On Fri, Jun 12, 2020 at 04:30:35PM +0200, Peter Zijlstra wrote:
> With there being multiple ways to change the ELF data, let's more
> concisely track modification.
>
> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Would it make sense to set the relocation section's "changed" flag in
addition to the elf struct's changed flag in elf_rebuild_reloc_section()?
Right now I think the code is assuming that it's a newly created section
but it would be more defensive to set it during a rebuild too I think.
Otherwise looks good to me.
> ---
> tools/objtool/check.c | 2 ++
> tools/objtool/elf.c | 8 +++++++-
> tools/objtool/elf.h | 3 ++-
> 3 files changed, 11 insertions(+), 2 deletions(-)
>
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -2779,7 +2779,9 @@ int check(const char *_objname, bool orc
> ret = create_orc_sections(&file);
> if (ret < 0)
> goto out;
> + }
>
> + if (file.elf->changed) {
> ret = elf_write(file.elf);
> if (ret < 0)
> goto out;
> --- a/tools/objtool/elf.c
> +++ b/tools/objtool/elf.c
> @@ -746,6 +746,8 @@ struct section *elf_create_section(struc
> elf_hash_add(elf->section_hash, &sec->hash, sec->idx);
> elf_hash_add(elf->section_name_hash, &sec->name_hash,
> str_hash(sec->name));
>
> + elf->changed = true;
> +
> return sec;
> }
>
> @@ -862,7 +864,7 @@ int elf_rebuild_reloc_section(struct sec
> return elf_rebuild_rela_section(sec, nr);
> }
>
> -int elf_write(const struct elf *elf)
> +int elf_write(struct elf *elf)
> {
> struct section *sec;
> Elf_Scn *s;
> @@ -879,6 +881,8 @@ int elf_write(const struct elf *elf)
> WARN_ELF("gelf_update_shdr");
> return -1;
> }
> +
> + sec->changed = false;
> }
> }
>
> @@ -891,6 +895,8 @@ int elf_write(const struct elf *elf)
> return -1;
> }
>
> + elf->changed = false;
> +
> return 0;
> }
>
> --- a/tools/objtool/elf.h
> +++ b/tools/objtool/elf.h
> @@ -79,6 +79,7 @@ struct elf {
> Elf *elf;
> GElf_Ehdr ehdr;
> int fd;
> + bool changed;
> char *name;
> struct list_head sections;
> DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS);
> @@ -121,7 +122,7 @@ struct elf *elf_open_read(const char *na
> struct section *elf_create_section(struct elf *elf, const char *name, size_t
> entsize, int nr);
> struct section *elf_create_reloc_section(struct elf *elf, struct section
> *base, int reltype);
> void elf_add_reloc(struct elf *elf, struct reloc *reloc);
> -int elf_write(const struct elf *elf);
> +int elf_write(struct elf *elf);
> void elf_close(struct elf *elf);
>
> struct section *find_section_by_name(const struct elf *elf, const char
> *name);
>
>
