[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, 5 insertions, 4 deletions

diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index adfb32aa6d59..5f99e66c51c3 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -86,7 +86,8 @@ static void vdso_init_data(struct vdso_data *vd)
         unsigned int facility_list;
 
         facility_list = stfl();
-        vd->ectg_available = switch_amode && (facility_list & 1);
+        vd->ectg_available =
+                user_mode != HOME_SPACE_MODE && (facility_list & 1);
 }
 
 #ifdef CONFIG_64BIT
@@ -114,7 +115,7 @@ int vdso_alloc_per_cpu(int cpu, struct _lowcore *lowcore)
 
         lowcore->vdso_per_cpu_data = __LC_PASTE;
 
-        if (!switch_amode || !vdso_enabled)
+        if (user_mode == HOME_SPACE_MODE || !vdso_enabled)
                 return 0;
 
         segment_table = __get_free_pages(GFP_KERNEL, SEGMENT_ORDER);
@@ -160,7 +161,7 @@ void vdso_free_per_cpu(int cpu, struct _lowcore *lowcore)
         unsigned long segment_table, page_table, page_frame;
         u32 *psal, *aste;
 
-        if (!switch_amode || !vdso_enabled)
+        if (user_mode == HOME_SPACE_MODE || !vdso_enabled)
                 return;
 
         psal = (u32 *)(addr_t) lowcore->paste[4];
@@ -184,7 +185,7 @@ static void __vdso_init_cr5(void *dummy)
 
 static void vdso_init_cr5(void)
 {
-        if (switch_amode && vdso_enabled)
+        if (user_mode != HOME_SPACE_MODE && vdso_enabled)
                 on_each_cpu(__vdso_init_cr5, NULL, 1);
 }
 #endif /* CONFIG_64BIT */