[LTP] [PATCH v1 07/31] testcases: sysfs: Add sys_cpu_topology02

[Cyril Hrubis]

A test for /sys/devices/system/cpu/cpu*/topology/* files.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
---
 runtest/sysfs                                 |  1 +
 .../sysfs/devices/system/cpu/.gitignore       |  1 +
 .../devices/system/cpu/sys_cpu_topology02.c   | 98 +++++++++++++++++++
 3 files changed, 100 insertions(+)
 create mode 100644 testcases/kernel/sysfs/devices/system/cpu/sys_cpu_topology02.c

diff --git a/runtest/sysfs b/runtest/sysfs
index 4fc8f1eb2..b1daab68f 100644
--- a/runtest/sysfs
+++ b/runtest/sysfs
@@ -3,3 +3,4 @@ sys_kernel01 sys_kernel01
 sys_clocksource01 sys_clocksource01
 sys_node01 sys_node01
 sys_cpu_topology01 sys_cpu_topology01
+sys_cpu_topology02 sys_cpu_topology02
diff --git a/testcases/kernel/sysfs/devices/system/cpu/.gitignore b/testcases/kernel/sysfs/devices/system/cpu/.gitignore
index 0615aff77..a688a9b50 100644
--- a/testcases/kernel/sysfs/devices/system/cpu/.gitignore
+++ b/testcases/kernel/sysfs/devices/system/cpu/.gitignore
@@ -1 +1,2 @@
 /sys_cpu_topology01
+/sys_cpu_topology02
diff --git a/testcases/kernel/sysfs/devices/system/cpu/sys_cpu_topology02.c b/testcases/kernel/sysfs/devices/system/cpu/sys_cpu_topology02.c
new file mode 100644
index 000000000..00f7c6af9
--- /dev/null
+++ b/testcases/kernel/sysfs/devices/system/cpu/sys_cpu_topology02.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Cyril Hrubis <chrubis@suse.cz>
+ */
+
+/*\
+ * Sanity checks for the per-CPU topology attributes exported under
+ * /sys/devices/system/cpu/cpuN/topology/.
+ *
+ * The topology masks describe how a CPU relates to the others. They are nested
+ * from the smallest (SMT threads) to the largest (package) group, so for every
+ * online CPU the test verifies that:
+ *
+ * - thread_siblings_list is a subset of core_cpus_list
+ * - core_cpus_list is a subset of package_cpus_list
+ * - package_cpus_list is a subset of the online CPUs
+ * - the CPU itself is contained in its own thread_siblings_list
+ * - core_id and physical_package_id are in [0, highest possible CPU id],
+ *   since there can be at most as many cores/packages as possible CPUs
+ *   (every core has at least one thread, every package at least one core)
+ *
+ * All checks skip gracefully with TCONF when a particular attribute is not
+ * present, as the exact set of topology files differs between kernel versions
+ * and architectures.
+ */
+
+#include <stdio.h>
+#include <limits.h>
+#include <unistd.h>
+#include "tst_test.h"
+#include "tst_sysfs_assert.h"
+
+#define SYS_CPU "/sys/devices/system/cpu"
+
+static void check_self_in_threads(int cpu)
+{
+	TST_SYSFS_ASSERT_LIST_CONTAINS(cpu,
+		SYS_CPU "/cpu%d/topology/thread_siblings_list", cpu);
+}
+
+static void check_cpu_topology(int cpu, int poss_max_id)
+{
+	char sub[PATH_MAX], super[PATH_MAX];
+
+	if (access(SYS_CPU, F_OK))
+		return;
+
+	if (!tst_sysfs_exists(SYS_CPU "/cpu%d/topology/core_id", cpu)) {
+		tst_res(TCONF, "cpu%d has no topology directory", cpu);
+		return;
+	}
+
+	tst_res(TINFO, "Checking cpu%d topology", cpu);
+
+	TST_SYSFS_ASSERT_RANGELL(0, poss_max_id,
+			       SYS_CPU "/cpu%d/topology/core_id", cpu);
+
+	TST_SYSFS_ASSERT_RANGELL(0, poss_max_id,
+			       SYS_CPU "/cpu%d/topology/physical_package_id",
+			       cpu);
+
+	snprintf(sub, sizeof(sub),
+		 SYS_CPU "/cpu%d/topology/thread_siblings_list", cpu);
+	snprintf(super, sizeof(super),
+		 SYS_CPU "/cpu%d/topology/core_cpus_list", cpu);
+	TST_SYSFS_ASSERT_LIST_SUBSET(sub, super);
+
+	snprintf(sub, sizeof(sub),
+		 SYS_CPU "/cpu%d/topology/core_cpus_list", cpu);
+	snprintf(super, sizeof(super),
+		 SYS_CPU "/cpu%d/topology/package_cpus_list", cpu);
+	TST_SYSFS_ASSERT_LIST_SUBSET(sub, super);
+
+	snprintf(sub, sizeof(sub),
+		 SYS_CPU "/cpu%d/topology/package_cpus_list", cpu);
+	TST_SYSFS_ASSERT_LIST_SUBSET(sub, SYS_CPU "/online");
+
+	check_self_in_threads(cpu);
+}
+
+static void do_test(void)
+{
+	int count, max_id, poss_count, poss_max_id, cpu;
+
+	if (TST_SYSFS_ASSERT_PARSE_LIST(&count, &max_id, SYS_CPU "/online"))
+		return;
+
+	if (TST_SYSFS_ASSERT_PARSE_LIST(&poss_count, &poss_max_id,
+					SYS_CPU "/possible"))
+		return;
+
+	for (cpu = 0; cpu <= max_id; cpu++)
+		check_cpu_topology(cpu, poss_max_id);
+}
+
+static struct tst_test test = {
+	.test_all = do_test,
+};
-- 
2.54.0