linux/drivers/of/platform.c
David Brazdil f396ededbd misc: open-dice: Add driver to expose DICE data to userspace
Open Profile for DICE is an open protocol for measured boot compatible
with the Trusted Computing Group's Device Identifier Composition
Engine (DICE) specification. The generated Compound Device Identifier
(CDI) certificates represent the hardware/software combination measured
by DICE, and can be used for remote attestation and sealing.

Add a driver that exposes reserved memory regions populated by firmware
with DICE CDIs and exposes them to userspace via a character device.

Userspace obtains the memory region's size from read() and calls mmap()
to create a mapping of the memory region in its address space. The
mapping is not allowed to be write+shared, giving userspace a guarantee
that the data were not overwritten by another process.

Userspace can also call write(), which triggers a wipe of the DICE data
by the driver. Because both the kernel and userspace mappings use
write-combine semantics, all clients observe the memory as zeroed after
the syscall has returned.

Cc: Andrew Scull <ascull@google.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: David Brazdil <dbrazdil@google.com>
Link: https://lore.kernel.org/r/20220126231237.529308-3-dbrazdil@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-04 16:45:39 +01:00

741 lines
20 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
* <benh@kernel.crashing.org>
* and Arnd Bergmann, IBM Corp.
* Merged from powerpc/kernel/of_platform.c and
* sparc{,64}/kernel/of_device.c by Stephen Rothwell
*/
#define pr_fmt(fmt) "OF: " fmt
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/amba/bus.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
const struct of_device_id of_default_bus_match_table[] = {
{ .compatible = "simple-bus", },
{ .compatible = "simple-mfd", },
{ .compatible = "isa", },
#ifdef CONFIG_ARM_AMBA
{ .compatible = "arm,amba-bus", },
#endif /* CONFIG_ARM_AMBA */
{} /* Empty terminated list */
};
static const struct of_device_id of_skipped_node_table[] = {
{ .compatible = "operating-points-v2", },
{} /* Empty terminated list */
};
/**
* of_find_device_by_node - Find the platform_device associated with a node
* @np: Pointer to device tree node
*
* Takes a reference to the embedded struct device which needs to be dropped
* after use.
*
* Return: platform_device pointer, or NULL if not found
*/
struct platform_device *of_find_device_by_node(struct device_node *np)
{
struct device *dev;
dev = bus_find_device_by_of_node(&platform_bus_type, np);
return dev ? to_platform_device(dev) : NULL;
}
EXPORT_SYMBOL(of_find_device_by_node);
#ifdef CONFIG_OF_ADDRESS
/*
* The following routines scan a subtree and registers a device for
* each applicable node.
*
* Note: sparc doesn't use these routines because it has a different
* mechanism for creating devices from device tree nodes.
*/
/**
* of_device_make_bus_id - Use the device node data to assign a unique name
* @dev: pointer to device structure that is linked to a device tree node
*
* This routine will first try using the translated bus address to
* derive a unique name. If it cannot, then it will prepend names from
* parent nodes until a unique name can be derived.
*/
static void of_device_make_bus_id(struct device *dev)
{
struct device_node *node = dev->of_node;
const __be32 *reg;
u64 addr;
u32 mask;
/* Construct the name, using parent nodes if necessary to ensure uniqueness */
while (node->parent) {
/*
* If the address can be translated, then that is as much
* uniqueness as we need. Make it the first component and return
*/
reg = of_get_property(node, "reg", NULL);
if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
if (!of_property_read_u32(node, "mask", &mask))
dev_set_name(dev, dev_name(dev) ? "%llx.%x.%pOFn:%s" : "%llx.%x.%pOFn",
addr, ffs(mask) - 1, node, dev_name(dev));
else
dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
addr, node, dev_name(dev));
return;
}
/* format arguments only used if dev_name() resolves to NULL */
dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
kbasename(node->full_name), dev_name(dev));
node = node->parent;
}
}
/**
* of_device_alloc - Allocate and initialize an of_device
* @np: device node to assign to device
* @bus_id: Name to assign to the device. May be null to use default name.
* @parent: Parent device.
*/
struct platform_device *of_device_alloc(struct device_node *np,
const char *bus_id,
struct device *parent)
{
struct platform_device *dev;
int rc, i, num_reg = 0, num_irq;
struct resource *res, temp_res;
dev = platform_device_alloc("", PLATFORM_DEVID_NONE);
if (!dev)
return NULL;
/* count the io and irq resources */
while (of_address_to_resource(np, num_reg, &temp_res) == 0)
num_reg++;
num_irq = of_irq_count(np);
/* Populate the resource table */
if (num_irq || num_reg) {
res = kcalloc(num_irq + num_reg, sizeof(*res), GFP_KERNEL);
if (!res) {
platform_device_put(dev);
return NULL;
}
dev->num_resources = num_reg + num_irq;
dev->resource = res;
for (i = 0; i < num_reg; i++, res++) {
rc = of_address_to_resource(np, i, res);
WARN_ON(rc);
}
if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
pr_debug("not all legacy IRQ resources mapped for %pOFn\n",
np);
}
dev->dev.of_node = of_node_get(np);
dev->dev.fwnode = &np->fwnode;
dev->dev.parent = parent ? : &platform_bus;
if (bus_id)
dev_set_name(&dev->dev, "%s", bus_id);
else
of_device_make_bus_id(&dev->dev);
return dev;
}
EXPORT_SYMBOL(of_device_alloc);
/**
* of_platform_device_create_pdata - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
* @bus_id: name to assign device
* @platform_data: pointer to populate platform_data pointer with
* @parent: Linux device model parent device.
*
* Return: Pointer to created platform device, or NULL if a device was not
* registered. Unavailable devices will not get registered.
*/
static struct platform_device *of_platform_device_create_pdata(
struct device_node *np,
const char *bus_id,
void *platform_data,
struct device *parent)
{
struct platform_device *dev;
if (!of_device_is_available(np) ||
of_node_test_and_set_flag(np, OF_POPULATED))
return NULL;
dev = of_device_alloc(np, bus_id, parent);
if (!dev)
goto err_clear_flag;
dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
if (!dev->dev.dma_mask)
dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
dev->dev.bus = &platform_bus_type;
dev->dev.platform_data = platform_data;
of_msi_configure(&dev->dev, dev->dev.of_node);
if (of_device_add(dev) != 0) {
platform_device_put(dev);
goto err_clear_flag;
}
return dev;
err_clear_flag:
of_node_clear_flag(np, OF_POPULATED);
return NULL;
}
/**
* of_platform_device_create - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
* @bus_id: name to assign device
* @parent: Linux device model parent device.
*
* Return: Pointer to created platform device, or NULL if a device was not
* registered. Unavailable devices will not get registered.
*/
struct platform_device *of_platform_device_create(struct device_node *np,
const char *bus_id,
struct device *parent)
{
return of_platform_device_create_pdata(np, bus_id, NULL, parent);
}
EXPORT_SYMBOL(of_platform_device_create);
#ifdef CONFIG_ARM_AMBA
static struct amba_device *of_amba_device_create(struct device_node *node,
const char *bus_id,
void *platform_data,
struct device *parent)
{
struct amba_device *dev;
const void *prop;
int ret;
pr_debug("Creating amba device %pOF\n", node);
if (!of_device_is_available(node) ||
of_node_test_and_set_flag(node, OF_POPULATED))
return NULL;
dev = amba_device_alloc(NULL, 0, 0);
if (!dev)
goto err_clear_flag;
/* AMBA devices only support a single DMA mask */
dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
/* setup generic device info */
dev->dev.of_node = of_node_get(node);
dev->dev.fwnode = &node->fwnode;
dev->dev.parent = parent ? : &platform_bus;
dev->dev.platform_data = platform_data;
if (bus_id)
dev_set_name(&dev->dev, "%s", bus_id);
else
of_device_make_bus_id(&dev->dev);
/* Allow the HW Peripheral ID to be overridden */
prop = of_get_property(node, "arm,primecell-periphid", NULL);
if (prop)
dev->periphid = of_read_ulong(prop, 1);
ret = of_address_to_resource(node, 0, &dev->res);
if (ret) {
pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
ret, node);
goto err_free;
}
ret = amba_device_add(dev, &iomem_resource);
if (ret) {
pr_err("amba_device_add() failed (%d) for %pOF\n",
ret, node);
goto err_free;
}
return dev;
err_free:
amba_device_put(dev);
err_clear_flag:
of_node_clear_flag(node, OF_POPULATED);
return NULL;
}
#else /* CONFIG_ARM_AMBA */
static struct amba_device *of_amba_device_create(struct device_node *node,
const char *bus_id,
void *platform_data,
struct device *parent)
{
return NULL;
}
#endif /* CONFIG_ARM_AMBA */
/*
* of_dev_lookup() - Given a device node, lookup the preferred Linux name
*/
static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
struct device_node *np)
{
const struct of_dev_auxdata *auxdata;
struct resource res;
int compatible = 0;
if (!lookup)
return NULL;
auxdata = lookup;
for (; auxdata->compatible; auxdata++) {
if (!of_device_is_compatible(np, auxdata->compatible))
continue;
compatible++;
if (!of_address_to_resource(np, 0, &res))
if (res.start != auxdata->phys_addr)
continue;
pr_debug("%pOF: devname=%s\n", np, auxdata->name);
return auxdata;
}
if (!compatible)
return NULL;
/* Try compatible match if no phys_addr and name are specified */
auxdata = lookup;
for (; auxdata->compatible; auxdata++) {
if (!of_device_is_compatible(np, auxdata->compatible))
continue;
if (!auxdata->phys_addr && !auxdata->name) {
pr_debug("%pOF: compatible match\n", np);
return auxdata;
}
}
return NULL;
}
/**
* of_platform_bus_create() - Create a device for a node and its children.
* @bus: device node of the bus to instantiate
* @matches: match table for bus nodes
* @lookup: auxdata table for matching id and platform_data with device nodes
* @parent: parent for new device, or NULL for top level.
* @strict: require compatible property
*
* Creates a platform_device for the provided device_node, and optionally
* recursively create devices for all the child nodes.
*/
static int of_platform_bus_create(struct device_node *bus,
const struct of_device_id *matches,
const struct of_dev_auxdata *lookup,
struct device *parent, bool strict)
{
const struct of_dev_auxdata *auxdata;
struct device_node *child;
struct platform_device *dev;
const char *bus_id = NULL;
void *platform_data = NULL;
int rc = 0;
/* Make sure it has a compatible property */
if (strict && (!of_get_property(bus, "compatible", NULL))) {
pr_debug("%s() - skipping %pOF, no compatible prop\n",
__func__, bus);
return 0;
}
/* Skip nodes for which we don't want to create devices */
if (unlikely(of_match_node(of_skipped_node_table, bus))) {
pr_debug("%s() - skipping %pOF node\n", __func__, bus);
return 0;
}
if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
pr_debug("%s() - skipping %pOF, already populated\n",
__func__, bus);
return 0;
}
auxdata = of_dev_lookup(lookup, bus);
if (auxdata) {
bus_id = auxdata->name;
platform_data = auxdata->platform_data;
}
if (of_device_is_compatible(bus, "arm,primecell")) {
/*
* Don't return an error here to keep compatibility with older
* device tree files.
*/
of_amba_device_create(bus, bus_id, platform_data, parent);
return 0;
}
dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
if (!dev || !of_match_node(matches, bus))
return 0;
for_each_child_of_node(bus, child) {
pr_debug(" create child: %pOF\n", child);
rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
if (rc) {
of_node_put(child);
break;
}
}
of_node_set_flag(bus, OF_POPULATED_BUS);
return rc;
}
/**
* of_platform_bus_probe() - Probe the device-tree for platform buses
* @root: parent of the first level to probe or NULL for the root of the tree
* @matches: match table for bus nodes
* @parent: parent to hook devices from, NULL for toplevel
*
* Note that children of the provided root are not instantiated as devices
* unless the specified root itself matches the bus list and is not NULL.
*/
int of_platform_bus_probe(struct device_node *root,
const struct of_device_id *matches,
struct device *parent)
{
struct device_node *child;
int rc = 0;
root = root ? of_node_get(root) : of_find_node_by_path("/");
if (!root)
return -EINVAL;
pr_debug("%s()\n", __func__);
pr_debug(" starting at: %pOF\n", root);
/* Do a self check of bus type, if there's a match, create children */
if (of_match_node(matches, root)) {
rc = of_platform_bus_create(root, matches, NULL, parent, false);
} else for_each_child_of_node(root, child) {
if (!of_match_node(matches, child))
continue;
rc = of_platform_bus_create(child, matches, NULL, parent, false);
if (rc) {
of_node_put(child);
break;
}
}
of_node_put(root);
return rc;
}
EXPORT_SYMBOL(of_platform_bus_probe);
/**
* of_platform_populate() - Populate platform_devices from device tree data
* @root: parent of the first level to probe or NULL for the root of the tree
* @matches: match table, NULL to use the default
* @lookup: auxdata table for matching id and platform_data with device nodes
* @parent: parent to hook devices from, NULL for toplevel
*
* Similar to of_platform_bus_probe(), this function walks the device tree
* and creates devices from nodes. It differs in that it follows the modern
* convention of requiring all device nodes to have a 'compatible' property,
* and it is suitable for creating devices which are children of the root
* node (of_platform_bus_probe will only create children of the root which
* are selected by the @matches argument).
*
* New board support should be using this function instead of
* of_platform_bus_probe().
*
* Return: 0 on success, < 0 on failure.
*/
int of_platform_populate(struct device_node *root,
const struct of_device_id *matches,
const struct of_dev_auxdata *lookup,
struct device *parent)
{
struct device_node *child;
int rc = 0;
root = root ? of_node_get(root) : of_find_node_by_path("/");
if (!root)
return -EINVAL;
pr_debug("%s()\n", __func__);
pr_debug(" starting at: %pOF\n", root);
device_links_supplier_sync_state_pause();
for_each_child_of_node(root, child) {
rc = of_platform_bus_create(child, matches, lookup, parent, true);
if (rc) {
of_node_put(child);
break;
}
}
device_links_supplier_sync_state_resume();
of_node_set_flag(root, OF_POPULATED_BUS);
of_node_put(root);
return rc;
}
EXPORT_SYMBOL_GPL(of_platform_populate);
int of_platform_default_populate(struct device_node *root,
const struct of_dev_auxdata *lookup,
struct device *parent)
{
return of_platform_populate(root, of_default_bus_match_table, lookup,
parent);
}
EXPORT_SYMBOL_GPL(of_platform_default_populate);
#ifndef CONFIG_PPC
static const struct of_device_id reserved_mem_matches[] = {
{ .compatible = "qcom,rmtfs-mem" },
{ .compatible = "qcom,cmd-db" },
{ .compatible = "qcom,smem" },
{ .compatible = "ramoops" },
{ .compatible = "nvmem-rmem" },
{ .compatible = "google,open-dice" },
{}
};
static int __init of_platform_default_populate_init(void)
{
struct device_node *node;
device_links_supplier_sync_state_pause();
if (!of_have_populated_dt())
return -ENODEV;
/*
* Handle certain compatibles explicitly, since we don't want to create
* platform_devices for every node in /reserved-memory with a
* "compatible",
*/
for_each_matching_node(node, reserved_mem_matches)
of_platform_device_create(node, NULL, NULL);
node = of_find_node_by_path("/firmware");
if (node) {
of_platform_populate(node, NULL, NULL, NULL);
of_node_put(node);
}
node = of_get_compatible_child(of_chosen, "simple-framebuffer");
of_platform_device_create(node, NULL, NULL);
of_node_put(node);
/* Populate everything else. */
of_platform_default_populate(NULL, NULL, NULL);
return 0;
}
arch_initcall_sync(of_platform_default_populate_init);
static int __init of_platform_sync_state_init(void)
{
device_links_supplier_sync_state_resume();
return 0;
}
late_initcall_sync(of_platform_sync_state_init);
#endif
int of_platform_device_destroy(struct device *dev, void *data)
{
/* Do not touch devices not populated from the device tree */
if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
return 0;
/* Recurse for any nodes that were treated as busses */
if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
device_for_each_child(dev, NULL, of_platform_device_destroy);
of_node_clear_flag(dev->of_node, OF_POPULATED);
of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
if (dev->bus == &platform_bus_type)
platform_device_unregister(to_platform_device(dev));
#ifdef CONFIG_ARM_AMBA
else if (dev->bus == &amba_bustype)
amba_device_unregister(to_amba_device(dev));
#endif
return 0;
}
EXPORT_SYMBOL_GPL(of_platform_device_destroy);
/**
* of_platform_depopulate() - Remove devices populated from device tree
* @parent: device which children will be removed
*
* Complementary to of_platform_populate(), this function removes children
* of the given device (and, recurrently, their children) that have been
* created from their respective device tree nodes (and only those,
* leaving others - eg. manually created - unharmed).
*/
void of_platform_depopulate(struct device *parent)
{
if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
device_for_each_child_reverse(parent, NULL, of_platform_device_destroy);
of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
}
}
EXPORT_SYMBOL_GPL(of_platform_depopulate);
static void devm_of_platform_populate_release(struct device *dev, void *res)
{
of_platform_depopulate(*(struct device **)res);
}
/**
* devm_of_platform_populate() - Populate platform_devices from device tree data
* @dev: device that requested to populate from device tree data
*
* Similar to of_platform_populate(), but will automatically call
* of_platform_depopulate() when the device is unbound from the bus.
*
* Return: 0 on success, < 0 on failure.
*/
int devm_of_platform_populate(struct device *dev)
{
struct device **ptr;
int ret;
if (!dev)
return -EINVAL;
ptr = devres_alloc(devm_of_platform_populate_release,
sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return -ENOMEM;
ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
if (ret) {
devres_free(ptr);
} else {
*ptr = dev;
devres_add(dev, ptr);
}
return ret;
}
EXPORT_SYMBOL_GPL(devm_of_platform_populate);
static int devm_of_platform_match(struct device *dev, void *res, void *data)
{
struct device **ptr = res;
if (!ptr) {
WARN_ON(!ptr);
return 0;
}
return *ptr == data;
}
/**
* devm_of_platform_depopulate() - Remove devices populated from device tree
* @dev: device that requested to depopulate from device tree data
*
* Complementary to devm_of_platform_populate(), this function removes children
* of the given device (and, recurrently, their children) that have been
* created from their respective device tree nodes (and only those,
* leaving others - eg. manually created - unharmed).
*/
void devm_of_platform_depopulate(struct device *dev)
{
int ret;
ret = devres_release(dev, devm_of_platform_populate_release,
devm_of_platform_match, dev);
WARN_ON(ret);
}
EXPORT_SYMBOL_GPL(devm_of_platform_depopulate);
#ifdef CONFIG_OF_DYNAMIC
static int of_platform_notify(struct notifier_block *nb,
unsigned long action, void *arg)
{
struct of_reconfig_data *rd = arg;
struct platform_device *pdev_parent, *pdev;
bool children_left;
switch (of_reconfig_get_state_change(action, rd)) {
case OF_RECONFIG_CHANGE_ADD:
/* verify that the parent is a bus */
if (!of_node_check_flag(rd->dn->parent, OF_POPULATED_BUS))
return NOTIFY_OK; /* not for us */
/* already populated? (driver using of_populate manually) */
if (of_node_check_flag(rd->dn, OF_POPULATED))
return NOTIFY_OK;
/* pdev_parent may be NULL when no bus platform device */
pdev_parent = of_find_device_by_node(rd->dn->parent);
pdev = of_platform_device_create(rd->dn, NULL,
pdev_parent ? &pdev_parent->dev : NULL);
platform_device_put(pdev_parent);
if (pdev == NULL) {
pr_err("%s: failed to create for '%pOF'\n",
__func__, rd->dn);
/* of_platform_device_create tosses the error code */
return notifier_from_errno(-EINVAL);
}
break;
case OF_RECONFIG_CHANGE_REMOVE:
/* already depopulated? */
if (!of_node_check_flag(rd->dn, OF_POPULATED))
return NOTIFY_OK;
/* find our device by node */
pdev = of_find_device_by_node(rd->dn);
if (pdev == NULL)
return NOTIFY_OK; /* no? not meant for us */
/* unregister takes one ref away */
of_platform_device_destroy(&pdev->dev, &children_left);
/* and put the reference of the find */
platform_device_put(pdev);
break;
}
return NOTIFY_OK;
}
static struct notifier_block platform_of_notifier = {
.notifier_call = of_platform_notify,
};
void of_platform_register_reconfig_notifier(void)
{
WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
}
#endif /* CONFIG_OF_DYNAMIC */
#endif /* CONFIG_OF_ADDRESS */