scripts/decode_stacktrace.sh: add '-h' flag

When no parameters are passed, the usage instructions are presented only
when debuginfod-find is not found.  This makes sense because with
debuginfod none of the positional parameters are needed.  However it means
that users having debuginfod-find installed will have no chance of reading
the usage text without opening the file.

Many programs have a '-h' flag to get the usage, so add such a flag.
Invoking 'scripts/decode_stacktrace.sh -h' will now show the usage text
and exit.

Link: https://lkml.kernel.org/r/20240823-decode_stacktrace-find_module-improvements-v2-3-d7a57d35558b@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Cc: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index bac7ea8ee24f59b1a700a5d70e77712fe05c67df..826836d264c6a507394d935e175f9582c18e9ee1 100755 (executable)
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -7,6 +7,7 @@ usage() {
        echo "Usage:"
        echo "  $0 -r <release>"
        echo "  $0 [<vmlinux> [<base_path>|auto [<modules_path>]]]"
+       echo "  $0 -h"
 }
 
 # Try to find a Rust demangler
@@ -33,7 +34,10 @@ READELF=${UTIL_PREFIX}readelf${UTIL_SUFFIX}
 ADDR2LINE=${UTIL_PREFIX}addr2line${UTIL_SUFFIX}
 NM=${UTIL_PREFIX}nm${UTIL_SUFFIX}
 
-if [[ $1 == "-r" ]] ; then
+if [[ $1 == "-h" ]] ; then
+       usage
+       exit 0
+elif [[ $1 == "-r" ]] ; then
        vmlinux=""
        basepath="auto"
        modpath=""