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SubjectRe: [RFC PATCH] coresight: dynamic-replicator: Fix handling of multiple connections
Hi Suzuki,

On 2020-04-09 04:13, Suzuki K Poulose wrote:
> On Tue, Apr 07, 2020 at 08:48:54PM +0530, Sai Prakash Ranjan wrote:
>
> Please find the untested patch below.
>
> ---8>---
>
> [untested] coresight: Fix support for sparse port numbers
>
> On some systems the firmware may not describe all the ports
> connected to a component (e.g, for security reasons). This
> could be especially problematic for "funnels" where we could
> end up in modifying memory beyond the allocated space for
> refcounts.
>
> e.g, for a funnel with input ports listed 0, 3, 5, nr_inport = 3.
> However the we could access refcnts[5] while checking for
> references.
>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> .../hwtracing/coresight/coresight-platform.c | 74 ++++++++++++-------
> drivers/hwtracing/coresight/coresight.c | 8 +-
> 2 files changed, 56 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c
> b/drivers/hwtracing/coresight/coresight-platform.c
> index 3c5bee429105..1c610d6e944b 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -67,6 +67,7 @@ static void of_coresight_get_ports_legacy(const
> struct device_node *node,
> int *nr_inport, int *nr_outport)
> {
> struct device_node *ep = NULL;
> + struct of_endpoint endpoint;
> int in = 0, out = 0;
>
> do {
> @@ -74,10 +75,16 @@ static void of_coresight_get_ports_legacy(const
> struct device_node *node,
> if (!ep)
> break;
>
> - if (of_coresight_legacy_ep_is_input(ep))
> - in++;
> - else
> - out++;
> + if (of_graph_parse_endpoint(ep, &endpoint))
> + continue;
> +
> + if (of_coresight_legacy_ep_is_input(ep)) {
> + in = (endpoint.port + 1 > in) ?
> + endpoint.port + 1 : in;
> + } else {
> + out = (endpoint.port + 1) > out ?
> + endpoint.port + 1 : out;
> + }
>
> } while (ep);
>
> @@ -117,9 +124,16 @@ of_coresight_count_ports(struct device_node
> *port_parent)
> {
> int i = 0;
> struct device_node *ep = NULL;
> + struct of_endpoint endpoint;
> +
> + while ((ep = of_graph_get_next_endpoint(port_parent, ep))) {
> + /* Defer error handling to parsing */
> + if (of_graph_parse_endpoint(ep, &endpoint))
> + continue;
> + if (endpoint.port + 1 > i)
> + i = endpoint.port + 1;
> + }
>
> - while ((ep = of_graph_get_next_endpoint(port_parent, ep)))
> - i++;
> return i;
> }
>
> @@ -171,14 +185,12 @@ static int of_coresight_get_cpu(struct device
> *dev)
> * Parses the local port, remote device name and the remote port.
> *
> * Returns :
> - * 1 - If the parsing is successful and a connection record
> - * was created for an output connection.
> * 0 - If the parsing completed without any fatal errors.
> * -Errno - Fatal error, abort the scanning.
> */
> static int of_coresight_parse_endpoint(struct device *dev,
> struct device_node *ep,
> - struct coresight_connection *conn)
> + struct coresight_platform_data *pdata)
> {
> int ret = 0;
> struct of_endpoint endpoint, rendpoint;
> @@ -186,6 +198,7 @@ static int of_coresight_parse_endpoint(struct
> device *dev,
> struct device_node *rep = NULL;
> struct device *rdev = NULL;
> struct fwnode_handle *rdev_fwnode;
> + struct coresight_connection *conn;
>
> do {
> /* Parse the local port details */
> @@ -212,6 +225,12 @@ static int of_coresight_parse_endpoint(struct
> device *dev,
> break;
> }
>
> + conn = &pdata->conns[endpoint.port];
> + if (conn->child_fwnode) {
> + dev_warn(dev, "Duplicate output port %d\n", endpoint.port);
> + ret = -EINVAL;
> + break;
> + }
> conn->outport = endpoint.port;
> /*
> * Hold the refcount to the target device. This could be
> @@ -224,7 +243,6 @@ static int of_coresight_parse_endpoint(struct
> device *dev,
> conn->child_fwnode = fwnode_handle_get(rdev_fwnode);
> conn->child_port = rendpoint.port;
> /* Connection record updated */
> - ret = 1;
> } while (0);
>
> of_node_put(rparent);
> @@ -238,7 +256,6 @@ static int of_get_coresight_platform_data(struct
> device *dev,
> struct coresight_platform_data *pdata)
> {
> int ret = 0;
> - struct coresight_connection *conn;
> struct device_node *ep = NULL;
> const struct device_node *parent = NULL;
> bool legacy_binding = false;
> @@ -267,8 +284,6 @@ static int of_get_coresight_platform_data(struct
> device *dev,
> dev_warn_once(dev, "Uses obsolete Coresight DT bindings\n");
> }
>
> - conn = pdata->conns;
> -
> /* Iterate through each output port to discover topology */
> while ((ep = of_graph_get_next_endpoint(parent, ep))) {
> /*
> @@ -280,15 +295,9 @@ static int of_get_coresight_platform_data(struct
> device *dev,
> if (legacy_binding && of_coresight_legacy_ep_is_input(ep))
> continue;
>
> - ret = of_coresight_parse_endpoint(dev, ep, conn);
> - switch (ret) {
> - case 1:
> - conn++; /* Fall through */
> - case 0:
> - break;
> - default:
> + ret = of_coresight_parse_endpoint(dev, ep, pdata);
> + if (ret)
> return ret;
> - }
> }
>
> return 0;
> @@ -627,6 +636,11 @@ static int acpi_coresight_parse_link(struct
> acpi_device *adev,
> * coresight_remove_match().
> */
> conn->child_fwnode = fwnode_handle_get(&r_adev->fwnode);
> + } else if (dir == ACPI_CORESIGHT_LINK_SLAVE) {
> + conn->child_port = fields[0].integer.value;
> + } else {
> + /* Invalid direction */
> + return -EINVAL;
> }
>
> return dir;
> @@ -672,10 +686,14 @@ static int acpi_coresight_parse_graph(struct
> acpi_device *adev,
> return dir;
>
> if (dir == ACPI_CORESIGHT_LINK_MASTER) {
> - pdata->nr_outport++;
> + if (ptr->outport > pdata->nr_outport)
> + pdata->nr_outport = ptr->outport;
> ptr++;
> } else {
> - pdata->nr_inport++;
> + WARN_ON(pdata->nr_inport == ptr->child_port);
> + /* Do not move the ptr for input connections */
> + if (ptr->child_port > pdata->nr_inport)
> + pdata->nr_inport = ptr->child_port;
> }
> }
>
> @@ -684,8 +702,13 @@ static int acpi_coresight_parse_graph(struct
> acpi_device *adev,
> return rc;
>
> /* Copy the connection information to the final location */
> - for (i = 0; i < pdata->nr_outport; i++)
> - pdata->conns[i] = conns[i];
> + for (i = 0; conns + i < ptr; i++) {
> + int port = conns[i].outport;
> +
> + /* Duplicate output port */
> + WARN_ON(pdata->conns[port].child_fwnode);
> + pdata->conns[port] = conns[i];
> + }
>
> devm_kfree(&adev->dev, conns);
> return 0;
> @@ -787,6 +810,7 @@ coresight_get_platform_data(struct device *dev)
> goto error;
>
> pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> + pdata->nr_outport = pdata->nr_inport = -1;
> if (!pdata) {
> ret = -ENOMEM;
> goto error;
> diff --git a/drivers/hwtracing/coresight/coresight.c
> b/drivers/hwtracing/coresight/coresight.c
> index ef20f74c85fa..f07bc0a7ab88 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -990,6 +990,9 @@ static int coresight_orphan_match(struct device
> *dev, void *data)
> for (i = 0; i < i_csdev->pdata->nr_outport; i++) {
> conn = &i_csdev->pdata->conns[i];
>
> + /* Skip the port if FW doesn't describe it */
> + if (!conn->child_fwnode)
> + continue;
> /* We have found at least one orphan connection */
> if (conn->child_dev == NULL) {
> /* Does it match this newly added device? */
> @@ -1029,6 +1032,9 @@ static void coresight_fixup_device_conns(struct
> coresight_device *csdev)
> struct coresight_connection *conn = &csdev->pdata->conns[i];
> struct device *dev = NULL;
>
> + if (!conn->child_fwnode)
> + continue;
> +
> dev = bus_find_device_by_fwnode(&coresight_bustype,
> conn->child_fwnode);
> if (dev) {
> conn->child_dev = to_coresight_device(dev);
> @@ -1061,7 +1067,7 @@ static int coresight_remove_match(struct device
> *dev, void *data)
> for (i = 0; i < iterator->pdata->nr_outport; i++) {
> conn = &iterator->pdata->conns[i];
>
> - if (conn->child_dev == NULL)
> + if (conn->child_dev == NULL || conn->child_fwnode == NULL)
> continue;
>
> if (csdev->dev.fwnode == conn->child_fwnode) {


Thanks Suzuki, I don't see the KASAN warning anymore with this patch.
But somehow tmc_etr probe fails with error -12(ENOMEM).

Thanks,
Sai

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