Fully support userland interrupt handler. Use fixed common abort handler.

Ubiquitous/XiZi_AIoT/services/boards/zynq7000-zc702/usyscall.c

@@ -53,9 +53,9 @@ int exit()
     return syscall(SYSCALL_EXIT, 0, 0, 0, 0);
 }
 
-int yield()
+int yield(task_yield_reason reason)
 {
-    return syscall(SYSCALL_YIELD, 0, 0, 0, 0);
+    return syscall(SYSCALL_YIELD, (uintptr_t)reason, 0, 0, 0);
 }
 
 int kill(int pid)

Ubiquitous/XiZi_AIoT/services/boards/zynq7000-zc702/usyscall.h

@@ -44,6 +44,12 @@ typedef enum {
     SYS_STATE_SHOW_CPU_INFO,
 } sys_state_option;
 
+typedef enum {
+    SYS_TASK_YIELD_NO_REASON = 0x0,
+    SYS_TASK_YIELD_FOREVER = 0x1,
+    SYS_TASK_YIELD_BLOCK_IPC = 0x2,
+} task_yield_reason;
+
 typedef union {
     struct {
         uintptr_t memblock_start;
@@ -58,7 +64,7 @@ typedef int (*ipc_write_fn)(struct Session* session, int fd, char* src, int offs
 
 int spawn(struct Session* session, int fd, ipc_read_fn ipc_read, ipc_fsize_fn ipc_fsize, char* name, char** argv);
 int exit();
-int yield();
+int yield(task_yield_reason reason);
 int kill(int pid);
 int register_server(char* name);
 int session(char* path, int capacity, struct Session* user_session);