[Bug 370003] Re: "reserve" kernel boot parameter does not work correctly in x86_64

Stefan Bader stefan.bader at canonical.com
Fri Jul 3 12:29:04 UTC 2009

** Also affects: linux (Ubuntu Jaunty)
   Importance: Undecided
       Status: New

** Description changed:

+ SRU Justificatoin:
+ IMPACT: kernel parameter "reserve=" is not handled well on AMD64 and the
+ value in /proc/iomem is not padded by 0xf in the front. The bug
+ LP#187671 depends on this bug.
+ FIX: A patch from Zhang Rui fixed. The patch is also summitted to the
+ mainline. The status on mainline bugzilla is "RESOLVED CODE_FIX". It may
+ be merged into the mainline some day.
+ TEST: I tested on Karmic, Jaunty and Intrepid. The value in /proc/iomem
+ is correct after applying this patch. The original reporter also tested
+ on 2.6.28-11 kernel and reported to work well.
+ ---
  I'm running up-to-date Jaunty, kernel 2.6.28-11.42, x86_64.
  In order to circumvent bug #187671 (which is caused by a bad BIOS
  configuration of the MMIO regions for certain laptops) I added the
  kernel option "reserve=0xffb00000,0x100000" to my default kernel in
  /boot/grub/menu.lst, which has been reported to work on 32-bit systems
  (and which I have been able to verify using a 32-bit liveCD).
  However, the kernel boot parameter does not work correctly on the 64-bit
  kernel. The option I specified is interpreted so that the following line
  appears at the end of /proc/iomem:
  ffffffffffb00000-ffffffffffbfffff : reserved
  which is clearly incorrect: it looks like the 32-bit address is being
  padded with ones instead of zeros. Specifying
  "reserve=0x00000000ffb00000,0x100000" (full-blown 64-bit address) does
  not change anything, the same line appears in /proc/iomem.

** Changed in: linux (Ubuntu Jaunty)
   Importance: Undecided => Medium

** Changed in: linux (Ubuntu Jaunty)
       Status: New => Fix Committed

"reserve" kernel boot parameter does not work correctly in x86_64
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to Linux.

More information about the kernel-bugs mailing list