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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001/* SPDX-License-Identifier: GPL-2.0 */
Will Deacond1515582017-10-24 11:22:46 +01002#ifndef __LINUX_COMPILER_TYPES_H
Robert P. J. Day94f582f2007-10-16 23:26:11 -07003#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
4#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07005
6/*
7 * Common definitions for all gcc versions go here.
8 */
Joe Perchesf6d133f82015-06-25 15:01:00 -07009#define GCC_VERSION (__GNUC__ * 10000 \
10 + __GNUC_MINOR__ * 100 \
11 + __GNUC_PATCHLEVEL__)
Linus Torvalds1da177e2005-04-16 15:20:36 -070012
Joe Perchescafa0012018-08-20 13:15:26 -070013#if GCC_VERSION < 40600
14# error Sorry, your compiler is too old - please upgrade it.
15#endif
16
Linus Torvalds1da177e2005-04-16 15:20:36 -070017/* Optimization barrier */
Daniel Borkmann7829fb02015-04-30 04:13:52 +020018
Linus Torvalds1da177e2005-04-16 15:20:36 -070019/* The "volatile" is due to gcc bugs */
20#define barrier() __asm__ __volatile__("": : :"memory")
Daniel Borkmann7829fb02015-04-30 04:13:52 +020021/*
22 * This version is i.e. to prevent dead stores elimination on @ptr
23 * where gcc and llvm may behave differently when otherwise using
24 * normal barrier(): while gcc behavior gets along with a normal
25 * barrier(), llvm needs an explicit input variable to be assumed
26 * clobbered. The issue is as follows: while the inline asm might
27 * access any memory it wants, the compiler could have fit all of
28 * @ptr into memory registers instead, and since @ptr never escaped
Benjamin Peterson8e8780a2016-12-12 16:45:38 -080029 * from that, it proved that the inline asm wasn't touching any of
Daniel Borkmann7829fb02015-04-30 04:13:52 +020030 * it. This version works well with both compilers, i.e. we're telling
31 * the compiler that the inline asm absolutely may see the contents
32 * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
33 */
34#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
Anton Blanchardc8d52462006-01-10 18:21:20 +110036/*
Andi Kleen85c210e2009-01-09 16:40:53 -080037 * This macro obfuscates arithmetic on a variable address so that gcc
38 * shouldn't recognize the original var, and make assumptions about it.
39 *
40 * This is needed because the C standard makes it undefined to do
41 * pointer arithmetic on "objects" outside their boundaries and the
42 * gcc optimizers assume this is the case. In particular they
43 * assume such arithmetic does not wrap.
44 *
45 * A miscompilation has been observed because of this on PPC.
46 * To work around it we hide the relationship of the pointer and the object
47 * using this macro.
48 *
Anton Blanchardc8d52462006-01-10 18:21:20 +110049 * Versions of the ppc64 compiler before 4.1 had a bug where use of
50 * RELOC_HIDE could trash r30. The bug can be worked around by changing
51 * the inline assembly constraint from =g to =r, in this particular
52 * case either is valid.
53 */
Joe Perchesf6d133f82015-06-25 15:01:00 -070054#define RELOC_HIDE(ptr, off) \
55({ \
56 unsigned long __ptr; \
57 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
58 (typeof(ptr)) (__ptr + (off)); \
59})
Andrew Mortona1365642006-01-08 01:04:09 -080060
Cesar Eduardo Barrosfe8c8a12013-11-25 22:00:41 -020061/* Make the optimizer believe the variable can be manipulated arbitrarily. */
Joe Perchesf6d133f82015-06-25 15:01:00 -070062#define OPTIMIZER_HIDE_VAR(var) \
63 __asm__ ("" : "=r" (var) : "0" (var))
Cesar Eduardo Barrosfe8c8a12013-11-25 22:00:41 -020064
Joe Perchescafa0012018-08-20 13:15:26 -070065/*
66 * A trick to suppress uninitialized variable warning without generating any
67 * code
68 */
69#define uninitialized_var(x) x = x
70
KOSAKI Motohiro5bd7e6a2011-05-24 17:13:17 -070071#ifdef __CHECKER__
Joe Perchesf6d133f82015-06-25 15:01:00 -070072#define __must_be_array(a) 0
KOSAKI Motohiro5bd7e6a2011-05-24 17:13:17 -070073#else
Rusty Russellc5e631cf2007-05-06 14:51:05 -070074/* &a[0] degrades to a pointer: a different type from an array */
Joe Perchesf6d133f82015-06-25 15:01:00 -070075#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
KOSAKI Motohiro5bd7e6a2011-05-24 17:13:17 -070076#endif
Andrew Mortona1365642006-01-08 01:04:09 -080077
Ingo Molnar60a3cdd2008-03-03 12:38:52 +010078/*
Nick Desaulniersd03db2b2018-06-21 09:23:22 -070079 * Feature detection for gnu_inline (gnu89 extern inline semantics). Either
80 * __GNUC_STDC_INLINE__ is defined (not using gnu89 extern inline semantics,
81 * and we opt in to the gnu89 semantics), or __GNUC_STDC_INLINE__ is not
82 * defined so the gnu89 semantics are the default.
83 */
84#ifdef __GNUC_STDC_INLINE__
85# define __gnu_inline __attribute__((gnu_inline))
86#else
87# define __gnu_inline
88#endif
89
90/*
Ingo Molnarae3a0062008-04-30 00:15:31 +020091 * Force always-inline if the user requests it so via the .config,
David Rientjes9a04dbc2017-07-06 15:35:24 -070092 * or if gcc is too old.
93 * GCC does not warn about unused static inline functions for
94 * -Wunused-function. This turns out to avoid the need for complex #ifdef
95 * directives. Suppress the warning in clang as well by using "unused"
96 * function attribute, which is redundant but not harmful for gcc.
Nick Desaulniersd03db2b2018-06-21 09:23:22 -070097 * Prefer gnu_inline, so that extern inline functions do not emit an
98 * externally visible function. This makes extern inline behave as per gnu89
99 * semantics rather than c99. This prevents multiple symbol definition errors
100 * of extern inline functions at link time.
101 * A lot of inline functions can cause havoc with function tracing.
Ingo Molnar60a3cdd2008-03-03 12:38:52 +0100102 */
Joe Perchesf6d133f82015-06-25 15:01:00 -0700103#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
Joe Perchescafa0012018-08-20 13:15:26 -0700104 !defined(CONFIG_OPTIMIZE_INLINING)
Nick Desaulniersd03db2b2018-06-21 09:23:22 -0700105#define inline \
106 inline __attribute__((always_inline, unused)) notrace __gnu_inline
Steven Rostedt45959ee2011-12-12 15:22:41 -0500107#else
Nick Desaulniersd03db2b2018-06-21 09:23:22 -0700108#define inline inline __attribute__((unused)) notrace __gnu_inline
Ingo Molnar60a3cdd2008-03-03 12:38:52 +0100109#endif
110
Nick Desaulniersd03db2b2018-06-21 09:23:22 -0700111#define __inline__ inline
112#define __inline inline
Joe Perchesf6d133f82015-06-25 15:01:00 -0700113#define __always_inline inline __attribute__((always_inline))
114#define noinline __attribute__((noinline))
115
Joe Perchesf6d133f82015-06-25 15:01:00 -0700116#define __packed __attribute__((packed))
117#define __weak __attribute__((weak))
118#define __alias(symbol) __attribute__((alias(#symbol)))
Uwe Kleine-König446c92b2009-03-12 18:03:16 +0100119
David Woodhouse87358712018-02-19 10:50:57 +0000120#ifdef RETPOLINE
121#define __noretpoline __attribute__((indirect_branch("keep")))
122#endif
123
Uwe Kleine-König446c92b2009-03-12 18:03:16 +0100124/*
Joe Perchesf6d133f82015-06-25 15:01:00 -0700125 * it doesn't make sense on ARM (currently the only user of __naked)
126 * to trace naked functions because then mcount is called without
127 * stack and frame pointer being set up and there is no chance to
128 * restore the lr register to the value before mcount was called.
Mikael Pettersson9c695202010-06-29 15:05:25 -0700129 *
Joe Perchesf6d133f82015-06-25 15:01:00 -0700130 * The asm() bodies of naked functions often depend on standard calling
131 * conventions, therefore they must be noinline and noclone.
132 *
133 * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
134 * See GCC PR44290.
Uwe Kleine-König446c92b2009-03-12 18:03:16 +0100135 */
Joe Perchesf6d133f82015-06-25 15:01:00 -0700136#define __naked __attribute__((naked)) noinline __noclone notrace
Uwe Kleine-König446c92b2009-03-12 18:03:16 +0100137
Joe Perchesf6d133f82015-06-25 15:01:00 -0700138#define __noreturn __attribute__((noreturn))
Ralf Baechlee8c44312007-10-18 03:07:07 -0700139
140/*
141 * From the GCC manual:
142 *
143 * Many functions have no effects except the return value and their
144 * return value depends only on the parameters and/or global
145 * variables. Such a function can be subject to common subexpression
146 * elimination and loop optimization just as an arithmetic operator
147 * would be.
148 * [...]
149 */
Joe Perchesf6d133f82015-06-25 15:01:00 -0700150#define __pure __attribute__((pure))
151#define __aligned(x) __attribute__((aligned(x)))
Gideon Israel Dsouzad8c34b92016-12-31 21:26:23 +0530152#define __aligned_largest __attribute__((aligned))
Joe Perchesf6d133f82015-06-25 15:01:00 -0700153#define __printf(a, b) __attribute__((format(printf, a, b)))
154#define __scanf(a, b) __attribute__((format(scanf, a, b)))
155#define __attribute_const__ __attribute__((__const__))
156#define __maybe_unused __attribute__((unused))
157#define __always_unused __attribute__((unused))
Gideon Israel Dsouzaa3f08252017-02-24 15:00:32 -0800158#define __mode(x) __attribute__((mode(x)))
Linus Torvaldsf153b822009-01-02 09:23:03 -0800159
Joe Perchescb984d12015-06-25 15:01:02 -0700160#define __must_check __attribute__((warn_unused_result))
Rasmus Villemoesd64e85d2016-05-19 17:10:52 -0700161#define __malloc __attribute__((__malloc__))
Joe Perchescb984d12015-06-25 15:01:02 -0700162
163#define __used __attribute__((__used__))
164#define __compiler_offsetof(a, b) \
165 __builtin_offsetof(a, b)
166
Joe Perchescb984d12015-06-25 15:01:02 -0700167/* Mark functions as cold. gcc will assume any path leading to a call
168 * to them will be unlikely. This means a lot of manual unlikely()s
169 * are unnecessary now for any paths leading to the usual suspects
170 * like BUG(), printk(), panic() etc. [but let's keep them for now for
171 * older compilers]
172 *
173 * Early snapshots of gcc 4.3 don't support this and we can't detect this
174 * in the preprocessor, but we can live with this because they're unreleased.
175 * Maketime probing would be overkill here.
176 *
177 * gcc also has a __attribute__((__hot__)) to move hot functions into
178 * a special section, but I don't see any sense in this right now in
179 * the kernel context
180 */
181#define __cold __attribute__((__cold__))
182
183#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
184
Geert Uytterhoevendf5d45a2018-02-01 11:21:58 +0100185#define __optimize(level) __attribute__((__optimize__(level)))
Geert Uytterhoevend9afaaa2018-02-01 11:21:59 +0100186#define __nostackprotector __optimize("no-stack-protector")
Geert Uytterhoevendf5d45a2018-02-01 11:21:58 +0100187
Joe Perchescafa0012018-08-20 13:15:26 -0700188#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
Emese Revfy0766f782016-06-20 20:42:34 +0200189
190#ifndef __CHECKER__
Joe Perchescafa0012018-08-20 13:15:26 -0700191#define __compiletime_warning(message) __attribute__((warning(message)))
192#define __compiletime_error(message) __attribute__((error(message)))
193
Emese Revfy0766f782016-06-20 20:42:34 +0200194#ifdef LATENT_ENTROPY_PLUGIN
195#define __latent_entropy __attribute__((latent_entropy))
196#endif
Joe Perchescafa0012018-08-20 13:15:26 -0700197#endif /* __CHECKER__ */
Emese Revfy0766f782016-06-20 20:42:34 +0200198
Joe Perchescb984d12015-06-25 15:01:02 -0700199/*
Arnd Bergmann173a3ef2018-02-21 14:45:54 -0800200 * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
201 * confuse the stack allocation in gcc, leading to overly large stack
202 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
203 *
204 * Adding an empty inline assembly before it works around the problem
205 */
206#define barrier_before_unreachable() asm volatile("")
207
208/*
Joe Perchescb984d12015-06-25 15:01:02 -0700209 * Mark a position in code as unreachable. This can be used to
210 * suppress control flow warnings after asm blocks that transfer
211 * control elsewhere.
212 *
213 * Early snapshots of gcc 4.5 don't support this and we can't detect
214 * this in the preprocessor, but we can live with this because they're
215 * unreleased. Really, we need to have autoconf for the kernel.
216 */
Josh Poimboeuf4e4636c2017-02-27 22:21:16 -0600217#define unreachable() \
Arnd Bergmann173a3ef2018-02-21 14:45:54 -0800218 do { \
219 annotate_unreachable(); \
220 barrier_before_unreachable(); \
221 __builtin_unreachable(); \
222 } while (0)
Joe Perchescb984d12015-06-25 15:01:02 -0700223
224/* Mark a function definition as prohibited from being cloned. */
Paolo Bonzini95272c22016-03-31 09:38:51 +0200225#define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
Joe Perchescb984d12015-06-25 15:01:02 -0700226
Matthew Wilcoxa3d6c972018-01-18 16:34:08 -0800227#if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
Kees Cook313dd1b62017-05-05 23:37:45 -0700228#define __randomize_layout __attribute__((randomize_layout))
229#define __no_randomize_layout __attribute__((no_randomize_layout))
Kees Cook2cfe0d32018-04-10 16:32:44 -0700230/* This anon struct can add padding, so only enable it under randstruct. */
231#define randomized_struct_fields_start struct {
232#define randomized_struct_fields_end } __randomize_layout;
Kees Cook313dd1b62017-05-05 23:37:45 -0700233#endif
234
Joe Perchescb984d12015-06-25 15:01:02 -0700235/*
Andrew Morton9add8502015-11-06 16:30:09 -0800236 * When used with Link Time Optimization, gcc can optimize away C functions or
237 * variables which are referenced only from assembly code. __visible tells the
238 * optimizer that something else uses this function or variable, thus preventing
239 * this.
Joe Perchescb984d12015-06-25 15:01:02 -0700240 */
241#define __visible __attribute__((externally_visible))
Kees Cook29e48ce2017-04-05 22:43:33 -0700242
Joe Perchescafa0012018-08-20 13:15:26 -0700243/* gcc version specific checks */
Rasmus Villemoesa744fd12015-11-05 18:45:02 -0800244
Rasmus Villemoes8748dd52015-11-05 18:45:05 -0800245#if GCC_VERSION >= 40900 && !defined(__CHECKER__)
Rasmus Villemoesa744fd12015-11-05 18:45:02 -0800246/*
247 * __assume_aligned(n, k): Tell the optimizer that the returned
248 * pointer can be assumed to be k modulo n. The second argument is
249 * optional (default 0), so we use a variadic macro to make the
250 * shorthand.
251 *
252 * Beware: Do not apply this to functions which may return
253 * ERR_PTRs. Also, it is probably unwise to apply it to functions
254 * returning extra information in the low bits (but in that case the
255 * compiler should see some alignment anyway, when the return value is
256 * massaged by 'flags = ptr & 3; ptr &= ~3;').
257 */
258#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
259#endif
260
Joe Perchescb984d12015-06-25 15:01:02 -0700261/*
262 * GCC 'asm goto' miscompiles certain code sequences:
263 *
264 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
265 *
266 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
267 *
268 * (asm goto is automatically volatile - the naming reflects this.)
269 */
270#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
271
Johannes Berg101b29a2016-08-25 15:16:45 -0700272/*
273 * sparse (__CHECKER__) pretends to be gcc, but can't do constant
274 * folding in __builtin_bswap*() (yet), so don't set these for it.
275 */
276#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
Joe Perchescb984d12015-06-25 15:01:02 -0700277#define __HAVE_BUILTIN_BSWAP32__
278#define __HAVE_BUILTIN_BSWAP64__
Josh Poimboeuf8634de62016-05-06 09:22:25 -0500279#if GCC_VERSION >= 40800
Joe Perchescb984d12015-06-25 15:01:02 -0700280#define __HAVE_BUILTIN_BSWAP16__
281#endif
Johannes Berg101b29a2016-08-25 15:16:45 -0700282#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
Joe Perchescb984d12015-06-25 15:01:02 -0700283
Dmitry Vyukov045d5992016-11-30 15:54:13 -0800284#if GCC_VERSION >= 70000
285#define KASAN_ABI_VERSION 5
286#elif GCC_VERSION >= 50000
Joe Perchescb984d12015-06-25 15:01:02 -0700287#define KASAN_ABI_VERSION 4
288#elif GCC_VERSION >= 40902
289#define KASAN_ABI_VERSION 3
290#endif
291
Andrey Ryabinind9764412015-10-19 11:37:17 +0300292#if GCC_VERSION >= 40902
293/*
294 * Tell the compiler that address safety instrumentation (KASAN)
295 * should not be applied to that function.
296 * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
297 */
298#define __no_sanitize_address __attribute__((no_sanitize_address))
299#endif
300
Kees Cook0aa5e492017-04-05 09:49:19 -0700301#if GCC_VERSION >= 50100
302/*
303 * Mark structures as requiring designated initializers.
304 * https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html
305 */
306#define __designated_init __attribute__((designated_init))
Joe Perchescafa0012018-08-20 13:15:26 -0700307#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
Kees Cook0aa5e492017-04-05 09:49:19 -0700308#endif
309
Mikael Pettersson9c695202010-06-29 15:05:25 -0700310#if !defined(__noclone)
311#define __noclone /* not needed */
312#endif
Borislav Petkovc837fb32011-03-22 16:33:55 -0700313
Andrey Ryabinind9764412015-10-19 11:37:17 +0300314#if !defined(__no_sanitize_address)
315#define __no_sanitize_address
316#endif
317
Borislav Petkovc837fb32011-03-22 16:33:55 -0700318/*
Arnd Bergmann8793bb72018-06-19 13:14:56 -0700319 * Turn individual warnings and errors on and off locally, depending
320 * on version.
321 */
322#define __diag_GCC(version, severity, s) \
323 __diag_GCC_ ## version(__diag_GCC_ ## severity s)
324
325/* Severity used in pragma directives */
326#define __diag_GCC_ignore ignored
327#define __diag_GCC_warn warning
328#define __diag_GCC_error error
329
Arnd Bergmann8793bb72018-06-19 13:14:56 -0700330#define __diag_str1(s) #s
331#define __diag_str(s) __diag_str1(s)
332#define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
Arnd Bergmann8793bb72018-06-19 13:14:56 -0700333
334#if GCC_VERSION >= 80000
335#define __diag_GCC_8(s) __diag(s)
336#else
337#define __diag_GCC_8(s)
338#endif