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

[Jessica Yu]

+++ Steven Rostedt [02/03/17 13:11 -0500]:
> Can I get an Ack from a module maintainer?

Acked-by: Jessica Yu <jeyu@xxxxxxxxxx>

Thanks!

Jessica

> On Wed,  1 Mar 2017 14:04:53 -0800
> David Daney <david.daney@xxxxxxxxxx> wrote:
>
> > 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)) }
> >  }