On 2/9/23 4:34 AM, Jonathan Cameron wrote:
On Mon, 06 Feb 2023 13:49:48 -0700
Dave Jiang <dave.jiang@xxxxxxxxx> wrote:
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.
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Hi Dave,
Some comments on this follow on from previous patch so may not
be relevant once you've updated how that is done.
Dan advised to just drop the ACPICA changes and just do it locally since
the verification code is tiny and simple.
Jonathan
---
drivers/cxl/core/pci.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 57764e9cd19d..a24dac36bedd 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -3,6 +3,7 @@
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/device.h>
#include <linux/delay.h>
+#include <linux/acpi.h>
#include <linux/pci.h>
#include <linux/pci-doe.h>
#include <cxlpci.h>
@@ -592,6 +593,7 @@ void read_cdat_data(struct cxl_port *port)
struct device *dev = &port->dev;
struct device *uport = port->uport;
size_t cdat_length;
+ acpi_status status;
int rc;
cdat_doe = find_cdat_doe(uport);
@@ -620,5 +622,14 @@ void read_cdat_data(struct cxl_port *port)
port->cdat.length = 0;
dev_err(dev, "CDAT data read error\n");
}
+
+ status = acpi_ut_verify_cdat_checksum(port->cdat.table, port->cdat.length);
+ if (status != AE_OK) {
if (ACPI_FAILURE(acpi_ut...)) or better still put that in the wrapper I suggeste
in previous patch so that we have normal kernel return code handling out here.
+ /* Don't leave table data allocated on error */
+ devm_kfree(dev, port->cdat.table);
+ port->cdat.table = NULL;
+ port->cdat.length = 0;
I'd rather see us manipulate a local copy of cdat_length, and cdat_table
then only assign them to the port->cdat fields the success path rather
than setting them then unsetting the on error.
Diff will be bigger, but nicer resulting code (and hopefully diff
won't be too big!)
Ok, I'll create a prep patch to change this as you suggested.
+ dev_err(dev, "CDAT data checksum error\n");
+ }
}
EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
