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/homecache.c b/arch/tile/mm/homecache.c
index df46a2d..e3ee55b 100644
--- a/arch/tile/mm/homecache.c
+++ b/arch/tile/mm/homecache.c
@@ -200,7 +200,7 @@
#else
va = __fix_to_virt(FIX_HOMECACHE_BEGIN + smp_processor_id());
#endif
- ptep = virt_to_pte(NULL, (unsigned long)va);
+ ptep = virt_to_kpte(va);
pte = pfn_pte(page_to_pfn(page), PAGE_KERNEL);
__set_pte(ptep, pte_set_home(pte, home));
homecache_finv_page_va((void *)va, home);
@@ -385,7 +385,7 @@
return initial_page_home();
} else {
unsigned long kva = (unsigned long)page_address(page);
- return pte_to_home(*virt_to_pte(NULL, kva));
+ return pte_to_home(*virt_to_kpte(kva));
}
}
EXPORT_SYMBOL(page_home);
@@ -404,7 +404,7 @@
NULL, 0);
for (i = 0; i < pages; ++i, kva += PAGE_SIZE) {
- pte_t *ptep = virt_to_pte(NULL, kva);
+ pte_t *ptep = virt_to_kpte(kva);
pte_t pteval = *ptep;
BUG_ON(!pte_present(pteval) || pte_huge(pteval));
__set_pte(ptep, pte_set_home(pteval, home));
diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index c6d2160..c8f58c1 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -951,7 +951,7 @@
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 @@
*/
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
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;
