Unable to run run-time loaded code on ZedBoard

[Chris Johns]

On 20/10/2015 8:59 am, Patrick Gauvin wrote:
> 
> Here is the dissasembly with raw instructions for the rtems main
> symbol (rtl: sym:add:20 name:30:rtems_main           bind:1  type:2
> val:0x2138f9 sect:1 size:88):
> 
> (gdb) disas /r 0x2138f9,0x2138f9+88
> Dump of assembler code from 0x2138f9 to 0x213951:
>    0x002138f9:  b5 84   push    {r7, lr}
>    0x002138fb:  b0 00   sub     sp, #16
>    0x002138fd:  af 78   add     r7, sp, #0
>    0x002138ff:  60 39   str     r0, [r7, #4]
>    0x00213901:  60 43   str     r1, [r7, #0]
>    0x00213903:  f6 60 10 c0     movw    r0, #14688      ; 0x3960
>    0x00213907:  f2 21 00 79     movt    r0, #33 ; 0x21
>    0x0021390b:  68 43   ldr     r1, [r7, #4]
>    0x0021390d:  f6 80 12 c0     movw    r2, #14720      ; 0x3980
>    0x00213911:  f2 21 02 05     movt    r2, #33 ; 0x21
>    0x00213915:  f7 08 fe 00     bl      0x119528 <printf>
>    0x00213919:  23 fb   movs    r3, #0
>    0x0021391b:  60 0f   str     r3, [r7, #12]
>    0x0021391d:  e0 fb   b.n     0x21393e
>    0x0021391f:  68 9b   ldr     r3, [r7, #12]
>    0x00213921:  00 3a   lsls    r3, r3, #2
>    0x00213923:  68 13   ldr     r2, [r7, #0]
>    0x00213925:  44 1b   add     r3, r2
>    0x00213927:  68 43   ldr     r3, [r3, #0]
>    0x00213929:  f6 88 10 c0     movw    r0, #14728      ; 0x3988
>    0x0021392d:  f2 21 00 f9     movt    r0, #33 ; 0x21
>    0x00213931:  68 1a   ldr     r1, [r7, #12]
>    0x00213933:  46 05   mov     r2, r3
>    0x00213935:  f7 f8 fd fb     bl      0x119528 <printf>

Looks fine.

>    0x00213939:  68 01   ldr     r3, [r7, #12]
>    0x0021393b:  33 fb   adds    r3, #1
>    0x0021393d:  60 fa   str     r3, [r7, #12]
>    0x0021393f:  68 7b   ldr     r2, [r7, #12]
>    0x00213941:  68 9a   ldr     r3, [r7, #4]
>    0x00213943:  42 eb   cmp     r2, r3
>    0x00213945:  db 7b   blt.n   0x21391e
>    0x00213947:  68 18   ldr     r3, [r7, #4]
>    0x00213949:  46 10   mov     r0, r3
>    0x0021394b:  37 bd   adds    r7, #16
>    0x0021394d:  46 80   mov     sp, r7
>    0x0021394f:  bd 44   pop     {r7, pc}
> End of assembler dump.
> 
> If you want the full object file before it is loaded, I can dump it
> from memory but I'm not sure GDB will decode the instructions.
> 
>>>> Note, ARM veneers is an outstanding task I need to complete.
>>>
>>> The bl instructions to printf inside the loaded code are within range
>>> (16 MB for the 32bit T32 bl) so I don't think this application
>>> requires veneers. I will keep this in mind for the future, though.
>>
>> Do you have a special option on? I thought the default was 24bit.
> 
> I don't have any special option on, but GCC seems to be generating the
> 32bit T32 encoding of bl rather than the 16bit (unless I'm
> misinterpreting the hex dump, but even so the lesser 4MB range would
> be enough in this case).
> 

Hmm maybe a data cache flush and instruction cache invalidate is needed.

Maybe the L2 cache support being added has broken this test.

Chris