[Cbe-oss-dev] [PATCH 4:10] spufs: remove class_0_dsisr from spu exception handling.

[Luke Browning]

Remove class_0_dsisr from spu exception handling.

According to the CBEA, the dsisr is not updated for class 0 
exceptions.  The value of the register is unarchitected for
class 0 exceptions.  spu_stopped() is testing the dsisr that
was passed to it from the class 0 exception handler and the
test that it is making is for a class 1 exception!  

This patch cleans up the interrupt handler and erroneous 
tests in spu_stopped.  It also removes the fields from the
csa since it is not needed to process class 0 events.

Signed-off-by: Luke Browning <lukebrowning at us.ibm.com>

---

Index: linux-2.6.25/arch/powerpc/platforms/cell/spu_base.c
===================================================================
--- linux-2.6.25.orig/arch/powerpc/platforms/cell/spu_base.c
+++ linux-2.6.25/arch/powerpc/platforms/cell/spu_base.c
@@ -324,14 +324,12 @@ spu_irq_class_0(int irq, void *data)
 	stat = spu_int_stat_get(spu, 0) & mask;
 
 	spu->class_0_pending |= stat;
-	spu->class_0_dsisr = spu_mfc_dsisr_get(spu);
 	spu->class_0_dar = spu_mfc_dar_get(spu);
 	spin_unlock(&spu->register_lock);
 
 	spu->stop_callback(spu, 0);
 
 	spu->class_0_pending = 0;
-	spu->class_0_dsisr = 0;
 	spu->class_0_dar = 0;
 
 	spu_int_stat_clear(spu, 0, stat);
@@ -373,9 +371,6 @@ spu_irq_class_1(int irq, void *data)
 	if (stat & CLASS1_LS_COMPARE_SUSPEND_ON_PUT_INTR)
 		;
 
-	spu->class_1_dsisr = 0;
-	spu->class_1_dar = 0;
-
 	return stat ? IRQ_HANDLED : IRQ_NONE;
 }
 
Index: linux-2.6.25/arch/powerpc/platforms/cell/spufs/run.c
===================================================================
--- linux-2.6.25.orig/arch/powerpc/platforms/cell/spufs/run.c
+++ linux-2.6.25/arch/powerpc/platforms/cell/spufs/run.c
@@ -27,7 +27,6 @@ void spufs_stop_callback(struct spu *spu
 		switch(irq) {
 		case 0 :
 			ctx->csa.class_0_pending = spu->class_0_pending;
-			ctx->csa.class_0_dsisr = spu->class_0_dsisr;
 			ctx->csa.class_0_dar = spu->class_0_dar;
 			break;
 		case 1 :
@@ -35,11 +34,19 @@ void spufs_stop_callback(struct spu *spu
 			ctx->csa.class_1_dar = spu->class_1_dar;
 			break;
 		case 2 :
+			/*
+			 * No arguments need to be passed.  The delivery of the
+			 * event is synchronous wrt the controlling thread which
+			 * reads the spu status register to determine the nature
+			 * of the event, stop-n-signal, ...
+			 */
 			break;
 		}
 
-		/* ensure that the exception status has hit memory before a
-		 * thread waiting on the context's stop queue is woken */
+		/*
+		 * Ensure that the exception status has hit memory before a
+		 * thread waiting on the context's stop queue is woken
+		 */
 		smp_wmb();
 
 		wake_up_all(&ctx->stop_wq);
@@ -72,10 +79,6 @@ top:
 	if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
 		return 1;
 
-	dsisr = ctx->csa.class_0_dsisr;
-	if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))
-		return 1;
-
 	dsisr = ctx->csa.class_1_dsisr;
 	if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))
 		return 1;
Index: linux-2.6.25/arch/powerpc/xmon/xmon.c
===================================================================
--- linux-2.6.25.orig/arch/powerpc/xmon/xmon.c
+++ linux-2.6.25/arch/powerpc/xmon/xmon.c
@@ -2844,7 +2844,6 @@ static void dump_spu_fields(struct spu *
 	DUMP_FIELD(spu, "0x%lx", flags);
 	DUMP_FIELD(spu, "%d", class_0_pending);
 	DUMP_FIELD(spu, "0x%lx", class_0_dar);
-	DUMP_FIELD(spu, "0x%lx", class_0_dsisr);
 	DUMP_FIELD(spu, "0x%lx", class_1_dar);
 	DUMP_FIELD(spu, "0x%lx", class_1_dsisr);
 	DUMP_FIELD(spu, "0x%lx", irqs[0]);
Index: linux-2.6.25/include/asm-powerpc/spu.h
===================================================================
--- linux-2.6.25.orig/include/asm-powerpc/spu.h
+++ linux-2.6.25/include/asm-powerpc/spu.h
@@ -131,7 +131,6 @@ struct spu {
 	u64 flags;
 	u64 class_0_pending;
 	u64 class_0_dar;
-	u64 class_0_dsisr;
 	u64 class_1_dar;
 	u64 class_1_dsisr;
 	size_t ls_size;
Index: linux-2.6.25/include/asm-powerpc/spu_csa.h
===================================================================
--- linux-2.6.25.orig/include/asm-powerpc/spu_csa.h
+++ linux-2.6.25/include/asm-powerpc/spu_csa.h
@@ -254,7 +254,7 @@ struct spu_state {
 	u64 spu_chnldata_RW[32];
 	u32 spu_mailbox_data[4];
 	u32 pu_mailbox_data[1];
-	u64 class_0_dar, class_0_dsisr, class_0_pending;
+	u64 class_0_dar, class_0_pending;
 	u64 class_1_dar, class_1_dsisr;
 	unsigned long suspend_time;
 	spinlock_t register_lock;