Merge tag 'linux_kselftest-next-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kselftest update from Shuah Khan:
 "timer test:
   - remove duplicate defines
   - fixes to improve error reporting

  rtc test:
   - check rtc alarm status in alarm test

  resctrl test:
   - add array overrun checks during iMC config parsing code and when
     reading strings
   - fixes and reorganizing code"

* tag 'linux_kselftest-next-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (23 commits)
  selftests/resctrl: Replace magic constants used as array size
  selftests/resctrl: Keep results from first test run
  selftests/resctrl: Do not compare performance counters and resctrl at low bandwidth
  selftests/resctrl: Use cache size to determine "fill_buf" buffer size
  selftests/resctrl: Ensure measurements skip initialization of default benchmark
  selftests/resctrl: Make benchmark parameter passing robust
  selftests/resctrl: Remove unused measurement code
  selftests/resctrl: Only support measured read operation
  selftests/resctrl: Remove "once" parameter required to be false
  selftests/resctrl: Make wraparound handling obvious
  selftests/resctrl: Protect against array overflow when reading strings
  selftests/resctrl: Protect against array overrun during iMC config parsing
  selftests/resctrl: Fix memory overflow due to unhandled wraparound
  selftests/resctrl: Print accurate buffer size as part of MBM results
  selftests/resctrl: Make functions only used in same file static
  selftests: Add a test mangling with uc_sigmask
  selftests: Rename sigaltstack to generic signal
  selftest: rtc: Add to check rtc alarm status for alarm related test
  selftests:timers: remove local CLOCKID defines
  selftests: timers: Remove unneeded semicolon
  ...

Author: torvalds

Documentation/dev-tools/kselftest.rst

@@ -31,6 +31,15 @@ kselftest runs as a userspace process.  Tests that can be written/run in
 userspace may wish to use the `Test Harness`_.  Tests that need to be
 run in kernel space may wish to use a `Test Module`_.
 
+Documentation on the tests
+==========================
+
+For documentation on the kselftests themselves, see:
+
+.. toctree::
+
+   testing-devices
+
 Running the selftests (hotplug tests are run in limited mode)
 =============================================================
 

Documentation/dev-tools/testing-devices.rst

@@ -0,0 +1,47 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. Copyright (c) 2024 Collabora Ltd
+
+=============================
+Device testing with kselftest
+=============================
+
+
+There are a few different kselftests available for testing devices generically,
+with some overlap in coverage and different requirements. This document aims to
+give an overview of each one.
+
+Note: Paths in this document are relative to the kselftest folder
+(``tools/testing/selftests``).
+
+Device oriented kselftests:
+
+* Devicetree (``dt``)
+
+  * **Coverage**: Probe status for devices described in Devicetree
+  * **Requirements**: None
+
+* Error logs (``devices/error_logs``)
+
+  * **Coverage**: Error (or more critical) log messages presence coming from any
+    device
+  * **Requirements**: None
+
+* Discoverable bus (``devices/probe``)
+
+  * **Coverage**: Presence and probe status of USB or PCI devices that have been
+    described in the reference file
+  * **Requirements**: Manually describe the devices that should be tested in a
+    YAML reference file (see ``devices/probe/boards/google,spherion.yaml`` for
+    an example)
+
+* Exist (``devices/exist``)
+
+  * **Coverage**: Presence of all devices
+  * **Requirements**: Generate the reference (see ``devices/exist/README.rst``
+    for details) on a known-good kernel
+
+Therefore, the suggestion is to enable the error log and devicetree tests on all
+(DT-based) platforms, since they don't have any requirements. Then to greatly
+improve coverage, generate the reference for each platform and enable the exist
+test. The discoverable bus test can be used to verify the probe status of
+specific USB or PCI devices, but is probably not worth it for most cases.

tools/testing/selftests/Makefile

@@ -91,7 +91,7 @@ TARGETS += rust
 TARGETS += sched_ext
 TARGETS += seccomp
 TARGETS += sgx
-TARGETS += sigaltstack
+TARGETS += signal
 TARGETS += size
 TARGETS += sparc64
 TARGETS += splice

tools/testing/selftests/resctrl/cmt_test.c

@@ -99,14 +99,13 @@ static int check_results(struct resctrl_val_param *param, size_t span, int no_of
 		}
 
 		/* Field 3 is llc occ resc value */
-		if (runs > 0)
-			sum_llc_occu_resc += strtoul(token_array[3], NULL, 0);
+		sum_llc_occu_resc += strtoul(token_array[3], NULL, 0);
 		runs++;
 	}
 	fclose(fp);
 
 	return show_results_info(sum_llc_occu_resc, no_of_bits, span,
-				 MAX_DIFF, MAX_DIFF_PERCENT, runs - 1, true);
+				 MAX_DIFF, MAX_DIFF_PERCENT, runs, true);
 }
 
 static void cmt_test_cleanup(void)
@@ -116,15 +115,13 @@ static void cmt_test_cleanup(void)
 
 static int cmt_run_test(const struct resctrl_test *test, const struct user_params *uparams)
 {
-	const char * const *cmd = uparams->benchmark_cmd;
-	const char *new_cmd[BENCHMARK_ARGS];
+	struct fill_buf_param fill_buf = {};
 	unsigned long cache_total_size = 0;
 	int n = uparams->bits ? : 5;
 	unsigned long long_mask;
-	char *span_str = NULL;
 	int count_of_bits;
 	size_t span;
-	int ret, i;
+	int ret;
 
 	ret = get_full_cbm("L3", &long_mask);
 	if (ret)
@@ -155,32 +152,26 @@ static int cmt_run_test(const struct resctrl_test *test, const struct user_param
 
 	span = cache_portion_size(cache_total_size, param.mask, long_mask);
 
-	if (strcmp(cmd[0], "fill_buf") == 0) {
-		/* Duplicate the command to be able to replace span in it */
-		for (i = 0; uparams->benchmark_cmd[i]; i++)
-			new_cmd[i] = uparams->benchmark_cmd[i];
-		new_cmd[i] = NULL;
-
-		ret = asprintf(&span_str, "%zu", span);
-		if (ret < 0)
-			return -1;
-		new_cmd[1] = span_str;
-		cmd = new_cmd;
+	if (uparams->fill_buf) {
+		fill_buf.buf_size = span;
+		fill_buf.memflush = uparams->fill_buf->memflush;
+		param.fill_buf = &fill_buf;
+	} else if (!uparams->benchmark_cmd[0]) {
+		fill_buf.buf_size = span;
+		fill_buf.memflush = true;
+		param.fill_buf = &fill_buf;
 	}
 
 	remove(RESULT_FILE_NAME);
 
-	ret = resctrl_val(test, uparams, cmd, &param);
+	ret = resctrl_val(test, uparams, &param);
 	if (ret)
-		goto out;
+		return ret;
 
 	ret = check_results(&param, span, n);
 	if (ret && (get_vendor() == ARCH_INTEL))
 		ksft_print_msg("Intel CMT may be inaccurate when Sub-NUMA Clustering is enabled. Check BIOS configuration.\n");
 
-out:
-	free(span_str);
-
 	return ret;
 }
 

tools/testing/selftests/resctrl/fill_buf.c

@@ -88,18 +88,6 @@ static int fill_one_span_read(unsigned char *buf, size_t buf_size)
 	return sum;
 }
 
-static void fill_one_span_write(unsigned char *buf, size_t buf_size)
-{
-	unsigned char *end_ptr = buf + buf_size;
-	unsigned char *p;
-
-	p = buf;
-	while (p < end_ptr) {
-		*p = '1';
-		p += (CL_SIZE / 2);
-	}
-}
-
 void fill_cache_read(unsigned char *buf, size_t buf_size, bool once)
 {
 	int ret = 0;
@@ -114,20 +102,11 @@ void fill_cache_read(unsigned char *buf, size_t buf_size, bool once)
 	*value_sink = ret;
 }
 
-static void fill_cache_write(unsigned char *buf, size_t buf_size, bool once)
-{
-	while (1) {
-		fill_one_span_write(buf, buf_size);
-		if (once)
-			break;
-	}
-}
-
-unsigned char *alloc_buffer(size_t buf_size, int memflush)
+unsigned char *alloc_buffer(size_t buf_size, bool memflush)
 {
 	void *buf = NULL;
 	uint64_t *p64;
-	size_t s64;
+	ssize_t s64;
 	int ret;
 
 	ret = posix_memalign(&buf, PAGE_SIZE, buf_size);
@@ -151,19 +130,15 @@ unsigned char *alloc_buffer(size_t buf_size, int memflush)
 	return buf;
 }
 
-int run_fill_buf(size_t buf_size, int memflush, int op, bool once)
+ssize_t get_fill_buf_size(int cpu_no, const char *cache_type)
 {
-	unsigned char *buf;
-
-	buf = alloc_buffer(buf_size, memflush);
-	if (!buf)
-		return -1;
+	unsigned long cache_total_size = 0;
+	int ret;
 
-	if (op == 0)
-		fill_cache_read(buf, buf_size, once);
-	else
-		fill_cache_write(buf, buf_size, once);
-	free(buf);
+	ret = get_cache_size(cpu_no, cache_type, &cache_total_size);
+	if (ret)
+		return ret;
 
-	return 0;
+	return cache_total_size * 2 > MINIMUM_SPAN ?
+			cache_total_size * 2 : MINIMUM_SPAN;
 }

tools/testing/selftests/resctrl/mba_test.c

@@ -21,7 +21,7 @@ static int mba_init(const struct resctrl_val_param *param, int domain_id)
 {
 	int ret;
 
-	ret = initialize_mem_bw_imc();
+	ret = initialize_read_mem_bw_imc();
 	if (ret)
 		return ret;
 
@@ -39,7 +39,8 @@ static int mba_setup(const struct resctrl_test *test,
 		     const struct user_params *uparams,
 		     struct resctrl_val_param *p)
 {
-	static int runs_per_allocation, allocation = 100;
+	static unsigned int allocation = ALLOCATION_MIN;
+	static int runs_per_allocation;
 	char allocation_str[64];
 	int ret;
 
@@ -50,7 +51,7 @@ static int mba_setup(const struct resctrl_test *test,
 	if (runs_per_allocation++ != 0)
 		return 0;
 
-	if (allocation < ALLOCATION_MIN || allocation > ALLOCATION_MAX)
+	if (allocation > ALLOCATION_MAX)
 		return END_OF_TESTS;
 
 	sprintf(allocation_str, "%d", allocation);
@@ -59,21 +60,22 @@ static int mba_setup(const struct resctrl_test *test,
 	if (ret < 0)
 		return ret;
 
-	allocation -= ALLOCATION_STEP;
+	allocation += ALLOCATION_STEP;
 
 	return 0;
 }
 
 static int mba_measure(const struct user_params *uparams,
 		       struct resctrl_val_param *param, pid_t bm_pid)
 {
-	return measure_mem_bw(uparams, param, bm_pid, "reads");
+	return measure_read_mem_bw(uparams, param, bm_pid);
 }
 
 static bool show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc)
 {
-	int allocation, runs;
+	unsigned int allocation;
 	bool ret = false;
+	int runs;
 
 	ksft_print_msg("Results are displayed in (MB)\n");
 	/* Memory bandwidth from 100% down to 10% */
@@ -84,26 +86,29 @@ static bool show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc)
 		int avg_diff_per;
 		float avg_diff;
 
-		/*
-		 * The first run is discarded due to inaccurate value from
-		 * phase transition.
-		 */
-		for (runs = NUM_OF_RUNS * allocation + 1;
+		for (runs = NUM_OF_RUNS * allocation;
 		     runs < NUM_OF_RUNS * allocation + NUM_OF_RUNS ; runs++) {
 			sum_bw_imc += bw_imc[runs];
 			sum_bw_resc += bw_resc[runs];
 		}
 
-		avg_bw_imc = sum_bw_imc / (NUM_OF_RUNS - 1);
-		avg_bw_resc = sum_bw_resc / (NUM_OF_RUNS - 1);
+		avg_bw_imc = sum_bw_imc / NUM_OF_RUNS;
+		avg_bw_resc = sum_bw_resc / NUM_OF_RUNS;
+		if (avg_bw_imc < THROTTLE_THRESHOLD || avg_bw_resc < THROTTLE_THRESHOLD) {
+			ksft_print_msg("Bandwidth below threshold (%d MiB). Dropping results from MBA schemata %u.\n",
+				       THROTTLE_THRESHOLD,
+				       ALLOCATION_MIN + ALLOCATION_STEP * allocation);
+			continue;
+		}
+
 		avg_diff = (float)labs(avg_bw_resc - avg_bw_imc) / avg_bw_imc;
 		avg_diff_per = (int)(avg_diff * 100);
 
 		ksft_print_msg("%s Check MBA diff within %d%% for schemata %u\n",
 			       avg_diff_per > MAX_DIFF_PERCENT ?
 			       "Fail:" : "Pass:",
 			       MAX_DIFF_PERCENT,
-			       ALLOCATION_MAX - ALLOCATION_STEP * allocation);
+			       ALLOCATION_MIN + ALLOCATION_STEP * allocation);
 
 		ksft_print_msg("avg_diff_per: %d%%\n", avg_diff_per);
 		ksft_print_msg("avg_bw_imc: %lu\n", avg_bw_imc);
@@ -122,8 +127,9 @@ static bool show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc)
 
 static int check_results(void)
 {
+	unsigned long bw_resc[NUM_OF_RUNS * ALLOCATION_MAX / ALLOCATION_STEP];
+	unsigned long bw_imc[NUM_OF_RUNS * ALLOCATION_MAX / ALLOCATION_STEP];
 	char *token_array[8], output[] = RESULT_FILE_NAME, temp[512];
-	unsigned long bw_imc[1024], bw_resc[1024];
 	int runs;
 	FILE *fp;
 
@@ -170,11 +176,27 @@ static int mba_run_test(const struct resctrl_test *test, const struct user_param
 		.setup		= mba_setup,
 		.measure	= mba_measure,
 	};
+	struct fill_buf_param fill_buf = {};
 	int ret;
 
 	remove(RESULT_FILE_NAME);
 
-	ret = resctrl_val(test, uparams, uparams->benchmark_cmd, &param);
+	if (uparams->fill_buf) {
+		fill_buf.buf_size = uparams->fill_buf->buf_size;
+		fill_buf.memflush = uparams->fill_buf->memflush;
+		param.fill_buf = &fill_buf;
+	} else if (!uparams->benchmark_cmd[0]) {
+		ssize_t buf_size;
+
+		buf_size = get_fill_buf_size(uparams->cpu, "L3");
+		if (buf_size < 0)
+			return buf_size;
+		fill_buf.buf_size = buf_size;
+		fill_buf.memflush = true;
+		param.fill_buf = &fill_buf;
+	}
+
+	ret = resctrl_val(test, uparams, &param);
 	if (ret)
 		return ret;