diff options
author | Josh Poimboeuf <jpoimboe@redhat.com> | 2022-04-12 01:10:31 +0200 |
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committer | Peter Zijlstra <peterz@infradead.org> | 2022-04-19 21:58:53 +0200 |
commit | 34c861e806478ac2ea4032721defbf1d6967df08 (patch) | |
tree | 269a298da66a4fb2d61878b7f6b5217d9234867e | |
parent | objtool: Don't set 'jump_dest' for sibling calls (diff) | |
download | linux-34c861e806478ac2ea4032721defbf1d6967df08.tar.xz linux-34c861e806478ac2ea4032721defbf1d6967df08.zip |
objtool: Fix sibling call detection in alternatives
In add_jump_destinations(), sibling call detection requires 'insn->func'
to be valid. But alternative instructions get their 'func' set in
handle_group_alt(), which runs *after* add_jump_destinations(). So
sibling calls in alternatives code don't get properly detected.
Fix that by changing the initialization order: call
add_special_section_alts() *before* add_jump_destinations().
This also means the special case for a missing 'jump_dest' in
add_jump_destinations() can be removed, as it has already been dealt
with.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/c02e0a0a2a4286b5f848d17c77fdcb7e0caf709c.1649718562.git.jpoimboe@redhat.com
Diffstat (limited to '')
-rw-r--r-- | tools/objtool/check.c | 36 |
1 files changed, 17 insertions, 19 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 6f492789c8c0..0f5d3de30e0d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1277,6 +1277,13 @@ static int add_jump_destinations(struct objtool_file *file) unsigned long dest_off; for_each_insn(file, insn) { + if (insn->jump_dest) { + /* + * handle_group_alt() may have previously set + * 'jump_dest' for some alternatives. + */ + continue; + } if (!is_static_jump(insn)) continue; @@ -1308,15 +1315,6 @@ static int add_jump_destinations(struct objtool_file *file) jump_dest = find_insn(file, dest_sec, dest_off); if (!jump_dest) { - - /* - * This is a special case where an alt instruction - * jumps past the end of the section. These are - * handled later in handle_group_alt(). - */ - if (!strcmp(insn->sec->name, ".altinstr_replacement")) - continue; - WARN_FUNC("can't find jump dest instruction at %s+0x%lx", insn->sec, insn->offset, dest_sec->name, dest_off); @@ -1549,13 +1547,13 @@ static int handle_group_alt(struct objtool_file *file, continue; dest_off = arch_jump_destination(insn); - if (dest_off == special_alt->new_off + special_alt->new_len) + if (dest_off == special_alt->new_off + special_alt->new_len) { insn->jump_dest = next_insn_same_sec(file, last_orig_insn); - - if (!insn->jump_dest) { - WARN_FUNC("can't find alternative jump destination", - insn->sec, insn->offset); - return -1; + if (!insn->jump_dest) { + WARN_FUNC("can't find alternative jump destination", + insn->sec, insn->offset); + return -1; + } } } @@ -2254,14 +2252,14 @@ static int decode_sections(struct objtool_file *file) return ret; /* - * Must be before add_special_section_alts() as that depends on - * jump_dest being set. + * Must be before add_jump_destinations(), which depends on 'func' + * being set for alternatives, to enable proper sibling call detection. */ - ret = add_jump_destinations(file); + ret = add_special_section_alts(file); if (ret) return ret; - ret = add_special_section_alts(file); + ret = add_jump_destinations(file); if (ret) return ret; |