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authorKornel Duleba <mindal@semihalf.com>2021-11-23 08:13:56 +0000
committerWojciech Macek <wma@FreeBSD.org>2021-11-25 08:53:40 +0000
commit68cbe189fdd3c572476f8af9219a5d335f05b51a (patch)
tree8a1565b5572e9625baff8cd8d6698f054727c1e2
parent37c03d4de3d2104336adbb67a9aa2aa681b6d042 (diff)
downloadsrc-68cbe189fdd3c572476f8af9219a5d335f05b51a.tar.gz
src-68cbe189fdd3c572476f8af9219a5d335f05b51a.zip
pci: Don't try to read cfg registers of non-existing devices
Instead of returning 0xffs some controllers, such as Layerscape generate an external exception when someone attempts to read any register of config space of a non-existing device other than PCIR_VENDOR. This causes a kernel panic. Fix it by bailing during device enumeration if a device vendor register returns invalid value. (0xffff) Use this opportunity to replace some hardcoded values with a macro. I believe that this change won't have any unintended side-effects since it is safe to assume that vendor == 0xffff -> hdr_type == 0xffff. Sponsored by: Alstom Obtained from: Semihalf Reviewed by: jhb MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D33059
-rw-r--r--sys/dev/pci/pci.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index 7493ae1727fb..ecef65477137 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -683,11 +683,12 @@ pci_read_device(device_t pcib, device_t bus, int d, int b, int s, int f)
uint16_t vid, did;
vid = REG(PCIR_VENDOR, 2);
+ if (vid == PCIV_INVALID)
+ return (NULL);
+
did = REG(PCIR_DEVICE, 2);
- if (vid != 0xffff)
- return (pci_fill_devinfo(pcib, bus, d, b, s, f, vid, did));
- return (NULL);
+ return (pci_fill_devinfo(pcib, bus, d, b, s, f, vid, did));
}
struct pci_devinfo *
@@ -4141,6 +4142,10 @@ pci_add_children(device_t dev, int domain, int busno)
pcifunchigh = 0;
f = 0;
DELAY(1);
+
+ /* If function 0 is not present, skip to the next slot. */
+ if (REG(PCIR_VENDOR, 2) == PCIV_INVALID)
+ continue;
hdrtype = REG(PCIR_HDRTYPE, 1);
if ((hdrtype & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
continue;
@@ -4182,7 +4187,7 @@ pci_rescan_method(device_t dev)
for (s = 0; s <= maxslots; s++) {
/* If function 0 is not present, skip to the next slot. */
f = 0;
- if (REG(PCIR_VENDOR, 2) == 0xffff)
+ if (REG(PCIR_VENDOR, 2) == PCIV_INVALID)
continue;
pcifunchigh = 0;
hdrtype = REG(PCIR_HDRTYPE, 1);
@@ -4191,7 +4196,7 @@ pci_rescan_method(device_t dev)
if (hdrtype & PCIM_MFDEV)
pcifunchigh = PCIB_MAXFUNCS(pcib);
for (f = 0; f <= pcifunchigh; f++) {
- if (REG(PCIR_VENDOR, 2) == 0xffff)
+ if (REG(PCIR_VENDOR, 2) == PCIV_INVALID)
continue;
/*