[POWERPC] Cleanup 32-bit map_page

The 32 bits map_page() function is used internally by the mm code
for early mmu mappings and for ioremap. It should never be called
for an address that already has a valid PTE or hash entry, so we
add a BUG_ON for that and remove the useless flush_HPTE call.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

 arch/powerpc/mm/pgtable_32.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/mm/pgtable_32.c

@@ -266,9 +266,12 @@ int map_page(unsigned long va, phys_addr_t pa, int flags)
 	pg = pte_alloc_kernel(pd, va);
 	if (pg != 0) {
 		err = 0;
-		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
-		if (mem_init_done)
-			flush_HPTE(0, va, pmd_val(*pd));
+		/* The PTE should never be already set nor present in the
+		 * hash table
+		 */
+		BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
+		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
+						     __pgprot(flags)));
 	}
 	return err;
 }