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, 3 insertions, 3 deletions

diff --git a/arch/tile/kernel/setup.c b/arch/tile/kernel/setup.c
index 10217844052a..b79c312ca3cb 100644
--- a/arch/tile/kernel/setup.c
+++ b/arch/tile/kernel/setup.c
@@ -1600,7 +1600,7 @@ void __init setup_per_cpu_areas(void)
 
                         /* Update the vmalloc mapping and page home. */
                         unsigned long addr = (unsigned long)ptr + i;
-                        pte_t *ptep = virt_to_pte(NULL, addr);
+                        pte_t *ptep = virt_to_kpte(addr);
                         pte_t pte = *ptep;
                         BUG_ON(pfn != pte_pfn(pte));
                         pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_TILE_L3);
@@ -1609,12 +1609,12 @@ void __init setup_per_cpu_areas(void)
 
                         /* Update the lowmem mapping for consistency. */
                         lowmem_va = (unsigned long)pfn_to_kaddr(pfn);
-                        ptep = virt_to_pte(NULL, lowmem_va);
+                        ptep = virt_to_kpte(lowmem_va);
                         if (pte_huge(*ptep)) {
                                 printk(KERN_DEBUG "early shatter of huge page"
                                        " at %#lx\n", lowmem_va);
                                 shatter_pmd((pmd_t *)ptep);
-                                ptep = virt_to_pte(NULL, lowmem_va);
+                                ptep = virt_to_kpte(lowmem_va);
                                 BUG_ON(pte_huge(*ptep));
                         }
                         BUG_ON(pfn != pte_pfn(*ptep));