livepatch: avoid relocations referencing ignored section symbols

livepatch: avoid relocations referencing ignored section symbols

Track whether symbols belong to ignored sections in order to avoid
applying relocations referencing those symbols. The address of such
symbols won't be resolved and thus the relocation will likely fail or
write garbage to the destination.

Return an error in that case, as leaving unresolved relocations would
lead to malfunctioning payload code.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Tested-by: Bjoern Doebel <doebel@amazon.de>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>