--- /dev/null
+From 9b2c282b348dfe966bbba967dc7a45ce817cce50 Mon Sep 17 00:00:00 2001
+From: Tom Rini <trini@konsulko.com>
+Date: Mon, 29 Feb 2016 11:34:15 -0500
+Subject: [PATCH] compiler*.h: sync include/linux/compiler*.h with Linux
+ 4.5-rc6
+
+Copy these from Linux v4.5-rc6 tag.
+
+This is needed so that we can keep up with newer gcc versions. Note
+that we don't have the uapi/ hierarchy from the kernel so continue to
+use <linux/types.h>
+
+Signed-off-by: Tom Rini <trini@konsulko.com>
+---
+ include/linux/compiler-gcc.h | 266 ++++++++++++++++++++++++++++++++++------
+ include/linux/compiler-gcc3.h | 21 ----
+ include/linux/compiler-gcc4.h | 63 ----------
+ include/linux/compiler-intel.h | 45 +++++++
+ include/linux/compiler.h | 270 +++++++++++++++++++++++++++++++++++++++--
+ 5 files changed, 534 insertions(+), 131 deletions(-)
+ delete mode 100644 include/linux/compiler-gcc3.h
+ delete mode 100644 include/linux/compiler-gcc4.h
+ create mode 100644 include/linux/compiler-intel.h
+
+diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
+index 9896e54..22ab246 100644
+--- a/include/linux/compiler-gcc.h
++++ b/include/linux/compiler-gcc.h
+@@ -5,11 +5,28 @@
+ /*
+ * 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
+@@ -29,41 +46,63 @@
+ * 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)); })
++#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(__builtin_types_compatible_p(typeof(a), typeof(&a[0])))
++#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) || \
++#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
+ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
+-# define inline inline __attribute__((always_inline))
+-# define __inline__ __inline__ __attribute__((always_inline))
+-# define __inline __inline __attribute__((always_inline))
++#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 __deprecated __attribute__((deprecated))
+-#ifndef __packed
+-# define __packed __attribute__((packed))
+-#endif
+-#define __weak __attribute__((weak))
++#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.
++ * 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)) notrace
++#define __naked __attribute__((naked)) noinline __noclone notrace
+
+-#define __noreturn __attribute__((noreturn))
++#define __noreturn __attribute__((noreturn))
+
+ /*
+ * From the GCC manual:
+@@ -75,19 +114,170 @@
+ * would be.
+ * [...]
+ */
+-#ifndef __pure
+-# define __pure __attribute__((pure))
+-#endif
+-#ifndef __aligned
+-# define __aligned(x) __attribute__((aligned(x)))
+-#endif
+-#define __printf(a,b) __attribute__((format(printf,a,b)))
+-#define noinline __attribute__((noinline))
+-#define __attribute_const__ __attribute__((__const__))
+-#define __maybe_unused __attribute__((unused))
+-#define __always_unused __attribute__((unused))
+-
+-#define __gcc_header(x) #x
+-#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
+-#define gcc_header(x) _gcc_header(x)
+-#include gcc_header(__GNUC__)
++#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))
++#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__))
++
++#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 || (defined(__powerpc__) && GCC_VERSION >= 40600)
++#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
+diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
+deleted file mode 100644
+index 2befe65..0000000
+--- a/include/linux/compiler-gcc3.h
++++ /dev/null
+@@ -1,21 +0,0 @@
+-#ifndef __LINUX_COMPILER_H
+-#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
+-#endif
+-
+-#if __GNUC_MINOR__ >= 3
+-# define __used __attribute__((__used__))
+-#else
+-# define __used __attribute__((__unused__))
+-#endif
+-
+-#if __GNUC_MINOR__ >= 4
+-#define __must_check __attribute__((warn_unused_result))
+-#endif
+-
+-/*
+- * A trick to suppress uninitialized variable warning without generating any
+- * code
+- */
+-#define uninitialized_var(x) x = x
+-
+-#define __always_inline inline __attribute__((always_inline))
+diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
+deleted file mode 100644
+index 27d11ca..0000000
+--- a/include/linux/compiler-gcc4.h
++++ /dev/null
+@@ -1,63 +0,0 @@
+-#ifndef __LINUX_COMPILER_H
+-#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
+-#endif
+-
+-/* GCC 4.1.[01] miscompiles __weak */
+-#ifdef __KERNEL__
+-# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
+-# error Your version of gcc miscompiles the __weak directive
+-# endif
+-#endif
+-
+-#define __used __attribute__((__used__))
+-#define __must_check __attribute__((warn_unused_result))
+-#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
+-#ifndef __always_inline
+-# define __always_inline inline __attribute__((always_inline))
+-#endif
+-
+-/*
+- * A trick to suppress uninitialized variable warning without generating any
+- * code
+- */
+-#define uninitialized_var(x) x = x
+-
+-#if __GNUC_MINOR__ >= 3
+-/* 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__))
+-
+-
+-#if __GNUC_MINOR__ >= 5
+-/*
+- * 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()
+-#endif
+-
+-#endif
+-
+-#if __GNUC_MINOR__ > 0
+-#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
+-#endif
+-#if __GNUC_MINOR__ >= 4
+-#define __compiletime_warning(message) __attribute__((warning(message)))
+-#define __compiletime_error(message) __attribute__((error(message)))
+-#endif
+diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h
+new file mode 100644
+index 0000000..d4c7113
+--- /dev/null
++++ b/include/linux/compiler-intel.h
+@@ -0,0 +1,45 @@
++#ifndef __LINUX_COMPILER_H
++#error "Please don't include <linux/compiler-intel.h> directly, include <linux/compiler.h> instead."
++#endif
++
++#ifdef __ECC
++
++/* Some compiler specific definitions are overwritten here
++ * for Intel ECC compiler
++ */
++
++#include <asm/intrinsics.h>
++
++/* Intel ECC compiler doesn't support gcc specific asm stmts.
++ * It uses intrinsics to do the equivalent things.
++ */
++#undef barrier
++#undef barrier_data
++#undef RELOC_HIDE
++#undef OPTIMIZER_HIDE_VAR
++
++#define barrier() __memory_barrier()
++#define barrier_data(ptr) barrier()
++
++#define RELOC_HIDE(ptr, off) \
++ ({ unsigned long __ptr; \
++ __ptr = (unsigned long) (ptr); \
++ (typeof(ptr)) (__ptr + (off)); })
++
++/* This should act as an optimization barrier on var.
++ * Given that this compiler does not have inline assembly, a compiler barrier
++ * is the best we can do.
++ */
++#define OPTIMIZER_HIDE_VAR(var) barrier()
++
++/* Intel ECC compiler doesn't support __builtin_types_compatible_p() */
++#define __must_be_array(a) 0
++
++#endif
++
++#ifndef __HAVE_BUILTIN_BSWAP16__
++/* icc has this, but it's called _bswap16 */
++#define __HAVE_BUILTIN_BSWAP16__
++#define __builtin_bswap16 _bswap16
++#endif
++
+diff --git a/include/linux/compiler.h b/include/linux/compiler.h
+index 5be3dab..020ad16 100644
+--- a/include/linux/compiler.h
++++ b/include/linux/compiler.h
+@@ -5,16 +5,24 @@
+
+ #ifdef __CHECKER__
+ # define __user __attribute__((noderef, address_space(1)))
+-# define __kernel /* default address space */
++# 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)))
++# define __pmem __attribute__((noderef, address_space(5)))
++#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
+@@ -27,20 +35,32 @@ extern void __chk_io_ptr(const volatile void __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
++# define __pmem
+ #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
+
++#if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__)
++#define notrace __attribute__((hotpatch(0,0)))
++#else
+ #define notrace __attribute__((no_instrument_function))
++#endif
+
+ /* Intel compiler defines __GNUC__. So we will overwrite implementations
+ * coming from above header files here
+@@ -49,6 +69,13 @@ extern void __chk_io_ptr(const volatile void __iomem *);
+ # 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
+@@ -117,7 +144,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ */
+ #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
+ #define __trace_if(cond) \
+- if (__builtin_constant_p((cond)) ? !!(cond) : \
++ if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
+ ({ \
+ int ______r; \
+ static struct ftrace_branch_data \
+@@ -144,6 +171,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ # define barrier() __memory_barrier()
+ #endif
+
++#ifndef barrier_data
++# define barrier_data(ptr) barrier()
++#endif
++
+ /* Unreachable code */
+ #ifndef unreachable
+ # define unreachable() do { } while (1)
+@@ -156,6 +187,135 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ (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 <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)); \
++ __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 = (__force typeof(x)) (val) }; \
++ __write_once_size(&(x), __u.__c, sizeof(x)); \
++ __u.__val; \
++})
++
++/**
++ * smp_cond_acquire() - Spin wait for cond with ACQUIRE ordering
++ * @cond: boolean expression to wait for
++ *
++ * Equivalent to using smp_load_acquire() on the condition variable but employs
++ * the control dependency of the wait to reduce the barrier on many platforms.
++ *
++ * The control dependency provides a LOAD->STORE order, the additional RMB
++ * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order,
++ * aka. ACQUIRE.
++ */
++#define smp_cond_acquire(cond) do { \
++ while (!(cond)) \
++ cpu_relax(); \
++ smp_rmb(); /* ctrl + rmb := acquire */ \
++} while (0)
++
+ #endif /* __KERNEL__ */
+
+ #endif /* __ASSEMBLY__ */
+@@ -228,7 +388,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+
+ /*
+ * Rather then using noinline to prevent stack consumption, use
+- * noinline_for_stack instead. For documentaiton reasons.
++ * noinline_for_stack instead. For documentation reasons.
+ */
+ #define noinline_for_stack noinline
+
+@@ -270,11 +430,28 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ # define __section(S) __attribute__ ((__section__(#S)))
+ #endif
+
++#ifndef __visible
++#define __visible
++#endif
++
++/*
++ * Assume alignment of return value.
++ */
++#ifndef __assume_aligned
++#define __assume_aligned(a, ...)
++#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
+@@ -284,7 +461,48 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ #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)
++#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
+@@ -293,11 +511,45 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ * 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.
++ * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
++ * on a union member will work as long as the size of the member matches the
++ * size of the union and the size is smaller than word size.
++ *
++ * The major use cases of ACCESS_ONCE used to be (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.
++ *
++ * If possible use READ_ONCE()/WRITE_ONCE() instead.
+ */
+-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
+-
++#define __ACCESS_ONCE(x) ({ \
++ __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
++ (volatile typeof(x) *)&(x); })
++#define ACCESS_ONCE(x) (*__ACCESS_ONCE(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 = READ_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")))
++# define nokprobe_inline __always_inline
++#else
++# define __kprobes
++# define nokprobe_inline inline
++#endif
+ #endif /* __LINUX_COMPILER_H */
+--
+2.7.4
+
projects / openwrt / staging / noltari.git / commitdiff