| /* |
| * 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) |
| { |
| int none, young, prot; |
| pmd_t pmd; |
| |
| /* |
| * Convert encoding pte bits pmd bits |
| * .IR...wrdytp ..R...I...y. |
| * empty .10...000000 -> ..0...1...0. |
| * prot-none, clean, old .11...000001 -> ..0...1...1. |
| * prot-none, clean, young .11...000101 -> ..1...1...1. |
| * prot-none, dirty, old .10...001001 -> ..0...1...1. |
| * prot-none, dirty, young .10...001101 -> ..1...1...1. |
| * read-only, clean, old .11...010001 -> ..1...1...0. |
| * read-only, clean, young .01...010101 -> ..1...0...1. |
| * read-only, dirty, old .11...011001 -> ..1...1...0. |
| * read-only, dirty, young .01...011101 -> ..1...0...1. |
| * read-write, clean, old .11...110001 -> ..0...1...0. |
| * read-write, clean, young .01...110101 -> ..0...0...1. |
| * read-write, dirty, old .10...111001 -> ..0...1...0. |
| * read-write, dirty, young .00...111101 -> ..0...0...1. |
| * Huge ptes are dirty by definition, a clean pte is made dirty |
| * by the conversion. |
| */ |
| if (pte_present(pte)) { |
| pmd_val(pmd) = pte_val(pte) & PAGE_MASK; |
| if (pte_val(pte) & _PAGE_INVALID) |
| pmd_val(pmd) |= _SEGMENT_ENTRY_INVALID; |
| none = (pte_val(pte) & _PAGE_PRESENT) && |
| !(pte_val(pte) & _PAGE_READ) && |
| !(pte_val(pte) & _PAGE_WRITE); |
| prot = (pte_val(pte) & _PAGE_PROTECT) && |
| !(pte_val(pte) & _PAGE_WRITE); |
| young = pte_val(pte) & _PAGE_YOUNG; |
| if (none || young) |
| pmd_val(pmd) |= _SEGMENT_ENTRY_YOUNG; |
| if (prot || (none && young)) |
| pmd_val(pmd) |= _SEGMENT_ENTRY_PROTECT; |
| } 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 |
| * ..R...I...y. .IR...wrdytp |
| * empty ..0...1...0. -> .10...000000 |
| * prot-none, old ..0...1...1. -> .10...001001 |
| * prot-none, young ..1...1...1. -> .10...001101 |
| * read-only, old ..1...1...0. -> .11...011001 |
| * read-only, young ..1...0...1. -> .01...011101 |
| * read-write, old ..0...1...0. -> .10...111001 |
| * read-write, young ..0...0...1. -> .00...111101 |
| * Huge ptes are dirty by definition |
| */ |
| if (pmd_present(pmd)) { |
| pte_val(pte) = _PAGE_PRESENT | _PAGE_LARGE | _PAGE_DIRTY | |
| (pmd_val(pmd) & PAGE_MASK); |
| if (pmd_val(pmd) & _SEGMENT_ENTRY_INVALID) |
| pte_val(pte) |= _PAGE_INVALID; |
| if (pmd_prot_none(pmd)) { |
| if (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT) |
| pte_val(pte) |= _PAGE_YOUNG; |
| } else { |
| pte_val(pte) |= _PAGE_READ; |
| if (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT) |
| pte_val(pte) |= _PAGE_PROTECT; |
| else |
| pte_val(pte) |= _PAGE_WRITE; |
| if (pmd_val(pmd) & _SEGMENT_ENTRY_YOUNG) |
| pte_val(pte) |= _PAGE_YOUNG; |
| } |
| } 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) { |
| pmd_val(pmd) &= ~_SEGMENT_ENTRY_ORIGIN; |
| pmd_val(pmd) |= pte_page(pte)[1].index; |
| } else |
| pmd_val(pmd) |= _SEGMENT_ENTRY_LARGE | _SEGMENT_ENTRY_CO; |
| *(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; |
| } |
| 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); |
| |
| if (MACHINE_HAS_IDTE) |
| __pmd_idte(addr, pmdp); |
| else |
| __pmd_csp(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; |
| } |
| |
| 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); |
| } |
| |
| int pud_huge(pud_t pud) |
| { |
| return 0; |
| } |
| |
| 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; |
| } |