compiler-clang.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef __LINUX_COMPILER_TYPES_H
  3#error "Please do not include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
  4#endif
  5
  6/* Compiler specific definitions for Clang compiler */
  7
  8/*
  9 * Clang prior to 17 is being silly and considers many __cleanup() variables
 10 * as unused (because they are, their sole purpose is to go out of scope).
 11 *
 12 * https://github.com/llvm/llvm-project/commit/877210faa447f4cc7db87812f8ed80e398fedd61
 13 */
 14#undef __cleanup
 15#define __cleanup(func) __maybe_unused __attribute__((__cleanup__(func)))
 16
 17/* all clang versions usable with the kernel support KASAN ABI version 5 */
 18#define KASAN_ABI_VERSION 5
 19
 20/*
 21 * Clang 22 added preprocessor macros to match GCC, in hopes of eventually
 22 * dropping __has_feature support for sanitizers:
 23 * https://github.com/llvm/llvm-project/commit/568c23bbd3303518c5056d7f03444dae4fdc8a9c
 24 * Create these macros for older versions of clang so that it is easy to clean
 25 * up once the minimum supported version of LLVM for building the kernel always
 26 * creates these macros.
 27 *
 28 * Note: Checking __has_feature(*_sanitizer) is only true if the feature is
 29 * enabled. Therefore it is not required to additionally check defined(CONFIG_*)
 30 * to avoid adding redundant attributes in other configurations.
 31 */
 32#if __has_feature(address_sanitizer) && !defined(__SANITIZE_ADDRESS__)
 33#define __SANITIZE_ADDRESS__
 34#endif
 35#if __has_feature(hwaddress_sanitizer) && !defined(__SANITIZE_HWADDRESS__)
 36#define __SANITIZE_HWADDRESS__
 37#endif
 38#if __has_feature(thread_sanitizer) && !defined(__SANITIZE_THREAD__)
 39#define __SANITIZE_THREAD__
 40#endif
 41
 42/*
 43 * Treat __SANITIZE_HWADDRESS__ the same as __SANITIZE_ADDRESS__ in the kernel.
 44 */
 45#ifdef __SANITIZE_HWADDRESS__
 46#define __SANITIZE_ADDRESS__
 47#endif
 48
 49#ifdef __SANITIZE_ADDRESS__
 50#define __no_sanitize_address \
 51		__attribute__((no_sanitize("address", "hwaddress")))
 52#else
 53#define __no_sanitize_address
 54#endif
 55
 56#ifdef __SANITIZE_THREAD__
 57#define __no_sanitize_thread \
 58		__attribute__((no_sanitize("thread")))
 59#else
 60#define __no_sanitize_thread
 61#endif
 62
 63#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP)
 64#define __HAVE_BUILTIN_BSWAP32__
 65#define __HAVE_BUILTIN_BSWAP64__
 66#define __HAVE_BUILTIN_BSWAP16__
 67#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
 68
 69#if __has_feature(undefined_behavior_sanitizer)
 70/* GCC does not have __SANITIZE_UNDEFINED__ */
 71#define __no_sanitize_undefined \
 72		__attribute__((no_sanitize("undefined")))
 73#else
 74#define __no_sanitize_undefined
 75#endif
 76
 77#if __has_feature(memory_sanitizer)
 78#define __SANITIZE_MEMORY__
 79/*
 80 * Unlike other sanitizers, KMSAN still inserts code into functions marked with
 81 * no_sanitize("kernel-memory"). Using disable_sanitizer_instrumentation
 82 * provides the behavior consistent with other __no_sanitize_ attributes,
 83 * guaranteeing that __no_sanitize_memory functions remain uninstrumented.
 84 */
 85#define __no_sanitize_memory __disable_sanitizer_instrumentation
 86
 87/*
 88 * The __no_kmsan_checks attribute ensures that a function does not produce
 89 * false positive reports by:
 90 *  - initializing all local variables and memory stores in this function;
 91 *  - skipping all shadow checks;
 92 *  - passing initialized arguments to this function's callees.
 93 */
 94#define __no_kmsan_checks __attribute__((no_sanitize("kernel-memory")))
 95#else
 96#define __no_sanitize_memory
 97#define __no_kmsan_checks
 98#endif
 99
100/*
101 * Support for __has_feature(coverage_sanitizer) was added in Clang 13 together
102 * with no_sanitize("coverage"). Prior versions of Clang support coverage
103 * instrumentation, but cannot be queried for support by the preprocessor.
104 */
105#if __has_feature(coverage_sanitizer)
106#define __no_sanitize_coverage __attribute__((no_sanitize("coverage")))
107#else
108#define __no_sanitize_coverage
109#endif
110
111/* Only Clang needs to disable the coverage sanitizer for kstack_erase. */
112#define __no_kstack_erase	__no_sanitize_coverage
113
114#if __has_feature(shadow_call_stack)
115# define __noscs	__attribute__((__no_sanitize__("shadow-call-stack")))
116#endif
117
118/*
119 * Turn individual warnings and errors on and off locally, depending
120 * on version.
121 */
122#define __diag_clang(version, severity, s) \
123	__diag_clang_ ## version(__diag_clang_ ## severity s)
124
125/* Severity used in pragma directives */
126#define __diag_clang_ignore	ignored
127#define __diag_clang_warn	warning
128#define __diag_clang_error	error
129
130#define __diag_str1(s)		#s
131#define __diag_str(s)		__diag_str1(s)
132#define __diag(s)		_Pragma(__diag_str(clang diagnostic s))
133
134#define __diag_clang_13(s)	__diag(s)
135
136#define __diag_ignore_all(option, comment) \
137	__diag_clang(13, ignore, option)
138
139/*
140 * clang has horrible behavior with "g" or "rm" constraints for asm
141 * inputs, turning them into something worse than "m". Avoid using
142 * constraints with multiple possible uses (but "ir" seems to be ok):
143 *
144 *	https://github.com/llvm/llvm-project/issues/20571
145 */
146#define ASM_INPUT_G "ir"
147#define ASM_INPUT_RM "r"
148#define ASM_OUTPUT_RM "=r"
149
150/*
151 * Declare compiler support for __typeof_unqual__() operator.
152 *
153 * Bindgen uses LLVM even if our C compiler is GCC, so we cannot
154 * rely on the auto-detected CONFIG_CC_HAS_TYPEOF_UNQUAL.
155 */
156#define CC_HAS_TYPEOF_UNQUAL (__clang_major__ > 19 || (__clang_major__ == 19 && __clang_minor__ > 0))