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-rw-r--r--arch/s390/mm/hugetlbpage.c212
1 files changed, 212 insertions, 0 deletions
diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
new file mode 100644
index 000000000..e617e74b7
--- /dev/null
+++ b/arch/s390/mm/hugetlbpage.c
@@ -0,0 +1,212 @@
+/*
+ * IBM System z Huge TLB Page Support for Kernel.
+ *
+ * Copyright IBM Corp. 2007
+ * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+
+static inline pmd_t __pte_to_pmd(pte_t pte)
+{
+ pmd_t pmd;
+
+ /*
+ * Convert encoding pte bits pmd bits
+ * lIR.uswrdy.p dy..R...I...wr
+ * empty 010.000000.0 -> 00..0...1...00
+ * prot-none, clean, old 111.000000.1 -> 00..1...1...00
+ * prot-none, clean, young 111.000001.1 -> 01..1...1...00
+ * prot-none, dirty, old 111.000010.1 -> 10..1...1...00
+ * prot-none, dirty, young 111.000011.1 -> 11..1...1...00
+ * read-only, clean, old 111.000100.1 -> 00..1...1...01
+ * read-only, clean, young 101.000101.1 -> 01..1...0...01
+ * read-only, dirty, old 111.000110.1 -> 10..1...1...01
+ * read-only, dirty, young 101.000111.1 -> 11..1...0...01
+ * read-write, clean, old 111.001100.1 -> 00..1...1...11
+ * read-write, clean, young 101.001101.1 -> 01..1...0...11
+ * read-write, dirty, old 110.001110.1 -> 10..0...1...11
+ * read-write, dirty, young 100.001111.1 -> 11..0...0...11
+ * HW-bits: R read-only, I invalid
+ * SW-bits: p present, y young, d dirty, r read, w write, s special,
+ * u unused, l large
+ */
+ if (pte_present(pte)) {
+ pmd_val(pmd) = pte_val(pte) & PAGE_MASK;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_READ) >> 4;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_WRITE) >> 4;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_INVALID) >> 5;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_PROTECT);
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_DIRTY) << 10;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_YOUNG) << 10;
+ } else
+ pmd_val(pmd) = _SEGMENT_ENTRY_INVALID;
+ return pmd;
+}
+
+static inline pte_t __pmd_to_pte(pmd_t pmd)
+{
+ pte_t pte;
+
+ /*
+ * Convert encoding pmd bits pte bits
+ * dy..R...I...wr lIR.uswrdy.p
+ * empty 00..0...1...00 -> 010.000000.0
+ * prot-none, clean, old 00..1...1...00 -> 111.000000.1
+ * prot-none, clean, young 01..1...1...00 -> 111.000001.1
+ * prot-none, dirty, old 10..1...1...00 -> 111.000010.1
+ * prot-none, dirty, young 11..1...1...00 -> 111.000011.1
+ * read-only, clean, old 00..1...1...01 -> 111.000100.1
+ * read-only, clean, young 01..1...0...01 -> 101.000101.1
+ * read-only, dirty, old 10..1...1...01 -> 111.000110.1
+ * read-only, dirty, young 11..1...0...01 -> 101.000111.1
+ * read-write, clean, old 00..1...1...11 -> 111.001100.1
+ * read-write, clean, young 01..1...0...11 -> 101.001101.1
+ * read-write, dirty, old 10..0...1...11 -> 110.001110.1
+ * read-write, dirty, young 11..0...0...11 -> 100.001111.1
+ * HW-bits: R read-only, I invalid
+ * SW-bits: p present, y young, d dirty, r read, w write, s special,
+ * u unused, l large
+ */
+ if (pmd_present(pmd)) {
+ pte_val(pte) = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN_LARGE;
+ pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_READ) << 4;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) << 4;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_INVALID) << 5;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT);
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY) >> 10;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_YOUNG) >> 10;
+ } else
+ pte_val(pte) = _PAGE_INVALID;
+ return pte;
+}
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte)
+{
+ pmd_t pmd;
+
+ pmd = __pte_to_pmd(pte);
+ if (!MACHINE_HAS_HPAGE) {
+ /* Emulated huge ptes loose the dirty and young bit */
+ pmd_val(pmd) &= ~_SEGMENT_ENTRY_ORIGIN;
+ pmd_val(pmd) |= pte_page(pte)[1].index;
+ } else
+ pmd_val(pmd) |= _SEGMENT_ENTRY_LARGE;
+ *(pmd_t *) ptep = pmd;
+}
+
+pte_t huge_ptep_get(pte_t *ptep)
+{
+ unsigned long origin;
+ pmd_t pmd;
+
+ pmd = *(pmd_t *) ptep;
+ if (!MACHINE_HAS_HPAGE && pmd_present(pmd)) {
+ origin = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN;
+ pmd_val(pmd) &= ~_SEGMENT_ENTRY_ORIGIN;
+ pmd_val(pmd) |= *(unsigned long *) origin;
+ /* Emulated huge ptes are young and dirty by definition */
+ pmd_val(pmd) |= _SEGMENT_ENTRY_YOUNG | _SEGMENT_ENTRY_DIRTY;
+ }
+ return __pmd_to_pte(pmd);
+}
+
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep)
+{
+ pmd_t *pmdp = (pmd_t *) ptep;
+ pte_t pte = huge_ptep_get(ptep);
+
+ pmdp_flush_direct(mm, addr, pmdp);
+ pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY;
+ return pte;
+}
+
+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, addr);
+ if (!ptep)
+ return -ENOMEM;
+
+ pte_val(pte) = addr;
+ 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;
+ clear_table((unsigned long *) ptep, _PAGE_INVALID,
+ PTRS_PER_PTE * sizeof(pte_t));
+ page_table_free(&init_mm, (unsigned long *) ptep);
+ page[1].index = 0;
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+ unsigned long addr, unsigned long sz)
+{
+ 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;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+ if (!MACHINE_HAS_HPAGE)
+ return 0;
+
+ return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE);
+}
+
+int pud_huge(pud_t pud)
+{
+ return 0;
+}