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Diffstat (limited to 'arch/s390/kernel/base.S')
-rw-r--r--arch/s390/kernel/base.S21
1 files changed, 17 insertions, 4 deletions
diff --git a/arch/s390/kernel/base.S b/arch/s390/kernel/base.S
index daed3fde42ec..326f717df587 100644
--- a/arch/s390/kernel/base.S
+++ b/arch/s390/kernel/base.S
@@ -78,15 +78,20 @@ s390_base_pgm_handler_fn:
#
# Calls diag 308 subcode 1 and continues execution
#
-# The following conditions must be ensured before calling this function:
-# * Prefix register = 0
-# * Lowcore protection is disabled
-#
ENTRY(diag308_reset)
larl %r4,.Lctlregs # Save control registers
stctg %c0,%c15,0(%r4)
+ lg %r2,0(%r4) # Disable lowcore protection
+ nilh %r2,0xefff
+ larl %r4,.Lctlreg0
+ stg %r2,0(%r4)
+ lctlg %c0,%c0,0(%r4)
larl %r4,.Lfpctl # Floating point control register
stfpc 0(%r4)
+ larl %r4,.Lprefix # Save prefix register
+ stpx 0(%r4)
+ larl %r4,.Lprefix_zero # Set prefix register to 0
+ spx 0(%r4)
larl %r4,.Lcontinue_psw # Save PSW flags
epsw %r2,%r3
stm %r2,%r3,0(%r4)
@@ -106,6 +111,8 @@ ENTRY(diag308_reset)
lctlg %c0,%c15,0(%r4)
larl %r4,.Lfpctl # Restore floating point ctl register
lfpc 0(%r4)
+ larl %r4,.Lprefix # Restore prefix register
+ spx 0(%r4)
larl %r4,.Lcontinue_psw # Restore PSW flags
lpswe 0(%r4)
.Lcontinue:
@@ -122,10 +129,16 @@ ENTRY(diag308_reset)
.section .bss
.align 8
+.Lctlreg0:
+ .quad 0
.Lctlregs:
.rept 16
.quad 0
.endr
.Lfpctl:
.long 0
+.Lprefix:
+ .long 0
+.Lprefix_zero:
+ .long 0
.previous