Subject: implement error event delivery to user space

This tries to fix spufs so we have an interface closer
to what is specified in the man page for events
returned in the third argument of spu_run.

Fortunately, libspe has never been using the returned
contents of that register, as they were the same
as the return code of spu_run (duh!).

This returns what we need from libspe, but only
when a flag was set on spu_create. Now that flag
was previously not documented, so we're actually
extending the semantics here.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Index: linus-2.6/arch/powerpc/platforms/cell/spu_base.c
===================================================================
--- linus-2.6.orig/arch/powerpc/platforms/cell/spu_base.c
+++ linus-2.6/arch/powerpc/platforms/cell/spu_base.c
@@ -46,21 +46,21 @@ EXPORT_SYMBOL_GPL(spu_priv1_ops);
 static int __spu_trap_invalid_dma(struct spu *spu)
 {
 	pr_debug("%s\n", __FUNCTION__);
-	force_sig(SIGBUS, /* info, */ current);
+	spu->dma_callback(spu, SPE_EVENT_INVALID_DMA);
 	return 0;
 }
 
 static int __spu_trap_dma_align(struct spu *spu)
 {
 	pr_debug("%s\n", __FUNCTION__);
-	force_sig(SIGBUS, /* info, */ current);
+	spu->dma_callback(spu, SPE_EVENT_DMA_ALIGNMENT);
 	return 0;
 }
 
 static int __spu_trap_error(struct spu *spu)
 {
 	pr_debug("%s\n", __FUNCTION__);
-	force_sig(SIGILL, /* info, */ current);
+	spu->dma_callback(spu, SPE_EVENT_SPE_ERROR);
 	return 0;
 }
 
Index: linus-2.6/arch/powerpc/platforms/cell/spufs/inode.c
===================================================================
--- linus-2.6.orig/arch/powerpc/platforms/cell/spufs/inode.c
+++ linus-2.6/arch/powerpc/platforms/cell/spufs/inode.c
@@ -225,7 +225,8 @@ struct file_operations spufs_context_fop
 };
 
 static int
-spufs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,
+		int mode)
 {
 	int ret;
 	struct inode *inode;
@@ -245,6 +246,8 @@ spufs_mkdir(struct inode *dir, struct de
 	if (!ctx)
 		goto out_iput;
 
+	ctx->flags = flags;
+
 	inode->i_op = &spufs_dir_inode_operations;
 	inode->i_fop = &simple_dir_operations;
 	ret = spufs_fill_dir(dentry, spufs_dir_contents, mode, ctx);
@@ -305,7 +308,7 @@ long spufs_create_thread(struct nameidat
 		goto out;
 
 	/* all flags are reserved */
-	if (flags)
+	if (flags & (~SPU_CREATE_FLAG_ALL))
 		goto out;
 
 	dentry = lookup_create(nd, 1);
@@ -318,7 +321,7 @@ long spufs_create_thread(struct nameidat
 		goto out_dput;
 
 	mode &= ~current->fs->umask;
-	ret = spufs_mkdir(nd->dentry->d_inode, dentry, mode & S_IRWXUGO);
+	ret = spufs_mkdir(nd->dentry->d_inode, dentry, flags, mode & S_IRWXUGO);
 	if (ret)
 		goto out_dput;
 
Index: linus-2.6/arch/powerpc/platforms/cell/spufs/run.c
===================================================================
--- linus-2.6.orig/arch/powerpc/platforms/cell/spufs/run.c
+++ linus-2.6/arch/powerpc/platforms/cell/spufs/run.c
@@ -13,6 +13,26 @@ void spufs_stop_callback(struct spu *spu
 	wake_up_all(&ctx->stop_wq);
 }
 
+void spufs_dma_callback(struct spu *spu, int type)
+{
+	struct spu_context *ctx = spu->ctx;
+
+	if (ctx->flags & SPU_CREATE_EVENTS_ENABLED) {
+		ctx->event_return |= type;
+		wake_up_all(&ctx->stop_wq);
+	} else {
+		switch (type) {
+		case SPE_EVENT_DMA_ALIGNMENT:
+		case SPE_EVENT_INVALID_DMA:
+			force_sig(SIGBUS, /* info, */ current);
+			break;
+		case SPE_EVENT_SPE_ERROR:
+			force_sig(SIGILL, /* info */ current);
+			break;
+		}
+	}
+}
+
 static inline int spu_stopped(struct spu_context *ctx, u32 * stat)
 {
 	struct spu *spu;
@@ -27,8 +47,7 @@ static inline int spu_stopped(struct spu
 	return (!(*stat & 0x1) || pte_fault || spu->class_0_pending) ? 1 : 0;
 }
 
-static inline int spu_run_init(struct spu_context *ctx, u32 * npc,
-			       u32 * status)
+static inline int spu_run_init(struct spu_context *ctx, u32 * npc)
 {
 	int ret;
 
@@ -71,7 +90,7 @@ static inline int spu_reacquire_runnable
 		       SPU_STATUS_STOPPED_BY_HALT)) {
 		return *status;
 	}
-	if ((ret = spu_run_init(ctx, npc, status)) != 0)
+	if ((ret = spu_run_init(ctx, npc)) != 0)
 		return ret;
 	return 0;
 }
@@ -176,46 +195,49 @@ static inline int spu_process_events(str
 }
 
 long spufs_run_spu(struct file *file, struct spu_context *ctx,
-		   u32 * npc, u32 * status)
+		   u32 *npc, u32 *event)
 {
 	int ret;
+	u32 status;
 
 	if (down_interruptible(&ctx->run_sema))
 		return -ERESTARTSYS;
 
-	ret = spu_run_init(ctx, npc, status);
+	ctx->event_return = 0;
+	ret = spu_run_init(ctx, npc);
 	if (ret)
 		goto out;
 
 	do {
-		ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, status));
+		ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
 		if (unlikely(ret))
 			break;
-		if ((*status & SPU_STATUS_STOPPED_BY_STOP) &&
-		    (*status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
+		if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
+		    (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
 			ret = spu_process_callback(ctx);
 			if (ret)
 				break;
-			*status &= ~SPU_STATUS_STOPPED_BY_STOP;
+			status &= ~SPU_STATUS_STOPPED_BY_STOP;
 		}
 		if (unlikely(ctx->state != SPU_STATE_RUNNABLE)) {
-			ret = spu_reacquire_runnable(ctx, npc, status);
+			ret = spu_reacquire_runnable(ctx, npc, &status);
 			if (ret)
 				goto out;
 			continue;
 		}
 		ret = spu_process_events(ctx);
 
-	} while (!ret && !(*status & (SPU_STATUS_STOPPED_BY_STOP |
+	} while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
 				      SPU_STATUS_STOPPED_BY_HALT)));
 
 	ctx->ops->runcntl_stop(ctx);
-	ret = spu_run_fini(ctx, npc, status);
+	ret = spu_run_fini(ctx, npc, &status);
 	if (!ret)
-		ret = *status;
+		ret = status;
 	spu_yield(ctx);
 
 out:
+	*event = ctx->event_return;
 	up(&ctx->run_sema);
 	return ret;
 }
Index: linus-2.6/arch/powerpc/platforms/cell/spufs/sched.c
===================================================================
--- linus-2.6.orig/arch/powerpc/platforms/cell/spufs/sched.c
+++ linus-2.6/arch/powerpc/platforms/cell/spufs/sched.c
@@ -117,7 +117,6 @@ static inline void bind_context(struct s
 		 spu->number, spu->node);
 	spu->ctx = ctx;
 	spu->flags = 0;
-	ctx->flags = 0;
 	ctx->spu = spu;
 	ctx->ops = &spu_hw_ops;
 	spu->pid = current->pid;
@@ -128,6 +127,7 @@ static inline void bind_context(struct s
 	spu->wbox_callback = spufs_wbox_callback;
 	spu->stop_callback = spufs_stop_callback;
 	spu->mfc_callback = spufs_mfc_callback;
+	spu->dma_callback = spufs_dma_callback;
 	mb();
 	spu_unmap_mappings(ctx);
 	spu_restore(&ctx->csa, spu);
@@ -149,12 +149,12 @@ static inline void unbind_context(struct
 	spu->wbox_callback = NULL;
 	spu->stop_callback = NULL;
 	spu->mfc_callback = NULL;
+	spu->dma_callback = NULL;
 	spu->mm = NULL;
 	spu->pid = 0;
 	spu->prio = MAX_PRIO;
 	ctx->ops = &spu_backing_ops;
 	ctx->spu = NULL;
-	ctx->flags = 0;
 	spu->flags = 0;
 	spu->ctx = NULL;
 }
Index: linus-2.6/arch/powerpc/platforms/cell/spufs/spufs.h
===================================================================
--- linus-2.6.orig/arch/powerpc/platforms/cell/spufs/spufs.h
+++ linus-2.6/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -67,7 +67,8 @@ struct spu_context {
 	u32 tagwait;
 	struct spu_context_ops *ops;
 	struct work_struct reap_work;
-	u64 flags;
+	unsigned long flags;
+	unsigned long event_return;
 };
 
 struct mfc_dma_command {
@@ -184,5 +185,6 @@ void spufs_ibox_callback(struct spu *spu
 void spufs_wbox_callback(struct spu *spu);
 void spufs_stop_callback(struct spu *spu);
 void spufs_mfc_callback(struct spu *spu);
+void spufs_dma_callback(struct spu *spu, int type);
 
 #endif
Index: linus-2.6/include/asm-powerpc/spu.h
===================================================================
--- linus-2.6.orig/include/asm-powerpc/spu.h
+++ linus-2.6/include/asm-powerpc/spu.h
@@ -138,6 +138,7 @@ struct spu {
 	void (* ibox_callback)(struct spu *spu);
 	void (* stop_callback)(struct spu *spu);
 	void (* mfc_callback)(struct spu *spu);
+	void (* dma_callback)(struct spu *spu, int type);
 
 	char irq_c0[8];
 	char irq_c1[8];
@@ -169,6 +170,19 @@ extern struct spufs_calls {
 	struct module *owner;
 } spufs_calls;
 
+/* return status from spu_run, same as in libspe */
+#define SPE_EVENT_DMA_ALIGNMENT		0x0008	/*A DMA alignment error */
+#define SPE_EVENT_SPE_ERROR		0x0010	/*An illegal instruction error*/
+#define SPE_EVENT_SPE_DATA_SEGMENT	0x0020	/*A DMA segmentation error    */
+#define SPE_EVENT_SPE_DATA_STORAGE	0x0040	/*A DMA storage error */
+#define SPE_EVENT_INVALID_DMA		0x0800	/* Invalid MFC DMA */
+
+/*
+ * Flags for sys_spu_create.
+ */
+#define SPU_CREATE_EVENTS_ENABLED	0x0001
+#define SPU_CREATE_FLAG_ALL		0x0001 /* mask of all valid flags */
+
 #ifdef CONFIG_SPU_FS_MODULE
 int register_spu_syscalls(struct spufs_calls *calls);
 void unregister_spu_syscalls(struct spufs_calls *calls);
Index: linus-2.6/arch/powerpc/platforms/cell/spufs/syscalls.c
===================================================================
--- linus-2.6.orig/arch/powerpc/platforms/cell/spufs/syscalls.c
+++ linus-2.6/arch/powerpc/platforms/cell/spufs/syscalls.c
@@ -38,7 +38,7 @@ static long do_spu_run(struct file *filp
 	u32 npc, status;
 
 	ret = -EFAULT;
-	if (get_user(npc, unpc) || get_user(status, ustatus))
+	if (get_user(npc, unpc))
 		goto out;
 
 	/* check if this file was created by spu_create */
@@ -49,7 +49,10 @@ static long do_spu_run(struct file *filp
 	i = SPUFS_I(filp->f_dentry->d_inode);
 	ret = spufs_run_spu(filp, i->i_ctx, &npc, &status);
 
-	if (put_user(npc, unpc) || put_user(status, ustatus))
+	if (put_user(npc, unpc))
+		ret = -EFAULT;
+
+	if (ustatus && put_user(status, ustatus))
 		ret = -EFAULT;
 out:
 	return ret;