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

From: Steven Rostedt
Date: Tue May 08 2018 - 17:07:47 EST


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.

> + __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

> );
>
> /*