but we can live with this because they're 96 * unreleased. Really, we need to have autoconf for the kernel. 97 */ 98 #define unreachable() \ 99 do { \ 100 annotate_unreachable(); \ 101 barrier_before_unreachable(); \ 102 __builtin_unreachable(); \ 103 } while (0) 104 105 /* Mark a function definition as prohibited from being cloned. */ 106 #define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) 107 108 #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__) 109 #define __randomize_layout __attribute__((randomize_layout)) 110 #define __no_randomize_layout __attribute__((no_randomize_layout)) 111 /* This anon struct can add padding, so only enable it under randstruct. */ 112 #define randomized_struct_fields_start struct { 113 #define randomized_struct_fields_end } __randomize_layout; 114 #endif 115 116 /* 117 * When used with Link Time Optimization, gcc can optimize away C functions or 118 * variables which are referenced only from assembly code. __visible tells the 119 * optimizer that something else uses this function or variable, thus preventing 120 * this. 121 */ 122 #define __visible __attribute__((externally_visible)) 123 124 /* gcc version specific checks */ 125 126 #if GCC_VERSION >= 40900 && !defined(__CHECKER__) 127 /* 128 * __assume_aligned(n, k): Tell the optimizer that the returned 129 * pointer can be assumed to be k modulo n. The second argument is 130 * optional (default 0), so we use a variadic macro to make the 131 * shorthand. 132 * 133 * Beware: Do not apply this to functions which may return 134 * ERR_PTRs. Also, it is probably unwise to apply it to functions 135 * returning extra information in the low bits (but in that case the 136 * compiler should see some alignment anyway, when the return value is 137 * massaged by 'flags = ptr & 3; ptr &= ~3;'). 138 */ 139 #define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) 140 #endif 141 142 /* 143 * GCC 'asm goto' miscompiles certain code sequences: 144 * 145 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 146 * 147 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. 148 * 149 * (asm goto is automatically volatile - the naming reflects this.) 150 */ 151 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) 152 153 /* 154 * sparse (__CHECKER__) pretends to be gcc, but can't do constant 155 * folding in __builtin_bswap*() (yet), so don't set these for it. 156 */ 157 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__) 158 #define __HAVE_BUILTIN_BSWAP32__ 159 #define __HAVE_BUILTIN_BSWAP64__ 160 #if GCC_VERSION >= 40800 161 #define __HAVE_BUILTIN_BSWAP16__ 162 #endif 163 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */ 164 165 #if GCC_VERSION >= 70000 166 #define KASAN_ABI_VERSION 5 167 #elif GCC_VERSION >= 50000 168 #define KASAN_ABI_VERSION 4 169 #elif GCC_VERSION >= 40902 170 #define KASAN_ABI_VERSION 3 171 #endif 172 173 #if GCC_VERSION >= 40902 174 /* 175 * Tell the compiler that address safety instrumentation (KASAN) 176 * should not be applied to that function. 177 * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 178 */ 179 #define __no_sanitize_address __attribute__((no_sanitize_address)) 180 #endif 181 182 #if GCC_VERSION >= 50100 183 /* 184 * Mark structures as requiring designated initializers. 185 * https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html 186 */ 187 #define __designated_init __attribute__((designated_init)) 188 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 189 #endif 190 191 #if GCC_VERSION >= 90100 192 #define __copy(symbol) __attribute__((__copy__(symbol))) 193 #endif 194 195 #if !defined(__noclone) 196 #define __noclone /* not needed */ 197 #endif 198 199 #if !defined(__no_sanitize_address) 200 #define __no_sanitize_address 201 #endif 202 203 /* 204 * Turn individual warnings and errors on and off locally, depending 205 * on version. 206 */ 207 #define __diag_GCC(version, severity, s) \ 208 __diag_GCC_ ## version(__diag_GCC_ ## severity s) 209 210 /* Severity used in pragma directives */ 211 #define __diag_GCC_ignore ignored 212 #define __diag_GCC_warn warning 213 #define __diag_GCC_error error 214 215 #define __diag_str1(s) #s 216 #define __diag_str(s) __diag_str1(s) 217 #define __diag(s) _Pragma(__diag_str(GCC diagnostic s)) 218 219 #if GCC_VERSION >= 80000 220 #define __diag_GCC_8(s) __diag(s) 221 #else 222 #define __diag_GCC_8(s) 223 #endif 224