Implement process clone trampoline

libprocess/amd64/.gitignore

@@ -0,0 +1 @@
+*.o

libprocess/amd64/clone_tramp.S

@@ -0,0 +1,7 @@
+.global _clone_tramp
+_clone_tramp:
+  xorq %rbp, %rbp
+  movq %rsp, %rbp
+  andq $-16, %rsp
+
+  callq _clone_tramp1

libprocess/amd64/clone_tramp1.c

@@ -0,0 +1,12 @@
+#include <liballoc.h>
+#include <process.h>
+#include <system.h>
+
+void _clone_tramp1 (void) {
+  struct process_data* pdata = argument_ptr ();
+
+  pdata->fn (pdata->arg_ptr);
+
+  free (pdata);
+  quit ();
+}

libprocess/amd64/src.mk

@@ -0,0 +1,6 @@
+c += amd64/clone_tramp1.c
+
+S += amd64/clone_tramp.S
+
+o += amd64/clone_tramp.o \
+		 amd64/clone_tramp1.o

libprocess/process.c

@@ -7,11 +7,32 @@
 #include <stdint.h>
 #include <system.h>
 
-int process_spawn (process_func_t func, void* argument_ptr) {
+void _clone_tramp (void);
+
+struct process_data* process_spawn (process_func_t func, void* argument_ptr) {
   void* stack = malloc (STACK_SIZE);
   if (stack == NULL)
-    return -ST_OOM_ERROR;
+    return NULL;
+
+  struct process_data* pdata = malloc (sizeof (*pdata));
+
+  if (pdata == NULL) {
+    free (stack);
+    return NULL;
+  }
+
+  pdata->arg_ptr = argument_ptr;
+  pdata->fn = func;
 
   uintptr_t top = (uintptr_t)stack + STACK_SIZE;
-  return clone (top, func, argument_ptr);
+  int pid = clone (top, &_clone_tramp, (void*)pdata);
+
+  if (pid < 0) {
+    free (stack);
+    free (pdata);
+    return NULL;
+  }
+
+  pdata->pid = pid;
+  return pdata;
 }

libprocess/process.h

@@ -8,9 +8,15 @@
 #define STACK_SIZE (256 * PAGE_SIZE)
 
 /* Process entry function */
-typedef void (*process_func_t) (void);
+typedef void (*process_func_t) (void*);
+
+struct process_data {
+  void* arg_ptr;
+  process_func_t fn;
+  int pid;
+};
 
 /* Spawn a new process within the same procgroup with argument */
-int process_spawn (process_func_t func, void* argument_ptr);
+struct process_data* process_spawn (process_func_t func, void* argument_ptr);
 
 #endif // _LIBPROCESS_PROCESS_PROCESS_H

libprocess/src.mk

@@ -1,3 +1,5 @@
+include $(platform)/src.mk
+
 c += process.c
 
 o += process.o