dear wolfgang,
On Fri, 25 Mar 2011, Wolfgang Denk wrote:
> > Add ENTRY() command to the linker script so that entry point is
> > correctly marked in the final ELF file.
>
> Which exact problem are you trying to fix?
i'm sorry, i probably should have been more verbose in the
changelog.
when cross-compiling u-boot for the avnet virtex-4 minimodule
(make fx12mm_config; make, with SYS_TEXT_BASE=0x02000000) i end
up with a u-boot.lds linker script that has no ENTRY() command.
this will result in an incorrect ELF file: the entry point in
the ELF header points to the first byte of the first loadable
segment (which is ~the version string at 0x02000004: "U-Boot
2011..") instead of the first instruction to be executed at
_start (at 0x02002100 in this case).
powerpc-405-linux-gnu-readelf -e u-boot:
ELF Header:
Magic: 7f 45 4c 46 01 02 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, big endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: PowerPC
Version: 0x1
Entry point address: 0x2000000
..
powerpc-405-linux-gnu-objdump -d u-boot:
Disassembly of section .text:
02000000 <version_string-0x4>:
2000000: 27 05 19 56 dozi r24,r5,6486
02000004 <version_string>:
2000004: 55 2d 42 6f rlwinm. r13,r9,8,9,23
2000008: 6f 74 20 32 xoris r20,r27,8242
200000c: 30 31 31 2e addic r1,r17,12590
2000010: 30 33 2d 72 addic r1,r19,11634
...
02002100 <_start>:
2002100: 38 80 00 00 li r4,0
2002104: 7c 99 eb a6 mtpmc1 r4
2002108: 7c 9a eb a6 mtdcwr r4
200210c: 7c 94 f3 a6 mtesr r4
2002110: 7c 9a f3 a6 mttcr r4
...
anything trying to load and run this ELF file (eg xilinx's XMD
debugger, or a bootloader stored in the FPGA fabric) will fail
to do so because the processor will jump to 0x02000000 and try
to execute the version string.
best regards,
--
mazsi
----------------------------------------------------------------
strawberry fields forever! ma...@imrek.org
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