s390/mm: add missing arch_set_page_dat() call to gmap allocations

If the cmma no-dat feature is available all pages that are not used for
dynamic address translation are marked as "no-dat" with the ESSA
instruction. This information is visible to the hypervisor, so that the
hypervisor can optimize purging of guest TLB entries. This also means that
pages which are used for dynamic address translation must not be marked as
"no-dat", since the hypervisor may then incorrectly not purge guest TLB
entries.

Region, segment, and page tables allocated within the gmap code are
incorrectly marked as "no-dat", since an explicit call to
arch_set_page_dat() is missing, which would remove the "no-dat" mark.

In order to fix this add a new gmap_alloc_crst() function which should
be used to allocate region and segment tables, and which also calls
arch_set_page_dat().

Also add the arch_set_page_dat() call to page_table_alloc_pgste().

Cc: <stable@vger.kernel.org>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index a6b71bc71896..a7e4b6e11cc5 100644
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -146,6 +146,7 @@ struct page *page_table_alloc_pgste(struct mm_struct *mm)
 	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
 	if (ptdesc) {
 		table = (u64 *)ptdesc_to_virt(ptdesc);
+		arch_set_page_dat(virt_to_page(table), 0);
 		memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
 		memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
 	}