diff options
| -rw-r--r-- | Documentation/PCI/boot-interrupts.rst | 155 | ||||
| -rw-r--r-- | Documentation/PCI/index.rst | 1 | ||||
| -rw-r--r-- | drivers/pci/quirks.c | 80 |
3 files changed, 229 insertions, 7 deletions
diff --git a/Documentation/PCI/boot-interrupts.rst b/Documentation/PCI/boot-interrupts.rst new file mode 100644 index 000000000000..d078ef3eb192 --- /dev/null +++ b/Documentation/PCI/boot-interrupts.rst @@ -0,0 +1,155 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +Boot Interrupts +=============== + +:Author: - Sean V Kelley <sean.v.kelley@linux.intel.com> + +Overview +======== + +On PCI Express, interrupts are represented with either MSI or inbound +interrupt messages (Assert_INTx/Deassert_INTx). The integrated IO-APIC in a +given Core IO converts the legacy interrupt messages from PCI Express to +MSI interrupts. If the IO-APIC is disabled (via the mask bits in the +IO-APIC table entries), the messages are routed to the legacy PCH. This +in-band interrupt mechanism was traditionally necessary for systems that +did not support the IO-APIC and for boot. Intel in the past has used the +term "boot interrupts" to describe this mechanism. Further, the PCI Express +protocol describes this in-band legacy wire-interrupt INTx mechanism for +I/O devices to signal PCI-style level interrupts. The subsequent paragraphs +describe problems with the Core IO handling of INTx message routing to the +PCH and mitigation within BIOS and the OS. + + +Issue +===== + +When in-band legacy INTx messages are forwarded to the PCH, they in turn +trigger a new interrupt for which the OS likely lacks a handler. When an +interrupt goes unhandled over time, they are tracked by the Linux kernel as +Spurious Interrupts. The IRQ will be disabled by the Linux kernel after it +reaches a specific count with the error "nobody cared". This disabled IRQ +now prevents valid usage by an existing interrupt which may happen to share +the IRQ line. + + irq 19: nobody cared (try booting with the "irqpoll" option) + CPU: 0 PID: 2988 Comm: irq/34-nipalk Tainted: 4.14.87-rt49-02410-g4a640ec-dirty #1 + Hardware name: National Instruments NI PXIe-8880/NI PXIe-8880, BIOS 2.1.5f1 01/09/2020 + Call Trace: + <IRQ> + ? dump_stack+0x46/0x5e + ? __report_bad_irq+0x2e/0xb0 + ? note_interrupt+0x242/0x290 + ? nNIKAL100_memoryRead16+0x8/0x10 [nikal] + ? handle_irq_event_percpu+0x55/0x70 + ? handle_irq_event+0x4f/0x80 + ? handle_fasteoi_irq+0x81/0x180 + ? handle_irq+0x1c/0x30 + ? do_IRQ+0x41/0xd0 + ? common_interrupt+0x84/0x84 + </IRQ> + + handlers: + irq_default_primary_handler threaded usb_hcd_irq + Disabling IRQ #19 + + +Conditions +========== + +The use of threaded interrupts is the most likely condition to trigger +this problem today. Threaded interrupts may not be reenabled after the IRQ +handler wakes. These "one shot" conditions mean that the threaded interrupt +needs to keep the interrupt line masked until the threaded handler has run. +Especially when dealing with high data rate interrupts, the thread needs to +run to completion; otherwise some handlers will end up in stack overflows +since the interrupt of the issuing device is still active. + +Affected Chipsets +================= + +The legacy interrupt forwarding mechanism exists today in a number of +devices including but not limited to chipsets from AMD/ATI, Broadcom, and +Intel. Changes made through the mitigations below have been applied to +drivers/pci/quirks.c + +Starting with ICX there are no longer any IO-APICs in the Core IO's +devices. IO-APIC is only in the PCH. Devices connected to the Core IO's +PCIe Root Ports will use native MSI/MSI-X mechanisms. + +Mitigations +=========== + +The mitigations take the form of PCI quirks. The preference has been to +first identify and make use of a means to disable the routing to the PCH. +In such a case a quirk to disable boot interrupt generation can be +added.[1] + + Intel® 6300ESB I/O Controller Hub + Alternate Base Address Register: + BIE: Boot Interrupt Enable + 0 = Boot interrupt is enabled. + 1 = Boot interrupt is disabled. + + Intel® Sandy Bridge through Sky Lake based Xeon servers: + Coherent Interface Protocol Interrupt Control + dis_intx_route2pch/dis_intx_route2ich/dis_intx_route2dmi2: + When this bit is set. Local INTx messages received from the + Intel® Quick Data DMA/PCI Express ports are not routed to legacy + PCH - they are either converted into MSI via the integrated IO-APIC + (if the IO-APIC mask bit is clear in the appropriate entries) + or cause no further action (when mask bit is set) + +In the absence of a way to directly disable the routing, another approach +has been to make use of PCI Interrupt pin to INTx routing tables for +purposes of redirecting the interrupt handler to the rerouted interrupt +line by default. Therefore, on chipsets where this INTx routing cannot be +disabled, the Linux kernel will reroute the valid interrupt to its legacy +interrupt. This redirection of the handler will prevent the occurrence of +the spurious interrupt detection which would ordinarily disable the IRQ +line due to excessive unhandled counts.[2] + +The config option X86_REROUTE_FOR_BROKEN_BOOT_IRQS exists to enable (or +disable) the redirection of the interrupt handler to the PCH interrupt +line. The option can be overridden by either pci=ioapicreroute or +pci=noioapicreroute.[3] + + +More Documentation +================== + +There is an overview of the legacy interrupt handling in several datasheets +(6300ESB and 6700PXH below). While largely the same, it provides insight +into the evolution of its handling with chipsets. + +Example of disabling of the boot interrupt +------------------------------------------ + +Intel® 6300ESB I/O Controller Hub (Document # 300641-004US) + 5.7.3 Boot Interrupt + https://www.intel.com/content/dam/doc/datasheet/6300esb-io-controller-hub-datasheet.pdf + +Intel® Xeon® Processor E5-1600/2400/2600/4600 v3 Product Families +Datasheet - Volume 2: Registers (Document # 330784-003) + 6.6.41 cipintrc Coherent Interface Protocol Interrupt Control + https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e5-v3-datasheet-vol-2.pdf + +Example of handler rerouting +---------------------------- + +Intel® 6700PXH 64-bit PCI Hub (Document # 302628) + 2.15.2 PCI Express Legacy INTx Support and Boot Interrupt + https://www.intel.com/content/dam/doc/datasheet/6700pxh-64-bit-pci-hub-datasheet.pdf + + +If you have any legacy PCI interrupt questions that aren't answered, email me. + +Cheers, + Sean V Kelley + sean.v.kelley@linux.intel.com + +[1] https://lore.kernel.org/r/12131949181903-git-send-email-sassmann@suse.de/ +[2] https://lore.kernel.org/r/12131949182094-git-send-email-sassmann@suse.de/ +[3] https://lore.kernel.org/r/487C8EA7.6020205@suse.de/ diff --git a/Documentation/PCI/index.rst b/Documentation/PCI/index.rst index 6768305e4c26..8f66feaafd4f 100644 --- a/Documentation/PCI/index.rst +++ b/Documentation/PCI/index.rst @@ -16,3 +16,4 @@ Linux PCI Bus Subsystem pci-error-recovery pcieaer-howto endpoint/index + boot-interrupts diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 29f473ebf20f..b7347bc6a24d 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -1970,26 +1970,92 @@ DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_80332_1, quirk /* * IO-APIC1 on 6300ESB generates boot interrupts, see Intel order no * 300641-004US, section 5.7.3. + * + * Core IO on Xeon E5 1600/2600/4600, see Intel order no 326509-003. + * Core IO on Xeon E5 v2, see Intel order no 329188-003. + * Core IO on Xeon E7 v2, see Intel order no 329595-002. + * Core IO on Xeon E5 v3, see Intel order no 330784-003. + * Core IO on Xeon E7 v3, see Intel order no 332315-001US. + * Core IO on Xeon E5 v4, see Intel order no 333810-002US. + * Core IO on Xeon E7 v4, see Intel order no 332315-001US. + * Core IO on Xeon D-1500, see Intel order no 332051-001. + * Core IO on Xeon Scalable, see Intel order no 610950. */ -#define INTEL_6300_IOAPIC_ABAR 0x40 +#define INTEL_6300_IOAPIC_ABAR 0x40 /* Bus 0, Dev 29, Func 5 */ #define INTEL_6300_DISABLE_BOOT_IRQ (1<<14) +#define INTEL_CIPINTRC_CFG_OFFSET 0x14C /* Bus 0, Dev 5, Func 0 */ +#define INTEL_CIPINTRC_DIS_INTX_ICH (1<<25) + static void quirk_disable_intel_boot_interrupt(struct pci_dev *dev) { u16 pci_config_word; + u32 pci_config_dword; if (noioapicquirk) return; - pci_read_config_word(dev, INTEL_6300_IOAPIC_ABAR, &pci_config_word); - pci_config_word |= INTEL_6300_DISABLE_BOOT_IRQ; - pci_write_config_word(dev, INTEL_6300_IOAPIC_ABAR, pci_config_word); - + switch (dev->device) { + case PCI_DEVICE_ID_INTEL_ESB_10: + pci_read_config_word(dev, INTEL_6300_IOAPIC_ABAR, + &pci_config_word); + pci_config_word |= INTEL_6300_DISABLE_BOOT_IRQ; + pci_write_config_word(dev, INTEL_6300_IOAPIC_ABAR, + pci_config_word); + break; + case 0x3c28: /* Xeon E5 1600/2600/4600 */ + case 0x0e28: /* Xeon E5/E7 V2 */ + case 0x2f28: /* Xeon E5/E7 V3,V4 */ + case 0x6f28: /* Xeon D-1500 */ + case 0x2034: /* Xeon Scalable Family */ + pci_read_config_dword(dev, INTEL_CIPINTRC_CFG_OFFSET, + &pci_config_dword); + pci_config_dword |= INTEL_CIPINTRC_DIS_INTX_ICH; + pci_write_config_dword(dev, INTEL_CIPINTRC_CFG_OFFSET, + pci_config_dword); + break; + default: + return; + } pci_info(dev, "disabled boot interrupts on device [%04x:%04x]\n", dev->vendor, dev->device); } -DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_10, quirk_disable_intel_boot_interrupt); -DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_10, quirk_disable_intel_boot_interrupt); +/* + * Device 29 Func 5 Device IDs of IO-APIC + * containing ABAR—APIC1 Alternate Base Address Register + */ +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_10, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_10, + quirk_disable_intel_boot_interrupt); + +/* + * Device 5 Func 0 Device IDs of Core IO modules/hubs + * containing Coherent Interface Protocol Interrupt Control + * + * Device IDs obtained from volume 2 datasheets of commented + * families above. + */ +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x3c28, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0e28, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x2f28, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x6f28, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x2034, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL, 0x3c28, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL, 0x0e28, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL, 0x2f28, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL, 0x6f28, + quirk_disable_intel_boot_interrupt); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL, 0x2034, + quirk_disable_intel_boot_interrupt); /* Disable boot interrupts on HT-1000 */ #define BC_HT1000_FEATURE_REG 0x64 |