Edit File: compiler.h
#ifndef __LINUX_COMPILER_H #define __LINUX_COMPILER_H #ifndef __ASSEMBLY__ #ifdef __CHECKER__ # define __user __attribute__((noderef, address_space(1))) # define __kernel __attribute__((address_space(0))) # define __safe __attribute__((safe)) # define __force __attribute__((force)) # define __nocast __attribute__((nocast)) # define __iomem __attribute__((noderef, address_space(2))) # define __must_hold(x) __attribute__((context(x,1,1))) # define __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) # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0) # define __percpu __attribute__((noderef, address_space(3))) #ifdef CONFIG_SPARSE_RCU_POINTER # define __rcu __attribute__((noderef, address_space(4))) #else # define __rcu #endif extern void __chk_user_ptr(const volatile void __user *); extern void __chk_io_ptr(const volatile void __iomem *); #else # define __user # define __kernel # define __safe # define __force # define __nocast # define __iomem # define __chk_user_ptr(x) (void)0 # define __chk_io_ptr(x) (void)0 # define __builtin_warning(x, y...) (1) # define __must_hold(x) # define __acquires(x) # define __releases(x) # define __acquire(x) (void)0 # define __release(x) (void)0 # define __cond_lock(x,c) (c) # define __percpu # define __rcu #endif /* Indirect macros required for expanded argument pasting, eg. __LINE__. */ #define ___PASTE(a,b) a##b #define __PASTE(a,b) ___PASTE(a,b) #ifdef __KERNEL__ #ifdef __GNUC__ #include <linux/compiler-gcc.h> #endif #define notrace __attribute__((no_instrument_function)) /* Intel compiler defines __GNUC__. So we will overwrite implementations * coming from above header files here */ #ifdef __INTEL_COMPILER # include <linux/compiler-intel.h> #endif /* * Generic compiler-dependent macros required for kernel * build go below this comment. Actual compiler/compiler version * specific implementations come from the above header files */ struct ftrace_branch_data { const char *func; const char *file; unsigned line; union { struct { unsigned long correct; unsigned long incorrect; }; struct { unsigned long miss; unsigned long hit; }; unsigned long miss_hit[2]; }; }; /* * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code * to disable branch tracing on a per file basis. */ #if defined(CONFIG_TRACE_BRANCH_PROFILING) \ && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__) void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); #define likely_notrace(x) __builtin_expect(!!(x), 1) #define unlikely_notrace(x) __builtin_expect(!!(x), 0) #define __branch_check__(x, expect) ({ \ int ______r; \ static struct ftrace_branch_data \ __attribute__((__aligned__(4))) \ __attribute__((section("_ftrace_annotated_branch"))) \ ______f = { \ .func = __func__, \ .file = __FILE__, \ .line = __LINE__, \ }; \ ______r = likely_notrace(x); \ ftrace_likely_update(&______f, ______r, expect); \ ______r; \ }) /* * Using __builtin_constant_p(x) to ignore cases where the return * value is always the same. This idea is taken from a similar patch * written by Daniel Walker. */ # ifndef likely # define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1)) # endif # ifndef unlikely # define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0)) # endif #ifdef CONFIG_PROFILE_ALL_BRANCHES /* * "Define 'is'", Bill Clinton * "Define 'if'", Steven Rostedt */ #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) ) #define __trace_if(cond) \ if (__builtin_constant_p((cond)) ? !!(cond) : \ ({ \ int ______r; \ static struct ftrace_branch_data \ __attribute__((__aligned__(4))) \ __attribute__((section("_ftrace_branch"))) \ ______f = { \ .func = __func__, \ .file = __FILE__, \ .line = __LINE__, \ }; \ ______r = !!(cond); \ ______f.miss_hit[______r]++; \ ______r; \ })) #endif /* CONFIG_PROFILE_ALL_BRANCHES */ #else # define likely(x) __builtin_expect(!!(x), 1) # define unlikely(x) __builtin_expect(!!(x), 0) #endif /* Optimization barrier */ #ifndef barrier # define barrier() __memory_barrier() #endif #ifndef barrier_data # define barrier_data(ptr) barrier() #endif /* Unreachable code */ #ifndef unreachable # define unreachable() do { } while (1) #endif #ifndef RELOC_HIDE # define RELOC_HIDE(ptr, off) \ ({ unsigned long __ptr; \ __ptr = (unsigned long) (ptr); \ (typeof(ptr)) (__ptr + (off)); }) #endif #ifndef OPTIMIZER_HIDE_VAR #define OPTIMIZER_HIDE_VAR(var) barrier() #endif /* Not-quite-unique ID. */ #ifndef __UNIQUE_ID # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__) #endif #include <uapi/linux/types.h> #define __READ_ONCE_SIZE \ ({ \ switch (size) { \ case 1: *(__u8 *)res = *(volatile __u8 *)p; break; \ case 2: *(__u16 *)res = *(volatile __u16 *)p; break; \ case 4: *(__u32 *)res = *(volatile __u32 *)p; break; \ case 8: *(__u64 *)res = *(volatile __u64 *)p; break; \ default: \ barrier(); \ __builtin_memcpy((void *)res, (const void *)p, size); \ barrier(); \ } \ }) static __always_inline void __read_once_size(const volatile void *p, void *res, int size) { __READ_ONCE_SIZE; } #ifdef CONFIG_KASAN /* * This function is not 'inline' because __no_sanitize_address confilcts * with inlining. Attempt to inline it may cause a build failure. * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 * '__maybe_unused' allows us to avoid defined-but-not-used warnings. */ static __no_sanitize_address __maybe_unused void __read_once_size_nocheck(const volatile void *p, void *res, int size) { __READ_ONCE_SIZE; } #else static __always_inline void __read_once_size_nocheck(const volatile void *p, void *res, int size) { __READ_ONCE_SIZE; } #endif static __always_inline void __write_once_size(volatile void *p, void *res, int size) { switch (size) { case 1: *(volatile __u8 *)p = *(__u8 *)res; break; case 2: *(volatile __u16 *)p = *(__u16 *)res; break; case 4: *(volatile __u32 *)p = *(__u32 *)res; break; case 8: *(volatile __u64 *)p = *(__u64 *)res; break; default: barrier(); __builtin_memcpy((void *)p, (const void *)res, size); barrier(); } } /* * Prevent the compiler from merging or refetching reads or writes. The * compiler is also forbidden from reordering successive instances of * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the * compiler is aware of some particular ordering. One way to make the * compiler aware of ordering is to put the two invocations of READ_ONCE, * WRITE_ONCE or ACCESS_ONCE() in different C statements. * * In contrast to ACCESS_ONCE these two macros will also work on aggregate * data types like structs or unions. If the size of the accessed data * type exceeds the word size of the machine (e.g., 32 bits or 64 bits) * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a * compile-time warning. * * Their two major use cases are: (1) Mediating communication between * process-level code and irq/NMI handlers, all running on the same CPU, * and (2) Ensuring that the compiler does not fold, spindle, or otherwise * mutilate accesses that either do not require ordering or that interact * with an explicit memory barrier or atomic instruction that provides the * required ordering. */ #define __READ_ONCE(x, check) \ ({ \ union { typeof(x) __val; char __c[1]; } __u; \ if (check) \ __read_once_size(&(x), __u.__c, sizeof(x)); \ else \ __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ __u.__val; \ }) #define READ_ONCE(x) __READ_ONCE(x, 1) /* * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need * to hide memory access from KASAN. */ #define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0) #define WRITE_ONCE(x, val) \ ({ union { typeof(x) __val; char __c[1]; } __u = { .__val = (val) }; __write_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) #endif /* __KERNEL__ */ #endif /* __ASSEMBLY__ */ #ifdef __KERNEL__ /* * Allow us to mark functions as 'deprecated' and have gcc emit a nice * warning for each use, in hopes of speeding the functions removal. * Usage is: * int __deprecated foo(void) */ #ifndef __deprecated # define __deprecated /* unimplemented */ #endif #ifdef MODULE #define __deprecated_for_modules __deprecated #else #define __deprecated_for_modules #endif #ifndef __must_check #define __must_check #endif #ifndef CONFIG_ENABLE_MUST_CHECK #undef __must_check #define __must_check #endif #ifndef CONFIG_ENABLE_WARN_DEPRECATED #undef __deprecated #undef __deprecated_for_modules #define __deprecated #define __deprecated_for_modules #endif /* * Allow us to avoid 'defined but not used' warnings on functions and data, * as well as force them to be emitted to the assembly file. * * As of gcc 3.4, static functions that are not marked with attribute((used)) * may be elided from the assembly file. As of gcc 3.4, static data not so * marked will not be elided, but this may change in a future gcc version. * * NOTE: Because distributions shipped with a backported unit-at-a-time * compiler in gcc 3.3, we must define __used to be __attribute__((used)) * for gcc >=3.3 instead of 3.4. * * In prior versions of gcc, such functions and data would be emitted, but * would be warned about except with attribute((unused)). * * Mark functions that are referenced only in inline assembly as __used so * the code is emitted even though it appears to be unreferenced. */ #ifndef __used # define __used /* unimplemented */ #endif #ifndef __maybe_unused # define __maybe_unused /* unimplemented */ #endif #ifndef __always_unused # define __always_unused /* unimplemented */ #endif #ifndef noinline #define noinline #endif /* * Rather then using noinline to prevent stack consumption, use * noinline_for_stack instead. For documentation reasons. */ #define noinline_for_stack noinline #ifndef __always_inline #define __always_inline inline #endif #endif /* __KERNEL__ */ /* * From the GCC manual: * * Many functions do not examine any values except their arguments, * and have no effects except the return value. Basically this is * just slightly more strict class than the `pure' attribute above, * since function is not allowed to read global memory. * * Note that a function that has pointer arguments and examines the * data pointed to must _not_ be declared `const'. Likewise, a * function that calls a non-`const' function usually must not be * `const'. It does not make sense for a `const' function to return * `void'. */ #ifndef __attribute_const__ # define __attribute_const__ /* unimplemented */ #endif /* * Tell gcc if a function is cold. The compiler will assume any path * directly leading to the call is unlikely. */ #ifndef __cold #define __cold #endif /* Simple shorthand for a section definition */ #ifndef __section # define __section(S) __attribute__ ((__section__(#S))) #endif #ifndef __visible #define __visible #endif #ifndef __nostackprotector # define __nostackprotector #endif /* Are two types/vars the same type (ignoring qualifiers)? */ #ifndef __same_type # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) #endif /* Is this type a native word size -- useful for atomic operations */ #ifndef __native_word # define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) #endif /* 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) # define __compiletime_error_fallback(condition) \ do { ((void)sizeof(char[1 - 2 * condition])); } while (0) #else # define __compiletime_error_fallback(condition) do { } while (0) #endif #define __compiletime_assert(condition, msg, prefix, suffix) \ do { \ bool __cond = !(condition); \ extern void prefix ## suffix(void) __compiletime_error(msg); \ if (__cond) \ prefix ## suffix(); \ __compiletime_error_fallback(__cond); \ } while (0) #define _compiletime_assert(condition, msg, prefix, suffix) \ __compiletime_assert(condition, msg, prefix, suffix) /** * compiletime_assert - break build and emit msg if condition is false * @condition: a compile-time constant condition to check * @msg: a message to emit if condition is false * * In tradition of POSIX assert, this macro will break the build if the * supplied condition is *false*, emitting the supplied error message if the * compiler has support to do so. */ #define compiletime_assert(condition, msg) \ _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) #define compiletime_assert_atomic_type(t) \ compiletime_assert(__native_word(t), \ "Need native word sized stores/loads for atomicity.") /* * Prevent the compiler from merging or refetching accesses. The compiler * is also forbidden from reordering successive instances of ACCESS_ONCE(), * but only when the compiler is aware of some particular ordering. One way * to make the compiler aware of ordering is to put the two invocations of * ACCESS_ONCE() in different C statements. * * This macro does absolutely -nothing- to prevent the CPU from reordering, * merging, or refetching absolutely anything at any time. Its main intended * use is to mediate communication between process-level code and irq/NMI * handlers, all running on the same CPU. */ #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) /** * lockless_dereference() - safely load a pointer for later dereference * @p: The pointer to load * * Similar to rcu_dereference(), but for situations where the pointed-to * object's lifetime is managed by something other than RCU. That * "something other" might be reference counting or simple immortality. */ #define lockless_dereference(p) \ ({ \ typeof(p) _________p1 = ACCESS_ONCE(p); \ smp_read_barrier_depends(); /* Dependency order vs. p above. */ \ (_________p1); \ }) /* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */ #ifdef CONFIG_KPROBES # define __kprobes __attribute__((__section__(".kprobes.text"))) #else # define __kprobes #endif #endif /* __LINUX_COMPILER_H */