From: Arvind Sankar nivedita@alum.mit.edu
[ Upstream commit 1fcd009102ee02e217f2e7635ab65517d785da8e ]
Commit
ea3b5e60ce80 ("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: ea3b5e60ce80 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/mm/ident_map.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/ident_map.c b/arch/x86/mm/ident_map.c index fe7a12599d8e..968d7005f4a7 100644 --- a/arch/x86/mm/ident_map.c +++ b/arch/x86/mm/ident_map.c @@ -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 next; + int result;
for (; addr < end; addr = next) { 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)) { 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; } pud = (pud_t *)info->alloc_pgt_page(info->context); if (!pud) 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)); }