[PATCH] spufs: cooperative scheduler support

This adds a scheduler for SPUs to make it possible to use
more logical SPUs than physical ones are present in the
system.

Currently, there is no support for preempting a running
SPU thread, they have to leave the SPU by either triggering
an event on the SPU that causes it to return to the
owning thread or by sending a signal to it.

This patch also adds operations that enable accessing an SPU
in either runnable or saved state. We use an RW semaphore
to protect the state of the SPU from changing underneath
us, while we are holding it readable. In order to change
the state, it is acquired writeable and a context save
or restore is executed before downgrading the semaphore
to read-only.

From: Mark Nutter <mnutter@us.ibm.com>,
      Uli Weigand <Ulrich.Weigand@de.ibm.com>
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 8 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/syscalls.c b/arch/powerpc/platforms/cell/spufs/syscalls.c
index 3f71bb5e9d8e..17a2b51c94bc 100644
--- a/arch/powerpc/platforms/cell/spufs/syscalls.c
+++ b/arch/powerpc/platforms/cell/spufs/syscalls.c
@@ -36,7 +36,7 @@ long do_spu_run(struct file *filp, __u32 __user *unpc, __u32 __user *ustatus)
 	u32 npc, status;
 
 	ret = -EFAULT;
-	if (get_user(npc, unpc))
+	if (get_user(npc, unpc) || get_user(status, ustatus))
 		goto out;
 
 	ret = -EINVAL;
@@ -46,13 +46,7 @@ long do_spu_run(struct file *filp, __u32 __user *unpc, __u32 __user *ustatus)
 	i = SPUFS_I(filp->f_dentry->d_inode);
 	ret = spufs_run_spu(filp, i->i_ctx, &npc, &status);
 
-	if (ret ==-EAGAIN || ret == -EIO)
-		ret = status;
-
-	if (put_user(npc, unpc))
-		ret = -EFAULT;
-
-	if (ustatus && put_user(status, ustatus))
+	if (put_user(npc, unpc) || put_user(status, ustatus))
 		ret = -EFAULT;
 out:
 	return ret;