objtool: Disassemble exception table alternatives

When using the --disas option, also disassemble exception tables
(EX_TABLE).

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/20251121095340.464045-23-alexandre.chartre@oracle.com

diff --git a/tools/objtool/disas.c b/tools/objtool/disas.c
index 6083a64f6ae490ce5091a18dd326850af2b9b1a5..018aba37b996b39759c68950d9cdeaf5490e0eb6 100644 (file)
--- a/tools/objtool/disas.c
+++ b/tools/objtool/disas.c
@@ -639,6 +639,26 @@ static int disas_alt_add_insn(struct disas_alt *dalt, int index, char *insn_str,
        return 0;
 }
 
+/*
+ * Disassemble an exception table alternative.
+ */
+static int disas_alt_extable(struct disas_alt *dalt)
+{
+       struct instruction *alt_insn;
+       char *str;
+
+       alt_insn = dalt->alt->insn;
+       str = strfmt("resume at 0x%lx <%s+0x%lx>",
+                    alt_insn->offset, alt_insn->sym->name,
+                    alt_insn->offset - alt_insn->sym->offset);
+       if (!str)
+               return -1;
+
+       disas_alt_add_insn(dalt, 0, str, 0);
+
+       return 1;
+}
+
 /*
  * Disassemble an alternative and store instructions in the disas_alt
  * structure. Return the number of instructions in the alternative.
@@ -790,12 +810,16 @@ static void *disas_alt(struct disas_context *dctx,
                }
 
                /*
-                * Only group alternatives are supported at the moment.
+                * Only group alternatives and exception tables are
+                * supported at the moment.
                 */
                switch (dalt->alt->type) {
                case ALT_TYPE_INSTRUCTIONS:
                        count = disas_alt_group(dctx, dalt);
                        break;
+               case ALT_TYPE_EX_TABLE:
+                       count = disas_alt_extable(dalt);
+                       break;
                default:
                        count = 0;
                }