[LTP] [PATCH v2] syscalls/prctl10: Add basic test for PR_SET/GET_TSC

[Yang Xu]

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
---
 include/lapi/prctl.h                       |   7 ++
 runtest/syscalls                           |   1 +
 testcases/kernel/syscalls/prctl/.gitignore |   1 +
 testcases/kernel/syscalls/prctl/prctl10.c  | 108 +++++++++++++++++++++
 4 files changed, 117 insertions(+)
 create mode 100644 testcases/kernel/syscalls/prctl/prctl10.c

diff --git a/include/lapi/prctl.h b/include/lapi/prctl.h
index fa5922231..8d3ef5c32 100644
--- a/include/lapi/prctl.h
+++ b/include/lapi/prctl.h
@@ -19,6 +19,13 @@
 # define PR_SET_SECCOMP  22
 #endif
 
+#ifndef PR_SET_TSC
+# define PR_GET_TSC 25
+# define PR_SET_TSC 26
+# define PR_TSC_ENABLE  1
+# define PR_TSC_SIGSEGV 2
+#endif
+
 #ifndef PR_SET_TIMERSLACK
 # define PR_SET_TIMERSLACK 29
 # define PR_GET_TIMERSLACK 30
diff --git a/runtest/syscalls b/runtest/syscalls
index 61a7b7677..51de0a614 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1004,6 +1004,7 @@ prctl06 prctl06
 prctl07 prctl07
 prctl08 prctl08
 prctl09 prctl09
+prctl10 prctl10
 
 pread01 pread01
 pread01_64 pread01_64
diff --git a/testcases/kernel/syscalls/prctl/.gitignore b/testcases/kernel/syscalls/prctl/.gitignore
index 0f2c9b194..50ee4bf60 100644
--- a/testcases/kernel/syscalls/prctl/.gitignore
+++ b/testcases/kernel/syscalls/prctl/.gitignore
@@ -8,3 +8,4 @@
 /prctl07
 /prctl08
 /prctl09
+/prctl10
diff --git a/testcases/kernel/syscalls/prctl/prctl10.c b/testcases/kernel/syscalls/prctl/prctl10.c
new file mode 100644
index 000000000..01307ecd7
--- /dev/null
+++ b/testcases/kernel/syscalls/prctl/prctl10.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022 FUJITSU LIMITED. All rights reserved.
+ * Author: Yang Xu <xuyang2018.jy@fujitsu.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Basic test to test behaviour of PR_GET_TSC and PR_SET_TSC.
+ *
+ * Set the state of the flag determining whether the timestamp counter can
+ * be read by the process.
+ *
+ * - Pass PR_TSC_ENABLE to arg2 to allow it to be read.
+ * - Pass PR_TSC_SIGSEGV to arg2 to generate a SIGSEGV when read.
+ */
+
+#include <sys/prctl.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "lapi/prctl.h"
+
+#define TCASE_ENTRY(tsc_read_stat) { .name = #tsc_read_stat, .read_stat = tsc_read_stat}
+
+static const char * const tsc_read_stat_names[] = {
+	[0] = "[not set]",
+	[PR_TSC_ENABLE] = "PR_TSC_ENABLE",
+	[PR_TSC_SIGSEGV] = "PR_TSC_SIGSEGV",
+};
+
+static struct tcase {
+	char *name;
+	int read_stat;
+} tcases[] = {
+	TCASE_ENTRY(PR_TSC_ENABLE),
+	TCASE_ENTRY(PR_TSC_SIGSEGV)
+};
+
+static uint64_t rdtsc(void)
+{
+	uint32_t lo, hi;
+	/* We cannot use "=A", since this would use %rax on x86_64 */
+	__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+	return (uint64_t)hi << 32 | lo;
+}
+
+
+static int expected_status(int status, int exp_status)
+{
+	if (!exp_status && WIFEXITED(status))
+		return 0;
+
+	if (exp_status && WIFSIGNALED(status) && WTERMSIG(status) == exp_status)
+		return 0;
+
+	return 1;
+}
+
+static void verify_prctl(unsigned int n)
+{
+	struct tcase *tc = &tcases[n];
+	unsigned long long time1, time2;
+	int tsc_val = 0, pid, status;
+
+	pid = SAFE_FORK();
+	if (!pid) {
+		TST_EXP_PASS_SILENT(prctl(PR_SET_TSC, tc->read_stat));
+		TST_EXP_PASS_SILENT(prctl(PR_GET_TSC, &tsc_val));
+		if (tsc_val == tc->read_stat)
+			tst_res(TPASS, "current state is %s(%d)",
+					tc->name, tc->read_stat);
+		else
+			tst_res(TFAIL, "current state is %s(%d), expect %s(%d)",
+					tsc_read_stat_names[tsc_val],
+					tsc_val, tc->name, tc->read_stat);
+
+		time1 = rdtsc();
+		time2 = rdtsc();
+		if (time2 > time1)
+			tst_res(TPASS, "rdtsc works correctly, %lld ->%lld",
+				time1, time2);
+		else
+			tst_res(TFAIL, "rdtsc works incorrectly, %lld ->%lld",
+				time1, time2);
+		exit(0);
+	}
+	SAFE_WAITPID(pid, &status, 0);
+
+	if (expected_status(status, tc->read_stat == PR_TSC_SIGSEGV ? SIGSEGV : 0))
+		tst_res(TFAIL, "Test %s failed", tc->name);
+	else
+		tst_res(TPASS, "Test %s succeeded", tc->name);
+}
+
+static struct tst_test test = {
+	.needs_root = 1,
+	.forks_child = 1,
+	.test = verify_prctl,
+	.tcnt = ARRAY_SIZE(tcases),
+	.supported_archs = (const char *const []) {
+		"x86",
+		"x86_64",
+		NULL
+	},
+};
-- 
2.27.0