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Diffstat (limited to 'tools/objtool/check.c')
-rw-r--r--tools/objtool/check.c269
1 files changed, 159 insertions, 110 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 9122c20f5298..a22272c819f3 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -72,22 +72,22 @@ static struct instruction *next_insn_same_func(struct objtool_file *file,
return find_insn(file, func->cfunc->sec, func->cfunc->offset);
}
-#define func_for_each_insn_all(file, func, insn) \
+#define func_for_each_insn(file, func, insn) \
for (insn = find_insn(file, func->sec, func->offset); \
insn; \
insn = next_insn_same_func(file, insn))
-#define func_for_each_insn(file, func, insn) \
- for (insn = find_insn(file, func->sec, func->offset); \
+#define sym_for_each_insn(file, sym, insn) \
+ for (insn = find_insn(file, sym->sec, sym->offset); \
insn && &insn->list != &file->insn_list && \
- insn->sec == func->sec && \
- insn->offset < func->offset + func->len; \
+ insn->sec == sym->sec && \
+ insn->offset < sym->offset + sym->len; \
insn = list_next_entry(insn, list))
-#define func_for_each_insn_continue_reverse(file, func, insn) \
+#define sym_for_each_insn_continue_reverse(file, sym, insn) \
for (insn = list_prev_entry(insn, list); \
&insn->list != &file->insn_list && \
- insn->sec == func->sec && insn->offset >= func->offset; \
+ insn->sec == sym->sec && insn->offset >= sym->offset; \
insn = list_prev_entry(insn, list))
#define sec_for_each_insn_from(file, insn) \
@@ -97,14 +97,19 @@ static struct instruction *next_insn_same_func(struct objtool_file *file,
for (insn = next_insn_same_sec(file, insn); insn; \
insn = next_insn_same_sec(file, insn))
+static bool is_static_jump(struct instruction *insn)
+{
+ return insn->type == INSN_JUMP_CONDITIONAL ||
+ insn->type == INSN_JUMP_UNCONDITIONAL;
+}
+
static bool is_sibling_call(struct instruction *insn)
{
/* An indirect jump is either a sibling call or a jump to a table. */
if (insn->type == INSN_JUMP_DYNAMIC)
return list_empty(&insn->alts);
- if (insn->type != INSN_JUMP_CONDITIONAL &&
- insn->type != INSN_JUMP_UNCONDITIONAL)
+ if (!is_static_jump(insn))
return false;
/* add_jump_destinations() sets insn->call_dest for sibling calls. */
@@ -165,7 +170,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
if (!insn->func)
return false;
- func_for_each_insn_all(file, func, insn) {
+ func_for_each_insn(file, func, insn) {
empty = false;
if (insn->type == INSN_RETURN)
@@ -180,7 +185,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
* case, the function's dead-end status depends on whether the target
* of the sibling call returns.
*/
- func_for_each_insn_all(file, func, insn) {
+ func_for_each_insn(file, func, insn) {
if (is_sibling_call(insn)) {
struct instruction *dest = insn->jump_dest;
@@ -234,6 +239,7 @@ static int decode_instructions(struct objtool_file *file)
struct symbol *func;
unsigned long offset;
struct instruction *insn;
+ unsigned long nr_insns = 0;
int ret;
for_each_sec(file, sec) {
@@ -269,6 +275,7 @@ static int decode_instructions(struct objtool_file *file)
hash_add(file->insn_hash, &insn->hash, insn->offset);
list_add_tail(&insn->list, &file->insn_list);
+ nr_insns++;
}
list_for_each_entry(func, &sec->symbol_list, list) {
@@ -281,11 +288,14 @@ static int decode_instructions(struct objtool_file *file)
return -1;
}
- func_for_each_insn(file, func, insn)
+ sym_for_each_insn(file, func, insn)
insn->func = func;
}
}
+ if (stats)
+ printf("nr_insns: %lu\n", nr_insns);
+
return 0;
err:
@@ -415,8 +425,8 @@ static void add_ignores(struct objtool_file *file)
break;
case STT_SECTION:
- func = find_symbol_by_offset(rela->sym->sec, rela->addend);
- if (!func || func->type != STT_FUNC)
+ func = find_func_by_offset(rela->sym->sec, rela->addend);
+ if (!func)
continue;
break;
@@ -425,7 +435,7 @@ static void add_ignores(struct objtool_file *file)
continue;
}
- func_for_each_insn_all(file, func, insn)
+ func_for_each_insn(file, func, insn)
insn->ignore = true;
}
}
@@ -500,6 +510,7 @@ static const char *uaccess_safe_builtin[] = {
"__sanitizer_cov_trace_cmp2",
"__sanitizer_cov_trace_cmp4",
"__sanitizer_cov_trace_cmp8",
+ "__sanitizer_cov_trace_switch",
/* UBSAN */
"ubsan_type_mismatch_common",
"__ubsan_handle_type_mismatch",
@@ -575,15 +586,14 @@ static int add_jump_destinations(struct objtool_file *file)
unsigned long dest_off;
for_each_insn(file, insn) {
- if (insn->type != INSN_JUMP_CONDITIONAL &&
- insn->type != INSN_JUMP_UNCONDITIONAL)
+ if (!is_static_jump(insn))
continue;
if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET)
continue;
- rela = find_rela_by_dest_range(insn->sec, insn->offset,
- insn->len);
+ rela = find_rela_by_dest_range(file->elf, insn->sec,
+ insn->offset, insn->len);
if (!rela) {
dest_sec = insn->sec;
dest_off = insn->offset + insn->len + insn->immediate;
@@ -679,14 +689,18 @@ static int add_call_destinations(struct objtool_file *file)
if (insn->type != INSN_CALL)
continue;
- rela = find_rela_by_dest_range(insn->sec, insn->offset,
- insn->len);
+ rela = find_rela_by_dest_range(file->elf, insn->sec,
+ insn->offset, insn->len);
if (!rela) {
dest_off = insn->offset + insn->len + insn->immediate;
- insn->call_dest = find_symbol_by_offset(insn->sec,
- dest_off);
+ insn->call_dest = find_func_by_offset(insn->sec, dest_off);
+ if (!insn->call_dest)
+ insn->call_dest = find_symbol_by_offset(insn->sec, dest_off);
- if (!insn->call_dest && !insn->ignore) {
+ if (insn->ignore)
+ continue;
+
+ if (!insn->call_dest) {
WARN_FUNC("unsupported intra-function call",
insn->sec, insn->offset);
if (retpoline)
@@ -694,11 +708,16 @@ static int add_call_destinations(struct objtool_file *file)
return -1;
}
+ if (insn->func && insn->call_dest->type != STT_FUNC) {
+ WARN_FUNC("unsupported call to non-function",
+ insn->sec, insn->offset);
+ return -1;
+ }
+
} else if (rela->sym->type == STT_SECTION) {
- insn->call_dest = find_symbol_by_offset(rela->sym->sec,
- rela->addend+4);
- if (!insn->call_dest ||
- insn->call_dest->type != STT_FUNC) {
+ insn->call_dest = find_func_by_offset(rela->sym->sec,
+ rela->addend+4);
+ if (!insn->call_dest) {
WARN_FUNC("can't find call dest symbol at %s+0x%x",
insn->sec, insn->offset,
rela->sym->sec->name,
@@ -786,8 +805,28 @@ static int handle_group_alt(struct objtool_file *file,
insn->ignore = orig_insn->ignore_alts;
insn->func = orig_insn->func;
- if (insn->type != INSN_JUMP_CONDITIONAL &&
- insn->type != INSN_JUMP_UNCONDITIONAL)
+ /*
+ * Since alternative replacement code is copy/pasted by the
+ * kernel after applying relocations, generally such code can't
+ * have relative-address relocation references to outside the
+ * .altinstr_replacement section, unless the arch's
+ * alternatives code can adjust the relative offsets
+ * accordingly.
+ *
+ * The x86 alternatives code adjusts the offsets only when it
+ * encounters a branch instruction at the very beginning of the
+ * replacement group.
+ */
+ if ((insn->offset != special_alt->new_off ||
+ (insn->type != INSN_CALL && !is_static_jump(insn))) &&
+ find_rela_by_dest_range(file->elf, insn->sec, insn->offset, insn->len)) {
+
+ WARN_FUNC("unsupported relocation in alternatives section",
+ insn->sec, insn->offset);
+ return -1;
+ }
+
+ if (!is_static_jump(insn))
continue;
if (!insn->immediate)
@@ -1023,7 +1062,7 @@ static struct rela *find_jump_table(struct objtool_file *file,
struct instruction *insn)
{
struct rela *text_rela, *table_rela;
- struct instruction *orig_insn = insn;
+ struct instruction *dest_insn, *orig_insn = insn;
struct section *table_sec;
unsigned long table_offset;
@@ -1050,8 +1089,8 @@ static struct rela *find_jump_table(struct objtool_file *file,
break;
/* look for a relocation which references .rodata */
- text_rela = find_rela_by_dest_range(insn->sec, insn->offset,
- insn->len);
+ text_rela = find_rela_by_dest_range(file->elf, insn->sec,
+ insn->offset, insn->len);
if (!text_rela || text_rela->sym->type != STT_SECTION ||
!text_rela->sym->sec->rodata)
continue;
@@ -1075,10 +1114,17 @@ static struct rela *find_jump_table(struct objtool_file *file,
strcmp(table_sec->name, C_JUMP_TABLE_SECTION))
continue;
- /* Each table entry has a rela associated with it. */
- table_rela = find_rela_by_dest(table_sec, table_offset);
+ /*
+ * Each table entry has a rela associated with it. The rela
+ * should reference text in the same function as the original
+ * instruction.
+ */
+ table_rela = find_rela_by_dest(file->elf, table_sec, table_offset);
if (!table_rela)
continue;
+ dest_insn = find_insn(file, table_rela->sym->sec, table_rela->addend);
+ if (!dest_insn || !dest_insn->func || dest_insn->func->pfunc != func)
+ continue;
/*
* Use of RIP-relative switch jumps is quite rare, and
@@ -1104,7 +1150,7 @@ static void mark_func_jump_tables(struct objtool_file *file,
struct instruction *insn, *last = NULL;
struct rela *rela;
- func_for_each_insn_all(file, func, insn) {
+ func_for_each_insn(file, func, insn) {
if (!last)
last = insn;
@@ -1139,7 +1185,7 @@ static int add_func_jump_tables(struct objtool_file *file,
struct instruction *insn;
int ret;
- func_for_each_insn_all(file, func, insn) {
+ func_for_each_insn(file, func, insn) {
if (!insn->jump_table)
continue;
@@ -1209,7 +1255,7 @@ static int read_unwind_hints(struct objtool_file *file)
for (i = 0; i < sec->len / sizeof(struct unwind_hint); i++) {
hint = (struct unwind_hint *)sec->data->d_buf + i;
- rela = find_rela_by_dest(sec, i * sizeof(*hint));
+ rela = find_rela_by_dest(file->elf, sec, i * sizeof(*hint));
if (!rela) {
WARN("can't find rela for unwind_hints[%d]", i);
return -1;
@@ -1957,6 +2003,41 @@ static int validate_sibling_call(struct instruction *insn, struct insn_state *st
return validate_call(insn, state);
}
+static int validate_return(struct symbol *func, struct instruction *insn, struct insn_state *state)
+{
+ if (state->uaccess && !func_uaccess_safe(func)) {
+ WARN_FUNC("return with UACCESS enabled",
+ insn->sec, insn->offset);
+ return 1;
+ }
+
+ if (!state->uaccess && func_uaccess_safe(func)) {
+ WARN_FUNC("return with UACCESS disabled from a UACCESS-safe function",
+ insn->sec, insn->offset);
+ return 1;
+ }
+
+ if (state->df) {
+ WARN_FUNC("return with DF set",
+ insn->sec, insn->offset);
+ return 1;
+ }
+
+ if (func && has_modified_stack_frame(state)) {
+ WARN_FUNC("return with modified stack frame",
+ insn->sec, insn->offset);
+ return 1;
+ }
+
+ if (state->bp_scratch) {
+ WARN("%s uses BP as a scratch register",
+ func->name);
+ return 1;
+ }
+
+ return 0;
+}
+
/*
* Follow the branch starting at the given instruction, and recursively follow
* any other branches (jumps). Meanwhile, track the frame pointer state at
@@ -2011,7 +2092,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
i = insn;
save_insn = NULL;
- func_for_each_insn_continue_reverse(file, func, i) {
+ sym_for_each_insn_continue_reverse(file, func, i) {
if (i->save) {
save_insn = i;
break;
@@ -2072,34 +2153,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
switch (insn->type) {
case INSN_RETURN:
- if (state.uaccess && !func_uaccess_safe(func)) {
- WARN_FUNC("return with UACCESS enabled", sec, insn->offset);
- return 1;
- }
-
- if (!state.uaccess && func_uaccess_safe(func)) {
- WARN_FUNC("return with UACCESS disabled from a UACCESS-safe function", sec, insn->offset);
- return 1;
- }
-
- if (state.df) {
- WARN_FUNC("return with DF set", sec, insn->offset);
- return 1;
- }
-
- if (func && has_modified_stack_frame(&state)) {
- WARN_FUNC("return with modified stack frame",
- sec, insn->offset);
- return 1;
- }
-
- if (state.bp_scratch) {
- WARN("%s uses BP as a scratch register",
- func->name);
- return 1;
- }
-
- return 0;
+ return validate_return(func, insn, &state);
case INSN_CALL:
case INSN_CALL_DYNAMIC:
@@ -2364,9 +2418,8 @@ static bool ignore_unreachable_insn(struct instruction *insn)
return false;
}
-static int validate_functions(struct objtool_file *file)
+static int validate_section(struct objtool_file *file, struct section *sec)
{
- struct section *sec;
struct symbol *func;
struct instruction *insn;
struct insn_state state;
@@ -2379,36 +2432,45 @@ static int validate_functions(struct objtool_file *file)
CFI_NUM_REGS * sizeof(struct cfi_reg));
state.stack_size = initial_func_cfi.cfa.offset;
- for_each_sec(file, sec) {
- list_for_each_entry(func, &sec->symbol_list, list) {
- if (func->type != STT_FUNC)
- continue;
+ list_for_each_entry(func, &sec->symbol_list, list) {
+ if (func->type != STT_FUNC)
+ continue;
- if (!func->len) {
- WARN("%s() is missing an ELF size annotation",
- func->name);
- warnings++;
- }
+ if (!func->len) {
+ WARN("%s() is missing an ELF size annotation",
+ func->name);
+ warnings++;
+ }
- if (func->pfunc != func || func->alias != func)
- continue;
+ if (func->pfunc != func || func->alias != func)
+ continue;
- insn = find_insn(file, sec, func->offset);
- if (!insn || insn->ignore || insn->visited)
- continue;
+ insn = find_insn(file, sec, func->offset);
+ if (!insn || insn->ignore || insn->visited)
+ continue;
- state.uaccess = func->uaccess_safe;
+ state.uaccess = func->uaccess_safe;
- ret = validate_branch(file, func, insn, state);
- if (ret && backtrace)
- BT_FUNC("<=== (func)", insn);
- warnings += ret;
- }
+ ret = validate_branch(file, func, insn, state);
+ if (ret && backtrace)
+ BT_FUNC("<=== (func)", insn);
+ warnings += ret;
}
return warnings;
}
+static int validate_functions(struct objtool_file *file)
+{
+ struct section *sec;
+ int warnings = 0;
+
+ for_each_sec(file, sec)
+ warnings += validate_section(file, sec);
+
+ return warnings;
+}
+
static int validate_reachable_instructions(struct objtool_file *file)
{
struct instruction *insn;
@@ -2427,23 +2489,6 @@ static int validate_reachable_instructions(struct objtool_file *file)
return 0;
}
-static void cleanup(struct objtool_file *file)
-{
- struct instruction *insn, *tmpinsn;
- struct alternative *alt, *tmpalt;
-
- list_for_each_entry_safe(insn, tmpinsn, &file->insn_list, list) {
- list_for_each_entry_safe(alt, tmpalt, &insn->alts, list) {
- list_del(&alt->list);
- free(alt);
- }
- list_del(&insn->list);
- hash_del(&insn->hash);
- free(insn);
- }
- elf_close(file->elf);
-}
-
static struct objtool_file file;
int check(const char *_objname, bool orc)
@@ -2511,10 +2556,14 @@ int check(const char *_objname, bool orc)
}
out:
- cleanup(&file);
+ if (ret < 0) {
+ /*
+ * Fatal error. The binary is corrupt or otherwise broken in
+ * some way, or objtool itself is broken. Fail the kernel
+ * build.
+ */
+ return ret;
+ }
- /* ignore warnings for now until we get all the code cleaned up */
- if (ret || warnings)
- return 0;
return 0;
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-26 21:16:10 +0300