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-rw-r--r--include/linux/compiler-gcc.h3
-rw-r--r--include/linux/compiler-intel.h7
-rw-r--r--include/linux/compiler.h4
3 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 24545cd90a25..02ae99e8e6d3 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -37,6 +37,9 @@
__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(arr) 0
#else
diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h
index dc1bd3dcf11f..5529c5239421 100644
--- a/include/linux/compiler-intel.h
+++ b/include/linux/compiler-intel.h
@@ -15,6 +15,7 @@
*/
#undef barrier
#undef RELOC_HIDE
+#undef OPTIMIZER_HIDE_VAR
#define barrier() __memory_barrier()
@@ -23,6 +24,12 @@
__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
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 92669cd182a6..a2329c5e6206 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -170,6 +170,10 @@ 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__)