Ignoring the "correction" logic riprel_pre_xol() and riprel_post_xol()
are very similar but look quite differently.
1. Add the "UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX" check at the start
of riprel_pre_xol(), like the same check in riprel_post_xol().
2. Add the trivial scratch_reg() helper which returns the address of
scratch register pre_xol/post_xol need to change.
3. Change these functions to use the new helper and avoid copy-and-paste
under if/else branches.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
