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x86/mm/ident_map: Check for errors from ident_pud_init() 

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  ea3b5e60ce ("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
This commit is contained in:
Arvind Sankar 2020-10-27 19:06:48 -04:00 committed by Borislav Petkov
parent 3650b228f8
commit 1fcd009102
1 changed files with 10 additions and 2 deletions
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12
arch/x86/mm/ident_map.c
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@ -62,6 +62,7 @@ static int ident_p4d_init(struct x86_mapping_info *info, p4d_t *p4d_page,
unsigned long addr, unsigned long end) unsigned long addr, unsigned long end)
{ {
unsigned long next; unsigned long next;
int result;
for (; addr < end; addr = next) { for (; addr < end; addr = next) {
p4d_t *p4d = p4d_page + p4d_index(addr); p4d_t *p4d = p4d_page + p4d_index(addr);
@ -73,13 +74,20 @@ static int ident_p4d_init(struct x86_mapping_info *info, p4d_t *p4d_page,
if (p4d_present(*p4d)) { if (p4d_present(*p4d)) {
pud = pud_offset(p4d, 0); pud = pud_offset(p4d, 0);
ident_pud_init(info, pud, addr, next); result = ident_pud_init(info, pud, addr, next);
if (result)
return result;
continue; continue;
} }
pud = (pud_t *)info->alloc_pgt_page(info->context); pud = (pud_t *)info->alloc_pgt_page(info->context);
if (!pud) if (!pud)
return -ENOMEM; return -ENOMEM;
ident_pud_init(info, pud, addr, next);
result = ident_pud_init(info, pud, addr, next);
if (result)
return result;
set_p4d(p4d, __p4d(__pa(pud) | info->kernpg_flag)); set_p4d(p4d, __p4d(__pa(pud) | info->kernpg_flag));
} }