arm64/mm: Convert __pte_to_phys() and __phys_to_pte_val() as functions

When CONFIG_ARM64_PA_BITS_52 is enabled, page table helpers __pte_to_phys()
and __phys_to_pte_val() are functions which return phys_addr_t and pteval_t
respectively as expected. But otherwise without this config being enabled,
they are defined as macros and their return types are implicit.

Until now this has worked out correctly as both pte_t and phys_addr_t data
types have been 64 bits. But with the introduction of 128 bit page tables,
pte_t becomes 128 bits. Hence this ends up with incorrect widths after the
conversions, which leads to compiler warnings.

Fix these warnings by converting __pte_to_phys() and __phys_to_pte_val()
as functions instead where the return types are handled explicitly.

Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://lore.kernel.org/r/20250227022412.2015835-1-anshuman.khandual@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: Anshuman Khandual

arch/arm64/include/asm/pgtable.h

@@ -68,10 +68,6 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 #define pte_ERROR(e)	\
 	pr_err("%s:%d: bad pte %016llx.\n", __FILE__, __LINE__, pte_val(e))
 
-/*
- * Macros to convert between a physical address and its placement in a
- * page table entry, taking care of 52-bit addresses.
- */
 #ifdef CONFIG_ARM64_PA_BITS_52
 static inline phys_addr_t __pte_to_phys(pte_t pte)
 {
@@ -84,8 +80,15 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
 	return (phys | (phys >> PTE_ADDR_HIGH_SHIFT)) & PHYS_TO_PTE_ADDR_MASK;
 }
 #else
-#define __pte_to_phys(pte)	(pte_val(pte) & PTE_ADDR_LOW)
-#define __phys_to_pte_val(phys)	(phys)
+static inline phys_addr_t __pte_to_phys(pte_t pte)
+{
+	return pte_val(pte) & PTE_ADDR_LOW;
+}
+
+static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
+{
+	return phys;
+}
 #endif
 
 #define pte_pfn(pte)		(__pte_to_phys(pte) >> PAGE_SHIFT)