The patch titled
Subject: mm: debug_vm_pgtable: Don't use __P000 directly
has been added to the -mm tree. Its filename is
mm-debug_vm_pgtable-dont-use-__p000-directly.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-dont-use-__p000-directly.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-dont-use-__p000-directly.patch
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------------------------------------------------------
From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Subject: mm: debug_vm_pgtable: Don't use __P000 directly
The __Pxxx/__Sxxx macros are only for init protection_map[]. All usage of
them in linux should come from protection_map array.
Because a lot of architectures would re-initilize protection_map[] array,
eg: x86-mem_encrypt, m68k-motorola, mips, arm, sparc.
Using __P000 maybe won't cause bug because hw would deny access with
PROT_NONE permission, but it's not rigorous.
Link: https://lkml.kernel.org/r/20210921201815.284412-1-guoren@xxxxxxxxxx
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Cc: Gavin Shan <gshan@xxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/debug_vm_pgtable.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-dont-use-__p000-directly
+++ a/mm/debug_vm_pgtable.c
@@ -1104,13 +1104,13 @@ static int __init init_args(struct pgtab
/*
* Initialize the debugging data.
*
- * __P000 (or even __S000) will help create page table entries with
+ * __P000 (protection_map[0]) will help create page table entries with
* PROT_NONE permission as required for pxx_protnone_tests().
*/
memset(args, 0, sizeof(*args));
args->vaddr = get_random_vaddr();
args->page_prot = vm_get_page_prot(VMFLAGS);
- args->page_prot_none = __P000;
+ args->page_prot_none = protection_map[0];
args->is_contiguous_page = false;
args->pud_pfn = ULONG_MAX;
args->pmd_pfn = ULONG_MAX;
_
Patches currently in -mm which might be from guoren@xxxxxxxxxxxxxxxxx are
mm-debug_vm_pgtable-dont-use-__p000-directly.patch
