The patch titled
Subject: kernel.h: Add BUILD_BUG() macro.
has been added to the -mm tree. Its filename is
kernelh-add-build_bug-macro-v3.patch
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From: David Daney <david.daney@xxxxxxxxxx>
Subject: kernel.h: Add BUILD_BUG() macro.
We can place this in definitions that we expect the compiler to remove
by dead code elimination. If this assertion fails, we get a nice
error message at build time.
The GCC function attribute error("message") was added in version 4.3,
so we define a new macro __linktime_error(message) to expand to this
for GCC-4.3 and later. This will give us an error diagnostic from the
compiler on the line that fails. For other compilers
__linktime_error(message) expands to nothing, and we have to be
content with a link time error, but at least we will still get a build
error.
BUILD_BUG() expands to the undefined function __build_bug_failed() and
will fail at link time if the compiler ever emits code for it. On
GCC-4.3 and later, attribute((error())) is used so that the failure
will be noted at compile time instead.
Acked-by: David Howells <dhowells@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: DM <dm.n9107@xxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kernel.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN include/linux/kernel.h~kernelh-add-build_bug-macro-v3 include/linux/kernel.h
--- a/include/linux/kernel.h~kernelh-add-build_bug-macro-v3
+++ a/include/linux/kernel.h
@@ -709,7 +709,7 @@ extern int __build_bug_on_failed;
* BUILD_BUG - break compile if used.
*
* If you have some code that you expect the compiler to eliminate at
- * build time, you should use BUILD_BUG_ON_USED to detect if it is
+ * build time, you should use BUILD_BUG to detect if it is
* unexpectedly used.
*/
#define BUILD_BUG() \
_
Subject: Subject: kernel.h: Add BUILD_BUG() macro.
Patches currently in -mm which might be from david.daney@xxxxxxxxxx are
linux-next.patch
kernelh-add-build_bug-macro.patch
kernelh-add-build_bug-macro-v3.patch
hugetlb-replace-bug-with-build_bug-for-dummy-definitions.patch
fs-binfmt_elf-create-kconfig-variable-for-pie-randomization.patch
mips-randomize-pie-load-address.patch
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