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kernel/linux-imx6_3.14.28/arch/s390/mm/hugetlbpage.c 5.67 KB
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  /*
   *  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;
  }