[patch 030/262] mm: debug_vm_pgtable: don't use __P000 directly

Andrew Morton
2021-11-05T20:36:11Z

From: Guo Ren <guoren@linux.alibaba.com>
Subject: mm: debug_vm_pgtable: don't use __P000 directly

The __Pxxx/__Sxxx macros are only for protection_map[] init. 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 is not rigorous.

Link: https://lkml.kernel.org/r/20210924060821.1138281-1-guoren@kernel.org
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

mm/debug_vm_pgtable.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-dont-use-__p000-directly
+++ a/mm/debug_vm_pgtable.c
@@ -1104,13 +1104,14 @@ static int __init init_args(struct pgtab
/*
* Initialize the debugging data.
*
- * __P000 (or even __S000) will help create page table entries with
- * PROT_NONE permission as required for pxx_protnone_tests().
+ * protection_map[0] (or even protection_map[8]) 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;
_