diff options
| author | Sami Tolvanen <samitolvanen@google.com> | 2020-04-21 15:08:43 -0700 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-05-15 10:35:13 +0200 |
| commit | 6b5dd716da8fc3aba65e6b7d992dea0cee2f9528 (patch) | |
| tree | 2e5c1e4a8ad1c0d6619a30a476b76bc28de29cec /tools/objtool | |
| parent | 28fe1d7bf89f8ed5be70b98a33932dbaf99345dd (diff) | |
objtool: optimize add_dead_ends for split sections
Instead of iterating through all instructions to find the last
instruction each time .rela.discard.(un)reachable points beyond the
section, use find_insn to locate the last instruction by looking at
the last bytes of the section instead.
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200421220843.188260-3-samitolvanen@google.com
Diffstat (limited to 'tools/objtool')
| -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 196a55101f3c..6b2b458a5b0e 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -322,6 +322,19 @@ err: return ret; } +static struct instruction *find_last_insn(struct objtool_file *file, + struct section *sec) +{ + struct instruction *insn = NULL; + unsigned int offset; + unsigned int end = (sec->len > 10) ? sec->len - 10 : 0; + + for (offset = sec->len - 1; offset >= end && !insn; offset--) + insn = find_insn(file, sec, offset); + + return insn; +} + /* * Mark "ud2" instructions and manually annotated dead ends. */ @@ -330,7 +343,6 @@ static int add_dead_ends(struct objtool_file *file) struct section *sec; struct rela *rela; struct instruction *insn; - bool found; /* * By default, "ud2" is a dead end unless otherwise annotated, because @@ -356,15 +368,8 @@ static int add_dead_ends(struct objtool_file *file) if (insn) insn = list_prev_entry(insn, list); else if (rela->addend == rela->sym->sec->len) { - found = false; - list_for_each_entry_reverse(insn, &file->insn_list, list) { - if (insn->sec == rela->sym->sec) { - found = true; - break; - } - } - - if (!found) { + insn = find_last_insn(file, rela->sym->sec); + if (!insn) { WARN("can't find unreachable insn at %s+0x%x", rela->sym->sec->name, rela->addend); return -1; @@ -398,15 +403,8 @@ reachable: if (insn) insn = list_prev_entry(insn, list); else if (rela->addend == rela->sym->sec->len) { - found = false; - list_for_each_entry_reverse(insn, &file->insn_list, list) { - if (insn->sec == rela->sym->sec) { - found = true; - break; - } - } - - if (!found) { + insn = find_last_insn(file, rela->sym->sec); + if (!insn) { WARN("can't find reachable insn at %s+0x%x", rela->sym->sec->name, rela->addend); return -1; |