Initial import

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;
+}