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."
4 #endif
5
6 /*
7 * Common definitions for all gcc versions go here.
8 */
9 #define GCC_VERSION (__GNUC__ * 10000 \
10 + __GNUC_MINOR__ * 100 \
11 + __GNUC_PATCHLEVEL__)
12
13 #if GCC_VERSION < 40600
14 # error Sorry, your compiler is too old - please upgrade it.
15 #endif
16
17 /* Optimization barrier */
18
19 /* The "volatile" is due to gcc bugs */
20 #define barrier() __asm__ __volatile__("": : :"memory")
21 /*
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
29 * from that, it proved that the inline asm wasn't touching any of
30 * 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")
35
36 /*
37 * 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 *
49 * 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 */
54 #define RELOC_HIDE(ptr, off) \
55 ({ \
56 unsigned long __ptr; \
57 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
58 (typeof(ptr)) (__ptr + (off)); \
59 })
60
61 /*
62 * A trick to suppress uninitialized variable warning without generating any
63 * code
64 */
65 #define uninitialized_var(x) x = x
66
67 #ifdef CONFIG_RETPOLINE
68 #define __noretpoline __attribute__((__indirect_branch__("keep")))
69 #endif
70
71 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
72
73 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
74
75 #define __compiletime_warning(message) __attribute__((__warning__(message)))
76 #define __compiletime_error(message) __attribute__((__error__(message)))
77
78 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
79 #define __latent_entropy __attribute__((latent_entropy))
80 #endif
81
82 /*
83 * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
84 * confuse the stack allocation in gcc, leading to overly large stack
85 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
86 *
87 * Adding an empty inline assembly before it works around the problem
88 */
89 #define barrier_before_unreachable() asm volatile("")
90
91 /*
92 * Mark a position in code as unreachable. This can be used to
93 * suppress control flow warnings after asm blocks that transfer
94 * control elsewhere.
95 */
96 #define unreachable() \
97 do { \
98 annotate_unreachable(); \
99 barrier_before_unreachable(); \
100 __builtin_unreachable(); \
101 } while (0)
102
103 #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
104 #define __randomize_layout __attribute__((randomize_layout))
105 #define __no_randomize_layout __attribute__((no_randomize_layout))
106 /* This anon struct can add padding, so only enable it under randstruct. */
107 #define randomized_struct_fields_start struct {
108 #define randomized_struct_fields_end } __randomize_layout;
109 #endif
110
111 /*
112 * GCC 'asm goto' miscompiles certain code sequences:
113 *
114 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
115 *
116 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
117 *
118 * (asm goto is automatically volatile - the naming reflects this.)
119 */
120 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
121
122 /*
123 * sparse (__CHECKER__) pretends to be gcc, but can't do constant
124 * folding in __builtin_bswap*() (yet), so don't set these for it.
125 */
126 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
127 #define __HAVE_BUILTIN_BSWAP32__
128 #define __HAVE_BUILTIN_BSWAP64__
129 #if GCC_VERSION >= 40800
130 #define __HAVE_BUILTIN_BSWAP16__
131 #endif
132 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
133
134 #if GCC_VERSION >= 70000
135 #define KASAN_ABI_VERSION 5
136 #elif GCC_VERSION >= 50000
137 #define KASAN_ABI_VERSION 4
138 #elif GCC_VERSION >= 40902
139 #define KASAN_ABI_VERSION 3
140 #endif
141
142 #if __has_attribute(__no_sanitize_address__)
143 #define __no_sanitize_address __attribute__((no_sanitize_address))
144 #else
145 #define __no_sanitize_address
146 #endif
147
148 #if GCC_VERSION >= 50100
149 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
150 #endif
151
152 /*
153 * Turn individual warnings and errors on and off locally, depending
154 * on version.
155 */
156 #define __diag_GCC(version, severity, s) \
157 __diag_GCC_ ## version(__diag_GCC_ ## severity s)
158
159 /* Severity used in pragma directives */
160 #define __diag_GCC_ignore ignored
161 #define __diag_GCC_warn warning
162 #define __diag_GCC_error error
163
164 #define __diag_str1(s) #s
165 #define __diag_str(s) __diag_str1(s)
166 #define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
167
168 #if GCC_VERSION >= 80000
169 #define __diag_GCC_8(s) __diag(s)
170 #else
171 #define __diag_GCC_8(s)
172 #endif
173
174 #define __no_fgcse __attribute__((optimize("-fno-gcse")))