diff options
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 108 |
1 files changed, 82 insertions, 26 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 2f8f0f516305..2363922b3b95 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5036,6 +5036,11 @@ void pci_ignore_hotplug(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_ignore_hotplug); +resource_size_t __weak pcibios_default_alignment(void) +{ + return 0; +} + #define RESOURCE_ALIGNMENT_PARAM_SIZE COMMAND_LINE_SIZE static char resource_alignment_param[RESOURCE_ALIGNMENT_PARAM_SIZE] = {0}; static DEFINE_SPINLOCK(resource_alignment_lock); @@ -5043,22 +5048,25 @@ static DEFINE_SPINLOCK(resource_alignment_lock); /** * pci_specified_resource_alignment - get resource alignment specified by user. * @dev: the PCI device to get + * @resize: whether or not to change resources' size when reassigning alignment * * RETURNS: Resource alignment if it is specified. * Zero if it is not specified. */ -static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) +static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, + bool *resize) { int seg, bus, slot, func, align_order, count; unsigned short vendor, device, subsystem_vendor, subsystem_device; - resource_size_t align = 0; + resource_size_t align = pcibios_default_alignment(); char *p; spin_lock(&resource_alignment_lock); p = resource_alignment_param; - if (!*p) + if (!*p && !align) goto out; if (pci_has_flag(PCI_PROBE_ONLY)) { + align = 0; pr_info_once("PCI: Ignoring requested alignments (PCI_PROBE_ONLY)\n"); goto out; } @@ -5088,6 +5096,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) (!device || (device == dev->device)) && (!subsystem_vendor || (subsystem_vendor == dev->subsystem_vendor)) && (!subsystem_device || (subsystem_device == dev->subsystem_device))) { + *resize = true; if (align_order == -1) align = PAGE_SIZE; else @@ -5113,6 +5122,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) bus == dev->bus->number && slot == PCI_SLOT(dev->devfn) && func == PCI_FUNC(dev->devfn)) { + *resize = true; if (align_order == -1) align = PAGE_SIZE; else @@ -5132,6 +5142,68 @@ out: return align; } +static void pci_request_resource_alignment(struct pci_dev *dev, int bar, + resource_size_t align, bool resize) +{ + struct resource *r = &dev->resource[bar]; + resource_size_t size; + + if (!(r->flags & IORESOURCE_MEM)) + return; + + if (r->flags & IORESOURCE_PCI_FIXED) { + dev_info(&dev->dev, "BAR%d %pR: ignoring requested alignment %#llx\n", + bar, r, (unsigned long long)align); + return; + } + + size = resource_size(r); + if (size >= align) + return; + + /* + * Increase the alignment of the resource. There are two ways we + * can do this: + * + * 1) Increase the size of the resource. BARs are aligned on their + * size, so when we reallocate space for this resource, we'll + * allocate it with the larger alignment. This also prevents + * assignment of any other BARs inside the alignment region, so + * if we're requesting page alignment, this means no other BARs + * will share the page. + * + * The disadvantage is that this makes the resource larger than + * the hardware BAR, which may break drivers that compute things + * based on the resource size, e.g., to find registers at a + * fixed offset before the end of the BAR. + * + * 2) Retain the resource size, but use IORESOURCE_STARTALIGN and + * set r->start to the desired alignment. By itself this + * doesn't prevent other BARs being put inside the alignment + * region, but if we realign *every* resource of every device in + * the system, none of them will share an alignment region. + * + * When the user has requested alignment for only some devices via + * the "pci=resource_alignment" argument, "resize" is true and we + * use the first method. Otherwise we assume we're aligning all + * devices and we use the second. + */ + + dev_info(&dev->dev, "BAR%d %pR: requesting alignment to %#llx\n", + bar, r, (unsigned long long)align); + + if (resize) { + r->start = 0; + r->end = align - 1; + } else { + r->flags &= ~IORESOURCE_SIZEALIGN; + r->flags |= IORESOURCE_STARTALIGN; + r->start = align; + r->end = r->start + size - 1; + } + r->flags |= IORESOURCE_UNSET; +} + /* * This function disables memory decoding and releases memory resources * of the device specified by kernel's boot parameter 'pci=resource_alignment='. @@ -5143,8 +5215,9 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) { int i; struct resource *r; - resource_size_t align, size; + resource_size_t align; u16 command; + bool resize = false; /* * VF BARs are read-only zero according to SR-IOV spec r1.1, sec @@ -5156,7 +5229,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) return; /* check if specified PCI is target device to reassign */ - align = pci_specified_resource_alignment(dev); + align = pci_specified_resource_alignment(dev, &resize); if (!align) return; @@ -5173,28 +5246,11 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) command &= ~PCI_COMMAND_MEMORY; pci_write_config_word(dev, PCI_COMMAND, command); - for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) { - r = &dev->resource[i]; - if (!(r->flags & IORESOURCE_MEM)) - continue; - if (r->flags & IORESOURCE_PCI_FIXED) { - dev_info(&dev->dev, "Ignoring requested alignment for BAR%d: %pR\n", - i, r); - continue; - } + for (i = 0; i <= PCI_ROM_RESOURCE; i++) + pci_request_resource_alignment(dev, i, align, resize); - size = resource_size(r); - if (size < align) { - size = align; - dev_info(&dev->dev, - "Rounding up size of resource #%d to %#llx.\n", - i, (unsigned long long)size); - } - r->flags |= IORESOURCE_UNSET; - r->end = size - 1; - r->start = 0; - } - /* Need to disable bridge's resource window, + /* + * Need to disable bridge's resource window, * to enable the kernel to reassign new resource * window later on. */ |