x86: Add a Kconfig option to turn the copy_from_user warnings into errors

For automated testing it is useful to have the option to turn
the warnings on copy_from_user() etc checks into errors:

 In function ‘copy_from_user’,
     inlined from ‘fd_copyin’ at drivers/block/floppy.c:3080,
     inlined from ‘fd_ioctl’ at drivers/block/floppy.c:3503:
   linux/arch/x86/include/asm/uaccess_32.h:213:
  error: call to ‘copy_from_user_overflow’ declared with attribute error:
  copy_from_user buffer size is not provably correct

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20091002075050.4e9f7641@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index f1709c1f9eae..77542c57e20a 100644
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -41,4 +41,5 @@
 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
 #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.h b/include/linux/compiler.h
index 950356311f12..88fd4b673cb4 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -273,6 +273,9 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
 #ifndef __compiletime_warning
 # define __compiletime_warning(message)
 #endif
+#ifndef __compiletime_error
+# define __compiletime_error(message)
+#endif
 
 /*
  * Prevent the compiler from merging or refetching accesses.  The compiler