148 lines
3.3 KiB
C
148 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Helper routines for building identity mapping page tables. This is
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* included by both the compressed kernel and the regular kernel.
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*/
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static void ident_pmd_init(struct x86_mapping_info *info, pmd_t *pmd_page,
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unsigned long addr, unsigned long end)
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{
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addr &= PMD_MASK;
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for (; addr < end; addr += PMD_SIZE) {
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pmd_t *pmd = pmd_page + pmd_index(addr);
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if (pmd_present(*pmd))
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continue;
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set_pmd(pmd, __pmd((addr - info->offset) | info->page_flag));
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}
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}
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static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
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unsigned long addr, unsigned long end)
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{
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unsigned long next;
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for (; addr < end; addr = next) {
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pud_t *pud = pud_page + pud_index(addr);
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pmd_t *pmd;
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next = (addr & PUD_MASK) + PUD_SIZE;
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if (next > end)
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next = end;
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if (info->direct_gbpages) {
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pud_t pudval;
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if (pud_present(*pud))
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continue;
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addr &= PUD_MASK;
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pudval = __pud((addr - info->offset) | info->page_flag);
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set_pud(pud, pudval);
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continue;
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}
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if (pud_present(*pud)) {
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pmd = pmd_offset(pud, 0);
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ident_pmd_init(info, pmd, addr, next);
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continue;
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}
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pmd = (pmd_t *)info->alloc_pgt_page(info->context);
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if (!pmd)
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return -ENOMEM;
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ident_pmd_init(info, pmd, addr, next);
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set_pud(pud, __pud(__pa(pmd) | info->kernpg_flag));
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}
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return 0;
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}
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static int ident_p4d_init(struct x86_mapping_info *info, p4d_t *p4d_page,
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unsigned long addr, unsigned long end)
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{
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unsigned long next;
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int result;
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for (; addr < end; addr = next) {
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p4d_t *p4d = p4d_page + p4d_index(addr);
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pud_t *pud;
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next = (addr & P4D_MASK) + P4D_SIZE;
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if (next > end)
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next = end;
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if (p4d_present(*p4d)) {
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pud = pud_offset(p4d, 0);
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result = ident_pud_init(info, pud, addr, next);
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if (result)
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return result;
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continue;
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}
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pud = (pud_t *)info->alloc_pgt_page(info->context);
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if (!pud)
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return -ENOMEM;
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result = ident_pud_init(info, pud, addr, next);
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if (result)
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return result;
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set_p4d(p4d, __p4d(__pa(pud) | info->kernpg_flag));
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}
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return 0;
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}
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int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
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unsigned long pstart, unsigned long pend)
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{
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unsigned long addr = pstart + info->offset;
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unsigned long end = pend + info->offset;
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unsigned long next;
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int result;
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/* Set the default pagetable flags if not supplied */
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if (!info->kernpg_flag)
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info->kernpg_flag = _KERNPG_TABLE;
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/* Filter out unsupported __PAGE_KERNEL_* bits: */
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info->kernpg_flag &= __default_kernel_pte_mask;
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for (; addr < end; addr = next) {
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pgd_t *pgd = pgd_page + pgd_index(addr);
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p4d_t *p4d;
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next = (addr & PGDIR_MASK) + PGDIR_SIZE;
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if (next > end)
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next = end;
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if (pgd_present(*pgd)) {
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p4d = p4d_offset(pgd, 0);
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result = ident_p4d_init(info, p4d, addr, next);
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if (result)
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return result;
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continue;
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}
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p4d = (p4d_t *)info->alloc_pgt_page(info->context);
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if (!p4d)
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return -ENOMEM;
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result = ident_p4d_init(info, p4d, addr, next);
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if (result)
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return result;
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if (pgtable_l5_enabled()) {
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set_pgd(pgd, __pgd(__pa(p4d) | info->kernpg_flag));
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} else {
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/*
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* With p4d folded, pgd is equal to p4d.
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* The pgd entry has to point to the pud page table in this case.
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*/
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pud_t *pud = pud_offset(p4d, 0);
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set_pgd(pgd, __pgd(__pa(pud) | info->kernpg_flag));
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}
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}
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return 0;
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}
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