include/linux/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  * Note: Checking __has_feature(*_sanitizer) is only true if the feature is
  22  * enabled. Therefore it is not required to additionally check defined(CONFIG_*)
  23  * to avoid adding redundant attributes in other configurations.
  24  */
  25
  26 #if __has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer)
  27 /* Emulate GCC's __SANITIZE_ADDRESS__ flag */
  28 #define __SANITIZE_ADDRESS__
  29 #define __no_sanitize_address \
  30                 __attribute__((no_sanitize("address", "hwaddress")))
  31 #else
  32 #define __no_sanitize_address
  33 #endif
  34
  35 #if __has_feature(thread_sanitizer)
  36 /* emulate gcc's __SANITIZE_THREAD__ flag */
  37 #define __SANITIZE_THREAD__
  38 #define __no_sanitize_thread \
  39                 __attribute__((no_sanitize("thread")))
  40 #else
  41 #define __no_sanitize_thread
  42 #endif
  43
  44 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP)
  45 #define __HAVE_BUILTIN_BSWAP32__
  46 #define __HAVE_BUILTIN_BSWAP64__
  47 #define __HAVE_BUILTIN_BSWAP16__
  48 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
  49
  50 #if __has_feature(undefined_behavior_sanitizer)
  51 /* GCC does not have __SANITIZE_UNDEFINED__ */
  52 #define __no_sanitize_undefined \
  53                 __attribute__((no_sanitize("undefined")))
  54 #else
  55 #define __no_sanitize_undefined
  56 #endif
  57
  58 #if __has_feature(memory_sanitizer)
  59 #define __SANITIZE_MEMORY__
  60 /*
  61  * Unlike other sanitizers, KMSAN still inserts code into functions marked with
  62  * no_sanitize("kernel-memory"). Using disable_sanitizer_instrumentation
  63  * provides the behavior consistent with other __no_sanitize_ attributes,
  64  * guaranteeing that __no_sanitize_memory functions remain uninstrumented.
  65  */
  66 #define __no_sanitize_memory __disable_sanitizer_instrumentation
  67
  68 /*
  69  * The __no_kmsan_checks attribute ensures that a function does not produce
  70  * false positive reports by:
  71  *  - initializing all local variables and memory stores in this function;
  72  *  - skipping all shadow checks;
  73  *  - passing initialized arguments to this function's callees.
  74  */
  75 #define __no_kmsan_checks __attribute__((no_sanitize("kernel-memory")))
  76 #else
  77 #define __no_sanitize_memory
  78 #define __no_kmsan_checks
  79 #endif
  80
  81 /*
  82  * Support for __has_feature(coverage_sanitizer) was added in Clang 13 together
  83  * with no_sanitize("coverage"). Prior versions of Clang support coverage
  84  * instrumentation, but cannot be queried for support by the preprocessor.
  85  */
  86 #if __has_feature(coverage_sanitizer)
  87 #define __no_sanitize_coverage __attribute__((no_sanitize("coverage")))
  88 #else
  89 #define __no_sanitize_coverage
  90 #endif
  91
  92 #if __has_feature(shadow_call_stack)
  93 # define __noscs        __attribute__((__no_sanitize__("shadow-call-stack")))
  94 #endif
  95
  96 #if __has_feature(kcfi)
  97 /* Disable CFI checking inside a function. */
  98 #define __nocfi         __attribute__((__no_sanitize__("kcfi")))
  99 #endif
 100
 101 /*
 102  * Turn individual warnings and errors on and off locally, depending
 103  * on version.
 104  */
 105 #define __diag_clang(version, severity, s) \
 106         __diag_clang_ ## version(__diag_clang_ ## severity s)
 107
 108 /* Severity used in pragma directives */
 109 #define __diag_clang_ignore     ignored
 110 #define __diag_clang_warn       warning
 111 #define __diag_clang_error      error
 112
 113 #define __diag_str1(s)          #s
 114 #define __diag_str(s)           __diag_str1(s)
 115 #define __diag(s)               _Pragma(__diag_str(clang diagnostic s))
 116
 117 #define __diag_clang_13(s)      __diag(s)
 118
 119 #define __diag_ignore_all(option, comment) \
 120         __diag_clang(13, ignore, option)
 121
 122 /*
 123  * clang has horrible behavior with "g" or "rm" constraints for asm
 124  * inputs, turning them into something worse than "m". Avoid using
 125  * constraints with multiple possible uses (but "ir" seems to be ok):
 126  *
 127  *      https://github.com/llvm/llvm-project/issues/20571
 128  */
 129 #define ASM_INPUT_G "ir"
 130 #define ASM_INPUT_RM "r"