[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>

1 files changed, 10 insertions, 2 deletions

diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index d5e3e6007447..bea9ee37ac9d 100644
--- a/arch/s390/kernel/entry.S
+++ b/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