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Re: [rfc / remote protocol] ELF segment based qOffsets

Hello all,

We've ran into the following problem while running the ppc cross-gdb
with the U-Boot firmware image:

bash# ./gdb u-boot
GNU gdb Red Hat Linux (6.7-1rh)
Copyright (C) 2007 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "--host=i686-pc-linux-gnu --target=ppc-linux".
The target architecture is set automatically (currently powerpc:403)

warning: Loadable segment ".resetvec" outside of ELF segments

warning: Loadable segment ".bootpg" outside of ELF segments

bash# readelf -lS u-boot There are 27 section headers, starting at offset 0xc3dc0:

Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .resetvec PROGBITS fffffffc 02e208 000004 00 AX 0 0 1
[ 2] .bootpg PROGBITS fffff000 02d20c 00033c 00 AX 0 0 1
[ 3] .text PROGBITS fffc0000 0000a0 022f9c 00 AX 0 0 16
[ 4] .rodata PROGBITS fffe2f9c 02303c 007250 00 A 0 0 4
[ 5] .reloc PROGBITS fffea200 02a2a0 001204 00 WA 0 0 1
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x0000a0 0xfffc0000 0xfffc0000 0x2d16c 0x35cd0 RWE 0x10
LOAD 0x02d20c 0xfffff000 0xfffff000 0x01000 0x01000 R E 0x1
GNU_STACK 0x000000 0x00000000 0x00000000 0x00000 0x00000 RWE 0x4

Section to Segment mapping:
Segment Sections...
00 .text .rodata .reloc .data .data.rel.local .data.rel data .u_boot_cmd
01 .resetvec .bootpg

You see, the warnings are caused by the fact that the segment 01 has address/size values which wraps to 0 in the following 'if' condition introduced by the $subj in elfread.c, elf_symfile_segments(): ... && vma < segments[j]->p_vaddr + segments[j]->p_memsz)

The place above is trivial to fix, but I wonder will be any other consequences to the remote debugging of such kind of images? (I can't try this at the moment)


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