[RFC PATCH 14/20] arm64: mm: add __{pud,pgd}_populate

[Mark Rutland]

We currently have __pmd_populate for creating a pmd table entry given
the physical address of a pte, but don't have equivalents for the pud or
pgd levels of table.

To enable us to manipulate tables which are mapped outside of the linear
mapping (where we have a PA, but not a linear map VA), it is useful to
have these functions.

This patch adds __{pud,pgd}_populate. As these should not be called when
the kernel uses folded {pmd,pud}s, in these cases they expand to
BUILD_BUG(). So long as the appropriate checks are made on the {pud,pgd}
entry prior to attempting population, these should be optimized out at
compile time.

Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Jeremy Linton <jeremy.linton at arm.com>
Cc: Laura Abbott <labbott at fedoraproject.org>
Cc: Will Deacon <will.deacon at arm.com>
---
 arch/arm64/include/asm/pgalloc.h | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index c150539..ff98585 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -42,11 +42,20 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 	free_page((unsigned long)pmd);
 }
 
-static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
+static inline void __pud_populate(pud_t *pud, phys_addr_t pmd, pudval_t prot)
 {
-	set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE));
+	set_pud(pud, __pud(pmd | prot));
 }
 
+static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
+{
+	__pud_populate(pud, __pa(pmd), PMD_TYPE_TABLE);
+}
+#else
+static inline void __pud_populate(pud_t *pud, phys_addr_t pmd, pudval_t prot)
+{
+	BUILD_BUG();
+}
 #endif	/* CONFIG_PGTABLE_LEVELS > 2 */
 
 #if CONFIG_PGTABLE_LEVELS > 3
@@ -62,11 +71,20 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud)
 	free_page((unsigned long)pud);
 }
 
-static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pud_t *pud)
+static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t pud, pgdval_t prot)
 {
-	set_pgd(pgd, __pgd(__pa(pud) | PUD_TYPE_TABLE));
+	set_pgd(pgdp, __pgd(pud | prot));
 }
 
+static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pud_t *pud)
+{
+	__pgd_populate(pgd, __pa(pud), PUD_TYPE_TABLE);
+}
+#else
+static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t pud, pgdval_t prot)
+{
+	BUILD_BUG();
+}
 #endif	/* CONFIG_PGTABLE_LEVELS > 3 */
 
 extern pgd_t *pgd_alloc(struct mm_struct *mm);
-- 
1.9.1