Avoid problems with BIOS implementations which don't report all used resources to the OS by only allocating a 256GB window directly below the hardware limit. For the full hardware documentation see: https://support.amd.com/TechDocs/49125_15h_Models_30h-3Fh_BKDG.pdf Fixes a silent reboot loop reported by Aaro Koskinen <aaro.koskinen@xxxxxx> on an AMD-based MSI MS-7699/760GA-P43(FX) system. v2: cleanup code a bit more, update comment and explain the hw limit v3: improve commit message Link: https://lkml.kernel.org/r/20180105220412.fzpwqe4zljdawr36@xxxxxxxxxxxxxxxxxxxxxxxxx Reported-by: Aaro Koskinen <aaro.koskinen@xxxxxx> Signed-off-by: Christian König <christian.koenig@xxxxxxx> --- arch/x86/pci/fixup.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c index a91280da2ea1..9c1c98d7e3a7 100644 --- a/arch/x86/pci/fixup.c +++ b/arch/x86/pci/fixup.c @@ -662,10 +662,11 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2033, quirk_no_aersid); */ static void pci_amd_enable_64bit_bar(struct pci_dev *dev) { - unsigned i; u32 base, limit, high; - struct resource *res, *conflict; struct pci_dev *other; + struct resource *res; + unsigned i; + int r; if (!(pci_probe & PCI_BIG_ROOT_WINDOW)) return; @@ -702,19 +703,17 @@ static void pci_amd_enable_64bit_bar(struct pci_dev *dev) if (!res) return; + /* Allocate a 256GB window directly below the 0xfd00000000 hw limit */ res->name = "PCI Bus 0000:00"; res->flags = IORESOURCE_PREFETCH | IORESOURCE_MEM | IORESOURCE_MEM_64 | IORESOURCE_WINDOW; - res->start = 0x100000000ull; + res->start = 0xbd00000000ull; res->end = 0xfd00000000ull - 1; - /* Just grab the free area behind system memory for this */ - while ((conflict = request_resource_conflict(&iomem_resource, res))) { - if (conflict->end >= res->end) { - kfree(res); - return; - } - res->start = conflict->end + 1; + r = request_resource(&iomem_resource, res); + if (r) { + kfree(res); + return; } dev_info(&dev->dev, "adding root bus resource %pR\n", res); -- 2.11.0
