[OpenBIOS] Sparc64 memory allocation problem

Mark Cave-Ayland mark.cave-ayland at siriusit.co.uk
Tue Aug 24 23:19:40 CEST 2010

Blue Swirl wrote:

> The problem was that ELF loader didn't allocate the areas. Now with
> r858 OpenBSD gets into kernel:
> Loading FCode image...
> Loaded 4893 bytes
> entry point is 0x4000
> OpenBSD IEEE 1275 Bootblock 1.1
> ..
> Jumping to entry point 0000000000800000 for type 0000000000000001...
> switching to new context: entry point 0x800000 stack 0x00000000ffe02b59
>>> OpenBSD BOOT 1.2
> Trying bsd...
> Booting cdrom:f/bsd
> 2590536 at 0x1000000+3236576@0x1800000+957728 at 0x1b162e0
> symbols @ 0x200241c0 36 start=0x1000000
> CHAINprom_get_msgbuf: test failed
> prom_get_msgbuf: allocated new buf at ffffffff
> prom_get_msgbuf: claiming new buf at ffffffff
> Unhandled Exception 0x0000000000000032
> PC = 0x0000000001080bc4 NPC = 0x0000000001080bc8
> Stopping execution
> I noticed that MilaX had problems with allocation happening, so I made
> the loader ignore the failures. That is probably not correct.

Re-reading the IEEE-1275 spec again, I'm thinking that what we have at 
the moment is wrong. To quote from the definition of the "load" command:

If the “load” method succeeds, and the beginning of the loaded image is 
a valid client program header for the system, allocate memory at the 
address and of the size specified in that header, move the loaded image 
to the address, and perform the function of init-program to initialize 
saved-program-state so that a subsequent go command will begin execution
of that program.

This sounds to me as if "load" as opposed to "init-program" should do 
the relocation if pointed at an ELF file (allocating memory as 
necessary), otherwise as in the case of the Solaris Fcode loader and the 
BSD source given above then all memory setup is managed by the loader 
itself. Hence the invocation of "init-program" is practically a no-op 
since the memory allocations should be already handled.

If you quickly rearrange elf_load.c in this way, does that solve the 
boot problem for both openBSD and Milax?



Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
t: +44 870 608 0063

Sirius Labs: http://www.siriusit.co.uk/labs

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