Re: [PATCH V13 2/5] PCI: Create device tree node for bridge

[Lizhi Hou]

On 9/11/23 08:13, Herve Codina wrote:
> Hi Lizhi,
>
> On Tue, 15 Aug 2023 10:19:57 -0700
> Lizhi Hou <lizhi.hou@xxxxxxx> wrote:
> ...
> > +void of_pci_make_dev_node(struct pci_dev *pdev)
> > +{
> > +	struct device_node *ppnode, *np = NULL;
> > +	const char *pci_type;
> > +	struct of_changeset *cset;
> > +	const char *name;
> > +	int ret;
> > +
> > +	/*
> > +	 * If there is already a device tree node linked to this device,
> > +	 * return immediately.
> > +	 */
> > +	if (pci_device_to_OF_node(pdev))
> > +		return;
> > +
> > +	/* Check if there is device tree node for parent device */
> > +	if (!pdev->bus->self)
> > +		ppnode = pdev->bus->dev.of_node;
> > +	else
> > +		ppnode = pdev->bus->self->dev.of_node;
> > +	if (!ppnode)
> > +		return;
> > +
> > +	if (pci_is_bridge(pdev))
> > +		pci_type = "pci";
> > +	else
> > +		pci_type = "dev";
> > +
> > +	name = kasprintf(GFP_KERNEL, "%s@%x,%x", pci_type,
> > +			 PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
> > +	if (!name)
> > +		return;
> > +
> > +	cset = kmalloc(sizeof(*cset), GFP_KERNEL);
> > +	if (!cset)
> > +		goto failed;
> > +	of_changeset_init(cset);
> > +
> > +	np = of_changeset_create_node(ppnode, name, cset);
> > +	if (!np)
> > +		goto failed;
> The "goto failed" will leak the cset previously allocated.
>
> np->data = cset; (next line) allows to free the cset when the node is destroyed
> (of_node_put() calls). When the node cannot be created, the allocated cset should
> be freed.
Thanks for pointing this out.
> > +	np->data = cset;
> > +
> > +	ret = of_pci_add_properties(pdev, cset, np);
> > +	if (ret)
> > +		goto failed;
> > +
> > +	ret = of_changeset_apply(cset);
> > +	if (ret)
> > +		goto failed;
> > +
> > +	pdev->dev.of_node = np;
> > +	kfree(name);
> > +
> > +	return;
> > +
> > +failed:
> > +	if (np)
> > +		of_node_put(np);
> > +	kfree(name);
> > +}
> > +#endif
> > +
> >   #endif /* CONFIG_PCI */
> >   
> ...
> > +static int of_pci_prop_intr_map(struct pci_dev *pdev, struct of_changeset *ocs,
> > +				struct device_node *np)
> > +{
> > +	struct of_phandle_args out_irq[OF_PCI_MAX_INT_PIN];
> > +	u32 i, addr_sz[OF_PCI_MAX_INT_PIN], map_sz = 0;
> > +	__be32 laddr[OF_PCI_ADDRESS_CELLS] = { 0 };
> > +	u32 int_map_mask[] = { 0xffff00, 0, 0, 7 };
> > +	struct device_node *pnode;
> > +	struct pci_dev *child;
> > +	u32 *int_map, *mapp;
> > +	int ret;
> > +	u8 pin;
> > +
> > +	pnode = pci_device_to_OF_node(pdev->bus->self);
> > +	if (!pnode)
> > +		pnode = pci_bus_to_OF_node(pdev->bus);
> > +
> > +	if (!pnode) {
> > +		pci_err(pdev, "failed to get parent device node");
> > +		return -EINVAL;
> > +	}
> > +
> > +	laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
> > +	for (pin = 1; pin <= OF_PCI_MAX_INT_PIN;  pin++) {
> > +		i = pin - 1;
> > +		out_irq[i].np = pnode;
> > +		out_irq[i].args_count = 1;
> > +		out_irq[i].args[0] = pin;
> > +		ret = of_irq_parse_raw(laddr, &out_irq[i]);
> > +		if (ret) {
> > +			pci_err(pdev, "parse irq %d failed, ret %d", pin, ret);
> > +			continue;
> > +		}
> > +		ret = of_property_read_u32(out_irq[i].np, "#address-cells",
> > +					   &addr_sz[i]);
> > +		if (ret)
> > +			addr_sz[i] = 0;
> > +	}
> if of_irq_parse_raw() fails, addr_sz[i] is not initialized and map_sz bellow is
> computed with uninitialized values.
> On the test I did, this lead to a kernel crash due to the following kcalloc()
> called with incorrect values.
>
> Are interrupt-map and interrupt-map-mask properties needed in all cases ?
> I mean are they mandatory for the host pci bridge ?
interrupt-map is required for bridges when a legacy interrupt device is 
underneath. Otherwise, of_irq_parse_pci() needs to be changed for legacy 
interrupt device. Please see my previous patch and comments.
> > +
> > +	list_for_each_entry(child, &pdev->subordinate->devices, bus_list) {
> > +		for (pin = 1; pin <= OF_PCI_MAX_INT_PIN; pin++) {
> > +			i = pci_swizzle_interrupt_pin(child, pin) - 1;
> > +			map_sz += 5 + addr_sz[i] + out_irq[i].args_count;
> of_irq_parse_raw() can fail on some pins.
> Is it correct to set map_sz based on information related to all pins even if
> of_irq_parse_raw() previously failed on some pins ?

I think the interrupt-map pair should be skipped if of_irq_parse_raw() 
is failed. Thanks.


Lizhi

> > +		}
> > +	}
> > +
> > +	int_map = kcalloc(map_sz, sizeof(u32), GFP_KERNEL);
> > +	mapp = int_map;
> > +
> > +	list_for_each_entry(child, &pdev->subordinate->devices, bus_list) {
> > +		for (pin = 1; pin <= OF_PCI_MAX_INT_PIN; pin++) {
> > +			*mapp = (child->bus->number << 16) |
> > +				(child->devfn << 8);
> > +			mapp += OF_PCI_ADDRESS_CELLS;
> > +			*mapp = pin;
> > +			mapp++;
> > +			i = pci_swizzle_interrupt_pin(child, pin) - 1;
> > +			*mapp = out_irq[i].np->phandle;
> > +			mapp++;
> > +			if (addr_sz[i]) {
> > +				ret = of_property_read_u32_array(out_irq[i].np,
> > +								 "reg", mapp,
> > +								 addr_sz[i]);
> > +				if (ret)
> > +					goto failed;
> > +			}
> > +			mapp += addr_sz[i];
> > +			memcpy(mapp, out_irq[i].args,
> > +			       out_irq[i].args_count * sizeof(u32));
> > +			mapp += out_irq[i].args_count;
> > +		}
> > +	}
> > +
> > +	ret = of_changeset_add_prop_u32_array(ocs, np, "interrupt-map", int_map,
> > +					      map_sz);
> > +	if (ret)
> > +		goto failed;
> > +
> > +	ret = of_changeset_add_prop_u32(ocs, np, "#interrupt-cells", 1);
> > +	if (ret)
> > +		goto failed;
> > +
> > +	ret = of_changeset_add_prop_u32_array(ocs, np, "interrupt-map-mask",
> > +					      int_map_mask,
> > +					      ARRAY_SIZE(int_map_mask));
> > +	if (ret)
> > +		goto failed;
> > +
> > +	kfree(int_map);
> > +	return 0;
> > +
> > +failed:
> > +	kfree(int_map);
> > +	return ret;
> > +}
> > +
> ...
>
> Regards,
> Hervé