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authorLee Leahy <leroy.p.leahy@intel.com>2014-12-17 13:05:26 -0800
committerPatrick Georgi <pgeorgi@google.com>2015-04-09 21:44:33 +0200
commite32b6e71967c4a8deaa31955dc49009631d1f495 (patch)
tree20cbd5d0521bb2aa67d309d779b8ffbf5a2975bd /payloads
parente9e1d7ab979b22f036ee423cc760561cd8cf1d62 (diff)
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libpayload: PCI bus scan - Eliminate endless loop
Don't attempt to scan the PCI bus if the bridge is disabled. When the PCI bridge is not setup and enabled, it is possible for the secondary bus register to contain the value zero (0). In this case the usb_scan_pci_bus routine gets into an infinite recursive loop which ends only when the heap or stack is exhausted. This patch verifies that the PCI bridge is enabled by verifying that it is enabled for either memory or I/O operations. When enabled, the secondary bus is scanned. BRANCH=none BUG=None TEST=Build and run on Samus Change-Id: I6826dc1d73b7c24729de5ac7c4d3534922ca73c5 Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: 63d04b47934761351b54c847a2692bdef81ce54f Original-Change-Id: I855240c52fa3eba841e6754816ebbcb824abc4cd Original-Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com> Original-Reviewed-on: https://chromium-review.googlesource.com/236382 Original-Commit-Queue: Leroy P Leahy <leroy.p.leahy@intel.com> Original-Tested-by: Leroy P Leahy <leroy.p.leahy@intel.com> Original-Reviewed-by: Giri P Mudusuru <giri.p.mudusuru@intel.com> Original-Reviewed-by: Duncan Laurie <dlaurie@chromium.org> Reviewed-on: http://review.coreboot.org/8734 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Diffstat (limited to 'payloads')
-rw-r--r--payloads/libpayload/drivers/usb/usbinit.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/payloads/libpayload/drivers/usb/usbinit.c b/payloads/libpayload/drivers/usb/usbinit.c
index 6fb7d4b11..4225c3f15 100644
--- a/payloads/libpayload/drivers/usb/usbinit.c
+++ b/payloads/libpayload/drivers/usb/usbinit.c
@@ -146,9 +146,13 @@ static void usb_scan_pci_bus(int bus)
header_type = pci_read_config8(pci_device, REG_HEADER_TYPE);
/* If this is a bridge, scan the other side. */
if ((header_type & ~HEADER_TYPE_MULTIFUNCTION) ==
- HEADER_TYPE_BRIDGE)
- usb_scan_pci_bus(pci_read_config8(pci_device,
- REG_SECONDARY_BUS));
+ HEADER_TYPE_BRIDGE) {
+ /* Verify that the bridge is enabled */
+ if ((pci_read_config16(pci_device, REG_COMMAND)
+ & 3) != 0)
+ usb_scan_pci_bus(pci_read_config8(
+ pci_device, REG_SECONDARY_BUS));
+ }
else
usb_controller_initialize(bus, dev, func);
}