--- /dev/null
+/*
+ * Copyright 2015, Cyril Bur, IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include "../basic_asm.h"
+#include "../vsx_asm.h"
+
+#long check_vsx(vector int *r3);
+#This function wraps storeing VSX regs to the end of an array and a
+#call to a comparison function in C which boils down to a memcmp()
+FUNC_START(check_vsx)
+ PUSH_BASIC_STACK(32)
+ std r3,STACK_FRAME_PARAM(0)(sp)
+ addi r3, r3, 16 * 12 #Second half of array
+ bl store_vsx
+ ld r3,STACK_FRAME_PARAM(0)(sp)
+ bl vsx_memcmp
+ POP_BASIC_STACK(32)
+ blr
+FUNC_END(check_vsx)
+
+# int preempt_vmx(vector int *varray, int *threads_starting,
+# int *running);
+# On starting will (atomically) decrement threads_starting as a signal
+# that the VMX have been loaded with varray. Will proceed to check the
+# validity of the VMX registers while running is not zero.
+FUNC_START(preempt_vsx)
+ PUSH_BASIC_STACK(512)
+ std r3,STACK_FRAME_PARAM(0)(sp) # vector int *varray
+ std r4,STACK_FRAME_PARAM(1)(sp) # int *threads_starting
+ std r5,STACK_FRAME_PARAM(2)(sp) # int *running
+
+ bl load_vsx
+ nop
+
+ sync
+ # Atomic DEC
+ ld r3,STACK_FRAME_PARAM(1)(sp)
+1: lwarx r4,0,r3
+ addi r4,r4,-1
+ stwcx. r4,0,r3
+ bne- 1b
+
+2: ld r3,STACK_FRAME_PARAM(0)(sp)
+ bl check_vsx
+ nop
+ cmpdi r3,0
+ bne 3f
+ ld r4,STACK_FRAME_PARAM(2)(sp)
+ ld r5,0(r4)
+ cmpwi r5,0
+ bne 2b
+
+3: POP_BASIC_STACK(512)
+ blr
+FUNC_END(preempt_vsx)
--- /dev/null
+/*
+ * Copyright 2015, Cyril Bur, IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * This test attempts to see if the VSX registers change across preemption.
+ * There is no way to be sure preemption happened so this test just
+ * uses many threads and a long wait. As such, a successful test
+ * doesn't mean much but a failure is bad.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+#include "utils.h"
+
+/* Time to wait for workers to get preempted (seconds) */
+#define PREEMPT_TIME 20
+/*
+ * Factor by which to multiply number of online CPUs for total number of
+ * worker threads
+ */
+#define THREAD_FACTOR 8
+
+/*
+ * Ensure there is twice the number of non-volatile VMX regs!
+ * check_vmx() is going to use the other half as space to put the live
+ * registers before calling vsx_memcmp()
+ */
+__thread vector int varray[24] = {
+ {1, 2, 3, 4 }, {5, 6, 7, 8 }, {9, 10,11,12},
+ {13,14,15,16}, {17,18,19,20}, {21,22,23,24},
+ {25,26,27,28}, {29,30,31,32}, {33,34,35,36},
+ {37,38,39,40}, {41,42,43,44}, {45,46,47,48}
+};
+
+int threads_starting;
+int running;
+
+extern long preempt_vsx(vector int *varray, int *threads_starting, int *running);
+
+long vsx_memcmp(vector int *a) {
+ vector int zero = {0, 0, 0, 0};
+ int i;
+
+ FAIL_IF(a != varray);
+
+ for(i = 0; i < 12; i++) {
+ if (memcmp(&a[i + 12], &zero, sizeof(vector int)) == 0) {
+ fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12);
+ return 2;
+ }
+ }
+
+ if (memcmp(a, &a[12], 12 * sizeof(vector int))) {
+ long *p = (long *)a;
+ fprintf(stderr, "VSX mismatch\n");
+ for (i = 0; i < 24; i=i+2)
+ fprintf(stderr, "%d: 0x%08lx%08lx | 0x%08lx%08lx\n",
+ i/2 + i%2 + 20, p[i], p[i + 1], p[i + 24], p[i + 25]);
+ return 1;
+ }
+ return 0;
+}
+
+void *preempt_vsx_c(void *p)
+{
+ int i, j;
+ long rc;
+ srand(pthread_self());
+ for (i = 0; i < 12; i++)
+ for (j = 0; j < 4; j++) {
+ varray[i][j] = rand();
+ /* Don't want zero because it hides kernel problems */
+ if (varray[i][j] == 0)
+ j--;
+ }
+ rc = preempt_vsx(varray, &threads_starting, &running);
+ if (rc == 2)
+ fprintf(stderr, "Caught zeros in VSX compares\n");
+ return (void *)rc;
+}
+
+int test_preempt_vsx(void)
+{
+ int i, rc, threads;
+ pthread_t *tids;
+
+ threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
+ tids = malloc(threads * sizeof(pthread_t));
+ FAIL_IF(!tids);
+
+ running = true;
+ threads_starting = threads;
+ for (i = 0; i < threads; i++) {
+ rc = pthread_create(&tids[i], NULL, preempt_vsx_c, NULL);
+ FAIL_IF(rc);
+ }
+
+ setbuf(stdout, NULL);
+ /* Not really nessesary but nice to wait for every thread to start */
+ printf("\tWaiting for %d workers to start...", threads_starting);
+ while(threads_starting)
+ asm volatile("": : :"memory");
+ printf("done\n");
+
+ printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
+ sleep(PREEMPT_TIME);
+ printf("done\n");
+
+ printf("\tStopping workers...");
+ /*
+ * Working are checking this value every loop. In preempt_vsx 'cmpwi r5,0; bne 2b'.
+ * r5 will have loaded the value of running.
+ */
+ running = 0;
+ for (i = 0; i < threads; i++) {
+ void *rc_p;
+ pthread_join(tids[i], &rc_p);
+
+ /*
+ * Harness will say the fail was here, look at why preempt_vsx
+ * returned
+ */
+ if ((long) rc_p)
+ printf("oops\n");
+ FAIL_IF((long) rc_p);
+ }
+ printf("done\n");
+
+ return 0;
+}
+
+int main(int argc, char *argv[])
+{
+ return test_harness(test_preempt_vsx, "vsx_preempt");
+}
projects / linux-beck.git / commitdiff