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

Lizhi Hou
2023-09-11T21:31:05Z

On 9/11/23 08:13, Herve Codina wrote:
> Hi Lizhi,
>
> On Tue, 15 Aug 2023 10:19:57 -0700
> Lizhi Hou <lizhi.hou@amd.com> 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
>