Am 11.01.2018 um 15:21 schrieb Bjorn Helgaas:
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.
Sorry, had to search for that as well. That is noted in section "2.4.6
System Address Map".
Do you want to add that or should I resend the patch?
Regards,
Christian.
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
