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 <peterz@infradead.org>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/3eb3f091fd6bd9caba50392ceab98ce756804f3b.1650578171.git.jpoimboe@redhat.com
This commit is contained in:
Josh Poimboeuf 2022-04-21 14:56:55 -07:00 committed by Josh Poimboeuf
parent 4bc7800588
commit 21e350233b
1 changed files with 29 additions and 0 deletions

29
scripts/objdump-func Executable file
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#!/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; } }'