objtool: Ignore entire functions rather than instructions

STACK_FRAME_NON_STANDARD applies to functions.  Use a function-specific
ignore attribute in preparation for getting rid of insn->ignore.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/4af13376567f83331a9372ae2bb25e11a3d0f055.1742852846.git.jpoimboe@kernel.org

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index dae17ed4a5d74a432c88e2687c0e41160536b149..f4650205854d30a58f3c5216c147b42b96ec08e2 100644 (file)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -981,7 +981,6 @@ static int create_direct_call_sections(struct objtool_file *file)
  */
 static void add_ignores(struct objtool_file *file)
 {
-       struct instruction *insn;
        struct section *rsec;
        struct symbol *func;
        struct reloc *reloc;
@@ -1008,8 +1007,7 @@ static void add_ignores(struct objtool_file *file)
                        continue;
                }
 
-               func_for_each_insn(file, func, insn)
-                       insn->ignore = true;
+               func->ignore = true;
        }
 }
 
@@ -1612,6 +1610,7 @@ static int add_call_destinations(struct objtool_file *file)
        struct reloc *reloc;
 
        for_each_insn(file, insn) {
+               struct symbol *func = insn_func(insn);
                if (insn->type != INSN_CALL)
                        continue;
 
@@ -1622,7 +1621,7 @@ static int add_call_destinations(struct objtool_file *file)
 
                        add_call_dest(file, insn, dest, false);
 
-                       if (insn->ignore)
+                       if (func && func->ignore)
                                continue;
 
                        if (!insn_call_dest(insn)) {
@@ -1630,7 +1629,7 @@ static int add_call_destinations(struct objtool_file *file)
                                return -1;
                        }
 
-                       if (insn_func(insn) && insn_call_dest(insn)->type != STT_FUNC) {
+                       if (func && insn_call_dest(insn)->type != STT_FUNC) {
                                WARN_INSN(insn, "unsupported call to non-function");
                                return -1;
                        }
@@ -3470,6 +3469,9 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
        u8 visited;
        int ret;
 
+       if (func && func->ignore)
+               return 0;
+
        sec = insn->sec;
 
        while (1) {
@@ -3715,7 +3717,7 @@ static int validate_unwind_hint(struct objtool_file *file,
                                  struct instruction *insn,
                                  struct insn_state *state)
 {
-       if (insn->hint && !insn->visited && !insn->ignore) {
+       if (insn->hint && !insn->visited) {
                int ret = validate_branch(file, insn_func(insn), insn, *state);
                if (ret)
                        BT_INSN(insn, "<=== (hint)");
@@ -3929,10 +3931,11 @@ static bool is_ubsan_insn(struct instruction *insn)
 
 static bool ignore_unreachable_insn(struct objtool_file *file, struct instruction *insn)
 {
-       int i;
+       struct symbol *func = insn_func(insn);
        struct instruction *prev_insn;
+       int i;
 
-       if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP)
+       if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP || (func && func->ignore))
                return true;
 
        /*
@@ -3951,7 +3954,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
         * In this case we'll find a piece of code (whole function) that is not
         * covered by a !section symbol. Ignore them.
         */
-       if (opts.link && !insn_func(insn)) {
+       if (opts.link && !func) {
                int size = find_symbol_hole_containing(insn->sec, insn->offset);
                unsigned long end = insn->offset + size;
 
@@ -3977,19 +3980,17 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
                         */
                        if (insn->jump_dest && insn_func(insn->jump_dest) &&
                            strstr(insn_func(insn->jump_dest)->name, ".cold")) {
-                               struct instruction *dest = insn->jump_dest;
-                               func_for_each_insn(file, insn_func(dest), dest)
-                                       dest->ignore = true;
+                               insn_func(insn->jump_dest)->ignore = true;
                        }
                }
 
                return false;
        }
 
-       if (!insn_func(insn))
+       if (!func)
                return false;
 
-       if (insn_func(insn)->static_call_tramp)
+       if (func->static_call_tramp)
                return true;
 
        /*
@@ -4020,7 +4021,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
 
                if (insn->type == INSN_JUMP_UNCONDITIONAL) {
                        if (insn->jump_dest &&
-                           insn_func(insn->jump_dest) == insn_func(insn)) {
+                           insn_func(insn->jump_dest) == func) {
                                insn = insn->jump_dest;
                                continue;
                        }
@@ -4028,7 +4029,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
                        break;
                }
 
-               if (insn->offset + insn->len >= insn_func(insn)->offset + insn_func(insn)->len)
+               if (insn->offset + insn->len >= func->offset + func->len)
                        break;
 
                insn = next_insn_same_sec(file, insn);
@@ -4120,7 +4121,7 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
                return 0;
 
        insn = find_insn(file, sec, sym->offset);
-       if (!insn || insn->ignore || insn->visited)
+       if (!insn || insn->visited)
                return 0;
 
        state->uaccess = sym->uaccess_safe;

diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 4edc957a6f6b88a17180630ce58ba48e972f8eea..eba04392c6fd4aa3aca56dce50426d2982edc9ab 100644 (file)
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -68,6 +68,7 @@ struct symbol {
        u8 embedded_insn     : 1;
        u8 local_label       : 1;
        u8 frame_pointer     : 1;
+       u8 ignore            : 1;
        u8 warnings          : 2;
        struct list_head pv_target;
        struct reloc *relocs;