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e7708f5b10
Add ECAM-related constants to provide a set of standard constants defining memory address shift values to the byte-level address that can be used to access the PCI Express Configuration Space, and then move native PCI Express controller drivers to use the newly introduced definitions retiring driver-specific ones. Refactor pci_ecam_map_bus() function to use newly added constants so that limits to the bus, device function and offset (now limited to 4K as per the specification) are in place to prevent the defective or malicious caller from supplying incorrect configuration offset and thus targeting the wrong device when accessing extended configuration space. This refactor also allows for the ".bus_shift" initialisers to be dropped when the user is not using a custom value as a default value will be used as per the PCI Express Specification. Thanks to Qian Cai <qcai@redhat.com>, Michael Walle <michael@walle.cc>, and Vladimir Oltean <olteanv@gmail.com> for reporting a pci_ecam_create() issue with .bus_shift and to Vladimir for proposing the fix. [bhelgaas: incorporate Vladimir's fix, update commit log] Suggested-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/20201129230743.3006978-2-kw@linux.com Tested-by: Michael Walle <michael@walle.cc> Signed-off-by: Krzysztof Wilczyński <kw@linux.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Jon Derrick <jonathan.derrick@intel.com> Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
196 lines
4.8 KiB
C
196 lines
4.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2016 Broadcom
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*/
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#include <linux/device.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/pci-ecam.h>
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#include <linux/slab.h>
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/*
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* On 64-bit systems, we do a single ioremap for the whole config space
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* since we have enough virtual address range available. On 32-bit, we
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* ioremap the config space for each bus individually.
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*/
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static const bool per_bus_mapping = !IS_ENABLED(CONFIG_64BIT);
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/*
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* Create a PCI config space window
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* - reserve mem region
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* - alloc struct pci_config_window with space for all mappings
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* - ioremap the config space
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*/
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struct pci_config_window *pci_ecam_create(struct device *dev,
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struct resource *cfgres, struct resource *busr,
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const struct pci_ecam_ops *ops)
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{
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unsigned int bus_shift = ops->bus_shift;
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struct pci_config_window *cfg;
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unsigned int bus_range, bus_range_max, bsz;
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struct resource *conflict;
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int i, err;
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if (busr->start > busr->end)
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return ERR_PTR(-EINVAL);
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cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
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if (!cfg)
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return ERR_PTR(-ENOMEM);
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/* ECAM-compliant platforms need not supply ops->bus_shift */
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if (!bus_shift)
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bus_shift = PCIE_ECAM_BUS_SHIFT;
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cfg->parent = dev;
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cfg->ops = ops;
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cfg->busr.start = busr->start;
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cfg->busr.end = busr->end;
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cfg->busr.flags = IORESOURCE_BUS;
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bus_range = resource_size(&cfg->busr);
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bus_range_max = resource_size(cfgres) >> bus_shift;
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if (bus_range > bus_range_max) {
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bus_range = bus_range_max;
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cfg->busr.end = busr->start + bus_range - 1;
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dev_warn(dev, "ECAM area %pR can only accommodate %pR (reduced from %pR desired)\n",
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cfgres, &cfg->busr, busr);
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}
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bsz = 1 << bus_shift;
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cfg->res.start = cfgres->start;
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cfg->res.end = cfgres->end;
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cfg->res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
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cfg->res.name = "PCI ECAM";
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conflict = request_resource_conflict(&iomem_resource, &cfg->res);
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if (conflict) {
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err = -EBUSY;
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dev_err(dev, "can't claim ECAM area %pR: address conflict with %s %pR\n",
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&cfg->res, conflict->name, conflict);
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goto err_exit;
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}
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if (per_bus_mapping) {
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cfg->winp = kcalloc(bus_range, sizeof(*cfg->winp), GFP_KERNEL);
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if (!cfg->winp)
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goto err_exit_malloc;
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for (i = 0; i < bus_range; i++) {
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cfg->winp[i] =
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pci_remap_cfgspace(cfgres->start + i * bsz,
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bsz);
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if (!cfg->winp[i])
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goto err_exit_iomap;
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}
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} else {
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cfg->win = pci_remap_cfgspace(cfgres->start, bus_range * bsz);
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if (!cfg->win)
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goto err_exit_iomap;
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}
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if (ops->init) {
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err = ops->init(cfg);
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if (err)
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goto err_exit;
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}
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dev_info(dev, "ECAM at %pR for %pR\n", &cfg->res, &cfg->busr);
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return cfg;
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err_exit_iomap:
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dev_err(dev, "ECAM ioremap failed\n");
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err_exit_malloc:
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err = -ENOMEM;
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err_exit:
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pci_ecam_free(cfg);
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return ERR_PTR(err);
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}
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EXPORT_SYMBOL_GPL(pci_ecam_create);
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void pci_ecam_free(struct pci_config_window *cfg)
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{
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int i;
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if (per_bus_mapping) {
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if (cfg->winp) {
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for (i = 0; i < resource_size(&cfg->busr); i++)
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if (cfg->winp[i])
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iounmap(cfg->winp[i]);
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kfree(cfg->winp);
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}
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} else {
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if (cfg->win)
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iounmap(cfg->win);
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}
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if (cfg->res.parent)
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release_resource(&cfg->res);
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kfree(cfg);
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}
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EXPORT_SYMBOL_GPL(pci_ecam_free);
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/*
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* Function to implement the pci_ops ->map_bus method
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*/
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void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn,
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int where)
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{
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struct pci_config_window *cfg = bus->sysdata;
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unsigned int bus_shift = cfg->ops->bus_shift;
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unsigned int devfn_shift = cfg->ops->bus_shift - 8;
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unsigned int busn = bus->number;
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void __iomem *base;
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u32 bus_offset, devfn_offset;
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if (busn < cfg->busr.start || busn > cfg->busr.end)
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return NULL;
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busn -= cfg->busr.start;
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if (per_bus_mapping) {
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base = cfg->winp[busn];
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busn = 0;
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} else
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base = cfg->win;
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if (cfg->ops->bus_shift) {
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bus_offset = (busn & PCIE_ECAM_BUS_MASK) << bus_shift;
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devfn_offset = (devfn & PCIE_ECAM_DEVFN_MASK) << devfn_shift;
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where &= PCIE_ECAM_REG_MASK;
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return base + (bus_offset | devfn_offset | where);
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}
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return base + PCIE_ECAM_OFFSET(busn, devfn, where);
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}
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EXPORT_SYMBOL_GPL(pci_ecam_map_bus);
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/* ECAM ops */
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const struct pci_ecam_ops pci_generic_ecam_ops = {
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.pci_ops = {
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.map_bus = pci_ecam_map_bus,
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.read = pci_generic_config_read,
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.write = pci_generic_config_write,
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}
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};
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EXPORT_SYMBOL_GPL(pci_generic_ecam_ops);
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#if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
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/* ECAM ops for 32-bit access only (non-compliant) */
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const struct pci_ecam_ops pci_32b_ops = {
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.pci_ops = {
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.map_bus = pci_ecam_map_bus,
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.read = pci_generic_config_read32,
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.write = pci_generic_config_write32,
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}
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};
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/* ECAM ops for 32-bit read only (non-compliant) */
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const struct pci_ecam_ops pci_32b_read_ops = {
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.pci_ops = {
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.map_bus = pci_ecam_map_bus,
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.read = pci_generic_config_read32,
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.write = pci_generic_config_write,
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}
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};
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#endif
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