Modified task initialisation so that stack now comes beneath the environment

Environment is backed by a special per-task file maintained by mm0 for each task.
This file is filled in by the env pager, by simple copying of env data into the
faulty page upon a fault. UTCB and all anon regions (stack) could use the same
scheme.

Fixed IS_ERR(x) to accept negative values that are above -1000 for errors. This
protects against false positives for pointers such as 0xE0000000.

	modified:   include/l4/generic/scheduler.h
	modified:   include/l4/macros.h
	modified:   src/arch/arm/exception.c
	modified:   tasks/fs0/include/linker.lds
	modified:   tasks/libl4/src/init.c
	modified:   tasks/libposix/shm.c
	new file:   tasks/mm0/include/env.h
	modified:   tasks/mm0/include/file.h
	new file:   tasks/mm0/include/lib/addr.h
	deleted:    tasks/mm0/include/lib/vaddr.h
	modified:   tasks/mm0/include/task.h
	new file:   tasks/mm0/include/utcb.h
	new file:   tasks/mm0/src/env.c
	modified:   tasks/mm0/src/fault.c
	modified:   tasks/mm0/src/file.c
	modified:   tasks/mm0/src/init.c
	new file:   tasks/mm0/src/lib/addr.c
	modified:   tasks/mm0/src/lib/idpool.c
	deleted:    tasks/mm0/src/lib/vaddr.c
	modified:   tasks/mm0/src/mmap.c
	modified:   tasks/mm0/src/shm.c
	modified:   tasks/mm0/src/task.c
	new file:   tasks/mm0/src/utcb.c
	modified:   tasks/test0/include/linker.lds

tasks/mm0/include/env.h

@@ -0,0 +1,6 @@
+#ifndef __MM0_ENV__
+#define __MM0_ENV__
+
+int task_prepare_env_file(struct tcb *t);
+
+#endif

tasks/mm0/include/file.h

@@ -5,6 +5,7 @@
 #include <posix/sys/types.h>
 
 void vmfile_init(void);
+
 struct vm_file *vmfile_alloc_init(void);
 int vfs_receive_sys_open(l4id_t sender, l4id_t opener, int fd,
 			 unsigned long vnum, unsigned long size);
@@ -16,4 +17,5 @@ int sys_read(l4id_t sender, int fd, void *buf, int count);
 int sys_write(l4id_t sender, int fd, void *buf, int count);
 int sys_lseek(l4id_t sender, int fd, off_t offset, int whence);
 
+extern struct list_head vm_file_list;
 #endif /* __MM0_FILE_H__ */

tasks/mm0/include/lib/addr.h

@@ -0,0 +1,23 @@
+/*
+ * Address allocation pool
+ *
+ * Copyright (C) 2007 Bahadir Balban
+ */
+#ifndef __ADDR_H__
+#define __ADDR_H__
+
+#include <lib/idpool.h>
+
+/* Address pool to allocate from a range of addresses */
+struct address_pool {
+	struct id_pool *idpool;
+	unsigned long start;
+	unsigned long end;
+};
+
+int address_pool_init(struct address_pool *pool, unsigned long start,
+		      unsigned long end);
+void *address_new(struct address_pool *pool, int npages);
+int address_del(struct address_pool *, void *addr, int npages);
+
+#endif /* __ADDR_H__ */

tasks/mm0/include/lib/vaddr.h

@@ -1,17 +0,0 @@
-/*
- * Virtual address allocation pool (for shm)
- *
- * Copyright (C) 2007 Bahadir Balban
- */
-#ifndef __VADDR_H__
-#define __VADDR_H__
-
-#include <lib/idpool.h>
-
-void vaddr_pool_init(struct id_pool *pool, unsigned long start,
-		     unsigned long end);
-void *vaddr_new(struct id_pool *pool, int npages);
-int vaddr_del(struct id_pool *, void *vaddr, int npages);
-
-#endif /* __VADDR_H__ */
-

tasks/mm0/include/task.h

@@ -12,6 +12,7 @@
 #include <l4/lib/list.h>
 #include <l4lib/types.h>
 #include <l4lib/utcb.h>
+#include <lib/addr.h>
 
 #define __TASKNAME__		__PAGERNAME__
 
@@ -43,7 +44,7 @@ struct tcb {
 	/* Related task ids */
 	unsigned int pagerid;	/* Task's pager */
 
-	/* Program segment marks */
+	/* Program segment marks, ends exclusive as usual */
 	unsigned long text_start;
 	unsigned long text_end;
 	unsigned long data_start;
@@ -51,9 +52,9 @@ struct tcb {
 	unsigned long bss_start;
 	unsigned long bss_end;
 	unsigned long stack_start;
-	unsigned long stack_end;   /* Exclusive of last currently mapped page */
+	unsigned long stack_end;
 	unsigned long heap_start;
-	unsigned long heap_end;    /* Exclusive of last currently mapped page */
+	unsigned long heap_end;
 	unsigned long env_start;
 	unsigned long env_end;
 	unsigned long args_start;
@@ -62,17 +63,24 @@ struct tcb {
 	/* UTCB address */
 	unsigned long utcb_address;
 
+	/* Temporary storage for environment data */
+	void *env_data;
+	unsigned long env_size;
+
+	/* Per-task environment file */
+	struct vm_file *env_file;
+
 	/* Virtual memory areas */
 	struct list_head vm_area_list;
 
-	/* Per-task swap file for now */
-	struct vm_file *swap_file;
-
 	/* File descriptors for this task */
 	struct file_descriptor fd[TASK_OFILES_MAX];
 
+	/* Per-task swap file for now */
+	struct vm_file *swap_file;
+
 	/* Pool to generate swap file offsets for fileless anonymous regions */
-	struct id_pool *swap_file_offset_pool;
+	struct address_pool swap_file_offset_pool;
 };
 
 struct tcb *find_task(int tid);

tasks/mm0/include/utcb.h

@@ -0,0 +1,7 @@
+#ifndef __MM0_UTCB_H__
+#define __MM0_UTCB_H__
+
+void *utcb_vaddr_new(void);
+int utcb_pool_init(void);
+
+#endif