Merge tag 'pull-semi-20220914' of https://gitlab.com/rth7680/qemu into staging

Convert m68k to semihosting/syscalls.h.
Convert nios2 to semihosting/syscalls.h.
Allow optional use of semihosting from userspace.

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* tag 'pull-semi-20220914' of https://gitlab.com/rth7680/qemu:
  target/riscv: Honour -semihosting-config userspace=on and enable=on
  target/xtensa: Honour -semihosting-config userspace=on
  target/nios2: Honour -semihosting-config userspace=on
  target/mips: Honour -semihosting-config userspace=on
  target/m68k: Honour -semihosting-config userspace=on
  target/arm: Honour -semihosting-config userspace=on
  semihosting: Allow optional use of semihosting from userspace
  target/m68k: Convert semihosting errno to gdb remote errno
  target/m68k: Use semihosting/syscalls.h
  target/nios2: Convert semihosting errno to gdb remote errno
  target/nios2: Use semihosting/syscalls.h

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

14 files changed, 182 insertions, 520 deletions

diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 163df8c..9bed336 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -2219,17 +2219,7 @@ static void disas_exc(DisasContext *s, uint32_t insn)
          * it is required for halting debug disabled: it will UNDEF.
          * Secondly, "HLT 0xf000" is the A64 semihosting syscall instruction.
          */
-        if (semihosting_enabled() && imm16 == 0xf000) {
-#ifndef CONFIG_USER_ONLY
-            /* In system mode, don't allow userspace access to semihosting,
-             * to provide some semblance of security (and for consistency
-             * with our 32-bit semihosting).
-             */
-            if (s->current_el == 0) {
-                unallocated_encoding(s);
-                break;
-            }
-#endif
+        if (semihosting_enabled(s->current_el == 0) && imm16 == 0xf000) {
             gen_exception_internal_insn(s, s->pc_curr, EXCP_SEMIHOST);
         } else {
             unallocated_encoding(s);
diff --git a/target/arm/translate.c b/target/arm/translate.c
index 9474e4b..5aaccbb 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -1169,10 +1169,7 @@ static inline void gen_hlt(DisasContext *s, int imm)
      * semihosting, to provide some semblance of security
      * (and for consistency with our 32-bit semihosting).
      */
-    if (semihosting_enabled() &&
-#ifndef CONFIG_USER_ONLY
-        s->current_el != 0 &&
-#endif
+    if (semihosting_enabled(s->current_el != 0) &&
         (imm == (s->thumb ? 0x3c : 0xf000))) {
         gen_exception_internal_insn(s, s->pc_curr, EXCP_SEMIHOST);
         return;
@@ -6556,10 +6553,7 @@ static bool trans_BKPT(DisasContext *s, arg_BKPT *a)
     /* BKPT is OK with ECI set and leaves it untouched */
     s->eci_handled = true;
     if (arm_dc_feature(s, ARM_FEATURE_M) &&
-        semihosting_enabled() &&
-#ifndef CONFIG_USER_ONLY
-        !IS_USER(s) &&
-#endif
+        semihosting_enabled(s->current_el == 0) &&
         (a->imm == 0xab)) {
         gen_exception_internal_insn(s, s->pc_curr, EXCP_SEMIHOST);
     } else {
@@ -8764,10 +8758,8 @@ static bool trans_SVC(DisasContext *s, arg_SVC *a)
 {
     const uint32_t semihost_imm = s->thumb ? 0xab : 0x123456;
 
-    if (!arm_dc_feature(s, ARM_FEATURE_M) && semihosting_enabled() &&
-#ifndef CONFIG_USER_ONLY
-        !IS_USER(s) &&
-#endif
+    if (!arm_dc_feature(s, ARM_FEATURE_M) &&
+        semihosting_enabled(s->current_el == 0) &&
         (a->imm == semihost_imm)) {
         gen_exception_internal_insn(s, s->pc_curr, EXCP_SEMIHOST);
     } else {
diff --git a/target/m68k/m68k-semi.c b/target/m68k/m68k-semi.c
index d0697dd..87b1314 100644
--- a/target/m68k/m68k-semi.c
+++ b/target/m68k/m68k-semi.c
@@ -21,6 +21,7 @@
 
 #include "cpu.h"
 #include "exec/gdbstub.h"
+#include "semihosting/syscalls.h"
 #include "semihosting/softmmu-uaccess.h"
 #include "hw/boards.h"
 #include "qemu/log.h"
@@ -40,54 +41,33 @@
 #define HOSTED_ISATTY 12
 #define HOSTED_SYSTEM 13
 
-static int translate_openflags(int flags)
+static int host_to_gdb_errno(int err)
 {
-    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(CPUM68KState *env, target_ulong addr, struct stat *s)
-{
-    struct gdb_stat *p;
-
-    p = lock_user(VERIFY_WRITE, addr, sizeof(struct gdb_stat), 0);
-    if (!p) {
-        /* FIXME - should this return an error code? */
-        return;
+#define E(X)  case E##X: return GDB_E##X
+    switch (err) {
+    E(PERM);
+    E(NOENT);
+    E(INTR);
+    E(BADF);
+    E(ACCES);
+    E(FAULT);
+    E(BUSY);
+    E(EXIST);
+    E(NODEV);
+    E(NOTDIR);
+    E(ISDIR);
+    E(INVAL);
+    E(NFILE);
+    E(MFILE);
+    E(FBIG);
+    E(NOSPC);
+    E(SPIPE);
+    E(ROFS);
+    E(NAMETOOLONG);
+    default:
+        return GDB_EUNKNOWN;
     }
-    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 gdb_stat));
+#undef E
 }
 
 static void m68k_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
@@ -97,7 +77,7 @@ static void m68k_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
 
     target_ulong args = env->dregs[1];
     if (put_user_u32(ret, args) ||
-        put_user_u32(err, args + 4)) {
+        put_user_u32(host_to_gdb_errno(err), args + 4)) {
         /*
          * The m68k 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.
@@ -116,7 +96,7 @@ static void m68k_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
     target_ulong args = env->dregs[1];
     if (put_user_u32(ret >> 32, args) ||
         put_user_u32(ret, args + 4) ||
-        put_user_u32(err, args + 8)) {
+        put_user_u32(host_to_gdb_errno(err), args + 8)) {
         /* No way to report this via m68k semihosting ABI; just log it */
         qemu_log_mask(LOG_GUEST_ERROR, "m68k-semihosting: return value "
                       "discarded because argument block not writable\n");
@@ -129,248 +109,109 @@ static void m68k_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
  */
 #define GET_ARG(n) do {                                 \
     if (get_user_ual(arg ## n, args + (n) * 4)) {       \
-        result = -1;                                    \
-        errno = EFAULT;                                 \
         goto failed;                                    \
     }                                                   \
 } while (0)
 
+#define GET_ARG64(n) do {                               \
+    if (get_user_ual(arg ## n, args + (n) * 4)) {       \
+        goto failed64;                                  \
+    }                                                   \
+} while (0)
+
+
 void do_m68k_semihosting(CPUM68KState *env, int nr)
 {
     CPUState *cs = env_cpu(env);
     uint32_t args;
     target_ulong arg0, arg1, arg2, arg3;
-    void *p;
-    void *q;
-    uint32_t len;
-    uint32_t result;
 
     args = env->dregs[1];
     switch (nr) {
     case HOSTED_EXIT:
         gdb_exit(env->dregs[0]);
         exit(env->dregs[0]);
+
     case HOSTED_OPEN:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
         GET_ARG(3);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "open,%s,%x,%x", arg0, (int)arg1,
-                           arg2, arg3);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = open(p, translate_openflags(arg2), arg3);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_open(cs, m68k_semi_u32_cb, arg0, arg1, arg2, arg3);
         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(m68k_semi_u32_cb, "close,%x", arg0);
-                    return;
-                } else {
-                    result = close(fd);
-                }
-            } else {
-                result = 0;
-            }
-            break;
-        }
+        GET_ARG(0);
+        semihost_sys_close(cs, m68k_semi_u32_cb, arg0);
+        break;
+
     case HOSTED_READ:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        len = arg2;
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "read,%x,%x,%x",
-                           arg0, arg1, len);
-            return;
-        } else {
-            p = lock_user(VERIFY_WRITE, arg1, len, 0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = read(arg0, p, len);
-                unlock_user(p, arg1, len);
-            }
-        }
+        semihost_sys_read(cs, m68k_semi_u32_cb, arg0, arg1, arg2);
         break;
+
     case HOSTED_WRITE:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        len = arg2;
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "write,%x,%x,%x",
-                           arg0, arg1, len);
-            return;
-        } else {
-            p = lock_user(VERIFY_READ, arg1, len, 1);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = write(arg0, p, len);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_write(cs, m68k_semi_u32_cb, arg0, arg1, arg2);
         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()) {
-                gdb_do_syscall(m68k_semi_u64_cb, "fseek,%x,%lx,%x",
-                               arg0, off, arg3);
-            } else {
-                off = lseek(arg0, off, arg3);
-                m68k_semi_u64_cb(cs, off, errno);
-            }
-            return;
-        }
+        GET_ARG64(0);
+        GET_ARG64(1);
+        GET_ARG64(2);
+        GET_ARG64(3);
+        semihost_sys_lseek(cs, m68k_semi_u64_cb, arg0,
+                           deposit64(arg2, arg1, 32, 32), arg3);
+        break;
+
     case HOSTED_RENAME:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
         GET_ARG(3);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_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) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = rename(p, q);
-            }
-            unlock_user(p, arg0, 0);
-            unlock_user(q, arg2, 0);
-        }
+        semihost_sys_rename(cs, m68k_semi_u32_cb, arg0, arg1, arg2, arg3);
         break;
+
     case HOSTED_UNLINK:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "unlink,%s",
-                           arg0, (int)arg1);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = unlink(p);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_remove(cs, m68k_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_STAT:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "stat,%s,%x",
-                           arg0, (int)arg1, arg2);
-            return;
-        } else {
-            struct stat s;
-            p = lock_user_string(arg0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = stat(p, &s);
-                unlock_user(p, arg0, 0);
-            }
-            if (result == 0) {
-                translate_stat(env, arg2, &s);
-            }
-        }
+        semihost_sys_stat(cs, m68k_semi_u32_cb, arg0, arg1, arg2);
         break;
+
     case HOSTED_FSTAT:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "fstat,%x,%x",
-                           arg0, arg1);
-            return;
-        } else {
-            struct stat s;
-            result = fstat(arg0, &s);
-            if (result == 0) {
-                translate_stat(env, arg1, &s);
-            }
-        }
+        semihost_sys_fstat(cs, m68k_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_GETTIMEOFDAY:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "gettimeofday,%x,%x",
-                           arg0, arg1);
-            return;
-        } else {
-            struct gdb_timeval *p;
-            int64_t rt = g_get_real_time();
-            p = lock_user(VERIFY_WRITE, arg0, sizeof(struct gdb_timeval), 0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = 0;
-                p->tv_sec = cpu_to_be32(rt / G_USEC_PER_SEC);
-                p->tv_usec = cpu_to_be64(rt % G_USEC_PER_SEC);
-                unlock_user(p, arg0, sizeof(struct gdb_timeval));
-            }
-        }
+        semihost_sys_gettimeofday(cs, m68k_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_ISATTY:
         GET_ARG(0);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "isatty,%x", arg0);
-            return;
-        } else {
-            result = isatty(arg0);
-        }
+        semihost_sys_isatty(cs, m68k_semi_u32_cb, arg0);
         break;
+
     case HOSTED_SYSTEM:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "system,%s",
-                           arg0, (int)arg1);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = system(p);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_system(cs, m68k_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_INIT_SIM:
         /*
          * FIXME: This is wrong for boards where RAM does not start at
@@ -379,10 +220,15 @@ void do_m68k_semihosting(CPUM68KState *env, int nr)
         env->dregs[1] = current_machine->ram_size;
         env->aregs[7] = current_machine->ram_size;
         return;
+
     default:
         cpu_abort(env_cpu(env), "Unsupported semihosting syscall %d\n", nr);
-        result = 0;
+
+    failed:
+        m68k_semi_u32_cb(cs, -1, EFAULT);
+        break;
+    failed64:
+        m68k_semi_u64_cb(cs, -1, EFAULT);
+        break;
     }
-failed:
-    m68k_semi_u32_cb(cs, result, errno);
 }
diff --git a/target/m68k/op_helper.c b/target/m68k/op_helper.c
index d9937ca..a96a034 100644
--- a/target/m68k/op_helper.c
+++ b/target/m68k/op_helper.c
@@ -203,8 +203,7 @@ static void cf_interrupt_all(CPUM68KState *env, int is_hw)
             cf_rte(env);
             return;
         case EXCP_HALT_INSN:
-            if (semihosting_enabled()
-                    && (env->sr & SR_S) != 0
+            if (semihosting_enabled((env->sr & SR_S) == 0)
                     && (env->pc & 3) == 0
                     && cpu_lduw_code(env, env->pc - 4) == 0x4e71
                     && cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
diff --git a/target/mips/tcg/micromips_translate.c.inc b/target/mips/tcg/micromips_translate.c.inc
index b2c696f..632895c 100644
--- a/target/mips/tcg/micromips_translate.c.inc
+++ b/target/mips/tcg/micromips_translate.c.inc
@@ -825,7 +825,7 @@ static void gen_pool16c_insn(DisasContext *ctx)
         generate_exception_break(ctx, extract32(ctx->opcode, 0, 4));
         break;
     case SDBBP16:
-        if (is_uhi(extract32(ctx->opcode, 0, 4))) {
+        if (is_uhi(ctx, extract32(ctx->opcode, 0, 4))) {
             ctx->base.is_jmp = DISAS_SEMIHOST;
         } else {
             /*
@@ -941,7 +941,7 @@ static void gen_pool16c_r6_insn(DisasContext *ctx)
             break;
         case R6_SDBBP16:
             /* SDBBP16 */
-            if (is_uhi(extract32(ctx->opcode, 6, 4))) {
+            if (is_uhi(ctx, extract32(ctx->opcode, 6, 4))) {
                 ctx->base.is_jmp = DISAS_SEMIHOST;
             } else {
                 if (ctx->hflags & MIPS_HFLAG_SBRI) {
@@ -1310,7 +1310,7 @@ static void gen_pool32axf(CPUMIPSState *env, DisasContext *ctx, int rt, int rs)
             generate_exception_end(ctx, EXCP_SYSCALL);
             break;
         case SDBBP:
-            if (is_uhi(extract32(ctx->opcode, 16, 10))) {
+            if (is_uhi(ctx, extract32(ctx->opcode, 16, 10))) {
                 ctx->base.is_jmp = DISAS_SEMIHOST;
             } else {
                 check_insn(ctx, ISA_MIPS_R1);
diff --git a/target/mips/tcg/mips16e_translate.c.inc b/target/mips/tcg/mips16e_translate.c.inc
index 7568933..918b15d 100644
--- a/target/mips/tcg/mips16e_translate.c.inc
+++ b/target/mips/tcg/mips16e_translate.c.inc
@@ -951,7 +951,7 @@ static int decode_ase_mips16e(CPUMIPSState *env, DisasContext *ctx)
             }
             break;
         case RR_SDBBP:
-            if (is_uhi(extract32(ctx->opcode, 5, 6))) {
+            if (is_uhi(ctx, extract32(ctx->opcode, 5, 6))) {
                 ctx->base.is_jmp = DISAS_SEMIHOST;
             } else {
                 /*
diff --git a/target/mips/tcg/nanomips_translate.c.inc b/target/mips/tcg/nanomips_translate.c.inc
index b3aff22..812c111 100644
--- a/target/mips/tcg/nanomips_translate.c.inc
+++ b/target/mips/tcg/nanomips_translate.c.inc
@@ -3694,7 +3694,7 @@ static int decode_nanomips_32_48_opc(CPUMIPSState *env, DisasContext *ctx)
                 generate_exception_end(ctx, EXCP_BREAK);
                 break;
             case NM_SDBBP:
-                if (is_uhi(extract32(ctx->opcode, 0, 19))) {
+                if (is_uhi(ctx, extract32(ctx->opcode, 0, 19))) {
                     ctx->base.is_jmp = DISAS_SEMIHOST;
                 } else {
                     if (ctx->hflags & MIPS_HFLAG_SBRI) {
@@ -4633,7 +4633,7 @@ static int decode_isa_nanomips(CPUMIPSState *env, DisasContext *ctx)
                 generate_exception_end(ctx, EXCP_BREAK);
                 break;
             case NM_SDBBP16:
-                if (is_uhi(extract32(ctx->opcode, 0, 3))) {
+                if (is_uhi(ctx, extract32(ctx->opcode, 0, 3))) {
                     ctx->base.is_jmp = DISAS_SEMIHOST;
                 } else {
                     if (ctx->hflags & MIPS_HFLAG_SBRI) {
diff --git a/target/mips/tcg/translate.c b/target/mips/tcg/translate.c
index 0d936e2..c3f92ea 100644
--- a/target/mips/tcg/translate.c
+++ b/target/mips/tcg/translate.c
@@ -12082,12 +12082,13 @@ static void gen_cache_operation(DisasContext *ctx, uint32_t op, int base,
     tcg_temp_free_i32(t0);
 }
 
-static inline bool is_uhi(int sdbbp_code)
+static inline bool is_uhi(DisasContext *ctx, int sdbbp_code)
 {
 #ifdef CONFIG_USER_ONLY
     return false;
 #else
-    return semihosting_enabled() && sdbbp_code == 1;
+    bool is_user = (ctx->hflags & MIPS_HFLAG_KSU) == MIPS_HFLAG_UM;
+    return semihosting_enabled(is_user) && sdbbp_code == 1;
 #endif
 }
 
@@ -13898,7 +13899,7 @@ static void decode_opc_special_r6(CPUMIPSState *env, DisasContext *ctx)
         }
         break;
     case R6_OPC_SDBBP:
-        if (is_uhi(extract32(ctx->opcode, 6, 20))) {
+        if (is_uhi(ctx, extract32(ctx->opcode, 6, 20))) {
             ctx->base.is_jmp = DISAS_SEMIHOST;
         } else {
             if (ctx->hflags & MIPS_HFLAG_SBRI) {
@@ -14310,7 +14311,7 @@ static void decode_opc_special2_legacy(CPUMIPSState *env, DisasContext *ctx)
         gen_cl(ctx, op1, rd, rs);
         break;
     case OPC_SDBBP:
-        if (is_uhi(extract32(ctx->opcode, 6, 20))) {
+        if (is_uhi(ctx, extract32(ctx->opcode, 6, 20))) {
             ctx->base.is_jmp = DISAS_SEMIHOST;
         } else {
             /*
diff --git a/target/nios2/nios2-semi.c b/target/nios2/nios2-semi.c
index 55061bb..f76e858 100644
--- a/target/nios2/nios2-semi.c
+++ b/target/nios2/nios2-semi.c
@@ -24,6 +24,7 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "exec/gdbstub.h"
+#include "semihosting/syscalls.h"
 #include "semihosting/softmmu-uaccess.h"
 #include "qemu/log.h"
 
@@ -42,65 +43,33 @@
 #define HOSTED_ISATTY 12
 #define HOSTED_SYSTEM 13
 
-static int translate_openflags(int flags)
+static int host_to_gdb_errno(int err)
 {
-    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 gdb_stat *p;
-
-    p = lock_user(VERIFY_WRITE, addr, sizeof(struct gdb_stat), 0);
-
-    if (!p) {
-        return false;
+#define E(X)  case E##X: return GDB_E##X
+    switch (err) {
+    E(PERM);
+    E(NOENT);
+    E(INTR);
+    E(BADF);
+    E(ACCES);
+    E(FAULT);
+    E(BUSY);
+    E(EXIST);
+    E(NODEV);
+    E(NOTDIR);
+    E(ISDIR);
+    E(INVAL);
+    E(NFILE);
+    E(MFILE);
+    E(FBIG);
+    E(NOSPC);
+    E(SPIPE);
+    E(ROFS);
+    E(NAMETOOLONG);
+    default:
+        return GDB_EUNKNOWN;
     }
-    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 gdb_stat));
-    return true;
+#undef E
 }
 
 static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
@@ -110,7 +79,7 @@ static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
     target_ulong args = env->regs[R_ARG1];
 
     if (put_user_u32(ret, args) ||
-        put_user_u32(err, args + 4)) {
+        put_user_u32(host_to_gdb_errno(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.
@@ -129,7 +98,7 @@ static void nios2_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
 
     if (put_user_u32(ret >> 32, args) ||
         put_user_u32(ret, args + 4) ||
-        put_user_u32(err, args + 8)) {
+        put_user_u32(host_to_gdb_errno(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");
@@ -142,22 +111,22 @@ static void nios2_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
  */
 #define GET_ARG(n) do {                                 \
     if (get_user_ual(arg ## n, args + (n) * 4)) {       \
-        result = -1;                                    \
-        errno = EFAULT;                                 \
         goto failed;                                    \
     }                                                   \
 } while (0)
 
+#define GET_ARG64(n) do {                               \
+    if (get_user_ual(arg ## n, args + (n) * 4)) {       \
+        goto failed64;                                  \
+    }                                                   \
+} while (0)
+
 void do_nios2_semihosting(CPUNios2State *env)
 {
     CPUState *cs = env_cpu(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];
@@ -165,234 +134,98 @@ void do_nios2_semihosting(CPUNios2State *env)
     case HOSTED_EXIT:
         gdb_exit(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_u32_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);
-            }
-        }
+        semihost_sys_open(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
         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_u32_cb, "close,%x", arg0);
-                    return;
-                } else {
-                    result = close(fd);
-                }
-            } else {
-                result = 0;
-            }
-            break;
-        }
+        GET_ARG(0);
+        semihost_sys_close(cs, nios2_semi_u32_cb, arg0);
+        break;
+
     case HOSTED_READ:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        len = arg2;
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_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);
-            }
-        }
+        semihost_sys_read(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
         break;
+
     case HOSTED_WRITE:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        len = arg2;
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_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);
-            }
-        }
+        semihost_sys_write(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
         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()) {
-                gdb_do_syscall(nios2_semi_u64_cb, "lseek,%x,%lx,%x",
-                               arg0, off, arg3);
-            } else {
-                off = lseek(arg0, off, arg3);
-                nios2_semi_u64_cb(cs, off, errno);
-            }
-            return;
-        }
+        GET_ARG64(0);
+        GET_ARG64(1);
+        GET_ARG64(2);
+        GET_ARG64(3);
+        semihost_sys_lseek(cs, nios2_semi_u64_cb, arg0,
+                           deposit64(arg2, arg1, 32, 32), arg3);
+        break;
+
     case HOSTED_RENAME:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
         GET_ARG(3);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_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);
-        }
+        semihost_sys_rename(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
         break;
+
     case HOSTED_UNLINK:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_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);
-            }
-        }
+        semihost_sys_remove(cs, nios2_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_STAT:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_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;
-            }
-        }
+        semihost_sys_stat(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
         break;
+
     case HOSTED_FSTAT:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_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;
-            }
-        }
+        semihost_sys_fstat(cs, nios2_semi_u32_cb, arg0, arg1);
         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_u32_cb, "gettimeofday,%x,%x",
-                           arg0, 0);
-            return;
-        } else {
-            struct gdb_timeval *p;
-            int64_t rt = g_get_real_time();
-            p = lock_user(VERIFY_WRITE, arg0, sizeof(struct gdb_timeval), 0);
-            if (!p) {
-                result = -1;
-                errno = EFAULT;
-            } else {
-                result = 0;
-                p->tv_sec = cpu_to_be32(rt / G_USEC_PER_SEC);
-                p->tv_usec = cpu_to_be64(rt % G_USEC_PER_SEC);
-                unlock_user(p, arg0, sizeof(struct gdb_timeval));
-            }
-        }
+        GET_ARG(1);
+        semihost_sys_gettimeofday(cs, nios2_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_ISATTY:
         GET_ARG(0);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_cb, "isatty,%x", arg0);
-            return;
-        } else {
-            result = isatty(arg0);
-        }
+        semihost_sys_isatty(cs, nios2_semi_u32_cb, arg0);
         break;
+
     case HOSTED_SYSTEM:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_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);
-            }
-        }
+        semihost_sys_system(cs, nios2_semi_u32_cb, arg0, arg1);
         break;
+
     default:
         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
                       "semihosting syscall %d\n", nr);
-        result = 0;
+        nios2_semi_u32_cb(cs, -1, ENOSYS);
+        break;
+
+    failed:
+        nios2_semi_u32_cb(cs, -1, EFAULT);
+        break;
+    failed64:
+        nios2_semi_u64_cb(cs, -1, EFAULT);
+        break;
     }
-failed:
-    nios2_semi_u32_cb(cs, result, errno);
 }
diff --git a/target/nios2/translate.c b/target/nios2/translate.c
index c588e8e..8dc0a32 100644
--- a/target/nios2/translate.c
+++ b/target/nios2/translate.c
@@ -817,8 +817,9 @@ static void gen_break(DisasContext *dc, uint32_t code, uint32_t flags)
 {
 #ifndef CONFIG_USER_ONLY
     /* The semihosting instruction is "break 1".  */
+    bool is_user = FIELD_EX32(dc->tb_flags, TBFLAGS, U);
     R_TYPE(instr, code);
-    if (semihosting_enabled() && instr.imm5 == 1) {
+    if (semihosting_enabled(is_user) && instr.imm5 == 1) {
         t_gen_helper_raise_exception(dc, EXCP_SEMIHOST);
         return;
     }
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 67e4c0e..278d163 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -1589,12 +1589,9 @@ void riscv_cpu_do_interrupt(CPUState *cs)
     target_ulong mtval2 = 0;
 
     if  (cause == RISCV_EXCP_SEMIHOST) {
-        if (env->priv >= PRV_S) {
-            do_common_semihosting(cs);
-            env->pc += 4;
-            return;
-        }
-        cause = RISCV_EXCP_BREAKPOINT;
+        do_common_semihosting(cs);
+        env->pc += 4;
+        return;
     }
 
     if (!async) {
diff --git a/target/riscv/insn_trans/trans_privileged.c.inc b/target/riscv/insn_trans/trans_privileged.c.inc
index 46f96ad..3281408 100644
--- a/target/riscv/insn_trans/trans_privileged.c.inc
+++ b/target/riscv/insn_trans/trans_privileged.c.inc
@@ -52,7 +52,8 @@ static bool trans_ebreak(DisasContext *ctx, arg_ebreak *a)
      * that no exception will be raised when fetching them.
      */
 
-    if ((pre_addr & TARGET_PAGE_MASK) == (post_addr & TARGET_PAGE_MASK)) {
+    if (semihosting_enabled(ctx->mem_idx < PRV_S) &&
+        (pre_addr & TARGET_PAGE_MASK) == (post_addr & TARGET_PAGE_MASK)) {
         pre    = opcode_at(&ctx->base, pre_addr);
         ebreak = opcode_at(&ctx->base, ebreak_addr);
         post   = opcode_at(&ctx->base, post_addr);
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 8925a44..db123da 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -28,6 +28,7 @@
 
 #include "exec/translator.h"
 #include "exec/log.h"
+#include "semihosting/semihost.h"
 
 #include "instmap.h"
 #include "internals.h"
diff --git a/target/xtensa/translate.c b/target/xtensa/translate.c
index 8b864ef..bdd4690 100644
--- a/target/xtensa/translate.c
+++ b/target/xtensa/translate.c
@@ -2362,13 +2362,14 @@ static uint32_t test_exceptions_simcall(DisasContext *dc,
                                         const OpcodeArg arg[],
                                         const uint32_t par[])
 {
+    bool is_semi = semihosting_enabled(dc->cring != 0);
 #ifdef CONFIG_USER_ONLY
     bool ill = true;
 #else
     /* Between RE.2 and RE.3 simcall opcode's become nop for the hardware. */
-    bool ill = dc->config->hw_version <= 250002 && !semihosting_enabled();
+    bool ill = dc->config->hw_version <= 250002 && !is_semi;
 #endif
-    if (ill || !semihosting_enabled()) {
+    if (ill || !is_semi) {
         qemu_log_mask(LOG_GUEST_ERROR, "SIMCALL but semihosting is disabled\n");
     }
     return ill ? XTENSA_OP_ILL : 0;
@@ -2378,7 +2379,7 @@ static void translate_simcall(DisasContext *dc, const OpcodeArg arg[],
                               const uint32_t par[])
 {
 #ifndef CONFIG_USER_ONLY
-    if (semihosting_enabled()) {
+    if (semihosting_enabled(dc->cring != 0)) {
         gen_helper_simcall(cpu_env);
     }
 #endif