[S390] Improve address space mode selection.

Introduce user_mode to replace the two variables switch_amode and
s390_noexec. There are three valid combinations of the old values:
  1) switch_amode == 0 && s390_noexec == 0
  2) switch_amode == 1 && s390_noexec == 0
  3) switch_amode == 1 && s390_noexec == 1
They get replaced by
  1) user_mode == HOME_SPACE_MODE
  2) user_mode == PRIMARY_SPACE_MODE
  3) user_mode == SECONDARY_SPACE_MODE
The new kernel parameter user_mode=[primary,secondary,home] lets
you choose the address space mode the user space processes should
use. In addition the CONFIG_S390_SWITCH_AMODE config option
is removed.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
index ddad5903341c..68940d0bad91 100644
--- a/arch/s390/include/asm/pgalloc.h
+++ b/arch/s390/include/asm/pgalloc.h
@@ -143,7 +143,8 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
         spin_lock_init(&mm->context.list_lock);
         INIT_LIST_HEAD(&mm->context.crst_list);
         INIT_LIST_HEAD(&mm->context.pgtable_list);
-        return (pgd_t *) crst_table_alloc(mm, s390_noexec);
+        return (pgd_t *)
+                crst_table_alloc(mm, user_mode == SECONDARY_SPACE_MODE);
 }
 #define pgd_free(mm, pgd) crst_table_free(mm, (unsigned long *) pgd)