linux-kernel - [PATCH v2 2/3] cxl/pci: Process CPER events

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Date: Mon, 22 Apr 2024 15:25:46 -0700
From: Ira Weiny <ira.weiny@...el.com>
To: Dave Jiang <dave.jiang@...el.com>, 
 Dan Williams <dan.j.williams@...el.com>, 
 Jonathan Cameron <jonathan.cameron@...wei.com>, 
 Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>, 
 Shiju Jose <shiju.jose@...wei.com>
Cc: Dan Carpenter <dan.carpenter@...aro.org>, 
 Yazen Ghannam <yazen.ghannam@....com>, Davidlohr Bueso <dave@...olabs.net>, 
 Alison Schofield <alison.schofield@...el.com>, 
 Vishal Verma <vishal.l.verma@...el.com>, Ard Biesheuvel <ardb@...nel.org>, 
 linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-cxl@...r.kernel.org, Ira Weiny <ira.weiny@...el.com>
Subject: [PATCH v2 2/3] cxl/pci: Process CPER events

If the firmware has configured CXL event support to be firmware first
the OS will receive those events through CPER records.  The CXL layer has
unique DPA to HPA knowledge and existing event trace parsing in
place.[0]

Add a CXL CPER callback to process CPER events.

[0]
Link: https://lore.kernel.org/all/cover.1711598777.git.alison.schofield@intel.com/

Signed-off-by: Ira Weiny <ira.weiny@...el.com>

---
Changes:
[djbw: Clean up error and debug messages]
[iweiny: Clean up commit message]
[iweiny: Add back in after the revert in 6.8]
---
 drivers/cxl/pci.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 2ff361e756d6..c0bc2e994a90 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -974,6 +974,65 @@ static struct pci_driver cxl_pci_driver = {
 	},
 };
 
-module_pci_driver(cxl_pci_driver);
+#define CXL_EVENT_HDR_FLAGS_REC_SEVERITY GENMASK(1, 0)
+static void cxl_cper_event_call(enum cxl_event_type ev_type,
+				struct cxl_cper_event_rec *rec)
+{
+	struct cper_cxl_event_devid *device_id = &rec->hdr.device_id;
+	struct pci_dev *pdev __free(pci_dev_put) = NULL;
+	enum cxl_event_log_type log_type;
+	struct cxl_dev_state *cxlds;
+	unsigned int devfn;
+	u32 hdr_flags;
+
+	pr_debug("CPER event %d for device %u:%u:%u.%u\n", ev_type,
+		 device_id->segment_num, device_id->bus_num,
+		 device_id->device_num, device_id->func_num);
+
+	devfn = PCI_DEVFN(device_id->device_num, device_id->func_num);
+	pdev = pci_get_domain_bus_and_slot(device_id->segment_num,
+					   device_id->bus_num, devfn);
+	if (!pdev)
+		return;
+
+	guard(device)(&pdev->dev);
+	if (pdev->driver != &cxl_pci_driver)
+		return;
+
+	cxlds = pci_get_drvdata(pdev);
+	if (!cxlds)
+		return;
+
+	/* Fabricate a log type */
+	hdr_flags = get_unaligned_le24(rec->event.generic.hdr.flags);
+	log_type = FIELD_GET(CXL_EVENT_HDR_FLAGS_REC_SEVERITY, hdr_flags);
+
+	cxl_event_trace_record(cxlds->cxlmd, log_type, ev_type,
+			       &uuid_null, &rec->event);
+}
+
+static int __init cxl_pci_driver_init(void)
+{
+	int rc;
+
+	rc = pci_register_driver(&cxl_pci_driver);
+	if (rc)
+		return rc;
+
+	rc = cxl_cper_register_callback(cxl_cper_event_call);
+	if (rc)
+		pci_unregister_driver(&cxl_pci_driver);
+
+	return rc;
+}
+
+static void __exit cxl_pci_driver_exit(void)
+{
+	cxl_cper_unregister_callback(cxl_cper_event_call);
+	pci_unregister_driver(&cxl_pci_driver);
+}
+
+module_init(cxl_pci_driver_init);
+module_exit(cxl_pci_driver_exit);
 MODULE_LICENSE("GPL v2");
 MODULE_IMPORT_NS(CXL);

-- 
2.44.0