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 #endif 16 17 /* Optimization barrier */ 18 19 /* The "volatile" is due to gcc bugs */ 20 #define barrier() __asm__ __volatile__("": : :"memory") 21 /* 22 * This version is i.e. to prevent dead stores elimination on @ptr 23 * where gcc and llvm may behave differently when otherwise using 24 * normal barrier(): while gcc behavior gets along with a normal 25 * barrier(), llvm needs an explicit input variable to be assumed 26 * clobbered. The issue is as follows: while the inline asm might 27 * access any memory it wants, the compiler could have fit all of 28 * @ptr into memory registers instead, and since @ptr never escaped 29 * from that, it proved that the inline asm wasn't touching any of 30 * it. This version works well with both compilers, i.e. we're telling 31 * the compiler that the inline asm absolutely may see the contents 32 * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 33 */ 34 #define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") 35 36 /* 37 * This macro obfuscates arithmetic on a variable address so that gcc 38 * shouldn't recognize the original var, and make assumptions about it. 39 * 40 * This is needed because the C standard makes it undefined to do 41 * pointer arithmetic on "objects" outside their boundaries and the 42 * gcc optimizers assume this is the case. In particular they 43 * assume such arithmetic does not wrap. 44 * 45 * A miscompilation has been observed because of this on PPC. 46 * To work around it we hide the relationship of the pointer and the object 47 * using this macro. 48 * 49 * Versions of the ppc64 compiler before 4.1 had a bug where use of 50 * RELOC_HIDE could trash r30. The bug can be worked around by changing 51 * the inline assembly constraint from =g to =r, in this particular 52 * case either is valid. 53 */ 54 #define RELOC_HIDE(ptr, off) \ 55 ({ \ 56 unsigned long __ptr; \ 57 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ 58 (typeof(ptr)) (__ptr + (off)); \ 59 }) 60 61 /* Make the optimizer believe the variable can be manipulated arbitrarily. */ 62 #define OPTIMIZER_HIDE_VAR(var) \ 63 __asm__ ("" : "=r" (var) : "0" (var)) 64 65 /* 66 * A trick to suppress uninitialized variable warning without generating any 67 * code 68 */ 69 #define uninitialized_var(x) x = x 70 71 #ifdef RETPOLINE 72 #define __noretpoline __attribute__((__indirect_branch__("keep"))) 73 #endif 74 75 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) 76 77 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) 78 79 #define __compiletime_warning(message) __attribute__((__warning__(message))) 80 #define __compiletime_error(message) __attribute__((__error__(message))) 81 82 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) 83 #define __latent_entropy __attribute__((latent_entropy)) 84 #endif 85 86 /* 87 * calling noreturn functions, __builtin_unreachable() and __builtin_trap() 88 * confuse the stack allocation in gcc, leading to overly large stack 89 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 90 * 91 * Adding an empty inline assembly before it works around the problem 92 */ 93 #define barrier_before_unreachable() asm volatile("") 94 95 /* 96 * Mark a position in code as unreachable. This can be used to 97 * suppress control flow warnings after asm blocks that transfer 98 * control elsewhere. 99 */ 100 #define unreachable() \ 101 do { \ 102 annotate_unreachable(); \ 103 barrier_before_unreachable(); \ 104 __builtin_unreachable(); \ 105 } while (0) 106 107 #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__) 108 #define __randomize_layout __attribute__((randomize_layout)) 109 #define __no_randomize_layout __attribute__((no_randomize_layout)) 110 /* This anon struct can add padding, so only enable it under randstruct. */ 111 #define randomized_struct_fields_start struct { 112 #define randomized_struct_fields_end } __randomize_layout; 113 #endif 114 115 /* 116 * GCC 'asm goto' miscompiles certain code sequences: 117 * 118 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 119 * 120 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. 121 * 122 * (asm goto is automatically volatile - the naming reflects this.) 123 */ 124 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) 125 126 /* 127 * sparse (__CHECKER__) pretends to be gcc, but can't do constant 128 * folding in __builtin_bswap*() (yet), so don't set these for it. 129 */ 130 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__) 131 #define __HAVE_BUILTIN_BSWAP32__ 132 #define __HAVE_BUILTIN_BSWAP64__ 133 #if GCC_VERSION >= 40800 134 #define __HAVE_BUILTIN_BSWAP16__ 135 #endif 136 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */ 137 138 #if GCC_VERSION >= 70000 139 #define KASAN_ABI_VERSION 5 140 #elif GCC_VERSION >= 50000 141 #define KASAN_ABI_VERSION 4 142 #elif GCC_VERSION >= 40902 143 #define KASAN_ABI_VERSION 3 144 #endif 145 146 #if __has_attribute(__no_sanitize_address__) 147 #define __no_sanitize_address __attribute__((no_sanitize_address)) 148 #else 149 #define __no_sanitize_address 150 #endif 151 152 #if GCC_VERSION >= 50100 153 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 154 #endif 155 156 /* 157 * Turn individual warnings and errors on and off locally, depending 158 * on version. 159 */ 160 #define __diag_GCC(version, severity, s) \ 161 __diag_GCC_ ## version(__diag_GCC_ ## severity s) 162 163 /* Severity used in pragma directives */ 164 #define __diag_GCC_ignore ignored 165 #define __diag_GCC_warn warning 166 #define __diag_GCC_error error 167 168 #define __diag_str1(s) #s 169 #define __diag_str(s) __diag_str1(s) 170 #define __diag(s) _Pragma(__diag_str(GCC diagnostic s)) 171 172 #if GCC_VERSION >= 80000 173 #define __diag_GCC_8(s) __diag(s) 174 #else 175 #define __diag_GCC_8(s) 176 #endif 177