diff options
Diffstat (limited to 'arch/i386/kernel/paging.c')
| -rw-r--r-- | arch/i386/kernel/paging.c | 141 |
1 files changed, 87 insertions, 54 deletions
diff --git a/arch/i386/kernel/paging.c b/arch/i386/kernel/paging.c index d8f72a3..54539ac 100644 --- a/arch/i386/kernel/paging.c +++ b/arch/i386/kernel/paging.c @@ -2,87 +2,120 @@ #include <kernel/io.h> #include <kernel/syscall.h> #include <kernel/string.h> -#include <kernel/alloc.h> -#include <stddef.h> -extern int halt_catch_fire(); -extern uint32_t _kernel_start; -extern uint32_t _kernel_end; -static uint32_t *kstart = &_kernel_start; -static uint32_t *kend = (uint32_t)(&_kernel_end) - 0xC0000000; +extern uintptr_t _kernel_start; +extern uintptr_t _kernel_end; +static uintptr_t kstart = (uintptr_t)&_kernel_start; +static uintptr_t kend = (uintptr_t)&_kernel_end - 0xC0000000; -static uint32_t page_directory[1024] __attribute__((aligned(PAGE_SIZE))); -static uint32_t first_page_table[1024] __attribute__((aligned(PAGE_SIZE))); +static uintptr_t page_directory[1024] __attribute__((aligned(PAGE_SIZE))); +static uintptr_t first_page_table[1024] __attribute__((aligned(PAGE_SIZE))); static int paging_enabled = 0; +static uint32_t dma_zone_bitmap[DMA_BITMAP_SZ]; +static uint32_t buddy_bitmap[BDY_BITMAP_SZ]; +static struct pfa_buddy first_buddy; + +static void _pfa_init(void) { + first_buddy.start = 0x01000000; + first_buddy.bitmap = buddy_bitmap; +} + +static void _pfa_alloc(uintptr_t paddr) { + uintptr_t index = (paddr & 0xFFFFF000) / 4096 / 32; + uintptr_t bit = (paddr & 0xFFFFF000) / 4096 % 32; + uint32_t *bitmap; + if (paddr < 0x01000000) + bitmap = dma_zone_bitmap; + else + bitmap = first_buddy.bitmap; + + bitmap[index] |= (1 << bit); +} + +static void _pfa_free(uintptr_t paddr) { + uintptr_t index = (paddr & 0xFFFFF000) / 4096 / 32; + uintptr_t bit = (paddr & 0xFFFFF000) / 4096 % 32; + uint32_t *bitmap; + if (paddr < 0x01000000) + bitmap = dma_zone_bitmap; + else + bitmap = first_buddy.bitmap; + + bitmap[index] &= ~(1 << bit); +} + void paging_init(void) { + _pfa_init(); for (int i = 0; i < 1024; i++) page_directory[i] = 0x00000002; - page_directory[1023] = ((uint32_t)&page_directory - 0xC0000000) | 3; - page_directory[0] = ((uint32_t)&first_page_table - 0xC0000000) | 3; - page_directory[768] = ((uint32_t)&first_page_table - 0xC0000000) | 3; - for (uint32_t i = kstart; i < kend; i += 4096) { - map_page(i, get_vaddr(i), 0x003); - mark_bitmap(i, 1); + page_directory[1023] = ((uintptr_t)&page_directory - 0xC0000000) | 3; + page_directory[0] = ((uintptr_t)&first_page_table - 0xC0000000) | 3; + page_directory[768] = ((uintptr_t)&first_page_table - 0xC0000000) | 3; + for (uintptr_t i = kstart; i < kend; i += 4096) { + _pfa_alloc(get_vaddr(i)); + map_page(page_directory, i, get_vaddr(i), 0x003); } - map_page(0xB8000, 0xC03FF000, 0x003); - mark_bitmap(0xB8000, 1); - - load_page_dir(((uint32_t)&page_directory) - 0xC0000000); + load_page_dir(((uintptr_t)&page_directory) - 0xC0000000); enable_paging(); paging_enabled = 1; return; } void page_fault_handler(struct isr_frame *frame) { - kprintf("Page fault detected\n"); - uint32_t errno = frame->errno; + uintptr_t errno = frame->errno; - uint32_t fault_addr; + uintptr_t fault_addr; __asm__ volatile("movl %%cr2, %0" : "=r"(fault_addr)); - kprintf("Fault occured at address %x\n", fault_addr); - uint32_t present = errno & ERR_PRESENT; - uint32_t rw = errno & ERR_RW; - uint32_t user = errno & ERR_USER; - uint32_t reserved = errno & ERR_RESERVED; - uint32_t ifetch = errno & ERR_INST; - kprintf("Possible causes:\n"); - if (!present) kprintf("\tPage not present\n"); - if (rw || user) kprintf("\tPage is read only\n"); - if (reserved) kprintf("\tOverwrote reserved bits\n"); - if (ifetch) kprintf("\tInstruction fetch\n"); - halt_catch_fire(frame); -} - -uint32_t get_paddr(uint32_t vaddr) { - uint32_t pdindex = vaddr >> 22; - uint32_t ptindex = vaddr >> 12 & 0x03FF; - - uint32_t *page_table = (page_directory[pdindex] + 0xC0000000 & 0xFFFFF000); - return (page_table[ptindex] & 0xFFFFF000) | (vaddr & 0x00000FFF); + int present = errno & ERR_PRESENT; + int rw = errno & ERR_RW; + int user = errno & ERR_USER; + int reserved = errno & ERR_RESERVED; + int ifetch = errno & ERR_INST; + + if (!present) + _pfa_alloc(fault_addr); + map_page(NULL, fault_addr, fault_addr, 0x003); + if (user) + panic("Usermode attempted to read supervisor page"); + if (rw) + panic("Task wrote to read only page"); + if (reserved) + panic("Task overwrote reserved page bits"); + if (ifetch) + panic("Task paging instruction fetch failure"); } -uint32_t get_vaddr(uint32_t paddr) { +uintptr_t get_vaddr(uintptr_t paddr) { return paddr + 0xC0000000; } -void map_page(uint32_t paddr, uint32_t vaddr, uint32_t flags) { - uint32_t pdindex = vaddr >> 22; - uint32_t ptindex = vaddr >> 12 & 0x03FF; +void map_page(uint32_t *pd, uintptr_t paddr, uintptr_t vaddr, uint32_t flags) { + if (pd == NULL) + pd = page_directory; + + uintptr_t paddr_aligned = paddr & 0xFFFFF000; + uintptr_t vaddr_aligned = vaddr & 0xFFFFF000; - uint32_t *page_table = (page_directory[pdindex] + 0xC0000000 & 0xFFFFF000); - uint32_t *pte = (uint32_t*)(&page_table[ptindex]); - *pte |= paddr | (flags & 0xFFF) | 0x01; + uintptr_t pdindex = vaddr_aligned >> 22; + uintptr_t ptindex = vaddr_aligned >> 12 & 0x03FF; + + uintptr_t *pt = (pd[pdindex] + 0xC0000000 & 0xFFFFF000); + uintptr_t *pte = (uintptr_t*)(&pt[ptindex]); + *pte |= paddr_aligned | (flags & 0xFFF) | 0x01; } -void unmap_page(uint32_t vaddr) { - uint32_t pdindex = vaddr >> 22; - uint32_t ptindex = vaddr >> 12 & 0x03FF; +void unmap_page(uint32_t *pd, uintptr_t vaddr) { + if (pd == NULL) + pd = page_directory; + + uintptr_t pdindex = vaddr >> 22; + uintptr_t ptindex = vaddr >> 12 & 0x03FF; - uint32_t *page_table = (page_directory[pdindex] + 0xC0000000 & 0xFFFFF000); - uint32_t *pte = (uint32_t*)(&page_table[ptindex]); + uintptr_t *pt = (pd[pdindex] + 0xC0000000 & 0xFFFFF000); + uintptr_t *pte = (uintptr_t*)(&pt[ptindex]); *pte &= 0; } |