On Thu, Jan 11, 2018 at 02:23:30PM +0100, Christian König wrote: > 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 If you can supply a section number, I'll add it here. That spec is 700 pages, so a hint would be useful. > 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 >
