[POWERPC] spufs: add support for nonschedulable contexts

This adds two new flags to spu_create:

SPU_CREATE_NONSCHED: create a context that is never moved
away from an SPE once it has started running. This flag
can only be used by tasks with the CAP_SYS_NICE capability.

SPU_CREATE_ISOLATED: create a nonschedulable context that
enters isolation mode upon first run. This requires the
SPU_CREATE_NONSCHED flag.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 48 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/switch.c b/arch/powerpc/platforms/cell/spufs/switch.c
index b85347ff6b22..b47fb50ac2c1 100644
--- a/arch/powerpc/platforms/cell/spufs/switch.c
+++ b/arch/powerpc/platforms/cell/spufs/switch.c
@@ -1916,6 +1916,51 @@ static void save_lscsa(struct spu_state *prev, struct spu *spu)
 	wait_spu_stopped(prev, spu);	/* Step 57. */
 }
 
+static void force_spu_isolate_exit(struct spu *spu)
+{
+	struct spu_problem __iomem *prob = spu->problem;
+	struct spu_priv2 __iomem *priv2 = spu->priv2;
+
+	/* Stop SPE execution and wait for completion. */
+	out_be32(&prob->spu_runcntl_RW, SPU_RUNCNTL_STOP);
+	iobarrier_rw();
+	POLL_WHILE_TRUE(in_be32(&prob->spu_status_R) & SPU_STATUS_RUNNING);
+
+	/* Restart SPE master runcntl. */
+	spu_mfc_sr1_set(spu, MFC_STATE1_MASTER_RUN_CONTROL_MASK);
+	iobarrier_w();
+
+	/* Initiate isolate exit request and wait for completion. */
+	out_be64(&priv2->spu_privcntl_RW, 4LL);
+	iobarrier_w();
+	out_be32(&prob->spu_runcntl_RW, 2);
+	iobarrier_rw();
+	POLL_WHILE_FALSE((in_be32(&prob->spu_status_R)
+				& SPU_STATUS_STOPPED_BY_STOP));
+
+	/* Reset load request to normal. */
+	out_be64(&priv2->spu_privcntl_RW, SPU_PRIVCNT_LOAD_REQUEST_NORMAL);
+	iobarrier_w();
+}
+
+/**
+ * stop_spu_isolate
+ *	Check SPU run-control state and force isolated
+ *	exit function as necessary.
+ */
+static void stop_spu_isolate(struct spu *spu)
+{
+	struct spu_problem __iomem *prob = spu->problem;
+
+	if (in_be32(&prob->spu_status_R) & SPU_STATUS_ISOLATED_STATE) {
+		/* The SPU is in isolated state; the only way
+		 * to get it out is to perform an isolated
+		 * exit (clean) operation.
+		 */
+		force_spu_isolate_exit(spu);
+	}
+}
+
 static void harvest(struct spu_state *prev, struct spu *spu)
 {
 	/*
@@ -1928,6 +1973,7 @@ static void harvest(struct spu_state *prev, struct spu *spu)
 	inhibit_user_access(prev, spu);	        /* Step 3.  */
 	terminate_spu_app(prev, spu);	        /* Step 4.  */
 	set_switch_pending(prev, spu);	        /* Step 5.  */
+	stop_spu_isolate(spu);			/* NEW.     */
 	remove_other_spu_access(prev, spu);	/* Step 6.  */
 	suspend_mfc(prev, spu);	                /* Step 7.  */
 	wait_suspend_mfc_complete(prev, spu);	/* Step 8.  */
@@ -2096,11 +2142,11 @@ int spu_save(struct spu_state *prev, struct spu *spu)
 	acquire_spu_lock(spu);	        /* Step 1.     */
 	rc = __do_spu_save(prev, spu);	/* Steps 2-53. */
 	release_spu_lock(spu);
-	if (rc) {
+	if (rc != 0 && rc != 2 && rc != 6) {
 		panic("%s failed on SPU[%d], rc=%d.\n",
 		      __func__, spu->number, rc);
 	}
-	return rc;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(spu_save);