[S390] Fix IRQ tracing in case of PER

In case user space is single stepped (PER) the program check handler
claims too early that IRQs are enabled on the return path.
Subsequent checks will notice that the IRQ mask in the PSW and
what lockdep thinks the IRQ mask should be do not correlate and
therefore will print a warning to the console and disable lockdep.

Fix this by doing all the work within the correct context.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/entry.S

@@ -535,8 +535,16 @@ pgm_no_vtime2:
 	l	%r3,__LC_PGM_ILC	# load program interruption code
 	la	%r8,0x7f
 	nr	%r8,%r3 		# clear per-event-bit and ilc
-	be	BASED(pgm_exit)		# only per or per+check ?
-	b	BASED(pgm_do_call)
+	be	BASED(pgm_exit2)	# only per or per+check ?
+	l	%r7,BASED(.Ljump_table)
+	sll	%r8,2
+	l	%r7,0(%r8,%r7)		# load address of handler routine
+	la	%r2,SP_PTREGS(%r15)	# address of register-save area
+	basr	%r14,%r7		# branch to interrupt-handler
+pgm_exit2:
+	TRACE_IRQS_ON
+	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
+	b	BASED(sysc_return)
 
 #
 # it was a single stepped SVC that is causing all the trouble

arch/s390/kernel/entry64.S

@@ -544,8 +544,16 @@ pgm_no_vtime2:
 	lgf	%r3,__LC_PGM_ILC	# load program interruption code
 	lghi	%r8,0x7f
 	ngr	%r8,%r3			# clear per-event-bit and ilc
-	je	pgm_exit
-	j	pgm_do_call
+	je	pgm_exit2
+	sll	%r8,3
+	larl	%r1,pgm_check_table
+	lg	%r1,0(%r8,%r1)		# load address of handler routine
+	la	%r2,SP_PTREGS(%r15)	# address of register-save area
+	basr	%r14,%r1		# branch to interrupt-handler
+pgm_exit2:
+	TRACE_IRQS_ON
+	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
+	j	sysc_return
 
 #
 # it was a single stepped SVC that is causing all the trouble