M68k system mode semihosting.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2861 c046a42c-6fe2-441c-8c8c-71466251a162

13 files changed, 415 insertions, 283 deletions

diff --git a/Makefile.target b/Makefile.target
index d066cc03db..45928f3c49 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -468,6 +468,7 @@ VL_OBJS+= shix.o sh7750.o sh7750_regnames.o tc58128.o
 endif
 ifeq ($(TARGET_BASE_ARCH), m68k)
 VL_OBJS+= an5206.o mcf5206.o ptimer.o
+VL_OBJS+= m68k-semi.o
 endif
 ifdef CONFIG_GDBSTUB
 VL_OBJS+=gdbstub.o 
diff --git a/arm-semi.c b/arm-semi.c
index 4ddbc73c2a..56d8d4bf4a 100644
--- a/arm-semi.c
+++ b/arm-semi.c
@@ -112,57 +112,7 @@ static inline uint32_t set_swi_errno(CPUState *env, uint32_t code)
     return code;
 }
 
-static uint32_t softmmu_tget32(CPUState *env, uint32_t addr)
-{
-    uint32_t val;
-
-    cpu_memory_rw_debug(env, addr, (uint8_t *)&val, 4, 0);
-    return tswap32(val);
-}
-static uint32_t softmmu_tget8(CPUState *env, uint32_t addr)
-{
-    uint8_t val;
-
-    cpu_memory_rw_debug(env, addr, &val, 1, 0);
-    return val;
-}
-#define tget32(p) softmmu_tget32(env, p)
-#define tget8(p) softmmu_tget8(env, p)
-
-static void *softmmu_lock_user(CPUState *env, uint32_t addr, uint32_t len,
-                               int copy)
-{
-    char *p;
-    /* TODO: Make this something that isn't fixed size.  */
-    p = malloc(len);
-    if (copy)
-        cpu_memory_rw_debug(env, addr, p, len, 0);
-    return p;
-}
-#define lock_user(p, len, copy) softmmu_lock_user(env, p, len, copy)
-static char *softmmu_lock_user_string(CPUState *env, uint32_t addr)
-{
-    char *p;
-    char *s;
-    uint8_t c;
-    /* TODO: Make this something that isn't fixed size.  */
-    s = p = malloc(1024);
-    do {
-        cpu_memory_rw_debug(env, addr, &c, 1, 0);
-        addr++;
-        *(p++) = c;
-    } while (c);
-    return s;
-}
-#define lock_user_string(p) softmmu_lock_user_string(env, p)
-static void softmmu_unlock_user(CPUState *env, void *p, target_ulong addr,
-                                target_ulong len)
-{
-    if (len)
-        cpu_memory_rw_debug(env, addr, p, len, 1);
-    free(p);
-}
-#define unlock_user(s, args, len) softmmu_unlock_user(env, s, args, len)
+#include "softmmu-semi.h"
 #endif
 
 static target_ulong arm_semi_syscall_len;
diff --git a/gdbstub.c b/gdbstub.c
index 7dcaade66d..fd20c9ca7f 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -963,14 +963,16 @@ static void gdb_vm_stopped(void *opaque, int reason)
 
 /* Send a gdb syscall request.
    This accepts limited printf-style format specifiers, specifically:
-    %x - target_ulong argument printed in hex.
-    %s - string pointer (target_ulong) and length (int) pair.  */
+    %x  - target_ulong argument printed in hex.
+    %lx - 64-bit argument printed in hex.
+    %s  - string pointer (target_ulong) and length (int) pair.  */
 void gdb_do_syscall(gdb_syscall_complete_cb cb, char *fmt, ...)
 {
     va_list va;
     char buf[256];
     char *p;
     target_ulong addr;
+    uint64_t i64;
     GDBState *s;
 
     s = gdb_syscall_state;
@@ -993,11 +995,18 @@ void gdb_do_syscall(gdb_syscall_complete_cb cb, char *fmt, ...)
                 addr = va_arg(va, target_ulong);
                 p += sprintf(p, TARGET_FMT_lx, addr);
                 break;
+            case 'l':
+                if (*(fmt++) != 'x')
+                    goto bad_format;
+                i64 = va_arg(va, uint64_t);
+                p += sprintf(p, "%" PRIx64, i64);
+                break;
             case 's':
                 addr = va_arg(va, target_ulong);
                 p += sprintf(p, TARGET_FMT_lx "/%x", addr, va_arg(va, int));
                 break;
             default:
+            bad_format:
                 fprintf(stderr, "gdbstub: Bad syscall format string '%s'\n",
                         fmt - 1);
                 break;
diff --git a/linux-user/m68k-semi.c b/linux-user/m68k-semi.c
deleted file mode 100644
index 7f6dddaee4..0000000000
--- a/linux-user/m68k-semi.c
+++ /dev/null
@@ -1,216 +0,0 @@
-/*
- *  m68k/ColdFire Semihosting ssycall interface
- * 
- *  Copyright (c) 2005 CodeSourcery, LLC. Written by Paul Brook.
- *
- *  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 "qemu.h"
-
-#define HOSTED_EXIT  0
-#define HOSTED_PUTCHAR 1 /* Obsolete */
-#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 */
-};
-
-struct gdb_timeval {
-  gdb_time_t tv_sec;  /* second */
-  uint64_t tv_usec;   /* microsecond */
-};
-
-#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(struct m68k_gdb_stat *p, struct stat *s)
-{
-    p->gdb_st_dev = tswap16(s->st_dev);
-    p->gdb_st_ino = tswap16(s->st_ino);
-    p->gdb_st_mode = tswap32(s->st_mode);
-    p->gdb_st_nlink = tswap16(s->st_nlink);
-    p->gdb_st_uid = tswap16(s->st_uid);
-    p->gdb_st_gid = tswap16(s->st_gid);
-    p->gdb_st_rdev = tswap16(s->st_rdev);
-    p->gdb_st_size = tswap32(s->st_size);
-    p->gdb_st_atime = tswap32(s->st_atime);
-    p->gdb_st_mtime = tswap32(s->st_mtime);
-    p->gdb_st_ctime = tswap32(s->st_ctime);
-    p->gdb_st_blksize = tswap32(s->st_blksize);
-    p->gdb_st_blocks = tswap32(s->st_blocks);
-}
-
-static inline uint32_t check_err(CPUM68KState *env, uint32_t code)
-{
-  if (code == (uint32_t)-1) {
-      env->sr |= CCF_C;
-  } else {
-      env->sr &= ~CCF_C;
-      env->dregs[0] = code;
-  }
-  return code;
-}
-
-#define ARG(x) tswap32(args[x])
-void do_m68k_semihosting(CPUM68KState *env, int nr)
-{
-    uint32_t *args;
-
-    args = (uint32_t *)env->dregs[1];
-    switch (nr) {
-    case HOSTED_EXIT:
-        exit(env->dregs[0]);
-    case HOSTED_OPEN:
-        /* Assume name is NULL terminated.  */
-        check_err(env, open((char *)ARG(0), translate_openflags(ARG(2)),
-                            ARG(3)));
-        break;
-    case HOSTED_CLOSE:
-        {
-            /* Ignore attempts to close stdin/out/err.  */
-            int fd = ARG(0);
-            if (fd > 2)
-              check_err(env, close(fd));
-            else
-              check_err(env, 0);
-            break;
-        }
-    case HOSTED_READ:
-        check_err(env, read(ARG(0), (void *)ARG(1), ARG(2)));
-        break;
-    case HOSTED_WRITE:
-        check_err(env, write(ARG(0), (void *)ARG(1), ARG(2)));
-        break;
-    case HOSTED_LSEEK:
-        {
-            uint64_t off;
-            off = (uint32_t)ARG(2) | ((uint64_t)ARG(1) << 32);
-            check_err(env, lseek(ARG(0), off, ARG(3)));
-        }
-        break;
-    case HOSTED_RENAME:
-        /* Assume names are NULL terminated.  */
-        check_err(env, rename((char *)ARG(0), (char *)ARG(2)));
-        break;
-    case HOSTED_UNLINK:
-        /* Assume name is NULL terminated.  */
-        check_err(env, unlink((char *)ARG(0)));
-        break;
-    case HOSTED_STAT:
-        /* Assume name is NULL terminated.  */
-        {
-            struct stat s;
-            int rc;
-            rc = check_err(env, stat((char *)ARG(0), &s));
-            if (rc == 0) {
-                translate_stat((struct m68k_gdb_stat *)ARG(2), &s);
-            }
-        }
-        break;
-    case HOSTED_FSTAT:
-        {
-            struct stat s;
-            int rc;
-            rc = check_err(env, fstat(ARG(0), &s));
-            if (rc == 0) {
-                translate_stat((struct m68k_gdb_stat *)ARG(1), &s);
-            }
-        }
-        break;
-    case HOSTED_GETTIMEOFDAY:
-        {
-            struct timeval tv;
-            struct gdb_timeval *p;
-            int rc;
-            rc = check_err(env, gettimeofday(&tv, NULL));
-            if (rc != 0) {
-                p = (struct gdb_timeval *)ARG(0);
-                p->tv_sec = tswap32(tv.tv_sec);
-                p->tv_usec = tswap64(tv.tv_usec);
-            }
-        }
-        break;
-    case HOSTED_ISATTY:
-        check_err(env, isatty(ARG(0)));
-        break;
-    case HOSTED_SYSTEM:
-        /* Assume name is NULL terminated.  */
-        check_err(env, system((char *)ARG(0)));
-        break;
-    default:
-        cpu_abort(env, "Unsupported semihosting syscall %d\n", nr);
-    }
-}
diff --git a/linux-user/main.c b/linux-user/main.c
index 0f4dbdadff..45b03000d2 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -1502,9 +1502,9 @@ void cpu_loop(CPUM68KState *env)
                 }
             }
             break;
-        case EXCP_HALTED:
+        case EXCP_HALT_INSN:
             /* Semihosing syscall.  */
-            env->pc += 2;
+            env->pc += 4;
             do_m68k_semihosting(env, env->dregs[0]);
             break;
         case EXCP_LINEA:
@@ -1918,10 +1918,6 @@ int main(int argc, char **argv)
         for(i = 0; i < 16; i++) {
             env->regs[i] = regs->uregs[i];
         }
-        ts->stack_base = info->start_stack;
-        ts->heap_base = info->brk;
-        /* This will be filled in on the first SYS_HEAPINFO call.  */
-        ts->heap_limit = 0;
     }
 #elif defined(TARGET_SPARC)
     {
@@ -2049,6 +2045,13 @@ int main(int argc, char **argv)
 #error unsupported target CPU
 #endif
 
+#if defined(TARGET_ARM) || defined(TARGET_M68K)
+    ts->stack_base = info->start_stack;
+    ts->heap_base = info->brk;
+    /* This will be filled in on the first SYS_HEAPINFO call.  */
+    ts->heap_limit = 0;
+#endif
+
     if (gdbstub_port) {
         gdbserver_start (gdbstub_port);
         gdb_handlesig(env, 0);
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 31e29da7dc..076145e1af 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -62,10 +62,6 @@ typedef struct TaskState {
 #ifdef TARGET_ARM
     /* FPA state */
     FPA11 fpa;
-    /* Extra fields for semihosted binaries.  */
-    uint32_t stack_base;
-    uint32_t heap_base;
-    uint32_t heap_limit;
     int swi_errno;
 #endif
 #if defined(TARGET_I386) && !defined(TARGET_X86_64)
@@ -78,6 +74,12 @@ typedef struct TaskState {
 #ifdef TARGET_M68K
     int sim_syscalls;
 #endif
+#if defined(TARGET_ARM) || defined(TARGET_M68K)
+    /* Extra fields for semihosted binaries.  */
+    uint32_t stack_base;
+    uint32_t heap_base;
+    uint32_t heap_limit;
+#endif
     int used; /* non zero if used */
     struct image_info *info;
     uint8_t stack[0];
diff --git a/m68k-semi.c b/m68k-semi.c
new file mode 100644
index 0000000000..27bdce8e2f
--- /dev/null
+++ b/m68k-semi.c
@@ -0,0 +1,353 @@
+/*
+ *  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);
+    p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
+    p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
+    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 {
+            struct timeval tv;
+            struct gdb_timeval *p;
+            result = gettimeofday(&tv, NULL);
+            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);
+}
diff --git a/qemu-doc.texi b/qemu-doc.texi
index 544de3b009..81ddfb047b 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -715,7 +715,11 @@ Exit instead of rebooting.
 Start right away with a saved state (@code{loadvm} in monitor)
 
 @item -semihosting
-Enable "Angel" semihosting interface (ARM target machines only).
+Enable semihosting syscall emulation (ARM and M68K target machines only).
+
+On ARM this implements the "Angel" interface.
+On M68K this implements the "ColdFire GDB" interface used by libgloss.
+
 Note that this allows guest direct access to the host filesystem,
 so should only be used with trusted guest OS.
 @end table
diff --git a/target-m68k/cpu.h b/target-m68k/cpu.h
index c916ad7cd5..93080cfe12 100644
--- a/target-m68k/cpu.h
+++ b/target-m68k/cpu.h
@@ -51,6 +51,7 @@
 #define EXCP_ICE            13
 
 #define EXCP_RTE            0x100
+#define EXCP_HALT_INSN      0x101
 
 typedef struct CPUM68KState {
     uint32_t dregs[8];
@@ -148,6 +149,8 @@ void m68k_set_irq_level(CPUM68KState *env, int level, uint8_t vector);
 
 #define M68K_FPCR_PREC (1 << 6)
 
+void do_m68k_semihosting(CPUM68KState *env, int nr);
+
 #ifdef CONFIG_USER_ONLY
 /* Linux uses 8k pages.  */
 #define TARGET_PAGE_BITS 13
diff --git a/target-m68k/op.c b/target-m68k/op.c
index 6134bb018e..69d1fde9a7 100644
--- a/target-m68k/op.c
+++ b/target-m68k/op.c
@@ -383,8 +383,15 @@ OP(divs)
     FORCE_RET();
 }
 
+/* Halt is special because it may be a semihosting call.  */
 OP(halt)
 {
+    RAISE_EXCEPTION(EXCP_HALT_INSN);
+    FORCE_RET();
+}
+
+OP(stop)
+{
     env->halted = 1;
     RAISE_EXCEPTION(EXCP_HLT);
     FORCE_RET();
diff --git a/target-m68k/op_helper.c b/target-m68k/op_helper.c
index 7455e31659..f5593eca0c 100644
--- a/target-m68k/op_helper.c
+++ b/target-m68k/op_helper.c
@@ -28,6 +28,8 @@ void do_interrupt(int is_hw)
 
 #else
 
+extern int semihosting_enabled;
+
 #define MMUSUFFIX _mmu
 #define GETPC() (__builtin_return_address(0))
 
@@ -104,6 +106,20 @@ void do_interrupt(int is_hw)
             /* Return from an exception.  */
             do_rte();
             return;
+        case EXCP_HALT_INSN:
+            if (semihosting_enabled
+                    && (env->sr & SR_S) != 0
+                    && (env->pc & 3) == 0
+                    && lduw_code(env->pc - 4) == 0x4e71
+                    && ldl_code(env->pc) == 0x4e7bf000) {
+                env->pc += 4;
+                do_m68k_semihosting(env, env->dregs[0]);
+                return;
+            }
+            env->halted = 1;
+            env->exception_index = EXCP_HLT;
+            cpu_loop_exit();
+            return;
         }
         if (env->exception_index >= EXCP_TRAP0
             && env->exception_index <= EXCP_TRAP15) {
diff --git a/target-m68k/translate.c b/target-m68k/translate.c
index eff32867b8..d7162fea6f 100644
--- a/target-m68k/translate.c
+++ b/target-m68k/translate.c
@@ -1901,7 +1901,6 @@ DISAS_INSN(move_to_usp)
 
 DISAS_INSN(halt)
 {
-    gen_flush_cc_op(s);
     gen_jmp(s, gen_im32(s->pc));
     gen_op_halt();
 }
@@ -1919,7 +1918,8 @@ DISAS_INSN(stop)
     s->pc += 2;
 
     gen_set_sr_im(s, ext, 0);
-    disas_halt(s, insn);
+    gen_jmp(s, gen_im32(s->pc));
+    gen_op_stop();
 }
 
 DISAS_INSN(rte)
diff --git a/vl.c b/vl.c
index 24aef572f9..d23af87a71 100644
--- a/vl.c
+++ b/vl.c
@@ -6865,7 +6865,7 @@ const QEMUOption qemu_options[] = {
     { "show-cursor", 0, QEMU_OPTION_show_cursor },
     { "daemonize", 0, QEMU_OPTION_daemonize },
     { "option-rom", HAS_ARG, QEMU_OPTION_option_rom },
-#if defined(TARGET_ARM)
+#if defined(TARGET_ARM) || defined(TARGET_M68K)
     { "semihosting", 0, QEMU_OPTION_semihosting },
 #endif
     { "name", HAS_ARG, QEMU_OPTION_name },