[U-Boot] [PATCH] at91: board specific lowlevel_init.S

[Ilko Iliev]

Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 15:07 Wed 22 Oct     , Ilko Iliev wrote:
>   
>> Jean-Christophe PLAGNIOL-VILLARD wrote:
>>     
>>> On 13:12 Wed 22 Oct     , Ilko Iliev wrote:
>>>   
>>>       
>>>> Dear Mr. Denk,
>>>>
>>>>     
>>>>         
>>>>> Dear Ilko Iliev,
>>>>>
>>>>> In message <48FDFCA0.4090608 at ronetix.at> you wrote:
>>>>>         
>>>>>           
>>>>>>> Maybe instead of adding mor #ifdef'ery here, we can turn
>>>>>>> lowlevel_init() into a "weak" function that can be redefined by board
>>>>>>> specific code?
>>>>>>>                 
>>>>>>>               
>>>>>> The lowlevel_init() is an assembler function called from another  
>>>>>> assembler function and the attribute .weak doesn't work.
>>>>>>             
>>>>>>             
>>>>> What do you mean by "attribute .weak doesn't work" ?
>>>>>
>>>>>         
>>>>>           
>>>>>> There are no assembler file in the U-BOOT tree which use weak functions.
>>>>>> Do you know how can I make an assembler function weak?
>>>>>>             
>>>>>>             
>>>>> Well, if you don't know, then don't ask me, ask your compiler - he
>>>>> knows how to do this.
>>>>>
>>>>> For example, common/cmd_boot.c has this code snippet right at the
>>>>> beginning:
>>>>>
>>>>>  30
>>>>>  31 /* Allow ports to override the default behavior */
>>>>>  32 __attribute__((weak))
>>>>>  33 unsigned long do_go_exec (ulong (*entry)(int, char *[]), int argc, char *argv[])
>>>>>  34 {
>>>>>  35         return entry (argc, argv);
>>>>>  36 }
>>>>>
>>>>> Compile this with -S option, and you get this:
>>>>>
>>>>>  12 .Ltext0:
>>>>>  13         .align 2
>>>>>  14         .weak   do_go_exec
>>>>>  15         .type   do_go_exec, @function
>>>>>  16 do_go_exec:
>>>>>  17 .LFB87:
>>>>>  18         .file 1 "cmd_boot.c"
>>>>>  19         .loc 1 34 0
>>>>>  20 .LVL0:
>>>>>  21         mflr 0
>>>>>  22 .LCFI0:
>>>>>  23         stwu 1,-16(1)
>>>>> ...
>>>>>
>>>>>
>>>>> So to me it seems as if the attribute .weak is supposed to work just fine.
>>>>>
>>>>> What exactly is not working for you?
>>>>>
>>>>>         
>>>>>           
>>>> With ".weak lowlevel_init" the function is marked as weak (I can see  
>>>> this in the ELF file) but it is not overwritten from the another  
>>>> lowlevel_init().
>>>>     
>>>>         
>>> try
>>>       
>
>   
>>>   
>>>       
>> I tried and the result is:
>> lowlevel_init.S:32: Error: junk at end of line, first unrecognized  
>> character is `='
>>
>>     
> 	sorry try this
>
> 	.global __default_lowlevel_init
> 		.....
> 	.weak	lowlevel_init
> 	.set	lowlevel_init,__default_lowlevel_init
>
> 	after in the other asm
> 	.global lowlevel_init
> 		.......
>
> Best Regards,
> J.
>   
Still doesn't work - the lowlevel_init is weak, but not overwritten.

It works only if the second (strong) function is in the same archive.
Maybe this is a bug of the linker.


-- 
Mit freundlichen Grüßen/With best regards,
Ilko Iliev
Ronetix Development Tools GmbH
CPU Modules, JTAG/BDM Emulators and Flash Programmers
Waidhausenstrasse 13/5, 1140 Vienna, Austria
E-Mail: iliev at ronetix.at; Web: www.ronetix.at