[PATCH V16 8/8] perf: test: Extend branch stack sampling test for Arm64 BRBE

[Anshuman Khandual <anshuman.khandual@arm.com>]

From: James Clark <james.clark@arm.com>

Add Arm64 BRBE-specific testing to the existing branch stack sampling test.
The test currently passes on the Arm FVP RevC model, but no hardware has
been tested yet.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: linux-perf-users@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Co-developed-by: German Gomez <german.gomez@arm.com>
Signed-off-by: German Gomez <german.gomez@arm.com>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 tools/perf/tests/builtin-test.c        |  1 +
 tools/perf/tests/shell/test_brstack.sh | 42 ++++++++++++++++++++++++--
 tools/perf/tests/tests.h               |  1 +
 tools/perf/tests/workloads/Build       |  2 ++
 tools/perf/tests/workloads/traploop.c  | 39 ++++++++++++++++++++++++
 5 files changed, 82 insertions(+), 3 deletions(-)
 create mode 100644 tools/perf/tests/workloads/traploop.c

diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 4a5973f9bb9b..bd7202ff5cca 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -139,6 +139,7 @@ static struct test_workload *workloads[] = {
 	&workload__sqrtloop,
 	&workload__brstack,
 	&workload__datasym,
+	&workload__traploop
 };
 
 static int num_subtests(const struct test_suite *t)
diff --git a/tools/perf/tests/shell/test_brstack.sh b/tools/perf/tests/shell/test_brstack.sh
index 928790f35747..6a4069c930e8 100755
--- a/tools/perf/tests/shell/test_brstack.sh
+++ b/tools/perf/tests/shell/test_brstack.sh
@@ -53,12 +53,43 @@ test_user_branches() {
 	grep -E -m1 "^brstack_foo\+[^ ]*/brstack_bench\+[^ ]*/RET/.*$"	$TMPDIR/perf.script
 	grep -E -m1 "^brstack_bench\+[^ ]*/brstack_bench\+[^ ]*/COND/.*$"	$TMPDIR/perf.script
 	grep -E -m1 "^brstack\+[^ ]*/brstack\+[^ ]*/UNCOND/.*$"		$TMPDIR/perf.script
+
+	if is_arm64; then
+		# in arm64 with BRBE, we get IRQ entries that correspond
+		# to any point in the process
+		grep -m1 "/IRQ/"					$TMPDIR/perf.script
+	fi
 	set +x
 
 	# some branch types are still not being tested:
 	# IND COND_CALL COND_RET SYSCALL SYSRET IRQ SERROR NO_TX
 }
 
+test_arm64_trap_eret_branches() {
+	echo "Testing trap & eret branches (arm64 brbe)"
+	perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u -- \
+		perf test -w traploop 250
+	perf script -i $TMPDIR/perf.data --fields brstacksym | tr ' ' '\n' > $TMPDIR/perf.script
+	set -x
+	# BRBINF<n>.TYPE == TRAP are mapped to PERF_BR_SYSCALL by the BRBE driver
+	grep -E -m1 "^trap_bench\+[^ ]*/\[unknown\][^ ]*/SYSCALL/" $TMPDIR/perf.script
+	grep -E -m1 "^\[unknown\][^ ]*/trap_bench\+[^ ]*/ERET/"	$TMPDIR/perf.script
+	set +x
+}
+
+test_arm64_kernel_branches() {
+	echo "Testing kernel branches (arm64 brbe)"
+	# skip if perf doesn't have enough privileges
+	if ! perf record --branch-filter any,k -o- -- true > /dev/null; then
+		echo "[skipped: not enough privileges]"
+		return 0
+	fi
+	perf record -o $TMPDIR/perf.data --branch-filter any,k -- uname -a
+	perf script -i $TMPDIR/perf.data --fields brstack | tr ' ' '\n' > $TMPDIR/perf.script
+	grep -E -m1 "0xffff[0-9a-f]{12}" $TMPDIR/perf.script
+	! egrep -E -m1 "0x0000[0-9a-f]{12}" $TMPDIR/perf.script
+}
+
 # first argument <arg0> is the argument passed to "--branch-stack <arg0>,save_type,u"
 # second argument are the expected branch types for the given filter
 test_filter() {
@@ -81,11 +112,16 @@ set -e
 
 test_user_branches
 
-test_filter "any_call"	"CALL|IND_CALL|COND_CALL|SYSCALL|IRQ"
+if is_arm64; then
+	test_arm64_trap_eret_branches
+	test_arm64_kernel_branches
+fi
+
+test_filter "any_call"	"CALL|IND_CALL|COND_CALL|SYSCALL|IRQ|FAULT_DATA|FAULT_INST"
 test_filter "call"	"CALL|SYSCALL"
 test_filter "cond"	"COND"
 test_filter "any_ret"	"RET|COND_RET|SYSRET|ERET"
 
 test_filter "call,cond"		"CALL|SYSCALL|COND"
-test_filter "any_call,cond"		"CALL|IND_CALL|COND_CALL|IRQ|SYSCALL|COND"
-test_filter "cond,any_call,any_ret"	"COND|CALL|IND_CALL|COND_CALL|SYSCALL|IRQ|RET|COND_RET|SYSRET|ERET"
+test_filter "any_call,cond"		"CALL|IND_CALL|COND_CALL|IRQ|SYSCALL|COND|FAULT_DATA|FAULT_INST"
+test_filter "cond,any_call,any_ret"	"COND|CALL|IND_CALL|COND_CALL|SYSCALL|IRQ|RET|COND_RET|SYSRET|ERET|FAULT_DATA|FAULT_INST"
diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
index dad3d7414142..6d3d575352d5 100644
--- a/tools/perf/tests/tests.h
+++ b/tools/perf/tests/tests.h
@@ -205,6 +205,7 @@ DECLARE_WORKLOAD(leafloop);
 DECLARE_WORKLOAD(sqrtloop);
 DECLARE_WORKLOAD(brstack);
 DECLARE_WORKLOAD(datasym);
+DECLARE_WORKLOAD(traploop);
 
 extern const char *dso_to_test;
 extern const char *test_objdump_path;
diff --git a/tools/perf/tests/workloads/Build b/tools/perf/tests/workloads/Build
index a1f34d5861e3..a9dc93d8468b 100644
--- a/tools/perf/tests/workloads/Build
+++ b/tools/perf/tests/workloads/Build
@@ -6,8 +6,10 @@ perf-y += leafloop.o
 perf-y += sqrtloop.o
 perf-y += brstack.o
 perf-y += datasym.o
+perf-y += traploop.o
 
 CFLAGS_sqrtloop.o         = -g -O0 -fno-inline -U_FORTIFY_SOURCE
 CFLAGS_leafloop.o         = -g -O0 -fno-inline -fno-omit-frame-pointer -U_FORTIFY_SOURCE
 CFLAGS_brstack.o          = -g -O0 -fno-inline -U_FORTIFY_SOURCE
 CFLAGS_datasym.o          = -g -O0 -fno-inline -U_FORTIFY_SOURCE
+CFLAGS_traploop.o         = -g -O0 -fno-inline -U_FORTIFY_SOURCE
diff --git a/tools/perf/tests/workloads/traploop.c b/tools/perf/tests/workloads/traploop.c
new file mode 100644
index 000000000000..7dac94897e49
--- /dev/null
+++ b/tools/perf/tests/workloads/traploop.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdlib.h>
+#include "../tests.h"
+
+#define BENCH_RUNS 999999
+
+static volatile int cnt;
+
+#ifdef __aarch64__
+static void trap_bench(void)
+{
+	unsigned long val;
+
+	asm("mrs %0, ID_AA64ISAR0_EL1" : "=r" (val));   /* TRAP + ERET */
+}
+#else
+static void trap_bench(void)
+{
+
+}
+#endif
+
+static int traploop(int argc, const char **argv)
+{
+	int num_loops = BENCH_RUNS;
+
+	if (argc > 0)
+		num_loops = atoi(argv[0]);
+
+	while (1) {
+		if ((cnt++) > num_loops)
+			break;
+
+		trap_bench();
+	}
+	return 0;
+}
+
+DEFINE_WORKLOAD(traploop);
-- 
2.25.1