LXR linux/tools/testing/selftests/powerpc/dscr/dscr_explicit

   1/*
   2 * POWER Data Stream Control Register (DSCR) explicit test
   3 *
   4 * This test modifies the DSCR value using mtspr instruction and
   5 * verifies the change with mfspr instruction. It uses both the
   6 * privilege state SPR and the problem state SPR for this purpose.
   7 *
   8 * When using the privilege state SPR, the instructions such as
   9 * mfspr or mtspr are priviledged and the kernel emulates them
  10 * for us. Instructions using problem state SPR can be exuecuted
  11 * directly without any emulation if the HW supports them. Else
  12 * they also get emulated by the kernel.
  13 *
  14 * Copyright 2012, Anton Blanchard, IBM Corporation.
  15 * Copyright 2015, Anshuman Khandual, IBM Corporation.
  16 *
  17 * This program is free software; you can redistribute it and/or modify it
  18 * under the terms of the GNU General Public License version 2 as published
  19 * by the Free Software Foundation.
  20 */
  21#include "dscr.h"
  22
  23int dscr_explicit(void)
  24{
  25        unsigned long i, dscr = 0;
  26
  27        srand(getpid());
  28        set_dscr(dscr);
  29
  30        for (i = 0; i < COUNT; i++) {
  31                unsigned long cur_dscr, cur_dscr_usr;
  32                double ret = uniform_deviate(rand());
  33
  34                if (ret < 0.001) {
  35                        dscr++;
  36                        if (dscr > DSCR_MAX)
  37                                dscr = 0;
  38
  39                        set_dscr(dscr);
  40                }
  41
  42                cur_dscr = get_dscr();
  43                if (cur_dscr != dscr) {
  44                        fprintf(stderr, "Kernel DSCR should be %ld but "
  45                                        "is %ld\n", dscr, cur_dscr);
  46                        return 1;
  47                }
  48
  49                ret = uniform_deviate(rand());
  50                if (ret < 0.001) {
  51                        dscr++;
  52                        if (dscr > DSCR_MAX)
  53                                dscr = 0;
  54
  55                        set_dscr_usr(dscr);
  56                }
  57
  58                cur_dscr_usr = get_dscr_usr();
  59                if (cur_dscr_usr != dscr) {
  60                        fprintf(stderr, "User DSCR should be %ld but "
  61                                        "is %ld\n", dscr, cur_dscr_usr);
  62                        return 1;
  63                }
  64        }
  65        return 0;
  66}
  67
  68int main(int argc, char *argv[])
  69{
  70        return test_harness(dscr_explicit, "dscr_explicit_test");
  71}
  72