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Added copy-on-write shared memory but untested yet.

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For anonymous shm, mmap now adds a shm_file and devzero behind it
as two vm_objects. Faults are handled by copy_on_write(). Just as
shadows copy r/w pages from original files, it should copy r/w
pages from devzero into the shm_file in front.

shmat/shmget uses mmap to set-up their areas.

Untested yet so bugs expected.

	modified:   tasks/libl4/src/init.c
	modified:   tasks/mm0/include/shm.h
	modified:   tasks/mm0/include/vm_area.h
	modified:   tasks/mm0/src/fault.c
	modified:   tasks/mm0/src/mmap.c
	modified:   tasks/mm0/src/shm.c
This commit is contained in:
Bahadir Balban
2008-03-21 15:40:54 +00:00
parent 466138f125
commit b369ff6efe
6 changed files with 129 additions and 79 deletions
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49
tasks/mm0/src/mmap.c
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@@ -284,9 +284,8 @@ int vma_unmap(struct vm_area **actual, struct vm_area **split,
}
/* Unmaps given address range from its vma. Releases those pages in that vma. */
int do_munmap(void *vaddr, unsigned long size, struct tcb *task)
int do_munmap(void *vaddr, unsigned long npages, struct tcb *task)
{
unsigned long npages = __pfn(size);
unsigned long pfn_start = __pfn(vaddr);
unsigned long pfn_end = pfn_start + npages;
struct vm_area *vma, *vma_new = 0;
@@ -332,7 +331,7 @@ pgtable_unmap:
#endif
int do_munmap(void *vaddr, unsigned long size, struct tcb *task)
int do_munmap(void *vaddr, unsigned long npages, struct tcb *task)
{
return 0;
}
@@ -343,7 +342,7 @@ int sys_munmap(l4id_t sender, void *vaddr, unsigned long size)
BUG_ON(!(task = find_task(sender)));
return do_munmap(vaddr, size, task);
return do_munmap(vaddr, __pfn(page_align_up(size)), task);
}
struct vm_area *vma_new(unsigned long pfn_start, unsigned long npages,
@@ -351,18 +350,11 @@ struct vm_area *vma_new(unsigned long pfn_start, unsigned long npages,
struct vm_file *mapfile)
{
struct vm_area *vma;
struct vm_obj_link *obj_link;
/* Allocate new area */
if (!(vma = kzalloc(sizeof(struct vm_area))))
return 0;
/* Allocate vm object link */
if (!(obj_link = kzalloc(sizeof(struct vm_obj_link)))) {
kfree(vma);
return 0;
}
INIT_LIST_HEAD(&vma->list);
INIT_LIST_HEAD(&vma->vm_obj_list);
@@ -371,11 +363,6 @@ struct vm_area *vma_new(unsigned long pfn_start, unsigned long npages,
vma->flags = flags;
vma->file_offset = file_offset;
INIT_LIST_HEAD(&obj_link->list);
INIT_LIST_HEAD(&obj_link->shref);
obj_link->obj = &mapfile->vm_obj;
list_add(&obj_link->list, &vma->vm_obj_list);
return vma;
}
@@ -469,7 +456,7 @@ int mmap_address_validate(unsigned long map_address, unsigned int vm_flags)
(map_address >= SHM_AREA_START &&
map_address < SHM_AREA_END))
return 1;
else
else
return 0;
} else
BUG();
@@ -487,9 +474,9 @@ int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
unsigned int npages)
{
unsigned long map_pfn = __pfn(map_address);
unsigned long file_npages;
struct vm_area *new, *mapped;
struct vm_obj_link *vmo_link;
struct vm_obj_link *vmo_link, *vmo_link2;
unsigned long file_npages;
/* Set up devzero if none given */
if (!mapfile) {
@@ -550,6 +537,30 @@ int do_mmap(struct vm_file *mapfile, unsigned long file_offset,
mapfile->vm_obj.refcnt++;
list_add_tail(&vmo_link->list, &new->vm_obj_list);
/*
* If the file is a shm file, also map devzero behind it. i.e.
* vma -> vm_link -> vm_link
* | |
* v v
* shm_file devzero
*
* So that faults go through shm file and then devzero, as in
* the shadow object copy_on_write setup in fault.c
*/
if (mapfile->type == VM_FILE_SHM) {
struct vm_file *dzero = get_devzero();
/* Attach the file as the first vm object of this vma */
if (!(vmo_link2 = vm_objlink_create())) {
kfree(new);
kfree(vmo_link);
return -ENOMEM;
}
vmo_link2->obj = &dzero->vm_obj;
dzero->vm_obj.refcnt++;
list_add_tail(&vmo_link2->list, &new->vm_obj_list);
}
/* Finished initialising the vma, add it to task */
printf("%s: Mapping 0x%x - 0x%x\n", __FUNCTION__,
map_address, map_address + npages * PAGE_SIZE);