On Mon, 27 Feb 2017 13:41:13 -0800
David Daney [off-list ref] wrote:

On 02/27/2017 01:06 PM, Steven Rostedt wrote:

quoted

On Mon, 27 Feb 2017 11:59:50 -0800
David Daney [off-list ref] wrote:
 

quoted

For me the size is not the important issue, it is the alignment of the
struct jump_entry entries in the table.  I don't understand how your
patch helps, and I cannot Acked-by unless I understand what is being
done and can see that it is both correct and necessary.  

You brought up a very good point and I'm glad that I had Jason Cc all
the arch maintainers in one patch.

I think jump_labels may be much more broken than we think, and Jason's
fix doesn't fix anything. We had this same issues with tracepoints.

I'm looking at jump_label_init, and how we iterate over an array of
struct jump_entry's that was put together by the linker. The problem is
that jump_entry is not a power of 2 in size.
 

ELF sections may have an ENTSIZE property exactly for arrays.  Since 
each jump_entry will have a unique value they cannot be merged, but we 
can tell the assembler they are an array and get them properly packed. 
Perhaps something like (untested):

    .pushsection __jump_table,  \"awM\",@progbits,24
    FOO
    .popsection

And the linker will honor this too?

-- Steve