[U-Boot-Users] MIPS (purple) compilation problems.

[Ronen Shitrit <rshitrit@il.marvell.com>]

Hi

Thanks for your help.

The code I disassemble below is the u-boot image.
Believe me I tried all the flags that you can think about - but non of 
it gave me a "clean" u-boot image.

As I understand the code must be PIC, other wise when we will relocate 
to the DRAM in the next function
call we will jump back to the Flash, cause  the compiler might use 
absolute jump and not a relative branch/jump.
any way I found how to overcome the below problem and now the compiler 
generate the same code as you have,
I use gcc -membedded-pic and  ld --relocatable , but this option doesn't 
work well with my elf compiler(as it is mentioned
in the man), and it cause some other problems.
Can you please send me a short description how did you built your cross 
compiler.

Thanks Ronen


Wolfgang Denk wrote:

>In message <4057256E.3080604@il.marvell.com> you wrote:
>  
>
>>I'm trying to port the U-Boot to Marvell board with MIPS (rm7000)
>>    
>>
>
>In your Subject: you write: MIPS  (purple)  compilation  problems.  I
>cannot see any relation to the Infineon Purple board here??
>
>  
>
>>I see that after relocating to the DRAM the disassembly of the u-boot 
>>shows me
>>that we jump back to the flash:
>>    
>>
>
>What did you disassemble? The code in RAM?
>
>  
>
>>start.S:                                            dis:
>>la     t9,board_init_r                    lui     t9,0xbfc1
>>                                                  addiu     t9,20140
>>j      t9                                        jr     t9
>>    
>>
>
>This cannot work. This is what I see for the "purple" board:
>
>...
>        move    a0, a1
> 564:   00a02021        move    a0,a1
>        la      t9, board_init_r
> 568:   8f990000        lw      t9,0(gp)
>        j       t9
> 56c:   03200008        jr      t9
>        move    a1, a2          /* delay slot                   */
> 570:   00c02821        move    a1,a2
>
>
>  
>
>>I see that I get the same problem when I jump to printf etc.
>>maybe it is because I don't compile the code as PIC? Is there any 
>>    
>>
>
>If you meddle with the compiler options you better know EXACTLY  what
>you are doing.
>
>  
>
>>special compilation flag I should use?
>>    
>>
>
>Use the flags as they are defined in U-Boot. This is what  works  for
>me.
>
>  
>
>>Can someone please send me a disassembly of the U-Boot for any of the 
>>MIPS board (purple, incaip or dbaux100).
>>    
>>
>
>See above.
>
>  
>
>>Is there any special handle for relocating of the MIPS that is different 
>>from the PPC, that I should take under consideration???
>>    
>>
>
>There are differences, but your problem  is  not  caused  by  any  of
>these. You use bad compiler options and/or misconfigured tools.
>
>  
>
>>>     c1: warning: -G is incompatible with PIC code which is the default
>>>      .........
>>>and an LD error:
>>>     mips64-elf-ld: common/main.o: linking PIC files with non-PIC files
>>>      
>>>
>
>I don't understand why you don't follow the clear hints the  compiler
>is giving: "incompatible with PIC code which is the default". If your
>compiler is configured such that PIC is the default, and this default
>is  causing incompatibilities, I would try to find out which compiler
>option can be used NOT to generate PIC. ["-fno-pic" comes to mind.]
>
>
>Wolfgang Denk
>
>  
>

-- 
Ronen Shitrit

M.S.I.L
D.N. Misgav  20184
Tel:   +972-4-9951000
Fax:   +972-4-9951001
Email: mailto: ronen.shitrit at il.marvell.com
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