[PATCH 4.9 075/148] module: set __jump_table alignment to 8

Greg Kroah-Hartman
2017-12-12T13:11:46Z

From: David Daney <david.daney@cavium.com>

[ Upstream commit ab42632156becd35d3884ee5c14da2bedbf3149a ]

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.

Link: http://lkml.kernel.org/r/20170301220453.4756-1-david.daney@cavium.com

Reviewed-by: Jason Baron <jbaron@akamai.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
scripts/module-common.lds | 2 ++
1 file changed, 2 insertions(+)

--- 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)) }
}