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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 | 26 | __aligned(4) \ |
bfafddd8 | 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 | */ | |
a15fd609 LT |
56 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) |
57 | ||
58 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) | |
59 | ||
60 | #define __trace_if_value(cond) ({ \ | |
61 | static struct ftrace_branch_data \ | |
62 | __aligned(4) \ | |
bfafddd8 | 63 | __section(_ftrace_branch) \ |
a15fd609 LT |
64 | __if_trace = { \ |
65 | .func = __func__, \ | |
66 | .file = __FILE__, \ | |
67 | .line = __LINE__, \ | |
68 | }; \ | |
69 | (cond) ? \ | |
70 | (__if_trace.miss_hit[1]++,1) : \ | |
71 | (__if_trace.miss_hit[0]++,0); \ | |
72 | }) | |
73 | ||
2bcd521a SR |
74 | #endif /* CONFIG_PROFILE_ALL_BRANCHES */ |
75 | ||
1f0d69a9 SR |
76 | #else |
77 | # define likely(x) __builtin_expect(!!(x), 1) | |
78 | # define unlikely(x) __builtin_expect(!!(x), 0) | |
79 | #endif | |
1da177e4 LT |
80 | |
81 | /* Optimization barrier */ | |
82 | #ifndef barrier | |
83 | # define barrier() __memory_barrier() | |
84 | #endif | |
85 | ||
7829fb09 DB |
86 | #ifndef barrier_data |
87 | # define barrier_data(ptr) barrier() | |
88 | #endif | |
89 | ||
173a3efd AB |
90 | /* workaround for GCC PR82365 if needed */ |
91 | #ifndef barrier_before_unreachable | |
92 | # define barrier_before_unreachable() do { } while (0) | |
93 | #endif | |
94 | ||
38938c87 | 95 | /* Unreachable code */ |
649ea4d5 | 96 | #ifdef CONFIG_STACK_VALIDATION |
d0c2e691 JP |
97 | /* |
98 | * These macros help objtool understand GCC code flow for unreachable code. | |
99 | * The __COUNTER__ based labels are a hack to make each instance of the macros | |
100 | * unique, to convince GCC not to merge duplicate inline asm statements. | |
101 | */ | |
649ea4d5 | 102 | #define annotate_reachable() ({ \ |
96af6cd0 IM |
103 | asm volatile("%c0:\n\t" \ |
104 | ".pushsection .discard.reachable\n\t" \ | |
105 | ".long %c0b - .\n\t" \ | |
106 | ".popsection\n\t" : : "i" (__COUNTER__)); \ | |
649ea4d5 JP |
107 | }) |
108 | #define annotate_unreachable() ({ \ | |
96af6cd0 IM |
109 | asm volatile("%c0:\n\t" \ |
110 | ".pushsection .discard.unreachable\n\t" \ | |
111 | ".long %c0b - .\n\t" \ | |
112 | ".popsection\n\t" : : "i" (__COUNTER__)); \ | |
649ea4d5 | 113 | }) |
96af6cd0 IM |
114 | #define ASM_UNREACHABLE \ |
115 | "999:\n\t" \ | |
116 | ".pushsection .discard.unreachable\n\t" \ | |
117 | ".long 999b - .\n\t" \ | |
118 | ".popsection\n\t" | |
87b512de JP |
119 | |
120 | /* Annotate a C jump table to allow objtool to follow the code flow */ | |
bfafddd8 | 121 | #define __annotate_jump_table __section(.rodata..c_jump_table) |
87b512de | 122 | |
649ea4d5 JP |
123 | #else |
124 | #define annotate_reachable() | |
125 | #define annotate_unreachable() | |
87b512de | 126 | #define __annotate_jump_table |
649ea4d5 JP |
127 | #endif |
128 | ||
aa5d1b81 KC |
129 | #ifndef ASM_UNREACHABLE |
130 | # define ASM_UNREACHABLE | |
131 | #endif | |
38938c87 | 132 | #ifndef unreachable |
fe0640eb | 133 | # define unreachable() do { \ |
134 | annotate_unreachable(); \ | |
135 | __builtin_unreachable(); \ | |
136 | } while (0) | |
38938c87 DD |
137 | #endif |
138 | ||
b67067f1 NP |
139 | /* |
140 | * KENTRY - kernel entry point | |
141 | * This can be used to annotate symbols (functions or data) that are used | |
142 | * without their linker symbol being referenced explicitly. For example, | |
143 | * interrupt vector handlers, or functions in the kernel image that are found | |
144 | * programatically. | |
145 | * | |
146 | * Not required for symbols exported with EXPORT_SYMBOL, or initcalls. Those | |
147 | * are handled in their own way (with KEEP() in linker scripts). | |
148 | * | |
149 | * KENTRY can be avoided if the symbols in question are marked as KEEP() in the | |
150 | * linker script. For example an architecture could KEEP() its entire | |
151 | * boot/exception vector code rather than annotate each function and data. | |
152 | */ | |
153 | #ifndef KENTRY | |
154 | # define KENTRY(sym) \ | |
155 | extern typeof(sym) sym; \ | |
156 | static const unsigned long __kentry_##sym \ | |
157 | __used \ | |
e04462fb | 158 | __section("___kentry" "+" #sym ) \ |
b67067f1 NP |
159 | = (unsigned long)&sym; |
160 | #endif | |
161 | ||
1da177e4 LT |
162 | #ifndef RELOC_HIDE |
163 | # define RELOC_HIDE(ptr, off) \ | |
164 | ({ unsigned long __ptr; \ | |
165 | __ptr = (unsigned long) (ptr); \ | |
166 | (typeof(ptr)) (__ptr + (off)); }) | |
167 | #endif | |
168 | ||
fe8c8a12 | 169 | #ifndef OPTIMIZER_HIDE_VAR |
3e2ffd65 MT |
170 | /* Make the optimizer believe the variable can be manipulated arbitrarily. */ |
171 | #define OPTIMIZER_HIDE_VAR(var) \ | |
172 | __asm__ ("" : "=r" (var) : "0" (var)) | |
fe8c8a12 CEB |
173 | #endif |
174 | ||
6f33d587 RR |
175 | /* Not-quite-unique ID. */ |
176 | #ifndef __UNIQUE_ID | |
177 | # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__) | |
178 | #endif | |
179 | ||
230fa253 CB |
180 | #include <uapi/linux/types.h> |
181 | ||
d976441f AR |
182 | #define __READ_ONCE_SIZE \ |
183 | ({ \ | |
184 | switch (size) { \ | |
185 | case 1: *(__u8 *)res = *(volatile __u8 *)p; break; \ | |
186 | case 2: *(__u16 *)res = *(volatile __u16 *)p; break; \ | |
187 | case 4: *(__u32 *)res = *(volatile __u32 *)p; break; \ | |
188 | case 8: *(__u64 *)res = *(volatile __u64 *)p; break; \ | |
189 | default: \ | |
190 | barrier(); \ | |
191 | __builtin_memcpy((void *)res, (const void *)p, size); \ | |
192 | barrier(); \ | |
193 | } \ | |
194 | }) | |
195 | ||
196 | static __always_inline | |
197 | void __read_once_size(const volatile void *p, void *res, int size) | |
230fa253 | 198 | { |
d976441f AR |
199 | __READ_ONCE_SIZE; |
200 | } | |
201 | ||
202 | #ifdef CONFIG_KASAN | |
203 | /* | |
bdb5ac80 | 204 | * We can't declare function 'inline' because __no_sanitize_address confilcts |
d976441f AR |
205 | * with inlining. Attempt to inline it may cause a build failure. |
206 | * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 | |
207 | * '__maybe_unused' allows us to avoid defined-but-not-used warnings. | |
208 | */ | |
163c8d54 | 209 | # define __no_kasan_or_inline __no_sanitize_address notrace __maybe_unused |
d976441f | 210 | #else |
bdb5ac80 AR |
211 | # define __no_kasan_or_inline __always_inline |
212 | #endif | |
213 | ||
214 | static __no_kasan_or_inline | |
d976441f AR |
215 | void __read_once_size_nocheck(const volatile void *p, void *res, int size) |
216 | { | |
217 | __READ_ONCE_SIZE; | |
230fa253 CB |
218 | } |
219 | ||
43239cbe | 220 | static __always_inline void __write_once_size(volatile void *p, void *res, int size) |
230fa253 CB |
221 | { |
222 | switch (size) { | |
223 | case 1: *(volatile __u8 *)p = *(__u8 *)res; break; | |
224 | case 2: *(volatile __u16 *)p = *(__u16 *)res; break; | |
225 | case 4: *(volatile __u32 *)p = *(__u32 *)res; break; | |
230fa253 | 226 | case 8: *(volatile __u64 *)p = *(__u64 *)res; break; |
230fa253 CB |
227 | default: |
228 | barrier(); | |
229 | __builtin_memcpy((void *)p, (const void *)res, size); | |
230fa253 CB |
230 | barrier(); |
231 | } | |
232 | } | |
233 | ||
234 | /* | |
235 | * Prevent the compiler from merging or refetching reads or writes. The | |
236 | * compiler is also forbidden from reordering successive instances of | |
b899a850 MR |
237 | * READ_ONCE and WRITE_ONCE, but only when the compiler is aware of some |
238 | * particular ordering. One way to make the compiler aware of ordering is to | |
239 | * put the two invocations of READ_ONCE or WRITE_ONCE in different C | |
240 | * statements. | |
230fa253 | 241 | * |
b899a850 MR |
242 | * These two macros will also work on aggregate data types like structs or |
243 | * unions. If the size of the accessed data type exceeds the word size of | |
244 | * the machine (e.g., 32 bits or 64 bits) READ_ONCE() and WRITE_ONCE() will | |
245 | * fall back to memcpy(). There's at least two memcpy()s: one for the | |
246 | * __builtin_memcpy() and then one for the macro doing the copy of variable | |
247 | * - '__u' allocated on the stack. | |
230fa253 CB |
248 | * |
249 | * Their two major use cases are: (1) Mediating communication between | |
250 | * process-level code and irq/NMI handlers, all running on the same CPU, | |
b899a850 | 251 | * and (2) Ensuring that the compiler does not fold, spindle, or otherwise |
230fa253 CB |
252 | * mutilate accesses that either do not require ordering or that interact |
253 | * with an explicit memory barrier or atomic instruction that provides the | |
254 | * required ordering. | |
255 | */ | |
d1515582 | 256 | #include <asm/barrier.h> |
7f1e541f | 257 | #include <linux/kasan-checks.h> |
230fa253 | 258 | |
d976441f AR |
259 | #define __READ_ONCE(x, check) \ |
260 | ({ \ | |
261 | union { typeof(x) __val; char __c[1]; } __u; \ | |
262 | if (check) \ | |
263 | __read_once_size(&(x), __u.__c, sizeof(x)); \ | |
264 | else \ | |
265 | __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ | |
76ebbe78 | 266 | smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ |
d976441f AR |
267 | __u.__val; \ |
268 | }) | |
269 | #define READ_ONCE(x) __READ_ONCE(x, 1) | |
270 | ||
271 | /* | |
272 | * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need | |
273 | * to hide memory access from KASAN. | |
274 | */ | |
275 | #define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0) | |
230fa253 | 276 | |
7f1e541f AR |
277 | static __no_kasan_or_inline |
278 | unsigned long read_word_at_a_time(const void *addr) | |
279 | { | |
280 | kasan_check_read(addr, 1); | |
281 | return *(unsigned long *)addr; | |
282 | } | |
283 | ||
43239cbe | 284 | #define WRITE_ONCE(x, val) \ |
ba33034f CB |
285 | ({ \ |
286 | union { typeof(x) __val; char __c[1]; } __u = \ | |
287 | { .__val = (__force typeof(x)) (val) }; \ | |
288 | __write_once_size(&(x), __u.__c, sizeof(x)); \ | |
289 | __u.__val; \ | |
290 | }) | |
230fa253 | 291 | |
1da177e4 LT |
292 | #endif /* __KERNEL__ */ |
293 | ||
7290d580 AB |
294 | /* |
295 | * Force the compiler to emit 'sym' as a symbol, so that we can reference | |
296 | * it from inline assembler. Necessary in case 'sym' could be inlined | |
297 | * otherwise, or eliminated entirely due to lack of references that are | |
298 | * visible to the compiler. | |
299 | */ | |
300 | #define __ADDRESSABLE(sym) \ | |
bfafddd8 | 301 | static void * __section(.discard.addressable) __used \ |
7290d580 AB |
302 | __PASTE(__addressable_##sym, __LINE__) = (void *)&sym; |
303 | ||
304 | /** | |
305 | * offset_to_ptr - convert a relative memory offset to an absolute pointer | |
306 | * @off: the address of the 32-bit offset value | |
307 | */ | |
308 | static inline void *offset_to_ptr(const int *off) | |
309 | { | |
310 | return (void *)((unsigned long)off + *off); | |
311 | } | |
312 | ||
1da177e4 LT |
313 | #endif /* __ASSEMBLY__ */ |
314 | ||
9f0cf4ad AV |
315 | /* Compile time object size, -1 for unknown */ |
316 | #ifndef __compiletime_object_size | |
317 | # define __compiletime_object_size(obj) -1 | |
318 | #endif | |
4a312769 AV |
319 | #ifndef __compiletime_warning |
320 | # define __compiletime_warning(message) | |
321 | #endif | |
63312b6a AV |
322 | #ifndef __compiletime_error |
323 | # define __compiletime_error(message) | |
324 | #endif | |
c361d3e5 | 325 | |
c03567a8 JS |
326 | #ifdef __OPTIMIZE__ |
327 | # define __compiletime_assert(condition, msg, prefix, suffix) \ | |
9a8ab1c3 | 328 | do { \ |
9a8ab1c3 | 329 | extern void prefix ## suffix(void) __compiletime_error(msg); \ |
81b45683 | 330 | if (!(condition)) \ |
9a8ab1c3 | 331 | prefix ## suffix(); \ |
9a8ab1c3 | 332 | } while (0) |
c03567a8 JS |
333 | #else |
334 | # define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0) | |
335 | #endif | |
9a8ab1c3 DS |
336 | |
337 | #define _compiletime_assert(condition, msg, prefix, suffix) \ | |
338 | __compiletime_assert(condition, msg, prefix, suffix) | |
339 | ||
340 | /** | |
341 | * compiletime_assert - break build and emit msg if condition is false | |
342 | * @condition: a compile-time constant condition to check | |
343 | * @msg: a message to emit if condition is false | |
344 | * | |
345 | * In tradition of POSIX assert, this macro will break the build if the | |
346 | * supplied condition is *false*, emitting the supplied error message if the | |
347 | * compiler has support to do so. | |
348 | */ | |
349 | #define compiletime_assert(condition, msg) \ | |
af9c5d2e | 350 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) |
9a8ab1c3 | 351 | |
47933ad4 PZ |
352 | #define compiletime_assert_atomic_type(t) \ |
353 | compiletime_assert(__native_word(t), \ | |
354 | "Need native word sized stores/loads for atomicity.") | |
355 | ||
ec0bbef6 MO |
356 | /* &a[0] degrades to a pointer: a different type from an array */ |
357 | #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) | |
ec0bbef6 | 358 | |
1da177e4 | 359 | #endif /* __LINUX_COMPILER_H */ |