diff options
Diffstat (limited to 'include/linux/compiler_types.h')
| -rw-r--r-- | include/linux/compiler_types.h | 343 |
1 files changed, 298 insertions, 45 deletions
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 4b33cb385f96..2b77d12e07b2 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -2,8 +2,29 @@ #ifndef __LINUX_COMPILER_TYPES_H #define __LINUX_COMPILER_TYPES_H +/* + * __has_builtin is supported on gcc >= 10, clang >= 3 and icc >= 21. + * In the meantime, to support gcc < 10, we implement __has_builtin + * by hand. + */ +#ifndef __has_builtin +#define __has_builtin(x) (0) +#endif + #ifndef __ASSEMBLY__ +/* + * Skipped when running bindgen due to a libclang issue; + * see https://github.com/rust-lang/rust-bindgen/issues/2244. + */ +#if defined(CONFIG_DEBUG_INFO_BTF) && defined(CONFIG_PAHOLE_HAS_BTF_TAG) && \ + __has_attribute(btf_type_tag) && !defined(__BINDGEN__) +# define BTF_TYPE_TAG(value) __attribute__((btf_type_tag(#value))) +#else +# define BTF_TYPE_TAG(value) /* nothing */ +#endif + +/* sparse defines __CHECKER__; see Documentation/dev-tools/sparse.rst */ #ifdef __CHECKER__ /* address spaces */ # define __kernel __attribute__((address_space(0))) @@ -11,11 +32,12 @@ # define __iomem __attribute__((noderef, address_space(__iomem))) # define __percpu __attribute__((noderef, address_space(__percpu))) # define __rcu __attribute__((noderef, address_space(__rcu))) -extern void __chk_user_ptr(const volatile void __user *); -extern void __chk_io_ptr(const volatile void __iomem *); +static inline void __chk_user_ptr(const volatile void __user *ptr) { } +static inline void __chk_io_ptr(const volatile void __iomem *ptr) { } /* context/locking */ # define __must_hold(x) __attribute__((context(x,1,1))) # define __acquires(x) __attribute__((context(x,0,1))) +# define __cond_acquires(x) __attribute__((context(x,0,-1))) # define __releases(x) __attribute__((context(x,1,0))) # define __acquire(x) __context__(x,1) # define __release(x) __context__(x,-1) @@ -32,16 +54,18 @@ extern void __chk_io_ptr(const volatile void __iomem *); # ifdef STRUCTLEAK_PLUGIN # define __user __attribute__((user)) # else -# define __user +# define __user BTF_TYPE_TAG(user) # endif # define __iomem -# define __percpu -# define __rcu +# define __percpu __percpu_qual BTF_TYPE_TAG(percpu) +# define __rcu BTF_TYPE_TAG(rcu) + # define __chk_user_ptr(x) (void)0 # define __chk_io_ptr(x) (void)0 /* context/locking */ # define __must_hold(x) # define __acquires(x) +# define __cond_acquires(x) # define __releases(x) # define __acquire(x) (void)0 # define __release(x) (void)0 @@ -64,11 +88,87 @@ extern void __chk_io_ptr(const volatile void __iomem *); /* Attributes */ #include <linux/compiler_attributes.h> +#if CONFIG_FUNCTION_ALIGNMENT > 0 +#define __function_aligned __aligned(CONFIG_FUNCTION_ALIGNMENT) +#else +#define __function_aligned +#endif + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute + * + * When -falign-functions=N is in use, we must avoid the cold attribute as + * GCC drops the alignment for cold functions. Worse, GCC can implicitly mark + * callees of cold functions as cold themselves, so it's not sufficient to add + * __function_aligned here as that will not ensure that callees are correctly + * aligned. + * + * See: + * + * https://lore.kernel.org/lkml/Y77%2FqVgvaJidFpYt@FVFF77S0Q05N + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c9 + */ +#if defined(CONFIG_CC_HAS_SANE_FUNCTION_ALIGNMENT) || (CONFIG_FUNCTION_ALIGNMENT == 0) +#define __cold __attribute__((__cold__)) +#else +#define __cold +#endif + +/* + * On x86-64 and arm64 targets, __preserve_most changes the calling convention + * of a function to make the code in the caller as unintrusive as possible. This + * convention behaves identically to the C calling convention on how arguments + * and return values are passed, but uses a different set of caller- and callee- + * saved registers. + * + * The purpose is to alleviates the burden of saving and recovering a large + * register set before and after the call in the caller. This is beneficial for + * rarely taken slow paths, such as error-reporting functions that may be called + * from hot paths. + * + * Note: This may conflict with instrumentation inserted on function entry which + * does not use __preserve_most or equivalent convention (if in assembly). Since + * function tracing assumes the normal C calling convention, where the attribute + * is supported, __preserve_most implies notrace. It is recommended to restrict + * use of the attribute to functions that should or already disable tracing. + * + * Optional: not supported by gcc. + * + * clang: https://clang.llvm.org/docs/AttributeReference.html#preserve-most + */ +#if __has_attribute(__preserve_most__) && (defined(CONFIG_X86_64) || defined(CONFIG_ARM64)) +# define __preserve_most notrace __attribute__((__preserve_most__)) +#else +# 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> -#elif defined(__INTEL_COMPILER) -#include <linux/compiler-intel.h> #elif defined(__GNUC__) /* The above compilers also define __GNUC__, so order is important here. */ #include <linux/compiler-gcc.h> @@ -110,12 +210,6 @@ struct ftrace_likely_data { unsigned long constant; }; -#ifdef CONFIG_ENABLE_MUST_CHECK -#define __must_check __attribute__((__warn_unused_result__)) -#else -#define __must_check -#endif - #if defined(CC_USING_HOTPATCH) #define notrace __attribute__((hotpatch(0, 0))) #elif defined(CC_USING_PATCHABLE_FUNCTION_ENTRY) @@ -132,8 +226,6 @@ struct ftrace_likely_data { */ #define __naked __attribute__((__naked__)) notrace -#define __compiler_offsetof(a, b) __builtin_offsetof(a, b) - /* * Prefer gnu_inline, so that extern inline functions do not emit an * externally visible function. This makes extern inline behave as per gnu89 @@ -174,6 +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 @@ -193,19 +291,112 @@ struct ftrace_likely_data { # define __no_kasan_or_inline __always_inline #endif -#define __no_kcsan __no_sanitize_thread #ifdef __SANITIZE_THREAD__ +/* + * Clang still emits instrumentation for __tsan_func_{entry,exit}() and builtin + * atomics even with __no_sanitize_thread (to avoid false positives in userspace + * ThreadSanitizer). The kernel's requirements are stricter and we really do not + * want any instrumentation with __no_kcsan. + * + * Therefore we add __disable_sanitizer_instrumentation where available to + * 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_INTEGER_WRAP +# define __signed_wrap __attribute__((no_sanitize("signed-integer-overflow"))) +#else +# define __signed_wrap +#endif + /* Section for code which can't be instrumented at all */ -#define noinstr \ - noinline notrace __attribute((__section__(".noinstr.text"))) \ - __no_kcsan __no_sanitize_address +#define __noinstr_section(section) \ + noinline notrace __attribute((__section__(section))) \ + __no_kcsan __no_sanitize_address __no_profile __no_sanitize_coverage \ + __no_sanitize_memory __signed_wrap + +#define noinstr __noinstr_section(".noinstr.text") + +/* + * The __cpuidle section is used twofold: + * + * 1) the original use -- identifying if a CPU is 'stuck' in idle state based + * on it's instruction pointer. See cpu_in_idle(). + * + * 2) supressing instrumentation around where cpuidle disables RCU; where the + * function isn't strictly required for #1, this is interchangeable with + * noinstr. + */ +#define __cpuidle __noinstr_section(".cpuidle.text") #endif /* __KERNEL__ */ @@ -220,15 +411,15 @@ struct ftrace_likely_data { # define __latent_entropy #endif -#ifndef __randomize_layout +#if defined(RANDSTRUCT) && !defined(__CHECKER__) +# define __randomize_layout __designated_init __attribute__((randomize_layout)) +# define __no_randomize_layout __attribute__((no_randomize_layout)) +/* This anon struct can add padding, so only enable it under randstruct. */ +# define randomized_struct_fields_start struct { +# define randomized_struct_fields_end } __randomize_layout; +#else # define __randomize_layout __designated_init -#endif - -#ifndef __no_randomize_layout # define __no_randomize_layout -#endif - -#ifndef randomized_struct_fields_start # define randomized_struct_fields_start # define randomized_struct_fields_end #endif @@ -237,8 +428,69 @@ struct ftrace_likely_data { # define __noscs #endif -#ifndef asm_volatile_goto -#define asm_volatile_goto(x...) asm goto(x) +#ifndef __nocfi +# define __nocfi +#endif + +/* + * Any place that could be marked with the "alloc_size" attribute is also + * a place to be marked with the "malloc" attribute, except those that may + * be performing a _reallocation_, as that may alias the existing pointer. + * For these, use __realloc_size(). + */ +#ifdef __alloc_size__ +# define __alloc_size(x, ...) __alloc_size__(x, ## __VA_ARGS__) __malloc +# define __realloc_size(x, ...) __alloc_size__(x, ## __VA_ARGS__) +#else +# define __alloc_size(x, ...) __malloc +# define __realloc_size(x, ...) +#endif + +/* + * 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) +#define __member_size(p) __builtin_dynamic_object_size(p, 1) +#else +#define __struct_size(p) __builtin_object_size(p, 0) +#define __member_size(p) __builtin_object_size(p, 1) +#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 + * + * We do it here by hand, because it doesn't hurt. + */ +#ifndef asm_goto_output +#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 @@ -247,10 +499,6 @@ struct ftrace_likely_data { #define asm_inline asm #endif -#ifndef __no_fgcse -# define __no_fgcse -#endif - /* Are two types/vars the same type (ignoring qualifiers)? */ #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) @@ -281,26 +529,27 @@ struct ftrace_likely_data { (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \ sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) -/* Compile time object size, -1 for unknown */ -#ifndef __compiletime_object_size -# define __compiletime_object_size(obj) -1 -#endif -#ifndef __compiletime_warning -# define __compiletime_warning(message) -#endif -#ifndef __compiletime_error -# define __compiletime_error(message) -#endif - #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 { \ - extern void prefix ## suffix(void) __compiletime_error(msg); \ + /* \ + * __noreturn is needed to give the compiler enough \ + * information to avoid certain possibly-uninitialized \ + * warnings (regardless of the build failing). \ + */ \ + __noreturn extern void prefix ## suffix(void) \ + __compiletime_error(msg); \ if (!(condition)) \ 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) \ @@ -341,4 +590,8 @@ struct ftrace_likely_data { #define __diag_error(compiler, version, option, comment) \ __diag_ ## compiler(version, error, option) +#ifndef __diag_ignore_all +#define __diag_ignore_all(option, comment) +#endif + #endif /* __LINUX_COMPILER_TYPES_H */ |