mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-29 18:19:02 +00:00
288 lines
9.9 KiB
Diff
288 lines
9.9 KiB
Diff
--- /dev/null
|
|
+++ b/include/linux/compiler-gcc7.h
|
|
@@ -0,0 +1,284 @@
|
|
+#ifndef __LINUX_COMPILER_H
|
|
+#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
|
|
+#endif
|
|
+
|
|
+/*
|
|
+ * Common definitions for all gcc versions go here.
|
|
+ */
|
|
+#define GCC_VERSION (__GNUC__ * 10000 \
|
|
+ + __GNUC_MINOR__ * 100 \
|
|
+ + __GNUC_PATCHLEVEL__)
|
|
+
|
|
+/* Optimization barrier */
|
|
+
|
|
+/* The "volatile" is due to gcc bugs */
|
|
+#define barrier() __asm__ __volatile__("": : :"memory")
|
|
+/*
|
|
+ * This version is i.e. to prevent dead stores elimination on @ptr
|
|
+ * where gcc and llvm may behave differently when otherwise using
|
|
+ * normal barrier(): while gcc behavior gets along with a normal
|
|
+ * barrier(), llvm needs an explicit input variable to be assumed
|
|
+ * clobbered. The issue is as follows: while the inline asm might
|
|
+ * access any memory it wants, the compiler could have fit all of
|
|
+ * @ptr into memory registers instead, and since @ptr never escaped
|
|
+ * from that, it proofed that the inline asm wasn't touching any of
|
|
+ * it. This version works well with both compilers, i.e. we're telling
|
|
+ * the compiler that the inline asm absolutely may see the contents
|
|
+ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
|
|
+ */
|
|
+#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
|
|
+
|
|
+/*
|
|
+ * This macro obfuscates arithmetic on a variable address so that gcc
|
|
+ * shouldn't recognize the original var, and make assumptions about it.
|
|
+ *
|
|
+ * This is needed because the C standard makes it undefined to do
|
|
+ * pointer arithmetic on "objects" outside their boundaries and the
|
|
+ * gcc optimizers assume this is the case. In particular they
|
|
+ * assume such arithmetic does not wrap.
|
|
+ *
|
|
+ * A miscompilation has been observed because of this on PPC.
|
|
+ * To work around it we hide the relationship of the pointer and the object
|
|
+ * using this macro.
|
|
+ *
|
|
+ * Versions of the ppc64 compiler before 4.1 had a bug where use of
|
|
+ * RELOC_HIDE could trash r30. The bug can be worked around by changing
|
|
+ * the inline assembly constraint from =g to =r, in this particular
|
|
+ * case either is valid.
|
|
+ */
|
|
+#define RELOC_HIDE(ptr, off) \
|
|
+({ \
|
|
+ unsigned long __ptr; \
|
|
+ __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
|
|
+ (typeof(ptr)) (__ptr + (off)); \
|
|
+})
|
|
+
|
|
+/* Make the optimizer believe the variable can be manipulated arbitrarily. */
|
|
+#define OPTIMIZER_HIDE_VAR(var) \
|
|
+ __asm__ ("" : "=r" (var) : "0" (var))
|
|
+
|
|
+#ifdef __CHECKER__
|
|
+#define __must_be_array(a) 0
|
|
+#else
|
|
+/* &a[0] degrades to a pointer: a different type from an array */
|
|
+#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
|
|
+#endif
|
|
+
|
|
+/*
|
|
+ * Force always-inline if the user requests it so via the .config,
|
|
+ * or if gcc is too old:
|
|
+ */
|
|
+#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
|
|
+ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
|
|
+#define inline inline __attribute__((always_inline)) notrace
|
|
+#define __inline__ __inline__ __attribute__((always_inline)) notrace
|
|
+#define __inline __inline __attribute__((always_inline)) notrace
|
|
+#else
|
|
+/* A lot of inline functions can cause havoc with function tracing */
|
|
+#define inline inline notrace
|
|
+#define __inline__ __inline__ notrace
|
|
+#define __inline __inline notrace
|
|
+#endif
|
|
+
|
|
+#define __always_inline inline __attribute__((always_inline))
|
|
+#define noinline __attribute__((noinline))
|
|
+
|
|
+#define __deprecated __attribute__((deprecated))
|
|
+#define __packed __attribute__((packed))
|
|
+#define __weak __attribute__((weak))
|
|
+#define __alias(symbol) __attribute__((alias(#symbol)))
|
|
+
|
|
+/*
|
|
+ * it doesn't make sense on ARM (currently the only user of __naked)
|
|
+ * to trace naked functions because then mcount is called without
|
|
+ * stack and frame pointer being set up and there is no chance to
|
|
+ * restore the lr register to the value before mcount was called.
|
|
+ *
|
|
+ * The asm() bodies of naked functions often depend on standard calling
|
|
+ * conventions, therefore they must be noinline and noclone.
|
|
+ *
|
|
+ * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
|
|
+ * See GCC PR44290.
|
|
+ */
|
|
+#define __naked __attribute__((naked)) noinline __noclone notrace
|
|
+
|
|
+#define __noreturn __attribute__((noreturn))
|
|
+
|
|
+/*
|
|
+ * From the GCC manual:
|
|
+ *
|
|
+ * Many functions have no effects except the return value and their
|
|
+ * return value depends only on the parameters and/or global
|
|
+ * variables. Such a function can be subject to common subexpression
|
|
+ * elimination and loop optimization just as an arithmetic operator
|
|
+ * would be.
|
|
+ * [...]
|
|
+ */
|
|
+#define __pure __attribute__((pure))
|
|
+#define __aligned(x) __attribute__((aligned(x)))
|
|
+#define __printf(a, b) __attribute__((format(printf, a, b)))
|
|
+#define __scanf(a, b) __attribute__((format(scanf, a, b)))
|
|
+#define __attribute_const__ __attribute__((__const__))
|
|
+#define __maybe_unused __attribute__((unused))
|
|
+#define __always_unused __attribute__((unused))
|
|
+
|
|
+/* gcc version specific checks */
|
|
+
|
|
+#if GCC_VERSION < 30200
|
|
+# error Sorry, your compiler is too old - please upgrade it.
|
|
+#endif
|
|
+
|
|
+#if GCC_VERSION < 30300
|
|
+# define __used __attribute__((__unused__))
|
|
+#else
|
|
+# define __used __attribute__((__used__))
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_GCOV_KERNEL
|
|
+# if GCC_VERSION < 30400
|
|
+# error "GCOV profiling support for gcc versions below 3.4 not included"
|
|
+# endif /* __GNUC_MINOR__ */
|
|
+#endif /* CONFIG_GCOV_KERNEL */
|
|
+
|
|
+#if GCC_VERSION >= 30400
|
|
+#define __must_check __attribute__((warn_unused_result))
|
|
+#define __malloc __attribute__((__malloc__))
|
|
+#endif
|
|
+
|
|
+#if GCC_VERSION >= 40000
|
|
+
|
|
+/* GCC 4.1.[01] miscompiles __weak */
|
|
+#ifdef __KERNEL__
|
|
+# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101
|
|
+# error Your version of gcc miscompiles the __weak directive
|
|
+# endif
|
|
+#endif
|
|
+
|
|
+#define __used __attribute__((__used__))
|
|
+#define __compiler_offsetof(a, b) \
|
|
+ __builtin_offsetof(a, b)
|
|
+
|
|
+#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
|
|
+# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
|
|
+#endif
|
|
+
|
|
+#if GCC_VERSION >= 40300
|
|
+/* Mark functions as cold. gcc will assume any path leading to a call
|
|
+ * to them will be unlikely. This means a lot of manual unlikely()s
|
|
+ * are unnecessary now for any paths leading to the usual suspects
|
|
+ * like BUG(), printk(), panic() etc. [but let's keep them for now for
|
|
+ * older compilers]
|
|
+ *
|
|
+ * Early snapshots of gcc 4.3 don't support this and we can't detect this
|
|
+ * in the preprocessor, but we can live with this because they're unreleased.
|
|
+ * Maketime probing would be overkill here.
|
|
+ *
|
|
+ * gcc also has a __attribute__((__hot__)) to move hot functions into
|
|
+ * a special section, but I don't see any sense in this right now in
|
|
+ * the kernel context
|
|
+ */
|
|
+#define __cold __attribute__((__cold__))
|
|
+
|
|
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
|
|
+
|
|
+#ifndef __CHECKER__
|
|
+# define __compiletime_warning(message) __attribute__((warning(message)))
|
|
+# define __compiletime_error(message) __attribute__((error(message)))
|
|
+#endif /* __CHECKER__ */
|
|
+#endif /* GCC_VERSION >= 40300 */
|
|
+
|
|
+#if GCC_VERSION >= 40500
|
|
+/*
|
|
+ * Mark a position in code as unreachable. This can be used to
|
|
+ * suppress control flow warnings after asm blocks that transfer
|
|
+ * control elsewhere.
|
|
+ *
|
|
+ * Early snapshots of gcc 4.5 don't support this and we can't detect
|
|
+ * this in the preprocessor, but we can live with this because they're
|
|
+ * unreleased. Really, we need to have autoconf for the kernel.
|
|
+ */
|
|
+#define unreachable() __builtin_unreachable()
|
|
+
|
|
+/* Mark a function definition as prohibited from being cloned. */
|
|
+#define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
|
|
+
|
|
+#endif /* GCC_VERSION >= 40500 */
|
|
+
|
|
+#if GCC_VERSION >= 40600
|
|
+/*
|
|
+ * When used with Link Time Optimization, gcc can optimize away C functions or
|
|
+ * variables which are referenced only from assembly code. __visible tells the
|
|
+ * optimizer that something else uses this function or variable, thus preventing
|
|
+ * this.
|
|
+ */
|
|
+#define __visible __attribute__((externally_visible))
|
|
+#endif
|
|
+
|
|
+
|
|
+#if GCC_VERSION >= 40900 && !defined(__CHECKER__)
|
|
+/*
|
|
+ * __assume_aligned(n, k): Tell the optimizer that the returned
|
|
+ * pointer can be assumed to be k modulo n. The second argument is
|
|
+ * optional (default 0), so we use a variadic macro to make the
|
|
+ * shorthand.
|
|
+ *
|
|
+ * Beware: Do not apply this to functions which may return
|
|
+ * ERR_PTRs. Also, it is probably unwise to apply it to functions
|
|
+ * returning extra information in the low bits (but in that case the
|
|
+ * compiler should see some alignment anyway, when the return value is
|
|
+ * massaged by 'flags = ptr & 3; ptr &= ~3;').
|
|
+ */
|
|
+#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
|
|
+#endif
|
|
+
|
|
+/*
|
|
+ * GCC 'asm goto' miscompiles certain code sequences:
|
|
+ *
|
|
+ * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
|
|
+ *
|
|
+ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
|
|
+ *
|
|
+ * (asm goto is automatically volatile - the naming reflects this.)
|
|
+ */
|
|
+#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
|
|
+
|
|
+#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
|
|
+#if GCC_VERSION >= 40400
|
|
+#define __HAVE_BUILTIN_BSWAP32__
|
|
+#define __HAVE_BUILTIN_BSWAP64__
|
|
+#endif
|
|
+#if GCC_VERSION >= 40800
|
|
+#define __HAVE_BUILTIN_BSWAP16__
|
|
+#endif
|
|
+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
|
|
+
|
|
+#if GCC_VERSION >= 50000
|
|
+#define KASAN_ABI_VERSION 4
|
|
+#elif GCC_VERSION >= 40902
|
|
+#define KASAN_ABI_VERSION 3
|
|
+#endif
|
|
+
|
|
+#if GCC_VERSION >= 40902
|
|
+/*
|
|
+ * Tell the compiler that address safety instrumentation (KASAN)
|
|
+ * should not be applied to that function.
|
|
+ * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
|
|
+ */
|
|
+#define __no_sanitize_address __attribute__((no_sanitize_address))
|
|
+#endif
|
|
+
|
|
+#endif /* gcc version >= 40000 specific checks */
|
|
+
|
|
+#if !defined(__noclone)
|
|
+#define __noclone /* not needed */
|
|
+#endif
|
|
+
|
|
+#if !defined(__no_sanitize_address)
|
|
+#define __no_sanitize_address
|
|
+#endif
|
|
+
|
|
+/*
|
|
+ * A trick to suppress uninitialized variable warning without generating any
|
|
+ * code
|
|
+ */
|
|
+#define uninitialized_var(x) x = x
|