1 files changed, 22 insertions, 9 deletions

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 3cb71fc94995..5c2558cc6977 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -300,7 +300,7 @@ early_param("vmalloc", parse_vmalloc);
 
 void *restart_stack __section(.data);
 
-static void __init setup_lowcore(void)
+static void __init setup_lowcore_dat_off(void)
 {
 	struct lowcore *lc;
 
@@ -311,19 +311,16 @@ static void __init setup_lowcore(void)
 	lc = memblock_virt_alloc_low(sizeof(*lc), sizeof(*lc));
 	lc->restart_psw.mask = PSW_KERNEL_BITS;
 	lc->restart_psw.addr = (unsigned long) restart_int_handler;
-	lc->external_new_psw.mask = PSW_KERNEL_BITS |
-		PSW_MASK_DAT | PSW_MASK_MCHECK;
+	lc->external_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK;
 	lc->external_new_psw.addr = (unsigned long) ext_int_handler;
 	lc->svc_new_psw.mask = PSW_KERNEL_BITS |
-		PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
+		PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 	lc->svc_new_psw.addr = (unsigned long) system_call;
-	lc->program_new_psw.mask = PSW_KERNEL_BITS |
-		PSW_MASK_DAT | PSW_MASK_MCHECK;
+	lc->program_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK;
 	lc->program_new_psw.addr = (unsigned long) pgm_check_handler;
 	lc->mcck_new_psw.mask = PSW_KERNEL_BITS;
 	lc->mcck_new_psw.addr = (unsigned long) mcck_int_handler;
-	lc->io_new_psw.mask = PSW_KERNEL_BITS |
-		PSW_MASK_DAT | PSW_MASK_MCHECK;
+	lc->io_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK;
 	lc->io_new_psw.addr = (unsigned long) io_int_handler;
 	lc->clock_comparator = clock_comparator_max;
 	lc->kernel_stack = ((unsigned long) &init_thread_union)
@@ -391,6 +388,16 @@ static void __init setup_lowcore(void)
 	lowcore_ptr[0] = lc;
 }
 
+static void __init setup_lowcore_dat_on(void)
+{
+	__ctl_clear_bit(0, 28);
+	S390_lowcore.external_new_psw.mask |= PSW_MASK_DAT;
+	S390_lowcore.svc_new_psw.mask |= PSW_MASK_DAT;
+	S390_lowcore.program_new_psw.mask |= PSW_MASK_DAT;
+	S390_lowcore.io_new_psw.mask |= PSW_MASK_DAT;
+	__ctl_set_bit(0, 28);
+}
+
 static struct resource code_resource = {
 	.name  = "Kernel code",
 	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
@@ -948,7 +955,7 @@ void __init setup_arch(char **cmdline_p)
 #endif
 
 	setup_resources();
-	setup_lowcore();
+	setup_lowcore_dat_off();
 	smp_fill_possible_mask();
 	cpu_detect_mhz_feature();
         cpu_init();
@@ -961,6 +968,12 @@ void __init setup_arch(char **cmdline_p)
 	 */
         paging_init();
 
+	/*
+	 * After paging_init created the kernel page table, the new PSWs
+	 * in lowcore can now run with DAT enabled.
+	 */
+	setup_lowcore_dat_on();
+
         /* Setup default console */
 	conmode_default();
 	set_preferred_console();