target/hppa: Implement halt and reset instructions

Real hardware would use an external device to control the power.
But for the moment let's invent instructions in reserved space,
to be used by our custom firmware.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/hppa/helper.h

@@ -80,6 +80,8 @@ DEF_HELPER_FLAGS_4(fmpynfadd_d, TCG_CALL_NO_RWG, i64, env, i64, i64, i64)
 DEF_HELPER_FLAGS_0(read_interval_timer, TCG_CALL_NO_RWG, tr)
 
 #ifndef CONFIG_USER_ONLY
+DEF_HELPER_1(halt, noreturn, env)
+DEF_HELPER_1(reset, noreturn, env)
 DEF_HELPER_1(rfi, void, env)
 DEF_HELPER_1(rfi_r, void, env)
 DEF_HELPER_FLAGS_2(write_interval_timer, TCG_CALL_NO_RWG, void, env, tr)

target/hppa/op_helper.c

@@ -22,6 +22,7 @@
 #include "exec/exec-all.h"
 #include "exec/helper-proto.h"
 #include "exec/cpu_ldst.h"
+#include "sysemu/sysemu.h"
 #include "qemu/timer.h"
 
 
@@ -639,6 +640,18 @@ void HELPER(write_interval_timer)(CPUHPPAState *env, target_ureg val)
     timer_mod(cpu->alarm_timer, timeout);
 }
 
+void HELPER(halt)(CPUHPPAState *env)
+{
+    qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
+    helper_excp(env, EXCP_HLT);
+}
+
+void HELPER(reset)(CPUHPPAState *env)
+{
+    qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
+    helper_excp(env, EXCP_HLT);
+}
+
 target_ureg HELPER(swap_system_mask)(CPUHPPAState *env, target_ureg nsm)
 {
     target_ulong psw = env->psw;

target/hppa/translate.c

@@ -2302,6 +2302,18 @@ static DisasJumpType trans_rfi(DisasContext *ctx, uint32_t insn,
     /* Exit the TB to recognize new interrupts.  */
     return nullify_end(ctx, DISAS_NORETURN);
 }
+
+static DisasJumpType gen_hlt(DisasContext *ctx, int reset)
+{
+    CHECK_MOST_PRIVILEGED(EXCP_PRIV_OPR);
+    nullify_over(ctx);
+    if (reset) {
+        gen_helper_reset(cpu_env);
+    } else {
+        gen_helper_halt(cpu_env);
+    }
+    return nullify_end(ctx, DISAS_NORETURN);
+}
 #endif /* !CONFIG_USER_ONLY */
 
 static const DisasInsn table_system[] = {
@@ -4519,7 +4531,18 @@ static DisasJumpType translate_one(DisasContext *ctx, uint32_t insn)
     case 0x15: /* unassigned */
     case 0x1D: /* unassigned */
     case 0x37: /* unassigned */
-    case 0x3F: /* unassigned */
+        break;
+    case 0x3F:
+#ifndef CONFIG_USER_ONLY
+        /* Unassigned, but use as system-halt.  */
+        if (insn == 0xfffdead0) {
+            return gen_hlt(ctx, 0); /* halt system */
+        }
+        if (insn == 0xfffdead1) {
+            return gen_hlt(ctx, 1); /* reset system */
+        }
+#endif
+        break;
     default:
         break;
     }