Hi, 在 2023/5/9 23:15, Mark Wielaard 写道: > Hi, > > On Tue, 2023-04-11 at 16:12 +0800, Ying Huang wrote: >> From: Ying Huang <ying.hu...@oss.cipunited.com> >> >> In mips64 little-endian, r_info consists of four byte fields(contains >> three reloc types) and a 32-bit symbol index. In order to adapt >> GELF_R_SYM and GELF_R_TYPE, need convert raw data to get correct symbol >> index and type. > Is there a spec that describes this?
references: https://www.linux-mips.org/pub/linux/mips/doc/ABI/elf64-2.4.pdf Page40 && Page41 > > I see you adjusted elf.h to include: > > +#define ELF64_MIPS_R_TYPE(i) ((i) & 0xff) > +#define ELF64_MIPS_R_TYPE2(i) (((i) >> 8) & 0xff) > +#define ELF64_MIPS_R_TYPE3(i) (((i) >> 16) & 0xff) > > And various new relocation types for MIPS variants. > Our elf.h comes from the glibc project. Have you also submitted these > changes to libc-al...@sourceware.org ? Has submitted. https://sourceware.org/pipermail/libc-alpha/2023-May/148026.html https://sourceware.org/pipermail/libc-alpha/2023-May/148112.html > >> libelf/elf_getdata.c: Some eu-utils use read-mmap method to map file, >> so we need to malloc and memcpy raw data to avoid segment fault. After >> modification, the correct value are saved in the malloced memory not in >> process address space. > Where do these segfaults show up? > >> libelf/elf_updata.c: Because we converted the relocation info in mips >> order when we call elf_getdata.c, so we need to convert the modified data >> in original order bits before writing the data to the file. Has tested on big/little endian machine with big/little endian ELF file, all were OK. > It feels like this is in the wrong place and doesn't take into account > whether the program itself is running on a big or little endian > machine. > > Maybe I am misunderstanding why this conversion is needed always. But I > would have expected a specific conversion function for MIPS for > ELF_T_REL and/or ELF_T_RELA (which are currently generic). > > Cheers, > > Mark 1.Considering that some people directly use the original data instead of the interface function gelf_getrela; 2.Because there is only one parameter, so can not modify the macro ELF64_R_TYPE； 3.If the mips interface function is added, other packages using libelf will not be compatible with mips, and the place where gelf_getrela is used need be modified. Where do you think is the most suitable place to do mips conversion? Thanks, Ying
