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https://mirrors.bfsu.edu.cn/git/linux.git
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objtool: Rework instruction -> symbol mapping
Currently insn->func contains a instruction -> symbol link for STT_FUNC symbols. A NULL value is assumed to mean STT_NOTYPE. However, there are also instructions not covered by any symbol at all. This can happen due to __weak symbols for example. Since the current scheme cannot differentiate between no symbol and STT_NOTYPE symbol, change things around. Make insn->sym point to any symbol type such that !insn->sym means no symbol and add a helper insn_func() that check the sym->type to retain the old functionality. This then prepares the way to add code that depends on the distinction between STT_NOTYPE and no symbol at all. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This commit is contained in:
Peter Zijlstra
parent
08ef8c4011
commit
dbcdbdfdf1
@ -62,12 +62,12 @@ static struct instruction *next_insn_same_func(struct objtool_file *file,
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struct instruction *insn)
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{
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struct instruction *next = list_next_entry(insn, list);
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struct symbol *func = insn->func;
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struct symbol *func = insn_func(insn);
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if (!func)
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return NULL;
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if (&next->list != &file->insn_list && next->func == func)
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if (&next->list != &file->insn_list && insn_func(next) == func)
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return next;
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/* Check if we're already in the subfunction: */
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@ -83,7 +83,7 @@ static struct instruction *prev_insn_same_sym(struct objtool_file *file,
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{
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struct instruction *prev = list_prev_entry(insn, list);
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if (&prev->list != &file->insn_list && prev->func == insn->func)
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if (&prev->list != &file->insn_list && insn_func(prev) == insn_func(insn))
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return prev;
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return NULL;
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@ -133,7 +133,7 @@ static bool is_sibling_call(struct instruction *insn)
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* sibling call detection consistency between vmlinux.o and individual
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* objects.
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*/
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if (!insn->func)
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if (!insn_func(insn))
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return false;
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/* An indirect jump is either a sibling call or a jump to a table. */
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@ -207,7 +207,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
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return false;
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insn = find_insn(file, func->sec, func->offset);
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if (!insn->func)
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if (!insn_func(insn))
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return false;
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func_for_each_insn(file, func, insn) {
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@ -243,7 +243,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
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return false;
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}
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return __dead_end_function(file, dest->func, recursion+1);
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return __dead_end_function(file, insn_func(dest), recursion+1);
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}
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}
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@ -427,7 +427,10 @@ static int decode_instructions(struct objtool_file *file)
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}
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list_for_each_entry(func, &sec->symbol_list, list) {
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if (func->type != STT_FUNC || func->alias != func)
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if (func->type != STT_NOTYPE && func->type != STT_FUNC)
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continue;
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if (func->return_thunk || func->alias != func)
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continue;
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if (!find_insn(file, sec, func->offset)) {
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@ -437,9 +440,11 @@ static int decode_instructions(struct objtool_file *file)
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}
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sym_for_each_insn(file, func, insn) {
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insn->func = func;
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if (insn->type == INSN_ENDBR && list_empty(&insn->call_node)) {
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if (insn->offset == insn->func->offset) {
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insn->sym = func;
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if (func->type == STT_FUNC &&
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insn->type == INSN_ENDBR &&
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list_empty(&insn->call_node)) {
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if (insn->offset == func->offset) {
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list_add_tail(&insn->call_node, &file->endbr_list);
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file->nr_endbr++;
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} else {
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@ -1397,19 +1402,19 @@ static void add_return_call(struct objtool_file *file, struct instruction *insn,
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static bool same_function(struct instruction *insn1, struct instruction *insn2)
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{
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return insn1->func->pfunc == insn2->func->pfunc;
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return insn_func(insn1)->pfunc == insn_func(insn2)->pfunc;
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}
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static bool is_first_func_insn(struct objtool_file *file, struct instruction *insn)
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{
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if (insn->offset == insn->func->offset)
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if (insn->offset == insn_func(insn)->offset)
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return true;
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if (opts.ibt) {
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struct instruction *prev = prev_insn_same_sym(file, insn);
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if (prev && prev->type == INSN_ENDBR &&
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insn->offset == insn->func->offset + prev->len)
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insn->offset == insn_func(insn)->offset + prev->len)
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return true;
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}
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@ -1450,7 +1455,7 @@ static int add_jump_destinations(struct objtool_file *file)
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} else if (reloc->sym->return_thunk) {
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add_return_call(file, insn, true);
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continue;
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} else if (insn->func) {
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} else if (insn_func(insn)) {
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/*
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* External sibling call or internal sibling call with
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* STT_FUNC reloc.
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@ -1492,8 +1497,8 @@ static int add_jump_destinations(struct objtool_file *file)
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/*
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* Cross-function jump.
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*/
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if (insn->func && jump_dest->func &&
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insn->func != jump_dest->func) {
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if (insn_func(insn) && insn_func(jump_dest) &&
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insn_func(insn) != insn_func(jump_dest)) {
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/*
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* For GCC 8+, create parent/child links for any cold
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@ -1510,10 +1515,10 @@ static int add_jump_destinations(struct objtool_file *file)
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* case where the parent function's only reference to a
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* subfunction is through a jump table.
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*/
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if (!strstr(insn->func->name, ".cold") &&
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strstr(jump_dest->func->name, ".cold")) {
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insn->func->cfunc = jump_dest->func;
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jump_dest->func->pfunc = insn->func;
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if (!strstr(insn_func(insn)->name, ".cold") &&
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strstr(insn_func(jump_dest)->name, ".cold")) {
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insn_func(insn)->cfunc = insn_func(jump_dest);
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insn_func(jump_dest)->pfunc = insn_func(insn);
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} else if (!same_function(insn, jump_dest) &&
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is_first_func_insn(file, jump_dest)) {
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@ -1521,7 +1526,7 @@ static int add_jump_destinations(struct objtool_file *file)
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* Internal sibling call without reloc or with
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* STT_SECTION reloc.
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*/
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add_call_dest(file, insn, jump_dest->func, true);
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add_call_dest(file, insn, insn_func(jump_dest), true);
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continue;
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}
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}
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@ -1572,7 +1577,7 @@ static int add_call_destinations(struct objtool_file *file)
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return -1;
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}
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if (insn->func && insn->call_dest->type != STT_FUNC) {
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if (insn_func(insn) && insn->call_dest->type != STT_FUNC) {
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WARN_FUNC("unsupported call to non-function",
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insn->sec, insn->offset);
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return -1;
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@ -1668,7 +1673,7 @@ static int handle_group_alt(struct objtool_file *file,
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nop->offset = special_alt->new_off + special_alt->new_len;
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nop->len = special_alt->orig_len - special_alt->new_len;
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nop->type = INSN_NOP;
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nop->func = orig_insn->func;
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nop->sym = orig_insn->sym;
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nop->alt_group = new_alt_group;
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nop->ignore = orig_insn->ignore_alts;
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}
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@ -1688,7 +1693,7 @@ static int handle_group_alt(struct objtool_file *file,
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last_new_insn = insn;
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insn->ignore = orig_insn->ignore_alts;
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insn->func = orig_insn->func;
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insn->sym = orig_insn->sym;
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insn->alt_group = new_alt_group;
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/*
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@ -1882,7 +1887,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
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struct reloc *reloc = table;
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struct instruction *dest_insn;
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struct alternative *alt;
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struct symbol *pfunc = insn->func->pfunc;
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struct symbol *pfunc = insn_func(insn)->pfunc;
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unsigned int prev_offset = 0;
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/*
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@ -1909,7 +1914,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
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break;
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/* Make sure the destination is in the same function: */
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if (!dest_insn->func || dest_insn->func->pfunc != pfunc)
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if (!insn_func(dest_insn) || insn_func(dest_insn)->pfunc != pfunc)
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break;
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alt = malloc(sizeof(*alt));
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@ -1949,7 +1954,7 @@ static struct reloc *find_jump_table(struct objtool_file *file,
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* it.
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*/
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for (;
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insn && insn->func && insn->func->pfunc == func;
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insn && insn_func(insn) && insn_func(insn)->pfunc == func;
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insn = insn->first_jump_src ?: prev_insn_same_sym(file, insn)) {
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if (insn != orig_insn && insn->type == INSN_JUMP_DYNAMIC)
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@ -1966,7 +1971,7 @@ static struct reloc *find_jump_table(struct objtool_file *file,
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if (!table_reloc)
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continue;
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dest_insn = find_insn(file, table_reloc->sym->sec, table_reloc->addend);
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if (!dest_insn || !dest_insn->func || dest_insn->func->pfunc != func)
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if (!dest_insn || !insn_func(dest_insn) || insn_func(dest_insn)->pfunc != func)
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continue;
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return table_reloc;
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@ -2415,6 +2420,13 @@ static int decode_sections(struct objtool_file *file)
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if (ret)
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return ret;
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/*
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* Must be before add_{jump_call}_destination.
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*/
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ret = classify_symbols(file);
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if (ret)
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return ret;
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ret = decode_instructions(file);
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if (ret)
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return ret;
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@ -2433,13 +2445,6 @@ static int decode_sections(struct objtool_file *file)
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if (ret)
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return ret;
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/*
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* Must be before add_{jump_call}_destination.
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*/
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ret = classify_symbols(file);
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if (ret)
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return ret;
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/*
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* Must be before add_jump_destinations(), which depends on 'func'
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* being set for alternatives, to enable proper sibling call detection.
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@ -2648,7 +2653,7 @@ static int update_cfi_state(struct instruction *insn,
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/* stack operations don't make sense with an undefined CFA */
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if (cfa->base == CFI_UNDEFINED) {
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if (insn->func) {
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if (insn_func(insn)) {
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WARN_FUNC("undefined stack state", insn->sec, insn->offset);
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return -1;
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}
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@ -2994,7 +2999,7 @@ static int update_cfi_state(struct instruction *insn,
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}
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/* detect when asm code uses rbp as a scratch register */
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if (opts.stackval && insn->func && op->src.reg == CFI_BP &&
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if (opts.stackval && insn_func(insn) && op->src.reg == CFI_BP &&
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cfa->base != CFI_BP)
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cfi->bp_scratch = true;
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break;
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@ -3390,13 +3395,13 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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while (1) {
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next_insn = next_insn_to_validate(file, insn);
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if (func && insn->func && func != insn->func->pfunc) {
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if (func && insn_func(insn) && func != insn_func(insn)->pfunc) {
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/* Ignore KCFI type preambles, which always fall through */
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if (!strncmp(func->name, "__cfi_", 6))
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return 0;
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WARN("%s() falls through to next function %s()",
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func->name, insn->func->name);
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func->name, insn_func(insn)->name);
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return 1;
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}
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@ -3638,7 +3643,7 @@ static int validate_unwind_hints(struct objtool_file *file, struct section *sec)
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while (&insn->list != &file->insn_list && (!sec || insn->sec == sec)) {
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if (insn->hint && !insn->visited && !insn->ignore) {
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ret = validate_branch(file, insn->func, insn, state);
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ret = validate_branch(file, insn_func(insn), insn, state);
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if (ret && opts.backtrace)
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BT_FUNC("<=== (hint)", insn);
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warnings += ret;
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@ -3861,7 +3866,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
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* In this case we'll find a piece of code (whole function) that is not
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* covered by a !section symbol. Ignore them.
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*/
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if (opts.link && !insn->func) {
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if (opts.link && !insn_func(insn)) {
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int size = find_symbol_hole_containing(insn->sec, insn->offset);
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unsigned long end = insn->offset + size;
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@ -3885,10 +3890,10 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
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/*
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* If this hole jumps to a .cold function, mark it ignore too.
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*/
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if (insn->jump_dest && insn->jump_dest->func &&
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strstr(insn->jump_dest->func->name, ".cold")) {
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if (insn->jump_dest && insn_func(insn->jump_dest) &&
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strstr(insn_func(insn->jump_dest)->name, ".cold")) {
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struct instruction *dest = insn->jump_dest;
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func_for_each_insn(file, dest->func, dest)
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func_for_each_insn(file, insn_func(dest), dest)
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dest->ignore = true;
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}
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}
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@ -3896,10 +3901,10 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
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return false;
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}
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if (!insn->func)
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if (!insn_func(insn))
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return false;
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if (insn->func->static_call_tramp)
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if (insn_func(insn)->static_call_tramp)
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return true;
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/*
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@ -3930,7 +3935,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
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if (insn->type == INSN_JUMP_UNCONDITIONAL) {
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if (insn->jump_dest &&
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insn->jump_dest->func == insn->func) {
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insn_func(insn->jump_dest) == insn_func(insn)) {
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insn = insn->jump_dest;
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continue;
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}
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@ -3938,7 +3943,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
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break;
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}
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if (insn->offset + insn->len >= insn->func->offset + insn->func->len)
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if (insn->offset + insn->len >= insn_func(insn)->offset + insn_func(insn)->len)
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break;
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insn = list_next_entry(insn, list);
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@ -3967,7 +3972,7 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
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state->uaccess = sym->uaccess_safe;
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ret = validate_branch(file, insn->func, insn, *state);
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ret = validate_branch(file, insn_func(insn), insn, *state);
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if (ret && opts.backtrace)
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BT_FUNC("<=== (sym)", insn);
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return ret;
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@ -4104,7 +4109,7 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn
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continue;
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}
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if (dest->func && dest->func == insn->func) {
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if (insn_func(dest) && insn_func(dest) == insn_func(insn)) {
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/*
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* Anything from->to self is either _THIS_IP_ or
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* IRET-to-self.
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@ -67,11 +67,21 @@ struct instruction {
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struct reloc *jump_table;
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struct reloc *reloc;
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struct list_head alts;
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struct symbol *func;
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struct symbol *sym;
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struct list_head stack_ops;
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struct cfi_state *cfi;
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};
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static inline struct symbol *insn_func(struct instruction *insn)
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{
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struct symbol *sym = insn->sym;
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if (sym && sym->type != STT_FUNC)
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sym = NULL;
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return sym;
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}
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#define VISITED_BRANCH 0x01
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#define VISITED_BRANCH_UACCESS 0x02
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#define VISITED_BRANCH_MASK 0x03
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