test/stress/eattls.c

   1 /*
   2  * EATTLS.C
   3  *
   4  *      Rapidly switch between threads with different TLS pointers to
   5  *      test that the operating system properly switches the TLS segment.
   6  *
   7  * $DragonFly: src/test/stress/eattls.c,v 1.3 2007/04/13 12:12:27 corecode Exp $
   8  */
   9
  10 #include <sys/types.h>
  11 #include <sys/tls.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <unistd.h>
  15
  16 #define BIGSIZE (16 * 1024 * 1024)
  17
  18 struct test {
  19         int random1;
  20         int random2;
  21 };
  22
  23 static int getdata(int offset);
  24
  25 int
  26 main(int ac, char **av)
  27 {
  28     struct tls_info info;
  29     struct test *test;
  30     char *buf;
  31     int gs;
  32     int random1;
  33     int random2;
  34
  35     srandomdev();
  36     random1 = random();
  37     random2 = random();
  38
  39     buf = malloc(BIGSIZE);
  40     buf += random() % (BIGSIZE - sizeof(struct test));
  41     test = (void *)buf;
  42     info.base = buf;
  43     info.size = sizeof(struct test);
  44     if ((gs = set_tls_area(2, &info, sizeof(info))) < 0) {
  45         perror("set_tls_area");
  46         exit(1);
  47     }
  48     test->random1 = random1;
  49     test->random2 = random2;
  50     printf("setting %%gs to 0x%02x segment at %p\n", gs, test);
  51     __asm __volatile("mov %0,%%gs" : : "g" (gs));
  52     for (;;) {
  53         if (getdata(0) != random1 || getdata(4) != random2)
  54             printf("data verification failed!\n");
  55         if (random() % 1000 > 500)
  56             usleep(random() % 1000);
  57     }
  58
  59     return(0);
  60 }
  61
  62 static int
  63 getdata(int offset)
  64 {
  65     int rv;
  66     __asm __volatile("movl %%gs:(%0),%%eax; movl %%eax,%1" :
  67                      "+r" (offset) : "m" (rv) : "ax");
  68     return (rv);
  69 }
  70