Add a threading syscall API.

zion/usr/zcall.cpp

@@ -2,12 +2,27 @@
 
 #include <stdint.h>
 
+uint64_t SysCall0(uint64_t number) {
+  uint64_t return_code;
+  asm("syscall" : "=a"(return_code) : "D"(number));
+  return return_code;
+}
+
 uint64_t SysCall1(uint64_t number, const void* first) {
   uint64_t return_code;
   asm("syscall" : "=a"(return_code) : "D"(number), "S"(first) : "rcx", "r11");
   return return_code;
 }
 
+uint64_t SysCall2(uint64_t number, const void* first, const void* second) {
+  uint64_t return_code;
+  asm("syscall"
+      : "=a"(return_code)
+      : "D"(number), "S"(first), "d"(second)
+      : "rcx", "r11");
+  return return_code;
+}
+
 uint64_t ZDebug(const char* message) {
   return SysCall1(Z_DEBUG_PRINT, message);
 }
@@ -21,3 +36,26 @@ uint64_t ZProcessSpawnElf(uint64_t cap_id, uint64_t elf_base,
   };
   return SysCall1(Z_PROCESS_SPAWN, &req);
 }
+
+uint64_t ZThreadCreate(uint64_t proc_cap, uint64_t* thread_cap) {
+  ZThreadCreateReq req{
+      .proc_cap = proc_cap,
+  };
+  ZThreadCreateResp resp;
+  uint64_t ret = SysCall2(Z_THREAD_CREATE, &req, &resp);
+  *thread_cap = resp.thread_cap;
+  return ret;
+}
+
+uint64_t ZThreadStart(uint64_t thread_cap, uint64_t entry, uint64_t arg1,
+                      uint64_t arg2) {
+  ZThreadStartReq req{
+      .thread_cap = thread_cap,
+      .entry = entry,
+      .arg1 = arg1,
+      .arg2 = arg2,
+  };
+  return SysCall1(Z_THREAD_START, &req);
+}
+
+void ZThreadExit() { SysCall0(Z_THREAD_EXIT); }