Re: [PATCH V4: 2/3] pci: Provide aer support when the error source id is bad

Zhang, Yanmin
2009-06-15T01:35:29Z

On Fri, 2009-06-12 at 21:51 +0000, Andrew Patterson wrote:
> On Fri, 2009-06-12 at 11:08 +0800, Zhang, Yanmin wrote:
> > ﻿﻿﻿When the bus id part of error source id is equal to 0 or nosourceid=1,
> > kernel probes the AER status registers of all devices under the root port
> > to find the initial error reporter.
Thanks Andrew for your kind comments.

> >
> > ﻿﻿﻿Signed-off-by: ﻿Zhang Yanmin <yanmin.zhang@linux.intel.com>
> >
> > ---
> >
> > --- linux-2.6_next_pciwalk/drivers/pci/pcie/aer/aerdrv_core.c 2009-06-12 05:31:53.000000000 +0800
> > +++ linux-2.6_next_aernoid/drivers/pci/pcie/aer/aerdrv_core.c 2009-06-12 05:39:24.000000000 +0800
> > @@ -26,7 +26,9 @@
> > #include "aerdrv.h"
> >
> > static int forceload;
> > +static int nosourceid;
> > module_param(forceload, bool, 0);
> > +module_param(nosourceid, bool, 0);
> >
> > int pci_enable_pcie_error_reporting(struct pci_dev *dev)
> > {
> > @@ -143,34 +145,82 @@ static void set_downstream_devices_error
> > pci_walk_bus(dev->subordinate, set_device_error_reporting, &enable);
> > }
> >
> > -static int find_device_iter(struct device *device, void *data)
> > +static int compare_device_id(struct pci_dev *dev, struct aer_err_info *e_info)
> > {
> > - struct pci_dev *dev;
> > - u16 id = *(unsigned long *)data;
> > - u8 secondary, subordinate, d_bus = id >> 8;
> > -
> > - if (device->bus == &pci_bus_type) {
> > - dev = to_pci_dev(device);
> > - if (id == ((dev->bus->number << 8) | dev->devfn)) {
> > - /*
> > - * Device ID match
> > - */
> > - *(unsigned long*)data = (unsigned long)device;
> > - return 1;
> > - }
> > -
> > + if (e_info->id == ((dev->bus->number << 8) | dev->devfn)) {
> > /*
> > - * If device is P2P, check if it is an upstream?
> > + * Device ID match
> > */
> > - if (dev->hdr_type & PCI_HEADER_TYPE_BRIDGE) {
> > - pci_read_config_byte(dev, PCI_SECONDARY_BUS,
> > - &secondary);
> > - pci_read_config_byte(dev, PCI_SUBORDINATE_BUS,
> > - &subordinate);
> > - if (d_bus >= secondary && d_bus <= subordinate) {
> > - *(unsigned long*)data = (unsigned long)device;
> > - return 1;
> > - }
> > + e_info->dev = dev;
> > + return 1;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +#define PCI_BUS(x) (((x) >> 8) & 0xff)
> > +
> > +static int find_device_iter(struct pci_dev *dev, void *data)
> > +{
> > + int pos;
> > + u32 status;
> > + u32 mask;
> > + u16 reg16;
> > + struct aer_err_info *e_info = (struct aer_err_info *)data;
> > +
> > + /*
> > + * When bus id is equal to 0, it might be a bad id
> > + * reported by root port.
> > + */
> > + if (!nosourceid && (PCI_BUS(e_info->id) != 0))
> > + return compare_device_id(dev, e_info);
> > +
> > + /*
> > + * Next is to check when bus id is equal to 0 or
> > + * nosourceid==y. Some ports might lose the bus
> > + * id of error source id. We check AER status
> > + * registers to find the initial reporter.
> > + */
> > + if (atomic_read(&dev->enable_cnt) == 0)
> > + return 0;
> > + pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
> > + if (!pos)
> > + return 0;
> > + /* Check if AER is enabled */
> > + pci_read_config_word(dev, pos+PCI_EXP_DEVCTL, &reg16);
> > + if (!(reg16 & (
> > + PCI_EXP_DEVCTL_CERE |
> > + PCI_EXP_DEVCTL_NFERE |
> > + PCI_EXP_DEVCTL_FERE |
> > + PCI_EXP_DEVCTL_URRE)))
> > + return 0;
> > + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
> > + if (!pos)
> > + return 0;
> > +
> > + status = 0;
> > + mask = 0;
> > + if (e_info->severity == AER_CORRECTABLE) {
> > + pci_read_config_dword(dev,
> > + pos + PCI_ERR_COR_STATUS,
> > + &status);
> > + pci_read_config_dword(dev,
> > + pos + PCI_ERR_COR_MASK,
> > + &mask);
> > + if (status & ERR_CORRECTABLE_ERROR_MASK & ~mask) {
> > + e_info->dev = dev;
> > + return 1;
> > + }
> > + } else {
> > + pci_read_config_dword(dev,
> > + pos + PCI_ERR_UNCOR_STATUS,
> > + &status);
> > + pci_read_config_dword(dev,
> > + pos + PCI_ERR_UNCOR_MASK,
> > + &mask);
> > + if (status & ERR_UNCORRECTABLE_ERROR_MASK & ~mask) {
> > + e_info->dev = dev;
> > + return 1;
> > }
> > }
> >
> > @@ -180,33 +230,23 @@ static int find_device_iter(struct devic
> > /**
> > * find_source_device - search through device hierarchy for source device
> > * @parent: pointer to Root Port pci_dev data structure
> > - * @id: device ID of agent who sends an error message to this Root Port
> > + * @err_info: including detailed error information such like id
> > *
> > * Invoked when error is detected at the Root Port.
> > */
> > -static struct device* find_source_device(struct pci_dev *parent, u16 id)
> > +static void find_source_device(struct pci_dev *parent,
> > + struct aer_err_info *e_info)
> > {
> > struct pci_dev *dev = parent;
> > - struct device *device;
> > - unsigned long device_addr;
> > - int status;
> > + int result;
> >
> > /* Is Root Port an agent that sends error message? */
> > - if (id == ((dev->bus->number << 8) | dev->devfn))
> > - return &dev->dev;
> > -
> > - do {
> > - device_addr = id;
> > - if ((status = device_for_each_child(&dev->dev,
> > - &device_addr, find_device_iter))) {
> > - device = (struct device*)device_addr;
> > - dev = to_pci_dev(device);
> > - if (id == ((dev->bus->number << 8) | dev->devfn))
> > - return device;
> > - }
> > - }while (status);
> > + result = find_device_iter(dev, e_info);
> > + if (result)
> > + return;
> >
> > - return NULL;
> > + pci_walk_bus(parent->subordinate, find_device_iter, e_info);
>
> Minor nit. This return is
Yes. I will delete it. Sometimes it can be clearer.

>
> > + return;
> > }
> >
>
> Minor. The e_info goes to pointer changes probably belong in a separate
> patch.
Yes. I will double-check it. I really got a headache to create a series of
small patches. :)

>
> > static int report_error_detected(struct pci_dev *dev, void *data)
> > @@ -501,12 +541,12 @@ static pci_ers_result_t do_recovery(stru
> > */
> > static void handle_error_source(struct pcie_device * aerdev,
> > struct pci_dev *dev,
> > - struct aer_err_info info)
> > + struct aer_err_info *info)
> > {
> > pci_ers_result_t status = 0;
> > int pos;
> >
> > - if (info.severity == AER_CORRECTABLE) {
> > + if (info->severity == AER_CORRECTABLE) {
> > /*
> > * Correctable error does not need software intevention.
> > * No need to go through error recovery process.
> > @@ -514,9 +554,9 @@ static void handle_error_source(struct p
> > pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
> > if (pos)
> > pci_write_config_dword(dev, pos + PCI_ERR_COR_STATUS,
> > - info.status);
> > + info->status);
> > } else {
> > - status = do_recovery(aerdev, dev, info.severity);
> > + status = do_recovery(aerdev, dev, info->severity);
> > if (status == PCI_ERS_RESULT_RECOVERED) {
> > dev_printk(KERN_DEBUG, &dev->dev, "AER driver "
> > "successfully recovered\n");
> > @@ -673,10 +713,13 @@ static int get_device_error_info(struct
> > static void aer_isr_one_error(struct pcie_device *p_device,
> > struct aer_err_source *e_src)
> > {
> > - struct device *s_device;
> > - struct aer_err_info e_info = {0, 0, 0,};
> > + struct aer_err_info *e_info;
> > int i;
> > - u16 id;
> > +
> > + /* struct aer_err_info might be big, so we allocate it with slab */
> > + e_info = kmalloc(sizeof(struct aer_err_info), GFP_KERNEL);
> > + if (e_info == NULL)
> > + return;
> >
> Should we get some sort of warning here? We might be concealing PCIe
> errors when out of memory.
I will add a warning.

>
> > /*
> > * There is a possibility that both correctable error and
> > @@ -688,31 +731,37 @@ static void aer_isr_one_error(struct pci
> > if (!(e_src->status & i))
> > continue;
> >
> > + memset(e_info, 0, sizeof(struct aer_err_info));
> > +
> > /* Init comprehensive error information */
> > if (i & PCI_ERR_ROOT_COR_RCV) {
> > - id = ERR_COR_ID(e_src->id);
> > - e_info.severity = AER_CORRECTABLE;
> > + e_info->id = ERR_COR_ID(e_src->id);
> > + e_info->severity = AER_CORRECTABLE;
> > } else {
> > - id = ERR_UNCOR_ID(e_src->id);
> > - e_info.severity = ((e_src->status >> 6) & 1);
> > + e_info->id = ERR_UNCOR_ID(e_src->id);
> > + e_info->severity = ((e_src->status >> 6) & 1);
> > }
> > if (e_src->status &
> > (PCI_ERR_ROOT_MULTI_COR_RCV |
> > PCI_ERR_ROOT_MULTI_UNCOR_RCV))
> > - e_info.flags |= AER_MULTI_ERROR_VALID_FLAG;
> > - if (!(s_device = find_source_device(p_device->port, id))) {
> > + e_info->flags |= AER_MULTI_ERROR_VALID_FLAG;
> > +
> > + find_source_device(p_device->port, e_info);
> > + if (e_info->dev == NULL) {
> > printk(KERN_DEBUG "%s->can't find device of ID%04x\n",
> > - __func__, id);
> > + __func__, e_info->id);
> > continue;
> > }
> > - if (get_device_error_info(to_pci_dev(s_device), &e_info) ==
> > + if (get_device_error_info(e_info->dev, e_info) ==
> > AER_SUCCESS) {
> > - aer_print_error(to_pci_dev(s_device), &e_info);
> > + aer_print_error(e_info->dev, e_info);
> > handle_error_source(p_device,
> > - to_pci_dev(s_device),
> > + e_info->dev,
> > e_info);
> > }
> > }
> > +
> > + kfree(e_info);
> > }
> >
> > /**
> > --- linux-2.6_next_pciwalk/drivers/pci/pcie/aer/aerdrv.h 2009-06-12 05:27:46.000000000 +0800
> > +++ linux-2.6_next_aernoid/drivers/pci/pcie/aer/aerdrv.h 2009-06-12 05:39:24.000000000 +0800
> > @@ -58,6 +58,8 @@ struct header_log_regs {
> > };
> >
> > struct aer_err_info {
> > + struct pci_dev *dev;
> > + u16 id;
> > int severity; /* 0:NONFATAL | 1:FATAL | 2:COR */
> > int flags;
> > unsigned int status; /* COR/UNCOR Error Status */
> > --- linux-2.6_next_pciwalk/Documentation/PCI/pcieaer-howto.txt 2009-06-12 05:27:40.000000000 +0800
> > +++ linux-2.6_next_aernoid/Documentation/PCI/pcieaer-howto.txt 2009-06-12 05:39:24.000000000 +0800
> > @@ -60,6 +60,8 @@ forceload, a parameter of type bool, cou
> > be initiated although firmwares have no _OSC support. To enable the
> > walkaround, pls. add aerdriver.forceload=y to kernel boot parameter line
> > when booting kernel. Note that forceload=n by default.
>
>
> We need a new paragraph here.
Yes. I will change it.

> > +nosourceid, another parameter of type bool, is used when hardware (mostly
> > +chipset) has errata that root ports couldn't get error reporting source id.
> >
>
> Perhaps ".. can be used when broken hardware (mostly chipsets) has root
> ports that cannot obtain the reporting source ID."
Good. I will do.

>
> > 2.3 AER error output
> > When a PCI-E AER error is captured, an error message will be outputed to