[PATCH v4 08/15] selftests: futex2: Add wake/wait test

André Almeida
2021-06-03T20:01:06Z

Add a simple file to test wake/wait mechanism using futex2 interface.
Test three scenarios: using a common local int variable as private
futex, a shm futex as shared futex and a file-backed shared memory as a
shared futex. This should test all branches of futex_get_key().

Create helper files so more tests can evaluate futex2. While 32bit ABIs
from glibc aren't yet able to use 64 bit sized time variables, add a
temporary workaround that implements the required types and calls the
appropriated syscalls, since futex2 doesn't supports 32 bit sized time.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
---
.../selftests/futex/functional/.gitignore | 1 +
.../selftests/futex/functional/Makefile | 4 +-
.../selftests/futex/functional/futex2_wait.c | 195 ++++++++++++++++++
.../testing/selftests/futex/functional/run.sh | 3 +
.../selftests/futex/include/futex2test.h | 79 +++++++
5 files changed, 281 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/futex/functional/futex2_wait.c
create mode 100644 tools/testing/selftests/futex/include/futex2test.h

diff --git a/tools/testing/selftests/futex/functional/.gitignore b/tools/testing/selftests/futex/functional/.gitignore
index 0efcd494daab..d61f1df94360 100644
--- a/tools/testing/selftests/futex/functional/.gitignore
+++ b/tools/testing/selftests/futex/functional/.gitignore
@@ -6,3 +6,4 @@ futex_wait_private_mapped_file
futex_wait_timeout
futex_wait_uninitialized_heap
futex_wait_wouldblock
+futex2_wait
diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/testing/selftests/futex/functional/Makefile
index 23207829ec75..7142a94a7ac3 100644
--- a/tools/testing/selftests/futex/functional/Makefile
+++ b/tools/testing/selftests/futex/functional/Makefile
@@ -5,6 +5,7 @@ LDLIBS := -lpthread -lrt

HEADERS := \
../include/futextest.h \
+ ../include/futex2test.h \
../include/atomic.h \
../include/logging.h
TEST_GEN_FILES := \
@@ -14,7 +15,8 @@ TEST_GEN_FILES := \
futex_requeue_pi_signal_restart \
futex_requeue_pi_mismatched_ops \
futex_wait_uninitialized_heap \
- futex_wait_private_mapped_file
+ futex_wait_private_mapped_file \
+ futex2_wait

TEST_PROGS := run.sh

diff --git a/tools/testing/selftests/futex/functional/futex2_wait.c b/tools/testing/selftests/futex/functional/futex2_wait.c
new file mode 100644
index 000000000000..25ac6d0898f5
--- /dev/null
+++ b/tools/testing/selftests/futex/functional/futex2_wait.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/******************************************************************************
+ *
+ * Copyright Collabora Ltd., 2021
+ *
+ * DESCRIPTION
+ * Test wait/wake mechanism of futex2, using 32bit sized futexes.
+ *
+ * AUTHOR
+ * André Almeida <andrealmeid@collabora.com>
+ *
+ * HISTORY
+ * 2021-Feb-5: Initial version by André <andrealmeid@collabora.com>
+ *
+ *****************************************************************************/
+
+#include <errno.h>
+#include <error.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <pthread.h>
+#include <sys/shm.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <string.h>
+#include "futex2test.h"
+#include "logging.h"
+
+#define TEST_NAME "futex2-wait"
+#define timeout_ns 30000000
+#define WAKE_WAIT_US 10000
+#define SHM_PATH "futex2_shm_file"
+
+void *futex;
+
+void usage(char *prog)
+{
+ printf("Usage: %s\n", prog);
+ printf(" -c Use color\n");
+ printf(" -h Display this help message\n");
+ printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
+ VQUIET, VCRITICAL, VINFO);
+}
+
+static void *waiterfn(void *arg)
+{
+ struct timespec64 to64;
+ unsigned int flags = 0;
+
+ if (arg)
+ flags = *((unsigned int *) arg);
+
+ /* setting absolute timeout for futex2 */
+ if (gettime64(CLOCK_MONOTONIC, &to64))
+ error("gettime64 failed\n", errno);
+
+ to64.tv_nsec += timeout_ns;
+
+ if (to64.tv_nsec >= 1000000000) {
+ to64.tv_sec++;
+ to64.tv_nsec -= 1000000000;
+ }
+
+ if (futex2_wait(futex, 0, FUTEX_32 | flags, &to64))
+ printf("waiter failed errno %d\n", errno);
+
+ return NULL;
+}
+
+int main(int argc, char *argv[])
+{
+ unsigned int flags = FUTEX_SHARED_FLAG;
+ int res, ret = RET_PASS, fd, c, shm_id;
+ u_int32_t f_private = 0, *shared_data;
+ pthread_t waiter;
+ void *shm;
+
+ futex = &f_private;
+
+ while ((c = getopt(argc, argv, "cht:v:")) != -1) {
+ switch (c) {
+ case 'c':
+ log_color(1);
+ break;
+ case 'h':
+ usage(basename(argv[0]));
+ exit(0);
+ case 'v':
+ log_verbosity(atoi(optarg));
+ break;
+ default:
+ usage(basename(argv[0]));
+ exit(1);
+ }
+ }
+
+ ksft_print_header();
+ ksft_set_plan(3);
+ ksft_print_msg("%s: Test FUTEX2_WAIT\n", basename(argv[0]));
+
+ /* Testing a private futex */
+ info("Calling private futex2_wait on futex: %p\n", futex);
+ if (pthread_create(&waiter, NULL, waiterfn, NULL))
+ error("pthread_create failed\n", errno);
+
+ usleep(WAKE_WAIT_US);
+
+ info("Calling private futex2_wake on futex: %p\n", futex);
+ res = futex2_wake(futex, 1, FUTEX_32);
+ if (res != 1) {
+ ksft_test_result_fail("futex2_wake private returned: %d %s\n",
+ errno, strerror(errno));
+ ret = RET_FAIL;
+ } else {
+ ksft_test_result_pass("futex2_wake private\n");
+ }
+
+ /* Testing an anon page shared memory */
+ shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666);
+ if (shm_id < 0) {
+ perror("shmget");
+ exit(1);
+ }
+
+ shared_data = shmat(shm_id, NULL, 0);
+
+ *shared_data = 0;
+ futex = shared_data;
+
+ info("Calling (page anon) shared futex2_wait on futex: %p\n", futex);
+ if (pthread_create(&waiter, NULL, waiterfn, &flags))
+ error("pthread_create failed\n", errno);
+
+ usleep(WAKE_WAIT_US);
+
+ info("Calling (page anon) shared futex2_wake on futex: %p\n", futex);
+ res = futex2_wake(futex, 1, FUTEX_32 | FUTEX_SHARED_FLAG);
+ if (res != 1) {
+ ksft_test_result_fail("futex2_wake shared (page anon) returned: %d %s\n",
+ errno, strerror(errno));
+ ret = RET_FAIL;
+ } else {
+ ksft_test_result_pass("futex2_wake shared (page anon)\n");
+ }
+
+
+ /* Testing a file backed shared memory */
+ fd = open(SHM_PATH, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+ if (fd < 0) {
+ perror("open");
+ exit(1);
+ }
+
+ if (ftruncate(fd, sizeof(f_private))) {
+ perror("ftruncate");
+ exit(1);
+ }
+
+ shm = mmap(NULL, sizeof(f_private), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ if (shm == MAP_FAILED) {
+ perror("mmap");
+ exit(1);
+ }
+
+ memcpy(shm, &f_private, sizeof(f_private));
+
+ futex = shm;
+
+ info("Calling shared (file backed) futex2_wait on futex: %p\n", futex);
+ if (pthread_create(&waiter, NULL, waiterfn, &flags))
+ error("pthread_create failed\n", errno);
+
+ usleep(WAKE_WAIT_US);
+
+ info("Calling shared (file backed) futex2_wake on futex: %p\n", futex);
+ res = futex2_wake(shm, 1, FUTEX_32 | FUTEX_SHARED_FLAG);
+ if (res != 1) {
+ ksft_test_result_fail("futex2_wake shared (file backed) returned: %d %s\n",
+ errno, strerror(errno));
+ ret = RET_FAIL;
+ } else {
+ ksft_test_result_pass("futex2_wake shared (file backed)\n");
+ }
+
+ /* Freeing resources */
+ shmdt(shared_data);
+ munmap(shm, sizeof(f_private));
+ remove(SHM_PATH);
+
+ ksft_print_cnts();
+ return ret;
+}
diff --git a/tools/testing/selftests/futex/functional/run.sh b/tools/testing/selftests/futex/functional/run.sh
index 1acb6ace1680..3730159c865a 100755
--- a/tools/testing/selftests/futex/functional/run.sh
+++ b/tools/testing/selftests/futex/functional/run.sh
@@ -73,3 +73,6 @@ echo
echo
./futex_wait_uninitialized_heap $COLOR
./futex_wait_private_mapped_file $COLOR
+
+echo
+./futex2_wait $COLOR
diff --git a/tools/testing/selftests/futex/include/futex2test.h b/tools/testing/selftests/futex/include/futex2test.h
new file mode 100644
index 000000000000..e724d56b917e
--- /dev/null
+++ b/tools/testing/selftests/futex/include/futex2test.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/******************************************************************************
+ *
+ * Copyright Collabora Ltd., 2021
+ *
+ * DESCRIPTION
+ * Futex2 library addons for old futex library
+ *
+ * AUTHOR
+ * André Almeida <andrealmeid@collabora.com>
+ *
+ * HISTORY
+ * 2021-Feb-5: Initial version by André <andrealmeid@collabora.com>
+ *
+ *****************************************************************************/
+#include "futextest.h"
+#include <stdio.h>
+
+#define NSEC_PER_SEC 1000000000L
+
+#ifndef FUTEX_8
+# define FUTEX_8 0
+#endif
+#ifndef FUTEX_16
+# define FUTEX_16 1
+#endif
+#ifndef FUTEX_32
+# define FUTEX_32 2
+#endif
+
+/*
+ * - Y2038 section for 32-bit applications -
+ *
+ * Remove this when glibc is ready for y2038. Then, always compile with
+ * `-DTIME_BITS=64` or `-D__USE_TIME_BITS64`. glibc will provide both
+ * timespec64 and clock_gettime64 so we won't need to define here.
+ */
+#if defined(__i386__) || __TIMESIZE == 32
+# define NR_gettime __NR_clock_gettime64
+#else
+# define NR_gettime __NR_clock_gettime
+#endif
+
+struct timespec64 {
+ long long tv_sec; /* seconds */
+ long long tv_nsec; /* nanoseconds */
+};
+
+int gettime64(clock_t clockid, struct timespec64 *tv)
+{
+ return syscall(NR_gettime, clockid, tv);
+}
+/*
+ * - End of Y2038 section -
+ */
+
+/**
+ * futex2_wait - If (*uaddr == val), wait at uaddr until timo
+ * @uaddr: User address to wait on
+ * @val: Expected value at uaddr, return if is not equal
+ * @flags: Operation flags
+ * @timo: Optional timeout for operation
+ */
+static inline int futex2_wait(volatile void *uaddr, unsigned long val,
+ unsigned long flags, struct timespec64 *timo)
+{
+ return syscall(__NR_futex_wait, uaddr, val, flags, timo);
+}
+
+/**
+ * futex2_wake - Wake a number of waiters at uaddr
+ * @uaddr: Address to wake
+ * @nr: Number of waiters to wake
+ * @flags: Operation flags
+ */
+static inline int futex2_wake(volatile void *uaddr, unsigned int nr, unsigned long flags)
+{
+ return syscall(__NR_futex_wake, uaddr, nr, flags);
+}
--
2.31.1