[PATCH 08/14] add thread creation helper to tests

[Luca Dariz]

---
 tests/include/testlib.h |  1 +
 tests/testlib.c         | 53 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/tests/include/testlib.h b/tests/include/testlib.h
index 2b7a67c0..52605047 100644
--- a/tests/include/testlib.h
+++ b/tests/include/testlib.h
@@ -48,6 +48,7 @@ const char* e2s(int err);
 const char* e2s_gnumach(int err);
 void halt();
 int msleep(uint32_t timeout);
+thread_t test_thread_start(task_t task, void(*routine)(void*), void* arg);
 
 mach_port_t host_priv(void);
 mach_port_t device_priv(void);
diff --git a/tests/testlib.c b/tests/testlib.c
index 6abe8c4d..e6be46ee 100644
--- a/tests/testlib.c
+++ b/tests/testlib.c
@@ -95,3 +95,56 @@ void _start()
   printf("%s: test %s exit code %x\n", TEST_SUCCESS_MARKER, argv[0], ret);
   halt();
 }
+
+// started from 
https://github.com/dwarfmaster/mach-ipc/blob/master/minimal_threads/main.c
+
+static uint32_t stack_top[PAGE_SIZE]  __attribute__ ((aligned (PAGE_SIZE)));
+thread_t test_thread_start(task_t task, void(*routine)(void*), void* arg) {
+  const vm_size_t stack_size = PAGE_SIZE * 16;
+  kern_return_t ret;
+  vm_address_t stack;
+
+  ret = vm_allocate(task, &stack, stack_size, TRUE);
+  ASSERT_RET(ret, "can't allocate the stack for a new thread");
+
+  ret = vm_protect(task, stack, PAGE_SIZE, FALSE, VM_PROT_NONE);
+  ASSERT_RET(ret, "can't protect the stack from overflows");
+
+  long *top = (long*)((vm_offset_t)stack_top + PAGE_SIZE) - 2;
+  *top = 0;        /* The return address */
+#ifndef __x86_64__
+  *(top + 1) = (long)arg; /* The argument is passed on the stack on x86_32 */
+#endif
+  ret = vm_write(task, stack + stack_size - PAGE_SIZE, (vm_offset_t)stack_top, 
PAGE_SIZE);
+  ASSERT_RET(ret, "can't initialize the stack for the new thread");
+
+  thread_t thread;
+  ret = thread_create(task, &thread);
+  ASSERT_RET(ret, "thread_create()");
+
+  struct i386_thread_state state;
+  unsigned int count;
+  count = i386_THREAD_STATE_COUNT;
+  ret = thread_get_state(thread, i386_REGS_SEGS_STATE,
+                         (thread_state_t) &state, &count);
+  ASSERT_RET(ret, "thread_get_state()");
+
+#ifdef __x86_64__
+  state.rip = (long) routine;
+  state.ursp = (long) (stack + stack_size - 16);
+  state.rbp = 0;
+  state.rdi = (long)arg;
+#else
+  state.eip = (long) routine;
+  state.uesp = (long) (stack + stack_size - 8);
+  state.ebp = 0;
+#endif
+  ret = thread_set_state(thread, i386_REGS_SEGS_STATE,
+                         (thread_state_t) &state, i386_THREAD_STATE_COUNT);
+  ASSERT_RET(ret, "thread_set_state");
+
+  ret = thread_resume(thread);
+  ASSERT_RET(ret, "thread_resume");
+
+  return thread;
+}
-- 
2.39.2