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

[Jean-Christophe PLAGNIOL-VILLARD]

On 16:01 Wed 22 Oct     , Ilko Iliev wrote:
> 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.
> 
Do you specify that the 2 is type "func"

Best Regards,
J.