[PATCH V3] mm: debug_vm_pgtable: Don't use __P000 directly

[guoren]

From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

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.

Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>

---
Changes since V3:
 - Add Reviewed-by: Anshuman Khandual
 - Add Cc: Christoph Hellwig

Changes since V2:
 - s/init protection_map[]/protection_map[] init/
 - s/Becasue/Because/
 - Remove unclear part
 - Replace __P000 and __S000 with protection_map[0] and
   protection_map[8]
---
 mm/debug_vm_pgtable.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 1403639302e4..228e3954b90c 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -1104,13 +1104,14 @@ static int __init init_args(struct pgtable_debug_args *args)
 	/*
 	 * 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;
-- 
2.25.1