[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/entry.S b/arch/s390/kernel/entry.S
index 48215d1..e8ef21c 100644 (file)
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -571,6 +571,7 @@ pgm_svcper:
        mvc     __THREAD_per+__PER_access_id(1,%r8),__LC_PER_ACCESS_ID
        oi      __TI_flags+3(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
        TRACE_IRQS_ON
+       lm      %r2,%r6,SP_R2(%r15)     # load svc arguments
        stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
        b       BASED(sysc_do_svc)
 

diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 9aff1d4..f33658f 100644 (file)
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -549,6 +549,7 @@ pgm_svcper:
        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