[PATCH 43/48] objtool: Add insn_sym() helper

Josh Poimboeuf
2026-04-23T04:04:46Z

Alternative replacement instructions awkwardly have insn->sym set to the
function they get patched to rather than the symbol (or rather lack
thereof) they belong to in the file.

This makes it difficult to know where a given instruction actually
lives.

Add a new insn_sym() helper which preserves the existing semantic of
insn->sym. Rename insn->sym to insn->_sym, which contains the actual
ELF binary symbol (or NULL, for alternative replacements) an instruction
lives in.

The private insn->_sym value will be needed for a subsequent patch.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 31 ++++++++++++---------------
tools/objtool/disas.c | 22 +++++++++----------
tools/objtool/include/objtool/check.h | 19 ++++++++++++++--
tools/objtool/include/objtool/warn.h | 6 +++---
tools/objtool/trace.c | 8 +++----
5 files changed, 48 insertions(+), 38 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index ae047be919c5..410061aeed26 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -495,7 +495,7 @@ static int decode_instructions(struct objtool_file *file)
}

sym_for_each_insn(file, func, insn) {
- insn->sym = func;
+ insn->_sym = func;
if (is_func_sym(func) &&
insn->type == INSN_ENDBR &&
list_empty(&insn->call_node)) {
@@ -859,15 +859,14 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file)
list_for_each_entry(insn, &file->endbr_list, call_node) {

int *site = (int *)sec->data->d_buf + idx;
- struct symbol *sym = insn->sym;
+ struct symbol *func = insn_func(insn);
*site = 0;

- if (opts.module && sym && is_func_sym(sym) &&
- insn->offset == sym->offset &&
- (!strcmp(sym->name, "init_module") ||
- !strcmp(sym->name, "cleanup_module"))) {
+ if (opts.module && func && insn->offset == func->offset &&
+ (!strcmp(func->name, "init_module") ||
+ !strcmp(func->name, "cleanup_module"))) {
ERROR("%s(): Magic init_module() function name is deprecated, use module_init(fn) instead",
- sym->name);
+ func->name);
return -1;
}

@@ -1581,7 +1580,7 @@ static int add_jump_destinations(struct objtool_file *file)
}

if (!dest_sym || is_sec_sym(dest_sym)) {
- dest_sym = dest_insn->sym;
+ dest_sym = insn_sym(dest_insn);
if (!dest_sym)
goto set_jump_dest;
}
@@ -1597,7 +1596,7 @@ static int add_jump_destinations(struct objtool_file *file)
continue;
}

- if (!insn->sym || insn->sym->pfunc == dest_sym->pfunc)
+ if (!insn_sym(insn) || insn_sym(insn)->pfunc == dest_sym->pfunc)
goto set_jump_dest;

/*
@@ -1770,7 +1769,6 @@ static int handle_group_alt(struct objtool_file *file,
nop->offset = special_alt->new_off + special_alt->new_len;
nop->len = special_alt->orig_len - special_alt->new_len;
nop->type = INSN_NOP;
- nop->sym = orig_insn->sym;
nop->alt_group = new_alt_group;
nop->fake = 1;
}
@@ -1789,7 +1787,6 @@ static int handle_group_alt(struct objtool_file *file,

last_new_insn = insn;

- insn->sym = orig_insn->sym;
insn->alt_group = new_alt_group;

/*
@@ -2432,12 +2429,12 @@ static int __annotate_late(struct objtool_file *file, int type, struct instructi
break;

case ANNOTYPE_NOCFI:
- sym = insn->sym;
+ sym = insn_sym(insn);
if (!sym) {
ERROR_INSN(insn, "dodgy NOCFI annotation");
return -1;
}
- insn->sym->nocfi = 1;
+ insn_sym(insn)->nocfi = 1;
break;

default:
@@ -2538,7 +2535,7 @@ static void mark_holes(struct objtool_file *file)
* favour of a regular symbol, but leaves the code in place.
*/
for_each_insn(file, insn) {
- if (insn->sym || !find_symbol_hole_containing(insn->sec, insn->offset)) {
+ if (insn_sym(insn) || !find_symbol_hole_containing(insn->sec, insn->offset)) {
in_hole = false;
continue;
}
@@ -2982,7 +2979,7 @@ static int update_cfi_state(struct instruction *insn,
}

if (op->dest.reg == CFI_BP && op->src.reg == CFI_SP &&
- insn->sym->frame_pointer) {
+ insn_sym(insn)->frame_pointer) {
/* addi.d fp,sp,imm on LoongArch */
if (cfa->base == CFI_SP && cfa->offset == op->src.offset) {
cfa->base = CFI_BP;
@@ -2994,7 +2991,7 @@ static int update_cfi_state(struct instruction *insn,
if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) {
/* addi.d sp,fp,imm on LoongArch */
if (cfa->base == CFI_BP && cfa->offset == 0) {
- if (insn->sym->frame_pointer) {
+ if (insn_sym(insn)->frame_pointer) {
cfa->base = CFI_SP;
cfa->offset = -op->src.offset;
}
@@ -4171,7 +4168,7 @@ static int validate_retpoline(struct objtool_file *file)
* broken.
*/
list_for_each_entry(insn, &file->retpoline_call_list, call_node) {
- struct symbol *sym = insn->sym;
+ struct symbol *sym = insn_sym(insn);

if (sym && (is_notype_sym(sym) ||
is_func_sym(sym)) && !sym->nocfi) {
diff --git a/tools/objtool/disas.c b/tools/objtool/disas.c
index 59090234af19..e6a54a83605c 100644
--- a/tools/objtool/disas.c
+++ b/tools/objtool/disas.c
@@ -210,7 +210,7 @@ static bool disas_print_addr_alt(bfd_vma addr, struct disassemble_info *dinfo)
offset = addr - alt_group->first_insn->offset;

addr = orig_first_insn->offset + offset;
- sym = orig_first_insn->sym;
+ sym = insn_sym(orig_first_insn);

disas_print_addr_sym(orig_first_insn->sec, sym, addr, dinfo);

@@ -222,15 +222,13 @@ static void disas_print_addr_noreloc(bfd_vma addr,
{
struct disas_context *dctx = dinfo->application_data;
struct instruction *insn = dctx->insn;
- struct symbol *sym = NULL;
+ struct symbol *sym = insn_sym(insn);

if (disas_print_addr_alt(addr, dinfo))
return;

- if (insn->sym && addr >= insn->sym->offset &&
- addr < insn->sym->offset + insn->sym->len) {
- sym = insn->sym;
- }
+ if (sym && (addr < sym->offset || addr >= sym->offset + sym->len))
+ sym = NULL;

disas_print_addr_sym(insn->sec, sym, addr, dinfo);
}
@@ -291,9 +289,9 @@ static void disas_print_address(bfd_vma addr, struct disassemble_info *dinfo)
* up. So check it first.
*/
jump_dest = insn->jump_dest;
- if (jump_dest && jump_dest->sym && jump_dest->offset == addr) {
+ if (jump_dest && insn_sym(jump_dest) && jump_dest->offset == addr) {
if (!disas_print_addr_alt(addr, dinfo))
- disas_print_addr_sym(jump_dest->sec, jump_dest->sym,
+ disas_print_addr_sym(jump_dest->sec, insn_sym(jump_dest),
addr, dinfo);
return;
}
@@ -768,8 +766,8 @@ static int disas_alt_jump(struct disas_alt *dalt)
if (orig_insn->len == 5)
suffix[0] = 'q';
str = strfmt("jmp%-3s %lx <%s+0x%lx>", suffix,
- dest_insn->offset, dest_insn->sym->name,
- dest_insn->offset - dest_insn->sym->offset);
+ dest_insn->offset, insn_sym(dest_insn)->name,
+ dest_insn->offset - insn_sym(dest_insn)->offset);
nops = 0;
} else {
str = strfmt("nop%d", orig_insn->len);
@@ -794,8 +792,8 @@ static int disas_alt_extable(struct disas_alt *dalt)

alt_insn = dalt->alt->insn;
str = strfmt("resume at 0x%lx <%s+0x%lx>",
- alt_insn->offset, alt_insn->sym->name,
- alt_insn->offset - alt_insn->sym->offset);
+ alt_insn->offset, insn_sym(alt_insn)->name,
+ alt_insn->offset - insn_sym(alt_insn)->offset);
if (!str)
return -1;

diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index eea64728d39b..0c53476528a8 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -94,14 +94,29 @@ struct instruction {
};
};
struct alternative *alts;
- struct symbol *sym;
+ struct symbol *_sym;
struct stack_op *stack_ops;
struct cfi_state *cfi;
};

+/*
+ * Return the symbol associated with an instruction. For alternative
+ * replacements, return the symbol of the original code being replaced rather
+ * than NULL. insn->_sym reflects the actual location in the ELF file.
+ */
+static inline struct symbol *insn_sym(struct instruction *insn)
+{
+ struct symbol *sym = insn->_sym;
+
+ if (!sym && insn->alt_group && insn->alt_group->orig_group)
+ sym = insn->alt_group->orig_group->first_insn->_sym;
+
+ return sym;
+}
+
static inline struct symbol *insn_func(struct instruction *insn)
{
- struct symbol *sym = insn->sym;
+ struct symbol *sym = insn_sym(insn);

if (sym && sym->type != STT_FUNC)
sym = NULL;
diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index a9936d60980c..870e147f3a56 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -77,13 +77,13 @@ static inline char *offstr(struct section *sec, unsigned long offset)
#define WARN_INSN(insn, format, ...) \
({ \
struct instruction *_insn = (insn); \
- if (!_insn->sym || !_insn->sym->warned) { \
+ if (!insn_sym(_insn) || !insn_sym(_insn)->warned) { \
WARN_FUNC(_insn->sec, _insn->offset, format, \
##__VA_ARGS__); \
BT_INSN(_insn, ""); \
} \
- if (_insn->sym) \
- _insn->sym->warned = 1; \
+ if (insn_sym(_insn)) \
+ insn_sym(_insn)->warned = 1; \
})

#define BT_INSN(insn, format, ...) \
diff --git a/tools/objtool/trace.c b/tools/objtool/trace.c
index 5dec44dab781..61c6aa302bc3 100644
--- a/tools/objtool/trace.c
+++ b/tools/objtool/trace.c
@@ -169,8 +169,8 @@ void trace_alt_begin(struct instruction *orig_insn, struct alternative *alt,
*/
TRACE_ALT_INFO_NOADDR(orig_insn, "/ ", "%s for instruction at 0x%lx <%s+0x%lx>",
alt_name,
- orig_insn->offset, orig_insn->sym->name,
- orig_insn->offset - orig_insn->sym->offset);
+ orig_insn->offset, insn_sym(orig_insn)->name,
+ orig_insn->offset - insn_sym(orig_insn)->offset);
} else {
TRACE_ALT_INFO_NOADDR(orig_insn, "/ ", "%s", alt_name);
}
@@ -185,8 +185,8 @@ void trace_alt_begin(struct instruction *orig_insn, struct alternative *alt,
if (orig_insn->type == INSN_NOP) {
suffix[0] = (orig_insn->len == 5) ? 'q' : '\0';
TRACE_ADDR(orig_insn, "jmp%-3s %lx <%s+0x%lx>", suffix,
- alt_insn->offset, alt_insn->sym->name,
- alt_insn->offset - alt_insn->sym->offset);
+ alt_insn->offset, insn_sym(alt_insn)->name,
+ alt_insn->offset - insn_sym(alt_insn)->offset);
} else {
TRACE_ADDR(orig_insn, "nop%d", orig_insn->len);
trace_depth--;
--
2.53.0