| Message ID | 20191114174226.7201-1-yamada.masahiro@socionext.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/6] modpost: add a helper to get data pointed by a symbol | expand |
(+CC: Matthias, who might be interested) On Fri, Nov 15, 2019 at 2:42 AM Masahiro Yamada <yamada.masahiro@socionext.com> 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@socionext.com> > --- > > 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 >
On Fri, Nov 15, 2019 at 2:42 AM Masahiro Yamada <yamada.masahiro@socionext.com> 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@socionext.com> > --- Series, applied to linux-kbuild. > > 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 >
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,
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@socionext.com> --- scripts/mod/modpost.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)