kselftest/arm64: sme: Provide streaming mode SVE stress test

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.

Signed-off-by: Mark Brown <[e-mail]>
Reviewed-by: Shuah Khan <[e-mail]>
Acked-by: Catalin Marinas <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Catalin Marinas <[e-mail]>

tools/testing/selftests/arm64/fp/.gitignore

···
 sve-probe-vls
 sve-ptrace
 sve-test
+ssve-test
 vec-syscfg
 vlset

tools/testing/selftests/arm64/fp/Makefile

···
 TEST_PROGS_EXTENDED := fp-pidbench fpsimd-test fpsimd-stress \
 	rdvl-sme rdvl-sve \
 	sve-test sve-stress \
+	ssve-test ssve-stress \
 	vlset
 
 all: $(TEST_GEN_PROGS) $(TEST_PROGS_EXTENDED)
···
 sve-probe-vls: sve-probe-vls.o rdvl.o
 sve-test: sve-test.o asm-utils.o
 	$(CC) -nostdlib $^ -o $@
+ssve-test: sve-test.S asm-utils.o
+	$(CC) -DSSVE -nostdlib $^ -o $@
 vec-syscfg: vec-syscfg.o rdvl.o
 vlset: vlset.o
 

tools/testing/selftests/arm64/fp/ssve-stress

···
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright (C) 2015-2019 ARM Limited.
+# Original author: Dave Martin <[e-mail]>
+
+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

tools/testing/selftests/arm64/fp/sve-test.S

···
 #include <asm/unistd.h>
 #include "assembler.h"
 #include "asm-offsets.h"
+#include "sme-inst.h"
 
 #define NZR	32
 #define NPR	16
···
 // We fill the upper lanes of FFR with zeros.
 // Beware: corrupts P0.
 function setup_ffr
+#ifndef SSVE
 	mov	x4, x30
 
 	and	w0, w0, #0x3
···
 	wrffr	p0.b
 
 	ret	x4
+#else
+	ret
+#endif
 endfunction
 
 // Trivial memory compare: compare x2 bytes starting at address x0 with
···
 // Beware -- corrupts P0.
 // Clobbers x0-x5.
 function check_ffr
+#ifndef SSVE
 	mov	x3, x30
 
 	ldr	x4, =scratch
···
 	mov	x2, x5
 	mov	x30, x3
 	b	memcmp
+#else
+	ret
+#endif
 endfunction
 
 // Any SVE register modified here can cause corruption in the main
···
 	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
···
 .globl _start
 function _start
 _start:
+#ifdef SSVE
+	puts	"Streaming mode "
+	smstart_sm
+#endif
+
 	// Sanity-check and report the vector length
 
 	rdvl	x19, #8
···
 	mov	w2, #SA_SIGINFO
 	orr	w2, w2, #SA_NODEFER
 	bl	setsignal
+
+#ifdef SSVE
+	smstart_sm		// syscalls will have exited streaming mode
+#endif
 
 	mov	x22, #0		// generation number, increments per iteration
 .Ltest_loop: