[PATCH 19/25] objtool: Rewrite add_ignores()

[Peter Zijlstra]

The whole add_ignores() thing was wildly weird; rewrite it according
to 'modern' ways.

Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
 tools/objtool/check.c |   51 +++++++++++++++++++-------------------------------
 tools/objtool/check.h |    1 
 2 files changed, 20 insertions(+), 32 deletions(-)

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -105,29 +105,6 @@ static struct instruction *next_insn_sam
             insn = next_insn_same_sec(file, insn))
 
 /*
- * Check if the function has been manually whitelisted with the
- * STACK_FRAME_NON_STANDARD macro, or if it should be automatically whitelisted
- * due to its use of a context switching instruction.
- */
-static bool ignore_func(struct objtool_file *file, struct symbol *func)
-{
-       struct rela *rela;
-
-       /* check for STACK_FRAME_NON_STANDARD */
-       if (file->whitelist && file->whitelist->rela)
-               list_for_each_entry(rela, &file->whitelist->rela->rela_list, 
list) {
-                       if (rela->sym->type == STT_SECTION &&
-                           rela->sym->sec == func->sec &&
-                           rela->addend == func->offset)
-                               return true;
-                       if (rela->sym->type == STT_FUNC && rela->sym == func)
-                               return true;
-               }
-
-       return false;
-}
-
-/*
  * This checks to see if the given function is a "noreturn" function.
  *
  * For global functions which are outside the scope of this object file, we
@@ -436,18 +413,31 @@ static void add_ignores(struct objtool_f
        struct instruction *insn;
        struct section *sec;
        struct symbol *func;
+       struct rela *rela;
 
-       for_each_sec(file, sec) {
-               list_for_each_entry(func, &sec->symbol_list, list) {
-                       if (func->type != STT_FUNC)
-                               continue;
+       sec = find_section_by_name(file->elf, 
".rela.discard.func_stack_frame_non_standard");
+       if (!sec)
+               return;
 
-                       if (!ignore_func(file, func))
+       list_for_each_entry(rela, &sec->rela_list, list) {
+               switch (rela->sym->type) {
+               case STT_FUNC:
+                       func = rela->sym;
+                       break;
+
+               case STT_SECTION:
+                       func = find_symbol_by_offset(rela->sym->sec, 
rela->addend);
+                       if (!func || func->type != STT_FUNC)
                                continue;
+                       break;
 
-                       func_for_each_insn_all(file, func, insn)
-                               insn->ignore = true;
+               default:
+                       WARN("unexpected relocation symbol type in %s: %d", 
sec->name, rela->sym->type);
+                       continue;
                }
+
+               func_for_each_insn_all(file, func, insn)
+                       insn->ignore = true;
        }
 }
 
@@ -2198,7 +2188,6 @@ int check(const char *_objname, bool orc
 
        INIT_LIST_HEAD(&file.insn_list);
        hash_init(file.insn_hash);
-       file.whitelist = find_section_by_name(file.elf, 
".discard.func_stack_frame_non_standard");
        file.c_file = find_section_by_name(file.elf, ".comment");
        file.ignore_unreachables = no_unreachable;
        file.hints = false;
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -60,7 +60,6 @@ struct objtool_file {
        struct elf *elf;
        struct list_head insn_list;
        DECLARE_HASHTABLE(insn_hash, 16);
-       struct section *whitelist;
        bool ignore_unreachables, c_file, hints, rodata;
 };