//pmm_init - setup a pmm to manage physical memory, build PDT&PT to setup paging mechanism
// - check the correctness of pmm & paging mechanism, print PDT&PT
void
pmm_init(void) {
init_pmm_manager ();
page_init ();
#ifndef NOCHECK
//check_alloc_page();
#endif
boot_pgdir = boot_alloc_page ();
memset (boot_pgdir, 0, PGSIZE);
boot_pgdir_pa = PADDR (boot_pgdir);
current_pgdir_pa = boot_pgdir_pa;
#ifndef NOCHECK
//check_pgdir ();
#endif
static_assert(KERNBASE % PTSIZE == 0 && KERNTOP % PTSIZE == 0);
boot_pgdir[PDX(VPT)] = PADDR(boot_pgdir) | PTE_P | PTE_SPR_R | PTE_SPR_W | PTE_A | PTE_D;
boot_map_segment(boot_pgdir, KERNBASE, RAM_SIZE, 0, PTE_SPR_R | PTE_SPR_W | PTE_A | PTE_D);
enable_paging ();
#ifndef NOCHECK
//check_boot_pgdir ();
#endif
print_pgdir (kprintf);
slab_init ();
}
//pmm_init - setup a pmm to manage physical memory, build PDT&PT to setup paging mechanism
// - check the correctness of pmm & paging mechanism, print PDT&PT
void
pmm_init(void) {
//We need to alloc/free the physical memory (granularity is 4KB or other size).
//So a framework of physical memory manager (struct pmm_manager)is defined in pmm.h
//First we should init a physical memory manager(pmm) based on the framework.
//Then pmm can alloc/free the physical memory.
//Now the first_fit/best_fit/worst_fit/buddy_system pmm are available.
init_pmm_manager();
// detect physical memory space, reserve already used memory,
// then use pmm->init_memmap to create free page list
page_init();
//use pmm->check to verify the correctness of the alloc/free function in a pmm
check_alloc_page();
// create boot_pgdir, an initial page directory(Page Directory Table, PDT)
boot_pgdir = boot_alloc_page();
memset(boot_pgdir, 0, PGSIZE);
boot_cr3 = PADDR(boot_pgdir);
check_pgdir();
static_assert(KERNBASE % PTSIZE == 0 && KERNTOP % PTSIZE == 0);
// recursively insert boot_pgdir in itself
// to form a virtual page table at virtual address VPT
// cprintf("haah1\n");
// map all physical memory to linear memory with base linear addr KERNBASE
//linear_addr KERNBASE~KERNBASE+KMEMSIZE = phy_addr 0~KMEMSIZE
//But shouldn't use this map until enable_paging() & gdt_init() finished.
boot_map_segment(boot_pgdir, 0, KMEMSIZE, 0, PTE_TYPE_URWX_SRWX | PTE_R | PTE_V);
boot_pgdir[PDX(VPT)] = PADDR(boot_pgdir) | PTE_TYPE_TABLE | PTE_R | PTE_V;
// pgdir_alloc_page(boot_pgdir, USTACKTOP-PGSIZE , PTE_TYPE_URW_SRW);
//cprintf("haha2\n");
//temporary map:
//virtual_addr 3G~3G+4M = linear_addr 0~4M = linear_addr 3G~3G+4M = phy_addr 0~4M
//boot_pgdir[0] = boot_pgdir[PDX(KERNBASE)];
//cprintf("OK!\n");
enable_paging();
// cprintf("haah\n");
//reload gdt(third time,the last time) to map all physical memory
//virtual_addr 0~4G=liear_addr 0~4G
//then set kernel stack(ss:esp) in TSS, setup TSS in gdt, load TSS
//gdt_init();
//disable the map of virtual_addr 0~4M
//boot_pgdir[0] = 0;
//now the basic virtual memory map(see memalyout.h) is established.
//check the correctness of the basic virtual memory map.
check_boot_pgdir();
print_pgdir();
kmalloc_init();
}
/**
* Initialize page management mechanism.
* Parts of no use are deleted, while no extra parts except a check is added.
* arch/x86/mm/pmm.c should be a good reference.
*/
void
pmm_init (void)
{
check_vpm ();
init_pmm_manager ();
page_init ();
check_alloc_page ();
boot_pgdir = boot_alloc_page();
memset(boot_pgdir, 0, PGSIZE);
check_pgdir();
/* register kernel code and data pages in the table so that it won't raise bad segv. */
boot_map_segment (boot_pgdir, KERNBASE, mem_size, 0, PTE_W);
check_boot_pgdir ();
print_pgdir (kprintf);
slab_init ();
}
