Re: [PATCH] module: set __jump_table alignment to 8

+++ David Daney [02/03/17 11:24 -0800]:

On 03/02/2017 10:26 AM, Jessica Yu wrote:

quoted

+++ Steven Rostedt [02/03/17 13:11 -0500]:

quoted

Can I get an Ack from a module maintainer?

Acked-by: Jessica Yu <redacted>

Thanks!

Jessica

Thanks Jessica,

Can you also add scripts/module-common.lds to MAINTAINERS so that 
get_maintainers.pl will indicate that Jessica Yu and Rusty Russell be 
CCed on things like this in the future?

Sure thing. Thanks for the heads up!

Jessica

quoted

quoted

On Wed,  1 Mar 2017 14:04:53 -0800
David Daney [off-list ref] wrote:

quoted

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 <redacted>
Tested-by: Sachin Sant <redacted>
---
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)) }

}