[RFC v2 2/6] objtool: ignore instructions

[Nadav Amit]

In certain cases there is a need to suppress objtool warnings on
specific instructions. Provide an interface to achieve this goal.

Signed-off-by: Nadav Amit <na...@vmware.com>
---
 tools/objtool/check.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 0414a0d52262..c890d714fb73 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -431,10 +431,11 @@ static int add_dead_ends(struct objtool_file *file)
 /*
  * Warnings shouldn't be reported for ignored functions.
  */
-static void add_ignores(struct objtool_file *file)
+static int add_ignores(struct objtool_file *file)
 {
        struct instruction *insn;
        struct section *sec;
+       struct rela *rela;
        struct symbol *func;
 
        for_each_sec(file, sec) {
@@ -449,6 +450,20 @@ static void add_ignores(struct objtool_file *file)
                                insn->ignore = true;
                }
        }
+
+       sec = find_section_by_name(file->elf, ".rela.discard.ignore");
+       if (!sec)
+               return 0;
+
+       list_for_each_entry(rela, &sec->rela_list, list) {
+               insn = find_insn(file, rela->sym->sec, rela->addend);
+               if (!insn) {
+                       WARN("bad .discard.ignore entry");
+                       return -1;
+               }
+               insn->ignore = true;
+       }
+       return 0;
 }
 
 /*
@@ -1237,7 +1252,9 @@ static int decode_sections(struct objtool_file *file)
        if (ret)
                return ret;
 
-       add_ignores(file);
+       ret = add_ignores(file);
+       if (ret)
+               return ret;
 
        ret = add_nospec_ignores(file);
        if (ret)
-- 
2.17.1