[PATCH] arm64/mm: Create level specific section mappings in map_range()

[Anshuman Khandual]

Currently PMD section mapping mask i.e PMD_TYPE_SECT is used while creating
section mapping at all page table levels except the last level. This works
fine as the section mapping masks are exactly the same (0x1UL) for all page
table levels.

This will change in the future with D128 page tables that have unique skip
level values (SKL) required for creating section mapping at different page
table levels. Hence use page table level specific section mapping macros
instead of the common PMD_TYPE_SECT.

Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Ryan Roberts <ryan.roberts at arm.com>
Cc: Ard Biesheuvel <ardb at kernel.org>
Cc: linux-kernel at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
---
This patch applies on 6.14-rc5

PGD_TYPE_SECT for level -1 section map handling has been added for 4K
base pages with 52 bit VA configuration that has 5 page table levels.
In such cases (CONFIG_PGTABLE_LEVELS = 5) early_map_kernel() can call
map_range() eventually with -1 (i.e 4 - CONFIG_PGTABLE_LEVELS) as the
root_level.

 arch/arm64/include/asm/pgtable-hwdef.h |  1 +
 arch/arm64/kernel/pi/map_range.c       | 23 +++++++++++++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index a9136cc551cc..fd0a82e8878c 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -99,6 +99,7 @@
 #define PGD_TYPE_TABLE		(_AT(pgdval_t, 3) << 0)
 #define PGD_TABLE_BIT		(_AT(pgdval_t, 1) << 1)
 #define PGD_TYPE_MASK		(_AT(pgdval_t, 3) << 0)
+#define PGD_TYPE_SECT		(_AT(pgdval_t, 1) << 0)
 #define PGD_TABLE_AF		(_AT(pgdval_t, 1) << 10)	/* Ignored if no FEAT_HAFT */
 #define PGD_TABLE_PXN		(_AT(pgdval_t, 1) << 59)
 #define PGD_TABLE_UXN		(_AT(pgdval_t, 1) << 60)
diff --git a/arch/arm64/kernel/pi/map_range.c b/arch/arm64/kernel/pi/map_range.c
index 2b69e3beeef8..9ea869f5745f 100644
--- a/arch/arm64/kernel/pi/map_range.c
+++ b/arch/arm64/kernel/pi/map_range.c
@@ -44,8 +44,27 @@ void __init map_range(u64 *pte, u64 start, u64 end, u64 pa, pgprot_t prot,
 	 * Set the right block/page bits for this level unless we are
 	 * clearing the mapping
 	 */
-	if (protval)
-		protval |= (level < 3) ? PMD_TYPE_SECT : PTE_TYPE_PAGE;
+	if (protval) {
+		switch (level) {
+		case 3:
+			protval |= PTE_TYPE_PAGE;
+			break;
+		case 2:
+			protval |= PMD_TYPE_SECT;
+			break;
+		case 1:
+			protval |= PUD_TYPE_SECT;
+			break;
+		case 0:
+			protval |= P4D_TYPE_SECT;
+			break;
+		case -1:
+			protval |= PGD_TYPE_SECT;
+			break;
+		default:
+			break;
+		}
+	}
 
 	while (start < end) {
 		u64 next = min((start | lmask) + 1, PAGE_ALIGN(end));
-- 
2.30.2