Timothy Pearson (tpearson@raptorengineeringinc.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/8261
-gerrit
commit 144329bd7d8f13114b0ed46c4e55f25efc0e0230 Author: Timothy Pearson tpearson@raptorengineeringinc.com Date: Fri Jan 23 20:20:56 2015 -0600
device/device.c: Correct PCI register space location
Fix the incorrect PCI register space location causing corruption with more than ~3.5GB physical RAM on AMD Family 10h systems.
Change-Id: I66d1bfa1e977a6b492c1909079087a801c7e6a3a Signed-off-by: Timothy Pearson tpearson@raptorengineeringinc.com --- src/device/device.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)
diff --git a/src/device/device.c b/src/device/device.c index 00e323a..94390b7 100644 --- a/src/device/device.c +++ b/src/device/device.c @@ -13,6 +13,7 @@ * (Written by Yinghai Lu yhlu@tyan.com for Tyan) * Copyright (C) 2005-2006 Stefan Reinauer stepan@openbios.org * Copyright (C) 2009 Myles Watson mylesgw@gmail.com + * Copyright (C) 2015 Timothy Pearson tpearson@raptorengineeringinc.com, Raptor Engineering */
/* @@ -685,6 +686,25 @@ static void constrain_resources(struct device *dev, struct constraints* limits) } }
+/* + * In this function there is a provision to shrink the potential PCI address + * space to the resource specified value. + * + * Without this the PCI address space attempts to reserve roughly all 32-bit + * addressable RAM, leading to allocation below the AMD fixed resource window + * instead of above it. When allocated below the fixed resource window it + * is not protected by the e820 map and the PCI configuration is overwritten, + * causing all PCI devices to become unusable! + * + * This bug is only exposed when the top of system RAM touches the bottom of + * the fixed resource window. If less than ~3.5GB of memory is installed there + * is a gap between system RAM and the fixed resource window which protects + * the incorrectly allocated PCI configuration registers and hides this bug. + * + * On non-AMD systems this may not matter as much, but the code below is generic + * and should not harm other systems. + */ + static void avoid_fixed_resources(struct device *dev) { struct constraints limits; @@ -712,6 +732,12 @@ static void avoid_fixed_resources(struct device *dev) if ((res->flags & MEM_MASK) == MEM_TYPE && (res->limit < limits.mem.limit)) limits.mem.limit = res->limit; + /* Shrink PCI address space */ + if ((res->flags & MEM_MASK) == MEM_TYPE && + (res->size < (limits.mem.limit - limits.mem.base + 1))) { + limits.mem.base = (limits.mem.limit - res->size + 1); + limits.mem.size = res->size; + } if ((res->flags & IO_MASK) == IO_TYPE && (res->limit < limits.io.limit)) limits.io.limit = res->limit;