packet: Use symmetric hash for PACKET_FANOUT_HASH.

[firefly-linux-kernel-4.4.55.git] / include / linux / compiler-gcc.h

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 8efb40e61d6e48021d68f93635eea8d3ab3e8c0b..eeae401a2412e5e8d32381805be1c13798b7a8fb 100644 (file)
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -199,17 +199,37 @@
 #define unreachable() __builtin_unreachable()
 
 /* Mark a function definition as prohibited from being cloned. */
-#define __noclone      __attribute__((__noclone__))
+#define __noclone      __attribute__((__noclone__, __optimize__("no-tracer")))
 
 #endif /* GCC_VERSION >= 40500 */
 
 #if GCC_VERSION >= 40600
 /*
- * Tell the optimizer that something else uses this function or variable.
+ * 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:
  *