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 
23 int 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 
68 int main(int argc, char *argv[])
69 {
70 	return test_harness(dscr_explicit, "dscr_explicit_test");
71 }
72