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Diffstat (limited to 'arch/s390/kernel/entry64.S')
-rw-r--r--arch/s390/kernel/entry64.S57
1 files changed, 42 insertions, 15 deletions
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 5a4a7bcd2bba..fee10177dbfc 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -271,8 +271,6 @@ sysc_noemu:
stg %r2,SP_R2(%r15) # store return value (change R2 on stack)
sysc_return:
- tm SP_PSW+1(%r15),0x01 # returning to user ?
- jno sysc_restore
tm __TI_flags+7(%r9),_TIF_WORK_SVC
jnz sysc_work # there is work to do (signals etc.)
sysc_restore:
@@ -304,6 +302,8 @@ sysc_work_loop:
# One of the work bits is on. Find out which one.
#
sysc_work:
+ tm SP_PSW+1(%r15),0x01 # returning to user ?
+ jno sysc_restore
tm __TI_flags+7(%r9),_TIF_MCCK_PENDING
jo sysc_mcck_pending
tm __TI_flags+7(%r9),_TIF_NEED_RESCHED
@@ -585,12 +585,6 @@ io_no_vtime:
la %r2,SP_PTREGS(%r15) # address of register-save area
brasl %r14,do_IRQ # call standard irq handler
io_return:
- tm SP_PSW+1(%r15),0x01 # returning to user ?
-#ifdef CONFIG_PREEMPT
- jno io_preempt # no -> check for preemptive scheduling
-#else
- jno io_restore # no-> skip resched & signal
-#endif
tm __TI_flags+7(%r9),_TIF_WORK_INT
jnz io_work # there is work to do (signals etc.)
io_restore:
@@ -612,10 +606,41 @@ io_restore_trace_psw:
.quad 0, io_restore_trace
#endif
-#ifdef CONFIG_PREEMPT
-io_preempt:
+#
+# There is work todo, we need to check if we return to userspace, then
+# check, if we are in SIE, if yes leave it
+#
+io_work:
+ tm SP_PSW+1(%r15),0x01 # returning to user ?
+#ifndef CONFIG_PREEMPT
+#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
+ jnz io_work_user # yes -> no need to check for SIE
+ la %r1, BASED(sie_opcode) # we return to kernel here
+ lg %r2, SP_PSW+8(%r15)
+ clc 0(2,%r1), 0(%r2) # is current instruction = SIE?
+ jne io_restore # no-> return to kernel
+ lg %r1, SP_PSW+8(%r15) # yes-> add 4 bytes to leave SIE
+ aghi %r1, 4
+ stg %r1, SP_PSW+8(%r15)
+ j io_restore # return to kernel
+#else
+ jno io_restore # no-> skip resched & signal
+#endif
+#else
+ jnz io_work_user # yes -> do resched & signal
+#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
+ la %r1, BASED(sie_opcode)
+ lg %r2, SP_PSW+8(%r15)
+ clc 0(2,%r1), 0(%r2) # is current instruction = SIE?
+ jne 0f # no -> leave PSW alone
+ lg %r1, SP_PSW+8(%r15) # yes-> add 4 bytes to leave SIE
+ aghi %r1, 4
+ stg %r1, SP_PSW+8(%r15)
+0:
+#endif
+ # check for preemptive scheduling
icm %r0,15,__TI_precount(%r9)
- jnz io_restore
+ jnz io_restore # preemption is disabled
# switch to kernel stack
lg %r1,SP_R15(%r15)
aghi %r1,-SP_SIZE
@@ -629,10 +654,7 @@ io_resume_loop:
jg preempt_schedule_irq
#endif
-#
-# switch to kernel stack, then check TIF bits
-#
-io_work:
+io_work_user:
lg %r1,__LC_KERNEL_STACK
aghi %r1,-SP_SIZE
mvc SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
@@ -653,6 +675,11 @@ io_work_loop:
j io_restore
io_work_done:
+#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
+sie_opcode:
+ .long 0xb2140000
+#endif
+
#
# _TIF_MCCK_PENDING is set, call handler
#