PCI/AER: Export pci_aer_unmask_internal_errors()

Internal PCIe errors are not enabled by default during initialization
because their behavior is too device-specific and there is no standard way
to reason about them. However, for CXL an internal error is the standard
mechanism for conveying CXL protocol errors.

Export pci_aer_unmask_internal_errors() for CXL, but make it clear that
they are only meant for CXL and the status quo for leaving them masked for
PCIe in general remains.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20260114182055.46029-10-terry.bowman@amd.com
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Author: ktbowman

drivers/pci/pcie/aer.c

@@ -1120,8 +1120,6 @@ static bool find_source_device(struct pci_dev *parent,
 	return true;
 }
 
-#ifdef CONFIG_PCIEAER_CXL
-
 /**
  * pci_aer_unmask_internal_errors - unmask internal errors
  * @dev: pointer to the pci_dev data structure
@@ -1132,7 +1130,7 @@ static bool find_source_device(struct pci_dev *parent,
  * Note: AER must be enabled and supported by the device which must be
  * checked in advance, e.g. with pcie_aer_is_native().
  */
-static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
+void pci_aer_unmask_internal_errors(struct pci_dev *dev)
 {
 	int aer = dev->aer_cap;
 	u32 mask;
@@ -1146,6 +1144,13 @@ static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
 	pci_write_config_dword(dev, aer + PCI_ERR_COR_MASK, mask);
 }
 
+/*
+ * Internal errors are too device-specific to enable generally, however for CXL
+ * their behavior is standardized for conveying CXL protocol errors.
+ */
+EXPORT_SYMBOL_FOR_MODULES(pci_aer_unmask_internal_errors, "cxl_core");
+
+#ifdef CONFIG_PCIEAER_CXL
 static bool is_cxl_mem_dev(struct pci_dev *dev)
 {
 	/*

include/linux/aer.h

@@ -56,12 +56,14 @@ struct aer_capability_regs {
 #if defined(CONFIG_PCIEAER)
 int pci_aer_clear_nonfatal_status(struct pci_dev *dev);
 int pcie_aer_is_native(struct pci_dev *dev);
+void pci_aer_unmask_internal_errors(struct pci_dev *dev);
 #else
 static inline int pci_aer_clear_nonfatal_status(struct pci_dev *dev)
 {
 	return -EINVAL;
 }
 static inline int pcie_aer_is_native(struct pci_dev *dev) { return 0; }
+static inline void pci_aer_unmask_internal_errors(struct pci_dev *dev) { }
 #endif
 
 void pci_print_aer(struct pci_dev *dev, int aer_severity,