tools/testing/selftests/powerpc/dscr/dscr_inherit_exec_test.c

   1 /*
   2  * POWER Data Stream Control Register (DSCR) fork exec test
   3  *
   4  * This testcase modifies the DSCR using mtspr, forks & execs and
   5  * verifies that the child is using the changed DSCR using mfspr.
   6  *
   7  * When using the privilege state SPR, the instructions such as
   8  * mfspr or mtspr are privileged and the kernel emulates them
   9  * for us. Instructions using problem state SPR can be executed
  10  * directly without any emulation if the HW supports them. Else
  11  * they also get emulated by the kernel.
  12  *
  13  * Copyright 2012, Anton Blanchard, IBM Corporation.
  14  * Copyright 2015, Anshuman Khandual, IBM Corporation.
  15  *
  16  * This program is free software; you can redistribute it and/or modify it
  17  * under the terms of the GNU General Public License version 2 as published
  18  * by the Free Software Foundation.
  19  */
  20 #include "dscr.h"
  21
  22 static char *prog;
  23
  24 static void do_exec(unsigned long parent_dscr)
  25 {
  26         unsigned long cur_dscr, cur_dscr_usr;
  27
  28         cur_dscr = get_dscr();
  29         cur_dscr_usr = get_dscr_usr();
  30
  31         if (cur_dscr != parent_dscr) {
  32                 fprintf(stderr, "Parent DSCR %ld was not inherited "
  33                                 "over exec (kernel value)\n", parent_dscr);
  34                 exit(1);
  35         }
  36
  37         if (cur_dscr_usr != parent_dscr) {
  38                 fprintf(stderr, "Parent DSCR %ld was not inherited "
  39                                 "over exec (user value)\n", parent_dscr);
  40                 exit(1);
  41         }
  42         exit(0);
  43 }
  44
  45 int dscr_inherit_exec(void)
  46 {
  47         unsigned long i, dscr = 0;
  48         pid_t pid;
  49
  50         for (i = 0; i < COUNT; i++) {
  51                 dscr++;
  52                 if (dscr > DSCR_MAX)
  53                         dscr = 0;
  54
  55                 if (dscr == get_default_dscr())
  56                         continue;
  57
  58                 if (i % 2 == 0)
  59                         set_dscr_usr(dscr);
  60                 else
  61                         set_dscr(dscr);
  62
  63                 pid = fork();
  64                 if (pid == -1) {
  65                         perror("fork() failed");
  66                         exit(1);
  67                 } else if (pid) {
  68                         int status;
  69
  70                         if (waitpid(pid, &status, 0) == -1) {
  71                                 perror("waitpid() failed");
  72                                 exit(1);
  73                         }
  74
  75                         if (!WIFEXITED(status)) {
  76                                 fprintf(stderr, "Child didn't exit cleanly\n");
  77                                 exit(1);
  78                         }
  79
  80                         if (WEXITSTATUS(status) != 0) {
  81                                 fprintf(stderr, "Child didn't exit cleanly\n");
  82                                 return 1;
  83                         }
  84                 } else {
  85                         char dscr_str[16];
  86
  87                         sprintf(dscr_str, "%ld", dscr);
  88                         execlp(prog, prog, "exec", dscr_str, NULL);
  89                         exit(1);
  90                 }
  91         }
  92         return 0;
  93 }
  94
  95 int main(int argc, char *argv[])
  96 {
  97         if (argc == 3 && !strcmp(argv[1], "exec")) {
  98                 unsigned long parent_dscr;
  99
 100                 parent_dscr = atoi(argv[2]);
 101                 do_exec(parent_dscr);
 102         } else if (argc != 1) {
 103                 fprintf(stderr, "Usage: %s\n", argv[0]);
 104                 exit(1);
 105         }
 106
 107         prog = argv[0];
 108         return test_harness(dscr_inherit_exec, "dscr_inherit_exec_test");
 109 }