1 files changed, 29 insertions, 3 deletions

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index dd852b73b286..10b8f23fab0f 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -307,10 +307,36 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
 #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
-#ifndef __linktime_error
-# define __linktime_error(message)
-#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__)
+
 /*
  * Prevent the compiler from merging or refetching accesses.  The compiler
  * is also forbidden from reordering successive instances of ACCESS_ONCE(),