[Sunhelp] Help booting 64bit kernel on an Ultra

[James Lockwood]

On Sun, 5 Sep 1999, Bill Bradford wrote:

> According to the boot() mapage, I have to set the boot-file OBP environment
> variable to a specific file in order to boot 64-bit.  Any suggstions as
> sto what that might be?

Maintenance Commands                                     boot(1M)

[...]

  64-bit SPARC
  Booting UltraSPARC Systems
     Certain platforms may need a firmware  upgrade  to  run  the
     64-bit  kernel.   See  the  Sun  Hardware Platform Guide for
     details. If the 64-bit kernel  packages  are  installed  and
     boot  detects that the platform needs a  firmware upgrade to
     run 64-bit, boot  displays a  message  on  the  console  and
     chooses the 32-bit kernel as the default file instead.

     On systems containing 200MHz or lower  UltraSPARC-1  proces-
     sors,  it  is  possible  for  a user to run a 64-bit program
     designed to exploit a problem that could cause  a  processor
     to  stall.  Since  64-bit  progams  cannot run on the 32-bit
     kernel, the 32-bit kernel is chosen as the default  file  on
     these  systems.

     The code sequence that exploits the problem is very  unusual
     and  is  not likely to be generated by a compiler. Assembler
     code had to be specifically written to demonstrate the prob-
     lem.  It  is  highly  unlikely that a legitimate handwritten
     assembler routine would use this code sequence.

      Users willing to assume the risk that a user might acciden-
     tally  or  deliberately  run  a program that was designed to
     cause a processor to stall may choose to run the 64-bit ker-
     nel    by    modifying   the   boot    policy   file.   Edit
     /platform/platform-name/boot.conf so  that  it  contains  an
     uncommented     line     with     the     variable     named
     ALLOW_64BIT_KERNEL_ON_UltraSPARC_1_CPU set to the value true
     as shown in the example that follows:

     ALLOW_64BIT_KERNEL_ON_UltraSPARC_1_CPU=true

     For more information, see the Sun Hardware Platform Guide.

Basically, remove the comment in the line in /platform/sun4u/boot.conf.

-James