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
26#include "cpu.h"
27#if defined(CONFIG_USER_ONLY)
28#include "qemu.h"
29#else
30#include "qemu-common.h"
31#include "exec/gdbstub.h"
32#include "exec/softmmu-semi.h"
33#endif
34#include "qemu/log.h"
35
36#define HOSTED_EXIT 0
37#define HOSTED_INIT_SIM 1
38#define HOSTED_OPEN 2
39#define HOSTED_CLOSE 3
40#define HOSTED_READ 4
41#define HOSTED_WRITE 5
42#define HOSTED_LSEEK 6
43#define HOSTED_RENAME 7
44#define HOSTED_UNLINK 8
45#define HOSTED_STAT 9
46#define HOSTED_FSTAT 10
47#define HOSTED_GETTIMEOFDAY 11
48#define HOSTED_ISATTY 12
49#define HOSTED_SYSTEM 13
50
51typedef uint32_t gdb_mode_t;
52typedef uint32_t gdb_time_t;
53
54struct nios2_gdb_stat {
55 uint32_t gdb_st_dev; /* device */
56 uint32_t gdb_st_ino; /* inode */
57 gdb_mode_t gdb_st_mode; /* protection */
58 uint32_t gdb_st_nlink; /* number of hard links */
59 uint32_t gdb_st_uid; /* user ID of owner */
60 uint32_t gdb_st_gid; /* group ID of owner */
61 uint32_t gdb_st_rdev; /* device type (if inode device) */
62 uint64_t gdb_st_size; /* total size, in bytes */
63 uint64_t gdb_st_blksize; /* blocksize for filesystem I/O */
64 uint64_t gdb_st_blocks; /* number of blocks allocated */
65 gdb_time_t gdb_st_atime; /* time of last access */
66 gdb_time_t gdb_st_mtime; /* time of last modification */
67 gdb_time_t gdb_st_ctime; /* time of last change */
68} QEMU_PACKED;
69
70struct gdb_timeval {
71 gdb_time_t tv_sec; /* second */
72 uint64_t tv_usec; /* microsecond */
73} QEMU_PACKED;
74
75#define GDB_O_RDONLY 0x0
76#define GDB_O_WRONLY 0x1
77#define GDB_O_RDWR 0x2
78#define GDB_O_APPEND 0x8
79#define GDB_O_CREAT 0x200
80#define GDB_O_TRUNC 0x400
81#define GDB_O_EXCL 0x800
82
83static int translate_openflags(int flags)
84{
85 int hf;
86
87 if (flags & GDB_O_WRONLY) {
88 hf = O_WRONLY;
89 } else if (flags & GDB_O_RDWR) {
90 hf = O_RDWR;
91 } else {
92 hf = O_RDONLY;
93 }
94
95 if (flags & GDB_O_APPEND) {
96 hf |= O_APPEND;
97 }
98 if (flags & GDB_O_CREAT) {
99 hf |= O_CREAT;
100 }
101 if (flags & GDB_O_TRUNC) {
102 hf |= O_TRUNC;
103 }
104 if (flags & GDB_O_EXCL) {
105 hf |= O_EXCL;
106 }
107
108 return hf;
109}
110
111static bool translate_stat(CPUNios2State *env, target_ulong addr,
112 struct stat *s)
113{
114 struct nios2_gdb_stat *p;
115
116 p = lock_user(VERIFY_WRITE, addr, sizeof(struct nios2_gdb_stat), 0);
117
118 if (!p) {
119 return false;
120 }
121 p->gdb_st_dev = cpu_to_be32(s->st_dev);
122 p->gdb_st_ino = cpu_to_be32(s->st_ino);
123 p->gdb_st_mode = cpu_to_be32(s->st_mode);
124 p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
125 p->gdb_st_uid = cpu_to_be32(s->st_uid);
126 p->gdb_st_gid = cpu_to_be32(s->st_gid);
127 p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
128 p->gdb_st_size = cpu_to_be64(s->st_size);
129#ifdef _WIN32
130 /* Windows stat is missing some fields. */
131 p->gdb_st_blksize = 0;
132 p->gdb_st_blocks = 0;
133#else
134 p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
135 p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
136#endif
137 p->gdb_st_atime = cpu_to_be32(s->st_atime);
138 p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
139 p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
140 unlock_user(p, addr, sizeof(struct nios2_gdb_stat));
141 return true;
142}
143
144static void nios2_semi_return_u32(CPUNios2State *env, uint32_t ret,
145 uint32_t err)
146{
147 target_ulong args = env->regs[R_ARG1];
148 if (put_user_u32(ret, args) ||
149 put_user_u32(err, args + 4)) {
150 /*
151 * The nios2 semihosting ABI does not provide any way to report this
152 * error to the guest, so the best we can do is log it in qemu.
153 * It is always a guest error not to pass us a valid argument block.
154 */
155 qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
156 "discarded because argument block not writable\n");
157 }
158}
159
160static void nios2_semi_return_u64(CPUNios2State *env, uint64_t ret,
161 uint32_t err)
162{
163 target_ulong args = env->regs[R_ARG1];
164 if (put_user_u32(ret >> 32, args) ||
165 put_user_u32(ret, args + 4) ||
166 put_user_u32(err, args + 8)) {
167 /* No way to report this via nios2 semihosting ABI; just log it */
168 qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
169 "discarded because argument block not writable\n");
170 }
171}
172
173static int nios2_semi_is_lseek;
174
175static void nios2_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
176{
177 Nios2CPU *cpu = NIOS2_CPU(cs);
178 CPUNios2State *env = &cpu->env;
179
180 if (nios2_semi_is_lseek) {
181 /*
182 * FIXME: We've already lost the high bits of the lseek
183 * return value.
184 */
185 nios2_semi_return_u64(env, ret, err);
186 nios2_semi_is_lseek = 0;
187 } else {
188 nios2_semi_return_u32(env, ret, err);
189 }
190}
191
192/*
193 * Read the input value from the argument block; fail the semihosting
194 * call if the memory read fails.
195 */
196#define GET_ARG(n) do { \
197 if (get_user_ual(arg ## n, args + (n) * 4)) { \
198 result = -1; \
199 errno = EFAULT; \
200 goto failed; \
201 } \
202} while (0)
203
204void do_nios2_semihosting(CPUNios2State *env)
205{
206 int nr;
207 uint32_t args;
208 target_ulong arg0, arg1, arg2, arg3;
209 void *p;
210 void *q;
211 uint32_t len;
212 uint32_t result;
213
214 nr = env->regs[R_ARG0];
215 args = env->regs[R_ARG1];
216 switch (nr) {
217 case HOSTED_EXIT:
218 gdb_exit(env, env->regs[R_ARG0]);
219 exit(env->regs[R_ARG0]);
220 case HOSTED_OPEN:
221 GET_ARG(0);
222 GET_ARG(1);
223 GET_ARG(2);
224 GET_ARG(3);
225 if (use_gdb_syscalls()) {
226 gdb_do_syscall(nios2_semi_cb, "open,%s,%x,%x", arg0, (int)arg1,
227 arg2, arg3);
228 return;
229 } else {
230 p = lock_user_string(arg0);
231 if (!p) {
232 result = -1;
233 errno = EFAULT;
234 } else {
235 result = open(p, translate_openflags(arg2), arg3);
236 unlock_user(p, arg0, 0);
237 }
238 }
239 break;
240 case HOSTED_CLOSE:
241 {
242 /* Ignore attempts to close stdin/out/err. */
243 GET_ARG(0);
244 int fd = arg0;
245 if (fd > 2) {
246 if (use_gdb_syscalls()) {
247 gdb_do_syscall(nios2_semi_cb, "close,%x", arg0);
248 return;
249 } else {
250 result = close(fd);
251 }
252 } else {
253 result = 0;
254 }
255 break;
256 }
257 case HOSTED_READ:
258 GET_ARG(0);
259 GET_ARG(1);
260 GET_ARG(2);
261 len = arg2;
262 if (use_gdb_syscalls()) {
263 gdb_do_syscall(nios2_semi_cb, "read,%x,%x,%x",
264 arg0, arg1, len);
265 return;
266 } else {
267 p = lock_user(VERIFY_WRITE, arg1, len, 0);
268 if (!p) {
269 result = -1;
270 errno = EFAULT;
271 } else {
272 result = read(arg0, p, len);
273 unlock_user(p, arg1, len);
274 }
275 }
276 break;
277 case HOSTED_WRITE:
278 GET_ARG(0);
279 GET_ARG(1);
280 GET_ARG(2);
281 len = arg2;
282 if (use_gdb_syscalls()) {
283 gdb_do_syscall(nios2_semi_cb, "write,%x,%x,%x",
284 arg0, arg1, len);
285 return;
286 } else {
287 p = lock_user(VERIFY_READ, arg1, len, 1);
288 if (!p) {
289 result = -1;
290 errno = EFAULT;
291 } else {
292 result = write(arg0, p, len);
293 unlock_user(p, arg0, 0);
294 }
295 }
296 break;
297 case HOSTED_LSEEK:
298 {
299 uint64_t off;
300 GET_ARG(0);
301 GET_ARG(1);
302 GET_ARG(2);
303 GET_ARG(3);
304 off = (uint32_t)arg2 | ((uint64_t)arg1 << 32);
305 if (use_gdb_syscalls()) {
306 nios2_semi_is_lseek = 1;
307 gdb_do_syscall(nios2_semi_cb, "lseek,%x,%lx,%x",
308 arg0, off, arg3);
309 } else {
310 off = lseek(arg0, off, arg3);
311 nios2_semi_return_u64(env, off, errno);
312 }
313 return;
314 }
315 case HOSTED_RENAME:
316 GET_ARG(0);
317 GET_ARG(1);
318 GET_ARG(2);
319 GET_ARG(3);
320 if (use_gdb_syscalls()) {
321 gdb_do_syscall(nios2_semi_cb, "rename,%s,%s",
322 arg0, (int)arg1, arg2, (int)arg3);
323 return;
324 } else {
325 p = lock_user_string(arg0);
326 q = lock_user_string(arg2);
327 if (!p || !q) {
328 result = -1;
329 errno = EFAULT;
330 } else {
331 result = rename(p, q);
332 }
333 unlock_user(p, arg0, 0);
334 unlock_user(q, arg2, 0);
335 }
336 break;
337 case HOSTED_UNLINK:
338 GET_ARG(0);
339 GET_ARG(1);
340 if (use_gdb_syscalls()) {
341 gdb_do_syscall(nios2_semi_cb, "unlink,%s",
342 arg0, (int)arg1);
343 return;
344 } else {
345 p = lock_user_string(arg0);
346 if (!p) {
347 result = -1;
348 errno = EFAULT;
349 } else {
350 result = unlink(p);
351 unlock_user(p, arg0, 0);
352 }
353 }
354 break;
355 case HOSTED_STAT:
356 GET_ARG(0);
357 GET_ARG(1);
358 GET_ARG(2);
359 if (use_gdb_syscalls()) {
360 gdb_do_syscall(nios2_semi_cb, "stat,%s,%x",
361 arg0, (int)arg1, arg2);
362 return;
363 } else {
364 struct stat s;
365 p = lock_user_string(arg0);
366 if (!p) {
367 result = -1;
368 errno = EFAULT;
369 } else {
370 result = stat(p, &s);
371 unlock_user(p, arg0, 0);
372 }
373 if (result == 0 && !translate_stat(env, arg2, &s)) {
374 result = -1;
375 errno = EFAULT;
376 }
377 }
378 break;
379 case HOSTED_FSTAT:
380 GET_ARG(0);
381 GET_ARG(1);
382 if (use_gdb_syscalls()) {
383 gdb_do_syscall(nios2_semi_cb, "fstat,%x,%x",
384 arg0, arg1);
385 return;
386 } else {
387 struct stat s;
388 result = fstat(arg0, &s);
389 if (result == 0 && !translate_stat(env, arg1, &s)) {
390 result = -1;
391 errno = EFAULT;
392 }
393 }
394 break;
395 case HOSTED_GETTIMEOFDAY:
396 /* Only the tv parameter is used. tz is assumed NULL. */
397 GET_ARG(0);
398 if (use_gdb_syscalls()) {
399 gdb_do_syscall(nios2_semi_cb, "gettimeofday,%x,%x",
400 arg0, 0);
401 return;
402 } else {
403 qemu_timeval tv;
404 struct gdb_timeval *p;
405 result = qemu_gettimeofday(&tv);
406 if (result != 0) {
407 p = lock_user(VERIFY_WRITE, arg0, sizeof(struct gdb_timeval),
408 0);
409 if (!p) {
410 result = -1;
411 errno = EFAULT;
412 } else {
413 p->tv_sec = cpu_to_be32(tv.tv_sec);
414 p->tv_usec = cpu_to_be64(tv.tv_usec);
415 unlock_user(p, arg0, sizeof(struct gdb_timeval));
416 }
417 }
418 }
419 break;
420 case HOSTED_ISATTY:
421 GET_ARG(0);
422 if (use_gdb_syscalls()) {
423 gdb_do_syscall(nios2_semi_cb, "isatty,%x", arg0);
424 return;
425 } else {
426 result = isatty(arg0);
427 }
428 break;
429 case HOSTED_SYSTEM:
430 GET_ARG(0);
431 GET_ARG(1);
432 if (use_gdb_syscalls()) {
433 gdb_do_syscall(nios2_semi_cb, "system,%s",
434 arg0, (int)arg1);
435 return;
436 } else {
437 p = lock_user_string(arg0);
438 if (!p) {
439 result = -1;
440 errno = EFAULT;
441 } else {
442 result = system(p);
443 unlock_user(p, arg0, 0);
444 }
445 }
446 break;
447 default:
448 qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
449 "semihosting syscall %d\n", nr);
450 result = 0;
451 }
452failed:
453 nios2_semi_return_u32(env, result, errno);
454}
455