On 1/13/21 2:29 AM, Hinko Kocevar wrote: > [I noticed this while working on PCI devices; not sure which kernel list would be best for this, though] > > I noticed that my system shows address range for iomem and ioports as all 0. Sometimes (after a power cycle) the addresses are proper, albeit I have not been able to see that in a while now, after performing numerous reboots in the last coupe of days. > > FWIW, I think the list of devices (names, count) looks the same in both cases. The system seems to work in both cases; at least I have not seen any complaints in kernel logs, OTOH, not sure what the error message would be. > > What may be the reason for not getting the proper addresses listed? config STRICT_DEVMEM bool "Filter access to /dev/mem" and config IO_STRICT_DEVMEM bool "Filter I/O access to /dev/mem" so what are your CONFIG_STRICT_DEVMEM and CONFIG_IO_STRICT_DEVMEM set to? What do you see in /proc/iomem and /proc/ioports if you are admin/root? That should be non-zero values. > This likely poses any issues for userspace tools that would look at those /proc files, OTOH, I wonder if would kernel suffer in any way as well? Yes, it could affect userspace. > Kernel version is 5.10.0 (pci git tree). > > [dev@bd-cpu18 ~]$ cat /proc/iomem > 00000000-00000000 : Reserved > 00000000-00000000 : System RAM > 00000000-00000000 : Reserved > 00000000-00000000 : PCI Bus 0000:00 > 00000000-00000000 : Video ROM > 00000000-00000000 : Reserved > 00000000-00000000 : System ROM > 00000000-00000000 : System RAM > 00000000-00000000 : Kernel code > 00000000-00000000 : Kernel rodata > 00000000-00000000 : Kernel data > 00000000-00000000 : Kernel bss -- ~Randy You can't do anything without having to do something else first. -- Belefant's Law
