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authorJosh Poimboeuf <jpoimboe@redhat.com>2020-12-18 23:19:32 +0300
committerJosh Poimboeuf <jpoimboe@redhat.com>2021-01-14 18:53:48 +0300
commitb23cc71c62747f2e4c3e56138872cf47e1294f8a (patch)
tree5c8b897f91385b546a6f7ab7115ac3d0a41e0801 /tools
parentab4e0744e99b87e1a223e89fc3c9ae44f727c9a6 (diff)
downloadlinux-b23cc71c62747f2e4c3e56138872cf47e1294f8a.tar.xz
objtool: Add 'alt_group' struct
Create a new struct associated with each group of alternatives instructions. This will help with the removal of fake jumps, and more importantly with adding support for stack layout changes in alternatives. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/objtool/check.c29
-rw-r--r--tools/objtool/include/objtool/check.h13
2 files changed, 35 insertions, 7 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 8976047cb648..9aa324b14d5d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -992,20 +992,28 @@ static int handle_group_alt(struct objtool_file *file,
struct instruction *orig_insn,
struct instruction **new_insn)
{
- static unsigned int alt_group_next_index = 1;
struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump = NULL;
- unsigned int alt_group = alt_group_next_index++;
+ struct alt_group *orig_alt_group, *new_alt_group;
unsigned long dest_off;
+
+ orig_alt_group = malloc(sizeof(*orig_alt_group));
+ if (!orig_alt_group) {
+ WARN("malloc failed");
+ return -1;
+ }
last_orig_insn = NULL;
insn = orig_insn;
sec_for_each_insn_from(file, insn) {
if (insn->offset >= special_alt->orig_off + special_alt->orig_len)
break;
- insn->alt_group = alt_group;
+ insn->alt_group = orig_alt_group;
last_orig_insn = insn;
}
+ orig_alt_group->orig_group = NULL;
+ orig_alt_group->first_insn = orig_insn;
+ orig_alt_group->last_insn = last_orig_insn;
if (next_insn_same_sec(file, last_orig_insn)) {
fake_jump = malloc(sizeof(*fake_jump));
@@ -1036,8 +1044,13 @@ static int handle_group_alt(struct objtool_file *file,
return 0;
}
+ new_alt_group = malloc(sizeof(*new_alt_group));
+ if (!new_alt_group) {
+ WARN("malloc failed");
+ return -1;
+ }
+
last_new_insn = NULL;
- alt_group = alt_group_next_index++;
insn = *new_insn;
sec_for_each_insn_from(file, insn) {
struct reloc *alt_reloc;
@@ -1049,7 +1062,7 @@ static int handle_group_alt(struct objtool_file *file,
insn->ignore = orig_insn->ignore_alts;
insn->func = orig_insn->func;
- insn->alt_group = alt_group;
+ insn->alt_group = new_alt_group;
/*
* Since alternative replacement code is copy/pasted by the
@@ -1098,6 +1111,10 @@ static int handle_group_alt(struct objtool_file *file,
return -1;
}
+ new_alt_group->orig_group = orig_alt_group;
+ new_alt_group->first_insn = *new_insn;
+ new_alt_group->last_insn = last_new_insn;
+
if (fake_jump)
list_add(&fake_jump->list, &last_new_insn->list);
@@ -2451,7 +2468,7 @@ static int validate_return(struct symbol *func, struct instruction *insn, struct
static void fill_alternative_cfi(struct objtool_file *file, struct instruction *insn)
{
struct instruction *first_insn = insn;
- int alt_group = insn->alt_group;
+ struct alt_group *alt_group = insn->alt_group;
sec_for_each_insn_continue(file, insn) {
if (insn->alt_group != alt_group)
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index df1e3e8ed204..7893e9783084 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -19,6 +19,17 @@ struct insn_state {
s8 instr;
};
+struct alt_group {
+ /*
+ * Pointer from a replacement group to the original group. NULL if it
+ * *is* the original group.
+ */
+ struct alt_group *orig_group;
+
+ /* First and last instructions in the group */
+ struct instruction *first_insn, *last_insn;
+};
+
struct instruction {
struct list_head list;
struct hlist_node hash;
@@ -34,7 +45,7 @@ struct instruction {
s8 instr;
u8 visited;
u8 ret_offset;
- int alt_group;
+ struct alt_group *alt_group;
struct symbol *call_dest;
struct instruction *jump_dest;
struct instruction *first_jump_src;