Re: [PATCH] jump_label: align jump_entry table to at least 4-bytes

[David Daney]

On 02/27/2017 02:50 PM, Jason Baron wrote:
> On 02/27/2017 05:45 PM, David Daney wrote:
> > On 02/27/2017 02:36 PM, Steven Rostedt wrote:
> > > On Mon, 27 Feb 2017 14:21:21 -0800
> > > David Daney <ddaney@xxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > > See attached for mips.  It seems to do the right thing.
> > > >
> > > > I leave it as an exercise to the reader to fix the other architectures.
> > > >
> > > > Consult your own  binutils experts to verify that what I say is true.
> > >
> > > It may still just be safer to do the pointers instead. That way we
> > > don't need to worry about some strange arch or off by one binutils
> > > messing it up.
> >
> > Obviously it is your choice, but this is bog standard ELF linking.  In
> > theory even the arrays of power-of-2 sized objects should also supply an
> > entity size.  Think __ex_table and its ilk.
> >
> >
> > The benefit of supplying an entsize is that you don't have to change the
> > structure of the existing code and risk breaking something in the
> > process.
> >
> > David Daney
>
> Thanks for the suggestion! I would like to see if this resolves the ppc
> issue we had. I'm attaching a powerpc patch based on your suggestion.
> Hopefully, Sachin can try it.

If there are problems, you could try something like:


$ find . -name \*\.o | xargs mips64-octeon-linux-gnu-readelf -eW  | grep 
'File:\| __jump_table'
File: ./drivers/firmware/built-in.o
File: ./drivers/built-in.o
  [3249] __jump_table      PROGBITS        0000000000000000 1838c8 
0022c8 18 WAM  0   0  8
File: ./drivers/spi/built-in.o
  [82] __jump_table      PROGBITS        0000000000000000 008cb0 000048 
18 WAM  0   0  8
File: ./drivers/spi/spi-cavium-octeon.o
File: ./drivers/spi/spi-cavium.o
File: ./drivers/spi/spi.o
.
.
.

Look for files where the size of the __jump_table section is not a 
integer multiple of the entsize.



> Thanks,
>
> -Jason