[RFC V2 01/14] mm: Abstract printing of pxd_val()

[Anshuman Khandual]

Ahead of adding support for D128 pgtables, refactor places that print
PTE values to use the new __PRIpte format specifier and __PRIpte_args()
macro to prepare the argument(s). When using D128 pgtables in future,
we can simply redefine __PRIpte and __PTIpte_args().

Besides there is also an assumption about pxd_val() being always capped
at 'unsigned long long' size but that will not work for D128 pgtables.
Just increase its size to u128 if the compiler supports via a separate
data type pxdval_t which also defaults to existing 'unsigned long long'.

Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: David Hildenbrand <david at kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes at oracle.com>
Cc: Mike Rapoport <rppt at kernel.org>
Cc: linux-mm at kvack.org
Cc: linux-kernel at vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
---
Changes in RFC V2:

- Moved pxdval_t definition inside generic page table header per Mike
- Restored print format in __print_bad_page_map_pgtable() per Usama
- Renamed __PRIpte as __PRIpxx per David

 include/linux/pgtable.h | 11 +++++++++++
 mm/memory.c             | 23 +++++++++++++----------
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index cdd68ed3ae1a..a738048128e7 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -17,6 +17,17 @@
 #include <asm-generic/pgtable_uffd.h>
 #include <linux/page_table_check.h>
 
+#ifdef __SIZEOF_INT128__
+typedef u128 pxdval_t;
+#else
+typedef unsigned long long pxdval_t;
+#endif
+
+#ifndef __PRIpxx
+#define __PRIpxx		"016llx"
+#define __PRIpxx_args(val)	((u64)val)
+#endif
+
 #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
 	defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
 #error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
diff --git a/mm/memory.c b/mm/memory.c
index ea6568571131..7b6ee3b847a0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -521,7 +521,7 @@ static bool is_bad_page_map_ratelimited(void)
 
 static void __print_bad_page_map_pgtable(struct mm_struct *mm, unsigned long addr)
 {
-	unsigned long long pgdv, p4dv, pudv, pmdv;
+	pxdval_t pgdv, p4dv, pudv, pmdv;
 	p4d_t p4d, *p4dp;
 	pud_t pud, *pudp;
 	pmd_t pmd, *pmdp;
@@ -535,7 +535,7 @@ static void __print_bad_page_map_pgtable(struct mm_struct *mm, unsigned long add
 	pgdv = pgd_val(*pgdp);
 
 	if (!pgd_present(*pgdp) || pgd_leaf(*pgdp)) {
-		pr_alert("pgd:%08llx\n", pgdv);
+		pr_alert("pgd:%" __PRIpxx "\n", __PRIpxx_args(pgdv));
 		return;
 	}
 
@@ -544,7 +544,8 @@ static void __print_bad_page_map_pgtable(struct mm_struct *mm, unsigned long add
 	p4dv = p4d_val(p4d);
 
 	if (!p4d_present(p4d) || p4d_leaf(p4d)) {
-		pr_alert("pgd:%08llx p4d:%08llx\n", pgdv, p4dv);
+		pr_alert("pgd:%" __PRIpxx " p4d:%" __PRIpxx "\n",
+			 __PRIpxx_args(pgdv), __PRIpxx_args(p4dv));
 		return;
 	}
 
@@ -553,7 +554,8 @@ static void __print_bad_page_map_pgtable(struct mm_struct *mm, unsigned long add
 	pudv = pud_val(pud);
 
 	if (!pud_present(pud) || pud_leaf(pud)) {
-		pr_alert("pgd:%08llx p4d:%08llx pud:%08llx\n", pgdv, p4dv, pudv);
+		pr_alert("pgd:%" __PRIpxx " p4d:%" __PRIpxx " pud:%" __PRIpxx "\n",
+			 __PRIpxx_args(pgdv), __PRIpxx_args(p4dv), __PRIpxx_args(pudv));
 		return;
 	}
 
@@ -567,8 +569,9 @@ static void __print_bad_page_map_pgtable(struct mm_struct *mm, unsigned long add
 	 * doing another map would be bad. print_bad_page_map() should
 	 * already take care of printing the PTE.
 	 */
-	pr_alert("pgd:%08llx p4d:%08llx pud:%08llx pmd:%08llx\n", pgdv,
-		 p4dv, pudv, pmdv);
+	pr_alert("pgd:%" __PRIpxx " p4d:%" __PRIpxx " pud:%" __PRIpxx " pmd:%" __PRIpxx "\n",
+		 __PRIpxx_args(pgdv), __PRIpxx_args(p4dv),
+		 __PRIpxx_args(pudv), __PRIpxx_args(pmdv));
 }
 
 /*
@@ -584,7 +587,7 @@ static void __print_bad_page_map_pgtable(struct mm_struct *mm, unsigned long add
  * page table lock.
  */
 static void print_bad_page_map(struct vm_area_struct *vma,
-		unsigned long addr, unsigned long long entry, struct page *page,
+		unsigned long addr, pxdval_t entry, struct page *page,
 		enum pgtable_level level)
 {
 	struct address_space *mapping;
@@ -596,8 +599,8 @@ static void print_bad_page_map(struct vm_area_struct *vma,
 	mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
 	index = linear_page_index(vma, addr);
 
-	pr_alert("BUG: Bad page map in process %s  %s:%08llx", current->comm,
-		 pgtable_level_to_str(level), entry);
+	pr_alert("BUG: Bad page map in process %s  %s:%" __PRIpxx, current->comm,
+		 pgtable_level_to_str(level), __PRIpxx_args(entry));
 	__print_bad_page_map_pgtable(vma->vm_mm, addr);
 	if (page)
 		dump_page(page, "bad page map");
@@ -682,7 +685,7 @@ static void print_bad_page_map(struct vm_area_struct *vma,
  */
 static inline struct page *__vm_normal_page(struct vm_area_struct *vma,
 		unsigned long addr, unsigned long pfn, bool special,
-		unsigned long long entry, enum pgtable_level level)
+		pxdval_t entry, enum pgtable_level level)
 {
 	if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) {
 		if (unlikely(special)) {
-- 
2.43.0