Loading RTEMS-application with U-boot on Raspberry Pi or MicroZed

[Chris Johns]

On 13/04/2016 06:55, Jan Sommer wrote:
> Am Tuesday 12 April 2016, 08:07:35 schrieb Sebastian Huber:
>> On 11/04/16 15:43, Jan Sommer wrote:
>>> I just tried the same setup with the Xilinx MicroZed board at work.
>>> There, the same behaviour appears.
>>> If I compile a simple bare metal application I can load the binary to
>>> the correct address and run it or load the elf-file somewhere into the
>>> memory and use the bootelf-command to start the application.
>>> If I try to do the same with a compiled RTEMS-application, it won't
>>> work. The same RTEMS-application runs if I put it directly into the
>>> bootimage (without using u-boot).
>>>
>>> How does it work on other ARM-boards? The BeagleBone uses u-boot to
>>> load all its binaries, doesn't it?
>>
>> You have to specify the correct entry and load addresses for the
>> mkimage.  For example:
>>
>
> Ok. If I try to follow that procedure, I have:
> readelf -l  blinker-rtems.exe
> Elf file type is EXEC (Executable file)
> Entry point 0x8040
> There are 4 program headers, starting at offset 52
>
> Program Headers:
>    Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
>    EXIDX          0x010014 0x00100c54 0x00100c54 0x00008 0x00008 R   0x4
>    LOAD           0x0000b4 0x00000000 0x00000000 0x00000 0x01440 RW  0x1
>    LOAD           0x0000b4 0x00008000 0x00008000 0x0f300 0xf8000 RWE 0x4
>    LOAD           0x00f3c0 0x00100000 0x00100000 0x01280 0x7efc000 RW  0x20

The significant sizes are 0x0f300 + 0x01280 which is about 66K.

>
>   Section to Segment mapping:
>    Segment Sections...
>     00     .ARM.exidx
>     01     .vector
>     02     .start .text .init .fini .robarrier
>     03     .rodata .ARM.exidx .eh_frame .init_array .fini_array .jcr .rtemsroset .data .bss .work
>
> .start is in section 02, hence my load address would be 0x8000 and the entry point is 0x8040 (I hope I got that right?).
> If I create my image using:
> mkimage -A arm -O rtems -T standalone -C none -a 0x8000 -e 0x8040 -d blinker-rtems.exe  blinker-rtems.img
> And load it via u-boot with
> fatload mmc 0:1 ${kernel_addr_r} blinker-rtems.img
> bootm ${kernel_addr_r}
>
> It either hangs after Transferring control to RTEMS or resets with:
> ## Booting kernel from Legacy Image at 01000000 ...

Why 01000000? when the lowest address above is 0x00008000?

>
>     Image Name:   blinker1
>
>     Image Type:   ARM RTEMS Standalone Program (uncompressed)
>
>     Data Size:    3494208 Bytes = 3.3 MiB

What is the 3.3M being loaded?

>
>     Load Address: 00008000
>
>     Entry Point:  00008040
>
>     Verifying Checksum ... OK
>
>     Loading Standalone Program ... OK
>
> ## Transferring control to RTEMS (at address 00008040) ...
>
> data abort
>
> pc : [<19273304>]\0x09   lr : [<1bf59eb0>]
>
> reloc pc : [<fd330304>]\0x09   lr : [<00016eb0>]

What is at 00016eb0?

Chris

>
> sp : 1bb46c00  ip : 00000520\0x09 fp : 1bf59e84
>
> r10: 00000000  r9 : 1bb46ee8\0x09 r8 : 400001d3
>
> r7 : 1bb475bc  r6 : 1bf59e84\0x09 r5 : 1bf912bc  r4 : 00000000
>
> r3 : 00000002  r2 : 00000000\0x09 r1 : 00000000  r0 : 400001d3
>
> Flags: nZcv  IRQs off  FIQs off  Mode SVC_32
>
> Resetting CPU ...
>
> resetting ...
>
> Again, if I follow the same procedure with the simple bare metal application, it works.
>
> Best regards,
>
>     Jan
>
>> readelf -l ticker.exe
>>
>> Elf file type is EXEC (Executable file)
>> Entry point 0x400145
>> There are 5 program headers, starting at offset 52
>>
>> Program Headers:
>>     Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
>>     EXIDX          0x00ec70 0x0040eb70 0x0040eb70 0x00008 0x00008 R 0x4
>>     LOAD           0x000100 0x00400000 0x00400000 0x0ebc4 0x0ebc4 RWE 0x40
>>     LOAD           0x00ecc8 0x20401148 0x0040ebc4 0x006a4 0x006a4 RW 0x8
>>     LOAD           0x00f380 0x20400000 0x20400000 0x00000 0x5f000 RW 0x20
>>     LOAD           0x00f36c 0x2045f000 0x2045f000 0x00000 0x01000 RW 0x1
>>
>>    Section to Segment mapping:
>>     Segment Sections...
>>      00     .ARM.exidx
>>      01     .start .text .init .fini .rodata .ARM.exidx .eh_frame
>> .init_array .fini_array .jcr .rtemsroset
>>      02     .data
>>      03     .vector .bss .work
>>      04     .xbarrier .robarrier .rwbarrier .stack .nocachenoload
>>
>> Then use:
>>
>> mkimage -a 0x00400000 -e 0x400145
>>
>>
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