Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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/* Make the optimizer believe the variable can be manipulated arbitrarily. */
62#define OPTIMIZER_HIDE_VAR(var) \
63 __asm__ ("" : "=r" (var) : "0" (var))
64
65/*
66 * A trick to suppress uninitialized variable warning without generating any
67 * code
68 */
69#define uninitialized_var(x) x = x
70
71#ifdef RETPOLINE
72#define __noretpoline __attribute__((__indirect_branch__("keep")))
73#endif
74
75#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
76
77#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
78
79#define __compiletime_warning(message) __attribute__((__warning__(message)))
80#define __compiletime_error(message) __attribute__((__error__(message)))
81
82#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
83#define __latent_entropy __attribute__((latent_entropy))
84#endif
85
86/*
87 * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
88 * confuse the stack allocation in gcc, leading to overly large stack
89 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
90 *
91 * Adding an empty inline assembly before it works around the problem
92 */
93#define barrier_before_unreachable() asm volatile("")
94
95/*
96 * Mark a position in code as unreachable. This can be used to
97 * suppress control flow warnings after asm blocks that transfer
98 * control elsewhere.
99 */
100#define unreachable() \
101 do { \
102 annotate_unreachable(); \
103 barrier_before_unreachable(); \
104 __builtin_unreachable(); \
105 } while (0)
106
107#if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
108#define __randomize_layout __attribute__((randomize_layout))
109#define __no_randomize_layout __attribute__((no_randomize_layout))
110/* This anon struct can add padding, so only enable it under randstruct. */
111#define randomized_struct_fields_start struct {
112#define randomized_struct_fields_end } __randomize_layout;
113#endif
114
115/*
116 * GCC 'asm goto' miscompiles certain code sequences:
117 *
118 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
119 *
120 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
121 *
122 * (asm goto is automatically volatile - the naming reflects this.)
123 */
124#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
125
126/*
127 * sparse (__CHECKER__) pretends to be gcc, but can't do constant
128 * folding in __builtin_bswap*() (yet), so don't set these for it.
129 */
130#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
131#define __HAVE_BUILTIN_BSWAP32__
132#define __HAVE_BUILTIN_BSWAP64__
133#if GCC_VERSION >= 40800
134#define __HAVE_BUILTIN_BSWAP16__
135#endif
136#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
137
138#if GCC_VERSION >= 70000
139#define KASAN_ABI_VERSION 5
140#elif GCC_VERSION >= 50000
141#define KASAN_ABI_VERSION 4
142#elif GCC_VERSION >= 40902
143#define KASAN_ABI_VERSION 3
144#endif
145
146#if GCC_VERSION >= 50100
147#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
148#endif
149
150/*
151 * Turn individual warnings and errors on and off locally, depending
152 * on version.
153 */
154#define __diag_GCC(version, severity, s) \
155 __diag_GCC_ ## version(__diag_GCC_ ## severity s)
156
157/* Severity used in pragma directives */
158#define __diag_GCC_ignore ignored
159#define __diag_GCC_warn warning
160#define __diag_GCC_error error
161
162#define __diag_str1(s) #s
163#define __diag_str(s) __diag_str1(s)
164#define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
165
166#if GCC_VERSION >= 80000
167#define __diag_GCC_8(s) __diag(s)
168#else
169#define __diag_GCC_8(s)
170#endif