xref: /openbmc/qemu/tests/tcg/hexagon/overflow.c (revision 4921d0a7)
1 /*
2  *  Copyright(c) 2021-2023 Qualcomm Innovation Center, Inc. All Rights Reserved.
3  *
4  *  This program is free software; you can redistribute it and/or modify
5  *  it under the terms of the GNU General Public License as published by
6  *  the Free Software Foundation; either version 2 of the License, or
7  *  (at your option) any later version.
8  *
9  *  This program is distributed in the hope that it will be useful,
10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  *  GNU General Public License for more details.
13  *
14  *  You should have received a copy of the GNU General Public License
15  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #include <stdlib.h>
19 #include <stdio.h>
20 #include <stdint.h>
21 #include <unistd.h>
22 #include <sys/types.h>
23 #include <fcntl.h>
24 #include <setjmp.h>
25 #include <signal.h>
26 
27 int err;
28 
29 #include "hex_test.h"
30 
31 static int32_t satub(int32_t src, int32_t *p, bool *ovf_result)
32 {
33     int32_t result;
34     uint32_t usr;
35 
36     /*
37      * This instruction can set bit 0 (OVF/overflow) in usr
38      * Clear the bit first, then return that bit to the caller
39      *
40      * We also store the src into *p in the same packet, so we
41      * can ensure the overflow doesn't get set when an exception
42      * is generated.
43      */
44     asm volatile("r2 = usr\n\t"
45                  "r2 = clrbit(r2, #0)\n\t"        /* clear overflow bit */
46                  "usr = r2\n\t"
47                  "{\n\t"
48                  "    %0 = satub(%2)\n\t"
49                  "    memw(%3) = %2\n\t"
50                  "}\n\t"
51                  "%1 = usr\n\t"
52                  : "=r"(result), "=r"(usr)
53                  : "r"(src), "r"(p)
54                  : "r2", "usr", "memory");
55   *ovf_result = (usr & 1);
56   return result;
57 }
58 
59 bool read_usr_overflow(void)
60 {
61     uint32_t usr;
62     asm volatile("%0 = usr\n\t" : "=r"(usr));
63     return usr & 1;
64 }
65 
66 bool get_usr_overflow(uint32_t usr)
67 {
68     return usr & 1;
69 }
70 
71 bool get_usr_fp_invalid(uint32_t usr)
72 {
73     return (usr >> 1) & 1;
74 }
75 
76 int32_t get_usr_lpcfg(uint32_t usr)
77 {
78     return (usr >> 8) & 0x3;
79 }
80 
81 jmp_buf jmp_env;
82 bool usr_overflow;
83 
84 static void sig_segv(int sig, siginfo_t *info, void *puc)
85 {
86     usr_overflow = read_usr_overflow();
87     longjmp(jmp_env, 1);
88 }
89 
90 static void test_packet(void)
91 {
92     int32_t convres;
93     int32_t satres;
94     uint32_t usr;
95 
96     asm("r2 = usr\n\t"
97         "r2 = clrbit(r2, #0)\n\t"        /* clear overflow bit */
98         "r2 = clrbit(r2, #1)\n\t"        /* clear FP invalid bit */
99         "usr = r2\n\t"
100         "{\n\t"
101         "    %0 = convert_sf2uw(%3):chop\n\t"
102         "    %1 = satb(%4)\n\t"
103         "}\n\t"
104         "%2 = usr\n\t"
105         : "=r"(convres), "=r"(satres), "=r"(usr)
106         : "r"(0x6a051b86), "r"(0x0410eec0)
107         : "r2", "usr");
108 
109     check32(convres, 0xffffffff);
110     check32(satres, 0x7f);
111     check32(get_usr_overflow(usr), true);
112     check32(get_usr_fp_invalid(usr), true);
113 
114     asm("r2 = usr\n\t"
115         "r2 = clrbit(r2, #0)\n\t"        /* clear overflow bit */
116         "usr = r2\n\t"
117         "%2 = r2\n\t"
118         "p3 = sp3loop0(1f, #1)\n\t"
119         "1:\n\t"
120         "{\n\t"
121         "    %0 = satb(%2)\n\t"
122         "}:endloop0\n\t"
123         "%1 = usr\n\t"
124         : "=r"(satres), "=r"(usr)
125         : "r"(0x0410eec0)
126         : "r2", "usr", "p3", "sa0", "lc0");
127 
128     check32(satres, 0x7f);
129     check32(get_usr_overflow(usr), true);
130     check32(get_usr_lpcfg(usr), 2);
131 }
132 
133 int main()
134 {
135     struct sigaction act;
136     bool ovf;
137 
138     /* SIGSEGV test */
139     act.sa_sigaction = sig_segv;
140     sigemptyset(&act.sa_mask);
141     act.sa_flags = SA_SIGINFO;
142     sigaction(SIGSEGV, &act, NULL);
143     if (setjmp(jmp_env) == 0) {
144         satub(300, 0, &ovf);
145     }
146 
147     act.sa_handler = SIG_DFL;
148     sigemptyset(&act.sa_mask);
149     act.sa_flags = 0;
150 
151     check32(usr_overflow, false);
152 
153     test_packet();
154 
155     puts(err ? "FAIL" : "PASS");
156     return err ? EXIT_FAILURE : EXIT_SUCCESS;
157 }
158