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 } 110