diff --git a/target/mips/tcg/sysemu/mips-semi.c b/target/mips/tcg/sysemu/mips-semi.c
index 93c9d3d0b3..5b78cf21a7 100644
--- a/target/mips/tcg/sysemu/mips-semi.c
+++ b/target/mips/tcg/sysemu/mips-semi.c
@@ -20,9 +20,11 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "qemu/log.h"
+#include "exec/gdbstub.h"
 #include "semihosting/softmmu-uaccess.h"
 #include "semihosting/semihost.h"
 #include "semihosting/console.h"
+#include "semihosting/syscalls.h"
 #include "internal.h"
 
 typedef enum UHIOp {
@@ -121,101 +123,79 @@ static void report_fault(CPUMIPSState *env)
     abort();
 }
 
-static int errno_mips(int host_errno)
+static void uhi_cb(CPUState *cs, uint64_t ret, int err)
 {
-    /* Errno values taken from asm-mips/errno.h */
-    switch (host_errno) {
-    case 0:             return 0;
-    case ENAMETOOLONG:  return 78;
-#ifdef EOVERFLOW
-    case EOVERFLOW:     return 79;
-#endif
-#ifdef ELOOP
-    case ELOOP:         return 90;
-#endif
-    default:            return EINVAL;
-    }
-}
+    CPUMIPSState *env = cs->env_ptr;
 
-static int copy_stat_to_target(CPUMIPSState *env, const struct stat *src,
-                               target_ulong vaddr)
-{
-    hwaddr len = sizeof(struct UHIStat);
-    UHIStat *dst = lock_user(VERIFY_WRITE, vaddr, len, 0);
-    if (!dst) {
+#define E(N) case E##N: err = UHI_E##N; break
+
+    switch (err) {
+    case 0:
+        break;
+    E(PERM);
+    E(NOENT);
+    E(INTR);
+    E(BADF);
+    E(BUSY);
+    E(EXIST);
+    E(NOTDIR);
+    E(ISDIR);
+    E(INVAL);
+    E(NFILE);
+    E(MFILE);
+    E(FBIG);
+    E(NOSPC);
+    E(SPIPE);
+    E(ROFS);
+    E(NAMETOOLONG);
+    default:
+        err = UHI_EINVAL;
+        break;
+    case EFAULT:
         report_fault(env);
     }
 
-    dst->uhi_st_dev = tswap16(src->st_dev);
-    dst->uhi_st_ino = tswap16(src->st_ino);
-    dst->uhi_st_mode = tswap32(src->st_mode);
-    dst->uhi_st_nlink = tswap16(src->st_nlink);
-    dst->uhi_st_uid = tswap16(src->st_uid);
-    dst->uhi_st_gid = tswap16(src->st_gid);
-    dst->uhi_st_rdev = tswap16(src->st_rdev);
-    dst->uhi_st_size = tswap64(src->st_size);
-    dst->uhi_st_atime = tswap64(src->st_atime);
-    dst->uhi_st_mtime = tswap64(src->st_mtime);
-    dst->uhi_st_ctime = tswap64(src->st_ctime);
-#ifdef _WIN32
-    dst->uhi_st_blksize = 0;
-    dst->uhi_st_blocks = 0;
-#else
-    dst->uhi_st_blksize = tswap64(src->st_blksize);
-    dst->uhi_st_blocks = tswap64(src->st_blocks);
-#endif
-    unlock_user(dst, vaddr, len);
-    return 0;
+#undef E
+
+    env->active_tc.gpr[2] = ret;
+    env->active_tc.gpr[3] = err;
 }
 
-static int get_open_flags(target_ulong target_flags)
+static void uhi_fstat_cb(CPUState *cs, uint64_t ret, int err)
 {
-    int open_flags = 0;
+    QEMU_BUILD_BUG_ON(sizeof(UHIStat) < sizeof(struct gdb_stat));
 
-    if (target_flags & UHIOpen_RDWR) {
-        open_flags |= O_RDWR;
-    } else if (target_flags & UHIOpen_WRONLY) {
-        open_flags |= O_WRONLY;
-    } else {
-        open_flags |= O_RDONLY;
+    if (!err) {
+        CPUMIPSState *env = cs->env_ptr;
+        target_ulong addr = env->active_tc.gpr[5];
+        UHIStat *dst = lock_user(VERIFY_WRITE, addr, sizeof(UHIStat), 1);
+        struct gdb_stat s;
+
+        if (!dst) {
+            report_fault(env);
+        }
+
+        memcpy(&s, dst, sizeof(struct gdb_stat));
+        memset(dst, 0, sizeof(UHIStat));
+
+        dst->uhi_st_dev = tswap16(be32_to_cpu(s.gdb_st_dev));
+        dst->uhi_st_ino = tswap16(be32_to_cpu(s.gdb_st_ino));
+        dst->uhi_st_mode = tswap32(be32_to_cpu(s.gdb_st_mode));
+        dst->uhi_st_nlink = tswap16(be32_to_cpu(s.gdb_st_nlink));
+        dst->uhi_st_uid = tswap16(be32_to_cpu(s.gdb_st_uid));
+        dst->uhi_st_gid = tswap16(be32_to_cpu(s.gdb_st_gid));
+        dst->uhi_st_rdev = tswap16(be32_to_cpu(s.gdb_st_rdev));
+        dst->uhi_st_size = tswap64(be64_to_cpu(s.gdb_st_size));
+        dst->uhi_st_atime = tswap64(be32_to_cpu(s.gdb_st_atime));
+        dst->uhi_st_mtime = tswap64(be32_to_cpu(s.gdb_st_mtime));
+        dst->uhi_st_ctime = tswap64(be32_to_cpu(s.gdb_st_ctime));
+        dst->uhi_st_blksize = tswap64(be64_to_cpu(s.gdb_st_blksize));
+        dst->uhi_st_blocks = tswap64(be64_to_cpu(s.gdb_st_blocks));
+
+        unlock_user(dst, addr, sizeof(UHIStat));
     }
 
-    open_flags |= (target_flags & UHIOpen_APPEND) ? O_APPEND : 0;
-    open_flags |= (target_flags & UHIOpen_CREAT)  ? O_CREAT  : 0;
-    open_flags |= (target_flags & UHIOpen_TRUNC)  ? O_TRUNC  : 0;
-    open_flags |= (target_flags & UHIOpen_EXCL)   ? O_EXCL   : 0;
-
-    return open_flags;
-}
-
-static int write_to_file(CPUMIPSState *env, target_ulong fd,
-                         target_ulong vaddr, target_ulong len)
-{
-    int num_of_bytes;
-    void *dst = lock_user(VERIFY_READ, vaddr, len, 1);
-    if (!dst) {
-        report_fault(env);
-    }
-
-    num_of_bytes = write(fd, dst, len);
-
-    unlock_user(dst, vaddr, 0);
-    return num_of_bytes;
-}
-
-static int read_from_file(CPUMIPSState *env, target_ulong fd,
-                          target_ulong vaddr, target_ulong len)
-{
-    int num_of_bytes;
-    void *dst = lock_user(VERIFY_WRITE, vaddr, len, 0);
-    if (!dst) {
-        report_fault(env);
-    }
-
-    num_of_bytes = read(fd, dst, len);
-
-    unlock_user(dst, vaddr, len);
-    return num_of_bytes;
+    uhi_cb(cs, ret, err);
 }
 
 static int copy_argn_to_target(CPUMIPSState *env, int arg_num,
@@ -260,68 +240,59 @@ static int copy_argn_to_target(CPUMIPSState *env, int arg_num,
 
 void mips_semihosting(CPUMIPSState *env)
 {
+    CPUState *cs = env_cpu(env);
     target_ulong *gpr = env->active_tc.gpr;
     const UHIOp op = gpr[25];
     char *p, *p2;
 
     switch (op) {
     case UHI_exit:
-        qemu_log("UHI(%d): exit(%d)\n", op, (int)gpr[4]);
+        gdb_exit(gpr[4]);
         exit(gpr[4]);
+
     case UHI_open:
-        GET_TARGET_STRING(p, gpr[4]);
-        if (!strcmp("/dev/stdin", p)) {
-            gpr[2] = 0;
-        } else if (!strcmp("/dev/stdout", p)) {
-            gpr[2] = 1;
-        } else if (!strcmp("/dev/stderr", p)) {
-            gpr[2] = 2;
-        } else {
-            gpr[2] = open(p, get_open_flags(gpr[5]), gpr[6]);
-            gpr[3] = errno_mips(errno);
+        {
+            int ret = -1;
+
+            GET_TARGET_STRING(p, gpr[4]);
+            if (!strcmp("/dev/stdin", p)) {
+                ret = 0;
+            } else if (!strcmp("/dev/stdout", p)) {
+                ret = 1;
+            } else if (!strcmp("/dev/stderr", p)) {
+                ret = 2;
+            }
+            FREE_TARGET_STRING(p, gpr[4]);
+
+            /* FIXME: reusing a guest fd doesn't seem correct. */
+            if (ret >= 0) {
+                gpr[2] = ret;
+                break;
+            }
+
+            semihost_sys_open(cs, uhi_cb, gpr[4], 0, gpr[5], gpr[6]);
         }
-        FREE_TARGET_STRING(p, gpr[4]);
         break;
+
     case UHI_close:
-        if (gpr[4] < 3) {
-            /* ignore closing stdin/stdout/stderr */
-            gpr[2] = 0;
-            return;
-        }
-        gpr[2] = close(gpr[4]);
-        gpr[3] = errno_mips(errno);
+        semihost_sys_close(cs, uhi_cb, gpr[4]);
         break;
     case UHI_read:
-        gpr[2] = read_from_file(env, gpr[4], gpr[5], gpr[6]);
-        gpr[3] = errno_mips(errno);
+        semihost_sys_read(cs, uhi_cb, gpr[4], gpr[5], gpr[6]);
         break;
     case UHI_write:
-        gpr[2] = write_to_file(env, gpr[4], gpr[5], gpr[6]);
-        gpr[3] = errno_mips(errno);
+        semihost_sys_write(cs, uhi_cb, gpr[4], gpr[5], gpr[6]);
         break;
     case UHI_lseek:
-        gpr[2] = lseek(gpr[4], gpr[5], gpr[6]);
-        gpr[3] = errno_mips(errno);
+        semihost_sys_lseek(cs, uhi_cb, gpr[4], gpr[5], gpr[6]);
         break;
     case UHI_unlink:
-        GET_TARGET_STRING(p, gpr[4]);
-        gpr[2] = remove(p);
-        gpr[3] = errno_mips(errno);
-        FREE_TARGET_STRING(p, gpr[4]);
+        semihost_sys_remove(cs, uhi_cb, gpr[4], 0);
         break;
     case UHI_fstat:
-        {
-            struct stat sbuf;
-            memset(&sbuf, 0, sizeof(sbuf));
-            gpr[2] = fstat(gpr[4], &sbuf);
-            gpr[3] = errno_mips(errno);
-            if (gpr[2]) {
-                return;
-            }
-            gpr[2] = copy_stat_to_target(env, &sbuf, gpr[5]);
-            gpr[3] = errno_mips(errno);
-        }
+        semihost_sys_fstat(cs, uhi_fstat_cb, gpr[4], gpr[5]);
         break;
+
     case UHI_argc:
         gpr[2] = semihosting_get_argc();
         break;
