lkml.org 
[lkml]   [2020]   [Sep]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[RFC PATCH v3 3/4] objtool: correct rebuilding of reloc sections
    From: Martin Schwidefsky <schwidefsky@de.ibm.com>

    Currently relocations generated in elf_rebuild_rel_reloc_section/
    elf_rebuild_rela_reloc_section functions are broken if the objtool is
    built and run on big endian system. E.g. the following errors pop up
    during x86 cross compilation:
    x86_64-9.1.0-ld: fs/efivarfs/inode.o: bad reloc symbol index (0x2000000 >=
    0x22) for offset 0 in section `.orc_unwind_ip'
    x86_64-9.1.0-ld: final link failed: bad value

    To address that convert those functions to do things similar to
    elf_write_reloc(), reuse gelf_update_rel/gelf_update_rela libelf library
    functions.

    Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
    Co-developed-by: Vasily Gorbik <gor@linux.ibm.com>
    Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
    ---
    tools/objtool/elf.c | 34 +++++++++++++++++++---------------
    1 file changed, 19 insertions(+), 15 deletions(-)

    diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
    index 4e1d7460574b..5c0341b0cde3 100644
    --- a/tools/objtool/elf.c
    +++ b/tools/objtool/elf.c
    @@ -829,25 +829,27 @@ static int elf_rebuild_rel_reloc_section(struct section *sec, int nr)
    {
    struct reloc *reloc;
    int idx = 0, size;
    - GElf_Rel *relocs;
    + void *buf;

    /* Allocate a buffer for relocations */
    - size = nr * sizeof(*relocs);
    - relocs = malloc(size);
    - if (!relocs) {
    + size = nr * sizeof(GElf_Rel);
    + buf = malloc(size);
    + if (!buf) {
    perror("malloc");
    return -1;
    }

    - sec->data->d_buf = relocs;
    + sec->data->d_buf = buf;
    sec->data->d_size = size;
    + sec->data->d_type = ELF_T_REL;

    sec->sh.sh_size = size;

    idx = 0;
    list_for_each_entry(reloc, &sec->reloc_list, list) {
    - relocs[idx].r_offset = reloc->offset;
    - relocs[idx].r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
    + reloc->rel.r_offset = reloc->offset;
    + reloc->rel.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
    + gelf_update_rel(sec->data, idx, &reloc->rel);
    idx++;
    }

    @@ -858,26 +860,28 @@ static int elf_rebuild_rela_reloc_section(struct section *sec, int nr)
    {
    struct reloc *reloc;
    int idx = 0, size;
    - GElf_Rela *relocs;
    + void *buf;

    /* Allocate a buffer for relocations with addends */
    - size = nr * sizeof(*relocs);
    - relocs = malloc(size);
    - if (!relocs) {
    + size = nr * sizeof(GElf_Rela);
    + buf = malloc(size);
    + if (!buf) {
    perror("malloc");
    return -1;
    }

    - sec->data->d_buf = relocs;
    + sec->data->d_buf = buf;
    sec->data->d_size = size;
    + sec->data->d_type = ELF_T_RELA;

    sec->sh.sh_size = size;

    idx = 0;
    list_for_each_entry(reloc, &sec->reloc_list, list) {
    - relocs[idx].r_offset = reloc->offset;
    - relocs[idx].r_addend = reloc->addend;
    - relocs[idx].r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
    + reloc->rela.r_offset = reloc->offset;
    + reloc->rela.r_addend = reloc->addend;
    + reloc->rela.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
    + gelf_update_rela(sec->data, idx, &reloc->rela);
    idx++;
    }

    --
    ⣿⣿⣿⣿⢋⡀⣀⠹⣿⣿⣿⣿
    ⣿⣿⣿⣿⠠⣶⡦⠀⣿⣿⣿⣿
    ⣿⣿⣿⠏⣴⣮⣴⣧⠈⢿⣿⣿
    ⣿⣿⡏⢰⣿⠖⣠⣿⡆⠈⣿⣿
    ⣿⢛⣵⣄⠙⣶⣶⡟⣅⣠⠹⣿
    ⣿⣜⣛⠻⢎⣉⣉⣀⠿⣫⣵⣿
    \
     
     \ /
      Last update: 2020-10-01 00:19    [W:7.352 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site