Re: [PATCH RFC] ARM: option for loading modules into vmalloc area

[Nicolas Pitre]

On Wed, 19 Nov 2014, Russell King - ARM Linux wrote:

> On Wed, Nov 19, 2014 at 11:57:15AM -0500, Nicolas Pitre wrote:
> > On Wed, 19 Nov 2014, Russell King - ARM Linux wrote:
> > > I don't think I ever did, because its pretty much impossible to do as I
> > > explained in a follow up to this thread.
> > > 
> > > We _used_ to do this with the userspace insmod methods, but since we got
> > > this kernel-side linker, it's been pretty much impossible to do without
> > > rewriting the module code.  That's not going to happen on account of one
> > > quirky architecture which Linus doesn't particularly like.
> > 
> > Still... We could try adding a hook in the generic module linker code 
> > for a pre-relocation pass.  Maybe only ARM would use it, but if the need 
> > to load big modules is real then I imagine Linus could be amenable to a 
> > compromise.
> 
> So, how big a table would you allocate for the trampolines, based upon
> not knowing anything about the module being loaded?  4K?  8K?  64K?

The idea of a pre-relocation pass is to determine that.  That could be 
something similar to calling apply_relocate() twice: once to determine 
the number of trampoline entries, and a second time to perform the 
actual relocation.


Nicolas
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/