[qemu.git] / m68k-semi.c

/*
 *  m68k/ColdFire Semihosting syscall interface
 *
 *  Copyright (c) 2005-2007 CodeSourcery.
 *
 *  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, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#include <time.h>

#include "cpu.h"
#if defined(CONFIG_USER_ONLY)
#include "qemu.h"
#define SEMIHOSTING_HEAP_SIZE (128 * 1024 * 1024)
#else
#include "vl.h"
#include "softmmu-semi.h"
#endif

#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 m68k_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 */
} __attribute__((packed));

struct gdb_timeval {
  gdb_time_t tv_sec;  /* second */
  uint64_t tv_usec;   /* microsecond */
} __attribute__((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 void translate_stat(CPUState *env, target_ulong addr, struct stat *s)
{
    struct m68k_gdb_stat *p;

    p = lock_user(addr, sizeof(struct m68k_gdb_stat), 0);
    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 m68k_gdb_stat));
}

static int m68k_semi_is_fseek;

static void m68k_semi_cb(CPUState *env, target_ulong ret, target_ulong err)
{
    target_ulong args;

    args = env->dregs[1];
    if (m68k_semi_is_fseek) {
        /* FIXME: We've already lost the high bits of the fseek
           return value.  */
        tput32(args, 0);
        args += 4;
        m68k_semi_is_fseek = 0;
    }
    tput32(args, ret);
    tput32(args + 4, errno);
}

#define ARG(x) tget32(args + (x) * 4)
#define PARG(x) ((unsigned long)ARG(x))
void do_m68k_semihosting(CPUM68KState *env, int nr)
{
    uint32_t args;
    void *p;
    void *q;
    uint32_t len;
    uint32_t result;

    args = env->dregs[1];
    switch (nr) {
    case HOSTED_EXIT:
        exit(env->dregs[0]);
    case HOSTED_OPEN:
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "open,%s,%x,%x", ARG(0), (int)ARG(1),
                           ARG(2), ARG(3));
            return;
        } else {
            p = lock_user_string(ARG(0));
            result = open(p, translate_openflags(ARG(2)), ARG(3));
            unlock_user(p, ARG(0), 0);
        }
        break;
    case HOSTED_CLOSE:
        {
            /* Ignore attempts to close stdin/out/err.  */
            int fd = ARG(0);
            if (fd > 2) {
                if (use_gdb_syscalls()) {
                    gdb_do_syscall(m68k_semi_cb, "close,%x", ARG(0));
                    return;
                } else {
                    result = close(fd);
                }
            } else {
                result = 0;
            }
            break;
        }
    case HOSTED_READ:
        len = ARG(2);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "read,%x,%x,%x",
                           ARG(0), ARG(1), len);
            return;
        } else {
            p = lock_user(ARG(1), len, 0);
            result = read(ARG(0), p, len);
            unlock_user(p, ARG(1), len);
        }
        break;
    case HOSTED_WRITE:
        len = ARG(2);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "write,%x,%x,%x",
                           ARG(0), ARG(1), len);
            return;
        } else {
            p = lock_user(ARG(1), len, 1);
            result = write(ARG(0), p, len);
            unlock_user(p, ARG(0), 0);
        }
        break;
    case HOSTED_LSEEK:
        {
            uint64_t off;
            off = (uint32_t)ARG(2) | ((uint64_t)ARG(1) << 32);
            if (use_gdb_syscalls()) {
                m68k_semi_is_fseek = 1;
                gdb_do_syscall(m68k_semi_cb, "fseek,%x,%lx,%x",
                               ARG(0), off, ARG(3));
            } else {
                off = lseek(ARG(0), off, ARG(3));
                tput32(args, off >> 32);
                tput32(args + 4, off);
                tput32(args + 8, errno);
            }
            return;
        }
    case HOSTED_RENAME:
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "rename,%s,%s",
                           ARG(0), (int)ARG(1), ARG(2), (int)ARG(3));
            return;
        } else {
            p = lock_user_string(ARG(0));
            q = lock_user_string(ARG(2));
            result = rename(p, q);
            unlock_user(p, ARG(0), 0);
            unlock_user(q, ARG(2), 0);
        }
        break;
    case HOSTED_UNLINK:
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "unlink,%s",
                           ARG(0), (int)ARG(1));
            return;
        } else {
            p = lock_user_string(ARG(0));
            result = unlink(p);
            unlock_user(p, ARG(0), 0);
        }
        break;
    case HOSTED_STAT:
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "stat,%s,%x",
                           ARG(0), (int)ARG(1), ARG(2));
            return;
        } else {
            struct stat s;
            p = lock_user_string(ARG(0));
            result = stat(p, &s);
            unlock_user(p, ARG(0), 0);
            if (result == 0) {
                translate_stat(env, ARG(2), &s);
            }
        }
        break;
    case HOSTED_FSTAT:
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "fstat,%x,%x",
                           ARG(0), ARG(1));
            return;
        } else {
            struct stat s;
            result = fstat(ARG(0), &s);
            if (result == 0) {
                translate_stat(env, ARG(1), &s);
            }
        }
        break;
    case HOSTED_GETTIMEOFDAY:
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "gettimeofday,%x,%x",
                           ARG(0), ARG(1));
            return;
        } else {
            qemu_timeval tv;
            struct gdb_timeval *p;
            result = qemu_gettimeofday(&tv);
            if (result != 0) {
                p = lock_user(ARG(0), sizeof(struct gdb_timeval), 0);
                p->tv_sec = cpu_to_be32(tv.tv_sec);
                p->tv_usec = cpu_to_be64(tv.tv_usec);
                unlock_user(p, ARG(0), sizeof(struct gdb_timeval));
            }
        }
        break;
    case HOSTED_ISATTY:
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "isatty,%x", ARG(0));
            return;
        } else {
            result = isatty(ARG(0));
        }
        break;
    case HOSTED_SYSTEM:
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "system,%s",
                           ARG(0), (int)ARG(1));
            return;
        } else {
            p = lock_user_string(ARG(0));
            result = system(p);
            unlock_user(p, ARG(0), 0);
        }
        break;
    case HOSTED_INIT_SIM:
#if defined(CONFIG_USER_ONLY)
        {
        TaskState *ts = env->opaque;
        /* Allocate the heap using sbrk.  */
        if (!ts->heap_limit) {
            long ret;
            uint32_t size;
            uint32_t base;

            base = do_brk(0);
            size = SEMIHOSTING_HEAP_SIZE;
            /* Try a big heap, and reduce the size if that fails.  */
            for (;;) {
                ret = do_brk(base + size);
                if (ret != -1)
                    break;
                size >>= 1;
            }
            ts->heap_limit = base + size;
        }
        /* This call may happen before we have writable memory, so return
           values directly in registers.  */
        env->dregs[1] = ts->heap_limit;
        env->aregs[7] = ts->stack_base;
        }
#else
        /* FIXME: This is wrong for boards where RAM does not start at
           address zero.  */
        env->dregs[1] = ram_size;
        env->aregs[7] = ram_size;
#endif
        return;
    default:
        cpu_abort(env, "Unsupported semihosting syscall %d\n", nr);
        result = 0;
    }
    tput32(args, result);
    tput32(args + 4, errno);
}
Commit	Line	Data
a87295e8 PB	1	/*
a87295e8 PB	2	* m68k/ColdFire Semihosting syscall interface
5fafdf24	3	*
a87295e8 PB	4	* Copyright (c) 2005-2007 CodeSourcery.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	19	*/
	20
	21	#include <sys/types.h>
	22	#include <sys/stat.h>
	23	#include <errno.h>
	24	#include <fcntl.h>
	25	#include <unistd.h>
	26	#include <stdlib.h>
	27	#include <stdio.h>
	28	#include <sys/time.h>
	29	#include <time.h>
	30
	31	#include "cpu.h"
	32	#if defined(CONFIG_USER_ONLY)
	33	#include "qemu.h"
	34	#define SEMIHOSTING_HEAP_SIZE (128 * 1024 * 1024)
	35	#else
	36	#include "vl.h"
	37	#include "softmmu-semi.h"
	38	#endif
	39
	40	#define HOSTED_EXIT 0
	41	#define HOSTED_INIT_SIM 1
	42	#define HOSTED_OPEN 2
	43	#define HOSTED_CLOSE 3
	44	#define HOSTED_READ 4
	45	#define HOSTED_WRITE 5
	46	#define HOSTED_LSEEK 6
	47	#define HOSTED_RENAME 7
	48	#define HOSTED_UNLINK 8
	49	#define HOSTED_STAT 9
	50	#define HOSTED_FSTAT 10
	51	#define HOSTED_GETTIMEOFDAY 11
	52	#define HOSTED_ISATTY 12
	53	#define HOSTED_SYSTEM 13
	54
	55	typedef uint32_t gdb_mode_t;
	56	typedef uint32_t gdb_time_t;
	57
	58	struct m68k_gdb_stat {
	59	uint32_t gdb_st_dev; /* device */
	60	uint32_t gdb_st_ino; /* inode */
	61	gdb_mode_t gdb_st_mode; /* protection */
	62	uint32_t gdb_st_nlink; /* number of hard links */
	63	uint32_t gdb_st_uid; /* user ID of owner */
	64	uint32_t gdb_st_gid; /* group ID of owner */
	65	uint32_t gdb_st_rdev; /* device type (if inode device) */
	66	uint64_t gdb_st_size; /* total size, in bytes */
	67	uint64_t gdb_st_blksize; /* blocksize for filesystem I/O */
68	uint64_t gdb_st_blocks; /* number of blocks allocated */
69	gdb_time_t gdb_st_atime; /* time of last access */
70	gdb_time_t gdb_st_mtime; /* time of last modification */
71	gdb_time_t gdb_st_ctime; /* time of last change */
72	} __attribute__((packed));
73
74	struct gdb_timeval {
75	gdb_time_t tv_sec; /* second */
76	uint64_t tv_usec; /* microsecond */
77	} __attribute__((packed));
78
79	#define GDB_O_RDONLY 0x0
80	#define GDB_O_WRONLY 0x1
81	#define GDB_O_RDWR 0x2
82	#define GDB_O_APPEND 0x8
83	#define GDB_O_CREAT 0x200
84	#define GDB_O_TRUNC 0x400
85	#define GDB_O_EXCL 0x800
86
87	static int translate_openflags(int flags)
88	{
89	int hf;
90
91	if (flags & GDB_O_WRONLY)
92	hf = O_WRONLY;
93	else if (flags & GDB_O_RDWR)
94	hf = O_RDWR;
95	else
96	hf = O_RDONLY;
97
98	if (flags & GDB_O_APPEND) hf \|= O_APPEND;
99	if (flags & GDB_O_CREAT) hf \|= O_CREAT;
100	if (flags & GDB_O_TRUNC) hf \|= O_TRUNC;
101	if (flags & GDB_O_EXCL) hf \|= O_EXCL;
102
103	return hf;
104	}
105
106	static void translate_stat(CPUState env, target_ulong addr, struct stat s)
107	{
108	struct m68k_gdb_stat *p;
109
110	p = lock_user(addr, sizeof(struct m68k_gdb_stat), 0);
111	p->gdb_st_dev = cpu_to_be32(s->st_dev);
112	p->gdb_st_ino = cpu_to_be32(s->st_ino);
113	p->gdb_st_mode = cpu_to_be32(s->st_mode);
114	p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
115	p->gdb_st_uid = cpu_to_be32(s->st_uid);
116	p->gdb_st_gid = cpu_to_be32(s->st_gid);
117	p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
118	p->gdb_st_size = cpu_to_be64(s->st_size);
29b3a662 PB	119	#ifdef _WIN32
	120	/* Windows stat is missing some fields. */
	121	p->gdb_st_blksize = 0;
	122	p->gdb_st_blocks = 0;
	123	#else
a87295e8 PB	124	p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
a87295e8 PB	125	p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
29b3a662	126	#endif
a87295e8 PB	127	p->gdb_st_atime = cpu_to_be32(s->st_atime);
	128	p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
	129	p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
	130	unlock_user(p, addr, sizeof(struct m68k_gdb_stat));
	131	}
	132
	133	static int m68k_semi_is_fseek;
	134
	135	static void m68k_semi_cb(CPUState *env, target_ulong ret, target_ulong err)
	136	{
	137	target_ulong args;
	138
	139	args = env->dregs[1];
	140	if (m68k_semi_is_fseek) {
	141	/* FIXME: We've already lost the high bits of the fseek
	142	return value. */
	143	tput32(args, 0);
	144	args += 4;
	145	m68k_semi_is_fseek = 0;
	146	}
	147	tput32(args, ret);
	148	tput32(args + 4, errno);
	149	}
	150
	151	#define ARG(x) tget32(args + (x) * 4)
	152	#define PARG(x) ((unsigned long)ARG(x))
	153	void do_m68k_semihosting(CPUM68KState *env, int nr)
	154	{
	155	uint32_t args;
	156	void *p;
	157	void *q;
	158	uint32_t len;
	159	uint32_t result;
	160
	161	args = env->dregs[1];
	162	switch (nr) {
	163	case HOSTED_EXIT:
	164	exit(env->dregs[0]);
	165	case HOSTED_OPEN:
	166	if (use_gdb_syscalls()) {
	167	gdb_do_syscall(m68k_semi_cb, "open,%s,%x,%x", ARG(0), (int)ARG(1),
	168	ARG(2), ARG(3));
	169	return;
	170	} else {
	171	p = lock_user_string(ARG(0));
	172	result = open(p, translate_openflags(ARG(2)), ARG(3));
	173	unlock_user(p, ARG(0), 0);
	174	}
	175	break;
	176	case HOSTED_CLOSE:
	177	{
	178	/* Ignore attempts to close stdin/out/err. */
	179	int fd = ARG(0);
	180	if (fd > 2) {
	181	if (use_gdb_syscalls()) {
	182	gdb_do_syscall(m68k_semi_cb, "close,%x", ARG(0));
	183	return;
	184	} else {
	185	result = close(fd);
	186	}
	187	} else {
	188	result = 0;
	189	}
	190	break;
191	}
192	case HOSTED_READ:
193	len = ARG(2);
194	if (use_gdb_syscalls()) {
195	gdb_do_syscall(m68k_semi_cb, "read,%x,%x,%x",
196	ARG(0), ARG(1), len);
197	return;
198	} else {
199	p = lock_user(ARG(1), len, 0);
200	result = read(ARG(0), p, len);
201	unlock_user(p, ARG(1), len);
202	}
203	break;
204	case HOSTED_WRITE:
205	len = ARG(2);
206	if (use_gdb_syscalls()) {
207	gdb_do_syscall(m68k_semi_cb, "write,%x,%x,%x",
208	ARG(0), ARG(1), len);
209	return;
210	} else {
211	p = lock_user(ARG(1), len, 1);
212	result = write(ARG(0), p, len);
213	unlock_user(p, ARG(0), 0);
214	}
215	break;
216	case HOSTED_LSEEK:
217	{
218	uint64_t off;
219	off = (uint32_t)ARG(2) \| ((uint64_t)ARG(1) << 32);
220	if (use_gdb_syscalls()) {
221	m68k_semi_is_fseek = 1;
222	gdb_do_syscall(m68k_semi_cb, "fseek,%x,%lx,%x",
223	ARG(0), off, ARG(3));
224	} else {
225	off = lseek(ARG(0), off, ARG(3));
226	tput32(args, off >> 32);
227	tput32(args + 4, off);
228	tput32(args + 8, errno);
229	}
230	return;
231	}
232	case HOSTED_RENAME:
233	if (use_gdb_syscalls()) {
5fafdf24	234	gdb_do_syscall(m68k_semi_cb, "rename,%s,%s",
a87295e8 PB	235	ARG(0), (int)ARG(1), ARG(2), (int)ARG(3));
	236	return;
	237	} else {
	238	p = lock_user_string(ARG(0));
	239	q = lock_user_string(ARG(2));
	240	result = rename(p, q);
	241	unlock_user(p, ARG(0), 0);
	242	unlock_user(q, ARG(2), 0);
	243	}
	244	break;
	245	case HOSTED_UNLINK:
	246	if (use_gdb_syscalls()) {
	247	gdb_do_syscall(m68k_semi_cb, "unlink,%s",
	248	ARG(0), (int)ARG(1));
	249	return;
	250	} else {
	251	p = lock_user_string(ARG(0));
	252	result = unlink(p);
	253	unlock_user(p, ARG(0), 0);
	254	}
	255	break;
	256	case HOSTED_STAT:
	257	if (use_gdb_syscalls()) {
	258	gdb_do_syscall(m68k_semi_cb, "stat,%s,%x",
	259	ARG(0), (int)ARG(1), ARG(2));
	260	return;
	261	} else {
	262	struct stat s;
	263	p = lock_user_string(ARG(0));
	264	result = stat(p, &s);
	265	unlock_user(p, ARG(0), 0);
	266	if (result == 0) {
	267	translate_stat(env, ARG(2), &s);
	268	}
	269	}
	270	break;
	271	case HOSTED_FSTAT:
	272	if (use_gdb_syscalls()) {
	273	gdb_do_syscall(m68k_semi_cb, "fstat,%x,%x",
	274	ARG(0), ARG(1));
	275	return;
	276	} else {
	277	struct stat s;
	278	result = fstat(ARG(0), &s);
	279	if (result == 0) {
	280	translate_stat(env, ARG(1), &s);
	281	}
	282	}
	283	break;
	284	case HOSTED_GETTIMEOFDAY:
	285	if (use_gdb_syscalls()) {
	286	gdb_do_syscall(m68k_semi_cb, "gettimeofday,%x,%x",
	287	ARG(0), ARG(1));
	288	return;
	289	} else {
29b3a662	290	qemu_timeval tv;
a87295e8	291	struct gdb_timeval *p;
29b3a662	292	result = qemu_gettimeofday(&tv);
a87295e8 PB	293	if (result != 0) {
	294	p = lock_user(ARG(0), sizeof(struct gdb_timeval), 0);
	295	p->tv_sec = cpu_to_be32(tv.tv_sec);
	296	p->tv_usec = cpu_to_be64(tv.tv_usec);
	297	unlock_user(p, ARG(0), sizeof(struct gdb_timeval));
	298	}
	299	}
	300	break;
	301	case HOSTED_ISATTY:
	302	if (use_gdb_syscalls()) {
	303	gdb_do_syscall(m68k_semi_cb, "isatty,%x", ARG(0));
	304	return;
	305	} else {
	306	result = isatty(ARG(0));
	307	}
	308	break;
	309	case HOSTED_SYSTEM:
	310	if (use_gdb_syscalls()) {
	311	gdb_do_syscall(m68k_semi_cb, "system,%s",
	312	ARG(0), (int)ARG(1));
	313	return;
	314	} else {
	315	p = lock_user_string(ARG(0));
	316	result = system(p);
	317	unlock_user(p, ARG(0), 0);
	318	}
	319	break;
	320	case HOSTED_INIT_SIM:
	321	#if defined(CONFIG_USER_ONLY)
	322	{
	323	TaskState *ts = env->opaque;
	324	/* Allocate the heap using sbrk. */
	325	if (!ts->heap_limit) {
	326	long ret;
	327	uint32_t size;
	328	uint32_t base;
	329
	330	base = do_brk(0);
	331	size = SEMIHOSTING_HEAP_SIZE;
	332	/* Try a big heap, and reduce the size if that fails. */
	333	for (;;) {
	334	ret = do_brk(base + size);
	335	if (ret != -1)
	336	break;
	337	size >>= 1;
	338	}
	339	ts->heap_limit = base + size;
	340	}
	341	/* This call may happen before we have writable memory, so return
	342	values directly in registers. */
	343	env->dregs[1] = ts->heap_limit;
	344	env->aregs[7] = ts->stack_base;
	345	}
	346	#else
	347	/* FIXME: This is wrong for boards where RAM does not start at
	348	address zero. */
	349	env->dregs[1] = ram_size;
	350	env->aregs[7] = ram_size;
	351	#endif
	352	return;
	353	default:
	354	cpu_abort(env, "Unsupported semihosting syscall %d\n", nr);
	355	result = 0;
	356	}
357	tput32(args, result);
358	tput32(args + 4, errno);
359	}