[S390] s390: use change recording override for kernel mapping

We dont need the dirty bit if a write access is done via the kernel
mapping. In that case SetPageDirty and friends are used anyway, no
need to do that a second time. We can use the change-recording
overide function for the kernel mapping, if available.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 5f91a38d7592..300ab012b0fd 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -70,8 +70,12 @@ static pte_t __ref *vmem_pte_alloc(void)
 		pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));
 	if (!pte)
 		return NULL;
-	clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
-		    PTRS_PER_PTE * sizeof(pte_t));
+	if (MACHINE_HAS_HPAGE)
+		clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY | _PAGE_CO,
+			    PTRS_PER_PTE * sizeof(pte_t));
+	else
+		clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
+			    PTRS_PER_PTE * sizeof(pte_t));
 	return pte;
 }
 
@@ -112,7 +116,8 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
 		if (MACHINE_HAS_HPAGE && !(address & ~HPAGE_MASK) &&
 		    (address + HPAGE_SIZE <= start + size) &&
 		    (address >= HPAGE_SIZE)) {
-			pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
+			pte_val(pte) |= _SEGMENT_ENTRY_LARGE |
+					_SEGMENT_ENTRY_CO;
 			pmd_val(*pm_dir) = pte_val(pte);
 			address += HPAGE_SIZE - PAGE_SIZE;
 			continue;