Ongoing work for adding per-thread UTCB structures.

Added setting of utcb address to l4_thread_control.
This is going to be moved to exchange_registers() since we need to pass
both the utcb physical and virtual address and exregs fits such context
modification better than thread_control.

docs/tls.txt

@@ -0,0 +1,50 @@
+	Thread Local Storage and UTCB Access
+
+In an L4-like microkernel such as Codezero, there needs to be a way of
+accessing the User Thread Control Block (UTCB) in order to push argument
+registers and write the IPC payload. This necessitates a convenient method
+of accessing the thread-specific utcb structure. Here are some of the
+possible methods of accessing a thread local storage in general:
+
+1.) Keep a global pointer to it. The scheduler updates the pointer to TLS
+upon every context switch.
+
+2.) Map the private physical TLS page to thread address space at same virtual
+offset, everytime there is a context switch.
+
+3.) Manage everything by the run-time library in the application. This includes
+the following:
+
+ * Predefine a fixed TLS table area on the address space.
+ * Possibly allocate local thread ids E.g. [1..n]
+ * Get current thread id
+ * Take a lock (on the TLS table)
+ * Lookup the pointer to the TLS block by thread id
+ * Release the lock
+ * Return that pointer
+
+The third one is least flexible solution since it requires management of the
+TLS area, has concurrency issues, and limits the number of TLS areas available.
+
+Since UTCB concept is at the heart of Codezero IPC mechanisms, it has to be
+done neatly and flexibly. In that respect lets evaluate solutions:
+
+1.) This is most convenient since user applications can simply reference a
+pointer to get their unique TLS. By this approach no need to spend excessive
+memory by using a page per TLS (in case TLS is less than a page). The downside
+is the UTCB region still needs to be defined by a limit in the address space
+and managed by the pager, if not by the application. This is because every UTCB
+shall be part of an array or a table of unique UTCBs.
+
+2.) Mapping a per-thread physical page to a fixed virtual address upon a context
+switch is the most flexible, since the pager can simply allocate a physical page
+as new threads come to life, and map this when they run, without managing utcb
+table size. The downside is that a page is wasted per-thread.
+
+The solution Codezero uses includes a mixture of both (1) and (2). Upon a
+context switch, a private page is allocated and mapped by the pager, but also
+the UTCB pointer is updated to point at an offset in this page. As an example,
+if a UTCB is sized 1/4th of a page, a single page is used by 4 UTCBs. This way,
+the pager needs to manage 4 entries per-private page, utcbs utilise page memory
+better, and there is no need for a fixed table of utcbs per address space.
+

include/l4/api/exregs.h

@@ -11,9 +11,8 @@
 #include INC_GLUE(context.h)
 #include <l4/types.h>
 
-enum exregs_flags {
-	EXREGS_SET_PAGER = 1,
-};
+#define EXREGS_SET_PAGER		1
+#define	EXREGS_SET_UTCB			2
 
 /* Structure passed by userspace pagers for exchanging registers */
 struct exregs_data {
@@ -21,6 +20,8 @@ struct exregs_data {
 	u32 valid_vect;
 	u32 flags;
 	l4id_t pagerid;
+	unsigned long utcb_phys;
+	unsigned long utcb_virt;
 };
 
 

include/l4/api/kip.h

@@ -68,6 +68,8 @@ struct kip {
 	u32 arch_syscall2;
 	u32 arch_syscall3;
 
+	u32 utcb;
+
 	struct kernel_desc kdesc;
 } __attribute__((__packed__));
 

include/l4/api/thread.h

@@ -1,7 +1,7 @@
 #ifndef __THREAD_H__
 #define __THREAD_H__
 
-#define THREAD_CREATE_MASK		0x00F0
+#define THREAD_CREATE_MASK		0x0030
 
 /* Create new thread and new space */
 #define THREAD_NEW_SPACE		0x0010
@@ -12,7 +12,11 @@
 /* Create new thread, use given space */
 #define THREAD_SAME_SPACE		0x0030
 
-
+/* Shared UTCB, New UTCB, No UTCB */
+#define THREAD_UTCB_MASK		0x00C0
+#define THREAD_UTCB_NEW			0x0040
+#define THREAD_UTCB_SAME		0x0080
+#define THREAD_UTCB_NONE		0x00C0
 
 
 #define THREAD_ACTION_MASK		0x000F

include/l4/generic/tcb.h

@@ -70,7 +70,10 @@ struct ktcb {
 	u32 ts_need_resched;	/* Scheduling flag */
 	enum task_state state;
 	struct list_head task_list; /* Global task list. */
-	struct utcb *utcb;	/* Reference to task's utcb area */
+
+	/* UTCB related, see utcb.txt in docs */
+	unsigned long utcb_virt;	/* Virtual ref to task's utcb area */
+	unsigned long utcb_phys;	/* Physical ref to task's utcb area */
 
 	/* Thread times */
 	u32 kernel_time;	/* Ticks spent in kernel */

include/l4/glue/arm/memlayout.h

@@ -43,7 +43,7 @@
 #define USER_KIP_PAGE		0xFF000000
 
 /* ARM-specific offset in KIP that tells the address of UTCB page */
-#define UTCB_KIP_OFFSET		0xFF0
+#define UTCB_KIP_OFFSET		0x50
 
 #define IO_AREA0_VADDR		(IO_AREA_START + (ARM_SECTION_SIZE*0))
 #define IO_AREA1_VADDR		(IO_AREA_START + (ARM_SECTION_SIZE*1))

include/l4/glue/arm/message.h

@@ -6,6 +6,7 @@
 #ifndef __GLUE_ARM_MESSAGE_H__
 #define __GLUE_ARM_MESSAGE_H__
 
+#define MR_REST			56	
 #define MR_TOTAL		6
 #define MR_TAG			0	/* Contains the purpose of message */
 #define MR_SENDER		1	/* For anythread receivers to discover sender */

libs/c/crt/sys-userspace/arch-arm/crt0.S

@@ -87,7 +87,6 @@
 _start:
 	ldr	sp, =__stack
 	bl	platform_init
-	bl	__l4_init
 	bl	__container_init
 1:
 	b	1b

src/api/syscall.c

@@ -78,6 +78,13 @@ void do_exchange_registers(struct ktcb *task, struct exregs_data *exregs)
 	if (exregs->flags & EXREGS_SET_PAGER)
 		task->pagerid = exregs->pagerid;
 
+	/* Set thread's utcb if supplied */
+	if (exregs->flags & EXREGS_SET_UTCB) {
+		BUG(); /* Check that physical and virtual addresses are in range */
+		task->utcb_phys = exregs->utcb_phys;
+		task->utcb_virt = exregs->utcb_virt;
+	}
+
 }
 
 /*

src/api/thread.c

@@ -164,10 +164,92 @@ int thread_start(struct task_ids *ids)
 	return 0;
 }
 
-int arch_setup_new_thread(struct ktcb *new, struct ktcb *orig, unsigned int flags)
+/*
+ * Given thread creation flags, determines whether to use a new user
+ * (pager)-supplied utcb address, the utcb address of the original thread,
+ * or no utcb at all. Validation of flags done at beginning of thread_create().
+ */
+int arch_new_thread_setup_utcb(struct ktcb *new, struct ktcb *orig, unsigned int flags,
+			       unsigned long utcb_address)
 {
+	unsigned int create_flags = flags & THREAD_CREATE_MASK;
+	unsigned int utcb_flags = flags & THREAD_UTCB_MASK;
+
+	/* In case of multiple threads in same address space */
+	if (create_flags == THREAD_SAME_SPACE) {
+		switch (utcb_flags) {
+		case THREAD_UTCB_SAME:
+			new->utcb_address = orig->utcb_address;
+			break;
+		case THREAD_UTCB_NEW:
+			new->utcb_address = utcb_address;
+			break;
+		case THREAD_UTCB_NONE:
+			new->utcb_address = 0;
+			break;
+		default:
+			printk("%s: Bad thread creation flags. "
+			       "Incorrect flag validation?\n",__FUNCTION__);
+			BUG();
+		}
+	}
+
+	/* In case of brand new address space and thread */
+	if (create_flags == THREAD_NEW_SPACE) {
+		switch (utcb_flags) {
+		case THREAD_UTCB_NEW:
+			new->utcb_address = utcb_address;
+			break;
+			/*
+			 * No UTCB for brand new space means the thread cannot do
+			 * an ipc other than exceptions. This is allowed for now.
+			 */
+		case THREAD_UTCB_NONE:
+			new->utcb_address = 0;
+			break;
+		default:
+			printk("%s: Bad thread creation flags. "
+			       "Incorrect flag validation?\n",__FUNCTION__);
+			BUG();
+		}
+	}
+
+	/*
+	 * This essentially corresponds to fork() and normally we would expect
+	 * the UTCB to be the same as original thread, since the whole address
+	 * space is an identical image of the original. Nevertheless it doesn't
+	 * do harm to have none or different utcb address and this is left to
+	 * the implementor to decide.
+	 */
+	if (create_flags == THREAD_COPY_SPACE) {
+		switch (utcb_flags) {
+		case THREAD_UTCB_SAME:
+			new->utcb_address = orig->utcb_address;
+			break;
+		case THREAD_UTCB_NEW:
+			new->utcb_address = utcb_address;
+			break;
+		case THREAD_UTCB_NONE:
+			new->utcb_address = 0;
+			break;
+		default:
+			printk("%s: Bad thread creation flags. "
+			       "Incorrect flag validation?\n",__FUNCTION__);
+			BUG();
+		}
+	}
+
+	return 0;
+}
+
+int arch_setup_new_thread(struct ktcb *new, struct ktcb *orig,
+			  unsigned int flags, unsigned long utcb_address)
+{
+	/* Set up the utcb address */
+	arch_new_thread_setup_utcb(new, orig, flags, utcb_address);
+
 	/* New threads just need their mode set up */
-	if (flags == THREAD_NEW_SPACE) {
+	if ((flags & THREAD_CREATE_MASK) == THREAD_NEW_SPACE) {
 		BUG_ON(orig);
 		new->context.spsr = ARM_MODE_USR;
 		return 0;
@@ -262,12 +344,28 @@ int thread_setup_new_ids(struct task_ids *ids, unsigned int flags,
  * are respectively used when creating a brand new task, creating a
  * new thread in an existing address space, or forking a task.
  */
-int thread_create(struct task_ids *ids, unsigned int flags)
+int thread_create(struct task_ids *ids, unsigned int flags,
+		  unsigned long utcb_address)
 {
 	struct ktcb *task = 0, *new = (struct ktcb *)zalloc_page();
-	flags &= THREAD_CREATE_MASK;
+	unsigned int create_flags = flags & THREAD_CREATE_MASK;
+	unsigned int utcb_flags = flags & THREAD_UTCB_MASK;
 
-	if (flags == THREAD_NEW_SPACE) {
+	/* Handle error cases. Should have valid flags for each */
+	if (!utcb_flags || !create_flags)
+		return -EINVAL;
+
+	/* Cannot have new space with same utcb */
+	else if (create_flags == THREAD_NEW_SPACE &&
+	    utcb_flags == THREAD_UTCB_SAME)
+		return -EINVAL;
+
+	/* Cannot have new utcb with invalid address */
+	else if (utcb_flags == THREAD_UTCB_NEW && !utcb_address)
+		return -EINVAL;
+
+	/* Determine space allocation */
+	if (create_flags == THREAD_NEW_SPACE) {
 		/* Allocate new pgd and copy all kernel areas */
 		new->pgd = alloc_pgd();
 		copy_pgd_kern_all(new->pgd);
@@ -289,7 +387,7 @@ int thread_create(struct task_ids *ids, unsigned int flags)
 	}
 out:
 	/* Set up new thread's tid, spid, tgid according to flags */
-	thread_setup_new_ids(ids, flags, new, task);
+	thread_setup_new_ids(ids, create_flags, new, task);
 
 	/* Initialise task's scheduling state and parameters. */
 	sched_init_task(new, TASK_PRIO_NORMAL);
@@ -299,7 +397,7 @@ out:
 	waitqueue_head_init(&new->wqh_recv);
 	waitqueue_head_init(&new->wqh_pager);
 
-	arch_setup_new_thread(new, task, flags);
+	arch_setup_new_thread(new, task, flags, utcb_address);
 
 	/* Add task to global hlist of tasks */
 	add_task_global(new);
@@ -317,10 +415,11 @@ int sys_thread_control(syscall_context_t *regs)
 	int ret = 0;
 	unsigned int flags = regs->r0;
 	struct task_ids *ids = (struct task_ids *)regs->r1;
+	unsigned long utcb_address = regs->r2;
 
 	switch (flags & THREAD_ACTION_MASK) {
 	case THREAD_CREATE:
-		ret = thread_create(ids, flags);
+		ret = thread_create(ids, flags, utcb_address);
 		break;
 	case THREAD_RUN:
 		ret = thread_start(ids);

src/generic/scheduler.c

@@ -255,6 +255,9 @@ static inline void context_switch(struct ktcb *next)
 
 	// printk("(%d) to (%d)\n", cur->tid, next->tid);
 
+	/* Update KIP UTCB pointer for new thread to run */
+	kip.utcb = next->utcb_address;
+
 	/* Flush caches and everything */
 	arch_hardware_flush(next->pgd);
 

tasks/fs0/container.c

@@ -0,0 +1,23 @@
+/*
+ * Container entry point for this task
+ *
+ * Copyright (C) 2007-2009 Bahadir Bilgehan Balban
+ */
+#include <posix/posix_init.h>
+#include <l4lib/init.h>
+#include <l4lib/utcb.h>
+
+void main(void);
+
+void __container_init(void)
+{
+	/* Generic L4 thread initialisation */
+	__l4_init();
+
+	/* FS0 posix-service initialisation */
+	posix_service_init();
+
+	/* Entry to main */
+	main();
+}
+

tasks/fs0/include/linker.lds

@@ -32,6 +32,10 @@ SECTIONS
 	.rodata1 : AT (ADDR(.rodata1) - offset) { *(.rodata1) }
 	.data : AT (ADDR(.data) - offset)
 	{
+		. = ALIGN(4K);	/* Align UTCB to page boundary */
+		_start_utcb = .;
+		*(.utcb)
+		_end_utcb = .;
 		. = ALIGN(4K);
 		_start_bdev = .;
 		*(.data.memfs)
@@ -39,5 +43,6 @@ SECTIONS
 		*(.data)
 	}
 	.bss : AT (ADDR(.bss) - offset) { *(.bss) }
+
 	_end = .;
 }

tasks/fs0/src/task.c

@@ -8,6 +8,7 @@
 #include <l4/api/errno.h>
 #include <l4lib/arch/syscalls.h>
 #include <l4lib/arch/syslib.h>
+#include <l4lib/arch/utcb.h>
 #include <l4lib/ipcdefs.h>
 #include <lib/malloc.h>
 #include <lib/idpool.h>
@@ -20,6 +21,7 @@
 #include <syscalls.h>
 #include <globals.h>
 
+
 extern void *shared_page;
 
 struct global_list global_tasks = {

tasks/libl4/include/l4lib/arch-arm/syscalls.h

@@ -6,6 +6,7 @@
 #ifndef __ARM_SYSCALLS_H__
 #define __ARM_SYSCALLS_H__
 
+
 #include <l4lib/arch/types.h>
 #include <l4lib/arch/utcb.h>
 #include <l4/generic/space.h>
@@ -14,6 +15,12 @@
 #include <l4/api/ipc.h>
 #include <l4/api/thread.h>
 
+struct task_ids {
+	int tid;
+	int spid;
+	int tgid;
+};
+
 static inline void *
 l4_kernel_interface(unsigned int *api_version, unsigned int *api_flags,
 		   unsigned int *kernel_id)
@@ -46,9 +53,9 @@ typedef int (*__l4_unmap_t)(void *virt, unsigned long npages, l4id_t tid);
 extern __l4_unmap_t __l4_unmap;
 int l4_unmap(void *virtual, unsigned long numpages, l4id_t tid);
 
-typedef int (*__l4_thread_control_t)(unsigned int action, struct task_ids *ids);
+typedef int (*__l4_thread_control_t)(unsigned int action, struct task_ids *ids, void *utcb_address);
 extern __l4_thread_control_t __l4_thread_control;
-int l4_thread_control(unsigned int action, struct task_ids *ids);
+int l4_thread_control(unsigned int action, struct task_ids *ids, void *utcb_address);
 
 typedef int (*__l4_space_control_t)(unsigned int action, void *kdata);
 extern __l4_space_control_t __l4_space_control;

tasks/libl4/include/l4lib/arch-arm/types.h

@@ -1,13 +1,8 @@
-#ifndef __L4_ARCH_ARM__
-#define __L4_ARCH_ARM__
+#ifndef __L4LIB_ARM_TYPES_H___
+#define __L4LIB_ARM_TYPES_H__
 
 #define TASK_ID_INVALID			-1
-struct task_ids {
-	int tid;
-	int spid;
-	int tgid;
-};
 
 #include <l4/arch/arm/types.h>
 
-#endif
+#endif /* __L4LIB_ARM_TYPES_H__ */

tasks/libl4/include/l4lib/arch-arm/utcb.h

@@ -1,9 +1,12 @@
+/*
+ * Copyright (C) 2009 Bahadir Bilgehan Balban
+ */
 #ifndef __ARM_UTCB_H__
 #define __ARM_UTCB_H__
 
-#define USER_UTCB_REF           0xFF000FF0
+#define USER_UTCB_REF           0xFF000050
 #define L4_KIP_ADDRESS		0xFF000000
-#define UTCB_KIP_OFFSET		0xFF0
+#define UTCB_KIP_OFFSET		0x50
 
 #ifndef __ASSEMBLY__
 #include <l4lib/types.h>
@@ -13,27 +16,37 @@
 #include <string.h>
 #include <stdio.h>
 
+/* UTCB implementation */
+
 /*
  * NOTE: In syslib.h the first few mrs are used by data frequently
  * needed for all ipcs. Those mrs are defined the kernel message.h
  */
 
-/*
- * This is a per-task private structure where message registers are
- * pushed for ipc. Its *not* TLS, but can be part of TLS when it is
- * supported.
- */
 struct utcb {
-	u32 mr[MR_TOTAL];
-	u32 saved_tag;
-	u32 saved_sender;
-} __attribute__((__packed__));
+	u32 mr[MR_TOTAL];	/* MRs that are mapped to real registers */
+	u32 saved_tag;		/* Saved tag field for stacked ipcs */
+	u32 saved_sender;	/* Saved sender field for stacked ipcs */
+	u32 mr_rest[MR_REST];	/* Complete the utcb for up to 64 words */
+};
 
-extern struct utcb utcb;
+extern struct kip *kip;
+
+
+/*
+ * Pointer to Kernel Interface Page's UTCB pointer offset.
+ */
+extern struct utcb **kip_utcb_ref;
 
 static inline struct utcb *l4_get_utcb()
 {
-	return &utcb;
+ 	/*
+	 * By double dereferencing, we get the private TLS (aka UTCB). First
+	 * reference is to the KIP's utcb offset, second is to the utcb itself,
+	 * to which the KIP's utcb reference had been updated during context
+	 * switch.
+	 */
+	return *kip_utcb_ref;
 }
 
 /* Functions to read/write utcb registers */

tasks/libl4/include/l4lib/exregs.h

@@ -7,6 +7,7 @@ void exregs_set_stack(struct exregs_data *s, unsigned long sp);
 void exregs_set_mr(struct exregs_data *s, int offset, unsigned long val);
 void exregs_set_pc(struct exregs_data *s, unsigned long pc);
 void exregs_set_pager(struct exregs_data *s, l4id_t pagerid);
+void exregs_set_utcb(struct exregs_data *s, unsigned long phys, unsigned long virt);
 
 /*
 exregs_set_stack(unsigned long sp)

tasks/libl4/include/l4lib/init.h

@@ -0,0 +1,6 @@
+#ifndef __L4LIB_INIT__
+#define __L4LIB_INIT__
+
+void __l4_init(void);
+
+#endif

tasks/libl4/include/l4lib/thread.h

@@ -0,0 +1,14 @@
+#ifndef __L4_THREAD_H__
+#define __L4_THREAD_H__
+
+#include <libl4/arch/utcb.h>
+#include <libl4/arch/types.h>
+
+struct l4_thread_struct {
+	l4id_t tlid;			/* Thread local id */
+	struct task_ids ids;		/* Thread L4-defined ids */
+	struct utcb *utcb;		/* Thread utcb */
+	unsigned long stack_start;	/* Thread start of stack */
+};
+
+#endif /* __L4_THREAD_H__ */

tasks/libl4/src/arm/exregs.c

@@ -9,6 +9,7 @@
 #include INC_GLUE(message.h)
 
 
+
 void exregs_set_mr(struct exregs_data *s, int offset, unsigned long val)
 {
 	/* Get MR0 */
@@ -30,6 +31,14 @@ void exregs_set_pager(struct exregs_data *s, l4id_t pagerid)
 	s->flags |= EXREGS_SET_PAGER;
 }
 
+void exregs_set_utcb(struct exregs_data *s, unsigned long phys,
+		     unsigned long virt)
+{
+	s->utcb_phys = phys;
+	s->utcb_virt = virt;
+	s->flags |= EXREGS_SET_UTCB;
+}
+
 void exregs_set_stack(struct exregs_data *s, unsigned long sp)
 {
 	s->context.sp = sp;

tasks/libl4/src/arm/syscalls.S

@@ -9,9 +9,18 @@
 #include <l4/macros.h>
 #include INC_GLUE(message.h)
 
+/* Old macro */
+#if 0
 	.macro	utcb_address	rx
 		ldr	\rx, =utcb
 	.endm
+#endif
+
+	/* New macro does double dereference */
+	.macro	utcb_address	rx
+		ldr	\rx, =kip_utcb_ref	@ First get pointer to utcb pointer in KIP
+		ldr	\rx, [\rx]		@ Get UTCB address from UTCB pointer in KIP
+	.endm
 
 BEGIN_PROC(l4_thread_switch)
 	ldr	r12, =__l4_thread_switch
@@ -152,7 +161,7 @@ END_PROC(l4_time)
 
 /*
  * System call that controls thread creation, destruction and modification.
- * @r0 = thread action, @r1 = &ids
+ * @r0 = thread action, @r1 = &ids, @r2 = utcb address
  */
 BEGIN_PROC(l4_thread_control)
 	stmfd	sp!, {lr}

tasks/libl4/src/init.c

@@ -1,7 +1,7 @@
 /*
- * Initialise system call offsets.
+ * Initialise system call offsets and utcb reference.
  *
- * Copyright (C) 2007, 2008 Bahadir Balban
+ * Copyright (C) 2007-2009 Bahadir Bilgehan Balban
  */
 #include <l4lib/kip.h>
 #include <l4lib/arch/syslib.h>
@@ -27,16 +27,20 @@ __l4_time_t __l4_time = 0;
 struct kip *kip;
 
 /*
- * Private UTCB of this task. Used only for pushing/reading ipc
- * message registers.
+ * Reference to private UTCB of this thread.
+ * Used only for pushing/reading ipc message registers.
  */
-struct utcb utcb;
+struct utcb **kip_utcb_ref;
 
 
 void __l4_init(void)
 {
+	/* Kernel interface page */
 	kip = l4_kernel_interface(0, 0, 0);
 
+	/* Reference to utcb field of KIP */
+	kip_utcb_ref = (struct utcb **)&kip->utcb;
+
 	__l4_ipc =		(__l4_ipc_t)kip->ipc;
 	__l4_map =		(__l4_map_t)kip->map;
 	__l4_unmap =		(__l4_unmap_t)kip->unmap;

tasks/libposix/fork.c

@@ -12,7 +12,7 @@
 #include <l4lib/utcb.h>
 #include <l4/macros.h>
 #include INC_GLUE(memory.h)
-#include <posix_init.h>
+#include <shpage.h>
 
 static inline int l4_fork(void)
 {
@@ -43,10 +43,10 @@ int fork(void)
 
 	/*
 	 * If we're a child, we need to initialise the default
-	 * shared page via posix_init()
+	 * shared page via libposix_init()
 	 */
 	if (ret == 0)
-		posix_init();
+		shared_page_init();
 
 	return ret;
 }

tasks/libposix/include/posix/posix_init.h

@@ -1,6 +1,7 @@
-#ifndef __POSIX_INIT_H__
-#define __POSIX_INIT_H__
+#ifndef __LIBPOSIX_INIT_H__
+#define __LIBPOSIX_INIT_H__
 
-void posix_init(void);
+void libposix_init(void);
+void posix_service_init(void);
 
-#endif /* __POSIX_INIT_H__ */
+#endif /* __LIBPOSIX_INIT_H__ */

tasks/libposix/init.c

@@ -3,28 +3,20 @@
  *
  * Copyright (C) 2007-2009 Bahadir Balban
  */
-
 #include <shpage.h>
 #include <posix_init.h>
 
-void posix_init(void)
+void posix_service_init(void)
 {
 	/* Non-pager tasks initialise their shared communication page */
-	if (self_tid() != PAGER_TID)
-		shared_page_init();
+	BUG_ON(self_tid() != VFS_TID);
+	shared_page_init();
 }
 
-int main(void);
-
-/*
- * Entry point for posix services container.
- *
- * This is executed by all posix system services and tasks
- * that run in this container.
- */
-void __container_init(void)
+void libposix_init(void)
 {
-	posix_init();
-	main();
+	/* Shall only be run by posix applications */
+	BUG_ON(self_tid() == PAGER_TID || self_tid() == VFS_TID);
+	shared_page_init();
 }
 

tasks/mm0/container.c

@@ -0,0 +1,28 @@
+/*
+ * Container entry point for pager
+ *
+ * Copyright (C) 2007-2009 Bahadir Bilgehan Balban
+ */
+
+#include <posix/posix_init.h>
+#include <l4lib/init.h>
+#include <l4lib/utcb.h>
+
+/*
+ * Application specific utcb allocation
+ * for this container.
+ *
+ * Copyright (C) 2007-2009 Bahadir Balban
+ */
+
+void main(void);
+
+void __container_init(void)
+{
+	/* Generic L4 initialisation */
+	__l4_init();
+
+	/* Entry to main */
+	main();
+}
+

tasks/mm0/include/linker.lds

@@ -29,7 +29,11 @@ SECTIONS
 	/* rodata is needed else your strings will link at physical! */
 	.rodata : AT (ADDR(.rodata) - offset) { *(.rodata) }
 	.rodata1 : AT (ADDR(.rodata1) - offset) { *(.rodata1) }
-	.data : AT (ADDR(.data) - offset) { *(.data) }
+	.data : AT (ADDR(.data) - offset)
+	{
+		*(.data)
+	}
+	. = ALIGN(4K);
 	_start_init = .;
 	.init : AT (ADDR(.init) - offset) { *(.init.stack) }
 	. = ALIGN(8);

tasks/mm0/include/task.h

@@ -11,6 +11,7 @@
 #include INC_GLUE(memlayout.h)
 #include <l4/lib/list.h>
 #include <l4lib/arch/types.h>
+#include <l4lib/arch/syscalls.h>
 #include <l4lib/utcb.h>
 #include <lib/addr.h>
 #include <l4/api/kip.h>
@@ -53,6 +54,20 @@ struct task_vma_head {
 	int tcb_refs;
 };
 
+/*
+ * TLS and UTCB bookkeeping:
+ *
+ * This structure is shared among threads whose utcbs are on the same
+ * physical page. Threads with utcbs on different physical pages have
+ * their own utcb_data structure, even though they are in the same
+ * address space, and share their vm_area_list structure.
+ */
+struct utcb_data {
+	unsigned long phys;	/* Physical utcb address */
+	unsigned long virt;	/* Virtual utcb address */
+	u32 bit;		/* Bitvector of free utcb slots on page */
+	struct page *p;		/* Physical page */
+};
 
 /* Stores all task information that can be kept in userspace. */
 struct tcb {
@@ -104,6 +119,9 @@ struct tcb {
 	/* Default ipc-shared-page information */
 	void *shared_page;
 
+	/* Task's utcb data */
+	struct utcb_data *utcb;
+
 	/* Virtual memory areas */
 	struct task_vma_head *vm_area_head;
 

tasks/mm0/include/vm_area.h

@@ -7,10 +7,10 @@
 #define __VM_AREA_H__
 
 #include <stdio.h>
-#include <task.h>
 #include <l4/macros.h>
 #include <l4/config.h>
 #include <l4/types.h>
+#include <task.h>
 #include <arch/mm.h>
 #include <lib/spinlock.h>
 

tasks/mm0/src/init.c

@@ -18,6 +18,7 @@
 #include <test.h>
 #include <boot.h>
 
+
 /* A separate list than the generic file list that keeps just the boot files */
 LIST_HEAD(boot_file_list);
 

tasks/mm0/src/utcb.c

@@ -0,0 +1,27 @@
+/*
+ * Management of task utcb regions and own utcb.
+ *
+ * Copyright (C) 2007-2009 Bahadir Bilgehan Balban
+ */
+
+#include <l4lib/arch/utcb.h>
+#include <l4/macros.h>
+
+/*
+ * UTCB management in Codezero:
+ *
+ * 1.) Every task in the system defines an array of utcbs in a special .utcb
+ *     section that is page-aligned and to be kept wired in by the pager.
+ * 2.) The region marks are written to bootdesc structure at compile-time.
+ * 3.) Pager reads the bootdesc struct from the microkernel during init.
+ * 4.) Pager initialises structures to alloc/dealloc new utcbs for every address
+ *     space.
+ * 5.) Pagers dynamically allocate utcb addresses as each thread is created
+ *     via a thread_control() system call.
+ * 6.) Each thread in an address space learns their utcb address from a
+ *     well-defined KIP offset. This is updated as each thread becomes runnable.
+ */
+
+
+
+

tasks/test0/SConstruct

@@ -68,7 +68,7 @@ env = Environment(CC = 'arm-none-linux-gnueabi-gcc',
 		  CPPFLAGS = "-D__USERSPACE__",
 		  CPPPATH = ['#include', libl4_incpath, libposix_incpath, kernel_incpath])
 
-src = [glob("src/*.c"), glob("*.c"), glob("*.S"), glob("src/arch/arm/*.c")]
+src = [glob("src/*.c"), glob("*.c"), glob("*.S"), glob("src/arch/arm/*.c"), glob("../libcont/*.c")]
 objs = env.Object(src)
 physical_base = env.Command(physical_base_ld_script, prev_image, get_physical_base)
 crt0_copied = env.Command("crt0.o", libc_crt0, copy_crt0)

tasks/test0/container.c

@@ -0,0 +1,25 @@
+/*
+ * Container entry point for this task.
+ *
+ * Copyright (C) 2007-2009 Bahadir Bilgehan Balban
+ */
+
+#include <l4lib/types.h>
+#include <l4lib/init.h>
+#include <l4lib/utcb.h>
+#include <posix_init.h>		/* Initialisers for posix library */
+
+void main(void);
+
+void __container_init(void)
+{
+	/* Generic L4 thread initialisation */
+	__l4_init();
+
+	/* Initialise posix library for application */
+	libposix_init();
+
+	/* Entry to main */
+	main();
+}
+

tasks/test0/include/linker.lds

@@ -30,10 +30,9 @@ SECTIONS
 	/* rodata is needed else your strings will link at physical! */
 	.rodata : AT (ADDR(.rodata) - offset) { *(.rodata) }
 	.rodata1 : AT (ADDR(.rodata1) - offset) { *(.rodata1) }
-
-	. = ALIGN(4K);
 	.data : AT (ADDR(.data) - offset)
 	{
+		. = ALIGN(4K);
 		_start_test1 = .;
 		*(.test1)
 		_end_test1 = .;