| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright IBM Corp. 2012 |
| * |
| * Author(s): |
| * Jan Glauber <jang@linux.vnet.ibm.com> |
| */ |
| |
| #define KMSG_COMPONENT "zpci" |
| #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/pci.h> |
| #include <asm/pci_debug.h> |
| #include <asm/pci_dma.h> |
| #include <asm/sclp.h> |
| |
| #include "pci_bus.h" |
| |
| /* Content Code Description for PCI Function Error */ |
| struct zpci_ccdf_err { |
| u32 reserved1; |
| u32 fh; /* function handle */ |
| u32 fid; /* function id */ |
| u32 ett : 4; /* expected table type */ |
| u32 mvn : 12; /* MSI vector number */ |
| u32 dmaas : 8; /* DMA address space */ |
| u32 : 6; |
| u32 q : 1; /* event qualifier */ |
| u32 rw : 1; /* read/write */ |
| u64 faddr; /* failing address */ |
| u32 reserved3; |
| u16 reserved4; |
| u16 pec; /* PCI event code */ |
| } __packed; |
| |
| /* Content Code Description for PCI Function Availability */ |
| struct zpci_ccdf_avail { |
| u32 reserved1; |
| u32 fh; /* function handle */ |
| u32 fid; /* function id */ |
| u32 reserved2; |
| u32 reserved3; |
| u32 reserved4; |
| u32 reserved5; |
| u16 reserved6; |
| u16 pec; /* PCI event code */ |
| } __packed; |
| |
| static inline bool ers_result_indicates_abort(pci_ers_result_t ers_res) |
| { |
| switch (ers_res) { |
| case PCI_ERS_RESULT_CAN_RECOVER: |
| case PCI_ERS_RESULT_RECOVERED: |
| case PCI_ERS_RESULT_NEED_RESET: |
| return false; |
| default: |
| return true; |
| } |
| } |
| |
| static bool is_passed_through(struct pci_dev *pdev) |
| { |
| struct zpci_dev *zdev = to_zpci(pdev); |
| bool ret; |
| |
| mutex_lock(&zdev->kzdev_lock); |
| ret = !!zdev->kzdev; |
| mutex_unlock(&zdev->kzdev_lock); |
| |
| return ret; |
| } |
| |
| static bool is_driver_supported(struct pci_driver *driver) |
| { |
| if (!driver || !driver->err_handler) |
| return false; |
| if (!driver->err_handler->error_detected) |
| return false; |
| if (!driver->err_handler->slot_reset) |
| return false; |
| if (!driver->err_handler->resume) |
| return false; |
| return true; |
| } |
| |
| static pci_ers_result_t zpci_event_notify_error_detected(struct pci_dev *pdev, |
| struct pci_driver *driver) |
| { |
| pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT; |
| |
| ers_res = driver->err_handler->error_detected(pdev, pdev->error_state); |
| if (ers_result_indicates_abort(ers_res)) |
| pr_info("%s: Automatic recovery failed after initial reporting\n", pci_name(pdev)); |
| else if (ers_res == PCI_ERS_RESULT_NEED_RESET) |
| pr_debug("%s: Driver needs reset to recover\n", pci_name(pdev)); |
| |
| return ers_res; |
| } |
| |
| static pci_ers_result_t zpci_event_do_error_state_clear(struct pci_dev *pdev, |
| struct pci_driver *driver) |
| { |
| pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT; |
| struct zpci_dev *zdev = to_zpci(pdev); |
| int rc; |
| |
| pr_info("%s: Unblocking device access for examination\n", pci_name(pdev)); |
| rc = zpci_reset_load_store_blocked(zdev); |
| if (rc) { |
| pr_err("%s: Unblocking device access failed\n", pci_name(pdev)); |
| /* Let's try a full reset instead */ |
| return PCI_ERS_RESULT_NEED_RESET; |
| } |
| |
| if (driver->err_handler->mmio_enabled) { |
| ers_res = driver->err_handler->mmio_enabled(pdev); |
| if (ers_result_indicates_abort(ers_res)) { |
| pr_info("%s: Automatic recovery failed after MMIO re-enable\n", |
| pci_name(pdev)); |
| return ers_res; |
| } else if (ers_res == PCI_ERS_RESULT_NEED_RESET) { |
| pr_debug("%s: Driver needs reset to recover\n", pci_name(pdev)); |
| return ers_res; |
| } |
| } |
| |
| pr_debug("%s: Unblocking DMA\n", pci_name(pdev)); |
| rc = zpci_clear_error_state(zdev); |
| if (!rc) { |
| pdev->error_state = pci_channel_io_normal; |
| } else { |
| pr_err("%s: Unblocking DMA failed\n", pci_name(pdev)); |
| /* Let's try a full reset instead */ |
| return PCI_ERS_RESULT_NEED_RESET; |
| } |
| |
| return ers_res; |
| } |
| |
| static pci_ers_result_t zpci_event_do_reset(struct pci_dev *pdev, |
| struct pci_driver *driver) |
| { |
| pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT; |
| |
| pr_info("%s: Initiating reset\n", pci_name(pdev)); |
| if (zpci_hot_reset_device(to_zpci(pdev))) { |
| pr_err("%s: The reset request failed\n", pci_name(pdev)); |
| return ers_res; |
| } |
| pdev->error_state = pci_channel_io_normal; |
| ers_res = driver->err_handler->slot_reset(pdev); |
| if (ers_result_indicates_abort(ers_res)) { |
| pr_info("%s: Automatic recovery failed after slot reset\n", pci_name(pdev)); |
| return ers_res; |
| } |
| |
| return ers_res; |
| } |
| |
| /* zpci_event_attempt_error_recovery - Try to recover the given PCI function |
| * @pdev: PCI function to recover currently in the error state |
| * |
| * We follow the scheme outlined in Documentation/PCI/pci-error-recovery.rst. |
| * With the simplification that recovery always happens per function |
| * and the platform determines which functions are affected for |
| * multi-function devices. |
| */ |
| static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev) |
| { |
| pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT; |
| struct pci_driver *driver; |
| |
| /* |
| * Ensure that the PCI function is not removed concurrently, no driver |
| * is unbound or probed and that userspace can't access its |
| * configuration space while we perform recovery. |
| */ |
| pci_dev_lock(pdev); |
| if (pdev->error_state == pci_channel_io_perm_failure) { |
| ers_res = PCI_ERS_RESULT_DISCONNECT; |
| goto out_unlock; |
| } |
| pdev->error_state = pci_channel_io_frozen; |
| |
| if (is_passed_through(pdev)) { |
| pr_info("%s: Cannot be recovered in the host because it is a pass-through device\n", |
| pci_name(pdev)); |
| goto out_unlock; |
| } |
| |
| driver = to_pci_driver(pdev->dev.driver); |
| if (!is_driver_supported(driver)) { |
| if (!driver) |
| pr_info("%s: Cannot be recovered because no driver is bound to the device\n", |
| pci_name(pdev)); |
| else |
| pr_info("%s: The %s driver bound to the device does not support error recovery\n", |
| pci_name(pdev), |
| driver->name); |
| goto out_unlock; |
| } |
| |
| ers_res = zpci_event_notify_error_detected(pdev, driver); |
| if (ers_result_indicates_abort(ers_res)) |
| goto out_unlock; |
| |
| if (ers_res == PCI_ERS_RESULT_CAN_RECOVER) { |
| ers_res = zpci_event_do_error_state_clear(pdev, driver); |
| if (ers_result_indicates_abort(ers_res)) |
| goto out_unlock; |
| } |
| |
| if (ers_res == PCI_ERS_RESULT_NEED_RESET) |
| ers_res = zpci_event_do_reset(pdev, driver); |
| |
| if (ers_res != PCI_ERS_RESULT_RECOVERED) { |
| pr_err("%s: Automatic recovery failed; operator intervention is required\n", |
| pci_name(pdev)); |
| goto out_unlock; |
| } |
| |
| pr_info("%s: The device is ready to resume operations\n", pci_name(pdev)); |
| if (driver->err_handler->resume) |
| driver->err_handler->resume(pdev); |
| out_unlock: |
| pci_dev_unlock(pdev); |
| |
| return ers_res; |
| } |
| |
| /* zpci_event_io_failure - Report PCI channel failure state to driver |
| * @pdev: PCI function for which to report |
| * @es: PCI channel failure state to report |
| */ |
| static void zpci_event_io_failure(struct pci_dev *pdev, pci_channel_state_t es) |
| { |
| struct pci_driver *driver; |
| |
| pci_dev_lock(pdev); |
| pdev->error_state = es; |
| /** |
| * While vfio-pci's error_detected callback notifies user-space QEMU |
| * reacts to this by freezing the guest. In an s390 environment PCI |
| * errors are rarely fatal so this is overkill. Instead in the future |
| * we will inject the error event and let the guest recover the device |
| * itself. |
| */ |
| if (is_passed_through(pdev)) |
| goto out; |
| driver = to_pci_driver(pdev->dev.driver); |
| if (driver && driver->err_handler && driver->err_handler->error_detected) |
| driver->err_handler->error_detected(pdev, pdev->error_state); |
| out: |
| pci_dev_unlock(pdev); |
| } |
| |
| static void __zpci_event_error(struct zpci_ccdf_err *ccdf) |
| { |
| struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid); |
| struct pci_dev *pdev = NULL; |
| pci_ers_result_t ers_res; |
| |
| zpci_dbg(3, "err fid:%x, fh:%x, pec:%x\n", |
| ccdf->fid, ccdf->fh, ccdf->pec); |
| zpci_err("error CCDF:\n"); |
| zpci_err_hex(ccdf, sizeof(*ccdf)); |
| |
| if (zdev) { |
| mutex_lock(&zdev->state_lock); |
| zpci_update_fh(zdev, ccdf->fh); |
| if (zdev->zbus->bus) |
| pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn); |
| } |
| |
| pr_err("%s: Event 0x%x reports an error for PCI function 0x%x\n", |
| pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid); |
| |
| if (!pdev) |
| goto no_pdev; |
| |
| switch (ccdf->pec) { |
| case 0x002a: /* Error event concerns FMB */ |
| case 0x002b: |
| case 0x002c: |
| break; |
| case 0x0040: /* Service Action or Error Recovery Failed */ |
| case 0x003b: |
| zpci_event_io_failure(pdev, pci_channel_io_perm_failure); |
| break; |
| default: /* PCI function left in the error state attempt to recover */ |
| ers_res = zpci_event_attempt_error_recovery(pdev); |
| if (ers_res != PCI_ERS_RESULT_RECOVERED) |
| zpci_event_io_failure(pdev, pci_channel_io_perm_failure); |
| break; |
| } |
| pci_dev_put(pdev); |
| no_pdev: |
| if (zdev) |
| mutex_unlock(&zdev->state_lock); |
| zpci_zdev_put(zdev); |
| } |
| |
| void zpci_event_error(void *data) |
| { |
| if (zpci_is_enabled()) |
| __zpci_event_error(data); |
| } |
| |
| static void zpci_event_hard_deconfigured(struct zpci_dev *zdev, u32 fh) |
| { |
| zpci_update_fh(zdev, fh); |
| /* Give the driver a hint that the function is |
| * already unusable. |
| */ |
| zpci_bus_remove_device(zdev, true); |
| /* Even though the device is already gone we still |
| * need to free zPCI resources as part of the disable. |
| */ |
| if (zdev_enabled(zdev)) |
| zpci_disable_device(zdev); |
| zdev->state = ZPCI_FN_STATE_STANDBY; |
| } |
| |
| static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf) |
| { |
| struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid); |
| bool existing_zdev = !!zdev; |
| enum zpci_state state; |
| |
| zpci_dbg(3, "avl fid:%x, fh:%x, pec:%x\n", |
| ccdf->fid, ccdf->fh, ccdf->pec); |
| |
| if (existing_zdev) |
| mutex_lock(&zdev->state_lock); |
| |
| switch (ccdf->pec) { |
| case 0x0301: /* Reserved|Standby -> Configured */ |
| if (!zdev) { |
| zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_CONFIGURED); |
| if (IS_ERR(zdev)) |
| break; |
| } else { |
| /* the configuration request may be stale */ |
| if (zdev->state != ZPCI_FN_STATE_STANDBY) |
| break; |
| zdev->state = ZPCI_FN_STATE_CONFIGURED; |
| } |
| zpci_scan_configured_device(zdev, ccdf->fh); |
| break; |
| case 0x0302: /* Reserved -> Standby */ |
| if (!zdev) |
| zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_STANDBY); |
| else |
| zpci_update_fh(zdev, ccdf->fh); |
| break; |
| case 0x0303: /* Deconfiguration requested */ |
| if (zdev) { |
| /* The event may have been queued before we configured |
| * the device. |
| */ |
| if (zdev->state != ZPCI_FN_STATE_CONFIGURED) |
| break; |
| zpci_update_fh(zdev, ccdf->fh); |
| zpci_deconfigure_device(zdev); |
| } |
| break; |
| case 0x0304: /* Configured -> Standby|Reserved */ |
| if (zdev) { |
| /* The event may have been queued before we configured |
| * the device.: |
| */ |
| if (zdev->state == ZPCI_FN_STATE_CONFIGURED) |
| zpci_event_hard_deconfigured(zdev, ccdf->fh); |
| /* The 0x0304 event may immediately reserve the device */ |
| if (!clp_get_state(zdev->fid, &state) && |
| state == ZPCI_FN_STATE_RESERVED) { |
| zpci_device_reserved(zdev); |
| } |
| } |
| break; |
| case 0x0306: /* 0x308 or 0x302 for multiple devices */ |
| zpci_remove_reserved_devices(); |
| clp_scan_pci_devices(); |
| break; |
| case 0x0308: /* Standby -> Reserved */ |
| if (!zdev) |
| break; |
| zpci_device_reserved(zdev); |
| break; |
| default: |
| break; |
| } |
| if (existing_zdev) { |
| mutex_unlock(&zdev->state_lock); |
| zpci_zdev_put(zdev); |
| } |
| } |
| |
| void zpci_event_availability(void *data) |
| { |
| if (zpci_is_enabled()) |
| __zpci_event_availability(data); |
| } |