compiler-gcc.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef __LINUX_COMPILER_TYPES_H
  3#error "Please do not 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/*
 14 * This macro obfuscates arithmetic on a variable address so that gcc
 15 * shouldn't recognize the original var, and make assumptions about it.
 16 *
 17 * This is needed because the C standard makes it undefined to do
 18 * pointer arithmetic on "objects" outside their boundaries and the
 19 * gcc optimizers assume this is the case. In particular they
 20 * assume such arithmetic does not wrap.
 21 *
 22 * A miscompilation has been observed because of this on PPC.
 23 * To work around it we hide the relationship of the pointer and the object
 24 * using this macro.
 25 *
 26 * Versions of the ppc64 compiler before 4.1 had a bug where use of
 27 * RELOC_HIDE could trash r30. The bug can be worked around by changing
 28 * the inline assembly constraint from =g to =r, in this particular
 29 * case either is valid.
 30 */
 31#define RELOC_HIDE(ptr, off)						\
 32({									\
 33	unsigned long __ptr;						\
 34	__asm__ ("" : "=r"(__ptr) : "0"(ptr));				\
 35	(typeof(ptr)) (__ptr + (off));					\
 36})
 37
 38#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
 39#define __latent_entropy __attribute__((latent_entropy))
 40#endif
 41
 42/*
 43 * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
 44 * confuse the stack allocation in gcc, leading to overly large stack
 45 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
 46 *
 47 * Adding an empty inline assembly before it works around the problem
 48 */
 49#define barrier_before_unreachable() asm volatile("")
 50
 51#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP)
 52#define __HAVE_BUILTIN_BSWAP32__
 53#define __HAVE_BUILTIN_BSWAP64__
 54#define __HAVE_BUILTIN_BSWAP16__
 55#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
 56
 57#if GCC_VERSION >= 70000
 58#define KASAN_ABI_VERSION 5
 59#else
 60#define KASAN_ABI_VERSION 4
 61#endif
 62
 63#ifdef CONFIG_SHADOW_CALL_STACK
 64#define __noscs __attribute__((__no_sanitize__("shadow-call-stack")))
 65#endif
 66
 67#ifdef __SANITIZE_HWADDRESS__
 68#define __no_sanitize_address __attribute__((__no_sanitize__("hwaddress")))
 69#else
 70#define __no_sanitize_address __attribute__((__no_sanitize_address__))
 71#endif
 72
 73#if defined(__SANITIZE_THREAD__)
 74#define __no_sanitize_thread __attribute__((__no_sanitize_thread__))
 75#else
 76#define __no_sanitize_thread
 77#endif
 78
 79#define __no_sanitize_undefined __attribute__((__no_sanitize_undefined__))
 80
 81/*
 82 * Only supported since gcc >= 12
 83 */
 84#if defined(CONFIG_KCOV) && __has_attribute(__no_sanitize_coverage__)
 85#define __no_sanitize_coverage __attribute__((__no_sanitize_coverage__))
 86#else
 87#define __no_sanitize_coverage
 88#endif
 89
 90/*
 91 * Treat __SANITIZE_HWADDRESS__ the same as __SANITIZE_ADDRESS__ in the kernel,
 92 * matching the defines used by Clang.
 93 */
 94#ifdef __SANITIZE_HWADDRESS__
 95#define __SANITIZE_ADDRESS__
 96#endif
 97
 98/*
 99 * GCC does not support KMSAN.
100 */
101#define __no_sanitize_memory
102#define __no_kmsan_checks
103
104/*
105 * Turn individual warnings and errors on and off locally, depending
106 * on version.
107 */
108#define __diag_GCC(version, severity, s) \
109	__diag_GCC_ ## version(__diag_GCC_ ## severity s)
110
111/* Severity used in pragma directives */
112#define __diag_GCC_ignore	ignored
113#define __diag_GCC_warn		warning
114#define __diag_GCC_error	error
115
116#define __diag_str1(s)		#s
117#define __diag_str(s)		__diag_str1(s)
118#define __diag(s)		_Pragma(__diag_str(GCC diagnostic s))
119
120#if GCC_VERSION >= 80000
121#define __diag_GCC_8(s)		__diag(s)
122#else
123#define __diag_GCC_8(s)
124#endif
125
126#define __diag_GCC_all(s)	__diag(s)
127
128#define __diag_ignore_all(option, comment) \
129	__diag(__diag_GCC_ignore option)
130
131/*
132 * Prior to 9.1, -Wno-alloc-size-larger-than (and therefore the "alloc_size"
133 * attribute) do not work, and must be disabled.
134 */
135#if GCC_VERSION < 90100
136#undef __alloc_size__
137#endif
138
139/*
140 * Declare compiler support for __typeof_unqual__() operator.
141 *
142 * Bindgen uses LLVM even if our C compiler is GCC, so we cannot
143 * rely on the auto-detected CONFIG_CC_HAS_TYPEOF_UNQUAL.
144 */
145#define CC_HAS_TYPEOF_UNQUAL (__GNUC__ >= 14)