1 /* SPDX-License-Identifier: GPL-2.0 */ !! 1 #ifndef __LINUX_COMPILER_H
2 #ifndef __LINUX_COMPILER_TYPES_H <<
3 #error "Please don't include <linux/compiler-g 2 #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
4 #endif 3 #endif
5 4
6 /* 5 /*
7 * Common definitions for all gcc versions go 6 * Common definitions for all gcc versions go here.
8 */ 7 */
9 #define GCC_VERSION (__GNUC__ * 10000 8 #define GCC_VERSION (__GNUC__ * 10000 \
10 + __GNUC_MINOR__ * 100 9 + __GNUC_MINOR__ * 100 \
11 + __GNUC_PATCHLEVEL__) 10 + __GNUC_PATCHLEVEL__)
12 11
>> 12 /* Optimization barrier */
>> 13
>> 14 /* The "volatile" is due to gcc bugs */
>> 15 #define barrier() __asm__ __volatile__("": : :"memory")
>> 16 /*
>> 17 * This version is i.e. to prevent dead stores elimination on @ptr
>> 18 * where gcc and llvm may behave differently when otherwise using
>> 19 * normal barrier(): while gcc behavior gets along with a normal
>> 20 * barrier(), llvm needs an explicit input variable to be assumed
>> 21 * clobbered. The issue is as follows: while the inline asm might
>> 22 * access any memory it wants, the compiler could have fit all of
>> 23 * @ptr into memory registers instead, and since @ptr never escaped
>> 24 * from that, it proofed that the inline asm wasn't touching any of
>> 25 * it. This version works well with both compilers, i.e. we're telling
>> 26 * the compiler that the inline asm absolutely may see the contents
>> 27 * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
>> 28 */
>> 29 #define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
>> 30
13 /* 31 /*
14 * This macro obfuscates arithmetic on a varia 32 * This macro obfuscates arithmetic on a variable address so that gcc
15 * shouldn't recognize the original var, and m 33 * shouldn't recognize the original var, and make assumptions about it.
16 * 34 *
17 * This is needed because the C standard makes 35 * This is needed because the C standard makes it undefined to do
18 * pointer arithmetic on "objects" outside the 36 * pointer arithmetic on "objects" outside their boundaries and the
19 * gcc optimizers assume this is the case. In 37 * gcc optimizers assume this is the case. In particular they
20 * assume such arithmetic does not wrap. 38 * assume such arithmetic does not wrap.
21 * 39 *
22 * A miscompilation has been observed because 40 * A miscompilation has been observed because of this on PPC.
23 * To work around it we hide the relationship 41 * To work around it we hide the relationship of the pointer and the object
24 * using this macro. 42 * using this macro.
25 * 43 *
26 * Versions of the ppc64 compiler before 4.1 h 44 * Versions of the ppc64 compiler before 4.1 had a bug where use of
27 * RELOC_HIDE could trash r30. The bug can be 45 * RELOC_HIDE could trash r30. The bug can be worked around by changing
28 * the inline assembly constraint from =g to = 46 * the inline assembly constraint from =g to =r, in this particular
29 * case either is valid. 47 * case either is valid.
30 */ 48 */
31 #define RELOC_HIDE(ptr, off) 49 #define RELOC_HIDE(ptr, off) \
32 ({ 50 ({ \
33 unsigned long __ptr; 51 unsigned long __ptr; \
34 __asm__ ("" : "=r"(__ptr) : ""(ptr)); 52 __asm__ ("" : "=r"(__ptr) : ""(ptr)); \
35 (typeof(ptr)) (__ptr + (off)); 53 (typeof(ptr)) (__ptr + (off)); \
36 }) 54 })
37 55
38 #ifdef CONFIG_MITIGATION_RETPOLINE !! 56 /* Make the optimizer believe the variable can be manipulated arbitrarily. */
39 #define __noretpoline __attribute__((__indirec !! 57 #define OPTIMIZER_HIDE_VAR(var) \
>> 58 __asm__ ("" : "=r" (var) : "" (var))
>> 59
>> 60 #ifdef __CHECKER__
>> 61 #define __must_be_array(a) 0
>> 62 #else
>> 63 /* &a[0] degrades to a pointer: a different type from an array */
>> 64 #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
>> 65 #endif
>> 66
>> 67 /*
>> 68 * Feature detection for gnu_inline (gnu89 extern inline semantics). Either
>> 69 * __GNUC_STDC_INLINE__ is defined (not using gnu89 extern inline semantics,
>> 70 * and we opt in to the gnu89 semantics), or __GNUC_STDC_INLINE__ is not
>> 71 * defined so the gnu89 semantics are the default.
>> 72 */
>> 73 #ifdef __GNUC_STDC_INLINE__
>> 74 # define __gnu_inline __attribute__((gnu_inline))
>> 75 #else
>> 76 # define __gnu_inline
40 #endif 77 #endif
41 78
42 #if defined(LATENT_ENTROPY_PLUGIN) && !defined !! 79 /*
43 #define __latent_entropy __attribute__((latent !! 80 * Force always-inline if the user requests it so via the .config,
>> 81 * or if gcc is too old.
>> 82 * GCC does not warn about unused static inline functions for
>> 83 * -Wunused-function. This turns out to avoid the need for complex #ifdef
>> 84 * directives. Suppress the warning in clang as well by using "unused"
>> 85 * function attribute, which is redundant but not harmful for gcc.
>> 86 * Prefer gnu_inline, so that extern inline functions do not emit an
>> 87 * externally visible function. This makes extern inline behave as per gnu89
>> 88 * semantics rather than c99. This prevents multiple symbol definition errors
>> 89 * of extern inline functions at link time.
>> 90 * A lot of inline functions can cause havoc with function tracing.
>> 91 */
>> 92 #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
>> 93 !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
>> 94 #define inline \
>> 95 inline __attribute__((always_inline, unused)) notrace __gnu_inline
>> 96 #else
>> 97 #define inline inline __attribute__((unused)) notrace __gnu_inline
44 #endif 98 #endif
45 99
>> 100 #define __inline__ inline
>> 101 #define __inline inline
>> 102 #define __always_inline inline __attribute__((always_inline))
>> 103 #define noinline __attribute__((noinline))
>> 104
>> 105 #define __deprecated __attribute__((deprecated))
>> 106 #define __packed __attribute__((packed))
>> 107 #define __weak __attribute__((weak))
>> 108 #define __alias(symbol) __attribute__((alias(#symbol)))
>> 109
>> 110 /*
>> 111 * it doesn't make sense on ARM (currently the only user of __naked)
>> 112 * to trace naked functions because then mcount is called without
>> 113 * stack and frame pointer being set up and there is no chance to
>> 114 * restore the lr register to the value before mcount was called.
>> 115 *
>> 116 * The asm() bodies of naked functions often depend on standard calling
>> 117 * conventions, therefore they must be noinline and noclone.
>> 118 *
>> 119 * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
>> 120 * See GCC PR44290.
>> 121 */
>> 122 #define __naked __attribute__((naked)) noinline __noclone notrace
>> 123
>> 124 #define __noreturn __attribute__((noreturn))
>> 125
>> 126 /*
>> 127 * From the GCC manual:
>> 128 *
>> 129 * Many functions have no effects except the return value and their
>> 130 * return value depends only on the parameters and/or global
>> 131 * variables. Such a function can be subject to common subexpression
>> 132 * elimination and loop optimization just as an arithmetic operator
>> 133 * would be.
>> 134 * [...]
>> 135 */
>> 136 #define __pure __attribute__((pure))
>> 137 #define __aligned(x) __attribute__((aligned(x)))
>> 138 #define __printf(a, b) __attribute__((format(printf, a, b)))
>> 139 #define __scanf(a, b) __attribute__((format(scanf, a, b)))
>> 140 #define __attribute_const__ __attribute__((__const__))
>> 141 #define __maybe_unused __attribute__((unused))
>> 142 #define __always_unused __attribute__((unused))
>> 143
>> 144 /* gcc version specific checks */
>> 145
>> 146 #if GCC_VERSION < 30200
>> 147 # error Sorry, your compiler is too old - please upgrade it.
>> 148 #elif defined(CONFIG_ARM64) && GCC_VERSION < 50100 && !defined(__clang__)
>> 149 /*
>> 150 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
>> 151 * https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
>> 152 */
>> 153 # error Sorry, your version of GCC is too old - please use 5.1 or newer.
>> 154 #endif
>> 155
>> 156 #if GCC_VERSION < 30300
>> 157 # define __used __attribute__((__unused__))
>> 158 #else
>> 159 # define __used __attribute__((__used__))
>> 160 #endif
>> 161
>> 162 #ifdef CONFIG_GCOV_KERNEL
>> 163 # if GCC_VERSION < 30400
>> 164 # error "GCOV profiling support for gcc versions below 3.4 not included"
>> 165 # endif /* __GNUC_MINOR__ */
>> 166 #endif /* CONFIG_GCOV_KERNEL */
>> 167
>> 168 #if GCC_VERSION >= 30400
>> 169 #define __must_check __attribute__((warn_unused_result))
>> 170 #endif
>> 171
>> 172 #if GCC_VERSION >= 40000
>> 173
>> 174 /* GCC 4.1.[01] miscompiles __weak */
>> 175 #ifdef __KERNEL__
>> 176 # if GCC_VERSION >= 40100 && GCC_VERSION <= 40101
>> 177 # error Your version of gcc miscompiles the __weak directive
>> 178 # endif
>> 179 #endif
>> 180
>> 181 #define __used __attribute__((__used__))
>> 182 #define __compiler_offsetof(a, b) \
>> 183 __builtin_offsetof(a, b)
>> 184
>> 185 #if GCC_VERSION >= 40100 && GCC_VERSION < 40600
>> 186 # define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
>> 187 #endif
>> 188
>> 189 #if GCC_VERSION >= 40300
>> 190 /* Mark functions as cold. gcc will assume any path leading to a call
>> 191 * to them will be unlikely. This means a lot of manual unlikely()s
>> 192 * are unnecessary now for any paths leading to the usual suspects
>> 193 * like BUG(), printk(), panic() etc. [but let's keep them for now for
>> 194 * older compilers]
>> 195 *
>> 196 * Early snapshots of gcc 4.3 don't support this and we can't detect this
>> 197 * in the preprocessor, but we can live with this because they're unreleased.
>> 198 * Maketime probing would be overkill here.
>> 199 *
>> 200 * gcc also has a __attribute__((__hot__)) to move hot functions into
>> 201 * a special section, but I don't see any sense in this right now in
>> 202 * the kernel context
>> 203 */
>> 204 #define __cold __attribute__((__cold__))
>> 205
>> 206 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
>> 207
>> 208 #ifndef __CHECKER__
>> 209 # define __compiletime_warning(message) __attribute__((warning(message)))
>> 210 # define __compiletime_error(message) __attribute__((error(message)))
>> 211 #endif /* __CHECKER__ */
>> 212 #endif /* GCC_VERSION >= 40300 */
>> 213
>> 214 #if GCC_VERSION >= 40500
46 /* 215 /*
47 * calling noreturn functions, __builtin_unrea 216 * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
48 * confuse the stack allocation in gcc, leadin 217 * confuse the stack allocation in gcc, leading to overly large stack
49 * frames, see https://gcc.gnu.org/bugzilla/sh 218 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
50 * 219 *
51 * Adding an empty inline assembly before it w 220 * Adding an empty inline assembly before it works around the problem
52 */ 221 */
53 #define barrier_before_unreachable() asm volat 222 #define barrier_before_unreachable() asm volatile("")
54 223
55 /* 224 /*
56 * Mark a position in code as unreachable. Th 225 * Mark a position in code as unreachable. This can be used to
57 * suppress control flow warnings after asm bl 226 * suppress control flow warnings after asm blocks that transfer
58 * control elsewhere. 227 * control elsewhere.
>> 228 *
>> 229 * Early snapshots of gcc 4.5 don't support this and we can't detect
>> 230 * this in the preprocessor, but we can live with this because they're
>> 231 * unreleased. Really, we need to have autoconf for the kernel.
59 */ 232 */
60 #define unreachable() \ 233 #define unreachable() \
61 do { 234 do { \
62 annotate_unreachable(); <<
63 barrier_before_unreachable(); 235 barrier_before_unreachable(); \
64 __builtin_unreachable(); 236 __builtin_unreachable(); \
65 } while (0) 237 } while (0)
66 238
67 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) !! 239 /* Mark a function definition as prohibited from being cloned. */
68 #define __HAVE_BUILTIN_BSWAP32__ !! 240 #define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
69 #define __HAVE_BUILTIN_BSWAP64__ <<
70 #define __HAVE_BUILTIN_BSWAP16__ <<
71 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ <<
72 <<
73 #if GCC_VERSION >= 70000 <<
74 #define KASAN_ABI_VERSION 5 <<
75 #else <<
76 #define KASAN_ABI_VERSION 4 <<
77 #endif <<
78 <<
79 #ifdef CONFIG_SHADOW_CALL_STACK <<
80 #define __noscs __attribute__((__no_sanitize__ <<
81 #endif <<
82 241
83 #ifdef __SANITIZE_HWADDRESS__ !! 242 #endif /* GCC_VERSION >= 40500 */
84 #define __no_sanitize_address __attribute__((_ <<
85 #else <<
86 #define __no_sanitize_address __attribute__((_ <<
87 #endif <<
88 243
89 #if defined(__SANITIZE_THREAD__) !! 244 #if GCC_VERSION >= 40600
90 #define __no_sanitize_thread __attribute__((__ !! 245 /*
91 #else !! 246 * When used with Link Time Optimization, gcc can optimize away C functions or
92 #define __no_sanitize_thread !! 247 * variables which are referenced only from assembly code. __visible tells the
>> 248 * optimizer that something else uses this function or variable, thus preventing
>> 249 * this.
>> 250 */
>> 251 #define __visible __attribute__((externally_visible))
93 #endif 252 #endif
94 253
95 #define __no_sanitize_undefined __attribute__( <<
96 254
>> 255 #if GCC_VERSION >= 40900 && !defined(__CHECKER__)
97 /* 256 /*
98 * Only supported since gcc >= 12 !! 257 * __assume_aligned(n, k): Tell the optimizer that the returned
>> 258 * pointer can be assumed to be k modulo n. The second argument is
>> 259 * optional (default 0), so we use a variadic macro to make the
>> 260 * shorthand.
>> 261 *
>> 262 * Beware: Do not apply this to functions which may return
>> 263 * ERR_PTRs. Also, it is probably unwise to apply it to functions
>> 264 * returning extra information in the low bits (but in that case the
>> 265 * compiler should see some alignment anyway, when the return value is
>> 266 * massaged by 'flags = ptr & 3; ptr &= ~3;').
99 */ 267 */
100 #if defined(CONFIG_KCOV) && __has_attribute(__ !! 268 #define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
101 #define __no_sanitize_coverage __attribute__(( <<
102 #else <<
103 #define __no_sanitize_coverage <<
104 #endif 269 #endif
105 270
106 /* 271 /*
107 * Treat __SANITIZE_HWADDRESS__ the same as __ !! 272 * GCC 'asm goto' miscompiles certain code sequences:
108 * matching the defines used by Clang. !! 273 *
>> 274 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
>> 275 *
>> 276 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
>> 277 *
>> 278 * (asm goto is automatically volatile - the naming reflects this.)
109 */ 279 */
110 #ifdef __SANITIZE_HWADDRESS__ !! 280 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
111 #define __SANITIZE_ADDRESS__ !! 281
>> 282 #ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
>> 283 #if GCC_VERSION >= 40400
>> 284 #define __HAVE_BUILTIN_BSWAP32__
>> 285 #define __HAVE_BUILTIN_BSWAP64__
>> 286 #endif
>> 287 #if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
>> 288 #define __HAVE_BUILTIN_BSWAP16__
112 #endif 289 #endif
>> 290 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
113 291
114 /* !! 292 #if GCC_VERSION >= 70000
115 * GCC does not support KMSAN. !! 293 #define KASAN_ABI_VERSION 5
116 */ !! 294 #elif GCC_VERSION >= 50000
117 #define __no_sanitize_memory !! 295 #define KASAN_ABI_VERSION 4
118 #define __no_kmsan_checks !! 296 #elif GCC_VERSION >= 40902
>> 297 #define KASAN_ABI_VERSION 3
>> 298 #endif
119 299
>> 300 #if GCC_VERSION >= 40902
120 /* 301 /*
121 * Turn individual warnings and errors on and !! 302 * Tell the compiler that address safety instrumentation (KASAN)
122 * on version. !! 303 * should not be applied to that function.
>> 304 * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
123 */ 305 */
124 #define __diag_GCC(version, severity, s) \ !! 306 #define __no_sanitize_address __attribute__((no_sanitize_address))
125 __diag_GCC_ ## version(__diag_GCC_ ## !! 307 #endif
126 <<
127 /* Severity used in pragma directives */ <<
128 #define __diag_GCC_ignore ignored <<
129 #define __diag_GCC_warn warning <<
130 #define __diag_GCC_error error <<
131 308
132 #define __diag_str1(s) #s !! 309 #endif /* gcc version >= 40000 specific checks */
133 #define __diag_str(s) __diag_str1(s) <<
134 #define __diag(s) _Pragma(__diag <<
135 310
136 #if GCC_VERSION >= 80000 !! 311 #if !defined(__noclone)
137 #define __diag_GCC_8(s) __diag(s) !! 312 #define __noclone /* not needed */
138 #else <<
139 #define __diag_GCC_8(s) <<
140 #endif 313 #endif
141 314
142 #define __diag_ignore_all(option, comment) \ !! 315 #if !defined(__no_sanitize_address)
143 __diag(__diag_GCC_ignore option) !! 316 #define __no_sanitize_address
>> 317 #endif
144 318
145 /* 319 /*
146 * Prior to 9.1, -Wno-alloc-size-larger-than ( !! 320 * A trick to suppress uninitialized variable warning without generating any
147 * attribute) do not work, and must be disable !! 321 * code
148 */ 322 */
149 #if GCC_VERSION < 90100 !! 323 #define uninitialized_var(x) x = x
150 #undef __alloc_size__ !! 324
>> 325 #if GCC_VERSION >= 50100
>> 326 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
151 #endif 327 #endif
152 328
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