target/arm: Honour -semihosting-config userspace=on

Honour the commandline -semihosting-config userspace=on option,
instead of never permitting userspace semihosting calls in system
emulation mode, by passing the correct value to the is_userspace
argument of semihosting_enabled(), instead of manually checking and
always forbidding semihosting if the guest is in userspace and this
isn't the linux-user build.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Message-Id: <20220822141230.3658237-3-peter.maydell@linaro.org>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>

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(false) && 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);

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(false) &&
-#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(false) &&
-#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(false) &&
-#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 {