pci: implement "pci=noaer"

For cases in which CONFIG_PCIEAER=y (such as distro kernels), allow users
to disable PCIE Advanced Error Reporting by using "pci=noaer" on the
kernel command line.

This can be used to work around hardware or (kernel) software problems.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Documentation/kernel-parameters.txt

@@ -68,6 +68,7 @@ parameter is applicable:
 	PARIDE	The ParIDE (parallel port IDE) subsystem is enabled.
 	PARISC	The PA-RISC architecture is enabled.
 	PCI	PCI bus support is enabled.
+	PCIE	PCI Express support is enabled.
 	PCMCIA	The PCMCIA subsystem is enabled.
 	PNP	Plug & Play support is enabled.
 	PPC	PowerPC architecture is enabled.
@@ -1270,6 +1271,9 @@ and is between 256 and 4096 characters. It is defined in the file
 				Mechanism 1.
 		conf2		[X86-32] Force use of PCI Configuration
 				Mechanism 2.
+		noaer		[PCIE] If the PCIEAER kernel config parameter is
+				enabled, this kernel boot option can be used to
+				disable the use of PCIE advanced error reporting.
 		nommconf	[X86-32,X86_64] Disable use of MMCONFIG for PCI
 				Configuration
 		nomsi		[MSI] If the PCI_MSI kernel config parameter is

drivers/pci/pci.c

@@ -1586,6 +1586,8 @@ static int __devinit pci_setup(char *str)
 		if (*str && (str = pcibios_setup(str)) && *str) {
 			if (!strcmp(str, "nomsi")) {
 				pci_no_msi();
+			} else if (!strcmp(str, "noaer")) {
+				pci_no_aer();
 			} else if (!strncmp(str, "cbiosize=", 9)) {
 				pci_cardbus_io_size = memparse(str + 9, &str);
 			} else if (!strncmp(str, "cbmemsize=", 10)) {

drivers/pci/pci.h

@@ -52,6 +52,12 @@ void pci_restore_msi_state(struct pci_dev *dev);
 static inline void pci_restore_msi_state(struct pci_dev *dev) {}
 #endif
 
+#ifdef CONFIG_PCIEAER
+void pci_no_aer(void);
+#else
+static inline void pci_no_aer(void) { }
+#endif
+
 static inline int pci_no_d1d2(struct pci_dev *dev)
 {
 	unsigned int parent_dstates = 0;

drivers/pci/pcie/aer/aerdrv.c

@@ -81,6 +81,13 @@ static struct pcie_port_service_driver aerdriver = {
 	.reset_link	= aer_root_reset,
 };
 
+static int pcie_aer_disable;
+
+void pci_no_aer(void)
+{
+	pcie_aer_disable = 1;	/* has priority over 'forceload' */
+}
+
 /**
  * aer_irq - Root Port's ISR
  * @irq: IRQ assigned to Root Port
@@ -327,6 +334,8 @@ static void aer_error_resume(struct pci_dev *dev)
  **/
 static int __init aer_service_init(void)
 {
+	if (pcie_aer_disable)
+		return -ENXIO;
 	return pcie_port_service_register(&aerdriver);
 }