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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
d1515582 | 2 | #ifndef __LINUX_COMPILER_TYPES_H |
94f582f8 RD |
3 | #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead." |
4 | #endif | |
1da177e4 LT |
5 | |
6 | /* | |
7 | * Common definitions for all gcc versions go here. | |
8 | */ | |
f6d133f8 JP |
9 | #define GCC_VERSION (__GNUC__ * 10000 \ |
10 | + __GNUC_MINOR__ * 100 \ | |
11 | + __GNUC_PATCHLEVEL__) | |
1da177e4 | 12 | |
1da177e4 | 13 | /* Optimization barrier */ |
7829fb09 | 14 | |
1da177e4 LT |
15 | /* The "volatile" is due to gcc bugs */ |
16 | #define barrier() __asm__ __volatile__("": : :"memory") | |
7829fb09 DB |
17 | /* |
18 | * This version is i.e. to prevent dead stores elimination on @ptr | |
19 | * where gcc and llvm may behave differently when otherwise using | |
20 | * normal barrier(): while gcc behavior gets along with a normal | |
21 | * barrier(), llvm needs an explicit input variable to be assumed | |
22 | * clobbered. The issue is as follows: while the inline asm might | |
23 | * access any memory it wants, the compiler could have fit all of | |
24 | * @ptr into memory registers instead, and since @ptr never escaped | |
8e8780a5 | 25 | * from that, it proved that the inline asm wasn't touching any of |
7829fb09 DB |
26 | * it. This version works well with both compilers, i.e. we're telling |
27 | * the compiler that the inline asm absolutely may see the contents | |
28 | * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 | |
29 | */ | |
30 | #define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") | |
1da177e4 | 31 | |
c8d52465 | 32 | /* |
85c210ed AK |
33 | * This macro obfuscates arithmetic on a variable address so that gcc |
34 | * shouldn't recognize the original var, and make assumptions about it. | |
35 | * | |
36 | * This is needed because the C standard makes it undefined to do | |
37 | * pointer arithmetic on "objects" outside their boundaries and the | |
38 | * gcc optimizers assume this is the case. In particular they | |
39 | * assume such arithmetic does not wrap. | |
40 | * | |
41 | * A miscompilation has been observed because of this on PPC. | |
42 | * To work around it we hide the relationship of the pointer and the object | |
43 | * using this macro. | |
44 | * | |
c8d52465 AB |
45 | * Versions of the ppc64 compiler before 4.1 had a bug where use of |
46 | * RELOC_HIDE could trash r30. The bug can be worked around by changing | |
47 | * the inline assembly constraint from =g to =r, in this particular | |
48 | * case either is valid. | |
49 | */ | |
f6d133f8 JP |
50 | #define RELOC_HIDE(ptr, off) \ |
51 | ({ \ | |
52 | unsigned long __ptr; \ | |
53 | __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ | |
54 | (typeof(ptr)) (__ptr + (off)); \ | |
55 | }) | |
a1365647 | 56 | |
fe8c8a12 | 57 | /* Make the optimizer believe the variable can be manipulated arbitrarily. */ |
f6d133f8 JP |
58 | #define OPTIMIZER_HIDE_VAR(var) \ |
59 | __asm__ ("" : "=r" (var) : "0" (var)) | |
fe8c8a12 | 60 | |
5bd7e6a3 | 61 | #ifdef __CHECKER__ |
f6d133f8 | 62 | #define __must_be_array(a) 0 |
5bd7e6a3 | 63 | #else |
c5e631cf | 64 | /* &a[0] degrades to a pointer: a different type from an array */ |
f6d133f8 | 65 | #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) |
5bd7e6a3 | 66 | #endif |
a1365647 | 67 | |
60a3cdd0 | 68 | /* |
ae3a0064 | 69 | * Force always-inline if the user requests it so via the .config, |
9a04dbcf DR |
70 | * or if gcc is too old. |
71 | * GCC does not warn about unused static inline functions for | |
72 | * -Wunused-function. This turns out to avoid the need for complex #ifdef | |
73 | * directives. Suppress the warning in clang as well by using "unused" | |
74 | * function attribute, which is redundant but not harmful for gcc. | |
60a3cdd0 | 75 | */ |
f6d133f8 | 76 | #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ |
ae3a0064 | 77 | !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) |
9a04dbcf DR |
78 | #define inline inline __attribute__((always_inline,unused)) notrace |
79 | #define __inline__ __inline__ __attribute__((always_inline,unused)) notrace | |
80 | #define __inline __inline __attribute__((always_inline,unused)) notrace | |
45959ee7 SR |
81 | #else |
82 | /* A lot of inline functions can cause havoc with function tracing */ | |
9a04dbcf DR |
83 | #define inline inline __attribute__((unused)) notrace |
84 | #define __inline__ __inline__ __attribute__((unused)) notrace | |
85 | #define __inline __inline __attribute__((unused)) notrace | |
60a3cdd0 IM |
86 | #endif |
87 | ||
f6d133f8 JP |
88 | #define __always_inline inline __attribute__((always_inline)) |
89 | #define noinline __attribute__((noinline)) | |
90 | ||
91 | #define __deprecated __attribute__((deprecated)) | |
92 | #define __packed __attribute__((packed)) | |
93 | #define __weak __attribute__((weak)) | |
94 | #define __alias(symbol) __attribute__((alias(#symbol))) | |
446c92b2 UKK |
95 | |
96 | /* | |
f6d133f8 JP |
97 | * it doesn't make sense on ARM (currently the only user of __naked) |
98 | * to trace naked functions because then mcount is called without | |
99 | * stack and frame pointer being set up and there is no chance to | |
100 | * restore the lr register to the value before mcount was called. | |
101 | * | |
102 | * The asm() bodies of naked functions often depend on standard calling | |
103 | * conventions, therefore they must be noinline and noclone. | |
9c695203 | 104 | * |
f6d133f8 JP |
105 | * GCC 4.[56] currently fail to enforce this, so we must do so ourselves. |
106 | * See GCC PR44290. | |
446c92b2 | 107 | */ |
f6d133f8 | 108 | #define __naked __attribute__((naked)) noinline __noclone notrace |
446c92b2 | 109 | |
f6d133f8 | 110 | #define __noreturn __attribute__((noreturn)) |
e8c44319 RB |
111 | |
112 | /* | |
113 | * From the GCC manual: | |
114 | * | |
115 | * Many functions have no effects except the return value and their | |
116 | * return value depends only on the parameters and/or global | |
117 | * variables. Such a function can be subject to common subexpression | |
118 | * elimination and loop optimization just as an arithmetic operator | |
119 | * would be. | |
120 | * [...] | |
121 | */ | |
f6d133f8 JP |
122 | #define __pure __attribute__((pure)) |
123 | #define __aligned(x) __attribute__((aligned(x))) | |
d8c34b94 | 124 | #define __aligned_largest __attribute__((aligned)) |
f6d133f8 JP |
125 | #define __printf(a, b) __attribute__((format(printf, a, b))) |
126 | #define __scanf(a, b) __attribute__((format(scanf, a, b))) | |
127 | #define __attribute_const__ __attribute__((__const__)) | |
128 | #define __maybe_unused __attribute__((unused)) | |
129 | #define __always_unused __attribute__((unused)) | |
a3f0825e | 130 | #define __mode(x) __attribute__((mode(x))) |
f153b821 | 131 | |
cb984d10 JP |
132 | /* gcc version specific checks */ |
133 | ||
134 | #if GCC_VERSION < 30200 | |
135 | # error Sorry, your compiler is too old - please upgrade it. | |
136 | #endif | |
137 | ||
138 | #if GCC_VERSION < 30300 | |
139 | # define __used __attribute__((__unused__)) | |
140 | #else | |
141 | # define __used __attribute__((__used__)) | |
142 | #endif | |
143 | ||
144 | #ifdef CONFIG_GCOV_KERNEL | |
145 | # if GCC_VERSION < 30400 | |
146 | # error "GCOV profiling support for gcc versions below 3.4 not included" | |
147 | # endif /* __GNUC_MINOR__ */ | |
148 | #endif /* CONFIG_GCOV_KERNEL */ | |
149 | ||
150 | #if GCC_VERSION >= 30400 | |
151 | #define __must_check __attribute__((warn_unused_result)) | |
d64e85d3 | 152 | #define __malloc __attribute__((__malloc__)) |
cb984d10 JP |
153 | #endif |
154 | ||
155 | #if GCC_VERSION >= 40000 | |
156 | ||
157 | /* GCC 4.1.[01] miscompiles __weak */ | |
158 | #ifdef __KERNEL__ | |
159 | # if GCC_VERSION >= 40100 && GCC_VERSION <= 40101 | |
160 | # error Your version of gcc miscompiles the __weak directive | |
161 | # endif | |
162 | #endif | |
163 | ||
164 | #define __used __attribute__((__used__)) | |
165 | #define __compiler_offsetof(a, b) \ | |
166 | __builtin_offsetof(a, b) | |
167 | ||
0d025d27 | 168 | #if GCC_VERSION >= 40100 |
cb984d10 | 169 | # define __compiletime_object_size(obj) __builtin_object_size(obj, 0) |
7375ae3a TL |
170 | |
171 | #define __nostackprotector __attribute__((__optimize__("no-stack-protector"))) | |
cb984d10 JP |
172 | #endif |
173 | ||
174 | #if GCC_VERSION >= 40300 | |
175 | /* Mark functions as cold. gcc will assume any path leading to a call | |
176 | * to them will be unlikely. This means a lot of manual unlikely()s | |
177 | * are unnecessary now for any paths leading to the usual suspects | |
178 | * like BUG(), printk(), panic() etc. [but let's keep them for now for | |
179 | * older compilers] | |
180 | * | |
181 | * Early snapshots of gcc 4.3 don't support this and we can't detect this | |
182 | * in the preprocessor, but we can live with this because they're unreleased. | |
183 | * Maketime probing would be overkill here. | |
184 | * | |
185 | * gcc also has a __attribute__((__hot__)) to move hot functions into | |
186 | * a special section, but I don't see any sense in this right now in | |
187 | * the kernel context | |
188 | */ | |
189 | #define __cold __attribute__((__cold__)) | |
190 | ||
191 | #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) | |
192 | ||
193 | #ifndef __CHECKER__ | |
194 | # define __compiletime_warning(message) __attribute__((warning(message))) | |
195 | # define __compiletime_error(message) __attribute__((error(message))) | |
196 | #endif /* __CHECKER__ */ | |
197 | #endif /* GCC_VERSION >= 40300 */ | |
198 | ||
199 | #if GCC_VERSION >= 40500 | |
0766f788 ER |
200 | |
201 | #ifndef __CHECKER__ | |
202 | #ifdef LATENT_ENTROPY_PLUGIN | |
203 | #define __latent_entropy __attribute__((latent_entropy)) | |
204 | #endif | |
205 | #endif | |
206 | ||
cb984d10 JP |
207 | /* |
208 | * Mark a position in code as unreachable. This can be used to | |
209 | * suppress control flow warnings after asm blocks that transfer | |
210 | * control elsewhere. | |
211 | * | |
212 | * Early snapshots of gcc 4.5 don't support this and we can't detect | |
213 | * this in the preprocessor, but we can live with this because they're | |
214 | * unreleased. Really, we need to have autoconf for the kernel. | |
215 | */ | |
4e4636cf JP |
216 | #define unreachable() \ |
217 | do { annotate_unreachable(); __builtin_unreachable(); } while (0) | |
cb984d10 JP |
218 | |
219 | /* Mark a function definition as prohibited from being cloned. */ | |
95272c29 | 220 | #define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) |
cb984d10 | 221 | |
a3d6c976 | 222 | #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__) |
313dd1b6 KC |
223 | #define __randomize_layout __attribute__((randomize_layout)) |
224 | #define __no_randomize_layout __attribute__((no_randomize_layout)) | |
225 | #endif | |
226 | ||
cb984d10 JP |
227 | #endif /* GCC_VERSION >= 40500 */ |
228 | ||
229 | #if GCC_VERSION >= 40600 | |
29e48ce8 | 230 | |
cb984d10 | 231 | /* |
9add850c AM |
232 | * When used with Link Time Optimization, gcc can optimize away C functions or |
233 | * variables which are referenced only from assembly code. __visible tells the | |
234 | * optimizer that something else uses this function or variable, thus preventing | |
235 | * this. | |
cb984d10 JP |
236 | */ |
237 | #define __visible __attribute__((externally_visible)) | |
29e48ce8 KC |
238 | |
239 | /* | |
240 | * RANDSTRUCT_PLUGIN wants to use an anonymous struct, but it is only | |
241 | * possible since GCC 4.6. To provide as much build testing coverage | |
242 | * as possible, this is used for all GCC 4.6+ builds, and not just on | |
243 | * RANDSTRUCT_PLUGIN builds. | |
244 | */ | |
245 | #define randomized_struct_fields_start struct { | |
246 | #define randomized_struct_fields_end } __randomize_layout; | |
247 | ||
248 | #endif /* GCC_VERSION >= 40600 */ | |
cb984d10 | 249 | |
a744fd17 | 250 | |
8748dd5c | 251 | #if GCC_VERSION >= 40900 && !defined(__CHECKER__) |
a744fd17 RV |
252 | /* |
253 | * __assume_aligned(n, k): Tell the optimizer that the returned | |
254 | * pointer can be assumed to be k modulo n. The second argument is | |
255 | * optional (default 0), so we use a variadic macro to make the | |
256 | * shorthand. | |
257 | * | |
258 | * Beware: Do not apply this to functions which may return | |
259 | * ERR_PTRs. Also, it is probably unwise to apply it to functions | |
260 | * returning extra information in the low bits (but in that case the | |
261 | * compiler should see some alignment anyway, when the return value is | |
262 | * massaged by 'flags = ptr & 3; ptr &= ~3;'). | |
263 | */ | |
264 | #define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) | |
265 | #endif | |
266 | ||
cb984d10 JP |
267 | /* |
268 | * GCC 'asm goto' miscompiles certain code sequences: | |
269 | * | |
270 | * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 | |
271 | * | |
272 | * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. | |
273 | * | |
274 | * (asm goto is automatically volatile - the naming reflects this.) | |
275 | */ | |
276 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) | |
277 | ||
101b29a2 JB |
278 | /* |
279 | * sparse (__CHECKER__) pretends to be gcc, but can't do constant | |
280 | * folding in __builtin_bswap*() (yet), so don't set these for it. | |
281 | */ | |
282 | #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__) | |
cb984d10 JP |
283 | #if GCC_VERSION >= 40400 |
284 | #define __HAVE_BUILTIN_BSWAP32__ | |
285 | #define __HAVE_BUILTIN_BSWAP64__ | |
286 | #endif | |
8634de6d | 287 | #if GCC_VERSION >= 40800 |
cb984d10 JP |
288 | #define __HAVE_BUILTIN_BSWAP16__ |
289 | #endif | |
101b29a2 | 290 | #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */ |
cb984d10 | 291 | |
045d599a DV |
292 | #if GCC_VERSION >= 70000 |
293 | #define KASAN_ABI_VERSION 5 | |
294 | #elif GCC_VERSION >= 50000 | |
cb984d10 JP |
295 | #define KASAN_ABI_VERSION 4 |
296 | #elif GCC_VERSION >= 40902 | |
297 | #define KASAN_ABI_VERSION 3 | |
298 | #endif | |
299 | ||
d976441f AR |
300 | #if GCC_VERSION >= 40902 |
301 | /* | |
302 | * Tell the compiler that address safety instrumentation (KASAN) | |
303 | * should not be applied to that function. | |
304 | * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 | |
305 | */ | |
306 | #define __no_sanitize_address __attribute__((no_sanitize_address)) | |
307 | #endif | |
308 | ||
0aa5e49c KC |
309 | #if GCC_VERSION >= 50100 |
310 | /* | |
311 | * Mark structures as requiring designated initializers. | |
312 | * https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html | |
313 | */ | |
314 | #define __designated_init __attribute__((designated_init)) | |
315 | #endif | |
316 | ||
cb984d10 | 317 | #endif /* gcc version >= 40000 specific checks */ |
9c695203 MP |
318 | |
319 | #if !defined(__noclone) | |
320 | #define __noclone /* not needed */ | |
321 | #endif | |
c837fb37 | 322 | |
d976441f AR |
323 | #if !defined(__no_sanitize_address) |
324 | #define __no_sanitize_address | |
325 | #endif | |
326 | ||
c837fb37 BP |
327 | /* |
328 | * A trick to suppress uninitialized variable warning without generating any | |
329 | * code | |
330 | */ | |
331 | #define uninitialized_var(x) x = x |