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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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.
*/
#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 = READ_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");
}
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