From: Sami Tolvanen <samitolvanen@google.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>,
Kristen Carlson Accardi <kristen@linux.intel.com>,
linux-kernel@vger.kernel.org,
Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH v2 2/2] objtool: optimize add_dead_ends for split sections
Date: Tue, 21 Apr 2020 15:08:43 -0700 [thread overview]
Message-ID: <20200421220843.188260-3-samitolvanen@google.com> (raw)
In-Reply-To: <20200421220843.188260-1-samitolvanen@google.com>
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>
---
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 4b170fd08a28..4f1d405420a4 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -303,6 +303,19 @@ static int decode_instructions(struct objtool_file *file)
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.
*/
@@ -311,7 +324,6 @@ 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
@@ -337,15 +349,8 @@ 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;
@@ -379,15 +384,8 @@ 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 reachable insn at %s+0x%x",
rela->sym->sec->name, rela->addend);
return -1;
--
2.26.1.301.g55bc3eb7cb9-goog
next prev parent reply other threads:[~2020-04-21 22:09 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 18:07 [PATCH 0/3] objtool: add support for >64k sections Sami Tolvanen
2020-04-21 18:07 ` [PATCH 1/3] objtool: use gelf_getsymshndx to handle " Sami Tolvanen
2020-04-21 20:11 ` Kees Cook
2020-04-21 18:07 ` [PATCH 2/3] objtool: optimize insn_hash for split sections Sami Tolvanen
2020-04-21 19:47 ` Peter Zijlstra
2020-04-21 20:13 ` Kees Cook
2020-04-21 20:20 ` Sami Tolvanen
2020-04-21 18:07 ` [PATCH 3/3] objtool: optimize add_dead_ends " Sami Tolvanen
2020-04-21 20:13 ` Josh Poimboeuf
2020-04-21 20:17 ` Kees Cook
2020-04-21 22:02 ` Sami Tolvanen
2020-04-21 20:14 ` Kees Cook
2020-04-21 20:11 ` [PATCH 0/3] objtool: add support for >64k sections Kees Cook
2020-04-21 22:08 ` [PATCH v2 0/2] " Sami Tolvanen
2020-04-21 22:08 ` [PATCH v2 1/2] objtool: use gelf_getsymshndx to handle " Sami Tolvanen
2020-05-15 17:22 ` [tip: objtool/core] " tip-bot2 for Sami Tolvanen
2020-04-21 22:08 ` Sami Tolvanen [this message]
2020-04-21 23:43 ` [PATCH v2 2/2] objtool: optimize add_dead_ends for split sections Kees Cook
2020-05-15 17:22 ` [tip: objtool/core] " tip-bot2 for Sami Tolvanen
2020-04-21 23:52 ` [PATCH v2 0/2] objtool: add support for >64k sections Josh Poimboeuf
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