用户虚拟地址转化成物理地址,物理地址转换成内核虚拟地址,内核虚拟地址转换成物理地址,虚拟地址和对应页的关系

时间:2025-02-16 07:37:53
static void get_pgtable_macro(void) { printk("PAGE_OFFSET = 0x%lx\n", PAGE_OFFSET); printk("PGDIR_SHIFT = %d\n", PGDIR_SHIFT); printk("PUD_SHIFT = %d\n", PUD_SHIFT); printk("PMD_SHIFT = %d\n", PMD_SHIFT); printk("PAGE_SHIFT = %d\n", PAGE_SHIFT); printk("PTRS_PER_PGD = %d\n", PTRS_PER_PGD); printk("PTRS_PER_PUD = %d\n", PTRS_PER_PUD); printk("PTRS_PER_PMD = %d\n", PTRS_PER_PMD); printk("PTRS_PER_PTE = %d\n", PTRS_PER_PTE); printk("PAGE_MASK = 0x%lx\n", PAGE_MASK); } static unsigned long vaddr2paddr(unsigned long vaddr) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; unsigned long paddr = 0; unsigned long page_addr = 0; unsigned long page_offset = 0; pgd = pgd_offset(current->mm, vaddr); printk("pgd_val = 0x%lx\n", pgd_val(*pgd)); printk("pgd_index = %lu\n", pgd_index(vaddr)); if (pgd_none(*pgd)) { printk("not mapped in pgd\n"); return -1; } pud = pud_offset(pgd, vaddr); printk("pud_val = 0x%lx\n", pud_val(*pud)); if (pud_none(*pud)) { printk("not mapped in pud\n"); return -1; } pmd = pmd_offset(pud, vaddr); printk("pmd_val = 0x%lx\n", pmd_val(*pmd)); printk("pmd_index = %lu\n", pmd_index(vaddr)); if (pmd_none(*pmd)) { printk("not mapped in pmd\n"); return -1; } pte = pte_offset_kernel(pmd, vaddr); printk("pte_val = 0x%lx\n", pte_val(*pte)); printk("pte_index = %lu\n", pte_index(vaddr)); if (pte_none(*pte)) { printk("not mapped in pte\n"); return -1; } //页框物理地址机制 | 偏移量 page_addr = pte_val(*pte) & PAGE_MASK; page_offset = vaddr & ~PAGE_MASK; paddr = page_addr | page_offset; printk("page_addr = %lx, page_offset = %lx\n", page_addr, page_offset); printk("vaddr = %lx, paddr = %lx\n", vaddr, paddr); return paddr; } static int __init v2p_init(void) { unsigned long vaddr = 0; printk("vaddr to paddr module is running..\n"); get_pgtable_macro(); printk("\n"); vaddr = (unsigned long)vmalloc(1000 * sizeof(char)); if (vaddr == 0) { printk("vmalloc failed..\n"); return 0; } printk("vmalloc_vaddr=0x%lx\n", vaddr); vaddr2paddr(vaddr); printk("\n\n"); vaddr = __get_free_page(GFP_KERNEL); if (vaddr == 0) { printk("__get_free_page failed..\n"); return 0; } printk("get_page_vaddr=0x%lx\n", vaddr); vaddr2paddr(vaddr); return 0; } static void __exit v2p_exit(void) { printk("vaddr to paddr module is leaving..\n"); vfree((void *)vaddr); free_page(vaddr); }