objtool: Support stack layout changes in alternatives

[sfrench/cifs-2.6.git] / tools / objtool / orc_gen.c

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 38e1a8dbfff09530c6a7e63ace6d8288d5e1d300..738aa5021bc4b6d6fbd55d7edb7549e2bb4134c6 100644 (file)
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -144,6 +144,13 @@ static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc,
        return 0;
 }
 
+static unsigned long alt_group_len(struct alt_group *alt_group)
+{
+       return alt_group->last_insn->offset +
+              alt_group->last_insn->len -
+              alt_group->first_insn->offset;
+}
+
 int orc_create(struct objtool_file *file)
 {
        struct section *sec, *ip_rsec, *orc_sec;
@@ -168,15 +175,48 @@ int orc_create(struct objtool_file *file)
                        continue;
 
                sec_for_each_insn(file, sec, insn) {
-                       if (init_orc_entry(&orc, &insn->cfi))
-                               return -1;
-                       if (!memcmp(&prev_orc, &orc, sizeof(orc)))
+                       struct alt_group *alt_group = insn->alt_group;
+                       int i;
+
+                       if (!alt_group) {
+                               if (init_orc_entry(&orc, &insn->cfi))
+                                       return -1;
+                               if (!memcmp(&prev_orc, &orc, sizeof(orc)))
+                                       continue;
+                               if (orc_list_add(&orc_list, &orc, sec,
+                                                insn->offset))
+                                       return -1;
+                               nr++;
+                               prev_orc = orc;
+                               empty = false;
                                continue;
-                       if (orc_list_add(&orc_list, &orc, sec, insn->offset))
-                               return -1;
-                       nr++;
-                       prev_orc = orc;
-                       empty = false;
+                       }
+
+                       /*
+                        * Alternatives can have different stack layout
+                        * possibilities (but they shouldn't conflict).
+                        * Instead of traversing the instructions, use the
+                        * alt_group's flattened byte-offset-addressed CFI
+                        * array.
+                        */
+                       for (i = 0; i < alt_group_len(alt_group); i++) {
+                               struct cfi_state *cfi = alt_group->cfi[i];
+                               if (!cfi)
+                                       continue;
+                               if (init_orc_entry(&orc, cfi))
+                                       return -1;
+                               if (!memcmp(&prev_orc, &orc, sizeof(orc)))
+                                       continue;
+                               if (orc_list_add(&orc_list, &orc, insn->sec,
+                                                insn->offset + i))
+                                       return -1;
+                               nr++;
+                               prev_orc = orc;
+                               empty = false;
+                       }
+
+                       /* Skip to the end of the alt_group */
+                       insn = alt_group->last_insn;
                }
 
                /* Add a section terminator */