commit b11b53342773361f3353b285eb6a3fd6074e7997
author Martin Schwidefsky <schwidefsky@de.ibm.com> Mon Dec 07 12:51:43 2009 +0100
committer Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> Mon Dec 07 12:51:33 2009 +0100
tree b7fda314933b82d39cb8d30c7882ca3044dd0367
parent 61365e132ef987f7719af5d2e434db4465957637

[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>

arch/s390/kernel/vdso.c

diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index adfb32a..5f99e66 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -86,7 +86,8 @@
 	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 @@
 
 	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 @@
 	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)
 {
-	if (switch_amode && vdso_enabled)
+	if (user_mode != HOME_SPACE_MODE && vdso_enabled)
 		on_each_cpu(__vdso_init_cr5, NULL, 1);
 }
 #endif /* CONFIG_64BIT */