Merge pull request #643 from ChinYikMing/fix-syscall-exit

Fix hart halt when non-SDL programs exit via syscall 93

Author: jserv

src/emulate.c

@@ -1444,19 +1444,32 @@ void ecall_handler(riscv_t *rv)
     syscall_handler(rv);
 #elif RV32_HAS(SYSTEM)
     if (rv->priv_mode == RV_PRIV_U_MODE) {
-        switch (rv_get_reg(
-            rv,
-            rv_reg_a7)) { /* trap guestOS's SDL-oriented application syscall */
+        uint32_t reg_a7 = rv_get_reg(rv, rv_reg_a7);
+        switch (reg_a7) { /* trap guestOS's SDL-oriented application syscall */
         case 0xBEEF:
         case 0xC0DE:
         case 0xFEED:
         case 0xBABE:
         case 0xD00D:
-        case 93:
             syscall_handler(rv);
             rv->PC += 4;
             break;
         default:
+#if RV32_HAS(SDL) && RV32_HAS(SYSTEM) && !RV32_HAS(ELF_LOADER)
+            /*
+             * The guestOS may repeatedly open and close the SDL window,
+             * and the user could close the application using the application’s
+             * built-in exit function. Need to trap the built-in exit and
+             * ensure the SDL window and SDL mixer are destroyed properly.
+             */
+            {
+                extern void sdl_video_audio_cleanup();
+                if (unlikely(PRIV(rv)->running_sdl && reg_a7 == 93)) {
+                    sdl_video_audio_cleanup();
+                    PRIV(rv)->running_sdl = false;
+                }
+            }
+#endif
             SET_CAUSE_AND_TVAL_THEN_TRAP(rv, ECALL_U, 0);
             break;
         }

src/riscv.h

@@ -568,6 +568,11 @@ typedef struct {
     bool on_exit;
 #endif
 
+#if RV32_HAS(SDL) && RV32_HAS(SYSTEM) && !RV32_HAS(ELF_LOADER)
+    /* flag to determine if running SDL program in guestOS */
+    bool running_sdl;
+#endif /* SDL */
+
     /* SBI timer */
     uint64_t timer;
 } vm_attr_t;

src/syscall.c

@@ -134,18 +134,6 @@ static void syscall_write(riscv_t *rv)
 
 static void syscall_exit(riscv_t *rv)
 {
-#if RV32_HAS(SDL) && RV32_HAS(SYSTEM) && !RV32_HAS(ELF_LOADER)
-    /*
-     * The guestOS may repeatedly open and close the SDL window,
-     * and the user could close the application using the application’s
-     * built-in exit function. Need to trap the built-in exit and
-     * ensure the SDL window and SDL mixer are destroyed properly.
-     */
-    extern void sdl_video_audio_cleanup();
-    sdl_video_audio_cleanup();
-    return;
-#endif
-
     /* simply halt cpu and save exit code.
      * the application decides the usage of exit code
      */

src/syscall_sdl.c

@@ -393,6 +393,7 @@ void syscall_setup_queue(riscv_t *rv)
      */
     event_queue.base = event_queue.end = 0;
     submission_queue.base = submission_queue.start = 0;
+    PRIV(rv)->running_sdl = true;
 #endif
 
     /* setup_queue(base, capacity, event_count) */