1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __LINUX_COMPILER_TYPES_H
3#define __LINUX_COMPILER_TYPES_H
4
5/*
6 * __has_builtin is supported on gcc >= 10, clang >= 3 and icc >= 21.
7 * In the meantime, to support gcc < 10, we implement __has_builtin
8 * by hand.
9 */
10#ifndef __has_builtin
11#define __has_builtin(x) (0)
12#endif
13
14#ifndef __ASSEMBLY__
15
16/*
17 * Skipped when running bindgen due to a libclang issue;
18 * see https://github.com/rust-lang/rust-bindgen/issues/2244.
19 */
20#if defined(CONFIG_DEBUG_INFO_BTF) && defined(CONFIG_PAHOLE_HAS_BTF_TAG) && \
21 __has_attribute(btf_type_tag) && !defined(__BINDGEN__)
22# define BTF_TYPE_TAG(value) __attribute__((btf_type_tag(#value)))
23#else
24# define BTF_TYPE_TAG(value) /* nothing */
25#endif
26
27/* sparse defines __CHECKER__; see Documentation/dev-tools/sparse.rst */
28#ifdef __CHECKER__
29/* address spaces */
30# define __kernel __attribute__((address_space(0)))
31# define __user __attribute__((noderef, address_space(__user)))
32# define __iomem __attribute__((noderef, address_space(__iomem)))
33# define __percpu __attribute__((noderef, address_space(__percpu)))
34# define __rcu __attribute__((noderef, address_space(__rcu)))
35static inline void __chk_user_ptr(const volatile void __user *ptr) { }
36static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
37/* context/locking */
38# define __must_hold(x) __attribute__((context(x,1,1)))
39# define __acquires(x) __attribute__((context(x,0,1)))
40# define __cond_acquires(x) __attribute__((context(x,0,-1)))
41# define __releases(x) __attribute__((context(x,1,0)))
42# define __acquire(x) __context__(x,1)
43# define __release(x) __context__(x,-1)
44# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
45/* other */
46# define __force __attribute__((force))
47# define __nocast __attribute__((nocast))
48# define __safe __attribute__((safe))
49# define __private __attribute__((noderef))
50# define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(p)->member))
51#else /* __CHECKER__ */
52/* address spaces */
53# define __kernel
54# ifdef STRUCTLEAK_PLUGIN
55# define __user __attribute__((user))
56# else
57# define __user BTF_TYPE_TAG(user)
58# endif
59# define __iomem
60# define __percpu BTF_TYPE_TAG(percpu)
61# define __rcu BTF_TYPE_TAG(rcu)
62
63# define __chk_user_ptr(x) (void)0
64# define __chk_io_ptr(x) (void)0
65/* context/locking */
66# define __must_hold(x)
67# define __acquires(x)
68# define __cond_acquires(x)
69# define __releases(x)
70# define __acquire(x) (void)0
71# define __release(x) (void)0
72# define __cond_lock(x,c) (c)
73/* other */
74# define __force
75# define __nocast
76# define __safe
77# define __private
78# define ACCESS_PRIVATE(p, member) ((p)->member)
79# define __builtin_warning(x, y...) (1)
80#endif /* __CHECKER__ */
81
82/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
83#define ___PASTE(a,b) a##b
84#define __PASTE(a,b) ___PASTE(a,b)
85
86#ifdef __KERNEL__
87
88/* Attributes */
89#include <linux/compiler_attributes.h>
90
91#if CONFIG_FUNCTION_ALIGNMENT > 0
92#define __function_aligned __aligned(CONFIG_FUNCTION_ALIGNMENT)
93#else
94#define __function_aligned
95#endif
96
97/*
98 * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute
99 * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute
100 *
101 * When -falign-functions=N is in use, we must avoid the cold attribute as
102 * GCC drops the alignment for cold functions. Worse, GCC can implicitly mark
103 * callees of cold functions as cold themselves, so it's not sufficient to add
104 * __function_aligned here as that will not ensure that callees are correctly
105 * aligned.
106 *
107 * See:
108 *
109 * https://lore.kernel.org/lkml/Y77%2FqVgvaJidFpYt@FVFF77S0Q05N
110 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c9
111 */
112#if defined(CONFIG_CC_HAS_SANE_FUNCTION_ALIGNMENT) || (CONFIG_FUNCTION_ALIGNMENT == 0)
113#define __cold __attribute__((__cold__))
114#else
115#define __cold
116#endif
117
118/*
119 * On x86-64 and arm64 targets, __preserve_most changes the calling convention
120 * of a function to make the code in the caller as unintrusive as possible. This
121 * convention behaves identically to the C calling convention on how arguments
122 * and return values are passed, but uses a different set of caller- and callee-
123 * saved registers.
124 *
125 * The purpose is to alleviates the burden of saving and recovering a large
126 * register set before and after the call in the caller. This is beneficial for
127 * rarely taken slow paths, such as error-reporting functions that may be called
128 * from hot paths.
129 *
130 * Note: This may conflict with instrumentation inserted on function entry which
131 * does not use __preserve_most or equivalent convention (if in assembly). Since
132 * function tracing assumes the normal C calling convention, where the attribute
133 * is supported, __preserve_most implies notrace. It is recommended to restrict
134 * use of the attribute to functions that should or already disable tracing.
135 *
136 * Optional: not supported by gcc.
137 *
138 * clang: https://clang.llvm.org/docs/AttributeReference.html#preserve-most
139 */
140#if __has_attribute(__preserve_most__) && (defined(CONFIG_X86_64) || defined(CONFIG_ARM64))
141# define __preserve_most notrace __attribute__((__preserve_most__))
142#else
143# define __preserve_most
144#endif
145
146/* Compiler specific macros. */
147#ifdef __clang__
148#include <linux/compiler-clang.h>
149#elif defined(__GNUC__)
150/* The above compilers also define __GNUC__, so order is important here. */
151#include <linux/compiler-gcc.h>
152#else
153#error "Unknown compiler"
154#endif
155
156/*
157 * Some architectures need to provide custom definitions of macros provided
158 * by linux/compiler-*.h, and can do so using asm/compiler.h. We include that
159 * conditionally rather than using an asm-generic wrapper in order to avoid
160 * build failures if any C compilation, which will include this file via an
161 * -include argument in c_flags, occurs prior to the asm-generic wrappers being
162 * generated.
163 */
164#ifdef CONFIG_HAVE_ARCH_COMPILER_H
165#include <asm/compiler.h>
166#endif
167
168struct ftrace_branch_data {
169 const char *func;
170 const char *file;
171 unsigned line;
172 union {
173 struct {
174 unsigned long correct;
175 unsigned long incorrect;
176 };
177 struct {
178 unsigned long miss;
179 unsigned long hit;
180 };
181 unsigned long miss_hit[2];
182 };
183};
184
185struct ftrace_likely_data {
186 struct ftrace_branch_data data;
187 unsigned long constant;
188};
189
190#if defined(CC_USING_HOTPATCH)
191#define notrace __attribute__((hotpatch(0, 0)))
192#elif defined(CC_USING_PATCHABLE_FUNCTION_ENTRY)
193#define notrace __attribute__((patchable_function_entry(0, 0)))
194#else
195#define notrace __attribute__((__no_instrument_function__))
196#endif
197
198/*
199 * it doesn't make sense on ARM (currently the only user of __naked)
200 * to trace naked functions because then mcount is called without
201 * stack and frame pointer being set up and there is no chance to
202 * restore the lr register to the value before mcount was called.
203 */
204#define __naked __attribute__((__naked__)) notrace
205
206/*
207 * Prefer gnu_inline, so that extern inline functions do not emit an
208 * externally visible function. This makes extern inline behave as per gnu89
209 * semantics rather than c99. This prevents multiple symbol definition errors
210 * of extern inline functions at link time.
211 * A lot of inline functions can cause havoc with function tracing.
212 */
213#define inline inline __gnu_inline __inline_maybe_unused notrace
214
215/*
216 * gcc provides both __inline__ and __inline as alternate spellings of
217 * the inline keyword, though the latter is undocumented. New kernel
218 * code should only use the inline spelling, but some existing code
219 * uses __inline__. Since we #define inline above, to ensure
220 * __inline__ has the same semantics, we need this #define.
221 *
222 * However, the spelling __inline is strictly reserved for referring
223 * to the bare keyword.
224 */
225#define __inline__ inline
226
227/*
228 * GCC does not warn about unused static inline functions for -Wunused-function.
229 * Suppress the warning in clang as well by using __maybe_unused, but enable it
230 * for W=1 build. This will allow clang to find unused functions. Remove the
231 * __inline_maybe_unused entirely after fixing most of -Wunused-function warnings.
232 */
233#ifdef KBUILD_EXTRA_WARN1
234#define __inline_maybe_unused
235#else
236#define __inline_maybe_unused __maybe_unused
237#endif
238
239/*
240 * Rather then using noinline to prevent stack consumption, use
241 * noinline_for_stack instead. For documentation reasons.
242 */
243#define noinline_for_stack noinline
244
245/*
246 * Sanitizer helper attributes: Because using __always_inline and
247 * __no_sanitize_* conflict, provide helper attributes that will either expand
248 * to __no_sanitize_* in compilation units where instrumentation is enabled
249 * (__SANITIZE_*__), or __always_inline in compilation units without
250 * instrumentation (__SANITIZE_*__ undefined).
251 */
252#ifdef __SANITIZE_ADDRESS__
253/*
254 * We can't declare function 'inline' because __no_sanitize_address conflicts
255 * with inlining. Attempt to inline it may cause a build failure.
256 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
257 * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
258 */
259# define __no_kasan_or_inline __no_sanitize_address notrace __maybe_unused
260# define __no_sanitize_or_inline __no_kasan_or_inline
261#else
262# define __no_kasan_or_inline __always_inline
263#endif
264
265#ifdef __SANITIZE_THREAD__
266/*
267 * Clang still emits instrumentation for __tsan_func_{entry,exit}() and builtin
268 * atomics even with __no_sanitize_thread (to avoid false positives in userspace
269 * ThreadSanitizer). The kernel's requirements are stricter and we really do not
270 * want any instrumentation with __no_kcsan.
271 *
272 * Therefore we add __disable_sanitizer_instrumentation where available to
273 * disable all instrumentation. See Kconfig.kcsan where this is mandatory.
274 */
275# define __no_kcsan __no_sanitize_thread __disable_sanitizer_instrumentation
276# define __no_sanitize_or_inline __no_kcsan notrace __maybe_unused
277#else
278# define __no_kcsan
279#endif
280
281#ifndef __no_sanitize_or_inline
282#define __no_sanitize_or_inline __always_inline
283#endif
284
285/* Do not trap wrapping arithmetic within an annotated function. */
286#ifdef CONFIG_UBSAN_SIGNED_WRAP
287# define __signed_wrap __attribute__((no_sanitize("signed-integer-overflow")))
288#else
289# define __signed_wrap
290#endif
291
292/* Section for code which can't be instrumented at all */
293#define __noinstr_section(section) \
294 noinline notrace __attribute((__section__(section))) \
295 __no_kcsan __no_sanitize_address __no_profile __no_sanitize_coverage \
296 __no_sanitize_memory __signed_wrap
297
298#define noinstr __noinstr_section(".noinstr.text")
299
300/*
301 * The __cpuidle section is used twofold:
302 *
303 * 1) the original use -- identifying if a CPU is 'stuck' in idle state based
304 * on it's instruction pointer. See cpu_in_idle().
305 *
306 * 2) supressing instrumentation around where cpuidle disables RCU; where the
307 * function isn't strictly required for #1, this is interchangeable with
308 * noinstr.
309 */
310#define __cpuidle __noinstr_section(".cpuidle.text")
311
312#endif /* __KERNEL__ */
313
314#endif /* __ASSEMBLY__ */
315
316/*
317 * The below symbols may be defined for one or more, but not ALL, of the above
318 * compilers. We don't consider that to be an error, so set them to nothing.
319 * For example, some of them are for compiler specific plugins.
320 */
321#ifndef __latent_entropy
322# define __latent_entropy
323#endif
324
325#if defined(RANDSTRUCT) && !defined(__CHECKER__)
326# define __randomize_layout __designated_init __attribute__((randomize_layout))
327# define __no_randomize_layout __attribute__((no_randomize_layout))
328/* This anon struct can add padding, so only enable it under randstruct. */
329# define randomized_struct_fields_start struct {
330# define randomized_struct_fields_end } __randomize_layout;
331#else
332# define __randomize_layout __designated_init
333# define __no_randomize_layout
334# define randomized_struct_fields_start
335# define randomized_struct_fields_end
336#endif
337
338#ifndef __noscs
339# define __noscs
340#endif
341
342#ifndef __nocfi
343# define __nocfi
344#endif
345
346/*
347 * Any place that could be marked with the "alloc_size" attribute is also
348 * a place to be marked with the "malloc" attribute, except those that may
349 * be performing a _reallocation_, as that may alias the existing pointer.
350 * For these, use __realloc_size().
351 */
352#ifdef __alloc_size__
353# define __alloc_size(x, ...) __alloc_size__(x, ## __VA_ARGS__) __malloc
354# define __realloc_size(x, ...) __alloc_size__(x, ## __VA_ARGS__)
355#else
356# define __alloc_size(x, ...) __malloc
357# define __realloc_size(x, ...)
358#endif
359
360/*
361 * When the size of an allocated object is needed, use the best available
362 * mechanism to find it. (For cases where sizeof() cannot be used.)
363 */
364#if __has_builtin(__builtin_dynamic_object_size)
365#define __struct_size(p) __builtin_dynamic_object_size(p, 0)
366#define __member_size(p) __builtin_dynamic_object_size(p, 1)
367#else
368#define __struct_size(p) __builtin_object_size(p, 0)
369#define __member_size(p) __builtin_object_size(p, 1)
370#endif
371
372/*
373 * Some versions of gcc do not mark 'asm goto' volatile:
374 *
375 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103979
376 *
377 * We do it here by hand, because it doesn't hurt.
378 */
379#ifndef asm_goto_output
380#define asm_goto_output(x...) asm volatile goto(x)
381#endif
382
383#ifdef CONFIG_CC_HAS_ASM_INLINE
384#define asm_inline asm __inline
385#else
386#define asm_inline asm
387#endif
388
389/* Are two types/vars the same type (ignoring qualifiers)? */
390#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
391
392/*
393 * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
394 * non-scalar types unchanged.
395 */
396/*
397 * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
398 * is not type-compatible with 'signed char', and we define a separate case.
399 */
400#define __scalar_type_to_expr_cases(type) \
401 unsigned type: (unsigned type)0, \
402 signed type: (signed type)0
403
404#define __unqual_scalar_typeof(x) typeof( \
405 _Generic((x), \
406 char: (char)0, \
407 __scalar_type_to_expr_cases(char), \
408 __scalar_type_to_expr_cases(short), \
409 __scalar_type_to_expr_cases(int), \
410 __scalar_type_to_expr_cases(long), \
411 __scalar_type_to_expr_cases(long long), \
412 default: (x)))
413
414/* Is this type a native word size -- useful for atomic operations */
415#define __native_word(t) \
416 (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \
417 sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
418
419#ifdef __OPTIMIZE__
420# define __compiletime_assert(condition, msg, prefix, suffix) \
421 do { \
422 /* \
423 * __noreturn is needed to give the compiler enough \
424 * information to avoid certain possibly-uninitialized \
425 * warnings (regardless of the build failing). \
426 */ \
427 __noreturn extern void prefix ## suffix(void) \
428 __compiletime_error(msg); \
429 if (!(condition)) \
430 prefix ## suffix(); \
431 } while (0)
432#else
433# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)
434#endif
435
436#define _compiletime_assert(condition, msg, prefix, suffix) \
437 __compiletime_assert(condition, msg, prefix, suffix)
438
439/**
440 * compiletime_assert - break build and emit msg if condition is false
441 * @condition: a compile-time constant condition to check
442 * @msg: a message to emit if condition is false
443 *
444 * In tradition of POSIX assert, this macro will break the build if the
445 * supplied condition is *false*, emitting the supplied error message if the
446 * compiler has support to do so.
447 */
448#define compiletime_assert(condition, msg) \
449 _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
450
451#define compiletime_assert_atomic_type(t) \
452 compiletime_assert(__native_word(t), \
453 "Need native word sized stores/loads for atomicity.")
454
455/* Helpers for emitting diagnostics in pragmas. */
456#ifndef __diag
457#define __diag(string)
458#endif
459
460#ifndef __diag_GCC
461#define __diag_GCC(version, severity, string)
462#endif
463
464#define __diag_push() __diag(push)
465#define __diag_pop() __diag(pop)
466
467#define __diag_ignore(compiler, version, option, comment) \
468 __diag_ ## compiler(version, ignore, option)
469#define __diag_warn(compiler, version, option, comment) \
470 __diag_ ## compiler(version, warn, option)
471#define __diag_error(compiler, version, option, comment) \
472 __diag_ ## compiler(version, error, option)
473
474#ifndef __diag_ignore_all
475#define __diag_ignore_all(option, comment)
476#endif
477
478#endif /* __LINUX_COMPILER_TYPES_H */
479

source code of linux/include/linux/compiler_types.h