Re: [PATCH V2] PCI/AER: add pcie TLP header information in the tracepoint

[Thomas Tai <thomas.tai@xxxxxxxxxx>]

On 2018-05-08 05:07 PM, Steven Rostedt wrote:
> On Tue,  8 May 2018 15:57:00 -0400
> Thomas Tai <thomas.tai@xxxxxxxxxx> wrote:
>
> > When a PCIe AER occurs, the TLP header information is
> > printed in the kernel message but it is missing from
> > the tracepoint. A userspace program can use this information
> > in the tracepoint to better analyze problems.
> >
> > To enable the tracepoint:
> > echo 1 > /sys/kernel/debug/tracing/events/ras/aer_event/enable
> >
> > Example tracepoint output:
> > cat /sys/kernel/debug/tracing/trace
> > aer_event: 0000:01:00.0
> > PCIe Bus Error: severity=Uncorrected, non-fatal, Completer Abort
> > TLP Header={0x0,0x1,0x2,0x3}
> >
> > Signed-off-by: Thomas Tai <thomas.tai@xxxxxxxxxx>
> > ---
> >   drivers/pci/pcie/aer/aerdrv_errprint.c |  4 ++--
> >   include/ras/ras_event.h                | 22 ++++++++++++++++++----
> >   2 files changed, 20 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/pci/pcie/aer/aerdrv_errprint.c b/drivers/pci/pcie/aer/aerdrv_errprint.c
> > index cfc89dd..fd49a8d 100644
> > --- a/drivers/pci/pcie/aer/aerdrv_errprint.c
> > +++ b/drivers/pci/pcie/aer/aerdrv_errprint.c
> > @@ -189,7 +189,7 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
> >   		pci_err(dev, "  Error of this Agent(%04x) is reported first\n", id);
> >   
> >   	trace_aer_event(dev_name(&dev->dev), (info->status & ~info->mask),
> > -			info->severity);
> > +			info->severity, info->tlp_header_valid, &info->tlp);
> >   }
> >   
> >   void aer_print_port_info(struct pci_dev *dev, struct aer_err_info *info)
> > @@ -249,6 +249,6 @@ void cper_print_aer(struct pci_dev *dev, int aer_severity,
> >   		__print_tlp_header(dev, &aer->header_log);
> >   
> >   	trace_aer_event(dev_name(&dev->dev), (status & ~mask),
> > -			aer_severity);
> > +			aer_severity, tlp_header_valid, &aer->header_log);
> >   }
> >   #endif
> > diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
> > index 9c68986..f73b168 100644
> > --- a/include/ras/ras_event.h
> > +++ b/include/ras/ras_event.h
> > @@ -298,30 +298,44 @@
> >   TRACE_EVENT(aer_event,
> >   	TP_PROTO(const char *dev_name,
> >   		 const u32 status,
> > -		 const u8 severity),
> > +		 const u8 severity,
> > +		 const u8 tlp_header_valid,
> > +		 struct aer_header_log_regs *tlp),
> >   
> > -	TP_ARGS(dev_name, status, severity),
> > +	TP_ARGS(dev_name, status, severity, tlp_header_valid, tlp),
> >   
> >   	TP_STRUCT__entry(
> >   		__string(	dev_name,	dev_name	)
> >   		__field(	u32,		status		)
> >   		__field(	u8,		severity	)
> > +		__field(	u8, 		tlp_header_valid)
> > +		__array(	u32, 		tlp_header, 4	)
> >   	),
> >   
> >   	TP_fast_assign(
> >   		__assign_str(dev_name, dev_name);
> >   		__entry->status		= status;
> >   		__entry->severity	= severity;
> > +		__entry->tlp_header_valid = tlp_header_valid;
> > +		if (__entry->tlp_header_valid) {
>
> Although the compiler will probably optimize it anyway, but you
> probably should have it be:
>
> 		if (tlp_header_valid) {
>
> because why add the extra dereference.

Thanks Steven, good thinking. Will change and send v3.

Thomas



> > +			__entry->tlp_header[0] = tlp->dw0;
> > +			__entry->tlp_header[1] = tlp->dw1;
> > +			__entry->tlp_header[2] = tlp->dw2;
> > +			__entry->tlp_header[3] = tlp->dw3;
> > +		}
> >   	),
> >   
> > -	TP_printk("%s PCIe Bus Error: severity=%s, %s\n",
> > +	TP_printk("%s PCIe Bus Error: severity=%s, %s, TLP Header=%s\n",
> >   		__get_str(dev_name),
> >   		__entry->severity == AER_CORRECTABLE ? "Corrected" :
> >   			__entry->severity == AER_FATAL ?
> >   			"Fatal" : "Uncorrected, non-fatal",
> >   		__entry->severity == AER_CORRECTABLE ?
> >   		__print_flags(__entry->status, "|", aer_correctable_errors) :
> > -		__print_flags(__entry->status, "|", aer_uncorrectable_errors))
> > +		__print_flags(__entry->status, "|", aer_uncorrectable_errors),
> > +		__entry->tlp_header_valid ?
> > +			__print_array(__entry->tlp_header, 4, 4) :
> > +			"Not available")
>
> The rest looks fine to me.
>
> -- Steve
>
> >   );
> >   
> >   /*