+static void free_transition_pgtable(struct kimage *image)
+{
+ free_page((unsigned long)image->arch.pud);
+ free_page((unsigned long)image->arch.pmd);
+ free_page((unsigned long)image->arch.pte);
+}
+
+static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
+{
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned long vaddr, paddr;
+ int result = -ENOMEM;
+
+ vaddr = (unsigned long)relocate_kernel;
+ paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
+ pgd += pgd_index(vaddr);
+ if (!pgd_present(*pgd)) {
+ pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
+ if (!pud)
+ goto err;
+ image->arch.pud = pud;
+ set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
+ }
+ pud = pud_offset(pgd, vaddr);
+ if (!pud_present(*pud)) {
+ pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
+ if (!pmd)
+ goto err;
+ image->arch.pmd = pmd;
+ set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
+ }
+ pmd = pmd_offset(pud, vaddr);
+ if (!pmd_present(*pmd)) {
+ pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
+ if (!pte)
+ goto err;
+ image->arch.pte = pte;
+ set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
+ }
+ pte = pte_offset_kernel(pmd, vaddr);
+ set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
+ return 0;
+err:
+ free_transition_pgtable(image);
+ return result;
+}
+