[Bug 412375] [NEW] Fails to read registers on 32 bit

[jasmineaura]

Public bug reported:

Binary package hint: msr-tools

This is the same exact bug reported in debian:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=495445

On a 32-bit ubuntu system, trying to rdmsr 0xc0010041 or 0xc0010042 gives the following error:
rdmsr:pread: Invalid argument
or sometimes gives a plain old "0"...

Example:
--------------------------------------
root at evrx:/root/drivers/phc# rdmsr 0xc0010042
rdmsr:pread: Invalid argument
root at evrx:/root/drivers/phc# rdmsr 0xc0010041
rdmsr:pread: Invalid argument
root at evrx:/root/drivers/phc# rdmsr c0010042
0
root at evrx:/root/drivers/phc# rdmsr c0010041
0
---------------------------------------

My very basic python script, however, reads the offsets just fine:
---------------------------------------
#!/usr/bin/env python

import os

MSR_FIDVID_CTL=int(0xc0010041)
MSR_FIDVID_STATUS=int(0xc0010042)

msrfile = os.open("/dev/cpu/0/msr", os.O_RDONLY);

os.lseek(msrfile, MSR_FIDVID_STATUS, 0);        ##jump to where current values lie
value = os.read(msrfile, 8)                     ##read 8 bytes

print "--- MSR_FIDVID_STATUS ---"
for v in value:
        print ord(v)

os.lseek(msrfile, MSR_FIDVID_CTL, 0);           ##jump to where target values lie
value = os.read(msrfile, 8)                     ##read 8 bytes

print "--- MSR_FIDVID_CTL ---"
for v in value:
        print ord(v)

os.close(msrfile)
---------------------------------------

Example Output from my python script:
---------------------------------------
root at evrx:/root/drivers/phc# ./test.py
--- MSR_FIDVID_STATUS ---
0
0
8
17
30
30
17
51
--- MSR_FIDVID_CTL ---
0
30
0
0
1
0
0
0
---------------------------------------


msr-tools from the 1.1.2-1 pkg works fine on 64 bit, just not on 32-bit...

However, they work fine (on 32-bit) if compiled from non-debian/non-
ubuntu sources.


Quote, from the previously mentioned debian bug report on same package:
---------------------------------------
The defines are not being set correctly.  Building the debian package it
is compiled like this:
gcc -Wall -g -O2 -g -Wall -O2  -o wrmsr wrmsr.c
gcc -Wall -g -O2 -g -Wall -O2  -o rdmsr rdmsr.c

Building without debian patches it is like this:
gcc -Wall -g -O2 -fomit-frame-pointer -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64  -o wrmsr wrmsr.c
gcc -Wall -g -O2 -fomit-frame-pointer -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64  -o rdmsr rdmsr.c

I see the debian patch adds #define __USE_UNIX98 to the source, but that
doesn't appear to be sufficient.  
---------------------------------------

Hope this helps..

** Affects: msr-tools (Ubuntu)
     Importance: Undecided
         Status: New

** Description changed:

  Binary package hint: msr-tools
  
  This is the same exact bug reported in debian:
  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=495445
  
- On a 32-bit ubuntu system, trying to rdmsr 0xC0010015 or 0xC0011023 gives the following error:
+ On a 32-bit ubuntu system, trying to rdmsr 0xc0010041 or 0xc0010042 gives the following error:
  rdmsr:pread: Invalid argument
  or sometimes gives a plain old "0"...
  
  Example:
  --------------------------------------
  root at evrx:/root/drivers/phc# rdmsr 0xc0010042
  rdmsr:pread: Invalid argument
  root at evrx:/root/drivers/phc# rdmsr 0xc0010041
  rdmsr:pread: Invalid argument
  root at evrx:/root/drivers/phc# rdmsr c0010042
  0
  root at evrx:/root/drivers/phc# rdmsr c0010041
  0
  ---------------------------------------
  
  My very basic python script, however, reads the offsets just fine:
  ---------------------------------------
  #!/usr/bin/env python
  
  import os
  
  MSR_FIDVID_CTL=int(0xc0010041)
  MSR_FIDVID_STATUS=int(0xc0010042)
  
  msrfile = os.open("/dev/cpu/0/msr", os.O_RDONLY);
  
  os.lseek(msrfile, MSR_FIDVID_STATUS, 0);        ##jump to where current values lie
  value = os.read(msrfile, 8)                     ##read 8 bytes
  
  print "--- MSR_FIDVID_STATUS ---"
  for v in value:
          print ord(v)
  
  os.lseek(msrfile, MSR_FIDVID_CTL, 0);           ##jump to where target values lie
  value = os.read(msrfile, 8)                     ##read 8 bytes
  
  print "--- MSR_FIDVID_CTL ---"
  for v in value:
          print ord(v)
  
  os.close(msrfile)
  ---------------------------------------
  
  Example Output from my python script:
  ---------------------------------------
  root at evrx:/root/drivers/phc# ./test.py
  --- MSR_FIDVID_STATUS ---
  0
  0
  8
  17
  30
  30
  17
  51
  --- MSR_FIDVID_CTL ---
  0
  30
  0
  0
  1
  0
  0
  0
  ---------------------------------------
  
  
- msr-tools from the 1.1.2-1 deb pkg works fine on 64 bit, just not on 32-bit...
+ msr-tools from the 1.1.2-1 pkg works fine on 64 bit, just not on 32-bit...
  
  However, they work fine (on 32-bit) if compiled from non-debian/non-
  ubuntu sources.
  
  
  Quote, from the previously mentioned debian bug report on same package:
  ---------------------------------------
  The defines are not being set correctly.  Building the debian package it
  is compiled like this:
  gcc -Wall -g -O2 -g -Wall -O2  -o wrmsr wrmsr.c
  gcc -Wall -g -O2 -g -Wall -O2  -o rdmsr rdmsr.c
  
  Building without debian patches it is like this:
  gcc -Wall -g -O2 -fomit-frame-pointer -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64  -o wrmsr wrmsr.c
  gcc -Wall -g -O2 -fomit-frame-pointer -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64  -o rdmsr rdmsr.c
  
  I see the debian patch adds #define __USE_UNIX98 to the source, but that
  doesn't appear to be sufficient.  
  ---------------------------------------
  
  Hope this helps..

-- 
Fails to read registers on 32 bit
https://bugs.launchpad.net/bugs/412375
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