X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fuserprog%2Fpagedir.c;h=1442d4076067043f9ff35a516c999f2addff0cc3;hb=fde3b8ee3eaf48b1a6bb14568aedc207e62accab;hp=4604ca2ddf94b24e97f31fbd5d553b06ab3ff7c1;hpb=615bf3b3d2a8573ed6fb9ddc0055745e163ac999;p=pintos-anon diff --git a/src/userprog/pagedir.c b/src/userprog/pagedir.c index 4604ca2..1442d40 100644 --- a/src/userprog/pagedir.c +++ b/src/userprog/pagedir.c @@ -3,7 +3,7 @@ #include #include #include "threads/init.h" -#include "threads/mmu.h" +#include "threads/pte.h" #include "threads/palloc.h" static uint32_t *active_pd (void); @@ -18,7 +18,7 @@ pagedir_create (void) { uint32_t *pd = palloc_get_page (0); if (pd != NULL) - memcpy (pd, base_page_dir, PGSIZE); + memcpy (pd, init_page_dir, PGSIZE); return pd; } @@ -32,15 +32,15 @@ pagedir_destroy (uint32_t *pd) if (pd == NULL) return; - ASSERT (pd != base_page_dir); + ASSERT (pd != init_page_dir); for (pde = pd; pde < pd + pd_no (PHYS_BASE); pde++) - if (*pde & PG_P) + if (*pde & PTE_P) { uint32_t *pt = pde_get_pt (*pde); uint32_t *pte; for (pte = pt; pte < pt + PGSIZE / sizeof *pte; pte++) - if (*pte & PG_P) + if (*pte & PTE_P) palloc_free_page (pte_get_page (*pte)); palloc_free_page (pt); } @@ -85,16 +85,18 @@ lookup_page (uint32_t *pd, const void *vaddr, bool create) return &pt[pt_no (vaddr)]; } -/* Adds a mapping from user virtual page UPAGE to kernel virtual - address KPAGE in page directory PD. +/* Adds a mapping in page directory PD from user virtual page + UPAGE to the physical frame identified by kernel virtual + address KPAGE. UPAGE must not already be mapped. + KPAGE should probably be a page obtained from the user pool + with palloc_get_page(). If WRITABLE is true, the new page is read/write; otherwise it is read-only. Returns true if successful, false if memory allocation failed. */ bool -pagedir_set_page (uint32_t *pd, void *upage, void *kpage, - bool writable) +pagedir_set_page (uint32_t *pd, void *upage, void *kpage, bool writable) { uint32_t *pte; @@ -102,13 +104,13 @@ pagedir_set_page (uint32_t *pd, void *upage, void *kpage, ASSERT (pg_ofs (kpage) == 0); ASSERT (is_user_vaddr (upage)); ASSERT (vtop (kpage) >> PTSHIFT < ram_pages); - ASSERT (pd != base_page_dir); + ASSERT (pd != init_page_dir); pte = lookup_page (pd, upage, true); if (pte != NULL) { - ASSERT ((*pte & PG_P) == 0); + ASSERT ((*pte & PTE_P) == 0); *pte = pte_create_user (kpage, writable); return true; } @@ -116,9 +118,10 @@ pagedir_set_page (uint32_t *pd, void *upage, void *kpage, return false; } -/* Returns the kernel virtual address that user virtual address - UADDR is mapped to in PD, or a null pointer if UADDR is not - present. */ +/* Looks up the physical address that corresponds to user virtual + address UADDR in PD. Returns the kernel virtual address + corresponding to that physical address, or a null pointer if + UADDR is unmapped. */ void * pagedir_get_page (uint32_t *pd, const void *uaddr) { @@ -127,7 +130,7 @@ pagedir_get_page (uint32_t *pd, const void *uaddr) ASSERT (is_user_vaddr (uaddr)); pte = lookup_page (pd, uaddr, false); - if (pte != NULL && (*pte & PG_P) != 0) + if (pte != NULL && (*pte & PTE_P) != 0) return pte_get_page (*pte) + pg_ofs (uaddr); else return NULL; @@ -146,9 +149,9 @@ pagedir_clear_page (uint32_t *pd, void *upage) ASSERT (is_user_vaddr (upage)); pte = lookup_page (pd, upage, false); - if (pte != NULL && (*pte & PG_P) != 0) + if (pte != NULL && (*pte & PTE_P) != 0) { - *pte &= ~PG_P; + *pte &= ~PTE_P; invalidate_pagedir (pd); } } @@ -161,7 +164,7 @@ bool pagedir_is_dirty (uint32_t *pd, const void *vpage) { uint32_t *pte = lookup_page (pd, vpage, false); - return pte != NULL && (*pte & PG_D) != 0; + return pte != NULL && (*pte & PTE_D) != 0; } /* Set the dirty bit to DIRTY in the PTE for virtual page VPAGE @@ -173,10 +176,10 @@ pagedir_set_dirty (uint32_t *pd, const void *vpage, bool dirty) if (pte != NULL) { if (dirty) - *pte |= PG_D; + *pte |= PTE_D; else { - *pte &= ~(uint32_t) PG_D; + *pte &= ~(uint32_t) PTE_D; invalidate_pagedir (pd); } } @@ -190,7 +193,7 @@ bool pagedir_is_accessed (uint32_t *pd, const void *vpage) { uint32_t *pte = lookup_page (pd, vpage, false); - return pte != NULL && (*pte & PG_A) != 0; + return pte != NULL && (*pte & PTE_A) != 0; } /* Sets the accessed bit to ACCESSED in the PTE for virtual page @@ -202,10 +205,10 @@ pagedir_set_accessed (uint32_t *pd, const void *vpage, bool accessed) if (pte != NULL) { if (accessed) - *pte |= PG_A; + *pte |= PTE_A; else { - *pte &= ~(uint32_t) PG_A; + *pte &= ~(uint32_t) PTE_A; invalidate_pagedir (pd); } } @@ -217,13 +220,14 @@ void pagedir_activate (uint32_t *pd) { if (pd == NULL) - pd = base_page_dir; + pd = init_page_dir; /* Store the physical address of the page directory into CR3 aka PDBR (page directory base register). This activates our new page tables immediately. See [IA32-v2a] "MOV--Move - to/from Control Registers" and [IA32-v3] 3.7.5. */ - asm volatile ("mov %%cr3, %0" :: "r" (vtop (pd))); + to/from Control Registers" and [IA32-v3a] 3.7.5 "Base + Address of the Page Directory". */ + asm volatile ("movl %0, %%cr3" : : "r" (vtop (pd)) : "memory"); } /* Returns the currently active page directory. */ @@ -233,9 +237,9 @@ active_pd (void) /* Copy CR3, the page directory base register (PDBR), into `pd'. See [IA32-v2a] "MOV--Move to/from Control Registers" and - [IA32-v3] 3.7.5. */ + [IA32-v3a] 3.7.5 "Base Address of the Page Directory". */ uintptr_t pd; - asm volatile ("mov %0, %%cr3" : "=r" (pd)); + asm volatile ("movl %%cr3, %0" : "=r" (pd)); return ptov (pd); } @@ -252,9 +256,8 @@ invalidate_pagedir (uint32_t *pd) { if (active_pd () == pd) { - /* We cleared a page-table entry in the active page - table, so we have to invalidate the TLB. See - [IA32-v3], section 3.11. */ + /* Re-activating PD clears the TLB. See [IA32-v3a] 3.12 + "Translation Lookaside Buffers (TLBs)". */ pagedir_activate (pd); } }