1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * POWER Data Stream Control Register (DSCR) SPR test
4 *
5 * This test modifies the DSCR value through both the SPR number
6 * based mtspr instruction and then makes sure that the same is
7 * reflected through mfspr instruction using either of the SPR
8 * numbers.
9 *
10 * When using the privilege state SPR, the instructions such as
11 * mfspr or mtspr are priviledged and the kernel emulates them
12 * for us. Instructions using problem state SPR can be exuecuted
13 * directly without any emulation if the HW supports them. Else
14 * they also get emulated by the kernel.
15 *
16 * Copyright 2013, Anton Blanchard, IBM Corporation.
17 * Copyright 2015, Anshuman Khandual, IBM Corporation.
18 */
19 #include "dscr.h"
20
check_dscr(char * str)21 static int check_dscr(char *str)
22 {
23 unsigned long cur_dscr, cur_dscr_usr;
24
25 cur_dscr = get_dscr();
26 cur_dscr_usr = get_dscr_usr();
27 if (cur_dscr != cur_dscr_usr) {
28 printf("%s set, kernel get %lx != user get %lx\n",
29 str, cur_dscr, cur_dscr_usr);
30 return 1;
31 }
32 return 0;
33 }
34
dscr_user(void)35 int dscr_user(void)
36 {
37 int i;
38
39 SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
40
41 check_dscr("");
42
43 for (i = 0; i < COUNT; i++) {
44 set_dscr(i);
45 if (check_dscr("kernel"))
46 return 1;
47 }
48
49 for (i = 0; i < COUNT; i++) {
50 set_dscr_usr(i);
51 if (check_dscr("user"))
52 return 1;
53 }
54 return 0;
55 }
56
main(int argc,char * argv[])57 int main(int argc, char *argv[])
58 {
59 return test_harness(dscr_user, "dscr_user_test");
60 }
61