Re: git: 68cbe189fdd3 - main - pci: Don't try to read cfg registers of non-existing devices
Date: Thu, 25 Nov 2021 09:54:23 UTC
On Thu, Nov 25, 2021 at 1:55 AM Wojciech Macek <wma@freebsd.org> wrote: > The branch main has been updated by wma: > > URL: > https://cgit.FreeBSD.org/src/commit/?id=68cbe189fdd3c572476f8af9219a5d335f05b51a > > commit 68cbe189fdd3c572476f8af9219a5d335f05b51a > Author: Kornel Duleba <mindal@semihalf.com> > AuthorDate: 2021-11-23 08:13:56 +0000 > Commit: Wojciech Macek <wma@FreeBSD.org> > CommitDate: 2021-11-25 08:53:40 +0000 > > 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. > We didn't use to bail out if function 0 was not present due to odd balls (I think on sparc64) which have long ago since become irrelevant, so this should be OK. Warner > Sponsored by: Alstom > Obtained from: Semihalf > Reviewed by: jhb > MFC after: 2 weeks > Differential revision: https://reviews.freebsd.org/D33059 > --- > sys/dev/pci/pci.c | 15 ++++++++++----- > 1 file 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; > > /* >