The following commit has been merged into the objtool/core branch of tip: Commit-ID: 6b5dd716da8fc3aba65e6b7d992dea0cee2f9528 Gitweb: https://git.kernel.org/tip/6b5dd716da8fc3aba65e6b7d992dea0cee2f9528 Author: Sami Tolvanen <samitolva...@google.com> AuthorDate: Tue, 21 Apr 2020 15:08:43 -07:00 Committer: Peter Zijlstra <pet...@infradead.org> CommitterDate: Fri, 15 May 2020 10:35:13 +02:00
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 <jpoim...@redhat.com> Signed-off-by: Sami Tolvanen <samitolva...@google.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Link: https://lkml.kernel.org/r/20200421220843.188260-3-samitolva...@google.com --- tools/objtool/check.c | 36 +++++++++++++++++------------------- 1 file changed, 17 insertions(+), 19 deletions(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 196a551..6b2b458 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;
