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

[Zhang, Yanmin]

On Fri, 2009-06-12 at 21:51 +0000, Andrew Patterson wrote:
> On Fri, 2009-06-12 at 11:08 +0800, Zhang, Yanmin wrote:
> > ïïïWhen 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.

> > 
> > ïïïSigned-off-by: ïZhang Yanmin <yanmin.zhang@xxxxxxxxxxxxxxx>
> > 
> > ---
> > 
> > --- 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


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