Merge branch 'for-6.3/cxl' into cxl/next

Merge the general CXL updates with fixes targeting v6.2-rc for v6.3.
Resolve a conflict with the fix and move of cxl_report_and_clear() from
pci.c to core/pci.c.

Author: djbw

Documentation/ABI/testing/sysfs-bus-cxl

@@ -90,6 +90,21 @@ Description:
 		capability.
 
 
+What:		/sys/bus/cxl/devices/{port,endpoint}X/parent_dport
+Date:		January, 2023
+KernelVersion:	v6.3
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) CXL port objects are instantiated for each upstream port in
+		a CXL/PCIe switch, and for each endpoint to map the
+		corresponding memory device into the CXL port hierarchy. When a
+		descendant CXL port (switch or endpoint) is enumerated it is
+		useful to know which 'dport' object in the parent CXL port
+		routes to this descendant. The 'parent_dport' symlink points to
+		the device representing the downstream port of a CXL switch that
+		routes to {port,endpoint}X.
+
+
 What:		/sys/bus/cxl/devices/portX/dportY
 Date:		June, 2021
 KernelVersion:	v5.14

drivers/acpi/pci_root.c

@@ -1047,6 +1047,9 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 	if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
 		host_bridge->native_dpc = 0;
 
+	if (!(root->osc_ext_control_set & OSC_CXL_ERROR_REPORTING_CONTROL))
+		host_bridge->native_cxl_error = 0;
+
 	/*
 	 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it
 	 * exists and returns 0, we must preserve any PCI resource

drivers/cxl/Kconfig

@@ -116,7 +116,7 @@ config CXL_REGION_INVALIDATION_TEST
 	depends on CXL_REGION
 	help
 	  CXL Region management and security operations potentially invalidate
-	  the content of CPU caches without notifiying those caches to
+	  the content of CPU caches without notifying those caches to
 	  invalidate the affected cachelines. The CXL Region driver attempts
 	  to invalidate caches when those events occur.  If that invalidation
 	  fails the region will fail to enable.  Reasons for cache

drivers/cxl/acpi.c

@@ -19,7 +19,7 @@ struct cxl_cxims_data {
 
 /*
  * Find a targets entry (n) in the host bridge interleave list.
- * CXL Specfication 3.0 Table 9-22
+ * CXL Specification 3.0 Table 9-22
  */
 static int cxl_xor_calc_n(u64 hpa, struct cxl_cxims_data *cximsd, int iw,
 			  int ig)

drivers/cxl/core/Makefile

@@ -3,11 +3,14 @@ obj-$(CONFIG_CXL_BUS) += cxl_core.o
 obj-$(CONFIG_CXL_SUSPEND) += suspend.o
 
 ccflags-y += -I$(srctree)/drivers/cxl
+CFLAGS_trace.o = -DTRACE_INCLUDE_PATH=. -I$(src)
+
 cxl_core-y := port.o
 cxl_core-y += pmem.o
 cxl_core-y += regs.o
 cxl_core-y += memdev.o
 cxl_core-y += mbox.o
 cxl_core-y += pci.o
 cxl_core-y += hdm.o
+cxl_core-$(CONFIG_TRACING) += trace.o
 cxl_core-$(CONFIG_CXL_REGION) += region.o

drivers/cxl/core/mbox.c

@@ -170,6 +170,12 @@ int cxl_internal_send_cmd(struct cxl_dev_state *cxlds,
 	out_size = mbox_cmd->size_out;
 	min_out = mbox_cmd->min_out;
 	rc = cxlds->mbox_send(cxlds, mbox_cmd);
+	/*
+	 * EIO is reserved for a payload size mismatch and mbox_send()
+	 * may not return this error.
+	 */
+	if (WARN_ONCE(rc == -EIO, "Bad return code: -EIO"))
+		return -ENXIO;
 	if (rc)
 		return rc;
 
@@ -550,9 +556,9 @@ int cxl_send_cmd(struct cxl_memdev *cxlmd, struct cxl_send_command __user *s)
 	return 0;
 }
 
-static int cxl_xfer_log(struct cxl_dev_state *cxlds, uuid_t *uuid, u32 size, u8 *out)
+static int cxl_xfer_log(struct cxl_dev_state *cxlds, uuid_t *uuid, u32 *size, u8 *out)
 {
-	u32 remaining = size;
+	u32 remaining = *size;
 	u32 offset = 0;
 
 	while (remaining) {
@@ -576,6 +582,17 @@ static int cxl_xfer_log(struct cxl_dev_state *cxlds, uuid_t *uuid, u32 size, u8
 		};
 
 		rc = cxl_internal_send_cmd(cxlds, &mbox_cmd);
+
+		/*
+		 * The output payload length that indicates the number
+		 * of valid bytes can be smaller than the Log buffer
+		 * size.
+		 */
+		if (rc == -EIO && mbox_cmd.size_out < xfer_size) {
+			offset += mbox_cmd.size_out;
+			break;
+		}
+
 		if (rc < 0)
 			return rc;
 
@@ -584,6 +601,8 @@ static int cxl_xfer_log(struct cxl_dev_state *cxlds, uuid_t *uuid, u32 size, u8
 		offset += xfer_size;
 	}
 
+	*size = offset;
+
 	return 0;
 }
 
@@ -610,11 +629,12 @@ static void cxl_walk_cel(struct cxl_dev_state *cxlds, size_t size, u8 *cel)
 
 		if (!cmd) {
 			dev_dbg(cxlds->dev,
-				"Opcode 0x%04x unsupported by driver", opcode);
+				"Opcode 0x%04x unsupported by driver\n", opcode);
 			continue;
 		}
 
 		set_bit(cmd->info.id, cxlds->enabled_cmds);
+		dev_dbg(cxlds->dev, "Opcode 0x%04x enabled\n", opcode);
 	}
 }
 
@@ -694,7 +714,7 @@ int cxl_enumerate_cmds(struct cxl_dev_state *cxlds)
 			goto out;
 		}
 
-		rc = cxl_xfer_log(cxlds, &uuid, size, log);
+		rc = cxl_xfer_log(cxlds, &uuid, &size, log);
 		if (rc) {
 			kvfree(log);
 			goto out;

drivers/cxl/core/pci.c

@@ -9,6 +9,7 @@
 #include <cxlmem.h>
 #include <cxl.h>
 #include "core.h"
+#include "trace.h"
 
 /**
  * DOC: cxl core pci
@@ -622,3 +623,117 @@ void read_cdat_data(struct cxl_port *port)
 	}
 }
 EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
+
+void cxl_cor_error_detected(struct pci_dev *pdev)
+{
+	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
+	struct cxl_memdev *cxlmd = cxlds->cxlmd;
+	struct device *dev = &cxlmd->dev;
+	void __iomem *addr;
+	u32 status;
+
+	if (!cxlds->regs.ras)
+		return;
+
+	addr = cxlds->regs.ras + CXL_RAS_CORRECTABLE_STATUS_OFFSET;
+	status = readl(addr);
+	if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) {
+		writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, addr);
+		trace_cxl_aer_correctable_error(dev, status);
+	}
+}
+EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, CXL);
+
+/* CXL spec rev3.0 8.2.4.16.1 */
+static void header_log_copy(struct cxl_dev_state *cxlds, u32 *log)
+{
+	void __iomem *addr;
+	u32 *log_addr;
+	int i, log_u32_size = CXL_HEADERLOG_SIZE / sizeof(u32);
+
+	addr = cxlds->regs.ras + CXL_RAS_HEADER_LOG_OFFSET;
+	log_addr = log;
+
+	for (i = 0; i < log_u32_size; i++) {
+		*log_addr = readl(addr);
+		log_addr++;
+		addr += sizeof(u32);
+	}
+}
+
+/*
+ * Log the state of the RAS status registers and prepare them to log the
+ * next error status. Return 1 if reset needed.
+ */
+static bool cxl_report_and_clear(struct cxl_dev_state *cxlds)
+{
+	struct cxl_memdev *cxlmd = cxlds->cxlmd;
+	struct device *dev = &cxlmd->dev;
+	u32 hl[CXL_HEADERLOG_SIZE_U32];
+	void __iomem *addr;
+	u32 status;
+	u32 fe;
+
+	if (!cxlds->regs.ras)
+		return false;
+
+	addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET;
+	status = readl(addr);
+	if (!(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK))
+		return false;
+
+	/* If multiple errors, log header points to first error from ctrl reg */
+	if (hweight32(status) > 1) {
+		void __iomem *rcc_addr =
+			cxlds->regs.ras + CXL_RAS_CAP_CONTROL_OFFSET;
+
+		fe = BIT(FIELD_GET(CXL_RAS_CAP_CONTROL_FE_MASK,
+				   readl(rcc_addr)));
+	} else {
+		fe = status;
+	}
+
+	header_log_copy(cxlds, hl);
+	trace_cxl_aer_uncorrectable_error(dev, status, fe, hl);
+	writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, addr);
+
+	return true;
+}
+
+pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
+				    pci_channel_state_t state)
+{
+	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
+	struct cxl_memdev *cxlmd = cxlds->cxlmd;
+	struct device *dev = &cxlmd->dev;
+	bool ue;
+
+	/*
+	 * A frozen channel indicates an impending reset which is fatal to
+	 * CXL.mem operation, and will likely crash the system. On the off
+	 * chance the situation is recoverable dump the status of the RAS
+	 * capability registers and bounce the active state of the memdev.
+	 */
+	ue = cxl_report_and_clear(cxlds);
+
+	switch (state) {
+	case pci_channel_io_normal:
+		if (ue) {
+			device_release_driver(dev);
+			return PCI_ERS_RESULT_NEED_RESET;
+		}
+		return PCI_ERS_RESULT_CAN_RECOVER;
+	case pci_channel_io_frozen:
+		dev_warn(&pdev->dev,
+			 "%s: frozen state error detected, disable CXL.mem\n",
+			 dev_name(dev));
+		device_release_driver(dev);
+		return PCI_ERS_RESULT_NEED_RESET;
+	case pci_channel_io_perm_failure:
+		dev_warn(&pdev->dev,
+			 "failure state error detected, request disconnect\n");
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_error_detected, CXL);

drivers/cxl/core/port.c

@@ -583,6 +583,29 @@ static int devm_cxl_link_uport(struct device *host, struct cxl_port *port)
 	return devm_add_action_or_reset(host, cxl_unlink_uport, port);
 }
 
+static void cxl_unlink_parent_dport(void *_port)
+{
+	struct cxl_port *port = _port;
+
+	sysfs_remove_link(&port->dev.kobj, "parent_dport");
+}
+
+static int devm_cxl_link_parent_dport(struct device *host,
+				      struct cxl_port *port,
+				      struct cxl_dport *parent_dport)
+{
+	int rc;
+
+	if (!parent_dport)
+		return 0;
+
+	rc = sysfs_create_link(&port->dev.kobj, &parent_dport->dport->kobj,
+			       "parent_dport");
+	if (rc)
+		return rc;
+	return devm_add_action_or_reset(host, cxl_unlink_parent_dport, port);
+}
+
 static struct lock_class_key cxl_port_key;
 
 static struct cxl_port *cxl_port_alloc(struct device *uport,
@@ -692,6 +715,10 @@ static struct cxl_port *__devm_cxl_add_port(struct device *host,
 	if (rc)
 		return ERR_PTR(rc);
 
+	rc = devm_cxl_link_parent_dport(host, port, parent_dport);
+	if (rc)
+		return ERR_PTR(rc);
+
 	return port;
 
 err:
@@ -1137,7 +1164,7 @@ static struct cxl_port *find_cxl_port_at(struct cxl_port *parent_port,
 }
 
 /*
- * All users of grandparent() are using it to walk PCIe-like swich port
+ * All users of grandparent() are using it to walk PCIe-like switch port
  * hierarchy. A PCIe switch is comprised of a bridge device representing the
  * upstream switch port and N bridges representing downstream switch ports. When
  * bridges stack the grand-parent of a downstream switch port is another
@@ -1164,6 +1191,7 @@ static void delete_endpoint(void *data)
 
 	device_lock(parent);
 	if (parent->driver && !endpoint->dead) {
+		devm_release_action(parent, cxl_unlink_parent_dport, endpoint);
 		devm_release_action(parent, cxl_unlink_uport, endpoint);
 		devm_release_action(parent, unregister_port, endpoint);
 	}
@@ -1194,6 +1222,7 @@ EXPORT_SYMBOL_NS_GPL(cxl_endpoint_autoremove, CXL);
  */
 static void delete_switch_port(struct cxl_port *port)
 {
+	devm_release_action(port->dev.parent, cxl_unlink_parent_dport, port);
 	devm_release_action(port->dev.parent, cxl_unlink_uport, port);
 	devm_release_action(port->dev.parent, unregister_port, port);
 }

drivers/cxl/core/region.c

@@ -157,6 +157,22 @@ static int cxl_region_decode_reset(struct cxl_region *cxlr, int count)
 	return 0;
 }
 
+static int commit_decoder(struct cxl_decoder *cxld)
+{
+	struct cxl_switch_decoder *cxlsd = NULL;
+
+	if (cxld->commit)
+		return cxld->commit(cxld);
+
+	if (is_switch_decoder(&cxld->dev))
+		cxlsd = to_cxl_switch_decoder(&cxld->dev);
+
+	if (dev_WARN_ONCE(&cxld->dev, !cxlsd || cxlsd->nr_targets > 1,
+			  "->commit() is required\n"))
+		return -ENXIO;
+	return 0;
+}
+
 static int cxl_region_decode_commit(struct cxl_region *cxlr)
 {
 	struct cxl_region_params *p = &cxlr->params;
@@ -175,8 +191,7 @@ static int cxl_region_decode_commit(struct cxl_region *cxlr)
 		     iter = to_cxl_port(iter->dev.parent)) {
 			cxl_rr = cxl_rr_load(iter, cxlr);
 			cxld = cxl_rr->decoder;
-			if (cxld->commit)
-				rc = cxld->commit(cxld);
+			rc = commit_decoder(cxld);
 			if (rc)
 				break;
 		}
@@ -401,7 +416,7 @@ static ssize_t interleave_granularity_store(struct device *dev,
 	 * When the host-bridge is interleaved, disallow region granularity !=
 	 * root granularity. Regions with a granularity less than the root
 	 * interleave result in needing multiple endpoints to support a single
-	 * slot in the interleave (possible to suport in the future). Regions
+	 * slot in the interleave (possible to support in the future). Regions
 	 * with a granularity greater than the root interleave result in invalid
 	 * DPA translations (invalid to support).
 	 */
@@ -1969,7 +1984,7 @@ static int cxl_region_invalidate_memregion(struct cxl_region *cxlr)
 
 	if (!cpu_cache_has_invalidate_memregion()) {
 		if (IS_ENABLED(CONFIG_CXL_REGION_INVALIDATION_TEST)) {
-			dev_warn(
+			dev_warn_once(
 				&cxlr->dev,
 				"Bypassing cpu_cache_invalidate_memregion() for testing!\n");
 			clear_bit(CXL_REGION_F_INCOHERENT, &cxlr->flags);

drivers/cxl/core/trace.c

@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"