- /*
- * Try to workaround a bug (thanks to BenH)
- * Set unmapped entries to a scratch page instead of 0.
- * Any prefetches that hit unmapped entries won't get an bus abort
- * then.
- */
- scratch = get_zeroed_page(GFP_KERNEL);
- if (!scratch)
- panic("Cannot allocate iommu scratch page");
- gart_unmapped_entry = GPTE_ENCODE(__pa(scratch));
- for (i = EMERGENCY_PAGES; i < iommu_pages; i++)
- iommu_gatt_base[i] = gart_unmapped_entry;
-