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>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index c6d21601ec4d..c8f58c12866d 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -951,7 +951,7 @@ static void mark_w1data_ro(void)
         BUG_ON((addr & (PAGE_SIZE-1)) != 0);
         for (; addr <= (unsigned long)__w1data_end - 1; addr += PAGE_SIZE) {
                 unsigned long pfn = kaddr_to_pfn((void *)addr);
-                pte_t *ptep = virt_to_pte(NULL, addr);
+                pte_t *ptep = virt_to_kpte(addr);
                 BUG_ON(pte_huge(*ptep));   /* not relevant for kdata_huge */
                 set_pte_at(&init_mm, addr, ptep, pfn_pte(pfn, PAGE_KERNEL_RO));
         }
@@ -997,7 +997,7 @@ static void free_init_pages(char *what, unsigned long begin, unsigned long end)
                  */
                 int pfn = kaddr_to_pfn((void *)addr);
                 struct page *page = pfn_to_page(pfn);
-                pte_t *ptep = virt_to_pte(NULL, addr);
+                pte_t *ptep = virt_to_kpte(addr);
                 if (!initfree) {
                         /*
                          * If debugging page accesses then do not free