selftests/powerpc: Add test for system wide DSCR default

export CFLAGS

SUB_DIRS = pmu copyloops mm tm primitives stringloops vphn switch_endian

SUB_DIRS = pmu copyloops mm tm primitives stringloops vphn switch_endian dscr

endif

TEST_PROGS := dscr_default_test

dscr_default_test: LDLIBS += -lpthread

all: $(TEST_PROGS)

$(TEST_PROGS): ../harness.c

include ../../lib.mk

clean:

	rm -f $(TEST_PROGS) *.o

/*

 * POWER Data Stream Control Register (DSCR)

 *

 * This header file contains helper functions and macros

 * required for all the DSCR related test cases.

 *

 * Copyright 2012, Anton Blanchard, IBM Corporation.

 * 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.

 */

#ifndef _SELFTESTS_POWERPC_DSCR_DSCR_H

#define _SELFTESTS_POWERPC_DSCR_DSCR_H

#include <unistd.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <fcntl.h>

#include <dirent.h>

#include <pthread.h>

#include <sched.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <sys/wait.h>

#include "utils.h"

#define SPRN_DSCR	0x11	/* Privilege state SPR */

#define SPRN_DSCR_USR	0x03	/* Problem state SPR */

#define THREADS		100	/* Max threads */

#define COUNT		100	/* Max iterations */

#define DSCR_MAX	16	/* Max DSCR value */

#define LEN_MAX		100	/* Max name length */

#define DSCR_DEFAULT	"/sys/devices/system/cpu/dscr_default"

#define CPU_PATH	"/sys/devices/system/cpu/"

#define rmb()  asm volatile("lwsync":::"memory")

#define wmb()  asm volatile("lwsync":::"memory")

#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))

/* Prilvilege state DSCR access */

inline unsigned long get_dscr(void)

{

	unsigned long ret;

	asm volatile("mfspr %0,%1" : "=r" (ret): "i" (SPRN_DSCR));

	return ret;

}

inline void set_dscr(unsigned long val)

{

	asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));

}

/* Problem state DSCR access */

inline unsigned long get_dscr_usr(void)

{

	unsigned long ret;

	asm volatile("mfspr %0,%1" : "=r" (ret): "i" (SPRN_DSCR_USR));

	return ret;

}

inline void set_dscr_usr(unsigned long val)

{

	asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR_USR));

}

/* Default DSCR access */

unsigned long get_default_dscr(void)

{

	int fd = -1, ret;

	char buf[16];

	unsigned long val;

	if (fd == -1) {

		fd = open(DSCR_DEFAULT, O_RDONLY);

		if (fd == -1) {

			perror("open() failed");

			exit(1);

		}

	}

	memset(buf, 0, sizeof(buf));

	lseek(fd, 0, SEEK_SET);

	ret = read(fd, buf, sizeof(buf));

	if (ret == -1) {

		perror("read() failed");

		exit(1);

	}

	sscanf(buf, "%lx", &val);

	close(fd);

	return val;

}

void set_default_dscr(unsigned long val)

{

	int fd = -1, ret;

	char buf[16];

	if (fd == -1) {

		fd = open(DSCR_DEFAULT, O_RDWR);

		if (fd == -1) {

			perror("open() failed");

			exit(1);

		}

	}

	sprintf(buf, "%lx\n", val);

	ret = write(fd, buf, strlen(buf));

	if (ret == -1) {

		perror("write() failed");

		exit(1);

	}

	close(fd);

}

double uniform_deviate(int seed)

{

	return seed * (1.0 / (RAND_MAX + 1.0));

}

#endif	/* _SELFTESTS_POWERPC_DSCR_DSCR_H */

/*

 * POWER Data Stream Control Register (DSCR) default test

 *

 * This test modifies the system wide default DSCR through

 * it's sysfs interface and then verifies that all threads

 * see the correct changed DSCR value immediately.

 *

 * Copyright 2012, Anton Blanchard, IBM Corporation.

 * 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.

 */

#include "dscr.h"

static unsigned long dscr;		/* System DSCR default */

static unsigned long sequence;

static unsigned long result[THREADS];

static void *do_test(void *in)

{

	unsigned long thread = (unsigned long)in;

	unsigned long i;

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

		unsigned long d, cur_dscr, cur_dscr_usr;

		unsigned long s1, s2;

		s1 = ACCESS_ONCE(sequence);

		if (s1 & 1)

			continue;

		rmb();

		d = dscr;

		cur_dscr = get_dscr();

		cur_dscr_usr = get_dscr_usr();

		rmb();

		s2 = sequence;

		if (s1 != s2)

			continue;

		if (cur_dscr != d) {

			fprintf(stderr, "thread %ld kernel DSCR should be %ld "

				"but is %ld\n", thread, d, cur_dscr);

			result[thread] = 1;

			pthread_exit(&result[thread]);

		}

		if (cur_dscr_usr != d) {

			fprintf(stderr, "thread %ld user DSCR should be %ld "

				"but is %ld\n", thread, d, cur_dscr_usr);

			result[thread] = 1;

			pthread_exit(&result[thread]);

		}

	}

	result[thread] = 0;

	pthread_exit(&result[thread]);

}

int dscr_default(void)

{

	pthread_t threads[THREADS];

	unsigned long i, *status[THREADS];

	unsigned long orig_dscr_default;

	orig_dscr_default = get_default_dscr();

	/* Initial DSCR default */

	dscr = 1;

	set_default_dscr(dscr);

	/* Spawn all testing threads */

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

		if (pthread_create(&threads[i], NULL, do_test, (void *)i)) {

			perror("pthread_create() failed");

			goto fail;

		}

	}

	srand(getpid());

	/* Keep changing the DSCR default */

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

		double ret = uniform_deviate(rand());

		if (ret < 0.0001) {

			sequence++;

			wmb();

			dscr++;

			if (dscr > DSCR_MAX)

				dscr = 0;

			set_default_dscr(dscr);

			wmb();

			sequence++;

		}

	}

	/* Individual testing thread exit status */

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

		if (pthread_join(threads[i], (void **)&(status[i]))) {

			perror("pthread_join() failed");

			goto fail;

		}

		if (*status[i]) {

			printf("%ldth thread failed to join with %ld status\n",

								i, *status[i]);

			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_default, "dscr_default_test");

}