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remarkable-linux/drivers/pci/setup-res.c
Bjorn Helgaas 9aac537e0e PCI: disable MEM decoding while updating 64-bit MEM BARs 
When we update 64-bit BARs, we have to perform two config writes.  Between
the writes, the half-written BAR value could match a MEM access intended
for another device.  This could result in corruption of this device (for
writes) or an unexpected response machine check (for reads).

To prevent this, disable MEM decoding while updating such BARs.  This uses
the same safety test as 253d2e5498, which disables both MEM and IO while
sizing BARs, namely, we don't disable decoding for host bridge devices.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2012-07-09 19:50:53 -06:00

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8.8 KiB
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/*
* drivers/pci/setup-res.c
*
* Extruded from code written by
* Dave Rusling (david.rusling@reo.mts.dec.com)
* David Mosberger (davidm@cs.arizona.edu)
* David Miller (davem@redhat.com)
*
* Support routines for initializing a PCI subsystem.
*/
/* fixed for multiple pci buses, 1999 Andrea Arcangeli <andrea@suse.de> */
/*
* Nov 2000, Ivan Kokshaysky <ink@jurassic.park.msu.ru>
* Resource sorting
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/pci.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/cache.h>
#include <linux/slab.h>
#include "pci.h"
void pci_update_resource(struct pci_dev *dev, int resno)
{
struct pci_bus_region region;
bool disable;
u16 cmd;
u32 new, check, mask;
int reg;
enum pci_bar_type type;
struct resource *res = dev->resource + resno;
/*
* Ignore resources for unimplemented BARs and unused resource slots
* for 64 bit BARs.
*/
if (!res->flags)
return;
/*
* Ignore non-moveable resources. This might be legacy resources for
* which no functional BAR register exists or another important
* system resource we shouldn't move around.
*/
if (res->flags & IORESOURCE_PCI_FIXED)
return;
pcibios_resource_to_bus(dev, &region, res);
new = region.start | (res->flags & PCI_REGION_FLAG_MASK);
if (res->flags & IORESOURCE_IO)
mask = (u32)PCI_BASE_ADDRESS_IO_MASK;
else
mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;
reg = pci_resource_bar(dev, resno, &type);
if (!reg)
return;
if (type != pci_bar_unknown) {
if (!(res->flags & IORESOURCE_ROM_ENABLE))
return;
new |= PCI_ROM_ADDRESS_ENABLE;
}
/*
* We can't update a 64-bit BAR atomically, so when possible,
* disable decoding so that a half-updated BAR won't conflict
* with another device.
*/
disable = (res->flags & IORESOURCE_MEM_64) && !dev->mmio_always_on;
if (disable) {
pci_read_config_word(dev, PCI_COMMAND, &cmd);
pci_write_config_word(dev, PCI_COMMAND,
cmd & ~PCI_COMMAND_MEMORY);
}
pci_write_config_dword(dev, reg, new);
pci_read_config_dword(dev, reg, &check);
if ((new ^ check) & mask) {
dev_err(&dev->dev, "BAR %d: error updating (%#08x != %#08x)\n",
resno, new, check);
}
if (res->flags & IORESOURCE_MEM_64) {
new = region.start >> 16 >> 16;
pci_write_config_dword(dev, reg + 4, new);
pci_read_config_dword(dev, reg + 4, &check);
if (check != new) {
dev_err(&dev->dev, "BAR %d: error updating "
"(high %#08x != %#08x)\n", resno, new, check);
}
}
if (disable)
pci_write_config_word(dev, PCI_COMMAND, cmd);
res->flags &= ~IORESOURCE_UNSET;
dev_dbg(&dev->dev, "BAR %d: set to %pR (PCI address [%#llx-%#llx])\n",
resno, res, (unsigned long long)region.start,
(unsigned long long)region.end);
}
int pci_claim_resource(struct pci_dev *dev, int resource)
{
struct resource *res = &dev->resource[resource];
struct resource *root, *conflict;
root = pci_find_parent_resource(dev, res);
if (!root) {
dev_info(&dev->dev, "no compatible bridge window for %pR\n",
res);
return -EINVAL;
}
conflict = request_resource_conflict(root, res);
if (conflict) {
dev_info(&dev->dev,
"address space collision: %pR conflicts with %s %pR\n",
res, conflict->name, conflict);
return -EBUSY;
}
return 0;
}
EXPORT_SYMBOL(pci_claim_resource);
void pci_disable_bridge_window(struct pci_dev *dev)
{
dev_info(&dev->dev, "disabling bridge mem windows\n");
/* MMIO Base/Limit */
pci_write_config_dword(dev, PCI_MEMORY_BASE, 0x0000fff0);
/* Prefetchable MMIO Base/Limit */
pci_write_config_dword(dev, PCI_PREF_LIMIT_UPPER32, 0);
pci_write_config_dword(dev, PCI_PREF_MEMORY_BASE, 0x0000fff0);
pci_write_config_dword(dev, PCI_PREF_BASE_UPPER32, 0xffffffff);
}
static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
int resno, resource_size_t size, resource_size_t align)
{
struct resource *res = dev->resource + resno;
resource_size_t min;
int ret;
min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
/* First, try exact prefetching match.. */
ret = pci_bus_alloc_resource(bus, res, size, align, min,
IORESOURCE_PREFETCH,
pcibios_align_resource, dev);
if (ret < 0 && (res->flags & IORESOURCE_PREFETCH)) {
/*
* That failed.
*
* But a prefetching area can handle a non-prefetching
* window (it will just not perform as well).
*/
ret = pci_bus_alloc_resource(bus, res, size, align, min, 0,
pcibios_align_resource, dev);
}
return ret;
}
/*
* Generic function that returns a value indicating that the device's
* original BIOS BAR address was not saved and so is not available for
* reinstatement.
*
* Can be over-ridden by architecture specific code that implements
* reinstatement functionality rather than leaving it disabled when
* normal allocation attempts fail.
*/
resource_size_t __weak pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx)
{
return 0;
}
static int pci_revert_fw_address(struct resource *res, struct pci_dev *dev,
int resno, resource_size_t size)
{
struct resource *root, *conflict;
resource_size_t fw_addr, start, end;
int ret = 0;
fw_addr = pcibios_retrieve_fw_addr(dev, resno);
if (!fw_addr)
return 1;
start = res->start;
end = res->end;
res->start = fw_addr;
res->end = res->start + size - 1;
root = pci_find_parent_resource(dev, res);
if (!root) {
if (res->flags & IORESOURCE_IO)
root = &ioport_resource;
else
root = &iomem_resource;
}
dev_info(&dev->dev, "BAR %d: trying firmware assignment %pR\n",
resno, res);
conflict = request_resource_conflict(root, res);
if (conflict) {
dev_info(&dev->dev,
"BAR %d: %pR conflicts with %s %pR\n", resno,
res, conflict->name, conflict);
res->start = start;
res->end = end;
ret = 1;
}
return ret;
}
static int _pci_assign_resource(struct pci_dev *dev, int resno, int size, resource_size_t min_align)
{
struct resource *res = dev->resource + resno;
struct pci_bus *bus;
int ret;
char *type;
bus = dev->bus;
while ((ret = __pci_assign_resource(bus, dev, resno, size, min_align))) {
if (!bus->parent || !bus->self->transparent)
break;
bus = bus->parent;
}
if (ret) {
if (res->flags & IORESOURCE_MEM)
if (res->flags & IORESOURCE_PREFETCH)
type = "mem pref";
else
type = "mem";
else if (res->flags & IORESOURCE_IO)
type = "io";
else
type = "unknown";
dev_info(&dev->dev,
"BAR %d: can't assign %s (size %#llx)\n",
resno, type, (unsigned long long) resource_size(res));
}
return ret;
}
int pci_reassign_resource(struct pci_dev *dev, int resno, resource_size_t addsize,
resource_size_t min_align)
{
struct resource *res = dev->resource + resno;
resource_size_t new_size;
int ret;
if (!res->parent) {
dev_info(&dev->dev, "BAR %d: can't reassign an unassigned resource %pR "
"\n", resno, res);
return -EINVAL;
}
/* already aligned with min_align */
new_size = resource_size(res) + addsize;
ret = _pci_assign_resource(dev, resno, new_size, min_align);
if (!ret) {
res->flags &= ~IORESOURCE_STARTALIGN;
dev_info(&dev->dev, "BAR %d: reassigned %pR\n", resno, res);
if (resno < PCI_BRIDGE_RESOURCES)
pci_update_resource(dev, resno);
}
return ret;
}
int pci_assign_resource(struct pci_dev *dev, int resno)
{
struct resource *res = dev->resource + resno;
resource_size_t align, size;
struct pci_bus *bus;
int ret;
align = pci_resource_alignment(dev, res);
if (!align) {
dev_info(&dev->dev, "BAR %d: can't assign %pR "
"(bogus alignment)\n", resno, res);
return -EINVAL;
}
bus = dev->bus;
size = resource_size(res);
ret = _pci_assign_resource(dev, resno, size, align);
/*
* If we failed to assign anything, let's try the address
* where firmware left it. That at least has a chance of
* working, which is better than just leaving it disabled.
*/
if (ret < 0)
ret = pci_revert_fw_address(res, dev, resno, size);
if (!ret) {
res->flags &= ~IORESOURCE_STARTALIGN;
dev_info(&dev->dev, "BAR %d: assigned %pR\n", resno, res);
if (resno < PCI_BRIDGE_RESOURCES)
pci_update_resource(dev, resno);
}
return ret;
}
int pci_enable_resources(struct pci_dev *dev, int mask)
{
u16 cmd, old_cmd;
int i;
struct resource *r;
pci_read_config_word(dev, PCI_COMMAND, &cmd);
old_cmd = cmd;
for (i = 0; i < PCI_NUM_RESOURCES; i++) {
if (!(mask & (1 << i)))
continue;
r = &dev->resource[i];
if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
continue;
if ((i == PCI_ROM_RESOURCE) &&
(!(r->flags & IORESOURCE_ROM_ENABLE)))
continue;
if (!r->parent) {
dev_err(&dev->dev, "device not available "
"(can't reserve %pR)\n", r);
return -EINVAL;
}
if (r->flags & IORESOURCE_IO)
cmd |= PCI_COMMAND_IO;
if (r->flags & IORESOURCE_MEM)
cmd |= PCI_COMMAND_MEMORY;
}
if (cmd != old_cmd) {
dev_info(&dev->dev, "enabling device (%04x -> %04x)\n",
old_cmd, cmd);
pci_write_config_word(dev, PCI_COMMAND, cmd);
}
return 0;
}
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