powerpc/64s/hash: Provide arch_setup_exec() hooks for hash slice setup

This will be used by the SLB code in the next patch, but for now this
sets the slb_addr_limit to the correct size for 32-bit tasks.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/mmu_context_book3s64.c

@@ -84,6 +84,11 @@ static int hash__init_new_context(struct mm_struct *mm)
 	return index;
 }
 
+void hash__setup_new_exec(void)
+{
+	slice_setup_new_exec();
+}
+
 static int radix__init_new_context(struct mm_struct *mm)
 {
 	unsigned long rts_field;

arch/powerpc/mm/slice.c

@@ -757,6 +757,20 @@ void slice_init_new_context_exec(struct mm_struct *mm)
 		bitmap_fill(mask->high_slices, SLICE_NUM_HIGH);
 }
 
+#ifdef CONFIG_PPC_BOOK3S_64
+void slice_setup_new_exec(void)
+{
+	struct mm_struct *mm = current->mm;
+
+	slice_dbg("slice_setup_new_exec(mm=%p)\n", mm);
+
+	if (!is_32bit_task())
+		return;
+
+	mm->context.slb_addr_limit = DEFAULT_MAP_WINDOW;
+}
+#endif
+
 void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
 			   unsigned long len, unsigned int psize)
 {