s390/mem_detect: fix lockdep irq tracing

When disabling and enabling interrupts we must tell lockdep.
So use local_irq_save()/restore() to disable and enable interrupts.
The DAT disabling/enabling get handled separately now.
Note: we may not call trace_hardirqs_on() with DAT disabled, since
the generic code may access vmalloc'ed data structures.

Reported-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/arch/s390/mm/mem_detect.c b/arch/s390/mm/mem_detect.c
index 22d502e885ed..fb216e11c25d 100644
--- a/arch/s390/mm/mem_detect.c
+++ b/arch/s390/mm/mem_detect.c
@@ -47,19 +47,21 @@ static void find_memory_chunks(struct mem_chunk chunk[])
 
 void detect_memory_layout(struct mem_chunk chunk[])
 {
-        unsigned long flags, cr0;
+        unsigned long flags, flags_dat, cr0;
 
         memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
         /* Disable IRQs, DAT and low address protection so tprot does the
          * right thing and we don't get scheduled away with low address
          * protection disabled.
          */
-        flags = __arch_local_irq_stnsm(0xf8);
+        local_irq_save(flags);
+        flags_dat = __arch_local_irq_stnsm(0xfb);
         __ctl_store(cr0, 0, 0);
         __ctl_clear_bit(0, 28);
         find_memory_chunks(chunk);
         __ctl_load(cr0, 0, 0);
-        arch_local_irq_restore(flags);
+        __arch_local_irq_ssm(flags_dat);
+        local_irq_restore(flags);
 }
 EXPORT_SYMBOL(detect_memory_layout);