1 /* 2 * POWER Data Stream Control Register (DSCR) fork test 3 * 4 * This testcase modifies the DSCR using mtspr, forks and then 5 * verifies that the child process has the correct changed DSCR 6 * value using mfspr. 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 23 int dscr_inherit(void) 24 { 25 unsigned long i, dscr = 0; 26 pid_t pid; 27 28 srand(getpid()); 29 set_dscr(dscr); 30 31 for (i = 0; i < COUNT; i++) { 32 unsigned long cur_dscr, cur_dscr_usr; 33 34 dscr++; 35 if (dscr > DSCR_MAX) 36 dscr = 0; 37 38 if (i % 2 == 0) 39 set_dscr_usr(dscr); 40 else 41 set_dscr(dscr); 42 43 pid = fork(); 44 if (pid == -1) { 45 perror("fork() failed"); 46 exit(1); 47 } else if (pid) { 48 int status; 49 50 if (waitpid(pid, &status, 0) == -1) { 51 perror("waitpid() failed"); 52 exit(1); 53 } 54 55 if (!WIFEXITED(status)) { 56 fprintf(stderr, "Child didn't exit cleanly\n"); 57 exit(1); 58 } 59 60 if (WEXITSTATUS(status) != 0) { 61 fprintf(stderr, "Child didn't exit cleanly\n"); 62 return 1; 63 } 64 } else { 65 cur_dscr = get_dscr(); 66 if (cur_dscr != dscr) { 67 fprintf(stderr, "Kernel DSCR should be %ld " 68 "but is %ld\n", dscr, cur_dscr); 69 exit(1); 70 } 71 72 cur_dscr_usr = get_dscr_usr(); 73 if (cur_dscr_usr != dscr) { 74 fprintf(stderr, "User DSCR should be %ld " 75 "but is %ld\n", dscr, cur_dscr_usr); 76 exit(1); 77 } 78 exit(0); 79 } 80 } 81 return 0; 82 } 83 84 int main(int argc, char *argv[]) 85 { 86 return test_harness(dscr_inherit, "dscr_inherit_test"); 87 } 88
