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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2015-12-14 07:56:02 +0000
committerabiesheuvel <abiesheuvel@Edk2>2015-12-14 07:56:02 +0000
commit088dc2450860a64f58a5c0f2b1623f1c1252c006 (patch)
tree0d39a897479b97d252b4cdd1d2f4e467bebcdd16 /BuildNotes2.txt
parentb12ef6b964f8fc0532432ebffd67748648487133 (diff)
downloadedk2-platforms-088dc2450860a64f58a5c0f2b1623f1c1252c006.tar.xz
BaseTools/GenFw RVCT: fix relocation processing of PT_DYNAMIC sections
Unlike GNU ld, which can be instructed to emit symbol based static relocations into fully linked binaries using the --emit-relocs command line switch, the RVCT armlink tool can only emit dynamic relocations into the PT_DYNAMIC segment. This has two consequences . we can only identify absolute relocations, so there is no way to fix up relative relocations between sections, or check their validity in the PE/COFF layout . the r_offset fields of the PT_DYNAMIC DT_REL entries are relative either to the base of the image or to any of its segments but *not* to the base of the input section that contains the location they refer to, and converting them to PE/COFF image offsets is non-trivial unless the sections are laid out in the same way in the ELF and PE/COFF versions of the binary. There is really only one way to deal with this, and that is to require that the ELF and PE/COFF versions of the binary are identical in memory. So enforce that in the code. Also, fix the utterly broken relocation fixup code that dereferences ELF32_R_SYM(r_info) both as a 1-based program header index and a 0-based section header index. If this code ever produced working binaries, it was purely by chance. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Liming Gao <liming.gao@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19236 6f19259b-4bc3-4df7-8a09-765794883524
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