[v2,3/3] powerpc/pseries: fix bugs in mobility RTAS calls

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index e7cb6d4..37d16da 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -20,16 +20,11 @@ 
 
 #include <asm/machdep.h>
 #include <asm/rtas.h>
+
 #include "pseries.h"
 
-static struct kobject *mobility_kobj;
 
-struct update_props_workarea {
-	u32 phandle;
-	u32 state;
-	u64 reserved;
-	u32 nprops;
-} __packed;
+static struct kobject *mobility_kobj;
 
 #define NODE_ACTION_MASK	0xff000000
 #define NODE_COUNT_MASK		0x00ffffff
@@ -40,7 +35,7 @@  struct update_props_workarea {
 
 #define MIGRATION_SCOPE	(1)
 
-static int mobility_rtas_call(int token, char *buf, s32 scope)
+static int mobility_rtas_call(int token, void *buf, s32 scope)
 {
 	int rc;
 
@@ -54,171 +49,193 @@  static int mobility_rtas_call(int token, char *buf, s32 scope)
 	return rc;
 }
 
-static int delete_dt_node(u32 phandle)
+static int create_property(struct rtas_buffer *rtas_buf, struct property **prop,
+                           const char *name, int length)
 {
-	struct device_node *dn;
-
-	dn = of_find_node_by_phandle(phandle);
-	if (!dn)
-		return -ENOENT;
+	void *prop_value;
+	void *new_value;
 
-	dlpar_detach_node(dn);
-	of_node_put(dn);
-	return 0;
-}
+	struct property *working_prop = *prop;
 
-static int update_dt_property(struct device_node *dn, struct property **prop,
-			      const char *name, u32 vd, char *value)
-{
-	struct property *new_prop = *prop;
-	int more = 0;
+	if (!get_rtas_buf_mem(rtas_buf, &prop_value, length))
+		return -EOVERFLOW;
 
-	/* A negative 'vd' value indicates that only part of the new property
-	 * value is contained in the buffer and we need to call
-	 * ibm,update-properties again to get the rest of the value.
-	 *
-	 * A negative value is also the two's compliment of the actual value.
-	 */
-	if (vd & 0x80000000) {
-		vd = ~vd + 1;
-		more = 1;
-	}
-
-	if (new_prop) {
-		/* partial property fixup */
-		char *new_data = kzalloc(new_prop->length + vd, GFP_KERNEL);
-		if (!new_data)
-			return -ENOMEM;
-
-		memcpy(new_data, new_prop->value, new_prop->length);
-		memcpy(new_data + new_prop->length, value, vd);
-
-		kfree(new_prop->value);
-		new_prop->value = new_data;
-		new_prop->length += vd;
-	} else {
-		new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
-		if (!new_prop)
-			return -ENOMEM;
-
-		new_prop->name = kstrdup(name, GFP_KERNEL);
-		if (!new_prop->name) {
-			kfree(new_prop);
+	if (!working_prop) {
+		working_prop = kzalloc(sizeof(*working_prop), GFP_KERNEL);
+		if (!working_prop) {
 			return -ENOMEM;
 		}
 
-		new_prop->length = vd;
-		new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
-		if (!new_prop->value) {
-			kfree(new_prop->name);
-			kfree(new_prop);
+		working_prop->name = kstrdup(name, GFP_KERNEL | __GFP_NOWARN);
+		if (!working_prop->name) {
+			kfree(working_prop);
 			return -ENOMEM;
 		}
-
-		memcpy(new_prop->value, value, vd);
-		*prop = new_prop;
+		*prop = working_prop;
 	}
 
-	if (!more) {
-		of_update_property(dn, new_prop);
+	new_value = krealloc(working_prop->value, working_prop->length + length, GFP_KERNEL | __GFP_NOWARN);
+	if (!new_value) {
+		kfree(working_prop->value);
+		kfree(working_prop->name);
+		kfree(working_prop);
 		*prop = NULL;
+		return -ENOMEM;
 	}
 
+	working_prop->value = new_value;
+	memcpy(working_prop->value + working_prop->length, prop_value, length);
+	working_prop->length += length;
+
 	return 0;
 }
 
-static int update_dt_node(u32 phandle, s32 scope)
+static int parse_ibm_update_properties(struct rtas_buffer *rtas_buf, struct of_changeset *cs,
+                                       struct device_node *dn, struct property **r_prop)
 {
-	struct update_props_workarea *upwa;
-	struct device_node *dn;
+	int i;
+	int rc = 0;
+
 	struct property *prop = NULL;
-	int i, rc, rtas_rc;
-	char *prop_data;
-	char *rtas_buf;
-	int update_properties_token;
+
+	char peek;
+	u32 nprops;
 	u32 vd;
 
-	update_properties_token = rtas_token("ibm,update-properties");
-	if (update_properties_token == RTAS_UNKNOWN_SERVICE)
+	if (!rtas_buf || !cs || !dn || !r_prop)
 		return -EINVAL;
 
-	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
-	if (!rtas_buf)
-		return -ENOMEM;
+	/* Advance the buffer by 16 bytes which contain the phandle (4 bytes),
+	 * 4 bytes of state variable and 8 bytes of reserved (zero) bytes.
+	 * As the state variable must be sent on subsequent RTAS calls ensure
+	 * don't touch it so the caller can reuse this buffer.
+	 */
+	if (!advance_rtas_buf(rtas_buf, 16) || !get_rtas_buf_32(rtas_buf, &nprops))
+		return -EOVERFLOW;
 
-	dn = of_find_node_by_phandle(phandle);
-	if (!dn) {
-		kfree(rtas_buf);
-		return -ENOENT;
+	/* On the first call to ibm,update-properties for a node the
+	 * the first property value descriptor contains an empty
+	 * property name, the property value length encoded as u32,
+	 * and the property value is the node path being updated.
+	 *
+	 * Discard this information as the node was looked up by its phandle and
+	 * passed in.
+	 */
+	if (!peek_rtas_buf(rtas_buf, &peek))
+		return -EOVERFLOW;
+	if (peek == '\0') {
+		if (!advance_rtas_buf(rtas_buf, sizeof(u32)) ||
+		    !get_rtas_buf_32(rtas_buf, &vd) ||
+		    !advance_rtas_buf(rtas_buf, vd))
+			return -EOVERFLOW;
+		nprops--;
 	}
 
-	upwa = (struct update_props_workarea *)&rtas_buf[0];
-	upwa->phandle = phandle;
+	for (i = 0; i < nprops; i++) {
+		char *prop_name = NULL;
+		int prop_len;
 
-	do {
-		rtas_rc = mobility_rtas_call(update_properties_token, rtas_buf,
-					scope);
-		if (rtas_rc < 0)
+		if (!get_rtas_buf_str(rtas_buf, &prop_name) ||
+		    !get_rtas_buf_32(rtas_buf, &vd))
+				return -EOVERFLOW;
+
+		switch (vd) {
+		case 0x00000000:
+			/* name only property, nothing to do */
 			break;
 
-		prop_data = rtas_buf + sizeof(*upwa);
-
-		/* On the first call to ibm,update-properties for a node the
-		 * the first property value descriptor contains an empty
-		 * property name, the property value length encoded as u32,
-		 * and the property value is the node path being updated.
-		 */
-		if (*prop_data == 0) {
-			prop_data++;
-			vd = *(u32 *)prop_data;
-			prop_data += vd + sizeof(vd);
-			upwa->nprops--;
+		case 0x80000000:
+			prop = of_find_property(dn, prop_name, NULL);
+			of_changeset_remove_property(cs, dn, prop);
+			prop = NULL;
+			break;
+
+		default:
+			/* A negative 'vd' value indicates that only part of the new property
+			 * value is contained in the buffer and we need to call
+			 * ibm,update-properties again to get the rest of the value.
+			 *
+			 * A negative value is also the two's compliment of the actual value.
+			 */
+			prop_len = vd & 0x80000000 ? ~vd + 1 : vd;
+
+			rc = create_property(rtas_buf, &prop, prop_name, prop_len);
+			if (rc) {
+				printk(KERN_ERR "Could not update %s property\n", prop_name);
+				/* Could try to continue but failure in that function likely means
+				 * we have bigger problems.
+				 */
+				return rc;
+			}
+
+			if (prop && !(vd & 0x80000000)) {
+				of_changeset_update_property(cs, dn, prop);
+				prop = NULL;
+			}
 		}
+	}
 
-		for (i = 0; i < upwa->nprops; i++) {
-			char *prop_name;
+	if (prop)
+		*r_prop = prop;
+	return rc;
+}
 
-			prop_name = prop_data;
-			prop_data += strlen(prop_name) + 1;
-			vd = *(u32 *)prop_data;
-			prop_data += sizeof(vd);
+static int pseries_devicetree_update_props(struct of_changeset *cs, struct device_node *dn,
+                                           s32 scope)
+{
+	int rc;
+	int error;
+	int update_properties_token;
 
-			switch (vd) {
-			case 0x00000000:
-				/* name only property, nothing to do */
-				break;
+	void *buf;
+	struct rtas_buffer rtas_buf;
 
-			case 0x80000000:
-				prop = of_find_property(dn, prop_name, NULL);
-				of_remove_property(dn, prop);
-				prop = NULL;
-				break;
+	struct property *prop = NULL;
 
-			default:
-				rc = update_dt_property(dn, &prop, prop_name,
-							vd, prop_data);
-				if (rc) {
-					printk(KERN_ERR "Could not update %s"
-					       " property\n", prop_name);
-				}
+	if (!cs || !dn)
+		return -EINVAL;
 
-				prop_data += vd;
-			}
+	update_properties_token = rtas_token("ibm,update-properties");
+	if (update_properties_token == RTAS_UNKNOWN_SERVICE)
+		return -EINVAL;
+
+	rc = make_rtas_buf(&rtas_buf, RTAS_DATA_BUF_SIZE);
+	if (rc)
+		return -ENOMEM;
+
+	put_rtas_buf_32(&rtas_buf, dn->phandle, 0);
+
+	buf = get_rtas_buf(&rtas_buf);
+	if (!buf) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	do {
+
+		rc = mobility_rtas_call(update_properties_token, buf, scope);
+		if (rc < 0)
+			goto out;
+
+		error = parse_ibm_update_properties(&rtas_buf, cs, dn, &prop);
+		if (error) {
+			rc = error;
+			goto out;
 		}
-	} while (rtas_rc == 1);
 
-	of_node_put(dn);
-	kfree(rtas_buf);
-	return 0;
+	} while (rc == 1);
+
+out:
+	free_rtas_buf(&rtas_buf);
+	return rc;
 }
 
-static int add_dt_node(u32 parent_phandle, u32 drc_index)
+static int pseries_devicetree_update_node(struct of_changeset *cs, struct device_node *parent_dn,
+                                          u32 drc_index)
 {
 	struct device_node *dn;
-	struct device_node *parent_dn;
 	int rc;
 
-	parent_dn = of_find_node_by_phandle(parent_phandle);
 	if (!parent_dn)
 		return -ENOENT;
 
@@ -230,59 +247,122 @@  static int add_dt_node(u32 parent_phandle, u32 drc_index)
 	if (rc)
 		dlpar_free_cc_nodes(dn);
 
-	of_node_put(parent_dn);
 	return rc;
 }
 
+static int parse_ibm_update_nodes(struct rtas_buffer *rtas_buf, struct of_changeset *cs, s32 scope)
+{
+	u32 node;
+	int rc = 0;
+
+	if (!rtas_buf || !cs)
+		return -EINVAL;
+
+	/* Advance the buffer by 16 bytes which encompases 4 bytes of state
+	 * variable and 12 reserved (zeroed) bytes.
+	 * As the state variable must be sent on subsequent RTAS calls ensure
+	 * don't touch it so the caller can reuse this buffer.
+	 */
+	if (!advance_rtas_buf(rtas_buf, 16) ||
+	    !get_rtas_buf_32(rtas_buf, &node))
+		goto out;
+
+	while (node & NODE_ACTION_MASK) {
+		int i;
+		u32 action = node & NODE_ACTION_MASK;
+		int node_count = node & NODE_COUNT_MASK;
+		struct device_node *dn;
+
+		for (i = 0; i < node_count; i++) {
+			u32 phandle;
+			u32 drc_index;
+
+			if (!get_rtas_buf_32(rtas_buf, &phandle))
+				goto out;
+
+			dn = of_find_node_by_phandle(phandle);
+			if (!dn)
+				return -ENOENT;
+
+			switch (action) {
+			case DELETE_DT_NODE:
+				of_changeset_detach_node(cs, dn);
+				break;
+			case UPDATE_DT_NODE:
+				rc = pseries_devicetree_update_props(cs, dn, scope);
+				break;
+			case ADD_DT_NODE:
+				if (!get_rtas_buf_32(rtas_buf, &drc_index)) {
+					of_node_put(dn);
+					goto out;
+				}
+				rc = pseries_devicetree_update_node(cs, dn, drc_index);
+				break;
+			default:
+				of_node_put(dn);
+				/* Bogus action */
+				return -EINVAL; /* Break */
+			}
+			of_node_put(dn);
+		}
+		if (!get_rtas_buf_32(rtas_buf, &node))
+			goto out;
+	}
+
+	return rc;
+out:
+	printk(KERN_ERR "RTAS buffer length exceeded\n");
+	return -EOVERFLOW;
+}
+
 int pseries_devicetree_update(s32 scope)
 {
-	char *rtas_buf;
-	u32 *data;
+	struct rtas_buffer rtas_buf;
+	struct of_changeset cs;
+	void *buf;
 	int update_nodes_token;
 	int rc;
+	int error;
 
 	update_nodes_token = rtas_token("ibm,update-nodes");
 	if (update_nodes_token == RTAS_UNKNOWN_SERVICE)
 		return -EINVAL;
 
-	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
-	if (!rtas_buf)
-		return -ENOMEM;
+	of_changeset_init(&cs);
+
+	rc = make_rtas_buf(&rtas_buf, RTAS_DATA_BUF_SIZE);
+	if (rc) {
+		of_changeset_destroy(&cs);
+		return rc;
+	}
+
+	buf = get_rtas_buf(&rtas_buf);
+	if (!buf) {
+		rc = -ENOMEM;
+		goto out;
+	}
 
 	do {
-		rc = mobility_rtas_call(update_nodes_token, rtas_buf, scope);
+		rc = mobility_rtas_call(update_nodes_token, buf, scope);
 		if (rc && rc != 1)
 			break;
 
-		data = (u32 *)rtas_buf + 4;
-		while (*data & NODE_ACTION_MASK) {
-			int i;
-			u32 action = *data & NODE_ACTION_MASK;
-			int node_count = *data & NODE_COUNT_MASK;
-
-			data++;
-
-			for (i = 0; i < node_count; i++) {
-				u32 phandle = *data++;
-				u32 drc_index;
-
-				switch (action) {
-				case DELETE_DT_NODE:
-					delete_dt_node(phandle);
-					break;
-				case UPDATE_DT_NODE:
-					update_dt_node(phandle, scope);
-					break;
-				case ADD_DT_NODE:
-					drc_index = *data++;
-					add_dt_node(phandle, drc_index);
-					break;
-				}
-			}
-		}
+		error = parse_ibm_update_nodes(&rtas_buf, &cs, scope);
+		if (error)
+			break;
+
 	} while (rc == 1);
 
-	kfree(rtas_buf);
+	if (error)
+		rc = error;
+
+	if (rc == 0)
+		rc = of_changeset_apply_locked(&cs);
+
+out:
+	of_changeset_destroy(&cs);
+	free_rtas_buf(&rtas_buf);
+
 	return rc;
 }