From c100beb9ccfb98e2474586a4006483cbf770c823 Mon Sep 17 00:00:00 2001 From: Alexandru Gagniuc Date: Mon, 27 Apr 2020 18:25:13 -0500 Subject: [PATCH] PCI/AER: Use only _OSC to determine AER ownership Per the PCI Firmware spec, r3.2, sec 4.5.1, the OS can request control of AER via bit 3 of the _OSC Control Field. In the returned value of the Control Field: The firmware sets [bit 3] to 1 to grant control over PCI Express Advanced Error Reporting. ... after control is transferred to the operating system, firmware must not modify the Advanced Error Reporting Capability. If control of this feature was requested and denied or was not requested, firmware returns this bit set to 0. Previously the pci_root driver looked at the HEST FIRMWARE_FIRST bit to determine whether to request ownership of the AER Capability. This was based on ACPI spec v6.3, sec 18.3.2.4, and similar sections, which say things like: Bit [0] - FIRMWARE_FIRST: If set, indicates that system firmware will handle errors from this source first. Bit [1] - GLOBAL: If set, indicates that the settings contained in this structure apply globally to all PCI Express Devices. These ACPI references don't say anything about ownership of the AER Capability. Remove use of the FIRMWARE_FIRST bit and rely only on the _OSC bit to determine whether we have control of the AER Capability. Link: https://lore.kernel.org/r/20181115231605.24352-1-mr.nuke.me@gmail.com/ v1 Link: https://lore.kernel.org/r/20190326172343.28946-1-mr.nuke.me@gmail.com/ v2 Link: https://lore.kernel.org/r/67af2931705bed9a588b5a39d369cb70b9942190.1587925636.git.sathyanarayanan.kuppuswamy@linux.intel.com [bhelgaas: commit log, note: Alex posted this identical patch 18 months ago, and I failed to apply it then, so I made him the author, added links to his postings, and added his Signed-off-by] Signed-off-by: Alexandru Gagniuc Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Bjorn Helgaas Reviewed-by: Jon Derrick --- drivers/acpi/pci_root.c | 9 ++------- drivers/pci/pcie/aer.c | 26 +------------------------- include/linux/pci-acpi.h | 6 ------ 3 files changed, 3 insertions(+), 38 deletions(-) diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index ac8ad6cb82aa..9e235c1a75ff 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -483,13 +483,8 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm, if (IS_ENABLED(CONFIG_HOTPLUG_PCI_SHPC)) control |= OSC_PCI_SHPC_NATIVE_HP_CONTROL; - if (pci_aer_available()) { - if (aer_acpi_firmware_first()) - dev_info(&device->dev, - "PCIe AER handled by firmware\n"); - else - control |= OSC_PCI_EXPRESS_AER_CONTROL; - } + if (pci_aer_available()) + control |= OSC_PCI_EXPRESS_AER_CONTROL; /* * Per the Downstream Port Containment Related Enhancements ECN to diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c index f4274d301235..efc26773cc6d 100644 --- a/drivers/pci/pcie/aer.c +++ b/drivers/pci/pcie/aer.c @@ -318,30 +318,6 @@ int pcie_aer_get_firmware_first(struct pci_dev *dev) aer_set_firmware_first(dev); return dev->__aer_firmware_first; } - -static bool aer_firmware_first; - -/** - * aer_acpi_firmware_first - Check if APEI should control AER. - */ -bool aer_acpi_firmware_first(void) -{ - static bool parsed = false; - struct aer_hest_parse_info info = { - .pci_dev = NULL, /* Check all PCIe devices */ - .firmware_first = 0, - }; - - if (pcie_ports_native) - return false; - - if (!parsed) { - apei_hest_parse(aer_hest_parse, &info); - aer_firmware_first = info.firmware_first; - parsed = true; - } - return aer_firmware_first; -} #endif #define PCI_EXP_AER_FLAGS (PCI_EXP_DEVCTL_CERE | PCI_EXP_DEVCTL_NFERE | \ @@ -1523,7 +1499,7 @@ static struct pcie_port_service_driver aerdriver = { */ int __init pcie_aer_init(void) { - if (!pci_aer_available() || aer_acpi_firmware_first()) + if (!pci_aer_available()) return -ENXIO; return pcie_port_service_register(&aerdriver); } diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h index 2d155bfb8fbf..11c98875538a 100644 --- a/include/linux/pci-acpi.h +++ b/include/linux/pci-acpi.h @@ -125,10 +125,4 @@ static inline void acpi_pci_add_bus(struct pci_bus *bus) { } static inline void acpi_pci_remove_bus(struct pci_bus *bus) { } #endif /* CONFIG_ACPI */ -#ifdef CONFIG_ACPI_APEI -extern bool aer_acpi_firmware_first(void); -#else -static inline bool aer_acpi_firmware_first(void) { return false; } -#endif - #endif /* _PCI_ACPI_H_ */