diff options
Diffstat (limited to 'include/linux/compiler_types.h')
| -rw-r--r-- | include/linux/compiler_types.h | 125 |
1 files changed, 122 insertions, 3 deletions
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 2abaa3a825a9..2b77d12e07b2 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -57,7 +57,7 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { } # define __user BTF_TYPE_TAG(user) # endif # define __iomem -# define __percpu BTF_TYPE_TAG(percpu) +# define __percpu __percpu_qual BTF_TYPE_TAG(percpu) # define __rcu BTF_TYPE_TAG(rcu) # define __chk_user_ptr(x) (void)0 @@ -143,6 +143,29 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { } # define __preserve_most #endif +/* + * Annotating a function/variable with __retain tells the compiler to place + * the object in its own section and set the flag SHF_GNU_RETAIN. This flag + * instructs the linker to retain the object during garbage-cleanup or LTO + * phases. + * + * Note that the __used macro is also used to prevent functions or data + * being optimized out, but operates at the compiler/IR-level and may still + * allow unintended removal of objects during linking. + * + * Optional: only supported since gcc >= 11, clang >= 13 + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-retain-function-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#retain + */ +#if __has_attribute(__retain__) && \ + (defined(CONFIG_LD_DEAD_CODE_DATA_ELIMINATION) || \ + defined(CONFIG_LTO_CLANG)) +# define __retain __attribute__((__retain__)) +#else +# define __retain +#endif + /* Compiler specific macros. */ #ifdef __clang__ #include <linux/compiler-clang.h> @@ -243,6 +266,12 @@ struct ftrace_likely_data { #define noinline_for_stack noinline /* + * Use noinline_for_tracing for functions that should not be inlined. + * For tracing reasons. + */ +#define noinline_for_tracing noinline + +/* * Sanitizer helper attributes: Because using __always_inline and * __no_sanitize_* conflict, provide helper attributes that will either expand * to __no_sanitize_* in compilation units where instrumentation is enabled @@ -273,17 +302,77 @@ struct ftrace_likely_data { * disable all instrumentation. See Kconfig.kcsan where this is mandatory. */ # define __no_kcsan __no_sanitize_thread __disable_sanitizer_instrumentation +/* + * Type qualifier to mark variables where all data-racy accesses should be + * ignored by KCSAN. Note, the implementation simply marks these variables as + * volatile, since KCSAN will treat such accesses as "marked". + */ +# define __data_racy volatile # define __no_sanitize_or_inline __no_kcsan notrace __maybe_unused #else # define __no_kcsan +# define __data_racy +#endif + +#ifdef __SANITIZE_MEMORY__ +/* + * Similarly to KASAN and KCSAN, KMSAN loses function attributes of inlined + * functions, therefore disabling KMSAN checks also requires disabling inlining. + * + * __no_sanitize_or_inline effectively prevents KMSAN from reporting errors + * within the function and marks all its outputs as initialized. + */ +# define __no_sanitize_or_inline __no_kmsan_checks notrace __maybe_unused #endif #ifndef __no_sanitize_or_inline #define __no_sanitize_or_inline __always_inline #endif +/* + * Optional: only supported since gcc >= 15 + * Optional: only supported since clang >= 18 + * + * gcc: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 + * clang: https://github.com/llvm/llvm-project/pull/76348 + * + * __bdos on clang < 19.1.2 can erroneously return 0: + * https://github.com/llvm/llvm-project/pull/110497 + * + * __bdos on clang < 19.1.3 can be off by 4: + * https://github.com/llvm/llvm-project/pull/112636 + */ +#ifdef CONFIG_CC_HAS_COUNTED_BY +# define __counted_by(member) __attribute__((__counted_by__(member))) +#else +# define __counted_by(member) +#endif + +/* + * Optional: only supported since gcc >= 15 + * Optional: not supported by Clang + * + * gcc: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 + */ +#ifdef CONFIG_CC_HAS_MULTIDIMENSIONAL_NONSTRING +# define __nonstring_array __attribute__((__nonstring__)) +#else +# define __nonstring_array +#endif + +/* + * Apply __counted_by() when the Endianness matches to increase test coverage. + */ +#ifdef __LITTLE_ENDIAN +#define __counted_by_le(member) __counted_by(member) +#define __counted_by_be(member) +#else +#define __counted_by_le(member) +#define __counted_by_be(member) __counted_by(member) +#endif + /* Do not trap wrapping arithmetic within an annotated function. */ -#ifdef CONFIG_UBSAN_SIGNED_WRAP +#ifdef CONFIG_UBSAN_INTEGER_WRAP # define __signed_wrap __attribute__((no_sanitize("signed-integer-overflow"))) #else # define __signed_wrap @@ -360,6 +449,11 @@ struct ftrace_likely_data { /* * When the size of an allocated object is needed, use the best available * mechanism to find it. (For cases where sizeof() cannot be used.) + * + * Optional: only supported since gcc >= 12 + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html + * clang: https://clang.llvm.org/docs/LanguageExtensions.html#evaluating-object-size */ #if __has_builtin(__builtin_dynamic_object_size) #define __struct_size(p) __builtin_dynamic_object_size(p, 0) @@ -370,6 +464,16 @@ struct ftrace_likely_data { #endif /* + * Determine if an attribute has been applied to a variable. + * Using __annotated needs to check for __annotated being available, + * or negative tests may fail when annotation cannot be checked. For + * example, see the definition of __is_cstr(). + */ +#if __has_builtin(__builtin_has_attribute) +#define __annotated(var, attr) __builtin_has_attribute(var, attr) +#endif + +/* * Some versions of gcc do not mark 'asm goto' volatile: * * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103979 @@ -380,6 +484,15 @@ struct ftrace_likely_data { #define asm_goto_output(x...) asm volatile goto(x) #endif +/* + * Clang has trouble with constraints with multiple + * alternative behaviors (mainly "g" and "rm"). + */ +#ifndef ASM_INPUT_G + #define ASM_INPUT_G "g" + #define ASM_INPUT_RM "rm" +#endif + #ifdef CONFIG_CC_HAS_ASM_INLINE #define asm_inline asm __inline #else @@ -417,6 +530,12 @@ struct ftrace_likely_data { sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) #ifdef __OPTIMIZE__ +/* + * #ifdef __OPTIMIZE__ is only a good approximation; for instance "make + * CFLAGS_foo.o=-Og" defines __OPTIMIZE__, does not elide the conditional code + * and can break compilation with wrong error message(s). Combine with + * -U__OPTIMIZE__ when needed. + */ # define __compiletime_assert(condition, msg, prefix, suffix) \ do { \ /* \ @@ -430,7 +549,7 @@ struct ftrace_likely_data { prefix ## suffix(); \ } while (0) #else -# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0) +# define __compiletime_assert(condition, msg, prefix, suffix) ((void)(condition)) #endif #define _compiletime_assert(condition, msg, prefix, suffix) \ |