1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * POWER Data Stream Control Register (DSCR) fork exec test |
4 | * |
5 | * This testcase modifies the DSCR using mtspr, forks & execs and |
6 | * verifies that the child is using the changed DSCR using mfspr. |
7 | * |
8 | * When using the privilege state SPR, the instructions such as |
9 | * mfspr or mtspr are privileged and the kernel emulates them |
10 | * for us. Instructions using problem state SPR can be executed |
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 | #include "dscr.h" |
18 | |
19 | static char *prog; |
20 | |
21 | static void do_exec(unsigned long parent_dscr) |
22 | { |
23 | unsigned long cur_dscr, cur_dscr_usr; |
24 | |
25 | cur_dscr = get_dscr(); |
26 | cur_dscr_usr = get_dscr_usr(); |
27 | |
28 | if (cur_dscr != parent_dscr) { |
29 | fprintf(stderr, "Parent DSCR %ld was not inherited " |
30 | "over exec (kernel value)\n" , parent_dscr); |
31 | exit(1); |
32 | } |
33 | |
34 | if (cur_dscr_usr != parent_dscr) { |
35 | fprintf(stderr, "Parent DSCR %ld was not inherited " |
36 | "over exec (user value)\n" , parent_dscr); |
37 | exit(1); |
38 | } |
39 | exit(0); |
40 | } |
41 | |
42 | int dscr_inherit_exec(void) |
43 | { |
44 | unsigned long i, dscr = 0; |
45 | pid_t pid; |
46 | |
47 | SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR)); |
48 | |
49 | for (i = 0; i < COUNT; i++) { |
50 | dscr++; |
51 | if (dscr > DSCR_MAX) |
52 | dscr = 0; |
53 | |
54 | if (dscr == get_default_dscr()) |
55 | continue; |
56 | |
57 | if (i % 2 == 0) |
58 | set_dscr_usr(dscr); |
59 | else |
60 | set_dscr(dscr); |
61 | |
62 | pid = fork(); |
63 | if (pid == -1) { |
64 | perror("fork() failed" ); |
65 | exit(1); |
66 | } else if (pid) { |
67 | int status; |
68 | |
69 | if (waitpid(pid, &status, 0) == -1) { |
70 | perror("waitpid() failed" ); |
71 | exit(1); |
72 | } |
73 | |
74 | if (!WIFEXITED(status)) { |
75 | fprintf(stderr, "Child didn't exit cleanly\n" ); |
76 | exit(1); |
77 | } |
78 | |
79 | if (WEXITSTATUS(status) != 0) { |
80 | fprintf(stderr, "Child didn't exit cleanly\n" ); |
81 | return 1; |
82 | } |
83 | } else { |
84 | char dscr_str[16]; |
85 | |
86 | sprintf(dscr_str, "%ld" , dscr); |
87 | execlp(prog, prog, "exec" , dscr_str, NULL); |
88 | exit(1); |
89 | } |
90 | } |
91 | return 0; |
92 | } |
93 | |
94 | int main(int argc, char *argv[]) |
95 | { |
96 | if (argc == 3 && !strcmp(argv[1], "exec" )) { |
97 | unsigned long parent_dscr; |
98 | |
99 | parent_dscr = atoi(argv[2]); |
100 | do_exec(parent_dscr); |
101 | } else if (argc != 1) { |
102 | fprintf(stderr, "Usage: %s\n" , argv[0]); |
103 | exit(1); |
104 | } |
105 | |
106 | prog = argv[0]; |
107 | return test_harness(dscr_inherit_exec, "dscr_inherit_exec_test" ); |
108 | } |
109 | |