1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_COMPILER_TYPES_H
3 #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
7 * Common definitions for all gcc versions go here.
9 #define GCC_VERSION (__GNUC__ * 10000 \
10 + __GNUC_MINOR__ * 100 \
11 + __GNUC_PATCHLEVEL__)
13 #if GCC_VERSION < 40600
14 # error Sorry, your compiler is too old - please upgrade it.
15 #elif defined(CONFIG_ARM64) && GCC_VERSION < 50100
17 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
18 * https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
20 # error Sorry, your version of GCC is too old - please use 5.1 or newer.
24 * This macro obfuscates arithmetic on a variable address so that gcc
25 * shouldn't recognize the original var, and make assumptions about it.
27 * This is needed because the C standard makes it undefined to do
28 * pointer arithmetic on "objects" outside their boundaries and the
29 * gcc optimizers assume this is the case. In particular they
30 * assume such arithmetic does not wrap.
32 * A miscompilation has been observed because of this on PPC.
33 * To work around it we hide the relationship of the pointer and the object
36 * Versions of the ppc64 compiler before 4.1 had a bug where use of
37 * RELOC_HIDE could trash r30. The bug can be worked around by changing
38 * the inline assembly constraint from =g to =r, in this particular
39 * case either is valid.
41 #define RELOC_HIDE(ptr, off) \
43 unsigned long __ptr; \
44 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
45 (typeof(ptr)) (__ptr + (off)); \
49 * A trick to suppress uninitialized variable warning without generating any
52 #define uninitialized_var(x) x = x
55 #define __must_be_array(a) 0
57 /* &a[0] degrades to a pointer: a different type from an array */
58 #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
61 #ifdef CONFIG_RETPOLINE
62 #define __noretpoline __attribute__((indirect_branch("keep")))
65 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
67 #define __optimize(level) __attribute__((__optimize__(level)))
69 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
72 #define __compiletime_warning(message) __attribute__((warning(message)))
73 #define __compiletime_error(message) __attribute__((error(message)))
75 #ifdef LATENT_ENTROPY_PLUGIN
76 #define __latent_entropy __attribute__((latent_entropy))
78 #endif /* __CHECKER__ */
81 * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
82 * confuse the stack allocation in gcc, leading to overly large stack
83 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
85 * Adding an empty inline assembly before it works around the problem
87 #define barrier_before_unreachable() asm volatile("")
90 * Mark a position in code as unreachable. This can be used to
91 * suppress control flow warnings after asm blocks that transfer
94 * Early snapshots of gcc 4.5 don't support this and we can't detect
95 * this in the preprocessor, but we can live with this because they're
96 * unreleased. Really, we need to have autoconf for the kernel.
98 #define unreachable() \
100 annotate_unreachable(); \
101 barrier_before_unreachable(); \
102 __builtin_unreachable(); \
105 /* Mark a function definition as prohibited from being cloned. */
106 #define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
108 #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
109 #define __randomize_layout __attribute__((randomize_layout))
110 #define __no_randomize_layout __attribute__((no_randomize_layout))
111 /* This anon struct can add padding, so only enable it under randstruct. */
112 #define randomized_struct_fields_start struct {
113 #define randomized_struct_fields_end } __randomize_layout;
117 * When used with Link Time Optimization, gcc can optimize away C functions or
118 * variables which are referenced only from assembly code. __visible tells the
119 * optimizer that something else uses this function or variable, thus preventing
122 #define __visible __attribute__((externally_visible))
124 /* gcc version specific checks */
126 #if GCC_VERSION >= 40900 && !defined(__CHECKER__)
128 * __assume_aligned(n, k): Tell the optimizer that the returned
129 * pointer can be assumed to be k modulo n. The second argument is
130 * optional (default 0), so we use a variadic macro to make the
133 * Beware: Do not apply this to functions which may return
134 * ERR_PTRs. Also, it is probably unwise to apply it to functions
135 * returning extra information in the low bits (but in that case the
136 * compiler should see some alignment anyway, when the return value is
137 * massaged by 'flags = ptr & 3; ptr &= ~3;').
139 #define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
143 * GCC 'asm goto' miscompiles certain code sequences:
145 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
147 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
149 * (asm goto is automatically volatile - the naming reflects this.)
151 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
154 * sparse (__CHECKER__) pretends to be gcc, but can't do constant
155 * folding in __builtin_bswap*() (yet), so don't set these for it.
157 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
158 #define __HAVE_BUILTIN_BSWAP32__
159 #define __HAVE_BUILTIN_BSWAP64__
160 #if GCC_VERSION >= 40800
161 #define __HAVE_BUILTIN_BSWAP16__
163 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
165 #if GCC_VERSION >= 70000
166 #define KASAN_ABI_VERSION 5
167 #elif GCC_VERSION >= 50000
168 #define KASAN_ABI_VERSION 4
169 #elif GCC_VERSION >= 40902
170 #define KASAN_ABI_VERSION 3
173 #if GCC_VERSION >= 40902
175 * Tell the compiler that address safety instrumentation (KASAN)
176 * should not be applied to that function.
177 * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
179 #define __no_sanitize_address __attribute__((no_sanitize_address))
182 #if GCC_VERSION >= 50100
184 * Mark structures as requiring designated initializers.
185 * https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html
187 #define __designated_init __attribute__((designated_init))
188 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
191 #if GCC_VERSION >= 90100
192 #define __copy(symbol) __attribute__((__copy__(symbol)))
195 #if !defined(__noclone)
196 #define __noclone /* not needed */
199 #if !defined(__no_sanitize_address)
200 #define __no_sanitize_address
204 * Turn individual warnings and errors on and off locally, depending
207 #define __diag_GCC(version, severity, s) \
208 __diag_GCC_ ## version(__diag_GCC_ ## severity s)
210 /* Severity used in pragma directives */
211 #define __diag_GCC_ignore ignored
212 #define __diag_GCC_warn warning
213 #define __diag_GCC_error error
215 #define __diag_str1(s) #s
216 #define __diag_str(s) __diag_str1(s)
217 #define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
219 #if GCC_VERSION >= 80000
220 #define __diag_GCC_8(s) __diag(s)
222 #define __diag_GCC_8(s)