[PATCH 07/11] objtool: Convert ANNOTATE_INTRA_FUNCTION_CALLS to ANNOTATE

Peter Zijlstra
2023-12-04T09:40:39Z

include/linux/objtool.h | 16 ++----
include/linux/objtool_types.h | 1
tools/include/linux/objtool_types.h | 1
tools/objtool/check.c | 96 ++++++++++++++----------------------
4 files changed, 47 insertions(+), 67 deletions(-)

--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -66,16 +66,6 @@
#else /* __ASSEMBLY__ */

/*
- * This macro indicates that the following intra-function call is valid.
- * Any non-annotated intra-function call will cause objtool to issue a warning.
- */
-#define ANNOTATE_INTRA_FUNCTION_CALL \
- 999: \
- .pushsection .discard.intra_function_calls; \
- .long 999b; \
- .popsection;
-
-/*
* In asm, there are two kinds of code: normal C-type callable functions and
* the rest. The normal callable functions can be called by other code, and
* don't do anything unusual with the stack. Such normal callable functions
@@ -152,6 +142,12 @@

#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR

+/*
+ * This macro indicates that the following intra-function call is valid.
+ * Any non-annotated intra-function call will cause objtool to issue a warning.
+ */
+#define ANNOTATE_INTRA_FUNCTION_CALL ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALLS
+
#endif /* __ASSEMBLY__ */

#else /* !CONFIG_OBJTOOL */
--- a/include/linux/objtool_types.h
+++ b/include/linux/objtool_types.h
@@ -63,5 +63,6 @@ struct unwind_hint {
#define ANNOTYPE_INSTR_END 4
#define ANNOTYPE_UNRET_BEGIN 5
#define ANNOTYPE_IGNORE_ALTS 6
+#define ANNOTYPE_INTRA_FUNCTION_CALLS 7

#endif /* _LINUX_OBJTOOL_TYPES_H */
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -63,5 +63,6 @@ struct unwind_hint {
#define ANNOTYPE_INSTR_END 4
#define ANNOTYPE_UNRET_BEGIN 5
#define ANNOTYPE_IGNORE_ALTS 6
+#define ANNOTYPE_INTRA_FUNCTION_CALLS 7

#endif /* _LINUX_OBJTOOL_TYPES_H */
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2274,7 +2274,8 @@ static int read_unwind_hints(struct objt
return 0;
}

-static int read_annotate(struct objtool_file *file, int (*func)(int type, struct instruction *insn))
+static int read_annotate(struct objtool_file *file,
+ int (*func)(struct objtool_file *file, int type, struct instruction *insn))
{
struct section *rsec, *sec;
struct instruction *insn;
@@ -2299,7 +2300,7 @@ static int read_annotate(struct objtool_

type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * sec->sh.sh_entsize) + 4);

- ret = func(type, insn);
+ ret = func(file, type, insn);
if (ret < 0)
return ret;
}
@@ -2307,7 +2308,7 @@ static int read_annotate(struct objtool_
return 0;
}

-static int __annotate_ignore_alts(int type, struct instruction *insn)
+static int __annotate_ignore_alts(struct objtool_file *file, int type, struct instruction *insn)
{
if (type != ANNOTYPE_IGNORE_ALTS)
return 0;
@@ -2316,7 +2317,7 @@ static int __annotate_ignore_alts(int ty
return 0;
}

-static int __annotate_noendbr(int type, struct instruction *insn)
+static int __annotate_noendbr(struct objtool_file *file, int type, struct instruction *insn)
{
if (type != ANNOTYPE_NOENDBR)
return 0;
@@ -2325,7 +2326,37 @@ static int __annotate_noendbr(int type,
return 0;
}

-static int __annotate_retpoline_safe(int type, struct instruction *insn)
+static int __annotate_ifc(struct objtool_file *file, int type, struct instruction *insn)
+{
+ unsigned long dest_off;
+
+ if (type != ANNOTYPE_INTRA_FUNCTION_CALLS)
+ return 0;
+
+ if (insn->type != INSN_CALL) {
+ WARN_INSN(insn, "intra_function_call not a direct call");
+ return -1;
+ }
+
+ /*
+ * Treat intra-function CALLs as JMPs, but with a stack_op.
+ * See add_call_destinations(), which strips stack_ops from
+ * normal CALLs.
+ */
+ insn->type = INSN_JUMP_UNCONDITIONAL;
+
+ dest_off = arch_jump_destination(insn);
+ insn->jump_dest = find_insn(file, insn->sec, dest_off);
+ if (!insn->jump_dest) {
+ WARN_INSN(insn, "can't find call dest at %s+0x%lx",
+ insn->sec->name, dest_off);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int __annotate_retpoline_safe(struct objtool_file *file, int type, struct instruction *insn)
{
if (type != ANNOTYPE_RETPOLINE_SAFE)
return 0;
@@ -2342,7 +2373,7 @@ static int __annotate_retpoline_safe(int
return 0;
}

-static int __annotate_instr(int type, struct instruction *insn)
+static int __annotate_instr(struct objtool_file *file, int type, struct instruction *insn)
{
switch (type) {
case ANNOTYPE_INSTR_BEGIN:
@@ -2360,7 +2391,7 @@ static int __annotate_instr(int type, st
return 0;
}

-static int __annotate_unret(int type, struct instruction *insn)
+static int __annotate_unret(struct objtool_file *file, int type, struct instruction *insn)
{
if (type != ANNOTYPE_UNRET_BEGIN)
return 0;
@@ -2370,55 +2401,6 @@ static int __annotate_unret(int type, st

}

-static int read_intra_function_calls(struct objtool_file *file)
-{
- struct instruction *insn;
- struct section *rsec;
- struct reloc *reloc;
-
- rsec = find_section_by_name(file->elf, ".rela.discard.intra_function_calls");
- if (!rsec)
- return 0;
-
- for_each_reloc(rsec, reloc) {
- unsigned long dest_off;
-
- if (reloc->sym->type != STT_SECTION) {
- WARN("unexpected relocation symbol type in %s",
- rsec->name);
- return -1;
- }
-
- insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
- if (!insn) {
- WARN("bad .discard.intra_function_call entry");
- return -1;
- }
-
- if (insn->type != INSN_CALL) {
- WARN_INSN(insn, "intra_function_call not a direct call");
- return -1;
- }
-
- /*
- * Treat intra-function CALLs as JMPs, but with a stack_op.
- * See add_call_destinations(), which strips stack_ops from
- * normal CALLs.
- */
- insn->type = INSN_JUMP_UNCONDITIONAL;
-
- dest_off = arch_jump_destination(insn);
- insn->jump_dest = find_insn(file, insn->sec, dest_off);
- if (!insn->jump_dest) {
- WARN_INSN(insn, "can't find call dest at %s+0x%lx",
- insn->sec->name, dest_off);
- return -1;
- }
- }
-
- return 0;
-}
-
/*
* Return true if name matches an instrumentation function, where calls to that
* function from noinstr code can safely be removed, but compilers won't do so.
@@ -2554,7 +2536,7 @@ static int decode_sections(struct objtoo
* Must be before add_call_destination(); it changes INSN_CALL to
* INSN_JUMP.
*/
- ret = read_intra_function_calls(file);
+ ret = read_annotate(file, __annotate_ifc);
if (ret)
return ret;