| commit 0dda4d7a8d071c58aa22268fd784869b28b5381b |
| Author: Bjorn Helgaas <bjorn.helgaas@hp.com> |
| Date: Fri Nov 19 16:25:39 2010 -0700 |
| |
| x86/PCI: never allocate PCI space from the last 1M below 4G |
| |
| The last 1M before 4G contains the processor restart vector and usually |
| the system ROM. We don't know the actual ROM size; I chose 1M because |
| that's how much Windows 7 appears to avoid. |
| |
| Without this check, we can allocate PCI space that will never work. On |
| Matthew's HP 2530p, we put the Intel GTT "Flush Page" at the very last |
| page, which causes a spontaneous power-off: |
| |
| pci_root PNP0A08:00: host bridge window [mem 0xfee01000-0xffffffff] |
| fffff000-ffffffff : Intel Flush Page (assigned by intel-gtt) |
| |
| Reference: https://bugzilla.kernel.org/show_bug.cgi?id=23542 |
| Reported-by: Matthew Garrett <mjg@redhat.com> |
| Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> |
| |
| diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h |
| index 5be1542..c1e908f 100644 |
| |
| |
| @@ -72,6 +72,9 @@ struct e820map { |
| #define BIOS_BEGIN 0x000a0000 |
| #define BIOS_END 0x00100000 |
| |
| +#define BIOS_ROM_BASE 0xfff00000 |
| +#define BIOS_ROM_END 0x100000000ULL |
| + |
| #ifdef __KERNEL__ |
| /* see comment in arch/x86/kernel/e820.c */ |
| extern struct e820map e820; |
| diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c |
| index c4bb261..6890241 100644 |
| |
| |
| @@ -65,8 +65,14 @@ 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 = round_down(res->end - size + 1, align); |
| + resource_size_t start, end = res->end; |
| |
| + /* Make sure we don't allocate from the last 1M before 4G */ |
| + if (res->flags & IORESOURCE_MEM) { |
| + if (end >= BIOS_ROM_BASE && end < BIOS_ROM_END) |
| + end = BIOS_ROM_BASE - 1; |
| + } |
| + start = round_down(end - size + 1, align); |
| if (res->flags & IORESOURCE_IO) { |
| |
| /* |
| @@ -80,6 +86,8 @@ pcibios_align_resource(void *data, const struct resource *res, |
| } else if (res->flags & IORESOURCE_MEM) { |
| if (start < BIOS_END) |
| start = res->end; /* fail; no space */ |
| + if (start >= BIOS_ROM_BASE && start < BIOS_ROM_END) |
| + start = ALIGN(BIOS_ROM_END, align); |
| } |
| return start; |
| } |