1 files changed, 48 insertions, 42 deletions

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f40d46e24bcc..b00b1896547e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -138,6 +138,7 @@ static int __dead_end_function(struct objtool_file *file, struct symbol *func,
                 "__reiserfs_panic",
                 "lbug_with_loc",
                 "fortify_panic",
+                "usercopy_abort",
         };
 
         if (func->bind == STB_WEAK)
@@ -543,18 +544,14 @@ static int add_call_destinations(struct objtool_file *file)
                         dest_off = insn->offset + insn->len + insn->immediate;
                         insn->call_dest = find_symbol_by_offset(insn->sec,
                                                                 dest_off);
-                        /*
-                         * FIXME: Thanks to retpolines, it's now considered
-                         * normal for a function to call within itself.  So
-                         * disable this warning for now.
-                         */
-#if 0
-                        if (!insn->call_dest) {
-                                WARN_FUNC("can't find call dest symbol at offset 0x%lx",
-                                          insn->sec, insn->offset, dest_off);
+
+                        if (!insn->call_dest && !insn->ignore) {
+                                WARN_FUNC("unsupported intra-function call",
+                                          insn->sec, insn->offset);
+                                WARN("If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE.");
                                 return -1;
                         }
-#endif
+
                 } else if (rela->sym->type == STT_SECTION) {
                         insn->call_dest = find_symbol_by_offset(rela->sym->sec,
                                                                 rela->addend+4);
@@ -598,7 +595,7 @@ static int handle_group_alt(struct objtool_file *file,
                             struct instruction *orig_insn,
                             struct instruction **new_insn)
 {
-        struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump;
+        struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump = NULL;
         unsigned long dest_off;
 
         last_orig_insn = NULL;
@@ -614,28 +611,30 @@ static int handle_group_alt(struct objtool_file *file,
                 last_orig_insn = insn;
         }
 
-        if (!next_insn_same_sec(file, last_orig_insn)) {
-                WARN("%s: don't know how to handle alternatives at end of section",
-                     special_alt->orig_sec->name);
-                return -1;
-        }
-
-        fake_jump = malloc(sizeof(*fake_jump));
-        if (!fake_jump) {
-                WARN("malloc failed");
-                return -1;
+        if (next_insn_same_sec(file, last_orig_insn)) {
+                fake_jump = malloc(sizeof(*fake_jump));
+                if (!fake_jump) {
+                        WARN("malloc failed");
+                        return -1;
+                }
+                memset(fake_jump, 0, sizeof(*fake_jump));
+                INIT_LIST_HEAD(&fake_jump->alts);
+                clear_insn_state(&fake_jump->state);
+
+                fake_jump->sec = special_alt->new_sec;
+                fake_jump->offset = -1;
+                fake_jump->type = INSN_JUMP_UNCONDITIONAL;
+                fake_jump->jump_dest = list_next_entry(last_orig_insn, list);
+                fake_jump->ignore = true;
         }
-        memset(fake_jump, 0, sizeof(*fake_jump));
-        INIT_LIST_HEAD(&fake_jump->alts);
-        clear_insn_state(&fake_jump->state);
-
-        fake_jump->sec = special_alt->new_sec;
-        fake_jump->offset = -1;
-        fake_jump->type = INSN_JUMP_UNCONDITIONAL;
-        fake_jump->jump_dest = list_next_entry(last_orig_insn, list);
-        fake_jump->ignore = true;
 
         if (!special_alt->new_len) {
+                if (!fake_jump) {
+                        WARN("%s: empty alternative at end of section",
+                             special_alt->orig_sec->name);
+                        return -1;
+                }
+
                 *new_insn = fake_jump;
                 return 0;
         }
@@ -648,6 +647,8 @@ static int handle_group_alt(struct objtool_file *file,
 
                 last_new_insn = insn;
 
+                insn->ignore = orig_insn->ignore_alts;
+
                 if (insn->type != INSN_JUMP_CONDITIONAL &&
                     insn->type != INSN_JUMP_UNCONDITIONAL)
                         continue;
@@ -656,8 +657,14 @@ static int handle_group_alt(struct objtool_file *file,
                         continue;
 
                 dest_off = insn->offset + insn->len + insn->immediate;
-                if (dest_off == special_alt->new_off + special_alt->new_len)
+                if (dest_off == special_alt->new_off + special_alt->new_len) {
+                        if (!fake_jump) {
+                                WARN("%s: alternative jump to end of section",
+                                     special_alt->orig_sec->name);
+                                return -1;
+                        }
                         insn->jump_dest = fake_jump;
+                }
 
                 if (!insn->jump_dest) {
                         WARN_FUNC("can't find alternative jump destination",
@@ -672,7 +679,8 @@ static int handle_group_alt(struct objtool_file *file,
                 return -1;
         }
 
-        list_add(&fake_jump->list, &last_new_insn->list);
+        if (fake_jump)
+                list_add(&fake_jump->list, &last_new_insn->list);
 
         return 0;
 }
@@ -729,10 +737,6 @@ static int add_special_section_alts(struct objtool_file *file)
                         goto out;
                 }
 
-                /* Ignore retpoline alternatives. */
-                if (orig_insn->ignore_alts)
-                        continue;
-
                 new_insn = NULL;
                 if (!special_alt->group || special_alt->new_len) {
                         new_insn = find_insn(file, special_alt->new_sec,
@@ -1089,11 +1093,11 @@ static int decode_sections(struct objtool_file *file)
         if (ret)
                 return ret;
 
-        ret = add_call_destinations(file);
+        ret = add_special_section_alts(file);
         if (ret)
                 return ret;
 
-        ret = add_special_section_alts(file);
+        ret = add_call_destinations(file);
         if (ret)
                 return ret;
 
@@ -1720,10 +1724,12 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
 
                 insn->visited = true;
 
-                list_for_each_entry(alt, &insn->alts, list) {
-                        ret = validate_branch(file, alt->insn, state);
-                        if (ret)
-                                return 1;
+                if (!insn->ignore_alts) {
+                        list_for_each_entry(alt, &insn->alts, list) {
+                                ret = validate_branch(file, alt->insn, state);
+                                if (ret)
+                                        return 1;
+                        }
                 }
 
                 switch (insn->type) {