objtool: Add helper macros for traversing instructions
Add some helper macros to make it easier to traverse instructions, and
to abstract the details of the instruction list implementation in
preparation for creating a hash structure.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/8e1715d5035bc02b4db28d0fccef6bb1170d1f12.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index fe24804..46a8985 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -66,9 +66,8 @@
const char *objname;
static bool nofp;
-static struct instruction *find_instruction(struct objtool_file *file,
- struct section *sec,
- unsigned long offset)
+static struct instruction *find_insn(struct objtool_file *file,
+ struct section *sec, unsigned long offset)
{
struct instruction *insn;
@@ -79,6 +78,31 @@
return NULL;
}
+static struct instruction *next_insn_same_sec(struct objtool_file *file,
+ struct instruction *insn)
+{
+ struct instruction *next = list_next_entry(insn, list);
+
+ if (&next->list == &file->insns || next->sec != insn->sec)
+ return NULL;
+
+ return next;
+}
+
+#define for_each_insn(file, insn) \
+ list_for_each_entry(insn, &file->insns, list)
+
+#define func_for_each_insn(file, func, insn) \
+ for (insn = find_insn(file, func->sec, func->offset); \
+ insn && &insn->list != &file->insns && \
+ insn->sec == func->sec && \
+ insn->offset < func->offset + func->len; \
+ insn = list_next_entry(insn, list))
+
+#define sec_for_each_insn_from(file, insn) \
+ for (; insn; insn = next_insn_same_sec(file, insn))
+
+
/*
* Check if the function has been manually whitelisted with the
* STACK_FRAME_NON_STANDARD macro, or if it should be automatically whitelisted
@@ -99,16 +123,9 @@
return true;
/* check if it has a context switching instruction */
- insn = find_instruction(file, func->sec, func->offset);
- if (!insn)
- return false;
- list_for_each_entry_from(insn, &file->insns, list) {
- if (insn->sec != func->sec ||
- insn->offset >= func->offset + func->len)
- break;
+ func_for_each_insn(file, func, insn)
if (insn->type == INSN_CONTEXT_SWITCH)
return true;
- }
return false;
}
@@ -131,7 +148,7 @@
int recursion)
{
int i;
- struct instruction *insn, *func_insn;
+ struct instruction *insn;
bool empty = true;
/*
@@ -160,16 +177,7 @@
if (!func->sec)
return 0;
- func_insn = find_instruction(file, func->sec, func->offset);
- if (!func_insn)
- return 0;
-
- insn = func_insn;
- list_for_each_entry_from(insn, &file->insns, list) {
- if (insn->sec != func->sec ||
- insn->offset >= func->offset + func->len)
- break;
-
+ func_for_each_insn(file, func, insn) {
empty = false;
if (insn->type == INSN_RETURN)
@@ -184,8 +192,7 @@
* case, the function's dead-end status depends on whether the target
* of the sibling call returns.
*/
- insn = func_insn;
- list_for_each_entry_from(insn, &file->insns, list) {
+ func_for_each_insn(file, func, insn) {
if (insn->sec != func->sec ||
insn->offset >= func->offset + func->len)
break;
@@ -294,17 +301,8 @@
if (!ignore_func(file, func))
continue;
- insn = find_instruction(file, sec, func->offset);
- if (!insn)
- continue;
-
- list_for_each_entry_from(insn, &file->insns, list) {
- if (insn->sec != func->sec ||
- insn->offset >= func->offset + func->len)
- break;
-
+ func_for_each_insn(file, func, insn)
insn->visited = true;
- }
}
}
}
@@ -319,7 +317,7 @@
struct section *dest_sec;
unsigned long dest_off;
- list_for_each_entry(insn, &file->insns, list) {
+ for_each_insn(file, insn) {
if (insn->type != INSN_JUMP_CONDITIONAL &&
insn->type != INSN_JUMP_UNCONDITIONAL)
continue;
@@ -345,7 +343,7 @@
continue;
}
- insn->jump_dest = find_instruction(file, dest_sec, dest_off);
+ insn->jump_dest = find_insn(file, dest_sec, dest_off);
if (!insn->jump_dest) {
/*
@@ -375,7 +373,7 @@
unsigned long dest_off;
struct rela *rela;
- list_for_each_entry(insn, &file->insns, list) {
+ for_each_insn(file, insn) {
if (insn->type != INSN_CALL)
continue;
@@ -438,9 +436,8 @@
last_orig_insn = NULL;
insn = orig_insn;
- list_for_each_entry_from(insn, &file->insns, list) {
- if (insn->sec != special_alt->orig_sec ||
- insn->offset >= special_alt->orig_off + special_alt->orig_len)
+ sec_for_each_insn_from(file, insn) {
+ if (insn->offset >= special_alt->orig_off + special_alt->orig_len)
break;
if (special_alt->skip_orig)
@@ -450,8 +447,7 @@
last_orig_insn = insn;
}
- if (list_is_last(&last_orig_insn->list, &file->insns) ||
- list_next_entry(last_orig_insn, list)->sec != special_alt->orig_sec) {
+ if (!next_insn_same_sec(file, last_orig_insn)) {
WARN("%s: don't know how to handle alternatives at end of section",
special_alt->orig_sec->name);
return -1;
@@ -476,9 +472,8 @@
last_new_insn = NULL;
insn = *new_insn;
- list_for_each_entry_from(insn, &file->insns, list) {
- if (insn->sec != special_alt->new_sec ||
- insn->offset >= special_alt->new_off + special_alt->new_len)
+ sec_for_each_insn_from(file, insn) {
+ if (insn->offset >= special_alt->new_off + special_alt->new_len)
break;
last_new_insn = insn;
@@ -561,8 +556,8 @@
goto out;
}
- orig_insn = find_instruction(file, special_alt->orig_sec,
- special_alt->orig_off);
+ orig_insn = find_insn(file, special_alt->orig_sec,
+ special_alt->orig_off);
if (!orig_insn) {
WARN_FUNC("special: can't find orig instruction",
special_alt->orig_sec, special_alt->orig_off);
@@ -572,8 +567,8 @@
new_insn = NULL;
if (!special_alt->group || special_alt->new_len) {
- new_insn = find_instruction(file, special_alt->new_sec,
- special_alt->new_off);
+ new_insn = find_insn(file, special_alt->new_sec,
+ special_alt->new_off);
if (!new_insn) {
WARN_FUNC("special: can't find new instruction",
special_alt->new_sec,
@@ -619,7 +614,7 @@
struct symbol *func;
struct alternative *alt;
- list_for_each_entry(insn, &file->insns, list) {
+ for_each_insn(file, insn) {
if (insn->type != INSN_JUMP_DYNAMIC)
continue;
@@ -655,8 +650,7 @@
rela->addend >= func->offset + func->len)
break;
- alt_insn = find_instruction(file, insn->sec,
- rela->addend);
+ alt_insn = find_insn(file, insn->sec, rela->addend);
if (!alt_insn) {
WARN("%s: can't find instruction at %s+0x%x",
rodata->rela->name, insn->sec->name,
@@ -881,9 +875,8 @@
break;
}
- insn = list_next_entry(insn, list);
-
- if (&insn->list == &file->insns || insn->sec != sec) {
+ insn = next_insn_same_sec(file, insn);
+ if (!insn) {
WARN("%s: unexpected end of section", sec->name);
warnings++;
return warnings;
@@ -934,8 +927,8 @@
"__ubsan_handle_builtin_unreachable"));
}
-static bool ignore_unreachable_insn(struct instruction *insn,
- unsigned long func_end)
+static bool ignore_unreachable_insn(struct symbol *func,
+ struct instruction *insn)
{
int i;
@@ -961,7 +954,7 @@
continue;
}
- if (insn->offset + insn->len >= func_end)
+ if (insn->offset + insn->len >= func->offset + func->len)
break;
insn = list_next_entry(insn, list);
}
@@ -974,7 +967,6 @@
struct section *sec;
struct symbol *func;
struct instruction *insn;
- unsigned long func_end;
int ret, warnings = 0;
list_for_each_entry(sec, &file->elf->sections, list) {
@@ -982,7 +974,7 @@
if (func->type != STT_FUNC)
continue;
- insn = find_instruction(file, sec, func->offset);
+ insn = find_insn(file, sec, func->offset);
if (!insn) {
WARN("%s(): can't find starting instruction",
func->name);
@@ -1000,21 +992,11 @@
if (func->type != STT_FUNC)
continue;
- insn = find_instruction(file, sec, func->offset);
- if (!insn)
- continue;
-
- func_end = func->offset + func->len;
-
- list_for_each_entry_from(insn, &file->insns, list) {
- if (insn->sec != func->sec ||
- insn->offset >= func_end)
- break;
-
+ func_for_each_insn(file, func, insn) {
if (insn->visited)
continue;
- if (!ignore_unreachable_insn(insn, func_end)) {
+ if (!ignore_unreachable_insn(func, insn)) {
WARN_FUNC("function has unreachable instruction", insn->sec, insn->offset);
warnings++;
}
@@ -1032,7 +1014,7 @@
struct instruction *insn;
int warnings = 0;
- list_for_each_entry(insn, &file->insns, list) {
+ for_each_insn(file, insn) {
if (!insn->visited && insn->type == INSN_RETURN) {
WARN_FUNC("return instruction outside of a callable function",
insn->sec, insn->offset);