[RFC PATCH v3 03/22] objtool: Move decode_instructions() to a separate file

madvenka
2023-02-02T07:42:39Z

From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>

check.c implements static stack validation. But decode_instructions() which
resides in it can be shared with other types of validation. E.g., dynamic
FP validation. Move the function to its own file - decode.c.

Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
---
tools/objtool/Build | 1 +
tools/objtool/check.c | 97 ------------------------
tools/objtool/decode.c | 107 +++++++++++++++++++++++++++
tools/objtool/include/objtool/insn.h | 2 +
4 files changed, 110 insertions(+), 97 deletions(-)
create mode 100644 tools/objtool/decode.c

diff --git a/tools/objtool/Build b/tools/objtool/Build
index 1149048e6b3e..8afe56cd0c2d 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -7,6 +7,7 @@ objtool-y += special.o
objtool-y += builtin-check.o
objtool-y += cfi.o
objtool-y += insn.o
+objtool-y += decode.o
objtool-y += elf.o
objtool-y += objtool.o

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index d208086a8a18..be3f6564104a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -169,105 +169,8 @@ static bool dead_end_function(struct objtool_file *file, struct symbol *func)
return __dead_end_function(file, func, 0);
}

-static unsigned long nr_insns;
static unsigned long nr_insns_visited;

-/*
- * Call the arch-specific instruction decoder for all the instructions and add
- * them to the global instruction list.
- */
-static int decode_instructions(struct objtool_file *file)
-{
- struct section *sec;
- struct symbol *func;
- unsigned long offset;
- struct instruction *insn;
- int ret;
-
- for_each_sec(file, sec) {
-
- if (!(sec->sh.sh_flags & SHF_EXECINSTR))
- continue;
-
- if (strcmp(sec->name, ".altinstr_replacement") &&
- strcmp(sec->name, ".altinstr_aux") &&
- strncmp(sec->name, ".discard.", 9))
- sec->text = true;
-
- if (!strcmp(sec->name, ".noinstr.text") ||
- !strcmp(sec->name, ".entry.text") ||
- !strncmp(sec->name, ".text.__x86.", 12))
- sec->noinstr = true;
-
- for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
- insn = malloc(sizeof(*insn));
- if (!insn) {
- WARN("malloc failed");
- return -1;
- }
- memset(insn, 0, sizeof(*insn));
- INIT_LIST_HEAD(&insn->alts);
- INIT_LIST_HEAD(&insn->stack_ops);
- INIT_LIST_HEAD(&insn->call_node);
-
- insn->sec = sec;
- insn->offset = offset;
-
- ret = arch_decode_instruction(file, sec, offset,
- sec->sh.sh_size - offset,
- &insn->len, &insn->type,
- &insn->immediate,
- &insn->stack_ops);
- if (ret)
- goto err;
-
- /*
- * By default, "ud2" is a dead end unless otherwise
- * annotated, because GCC 7 inserts it for certain
- * divide-by-zero cases.
- */
- if (insn->type == INSN_BUG)
- insn->dead_end = true;
-
- hash_add(file->insn_hash, &insn->hash, sec_offset_hash(sec, insn->offset));
- list_add_tail(&insn->list, &file->insn_list);
- nr_insns++;
- }
-
- list_for_each_entry(func, &sec->symbol_list, list) {
- if (func->type != STT_FUNC || func->alias != func)
- continue;
-
- if (!find_insn(file, sec, func->offset)) {
- WARN("%s(): can't find starting instruction",
- func->name);
- return -1;
- }
-
- sym_for_each_insn(file, func, insn) {
- insn->func = func;
- if (insn->type == INSN_ENDBR && list_empty(&insn->call_node)) {
- if (insn->offset == insn->func->offset) {
- list_add_tail(&insn->call_node, &file->endbr_list);
- file->nr_endbr++;
- } else {
- file->nr_endbr_int++;
- }
- }
- }
- }
- }
-
- if (opts.stats)
- printf("nr_insns: %lu\n", nr_insns);
-
- return 0;
-
-err:
- free(insn);
- return ret;
-}
-
/*
* Read the pv_ops[] .data table to find the static initialized values.
*/
diff --git a/tools/objtool/decode.c b/tools/objtool/decode.c
new file mode 100644
index 000000000000..dcec3efc2afb
--- /dev/null
+++ b/tools/objtool/decode.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+#include <linux/objtool.h>
+
+#include <objtool/builtin.h>
+#include <objtool/insn.h>
+#include <objtool/warn.h>
+
+static unsigned long nr_insns;
+
+/*
+ * Call the arch-specific instruction decoder for all the instructions and add
+ * them to the global instruction list.
+ */
+int decode_instructions(struct objtool_file *file)
+{
+ struct section *sec;
+ struct symbol *func;
+ unsigned long offset;
+ struct instruction *insn;
+ int ret;
+
+ for_each_sec(file, sec) {
+
+ if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+ continue;
+
+ if (strcmp(sec->name, ".altinstr_replacement") &&
+ strcmp(sec->name, ".altinstr_aux") &&
+ strncmp(sec->name, ".discard.", 9))
+ sec->text = true;
+
+ if (!strcmp(sec->name, ".noinstr.text") ||
+ !strcmp(sec->name, ".entry.text") ||
+ !strncmp(sec->name, ".text.__x86.", 12))
+ sec->noinstr = true;
+
+ for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
+ insn = malloc(sizeof(*insn));
+ if (!insn) {
+ WARN("malloc failed");
+ return -1;
+ }
+ memset(insn, 0, sizeof(*insn));
+ INIT_LIST_HEAD(&insn->alts);
+ INIT_LIST_HEAD(&insn->stack_ops);
+ INIT_LIST_HEAD(&insn->call_node);
+
+ insn->sec = sec;
+ insn->offset = offset;
+
+ ret = arch_decode_instruction(file, sec, offset,
+ sec->sh.sh_size - offset,
+ &insn->len, &insn->type,
+ &insn->immediate,
+ &insn->stack_ops);
+ if (ret)
+ goto err;
+
+ /*
+ * By default, "ud2" is a dead end unless otherwise
+ * annotated, because GCC 7 inserts it for certain
+ * divide-by-zero cases.
+ */
+ if (insn->type == INSN_BUG)
+ insn->dead_end = true;
+
+ hash_add(file->insn_hash, &insn->hash, sec_offset_hash(sec, insn->offset));
+ list_add_tail(&insn->list, &file->insn_list);
+ nr_insns++;
+ }
+
+ list_for_each_entry(func, &sec->symbol_list, list) {
+ if (func->type != STT_FUNC || func->alias != func)
+ continue;
+
+ if (!find_insn(file, sec, func->offset)) {
+ WARN("%s(): can't find starting instruction",
+ func->name);
+ return -1;
+ }
+
+ sym_for_each_insn(file, func, insn) {
+ insn->func = func;
+ if (insn->type == INSN_ENDBR && list_empty(&insn->call_node)) {
+ if (insn->offset == insn->func->offset) {
+ list_add_tail(&insn->call_node, &file->endbr_list);
+ file->nr_endbr++;
+ } else {
+ file->nr_endbr_int++;
+ }
+ }
+ }
+ }
+ }
+
+ if (opts.stats)
+ printf("nr_insns: %lu\n", nr_insns);
+
+ return 0;
+
+err:
+ free(insn);
+ return ret;
+}
diff --git a/tools/objtool/include/objtool/insn.h b/tools/objtool/include/objtool/insn.h
index b40756a38994..b74c7f0d9076 100644
--- a/tools/objtool/include/objtool/insn.h
+++ b/tools/objtool/include/objtool/insn.h
@@ -88,6 +88,8 @@ bool insn_cfi_match(struct instruction *insn, struct cfi_state *cfi2);
bool same_function(struct instruction *insn1, struct instruction *insn2);
bool is_first_func_insn(struct objtool_file *file, struct instruction *insn);

+int decode_instructions(struct objtool_file *file);
+
#define for_each_insn(file, insn) \
list_for_each_entry(insn, &file->insn_list, list)

--
2.25.1