OpenWrt – Blame information for rev 1
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Rev | Author | Line No. | Line |
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1 | office | 1 | --- /dev/null |
2 | +++ b/include/linux/compiler-gcc7.h |
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3 | @@ -0,0 +1,284 @@ |
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4 | +#ifndef __LINUX_COMPILER_H |
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5 | +#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead." |
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6 | +#endif |
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7 | + |
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8 | +/* |
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9 | + * Common definitions for all gcc versions go here. |
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10 | + */ |
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11 | +#define GCC_VERSION (__GNUC__ * 10000 \ |
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12 | + + __GNUC_MINOR__ * 100 \ |
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13 | + + __GNUC_PATCHLEVEL__) |
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14 | + |
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15 | +/* Optimization barrier */ |
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16 | + |
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17 | +/* The "volatile" is due to gcc bugs */ |
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18 | +#define barrier() __asm__ __volatile__("": : :"memory") |
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19 | +/* |
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20 | + * This version is i.e. to prevent dead stores elimination on @ptr |
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21 | + * where gcc and llvm may behave differently when otherwise using |
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22 | + * normal barrier(): while gcc behavior gets along with a normal |
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23 | + * barrier(), llvm needs an explicit input variable to be assumed |
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24 | + * clobbered. The issue is as follows: while the inline asm might |
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25 | + * access any memory it wants, the compiler could have fit all of |
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26 | + * @ptr into memory registers instead, and since @ptr never escaped |
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27 | + * from that, it proofed that the inline asm wasn't touching any of |
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28 | + * it. This version works well with both compilers, i.e. we're telling |
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29 | + * the compiler that the inline asm absolutely may see the contents |
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30 | + * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 |
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31 | + */ |
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32 | +#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") |
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33 | + |
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34 | +/* |
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35 | + * This macro obfuscates arithmetic on a variable address so that gcc |
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36 | + * shouldn't recognize the original var, and make assumptions about it. |
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37 | + * |
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38 | + * This is needed because the C standard makes it undefined to do |
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39 | + * pointer arithmetic on "objects" outside their boundaries and the |
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40 | + * gcc optimizers assume this is the case. In particular they |
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41 | + * assume such arithmetic does not wrap. |
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42 | + * |
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43 | + * A miscompilation has been observed because of this on PPC. |
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44 | + * To work around it we hide the relationship of the pointer and the object |
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45 | + * using this macro. |
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46 | + * |
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47 | + * Versions of the ppc64 compiler before 4.1 had a bug where use of |
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48 | + * RELOC_HIDE could trash r30. The bug can be worked around by changing |
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49 | + * the inline assembly constraint from =g to =r, in this particular |
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50 | + * case either is valid. |
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51 | + */ |
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52 | +#define RELOC_HIDE(ptr, off) \ |
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53 | +({ \ |
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54 | + unsigned long __ptr; \ |
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55 | + __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ |
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56 | + (typeof(ptr)) (__ptr + (off)); \ |
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57 | +}) |
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58 | + |
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59 | +/* Make the optimizer believe the variable can be manipulated arbitrarily. */ |
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60 | +#define OPTIMIZER_HIDE_VAR(var) \ |
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61 | + __asm__ ("" : "=r" (var) : "0" (var)) |
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62 | + |
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63 | +#ifdef __CHECKER__ |
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64 | +#define __must_be_array(a) 0 |
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65 | +#else |
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66 | +/* &a[0] degrades to a pointer: a different type from an array */ |
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67 | +#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) |
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68 | +#endif |
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69 | + |
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70 | +/* |
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71 | + * Force always-inline if the user requests it so via the .config, |
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72 | + * or if gcc is too old: |
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73 | + */ |
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74 | +#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ |
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75 | + !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) |
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76 | +#define inline inline __attribute__((always_inline)) notrace |
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77 | +#define __inline__ __inline__ __attribute__((always_inline)) notrace |
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78 | +#define __inline __inline __attribute__((always_inline)) notrace |
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79 | +#else |
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80 | +/* A lot of inline functions can cause havoc with function tracing */ |
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81 | +#define inline inline notrace |
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82 | +#define __inline__ __inline__ notrace |
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83 | +#define __inline __inline notrace |
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84 | +#endif |
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85 | + |
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86 | +#define __always_inline inline __attribute__((always_inline)) |
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87 | +#define noinline __attribute__((noinline)) |
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88 | + |
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89 | +#define __deprecated __attribute__((deprecated)) |
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90 | +#define __packed __attribute__((packed)) |
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91 | +#define __weak __attribute__((weak)) |
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92 | +#define __alias(symbol) __attribute__((alias(#symbol))) |
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93 | + |
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94 | +/* |
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95 | + * it doesn't make sense on ARM (currently the only user of __naked) |
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96 | + * to trace naked functions because then mcount is called without |
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97 | + * stack and frame pointer being set up and there is no chance to |
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98 | + * restore the lr register to the value before mcount was called. |
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99 | + * |
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100 | + * The asm() bodies of naked functions often depend on standard calling |
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101 | + * conventions, therefore they must be noinline and noclone. |
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102 | + * |
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103 | + * GCC 4.[56] currently fail to enforce this, so we must do so ourselves. |
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104 | + * See GCC PR44290. |
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105 | + */ |
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106 | +#define __naked __attribute__((naked)) noinline __noclone notrace |
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107 | + |
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108 | +#define __noreturn __attribute__((noreturn)) |
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109 | + |
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110 | +/* |
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111 | + * From the GCC manual: |
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112 | + * |
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113 | + * Many functions have no effects except the return value and their |
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114 | + * return value depends only on the parameters and/or global |
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115 | + * variables. Such a function can be subject to common subexpression |
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116 | + * elimination and loop optimization just as an arithmetic operator |
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117 | + * would be. |
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118 | + * [...] |
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119 | + */ |
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120 | +#define __pure __attribute__((pure)) |
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121 | +#define __aligned(x) __attribute__((aligned(x))) |
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122 | +#define __printf(a, b) __attribute__((format(printf, a, b))) |
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123 | +#define __scanf(a, b) __attribute__((format(scanf, a, b))) |
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124 | +#define __attribute_const__ __attribute__((__const__)) |
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125 | +#define __maybe_unused __attribute__((unused)) |
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126 | +#define __always_unused __attribute__((unused)) |
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127 | + |
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128 | +/* gcc version specific checks */ |
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129 | + |
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130 | +#if GCC_VERSION < 30200 |
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131 | +# error Sorry, your compiler is too old - please upgrade it. |
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132 | +#endif |
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133 | + |
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134 | +#if GCC_VERSION < 30300 |
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135 | +# define __used __attribute__((__unused__)) |
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136 | +#else |
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137 | +# define __used __attribute__((__used__)) |
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138 | +#endif |
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139 | + |
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140 | +#ifdef CONFIG_GCOV_KERNEL |
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141 | +# if GCC_VERSION < 30400 |
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142 | +# error "GCOV profiling support for gcc versions below 3.4 not included" |
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143 | +# endif /* __GNUC_MINOR__ */ |
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144 | +#endif /* CONFIG_GCOV_KERNEL */ |
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145 | + |
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146 | +#if GCC_VERSION >= 30400 |
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147 | +#define __must_check __attribute__((warn_unused_result)) |
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148 | +#define __malloc __attribute__((__malloc__)) |
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149 | +#endif |
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150 | + |
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151 | +#if GCC_VERSION >= 40000 |
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152 | + |
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153 | +/* GCC 4.1.[01] miscompiles __weak */ |
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154 | +#ifdef __KERNEL__ |
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155 | +# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101 |
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156 | +# error Your version of gcc miscompiles the __weak directive |
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157 | +# endif |
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158 | +#endif |
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159 | + |
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160 | +#define __used __attribute__((__used__)) |
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161 | +#define __compiler_offsetof(a, b) \ |
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162 | + __builtin_offsetof(a, b) |
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163 | + |
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164 | +#if GCC_VERSION >= 40100 && GCC_VERSION < 40600 |
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165 | +# define __compiletime_object_size(obj) __builtin_object_size(obj, 0) |
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166 | +#endif |
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167 | + |
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168 | +#if GCC_VERSION >= 40300 |
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169 | +/* Mark functions as cold. gcc will assume any path leading to a call |
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170 | + * to them will be unlikely. This means a lot of manual unlikely()s |
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171 | + * are unnecessary now for any paths leading to the usual suspects |
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172 | + * like BUG(), printk(), panic() etc. [but let's keep them for now for |
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173 | + * older compilers] |
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174 | + * |
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175 | + * Early snapshots of gcc 4.3 don't support this and we can't detect this |
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176 | + * in the preprocessor, but we can live with this because they're unreleased. |
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177 | + * Maketime probing would be overkill here. |
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178 | + * |
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179 | + * gcc also has a __attribute__((__hot__)) to move hot functions into |
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180 | + * a special section, but I don't see any sense in this right now in |
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181 | + * the kernel context |
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182 | + */ |
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183 | +#define __cold __attribute__((__cold__)) |
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184 | + |
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185 | +#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) |
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186 | + |
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187 | +#ifndef __CHECKER__ |
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188 | +# define __compiletime_warning(message) __attribute__((warning(message))) |
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189 | +# define __compiletime_error(message) __attribute__((error(message))) |
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190 | +#endif /* __CHECKER__ */ |
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191 | +#endif /* GCC_VERSION >= 40300 */ |
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192 | + |
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193 | +#if GCC_VERSION >= 40500 |
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194 | +/* |
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195 | + * Mark a position in code as unreachable. This can be used to |
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196 | + * suppress control flow warnings after asm blocks that transfer |
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197 | + * control elsewhere. |
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198 | + * |
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199 | + * Early snapshots of gcc 4.5 don't support this and we can't detect |
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200 | + * this in the preprocessor, but we can live with this because they're |
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201 | + * unreleased. Really, we need to have autoconf for the kernel. |
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202 | + */ |
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203 | +#define unreachable() __builtin_unreachable() |
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204 | + |
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205 | +/* Mark a function definition as prohibited from being cloned. */ |
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206 | +#define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) |
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207 | + |
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208 | +#endif /* GCC_VERSION >= 40500 */ |
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209 | + |
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210 | +#if GCC_VERSION >= 40600 |
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211 | +/* |
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212 | + * When used with Link Time Optimization, gcc can optimize away C functions or |
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213 | + * variables which are referenced only from assembly code. __visible tells the |
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214 | + * optimizer that something else uses this function or variable, thus preventing |
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215 | + * this. |
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216 | + */ |
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217 | +#define __visible __attribute__((externally_visible)) |
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218 | +#endif |
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219 | + |
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220 | + |
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221 | +#if GCC_VERSION >= 40900 && !defined(__CHECKER__) |
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222 | +/* |
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223 | + * __assume_aligned(n, k): Tell the optimizer that the returned |
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224 | + * pointer can be assumed to be k modulo n. The second argument is |
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225 | + * optional (default 0), so we use a variadic macro to make the |
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226 | + * shorthand. |
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227 | + * |
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228 | + * Beware: Do not apply this to functions which may return |
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229 | + * ERR_PTRs. Also, it is probably unwise to apply it to functions |
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230 | + * returning extra information in the low bits (but in that case the |
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231 | + * compiler should see some alignment anyway, when the return value is |
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232 | + * massaged by 'flags = ptr & 3; ptr &= ~3;'). |
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233 | + */ |
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234 | +#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) |
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235 | +#endif |
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236 | + |
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237 | +/* |
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238 | + * GCC 'asm goto' miscompiles certain code sequences: |
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239 | + * |
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240 | + * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 |
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241 | + * |
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242 | + * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. |
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243 | + * |
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244 | + * (asm goto is automatically volatile - the naming reflects this.) |
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245 | + */ |
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246 | +#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) |
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247 | + |
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248 | +#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP |
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249 | +#if GCC_VERSION >= 40400 |
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250 | +#define __HAVE_BUILTIN_BSWAP32__ |
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251 | +#define __HAVE_BUILTIN_BSWAP64__ |
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252 | +#endif |
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253 | +#if GCC_VERSION >= 40800 |
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254 | +#define __HAVE_BUILTIN_BSWAP16__ |
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255 | +#endif |
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256 | +#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ |
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257 | + |
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258 | +#if GCC_VERSION >= 50000 |
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259 | +#define KASAN_ABI_VERSION 4 |
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260 | +#elif GCC_VERSION >= 40902 |
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261 | +#define KASAN_ABI_VERSION 3 |
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262 | +#endif |
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263 | + |
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264 | +#if GCC_VERSION >= 40902 |
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265 | +/* |
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266 | + * Tell the compiler that address safety instrumentation (KASAN) |
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267 | + * should not be applied to that function. |
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268 | + * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 |
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269 | + */ |
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270 | +#define __no_sanitize_address __attribute__((no_sanitize_address)) |
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271 | +#endif |
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272 | + |
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273 | +#endif /* gcc version >= 40000 specific checks */ |
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274 | + |
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275 | +#if !defined(__noclone) |
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276 | +#define __noclone /* not needed */ |
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277 | +#endif |
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278 | + |
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279 | +#if !defined(__no_sanitize_address) |
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280 | +#define __no_sanitize_address |
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281 | +#endif |
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282 | + |
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283 | +/* |
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284 | + * A trick to suppress uninitialized variable warning without generating any |
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285 | + * code |
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286 | + */ |
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287 | +#define uninitialized_var(x) x = x |