/proc/iomem and /proc/ioports show 0 for address range

[Hinko Kocevar <hinko.kocevar@xxxxxx>]

[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?

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?

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
00000000-00000000 : ACPI Non-volatile Storage
00000000-00000000 : Reserved
00000000-00000000 : System RAM
00000000-00000000 : Reserved
00000000-00000000 : System RAM
00000000-00000000 : ACPI Non-volatile Storage
00000000-00000000 : Reserved
00000000-00000000 : System RAM
00000000-00000000 : Reserved
  00000000-00000000 : Graphics Stolen Memory
00000000-00000000 : PCI Bus 0000:00
  00000000-00000000 : PCI Bus 0000:01
    00000000-00000000 : PCI Bus 0000:02
      00000000-00000000 : PCI Bus 0000:03
        00000000-00000000 : PCI Bus 0000:04
          00000000-00000000 : PCI Bus 0000:05
          00000000-00000000 : PCI Bus 0000:06
          00000000-00000000 : PCI Bus 0000:07
          00000000-00000000 : PCI Bus 0000:08
          00000000-00000000 : PCI Bus 0000:09
  00000000-00000000 : 0000:00:02.0
  00000000-00000000 : 0000:00:02.0
  00000000-00000000 : PCI Bus 0000:01
    00000000-00000000 : PCI Bus 0000:02
      00000000-00000000 : PCI Bus 0000:03
        00000000-00000000 : PCI Bus 0000:04
          00000000-00000000 : PCI Bus 0000:08
          00000000-00000000 : 0000:08:00.0
          00000000-00000000 : xdma
          00000000-00000000 : 0000:08:00.0
          00000000-00000000 : xdma
        00000000-00000000 : 0000:03:00.0
    00000000-00000000 : 0000:01:00.0
  00000000-00000000 : PCI Bus 0000:12
    00000000-00000000 : 0000:12:00.0
      00000000-00000000 : igb
    00000000-00000000 : 0000:12:00.0
      00000000-00000000 : igb
  00000000-00000000 : PCI Bus 0000:11
    00000000-00000000 : 0000:11:00.0
      00000000-00000000 : igb
    00000000-00000000 : 0000:11:00.0
      00000000-00000000 : igb
  00000000-00000000 : PCI Bus 0000:10
    00000000-00000000 : 0000:10:00.0
      00000000-00000000 : igb
    00000000-00000000 : 0000:10:00.0
      00000000-00000000 : igb
  00000000-00000000 : PCI Bus 0000:0f
    00000000-00000000 : 0000:0f:00.0
      00000000-00000000 : igb
    00000000-00000000 : 0000:0f:00.0
      00000000-00000000 : igb
  00000000-00000000 : 0000:00:1f.3
    00000000-00000000 : ICH HD audio
  00000000-00000000 : 0000:00:14.0
    00000000-00000000 : xhci-hcd
  00000000-00000000 : 0000:00:1f.3
    00000000-00000000 : ICH HD audio
  00000000-00000000 : 0000:00:1f.2
  00000000-00000000 : 0000:00:17.0
    00000000-00000000 : ahci
  00000000-00000000 : 0000:00:1f.4
  00000000-00000000 : 0000:00:17.0
    00000000-00000000 : ahci
  00000000-00000000 : 0000:00:17.0
    00000000-00000000 : ahci
  00000000-00000000 : 0000:00:16.0
    00000000-00000000 : mei_me
  00000000-00000000 : 0000:00:15.1
    00000000-00000000 : lpss_dev
      00000000-00000000 : i2c_designware.1 lpss_dev
    00000000-00000000 : lpss_priv
    00000000-00000000 : idma64.1
      00000000-00000000 : idma64.1 idma64.1
  00000000-00000000 : 0000:00:15.0
    00000000-00000000 : lpss_dev
      00000000-00000000 : i2c_designware.0 lpss_dev
    00000000-00000000 : lpss_priv
    00000000-00000000 : idma64.0
      00000000-00000000 : idma64.0 idma64.0
  00000000-00000000 : 0000:00:14.2
    00000000-00000000 : Intel PCH thermal driver
  00000000-00000000 : 0000:00:08.0
  00000000-00000000 : pnp 00:04
00000000-00000000 : PCI MMCONFIG 0000 [bus 00-ff]
  00000000-00000000 : Reserved
    00000000-00000000 : pnp 00:04
00000000-00000000 : PCI Bus 0000:00
  00000000-00000000 : pnp 00:05
  00000000-00000000 : INT345D:00
    00000000-00000000 : INT345D:00 INT345D:00
  00000000-00000000 : pnp 00:05
  00000000-00000000 : INT345D:00
    00000000-00000000 : INT345D:00 INT345D:00
  00000000-00000000 : INT345D:00
    00000000-00000000 : INT345D:00 INT345D:00
  00000000-00000000 : pnp 00:05
    00000000-00000000 : iTCO_wdt
  00000000-00000000 : Reserved
  00000000-00000000 : pnp 00:05
  00000000-00000000 : pnp 00:05
  00000000-00000000 : pnp 00:05
00000000-00000000 : Reserved
  00000000-00000000 : IOAPIC 0
00000000-00000000 : Reserved
  00000000-00000000 : HPET 0
    00000000-00000000 : PNP0103:00
00000000-00000000 : pnp 00:04
00000000-00000000 : pnp 00:04
00000000-00000000 : pnp 00:04
00000000-00000000 : pnp 00:04
00000000-00000000 : MSFT0101:00
  00000000-00000000 : MSFT0101:00
00000000-00000000 : pnp 00:04
00000000-00000000 : dmar0
00000000-00000000 : dmar1
00000000-00000000 : Local APIC
  00000000-00000000 : Reserved
00000000-00000000 : Reserved
  00000000-00000000 : INT0800:00
    00000000-00000000 : pnp 00:04
00000000-00000000 : System RAM
00000000-00000000 : RAM buffer
[dev@bd-cpu18 ~]$ cat /proc/ioports
0000-0000 : PCI Bus 0000:00
  0000-0000 : dma1
  0000-0000 : pic1
  0000-0000 : timer0
  0000-0000 : timer1
  0000-0000 : keyboard
  0000-0000 : keyboard
  0000-0000 : rtc0
  0000-0000 : dma page reg
  0000-0000 : pic2
  0000-0000 : dma2
  0000-0000 : fpu
    0000-0000 : PNP0C04:00
  0000-0000 : vga+
  0000-0000 : serial
  0000-0000 : serial
  0000-0000 : iTCO_wdt
  0000-0000 : pnp 00:00
  0000-0000 : pnp 00:01
0000-0000 : PCI conf1
0000-0000 : PCI Bus 0000:00
  0000-0000 : pnp 00:00
  0000-0000 : pnp 00:00
    0000-0000 : ACPI PM1a_EVT_BLK
    0000-0000 : ACPI PM1a_CNT_BLK
    0000-0000 : ACPI PM_TMR
    0000-0000 : ACPI PM2_CNT_BLK
    0000-0000 : pnp 00:03
    0000-0000 : ACPI GPE0_BLK
  0000-0000 : PCI Bus 0000:01
    0000-0000 : PCI Bus 0000:02
      0000-0000 : PCI Bus 0000:03
        0000-0000 : PCI Bus 0000:04
          0000-0000 : PCI Bus 0000:05
          0000-0000 : PCI Bus 0000:06
          0000-0000 : PCI Bus 0000:07
          0000-0000 : PCI Bus 0000:08
          0000-0000 : PCI Bus 0000:09
  0000-0000 : PCI Bus 0000:12
    0000-0000 : 0000:12:00.0
  0000-0000 : PCI Bus 0000:11
    0000-0000 : 0000:11:00.0
  0000-0000 : PCI Bus 0000:10
    0000-0000 : 0000:10:00.0
  0000-0000 : PCI Bus 0000:0f
    0000-0000 : 0000:0f:00.0
  0000-0000 : 0000:00:02.0
  0000-0000 : 0000:00:1f.4
    0000-0000 : i801_smbus
  0000-0000 : 0000:00:17.0
    0000-0000 : ahci
  0000-0000 : 0000:00:17.0
    0000-0000 : ahci
  0000-0000 : 0000:00:17.0
    0000-0000 : ahci
  0000-0000 : pnp 00:06
  0000-0000 : pnp 00:00
    0000-0000 : pnp 00:00
      0000-0000 : pnp 00:00


Thanks!

//hinko