In preparation for the objtool klp diff subcommand, refactor
elf_add_string() by adding a new elf_add_data() helper which allows the
adding of arbitrary data to a section.
Make both interfaces public so they can be used by the upcoming klp diff
code.
Signed-off-by: Josh Poimboeuf <jpoim...@kernel.org>
---
tools/objtool/elf.c | 66 ++++++++++++++++++++---------
tools/objtool/include/objtool/elf.h | 10 +++--
2 files changed, 54 insertions(+), 22 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 4f56ea426683..535bdcf077d0 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -18,10 +18,11 @@
#include <errno.h>
#include <linux/interval_tree_generic.h>
#include <objtool/builtin.h>
-
#include <objtool/elf.h>
#include <objtool/warn.h>
+#define ALIGN_UP(x, align_to) (((x) + ((align_to)-1)) & ~((align_to)-1))
+
static inline u32 str_hash(const char *str)
{
return jhash(str, strlen(str), 0);
@@ -760,8 +761,6 @@ static int elf_update_symbol(struct elf *elf, struct
section *symtab,
return 0;
}
-static int elf_add_string(struct elf *elf, struct section *strtab, const char
*str);
-
struct symbol *elf_create_symbol(struct elf *elf, const char *name,
struct section *sec, unsigned int bind,
unsigned int type, unsigned long offset,
@@ -1097,11 +1096,9 @@ struct elf *elf_open_read(const char *name, int flags)
return NULL;
}
-static int elf_add_string(struct elf *elf, struct section *strtab, const char
*str)
+unsigned int elf_add_string(struct elf *elf, struct section *strtab, const
char *str)
{
- Elf_Data *data;
- Elf_Scn *s;
- int len;
+ unsigned int offset;
if (!strtab)
strtab = find_section_by_name(elf, ".strtab");
@@ -1110,28 +1107,59 @@ static int elf_add_string(struct elf *elf, struct
section *strtab, const char *s
return -1;
}
- s = elf_getscn(elf->elf, strtab->idx);
+ if (!strtab->sh.sh_addralign) {
+ ERROR("'%s': invalid sh_addralign", strtab->name);
+ return -1;
+ }
+
+ offset = ALIGN_UP(strtab->sh.sh_size, strtab->sh.sh_addralign);
+
+ if (!elf_add_data(elf, strtab, str, strlen(str) + 1))
+ return -1;
+
+ return offset;
+}
+
+void *elf_add_data(struct elf *elf, struct section *sec, const void *data,
size_t size)
+{
+ unsigned long offset;
+ Elf_Scn *s;
+
+ if (!sec->sh.sh_addralign) {
+ ERROR("'%s': invalid sh_addralign", sec->name);
+ return NULL;
+ }
+
+ s = elf_getscn(elf->elf, sec->idx);
if (!s) {
ERROR_ELF("elf_getscn");
- return -1;
+ return NULL;
}
- data = elf_newdata(s);
- if (!data) {
+ sec->data = elf_newdata(s);
+ if (!sec->data) {
ERROR_ELF("elf_newdata");
- return -1;
+ return NULL;
}
- data->d_buf = strdup(str);
- data->d_size = strlen(str) + 1;
- data->d_align = 1;
+ sec->data->d_buf = calloc(1, size);
+ if (!sec->data->d_buf) {
+ ERROR_GLIBC("calloc");
+ return NULL;
+ }
- len = strtab->sh.sh_size;
- strtab->sh.sh_size += data->d_size;
+ if (data)
+ memcpy(sec->data->d_buf, data, size);
- mark_sec_changed(elf, strtab, true);
+ sec->data->d_size = size;
+ sec->data->d_align = 1;
- return len;
+ offset = ALIGN_UP(sec->sh.sh_size, sec->sh.sh_addralign);
+ sec->sh.sh_size = offset + size;
+
+ mark_sec_changed(elf, sec, true);
+
+ return sec->data->d_buf;
}
struct section *elf_create_section(struct elf *elf, const char *name,
diff --git a/tools/objtool/include/objtool/elf.h
b/tools/objtool/include/objtool/elf.h
index b366516b119d..fc00f86bedba 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -134,6 +134,10 @@ struct symbol *elf_create_section_symbol(struct elf *elf,
struct section *sec);
struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig,
size_t size);
+void *elf_add_data(struct elf *elf, struct section *sec, const void *data,
+ size_t size);
+
+unsigned int elf_add_string(struct elf *elf, struct section *strtab, const
char *str);
struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
unsigned long offset,
@@ -147,9 +151,9 @@ struct reloc *elf_init_reloc_data_sym(struct elf *elf,
struct section *sec,
struct symbol *sym,
s64 addend);
-int elf_write_insn(struct elf *elf, struct section *sec,
- unsigned long offset, unsigned int len,
- const char *insn);
+int elf_write_insn(struct elf *elf, struct section *sec, unsigned long offset,
+ unsigned int len, const char *insn);
+
int elf_write(struct elf *elf);
void elf_close(struct elf *elf);
--
2.49.0
