[PATCH] trigger a syntax error if percpu macros are incorrectly used

get_cpu_var()/per_cpu()/__get_cpu_var() arguments must be simple
identifiers.  Otherwise the arch dependent implementations might break.

This patch enforces the correct usage of the macros by producing a syntax
error if the variable is not a simple identifier.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 11 insertions, 9 deletions

diff --git a/include/asm-s390/percpu.h b/include/asm-s390/percpu.h
index 28b3517e787c..495ad99c7635 100644
--- a/include/asm-s390/percpu.h
+++ b/include/asm-s390/percpu.h
@@ -15,18 +15,20 @@
  */
 #if defined(__s390x__) && defined(MODULE)
 
-#define __reloc_hide(var,offset) \
-  (*({ unsigned long *__ptr; \
-       asm ( "larl %0,per_cpu__"#var"@GOTENT" \
-             : "=a" (__ptr) : "X" (per_cpu__##var) ); \
-       (typeof(&per_cpu__##var))((*__ptr) + (offset)); }))
+#define __reloc_hide(var,offset) (*({                   \
+        extern int simple_indentifier_##var(void);      \
+        unsigned long *__ptr;                           \
+        asm ( "larl %0,per_cpu__"#var"@GOTENT"          \
+            : "=a" (__ptr) : "X" (per_cpu__##var) );    \
+        (typeof(&per_cpu__##var))((*__ptr) + (offset)); }))
 
 #else
 
-#define __reloc_hide(var, offset) \
-  (*({ unsigned long __ptr; \
-       asm ( "" : "=a" (__ptr) : "0" (&per_cpu__##var) ); \
-       (typeof(&per_cpu__##var)) (__ptr + (offset)); }))
+#define __reloc_hide(var, offset) (*({                          \
+        extern int simple_indentifier_##var(void);              \
+        unsigned long __ptr;                                    \
+        asm ( "" : "=a" (__ptr) : "0" (&per_cpu__##var) );      \
+        (typeof(&per_cpu__##var)) (__ptr + (offset)); }))
 
 #endif