1 files changed, 134 insertions, 0 deletions

diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
new file mode 100644
index 000000000000..f4b6124fdb75
--- /dev/null
+++ b/arch/s390/mm/hugetlbpage.c
@@ -0,0 +1,134 @@
+/*
+ *  IBM System z Huge TLB Page Support for Kernel.
+ *
+ *    Copyright 2007 IBM Corp.
+ *    Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+                                   pte_t *pteptr, pte_t pteval)
+{
+        pmd_t *pmdp = (pmd_t *) pteptr;
+        pte_t shadow_pteval = pteval;
+        unsigned long mask;
+
+        if (!MACHINE_HAS_HPAGE) {
+                pteptr = (pte_t *) pte_page(pteval)[1].index;
+                mask = pte_val(pteval) &
+                                (_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
+                pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) | mask;
+                if (mm->context.noexec) {
+                        pteptr += PTRS_PER_PTE;
+                        pte_val(shadow_pteval) =
+                                        (_SEGMENT_ENTRY + __pa(pteptr)) | mask;
+                }
+        }
+
+        pmd_val(*pmdp) = pte_val(pteval);
+        if (mm->context.noexec) {
+                pmdp = get_shadow_table(pmdp);
+                pmd_val(*pmdp) = pte_val(shadow_pteval);
+        }
+}
+
+int arch_prepare_hugepage(struct page *page)
+{
+        unsigned long addr = page_to_phys(page);
+        pte_t pte;
+        pte_t *ptep;
+        int i;
+
+        if (MACHINE_HAS_HPAGE)
+                return 0;
+
+        ptep = (pte_t *) pte_alloc_one(&init_mm, address);
+        if (!ptep)
+                return -ENOMEM;
+
+        pte = mk_pte(page, PAGE_RW);
+        for (i = 0; i < PTRS_PER_PTE; i++) {
+                set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte);
+                pte_val(pte) += PAGE_SIZE;
+        }
+        page[1].index = (unsigned long) ptep;
+        return 0;
+}
+
+void arch_release_hugepage(struct page *page)
+{
+        pte_t *ptep;
+
+        if (MACHINE_HAS_HPAGE)
+                return;
+
+        ptep = (pte_t *) page[1].index;
+        if (!ptep)
+                return;
+        pte_free(&init_mm, ptep);
+        page[1].index = 0;
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pgdp;
+        pud_t *pudp;
+        pmd_t *pmdp = NULL;
+
+        pgdp = pgd_offset(mm, addr);
+        pudp = pud_alloc(mm, pgdp, addr);
+        if (pudp)
+                pmdp = pmd_alloc(mm, pudp, addr);
+        return (pte_t *) pmdp;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pgdp;
+        pud_t *pudp;
+        pmd_t *pmdp = NULL;
+
+        pgdp = pgd_offset(mm, addr);
+        if (pgd_present(*pgdp)) {
+                pudp = pud_offset(pgdp, addr);
+                if (pud_present(*pudp))
+                        pmdp = pmd_offset(pudp, addr);
+        }
+        return (pte_t *) pmdp;
+}
+
+int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
+{
+        return 0;
+}
+
+struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
+                              int write)
+{
+        return ERR_PTR(-EINVAL);
+}
+
+int pmd_huge(pmd_t pmd)
+{
+        if (!MACHINE_HAS_HPAGE)
+                return 0;
+
+        return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE);
+}
+
+struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+                             pmd_t *pmdp, int write)
+{
+        struct page *page;
+
+        if (!MACHINE_HAS_HPAGE)
+                return NULL;
+
+        page = pmd_page(*pmdp);
+        if (page)
+                page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
+        return page;
+}