x86, paravirt: Remove kmap_atomic_pte paravirt op.

Now that both Xen and VMI disable allocations of PTE pages from high
memory this paravirt op serves no further purpose.

This effectively reverts ce6234b5 "add kmap_atomic_pte for mapping
highpte pages".

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
LKML-Reference: <1267204562-11844-3-git-send-email-ian.campbell@citrix.com>
Acked-by: Alok Kataria <akataria@vmware.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/xen/mmu.c

@@ -1427,24 +1427,6 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
 #endif
 }
 
-#ifdef CONFIG_HIGHPTE
-static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
-{
-	pgprot_t prot = PAGE_KERNEL;
-
-	/*
-	 * We disable highmem allocations for page tables so we should never
-	 * see any calls to kmap_atomic_pte on a highmem page.
-	 */
-	BUG_ON(PageHighMem(page));
-
-	if (PagePinned(page))
-		prot = PAGE_KERNEL_RO;
-
-	return kmap_atomic_prot(page, type, prot);
-}
-#endif
-
 #ifdef CONFIG_X86_32
 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 {
@@ -1903,10 +1885,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initdata = {
 	.alloc_pmd_clone = paravirt_nop,
 	.release_pmd = xen_release_pmd_init,
 
-#ifdef CONFIG_HIGHPTE
-	.kmap_atomic_pte = xen_kmap_atomic_pte,
-#endif
-
 #ifdef CONFIG_X86_64
 	.set_pte = xen_set_pte,
 #else