2022-04-22 06:12:30

by Josh Poimboeuf

[permalink] [raw]
Subject: [PATCH v4] scripts: Create objdump-func helper script

Add a simple script which disassembles a single function from an object
file. Comes in handy for objtool warnings and kernel stack traces.

Originally-by: Peter Zijlstra <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
---
v4:
- allow extra args to be provided at the end
- match ".cold", etc

scripts/objdump-func | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
create mode 100755 scripts/objdump-func

diff --git a/scripts/objdump-func b/scripts/objdump-func
new file mode 100755
index 000000000000..4eb463dd9f52
--- /dev/null
+++ b/scripts/objdump-func
@@ -0,0 +1,29 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Disassemble a single function.
+#
+# usage: objdump-func <file> <func>
+
+set -o errexit
+set -o nounset
+
+OBJDUMP="${CROSS_COMPILE:-}objdump"
+
+command -v gawk >/dev/null 2>&1 || die "gawk isn't installed"
+
+usage() {
+ echo "usage: objdump-func <file> <func>" >&2
+ exit 1
+}
+
+[[ $# -lt 2 ]] && usage
+
+OBJ=$1; shift
+FUNC=$1; shift
+
+# Secret feature to allow adding extra objdump args at the end
+EXTRA_ARGS=$@
+
+# Note this also matches compiler-added suffixes like ".cold", etc
+${OBJDUMP} -wdr $EXTRA_ARGS $OBJ | gawk -M -v f=$FUNC '/^$/ { P=0; } $0 ~ "<" f "(\\..*)?>:" { P=1; O=strtonum("0x" $1); } { if (P) { o=strtonum("0x" $1); printf("%04x ", o-O); print $0; } }'
--
2.34.1


Subject: [tip: objtool/core] scripts: Create objdump-func helper script

The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 21e350233b07619dbfc3ce606ff1fc468fce2d82
Gitweb: https://git.kernel.org/tip/21e350233b07619dbfc3ce606ff1fc468fce2d82
Author: Josh Poimboeuf <[email protected]>
AuthorDate: Thu, 21 Apr 2022 14:56:55 -07:00
Committer: Josh Poimboeuf <[email protected]>
CommitterDate: Thu, 12 May 2022 10:08:43 -07:00

scripts: Create objdump-func helper script

Add a simple script which disassembles a single function from an object
file. Comes in handy for objtool warnings and kernel stack traces.

Originally-by: Peter Zijlstra <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Link: https://lore.kernel.org/r/3eb3f091fd6bd9caba50392ceab98ce756804f3b.1650578171.git.jpoimboe@redhat.com
---
scripts/objdump-func | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
create mode 100755 scripts/objdump-func

diff --git a/scripts/objdump-func b/scripts/objdump-func
new file mode 100755
index 0000000..4eb463d
--- /dev/null
+++ b/scripts/objdump-func
@@ -0,0 +1,29 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Disassemble a single function.
+#
+# usage: objdump-func <file> <func>
+
+set -o errexit
+set -o nounset
+
+OBJDUMP="${CROSS_COMPILE:-}objdump"
+
+command -v gawk >/dev/null 2>&1 || die "gawk isn't installed"
+
+usage() {
+ echo "usage: objdump-func <file> <func>" >&2
+ exit 1
+}
+
+[[ $# -lt 2 ]] && usage
+
+OBJ=$1; shift
+FUNC=$1; shift
+
+# Secret feature to allow adding extra objdump args at the end
+EXTRA_ARGS=$@
+
+# Note this also matches compiler-added suffixes like ".cold", etc
+${OBJDUMP} -wdr $EXTRA_ARGS $OBJ | gawk -M -v f=$FUNC '/^$/ { P=0; } $0 ~ "<" f "(\\..*)?>:" { P=1; O=strtonum("0x" $1); } { if (P) { o=strtonum("0x" $1); printf("%04x ", o-O); print $0; } }'