cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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of_iommu.c (4285B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * OF helpers for IOMMU
      4 *
      5 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
      6 */
      7
      8#include <linux/export.h>
      9#include <linux/iommu.h>
     10#include <linux/limits.h>
     11#include <linux/module.h>
     12#include <linux/msi.h>
     13#include <linux/of.h>
     14#include <linux/of_iommu.h>
     15#include <linux/of_pci.h>
     16#include <linux/pci.h>
     17#include <linux/slab.h>
     18#include <linux/fsl/mc.h>
     19
     20#define NO_IOMMU	1
     21
     22static int of_iommu_xlate(struct device *dev,
     23			  struct of_phandle_args *iommu_spec)
     24{
     25	const struct iommu_ops *ops;
     26	struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
     27	int ret;
     28
     29	ops = iommu_ops_from_fwnode(fwnode);
     30	if ((ops && !ops->of_xlate) ||
     31	    !of_device_is_available(iommu_spec->np))
     32		return NO_IOMMU;
     33
     34	ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
     35	if (ret)
     36		return ret;
     37	/*
     38	 * The otherwise-empty fwspec handily serves to indicate the specific
     39	 * IOMMU device we're waiting for, which will be useful if we ever get
     40	 * a proper probe-ordering dependency mechanism in future.
     41	 */
     42	if (!ops)
     43		return driver_deferred_probe_check_state(dev);
     44
     45	if (!try_module_get(ops->owner))
     46		return -ENODEV;
     47
     48	ret = ops->of_xlate(dev, iommu_spec);
     49	module_put(ops->owner);
     50	return ret;
     51}
     52
     53static int of_iommu_configure_dev_id(struct device_node *master_np,
     54				     struct device *dev,
     55				     const u32 *id)
     56{
     57	struct of_phandle_args iommu_spec = { .args_count = 1 };
     58	int err;
     59
     60	err = of_map_id(master_np, *id, "iommu-map",
     61			 "iommu-map-mask", &iommu_spec.np,
     62			 iommu_spec.args);
     63	if (err)
     64		return err == -ENODEV ? NO_IOMMU : err;
     65
     66	err = of_iommu_xlate(dev, &iommu_spec);
     67	of_node_put(iommu_spec.np);
     68	return err;
     69}
     70
     71static int of_iommu_configure_dev(struct device_node *master_np,
     72				  struct device *dev)
     73{
     74	struct of_phandle_args iommu_spec;
     75	int err = NO_IOMMU, idx = 0;
     76
     77	while (!of_parse_phandle_with_args(master_np, "iommus",
     78					   "#iommu-cells",
     79					   idx, &iommu_spec)) {
     80		err = of_iommu_xlate(dev, &iommu_spec);
     81		of_node_put(iommu_spec.np);
     82		idx++;
     83		if (err)
     84			break;
     85	}
     86
     87	return err;
     88}
     89
     90struct of_pci_iommu_alias_info {
     91	struct device *dev;
     92	struct device_node *np;
     93};
     94
     95static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
     96{
     97	struct of_pci_iommu_alias_info *info = data;
     98	u32 input_id = alias;
     99
    100	return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
    101}
    102
    103static int of_iommu_configure_device(struct device_node *master_np,
    104				     struct device *dev, const u32 *id)
    105{
    106	return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
    107		      of_iommu_configure_dev(master_np, dev);
    108}
    109
    110const struct iommu_ops *of_iommu_configure(struct device *dev,
    111					   struct device_node *master_np,
    112					   const u32 *id)
    113{
    114	const struct iommu_ops *ops = NULL;
    115	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
    116	int err = NO_IOMMU;
    117
    118	if (!master_np)
    119		return NULL;
    120
    121	if (fwspec) {
    122		if (fwspec->ops)
    123			return fwspec->ops;
    124
    125		/* In the deferred case, start again from scratch */
    126		iommu_fwspec_free(dev);
    127	}
    128
    129	/*
    130	 * We don't currently walk up the tree looking for a parent IOMMU.
    131	 * See the `Notes:' section of
    132	 * Documentation/devicetree/bindings/iommu/iommu.txt
    133	 */
    134	if (dev_is_pci(dev)) {
    135		struct of_pci_iommu_alias_info info = {
    136			.dev = dev,
    137			.np = master_np,
    138		};
    139
    140		pci_request_acs();
    141		err = pci_for_each_dma_alias(to_pci_dev(dev),
    142					     of_pci_iommu_init, &info);
    143	} else {
    144		err = of_iommu_configure_device(master_np, dev, id);
    145	}
    146
    147	/*
    148	 * Two success conditions can be represented by non-negative err here:
    149	 * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons
    150	 *  0 : we found an IOMMU, and dev->fwspec is initialised appropriately
    151	 * <0 : any actual error
    152	 */
    153	if (!err) {
    154		/* The fwspec pointer changed, read it again */
    155		fwspec = dev_iommu_fwspec_get(dev);
    156		ops    = fwspec->ops;
    157	}
    158	/*
    159	 * If we have reason to believe the IOMMU driver missed the initial
    160	 * probe for dev, replay it to get things in order.
    161	 */
    162	if (!err && dev->bus && !device_iommu_mapped(dev))
    163		err = iommu_probe_device(dev);
    164
    165	/* Ignore all other errors apart from EPROBE_DEFER */
    166	if (err == -EPROBE_DEFER) {
    167		ops = ERR_PTR(err);
    168	} else if (err < 0) {
    169		dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
    170		ops = NULL;
    171	}
    172
    173	return ops;
    174}