/*
* IBM System z Huge TLB Page Support for Kernel.
*
* Copyright 2007 IBM Corp.
* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
*/
#include <linux/mm.h>
#include <linux/hugetlb.h>
void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *pteptr, pte_t pteval)
{
pmd_t *pmdp = (pmd_t *) pteptr;
pte_t shadow_pteval = pteval;
unsigned long mask;
if (!MACHINE_HAS_HPAGE) {
pteptr = (pte_t *) pte_page(pteval)[1].index;
mask = pte_val(pteval) &
(_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) | mask;
if (mm->context.noexec) {
pteptr += PTRS_PER_PTE;
pte_val(shadow_pteval) =
(_SEGMENT_ENTRY + __pa(pteptr)) | mask;
}
}
pmd_val(*pmdp) = pte_val(pteval);
if (mm->context.noexec) {
pmdp = get_shadow_table(pmdp);
pmd_val(*pmdp) = pte_val(shadow_pteval);
}
}
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, address);
if (!ptep)
return -ENOMEM;
pte = mk_pte(page, PAGE_RW);
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;
pte_free(&init_mm, ptep);
page[1].index = 0;
}
pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
{
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);
}
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;
}
