void huge_ptep_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
unsigned long pfn, dpfn;
pgprot_t hugeprot;
int ncontig, i;
size_t pgsize;
pte_t pte;
if (!pte_cont(READ_ONCE(*ptep))) {
ptep_set_wrprotect(mm, addr, ptep);
return;
}
ncontig = find_num_contig(mm, addr, ptep, &pgsize);
dpfn = pgsize >> PAGE_SHIFT;
pte = get_clear_flush(mm, addr, ptep, pgsize, ncontig);
pte = pte_wrprotect(pte);
hugeprot = pte_pgprot(pte);
pfn = pte_pfn(pte);
for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot));
}
inline int make_page_cow(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
spinlock_t *ptl;
pgd = pgd_offset(mm, addr);
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
goto no_page;
pud = pud_offset(pgd, addr);
if (pud_none(*pud) || unlikely(pud_bad(*pud)))
goto no_page;
pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
goto no_page;
BUG_ON(pmd_trans_huge(*pmd));
pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
if (!pte_present(*pte)) {
spin_unlock(ptl);
goto no_page;
}
ptep_set_wrprotect(mm, addr, pte);
spin_unlock(ptl);
#if !defined(CONFIG_GRAPHENE_BULK_IPC) && LINUX_VERSION_CODE >= KERNEL_VERSION(3, 2, 0)
my_flush_tlb_page(vma, addr);
#else
flush_tlb_page(vma, addr);
#endif
DEBUG("make page COW at %lx\n", addr);
return 0;
no_page:
return -EFAULT;
}
/*
* copy one vm_area from one task to the other. Assumes the page tables
* already present in the new task to be cleared in the whole range
* covered by this vma.
*
* 08Jan98 Merged into one routine from several inline routines to reduce
* variable count and make things faster. -jj
*/
int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
struct vm_area_struct *vma)
{
pgd_t * src_pgd, * dst_pgd;
unsigned long address = vma->vm_start;
unsigned long end = vma->vm_end;
unsigned long cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
src_pgd = pgd_offset(src, address)-1;
dst_pgd = pgd_offset(dst, address)-1;
for (;;) {
pmd_t * src_pmd, * dst_pmd;
src_pgd++; dst_pgd++;
/* copy_pmd_range */
if (pgd_none(*src_pgd))
goto skip_copy_pmd_range;
if (pgd_bad(*src_pgd)) {
pgd_ERROR(*src_pgd);
pgd_clear(src_pgd);
skip_copy_pmd_range: address = (address + PGDIR_SIZE) & PGDIR_MASK;
if (!address || (address >= end))
goto out;
continue;
}
if (pgd_none(*dst_pgd)) {
if (!pmd_alloc(dst_pgd, 0))
goto nomem;
}
src_pmd = pmd_offset(src_pgd, address);
dst_pmd = pmd_offset(dst_pgd, address);
do {
pte_t * src_pte, * dst_pte;
/* copy_pte_range */
if (pmd_none(*src_pmd))
goto skip_copy_pte_range;
if (pmd_bad(*src_pmd)) {
pmd_ERROR(*src_pmd);
pmd_clear(src_pmd);
skip_copy_pte_range: address = (address + PMD_SIZE) & PMD_MASK;
if (address >= end)
goto out;
goto cont_copy_pmd_range;
}
if (pmd_none(*dst_pmd)) {
if (!pte_alloc(dst_pmd, 0))
goto nomem;
}
src_pte = pte_offset(src_pmd, address);
dst_pte = pte_offset(dst_pmd, address);
do {
pte_t pte = *src_pte;
struct page *ptepage;
/* copy_one_pte */
if (pte_none(pte))
goto cont_copy_pte_range_noset;
if (!pte_present(pte)) {
swap_duplicate(pte_to_swp_entry(pte));
goto cont_copy_pte_range;
}
ptepage = pte_page(pte);
if ((!VALID_PAGE(ptepage)) ||
PageReserved(ptepage))
goto cont_copy_pte_range;
/* If it's a COW mapping, write protect it both in the parent and the child */
if (cow) {
ptep_set_wrprotect(src_pte);
pte = *src_pte;
}
/* If it's a shared mapping, mark it clean in the child */
if (vma->vm_flags & VM_SHARED)
pte = pte_mkclean(pte);
pte = pte_mkold(pte);
get_page(ptepage);
cont_copy_pte_range: set_pte(dst_pte, pte);
cont_copy_pte_range_noset: address += PAGE_SIZE;
if (address >= end)
goto out;
src_pte++;
dst_pte++;
} while ((unsigned long)src_pte & PTE_TABLE_MASK);
cont_copy_pmd_range: src_pmd++;
dst_pmd++;
} while ((unsigned long)src_pmd & PMD_TABLE_MASK);
}
out:
return 0;
nomem:
return -ENOMEM;
}