(+CC: Matthias, who might be interested)
On Fri, Nov 15, 2019 at 2:42 AM Masahiro Yamada
<yamada.masahiro@xxxxxxxxxxxxx> wrote:
>
> When CONFIG_MODULE_REL_CRCS is enabled, the value of __crc_* is not
> an absolute value, but the address to the CRC data embedded in the
> .rodata section.
>
> Getting the data pointed by the symbol value is somewhat complex.
> Split it out into a new helper, sym_get_data().
>
> I will reuse it to refactor namespace_from_kstrtabns() in the next
> commit.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> ---
>
> scripts/mod/modpost.c | 17 +++++++++++++----
> 1 file changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 46d7f695fe7f..cd885573daaf 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -308,6 +308,18 @@ static const char *sec_name(struct elf_info *elf, int secindex)
> return sech_name(elf, &elf->sechdrs[secindex]);
> }
>
> +static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
> +{
> + Elf_Shdr *sechdr = &info->sechdrs[sym->st_shndx];
> + unsigned long offset;
> +
> + offset = sym->st_value;
> + if (info->hdr->e_type != ET_REL)
> + offset -= sechdr->sh_addr;
> +
> + return (void *)info->hdr + sechdr->sh_offset + offset;
> +}
> +
> #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
>
> static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
> @@ -697,10 +709,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
> unsigned int *crcp;
>
> /* symbol points to the CRC in the ELF object */
> - crcp = (void *)info->hdr + sym->st_value +
> - info->sechdrs[sym->st_shndx].sh_offset -
> - (info->hdr->e_type != ET_REL ?
> - info->sechdrs[sym->st_shndx].sh_addr : 0);
> + crcp = sym_get_data(info, sym);
> crc = TO_NATIVE(*crcp);
> }
> sym_update_crc(symname + strlen("__crc_"), mod, crc,
> --
> 2.17.1
>
--
Best Regards
Masahiro Yamada
