[PATCH v2 38/42] kselftest/arm64: sme: Provide streaming mode SVE stress test

[Mark Brown <broonie@kernel.org>]

One of the features of SME is the addition of streaming mode, in which we
have access to a set of streaming mode SVE registers at the SME vector
length. Since these are accessed using the SVE instructions let's reuse
the existing SVE stress test for testing with a compile time option for
controlling the few small differences needed:

 - Enter streaming mode immediately on starting the program.
 - In streaming mode FFR is removed so skip reading and writing FFR.

In order to avoid requiring a cutting edge toolchain with SME support
use the op/CR form for specifying SVCR.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/fp/.gitignore  |  1 +
 tools/testing/selftests/arm64/fp/Makefile    |  3 +
 tools/testing/selftests/arm64/fp/ssve-stress | 59 ++++++++++++++++++++
 tools/testing/selftests/arm64/fp/sve-test.S  | 30 ++++++++++
 4 files changed, 93 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/fp/ssve-stress

diff --git a/tools/testing/selftests/arm64/fp/.gitignore b/tools/testing/selftests/arm64/fp/.gitignore
index 885dd592807b..73c600e1ab81 100644
--- a/tools/testing/selftests/arm64/fp/.gitignore
+++ b/tools/testing/selftests/arm64/fp/.gitignore
@@ -4,5 +4,6 @@ rdvl-sve
 sve-probe-vls
 sve-ptrace
 sve-test
+ssve-test
 vec-syscfg
 vlset
diff --git a/tools/testing/selftests/arm64/fp/Makefile b/tools/testing/selftests/arm64/fp/Makefile
index ff1c8fde3aed..11dbe05c5070 100644
--- a/tools/testing/selftests/arm64/fp/Makefile
+++ b/tools/testing/selftests/arm64/fp/Makefile
@@ -5,6 +5,7 @@ TEST_GEN_PROGS := sve-ptrace sve-probe-vls vec-syscfg
 TEST_PROGS_EXTENDED := fpsimd-test fpsimd-stress \
 	rdvl-sme rdvl-sve \
 	sve-test sve-stress \
+	ssve-test ssve-stress \
 	vlset
 
 all: $(TEST_GEN_PROGS) $(TEST_PROGS_EXTENDED)
@@ -17,6 +18,8 @@ sve-ptrace: sve-ptrace.o
 sve-probe-vls: sve-probe-vls.o rdvl.o
 sve-test: sve-test.o
 	$(CC) -nostdlib $^ -o $@
+ssve-test: sve-test.S
+	$(CC) -DSSVE -nostdlib $^ -o $@
 vec-syscfg: vec-syscfg.o rdvl.o
 vlset: vlset.o
 
diff --git a/tools/testing/selftests/arm64/fp/ssve-stress b/tools/testing/selftests/arm64/fp/ssve-stress
new file mode 100644
index 000000000000..e2bd2cc184ad
--- /dev/null
+++ b/tools/testing/selftests/arm64/fp/ssve-stress
@@ -0,0 +1,59 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright (C) 2015-2019 ARM Limited.
+# Original author: Dave Martin <Dave.Martin@arm.com>
+
+set -ue
+
+NR_CPUS=`nproc`
+
+pids=
+logs=
+
+cleanup () {
+	trap - INT TERM CHLD
+	set +e
+
+	if [ -n "$pids" ]; then
+		kill $pids
+		wait $pids
+		pids=
+	fi
+
+	if [ -n "$logs" ]; then
+		cat $logs
+		rm $logs
+		logs=
+	fi
+}
+
+interrupt () {
+	cleanup
+	exit 0
+}
+
+child_died () {
+	cleanup
+	exit 1
+}
+
+trap interrupt INT TERM EXIT
+
+for x in `seq 0 $((NR_CPUS * 4))`; do
+	log=`mktemp`
+	logs=$logs\ $log
+	./ssve-test >$log &
+	pids=$pids\ $!
+done
+
+# Wait for all child processes to be created:
+sleep 10
+
+while :; do
+	kill -USR1 $pids
+done &
+pids=$pids\ $!
+
+wait
+
+exit 1
diff --git a/tools/testing/selftests/arm64/fp/sve-test.S b/tools/testing/selftests/arm64/fp/sve-test.S
index e3e08d9c7020..fa52d6735b76 100644
--- a/tools/testing/selftests/arm64/fp/sve-test.S
+++ b/tools/testing/selftests/arm64/fp/sve-test.S
@@ -292,6 +292,7 @@ endfunction
 // We fill the upper lanes of FFR with zeros.
 // Beware: corrupts P0.
 function setup_ffr
+#ifndef SSVE
 	mov	x4, x30
 
 	and	w0, w0, #0x3
@@ -314,6 +315,9 @@ function setup_ffr
 	wrffr	p0.b
 
 	ret	x4
+#else
+	ret
+#endif
 endfunction
 
 // Fill x1 bytes starting at x0 with 0xae (for canary purposes)
@@ -423,6 +427,7 @@ endfunction
 // Beware -- corrupts P0.
 // Clobbers x0-x5.
 function check_ffr
+#ifndef SSVE
 	mov	x3, x30
 
 	ldr	x4, =scratch
@@ -443,6 +448,9 @@ function check_ffr
 	mov	x2, x5
 	mov	x30, x3
 	b	memcmp
+#else
+	ret
+#endif
 endfunction
 
 // Any SVE register modified here can cause corruption in the main
@@ -458,13 +466,26 @@ function irritator_handler
 	movi	v0.8b, #1
 	movi	v9.16b, #2
 	movi	v31.8b, #3
+#ifndef SSVE
 	// And P0
 	rdffr	p0.b
 	// And FFR
 	wrffr	p15.b
+#endif
+
+	ret
+endfunction
+
+#ifdef SSVE
+function enable_sm
+	// Set SVCR.SM to 1, equivalent to SMSTART SM but doesn't need a
+	// SME capable toolchain.
+	mov	x0, #1
+	msr	S3_3_C4_C2_2, x0
 
 	ret
 endfunction
+#endif
 
 function terminate_handler
 	mov	w21, w0
@@ -522,6 +543,11 @@ endfunction
 .globl _start
 function _start
 _start:
+#ifdef SSVE
+	puts	"Streaming mode "
+	bl	enable_sm
+#endif
+
 	// Sanity-check and report the vector length
 
 	rdvl	x19, #8
@@ -570,6 +596,10 @@ _start:
 	orr	w2, w2, #SA_NODEFER
 	bl	setsignal
 
+#ifdef SSVE
+	bl	enable_sm	// syscalls will have exited streaming mode
+#endif
+
 	mov	x22, #0		// generation number, increments per iteration
 .Ltest_loop:
 	rdvl	x0, #8
-- 
2.30.2