Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fixes from Martin Schwidefsky:
 "Three more bug fixes for v4.13.

  The two memory management related fixes are quite new, they fix kernel
  crashes that can be triggered by user space.

  The third commit fixes a bug in the vfio ccw translation code"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/mm: fix BUG_ON in crst_table_upgrade
  s390/mm: fork vs. 5 level page tabel
  vfio: ccw: fix bad ptr math for TIC cda translation

3 files changed, 10 insertions, 3 deletions

diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index 4541ac44b35f..24bc41622a98 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -44,6 +44,11 @@ static inline int init_new_context(struct task_struct *tsk,
                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
                 break;
+        case -PAGE_SIZE:
+                /* forked 5-level task, set new asce with new_mm->pgd */
+                mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+                        _ASCE_USER_BITS | _ASCE_TYPE_REGION1;
+                break;
         case 1UL << 53:
                 /* forked 4-level task, set new asce with new mm->pgd */
                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 2e10d2b8ad35..5bea139517a2 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -119,7 +119,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
                 return addr;
 
 check_asce_limit:
-        if (addr + len > current->mm->context.asce_limit) {
+        if (addr + len > current->mm->context.asce_limit &&
+            addr + len <= TASK_SIZE) {
                 rc = crst_table_upgrade(mm, addr + len);
                 if (rc)
                         return (unsigned long) rc;
@@ -183,7 +184,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
         }
 
 check_asce_limit:
-        if (addr + len > current->mm->context.asce_limit) {
+        if (addr + len > current->mm->context.asce_limit &&
+            addr + len <= TASK_SIZE) {
                 rc = crst_table_upgrade(mm, addr + len);
                 if (rc)
                         return (unsigned long) rc;
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index ba6ac83a6c25..5ccfdc80d0ec 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -481,7 +481,7 @@ static int ccwchain_fetch_tic(struct ccwchain *chain,
                 ccw_tail = ccw_head + (iter->ch_len - 1) * sizeof(struct ccw1);
 
                 if ((ccw_head <= ccw->cda) && (ccw->cda <= ccw_tail)) {
-                        ccw->cda = (__u32) (addr_t) (iter->ch_ccw +
+                        ccw->cda = (__u32) (addr_t) (((char *)iter->ch_ccw) +
                                                      (ccw->cda - ccw_head));
                         return 0;
                 }