powerpc/mm: Add addr_limit to mm_context and use it to derive max slice index

In the followup patch, we will increase the slice array size to handle
512TB range, but will limit the max addr to 128TB. Avoid doing
unnecessary computation and avoid doing slice mask related operation
above address limit.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index e2cf745a4b94..a2c7a6456ee6 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -253,9 +253,10 @@ void copy_mm_to_paca(struct mm_struct *mm)
 
         get_paca()->mm_ctx_id = context->id;
 #ifdef CONFIG_PPC_MM_SLICES
+        VM_BUG_ON(!mm->context.addr_limit);
         get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
         memcpy(&get_paca()->mm_ctx_high_slices_psize,
-               &context->high_slices_psize, SLICE_ARRAY_SIZE);
+               &context->high_slices_psize, TASK_SLICE_ARRAY_SZ(mm));
 #else /* CONFIG_PPC_MM_SLICES */
         get_paca()->mm_ctx_user_psize = context->user_psize;
         get_paca()->mm_ctx_sllp = context->sllp;