[U-Boot] sparc leon3 linking problem

[Daniel Hellstrom]

On 03/12/2014 01:52 PM, Tom Rini wrote:
> On Tue, Mar 11, 2014 at 03:14:26PM -0700, Kameron Larsen wrote:
>
>> Hello,
>>
>> I'm bringing up a board based on the board/gaisler/gr_xc3s_1500/ design. To
>> keep things simple, we can use this design exactly as is.
>>
>> My problem starts in the relocation section of arch/sparc/cpu/leon3/start.S
>> which I'll paste here for convenience:
>>
>> /* un relocated start address of monitor */
>> #define TEXT_START _text
>>
>> /* un relocated end address of monitor */
>> #define DATA_END __init_end
>>
>> reloc:
>>      set TEXT_START,%g2
>>      set DATA_END,%g3
>>      set CONFIG_SYS_RELOC_MONITOR_BASE,%g4
>> reloc_loop:
>>      ldd [%g2],%l0
>>      ldd [%g2+8],%l2
>>      std %l0,[%g4]
>>      std %l2,[%g4+8]
>>      inc 16,%g2
>>      subcc   %g3,%g2,%g0
>>      bne reloc_loop
>>      inc 16,%g4
>>
>> As can be seen, this relies upon the location of the _text and __init_end
>> symbols. These symbols are only known to the linker and should be filled in
>> by the linker to point to the actual addresses within the compiled program.
>>   I can see these addresses by running an objdump -x on the final u-boot
>> binary. The relevant portions are below:
>>
>> SYMBOL TABLE:
>> 00000000 g       .text  00000000 _text
>> 00036000 g       *ABS*  00000000 __init_end
>>
>> So 0x00000000, and 0x00036000 are the values I expect to be used for _text
>> and __init_end respectively. However, looking at the disassembled u-boot
>> binary (objdump -d), I see that they are not. Instead they are giving the
>> values of 0xd50 and 0xd44:
>>
>> sparc-elf-objdump -d u-boot:
>> 000010a4 <reloc>:
>>      10a4:       05 00 00 03     sethi  %hi(0xc00), %g2
>>      10a8:       84 10 a1 50     or  %g2, 0x150, %g2     ! d50
>> <MINFRAME+0xcf4>
>>      10ac:       07 00 00 03     sethi  %hi(0xc00), %g3
>>      10b0:       86 10 e1 44     or  %g3, 0x144, %g3     ! d44
>> <MINFRAME+0xce8>
>>      10b4:       09 10 fe 38     sethi  %hi(0x43f8e000), %g4
>>
>> 000010b8 <reloc_loop>:
>>      10b8:       e0 18 80 00     ldd  [ %g2 ], %l0
>>      10bc:       e4 18 a0 08     ldd  [ %g2 + 8 ], %l2
>>      10c0:       e0 39 00 00     std  %l0, [ %g4 ]
>>      10c4:       e4 39 20 08     std  %l2, [ %g4 + 8 ]
>>      10c8:       84 00 a0 10     add  %g2, 0x10, %g2
>>      10cc:       80 a0 c0 02     cmp  %g3, %g2
>>      10d0:       12 bf ff fa     bne  10b8 <reloc_loop>
>>      10d4:       88 01 20 10     add  %g4, 0x10, %g4
>>
>> FWIW, MINFRAME is the last declared variable in start.S before this reloc
>> label.
>>
>> I've tried this with both the 3.4.4 and the 4.4.2 toolchains distributed by
>> Gaisler. Both behave the same way.
>>
>> Why isn't ld filling in the correct values of linker symbols?
> Any ideas Daniel?  Thanks!
>
Hi! I've looked at it quickly but couldn't see any obvious problems.

Daniel