arch/tile: avoid accidentally unmasking NMI-type interrupt accidentally

The return path as we reload registers and core state requires that r30
hold a boolean indicating whether we are returning from an NMI, but in a
couple of cases we weren't setting this properly, with the result that we
could accidentally unmask the NMI interrupt(s), which could cause confusion.
Now we set r30 in every place where we jump into the interrupt return path.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

diff --git a/arch/tile/kernel/intvec_32.S b/arch/tile/kernel/intvec_32.S
index aecc8ed5f39bd71d48cb150fe30301425b2179b7..5d56a1ef5ba5212e6cffe97e0fe14223bc0d116b 100644 (file)
--- a/arch/tile/kernel/intvec_32.S
+++ b/arch/tile/kernel/intvec_32.S
@@ -799,6 +799,10 @@ handle_interrupt:
  * This routine takes a boolean in r30 indicating if this is an NMI.
  * If so, we also expect a boolean in r31 indicating whether to
  * re-enable the oprofile interrupts.
+ *
+ * Note that .Lresume_userspace is jumped to directly in several
+ * places, and we need to make sure r30 is set correctly in those
+ * callers as well.
  */
 STD_ENTRY(interrupt_return)
        /* If we're resuming to kernel space, don't check thread flags. */
@@ -1237,7 +1241,10 @@ handle_syscall:
        bzt     r30, 1f
        jal     do_syscall_trace
        FEEDBACK_REENTER(handle_syscall)
-1:     j       .Lresume_userspace   /* jump into middle of interrupt_return */
+1:     {
+        movei  r30, 0               /* not an NMI */
+        j      .Lresume_userspace   /* jump into middle of interrupt_return */
+       }
 
 .Linvalid_syscall:
        /* Report an invalid syscall back to the user program */
@@ -1246,7 +1253,10 @@ handle_syscall:
         movei  r28, -ENOSYS
        }
        sw      r29, r28
-       j       .Lresume_userspace   /* jump into middle of interrupt_return */
+       {
+        movei  r30, 0               /* not an NMI */
+        j      .Lresume_userspace   /* jump into middle of interrupt_return */
+       }
        STD_ENDPROC(handle_syscall)
 
        /* Return the address for oprofile to suppress in backtraces. */
@@ -1262,7 +1272,10 @@ STD_ENTRY(ret_from_fork)
        jal     sim_notify_fork
        jal     schedule_tail
        FEEDBACK_REENTER(ret_from_fork)
-       j       .Lresume_userspace   /* jump into middle of interrupt_return */
+       {
+        movei  r30, 0               /* not an NMI */
+        j      .Lresume_userspace   /* jump into middle of interrupt_return */
+       }
        STD_ENDPROC(ret_from_fork)
 
        /*
@@ -1376,7 +1389,10 @@ handle_ill:
 
        jal     send_sigtrap    /* issue a SIGTRAP */
        FEEDBACK_REENTER(handle_ill)
-       j       .Lresume_userspace   /* jump into middle of interrupt_return */
+       {
+        movei  r30, 0               /* not an NMI */
+        j      .Lresume_userspace   /* jump into middle of interrupt_return */
+       }
 
 .Ldispatch_normal_ill:
        {

diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index fdff17c70cc888a320e82f4c7dcd5f684b8bdd9c..49d9d66216822a463a4e905f3425e8eb2a4f77e8 100644 (file)
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -606,6 +606,10 @@ handle_interrupt:
  * This routine takes a boolean in r30 indicating if this is an NMI.
  * If so, we also expect a boolean in r31 indicating whether to
  * re-enable the oprofile interrupts.
+ *
+ * Note that .Lresume_userspace is jumped to directly in several
+ * places, and we need to make sure r30 is set correctly in those
+ * callers as well.
  */
 STD_ENTRY(interrupt_return)
        /* If we're resuming to kernel space, don't check thread flags. */
@@ -1058,7 +1062,10 @@ handle_syscall:
        }
        FEEDBACK_REENTER(handle_syscall)
 
-2:     j       .Lresume_userspace   /* jump into middle of interrupt_return */
+2:     {
+        movei  r30, 0               /* not an NMI */
+        j      .Lresume_userspace   /* jump into middle of interrupt_return */
+       }
 
 .Lcompat_syscall:
        /*
@@ -1092,7 +1099,10 @@ handle_syscall:
         movei  r28, -ENOSYS
        }
        st      r29, r28
-       j       .Lresume_userspace   /* jump into middle of interrupt_return */
+       {
+        movei  r30, 0               /* not an NMI */
+        j      .Lresume_userspace   /* jump into middle of interrupt_return */
+       }
        STD_ENDPROC(handle_syscall)
 
        /* Return the address for oprofile to suppress in backtraces. */
@@ -1108,7 +1118,10 @@ STD_ENTRY(ret_from_fork)
        jal     sim_notify_fork
        jal     schedule_tail
        FEEDBACK_REENTER(ret_from_fork)
-       j       .Lresume_userspace
+       {
+        movei  r30, 0               /* not an NMI */
+        j      .Lresume_userspace   /* jump into middle of interrupt_return */
+       }
        STD_ENDPROC(ret_from_fork)
 
 /* Various stub interrupt handlers and syscall handlers */