[LTP] [PATCH v3 10/31] testcases: sysfs: Add sys_cpu_cache01

[Cyril Hrubis]

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

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
---
 runtest/sysfs                                 |   1 +
 .../sysfs/devices/system/cpu/.gitignore       |   1 +
 .../devices/system/cpu/sys_cpu_cache01.c      | 108 ++++++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 testcases/kernel/sysfs/devices/system/cpu/sys_cpu_cache01.c

diff --git a/runtest/sysfs b/runtest/sysfs
index 4cc2360c6..928b85928 100644
--- a/runtest/sysfs
+++ b/runtest/sysfs
@@ -6,3 +6,4 @@ sys_cpu_topology01 sys_cpu_topology01
 sys_cpu_topology02 sys_cpu_topology02
 sys_cpu_vulnerabilities01 sys_cpu_vulnerabilities01
 sys_cpu_smt01 sys_cpu_smt01
+sys_cpu_cache01 sys_cpu_cache01
diff --git a/testcases/kernel/sysfs/devices/system/cpu/.gitignore b/testcases/kernel/sysfs/devices/system/cpu/.gitignore
index d0f8a6dab..8da0a61c0 100644
--- a/testcases/kernel/sysfs/devices/system/cpu/.gitignore
+++ b/testcases/kernel/sysfs/devices/system/cpu/.gitignore
@@ -2,3 +2,4 @@
 /sys_cpu_topology02
 /sys_cpu_vulnerabilities01
 /sys_cpu_smt01
+/sys_cpu_cache01
diff --git a/testcases/kernel/sysfs/devices/system/cpu/sys_cpu_cache01.c b/testcases/kernel/sysfs/devices/system/cpu/sys_cpu_cache01.c
new file mode 100644
index 000000000..91afa2b71
--- /dev/null
+++ b/testcases/kernel/sysfs/devices/system/cpu/sys_cpu_cache01.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Cyril Hrubis <chrubis@suse.cz>
+ */
+
+/*\
+ * Sanity checks for the CPU cache attributes exported under
+ * /sys/devices/system/cpu/cpuN/cache/indexM/.
+ *
+ * For every cache index of every online CPU the test verifies that:
+ *
+ * - level is greater than zero
+ * - type is one of Data, Instruction or Unified
+ * - coherency_line_size is a power of two
+ * - number_of_sets and ways_of_associativity are greater than zero
+ * - shared_cpu_list is a subset of the online CPUs
+ *
+ * All checks skip gracefully with TCONF when a particular attribute is not
+ * present.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <dirent.h>
+#include <limits.h>
+#include <unistd.h>
+#include "tst_test.h"
+#include "tst_sysfs_assert.h"
+
+#define SYS_CPU "/sys/devices/system/cpu"
+
+static const char *const type_allowed[] = {
+	"Data", "Instruction", "Unified", NULL
+};
+
+static void check_index(int cpu, const char *index)
+{
+	char shared_cpu_list[PATH_MAX];
+
+	tst_res(TINFO, "Checking cpu%d %s", cpu, index);
+
+	TST_SYSFS_ASSERT_RANGELL(1, LONG_MAX,
+			       SYS_CPU "/cpu%d/cache/%s/level", cpu, index);
+
+	TST_SYSFS_ASSERT_ONEOF(type_allowed,
+			       SYS_CPU "/cpu%d/cache/%s/type", cpu, index);
+
+	TST_SYSFS_ASSERT_POW2(SYS_CPU "/cpu%d/cache/%s/coherency_line_size",
+			      cpu, index);
+
+	TST_SYSFS_ASSERT_RANGELL(1, LONG_MAX,
+			       SYS_CPU "/cpu%d/cache/%s/number_of_sets",
+			       cpu, index);
+
+	TST_SYSFS_ASSERT_RANGELL(1, LONG_MAX,
+			       SYS_CPU "/cpu%d/cache/%s/ways_of_associativity",
+			       cpu, index);
+
+	snprintf(shared_cpu_list, sizeof(shared_cpu_list),
+		 SYS_CPU "/cpu%d/cache/%s/shared_cpu_list", cpu, index);
+	TST_SYSFS_ASSERT_LIST_SUBSET(shared_cpu_list, SYS_CPU "/online");
+}
+
+static int check_cpu_caches(int cpu)
+{
+	char cache_dir[PATH_MAX];
+	DIR *d;
+	struct dirent *ent;
+	int found = 0;
+
+	snprintf(cache_dir, sizeof(cache_dir), SYS_CPU "/cpu%d/cache", cpu);
+
+	if (access(cache_dir, F_OK))
+		return 0;
+
+	d = SAFE_OPENDIR(cache_dir);
+
+	while ((ent = SAFE_READDIR(d))) {
+		if (strncmp(ent->d_name, "index", 5))
+			continue;
+
+		found = 1;
+		check_index(cpu, ent->d_name);
+	}
+
+	SAFE_CLOSEDIR(d);
+
+	return found;
+}
+
+static void do_test(void)
+{
+	int count, max_id, cpu;
+	int found = 0;
+
+	if (TST_SYSFS_ASSERT_PARSE_LIST(&count, &max_id, SYS_CPU "/online"))
+		return;
+
+	for (cpu = 0; cpu <= max_id; cpu++)
+		found |= check_cpu_caches(cpu);
+
+	if (!found)
+		tst_res(TCONF, "No CPU cache info found");
+}
+
+static struct tst_test test = {
+	.test_all = do_test,
+};
-- 
2.51.0