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 /* 62 * A trick to suppress uninitialized variable warning without generating any 63 * code 64 */ 65 #define uninitialized_var(x) x = x 66 67 #ifdef CONFIG_RETPOLINE 68 #define __noretpoline __attribute__((__indirect_branch__("keep"))) 69 #endif 70 71 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) 72 73 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) 74 75 #define __compiletime_warning(message) __attribute__((__warning__(message))) 76 #define __compiletime_error(message) __attribute__((__error__(message))) 77 78 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) 79 #define __latent_entropy __attribute__((latent_entropy)) 80 #endif 81 82 /* 83 * calling noreturn functions, __builtin_unreachable() and __builtin_trap() 84 * confuse the stack allocation in gcc, leading to overly large stack 85 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 86 * 87 * Adding an empty inline assembly before it works around the problem 88 */ 89 #define barrier_before_unreachable() asm volatile("") 90 91 /* 92 * Mark a position in code as unreachable. This can be used to 93 * suppress control flow warnings after asm blocks that transfer 94 * control elsewhere. 95 */ 96 #define unreachable() \ 97 do { \ 98 annotate_unreachable(); \ 99 barrier_before_unreachable(); \ 100 __builtin_unreachable(); \ 101 } while (0) 102 103 #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__) 104 #define __randomize_layout __attribute__((randomize_layout)) 105 #define __no_randomize_layout __attribute__((no_randomize_layout)) 106 /* This anon struct can add padding, so only enable it under randstruct. */ 107 #define randomized_struct_fields_start struct { 108 #define randomized_struct_fields_end } __randomize_layout; 109 #endif 110 111 /* 112 * GCC 'asm goto' miscompiles certain code sequences: 113 * 114 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 115 * 116 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. 117 * 118 * (asm goto is automatically volatile - the naming reflects this.) 119 */ 120 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) 121 122 /* 123 * sparse (__CHECKER__) pretends to be gcc, but can't do constant 124 * folding in __builtin_bswap*() (yet), so don't set these for it. 125 */ 126 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__) 127 #define __HAVE_BUILTIN_BSWAP32__ 128 #define __HAVE_BUILTIN_BSWAP64__ 129 #if GCC_VERSION >= 40800 130 #define __HAVE_BUILTIN_BSWAP16__ 131 #endif 132 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */ 133 134 #if GCC_VERSION >= 70000 135 #define KASAN_ABI_VERSION 5 136 #elif GCC_VERSION >= 50000 137 #define KASAN_ABI_VERSION 4 138 #elif GCC_VERSION >= 40902 139 #define KASAN_ABI_VERSION 3 140 #endif 141 142 #if __has_attribute(__no_sanitize_address__) 143 #define __no_sanitize_address __attribute__((no_sanitize_address)) 144 #else 145 #define __no_sanitize_address 146 #endif 147 148 #if GCC_VERSION >= 50100 149 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 150 #endif 151 152 /* 153 * Turn individual warnings and errors on and off locally, depending 154 * on version. 155 */ 156 #define __diag_GCC(version, severity, s) \ 157 __diag_GCC_ ## version(__diag_GCC_ ## severity s) 158 159 /* Severity used in pragma directives */ 160 #define __diag_GCC_ignore ignored 161 #define __diag_GCC_warn warning 162 #define __diag_GCC_error error 163 164 #define __diag_str1(s) #s 165 #define __diag_str(s) __diag_str1(s) 166 #define __diag(s) _Pragma(__diag_str(GCC diagnostic s)) 167 168 #if GCC_VERSION >= 80000 169 #define __diag_GCC_8(s) __diag(s) 170 #else 171 #define __diag_GCC_8(s) 172 #endif 173 174 #define __no_fgcse __attribute__((optimize("-fno-gcse"))) 175