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Subject[PATCH v6 09/33] objtool: check: Support data in text section
Date
Arm64 assembly code can mix code and data in text sections through the use
of SYM_DATA_*() macros. Skip the content of these symbols when decoding
instructions of text sections.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
tools/objtool/check.c | 14 ++++++++++++--
tools/objtool/elf.c | 14 ++++++++++++++
tools/objtool/include/objtool/elf.h | 1 +
3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index c0feb6db7c6d..f19ea3fc1e6b 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -359,7 +359,7 @@ static int decode_instructions(struct objtool_file *file)
{
struct section *sec;
struct symbol *func;
- unsigned long offset;
+ unsigned long offset, next_offset;
struct instruction *insn;
int ret;

@@ -377,7 +377,15 @@ static int decode_instructions(struct objtool_file *file)
!strcmp(sec->name, ".entry.text"))
sec->noinstr = true;

- for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
+ for (offset = 0; offset < sec->sh.sh_size; offset = next_offset) {
+ struct symbol *obj_sym = find_object_containing(sec, offset);
+
+ if (obj_sym) {
+ /* This is data in the middle of text section, skip it */
+ next_offset = obj_sym->offset + obj_sym->len;
+ continue;
+ }
+
insn = malloc(sizeof(*insn));
if (!insn) {
WARN("malloc failed");
@@ -410,6 +418,8 @@ static int decode_instructions(struct objtool_file *file)
hash_add(file->insn_hash, &insn->hash, sec_offset_hash(sec, insn->offset));
list_add_tail(&insn->list, &file->insn_list);
nr_insns++;
+
+ next_offset = offset + insn->len;
}

list_for_each_entry(func, &sec->symbol_list, list) {
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index c25e957c1e52..d7304e39f6b6 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -236,6 +236,20 @@ struct symbol *find_func_containing(struct section *sec, unsigned long offset)
return NULL;
}

+struct symbol *find_object_containing(const struct section *sec, unsigned long offset)
+{
+ struct rb_node *node;
+
+ rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) {
+ struct symbol *s = rb_entry(node, struct symbol, node);
+
+ if (s->type == STT_OBJECT)
+ return s;
+ }
+
+ return NULL;
+}
+
struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)
{
struct symbol *sym;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index adebfbc2b518..8b0896935af1 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -167,6 +167,7 @@ struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, uns
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);
+struct symbol *find_object_containing(const struct section *sec, unsigned long offset);

#define for_each_sec(file, sec) \
list_for_each_entry(sec, &file->elf->sections, list)
--
2.17.1
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