arm64: mm: Add definitions to support 5 levels of paging

Add the required types and descriptor accessors to support 5 levels of
paging in the common code. This is one of the prerequisites for
supporting 52-bit virtual addressing with 4k pages.

Note that this does not cover the code that handles kernel mappings or
the fixmap.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-76-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 237224484d0f..cae8c648f462 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -60,6 +60,47 @@ static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot)
 }
 #endif	/* CONFIG_PGTABLE_LEVELS > 3 */
 
+#if CONFIG_PGTABLE_LEVELS > 4
+
+static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t p4dp, pgdval_t prot)
+{
+	if (pgtable_l5_enabled())
+		set_pgd(pgdp, __pgd(__phys_to_pgd_val(p4dp) | prot));
+}
+
+static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgdp, p4d_t *p4dp)
+{
+	pgdval_t pgdval = PGD_TYPE_TABLE;
+
+	pgdval |= (mm == &init_mm) ? PGD_TABLE_UXN : PGD_TABLE_PXN;
+	__pgd_populate(pgdp, __pa(p4dp), pgdval);
+}
+
+static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr)
+{
+	gfp_t gfp = GFP_PGTABLE_USER;
+
+	if (mm == &init_mm)
+		gfp = GFP_PGTABLE_KERNEL;
+	return (p4d_t *)get_zeroed_page(gfp);
+}
+
+static inline void p4d_free(struct mm_struct *mm, p4d_t *p4d)
+{
+	if (!pgtable_l5_enabled())
+		return;
+	BUG_ON((unsigned long)p4d & (PAGE_SIZE-1));
+	free_page((unsigned long)p4d);
+}
+
+#define __p4d_free_tlb(tlb, p4d, addr)  p4d_free((tlb)->mm, p4d)
+#else
+static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t p4dp, pgdval_t prot)
+{
+	BUILD_BUG();
+}
+#endif	/* CONFIG_PGTABLE_LEVELS > 4 */
+
 extern pgd_t *pgd_alloc(struct mm_struct *mm);
 extern void pgd_free(struct mm_struct *mm, pgd_t *pgdp);