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![Andy Shevchenko](/assets/img/avatar_default.png)
Currently it's possible to iterate over the dangling pointer in case the device suddenly disappears. This may happen becase callers put it at the end of a loop. Instead, let's move that call inside acpi_dev_get_next_match_dev(). Fixes:803abec64e
("media: ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver") Fixes:bf263f64e8
("media: ACPI / bus: Add acpi_dev_get_next_match_dev() and helper macro") Fixes:edbd1bc495
("efi/dev-path-parser: Switch to use for_each_acpi_dev_match()") Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Daniel Scally <djrscally@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
182 lines
5.3 KiB
C
182 lines
5.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* dev-path-parser.c - EFI Device Path parser
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* Copyright (C) 2016 Lukas Wunner <lukas@wunner.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License (version 2) as
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* published by the Free Software Foundation.
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*/
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#include <linux/acpi.h>
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#include <linux/efi.h>
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#include <linux/pci.h>
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static long __init parse_acpi_path(const struct efi_dev_path *node,
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struct device *parent, struct device **child)
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{
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char hid[ACPI_ID_LEN], uid[11]; /* UINT_MAX + null byte */
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struct acpi_device *adev;
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struct device *phys_dev;
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if (node->header.length != 12)
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return -EINVAL;
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sprintf(hid, "%c%c%c%04X",
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'A' + ((node->acpi.hid >> 10) & 0x1f) - 1,
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'A' + ((node->acpi.hid >> 5) & 0x1f) - 1,
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'A' + ((node->acpi.hid >> 0) & 0x1f) - 1,
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node->acpi.hid >> 16);
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sprintf(uid, "%u", node->acpi.uid);
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for_each_acpi_dev_match(adev, hid, NULL, -1) {
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if (adev->pnp.unique_id && !strcmp(adev->pnp.unique_id, uid))
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break;
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if (!adev->pnp.unique_id && node->acpi.uid == 0)
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break;
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}
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if (!adev)
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return -ENODEV;
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phys_dev = acpi_get_first_physical_node(adev);
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if (phys_dev) {
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*child = get_device(phys_dev);
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acpi_dev_put(adev);
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} else
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*child = &adev->dev;
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return 0;
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}
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static int __init match_pci_dev(struct device *dev, void *data)
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{
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unsigned int devfn = *(unsigned int *)data;
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return dev_is_pci(dev) && to_pci_dev(dev)->devfn == devfn;
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}
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static long __init parse_pci_path(const struct efi_dev_path *node,
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struct device *parent, struct device **child)
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{
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unsigned int devfn;
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if (node->header.length != 6)
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return -EINVAL;
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if (!parent)
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return -EINVAL;
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devfn = PCI_DEVFN(node->pci.dev, node->pci.fn);
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*child = device_find_child(parent, &devfn, match_pci_dev);
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if (!*child)
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return -ENODEV;
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return 0;
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}
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/*
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* Insert parsers for further node types here.
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*
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* Each parser takes a pointer to the @node and to the @parent (will be NULL
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* for the first device path node). If a device corresponding to @node was
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* found below @parent, its reference count should be incremented and the
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* device returned in @child.
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*
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* The return value should be 0 on success or a negative int on failure.
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* The special return values 0x01 (EFI_DEV_END_INSTANCE) and 0xFF
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* (EFI_DEV_END_ENTIRE) signal the end of the device path, only
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* parse_end_path() is supposed to return this.
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*
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* Be sure to validate the node length and contents before commencing the
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* search for a device.
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*/
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static long __init parse_end_path(const struct efi_dev_path *node,
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struct device *parent, struct device **child)
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{
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if (node->header.length != 4)
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return -EINVAL;
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if (node->header.sub_type != EFI_DEV_END_INSTANCE &&
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node->header.sub_type != EFI_DEV_END_ENTIRE)
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return -EINVAL;
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if (!parent)
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return -ENODEV;
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*child = get_device(parent);
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return node->header.sub_type;
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}
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/**
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* efi_get_device_by_path - find device by EFI Device Path
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* @node: EFI Device Path
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* @len: maximum length of EFI Device Path in bytes
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*
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* Parse a series of EFI Device Path nodes at @node and find the corresponding
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* device. If the device was found, its reference count is incremented and a
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* pointer to it is returned. The caller needs to drop the reference with
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* put_device() after use. The @node pointer is updated to point to the
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* location immediately after the "End of Hardware Device Path" node.
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*
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* If another Device Path instance follows, @len is decremented by the number
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* of bytes consumed. Otherwise @len is set to %0.
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*
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* If a Device Path node is malformed or its corresponding device is not found,
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* @node is updated to point to this offending node and an ERR_PTR is returned.
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*
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* If @len is initially %0, the function returns %NULL. Thus, to iterate over
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* all instances in a path, the following idiom may be used:
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*
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* while (!IS_ERR_OR_NULL(dev = efi_get_device_by_path(&node, &len))) {
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* // do something with dev
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* put_device(dev);
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* }
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* if (IS_ERR(dev))
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* // report error
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*
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* Devices can only be found if they're already instantiated. Most buses
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* instantiate devices in the "subsys" initcall level, hence the earliest
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* initcall level in which this function should be called is "fs".
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*
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* Returns the device on success or
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* %ERR_PTR(-ENODEV) if no device was found,
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* %ERR_PTR(-EINVAL) if a node is malformed or exceeds @len,
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* %ERR_PTR(-ENOTSUPP) if support for a node type is not yet implemented.
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*/
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struct device * __init efi_get_device_by_path(const struct efi_dev_path **node,
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size_t *len)
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{
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struct device *parent = NULL, *child;
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long ret = 0;
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if (!*len)
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return NULL;
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while (!ret) {
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if (*len < 4 || *len < (*node)->header.length)
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ret = -EINVAL;
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else if ((*node)->header.type == EFI_DEV_ACPI &&
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(*node)->header.sub_type == EFI_DEV_BASIC_ACPI)
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ret = parse_acpi_path(*node, parent, &child);
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else if ((*node)->header.type == EFI_DEV_HW &&
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(*node)->header.sub_type == EFI_DEV_PCI)
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ret = parse_pci_path(*node, parent, &child);
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else if (((*node)->header.type == EFI_DEV_END_PATH ||
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(*node)->header.type == EFI_DEV_END_PATH2))
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ret = parse_end_path(*node, parent, &child);
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else
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ret = -ENOTSUPP;
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put_device(parent);
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if (ret < 0)
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return ERR_PTR(ret);
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parent = child;
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*node = (void *)*node + (*node)->header.length;
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*len -= (*node)->header.length;
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}
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if (ret == EFI_DEV_END_ENTIRE)
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*len = 0;
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return child;
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}
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