[S390] fix single stepped svcs with TRACE_IRQFLAGS=y
If irq flags tracing is enabled the TRACE_IRQS_ON macros expands to
a function call which clobbers registers %r0-%r5. The macro is used
in the code path for single stepped system calls. The argument
registers %r2-%r6 need to be restored from the stack before the system
call function is called.
Cc: stable@kernel.org
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 9aff1d4..f33658f 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -549,6 +549,7 @@
mvc __THREAD_per+__PER_access_id(1,%r8),__LC_PER_ACCESS_ID
oi __TI_flags+7(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
TRACE_IRQS_ON
+ lmg %r2,%r6,SP_R2(%r15) # load svc arguments
stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
j sysc_do_svc