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  • #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 __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
    
    /* 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
    
    
    /* Clang compiler defines __GNUC__. So we will overwrite implementations
     * coming from above header files here
     */
    #ifdef __clang__
    #include <linux/compiler-clang.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
    
    /* 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
    
    
    #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
    
    
    /* 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(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)
    
    /*
     * Sparse complains of variable sized arrays due to the temporary variable in
     * __compiletime_assert. Unfortunately we can't just expand it out to make
     * sparse see a constant array size without breaking compiletime_assert on old
     * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
     */
    # ifndef __CHECKER__
    #  define __compiletime_error_fallback(condition) \
    	do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
    # endif
    #endif
    #ifndef __compiletime_error_fallback
    # define __compiletime_error_fallback(condition) do { } while (0)
    
    #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))
    
    
    /* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
    #ifdef CONFIG_KPROBES
    # define __kprobes	__attribute__((__section__(".kprobes.text")))
    # define nokprobe_inline	__always_inline
    #else
    # define __kprobes
    # define nokprobe_inline	inline
    #endif
    
    #endif /* __LINUX_COMPILER_H */