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 privileged and the kernel emulates them
12  * for us. Instructions using problem state SPR can be executed
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