[PATCH v2 2/4] selftests/resctrl: Add helpers for the non-contiguous test

[Maciej Wieczor-Retman]

The CAT non-contiguous selftests have to read the file responsible for
reporting support of non-contiguous CBMs in Intel CAT. Then the test
compares if that information matches what is reported by CPUID output.

Add a generic helper function to read a chosen functionality support
information.

Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@xxxxxxxxx>
---
Changelog v2:
- Added this patch.

 tools/testing/selftests/resctrl/resctrl.h   |  1 +
 tools/testing/selftests/resctrl/resctrlfs.c | 25 +++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
index 739e16d08a7b..8f72d94b9cbe 100644
--- a/tools/testing/selftests/resctrl/resctrl.h
+++ b/tools/testing/selftests/resctrl/resctrl.h
@@ -161,6 +161,7 @@ unsigned int count_contiguous_bits(unsigned long val, unsigned int *start);
 int get_full_cbm(const char *cache_type, unsigned long *mask);
 int get_mask_no_shareable(const char *cache_type, unsigned long *mask);
 int get_cache_size(int cpu_no, const char *cache_type, unsigned long *cache_size);
+int read_info_res_file(const char *resource, const char *filename);
 void ctrlc_handler(int signum, siginfo_t *info, void *ptr);
 int signal_handler_register(void);
 void signal_handler_unregister(void);
diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index 0e97036a64b8..70333440ff2f 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -249,6 +249,31 @@ static int get_bit_mask(const char *filename, unsigned long *mask)
 	return 0;
 }
 
+int read_info_res_file(const char *resource, const char *filename)
+{
+	char file_path[PATH_MAX];
+	FILE *fp;
+	int ret;
+
+	snprintf(file_path, sizeof(file_path), "%s/%s/%s", INFO_PATH, resource,
+		 filename);
+
+	fp = fopen(file_path, "r");
+	if (!fp) {
+		perror("Error in opening sparse_masks file\n");
+		return -1;
+	}
+
+	if (fscanf(fp, "%u", &ret) <= 0) {
+		perror("Could not get sparse_masks contents\n");
+		fclose(fp);
+		return -1;
+	}
+
+	fclose(fp);
+	return ret;
+}
+
 /*
  * create_bit_mask- Create bit mask from start, len pair
  * @start:	LSB of the mask
-- 
2.43.0