sparc64: Make %pil level 15 a pseudo-NMI.

So that we can profile code even in a local_irq_disable() section,
only write 14 (instead of 15) into the %pil register to disable IRQs.

This allows PIL level 15 to serve as a pseudo NMI.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/sparc/include/asm/pil.h b/arch/sparc/include/asm/pil.h
index 71819bb943fc..d573820c0ff4 100644
--- a/arch/sparc/include/asm/pil.h
+++ b/arch/sparc/include/asm/pil.h
@@ -10,7 +10,12 @@
  *
  * In fact any XCALL which has to etrap/rtrap has a problem because
  * it is difficult to prevent rtrap from running BH's, and that would
- * need to be done if the XCALL arrived while %pil==15.
+ * need to be done if the XCALL arrived while %pil==PIL_NORMAL_MAX.
+ *
+ * Finally, in order to handle profiling events even when a
+ * local_irq_disable() is in progress, we only disable up to level 14
+ * interrupts.  Profile counter overflow interrupts arrive at level
+ * 15.
  */
 #define PIL_SMP_CALL_FUNC       1
 #define PIL_SMP_RECEIVE_SIGNAL  2
@@ -18,5 +23,7 @@
 #define PIL_SMP_CTX_NEW_VERSION 4
 #define PIL_DEVICE_IRQ          5
 #define PIL_SMP_CALL_FUNC_SNGL  6
+#define PIL_NORMAL_MAX          14
+#define PIL_NMI                 15
 
 #endif /* !(_SPARC64_PIL_H) */