diff options
Diffstat (limited to 'src/kernel/user/pager.c')
| -rw-r--r-- | src/kernel/user/pager.c | 185 |
1 files changed, 163 insertions, 22 deletions
diff --git a/src/kernel/user/pager.c b/src/kernel/user/pager.c index c892599..f03e45b 100644 --- a/src/kernel/user/pager.c +++ b/src/kernel/user/pager.c @@ -15,12 +15,14 @@ static void swap_page_in(pager_t *p, size_t offset, size_t len); static void swap_page_out(pager_t *p, size_t offset, size_t len); static void swap_page_release(pager_t *p, size_t offset, size_t len); +static bool swap_resize(pager_t *p, size_t new_size); static pager_ops_t swap_pager_ops = { .page_in = swap_page_in, .page_commit = 0, .page_out = swap_page_out, .page_release = swap_page_release, + .resize = swap_resize, }; pager_t *new_swap_pager(size_t size) { @@ -44,17 +46,15 @@ error: void swap_page_in(pager_t *p, size_t offset, size_t len) { ASSERT(PAGE_ALIGNED(offset)); - size_t npages = PAGE_ALIGN_UP(len) / PAGE_SIZE; - void *region = region_alloc(PAGE_SIZE, "Page zero area", 0); + void *region = region_alloc(PAGE_SIZE, "Page zeroing area", 0); if (region == 0) return; - for (size_t i = 0; i < npages; i++) { - size_t page = offset + (i * PAGE_SIZE); + for (size_t page = offset; page < offset + len; page += PAGE_SIZE) { if (hashtbl_find(p->pages, (void*)page) == 0) { uint32_t frame = frame_alloc(1); if (frame != 0) { - pd_map_page(region, frame, true); + if (!pd_map_page(region, frame, true)) PANIC("TODO");; memset(region, 0, PAGE_SIZE); pd_unmap_page(region); } @@ -73,10 +73,8 @@ void swap_page_out(pager_t *p, size_t offset, size_t len) { void swap_page_release(pager_t *p, size_t offset, size_t len) { ASSERT(PAGE_ALIGNED(offset)); - size_t npages = PAGE_ALIGN_UP(len) / PAGE_SIZE; - for (size_t i = 0; i < npages; i++) { - size_t page = offset + (i * PAGE_SIZE); + for (size_t page = offset; page < offset + len; page += PAGE_SIZE) { uint32_t frame = (uint32_t)hashtbl_find(p->pages, (void*)page) >> ENT_FRAME_SHIFT; if (frame != 0) { hashtbl_remove(p->pages, (void*)page); @@ -85,6 +83,79 @@ void swap_page_release(pager_t *p, size_t offset, size_t len) { } } +bool swap_resize(pager_t *p, size_t new_size) { + // later : remove unused pages in swap file + + swap_page_release(p, PAGE_ALIGN_UP(new_size), p->size - PAGE_ALIGN_UP(new_size)); + + size_t last_page = PAGE_ALIGN_DOWN(new_size); + + if (!PAGE_ALIGNED(new_size) && hashtbl_find(p->pages, (void*)last_page) != 0) { + void *region = region_alloc(PAGE_SIZE, "Page zeroing area", 0); + if (!region) PANIC("TODO"); + + uint32_t frame = (uint32_t)hashtbl_find(p->pages, (void*)last_page) >> ENT_FRAME_SHIFT; + ASSERT(frame != 0); + + if (!pd_map_page(region, frame, true)) PANIC("TODO"); + + size_t b0 = new_size - last_page; + memset(region + b0, 0, PAGE_SIZE - b0); + + pd_unmap_page(region); + + region_free(region); + } + + return true; +} + +// ============ // +// DEVICE PAGER // +// ============ // + +static void device_page_in(pager_t *p, size_t offset, size_t len); + +static pager_ops_t device_pager_ops = { + .page_in = device_page_in, + .page_commit = 0, + .page_out = 0, + .page_release = 0, + .resize = 0, +}; + +pager_t *new_device_page(size_t size, size_t phys_offset) { + ASSERT(PAGE_ALIGNED(phys_offset)); + + pager_t *p = (pager_t*)malloc(sizeof(pager_t)); + if (p == 0) return 0; + + p->pages = create_hashtbl(id_key_eq_fun, id_hash_fun, 0); + if (p->pages == 0) goto error; + + p->ops = &device_pager_ops; + p->size = size; + p->lock = MUTEX_UNLOCKED; + p->maps = 0; + p->device_pager.phys_offset = phys_offset; + + return p; + +error: + if (p) free(p); + return 0; +} + +void device_page_in(pager_t *p, size_t offset, size_t len) { + ASSERT(PAGE_ALIGNED(offset)); + + for (size_t page = offset; page < offset + len; page += PAGE_SIZE) { + if (hashtbl_find(p->pages, (void*)page) == 0) { + hashtbl_add(p->pages, (void*)page, (void*)(p->device_pager.phys_offset + page)); + } + } +} + // ======================= // // GENERIC PAGER FUNCTIONS // // ======================= // @@ -92,23 +163,33 @@ void swap_page_release(pager_t *p, size_t offset, size_t len) { void delete_pager(pager_t *p) { ASSERT(p->maps == 0); - pager_commit_dirty(p); - mutex_lock(&p->lock); - p->ops->page_release(p, 0, p->size); + if (p->ops->page_commit) p->ops->page_commit(p, 0, p->size); + if (p->ops->page_release) p->ops->page_release(p, 0, p->size); + delete_hashtbl(p->pages); free(p); } +bool pager_resize(pager_t *p, size_t newsize) { + if (!p->ops->resize) return false; + + mutex_lock(&p->lock); + + bool ret = p->ops->resize(p, newsize); + + mutex_unlock(&p->lock); + + return ret; +} + void pager_access(pager_t *p, size_t offset, size_t len, bool accessed, bool dirty) { mutex_lock(&p->lock); ASSERT(PAGE_ALIGNED(offset)); - size_t npages = PAGE_ALIGN_UP(len) / PAGE_SIZE; - for (size_t i = 0; i < npages; i++) { - size_t page = offset + (i * PAGE_SIZE); + for (size_t page = offset; page < offset + len; page += PAGE_SIZE) { uint32_t v = (uint32_t)hashtbl_find(p->pages, (void*)page); if (v != 0) { hashtbl_change(p->pages, (void*)page, @@ -124,14 +205,7 @@ void pager_commit_dirty(pager_t *p) { mutex_lock(&p->lock); - for (size_t i = 0; i < p->size; i += PAGE_SIZE) { - uint32_t v = (uint32_t)hashtbl_find(p->pages, (void*)i); - if (v & PAGE_DIRTY) { - p->ops->page_commit(p, i, PAGE_SIZE); - hashtbl_change(p->pages, (void*)i, (void*)(v & ~PAGE_DIRTY)); - } - - } + p->ops->page_commit(p, 0, p->size); mutex_unlock(&p->lock); } @@ -153,6 +227,59 @@ int pager_get_frame(pager_t *p, size_t offset) { return ret; } +static size_t pager_do_rw(pager_t *p, size_t offset, size_t len, char* buf, bool write) { + size_t ret = 0; + void* region = 0; + + mutex_lock(&p->lock); + + if (offset >= p->size) return 0; + if (offset + len > p->size) len = p->size - offset; + + size_t first_page = PAGE_ALIGN_DOWN(offset); + size_t region_len = offset + len - first_page; + + region = region_alloc(PAGE_ALIGN_UP(region_len), "Temporary pager read/write zone", 0); + if (region == 0) goto end_read; + + p->ops->page_in(p, first_page, region_len); + for (size_t i = first_page; i < first_page + region_len; i += PAGE_SIZE) { + uint32_t frame = (uint32_t)hashtbl_find(p->pages, (void*)i) >> ENT_FRAME_SHIFT; + if (frame == 0) goto end_read; + if (!pd_map_page(region + i - first_page, frame, write)) goto end_read; + } + + if (write) { + memcpy(region + offset - first_page, buf, len); + for (size_t page = first_page; page < first_page+ region_len; page += PAGE_SIZE) { + uint32_t v = (uint32_t)hashtbl_find(p->pages, (void*)page); + ASSERT(v != 0); + hashtbl_change(p->pages, (void*)page, (void*)(v | PAGE_ACCESSED)); + } + } else { + memcpy(buf, region + offset - first_page, len); + } + ret = len; + +end_read: + if (region) { + for (void* x = region; x < region + region_len; x += PAGE_SIZE) { + if (pd_get_frame(x) != 0) pd_unmap_page(x); + } + region_free(region); + } + mutex_unlock(&p->lock); + return ret; +} + +size_t pager_read(pager_t *p, size_t offset, size_t len, char* buf) { + return pager_do_rw(p, offset, len, buf, false); +} + +size_t pager_write(pager_t *p, size_t offset, size_t len, const char* buf) { + return pager_do_rw(p, offset, len, (char*)buf, true); +} + void pager_add_map(pager_t *p, user_region_t *reg) { mutex_lock(&p->lock); @@ -180,4 +307,18 @@ void pager_rm_map(pager_t *p, user_region_t *reg) { mutex_unlock(&p->lock); } +// ---- For use by FS drivers + +size_t fs_read_from_pager(fs_handle_t *f, size_t offset, size_t len, char* buf) { + ASSERT(f->node->pager != 0); + + return pager_read(f->node->pager, offset, len, buf); +} +size_t fs_write_to_pager(fs_handle_t *f, size_t offset, size_t len, const char* buf) { + ASSERT(f->node->pager != 0); + if (offset + len > f->node->pager->size) pager_resize(f->node->pager, offset + len); + + return pager_write(f->node->pager, offset, len, buf); +} + /* vim: set ts=4 sw=4 tw=0 noet :*/ |