PCI/AER: Add sysfs attributes for rootport cumulative stats

Add sysfs attributes for rootport statistics (that are cumulative of all
the ERR_* messages seen on this PCI hierarchy).

Signed-off-by: Rajat Jain <rajatja@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats

@@ -92,3 +92,31 @@ AtomicOp Egress Blocked 0
 TLP Prefix Blocked Error 0
 TOTAL_ERR_NONFATAL 0
 -------------------------------------------------------------------------
+
+============================
+PCIe Rootport AER statistics
+============================
+These attributes show up under only the rootports (or root complex event
+collectors) that are AER capable. These indicate the number of error messages as
+"reported to" the rootport. Please note that the rootports also transmit
+(internally) the ERR_* messages for errors seen by the internal rootport PCI
+device, so these counters include them and are thus cumulative of all the error
+messages on the PCI hierarchy originating at that root port.
+
+Where:		/sys/bus/pci/devices/<dev>/aer_stats/aer_rootport_total_err_cor
+Date:		July 2018
+Kernel Version: 4.19.0
+Contact:	linux-pci@vger.kernel.org, rajatja@google.com
+Description:	Total number of ERR_COR messages reported to rootport.
+
+Where:	    /sys/bus/pci/devices/<dev>/aer_stats/aer_rootport_total_err_fatal
+Date:		July 2018
+Kernel Version: 4.19.0
+Contact:	linux-pci@vger.kernel.org, rajatja@google.com
+Description:	Total number of ERR_FATAL messages reported to rootport.
+
+Where:	    /sys/bus/pci/devices/<dev>/aer_stats/aer_rootport_total_err_nonfatal
+Date:		July 2018
+Kernel Version: 4.19.0
+Contact:	linux-pci@vger.kernel.org, rajatja@google.com
+Description:	Total number of ERR_NONFATAL messages reported to rootport.

drivers/pci/pcie/aer.c

@@ -577,10 +577,30 @@ aer_stats_dev_attr(aer_dev_nonfatal, dev_nonfatal_errs,
 		   aer_uncorrectable_error_string, "ERR_NONFATAL",
 		   dev_total_nonfatal_errs);
 
+#define aer_stats_rootport_attr(name, field)				\
+	static ssize_t							\
+	name##_show(struct device *dev, struct device_attribute *attr,	\
+		     char *buf)						\
+{									\
+	struct pci_dev *pdev = to_pci_dev(dev);				\
+	return sprintf(buf, "%llu\n", pdev->aer_stats->field);		\
+}									\
+static DEVICE_ATTR_RO(name)
+
+aer_stats_rootport_attr(aer_rootport_total_err_cor,
+			 rootport_total_cor_errs);
+aer_stats_rootport_attr(aer_rootport_total_err_fatal,
+			 rootport_total_fatal_errs);
+aer_stats_rootport_attr(aer_rootport_total_err_nonfatal,
+			 rootport_total_nonfatal_errs);
+
 static struct attribute *aer_stats_attrs[] __ro_after_init = {
 	&dev_attr_aer_dev_correctable.attr,
 	&dev_attr_aer_dev_fatal.attr,
 	&dev_attr_aer_dev_nonfatal.attr,
+	&dev_attr_aer_rootport_total_err_cor.attr,
+	&dev_attr_aer_rootport_total_err_fatal.attr,
+	&dev_attr_aer_rootport_total_err_nonfatal.attr,
 	NULL
 };
 
@@ -593,6 +613,12 @@ static umode_t aer_stats_attrs_are_visible(struct kobject *kobj,
 	if (!pdev->aer_stats)
 		return 0;
 
+	if ((a == &dev_attr_aer_rootport_total_err_cor.attr ||
+	     a == &dev_attr_aer_rootport_total_err_fatal.attr ||
+	     a == &dev_attr_aer_rootport_total_err_nonfatal.attr) &&
+	    pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT)
+		return 0;
+
 	return a->mode;
 }
 
@@ -635,6 +661,25 @@ static void pci_dev_aer_stats_incr(struct pci_dev *pdev,
 			counter[i]++;
 }
 
+static void pci_rootport_aer_stats_incr(struct pci_dev *pdev,
+				 struct aer_err_source *e_src)
+{
+	struct aer_stats *aer_stats = pdev->aer_stats;
+
+	if (!aer_stats)
+		return;
+
+	if (e_src->status & PCI_ERR_ROOT_COR_RCV)
+		aer_stats->rootport_total_cor_errs++;
+
+	if (e_src->status & PCI_ERR_ROOT_UNCOR_RCV) {
+		if (e_src->status & PCI_ERR_ROOT_FATAL_RCV)
+			aer_stats->rootport_total_fatal_errs++;
+		else
+			aer_stats->rootport_total_nonfatal_errs++;
+	}
+}
+
 static void __print_tlp_header(struct pci_dev *dev,
 			       struct aer_header_log_regs *t)
 {
@@ -1085,6 +1130,8 @@ static void aer_isr_one_error(struct aer_rpc *rpc,
 	struct pci_dev *pdev = rpc->rpd;
 	struct aer_err_info *e_info = &rpc->e_info;
 
+	pci_rootport_aer_stats_incr(pdev, e_src);
+
 	/*
 	 * There is a possibility that both correctable error and
 	 * uncorrectable error being logged. Report correctable error first.