[qemu.git] / target / nios2 / nios2-semi.c

/*
 *  Nios II Semihosting syscall interface.
 *  This code is derived from m68k-semi.c.
 *  The semihosting protocol implemented here is described in the
 *  libgloss sources:
 *  https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=blob;f=libgloss/nios2/nios2-semi.txt;hb=HEAD
 *
 *  Copyright (c) 2017-2019 Mentor Graphics
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "qemu/osdep.h"

#include "cpu.h"
#if defined(CONFIG_USER_ONLY)
#include "qemu.h"
#else
#include "qemu-common.h"
#include "exec/gdbstub.h"
#include "exec/softmmu-semi.h"
#endif
#include "qemu/log.h"
#include "sysemu/sysemu.h"

#define HOSTED_EXIT  0
#define HOSTED_INIT_SIM 1
#define HOSTED_OPEN 2
#define HOSTED_CLOSE 3
#define HOSTED_READ 4
#define HOSTED_WRITE 5
#define HOSTED_LSEEK 6
#define HOSTED_RENAME 7
#define HOSTED_UNLINK 8
#define HOSTED_STAT 9
#define HOSTED_FSTAT 10
#define HOSTED_GETTIMEOFDAY 11
#define HOSTED_ISATTY 12
#define HOSTED_SYSTEM 13

typedef uint32_t gdb_mode_t;
typedef uint32_t gdb_time_t;

struct nios2_gdb_stat {
  uint32_t    gdb_st_dev;     /* device */
  uint32_t    gdb_st_ino;     /* inode */
  gdb_mode_t  gdb_st_mode;    /* protection */
  uint32_t    gdb_st_nlink;   /* number of hard links */
  uint32_t    gdb_st_uid;     /* user ID of owner */
  uint32_t    gdb_st_gid;     /* group ID of owner */
  uint32_t    gdb_st_rdev;    /* device type (if inode device) */
  uint64_t    gdb_st_size;    /* total size, in bytes */
  uint64_t    gdb_st_blksize; /* blocksize for filesystem I/O */
  uint64_t    gdb_st_blocks;  /* number of blocks allocated */
  gdb_time_t  gdb_st_atime;   /* time of last access */
  gdb_time_t  gdb_st_mtime;   /* time of last modification */
  gdb_time_t  gdb_st_ctime;   /* time of last change */
} QEMU_PACKED;

struct gdb_timeval {
  gdb_time_t tv_sec;  /* second */
  uint64_t tv_usec;   /* microsecond */
} QEMU_PACKED;

#define GDB_O_RDONLY   0x0
#define GDB_O_WRONLY   0x1
#define GDB_O_RDWR     0x2
#define GDB_O_APPEND   0x8
#define GDB_O_CREAT  0x200
#define GDB_O_TRUNC  0x400
#define GDB_O_EXCL   0x800

static int translate_openflags(int flags)
{
    int hf;

    if (flags & GDB_O_WRONLY) {
        hf = O_WRONLY;
    } else if (flags & GDB_O_RDWR) {
        hf = O_RDWR;
    } else {
        hf = O_RDONLY;
    }

    if (flags & GDB_O_APPEND) {
        hf |= O_APPEND;
    }
    if (flags & GDB_O_CREAT) {
        hf |= O_CREAT;
    }
    if (flags & GDB_O_TRUNC) {
        hf |= O_TRUNC;
    }
    if (flags & GDB_O_EXCL) {
        hf |= O_EXCL;
    }

    return hf;
}

static bool translate_stat(CPUNios2State *env, target_ulong addr,
                           struct stat *s)
{
    struct nios2_gdb_stat *p;

    p = lock_user(VERIFY_WRITE, addr, sizeof(struct nios2_gdb_stat), 0);

    if (!p) {
        return false;
    }
    p->gdb_st_dev = cpu_to_be32(s->st_dev);
    p->gdb_st_ino = cpu_to_be32(s->st_ino);
    p->gdb_st_mode = cpu_to_be32(s->st_mode);
    p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
    p->gdb_st_uid = cpu_to_be32(s->st_uid);
    p->gdb_st_gid = cpu_to_be32(s->st_gid);
    p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
    p->gdb_st_size = cpu_to_be64(s->st_size);
#ifdef _WIN32
    /* Windows stat is missing some fields.  */
    p->gdb_st_blksize = 0;
    p->gdb_st_blocks = 0;
#else
    p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
    p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
#endif
    p->gdb_st_atime = cpu_to_be32(s->st_atime);
    p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
    p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
    unlock_user(p, addr, sizeof(struct nios2_gdb_stat));
    return true;
}

static void nios2_semi_return_u32(CPUNios2State *env, uint32_t ret,
                                  uint32_t err)
{
    target_ulong args = env->regs[R_ARG1];
    if (put_user_u32(ret, args) ||
        put_user_u32(err, args + 4)) {
        /*
         * The nios2 semihosting ABI does not provide any way to report this
         * error to the guest, so the best we can do is log it in qemu.
         * It is always a guest error not to pass us a valid argument block.
         */
        qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
                      "discarded because argument block not writable\n");
    }
}

static void nios2_semi_return_u64(CPUNios2State *env, uint64_t ret,
                                  uint32_t err)
{
    target_ulong args = env->regs[R_ARG1];
    if (put_user_u32(ret >> 32, args) ||
        put_user_u32(ret, args + 4) ||
        put_user_u32(err, args + 8)) {
        /* No way to report this via nios2 semihosting ABI; just log it */
        qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
                      "discarded because argument block not writable\n");
    }
}

static int nios2_semi_is_lseek;

static void nios2_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
{
    Nios2CPU *cpu = NIOS2_CPU(cs);
    CPUNios2State *env = &cpu->env;

    if (nios2_semi_is_lseek) {
        /*
         * FIXME: We've already lost the high bits of the lseek
         * return value.
         */
        nios2_semi_return_u64(env, ret, err);
        nios2_semi_is_lseek = 0;
    } else {
        nios2_semi_return_u32(env, ret, err);
    }
}

/*
 * Read the input value from the argument block; fail the semihosting
 * call if the memory read fails.
 */
#define GET_ARG(n) do {                                 \
    if (get_user_ual(arg ## n, args + (n) * 4)) {       \
        result = -1;                                    \
        errno = EFAULT;                                 \
        goto failed;                                    \
    }                                                   \
} while (0)

void do_nios2_semihosting(CPUNios2State *env)
{
    int nr;
    uint32_t args;
    target_ulong arg0, arg1, arg2, arg3;
    void *p;
    void *q;
    uint32_t len;
    uint32_t result;

    nr = env->regs[R_ARG0];
    args = env->regs[R_ARG1];
    switch (nr) {
    case HOSTED_EXIT:
        gdb_exit(env, env->regs[R_ARG0]);
        exit(env->regs[R_ARG0]);
    case HOSTED_OPEN:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        GET_ARG(3);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "open,%s,%x,%x", arg0, (int)arg1,
                           arg2, arg3);
            return;
        } else {
            p = lock_user_string(arg0);
            if (!p) {
                result = -1;
                errno = EFAULT;
            } else {
                result = open(p, translate_openflags(arg2), arg3);
                unlock_user(p, arg0, 0);
            }
        }
        break;
    case HOSTED_CLOSE:
        {
            /* Ignore attempts to close stdin/out/err.  */
            GET_ARG(0);
            int fd = arg0;
            if (fd > 2) {
                if (use_gdb_syscalls()) {
                    gdb_do_syscall(nios2_semi_cb, "close,%x", arg0);
                    return;
                } else {
                    result = close(fd);
                }
            } else {
                result = 0;
            }
            break;
        }
    case HOSTED_READ:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        len = arg2;
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "read,%x,%x,%x",
                           arg0, arg1, len);
            return;
        } else {
            p = lock_user(VERIFY_WRITE, arg1, len, 0);
            if (!p) {
                result = -1;
                errno = EFAULT;
            } else {
                result = read(arg0, p, len);
                unlock_user(p, arg1, len);
            }
        }
        break;
    case HOSTED_WRITE:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        len = arg2;
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "write,%x,%x,%x",
                           arg0, arg1, len);
            return;
        } else {
            p = lock_user(VERIFY_READ, arg1, len, 1);
            if (!p) {
                result = -1;
                errno = EFAULT;
            } else {
                result = write(arg0, p, len);
                unlock_user(p, arg0, 0);
            }
        }
        break;
    case HOSTED_LSEEK:
        {
            uint64_t off;
            GET_ARG(0);
            GET_ARG(1);
            GET_ARG(2);
            GET_ARG(3);
            off = (uint32_t)arg2 | ((uint64_t)arg1 << 32);
            if (use_gdb_syscalls()) {
                nios2_semi_is_lseek = 1;
                gdb_do_syscall(nios2_semi_cb, "lseek,%x,%lx,%x",
                               arg0, off, arg3);
            } else {
                off = lseek(arg0, off, arg3);
                nios2_semi_return_u64(env, off, errno);
            }
            return;
        }
    case HOSTED_RENAME:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        GET_ARG(3);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "rename,%s,%s",
                           arg0, (int)arg1, arg2, (int)arg3);
            return;
        } else {
            p = lock_user_string(arg0);
            q = lock_user_string(arg2);
            if (!p || !q) {
                result = -1;
                errno = EFAULT;
            } else {
                result = rename(p, q);
            }
            unlock_user(p, arg0, 0);
            unlock_user(q, arg2, 0);
        }
        break;
    case HOSTED_UNLINK:
        GET_ARG(0);
        GET_ARG(1);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "unlink,%s",
                           arg0, (int)arg1);
            return;
        } else {
            p = lock_user_string(arg0);
            if (!p) {
                result = -1;
                errno = EFAULT;
            } else {
                result = unlink(p);
                unlock_user(p, arg0, 0);
            }
        }
        break;
    case HOSTED_STAT:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "stat,%s,%x",
                           arg0, (int)arg1, arg2);
            return;
        } else {
            struct stat s;
            p = lock_user_string(arg0);
            if (!p) {
                result = -1;
                errno = EFAULT;
            } else {
                result = stat(p, &s);
                unlock_user(p, arg0, 0);
            }
            if (result == 0 && !translate_stat(env, arg2, &s)) {
                result = -1;
                errno = EFAULT;
            }
        }
        break;
    case HOSTED_FSTAT:
        GET_ARG(0);
        GET_ARG(1);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "fstat,%x,%x",
                           arg0, arg1);
            return;
        } else {
            struct stat s;
            result = fstat(arg0, &s);
            if (result == 0 && !translate_stat(env, arg1, &s)) {
                result = -1;
                errno = EFAULT;
            }
        }
        break;
    case HOSTED_GETTIMEOFDAY:
        /* Only the tv parameter is used.  tz is assumed NULL.  */
        GET_ARG(0);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "gettimeofday,%x,%x",
                           arg0, 0);
            return;
        } else {
            qemu_timeval tv;
            struct gdb_timeval *p;
            result = qemu_gettimeofday(&tv);
            if (result != 0) {
                p = lock_user(VERIFY_WRITE, arg0, sizeof(struct gdb_timeval),
                              0);
                if (!p) {
                    result = -1;
                    errno = EFAULT;
                } else {
                    p->tv_sec = cpu_to_be32(tv.tv_sec);
                    p->tv_usec = cpu_to_be64(tv.tv_usec);
                    unlock_user(p, arg0, sizeof(struct gdb_timeval));
                }
            }
        }
        break;
    case HOSTED_ISATTY:
        GET_ARG(0);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "isatty,%x", arg0);
            return;
        } else {
            result = isatty(arg0);
        }
        break;
    case HOSTED_SYSTEM:
        GET_ARG(0);
        GET_ARG(1);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(nios2_semi_cb, "system,%s",
                           arg0, (int)arg1);
            return;
        } else {
            p = lock_user_string(arg0);
            if (!p) {
                result = -1;
                errno = EFAULT;
            } else {
                result = system(p);
                unlock_user(p, arg0, 0);
            }
        }
        break;
    default:
        qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
                      "semihosting syscall %d\n", nr);
        result = 0;
    }
failed:
    nios2_semi_return_u32(env, result, errno);
}
Commit	Line	Data
413a99a9 SL	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	#include "sysemu/sysemu.h"
	36
	37	#define HOSTED_EXIT 0
	38	#define HOSTED_INIT_SIM 1
	39	#define HOSTED_OPEN 2
	40	#define HOSTED_CLOSE 3
	41	#define HOSTED_READ 4
	42	#define HOSTED_WRITE 5
	43	#define HOSTED_LSEEK 6
	44	#define HOSTED_RENAME 7
	45	#define HOSTED_UNLINK 8
	46	#define HOSTED_STAT 9
	47	#define HOSTED_FSTAT 10
	48	#define HOSTED_GETTIMEOFDAY 11
	49	#define HOSTED_ISATTY 12
	50	#define HOSTED_SYSTEM 13
	51
	52	typedef uint32_t gdb_mode_t;
	53	typedef uint32_t gdb_time_t;
	54
	55	struct nios2_gdb_stat {
	56	uint32_t gdb_st_dev; /* device */
	57	uint32_t gdb_st_ino; /* inode */
	58	gdb_mode_t gdb_st_mode; /* protection */
	59	uint32_t gdb_st_nlink; /* number of hard links */
	60	uint32_t gdb_st_uid; /* user ID of owner */
	61	uint32_t gdb_st_gid; /* group ID of owner */
	62	uint32_t gdb_st_rdev; /* device type (if inode device) */
	63	uint64_t gdb_st_size; /* total size, in bytes */
	64	uint64_t gdb_st_blksize; /* blocksize for filesystem I/O */
65	uint64_t gdb_st_blocks; /* number of blocks allocated */
66	gdb_time_t gdb_st_atime; /* time of last access */
67	gdb_time_t gdb_st_mtime; /* time of last modification */
68	gdb_time_t gdb_st_ctime; /* time of last change */
69	} QEMU_PACKED;
70
71	struct gdb_timeval {
72	gdb_time_t tv_sec; /* second */
73	uint64_t tv_usec; /* microsecond */
74	} QEMU_PACKED;
75
76	#define GDB_O_RDONLY 0x0
77	#define GDB_O_WRONLY 0x1
78	#define GDB_O_RDWR 0x2
79	#define GDB_O_APPEND 0x8
80	#define GDB_O_CREAT 0x200
81	#define GDB_O_TRUNC 0x400
82	#define GDB_O_EXCL 0x800
83
84	static int translate_openflags(int flags)
85	{
86	int hf;
87
88	if (flags & GDB_O_WRONLY) {
89	hf = O_WRONLY;
90	} else if (flags & GDB_O_RDWR) {
91	hf = O_RDWR;
92	} else {
93	hf = O_RDONLY;
94	}
95
96	if (flags & GDB_O_APPEND) {
97	hf \|= O_APPEND;
98	}
99	if (flags & GDB_O_CREAT) {
100	hf \|= O_CREAT;
101	}
102	if (flags & GDB_O_TRUNC) {
103	hf \|= O_TRUNC;
104	}
105	if (flags & GDB_O_EXCL) {
106	hf \|= O_EXCL;
107	}
108
109	return hf;
110	}
111
112	static bool translate_stat(CPUNios2State *env, target_ulong addr,
113	struct stat *s)
114	{
115	struct nios2_gdb_stat *p;
116
117	p = lock_user(VERIFY_WRITE, addr, sizeof(struct nios2_gdb_stat), 0);
118
119	if (!p) {
120	return false;
121	}
122	p->gdb_st_dev = cpu_to_be32(s->st_dev);
123	p->gdb_st_ino = cpu_to_be32(s->st_ino);
124	p->gdb_st_mode = cpu_to_be32(s->st_mode);
125	p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
126	p->gdb_st_uid = cpu_to_be32(s->st_uid);
127	p->gdb_st_gid = cpu_to_be32(s->st_gid);
128	p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
129	p->gdb_st_size = cpu_to_be64(s->st_size);
130	#ifdef _WIN32
131	/* Windows stat is missing some fields. */
132	p->gdb_st_blksize = 0;
133	p->gdb_st_blocks = 0;
134	#else
135	p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
136	p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
137	#endif
138	p->gdb_st_atime = cpu_to_be32(s->st_atime);
139	p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
140	p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
141	unlock_user(p, addr, sizeof(struct nios2_gdb_stat));
142	return true;
143	}
144
145	static void nios2_semi_return_u32(CPUNios2State *env, uint32_t ret,
146	uint32_t err)
147	{
148	target_ulong args = env->regs[R_ARG1];
149	if (put_user_u32(ret, args) \|\|
150	put_user_u32(err, args + 4)) {
151	/*
152	* The nios2 semihosting ABI does not provide any way to report this
153	* error to the guest, so the best we can do is log it in qemu.
154	* It is always a guest error not to pass us a valid argument block.
155	*/
156	qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
157	"discarded because argument block not writable\n");
158	}
159	}
160
161	static void nios2_semi_return_u64(CPUNios2State *env, uint64_t ret,
162	uint32_t err)
163	{
164	target_ulong args = env->regs[R_ARG1];
165	if (put_user_u32(ret >> 32, args) \|\|
166	put_user_u32(ret, args + 4) \|\|
167	put_user_u32(err, args + 8)) {
168	/* No way to report this via nios2 semihosting ABI; just log it */
169	qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
170	"discarded because argument block not writable\n");
171	}
172	}
173
174	static int nios2_semi_is_lseek;
175
176	static void nios2_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
177	{
178	Nios2CPU *cpu = NIOS2_CPU(cs);
179	CPUNios2State *env = &cpu->env;
180
181	if (nios2_semi_is_lseek) {
182	/*
183	* FIXME: We've already lost the high bits of the lseek
184	* return value.
185	*/
186	nios2_semi_return_u64(env, ret, err);
187	nios2_semi_is_lseek = 0;
188	} else {
189	nios2_semi_return_u32(env, ret, err);
190	}
191	}
192
193	/*
194	* Read the input value from the argument block; fail the semihosting
195	* call if the memory read fails.
196	*/
197	#define GET_ARG(n) do { \
198	if (get_user_ual(arg ## n, args + (n) * 4)) { \
199	result = -1; \
200	errno = EFAULT; \
201	goto failed; \
202	} \
203	} while (0)
204
205	void do_nios2_semihosting(CPUNios2State *env)
206	{
207	int nr;
208	uint32_t args;
209	target_ulong arg0, arg1, arg2, arg3;
210	void *p;
211	void *q;
212	uint32_t len;
213	uint32_t result;
214
215	nr = env->regs[R_ARG0];
216	args = env->regs[R_ARG1];
217	switch (nr) {
218	case HOSTED_EXIT:
219	gdb_exit(env, env->regs[R_ARG0]);
220	exit(env->regs[R_ARG0]);
221	case HOSTED_OPEN:
222	GET_ARG(0);
223	GET_ARG(1);
224	GET_ARG(2);
225	GET_ARG(3);
226	if (use_gdb_syscalls()) {
227	gdb_do_syscall(nios2_semi_cb, "open,%s,%x,%x", arg0, (int)arg1,
228	arg2, arg3);
229	return;
230	} else {
231	p = lock_user_string(arg0);
232	if (!p) {
233	result = -1;
234	errno = EFAULT;
235	} else {
236	result = open(p, translate_openflags(arg2), arg3);
237	unlock_user(p, arg0, 0);
238	}
239	}
240	break;
241	case HOSTED_CLOSE:
242	{
243	/* Ignore attempts to close stdin/out/err. */
244	GET_ARG(0);
245	int fd = arg0;
246	if (fd > 2) {
247	if (use_gdb_syscalls()) {
248	gdb_do_syscall(nios2_semi_cb, "close,%x", arg0);
249	return;
250	} else {
251	result = close(fd);
252	}
253	} else {
254	result = 0;
255	}
256	break;
257	}
258	case HOSTED_READ:
259	GET_ARG(0);
260	GET_ARG(1);
261	GET_ARG(2);
262	len = arg2;
263	if (use_gdb_syscalls()) {
264	gdb_do_syscall(nios2_semi_cb, "read,%x,%x,%x",
265	arg0, arg1, len);
266	return;
267	} else {
268	p = lock_user(VERIFY_WRITE, arg1, len, 0);
269	if (!p) {
270	result = -1;
271	errno = EFAULT;
272	} else {
273	result = read(arg0, p, len);
274	unlock_user(p, arg1, len);
275	}
276	}
277	break;
278	case HOSTED_WRITE:
279	GET_ARG(0);
280	GET_ARG(1);
281	GET_ARG(2);
282	len = arg2;
283	if (use_gdb_syscalls()) {
284	gdb_do_syscall(nios2_semi_cb, "write,%x,%x,%x",
285	arg0, arg1, len);
286	return;
287	} else {
288	p = lock_user(VERIFY_READ, arg1, len, 1);
289	if (!p) {
290	result = -1;
291	errno = EFAULT;
292	} else {
293	result = write(arg0, p, len);
294	unlock_user(p, arg0, 0);
295	}
296	}
297	break;
298	case HOSTED_LSEEK:
299	{
300	uint64_t off;
301	GET_ARG(0);
302	GET_ARG(1);
303	GET_ARG(2);
304	GET_ARG(3);
305	off = (uint32_t)arg2 \| ((uint64_t)arg1 << 32);
306	if (use_gdb_syscalls()) {
307	nios2_semi_is_lseek = 1;
308	gdb_do_syscall(nios2_semi_cb, "lseek,%x,%lx,%x",
309	arg0, off, arg3);
310	} else {
311	off = lseek(arg0, off, arg3);
312	nios2_semi_return_u64(env, off, errno);
313	}
314	return;
315	}
316	case HOSTED_RENAME:
317	GET_ARG(0);
318	GET_ARG(1);
319	GET_ARG(2);
320	GET_ARG(3);
321	if (use_gdb_syscalls()) {
322	gdb_do_syscall(nios2_semi_cb, "rename,%s,%s",
323	arg0, (int)arg1, arg2, (int)arg3);
324	return;
325	} else {
326	p = lock_user_string(arg0);
327	q = lock_user_string(arg2);
328	if (!p \|\| !q) {
329	result = -1;
330	errno = EFAULT;
331	} else {
332	result = rename(p, q);
333	}
334	unlock_user(p, arg0, 0);
335	unlock_user(q, arg2, 0);
336	}
337	break;
338	case HOSTED_UNLINK:
339	GET_ARG(0);
340	GET_ARG(1);
341	if (use_gdb_syscalls()) {
342	gdb_do_syscall(nios2_semi_cb, "unlink,%s",
343	arg0, (int)arg1);
344	return;
345	} else {
346	p = lock_user_string(arg0);
347	if (!p) {
348	result = -1;
349	errno = EFAULT;
350	} else {
351	result = unlink(p);
352	unlock_user(p, arg0, 0);
353	}
354	}
355	break;
356	case HOSTED_STAT:
357	GET_ARG(0);
358	GET_ARG(1);
359	GET_ARG(2);
360	if (use_gdb_syscalls()) {
361	gdb_do_syscall(nios2_semi_cb, "stat,%s,%x",
362	arg0, (int)arg1, arg2);
363	return;
364	} else {
365	struct stat s;
366	p = lock_user_string(arg0);
367	if (!p) {
368	result = -1;
369	errno = EFAULT;
370	} else {
371	result = stat(p, &s);
372	unlock_user(p, arg0, 0);
373	}
374	if (result == 0 && !translate_stat(env, arg2, &s)) {
375	result = -1;
376	errno = EFAULT;
377	}
378	}
379	break;
380	case HOSTED_FSTAT:
381	GET_ARG(0);
382	GET_ARG(1);
383	if (use_gdb_syscalls()) {
384	gdb_do_syscall(nios2_semi_cb, "fstat,%x,%x",
385	arg0, arg1);
386	return;
387	} else {
388	struct stat s;
389	result = fstat(arg0, &s);
390	if (result == 0 && !translate_stat(env, arg1, &s)) {
391	result = -1;
392	errno = EFAULT;
393	}
394	}
395	break;
396	case HOSTED_GETTIMEOFDAY:
397	/* Only the tv parameter is used. tz is assumed NULL. */
398	GET_ARG(0);
399	if (use_gdb_syscalls()) {
400	gdb_do_syscall(nios2_semi_cb, "gettimeofday,%x,%x",
401	arg0, 0);
402	return;
403	} else {
404	qemu_timeval tv;
405	struct gdb_timeval *p;
406	result = qemu_gettimeofday(&tv);
407	if (result != 0) {
408	p = lock_user(VERIFY_WRITE, arg0, sizeof(struct gdb_timeval),
409	0);
410	if (!p) {
411	result = -1;
412	errno = EFAULT;
413	} else {
414	p->tv_sec = cpu_to_be32(tv.tv_sec);
415	p->tv_usec = cpu_to_be64(tv.tv_usec);
416	unlock_user(p, arg0, sizeof(struct gdb_timeval));
417	}
418	}
419	}
420	break;
421	case HOSTED_ISATTY:
422	GET_ARG(0);
423	if (use_gdb_syscalls()) {
424	gdb_do_syscall(nios2_semi_cb, "isatty,%x", arg0);
425	return;
426	} else {
427	result = isatty(arg0);
428	}
429	break;
430	case HOSTED_SYSTEM:
431	GET_ARG(0);
432	GET_ARG(1);
433	if (use_gdb_syscalls()) {
434	gdb_do_syscall(nios2_semi_cb, "system,%s",
435	arg0, (int)arg1);
436	return;
437	} else {
438	p = lock_user_string(arg0);
439	if (!p) {
440	result = -1;
441	errno = EFAULT;
442	} else {
443	result = system(p);
444	unlock_user(p, arg0, 0);
445	}
446	}
447	break;
448	default:
449	qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
450	"semihosting syscall %d\n", nr);
451	result = 0;
452	}
453	failed:
454	nios2_semi_return_u32(env, result, errno);
455	}