Re: [PATCH] PPC: PCI: Fix pcibios_io_space_offset() so it works for 32-bit ptr/64-bit rsrcs
flat view
From: Scott Wood <hidden>
Date: 2012-06-06 21:15:40
On 06/05/2012 10:50 PM, Ben Collins wrote:
The commit introducing pcibios_io_space_offset() was ignoring 32-bit to 64-bit sign extention, which is the case on ppc32 with 64-bit resource addresses. This only seems to have shown up while running under QEMU for e500mc target. It may or may be suboptimal that QEMU has an IO base address > 32-bits for the e500-pci implementation, but 1) it's still a regression and 2) it's more correct to handle things this way.
Where do you see addresses over 32 bits in QEMU's e500-pci, at least with current mainline QEMU and the mpc8544ds model? I/O space should be at 0xe1000000. I'm also not sure what this has to do with the virtual address returned by ioremap().
quoted hunk ↗ jump to hunk
Signed-off-by: Ben Collins <redacted> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- arch/powerpc/kernel/pci-common.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c index 8e78e93..be9ced7 100644 --- a/arch/powerpc/kernel/pci-common.c +++ b/arch/powerpc/kernel/pci-common.c@@ -1477,9 +1477,15 @@ int pcibios_enable_device(struct pci_dev *dev, int mask) return pci_enable_resources(dev, mask); } +/* Before assuming too much here, take care to realize that we need sign + * extension from 32-bit pointers to 64-bit resource addresses to work. + */ resource_size_t pcibios_io_space_offset(struct pci_controller *hose) { - return (unsigned long) hose->io_base_virt - _IO_BASE; + long vbase = (long)hose->io_base_virt; + long io_base = _IO_BASE; + + return (resource_size_t)(vbase - io_base);
Why do we want sign extension here? If we do want it, there are a lot of other places in this file where the same calculation is done. -Scott