[PATCH 3.14 18/73] PCI: Support 64-bit bridge windows if we have 64-bit dma_addr_t

Greg Kroah-Hartman
2014-12-05T23:30:18Z

From: Yinghai Lu <yinghai@kernel.org>

commit 7fc986d8a9727e5d40da3c2c1c343da6142e82a9 upstream.

Aaron reported that a 32-bit x86 kernel with Physical Address Extension
(PAE) support complains about bridge prefetchable memory windows above 4GB:

pci_bus 0000:00: root bus resource [mem 0x380000000000-0x383fffffffff]
...
pci 0000:03:00.0: reg 0x10: [mem 0x383fffc00000-0x383fffdfffff 64bit pref]
pci 0000:03:00.0: reg 0x20: [mem 0x383fffe04000-0x383fffe07fff 64bit pref]
pci 0000:03:00.1: reg 0x10: [mem 0x383fffa00000-0x383fffbfffff 64bit pref]
pci 0000:03:00.1: reg 0x20: [mem 0x383fffe00000-0x383fffe03fff 64bit pref]
pci 0000:00:02.2: PCI bridge to [bus 03-04]
pci 0000:00:02.2: bridge window [io 0x1000-0x1fff]
pci 0000:00:02.2: bridge window [mem 0x91900000-0x91cfffff]
pci 0000:00:02.2: can't handle 64-bit address space for bridge

In this kernel, unsigned long is 32 bits and dma_addr_t is 64 bits.
Previously we used "unsigned long" to hold the bridge window address. But
this is a bus address, so we should use dma_addr_t instead.

Use dma_addr_t to hold the bridge window base and limit.

The question of whether the CPU can actually *address* the window is
separate and depends on what the physical address space of the CPU is and
whether the host bridge does any address translation.

[bhelgaas: fix "shift count > width of type", changelog, stable tag]
Fixes: d56dbf5bab8c ("PCI: Allocate 64-bit BARs above 4G when possible")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=88131
Reported-by: Aaron Ma <mapengyu@gmail.com>
Tested-by: Aaron Ma <mapengyu@gmail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/pci/probe.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)

--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -395,15 +395,16 @@ static void pci_read_bridge_mmio_pref(st
{
struct pci_dev *dev = child->self;
u16 mem_base_lo, mem_limit_lo;
- unsigned long base, limit;
+ u64 base64, limit64;
+ dma_addr_t base, limit;
struct pci_bus_region region;
struct resource *res;

res = child->resource[2];
pci_read_config_word(dev, PCI_PREF_MEMORY_BASE, &mem_base_lo);
pci_read_config_word(dev, PCI_PREF_MEMORY_LIMIT, &mem_limit_lo);
- base = ((unsigned long) mem_base_lo & PCI_PREF_RANGE_MASK) << 16;
- limit = ((unsigned long) mem_limit_lo & PCI_PREF_RANGE_MASK) << 16;
+ base64 = (mem_base_lo & PCI_PREF_RANGE_MASK) << 16;
+ limit64 = (mem_limit_lo & PCI_PREF_RANGE_MASK) << 16;

if ((mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) == PCI_PREF_RANGE_TYPE_64) {
u32 mem_base_hi, mem_limit_hi;
@@ -417,18 +418,20 @@ static void pci_read_bridge_mmio_pref(st
* this, just assume they are not being used.
*/
if (mem_base_hi <= mem_limit_hi) {
-#if BITS_PER_LONG == 64
- base |= ((unsigned long) mem_base_hi) << 32;
- limit |= ((unsigned long) mem_limit_hi) << 32;
-#else
- if (mem_base_hi || mem_limit_hi) {
- dev_err(&dev->dev, "can't handle 64-bit "
- "address space for bridge\n");
- return;
- }
-#endif
+ base64 |= (u64) mem_base_hi << 32;
+ limit64 |= (u64) mem_limit_hi << 32;
}
}
+
+ base = (dma_addr_t) base64;
+ limit = (dma_addr_t) limit64;
+
+ if (base != base64) {
+ dev_err(&dev->dev, "can't handle bridge window above 4GB (bus address %#010llx)\n",
+ (unsigned long long) base64);
+ return;
+ }
+
if (base <= limit) {
res->flags = (mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) |
IORESOURCE_MEM | IORESOURCE_PREFETCH;