diff mbox series

[3,02/23] cxl: Add checksum verification to CDAT from CXL

Message ID 168088752692.1441063.12748870422089681966.stgit@djiang5-mobl3
State Superseded
Headers show
Series cxl: Add support for QTG ID retrieval for CXL subsystem | expand

Commit Message

Dave Jiang April 7, 2023, 5:12 p.m. UTC 
A CDAT table is available from a CXL device. The table is read by the
driver and cached in software. With the CXL subsystem needing to parse the
CDAT table, the checksum should be verified. Add checksum verification
after the CDAT table is read from device.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

---
v3:
- Just return the final sum. (Alison)
v2:
- Drop ACPI checksum export and just use local verification. (Dan)
---
 drivers/cxl/core/pci.c |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)
diff mbox series

Patch

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 25b7e8125d5d..9c7e2f69d9ca 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -528,6 +528,16 @@  static int cxl_cdat_read_table(struct device *dev,
 	return 0;
 }
 
+static unsigned char cdat_checksum(void *buf, size_t size)
+{
+	unsigned char sum, *data = buf;
+	size_t i;
+
+	for (sum = 0, i = 0; i < size; i++)
+		sum += data[i];
+	return sum;
+}
+
 /**
  * read_cdat_data - Read the CDAT data on this port
  * @port: Port to read data from
@@ -573,6 +583,12 @@  void read_cdat_data(struct cxl_port *port)
 	}
 
 	port->cdat.table = cdat_table + sizeof(__le32);
+	if (cdat_checksum(port->cdat.table, cdat_length)) {
+		/* Don't leave table data allocated on error */
+		devm_kfree(dev, cdat_table);
+		dev_err(dev, "CDAT data checksum error\n");
+	}
+
 	port->cdat.length = cdat_length;
 }
 EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);