287 lines
9.9 KiB
Diff
287 lines
9.9 KiB
Diff
--- /dev/null
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+++ b/include/linux/compiler-gcc7.h
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@@ -0,0 +1,284 @@
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+#ifndef __LINUX_COMPILER_H
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+#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
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+#endif
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+
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+/*
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+ * Common definitions for all gcc versions go here.
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+ */
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+#define GCC_VERSION (__GNUC__ * 10000 \
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+ + __GNUC_MINOR__ * 100 \
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+ + __GNUC_PATCHLEVEL__)
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+
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+/* Optimization barrier */
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+
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+/* The "volatile" is due to gcc bugs */
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+#define barrier() __asm__ __volatile__("": : :"memory")
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+/*
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+ * This version is i.e. to prevent dead stores elimination on @ptr
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+ * where gcc and llvm may behave differently when otherwise using
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+ * normal barrier(): while gcc behavior gets along with a normal
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+ * barrier(), llvm needs an explicit input variable to be assumed
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+ * clobbered. The issue is as follows: while the inline asm might
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+ * access any memory it wants, the compiler could have fit all of
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+ * @ptr into memory registers instead, and since @ptr never escaped
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+ * from that, it proofed that the inline asm wasn't touching any of
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+ * it. This version works well with both compilers, i.e. we're telling
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+ * the compiler that the inline asm absolutely may see the contents
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+ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
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+ */
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+#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
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+
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+/*
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+ * This macro obfuscates arithmetic on a variable address so that gcc
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+ * shouldn't recognize the original var, and make assumptions about it.
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+ *
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+ * This is needed because the C standard makes it undefined to do
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+ * pointer arithmetic on "objects" outside their boundaries and the
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+ * gcc optimizers assume this is the case. In particular they
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+ * assume such arithmetic does not wrap.
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+ *
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+ * A miscompilation has been observed because of this on PPC.
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+ * To work around it we hide the relationship of the pointer and the object
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+ * using this macro.
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+ *
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+ * Versions of the ppc64 compiler before 4.1 had a bug where use of
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+ * RELOC_HIDE could trash r30. The bug can be worked around by changing
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+ * the inline assembly constraint from =g to =r, in this particular
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+ * case either is valid.
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+ */
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+#define RELOC_HIDE(ptr, off) \
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+({ \
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+ unsigned long __ptr; \
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+ __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
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+ (typeof(ptr)) (__ptr + (off)); \
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+})
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+
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+/* Make the optimizer believe the variable can be manipulated arbitrarily. */
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+#define OPTIMIZER_HIDE_VAR(var) \
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+ __asm__ ("" : "=r" (var) : "0" (var))
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+
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+#ifdef __CHECKER__
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+#define __must_be_array(a) 0
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+#else
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+/* &a[0] degrades to a pointer: a different type from an array */
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+#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
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+#endif
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+
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+/*
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+ * Force always-inline if the user requests it so via the .config,
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+ * or if gcc is too old:
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+ */
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+#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
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+ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
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+#define inline inline __attribute__((always_inline)) notrace
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+#define __inline__ __inline__ __attribute__((always_inline)) notrace
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+#define __inline __inline __attribute__((always_inline)) notrace
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+#else
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+/* A lot of inline functions can cause havoc with function tracing */
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+#define inline inline notrace
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+#define __inline__ __inline__ notrace
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+#define __inline __inline notrace
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+#endif
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+
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+#define __always_inline inline __attribute__((always_inline))
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+#define noinline __attribute__((noinline))
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+
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+#define __deprecated __attribute__((deprecated))
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+#define __packed __attribute__((packed))
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+#define __weak __attribute__((weak))
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+#define __alias(symbol) __attribute__((alias(#symbol)))
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+
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+/*
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+ * it doesn't make sense on ARM (currently the only user of __naked)
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+ * to trace naked functions because then mcount is called without
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+ * stack and frame pointer being set up and there is no chance to
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+ * restore the lr register to the value before mcount was called.
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+ *
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+ * The asm() bodies of naked functions often depend on standard calling
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+ * conventions, therefore they must be noinline and noclone.
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+ *
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+ * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
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+ * See GCC PR44290.
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+ */
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+#define __naked __attribute__((naked)) noinline __noclone notrace
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+
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+#define __noreturn __attribute__((noreturn))
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+
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+/*
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+ * From the GCC manual:
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+ *
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+ * Many functions have no effects except the return value and their
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+ * return value depends only on the parameters and/or global
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+ * variables. Such a function can be subject to common subexpression
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+ * elimination and loop optimization just as an arithmetic operator
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+ * would be.
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+ * [...]
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+ */
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+#define __pure __attribute__((pure))
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+#define __aligned(x) __attribute__((aligned(x)))
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+#define __printf(a, b) __attribute__((format(printf, a, b)))
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+#define __scanf(a, b) __attribute__((format(scanf, a, b)))
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+#define __attribute_const__ __attribute__((__const__))
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+#define __maybe_unused __attribute__((unused))
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+#define __always_unused __attribute__((unused))
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+
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+/* gcc version specific checks */
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+
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+#if GCC_VERSION < 30200
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+# error Sorry, your compiler is too old - please upgrade it.
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+#endif
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+
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+#if GCC_VERSION < 30300
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+# define __used __attribute__((__unused__))
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+#else
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+# define __used __attribute__((__used__))
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+#endif
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+
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+#ifdef CONFIG_GCOV_KERNEL
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+# if GCC_VERSION < 30400
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+# error "GCOV profiling support for gcc versions below 3.4 not included"
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+# endif /* __GNUC_MINOR__ */
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+#endif /* CONFIG_GCOV_KERNEL */
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+
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+#if GCC_VERSION >= 30400
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+#define __must_check __attribute__((warn_unused_result))
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+#define __malloc __attribute__((__malloc__))
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+#endif
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+
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+#if GCC_VERSION >= 40000
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+
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+/* GCC 4.1.[01] miscompiles __weak */
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+#ifdef __KERNEL__
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+# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101
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+# error Your version of gcc miscompiles the __weak directive
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+# endif
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+#endif
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+
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+#define __used __attribute__((__used__))
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+#define __compiler_offsetof(a, b) \
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+ __builtin_offsetof(a, b)
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+
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+#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
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+# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
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+#endif
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+
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+#if GCC_VERSION >= 40300
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+/* Mark functions as cold. gcc will assume any path leading to a call
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+ * to them will be unlikely. This means a lot of manual unlikely()s
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+ * are unnecessary now for any paths leading to the usual suspects
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+ * like BUG(), printk(), panic() etc. [but let's keep them for now for
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+ * older compilers]
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+ *
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+ * Early snapshots of gcc 4.3 don't support this and we can't detect this
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+ * in the preprocessor, but we can live with this because they're unreleased.
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+ * Maketime probing would be overkill here.
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+ *
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+ * gcc also has a __attribute__((__hot__)) to move hot functions into
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+ * a special section, but I don't see any sense in this right now in
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+ * the kernel context
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+ */
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+#define __cold __attribute__((__cold__))
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+
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+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
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+
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+#ifndef __CHECKER__
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+# define __compiletime_warning(message) __attribute__((warning(message)))
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+# define __compiletime_error(message) __attribute__((error(message)))
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+#endif /* __CHECKER__ */
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+#endif /* GCC_VERSION >= 40300 */
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+
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+#if GCC_VERSION >= 40500
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+/*
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+ * Mark a position in code as unreachable. This can be used to
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+ * suppress control flow warnings after asm blocks that transfer
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+ * control elsewhere.
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+ *
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+ * Early snapshots of gcc 4.5 don't support this and we can't detect
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+ * this in the preprocessor, but we can live with this because they're
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+ * unreleased. Really, we need to have autoconf for the kernel.
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+ */
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+#define unreachable() __builtin_unreachable()
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+
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+/* Mark a function definition as prohibited from being cloned. */
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+#define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
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+
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+#endif /* GCC_VERSION >= 40500 */
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+
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+#if GCC_VERSION >= 40600
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+/*
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+ * When used with Link Time Optimization, gcc can optimize away C functions or
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+ * variables which are referenced only from assembly code. __visible tells the
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+ * optimizer that something else uses this function or variable, thus preventing
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+ * this.
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+ */
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+#define __visible __attribute__((externally_visible))
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+#endif
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+
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+
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+#if GCC_VERSION >= 40900 && !defined(__CHECKER__)
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+/*
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+ * __assume_aligned(n, k): Tell the optimizer that the returned
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+ * pointer can be assumed to be k modulo n. The second argument is
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+ * optional (default 0), so we use a variadic macro to make the
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+ * shorthand.
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+ *
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+ * Beware: Do not apply this to functions which may return
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+ * ERR_PTRs. Also, it is probably unwise to apply it to functions
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+ * returning extra information in the low bits (but in that case the
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+ * compiler should see some alignment anyway, when the return value is
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+ * massaged by 'flags = ptr & 3; ptr &= ~3;').
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+ */
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+#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
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+#endif
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+
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+/*
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+ * GCC 'asm goto' miscompiles certain code sequences:
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+ *
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+ * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
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+ *
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+ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
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+ *
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+ * (asm goto is automatically volatile - the naming reflects this.)
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+ */
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+#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
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+
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+#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
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+#if GCC_VERSION >= 40400
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+#define __HAVE_BUILTIN_BSWAP32__
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+#define __HAVE_BUILTIN_BSWAP64__
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+#endif
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+#if GCC_VERSION >= 40800
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+#define __HAVE_BUILTIN_BSWAP16__
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+#endif
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+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
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+
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+#if GCC_VERSION >= 50000
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+#define KASAN_ABI_VERSION 4
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+#elif GCC_VERSION >= 40902
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+#define KASAN_ABI_VERSION 3
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+#endif
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+
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+#if GCC_VERSION >= 40902
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+/*
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+ * Tell the compiler that address safety instrumentation (KASAN)
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+ * should not be applied to that function.
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+ * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
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+ */
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+#define __no_sanitize_address __attribute__((no_sanitize_address))
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+#endif
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+
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+#endif /* gcc version >= 40000 specific checks */
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+
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+#if !defined(__noclone)
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+#define __noclone /* not needed */
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+#endif
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+
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+#if !defined(__no_sanitize_address)
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+#define __no_sanitize_address
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+#endif
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+
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+/*
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+ * A trick to suppress uninitialized variable warning without generating any
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+ * code
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+ */
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+#define uninitialized_var(x) x = x
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