mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
![Arvind Sankar](/assets/img/avatar_default.png)
Commitea3b5e60ce
("x86/mm/ident_map: Add 5-level paging support") added ident_p4d_init() to support 5-level paging, but this function doesn't check and return errors from ident_pud_init(). For example, the decompressor stub uses this code to create an identity mapping. If it runs out of pages while trying to allocate a PMD pagetable, the error will be currently ignored. Fix this to propagate errors. [ bp: Space out statements for better readability. ] Fixes:ea3b5e60ce
("x86/mm/ident_map: Add 5-level paging support") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Joerg Roedel <jroedel@suse.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Link: https://lkml.kernel.org/r/20201027230648.1885111-1-nivedita@alum.mit.edu
147 lines
3.3 KiB
C
147 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* 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(struct x86_mapping_info *info, 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))
|
|
continue;
|
|
|
|
set_pmd(pmd, __pmd((addr - info->offset) | info->page_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 (info->direct_gbpages) {
|
|
pud_t pudval;
|
|
|
|
if (pud_present(*pud))
|
|
continue;
|
|
|
|
addr &= PUD_MASK;
|
|
pudval = __pud((addr - info->offset) | info->page_flag);
|
|
set_pud(pud, pudval);
|
|
continue;
|
|
}
|
|
|
|
if (pud_present(*pud)) {
|
|
pmd = pmd_offset(pud, 0);
|
|
ident_pmd_init(info, pmd, addr, next);
|
|
continue;
|
|
}
|
|
pmd = (pmd_t *)info->alloc_pgt_page(info->context);
|
|
if (!pmd)
|
|
return -ENOMEM;
|
|
ident_pmd_init(info, pmd, addr, next);
|
|
set_pud(pud, __pud(__pa(pmd) | info->kernpg_flag));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ident_p4d_init(struct x86_mapping_info *info, p4d_t *p4d_page,
|
|
unsigned long addr, unsigned long end)
|
|
{
|
|
unsigned long next;
|
|
int result;
|
|
|
|
for (; addr < end; addr = next) {
|
|
p4d_t *p4d = p4d_page + p4d_index(addr);
|
|
pud_t *pud;
|
|
|
|
next = (addr & P4D_MASK) + P4D_SIZE;
|
|
if (next > end)
|
|
next = end;
|
|
|
|
if (p4d_present(*p4d)) {
|
|
pud = pud_offset(p4d, 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_p4d(p4d, __p4d(__pa(pud) | info->kernpg_flag));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
|
|
unsigned long pstart, unsigned long pend)
|
|
{
|
|
unsigned long addr = pstart + info->offset;
|
|
unsigned long end = pend + info->offset;
|
|
unsigned long next;
|
|
int result;
|
|
|
|
/* Set the default pagetable flags if not supplied */
|
|
if (!info->kernpg_flag)
|
|
info->kernpg_flag = _KERNPG_TABLE;
|
|
|
|
/* Filter out unsupported __PAGE_KERNEL_* bits: */
|
|
info->kernpg_flag &= __default_kernel_pte_mask;
|
|
|
|
for (; addr < end; addr = next) {
|
|
pgd_t *pgd = pgd_page + pgd_index(addr);
|
|
p4d_t *p4d;
|
|
|
|
next = (addr & PGDIR_MASK) + PGDIR_SIZE;
|
|
if (next > end)
|
|
next = end;
|
|
|
|
if (pgd_present(*pgd)) {
|
|
p4d = p4d_offset(pgd, 0);
|
|
result = ident_p4d_init(info, p4d, addr, next);
|
|
if (result)
|
|
return result;
|
|
continue;
|
|
}
|
|
|
|
p4d = (p4d_t *)info->alloc_pgt_page(info->context);
|
|
if (!p4d)
|
|
return -ENOMEM;
|
|
result = ident_p4d_init(info, p4d, addr, next);
|
|
if (result)
|
|
return result;
|
|
if (pgtable_l5_enabled()) {
|
|
set_pgd(pgd, __pgd(__pa(p4d) | info->kernpg_flag));
|
|
} else {
|
|
/*
|
|
* With p4d folded, pgd is equal to p4d.
|
|
* The pgd entry has to point to the pud page table in this case.
|
|
*/
|
|
pud_t *pud = pud_offset(p4d, 0);
|
|
set_pgd(pgd, __pgd(__pa(pud) | info->kernpg_flag));
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|