powerpc/mm/radix: Add checks in slice code to catch radix usage

Radix doesn't need slice support. Catch incorrect usage of slice code
when radix is enabled.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/slice.c

@@ -395,6 +395,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 
 	/* Sanity checks */
 	BUG_ON(mm->task_size == 0);
+	VM_BUG_ON(radix_enabled());
 
 	slice_dbg("slice_get_unmapped_area(mm=%p, psize=%d...\n", mm, psize);
 	slice_dbg(" addr=%lx, len=%lx, flags=%lx, topdown=%d\n",
@@ -568,6 +569,16 @@ unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
 	unsigned char *hpsizes;
 	int index, mask_index;
 
+	/*
+	 * Radix doesn't use slice, but can get enabled along with MMU_SLICE
+	 */
+	if (radix_enabled()) {
+#ifdef CONFIG_PPC_64K_PAGES
+		return MMU_PAGE_64K;
+#else
+		return MMU_PAGE_4K;
+#endif
+	}
 	if (addr < SLICE_LOW_TOP) {
 		u64 lpsizes;
 		lpsizes = mm->context.low_slices_psize;
@@ -605,6 +616,7 @@ void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
 
 	slice_dbg("slice_set_user_psize(mm=%p, psize=%d)\n", mm, psize);
 
+	VM_BUG_ON(radix_enabled());
 	spin_lock_irqsave(&slice_convert_lock, flags);
 
 	old_psize = mm->context.user_psize;
@@ -649,6 +661,7 @@ void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
 {
 	struct slice_mask mask = slice_range_to_mask(start, len);
 
+	VM_BUG_ON(radix_enabled());
 	slice_convert(mm, mask, psize);
 }
 
@@ -678,6 +691,9 @@ int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
 	struct slice_mask mask, available;
 	unsigned int psize = mm->context.user_psize;
 
+	if (radix_enabled())
+		return 0;
+
 	mask = slice_range_to_mask(addr, len);
 	available = slice_mask_for_size(mm, psize);
 #ifdef CONFIG_PPC_64K_PAGES