riscv: Add support pte_protnone and pmd_protnone if CONFIG_NUMA_BALANCING

These two functions are used to distinguish between PROT_NONENUMA
protections and hinting fault protections.
Signed-off-by: NGreentime Hu <greentime.hu@sifive.com>
Reviewed-by: NAnup Patel <anup@brainfault.org>
Reviewed-by: NPalmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/include/asm/pgtable.h

@@ -187,6 +187,11 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 	return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
 }
 
+static inline pte_t pmd_pte(pmd_t pmd)
+{
+	return __pte(pmd_val(pmd));
+}
+
 /* Yields the page frame number (PFN) of a page table entry */
 static inline unsigned long pte_pfn(pte_t pte)
 {
@@ -290,6 +295,21 @@ static inline pte_t pte_mkhuge(pte_t pte)
 	return pte;
 }
 
+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * See the comment in include/asm-generic/pgtable.h
+ */
+static inline int pte_protnone(pte_t pte)
+{
+	return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE)) == _PAGE_PROT_NONE;
+}
+
+static inline int pmd_protnone(pmd_t pmd)
+{
+	return pte_protnone(pmd_pte(pmd));
+}
+#endif
+
 /* Modify page protection bits */
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {