diff options
Diffstat (limited to 'src/kernel')
| -rw-r--r-- | src/kernel/arch/amd64/boot.c | 11 | ||||
| -rw-r--r-- | src/kernel/linker.ld | 2 | ||||
| -rw-r--r-- | src/kernel/main.h | 8 | ||||
| -rw-r--r-- | src/kernel/mem/alloc.c | 74 | ||||
| -rw-r--r-- | src/kernel/proc.c | 2 |
5 files changed, 52 insertions, 45 deletions
diff --git a/src/kernel/arch/amd64/boot.c b/src/kernel/arch/amd64/boot.c index 2707223..2347df4 100644 --- a/src/kernel/arch/amd64/boot.c +++ b/src/kernel/arch/amd64/boot.c @@ -36,15 +36,17 @@ void kmain_early(struct multiboot_info *multiboot) { info.memtop = (void*)(long)(multiboot->mem_upper * 1024); find_init(multiboot, &info); + info.fb.at = (void*)multiboot->framebuffer_addr; + info.fb.size = multiboot->framebuffer_pitch * multiboot->framebuffer_height; kprintf("mem...\n"); mem_init(&info); - kprintf("rootfs..."); + kprintf("rootfs...\n"); vfs_root_init(); ps2_init(); serial_init(); - kprintf("ata..."); + kprintf("ata...\n"); ata_init(); vid.b = (void*)multiboot->framebuffer_addr; @@ -54,6 +56,11 @@ void kmain_early(struct multiboot_info *multiboot) { vid.bpp = multiboot->framebuffer_bpp; vid.size = vid.pitch * vid.height; + kprintf("kernel %8x -> %8x\n", 0, &_bss_end); + kprintf("init %8x -> %8x\n", info.init.at, info.init.at + info.init.size); + kprintf("video %8x -> %8x\n", vid.b, vid.b + vid.size); + kprintf("limit %8x\n", info.memtop); + kprintf("framebuffer at 0x%x, %ux%u bpp %u\n", vid.b, vid.width, vid.height, vid.bpp); video_init(vid); diff --git a/src/kernel/linker.ld b/src/kernel/linker.ld index 278548e..a910d4e 100644 --- a/src/kernel/linker.ld +++ b/src/kernel/linker.ld @@ -37,4 +37,6 @@ SECTIONS _stack_top = .; } _bss_end = (. + 0xFFF) & ~0xFFF; /* aligned to 4K */ + pbitmap = _bss_end; + pbitmap_start = _bss_end; } diff --git a/src/kernel/main.h b/src/kernel/main.h index e4ead31..edceb76 100644 --- a/src/kernel/main.h +++ b/src/kernel/main.h @@ -3,9 +3,13 @@ struct kmain_info { struct { - void *at; // page aligned + void *at; /* page aligned */ size_t size; - } init; // a boot module loaded by GRUB, containing the initrd driver + } init; /* a boot module loaded by GRUB, containing the initrd driver */ + struct { + void *at; + size_t size; + } fb; /* the framebuffer */ void *memtop; }; diff --git a/src/kernel/mem/alloc.c b/src/kernel/mem/alloc.c index a6f6b6d..c08b24a 100644 --- a/src/kernel/mem/alloc.c +++ b/src/kernel/mem/alloc.c @@ -17,32 +17,43 @@ struct malloc_hdr { struct malloc_hdr *malloc_last = NULL; +extern uint8_t pbitmap[], pbitmap_start[]; /* linker.ld */ +static size_t pbitmap_len; -static void *memtop; -static uint8_t *page_bitmap; -static void *page_bitmap_start; -static size_t page_bitmap_len; +static bool bitmap_get(size_t i) { + size_t b = i / 8; + assert(b < pbitmap_len); + return 0 < (pbitmap[b] & (1 << (i&7))); +} +static void bitmap_set(size_t i, bool v) { + size_t b = i / 8; + uint8_t m = 1 << (i&7); + assert(b < pbitmap_len); + if (v) pbitmap[b] |= m; + else pbitmap[b] &= ~m; +} -static void *closest_page(void *p) { - return (void*)(((uintptr_t)p + PAGE_MASK) & ~PAGE_MASK); +static void bitmap_mark(void *start, size_t len) { + /* align to the previous page */ + size_t off = (uintptr_t)start & PAGE_MASK; + start -= off; + len += off; + size_t first = ((uintptr_t)start - (uintptr_t)pbitmap_start) / PAGE_SIZE; + for (size_t i = 0; i * PAGE_SIZE < len; i++) { + if (first + i >= pbitmap_len) break; + bitmap_set(first + i, true); + } } void mem_init(struct kmain_info *info) { - memtop = info->memtop; - - /* place the page_bitmap right at the first free spot in memory */ - page_bitmap = max((void*)&_bss_end, closest_page(info->init.at + info->init.size)); - page_bitmap_len = ((uintptr_t)memtop - (uintptr_t)page_bitmap) / PAGE_SIZE / 8; - /* the page_bitmap_len calculation doesn't account for the space lost to itself, - * so just take away a few pages to account for it. this could be solved with - * actual math, but eh. */ - page_bitmap_len -= 8; - memset(page_bitmap, 0, page_bitmap_len); - - /* start allocation on the page immediately following the page bitmap */ - page_bitmap_start = closest_page(page_bitmap + page_bitmap_len); + size_t pageamt = ((uintptr_t)info->memtop - (uintptr_t)pbitmap_start) / PAGE_SIZE; + pbitmap_len = pageamt / 8; + memset(pbitmap, 0, pbitmap_len); + bitmap_mark(pbitmap, pbitmap_len); + bitmap_mark(info->init.at, info->init.size); + bitmap_mark(info->fb.at, info->fb.size); } void mem_debugprint(void) { @@ -59,25 +70,10 @@ void mem_debugprint(void) { kprintf(" total 0x%x\n", total); } -static bool bitmap_get(size_t i) { - size_t b = i / 8; - assert(b < page_bitmap_len); - return 0 < (page_bitmap[b] & (1 << (i&7))); -} - -static void bitmap_set(size_t i, bool v) { - size_t b = i / 8; - uint8_t m = 1 << (i&7); - assert(b < page_bitmap_len); - if (v) page_bitmap[b] |= m; - else page_bitmap[b] &= ~m; -} - void *page_alloc(size_t pages) { - // TODO can allocate in the framebuffer /* i do realize how painfully slow this is */ size_t streak = 0; - for (size_t i = 0; i < page_bitmap_len * 8; i++) { + for (size_t i = 0; i < pbitmap_len * 8; i++) { if (bitmap_get(i)) { streak = 0; continue; @@ -87,7 +83,7 @@ void *page_alloc(size_t pages) { i = i + 1 - streak; for (size_t j = 0; j < streak; j++) bitmap_set(i + j, true); - return page_bitmap_start + i * PAGE_SIZE; + return pbitmap_start + i * PAGE_SIZE; } } kprintf("we ran out of memory :(\ngoodbye.\n"); @@ -102,10 +98,8 @@ void *page_zalloc(size_t pages) { // frees `pages` consecutive pages starting from *first void page_free(void *first_addr, size_t pages) { - // TODO put init's pages into the allocator - if (first_addr < page_bitmap_start) - return; - size_t first = (uintptr_t)(first_addr - page_bitmap_start) / PAGE_SIZE; + assert(first_addr >= (void*)pbitmap_start); + size_t first = ((uintptr_t)first_addr - (uintptr_t)pbitmap_start) / PAGE_SIZE; for (size_t i = 0; i < pages; i++) { assert(bitmap_get(first + i)); bitmap_set(first + i, false); diff --git a/src/kernel/proc.c b/src/kernel/proc.c index 6bc7057..fd02f33 100644 --- a/src/kernel/proc.c +++ b/src/kernel/proc.c @@ -148,7 +148,7 @@ void process_kill(struct process *p, int ret) { p->execbuf.buf = NULL; } - pagedir_free(p->pages); // TODO put init's pages in the allocator + pagedir_free(p->pages); // TODO VULN unbounded recursion struct process *c2; |