[PATCH 5/7] objtool: Clean up elf_write() condition

Peter Zijlstra
2020-06-18T14:51:15Z

With there being multiple ways to change the ELF data, let's more
concisely track modification.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
tools/objtool/check.c | 4 +++-
tools/objtool/elf.c | 13 +++++++++++--
tools/objtool/elf.h | 5 +++--
tools/objtool/orc_gen.c | 2 +-
4 files changed, 18 insertions(+), 6 deletions(-)

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2740,7 +2740,7 @@ int check(const char *_objname, bool orc

objname = _objname;

- file.elf = elf_open_read(objname, orc ? O_RDWR : O_RDONLY);
+ file.elf = elf_open_read(objname, O_RDWR);
if (!file.elf)
return 1;

@@ -2801,7 +2801,9 @@ 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
@@ -747,6 +747,8 @@ 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;
}

@@ -880,11 +882,14 @@ static int elf_rebuild_rela_reloc_sectio
return 0;
}

-int elf_rebuild_reloc_section(struct section *sec)
+int elf_rebuild_reloc_section(struct elf *elf, struct section *sec)
{
struct reloc *reloc;
int nr;

+ sec->changed = true;
+ elf->changed = true;
+
nr = 0;
list_for_each_entry(reloc, &sec->reloc_list, list)
nr++;
@@ -896,7 +901,7 @@ int elf_rebuild_reloc_section(struct sec
}
}

-int elf_write(const struct elf *elf)
+int elf_write(struct elf *elf)
{
struct section *sec;
Elf_Scn *s;
@@ -913,6 +918,8 @@ int elf_write(const struct elf *elf)
WARN_ELF("gelf_update_shdr");
return -1;
}
+
+ sec->changed = false;
}
}

@@ -925,6 +932,8 @@ 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);
@@ -133,7 +134,7 @@ struct reloc *find_reloc_by_dest(const s
struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len);
struct symbol *find_func_containing(struct section *sec, unsigned long offset);
-int elf_rebuild_reloc_section(struct section *sec);
+int elf_rebuild_reloc_section(struct elf *elf, struct section *sec);

#define for_each_sec(file, sec) \
list_for_each_entry(sec, &file->elf->sections, list)
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -222,7 +222,7 @@ int create_orc_sections(struct objtool_f
}
}

- if (elf_rebuild_reloc_section(ip_relocsec))
+ if (elf_rebuild_reloc_section(file->elf, ip_relocsec))
return -1;

return 0;