selftests/powerpc: Add thread based stress test for DSCR sysfs interfaces

TEST_PROGS := dscr_default_test dscr_explicit_test dscr_user_test	\

	      dscr_inherit_test dscr_inherit_exec_test dscr_sysfs_test

	      dscr_inherit_test dscr_inherit_exec_test dscr_sysfs_test	\

	      dscr_sysfs_thread_test

dscr_default_test: LDLIBS += -lpthread

/*

 * POWER Data Stream Control Register (DSCR) sysfs thread test

 *

 * This test updates the system wide DSCR default value through

 * sysfs interface which should then update all the CPU specific

 * DSCR default values which must also be then visible to threads

 * executing on individual CPUs on the system.

 *

 * Copyright 2015, Anshuman Khandual, IBM Corporation.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 as published

 * by the Free Software Foundation.

 */

#define _GNU_SOURCE

#include "dscr.h"

static int test_thread_dscr(unsigned long val)

{

	unsigned long cur_dscr, cur_dscr_usr;

	cur_dscr = get_dscr();

	cur_dscr_usr = get_dscr_usr();

	if (val != cur_dscr) {

		printf("[cpu %d] Kernel DSCR should be %ld but is %ld\n",

					sched_getcpu(), val, cur_dscr);

		return 1;

	}

	if (val != cur_dscr_usr) {

		printf("[cpu %d] User DSCR should be %ld but is %ld\n",

					sched_getcpu(), val, cur_dscr_usr);

		return 1;

	}

	return 0;

}

static int check_cpu_dscr_thread(unsigned long val)

{

	cpu_set_t mask;

	int cpu;

	for (cpu = 0; cpu < CPU_SETSIZE; cpu++) {

		CPU_ZERO(&mask);

		CPU_SET(cpu, &mask);

		if (sched_setaffinity(0, sizeof(mask), &mask))

			continue;

		if (test_thread_dscr(val))

			return 1;

	}

	return 0;

}

int dscr_sysfs_thread(void)

{

	unsigned long orig_dscr_default;

	int i, j;

	orig_dscr_default = get_default_dscr();

	for (i = 0; i < COUNT; i++) {

		for (j = 0; j < DSCR_MAX; j++) {

			set_default_dscr(j);

			if (check_cpu_dscr_thread(j))

				goto fail;

		}

	}

	set_default_dscr(orig_dscr_default);

	return 0;

fail:

	set_default_dscr(orig_dscr_default);

	return 1;

}

int main(int argc, char *argv[])

{

	return test_harness(dscr_sysfs_thread, "dscr_sysfs_thread_test");

}