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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef __LINUX_COMPILER_H |
3 | #define __LINUX_COMPILER_H | |
4 | ||
d1515582 | 5 | #include <linux/compiler_types.h> |
1da177e4 | 6 | |
d1515582 | 7 | #ifndef __ASSEMBLY__ |
6f33d587 | 8 | |
1da177e4 LT |
9 | #ifdef __KERNEL__ |
10 | ||
2ed84eeb SR |
11 | /* |
12 | * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code | |
13 | * to disable branch tracing on a per file basis. | |
14 | */ | |
d9ad8bc0 BVA |
15 | #if defined(CONFIG_TRACE_BRANCH_PROFILING) \ |
16 | && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__) | |
134e6a03 | 17 | void ftrace_likely_update(struct ftrace_likely_data *f, int val, |
d45ae1f7 | 18 | int expect, int is_constant); |
1f0d69a9 SR |
19 | |
20 | #define likely_notrace(x) __builtin_expect(!!(x), 1) | |
21 | #define unlikely_notrace(x) __builtin_expect(!!(x), 0) | |
22 | ||
d45ae1f7 | 23 | #define __branch_check__(x, expect, is_constant) ({ \ |
2026d357 | 24 | long ______r; \ |
134e6a03 | 25 | static struct ftrace_likely_data \ |
e04462fb MO |
26 | __aligned(4) \ |
27 | __section("_ftrace_annotated_branch") \ | |
1f0d69a9 | 28 | ______f = { \ |
134e6a03 SRV |
29 | .data.func = __func__, \ |
30 | .data.file = __FILE__, \ | |
31 | .data.line = __LINE__, \ | |
1f0d69a9 | 32 | }; \ |
d45ae1f7 SRV |
33 | ______r = __builtin_expect(!!(x), expect); \ |
34 | ftrace_likely_update(&______f, ______r, \ | |
35 | expect, is_constant); \ | |
1f0d69a9 SR |
36 | ______r; \ |
37 | }) | |
38 | ||
39 | /* | |
40 | * Using __builtin_constant_p(x) to ignore cases where the return | |
41 | * value is always the same. This idea is taken from a similar patch | |
42 | * written by Daniel Walker. | |
43 | */ | |
44 | # ifndef likely | |
d45ae1f7 | 45 | # define likely(x) (__branch_check__(x, 1, __builtin_constant_p(x))) |
1f0d69a9 SR |
46 | # endif |
47 | # ifndef unlikely | |
d45ae1f7 | 48 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) |
1f0d69a9 | 49 | # endif |
2bcd521a SR |
50 | |
51 | #ifdef CONFIG_PROFILE_ALL_BRANCHES | |
52 | /* | |
53 | * "Define 'is'", Bill Clinton | |
54 | * "Define 'if'", Steven Rostedt | |
55 | */ | |
ab3c9c68 LT |
56 | #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) ) |
57 | #define __trace_if(cond) \ | |
b33c8ff4 | 58 | if (__builtin_constant_p(!!(cond)) ? !!(cond) : \ |
2bcd521a SR |
59 | ({ \ |
60 | int ______r; \ | |
61 | static struct ftrace_branch_data \ | |
e04462fb MO |
62 | __aligned(4) \ |
63 | __section("_ftrace_branch") \ | |
2bcd521a SR |
64 | ______f = { \ |
65 | .func = __func__, \ | |
66 | .file = __FILE__, \ | |
67 | .line = __LINE__, \ | |
68 | }; \ | |
69 | ______r = !!(cond); \ | |
97e7e4f3 | 70 | ______f.miss_hit[______r]++; \ |
2bcd521a SR |
71 | ______r; \ |
72 | })) | |
73 | #endif /* CONFIG_PROFILE_ALL_BRANCHES */ | |
74 | ||
1f0d69a9 SR |
75 | #else |
76 | # define likely(x) __builtin_expect(!!(x), 1) | |
77 | # define unlikely(x) __builtin_expect(!!(x), 0) | |
78 | #endif | |
1da177e4 LT |
79 | |
80 | /* Optimization barrier */ | |
81 | #ifndef barrier | |
82 | # define barrier() __memory_barrier() | |
83 | #endif | |
84 | ||
7829fb09 DB |
85 | #ifndef barrier_data |
86 | # define barrier_data(ptr) barrier() | |
87 | #endif | |
88 | ||
173a3efd AB |
89 | /* workaround for GCC PR82365 if needed */ |
90 | #ifndef barrier_before_unreachable | |
91 | # define barrier_before_unreachable() do { } while (0) | |
92 | #endif | |
93 | ||
38938c87 | 94 | /* Unreachable code */ |
649ea4d5 | 95 | #ifdef CONFIG_STACK_VALIDATION |
d0c2e691 JP |
96 | /* |
97 | * These macros help objtool understand GCC code flow for unreachable code. | |
98 | * The __COUNTER__ based labels are a hack to make each instance of the macros | |
99 | * unique, to convince GCC not to merge duplicate inline asm statements. | |
100 | */ | |
649ea4d5 | 101 | #define annotate_reachable() ({ \ |
c06c4d80 NA |
102 | asm volatile("ANNOTATE_REACHABLE counter=%c0" \ |
103 | : : "i" (__COUNTER__)); \ | |
649ea4d5 JP |
104 | }) |
105 | #define annotate_unreachable() ({ \ | |
c06c4d80 NA |
106 | asm volatile("ANNOTATE_UNREACHABLE counter=%c0" \ |
107 | : : "i" (__COUNTER__)); \ | |
649ea4d5 | 108 | }) |
649ea4d5 JP |
109 | #else |
110 | #define annotate_reachable() | |
111 | #define annotate_unreachable() | |
112 | #endif | |
113 | ||
aa5d1b81 KC |
114 | #ifndef ASM_UNREACHABLE |
115 | # define ASM_UNREACHABLE | |
116 | #endif | |
38938c87 | 117 | #ifndef unreachable |
fe0640eb | 118 | # define unreachable() do { \ |
119 | annotate_unreachable(); \ | |
120 | __builtin_unreachable(); \ | |
121 | } while (0) | |
38938c87 DD |
122 | #endif |
123 | ||
b67067f1 NP |
124 | /* |
125 | * KENTRY - kernel entry point | |
126 | * This can be used to annotate symbols (functions or data) that are used | |
127 | * without their linker symbol being referenced explicitly. For example, | |
128 | * interrupt vector handlers, or functions in the kernel image that are found | |
129 | * programatically. | |
130 | * | |
131 | * Not required for symbols exported with EXPORT_SYMBOL, or initcalls. Those | |
132 | * are handled in their own way (with KEEP() in linker scripts). | |
133 | * | |
134 | * KENTRY can be avoided if the symbols in question are marked as KEEP() in the | |
135 | * linker script. For example an architecture could KEEP() its entire | |
136 | * boot/exception vector code rather than annotate each function and data. | |
137 | */ | |
138 | #ifndef KENTRY | |
139 | # define KENTRY(sym) \ | |
140 | extern typeof(sym) sym; \ | |
141 | static const unsigned long __kentry_##sym \ | |
142 | __used \ | |
e04462fb | 143 | __section("___kentry" "+" #sym ) \ |
b67067f1 NP |
144 | = (unsigned long)&sym; |
145 | #endif | |
146 | ||
1da177e4 LT |
147 | #ifndef RELOC_HIDE |
148 | # define RELOC_HIDE(ptr, off) \ | |
149 | ({ unsigned long __ptr; \ | |
150 | __ptr = (unsigned long) (ptr); \ | |
151 | (typeof(ptr)) (__ptr + (off)); }) | |
152 | #endif | |
153 | ||
fe8c8a12 CEB |
154 | #ifndef OPTIMIZER_HIDE_VAR |
155 | #define OPTIMIZER_HIDE_VAR(var) barrier() | |
156 | #endif | |
157 | ||
6f33d587 RR |
158 | /* Not-quite-unique ID. */ |
159 | #ifndef __UNIQUE_ID | |
160 | # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__) | |
161 | #endif | |
162 | ||
230fa253 CB |
163 | #include <uapi/linux/types.h> |
164 | ||
d976441f AR |
165 | #define __READ_ONCE_SIZE \ |
166 | ({ \ | |
167 | switch (size) { \ | |
168 | case 1: *(__u8 *)res = *(volatile __u8 *)p; break; \ | |
169 | case 2: *(__u16 *)res = *(volatile __u16 *)p; break; \ | |
170 | case 4: *(__u32 *)res = *(volatile __u32 *)p; break; \ | |
171 | case 8: *(__u64 *)res = *(volatile __u64 *)p; break; \ | |
172 | default: \ | |
173 | barrier(); \ | |
174 | __builtin_memcpy((void *)res, (const void *)p, size); \ | |
175 | barrier(); \ | |
176 | } \ | |
177 | }) | |
178 | ||
179 | static __always_inline | |
180 | void __read_once_size(const volatile void *p, void *res, int size) | |
230fa253 | 181 | { |
d976441f AR |
182 | __READ_ONCE_SIZE; |
183 | } | |
184 | ||
185 | #ifdef CONFIG_KASAN | |
186 | /* | |
bdb5ac80 | 187 | * We can't declare function 'inline' because __no_sanitize_address confilcts |
d976441f AR |
188 | * with inlining. Attempt to inline it may cause a build failure. |
189 | * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 | |
190 | * '__maybe_unused' allows us to avoid defined-but-not-used warnings. | |
191 | */ | |
163c8d54 | 192 | # define __no_kasan_or_inline __no_sanitize_address notrace __maybe_unused |
d976441f | 193 | #else |
bdb5ac80 AR |
194 | # define __no_kasan_or_inline __always_inline |
195 | #endif | |
196 | ||
197 | static __no_kasan_or_inline | |
d976441f AR |
198 | void __read_once_size_nocheck(const volatile void *p, void *res, int size) |
199 | { | |
200 | __READ_ONCE_SIZE; | |
230fa253 CB |
201 | } |
202 | ||
43239cbe | 203 | static __always_inline void __write_once_size(volatile void *p, void *res, int size) |
230fa253 CB |
204 | { |
205 | switch (size) { | |
206 | case 1: *(volatile __u8 *)p = *(__u8 *)res; break; | |
207 | case 2: *(volatile __u16 *)p = *(__u16 *)res; break; | |
208 | case 4: *(volatile __u32 *)p = *(__u32 *)res; break; | |
230fa253 | 209 | case 8: *(volatile __u64 *)p = *(__u64 *)res; break; |
230fa253 CB |
210 | default: |
211 | barrier(); | |
212 | __builtin_memcpy((void *)p, (const void *)res, size); | |
230fa253 CB |
213 | barrier(); |
214 | } | |
215 | } | |
216 | ||
217 | /* | |
218 | * Prevent the compiler from merging or refetching reads or writes. The | |
219 | * compiler is also forbidden from reordering successive instances of | |
b899a850 MR |
220 | * READ_ONCE and WRITE_ONCE, but only when the compiler is aware of some |
221 | * particular ordering. One way to make the compiler aware of ordering is to | |
222 | * put the two invocations of READ_ONCE or WRITE_ONCE in different C | |
223 | * statements. | |
230fa253 | 224 | * |
b899a850 MR |
225 | * These two macros will also work on aggregate data types like structs or |
226 | * unions. If the size of the accessed data type exceeds the word size of | |
227 | * the machine (e.g., 32 bits or 64 bits) READ_ONCE() and WRITE_ONCE() will | |
228 | * fall back to memcpy(). There's at least two memcpy()s: one for the | |
229 | * __builtin_memcpy() and then one for the macro doing the copy of variable | |
230 | * - '__u' allocated on the stack. | |
230fa253 CB |
231 | * |
232 | * Their two major use cases are: (1) Mediating communication between | |
233 | * process-level code and irq/NMI handlers, all running on the same CPU, | |
b899a850 | 234 | * and (2) Ensuring that the compiler does not fold, spindle, or otherwise |
230fa253 CB |
235 | * mutilate accesses that either do not require ordering or that interact |
236 | * with an explicit memory barrier or atomic instruction that provides the | |
237 | * required ordering. | |
238 | */ | |
d1515582 | 239 | #include <asm/barrier.h> |
7f1e541f | 240 | #include <linux/kasan-checks.h> |
230fa253 | 241 | |
d976441f AR |
242 | #define __READ_ONCE(x, check) \ |
243 | ({ \ | |
244 | union { typeof(x) __val; char __c[1]; } __u; \ | |
245 | if (check) \ | |
246 | __read_once_size(&(x), __u.__c, sizeof(x)); \ | |
247 | else \ | |
248 | __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ | |
76ebbe78 | 249 | smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ |
d976441f AR |
250 | __u.__val; \ |
251 | }) | |
252 | #define READ_ONCE(x) __READ_ONCE(x, 1) | |
253 | ||
254 | /* | |
255 | * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need | |
256 | * to hide memory access from KASAN. | |
257 | */ | |
258 | #define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0) | |
230fa253 | 259 | |
7f1e541f AR |
260 | static __no_kasan_or_inline |
261 | unsigned long read_word_at_a_time(const void *addr) | |
262 | { | |
263 | kasan_check_read(addr, 1); | |
264 | return *(unsigned long *)addr; | |
265 | } | |
266 | ||
43239cbe | 267 | #define WRITE_ONCE(x, val) \ |
ba33034f CB |
268 | ({ \ |
269 | union { typeof(x) __val; char __c[1]; } __u = \ | |
270 | { .__val = (__force typeof(x)) (val) }; \ | |
271 | __write_once_size(&(x), __u.__c, sizeof(x)); \ | |
272 | __u.__val; \ | |
273 | }) | |
230fa253 | 274 | |
1da177e4 LT |
275 | #endif /* __KERNEL__ */ |
276 | ||
7290d580 AB |
277 | /* |
278 | * Force the compiler to emit 'sym' as a symbol, so that we can reference | |
279 | * it from inline assembler. Necessary in case 'sym' could be inlined | |
280 | * otherwise, or eliminated entirely due to lack of references that are | |
281 | * visible to the compiler. | |
282 | */ | |
283 | #define __ADDRESSABLE(sym) \ | |
e04462fb | 284 | static void * __section(".discard.addressable") __used \ |
7290d580 AB |
285 | __PASTE(__addressable_##sym, __LINE__) = (void *)&sym; |
286 | ||
287 | /** | |
288 | * offset_to_ptr - convert a relative memory offset to an absolute pointer | |
289 | * @off: the address of the 32-bit offset value | |
290 | */ | |
291 | static inline void *offset_to_ptr(const int *off) | |
292 | { | |
293 | return (void *)((unsigned long)off + *off); | |
294 | } | |
295 | ||
c06c4d80 NA |
296 | #else /* __ASSEMBLY__ */ |
297 | ||
298 | #ifdef __KERNEL__ | |
299 | #ifndef LINKER_SCRIPT | |
300 | ||
301 | #ifdef CONFIG_STACK_VALIDATION | |
302 | .macro ANNOTATE_UNREACHABLE counter:req | |
303 | \counter: | |
304 | .pushsection .discard.unreachable | |
305 | .long \counter\()b -. | |
306 | .popsection | |
307 | .endm | |
308 | ||
309 | .macro ANNOTATE_REACHABLE counter:req | |
310 | \counter: | |
311 | .pushsection .discard.reachable | |
312 | .long \counter\()b -. | |
313 | .popsection | |
314 | .endm | |
315 | ||
316 | .macro ASM_UNREACHABLE | |
317 | 999: | |
318 | .pushsection .discard.unreachable | |
319 | .long 999b - . | |
320 | .popsection | |
321 | .endm | |
322 | #else /* CONFIG_STACK_VALIDATION */ | |
323 | .macro ANNOTATE_UNREACHABLE counter:req | |
324 | .endm | |
325 | ||
326 | .macro ANNOTATE_REACHABLE counter:req | |
327 | .endm | |
328 | ||
329 | .macro ASM_UNREACHABLE | |
330 | .endm | |
331 | #endif /* CONFIG_STACK_VALIDATION */ | |
332 | ||
333 | #endif /* LINKER_SCRIPT */ | |
334 | #endif /* __KERNEL__ */ | |
1da177e4 LT |
335 | #endif /* __ASSEMBLY__ */ |
336 | ||
9f0cf4ad AV |
337 | /* Compile time object size, -1 for unknown */ |
338 | #ifndef __compiletime_object_size | |
339 | # define __compiletime_object_size(obj) -1 | |
340 | #endif | |
4a312769 AV |
341 | #ifndef __compiletime_warning |
342 | # define __compiletime_warning(message) | |
343 | #endif | |
63312b6a AV |
344 | #ifndef __compiletime_error |
345 | # define __compiletime_error(message) | |
346 | #endif | |
c361d3e5 | 347 | |
c03567a8 JS |
348 | #ifdef __OPTIMIZE__ |
349 | # define __compiletime_assert(condition, msg, prefix, suffix) \ | |
9a8ab1c3 | 350 | do { \ |
9a8ab1c3 | 351 | extern void prefix ## suffix(void) __compiletime_error(msg); \ |
81b45683 | 352 | if (!(condition)) \ |
9a8ab1c3 | 353 | prefix ## suffix(); \ |
9a8ab1c3 | 354 | } while (0) |
c03567a8 JS |
355 | #else |
356 | # define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0) | |
357 | #endif | |
9a8ab1c3 DS |
358 | |
359 | #define _compiletime_assert(condition, msg, prefix, suffix) \ | |
360 | __compiletime_assert(condition, msg, prefix, suffix) | |
361 | ||
362 | /** | |
363 | * compiletime_assert - break build and emit msg if condition is false | |
364 | * @condition: a compile-time constant condition to check | |
365 | * @msg: a message to emit if condition is false | |
366 | * | |
367 | * In tradition of POSIX assert, this macro will break the build if the | |
368 | * supplied condition is *false*, emitting the supplied error message if the | |
369 | * compiler has support to do so. | |
370 | */ | |
371 | #define compiletime_assert(condition, msg) \ | |
372 | _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) | |
373 | ||
47933ad4 PZ |
374 | #define compiletime_assert_atomic_type(t) \ |
375 | compiletime_assert(__native_word(t), \ | |
376 | "Need native word sized stores/loads for atomicity.") | |
377 | ||
ec0bbef6 MO |
378 | /* &a[0] degrades to a pointer: a different type from an array */ |
379 | #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) | |
ec0bbef6 | 380 | |
1da177e4 | 381 | #endif /* __LINUX_COMPILER_H */ |