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authorMichael Holzheu <holzheu@linux.vnet.ibm.com>2012-05-21 11:30:30 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2012-05-23 17:06:51 +0200
commitfa7c0043425624ed65b94a6fabe750c7b0af8719 (patch)
tree8e21c28d65b56a0bd22af1b9a196083233341b3c
parenta9fbf1a53836d4105f95df947ac00e22311dff33 (diff)
downloadlinux-linaro-stable-fa7c0043425624ed65b94a6fabe750c7b0af8719.tar.gz
s390/kdump: Use real mode for PSW restart and kexec
Currently the PSW restart handler and kexec are executed in real mode with DAT=off. For kexec/kdump the function setup_regs() is called that uses the per-cpu variable "crash_notes". Because there are situations when the per-cpu implementation uses vmalloc memory, calling setup_regs() in real mode can cause a program check interrupt. To fix that problem this patch changes the following: * Ensure that diag308_reset() does not change PSW bits to real mode * Enable DAT in __do_restart() after we switched to an online CPU * Enable DAT in __machine_kexec() after we switched to the IPL CPU * Call setup_regs() before we switch to real mode and call purgatory Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/kernel/base.S12
-rw-r--r--arch/s390/kernel/ipl.c1
-rw-r--r--arch/s390/kernel/machine_kexec.c3
3 files changed, 15 insertions, 1 deletions
diff --git a/arch/s390/kernel/base.S b/arch/s390/kernel/base.S
index 3aa4d00aaf50..c880ff72db44 100644
--- a/arch/s390/kernel/base.S
+++ b/arch/s390/kernel/base.S
@@ -88,6 +88,9 @@ ENTRY(diag308_reset)
stctg %c0,%c15,0(%r4)
larl %r4,.Lfpctl # Floating point control register
stfpc 0(%r4)
+ larl %r4,.Lcontinue_psw # Save PSW flags
+ epsw %r2,%r3
+ stm %r2,%r3,0(%r4)
larl %r4,.Lrestart_psw # Setup restart PSW at absolute 0
lghi %r3,0
lg %r4,0(%r4) # Save PSW
@@ -103,11 +106,20 @@ ENTRY(diag308_reset)
lctlg %c0,%c15,0(%r4)
larl %r4,.Lfpctl # Restore floating point ctl register
lfpc 0(%r4)
+ larl %r4,.Lcontinue_psw # Restore PSW flags
+ lpswe 0(%r4)
+.Lcontinue:
br %r14
.align 16
.Lrestart_psw:
.long 0x00080000,0x80000000 + .Lrestart_part2
+ .section .data..nosave,"aw",@progbits
+.align 8
+.Lcontinue_psw:
+ .quad 0,.Lcontinue
+ .previous
+
.section .bss
.align 8
.Lctlregs:
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 8342e65a140d..dcfdcb3ea163 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1750,6 +1750,7 @@ static struct kobj_attribute on_restart_attr =
static void __do_restart(void *ignore)
{
+ __arch_local_irq_stosm(0x04); /* enable DAT */
smp_send_stop();
#ifdef CONFIG_CRASH_DUMP
crash_kexec(NULL);
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index 03d2027d656a..cdacf8f91b2d 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -80,8 +80,8 @@ static void __do_machine_kdump(void *image)
#ifdef CONFIG_CRASH_DUMP
int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
- __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
setup_regs();
+ __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
start_kdump(1);
#endif
}
@@ -214,6 +214,7 @@ static void __machine_kexec(void *data)
{
struct kimage *image = data;
+ __arch_local_irq_stosm(0x04); /* enable DAT */
pfault_fini();
tracing_off();
debug_locks_off();