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 /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 */ 14 #if GCC_VERSION < 40900 15 # error Sorry, your version of GCC is too old - please use 4.9 or newer. 16 #endif 17 18 /* Optimization barrier */ 19 20 /* The "volatile" is due to gcc bugs */ 21 #define barrier() __asm__ __volatile__("": : :"memory") 22 /* 23 * This version is i.e. to prevent dead stores elimination on @ptr 24 * where gcc and llvm may behave differently when otherwise using 25 * normal barrier(): while gcc behavior gets along with a normal 26 * barrier(), llvm needs an explicit input variable to be assumed 27 * clobbered. The issue is as follows: while the inline asm might 28 * access any memory it wants, the compiler could have fit all of 29 * @ptr into memory registers instead, and since @ptr never escaped 30 * from that, it proved that the inline asm wasn't touching any of 31 * it. This version works well with both compilers, i.e. we're telling 32 * the compiler that the inline asm absolutely may see the contents 33 * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 34 */ 35 #define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") 36 37 /* 38 * This macro obfuscates arithmetic on a variable address so that gcc 39 * shouldn't recognize the original var, and make assumptions about it. 40 * 41 * This is needed because the C standard makes it undefined to do 42 * pointer arithmetic on "objects" outside their boundaries and the 43 * gcc optimizers assume this is the case. In particular they 44 * assume such arithmetic does not wrap. 45 * 46 * A miscompilation has been observed because of this on PPC. 47 * To work around it we hide the relationship of the pointer and the object 48 * using this macro. 49 * 50 * Versions of the ppc64 compiler before 4.1 had a bug where use of 51 * RELOC_HIDE could trash r30. The bug can be worked around by changing 52 * the inline assembly constraint from =g to =r, in this particular 53 * case either is valid. 54 */ 55 #define RELOC_HIDE(ptr, off) \ 56 ({ \ 57 unsigned long __ptr; \ 58 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ 59 (typeof(ptr)) (__ptr + (off)); \ 60 }) 61 62 #ifdef CONFIG_RETPOLINE 63 #define __noretpoline __attribute__((__indirect_branch__("keep"))) 64 #endif 65 66 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) 67 68 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) 69 70 #define __compiletime_warning(message) __attribute__((__warning__(message))) 71 #define __compiletime_error(message) __attribute__((__error__(message))) 72 73 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) 74 #define __latent_entropy __attribute__((latent_entropy)) 75 #endif 76 77 /* 78 * calling noreturn functions, __builtin_unreachable() and __builtin_trap() 79 * confuse the stack allocation in gcc, leading to overly large stack 80 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 81 * 82 * Adding an empty inline assembly before it works around the problem 83 */ 84 #define barrier_before_unreachable() asm volatile("") 85 86 /* 87 * Mark a position in code as unreachable. This can be used to 88 * suppress control flow warnings after asm blocks that transfer 89 * control elsewhere. 90 */ 91 #define unreachable() \ 92 do { \ 93 annotate_unreachable(); \ 94 barrier_before_unreachable(); \ 95 __builtin_unreachable(); \ 96 } while (0) 97 98 #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__) 99 #define __randomize_layout __attribute__((randomize_layout)) 100 #define __no_randomize_layout __attribute__((no_randomize_layout)) 101 /* This anon struct can add padding, so only enable it under randstruct. */ 102 #define randomized_struct_fields_start struct { 103 #define randomized_struct_fields_end } __randomize_layout; 104 #endif 105 106 /* 107 * GCC 'asm goto' miscompiles certain code sequences: 108 * 109 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 110 * 111 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. 112 * 113 * (asm goto is automatically volatile - the naming reflects this.) 114 */ 115 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) 116 117 /* 118 * sparse (__CHECKER__) pretends to be gcc, but can't do constant 119 * folding in __builtin_bswap*() (yet), so don't set these for it. 120 */ 121 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__) 122 #define __HAVE_BUILTIN_BSWAP32__ 123 #define __HAVE_BUILTIN_BSWAP64__ 124 #define __HAVE_BUILTIN_BSWAP16__ 125 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */ 126 127 #if GCC_VERSION >= 70000 128 #define KASAN_ABI_VERSION 5 129 #elif GCC_VERSION >= 50000 130 #define KASAN_ABI_VERSION 4 131 #elif GCC_VERSION >= 40902 132 #define KASAN_ABI_VERSION 3 133 #endif 134 135 #if __has_attribute(__no_sanitize_address__) 136 #define __no_sanitize_address __attribute__((no_sanitize_address)) 137 #else 138 #define __no_sanitize_address 139 #endif 140 141 #if defined(__SANITIZE_THREAD__) && __has_attribute(__no_sanitize_thread__) 142 #define __no_sanitize_thread __attribute__((no_sanitize_thread)) 143 #else 144 #define __no_sanitize_thread 145 #endif 146 147 #if __has_attribute(__no_sanitize_undefined__) 148 #define __no_sanitize_undefined __attribute__((no_sanitize_undefined)) 149 #else 150 #define __no_sanitize_undefined 151 #endif 152 153 #if GCC_VERSION >= 50100 154 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 155 #endif 156 157 /* 158 * Turn individual warnings and errors on and off locally, depending 159 * on version. 160 */ 161 #define __diag_GCC(version, severity, s) \ 162 __diag_GCC_ ## version(__diag_GCC_ ## severity s) 163 164 /* Severity used in pragma directives */ 165 #define __diag_GCC_ignore ignored 166 #define __diag_GCC_warn warning 167 #define __diag_GCC_error error 168 169 #define __diag_str1(s) #s 170 #define __diag_str(s) __diag_str1(s) 171 #define __diag(s) _Pragma(__diag_str(GCC diagnostic s)) 172 173 #if GCC_VERSION >= 80000 174 #define __diag_GCC_8(s) __diag(s) 175 #else 176 #define __diag_GCC_8(s) 177 #endif 178 179 #define __no_fgcse __attribute__((optimize("-fno-gcse"))) 180