Re: [PATCH v9 10/16] cxl/pci: Unify CXL trace logging for CXL Endpoints and CXL Ports

["Bowman, Terry" <terry.bowman@amd.com>]

On 6/6/2025 4:08 AM, Shiju Jose wrote:
>> -----Original Message-----
>> From: Terry Bowman <terry.bowman@amd.com>
>> Sent: 03 June 2025 18:23
>> To: PradeepVineshReddy.Kodamati@amd.com; dave@stgolabs.net; Jonathan
>> Cameron <jonathan.cameron@huawei.com>; dave.jiang@intel.com;
>> alison.schofield@intel.com; vishal.l.verma@intel.com; ira.weiny@intel.com;
>> dan.j.williams@intel.com; bhelgaas@google.com; bp@alien8.de;
>> ming.li@zohomail.com; Shiju Jose <shiju.jose@huawei.com>;
>> dan.carpenter@linaro.org; Smita.KoralahalliChannabasappa@amd.com;
>> kobayashi.da-06@fujitsu.com; terry.bowman@amd.com; yanfei.xu@intel.com;
>> rrichter@amd.com; peterz@infradead.org; colyli@suse.de;
>> uaisheng.ye@intel.com; fabio.m.de.francesco@linux.intel.com;
>> ilpo.jarvinen@linux.intel.com; yazen.ghannam@amd.com; linux-
>> cxl@vger.kernel.org; linux-kernel@vger.kernel.org; linux-pci@vger.kernel.org
>> Subject: [PATCH v9 10/16] cxl/pci: Unify CXL trace logging for CXL Endpoints and
>> CXL Ports
>>
>> CXL currently has separate trace routines for CXL Port errors and CXL Endpoint
>> errors. This is inconvenient for the user because they must enable
>> 2 sets of trace routines. Make updates to the trace logging such that a single
>> trace routine logs both CXL Endpoint and CXL Port protocol errors.
>>
>> Rename the 'host' field from the CXL Endpoint trace to 'parent' in the unified
>> trace routines. 'host' does not correctly apply to CXL Port devices. Parent is more
>> general and applies to CXL Port devices and CXL Endpoints.
>>
>> Add serial number parameter to the trace logging. This is used for EPs and 0 is
>> provided for CXL port devices without a serial number.
>>
>> Below is output of correctable and uncorrectable protocol error logging.
>> CXL Root Port and CXL Endpoint examples are included below.
>>
>> Root Port:
>> cxl_aer_correctable_error: device=0000:0c:00.0 parent=pci0000:0c serial: 0
>> status='CRC Threshold Hit'
>> cxl_aer_uncorrectable_error: device=0000:0c:00.0 parent=pci0000:0c serial: 0
>> status: 'Cache Byte Enable Parity Error' first_error: 'Cache Byte Enable Parity
>> Error'
>>
>> Endpoint:
>> cxl_aer_correctable_error: device=mem3 parent=0000:0f:00.0 serial=0
>> status='CRC Threshold Hit'
>> cxl_aer_uncorrectable_error: device=mem3 parent=0000:0f:00.0 serial: 0
>> status: 'Cache Byte Enable Parity Error' first_error: 'Cache Byte Enable Parity
>> Error'
>>
>> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
>> ---
>> drivers/cxl/core/pci.c   | 18 +++++----
>> drivers/cxl/core/ras.c   | 14 ++++---
>> drivers/cxl/core/trace.h | 84 +++++++++-------------------------------
>> 3 files changed, 37 insertions(+), 79 deletions(-)
>>
>> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index
>> 186a5a20b951..0f4c07fd64a5 100644
>> --- a/drivers/cxl/core/pci.c
>> +++ b/drivers/cxl/core/pci.c
>> @@ -664,7 +664,7 @@ void read_cdat_data(struct cxl_port *port)  }
>> EXPORT_SYMBOL_NS_GPL(read_cdat_data, "CXL");
>>
> [...]
>> static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data
>> *data) diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h index
>> 25ebfbc1616c..8c91b0f3d165 100644
>> --- a/drivers/cxl/core/trace.h
>> +++ b/drivers/cxl/core/trace.h
>> @@ -48,49 +48,22 @@
>> 	{ CXL_RAS_UC_IDE_RX_ERR, "IDE Rx Error" }			  \
>> )
>>
>> -TRACE_EVENT(cxl_port_aer_uncorrectable_error,
>> -	TP_PROTO(struct device *dev, u32 status, u32 fe, u32 *hl),
>> -	TP_ARGS(dev, status, fe, hl),
>> -	TP_STRUCT__entry(
>> -		__string(device, dev_name(dev))
>> -		__string(host, dev_name(dev->parent))
>> -		__field(u32, status)
>> -		__field(u32, first_error)
>> -		__array(u32, header_log, CXL_HEADERLOG_SIZE_U32)
>> -	),
>> -	TP_fast_assign(
>> -		__assign_str(device);
>> -		__assign_str(host);
>> -		__entry->status = status;
>> -		__entry->first_error = fe;
>> -		/*
>> -		 * Embed the 512B headerlog data for user app retrieval and
>> -		 * parsing, but no need to print this in the trace buffer.
>> -		 */
>> -		memcpy(__entry->header_log, hl, CXL_HEADERLOG_SIZE);
>> -	),
>> -	TP_printk("device=%s host=%s status: '%s' first_error: '%s'",
>> -		  __get_str(device), __get_str(host),
>> -		  show_uc_errs(__entry->status),
>> -		  show_uc_errs(__entry->first_error)
>> -	)
>> -);
>> -
>> TRACE_EVENT(cxl_aer_uncorrectable_error,
>> -	TP_PROTO(const struct cxl_memdev *cxlmd, u32 status, u32 fe, u32
>> *hl),
>> -	TP_ARGS(cxlmd, status, fe, hl),
>> +	TP_PROTO(struct device *dev, u64 serial, u32 status, u32 fe,
>> +		 u32 *hl),
>> +	TP_ARGS(dev, serial, status, fe, hl),
>> 	TP_STRUCT__entry(
>> -		__string(memdev, dev_name(&cxlmd->dev))
>> -		__string(host, dev_name(cxlmd->dev.parent))
>> +		__string(name, dev_name(dev))
>> +		__string(parent, dev_name(dev->parent))
> Hi Terry,
>
> As we pointed out in v8, renaming the fields "memdev" to "name" and "host" to "parent"
> causes issues and failures in userspace rasdaemon  while parsing the trace event data.
> Additionally, we can't rename these fields in rasdaemon  due to backward compatibility.
Yes, I remember but didn't understand why other SW couldn't be updated to handle. I will
change as you request but many people will be confused why a port device's name is labeled
as a memdev. memdev is only correct for EPs and does not correctly reflect *any* of the
other CXL device types (RP, USP, DSP).

>> 		__field(u64, serial)
>> 		__field(u32, status)
>> 		__field(u32, first_error)
>> 		__array(u32, header_log, CXL_HEADERLOG_SIZE_U32)
>> 	),
>> 	TP_fast_assign(
>> -		__assign_str(memdev);
>> -		__assign_str(host);
>> -		__entry->serial = cxlmd->cxlds->serial;
>> +		__assign_str(name);
>> +		__assign_str(parent);
>> +		__entry->serial = serial;
>> 		__entry->status = status;
>> 		__entry->first_error = fe;
>> 		/*
>> @@ -99,8 +72,8 @@ TRACE_EVENT(cxl_aer_uncorrectable_error,
>> 		 */
>> 		memcpy(__entry->header_log, hl, CXL_HEADERLOG_SIZE);
>> 	),
>> -	TP_printk("memdev=%s host=%s serial=%lld: status: '%s' first_error:
>> '%s'",
>> -		  __get_str(memdev), __get_str(host), __entry->serial,
>> +	TP_printk("device=%s parent=%s serial=%lld status='%s'
>> first_error='%s'",
>> +		  __get_str(name), __get_str(parent), __entry->serial,
>> 		  show_uc_errs(__entry->status),
>> 		  show_uc_errs(__entry->first_error)
>> 	)
>> @@ -124,42 +97,23 @@ TRACE_EVENT(cxl_aer_uncorrectable_error,
>> 	{ CXL_RAS_CE_PHYS_LAYER_ERR, "Received Error From Physical Layer"
>> }	\
>> )
>>
>> -TRACE_EVENT(cxl_port_aer_correctable_error,
>> -	TP_PROTO(struct device *dev, u32 status),
>> -	TP_ARGS(dev, status),
>> -	TP_STRUCT__entry(
>> -		__string(device, dev_name(dev))
>> -		__string(host, dev_name(dev->parent))
>> -		__field(u32, status)
>> -	),
>> -	TP_fast_assign(
>> -		__assign_str(device);
>> -		__assign_str(host);
>> -		__entry->status = status;
>> -	),
>> -	TP_printk("device=%s host=%s status='%s'",
>> -		  __get_str(device), __get_str(host),
>> -		  show_ce_errs(__entry->status)
>> -	)
>> -);
>> -
>> TRACE_EVENT(cxl_aer_correctable_error,
>> -	TP_PROTO(const struct cxl_memdev *cxlmd, u32 status),
>> -	TP_ARGS(cxlmd, status),
>> +	TP_PROTO(struct device *dev, u64 serial, u32 status),
>> +	TP_ARGS(dev, serial, status),
>> 	TP_STRUCT__entry(
>> -		__string(memdev, dev_name(&cxlmd->dev))
>> -		__string(host, dev_name(cxlmd->dev.parent))
>> +		__string(name, dev_name(dev))
>> +		__string(parent, dev_name(dev->parent))
> Renaming these fields is an issue for userspace as mentioned above 
> in cxl_aer_uncorrectable_error.
I understand, I'll revert as you request.

Terry
>> 		__field(u64, serial)
>> 		__field(u32, status)
>> 	),
>> 	TP_fast_assign(
>> -		__assign_str(memdev);
>> -		__assign_str(host);
>> -		__entry->serial = cxlmd->cxlds->serial;
>> +		__assign_str(name);
>> +		__assign_str(parent);
>> +		__entry->serial = serial;
>> 		__entry->status = status;
>> 	),
>> -	TP_printk("memdev=%s host=%s serial=%lld: status: '%s'",
>> -		  __get_str(memdev), __get_str(host), __entry->serial,
>> +	TP_printk("device=%s parent=%s serial=%lld status='%s'",
>> +		  __get_str(name), __get_str(parent), __entry->serial,
>> 		  show_ce_errs(__entry->status)
>> 	)
>> );
>> --
>> 2.34.1
>
> Thanks,
> Shiju