sparc64: Make special trap return path for TRAP_NMI().

We don't want the rtrap path to try and run softirqs or
anything like that when returning from a PIL==15 NMI.

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

diff --git a/arch/sparc/include/asm/ttable.h b/arch/sparc/include/asm/ttable.h
index bb2c077..48f2807 100644 (file)
--- a/arch/sparc/include/asm/ttable.h
+++ b/arch/sparc/include/asm/ttable.h
@@ -162,7 +162,7 @@
        mov     level, %o0;                             \
        call    routine;                                \
         add    %sp, PTREGS_OFF, %o1;                   \
-       ba,a,pt %xcc, rtrap_irq;
+       ba,a,pt %xcc, rtrap_nmi;
 
 #define TRAP_IVEC TRAP_NOSAVE(do_ivec)
 

diff --git a/arch/sparc64/kernel/rtrap.S b/arch/sparc64/kernel/rtrap.S
index 6892cf5..fd3cee4 100644 (file)
--- a/arch/sparc64/kernel/rtrap.S
+++ b/arch/sparc64/kernel/rtrap.S
@@ -132,6 +132,18 @@ __handle_signal:
                ba,pt                   %xcc, __handle_signal_continue
                 andn                   %l1, %l4, %l1
 
+               /* When returning from a NMI (%pil==15) interrupt we want to
+                * avoid running softirqs, doing IRQ tracing, preempting, etc.
+                */
+               .globl                  rtrap_nmi
+rtrap_nmi:     ldx                     [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
+               sethi                   %hi(0xf << 20), %l4
+               and                     %l1, %l4, %l4
+               andn                    %l1, %l4, %l1
+               srl                     %l4, 20, %l4
+               ba,pt                   %xcc, rtrap_no_irq_enable
+                wrpr                   %l4, %pil
+
                .align                  64
                .globl                  rtrap_irq, rtrap, irqsz_patchme, rtrap_xcall
 rtrap_irq:
@@ -161,8 +173,8 @@ rtrap_xcall:
                call                    trace_hardirqs_on
                 nop
                wrpr                    %l4, %pil
-rtrap_no_irq_enable:
 #endif
+rtrap_no_irq_enable:
                andcc                   %l1, TSTATE_PRIV, %l3
                bne,pn                  %icc, to_kernel
                 nop