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From: "Wang, Qingshun" <qingshun.wang@linux.intel.com>
To: linux-pci@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org,
	linux-acpi@vger.kernel.org
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	Robert Richter <rrichter@amd.com>,
	linux-kernel@vger.kernel.org,
	linux-cxl@vger.kernel.org,
	linux-edac@vger.kernel.org,
	"Wang, Qingshun" <qingshun.wang@linux.intel.com>
Subject: [PATCH v2 1/4] PCI/AER: Store more information in aer_err_info
Date: Thu, 25 Jan 2024 14:27:59 +0800
Message-ID: <20240125062802.50819-2-qingshun.wang@linux.intel.com>
In-Reply-To: <20240125062802.50819-1-qingshun.wang@linux.intel.com>
References: <20240125062802.50819-1-qingshun.wang@linux.intel.com>
Precedence: bulk
MIME-Version: 1.0
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When Advisory Non-Fatal errors are raised, both correctable and
uncorrectable error statuses will be set. The current kernel code cannot
store both statuses at the same time, thus failing to handle ANFE properly.
In addition, to avoid clearing UEs that are not ANFE by accident, UE
severity and Device Status also need to be recorded: any fatal UE cannot
be ANFE, and if Fatal/Non-Fatal Error Detected is set in Device Status, do
not take any assumption and let UE handler to clear UE status.

Store status and mask of both correctable and uncorrectable errors in
aer_err_info. The severity of UEs and the values of the Device Status
register are also recorded, which will be used to determine UEs that should
be handled by the ANFE handler. Refactor the rest of the code to use
cor/uncor_status and cor/uncor_mask fields instead of status and mask
fields.

Signed-off-by: "Wang, Qingshun" <qingshun.wang@linux.intel.com>
---
 drivers/acpi/apei/ghes.c | 10 ++++-
 drivers/cxl/core/pci.c   |  6 ++-
 drivers/pci/pci.h        |  8 +++-
 drivers/pci/pcie/aer.c   | 93 ++++++++++++++++++++++++++--------------
 include/linux/aer.h      |  4 +-
 include/linux/pci.h      | 27 ++++++++++++
 6 files changed, 111 insertions(+), 37 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 7b7c605166e0..6034039d5cff 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -593,6 +593,8 @@ static void ghes_handle_aer(struct acpi_hest_generic_data *gdata)
 
 	if (pcie_err->validation_bits & CPER_PCIE_VALID_DEVICE_ID &&
 	    pcie_err->validation_bits & CPER_PCIE_VALID_AER_INFO) {
+		struct pcie_capability_regs *pcie_caps;
+		u16 device_status = 0;
 		unsigned int devfn;
 		int aer_severity;
 		u8 *aer_info;
@@ -615,11 +617,17 @@ static void ghes_handle_aer(struct acpi_hest_generic_data *gdata)
 			return;
 		memcpy(aer_info, pcie_err->aer_info, sizeof(struct aer_capability_regs));
 
+		if (pcie_err->validation_bits & CPER_PCIE_VALID_CAPABILITY) {
+			pcie_caps = (struct pcie_capability_regs *)pcie_err->capability;
+			device_status = pcie_caps->device_status;
+		}
+
 		aer_recover_queue(pcie_err->device_id.segment,
 				  pcie_err->device_id.bus,
 				  devfn, aer_severity,
 				  (struct aer_capability_regs *)
-				  aer_info);
+				  aer_info,
+				  device_status);
 	}
 #endif
 }
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 6c9c8d92f8f7..9111a4415a63 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -903,6 +903,7 @@ static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds)
 	struct aer_capability_regs aer_regs;
 	struct cxl_dport *dport;
 	struct cxl_port *port;
+	u16 device_status;
 	int severity;
 
 	port = cxl_pci_find_port(pdev, &dport);
@@ -917,7 +918,10 @@ static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds)
 	if (!cxl_rch_get_aer_severity(&aer_regs, &severity))
 		return;
 
-	pci_print_aer(pdev, severity, &aer_regs);
+	if (pcie_capability_read_word(pdev, PCI_EXP_DEVSTA, &device_status))
+		return;
+
+	pci_print_aer(pdev, severity, &aer_regs, device_status);
 
 	if (severity == AER_CORRECTABLE)
 		cxl_handle_rdport_cor_ras(cxlds, dport);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 2336a8d1edab..f881a1b42f14 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -407,8 +407,12 @@ struct aer_err_info {
 	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 cor_mask;		/* COR Error Mask */
+	u32 cor_status;		/* COR Error Status */
+	u32 uncor_mask;		/* UNCOR Error Mask */
+	u32 uncor_status;	/* UNCOR Error Status */
+	u32 uncor_severity;	/* UNCOR Error Severity */
+	u16 device_status;
 	struct aer_header_log_regs tlp;	/* TLP Header */
 };
 
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 05fc30bb5134..6583dcf50977 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -615,7 +615,7 @@ const struct attribute_group aer_stats_attr_group = {
 static void pci_dev_aer_stats_incr(struct pci_dev *pdev,
 				   struct aer_err_info *info)
 {
-	unsigned long status = info->status & ~info->mask;
+	unsigned long status;
 	int i, max = -1;
 	u64 *counter = NULL;
 	struct aer_stats *aer_stats = pdev->aer_stats;
@@ -625,16 +625,19 @@ static void pci_dev_aer_stats_incr(struct pci_dev *pdev,
 
 	switch (info->severity) {
 	case AER_CORRECTABLE:
+		status = info->cor_status & ~info->cor_mask;
 		aer_stats->dev_total_cor_errs++;
 		counter = &aer_stats->dev_cor_errs[0];
 		max = AER_MAX_TYPEOF_COR_ERRS;
 		break;
 	case AER_NONFATAL:
+		status = info->uncor_status & ~info->uncor_mask;
 		aer_stats->dev_total_nonfatal_errs++;
 		counter = &aer_stats->dev_nonfatal_errs[0];
 		max = AER_MAX_TYPEOF_UNCOR_ERRS;
 		break;
 	case AER_FATAL:
+		status = info->uncor_status & ~info->uncor_mask;
 		aer_stats->dev_total_fatal_errs++;
 		counter = &aer_stats->dev_fatal_errs[0];
 		max = AER_MAX_TYPEOF_UNCOR_ERRS;
@@ -674,15 +677,17 @@ static void __print_tlp_header(struct pci_dev *dev,
 static void __aer_print_error(struct pci_dev *dev,
 			      struct aer_err_info *info)
 {
+	unsigned long status;
 	const char **strings;
-	unsigned long status = info->status & ~info->mask;
 	const char *level, *errmsg;
 	int i;
 
 	if (info->severity == AER_CORRECTABLE) {
+		status = info->cor_status & ~info->cor_mask;
 		strings = aer_correctable_error_string;
 		level = KERN_WARNING;
 	} else {
+		status = info->uncor_status & ~info->uncor_mask;
 		strings = aer_uncorrectable_error_string;
 		level = KERN_ERR;
 	}
@@ -700,18 +705,27 @@ static void __aer_print_error(struct pci_dev *dev,
 
 void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 {
+	u32 status, mask;
 	int layer, agent;
 	int id = pci_dev_id(dev);
 	const char *level;
 
-	if (!info->status) {
+	if (info->severity == AER_CORRECTABLE) {
+		status = info->cor_status;
+		mask = info->cor_mask;
+	} else {
+		status = info->uncor_status;
+		mask = info->uncor_mask;
+	}
+
+	if (!status) {
 		pci_err(dev, "PCIe Bus Error: severity=%s, type=Inaccessible, (Unregistered Agent ID)\n",
 			aer_error_severity_string[info->severity]);
 		goto out;
 	}
 
-	layer = AER_GET_LAYER_ERROR(info->severity, info->status);
-	agent = AER_GET_AGENT(info->severity, info->status);
+	layer = AER_GET_LAYER_ERROR(info->severity, status);
+	agent = AER_GET_AGENT(info->severity, status);
 
 	level = (info->severity == AER_CORRECTABLE) ? KERN_WARNING : KERN_ERR;
 
@@ -720,7 +734,7 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 		   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);
+		   dev->vendor, dev->device, status, mask);
 
 	__aer_print_error(dev, info);
 
@@ -731,7 +745,7 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 	if (info->id && info->error_dev_num > 1 && info->id == id)
 		pci_err(dev, "  Error of this Agent is reported first\n");
 
-	trace_aer_event(dev_name(&dev->dev), (info->status & ~info->mask),
+	trace_aer_event(dev_name(&dev->dev), (status & ~mask),
 			info->severity, info->tlp_header_valid, &info->tlp);
 }
 
@@ -763,7 +777,7 @@ EXPORT_SYMBOL_GPL(cper_severity_to_aer);
 #endif
 
 void pci_print_aer(struct pci_dev *dev, int aer_severity,
-		   struct aer_capability_regs *aer)
+		   struct aer_capability_regs *aer, u16 device_status)
 {
 	int layer, agent, tlp_header_valid = 0;
 	u32 status, mask;
@@ -783,8 +797,12 @@ void pci_print_aer(struct pci_dev *dev, int aer_severity,
 
 	memset(&info, 0, sizeof(info));
 	info.severity = aer_severity;
-	info.status = status;
-	info.mask = mask;
+	info.cor_status = aer->cor_status;
+	info.cor_mask = aer->cor_mask;
+	info.uncor_status = aer->uncor_status;
+	info.uncor_severity = aer->uncor_severity;
+	info.uncor_mask = aer->uncor_mask;
+	info.device_status = device_status;
 	info.first_error = PCI_ERR_CAP_FEP(aer->cap_control);
 
 	pci_err(dev, "aer_status: 0x%08x, aer_mask: 0x%08x\n", status, mask);
@@ -996,9 +1014,9 @@ static bool cxl_error_is_native(struct pci_dev *dev)
 static bool is_internal_error(struct aer_err_info *info)
 {
 	if (info->severity == AER_CORRECTABLE)
-		return info->status & PCI_ERR_COR_INTERNAL;
+		return info->cor_status & PCI_ERR_COR_INTERNAL;
 
-	return info->status & PCI_ERR_UNC_INTN;
+	return info->uncor_status & PCI_ERR_UNC_INTN;
 }
 
 static int cxl_rch_handle_error_iter(struct pci_dev *dev, void *data)
@@ -1097,7 +1115,7 @@ static void pci_aer_handle_error(struct pci_dev *dev, struct aer_err_info *info)
 		 */
 		if (aer)
 			pci_write_config_dword(dev, aer + PCI_ERR_COR_STATUS,
-					info->status);
+					info->cor_status);
 		if (pcie_aer_is_native(dev)) {
 			struct pci_driver *pdrv = dev->driver;
 
@@ -1128,6 +1146,7 @@ struct aer_recover_entry {
 	u8	devfn;
 	u16	domain;
 	int	severity;
+	u16	device_status;
 	struct aer_capability_regs *regs;
 };
 
@@ -1148,7 +1167,7 @@ static void aer_recover_work_func(struct work_struct *work)
 			       PCI_SLOT(entry.devfn), PCI_FUNC(entry.devfn));
 			continue;
 		}
-		pci_print_aer(pdev, entry.severity, entry.regs);
+		pci_print_aer(pdev, entry.severity, entry.regs, entry.device_status);
 		/*
 		 * Memory for aer_capability_regs(entry.regs) is being allocated from the
 		 * ghes_estatus_pool to protect it from overwriting when multiple sections
@@ -1177,7 +1196,7 @@ static DEFINE_SPINLOCK(aer_recover_ring_lock);
 static DECLARE_WORK(aer_recover_work, aer_recover_work_func);
 
 void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
-		       int severity, struct aer_capability_regs *aer_regs)
+		       int severity, struct aer_capability_regs *aer_regs, u16 device_status)
 {
 	struct aer_recover_entry entry = {
 		.bus		= bus,
@@ -1185,6 +1204,7 @@ void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
 		.domain		= domain,
 		.severity	= severity,
 		.regs		= aer_regs,
+		.device_status	= device_status,
 	};
 
 	if (kfifo_in_spinlocked(&aer_recover_ring, &entry, 1,
@@ -1213,38 +1233,49 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
 	int temp;
 
 	/* Must reset in this function */
-	info->status = 0;
+	info->cor_status = 0;
+	info->uncor_status = 0;
+	info->uncor_severity = 0;
 	info->tlp_header_valid = 0;
 
 	/* The device might not support AER */
 	if (!aer)
 		return 0;
 
-	if (info->severity == AER_CORRECTABLE) {
+	if (info->severity == AER_CORRECTABLE ||
+	    info->severity == AER_NONFATAL ||
+	    type == PCI_EXP_TYPE_ROOT_PORT ||
+	    type == PCI_EXP_TYPE_RC_EC ||
+	    type == PCI_EXP_TYPE_DOWNSTREAM) {
+		/* Link is healthy for IO reads */
 		pci_read_config_dword(dev, aer + PCI_ERR_COR_STATUS,
-			&info->status);
+				      &info->cor_status);
 		pci_read_config_dword(dev, aer + PCI_ERR_COR_MASK,
-			&info->mask);
-		if (!(info->status & ~info->mask))
-			return 0;
-	} else if (type == PCI_EXP_TYPE_ROOT_PORT ||
-		   type == PCI_EXP_TYPE_RC_EC ||
-		   type == PCI_EXP_TYPE_DOWNSTREAM ||
-		   info->severity == AER_NONFATAL) {
-
-		/* Link is still healthy for IO reads */
+				      &info->cor_mask);
 		pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS,
-			&info->status);
+				      &info->uncor_status);
+		pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_SEVER,
+				      &info->uncor_severity);
 		pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_MASK,
-			&info->mask);
-		if (!(info->status & ~info->mask))
+				      &info->uncor_mask);
+		pcie_capability_read_word(dev, PCI_EXP_DEVSTA,
+					  &info->device_status);
+	} else {
+		return 1;
+	}
+
+	if (info->severity == AER_CORRECTABLE) {
+		if (!(info->cor_status & ~info->cor_mask))
+			return 0;
+	} else {
+		if (!(info->uncor_status & ~info->uncor_mask))
 			return 0;
 
 		/* Get First Error Pointer */
 		pci_read_config_dword(dev, aer + PCI_ERR_CAP, &temp);
 		info->first_error = PCI_ERR_CAP_FEP(temp);
 
-		if (info->status & AER_LOG_TLP_MASKS) {
+		if (info->uncor_status & AER_LOG_TLP_MASKS) {
 			info->tlp_header_valid = 1;
 			pci_read_config_dword(dev,
 				aer + PCI_ERR_HEADER_LOG, &info->tlp.dw0);
diff --git a/include/linux/aer.h b/include/linux/aer.h
index ae0fae70d4bd..38ac802250ac 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -52,9 +52,9 @@ static inline int pcie_aer_is_native(struct pci_dev *dev) { return 0; }
 #endif
 
 void pci_print_aer(struct pci_dev *dev, int aer_severity,
-		    struct aer_capability_regs *aer);
+		    struct aer_capability_regs *aer, u16 device_status);
 int cper_severity_to_aer(int cper_severity);
 void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
-		       int severity, struct aer_capability_regs *aer_regs);
+		       int severity, struct aer_capability_regs *aer_regs, u16 device_status);
 #endif //_AER_H_
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index add9368e6314..259812620d4d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -318,6 +318,33 @@ struct pci_sriov;
 struct pci_p2pdma;
 struct rcec_ea;
 
+struct pcie_capability_regs {
+	u8 pcie_cap_id;
+	u8 next_cap_ptr;
+	u16 pcie_caps;
+	u32 device_caps;
+	u16 device_control;
+	u16 device_status;
+	u32 link_caps;
+	u16 link_control;
+	u16 link_status;
+	u32 slot_caps;
+	u16 slot_control;
+	u16 slot_status;
+	u16 root_control;
+	u16 root_caps;
+	u32 root_status;
+	u32 device_caps_2;
+	u16 device_control_2;
+	u16 device_status_2;
+	u32 link_caps_2;
+	u16 link_control_2;
+	u16 link_status_2;
+	u32 slot_caps_2;
+	u16 slot_control_2;
+	u16 slot_status_2;
+};
+
 /* The pci_dev structure describes PCI devices */
 struct pci_dev {
 	struct list_head bus_list;	/* Node in per-bus list */
-- 
2.42.0