154 lines
3.7 KiB
C
154 lines
3.7 KiB
C
#include <assert.h>
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#include <elf.h>
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#include <string.h>
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#include <mmu.h>
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#include <kern/kmalloc.h>
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#include <kern/pmap.h>
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/*
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* 申请一个新的物理页，并更新page_list页面信息
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* 返回新申请的物理页面的物理地址
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*/
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static phyaddr_t
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alloc_phy_page(struct page_node **page_list)
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{
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phyaddr_t paddr = phy_malloc_4k();
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struct page_node *new_node = kmalloc(sizeof(struct page_node));
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new_node->nxt = *page_list;
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new_node->paddr = paddr;
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new_node->laddr = -1;
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*page_list = new_node;
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return paddr;
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}
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/*
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* MINIOS中比较通用的页表映射函数
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* 它将laddr处的虚拟页面映射到物理地址为paddr（如果paddr为-1则会自动申请一个新的物理页面）的物理页面
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* 并将pte_flag置位到页表项（页目录项标志位默认为PTE_P | PTE_W | PTE_U）
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* 这个函数中所有新申请到的页面信息会存放到page_list这个链表中
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*/
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static void
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lin_mapping_phy(u32 cr3,
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struct page_node **page_list,
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uintptr_t laddr,
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phyaddr_t paddr,
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u32 pte_flag)
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{
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assert(PGOFF(laddr) == 0);
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uintptr_t *pde_ptr = (uintptr_t *)K_PHY2LIN(cr3);
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if ((pde_ptr[PDX(laddr)] & PTE_P) == 0) {
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phyaddr_t pte_phy = alloc_phy_page(page_list);
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memset((void *)K_PHY2LIN(pte_phy), 0, PGSIZE);
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pde_ptr[PDX(laddr)] = pte_phy | PTE_P | PTE_W | PTE_U;
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}
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phyaddr_t pte_phy = PTE_ADDR(pde_ptr[PDX(laddr)]);
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uintptr_t *pte_ptr = (uintptr_t *)K_PHY2LIN(pte_phy);
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phyaddr_t page_phy;
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if (paddr == (phyaddr_t)-1) {
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if ((pte_ptr[PTX(laddr)] & PTE_P) != 0)
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return;
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page_phy = alloc_phy_page(page_list);
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(*page_list)->laddr = laddr;
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} else {
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if ((pte_ptr[PTX(laddr)] & PTE_P) != 0)
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warn("this page was mapped before, laddr: %x", laddr);
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assert(PGOFF(paddr) == 0);
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page_phy = paddr;
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}
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pte_ptr[PTX(laddr)] = page_phy | pte_flag;
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}
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/*
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* 初始化进程页表的内核部分
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* 将3GB ~ 3GB + 128MB的线性地址映射到0 ~ 128MB的物理地址
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*/
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void
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map_kern(u32 cr3, struct page_node **page_list)
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{
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for (phyaddr_t paddr = 0 ; paddr < 128 * MB ; paddr += PGSIZE) {
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lin_mapping_phy(cr3,
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page_list,
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K_PHY2LIN(paddr),
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paddr,
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PTE_P | PTE_W | PTE_U);
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}
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}
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/*
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* 根据elf文件信息将数据搬迁到指定位置
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* 中间包含了对页表的映射，eip的置位
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* 这也是你们做实验五中最折磨的代码，可以看这份学习一下
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*/
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void
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map_elf(PROCESS_0 *p_proc, void *elf_addr)
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{
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assert(p_proc->lock != 0);
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struct Elf *eh = (struct Elf *)elf_addr;
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struct Proghdr *ph = (struct Proghdr *)(elf_addr + eh->e_phoff);
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for (int i = 0 ; i < eh->e_phnum ; i++, ph++) {
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if (ph->p_type != PT_LOAD)
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continue;
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uintptr_t st = ROUNDDOWN(ph->p_va, PGSIZE);
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uintptr_t en = ROUNDUP(st + ph->p_memsz, PGSIZE);
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for (uintptr_t laddr = st ; laddr < en ; laddr += PGSIZE) {
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u32 pte_flag = PTE_P | PTE_U;
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if ((ph->p_flags & ELF_PROG_FLAG_WRITE) != 0)
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pte_flag |= PTE_W;
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lin_mapping_phy(p_proc->cr3,
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&p_proc->page_list,
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laddr,
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(phyaddr_t)-1,
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pte_flag);
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}
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memcpy( (void *)ph->p_va,
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(const void *)eh + ph->p_offset,
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ph->p_filesz);
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memset( (void *)ph->p_va + ph->p_filesz,
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0,
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ph->p_memsz - ph->p_filesz);
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}
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p_proc->user_regs.eip = eh->e_entry;
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}
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/*
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* 将用户栈映射到用户能够访问到的最后一个页面
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* (0xbffff000~0xc0000000)
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* 并将esp寄存器放置好
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*/
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void
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map_stack(PROCESS_0 *p_proc)
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{
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assert(p_proc->lock != 0);
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lin_mapping_phy(p_proc->cr3,
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&p_proc->page_list,
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K_PHY2LIN(-PGSIZE),
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(phyaddr_t)-1,
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PTE_P | PTE_W | PTE_U);
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p_proc->user_regs.esp = K_PHY2LIN(0);
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}
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/*
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* 根据page_list回收所有的页面（包括回收页面节点）
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*/
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void
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recycle_pages(struct page_node *page_list)
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{
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for (struct page_node *prevp, *p = page_list ; p ;) {
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phy_free_4k(p->paddr);
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prevp = p, p = p->nxt;
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kfree(prevp);
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}
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} |