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152125b7a8
The large segment table entry format has block of bits for the ACC/F values for the large page. These bits are valid only if another bit (AV bit 0x10000) of the segment table entry is set. The ACC/F bits do not have a meaning if the AV bit is off. This allows to put the THP splitting bit, the segment young bit and the new segment dirty bit into the ACC/F bits as long as the AV bit stays off. The dirty and young information is only available if the pmd is large. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
227 lines
5.9 KiB
C
227 lines
5.9 KiB
C
/*
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* IBM System z Huge TLB Page Support for Kernel.
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*
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* Copyright IBM Corp. 2007
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* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
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*/
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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static inline pmd_t __pte_to_pmd(pte_t pte)
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{
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pmd_t pmd;
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/*
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* Convert encoding pte bits pmd bits
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* .IR...wrdytp dy..R...I...wr
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* empty .10...000000 -> 00..0...1...00
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* prot-none, clean, old .11...000001 -> 00..1...1...00
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* prot-none, clean, young .11...000101 -> 01..1...1...00
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* prot-none, dirty, old .10...001001 -> 10..1...1...00
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* prot-none, dirty, young .10...001101 -> 11..1...1...00
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* read-only, clean, old .11...010001 -> 00..1...1...01
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* read-only, clean, young .01...010101 -> 01..1...0...01
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* read-only, dirty, old .11...011001 -> 10..1...1...01
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* read-only, dirty, young .01...011101 -> 11..1...0...01
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* read-write, clean, old .11...110001 -> 00..0...1...11
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* read-write, clean, young .01...110101 -> 01..0...0...11
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* read-write, dirty, old .10...111001 -> 10..0...1...11
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* read-write, dirty, young .00...111101 -> 11..0...0...11
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*/
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if (pte_present(pte)) {
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pmd_val(pmd) = pte_val(pte) & PAGE_MASK;
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pmd_val(pmd) |= (pte_val(pte) & _PAGE_READ) >> 4;
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pmd_val(pmd) |= (pte_val(pte) & _PAGE_WRITE) >> 4;
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pmd_val(pmd) |= (pte_val(pte) & _PAGE_INVALID) >> 5;
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pmd_val(pmd) |= (pte_val(pte) & _PAGE_PROTECT);
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pmd_val(pmd) |= (pte_val(pte) & _PAGE_DIRTY) << 10;
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pmd_val(pmd) |= (pte_val(pte) & _PAGE_YOUNG) << 10;
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} else
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pmd_val(pmd) = _SEGMENT_ENTRY_INVALID;
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return pmd;
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}
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static inline pte_t __pmd_to_pte(pmd_t pmd)
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{
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pte_t pte;
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/*
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* Convert encoding pmd bits pte bits
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* dy..R...I...wr .IR...wrdytp
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* empty 00..0...1...00 -> .10...001100
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* prot-none, clean, old 00..0...1...00 -> .10...000001
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* prot-none, clean, young 01..0...1...00 -> .10...000101
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* prot-none, dirty, old 10..0...1...00 -> .10...001001
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* prot-none, dirty, young 11..0...1...00 -> .10...001101
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* read-only, clean, old 00..1...1...01 -> .11...010001
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* read-only, clean, young 01..1...1...01 -> .11...010101
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* read-only, dirty, old 10..1...1...01 -> .11...011001
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* read-only, dirty, young 11..1...1...01 -> .11...011101
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* read-write, clean, old 00..0...1...11 -> .10...110001
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* read-write, clean, young 01..0...1...11 -> .10...110101
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* read-write, dirty, old 10..0...1...11 -> .10...111001
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* read-write, dirty, young 11..0...1...11 -> .10...111101
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*/
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if (pmd_present(pmd)) {
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pte_val(pte) = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN_LARGE;
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pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT;
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pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_READ) << 4;
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pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) << 4;
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pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_INVALID) << 5;
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pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT);
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pmd_val(pmd) |= (pte_val(pte) & _PAGE_DIRTY) << 10;
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pmd_val(pmd) |= (pte_val(pte) & _PAGE_YOUNG) << 10;
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} else
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pte_val(pte) = _PAGE_INVALID;
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return pte;
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}
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void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pte)
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{
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pmd_t pmd;
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pmd = __pte_to_pmd(pte);
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if (!MACHINE_HAS_HPAGE) {
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/* Emulated huge ptes loose the dirty and young bit */
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pmd_val(pmd) &= ~_SEGMENT_ENTRY_ORIGIN;
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pmd_val(pmd) |= pte_page(pte)[1].index;
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} else
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pmd_val(pmd) |= _SEGMENT_ENTRY_LARGE | _SEGMENT_ENTRY_CO;
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*(pmd_t *) ptep = pmd;
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}
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pte_t huge_ptep_get(pte_t *ptep)
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{
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unsigned long origin;
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pmd_t pmd;
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pmd = *(pmd_t *) ptep;
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if (!MACHINE_HAS_HPAGE && pmd_present(pmd)) {
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origin = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN;
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pmd_val(pmd) &= ~_SEGMENT_ENTRY_ORIGIN;
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pmd_val(pmd) |= *(unsigned long *) origin;
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/* Emulated huge ptes are young and dirty by definition */
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pmd_val(pmd) |= _SEGMENT_ENTRY_YOUNG | _SEGMENT_ENTRY_DIRTY;
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}
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return __pmd_to_pte(pmd);
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}
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pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
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unsigned long addr, pte_t *ptep)
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{
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pmd_t *pmdp = (pmd_t *) ptep;
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pte_t pte = huge_ptep_get(ptep);
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pmdp_flush_direct(mm, addr, pmdp);
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pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY;
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return pte;
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}
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int arch_prepare_hugepage(struct page *page)
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{
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unsigned long addr = page_to_phys(page);
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pte_t pte;
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pte_t *ptep;
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int i;
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if (MACHINE_HAS_HPAGE)
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return 0;
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ptep = (pte_t *) pte_alloc_one(&init_mm, addr);
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if (!ptep)
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return -ENOMEM;
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pte_val(pte) = addr;
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for (i = 0; i < PTRS_PER_PTE; i++) {
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set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte);
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pte_val(pte) += PAGE_SIZE;
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}
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page[1].index = (unsigned long) ptep;
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return 0;
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}
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void arch_release_hugepage(struct page *page)
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{
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pte_t *ptep;
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if (MACHINE_HAS_HPAGE)
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return;
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ptep = (pte_t *) page[1].index;
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if (!ptep)
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return;
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clear_table((unsigned long *) ptep, _PAGE_INVALID,
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PTRS_PER_PTE * sizeof(pte_t));
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page_table_free(&init_mm, (unsigned long *) ptep);
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page[1].index = 0;
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}
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pte_t *huge_pte_alloc(struct mm_struct *mm,
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unsigned long addr, unsigned long sz)
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{
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pgd_t *pgdp;
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pud_t *pudp;
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pmd_t *pmdp = NULL;
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pgdp = pgd_offset(mm, addr);
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pudp = pud_alloc(mm, pgdp, addr);
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if (pudp)
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pmdp = pmd_alloc(mm, pudp, addr);
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return (pte_t *) pmdp;
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}
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pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgdp;
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pud_t *pudp;
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pmd_t *pmdp = NULL;
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pgdp = pgd_offset(mm, addr);
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if (pgd_present(*pgdp)) {
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pudp = pud_offset(pgdp, addr);
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if (pud_present(*pudp))
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pmdp = pmd_offset(pudp, addr);
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}
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return (pte_t *) pmdp;
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}
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int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
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{
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return 0;
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}
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struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
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int write)
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{
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return ERR_PTR(-EINVAL);
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}
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int pmd_huge(pmd_t pmd)
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{
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if (!MACHINE_HAS_HPAGE)
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return 0;
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return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE);
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}
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int pud_huge(pud_t pud)
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{
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return 0;
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}
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struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
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pmd_t *pmdp, int write)
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{
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struct page *page;
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if (!MACHINE_HAS_HPAGE)
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return NULL;
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page = pmd_page(*pmdp);
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if (page)
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page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
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return page;
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}
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