tile: add virt_to_kpte() API and clean up and document behavior
We use virt_to_pte(NULL, va) a lot, which isn't very obvious.
I added virt_to_kpte(va) as a more obvious wrapper function,
that also validates the va as being a kernel adddress.
And, I fixed the semantics of virt_to_pte() so that we handle
the pud and pmd the same way, and we now document the fact that
we handle the final pte level differently.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
index 3004433..2deaddf 100644
--- a/arch/tile/mm/pgtable.c
+++ b/arch/tile/mm/pgtable.c
@@ -325,6 +325,17 @@
#endif
+/*
+ * Return a pointer to the PTE that corresponds to the given
+ * address in the given page table. A NULL page table just uses
+ * the standard kernel page table; the preferred API in this case
+ * is virt_to_kpte().
+ *
+ * The returned pointer can point to a huge page in other levels
+ * of the page table than the bottom, if the huge page is present
+ * in the page table. For bottom-level PTEs, the returned pointer
+ * can point to a PTE that is either present or not.
+ */
pte_t *virt_to_pte(struct mm_struct* mm, unsigned long addr)
{
pgd_t *pgd;
@@ -341,14 +352,21 @@
if (pud_huge_page(*pud))
return (pte_t *)pud;
pmd = pmd_offset(pud, addr);
- if (pmd_huge_page(*pmd))
- return (pte_t *)pmd;
if (!pmd_present(*pmd))
return NULL;
+ if (pmd_huge_page(*pmd))
+ return (pte_t *)pmd;
return pte_offset_kernel(pmd, addr);
}
EXPORT_SYMBOL(virt_to_pte);
+pte_t *virt_to_kpte(unsigned long kaddr)
+{
+ BUG_ON(kaddr < PAGE_OFFSET);
+ return virt_to_pte(NULL, kaddr);
+}
+EXPORT_SYMBOL(virt_to_kpte);
+
pgprot_t set_remote_cache_cpu(pgprot_t prot, int cpu)
{
unsigned int width = smp_width;
