PCI/AER: Add sysfs attributes for log ratelimits
authorJon Pan-Doh <pandoh@google.com>
Thu, 22 May 2025 23:21:26 +0000 (18:21 -0500)
committerBjorn Helgaas <bhelgaas@google.com>
Fri, 23 May 2025 16:11:45 +0000 (11:11 -0500)
Allow userspace to read/write log ratelimits per device (including
enable/disable). Create aer/ sysfs directory to store them and any
future AER configs.

The new sysfs files are:

  /sys/bus/pci/devices/*/aer/correctable_ratelimit_burst
  /sys/bus/pci/devices/*/aer/correctable_ratelimit_interval_ms
  /sys/bus/pci/devices/*/aer/nonfatal_ratelimit_burst
  /sys/bus/pci/devices/*/aer/nonfatal_ratelimit_interval_ms

The default values are ratelimit_burst=10, ratelimit_interval_ms=5000, so
if we try to emit more than 10 messages in a 5 second period, some are
suppressed.

Update AER sysfs ABI filename to reflect the broader scope of AER sysfs
attributes (e.g. stats and ratelimits).

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

Tested using aer-inject[1]. Configured correctable log ratelimit to 5.
Sent 6 AER errors. Observed 5 errors logged while AER stats
(cat /sys/bus/pci/devices/<dev>/aer_dev_correctable) shows 6.

Disabled ratelimiting and sent 6 more AER errors. Observed all 6 errors
logged and accounted in AER stats (12 total errors).

[1] https://git.kernel.org/pub/scm/linux/kernel/git/gong.chen/aer-inject.git

[bhelgaas: note fatal errors are not ratelimited, "aer_report" ->
"aer_info", replace ratelimit_log_enable toggle with *_ratelimit_interval_ms]

Signed-off-by: Karolina Stolarek <karolina.stolarek@oracle.com>
Signed-off-by: Jon Pan-Doh <pandoh@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://patch.msgid.link/20250522232339.1525671-21-helgaas@kernel.org
Documentation/ABI/testing/sysfs-bus-pci-devices-aer [new file with mode: 0644]
Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats [deleted file]
Documentation/PCI/pcieaer-howto.rst
drivers/pci/pci-sysfs.c
drivers/pci/pci.h
drivers/pci/pcie/aer.c

diff --git a/Documentation/ABI/testing/sysfs-bus-pci-devices-aer b/Documentation/ABI/testing/sysfs-bus-pci-devices-aer
new file mode 100644 (file)
index 0000000..5ed2845
--- /dev/null
@@ -0,0 +1,163 @@
+PCIe Device AER statistics
+--------------------------
+
+These attributes show up under all the devices that are AER capable. These
+statistical counters indicate the errors "as seen/reported by the device".
+Note that this may mean that if an endpoint is causing problems, the AER
+counters may increment at its link partner (e.g. root port) because the
+errors may be "seen" / reported by the link partner and not the
+problematic endpoint itself (which may report all counters as 0 as it never
+saw any problems).
+
+What:          /sys/bus/pci/devices/<dev>/aer_dev_correctable
+Date:          July 2018
+KernelVersion: 4.19.0
+Contact:       linux-pci@vger.kernel.org, rajatja@google.com
+Description:   List of correctable errors seen and reported by this
+               PCI device using ERR_COR. Note that since multiple errors may
+               be reported using a single ERR_COR message, thus
+               TOTAL_ERR_COR at the end of the file may not match the actual
+               total of all the errors in the file. Sample output::
+
+                   localhost /sys/devices/pci0000:00/0000:00:1c.0 # cat aer_dev_correctable
+                   Receiver Error 2
+                   Bad TLP 0
+                   Bad DLLP 0
+                   RELAY_NUM Rollover 0
+                   Replay Timer Timeout 0
+                   Advisory Non-Fatal 0
+                   Corrected Internal Error 0
+                   Header Log Overflow 0
+                   TOTAL_ERR_COR 2
+
+What:          /sys/bus/pci/devices/<dev>/aer_dev_fatal
+Date:          July 2018
+KernelVersion: 4.19.0
+Contact:       linux-pci@vger.kernel.org, rajatja@google.com
+Description:   List of uncorrectable fatal errors seen and reported by this
+               PCI device using ERR_FATAL. Note that since multiple errors may
+               be reported using a single ERR_FATAL message, thus
+               TOTAL_ERR_FATAL at the end of the file may not match the actual
+               total of all the errors in the file. Sample output::
+
+                   localhost /sys/devices/pci0000:00/0000:00:1c.0 # cat aer_dev_fatal
+                   Undefined 0
+                   Data Link Protocol 0
+                   Surprise Down Error 0
+                   Poisoned TLP 0
+                   Flow Control Protocol 0
+                   Completion Timeout 0
+                   Completer Abort 0
+                   Unexpected Completion 0
+                   Receiver Overflow 0
+                   Malformed TLP 0
+                   ECRC 0
+                   Unsupported Request 0
+                   ACS Violation 0
+                   Uncorrectable Internal Error 0
+                   MC Blocked TLP 0
+                   AtomicOp Egress Blocked 0
+                   TLP Prefix Blocked Error 0
+                   TOTAL_ERR_FATAL 0
+
+What:          /sys/bus/pci/devices/<dev>/aer_dev_nonfatal
+Date:          July 2018
+KernelVersion: 4.19.0
+Contact:       linux-pci@vger.kernel.org, rajatja@google.com
+Description:   List of uncorrectable nonfatal errors seen and reported by this
+               PCI device using ERR_NONFATAL. Note that since multiple errors
+               may be reported using a single ERR_FATAL message, thus
+               TOTAL_ERR_NONFATAL at the end of the file may not match the
+               actual total of all the errors in the file. Sample output::
+
+                   localhost /sys/devices/pci0000:00/0000:00:1c.0 # cat aer_dev_nonfatal
+                   Undefined 0
+                   Data Link Protocol 0
+                   Surprise Down Error 0
+                   Poisoned TLP 0
+                   Flow Control Protocol 0
+                   Completion Timeout 0
+                   Completer Abort 0
+                   Unexpected Completion 0
+                   Receiver Overflow 0
+                   Malformed TLP 0
+                   ECRC 0
+                   Unsupported Request 0
+                   ACS Violation 0
+                   Uncorrectable Internal Error 0
+                   MC Blocked TLP 0
+                   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.
+
+What:          /sys/bus/pci/devices/<dev>/aer_rootport_total_err_cor
+Date:          July 2018
+KernelVersion: 4.19.0
+Contact:       linux-pci@vger.kernel.org, rajatja@google.com
+Description:   Total number of ERR_COR messages reported to rootport.
+
+What:          /sys/bus/pci/devices/<dev>/aer_rootport_total_err_fatal
+Date:          July 2018
+KernelVersion: 4.19.0
+Contact:       linux-pci@vger.kernel.org, rajatja@google.com
+Description:   Total number of ERR_FATAL messages reported to rootport.
+
+What:          /sys/bus/pci/devices/<dev>/aer_rootport_total_err_nonfatal
+Date:          July 2018
+KernelVersion: 4.19.0
+Contact:       linux-pci@vger.kernel.org, rajatja@google.com
+Description:   Total number of ERR_NONFATAL messages reported to rootport.
+
+PCIe AER ratelimits
+-------------------
+
+These attributes show up under all the devices that are AER capable.
+They represent configurable ratelimits of logs per error type.
+
+See Documentation/PCI/pcieaer-howto.rst for more info on ratelimits.
+
+What:          /sys/bus/pci/devices/<dev>/aer/correctable_ratelimit_interval_ms
+Date:          May 2025
+KernelVersion: 6.16.0
+Contact:       linux-pci@vger.kernel.org
+Description:   Writing 0 disables AER correctable error log ratelimiting.
+               Writing a positive value sets the ratelimit interval in ms.
+               Default is DEFAULT_RATELIMIT_INTERVAL (5000 ms).
+
+What:          /sys/bus/pci/devices/<dev>/aer/correctable_ratelimit_burst
+Date:          May 2025
+KernelVersion: 6.16.0
+Contact:       linux-pci@vger.kernel.org
+Description:   Ratelimit burst for correctable error logs. Writing a value
+               changes the number of errors (burst) allowed per interval
+               before ratelimiting. Reading gets the current ratelimit
+               burst. Default is DEFAULT_RATELIMIT_BURST (10).
+
+What:          /sys/bus/pci/devices/<dev>/aer/nonfatal_ratelimit_interval_ms
+Date:          May 2025
+KernelVersion: 6.16.0
+Contact:       linux-pci@vger.kernel.org
+Description:   Writing 0 disables AER non-fatal uncorrectable error log
+               ratelimiting. Writing a positive value sets the ratelimit
+               interval in ms. Default is DEFAULT_RATELIMIT_INTERVAL
+               (5000 ms).
+
+What:          /sys/bus/pci/devices/<dev>/aer/nonfatal_ratelimit_burst
+Date:          May 2025
+KernelVersion: 6.16.0
+Contact:       linux-pci@vger.kernel.org
+Description:   Ratelimit burst for non-fatal uncorrectable error logs.
+               Writing a value changes the number of errors (burst)
+               allowed per interval before ratelimiting. Reading gets the
+               current ratelimit burst. Default is DEFAULT_RATELIMIT_BURST
+               (10).
diff --git a/Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats b/Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats
deleted file mode 100644 (file)
index d1f67bb..0000000
+++ /dev/null
@@ -1,119 +0,0 @@
-PCIe Device AER statistics
---------------------------
-
-These attributes show up under all the devices that are AER capable. These
-statistical counters indicate the errors "as seen/reported by the device".
-Note that this may mean that if an endpoint is causing problems, the AER
-counters may increment at its link partner (e.g. root port) because the
-errors may be "seen" / reported by the link partner and not the
-problematic endpoint itself (which may report all counters as 0 as it never
-saw any problems).
-
-What:          /sys/bus/pci/devices/<dev>/aer_dev_correctable
-Date:          July 2018
-KernelVersion: 4.19.0
-Contact:       linux-pci@vger.kernel.org, rajatja@google.com
-Description:   List of correctable errors seen and reported by this
-               PCI device using ERR_COR. Note that since multiple errors may
-               be reported using a single ERR_COR message, thus
-               TOTAL_ERR_COR at the end of the file may not match the actual
-               total of all the errors in the file. Sample output::
-
-                   localhost /sys/devices/pci0000:00/0000:00:1c.0 # cat aer_dev_correctable
-                   Receiver Error 2
-                   Bad TLP 0
-                   Bad DLLP 0
-                   RELAY_NUM Rollover 0
-                   Replay Timer Timeout 0
-                   Advisory Non-Fatal 0
-                   Corrected Internal Error 0
-                   Header Log Overflow 0
-                   TOTAL_ERR_COR 2
-
-What:          /sys/bus/pci/devices/<dev>/aer_dev_fatal
-Date:          July 2018
-KernelVersion: 4.19.0
-Contact:       linux-pci@vger.kernel.org, rajatja@google.com
-Description:   List of uncorrectable fatal errors seen and reported by this
-               PCI device using ERR_FATAL. Note that since multiple errors may
-               be reported using a single ERR_FATAL message, thus
-               TOTAL_ERR_FATAL at the end of the file may not match the actual
-               total of all the errors in the file. Sample output::
-
-                   localhost /sys/devices/pci0000:00/0000:00:1c.0 # cat aer_dev_fatal
-                   Undefined 0
-                   Data Link Protocol 0
-                   Surprise Down Error 0
-                   Poisoned TLP 0
-                   Flow Control Protocol 0
-                   Completion Timeout 0
-                   Completer Abort 0
-                   Unexpected Completion 0
-                   Receiver Overflow 0
-                   Malformed TLP 0
-                   ECRC 0
-                   Unsupported Request 0
-                   ACS Violation 0
-                   Uncorrectable Internal Error 0
-                   MC Blocked TLP 0
-                   AtomicOp Egress Blocked 0
-                   TLP Prefix Blocked Error 0
-                   TOTAL_ERR_FATAL 0
-
-What:          /sys/bus/pci/devices/<dev>/aer_dev_nonfatal
-Date:          July 2018
-KernelVersion: 4.19.0
-Contact:       linux-pci@vger.kernel.org, rajatja@google.com
-Description:   List of uncorrectable nonfatal errors seen and reported by this
-               PCI device using ERR_NONFATAL. Note that since multiple errors
-               may be reported using a single ERR_FATAL message, thus
-               TOTAL_ERR_NONFATAL at the end of the file may not match the
-               actual total of all the errors in the file. Sample output::
-
-                   localhost /sys/devices/pci0000:00/0000:00:1c.0 # cat aer_dev_nonfatal
-                   Undefined 0
-                   Data Link Protocol 0
-                   Surprise Down Error 0
-                   Poisoned TLP 0
-                   Flow Control Protocol 0
-                   Completion Timeout 0
-                   Completer Abort 0
-                   Unexpected Completion 0
-                   Receiver Overflow 0
-                   Malformed TLP 0
-                   ECRC 0
-                   Unsupported Request 0
-                   ACS Violation 0
-                   Uncorrectable Internal Error 0
-                   MC Blocked TLP 0
-                   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.
-
-What:          /sys/bus/pci/devices/<dev>/aer_rootport_total_err_cor
-Date:          July 2018
-KernelVersion: 4.19.0
-Contact:       linux-pci@vger.kernel.org, rajatja@google.com
-Description:   Total number of ERR_COR messages reported to rootport.
-
-What:          /sys/bus/pci/devices/<dev>/aer_rootport_total_err_fatal
-Date:          July 2018
-KernelVersion: 4.19.0
-Contact:       linux-pci@vger.kernel.org, rajatja@google.com
-Description:   Total number of ERR_FATAL messages reported to rootport.
-
-What:          /sys/bus/pci/devices/<dev>/aer_rootport_total_err_nonfatal
-Date:          July 2018
-KernelVersion: 4.19.0
-Contact:       linux-pci@vger.kernel.org, rajatja@google.com
-Description:   Total number of ERR_NONFATAL messages reported to rootport.
index 6fb31516fff1cc0628d220f47272aea9ca9bb3d8..4b71e2f43ca7ed9c710ef7d36fa11c08d7fb3b44 100644 (file)
@@ -97,12 +97,15 @@ DPC errors, are not ratelimited.
 AER uses the default ratelimit of DEFAULT_RATELIMIT_BURST (10 events) over
 DEFAULT_RATELIMIT_INTERVAL (5 seconds).
 
+Ratelimits are exposed in the form of sysfs attributes and configurable.
+See Documentation/ABI/testing/sysfs-bus-pci-devices-aer.
+
 AER Statistics / Counters
 -------------------------
 
 When PCIe AER errors are captured, the counters / statistics are also exposed
 in the form of sysfs attributes which are documented at
-Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats
+Documentation/ABI/testing/sysfs-bus-pci-devices-aer.
 
 Developer Guide
 ===============
index c6cda56ca52ccf1a15e4e48cebdc176def143ab1..278de99b00ce751d6af4232ef018f6585846601b 100644 (file)
@@ -1805,6 +1805,7 @@ const struct attribute_group *pci_dev_attr_groups[] = {
        &pcie_dev_attr_group,
 #ifdef CONFIG_PCIEAER
        &aer_stats_attr_group,
+       &aer_attr_group,
 #endif
 #ifdef CONFIG_PCIEASPM
        &aspm_ctrl_attr_group,
index 3023c68fe485a5a63b30b09ba2a3d87af3fafe86..eca2812cfd25e7443f887b1abde71ce7a9451eb5 100644 (file)
@@ -965,6 +965,7 @@ void pci_no_aer(void);
 void pci_aer_init(struct pci_dev *dev);
 void pci_aer_exit(struct pci_dev *dev);
 extern const struct attribute_group aer_stats_attr_group;
+extern const struct attribute_group aer_attr_group;
 void pci_aer_clear_fatal_status(struct pci_dev *dev);
 int pci_aer_clear_status(struct pci_dev *dev);
 int pci_aer_raw_clear_status(struct pci_dev *dev);
index 7886a9ad126c3ed750777d9bd01064331311d0f3..70ac66188367201253d96dfe3b57e8168a9b9996 100644 (file)
@@ -627,6 +627,111 @@ const struct attribute_group aer_stats_attr_group = {
        .is_visible = aer_stats_attrs_are_visible,
 };
 
+/*
+ * Ratelimit interval
+ * <=0: disabled with ratelimit.interval = 0
+ * >0: enabled with ratelimit.interval in ms
+ */
+#define aer_ratelimit_interval_attr(name, ratelimit)                   \
+       static ssize_t                                                  \
+       name##_show(struct device *dev, struct device_attribute *attr,  \
+                                        char *buf)                     \
+       {                                                               \
+               struct pci_dev *pdev = to_pci_dev(dev);                 \
+                                                                       \
+               return sysfs_emit(buf, "%d\n",                          \
+                                 pdev->aer_info->ratelimit.interval);  \
+       }                                                               \
+                                                                       \
+       static ssize_t                                                  \
+       name##_store(struct device *dev, struct device_attribute *attr, \
+                    const char *buf, size_t count)                     \
+       {                                                               \
+               struct pci_dev *pdev = to_pci_dev(dev);                 \
+               int interval;                                           \
+                                                                       \
+               if (!capable(CAP_SYS_ADMIN))                            \
+                       return -EPERM;                                  \
+                                                                       \
+               if (kstrtoint(buf, 0, &interval) < 0)                   \
+                       return -EINVAL;                                 \
+                                                                       \
+               if (interval <= 0)                                      \
+                       interval = 0;                                   \
+               else                                                    \
+                       interval = msecs_to_jiffies(interval);          \
+                                                                       \
+               pdev->aer_info->ratelimit.interval = interval;          \
+                                                                       \
+               return count;                                           \
+       }                                                               \
+       static DEVICE_ATTR_RW(name);
+
+#define aer_ratelimit_burst_attr(name, ratelimit)                      \
+       static ssize_t                                                  \
+       name##_show(struct device *dev, struct device_attribute *attr,  \
+                   char *buf)                                          \
+       {                                                               \
+               struct pci_dev *pdev = to_pci_dev(dev);                 \
+                                                                       \
+               return sysfs_emit(buf, "%d\n",                          \
+                                 pdev->aer_info->ratelimit.burst);     \
+       }                                                               \
+                                                                       \
+       static ssize_t                                                  \
+       name##_store(struct device *dev, struct device_attribute *attr, \
+                    const char *buf, size_t count)                     \
+       {                                                               \
+               struct pci_dev *pdev = to_pci_dev(dev);                 \
+               int burst;                                              \
+                                                                       \
+               if (!capable(CAP_SYS_ADMIN))                            \
+                       return -EPERM;                                  \
+                                                                       \
+               if (kstrtoint(buf, 0, &burst) < 0)                      \
+                       return -EINVAL;                                 \
+                                                                       \
+               pdev->aer_info->ratelimit.burst = burst;                \
+                                                                       \
+               return count;                                           \
+       }                                                               \
+       static DEVICE_ATTR_RW(name);
+
+#define aer_ratelimit_attrs(name)                                      \
+       aer_ratelimit_interval_attr(name##_ratelimit_interval_ms,       \
+                                   name##_ratelimit)                   \
+       aer_ratelimit_burst_attr(name##_ratelimit_burst,                \
+                                name##_ratelimit)
+
+aer_ratelimit_attrs(correctable)
+aer_ratelimit_attrs(nonfatal)
+
+static struct attribute *aer_attrs[] = {
+       &dev_attr_correctable_ratelimit_interval_ms.attr,
+       &dev_attr_correctable_ratelimit_burst.attr,
+       &dev_attr_nonfatal_ratelimit_interval_ms.attr,
+       &dev_attr_nonfatal_ratelimit_burst.attr,
+       NULL
+};
+
+static umode_t aer_attrs_are_visible(struct kobject *kobj,
+                                    struct attribute *a, int n)
+{
+       struct device *dev = kobj_to_dev(kobj);
+       struct pci_dev *pdev = to_pci_dev(dev);
+
+       if (!pdev->aer_info)
+               return 0;
+
+       return a->mode;
+}
+
+const struct attribute_group aer_attr_group = {
+       .name = "aer",
+       .attrs = aer_attrs,
+       .is_visible = aer_attrs_are_visible,
+};
+
 static void pci_dev_aer_stats_incr(struct pci_dev *pdev,
                                   struct aer_err_info *info)
 {