exchange_registers(), modified thread_control calls seem to work

- Fixed do_mmap() so that it returns mapped address, and various bugs.
- A child seems to fork with new setup, but with incorrect return value.
  Need to use and test exregs() for fork + clone.
- Shmat searches an unmapped area if input arg is invalid, do_mmap()
  should do this.

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

@@ -59,10 +59,9 @@ typedef int (*__l4_ipc_control_t)(unsigned int action, l4id_t blocked_sender,
 extern __l4_ipc_control_t __l4_ipc_control;
 int l4_ipc_control(unsigned int, l4id_t blocked_sender, u32 blocked_tag);
 
-typedef int (*__l4_exchange_registers_t)(void *exregs_struct,
-					 l4id_t pager, l4id_t tid);
+typedef int (*__l4_exchange_registers_t)(void *exregs_struct, l4id_t tid);
 extern __l4_exchange_registers_t __l4_exchange_registers;
-int l4_exchange_registers(void *exregs_struct, l4id_t pager, l4id_t tid);
+int l4_exchange_registers(void *exregs_struct, l4id_t tid);
 
 typedef int (*__l4_kmem_control_t)(unsigned long pfn, int npages, int grant);
 extern __l4_kmem_control_t __l4_kmem_control;

tasks/libl4/src/arm/syscalls.S

@@ -45,8 +45,11 @@ END_PROC(l4_kread)
  *
  * NOTE: MR_RETURN register is hardcoded here.
  * It must be updated if MR_RETURN offset is changed!
+ *
+ * NOTE: Note that this also breaks l4 system call interface,
+ * this should be moved elsewhere and modified using existing l4 mechanisms.
  */
-BEGIN_PROC(clone_asm)
+BEGIN_PROC(arch_clone)
 	stmfd	sp!, {r4-r8,lr}		@ Save context.
 	utcb_address r12		@ Get utcb address.
 	ldmia	r12!, {r3-r8}		@ Load 6 Message registers from utcb. MR0-MR5
@@ -79,7 +82,7 @@ ipc_failed:
 	utcb_address r12		@ Get utcb
 	stmia	r12, {r3-r8}		@ Store mrs.
 	ldmfd	sp!, {r4-r8,pc}		@ Return restoring pc and context.
-END_PROC(clone_asm)
+END_PROC(arch_clone)
 
 /*
  * Inter-process communication. Loads message registers as arguments before the call,
@@ -186,7 +189,7 @@ END_PROC(l4_space_control)
 
 /*
  * Sets registers of a thread and its pager.
- * @r0 = ptr to exchange_registers structure, @r1 = pager id, @r2 = tid of thread.
+ * @r0 = ptr to exregs_data structure, @r1 = tid of thread.
  */
 BEGIN_PROC(l4_exchange_registers)
 	stmfd	sp!, {lr}

tasks/mm0/include/exregs.h

@@ -6,6 +6,7 @@
 void exregs_set_stack(struct exregs_data *s, unsigned long sp);
 void exregs_set_mr_return(struct exregs_data *s, unsigned long retreg);
 void exregs_set_pc(struct exregs_data *s, unsigned long pc);
+void exregs_set_pager(struct exregs_data *s, l4id_t pagerid);
 
 /*
 exregs_set_stack(unsigned long sp)

tasks/mm0/include/memory.h

@@ -21,7 +21,4 @@ void init_mm_descriptors(struct page_bitmap *page_map,
 			 struct bootdesc *bootdesc, struct membank *membank);
 void init_physmem(struct initdata *initdata, struct membank *membank);
 
-int do_mmap(struct vm_file *mapfile, unsigned long f_offset, struct tcb *t,
-	    unsigned long map_address, unsigned int flags, unsigned int pages);
-
 #endif /* __MEMORY_H__ */

tasks/mm0/include/mmap.h

@@ -26,8 +26,8 @@ struct vm_area *vma_new(unsigned long pfn_start, unsigned long npages,
 
 int do_munmap(void *vaddr, unsigned long size, struct tcb *task);
 
-int do_mmap(struct vm_file *mapfile, unsigned long f_offset, struct tcb *t,
-	    unsigned long map_address, unsigned int flags, unsigned int pages);
+void *do_mmap(struct vm_file *mapfile, unsigned long f_offset, struct tcb *t,
+	      unsigned long map_address, unsigned int flags, unsigned int pages);
 
 int mmap_address_validate(struct tcb *t, unsigned long map_address,
 			  unsigned int vm_flags);

tasks/mm0/src/arch-arm/exregs.c

@@ -7,6 +7,12 @@
 #include <exregs.h>
 
 
+void exregs_set_pager(struct exregs_data *s, l4id_t pagerid)
+{
+	s->pagerid = pagerid;
+	s->flags |= EXREGS_SET_PAGER;
+}
+
 void exregs_set_stack(struct exregs_data *s, unsigned long sp)
 {
 	s->context.sp = sp;

tasks/mm0/src/mmap.c

@@ -380,6 +380,9 @@ int vma_intersect(unsigned long pfn_start, unsigned long pfn_end,
 }
 
 /*
+ * FIXME: PASS THIS A VM_SHARED FLAG SO THAT IT CAN SEARCH FOR AN EMPTY
+ * SEGMENT FOR SHM, instead of shmat() searching for one.
+ *
  * Search an empty space in the task's mmapable address region.
  */
 unsigned long find_unmapped_area(unsigned long npages, struct tcb *task)
@@ -470,9 +473,9 @@ int mmap_address_validate(struct tcb *task, unsigned long map_address,
  * The actual paging in/out of the file from/into memory pages is handled by
  * the file's pager upon page faults.
  */
-int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
-	    struct tcb *task, unsigned long map_address, unsigned int flags,
-	    unsigned int npages)
+void *do_mmap(struct vm_file *mapfile, unsigned long file_offset,
+	      struct tcb *task, unsigned long map_address, unsigned int flags,
+	      unsigned int npages)
 {
 	unsigned long map_pfn = __pfn(map_address);
 	struct vm_area *new, *mapped;
@@ -485,7 +488,7 @@ int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
 			BUG_ON(!(mapfile = get_devzero()));
 			file_offset = 0;
 	       } else
-			BUG();
+		       return PTR_ERR(-EINVAL);
 	}
 
 	/* Get total file pages, check if mapping is within file size */
@@ -494,25 +497,24 @@ int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
 		printf("%s: Trying to map %d pages from page %d, "
 		       "but file length is %d\n", __FUNCTION__,
 		       npages, file_offset, file_npages);
-		return -EINVAL;
+		return PTR_ERR(-EINVAL);
 	}
 
 	/* Check invalid page size */
 	if (npages == 0) {
 		printf("Trying to map %d pages.\n", npages);
-		return -EINVAL;
+		return PTR_ERR(-EINVAL);
 	}
 	if (npages > __pfn(task->stack_start - task->data_end)) {
 		printf("Trying to map too many pages: %d\n", npages);
-		return -ENOMEM;
+		return PTR_ERR(-ENOMEM);
 	}
 
 	/* Check invalid map address */
 	if (!mmap_address_validate(task, map_address, flags)) {
 		/* Get new map address for region of this size */
-		map_address = find_unmapped_area(npages, task);
-		if ((int)map_address < 0)
-			return (int)map_address;
+		if(!(map_address = find_unmapped_area(npages, task)))
+			return PTR_ERR(-ENOMEM);
 	} else {
 		/*
 		 * FIXME: Currently we don't allow overlapping vmas.
@@ -526,12 +528,12 @@ int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
 
 	/* For valid regions that aren't allocated by us, create the vma. */
 	if (!(new = vma_new(__pfn(map_address), npages, flags, file_offset)))
-		return -ENOMEM;
+		return PTR_ERR(-ENOMEM);
 
 	/* Attach the file as the first vm object of this vma */
 	if (!(vmo_link = vm_objlink_create())) {
 		kfree(new);
-		return -ENOMEM;
+		return PTR_ERR(-ENOMEM);
 	}
 
 	/* Attach link to object */
@@ -557,7 +559,7 @@ int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
 		if (!(vmo_link2 = vm_objlink_create())) {
 			kfree(new);
 			kfree(vmo_link);
-			return -ENOMEM;
+			return PTR_ERR(-ENOMEM);
 		}
 		vm_link_object(vmo_link2, &dzero->vm_obj);
 		list_add_tail(&vmo_link2->list, &new->vm_obj_list);
@@ -565,7 +567,7 @@ int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
 
 	/* Finished initialising the vma, add it to task */
 	dprintf("%s: Mapping 0x%x - 0x%x\n", __FUNCTION__,
-		map_address, map_address + npages * PAGE_SIZE);
+		map_address, map_address + __pfn_to_addr(npages));
 	task_add_vma(task, new);
 
 	/*
@@ -573,9 +575,9 @@ int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
 	 * we return the *end* of the area as the start address.
 	 */
 	if (flags & VMA_GROWSDOWN)
-		map_address += npages;
+		map_address += __pfn_to_addr(npages);
 
-	return map_address;
+	return (void *)map_address;
 }
 
 /* mmap system call implementation */
@@ -635,9 +637,9 @@ int sys_mmap(l4id_t sender, void *start, size_t length, int prot,
 	if (prot & PROT_EXEC)
 		vmflags |= VM_EXEC;
 
-	base = do_mmap(file, __pfn_to_addr(pfn), task, base, vmflags, npages);
+	start = do_mmap(file, __pfn_to_addr(pfn), task, base, vmflags, npages);
 
-	l4_ipc_return(base);
+	l4_ipc_return((int)start);
 	return 0;
 }
 

tasks/mm0/src/shm.c

@@ -56,7 +56,7 @@ static void *do_shmat(struct vm_file *shm_file, void *shm_addr, int shmflg,
 {
 	struct shm_descriptor *shm = shm_file_to_desc(shm_file);
 	unsigned int vmflags;
-	int err;
+	void *mapped;
 
 	if (!task) {
 		printf("%s:%s: Cannot find caller task with tid %d\n",
@@ -85,7 +85,7 @@ static void *do_shmat(struct vm_file *shm_file, void *shm_addr, int shmflg,
 		if (mmap_address_validate(task, (unsigned long)shm_addr,
 					  vmflags))
 			shm->shm_addr = shm_addr;
-		else
+		else	/* FIXME: Do this in do_mmap/find_unmapped_area !!! */
 			shm->shm_addr = address_new(&shm_vaddr_pool,
 						    shm->npages);
 	else /* Address must be already assigned */
@@ -95,9 +95,11 @@ static void *do_shmat(struct vm_file *shm_file, void *shm_addr, int shmflg,
 	 * mmap the area to the process as shared. Page fault handler would
 	 * handle allocating and paging-in the shared pages.
 	 */
-	if ((err = do_mmap(shm_file, 0, task, (unsigned long)shm->shm_addr,
-			   vmflags, shm->npages)) < 0) {
-		printf("do_mmap: Mapping shm area failed with %d.\n", err);
+	if (IS_ERR(mapped = do_mmap(shm_file, 0, task,
+				    (unsigned long)shm->shm_addr,
+				    vmflags, shm->npages))) {
+		printf("do_mmap: Mapping shm area failed with %d.\n",
+		       (int)mapped);
 		BUG();
 	}
 

tasks/mm0/src/task.c

@@ -225,36 +225,40 @@ struct tcb *task_create(struct tcb *orig, struct task_ids *ids,
 
 int task_mmap_regions(struct tcb *task, struct vm_file *file)
 {
-	int err;
+	void *mapped;
 	struct vm_file *shm;
 
 	/*
 	 * mmap each task's physical image to task's address space.
 	 * TODO: Map data and text separately when available from bootdesc.
 	 */
-	if ((err = do_mmap(file, 0, task, task->text_start,
-			   VM_READ | VM_WRITE | VM_EXEC | VMA_PRIVATE,
-			   __pfn(page_align_up(task->text_end) -
-			   task->text_start))) < 0) {
-		printf("do_mmap: failed with %d.\n", err);
-		return err;
+	if (IS_ERR(mapped = do_mmap(file, 0, task, task->text_start,
+				    VM_READ | VM_WRITE | VM_EXEC | VMA_PRIVATE,
+				    __pfn(page_align_up(task->text_end) -
+				    task->text_start)))) {
+		printf("do_mmap: failed with %d.\n", (int)mapped);
+		return (int)mapped;
 	}
 
 	/* mmap each task's environment as anonymous memory. */
-	if ((err = do_mmap(0, 0, task, task->env_start,
-			   VM_READ | VM_WRITE | VMA_PRIVATE | VMA_ANONYMOUS,
-			   __pfn(task->env_end - task->env_start))) < 0) {
+	if (IS_ERR(mapped = do_mmap(0, 0, task, task->env_start,
+				    VM_READ | VM_WRITE |
+				    VMA_PRIVATE | VMA_ANONYMOUS,
+				    __pfn(task->env_end - task->env_start)))) {
 		printf("do_mmap: Mapping environment failed with %d.\n",
-		       err);
-		return err;
+		       (int)mapped);
+		return (int)mapped;
 	}
 
 	/* mmap each task's stack as anonymous memory. */
-	if ((err = do_mmap(0, 0, task, task->stack_start,
-			   VM_READ | VM_WRITE | VMA_PRIVATE | VMA_ANONYMOUS,
-			   __pfn(task->stack_end - task->stack_start))) < 0) {
-		printf("do_mmap: Mapping stack failed with %d.\n", err);
-		return err;
+	if (IS_ERR(mapped = do_mmap(0, 0, task, task->stack_start,
+				    VM_READ | VM_WRITE |
+				    VMA_PRIVATE | VMA_ANONYMOUS,
+				    __pfn(task->stack_end -
+					  task->stack_start)))) {
+		printf("do_mmap: Mapping stack failed with %d.\n",
+		       (int)mapped);
+		return (int)mapped;
 	}
 
 	/* Task's utcb */
@@ -304,7 +308,7 @@ int task_setup_registers(struct tcb *task, unsigned int pc,
 			 unsigned int sp, l4id_t pager)
 {
 	int err;
-	struct exregs_data regs;
+	struct exregs_data exregs;
 
 	/* Set up task's registers to default. */
 	if (!sp)
@@ -315,9 +319,11 @@ int task_setup_registers(struct tcb *task, unsigned int pc,
 		pager = self_tid();
 
 	/* Set up the task's thread details, (pc, sp, pager etc.) */
-	exregs_set_stack(&regs, sp);
-	exregs_set_pc(&regs, pc);
-	if ((err = l4_exchange_registers(&regs, pager, task->tid) < 0)) {
+	exregs_set_stack(&exregs, sp);
+	exregs_set_pc(&exregs, pc);
+	exregs_set_pager(&exregs, pager);
+
+	if ((err = l4_exchange_registers(&exregs, task->tid) < 0)) {
 		printf("l4_exchange_registers failed with %d.\n", err);
 		return err;
 	}