[PATCH v2 0/8] Fix long standing AER Error Handling Issues

[PATCH v2 0/8] Fix long standing AER Error Handling Issues

[Naveen Naidu]

This patch series aims at fixing some of the AER error handling issues
we have.

Currently we have the following issues:
 - Confusing message in aer_print_error()
 - aer_err_info not being initialized completely in DPC path before 
   we print the AER logs
 - A bug [1] in clearing of AER registers in the native AER path

[1] https://lore.kernel.org/linux-pci/20151229155822.GA17321@localhost/

The primary aim of this patch series is to converge the APEI path and the
native AER error handling paths. In our current code, we find that we
have two different behaviours (especially when it comes to clearing of
the AER registers) for the same functionality.

This patch series, tries to bring the same semantics and hence more 
commonanlity between the APEI part of code and the native OS 
handling of AER errors.

PATCH 1: 
  - Fixes the first issue

PATCH 2 - 4:
  - Fixes the second issue
  - "Patch 3/8" is dependent on "Patch 2/3" in the series

PATCH 5 - 7
  - Deals with converging the various paths and to bring more
    commonality between them
  - "Patch 6/8" depends on "Patch 1/8"

PATCH 8:
  -  Adds extra information in AER error logs.

Thanks,
Naveen Naidu

Changelog
=========

v2:
  Apologies for the mistake, I forgot to cc the linux-pci mailing list.
  Resent the email with cc to linux-pci.

Naveen Naidu (8):
 [PATCH v2 1/8] PCI/AER: Remove ID from aer_agent_string[]
 [PATCH v2 2/8] PCI: Cleanup struct aer_err_info
 [PATCH v2 3/8] PCI/DPC: Initialize info->id in dpc_process_error()
 [PATCH v2 4/8] PCI/DPC: Use pci_aer_clear_status() in dpc_process_error()
 [PATCH v2 5/8] PCI/DPC: Converge EDR and DPC Path of clearing AER registers
 [PATCH v2 6/8] PCI/AER: Clear error device AER registers in aer_irq()
 [PATCH v2 7/8] PCI/ERR: Remove redundant clearing of AER register in pcie_do_recovery()
 [PATCH v2 8/8] PCI/AER: Include DEVCTL in aer_print_error()

 drivers/pci/pci.h      |  23 +++-
 drivers/pci/pcie/aer.c | 265 ++++++++++++++++++++++++++++-------------
 drivers/pci/pcie/dpc.c |   9 +-
 drivers/pci/pcie/err.c |   9 +-
 4 files changed, 207 insertions(+), 99 deletions(-)

-- 
2.25.1

[PATCH v2 1/8] PCI/AER: Remove ID from aer_agent_string[]

[Naveen Naidu]

Before 010caed4ccb6 ("PCI/AER: Decode Error Source RequesterID")
the AER error logs looked like:

  pcieport 0000:00:03.0: AER: Corrected error received: id=0018
  pcieport 0000:00:03.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, id=0018 (Receiver ID)
  pcieport 0000:00:03.0:   device [1b36:000c] error status/mask=00000040/0000e000
  pcieport 0000:00:03.0:    [ 6] BadTLP

In 010caed4ccb6 ("PCI/AER: Decode Error Source Requester ID"),
the "id" field was removed from the AER error logs, so currently AER
logs look like:

  pcieport 0000:00:03.0: AER: Corrected error received: 0000:00:03:0
  pcieport 0000:00:03.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Receiver ID)
  pcieport 0000:00:03.0:   device [1b36:000c] error status/mask=00000040/0000e000
  pcieport 0000:00:03.0:    [ 6] BadTLP

The second line in the above logs prints "(Receiver ID)", even when
there is no "id" in the log line. This is confusing.

Remove the "ID" from the aer_agent_string[]. The error logs will
look as follows (Sample from dummy error injected by aer-inject):

  pcieport 0000:00:03.0: AER: Corrected error received: 0000:00:03.0
  pcieport 0000:00:03.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Receiver)
  pcieport 0000:00:03.0:   device [1b36:000c] error status/mask=00000040/0000e000
  pcieport 0000:00:03.0:    [ 6] BadTLP

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pcie/aer.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 9784fdcf3006..241ff361b43c 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -516,10 +516,10 @@ static const char *aer_uncorrectable_error_string[] = {
 };
 
 static const char *aer_agent_string[] = {
-	"Receiver ID",
-	"Requester ID",
-	"Completer ID",
-	"Transmitter ID"
+	"Receiver",
+	"Requester",
+	"Completer",
+	"Transmitter"
 };
 
 #define aer_stats_dev_attr(name, stats_array, strings_array,		\
@@ -703,7 +703,7 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 	const char *level;
 
 	if (!info->status) {
-		pci_err(dev, "PCIe Bus Error: severity=%s, type=Inaccessible, (Unregistered Agent ID)\n",
+		pci_err(dev, "PCIe Bus Error: severity=%s, type=Inaccessible, (Unregistered Agent)\n",
 			aer_error_severity_string[info->severity]);
 		goto out;
 	}
-- 
2.25.1

[PATCH v2 2/8] PCI: Cleanup struct aer_err_info

[Naveen Naidu]

The id, status and the mask fields of the struct aer_err_info comes
directly from the registers, hence their sizes should be explicit.

The length of these registers are:
  - id: 16 bits - Represents the Error Source Requester ID
  - status: 32 bits - COR/UNCOR Error Status
  - mask: 32 bits - COR/UNCOR Error Mask

Since the length of the above registers are even, use u16 and u32
to represent their values.

Also remove the __pad fields.

"pahole" was run on the modified struct aer_err_info and the size
remains unchanged.

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pci.h | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 1cce56c2aea0..9be7a966fda7 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -427,18 +427,16 @@ struct aer_err_info {
 	struct pci_dev *dev[AER_MAX_MULTI_ERR_DEVICES];
 	int error_dev_num;
 
-	unsigned int id:16;
+	u16	id;
 
 	unsigned int severity:2;	/* 0:NONFATAL | 1:FATAL | 2:COR */
-	unsigned int __pad1:5;
 	unsigned int multi_error_valid:1;
 
 	unsigned int first_error:5;
-	unsigned int __pad2:2;
 	unsigned int tlp_header_valid:1;
 
-	unsigned int status;		/* COR/UNCOR Error Status */
-	unsigned int mask;		/* COR/UNCOR Error Mask */
+	u32 status;		/* COR/UNCOR Error Status */
+	u32 mask;		/* COR/UNCOR Error Mask */
 	struct aer_header_log_regs tlp;	/* TLP Header */
 };
 
-- 
2.25.1

[PATCH v2 3/8] PCI/DPC: Initialize info->id in dpc_process_error()

[Naveen Naidu]

In the dpc_process_error() path, info->id isn't initialized before being
passed to aer_print_error(). In the corresponding AER path, it is
initialized in aer_isr_one_error().

The error message shown during Coverity Scan is:

  Coverity #1461602
  CID 1461602 (#1 of 1): Uninitialized scalar variable (UNINIT)
  8. uninit_use_in_call: Using uninitialized value info.id when calling aer_print_error.

Initialize the "info->id" before passing it to aer_print_error()

Fixes: 8aefa9b0d910 ("PCI/DPC: Print AER status in DPC event handling")
Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pcie/dpc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index c556e7beafe3..df3f3a10f8bc 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -262,14 +262,14 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
 
 void dpc_process_error(struct pci_dev *pdev)
 {
-	u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
+	u16 cap = pdev->dpc_cap, status, reason, ext_reason;
 	struct aer_err_info info;
 
 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
-	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
+	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &info.id);
 
 	pci_info(pdev, "containment event, status:%#06x source:%#06x\n",
-		 status, source);
+		 status, info.id);
 
 	reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
 	ext_reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT) >> 5;
-- 
2.25.1

[PATCH v2 4/8] PCI/DPC: Use pci_aer_clear_status() in dpc_process_error()

[Naveen Naidu]

dpc_process_error() clears both AER fatal and non fatal status
registers. Instead of clearing each status registers via a different
function call use pci_aer_clear_status().

This helps clean up the code a bit.

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pcie/dpc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index df3f3a10f8bc..faf4a1e77fab 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -288,8 +288,7 @@ void dpc_process_error(struct pci_dev *pdev)
 		 dpc_get_aer_uncorrect_severity(pdev, &info) &&
 		 aer_get_device_error_info(pdev, &info)) {
 		aer_print_error(pdev, &info);
-		pci_aer_clear_nonfatal_status(pdev);
-		pci_aer_clear_fatal_status(pdev);
+		pci_aer_clear_status(pdev);
 	}
 }
 
-- 
2.25.1

[PATCH v2 5/8] PCI/DPC: Converge EDR and DPC Path of clearing AER registers

[Naveen Naidu]

In the EDR path, AER registers are cleared *after* DPC error event is
processed. The process stack in EDR is:

  edr_handle_event()
    dpc_process_error()
    pci_aer_raw_clear_status()
    pcie_do_recovery()

But in DPC path, AER status registers are cleared *while* processing
the error. The process stack in DPC is:

  dpc_handler()
    dpc_process_error()
      pci_aer_clear_status()
    pcie_do_recovery()

In EDR path, AER status registers are cleared irrespective of whether
the error was an RP PIO or unmasked uncorrectable error. But in DPC, the
AER status registers are cleared only when it's an unmasked uncorrectable
error.

This leads to two different behaviours for the same task (handling of
DPC errors) in FFS systems and when native OS has control.

Bring the same semantics for clearing the AER status register in EDR
path and DPC path.

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pcie/dpc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index faf4a1e77fab..68899a3db126 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -288,7 +288,6 @@ void dpc_process_error(struct pci_dev *pdev)
 		 dpc_get_aer_uncorrect_severity(pdev, &info) &&
 		 aer_get_device_error_info(pdev, &info)) {
 		aer_print_error(pdev, &info);
-		pci_aer_clear_status(pdev);
 	}
 }
 
@@ -297,6 +296,7 @@ static irqreturn_t dpc_handler(int irq, void *context)
 	struct pci_dev *pdev = context;
 
 	dpc_process_error(pdev);
+	pci_aer_clear_status(pdev);
 
 	/* We configure DPC so it only triggers on ERR_FATAL */
 	pcie_do_recovery(pdev, pci_channel_io_frozen, dpc_reset_link);
-- 
2.25.1

[PATCH v2 6/8] PCI/AER: Clear error device AER registers in aer_irq()

[Naveen Naidu]

Converge the APEI path and native AER path of clearing the AER registers
of the error device.

In APEI path, the system firmware clears the AER registers before
handing off the record to OS. But in "native AER" path, the execution
path of clearing the AER register is as follows:

  aer_isr_one_error
    aer_print_port_info
      if (find_source_device())
        aer_process_err_devices
          handle_error_source
            pci_write_config_dword(dev, PCI_ERR_COR_STATUS, ...)

The above path has a bug, if the find_source_device() fails, AER
registers are not cleared from the error device. This means, the error
device will keep reporting the error again and again and would lead
to message spew.

Related Bug Report:
  https://lore.kernel.org/linux-pci/20151229155822.GA17321@localhost/
  https://bugzilla.kernel.org/show_bug.cgi?id=109691
  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1521173

The above bug could be avoided, if the AER registers are cleared during
the AER IRQ handler aer_irq(), which would provide guarantee that the AER
error registers are always cleared. This is similar to how APEI handles
these errors.

The main aim is that:

  When an interrupt handler deals with a interrupt, it must *always*
  clear the source of the interrupt.

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pci.h      |  13 ++-
 drivers/pci/pcie/aer.c | 245 ++++++++++++++++++++++++++++-------------
 2 files changed, 182 insertions(+), 76 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9be7a966fda7..eb88d8bfeaf7 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -424,7 +424,6 @@ static inline bool pci_dev_is_added(const struct pci_dev *dev)
 #define AER_MAX_MULTI_ERR_DEVICES	5	/* Not likely to have more */
 
 struct aer_err_info {
-	struct pci_dev *dev[AER_MAX_MULTI_ERR_DEVICES];
 	int error_dev_num;
 
 	u16	id;
@@ -440,6 +439,18 @@ struct aer_err_info {
 	struct aer_header_log_regs tlp;	/* TLP Header */
 };
 
+/* Preliminary AER error information processed from Root port */
+struct aer_devices_err_info {
+	struct pci_dev *dev[AER_MAX_MULTI_ERR_DEVICES];
+	struct aer_err_info err_info;
+};
+
+/* AER information associated with each error device */
+struct aer_dev_err_info {
+	struct pci_dev *dev;
+	struct aer_err_info err_info;
+};
+
 int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info);
 void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
 #endif	/* CONFIG_PCIEAER */
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 241ff361b43c..91f91d6ab052 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -36,6 +36,18 @@
 
 #define AER_ERROR_SOURCES_MAX		128
 
+/*
+ * There can be 128 maximum error sources (AER_ERROR_SOURCES_MAX) and each
+ * error source can have maximum of 5 error devices (AER_MAX_MULTI_ERR_DEVICES)
+ * so the maximum error devices we can report is:
+ *
+ * AER_ERROR_DEVICES_MAX = AER_ERROR_SOURCES_MAX * AER_MAX_MULTI_ERR_DEVICES == (128 * 5) == 640
+ *
+ * But since, the size in KFIFO should be a power of two, the closest value
+ * to 640 is 1024
+ */
+# define AER_ERROR_DEVICES_MAX		1024
+
 #define AER_MAX_TYPEOF_COR_ERRS		16	/* as per PCI_ERR_COR_STATUS */
 #define AER_MAX_TYPEOF_UNCOR_ERRS	27	/* as per PCI_ERR_UNCOR_STATUS*/
 
@@ -46,7 +58,7 @@ struct aer_err_source {
 
 struct aer_rpc {
 	struct pci_dev *rpd;		/* Root Port device */
-	DECLARE_KFIFO(aer_fifo, struct aer_err_source, AER_ERROR_SOURCES_MAX);
+	DECLARE_KFIFO(aer_fifo, struct aer_dev_err_info, AER_ERROR_DEVICES_MAX);
 };
 
 /* AER stats for the device */
@@ -806,11 +818,11 @@ void cper_print_aer(struct pci_dev *dev, int aer_severity,
  * @e_info: pointer to error info
  * @dev: pointer to pci_dev to be added
  */
-static int add_error_device(struct aer_err_info *e_info, struct pci_dev *dev)
+static int add_error_device(struct aer_devices_err_info *e_dev, struct pci_dev *dev)
 {
-	if (e_info->error_dev_num < AER_MAX_MULTI_ERR_DEVICES) {
-		e_info->dev[e_info->error_dev_num] = pci_dev_get(dev);
-		e_info->error_dev_num++;
+	if (e_dev->err_info.error_dev_num < AER_MAX_MULTI_ERR_DEVICES) {
+		e_dev->dev[e_dev->err_info.error_dev_num] = pci_dev_get(dev);
+		e_dev->err_info.error_dev_num++;
 		return 0;
 	}
 	return -ENOSPC;
@@ -877,18 +889,18 @@ static bool is_error_source(struct pci_dev *dev, struct aer_err_info *e_info)
 
 static int find_device_iter(struct pci_dev *dev, void *data)
 {
-	struct aer_err_info *e_info = (struct aer_err_info *)data;
+	struct aer_devices_err_info *e_dev = (struct aer_devices_err_info *)data;
 
-	if (is_error_source(dev, e_info)) {
+	if (is_error_source(dev, &e_dev->err_info)) {
 		/* List this device */
-		if (add_error_device(e_info, dev)) {
+		if (add_error_device(e_dev, dev)) {
 			/* We cannot handle more... Stop iteration */
 			/* TODO: Should print error message here? */
 			return 1;
 		}
 
 		/* If there is only a single error, stop iteration */
-		if (!e_info->multi_error_valid)
+		if (!e_dev->err_info.multi_error_valid)
 			return 1;
 	}
 	return 0;
@@ -907,26 +919,26 @@ static int find_device_iter(struct pci_dev *dev, void *data)
  * e_info->error_dev_num and e_info->dev[], based on the given information.
  */
 static bool find_source_device(struct pci_dev *parent,
-		struct aer_err_info *e_info)
+		struct aer_devices_err_info *e_dev)
 {
 	struct pci_dev *dev = parent;
 	int result;
 
 	/* Must reset in this function */
-	e_info->error_dev_num = 0;
+	e_dev->err_info.error_dev_num = 0;
 
 	/* Is Root Port an agent that sends error message? */
-	result = find_device_iter(dev, e_info);
+	result = find_device_iter(dev, e_dev);
 	if (result)
 		return true;
 
 	if (pci_pcie_type(parent) == PCI_EXP_TYPE_RC_EC)
-		pcie_walk_rcec(parent, find_device_iter, e_info);
+		pcie_walk_rcec(parent, find_device_iter, e_dev);
 	else
-		pci_walk_bus(parent->subordinate, find_device_iter, e_info);
+		pci_walk_bus(parent->subordinate, find_device_iter, e_dev);
 
-	if (!e_info->error_dev_num) {
-		pci_info(parent, "can't find device of ID%04x\n", e_info->id);
+	if (!e_dev->err_info.error_dev_num) {
+		pci_info(parent, "can't find device of ID%04x\n", e_dev->err_info.id);
 		return false;
 	}
 	return true;
@@ -940,24 +952,42 @@ static bool find_source_device(struct pci_dev *parent,
  * Invoked when an error being detected by Root Port.
  */
 static void handle_error_source(struct pci_dev *dev, struct aer_err_info *info)
+{
+	/*
+	 * Correctable error does not need software intervention.
+	 * No need to go through error recovery process.
+	 */
+	if (info->severity == AER_NONFATAL)
+		pcie_do_recovery(dev, pci_channel_io_normal, aer_root_reset);
+	else if (info->severity == AER_FATAL)
+		pcie_do_recovery(dev, pci_channel_io_frozen, aer_root_reset);
+	pci_dev_put(dev);
+}
+
+/**
+ * clear_error_source_aer_registers - clear AER registers of the error source device
+ * @dev: pointer to pci_dev data structure of error source device
+ * @info: comprehensive error information
+ *
+ * Invoked when an error being detected by Root Port but before we handle the
+ * error.
+ */
+static void clear_error_source_aer_registers(struct pci_dev *dev, struct aer_err_info info)
 {
 	int aer = dev->aer_cap;
 
-	if (info->severity == AER_CORRECTABLE) {
-		/*
-		 * Correctable error does not need software intervention.
-		 * No need to go through error recovery process.
-		 */
+	if (info.severity == AER_CORRECTABLE) {
 		if (aer)
 			pci_write_config_dword(dev, aer + PCI_ERR_COR_STATUS,
-					info->status);
+					info.status);
 		if (pcie_aer_is_native(dev))
 			pcie_clear_device_status(dev);
-	} else if (info->severity == AER_NONFATAL)
-		pcie_do_recovery(dev, pci_channel_io_normal, aer_root_reset);
-	else if (info->severity == AER_FATAL)
-		pcie_do_recovery(dev, pci_channel_io_frozen, aer_root_reset);
-	pci_dev_put(dev);
+	} else if (info.severity == AER_NONFATAL) {
+		pci_aer_clear_nonfatal_status(dev);
+	} else if (info.severity == AER_FATAL) {
+		pci_aer_clear_fatal_status(dev);
+	}
+
 }
 
 #ifdef CONFIG_ACPI_APEI_PCIEAER
@@ -1093,70 +1123,112 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
 	return 1;
 }
 
-static inline void aer_process_err_devices(struct aer_err_info *e_info)
-{
-	int i;
-
-	/* Report all before handle them, not to lost records by reset etc. */
-	for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
-		if (aer_get_device_error_info(e_info->dev[i], e_info))
-			aer_print_error(e_info->dev[i], e_info);
-	}
-	for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
-		if (aer_get_device_error_info(e_info->dev[i], e_info))
-			handle_error_source(e_info->dev[i], e_info);
-	}
-}
-
 /**
- * aer_isr_one_error - consume an error detected by root port
- * @rpc: pointer to the root port which holds an error
+ * aer_find_corr_error_source_device - find the error source which detected the corrected error
+ * @rp: pointer to Root Port pci_dev data structure
  * @e_src: pointer to an error source
+ * @e_info: including detailed error information such like id
+ *
+ * Return true if found.
+ *
+ * Process the error information received at the Root Port, set these values
+ * in the aer_devices_err_info and find all the devices that are related to
+ * the error.
  */
-static void aer_isr_one_error(struct aer_rpc *rpc,
-		struct aer_err_source *e_src)
+static bool aer_find_corr_error_source_device(struct pci_dev *rp,
+					struct aer_err_source *e_src,
+					struct aer_devices_err_info *e_info)
 {
-	struct pci_dev *pdev = rpc->rpd;
-	struct aer_err_info 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.
-	 */
 	if (e_src->status & PCI_ERR_ROOT_COR_RCV) {
-		e_info.id = ERR_COR_ID(e_src->id);
-		e_info.severity = AER_CORRECTABLE;
+		e_info->err_info.id = ERR_COR_ID(e_src->id);
+		e_info->err_info.severity = AER_CORRECTABLE;
 
 		if (e_src->status & PCI_ERR_ROOT_MULTI_COR_RCV)
-			e_info.multi_error_valid = 1;
+			e_info->err_info.multi_error_valid = 1;
 		else
-			e_info.multi_error_valid = 0;
-		aer_print_port_info(pdev, &e_info);
+			e_info->err_info.multi_error_valid = 0;
 
-		if (find_source_device(pdev, &e_info))
-			aer_process_err_devices(&e_info);
+		if (!find_source_device(rp, e_info))
+			return false;
 	}
+	return true;
+}
 
+/**
+ * aer_find_corr_error_source_device - find the error source which detected the uncorrected error
+ * @rp: pointer to Root Port pci_dev data structure
+ * @e_src: pointer to an error source
+ * @e_info: including detailed error information such like id
+ *
+ * Return true if found.
+ *
+ * Process the error information received at the Root Port, set these values
+ * in the aer_devices_err_info and find all the devices that are related to
+ * the error.
+ */
+static bool aer_find_uncorr_error_source_device(struct pci_dev *rp,
+					struct aer_err_source *e_src,
+					struct aer_devices_err_info *e_info)
+{
 	if (e_src->status & PCI_ERR_ROOT_UNCOR_RCV) {
-		e_info.id = ERR_UNCOR_ID(e_src->id);
+		e_info->err_info.id = ERR_UNCOR_ID(e_src->id);
 
 		if (e_src->status & PCI_ERR_ROOT_FATAL_RCV)
-			e_info.severity = AER_FATAL;
+			e_info->err_info.severity = AER_FATAL;
 		else
-			e_info.severity = AER_NONFATAL;
+			e_info->err_info.severity = AER_NONFATAL;
 
 		if (e_src->status & PCI_ERR_ROOT_MULTI_UNCOR_RCV)
-			e_info.multi_error_valid = 1;
+			e_info->err_info.multi_error_valid = 1;
 		else
-			e_info.multi_error_valid = 0;
+			e_info->err_info.multi_error_valid = 0;
+
+		if (!find_source_device(rp, e_info))
+			return false;
+	}
 
-		aer_print_port_info(pdev, &e_info);
+	return true;
+}
 
-		if (find_source_device(pdev, &e_info))
-			aer_process_err_devices(&e_info);
+/**
+ * aer_isr_one_error - consume an error detected by root port
+ * @rp: pointer to Root Port pci_dev data structure
+ * @e_dev: pointer to an error device
+ */
+static void aer_isr_one_error(struct pci_dev *rp, struct aer_dev_err_info *e_dev)
+{
+	aer_print_port_info(rp, &e_dev->err_info);
+	aer_print_error(e_dev->dev, &e_dev->err_info);
+	handle_error_source(e_dev->dev, &e_dev->err_info);
+}
+
+static bool aer_add_err_devices_to_queue(struct aer_rpc *rpc,
+		struct aer_devices_err_info *e_info)
+{
+	int i;
+	struct aer_dev_err_info *e_dev;
+
+	e_dev = kzalloc(sizeof(*e_dev), GFP_ATOMIC);
+	if (!e_dev)
+		return false;
+
+	for (i = 0; i < e_info->err_info.error_dev_num && e_info->dev[i]; i++) {
+		e_dev->err_info = e_info->err_info;
+		e_dev->dev = e_info->dev[i];
+
+		/*
+		 * Store the AER register information for each error device on
+		 * the queue
+		 */
+		if (aer_get_device_error_info(e_dev->dev, &e_dev->err_info)) {
+			if (!kfifo_put(&rpc->aer_fifo, *e_dev))
+				return false;
+
+			clear_error_source_aer_registers(e_dev->dev, e_dev->err_info);
+		}
 	}
+
+	return true;
 }
 
 /**
@@ -1170,13 +1242,13 @@ static irqreturn_t aer_isr(int irq, void *context)
 {
 	struct pcie_device *dev = (struct pcie_device *)context;
 	struct aer_rpc *rpc = get_service_data(dev);
-	struct aer_err_source e_src;
+	struct aer_dev_err_info e_dev;
 
 	if (kfifo_is_empty(&rpc->aer_fifo))
 		return IRQ_NONE;
 
-	while (kfifo_get(&rpc->aer_fifo, &e_src))
-		aer_isr_one_error(rpc, &e_src);
+	while (kfifo_get(&rpc->aer_fifo, &e_dev))
+		aer_isr_one_error(rpc->rpd, &e_dev);
 	return IRQ_HANDLED;
 }
 
@@ -1194,6 +1266,11 @@ static irqreturn_t aer_irq(int irq, void *context)
 	struct pci_dev *rp = rpc->rpd;
 	int aer = rp->aer_cap;
 	struct aer_err_source e_src = {};
+	struct aer_devices_err_info *e_info;
+
+	e_info = kzalloc(sizeof(*e_info), GFP_ATOMIC);
+	if (!e_info)
+		return IRQ_NONE;
 
 	pci_read_config_dword(rp, aer + PCI_ERR_ROOT_STATUS, &e_src.status);
 	if (!(e_src.status & (PCI_ERR_ROOT_UNCOR_RCV|PCI_ERR_ROOT_COR_RCV)))
@@ -1202,8 +1279,26 @@ static irqreturn_t aer_irq(int irq, void *context)
 	pci_read_config_dword(rp, aer + PCI_ERR_ROOT_ERR_SRC, &e_src.id);
 	pci_write_config_dword(rp, aer + PCI_ERR_ROOT_STATUS, e_src.status);
 
-	if (!kfifo_put(&rpc->aer_fifo, e_src))
-		return IRQ_HANDLED;
+	pci_rootport_aer_stats_incr(rp, &e_src);
+
+	/*
+	 * There is a possibility that both correctable error and
+	 * uncorrectable error are being logged. Find the devices which caused
+	 * correctable errors first so that they can be added to the queue first
+	 * and will be reported first.
+	 *
+	 * Before adding the error device to the queue to be handled, clear the
+	 * AER status registers.
+	 */
+	if (aer_find_corr_error_source_device(rp, &e_src, e_info)) {
+		if (!aer_add_err_devices_to_queue(rpc, e_info))
+			return IRQ_NONE;
+	}
+
+	if (aer_find_uncorr_error_source_device(rp, &e_src, e_info)) {
+		if (!aer_add_err_devices_to_queue(rpc, e_info))
+			return IRQ_NONE;
+	}
 
 	return IRQ_WAKE_THREAD;
 }
-- 
2.25.1

[PATCH v2 7/8] PCI/ERR: Remove redundant clearing of AER register in pcie_do_recovery()

[Naveen Naidu]

pcie_do_recovery() is shared across the following paths:
 - ACPI APEI
 - Native AER path
 - EDR
 - DPC

ACPI APEI
==========

  ghes_handle_aer()
    aer_recover_queue()
      kfifo_in_spinlocked(aer_recover_ring)

  aer_recover_work_func()
    while (kfifo_get(aer_recover_ring))
      pcie_do_recovery()

In this path the system firmware clears the AER registers before
handing off the record to the OS in ghes_handle_aer()

Native AER
==========

 aer_irq()
   aer_add_err_devices_to_queue()
     kfifo_put(&rpc->aer_fifo, *e_dev)
     clear_error_source_aer_registers()   <---- AER registers are cleard

 aer_isr()
   aer_isr_one_error()
    handle_error_source()
      pcie_do_recovery()

The AER registers are cleared during the handling of IRQ, i.e before we
the recovery starts.

DPC
=====

  dpc_handler()
    dpc_process_error()
    pci_aer_clear_status()       <---- AER registers are cleared
    pcie_do_recovery()

EDR
====

  edr_handle_event()
    dpc_process_error()
    pci_aer_raw_clear_status()  <---- AER registers are cleared
    pcie_do_recovery()

In all the above paths, the AER registers are cleared before
pcie_do_recovery(). The non fatal status AER registers are again cleared
in pcie_do_recovery(). This is redundant.

Remove redundant clearing of AER register in pcie_do_recovery()

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pcie/err.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index b576aa890c76..fe04b0ae22f4 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -231,14 +231,11 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 
 	/*
 	 * If we have native control of AER, clear error status in the device
-	 * that detected the error.  If the platform retained control of AER,
-	 * it is responsible for clearing this status.  In that case, the
-	 * signaling device may not even be visible to the OS.
+	 * that detected the error.
 	 */
-	if (host->native_aer || pcie_ports_native) {
+	if (host->native_aer || pcie_ports_native)
 		pcie_clear_device_status(dev);
-		pci_aer_clear_nonfatal_status(dev);
-	}
+
 	pci_info(bridge, "device recovery successful\n");
 	return status;
 
-- 
2.25.1

[PATCH 8/8] PCI/AER: Include DEVCTL in aer_print_error()

[Naveen Naidu]

Print the contents of Device Control Register of the device which
detected the error. This might help in faster error diagnosis.

Sample output from dummy error injected by aer-inject:

  pcieport 0000:00:03.0: AER: Corrected error received: 0000:00:03.0
  pcieport 0000:00:03.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Receiver)
  pcieport 0000:00:03.0:   device [1b36:000c] error status/mask=00000040/0000e000, devctl=0x000f
  pcieport 0000:00:03.0:    [ 6] BadTLP

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pci.h      |  2 ++
 drivers/pci/pcie/aer.c | 10 ++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index eb88d8bfeaf7..48ed7f91113b 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -437,6 +437,8 @@ struct aer_err_info {
 	u32 status;		/* COR/UNCOR Error Status */
 	u32 mask;		/* COR/UNCOR Error Mask */
 	struct aer_header_log_regs tlp;	/* TLP Header */
+
+	u16 devctl;
 };
 
 /* Preliminary AER error information processed from Root port */
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 91f91d6ab052..42cae01b6887 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -729,8 +729,8 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 		   aer_error_severity_string[info->severity],
 		   aer_error_layer[layer], aer_agent_string[agent]);
 
-	pci_printk(level, dev, "  device [%04x:%04x] error status/mask=%08x/%08x\n",
-		   dev->vendor, dev->device, info->status, info->mask);
+	pci_printk(level, dev, "  device [%04x:%04x] error status/mask=%08x/%08x, devctl=%#06x\n",
+		   dev->vendor, dev->device, info->status, info->mask, info->devctl);
 
 	__aer_print_error(dev, info);
 
@@ -1083,6 +1083,12 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
 	if (!aer)
 		return 0;
 
+	/*
+	 * Cache the value of Device Control Register now, because later the
+	 * device might not be available
+	 */
+	pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &info->devctl);
+
 	if (info->severity == AER_CORRECTABLE) {
 		pci_read_config_dword(dev, aer + PCI_ERR_COR_STATUS,
 			&info->status);
-- 
2.25.1

[PATCH v2 8/8] PCI/AER: Include DEVCTL in aer_print_error()

[Naveen Naidu]

Print the contents of Device Control Register of the device which
detected the error. This might help in faster error diagnosis.

Sample output from dummy error injected by aer-inject:

  pcieport 0000:00:03.0: AER: Corrected error received: 0000:00:03.0
  pcieport 0000:00:03.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Receiver)
  pcieport 0000:00:03.0:   device [1b36:000c] error status/mask=00000040/0000e000, devctl=0x000f
  pcieport 0000:00:03.0:    [ 6] BadTLP

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pci.h      |  2 ++
 drivers/pci/pcie/aer.c | 10 ++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index eb88d8bfeaf7..48ed7f91113b 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -437,6 +437,8 @@ struct aer_err_info {
 	u32 status;		/* COR/UNCOR Error Status */
 	u32 mask;		/* COR/UNCOR Error Mask */
 	struct aer_header_log_regs tlp;	/* TLP Header */
+
+	u16 devctl;
 };
 
 /* Preliminary AER error information processed from Root port */
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 91f91d6ab052..42cae01b6887 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -729,8 +729,8 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 		   aer_error_severity_string[info->severity],
 		   aer_error_layer[layer], aer_agent_string[agent]);
 
-	pci_printk(level, dev, "  device [%04x:%04x] error status/mask=%08x/%08x\n",
-		   dev->vendor, dev->device, info->status, info->mask);
+	pci_printk(level, dev, "  device [%04x:%04x] error status/mask=%08x/%08x, devctl=%#06x\n",
+		   dev->vendor, dev->device, info->status, info->mask, info->devctl);
 
 	__aer_print_error(dev, info);
 
@@ -1083,6 +1083,12 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
 	if (!aer)
 		return 0;
 
+	/*
+	 * Cache the value of Device Control Register now, because later the
+	 * device might not be available
+	 */
+	pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &info->devctl);
+
 	if (info->severity == AER_CORRECTABLE) {
 		pci_read_config_dword(dev, aer + PCI_ERR_COR_STATUS,
 			&info->status);
-- 
2.25.1