diff options
| -rw-r--r-- | arch/powerpc/kernel/eeh.c | 139 |
1 files changed, 138 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c index 2b3c03215a95..0a91dee51245 100644 --- a/arch/powerpc/kernel/eeh.c +++ b/arch/powerpc/kernel/eeh.c @@ -1892,7 +1892,8 @@ static ssize_t eeh_dev_check_write(struct file *filp, char buf[20]; int ret; - ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count); + memset(buf, 0, sizeof(buf)); + ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count); if (!ret) return -EFAULT; @@ -1929,6 +1930,139 @@ static const struct file_operations eeh_dev_check_fops = { .read = eeh_debugfs_dev_usage, }; +static int eeh_debugfs_break_device(struct pci_dev *pdev) +{ + struct resource *bar = NULL; + void __iomem *mapped; + u16 old, bit; + int i, pos; + + /* Do we have an MMIO BAR to disable? */ + for (i = 0; i <= PCI_STD_RESOURCE_END; i++) { + struct resource *r = &pdev->resource[i]; + + if (!r->flags || !r->start) + continue; + if (r->flags & IORESOURCE_IO) + continue; + if (r->flags & IORESOURCE_UNSET) + continue; + + bar = r; + break; + } + + if (!bar) { + pci_err(pdev, "Unable to find Memory BAR to cause EEH with\n"); + return -ENXIO; + } + + pci_err(pdev, "Going to break: %pR\n", bar); + + if (pdev->is_virtfn) { +#ifndef CONFIG_IOV + return -ENXIO; +#else + /* + * VFs don't have a per-function COMMAND register, so the best + * we can do is clear the Memory Space Enable bit in the PF's + * SRIOV control reg. + * + * Unfortunately, this requires that we have a PF (i.e doesn't + * work for a passed-through VF) and it has the potential side + * effect of also causing an EEH on every other VF under the + * PF. Oh well. + */ + pdev = pdev->physfn; + if (!pdev) + return -ENXIO; /* passed through VFs have no PF */ + + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_SRIOV); + pos += PCI_SRIOV_CTRL; + bit = PCI_SRIOV_CTRL_MSE; +#endif /* !CONFIG_IOV */ + } else { + bit = PCI_COMMAND_MEMORY; + pos = PCI_COMMAND; + } + + /* + * Process here is: + * + * 1. Disable Memory space. + * + * 2. Perform an MMIO to the device. This should result in an error + * (CA / UR) being raised by the device which results in an EEH + * PE freeze. Using the in_8() accessor skips the eeh detection hook + * so the freeze hook so the EEH Detection machinery won't be + * triggered here. This is to match the usual behaviour of EEH + * where the HW will asyncronously freeze a PE and it's up to + * the kernel to notice and deal with it. + * + * 3. Turn Memory space back on. This is more important for VFs + * since recovery will probably fail if we don't. For normal + * the COMMAND register is reset as a part of re-initialising + * the device. + * + * Breaking stuff is the point so who cares if it's racy ;) + */ + pci_read_config_word(pdev, pos, &old); + + mapped = ioremap(bar->start, PAGE_SIZE); + if (!mapped) { + pci_err(pdev, "Unable to map MMIO BAR %pR\n", bar); + return -ENXIO; + } + + pci_write_config_word(pdev, pos, old & ~bit); + in_8(mapped); + pci_write_config_word(pdev, pos, old); + + iounmap(mapped); + + return 0; +} + +static ssize_t eeh_dev_break_write(struct file *filp, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + uint32_t domain, bus, dev, fn; + struct pci_dev *pdev; + char buf[20]; + int ret; + + memset(buf, 0, sizeof(buf)); + ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count); + if (!ret) + return -EFAULT; + + ret = sscanf(buf, "%x:%x:%x.%x", &domain, &bus, &dev, &fn); + if (ret != 4) { + pr_err("%s: expected 4 args, got %d\n", __func__, ret); + return -EINVAL; + } + + pdev = pci_get_domain_bus_and_slot(domain, bus, (dev << 3) | fn); + if (!pdev) + return -ENODEV; + + ret = eeh_debugfs_break_device(pdev); + pci_dev_put(pdev); + + if (ret < 0) + return ret; + + return count; +} + +static const struct file_operations eeh_dev_break_fops = { + .open = simple_open, + .llseek = no_llseek, + .write = eeh_dev_break_write, + .read = eeh_debugfs_dev_usage, +}; + #endif static int __init eeh_init_proc(void) @@ -1947,6 +2081,9 @@ static int __init eeh_init_proc(void) debugfs_create_file_unsafe("eeh_dev_check", 0600, powerpc_debugfs_root, NULL, &eeh_dev_check_fops); + debugfs_create_file_unsafe("eeh_dev_break", 0600, + powerpc_debugfs_root, NULL, + &eeh_dev_break_fops); debugfs_create_file_unsafe("eeh_force_recover", 0600, powerpc_debugfs_root, NULL, &eeh_force_recover_fops); |