[PATCH] arm64/mm: Compute PTRS_PER_[PMD|PUD] independently of PTRS_PER_PTE

From: Anshuman Khandual
Date: Fri Apr 08 2022 - 00:09:55 EST


Possible page table entries (or pointers) on non-zero page table levels are
dependent on a single page size i.e PAGE_SIZE and size required for each
individual page table entry i.e 8 bytes. PTRS_PER_[PMD|PUD] as such are not
related to PTRS_PER_PTE in any manner, as being implied currently. So lets
just make this very explicit and compute these macros independently.

Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
This applies on v5.18-rc1

arch/arm64/include/asm/pgtable-hwdef.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index 66671ff05183..dd3d12bce07b 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -49,7 +49,7 @@
#define PMD_SHIFT ARM64_HW_PGTABLE_LEVEL_SHIFT(2)
#define PMD_SIZE (_AC(1, UL) << PMD_SHIFT)
#define PMD_MASK (~(PMD_SIZE-1))
-#define PTRS_PER_PMD PTRS_PER_PTE
+#define PTRS_PER_PMD (1 << (PAGE_SHIFT - 3))
#endif

/*
@@ -59,7 +59,7 @@
#define PUD_SHIFT ARM64_HW_PGTABLE_LEVEL_SHIFT(1)
#define PUD_SIZE (_AC(1, UL) << PUD_SHIFT)
#define PUD_MASK (~(PUD_SIZE-1))
-#define PTRS_PER_PUD PTRS_PER_PTE
+#define PTRS_PER_PUD (1 << (PAGE_SHIFT - 3))
#endif

/*
--
2.20.1