1 /*
2 * Nios II Semihosting syscall interface.
3 * This code is derived from m68k-semi.c.
4 * The semihosting protocol implemented here is described in the
5 * libgloss sources:
6 * https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=blob;f=libgloss/nios2/nios2-semi.txt;hb=HEAD
7 *
8 * Copyright (c) 2017-2019 Mentor Graphics
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, see <http://www.gnu.org/licenses/>.
22 */
23
24 #include "qemu/osdep.h"
25 #include "cpu.h"
26 #include "gdbstub/syscalls.h"
27 #include "gdbstub/helpers.h"
28 #include "semihosting/syscalls.h"
29 #include "semihosting/uaccess.h"
30 #include "qemu/log.h"
31
32 #define HOSTED_EXIT 0
33 #define HOSTED_INIT_SIM 1
34 #define HOSTED_OPEN 2
35 #define HOSTED_CLOSE 3
36 #define HOSTED_READ 4
37 #define HOSTED_WRITE 5
38 #define HOSTED_LSEEK 6
39 #define HOSTED_RENAME 7
40 #define HOSTED_UNLINK 8
41 #define HOSTED_STAT 9
42 #define HOSTED_FSTAT 10
43 #define HOSTED_GETTIMEOFDAY 11
44 #define HOSTED_ISATTY 12
45 #define HOSTED_SYSTEM 13
46
host_to_gdb_errno(int err)47 static int host_to_gdb_errno(int err)
48 {
49 #define E(X) case E##X: return GDB_E##X
50 switch (err) {
51 E(PERM);
52 E(NOENT);
53 E(INTR);
54 E(BADF);
55 E(ACCES);
56 E(FAULT);
57 E(BUSY);
58 E(EXIST);
59 E(NODEV);
60 E(NOTDIR);
61 E(ISDIR);
62 E(INVAL);
63 E(NFILE);
64 E(MFILE);
65 E(FBIG);
66 E(NOSPC);
67 E(SPIPE);
68 E(ROFS);
69 E(NAMETOOLONG);
70 default:
71 return GDB_EUNKNOWN;
72 }
73 #undef E
74 }
75
nios2_semi_u32_cb(CPUState * cs,uint64_t ret,int err)76 static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
77 {
78 Nios2CPU *cpu = NIOS2_CPU(cs);
79 CPUNios2State *env = &cpu->env;
80 target_ulong args = env->regs[R_ARG1];
81
82 if (put_user_u32(ret, args) ||
83 put_user_u32(host_to_gdb_errno(err), args + 4)) {
84 /*
85 * The nios2 semihosting ABI does not provide any way to report this
86 * error to the guest, so the best we can do is log it in qemu.
87 * It is always a guest error not to pass us a valid argument block.
88 */
89 qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
90 "discarded because argument block not writable\n");
91 }
92 }
93
nios2_semi_u64_cb(CPUState * cs,uint64_t ret,int err)94 static void nios2_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
95 {
96 Nios2CPU *cpu = NIOS2_CPU(cs);
97 CPUNios2State *env = &cpu->env;
98 target_ulong args = env->regs[R_ARG1];
99
100 if (put_user_u32(ret >> 32, args) ||
101 put_user_u32(ret, args + 4) ||
102 put_user_u32(host_to_gdb_errno(err), args + 8)) {
103 /* No way to report this via nios2 semihosting ABI; just log it */
104 qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
105 "discarded because argument block not writable\n");
106 }
107 }
108
109 /*
110 * Read the input value from the argument block; fail the semihosting
111 * call if the memory read fails.
112 */
113 #define GET_ARG(n) do { \
114 if (get_user_ual(arg ## n, args + (n) * 4)) { \
115 goto failed; \
116 } \
117 } while (0)
118
119 #define GET_ARG64(n) do { \
120 if (get_user_ual(arg ## n, args + (n) * 4)) { \
121 goto failed64; \
122 } \
123 } while (0)
124
do_nios2_semihosting(CPUNios2State * env)125 void do_nios2_semihosting(CPUNios2State *env)
126 {
127 CPUState *cs = env_cpu(env);
128 int nr;
129 uint32_t args;
130 target_ulong arg0, arg1, arg2, arg3;
131
132 nr = env->regs[R_ARG0];
133 args = env->regs[R_ARG1];
134 switch (nr) {
135 case HOSTED_EXIT:
136 gdb_exit(env->regs[R_ARG1]);
137 exit(env->regs[R_ARG1]);
138
139 case HOSTED_OPEN:
140 GET_ARG(0);
141 GET_ARG(1);
142 GET_ARG(2);
143 GET_ARG(3);
144 semihost_sys_open(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
145 break;
146
147 case HOSTED_CLOSE:
148 GET_ARG(0);
149 semihost_sys_close(cs, nios2_semi_u32_cb, arg0);
150 break;
151
152 case HOSTED_READ:
153 GET_ARG(0);
154 GET_ARG(1);
155 GET_ARG(2);
156 semihost_sys_read(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
157 break;
158
159 case HOSTED_WRITE:
160 GET_ARG(0);
161 GET_ARG(1);
162 GET_ARG(2);
163 semihost_sys_write(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
164 break;
165
166 case HOSTED_LSEEK:
167 GET_ARG64(0);
168 GET_ARG64(1);
169 GET_ARG64(2);
170 GET_ARG64(3);
171 semihost_sys_lseek(cs, nios2_semi_u64_cb, arg0,
172 deposit64(arg2, 32, 32, arg1), arg3);
173 break;
174
175 case HOSTED_RENAME:
176 GET_ARG(0);
177 GET_ARG(1);
178 GET_ARG(2);
179 GET_ARG(3);
180 semihost_sys_rename(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
181 break;
182
183 case HOSTED_UNLINK:
184 GET_ARG(0);
185 GET_ARG(1);
186 semihost_sys_remove(cs, nios2_semi_u32_cb, arg0, arg1);
187 break;
188
189 case HOSTED_STAT:
190 GET_ARG(0);
191 GET_ARG(1);
192 GET_ARG(2);
193 semihost_sys_stat(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
194 break;
195
196 case HOSTED_FSTAT:
197 GET_ARG(0);
198 GET_ARG(1);
199 semihost_sys_fstat(cs, nios2_semi_u32_cb, arg0, arg1);
200 break;
201
202 case HOSTED_GETTIMEOFDAY:
203 GET_ARG(0);
204 GET_ARG(1);
205 semihost_sys_gettimeofday(cs, nios2_semi_u32_cb, arg0, arg1);
206 break;
207
208 case HOSTED_ISATTY:
209 GET_ARG(0);
210 semihost_sys_isatty(cs, nios2_semi_u32_cb, arg0);
211 break;
212
213 case HOSTED_SYSTEM:
214 GET_ARG(0);
215 GET_ARG(1);
216 semihost_sys_system(cs, nios2_semi_u32_cb, arg0, arg1);
217 break;
218
219 default:
220 qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
221 "semihosting syscall %d\n", nr);
222 nios2_semi_u32_cb(cs, -1, ENOSYS);
223 break;
224
225 failed:
226 nios2_semi_u32_cb(cs, -1, EFAULT);
227 break;
228 failed64:
229 nios2_semi_u64_cb(cs, -1, EFAULT);
230 break;
231 }
232 }
233