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")))
175