[PATCH] module: set __jump_table alignment to 8

From: David Daney
Date: Wed Mar 01 2017 - 17:06:25 EST


For powerpc the __jump_table section in modules is not aligned, this
causes a WARN_ON() splat when loading a module containing a __jump_table.

Strict alignment became necessary with commit 3821fd35b58d
("jump_label: Reduce the size of struct static_key"), currently in
linux-next, which uses the two least significant bits of pointers to
__jump_table elements.

Fix by forcing __jump_table to 8, which is the same alignment used for
this section in the kernel proper.

Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
Tested-by: Sachin Sant <sachinp@xxxxxxxxxxxxxxxxxx>
---
scripts/module-common.lds | 2 ++
1 file changed, 2 insertions(+)

diff --git a/scripts/module-common.lds b/scripts/module-common.lds
index 73a2c7d..53234e8 100644
--- a/scripts/module-common.lds
+++ b/scripts/module-common.lds
@@ -19,4 +19,6 @@ SECTIONS {

. = ALIGN(8);
.init_array 0 : { *(SORT(.init_array.*)) *(.init_array) }
+
+ __jump_table 0 : ALIGN(8) { KEEP(*(__jump_table)) }
}
--
2.9.3