Messages in this thread | | | Date | Tue, 28 Jun 2022 15:49:42 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH V12 7/9] cxl/port: Introduce cxl_cdat_valid() |
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On Mon, 27 Jun 2022 21:15:25 -0700 ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com> > > The CDAT data is protected by a checksum and should be the proper > length. > > Introduce cxl_cdat_valid() to validate the data. While at it check and > store the sequence number. > > Signed-off-by: Ira Weiny <ira.weiny@intel.com> > Minor ordering comment. With that tidied up Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c > index 4bd479ec0253..6d775cc3dca1 100644 > --- a/drivers/cxl/core/pci.c > +++ b/drivers/cxl/core/pci.c > @@ -532,6 +532,40 @@ static int cxl_cdat_get_length(struct device *dev, > return rc; > } > > +static bool cxl_cdat_valid(struct device *dev, struct cxl_cdat *cdat) > +{ > + u32 *table = cdat->table; > + u8 *data8 = cdat->table; > + u32 length, seq; > + u8 check; > + int i; > + > + length = FIELD_GET(CDAT_HEADER_DW0_LENGTH, table[0]); > + if ((length < CDAT_HEADER_LENGTH_BYTES) || (length > cdat->length)) { > + dev_err(dev, "CDAT Invalid length %u (%zu-%zu)\n", length, > + CDAT_HEADER_LENGTH_BYTES, cdat->length); > + return false; > + } > + > + for (check = 0, i = 0; i < length; i++) > + check += data8[i]; > + > + dev_dbg(dev, "CDAT length %u CS %u\n", length, check); > + if (check != 0) { > + dev_err(dev, "CDAT Invalid checksum %u\n", check); > + return false; > + } > + > + seq = FIELD_GET(CDAT_HEADER_DW3_SEQUENCE, table[3]); > + /* Store the sequence for now. */ > + if (cdat->seq != seq) { > + dev_info(dev, "CDAT seq change %x -> %x\n", cdat->seq, seq); > + cdat->seq = seq; > + } > + > + return true; > +} > + > static int cxl_cdat_read_table(struct device *dev, > struct pci_doe_mb *cdat_mb, > struct cxl_cdat *cdat) > @@ -579,6 +613,8 @@ static int cxl_cdat_read_table(struct device *dev, > > } while (entry_handle != CXL_DOE_TABLE_ACCESS_LAST_ENTRY); > > + if (!rc && !cxl_cdat_valid(dev, cdat)) > + return -EIO;
I'd prefer those handled separately as flow is more readable if error handling always out of line.
if (rc) return rc;
if (!cxl_cdata_valid) return -EIO;
return 0;
> return rc; > } >
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