From dc9887dc02e37bcf83f4e792aa14b07782ef54cf Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Tue, 26 Oct 2010 15:41:44 -0600 Subject: x86/PCI: allocate space from the end of a region, not the beginning Allocate from the end of a region, not the beginning. For example, if we need to allocate 0x800 bytes for a device on bus 0000:00 given these resources: [mem 0xbff00000-0xdfffffff] PCI Bus 0000:00 [mem 0xc0000000-0xdfffffff] PCI Bus 0000:02 the available space at [mem 0xbff00000-0xbfffffff] is passed to the alignment callback (pcibios_align_resource()). Prior to this patch, we would put the new 0x800 byte resource at the beginning of that available space, i.e., at [mem 0xbff00000-0xbff007ff]. With this patch, we put it at the end, at [mem 0xbffff800-0xbfffffff]. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=16228#c41 Signed-off-by: Bjorn Helgaas Signed-off-by: Jesse Barnes --- arch/x86/pci/i386.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'arch/x86/pci/i386.c') diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c index 55253095be8..826140af3c3 100644 --- a/arch/x86/pci/i386.c +++ b/arch/x86/pci/i386.c @@ -65,16 +65,21 @@ pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; - resource_size_t start = res->start; + resource_size_t start = round_down(res->end - size + 1, align); if (res->flags & IORESOURCE_IO) { - if (skip_isa_ioresource_align(dev)) - return start; - if (start & 0x300) - start = (start + 0x3ff) & ~0x3ff; + + /* + * If we're avoiding ISA aliases, the largest contiguous I/O + * port space is 256 bytes. Clearing bits 9 and 10 preserves + * all 256-byte and smaller alignments, so the result will + * still be correctly aligned. + */ + if (!skip_isa_ioresource_align(dev)) + start &= ~0x300; } else if (res->flags & IORESOURCE_MEM) { if (start < BIOS_END) - start = BIOS_END; + start = res->end; /* fail; no space */ } return start; } -- cgit v1.2.3-18-g5258