perf test: Replace legacy `...` with $(...)

As detailed in https://www.shellcheck.net/wiki/SC2006:

The use of `...` is legacy syntax with several issues:
1. It has a series of undefined behaviors related to quoting in POSIX.
2. It imposes a custom escaping mode with surprising results.
3. It's exceptionally hard to nest.

$(...) command substitution has none of these problems,
and is therefore strongly encouraged.

Signed-off-by: Diederik de Haas <didi.debian@cknow.org>
Acked-by: Carsten Haitzler <carsten.haitzler@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230201214945.127474-3-didi.debian@cknow.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/tests/shell/lib/coresight.sh b/tools/perf/tests/shell/lib/coresight.sh
index 7e27e5c5bc9c5f51999e5727769c9e62c907df5f..6c3d34ec64d8b7bd66a42e78f6b7a4c36d899ba5 100644 (file)
--- a/tools/perf/tests/shell/lib/coresight.sh
+++ b/tools/perf/tests/shell/lib/coresight.sh
@@ -58,9 +58,9 @@ perf_dump_aux_verify() {
        # compiler may produce different code depending on the compiler and
        # optimization options, so this is rough just to see if we're
        # either missing almost all the data or all of it
-       ATOM_FX_NUM=`grep -c I_ATOM_F "$DUMP"`
-       ASYNC_NUM=`grep -c I_ASYNC "$DUMP"`
-       TRACE_INFO_NUM=`grep -c I_TRACE_INFO "$DUMP"`
+       ATOM_FX_NUM=$(grep -c I_ATOM_F "$DUMP")
+       ASYNC_NUM=$(grep -c I_ASYNC "$DUMP")
+       TRACE_INFO_NUM=$(grep -c I_TRACE_INFO "$DUMP")
        rm -f "$DUMP"
 
        # Arguments provide minimums for a pass
@@ -96,18 +96,18 @@ perf_dump_aux_tid_verify() {
 
        # The TID test tools will print a TID per stdout line that are being
        # tested
-       TIDS=`cat "$2"`
+       TIDS=$(cat "$2")
        # Scan the perf report to find the TIDs that are actually CID in hex
        # and build a list of the ones found
-       FOUND_TIDS=`perf report --stdio --dump -i "$1" | \
+       FOUND_TIDS=$(perf report --stdio --dump -i "$1" | \
                        grep -o "CID=0x[0-9a-z]\+" | sed 's/CID=//g' | \
-                       uniq | sort | uniq`
+                       uniq | sort | uniq)
        # No CID=xxx found - maybe your kernel is reporting these as
        # VMID=xxx so look there
        if test -z "$FOUND_TIDS"; then
-               FOUND_TIDS=`perf report --stdio --dump -i "$1" | \
+               FOUND_TIDS=$(perf report --stdio --dump -i "$1" | \
                                grep -o "VMID=0x[0-9a-z]\+" | sed 's/VMID=//g' | \
-                               uniq | sort | uniq`
+                               uniq | sort | uniq)
        fi
 
        # Iterate over the list of TIDs that the test says it has and find
@@ -116,7 +116,7 @@ perf_dump_aux_tid_verify() {
        for TID2 in $TIDS; do
                FOUND=""
                for TIDHEX in $FOUND_TIDS; do
-                       TID=`printf "%i" $TIDHEX`
+                       TID=$(printf "%i" $TIDHEX)
                        if test "$TID" -eq "$TID2"; then
                                FOUND="y"
                                break