mirror of https://github.com/torvalds/linux.git
objtool: Extract code to validate instruction from the validate branch loop
The code to validate a branch loops through all instructions of the branch and validate each instruction. Move the code to validate an instruction to a separated function. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-9-alexandre.chartre@oracle.com
This commit is contained in:
Alexandre Chartre
Peter Zijlstra
parent
0bb080ba64
commit
a0e5bf9fd6
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@ -3654,47 +3654,27 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
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checksum_update(func, insn, &offset, sizeof(offset));
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}
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/*
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* Follow the branch starting at the given instruction, and recursively follow
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* any other branches (jumps). Meanwhile, track the frame pointer state at
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* each instruction and validate all the rules described in
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* tools/objtool/Documentation/objtool.txt.
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*/
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static int validate_branch(struct objtool_file *file, struct symbol *func,
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struct instruction *insn, struct insn_state state)
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struct instruction *insn, struct insn_state state);
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static int validate_insn(struct objtool_file *file, struct symbol *func,
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struct instruction *insn, struct insn_state *statep,
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struct instruction *prev_insn, struct instruction *next_insn,
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bool *dead_end)
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{
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struct alternative *alt;
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struct instruction *next_insn, *prev_insn = NULL;
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u8 visited;
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int ret;
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if (func && func->ignore)
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return 0;
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/*
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* Any returns before the end of this function are effectively dead
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* ends, i.e. validate_branch() has reached the end of the branch.
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*/
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*dead_end = true;
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while (1) {
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next_insn = next_insn_to_validate(file, insn);
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if (opts.checksum && func && insn->sec)
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checksum_update_insn(file, func, insn);
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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 (is_prefix_func(func))
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return 0;
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if (file->ignore_unreachables)
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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(insn)->name);
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func->warned = 1;
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return 1;
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}
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visited = VISITED_BRANCH << state.uaccess;
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visited = VISITED_BRANCH << statep->uaccess;
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if (insn->visited & VISITED_BRANCH_MASK) {
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if (!insn->hint && !insn_cfi_match(insn, &state.cfi))
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if (!insn->hint && !insn_cfi_match(insn, &statep->cfi))
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return 1;
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if (insn->visited & visited)
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@ -3703,8 +3683,8 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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nr_insns_visited++;
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}
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if (state.noinstr)
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state.instr += insn->instr;
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if (statep->noinstr)
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statep->instr += insn->instr;
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if (insn->hint) {
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if (insn->restore) {
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@ -3746,15 +3726,15 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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nr_cfi_reused++;
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}
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state.cfi = *insn->cfi;
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statep->cfi = *insn->cfi;
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} else {
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/* XXX track if we actually changed state.cfi */
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/* XXX track if we actually changed statep->cfi */
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if (prev_insn && !cficmp(prev_insn->cfi, &state.cfi)) {
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if (prev_insn && !cficmp(prev_insn->cfi, &statep->cfi)) {
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insn->cfi = prev_insn->cfi;
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nr_cfi_reused++;
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} else {
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insn->cfi = cfi_hash_find_or_add(&state.cfi);
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insn->cfi = cfi_hash_find_or_add(&statep->cfi);
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}
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}
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@ -3765,7 +3745,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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if (insn->alts) {
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for (alt = insn->alts; alt; alt = alt->next) {
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ret = validate_branch(file, func, alt->insn, state);
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ret = validate_branch(file, func, alt->insn, *statep);
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if (ret) {
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BT_INSN(insn, "(alt)");
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return ret;
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@ -3776,22 +3756,22 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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if (skip_alt_group(insn))
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return 0;
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if (handle_insn_ops(insn, next_insn, &state))
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if (handle_insn_ops(insn, next_insn, statep))
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return 1;
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switch (insn->type) {
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case INSN_RETURN:
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return validate_return(func, insn, &state);
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return validate_return(func, insn, statep);
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case INSN_CALL:
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case INSN_CALL_DYNAMIC:
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ret = validate_call(file, insn, &state);
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ret = validate_call(file, insn, statep);
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if (ret)
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return ret;
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if (opts.stackval && func && !is_special_call(insn) &&
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!has_valid_stack_frame(&state)) {
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!has_valid_stack_frame(statep)) {
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WARN_INSN(insn, "call without frame pointer save/setup");
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return 1;
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}
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@ -3801,13 +3781,13 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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case INSN_JUMP_CONDITIONAL:
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case INSN_JUMP_UNCONDITIONAL:
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if (is_sibling_call(insn)) {
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ret = validate_sibling_call(file, insn, &state);
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ret = validate_sibling_call(file, insn, statep);
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if (ret)
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return ret;
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} else if (insn->jump_dest) {
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ret = validate_branch(file, func,
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insn->jump_dest, state);
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insn->jump_dest, *statep);
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if (ret) {
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BT_INSN(insn, "(branch)");
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return ret;
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@ -3822,7 +3802,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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case INSN_JUMP_DYNAMIC:
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case INSN_JUMP_DYNAMIC_CONDITIONAL:
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if (is_sibling_call(insn)) {
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ret = validate_sibling_call(file, insn, &state);
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ret = validate_sibling_call(file, insn, statep);
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if (ret)
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return ret;
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}
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@ -3852,55 +3832,99 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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if (!opts.uaccess)
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break;
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if (state.uaccess) {
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if (statep->uaccess) {
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WARN_INSN(insn, "recursive UACCESS enable");
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return 1;
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}
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state.uaccess = true;
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statep->uaccess = true;
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break;
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case INSN_CLAC:
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if (!opts.uaccess)
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break;
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if (!state.uaccess && func) {
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if (!statep->uaccess && func) {
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WARN_INSN(insn, "redundant UACCESS disable");
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return 1;
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}
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if (func_uaccess_safe(func) && !state.uaccess_stack) {
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if (func_uaccess_safe(func) && !statep->uaccess_stack) {
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WARN_INSN(insn, "UACCESS-safe disables UACCESS");
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return 1;
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}
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state.uaccess = false;
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statep->uaccess = false;
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break;
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case INSN_STD:
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if (state.df) {
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if (statep->df) {
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WARN_INSN(insn, "recursive STD");
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return 1;
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}
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state.df = true;
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statep->df = true;
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break;
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case INSN_CLD:
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if (!state.df && func) {
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if (!statep->df && func) {
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WARN_INSN(insn, "redundant CLD");
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return 1;
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}
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state.df = false;
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statep->df = false;
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break;
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default:
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break;
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}
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if (insn->dead_end)
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*dead_end = insn->dead_end;
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return 0;
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}
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/*
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* Follow the branch starting at the given instruction, and recursively follow
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* any other branches (jumps). Meanwhile, track the frame pointer state at
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* each instruction and validate all the rules described in
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* tools/objtool/Documentation/objtool.txt.
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*/
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static int validate_branch(struct objtool_file *file, struct symbol *func,
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struct instruction *insn, struct insn_state state)
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{
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struct instruction *next_insn, *prev_insn = NULL;
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bool dead_end;
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int ret;
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if (func && func->ignore)
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return 0;
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while (1) {
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next_insn = next_insn_to_validate(file, insn);
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if (opts.checksum && func && insn->sec)
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checksum_update_insn(file, func, insn);
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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 (is_prefix_func(func))
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return 0;
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if (file->ignore_unreachables)
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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(insn)->name);
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func->warned = 1;
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return 1;
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}
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ret = validate_insn(file, func, insn, &state, prev_insn, next_insn,
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&dead_end);
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if (dead_end)
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break;
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if (!next_insn) {
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if (state.cfi.cfa.base == CFI_UNDEFINED)
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@ -3918,7 +3942,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
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insn = next_insn;
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}
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return 0;
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return ret;
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}
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static int validate_unwind_hint(struct objtool_file *file,
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