From: AMEET M. PARANJAPE <aparanja@redhat.com>
Date: Thu, 8 Jan 2009 11:46:19 -0500
Subject: [ppc64] cell: fix npc setting for NOSCHED contexts
Message-id: 20090108164521.29017.96385.sendpatchset@squad5-lp1.lab.bos.redhat.com
O-Subject: [PATCH RHEL5.4 BZ467344] Fix npc setting for NOSCHED contexts
Bugzilla: 467344
RH-Acked-by: David Howells <dhowells@redhat.com>

RHBZ#:
======
https://bugzilla.redhat.com/show_bug.cgi?id=467344

Description:
===========
Currently, spu_run ignores the npc argument for contexts created with
SPU_CREATE_NOSCHED. While this is correct for isolated contexts,
there's no need to enforce the npc restriction on non-isolated NOSCHED
contexts.

This means that NOSCHED contexts can only ever run with an entry point
of 0x0.

This change to spu_run_init allows setting of the npc (and, while we're
at it, the privcntl) for non-isolated NOSCHED contexts. This allows
us to run NOSCHED contexts from any entry point.

RHEL Version Found:
================
RHEL 5.3

kABI Status:
============
No symbols were harmed.

Brew:
=====
Built on all platforms.
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1642053

Upstream Status:
================
commit d9dd421fd6ed17af55d27c8d93a9f561be0ff50f

Test Status:
============
Run the testcase binary given in the Bugzilla.  Without the patch the testcase
fails, but doesn't with the patch applied.
===============================================================
Ameet Paranjape 978-392-3903 ext 23903
IBM on-site partner

Proposed Patch:
===============

diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c
index 395da1a..ffa18ad 100644
--- a/arch/powerpc/platforms/cell/spufs/run.c
+++ b/arch/powerpc/platforms/cell/spufs/run.c
@@ -203,11 +203,6 @@ static int spu_run_init(struct spu_context *ctx, u32 *npc)
 			(SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
 		if (runcntl == 0)
 			runcntl = SPU_RUNCNTL_RUNNABLE;
-	}
-
-	if (ctx->flags & SPU_CREATE_NOSCHED) {
-		spuctx_switch_state(ctx, SPU_UTIL_USER);
-		ctx->ops->runcntl_write(ctx, runcntl);
 	} else {
 		unsigned long privcntl;
 
@@ -216,9 +211,15 @@ static int spu_run_init(struct spu_context *ctx, u32 *npc)
 		else
 			privcntl = SPU_PRIVCNTL_MODE_NORMAL;
 
-		ctx->ops->npc_write(ctx, *npc);
 		ctx->ops->privcntl_write(ctx, privcntl);
-		ctx->ops->runcntl_write(ctx, runcntl);
+		ctx->ops->npc_write(ctx, *npc);
+	}
+
+	ctx->ops->runcntl_write(ctx, runcntl);
+
+	if (ctx->flags & SPU_CREATE_NOSCHED) {
+		spuctx_switch_state(ctx, SPU_UTIL_USER);
+	} else {
 
 		if (ctx->state == SPU_STATE_SAVED) {
 			ret = spu_activate(ctx, 0);