[PATCH v4 3/3] kselftest: Extend vDSO selftest to clock_getres

[Vincenzo Frascino]

The current version of the multiarch vDSO selftest verifies only
gettimeofday.

Extend the vDSO selftest to clock_getres, to verify that the
syscall and the vDSO library function return the same information.

The extension has been used to verify the hrtimer_resoltion fix.

Cc: Shuah Khan <shuah at kernel.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino at arm.com>
---

Note: This patch is independent from the others in this series, hence it
can be merged singularly by the kselftest maintainers.

 tools/testing/selftests/vDSO/Makefile         |   2 +
 .../selftests/vDSO/vdso_clock_getres.c        | 124 ++++++++++++++++++
 2 files changed, 126 insertions(+)
 create mode 100644 tools/testing/selftests/vDSO/vdso_clock_getres.c

diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index 9e03d61f52fd..d5c5bfdf1ac1 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -5,6 +5,7 @@ uname_M := $(shell uname -m 2>/dev/null || echo not)
 ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
 
 TEST_GEN_PROGS := $(OUTPUT)/vdso_test
+TEST_GEN_PROGS += $(OUTPUT)/vdso_clock_getres
 ifeq ($(ARCH),x86)
 TEST_GEN_PROGS += $(OUTPUT)/vdso_standalone_test_x86
 endif
@@ -18,6 +19,7 @@ endif
 
 all: $(TEST_GEN_PROGS)
 $(OUTPUT)/vdso_test: parse_vdso.c vdso_test.c
+$(OUTPUT)/vdso_clock_getres: vdso_clock_getres.c
 $(OUTPUT)/vdso_standalone_test_x86: vdso_standalone_test_x86.c parse_vdso.c
 	$(CC) $(CFLAGS) $(CFLAGS_vdso_standalone_test_x86) \
 		vdso_standalone_test_x86.c parse_vdso.c \
diff --git a/tools/testing/selftests/vDSO/vdso_clock_getres.c b/tools/testing/selftests/vDSO/vdso_clock_getres.c
new file mode 100644
index 000000000000..b62d8d4f7c38
--- /dev/null
+++ b/tools/testing/selftests/vDSO/vdso_clock_getres.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
+/*
+ * vdso_clock_getres.c: Sample code to test clock_getres.
+ * Copyright (c) 2019 Arm Ltd.
+ *
+ * Compile with:
+ * gcc -std=gnu99 vdso_clock_getres.c
+ *
+ * Tested on ARM, ARM64, MIPS32, x86 (32-bit and 64-bit),
+ * Power (32-bit and 64-bit), S390x (32-bit and 64-bit).
+ * Might work on other architectures.
+ */
+
+#define _GNU_SOURCE
+#include <elf.h>
+#include <err.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/auxv.h>
+#include <sys/mman.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#include "../kselftest.h"
+
+static long syscall_clock_getres(clockid_t _clkid, struct timespec *_ts)
+{
+	long ret;
+
+	ret = syscall(SYS_clock_getres, _clkid, _ts);
+
+	return ret;
+}
+
+const char *vdso_clock_name[12] = {
+	"CLOCK_REALTIME",
+	"CLOCK_MONOTONIC",
+	"CLOCK_PROCESS_CPUTIME_ID",
+	"CLOCK_THREAD_CPUTIME_ID",
+	"CLOCK_MONOTONIC_RAW",
+	"CLOCK_REALTIME_COARSE",
+	"CLOCK_MONOTONIC_COARSE",
+	"CLOCK_BOOTTIME",
+	"CLOCK_REALTIME_ALARM",
+	"CLOCK_BOOTTIME_ALARM",
+	"CLOCK_SGI_CYCLE",
+	"CLOCK_TAI",
+};
+
+/*
+ * This function calls clock_getres in vdso and by system call
+ * with different values for clock_id.
+ *
+ * Example of output:
+ *
+ * clock_id: CLOCK_REALTIME [PASS]
+ * clock_id: CLOCK_BOOTTIME [PASS]
+ * clock_id: CLOCK_TAI [PASS]
+ * clock_id: CLOCK_REALTIME_COARSE [PASS]
+ * clock_id: CLOCK_MONOTONIC [PASS]
+ * clock_id: CLOCK_MONOTONIC_RAW [PASS]
+ * clock_id: CLOCK_MONOTONIC_COARSE [PASS]
+ */
+static inline int vdso_test_clock(unsigned int clock_id)
+{
+	struct timespec x, y;
+
+	printf("clock_id: %s", vdso_clock_name[clock_id]);
+	clock_getres(clock_id, &x);
+	syscall_clock_getres(clock_id, &y);
+
+	if ((x.tv_sec != y.tv_sec) || (x.tv_sec != y.tv_sec)) {
+		printf(" [FAIL]\n");
+		return KSFT_FAIL;
+	}
+
+	printf(" [PASS]\n");
+	return KSFT_PASS;
+}
+
+int main(int argc, char **argv)
+{
+	int ret;
+
+#if _POSIX_TIMERS > 0
+
+#ifdef CLOCK_REALTIME
+	ret = vdso_test_clock(CLOCK_REALTIME);
+#endif
+
+#ifdef CLOCK_BOOTTIME
+	ret += vdso_test_clock(CLOCK_BOOTTIME);
+#endif
+
+#ifdef CLOCK_TAI
+	ret += vdso_test_clock(CLOCK_TAI);
+#endif
+
+#ifdef CLOCK_REALTIME_COARSE
+	ret += vdso_test_clock(CLOCK_REALTIME_COARSE);
+#endif
+
+#ifdef CLOCK_MONOTONIC
+	ret += vdso_test_clock(CLOCK_MONOTONIC);
+#endif
+
+#ifdef CLOCK_MONOTONIC_RAW
+	ret += vdso_test_clock(CLOCK_MONOTONIC_RAW);
+#endif
+
+#ifdef CLOCK_MONOTONIC_COARSE
+	ret += vdso_test_clock(CLOCK_MONOTONIC_COARSE);
+#endif
+
+#endif
+	if (ret > 0)
+		return KSFT_FAIL;
+
+	return KSFT_PASS;
+}
-- 
2.21.0