sparc64: Adjust __raw_local_irq_save() to cooperate in NMIs.

If we are in an NMI then doing a plain raw_local_irq_disable() will
write PIL_NORMAL_MAX into %pil, which is lower than PIL_NMI, and thus
we'll re-enable NMIs and recurse.

Doing a simple:

	%pil = %pil | PIL_NORMAL_MAX

does what we want, if we're already at PIL_NMI (15) we leave it at
that setting, else we set it to PIL_NORMAL_MAX (14).

This should get the function tracer working on sparc64.

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

1 files changed, 12 insertions, 2 deletions

diff --git a/arch/sparc/include/asm/irqflags_64.h b/arch/sparc/include/asm/irqflags_64.h
index 8b49bf920df3..a16e94c4b149 100644
--- a/arch/sparc/include/asm/irqflags_64.h
+++ b/arch/sparc/include/asm/irqflags_64.h
@@ -76,9 +76,19 @@ static inline int raw_irqs_disabled(void)
  */
 static inline unsigned long __raw_local_irq_save(void)
 {
-        unsigned long flags = __raw_local_save_flags();
+        unsigned long flags, tmp;
 
-        raw_local_irq_disable();
+        /* Disable interrupts to PIL_NORMAL_MAX unless we already
+         * are using PIL_NMI, in which case PIL_NMI is retained.
+         */
+        __asm__ __volatile__(
+                "rdpr   %%pil, %0\n\t"
+                "or     %0, %2, %1\n\t"
+                "wrpr   %1, 0x0, %%pil"
+                : "=r" (flags), "=r" (tmp)
+                : "i" (PIL_NORMAL_MAX)
+                : "memory"
+        );
 
         return flags;
 }