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Message-ID: <176060834932.709179.12492204513424237168.tip-bot2@tip-bot2>
Date: Thu, 16 Oct 2025 09:52:29 -0000
From: "tip-bot2 for Josh Poimboeuf" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Petr Mladek <pmladek@...e.com>, Joe Lawrence <joe.lawrence@...hat.com>,
Josh Poimboeuf <jpoimboe@...nel.org>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: objtool/core] objtool: Add elf_create_data()
The following commit has been merged into the objtool/core branch of tip:
Commit-ID: 431dbabf2d9dd27cd597a9d1d4611e7ae64bf8bd
Gitweb: https://git.kernel.org/tip/431dbabf2d9dd27cd597a9d1d4611e7ae64bf8bd
Author: Josh Poimboeuf <jpoimboe@...nel.org>
AuthorDate: Wed, 17 Sep 2025 09:03:49 -07:00
Committer: Josh Poimboeuf <jpoimboe@...nel.org>
CommitterDate: Tue, 14 Oct 2025 14:46:48 -07:00
objtool: Add elf_create_data()
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 global so they can be used by the upcoming klp diff
code.
Acked-by: Petr Mladek <pmladek@...e.com>
Tested-by: Joe Lawrence <joe.lawrence@...hat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.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 7a7e63c..117a1b5 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);
@@ -763,8 +764,6 @@ 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,
@@ -1100,11 +1099,9 @@ err:
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");
@@ -1113,28 +1110,59 @@ 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;
+
+ offset = ALIGN_UP(sec->sh.sh_size, sec->sh.sh_addralign);
+ sec->sh.sh_size = offset + size;
+
+ mark_sec_changed(elf, sec, true);
- return len;
+ 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 badb109..0d9aeef 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -135,6 +135,10 @@ 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,
@@ -148,9 +152,9 @@ 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);
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