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/*
* Helper routines for building identity mapping page tables. This is
* included by both the compressed kernel and the regular kernel.
*/
static void ident_pmd_init(unsigned long pmd_flag, pmd_t *pmd_page,
unsigned long addr, unsigned long end)
{
addr &= PMD_MASK;
for (; addr < end; addr += PMD_SIZE) {
pmd_t *pmd = pmd_page + pmd_index(addr);
if (!pmd_present(*pmd))
set_pmd(pmd, __pmd(addr | pmd_flag));
}
}
static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
unsigned long addr, unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next) {
pud_t *pud = pud_page + pud_index(addr);
pmd_t *pmd;
next = (addr & PUD_MASK) + PUD_SIZE;
if (next > end)
next = end;
if (pud_present(*pud)) {
pmd = pmd_offset(pud, 0);
ident_pmd_init(info->pmd_flag, pmd, addr, next);
continue;
}
pmd = (pmd_t *)info->alloc_pgt_page(info->context);
if (!pmd)
return -ENOMEM;
ident_pmd_init(info->pmd_flag, pmd, addr, next);
set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
}
return 0;
}
int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
unsigned long addr, unsigned long end)
{
unsigned long next;
int result;
int off = info->kernel_mapping ? pgd_index(__PAGE_OFFSET) : 0;
for (; addr < end; addr = next) {
pgd_t *pgd = pgd_page + pgd_index(addr) + off;
pud_t *pud;
next = (addr & PGDIR_MASK) + PGDIR_SIZE;
if (next > end)
next = end;
if (pgd_present(*pgd)) {
pud = pud_offset(pgd, 0);
result = ident_pud_init(info, pud, addr, next);
if (result)
return result;
continue;
}
pud = (pud_t *)info->alloc_pgt_page(info->context);
if (!pud)
return -ENOMEM;
result = ident_pud_init(info, pud, addr, next);
if (result)
return result;
set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
}
return 0;
}
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