Merge git://git.infradead.org/~dwmw2/random-2.6

[pandora-kernel.git] / arch / s390 / kernel / entry64.S

diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 5a4a7bc..fee1017 100644 (file)
--- 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
 #